MICROVASCULAR FREE TISSUE RECONSTRUCTION SELECTED …€¦ · MICROVASCULAR FREE TISSUE...

SROMS 1 VOLUME 12.4

MICROVASCULAR FREE TISSUE RECONSTRUCTION OF THE ORALCAVITY

Dongsoo David Kim, DMD, MD and G.E. Ghali, DDS, MD, FACS

INTRODUCTION

The estimated 20,000 new cases of oral cavity carcinoma occurring annually in the United States provide a vast population of patients who may require reconstructive surgery for their surgical defects.1 The functional and anatomical complexity of the head and neck can make the reconstruction of these defects a daunting task. Although not all patients with oral cancer will have surgery as their primary mode of therapy, surgery is generally considered the preferred method of treatment for all but the most advanced disease if the patient is medically fit. With greater emphasis on early detection, more of these patients are being identified in earlier stages of disease, resulting in less need for complex reconstruc-tion. Currently, however, more than 50% of oral cavity cancers are diagnosed in the advanced stages of disease (Stage III or IV)2, and in these cases surgery can leave large, functionally crippling defects.

Although there is some debate, Alexis Carrel is credited for the standardization of end-to-end vascular anastomoses in 1902.3 He was awarded the Nobel Prize in Medicine and Physi-ology in 1912 for this work. However, the use of these techniques in small vessels was extremely limited due to inadequate instrumentation and magnification. Although Nylen introduced the operating microscope to clinical surgery in 1921,4 it wasn’t until 1960 that Jacobson used it for microvascular anastomoses in animal vessels as small as 1.4 mm in diameter.5 Buncke breached the 1 mm threshold for vessel anasto-mosis in 1964 when he successfully replanted a rabbit ear with vessels of 1 mm in diameter.6 For this accomplishment, he is considered by many to be the “father” of microvascular surgery. The first microvascular tissue transfer to the head and neck is also debated. As early as 1957, a free jejunal flap for an esophageal defect was

reported by Seidenberg, et al.7 However, others credit McLean and Buncke with the transplant of omentum to fill a large scalp defect in 1969.8 Panje, et al. (1974) are recognized as the first to use free tissue transfer for oral cavity recon-struction.9

Jacobson coined the term “microvascular surgery” in his work with the operating micro-scope in vascular anastomosis, and its advance-ment parallels the improvement of microscopes, micro-instrumentation and the manufacturing of ultra-fine suture materials and needles. Many of the pioneers of microvascular surgery developed their own suture materials and instrumentation that were modified from jeweler’s instruments.

ADVANTAGES AND DISADVANTAGES OF FREE TISSUE TRANSFER

Microvascular Free Tissue Reconstruction D. D. Kim, DMD, MD; G. E. Ghali DDS, MD,

SROMS 36 VOLUME 12.4

75. Taylor GI, Miller DH and Ham FJ: The free vascularized bone graft: a clinical extension of microvascular techniques. Plast Reconstr Surg 55:533, 1975.

76. Hidalgo D: Fibular free flap: a new method of mandible reconstruction. Plast Reconstr Surg 84:71, 1989.

77. Lorenz RR and Esclamado R: Preoperative magnetic resonance angiography in fibular free flap reconstruction of head and neck defects. Head Neck. 23:844, 2001.

78. Karakas YL, Antony A, Rubin G, et al: Pre-operative CT angiography for free fibular transfer. Microsurg. 24:125, 2004.

79. Lutz BS, Wei FC, Ng SH, et al: Routing donor leg angiography before vascularized free fibula transplantation is not necessary: a prospec-tive study in 120 cases. Plast Reconstr Surg 103:121, 1999.

80. Kessler P, Wiltfang J, Schultze-Mosqau S, et al: The role of angiography in the lower extremity using free vascularized fibular transplants for mandibular reconstruction. J Cranio-Maxillo-fac Surg 29:332, 2001.

81. Fleming A, Brough M, Evans N, et al: Mandib-ular reconstruction using vascularized fibula. Br J Plast Surg 43:403, 1990.

82. Taylor GI, Townsend P and Corlett R: Supe-riority of the deep circumflex iliac vessels as the supply for free groin flaps: experimental work. Plast Reconstr Surg 64:595, 1979.

83. Ramasastry SS, Granick MS and Futrell J: Clinical anatomy of the internal oblique mus-cle. J Reconstr Microsurg 2:117, 1986.

84. Urken ML. Free flaps. Composite free flaps. Iliac crest osteocutaneous and osteomuscu-lo-cutaneous. IN: Urkin ML, Cheney ML, Sulliven, MJ, Biller, HF (eds.) Atlas of Re-gional and Free Flaps for Head and Neck Reconstruction. Raven Press. New York, NY.

1995, pp. 261-290.

Related Articles From SELECTED READINGS IN ORAL AND MAXILLOFACIAL SUR-GERY.

The Use of Flaps for Reconstruction in Oral and Max-illofacial Surgery. John P. Kelly, DMD, MD. Selected Readings in Oral and Maxillofacial Surgery, Vol. 2, # 7, 1993.

Management of the Neck Relative to Oral Malignan-cy. G.E. Ghali, DDS, MD; Benjamin D.L., Li, MD; Emery A. Minnard, MD. Selected Readings in Oral and Maxillofacial Surgery, Vol. 6, #2, 1998.

Selected Hematology Conditions for the Oral & Max-illofacial Surgeon: Bleeding Disorders. Scott G. Lilly, DDS, MD; Gilbert E. Lilly, DDS. Selected Readings in Oral and Maxillofacial Surgery, Vol. 8, #6, 2000.


SROMS 2 VOLUME 12.4

Foremost of the advantages of MFTT is the ability to tailor the donor flap to the specific needs of the ablative site.

The concept of microvascular free tissue transfer (MFTT) after tumor extirpation has not been universally embraced as the standard in head and neck reconstruction. In fact, there are many who espouse the use of regional flaps, delayed non-vascularized bone grafts or both in these reconstructions.10 To some practitioners the numerous advantages of free tissue transfer do not offset their disadvantages, and it is true that not all patients will be suitable or will agree to have free flap reconstruction of their oral cavity defects.

Foremost of the advantages of MFTT is the ability to tailor the donor flap to the specific needs of the ablative site. For example, a thin and pliable radial forearm flap would be ideal for a partial defect of the floor of mouth or tongue, whereas the muscular bulk and large skin paddle of a rectus abdominus flap would be better suited for total glossectomy or maxillectomy defects. Indeed, pedicled flaps are less suitable for de-fects that need either extreme bulk of tissue or very thin, pliable tissue.

MFTT also has the advantage of not being restricted by the arc of rotation of the pedicle.

Free flaps can be placed in areas that may not easily be reached by rotational flaps, although recipient vessels must be nearby. In many cases of MFTT, if a longer vascular pedicle is needed greater length of the donor vessels can be dis-sected or vein grafts may be utilized.

Another advantage of MFTT is that it is a more efficient use of harvested tissue because nearly all of it is used directly for the reconstruc-tion. In contrast, most rotational flaps require

mobilization of large amounts of tissue, but only a relatively small area is used for the actu-al reconstruction. Because microvascular flap reconstructions bring their own blood supply, they are well suited to placement in inhospi-table areas such as the oral cavity. Here, their excellent perfusion can improve wound healing and protect against wound breakdown. MFTT of bone-containing flaps practically eliminates the resorption of bone seen in non-vascularized bone grafts. The use of primary microvascular reconstruction has allowed for more aggressive ablative surgery with clear margins even in very large tumors.11 Other possible advantages of MFTT include: 1) the possibility of neural anastomoses for the theoretical fabrication of a sensate flap,15 2) possible superior functional outcomes, and 3) a possibly improved quality of life.

Due to the increased operating time and need for technical expertise, MFTT is often per-ceived as being a less reliable and more costly procedure than rotational flap reconstruction. However, several studies comparing MFTT to rotational flaps for reconstruction of the head and neck have suggested that this may not be

true. In an often quoted article, Brown, et al.12 showed that the risk of postoperative compli-cations in patients who underwent free flap reconstruction was not significantly greater than those matched patients who received pedicled flap reconstruction. Their data suggested a trend toward shorter ICU stays and overall hospital stays with MFTT, although the differences were not statistically significant. In addition, several retrospective reviews identified the pectoralis major myocutaneous flap as having a higher



56. Quraishi HA, Was MK, Granke K, et al: Internal jugular vein thrombosis after func-tional and selective neck dissection. Arch Otolaryngol Head Neck Surg 123:969, 1997.

57. Samaha FJ, Oliva A, Buncke GM, et al: A clinical study of end-to-end versus end-to-side techniques for microvascular anastomosis. Plast Reconstr Surg 99:1109, 1997.

58. Sasmor MT, Reus WF, Straker DJ, et al: Vas-cular resistance considerations in free-tissue transfers. J Reconstr Microsurg 8:195, 1992.

59. Chalian AA, Anderson TD, Seinstein GS, et al: Internal jugular vein versus external jugular vein anastomosis: implications for successful free tissue transfer. Head Neck 23:475, 2001.

60. Hui KC, Zhang F, Shaw WW, et al: Assessment of the patency of microvascular venous anas-tomosis. J Reconstr Microsurg 18:111, 2002.

61. Chepeha DB, Nussenbaum B, Bradford CR, et al: Leech therapy for patients with surgically unsalvageable venous obstruction after revas-cularized free tissue transfer. Arch Otolaryngol Head Neck Surg. 128:960, 2002.

62. Kubo T, Yano K and Hosokawa K: Man-agement of flaps with compromised venous outflow in head and neck microsurgical re-construction. Microsurgery 22:391, 2002.

63. Soutar DS, Scheker CR, Tanner NSB, et al: The radial forearm flap: A versatile method for intraoral reconstruction. Br J Plast Surg. 36:1, 1983.

64. Urken ML: Free flaps. Fascial and fasciocu-taneous flaps. Radial forearm. IN: Urkin ML, Cheney ML, Sulliven, MJ, Biller, HF (eds.) Atlas of Regional and Free Flaps for Head and Neck Reconstruction. Raven Press. New York, NY. 1995, pp. 149-168.

65. Koshima I, Moriguchi T, Fukuda H, et al: Free thinned paraumbilical perforator-based flaps. J Reconstr Microsurg 7:313, 1991.

66. Boyd JB, Taylor GI and Corlett R: The vas-cular territories of the superior epigastric and the deep inferior epigastric systems. Plast Reconstr Surg 73:1, 1984.

67. Urken ML: Free flaps. Muscle and musculo-cutaneous flaps. Rectus Abdominis. IN: Urkin ML, Cheney ML, Sulliven, MJ, Biller, HF (eds.) Atlas of Regional and Free Flaps for Head and Neck Reconstruction. Raven Press. New York, NY. 1995, pp. 119-138.

68. Taylor GI and Palmer JH: The vascular terri-tories (angiosomes) of the body: Experimental study and clinical application. Br J Plast Surg 40:113, 1987.

69. Hallock GG: Direct and indirect perforator flaps: The history and the controversy. Plast Reconstr Surg 111: 855, 2003.

70. Song YG, Chen GZ and Song YL: The free thigh flap: a new free flap concept based on the septocutaneous artery. Br J Plast Surg 37: 149, 1984.

71. Koshima I, Fukuda H, Yamamoto H, et al: Free anterolateral thigh flaps for reconstruction of head and neck defects. Plast Reconstr Surg 92:421, 1993.

72. Wei FC, Jain V, Celik N, et al: Have we found an ideal soft-tissue flap? An experience with 672 anterolateral thigh flaps. Plast Reconstr Surg 109:2219, 2002.

73. Kimata Y, Uchiyama K, Ebihara S, et al: Ana-tomic variations and technical problems of the anterolateral thigh flap: A report of 74 cases. Plast Reconstr Surg 102:1517, 1998.

74. Celik N, Wei FC, Lin CH, et al: Technique and strategy in anterolateral thigh perforator flap surgery, based on an analysis of 15 complete and partial failures in 439 cases. Plast Reconstr Surg 109:2211, 2002.


SROMS 3 VOLUME 12.4

The risk of postoperative complications in patients who underwent free flap re-construction was not significantly greater than those matched patients who received pedicled flap reconstruction.

risk of major postoperative complications such as fistula formation, flap loss, infection and hematoma compared with radial forearm13 or rectus abdominus flaps.14

PATIENT MANAGEMENT

Preoperative

Preoperative patient evaluation is of para-mount importance for multiple reasons. It allows the reconstructive surgeon to: 1) identify any contraindications to MFTT, 2) estimate the size and shape of the expected defect and the need for reconstruction, 3) identify the ideal donor site, 4) perform appropriate preoperative testing, 5) verify the patient’s medical and emotional fit-ness to undergo the procedure, and 6) formulate alternative reconstructive options.

As with any pre-surgical assessment, evaluation of the microvascular reconstruction candidate should begin with a thorough history, including any co-morbid disease states, medica-tions and allergies. The patient’s social history should also be elicited at this time. Although absolute contraindications for microvascular surgery are rare, several common disease states (discussed below) may serve as relative contra-indications and direct the treatment plan toward more conventional reconstructive techniques. The impact of many of these conditions on microvascular reconstructive surgery is contro-versial.

The disadvantages of MFTT include the technical demands on the surgical team, oper-ating room staff, anesthesiology and the ICU. The initial anesthetic time for MFTT is longer than for non-microvascular reconstructions, but studies have shown that the overall cost, length of hospital and ICU stay, and incidence of complications is not significantly increased with MFTT.12,16 The potential for total flap loss is also a distinct disadvantage of MFTT. Even the most experienced microsurgeons will have a 5% to 10% failure rate, usually due to throm-bosis. However, as mentioned previously, the radial forearm and rectus abdominus flaps have shown lower incidence of flap loss than the pectoralis myocutaneous flap.13,14 Some series show the incidence of major complications for pectoralis myocutaneous flaps to be as high as 58%17 compared to reports of MFTT failure and reexploration rates of 2%-8% and 6%-14% respectively in two large series.18,19 The current state of MFTT has evolved from a radical, last

resort procedure with a high failure rate to the first and most reliable choice in all types of reconstruction, including head and neck defects.

Donor site morbidity is of great concern to reconstructive surgeons. A hallmark of the pectoralis major myocutaneous flap is its limited donor site morbidity. Different free flap donor sites have very different morbidity profiles and will be discussed later in this text. However, many of the most commonly used flaps, such as the radial forearm, fibula, rectus abdominus, and recently the anterolateral thigh flaps, have very acceptable levels of postoperative morbidity



38. Khouri RK, Cooley BC, Kenna DM, et al: Thrombosis of microvascular anastomoses in traumatized vessels: Fibrin versus platelets. Plast Reconstr Surg 86:110, 1990.

39. Vlastou C and Earle AS: Intraoperative heparin in replantation surgery: Experimental study. Ann Plast Surg 10:112, 1983.

40. Das SK and Miller JH: Current status of top-ical antithrombotic agents in microvascular surgery. Microsurgery 15:630, 1994.

41. Johnson PC and Barker JH: Thrombosis and antithrombotic therapy in microvascular sur-gery. Clin Plast Surg 19:799, 1992.

42. Pomerance J, Truppa K, et al., Replantation and revascularization of the digits in a com-munity microsurgical practice. J Reconstr Microsurg 13: 163, 1997.

43. Peter FW, Steinau HU, Homann HH, et al: Aspirin and microvascular surgery: an update. Plast Reconstr Surg 112:1368, 2003.

44. Peter FW, Franken RJPM, Wang WZ, et al: Ef-fect of low dose aspirin on thrombus formation at arterial and venous microana-stomoses and on the tissue microcirculation. Plast Reconstr Surg 99:112, 1997.

45. Disa JJ, Polvora VP, Pusic AL, et al: Dex-tran-related complications in head and neck microsurgery: Do the benefits outweigh the risk? A prospective randomized analysis. Plast Reconstr Surg 112:1534, 2003.

46. Renck H, Ljungstrom KG, Rosenberg B, et al: Prevention of dextran-induced anaphylactic reactions by hapten inhibition: II. A compar-ison of the effects of 20ml Dextran 1, 15% administered either admixed or before dextran 70 or dextran 40. Acta Chir Scand. 149:349, 1983.

47. Esclamado RM and Carroll WR: The patho-genesis of vascular thrombosis and its impact in microvascular surgery. Head Neck 21:355, 1999.

48. Walenga JM, Pifarre R, Hoppensteadt DA, et al: Development of recombinant hirudin as a therapeutic anticoagulant and antithrombotic agent: Some objective considerations. Thromb Haemost. 15:316, 1989.

49. Khouri RK, Sherman R Buncke HJ, et al: A phase II trial of intraluminal irrigation with recombinant human tissue factor pathway inhibitor to prevent thrombosis in free flap surgery. Plast Reconstr Surg. 107:408, 2001.

50. Ching S, Thoma A, Monkman J, et al: In-hibition of microsurgical thrombosis by the platelet glycoprotein IIb/IIIa antagonist SR121566A. Plast Reconstr Surg 112:177. 2003.

51. Urken ML: Recipient vessel selection in free tissue transfer to the head and neck. IN: Urkin ML, Cheney ML, Sulliven, MJ, Biller, HF (eds.) Atlas of Regional and Free Flaps for Head and Neck Reconstruction. Raven Press, New York, NY. 1995, pp. 331-337.

52. Shusterman MA, Miller MJ, et al., A single center’s experience with 308 free flaps for repair of head and neck cancer defects. Plast Reconstr Surg 93: 472, 1994.

53. Varvares MA and Cheney ML: Free flaps for head and neck reconstruction. IN: Cheney ML (ed.) Facial Surgery, Plastic and Reconstruc-tive. Williams and Wilkins, Baltimore, MD. 1997, pp. 487-507.

54. Chalian AA, Anderson TD, Weinstein GS, et al: Internal jugular vein versus external jugular vein anastomosis: implications for successful free tissue transfer. Head Neck 23:475, 2001

55. Yamamoto Y, Nohira K, Kuwahara H, et al: Superiorty of end-to-side anastomosis with the internal jugular vein: the experience of 80 cases in head and neck microsurgical recon-struction. Br J Plast Surg 52:88, 1999.


SROMS 4 VOLUME 12.4

with few long term deficits.

Hypercoagulable states are the only true contraindications to MFTT. (Table 1).20 This includes diseases such as polycythemia, throm-bocytosis and possibly sickle cell anemia The risk of thrombosis in these conditions is too high to justify MFTT. Patients taking the anti-es-trogen medication tamoxifen for prevention or treatment of breast cancer should be taken off this medication prior to surgery due to its known thrombogenic activity.21 For similar reasons, as well as decreased flap perfusion and impaired wound healing, smokers should be encouraged to stop smoking at least one week prior to sur-gery.

Hypercoagulable states are the only true contraindications to MFTT.

Age has not been shown to be a signifi-cant risk factor for postoperative complications with MFTT. Although studies have implied that advanced age has a greater risk for prolonged hospital stay, medical complication and in-hos-pital death;22,23 others have shown no significant difference in complications following major head and neck reconstructive surgery.24 How-ever, advanced age is associated with athero-sclerotic disease and increased vessel fragility which may pose a specific, though not absolute, problem in MFTT. Conversely, pediatric patients may have very small caliber vessels that will make anastomosis difficult and less reliable, especially when the vessels are less than 1mm in diameter.

Diabetes can predispose patients to microvascular disease and atherosclerosis which may result in delayed wound healing, infection and possible flap loss. Atherosclerosis is most problematic when evaluating the patient for har-

vest of the fibula flap and this will be discussed later. However, the influence of atherosclerosis on microvascular anastomoses is not known.

After a thorough medical history is obtained, evaluation of the lesion should be per-formed, noting its location, size and involvement of adjacent tissues. The extent of the resection is estimated and the best donor site is chosen ac-cording to this prediction. A detailed description of the proposed procedure should be discussed with the patient and their family, delineating the risks, benefits, capabilities and limitations of the reconstruction. This dialogue will help the reconstructive surgeon determine if the patient and family are emotionally suitable candidates for microvascular reconstruction.

Preoperative testing should be ordered as well as specific tests for the proposed donor site or sites. Specific tests will be discussed with each flap design in later sections, including Allen’s test for radial forearm flap candidates and evaluation of distal pulses and extremity angiography for fibula flaps.

Postoperative

The postoperative management of patients receiving MFTT is as important as the intra-operative MFTT technique. Protocols vary by institution and are not based on scientific evi-dence of efficacy but rather surgeon preference, personal experience and possibly superstition. However, certain standards should be applied to all free flap reconstructions regardless of the site.

Pressure on the microvascular pedicle should be avoided at all times. In head and neck reconstruction, circumferential ties or straps



16. Huang RD, Silver SM, Hussain A, et al: Pec-toralis major myocutaneous flap: Analysis of complications in a VA population. Head Neck. 14:102, 1992.

17. Kroll SS, Schusterman MA and Reece GP: Costs and complications in mandibular recon-struction. Ann Plast Surg. 29:341, 1992.

18. Disa JJ, Pusic AL, Hidalgo DH, et al: Sim-plifying microvascular head and neck recon-struction: a rational approach to donor site selection. Ann Plast Surg. 47:385, 2001.

19. Haughey BH, Wilson E, Kluwe L, et al: Free flap reconstruction of the head and neck: Analysis of 241 cases. Otolaryngol Head Neck Surg. 125:10, 2001.

20. Ayalya C and Blackwell KE: Protein C defi-ciency in microvascular head and neck recon-struction. Laryngoscope. 109:259, 1999.

21. Peverill RE: Hormone therapy and venous thromboembolism. Best Pract Res Clin En-docrinol Metab. 17:149, 2003.

22. Polancyk CA, Marcantonio E, Goldman L, et al: Impact of age on perioperative complica-tions and length of stay in patients undergoing noncardiac surgery. Ann Intern Med. 134:637, 2001.

23. Bhattacharyya N and Fried MP: Benchmarks for mortality, morbidity and length of stay for head and neck surgical procedures. Arch Otolaryngol Head Neck Surg. 127:127, 2001.

24. Shaari CM and Urken ML: Complications of head and neck surgery in the elderly. Ear Nose Throat J. 78:510, 1999.

25. Hidalgo DA and Jones CS: The role of emer-gent exploration in free tissue transfer: A review of 150 consecutive cases. Plast Recon-str Surg 86:592, 1990.

26. Kerrigan CL, Zelt, RG and Daniel RK: Sec-ondary critical ischemia time of experimental

skin flaps. Plast Reconstr Surg 74:522, 1984.

27. May JW, Chait LA, Obrient BMc, et al: The no-reflow phenomenon in experimental free flaps. Plast Reconstr Surg 61:256, 1978.

28. Jones NF. Intraoperative and postoperative monitoring of microsurgical free tissue trans-fers. Clin Plast Surg. 19:783, 1992.

29. Achauer BM and Black KS: Transcutaneous oxygen and flaps. Plast Reconstr Surg. 74:721, 1984.

30. Dunn RM, Kaplan IB, Moncoll J, et al: Experimental and clinical use of pH moni-toring of free tissue transfers. Ann Plast Surg. 31:539, 1993.

31. Menick FJ: The pulse oximeter in free muscle flap surgery. “A microvascular surgeon’s sleep aid.” J Reconstr Microsurg. 4:331, 1998.

32. Harrison DH, Firling M and Mott G: Experi-ence in monitoring the circulation in free flap transfers. Plast Reconstr Surg. 68:543, 1981.

33. Goldberg S, Sepka RS, Perona BP, et al: Laser Doppler blood flow measurements of common cutaneous donor sites for reconstructive sur-gery. Plast Reconstr Surg. 85:581, 1990.

34. Yuen JC and Feng Z: Monitoring free flaps using laser doppler flowmeter: 5 year experi-ence. Plast Reconstr Surg. 105:55, 2000.

35. Zinberg EM, Wood MB and Brown ML: Vascularized bone transfer: Evaluation of vi-ability by postoperative bone scan. J Reconstr Microsurg. 2:13, 1985.

36. Rosenberg RD: Actions and interactions of antithrombin and heparin. N Engl J Med. 292:146, 1975.

37. Conrad MH and Adams WP: Pharmacologic optimization of microsurgery in the new mil-lennium. Plast Reconstr Surg 108:2008, 2001.


SROMS 5 VOLUME 12.4

DETIREHNI DERIUQCA

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degnolorPnoitazilibommi

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-itna/sevitpecartnoclarOsnegortse

nedieLVrotcaF airunitsycomoH

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ycneicifedIIXrotcaF emordnyscitorhpeN

aimehtycyloP esanigarapsa-L

sisotycobmorhT sutillemsetebaiD

aimenallecelkciS aimedipilrepyH

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TABLE 1: Hypercoagulable States

Pressure on the microvascular pedicle should be avoided at all times.

such as those for tracheostomies or oxygen tents can easily compress the vessels in the neck. Nursing orders can be written to avoid the use of such devices, but a sign over the patient’s bed should also be used to prevent other personnel from making an innocent mistake. Similarly,

kinking or undue tension on the vessels needs to be avoided, especially during the immediate postoperative period. The position of the neck that optimizes vessel geometry should be strictly maintained. This position can be sustained by using postoperative sedation with ventilatory support. A paralytic agent can also be added to

this pharmacologic management. Those who prefer not to sedate patients in the postoperative period must clearly explain to the patient the importance of maintaining neck position.

Hemodynamics should be maintained as close to normal limits as possible. Avoiding extreme hyper- or hypotension is crucial to pre-venting hematoma formation while maintaining perfusion of the flap. A balance in the oxygen carrying capacity of blood and blood viscosity must also be achieved. Although little scientific evidence exists, a hematocrit of 28% to 30% is generally accepted as the desired goal for the immediate postoperative period.

Flap monitoring protocols vary drastically between institutions. Although many modalities of monitoring flaps are currently available, the standard today is a clinical exam of the flap’s skin paddle. The parameters evaluated include color, capillary refill, flap turgor and warmth. The frequency of serial postoperative evaluations of flaps also varies by institution, from every one hour to once every four hours. The frequency is based on the fact that the time between the onset of a thrombotic event and its recognition may be critical to the flap’s salvage.25 In pig skin flaps, this critical time is 7 hours.26 After 8-12 hours it may not be possible to re-establish the flap’s circulation.27

Possibly the most commonly used ad-junct to the clinical exam is the pin-prick test. A 25-guage needle is used at the center of the skin paddle and the rapidity, color and amount of blood return is evaluated. A healthy flap will bleed bright red blood within 1-3 seconds. Rapid return of dark-colored blood, combined with an ecchymotic skin paddle, suggests venous insuf-



REFERENCES

1. Jemal A, Thomas A, Murray T, et al: Cancer Statistics 2002. CA Cancer J Clin. 52:23, 2002.

2. Wingo PA, Tong T and Bolden S: Cancer sta-tistics, 1995. CA Cancer J Clin. 45:8, 1995.

3. Carrel A: The operative technique of vascular anastomosis and transplantation of organs. Lyon Méd. 98:859, 1902.

4. Nylen CO: The microscope in aural surgery, its first use and later development. Acta Oto-laryngol Supple. 116: 226, 1954.

5. Jacobson JH and Suarez EL: Microsurgery in anastomosis of small vessels. Surg Forum. 11:243, 1960.

6. Buncke HT and Schulz WP: Total ear reim-plantation in the rabbit utilizing microminia-ture vascular anastomoses. Brit J Plast Surg. 19:15, 1966.

7. Seidenberg B, Rosenak SS, Hurwitt ES, et al: Immediate reconstruction of the cervical esophagus by a revascularized isolated jejunal segment. Ann Surg. 149:162, 1959.

8. McLean DH and Buncke HJ Jr: Autotransplant of omentum to a large scalp defect, with mi-crosurgical revascularization. Plast Reconstr Surg. 49:268, 1972.

9. Panje WR, Krause CJ, Bardach J, et al: Reconstruction of intraoral defects with the free groin flap. Arch Otolaryngol. 103:78, 1977.

10. Carlson ER and Marx RE: Part II. Mandibular reconstruction using cancellous cellular bone grafts. J Oral Maxillofac Surg. 54:889, 1996.

11. Khouri RK: Free flap surgery. The second decade. Clin Plast Surg. 19:757, 1992.

12. Brown MR, McCullough TM, Funk GF, et al: Resource utilization and patient morbidity in head and neck reconstruction. Laryngoscope 107:1028, 1997.

13. Shusterman MA, Kroll SS, Weber RS, et al: Intraoral soft tissue reconstruction after cancer ablation: A comparison of the pectoralis major flap and the free radial forearm flap. Am J Surg. 162:397, 1991.

14. Kroll SS, Reece GP, Miller MJ, et al: Com-parison of the rectus abdominus free flap with the pectoralis major myocutaneous flap for reconstructions in the head and neck. Am J Surg. 164:615, 1992.

15. Urken ML, Vickery C, Weinberg H, et al: The neurovascular radial forearm flap in head and neck reconstruction: a preliminary report. Laryngoscope. 100:161, 1990.


SROMS 6 VOLUME 12.4

After 8-12 hours it may not be possible to re-establish the flap’s circulation.

ficiency; and no blood return with a flap that is cool to the touch suggests arterial thrombosis. Although this widely used exam is subject to much inter-observer error, it can be a valuable aid to the clinical exam.

The next most commonly used modality in postoperative flap monitoring is the hand-held surface Doppler probe. The practical utilization of the Doppler probe is mainly for confirmation of arterial flow, but its ability to confirm venous outflow has been proposed.28 Observance of a change in the character of the “phases” of the Doppler signal may help the clinician identi-fy the impending failure of a flap. However, because thrombotic complications are usually venous in nature, the utility of this modality is severely limited. In addition, one must be aware that Doppler signals obtained at the anastomotic site may be unreliable due to the proximity of the carotid arteries.

Doppler signals obtained at the anastomotic site may be unreliable due to the proximity of the carotid arteries.

Finally, a few of the adjunctive modalities that have been studied most frequently with MFTT should be mentioned. These include tissue pO

2 monitoring,29 tissue pH,30 pulse oxim-

etry,31 photoplethysmography,32 and laser Dop-pler flowmeters.33,34 Each of these instruments have their own advantages and disadvantages but none have made their way into mainstream microsurgical monitoring. Technetium scanning within 5-7 days of surgery remains the ideal method of evaluating the perfusion of vascular-ized bone-containing flaps.35 However, discus-sion of these modalities is beyond the intent of this review.

Antiplatelet and antithrombotic pharmacotherapy

There is little agreement on the ideal phar-macologic agent for the prevention of thrombo-sis in microvascular surgery. Like many areas of

microvascular surgery, the many institutional variations reflect individual practitioner expe-rience or retrospective case studies.

Heparin

Although the thrombus in a microvascular anastomosis is highly dependent on platelets, the “glue” that holds the large clumps of platelets together is fibrin. Therefore, the use of heparin to inhibit the formation of fibrin has logical merit in microvascular surgery. The heparin family of molecules acts by binding to and inducing a con-formational change in antithrombin III, changing antithrombin III from a slow inhibitor of coag-

ulation to a more rapid one. It is the inhibition of thrombin (factor IIa) and other factors in the coagulation cascade (XIIa, XIa, IXa, and Xa) that result in the anticoagulant effect seen with heparin.36 (See Selected Readings in Oral and Maxillofacial Surgery, Vol. 8, #6 )

An arterial thrombosis usually occurs in areas of high or disrupted flow or sites of athero-sclerotic plaque rupture. These thrombi consist mainly of platelet aggregates bound together by thin fibrin strands and are dependent on the action of platelets and the coagulation cascade. However, venous thrombi may be more reliant on the coagulation cascade because they form



Dr. David Kim comes to Shreveport from Baltimore, MD where he had spent two years in a fellowship with Dr. Robert Ord, concen-trating solely on head and neck oncology and reconstructive surgery. Prior to his fellowship,

Dr. Kim had completed his oral and maxil-lofacial surgery training at the Kings County

Hospital Center in Brooklyn, NY. His practice interests include head and neck tumor sur-

gery and primary microvascular reconstruc-tion as well as many more “traditional” oral and maxillofacial surgery procedures. These

include advanced dentoalveolar surgery, dental implants, bone grafting and preprosthetic

reconstruction, trauma, temporomandibular disorders, orthognathic and cosmetic surgery. Dr. Kim is actively involved in resident and medical student teaching at the university as well as community educational lectures

throughout the region. He also has an interest in clinical research and has published numer-

ous articles in peer reviewed journals. Dr. Kim also has clinical appointments in the area’s

community hospitals including Willis Knigh-ton and Schumpert medical centers.

Although currently single, Dr. Kim’s fiancée, Mary, is a plastic surgery fellow in New Jersey

and will be completing her training in 2005. Dr. Kim as settled in Shreveport and plans to have Mary join him upon completion of her

training.

Dr. G. E. Ghali has lived and practiced in Shreveport for the past 11 years. He is

recently married to his wife, Hope who is a native to this area. Dr. Ghali has arguably

the widest scope of any oral and maxil-lofacial surgery practice in the country,

spanning from cleft lip and palate repair to cosmetic surgery to head and neck cancer.

His professional interest lies especially with treatment of pediatric craniofacial defor-mities including craniosynostosis, cleft lip and palate, and dentofacial deformities.

However, his surgical interests also include dentoalveolar surgery, dental implants,

cosmetic surgery, head and neck oncology, bone grafting and preprosthetic surgery,

temporomandibular disorders and trauma.

Dr. Ghali is a full professor of surgery at Louisiana State University Health Science Center and is very active in resident and student education. He also has appoint-ments to countless hospital committees

helping to keep LSU-HSCS at the forefront of medical care in Louisiana. Dr. Ghali’s

association with national and international organizations has helped shape the profes-

sion of oral and maxillofacial surgery as well as provide world-wide recognition for the LSU-HSC Shreveport oral and maxillo-

facial surgery residency program.

Dr. Ghali has had numerous research interests including clinical and basic science

research. He has published in numerous peer-reviewed journals, has written many

book chapters and has edited textbooks that are vital to the knowledge base of many in

the specialty.


SROMS 7 VOLUME 12.4

in areas of blood stasis and consist mostly of red blood cells and fibrin rather than platelets.37 Furthermore, inhibition of the platelet aggre-gation pathway in rats does not improve vessel patency because fibrin alone can form a throm-bus without platelet aggregation.38 In the rats therapeutic levels of heparin more effectively prevented arterial and venous occlusion than antiplatelet agents.

In spite of these findings, the systemic use of heparin in microvascular surgery is generally limited to a few institutions or for the salvage of a threatened flap. This is probably due to fear of hemorrhagic complications such as hematoma

Dextran has been associated with noncardiogenic pulmonary edemaformation or donor site bleeding. Somewhat more commonly used is the intraoperative bolus of heparin (1000 U) usually given just before removal of the microvascular clamps. This was found to be beneficial in a rabbit model.39

The topical use of heparin as a local irri-gant in varying concentrations (between 50U/ml-250 U/ml) is also very common. Although low doses generally have no systemic effects, concentrations greater than 250 U/ml have been shown to alter the partial thromboplastin time. Although commonly used and advocated in some reviews,40 there is little research supporting its role as an effective topical antithrombotic agent.41

Aspirin

Aspirin (acetylsalicylic acid) has been available for more than 100 years and has prov-en to be an effective preventive medication in myocardial infarction, stroke or other occlusive vascular events. Aspirin acetylates cyclooxy-

genase and inhibits the production of arachi-donic acid metabolites, including thromboxane and prostacyclin. Thromboxane A2 is a potent vasoconstrictor and platelet-activating agent produced by platelet cyclooxygenase. Prosta-cyclin (prostaglandin I2), on the other hand, is derived from endothelial cyclooxygenase and is a potent vasodilator and inhibitor of platelet ag-gregation.37 Low doses of aspirin (1-5mg/kg) are theorized to preferentially inhibit thromboxane but not prostacyclin production.42 It remains a popular pharmacologic agent for prevention of thrombus formation, although its usefulness in microvascular surgery is somewhat suspect. In an animal model, low-dose aspirin inhibited ve-

nous thrombosis and improved microcirculatory perfusion.43 It is generally given immediately postoperatively, either orally or via nasogastric tube after crushing. Although side effects are rare, bleeding, gastritis and renal failure are possible sequelae and should be considered carefully, especially in elderly patients.

Dextran

Dextran is a polysaccharide synthesized from sucrose by Leuconostoc mesenteroides that is usually used in its low-molecular-weight form (40,000 MW – Dextran 40). In spite of recently reported complications,44 it remains popular among microvascular surgeons. Its mechanism of action is not completely understood, but pro-posed actions of dextran include: 1) increasing electronegativity of platelets and endothelium, resulting in decreased platelet aggregation; 2) increasing fibrin degradation by modifying its structure; 3) inhibition of alpha-2 antiplasmin with subsequent plasminogen activation; 4) decreasing amounts of factor VIII and von Wille-



At this stage, the cut ascending branch is followed through the transversus abdominis until the DCIA and DCIV are encountered. These vessels can then be followed down to their origins from the external iliacs. Laterally, the transversus abdominis is transected, leaving the same 2 cm cuff attached to the medial ilium as the other layers of the abdominal wall. This will allow exposure of the lateral femoral cutaneous

Care must be taken to avoid injury to the external iliac vessels and the femoral nerve when placing deep sutures.nerve and the iliacus muscle. The iliacus is then incised to expose the ilium at the desired point. Remember that the DCIA and DCIV run in the groove between the iliacus and the transverses abdominis, so a 2 cm cuff of iliacus should remain attached to the ilium to help preserve the pedicle.

At this stage, the inferior portion of the skin paddle can be incised. The incision is made through skin, subcutaneous tissue and through the tensor fascia lata and the tendon of the gluteus medius; exposing the lateral ilium in a subperiosteal plane for performance of osteot-omies. These osteotomies are performed from the lateral border while protecting the vascular pedicle medially. The DCIA and DCIV are then transected at their origins with double ligations.

Proper wound closure is very important to prevent hernia formation. The transversus abdo-minus and the internal oblique are approximated to the iliacus muscle with 2-0 Vicryl® sutures. Care must be taken to avoid injury to the external iliac vessels and the femoral nerve when placing deep sutures. A second layer of muscular wall closure approximates the external oblique, ten-sor fascia lata and the gluteus medius. Suction drains should be utilized between layers before finally closing the skin with staples.

The lateral border of the ilium should be exposed in the subperiosteal plane and fixated to the reconstruction plate with monocortical screws. The skin paddle can be used for oral lining or inverted to provide external skin cov-erage. If the internal oblique muscle is included in the flap, multiple mucosal or skin surfaces can be relined with this highly mobile portion of the

flap. Any required osteotomies should be done with care by limited dissection of the medial periosteum and protection of the pedicle. Any large gaps between osteotomies should be filled with free cortico-cancellous bone chips.

CONCLUSION

The philosophy of reconstructive surgery has undergone drastic changes within the last 30 years. With further understanding and excellent anatomic studies on the angiosome patterns of the human body, reconstructive surgeons have devised pedicled flaps to supplant the random pattern flaps of yesteryear. Now, with refine-ments of microvascular techniques and improved instrumentation, free tissue transfer–a procedure once thought to be high risk and radical–is now the reconstructive modality of choice for many head and neck reconstructions. Although not foolproof and certainly not indicated for every case of head and neck reconstruction, the con-sequences of aggressive ablative surgery of the head and neck can many times be tempered by the appropriate selection of donor tissue trans-planted with microvascular techniques.

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SROMS 8 VOLUME 12.4

brand factor; and 5) altering rheologic properties of blood by acting as a volume expander.37

Dextran has a potential antigenicity and a test dose of 20 ml is recommended prior to continuous infusion.45 The infusion is generally given at a rate of 25 cc-50 cc per hour for 5 days postoperatively, and it can be initiated imme-diately preoperatively, just prior to release of microvascular clamps, or immediately postoper-

“Under the microscope” every anastomosis is nearly identical.atively. It is discontinued after five days without tapering, and its effects can persist for several hours or days after discontinuation.41

Some controversy exists regarding the benefit of dextran to microvascular anastomoses. Retrospective reviews and anecdotal evidence suggest a favorable microvascular patency rate with dextran.46 This combined with its generally low side-effect profile contributes to dextran’s popularity as an adjunct to microvascular sur-gery. Dextran has been associated with noncar-diogenic pulmonary edema,47 thus vigilance of for signs and symptoms of this rare complication should be practiced. A loose association between dextran use and systemic postoperative compli-cations (myocardial infarction, congestive heart failure, pulmonary edema, pleural effusion, and pneumonia) has also been suggested.44 Whether these associations have a direct causal relation-ship remains to be elucidated.

Streptokinase, Urokinase, and Tissue Plasminogen Activator (t-PA)

These three fibrinolytic agents may be effective in the salvage of a thrombosed flap

when infused locally. However, evidence sug-gests a high rate of re-thrombosis when they are stopped. Heparin can be added to the sal-vage protocol of a thrombosed flap to prevent reocclusion.

Other pharmacotherapeutics that may have a place in future microvascular surgery include a recombinant form of hirudin that is secreted by leeches,48 tissue factor pathway inhibitor,49 clopidogrel (Plavix®), and glycoprotein IIb-IIIa

inhibitors.50 However, these agents require fur-ther clinical and experimental experience before their use can be advocated.

MICROVASCULAR TECHNIQUES

Reconstructive surgery in the head and neck is dissimilar to that in other regions of the body. Complex three-dimensional anatomic recipient sites provide a true challenge when designing flaps for this area. However, the mi-crovascular portion of these operations is very much the same. Other than some minor variables of patient positioning, recipient vessel selection, and vessel diameter; “under the microscope” every anastomosis is nearly identical.

At minimum, the specialized surgical instruments include, paired jeweler’s forceps, non-locking micro-needle drivers, adventitia scissors, and microvascular clamps (Fig. 1). Nylon suture especially designed for micro-vascular surgery is necessary. Usually 9-0 or 10-0 sutures are used, depending on surgeon’s preference, with a taper-cutting needle. Spatula shaped, tapered or reverse cutting needles are also available. Of course, an operating micro-scope designed for assisted microsurgery is also



The ilium is well suited for reconstruction of nearly all but the largest mandib-ular defects.

posterior to the ASIS.84 (Fig. 25B) The femoral nerve is situated deep to the DCIA just lateral to its branching from the external iliac artery, and the lateral femoral cutaneous nerve travels medial to the ASIS and may run superficial or deep to the DCIA.

Before creating the flap, the femoral ves-sels are palpated and identified at the inguinal ligament. The branching points of the DCIA

Figure 25. The anatomy of the deep circumflex iliac artery. A. Diagram of branching pattern of the DCIA and DCIV from the external iliac artery and vein, respectively; B. Diagram of branching of the DCIA showing musculocutaneous per-forators and endosteal supply to the ilium.

A. B.

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and DCIV are approximated just above the inguinal ligament and medial to the ASIS. A fusiform skin paddle is marked along an axis extending from the ASIS to the inferior border of the scapula. The skin paddle should be large enough to capture the cutaneous perforators just medial to the ilium.

The incision is begun at the superior border of the skin paddle extending medially toward the iliac vessels. This incision is carried through skin and subcutaneous tissue to the external abdominal oblique muscle. The external oblique muscle is then incised to reveal the internal abdominal oblique muscle, but it must be left attached to the ilium for about 2 cm to preserve the cutaneous perforators. The internal oblique is then also incised leaving 2 cm attached to

the inner ilium. This will reveal the ascending branch of the DCIA, which can be ligated. An alternative harvesting technique (described in detail by Urken84) harvests the internal oblique in its entirety with preservation of the ascending branch.


SROMS 9 VOLUME 12.4

Figure 1. Microvascular instruments commonly used in routine flap anastomoses. From left to right: Adventitia micro-scis-sors (three sizes); Long and short jeweler’s forceps, with and without tying platforms; Curved jeweler forceps (tying forceps); Micro-needle driver.________________________________________________________________________________

necessary, although high powered, wide-field loupe magnification may be used in some larger caliber anastomoses.

Recipient Vessel Selection

Due to the abundance of vessels in the head and neck, the availability of recipient vessels for microvascular anastomosis is usually not an issue. The choice of recipient vessels depends upon many factors, including vessel diameter, pedicle length, pedicle geometry, presence of atherosclerotic plaques, and evidence of traumat-ic dissection. If a neck dissection is performed prior to MFTT, the type of dissection will determine the presence of remaining vascular structures. (See Selected Readings in Oral and Maxillofacial Surgery, Vol. 6, #2) Effective com-munication between reconstructive and ablative surgical teams is crucial to maximize the preser-vation of neck vasculature while maintaining an oncologically sound neck dissection. Although some reconstructive surgeons insist upon evalu-ating the completed neck dissection for available recipient vessels, this can be greatly minimized

or eliminated with clear communication and a comfortable working relationship between the two teams. It would be an extremely rare instance where at least some option for micro-vascular anastomosis is not available, even in the most aggressive ablative procedure.

Recipient Arteries

Probably the most common recipient neck artery for MFTT is the facial. This branch of the external carotid artery is commonly transected during neck dissection as it traverses the infe-rior border of the mandible or as it enters the submandibular triangle. A length of the facial artery can often be preserved if the submandib-ular triangle is not grossly involved with tumor, and the submandibular gland can be separated from the facial artery without excessively trau-matizing the artery. Alternatively, the stump of the artery can be traced back to its origin from the external carotid and brought out from behind the posterior belly of the digastric and stylohyoid muscles to increase available length.



The ICOF is based on the deep circum-flex iliac artery and vein (DCIA and DCIV) as described by Taylor’s dye injection studies in 1979.82 Prior to that study, vascularized iliac crest bone was harvested with the superficial circumflex iliac artery, ascending branch of the lateral circumflex artery and the superior branch of the superior gluteal artery. Along with skin and bone, the flap can include the internal abdominal oblique muscle based on the ascending branch of the DCIA as described by Ramasastry et al.83 This allows the flexibility of a thin, mobile soft tissue component along with the relatively immobile cutaneous and osseous

If closure is too tight, a posterior compartment syndrome can occur.

Figure 23. Fibula harvested with skin paddle.Figure 24. Radiograph of fibula flap after closing

osteotomies to recreate mandibular contour.

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constituents of the flap.

Probably the greatest advantage of DCIA based flaps is the quality and quantity of the bone that can be harvested. The ilium is well suited for reconstruction of nearly all but the largest mandibular defects. It is probably best suited for defects (up to 16 cm) of the mandibular ramus and body because of its natural curvature and the ease of designing patterns to reconstruct the mandibular angle without osteotomies. To recre-ate the symphysis of the mandible, osteotomies

can be performed if the medial periosteum and vascular pedicle are preserved.

However, there are several disadvantages to the ICOF flaps. First is the possibility of weakness and hernia of the abdominal wall. Although rarely occurring, it is not difficult to imagine the potential effects of harvesting the internal oblique muscle.84 Second, utilization of full thickness ilium makes stripping of the lateral thigh musculature necessary, and the occurrence of postoperative gait disturbances may cause patient dissatisfaction.

The DCIA originates from the external iliac artery approximately 1 cm to 2 cm above the inguinal ligament. The artery travels laterally toward the anterior superior iliac spine (ASIS) and travels along the medial surface of the ilium in a groove formed by the junction of the trans-versalis fascia and the iliacus muscle approxi-mately 0.4 cm to 2.2 cm inferior to the iliac crest (Fig. 25A). The ascending branch to the internal oblique is given off variably along this course and terminates within the muscle serving with-out supplying cutaneous perforators. Perforators to the ilium as well as skin perforators are given off throughout the DCIA’s course. The DCIA terminates as a dominant skin artery about 10 cm



It would be an extremely rare instance where at least some option for micro-vascular anastomosis is not available.

Another commonly utilized branch of the external carotid is the superior thyroid artery. The caliber of this vessel is often adequate for only a short distance from its origin at the external carotid. Alternatively, end to side or even end to end anastomosis directly to the external carotid can be performed if no other adequate recipient artery is available.

The transverse cervical artery, from the thy-rocervical trunk, can be preserved in most neck dissections and quite substantial lengths can be obtained by tracing the artery’s path across the neck to the under-surface of the trapezius mus-

cle. This artery may be less prone to atheroscle-rosis than the branches of the external carotid, but it has a greater susceptibility to vasospasm. However, up to 20% of transverse cervical ar-teries arise directly from the subclavian artery and run a tortuous course through the brachial plexus. Under such conditions its utilization as a recipient vessel is difficult.50

Recipient Veins

Recipient veins in the neck include the internal and external jugular veins, a stump of the facial or common facial veins, and the trans-verse cervical vein. As with arterial preservation, the type of neck dissection, the proximity and stage of nodal disease, the skill of the ablative surgeon and communication between surgical teams will determine which vessels can be pre-served. Venous dissection should be performed with great care because careless dissection can result in apparently intact veins having intimal damage that will promote thrombus formation.

The anterior jugular veins are an option for venous anastomosis only where a tracheostomy will not be utilized. Unfortunately, many head and neck cancer patients will have a tracheosto-my at least temporarily, and the caudal portion of these veins runs in close proximity to the stoma, increasing the risk of thrombosis due to tracheal contamination.

When no recipient veins are available in the neck, the cephalic vein can be mobilized from the upper arm as described by Urken.51 The vein can be harvested as an interpositional vein graft or as a direct outflow recipient. Of course,

this option is a last resort after ipsilateral and contralateral recipient neck veins are deemed unsuitable. More common sites for vein grafting are the greater and lesser saphenous veins of the lower extremities. These veins are not difficult to harvest and have an adequate and constant caliber throughout most of their length. Howev-er, higher rates of flap failure have been shown with vein grafts.52

Creating Vascular Anastomoses

Prior to vascular anastomosis, the flap should be inset to the defect and any tunneling necessary for the passage of the pedicle should be performed. For oral cavity reconstruction, a watertight closure of the flap to the oral mucosa must be obtained to prevent the catastrophic complication of a salivary leak and fistula for-mation. Salivary contamination of the vascular anastomosis will result in thrombosis. We prefer Vicryl® sutures passed in an interrupted hori-zontal mattress fashion, allowing wound edge eversion and a very tight seal. Once the inset is complete or nearly complete, attention can



Figure 22. Skin markings prior to fibula flap harvest.

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the interosseous membrane. The initial incision is extended proximally and distally to facilitate this dissection.

The fibula can then be osteotomized to allow the completion of the dissection. Subperi-osteal dissection occurs at both the proximal and distal ends circumferentially around the fibula to protect the vascular pedicle. Oscillating, re-ciprocating or Gigli saws may be used for the osteotomies. Once the osteotomies are complete, the distal portions of the peroneal artery and vein can be identified, ligated and divided. Next, the posterior portion of the skin paddle is incised down through the fascia overlying the soleus and gastrocnemius muscles. If septocutaneous perforators are present, a cuff of soleus may not be needed with the posterior crural septum to ensure adequate vascularity to the skin paddle.

With the fibula distracted, the medial dissection of the flap proceeds by dividing the interosseous septum, revealing the chevron shaped tibialis posterior muscle. The perone-al artery and venae comitantes are followed through this muscle, carefully ligating branches with hemo-clips until the branching of the poste-rior tibial artery is identified. The flexor hallicus

longus should then be transected and the tourni-quet released. Allow the leg to re- perfuse for a period of at least 20 minutes prior to final flap harvest. During this time, capillary refill, pulses and warmth of the foot should be evaluated.

After harvesting (Fig. 23), the flap is trans-ported to the recipient site and contoured to its desired shape by creating closing osteotomies and discarding unnecessary bone as previously described (Fig. 24). The pedicle should be fash-ioned on the lingual side to facilitate rigid fixa-tion of the flap to the reconstruction plate with monocortical screws. The skin paddle is inset in the standard fashion after bony contouring and fixation is complete. The skin paddle should be transposed over the lateral surface of the fibula, covering the reconstruction plate to provide some protection from exposure. The artery and venae comitantes are a good size match to most of the maxillofacial vessels indicated previously, although their close association limits recipient choices to arteries and veins near one another.

The donor site is managed by obtaining adequate hemostasis, light reapproximation of the muscles to decrease dead space, and placement of two, large caliber (19 French Blake®) suction drains at different tissue levels. The cutaneous defect can be undermined and primarily closed but if closure is too tight, a posterior compartment syndrome can occur. A split thickness skin graft will take nicely on the vascular bed of the muscle. A posterior splint is fabricated to support the ankle in a dorsiflexed position and the patient is told to not put weight on the leg for seven days. After that period light physical rehabilitation may begin.

Iliac Crest Osteocutaneous Flap (ICOF)



Careless dissection can result in apparently intact veins having intimal damage that will promote thrombus formation.

Salivary contamination of the vascular anastomosis will result in thrombosis.

then be turned to preparing both the recipient and donor vessels.

Regardless of the vessel type or the anas-tomosis technique being performed, the initial preparation of all donor and recipient vessels is essentially the same. Extreme care should be employed when dissecting the vessels to be

utilized. At no time should the vessel wall be grasped directly with any instrument. The only part of the vessel that should be handled is the adventitia.

The recipient vessels are prepared by 360° dissections under magnification for an ample distance to allow manipulation of the vessel during suturing of both front and back walls. A vessel length of 3 cm - 4 cm should be adequate for this purpose in most cases. All branches should be meticulously clipped, but the anastomosis site should be relatively devoid of clips that might interfere with suturing. Small,

non-crushing microvascular clamps are used to occlude blood flow proximally in both recipient arteries and veins (Fig. 2).

End-to-end anastomosis (EEA)

The type of microvascular anastomosis will depend on many factors, including pedicle length, vessel size match, availability of recipi-ent vessels and surgeon’s preference. The EEA is probably the simplest anastomosis concept, i.e., the sharply cut end of the donor vessel is sutured to the cut end of the recipient vessel. Ma- Figure 2. Left. Double (approximating) and, Right. Single

disposable microvascular clamps.

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jor variations of the EEA technique involve the pattern of suture placement at the anastomosis. Whichever scheme one chooses, the principle of placing six to ten sutures around the circumfer-ence of the vessel, perpendicular to its cut end should be strictly followed.

Alexis Carrel’s original description of the EEA for macrovascular anastomosis involved placing two sutures between 120°-150° apart, followed by a third suture in a position to com-plete an isosceles triangle (Fig. 3).3 Additional sutures are then placed between the initial three sutures until the anastomosis is complete. This technique was suggested as a way to decrease the chance of “back-wall” suturing, i.e., placing a suture through both the intended vessel wall and the opposite wall on the same vessel. Inadvertent back-wall suturing will effectively diminish the lumen of the vessel and lead to occlusion of the

anastomosis.

An alternative technique we more com-monly use is the halfway estimation technique. Suturing of the vessel ends is begun by placing



have shown that a substantial percentage of fibu-la flap candidates, when imaged preoperatively, have a significant problem that may require alteration of the reconstructive plan (Fig. 21).80

The presence of a septocutaneous or mus-culocutaneous perforator to supply the attached skin paddle in a FOCF should be identified during the initial stages of the dissection. If no perforator is seen, a different soft tissue flap option should be pursued. The overall reliabil-ity of the fibular skin paddle is reported to be between 90% and 100%. Skin paddles should be centered on the junction of the middle and distal thirds of the fibula with a relatively long axial dimension to increase the likelihood of

Figure 21. Preoperative lower extremity angiogram for a potential free fibula flap reconstruction. Note poor filling of mid-calf anterior tibial arteries bilaterally. This patient had no symptoms of peripheral vascular disease. A different reconstructive plan was formulated due to less than ideal vascular supply to the feet.

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capturing these perforators.

Damage to the common peroneal nerve can lead to an equinovarus deformity of the foot along with anesthesia to the anterior and lateral lower leg and dorsum of the foot. This can be avoided by preserving the proximal 6 cm to 7 cm of fibula and avoiding excessive traction during dissection of the proximal pedicle. Damage to the deep peroneal nerve or scarring of the flexor hallicus longus may result in weakness in dorsi-flexion of the foot. However, any difficulty with ambulation usually resolves within a few months if no neural injury is present.

Landmarks for harvesting the FOCF include the lateral epicondyle of the ankle and the fibular head. A line between these two points approximates the location of the posterior crural septum. The segments of fibula to be preserved at the joints are marked and an appropriately sized skin paddle is drawn, centered on the posterior crural septum and the middle and distal thirds of the fibula (Fig. 22). The patient’s lower extremity is prepped circumferentially from toes to hip and a large pneumatic tourniquet is placed on the thigh and inflated to 350 mm Hg.

As described by Fleming et al,81 the dissec-tion begins by incising the skin of the anterior portion of the skin paddle through subcutaneous tissue and fascia overlying the peroneus longus muscle. Dissection proceeds posteriorly in the subfascial plane until the posterior crural septum is encountered. Here, septocutaneous or mus-clulocutaneous perforators should be visible. The posterior crural septum is followed to the fibula, and dissection along the anterior portion of the fibula is performed, and the anterior tibial vessels are identified. Staying close to the fibula, the medial dissection is continued to identify



Figure 3. The “Carrel Method” for end-to-end vessel anastomosis. Note initial sutures are placed in an isosceles triangle arrangement to reduce the risk of “back-wall” suturing.

Figure 4. The halfway estimation technique for end-to-end vascular anastomosis. See text for more details.

Figure 5. Forceps gently being inserted into the lumen of the vessel to facilitate suture passage. Figure 6. Passage of the suture through the opposing

vessel end.

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lacking.73 Celik et al. regard many of these reports to result from a lack of recognition of small perforators or due to the surgeon’s inability to trace musculocutaneous perforators through the vastus lateralis.74 Because of these anatomi-cal variations, some authors recommend that the reconstructive surgeon be prepared to convert from an ALTF to an anteromedial thigh flap or a tensor fascia lata flap.72

Composite Bone-containing Flaps

Fibula Osteo-cutaneous Flap (FOCF)

Although the fibula flap was first described by Taylor in 1975 for lower extremity reconstruc-tion,75 it was Hidalgo in 1989 that introduced the fibula osteo-cutaneous flap (FOCF) for mandib-ular reconstruction.76 Now it is the most com-monly utilized microvascular bone-containing flap for mandibular reconstruction. Factors that encouraged its widespread use include relative ease of harvest, low morbidity profile, the long distance between donor and recipient sites to facilitate two-team approaches, and the ability to contour the bone to the required shape.

The fibula is a non-weight bearing bone with an average of 22 cm to 25 cm of bone available for harvest. Based on the peroneal artery and venae comitantes, the fibula flap can be transferred as a bone-only flap or as an osteocutaneous flap with the skin of the lateral calf perfused by cutaneous perforators traveling through or along the posterior crural septum. The entire length of fibula can be obtained except for 6 cm to 7 cm at its proximal and distal ends to preserve the integrity of the knee and ankle joints. The length of the vascular pedicle that

can be harvested is limited by the location of the bifurcation of the posterior tibial artery. However, proximal fibular bone not necessary for reconstruction can be discarded after careful subperiosteal dissection to increase the effective pedicle length.

The tubular fibular bone must be contoured for most mandibular or maxillary reconstruc-tions. These contours can be created by care-ful subperiosteal dissection circumferentially around the osteotomy site while carefully pro-tecting the vascular pedicle during bone cuts. These “closing osteotomies” allow for a rough approximation of the fibula to the normal con-tour of the mandible.

Prior to harvesting of the FOCF the per-fusion of the foot should be evaluated in some manner. Because many patients with head and neck cancer also have risk factors for periph-eral vascular disease, compromised perfusion to the foot after flap harvesting is a possibility. Also, the presence of a peroneal artery magna variation or two-vessel flow to the distal lower extremity may also place the foot at risk for post-

operative ischemia. Angiography has been the standard imaging modality for the preoperative assessment of the lower extremities. However, magnetic resonance angiography (MRA),77 and recently CT angiography78 have been shown, in some centers, to provide adequate information; although both are very technique and equipment sensitive. Some surgeons believe that preop-erative assessment is unnecessary and rely on clinical evaluation of the anterior and posterior tibial vessels during flap elevation to estimate the quality of flow to the distal extremity.79 Others



Figure 7. Sutures are tied with an initial surgeon’s knot and at least two additional throws.

Figure 8. Arrow points to the position of the second suture approximately 180° from the first.

two sutures approximately 180° or more from each other (Fig. 4). The third suture is placed at a point halfway between the first two. The remaining vessel circumference between the first two sutures is then halved by each additional suture (sutures 4 & 5) until that side is complete. Once completed, the clamps are flipped and a similar procedure is performed for sutures 6 through 8 on the back side. The most difficult sutures in this and most techniques are the initial “anchoring” sutures.

To facilitate suture passage the tips of jeweler’s forceps can be placed gently into the lumen of the vessel and slightly opened to place slight tension on the vessel wall (Fig. 5). The opposite vessel end is grasped by the adventitia and the needle can be passed at the correspond-ing position as the initial needle passage (Fig. 6). The sutures are tied with a surgeon’s knot with at least two additional throws (Fig. 7). The second suture is placed in a similar fash-ion approximately 180° from the first (Fig. 8). Remember, the vessel should never be grasped ____________________________________



septum between these muscles or travel through part of the vastus lateralis.70 The cutaneous per-forators to the lateral thigh may also branch from the transverse branch of the lateral circumflex femoral artery or directly from the deep femoral artery.71 This variation in vascular anatomy and the somewhat inconsistent location of cutane-ous perforators has impeded this flap’s overall acceptance for head and neck reconstruction.

No special preoperative evaluation is needed prior to flap harvesting. Doppler probe localization of the cutaneous perforators can be performed but may not be accurate. The maxi-mum area that this flap can support is reported up to 800 cm2, consisting of skin from the level of the greater trochanter of the femur to a line 3 cm above the patella.70

Drawing a line from the anterior-superior iliac spine to the superolateral corner of the patella identifies the dominant perforator to the lateral thigh skin. The midpoint of this line is marked, and a 3 cm radius circle is drawn. The majority of the cutaneous perforators will be lo-cated in the inferolateral quadrant of this circle, and the flap’s skin paddle should be designed to center on this area (Fig. 20).

Flap harvesting begins by incising skin and subcutaneous tissue on the medial surface of the skin paddle. This dissection continues down to the tensor fascia lata. Depending on the thickness of tissue needed, the flap may or may not include the tensor fascia lata. In either case, the skin paddle is gently dissected laterally until the cutaneous perforators are identified. These perforators are followed either through the inter-muscular septum between the rectus femoris and vastus lateralis (in the case of septocutaneous perforators) or through the vastus lateralis (in

the case of musculocutaneous perforators). If dissection through the vastus lateralis is neces-sary, careful ligation of muscular branches must be performed. Dissection is continued until the source vessel (descending branch of the lateral circumflex femoral) is identified which can also be dissected for any desired length up to 16 cm.72

One great advantage of this flap is the pos-sibility of harvesting a very thin flap (as little as 5 mm of thickness) while maintaining the supra-fascial vascular plexus based on the perforating vessels. Care must be taken when dissecting the source artery and vein to avoid injury to the nerve to the vastus lateralis. If intramuscular dissection was necessary the muscle should be reapproximated after adequate hemostasis is achieved. The wound edges can often be pri-marily closed with wide undermining when the skin paddle dimensions remain under 6 cm to 9 cm. Larger defects may require skin grafting.

A possible disadvantage to this flap is the inconsistent location and size of the cutaneous perforators. Rarely perforators may be totally

Figure 20. Design of the skin paddle for the anterolateral thigh flap based on landmarks described by Song et al.70

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by any instrument, and only the adventitia should be used to manipulate the vessel.

Similar techniques can be utilized for ve-nous anastomosis, however, the vessels walls are much thinner and more susceptible to damage from aggressive traction, dissection or other manipulations. Smaller, more controlled move-ments are necessary to avoid damaging veins when these techniques are employed.

Remember, the vessel should never be grasped by any instrument,

Figure 9. Heparinized saline solution can be used to open the vessel lumen to help prevent “back-wall” suturing. This maneuver is especially useful when performing venous anastomoses.

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Another potential pitfall of venous anas-tomosis is a higher likelihood of “back-wall” suturing. The placing of jeweler’s forceps into the lumen of the vessel to facilitate needle pas-sage helps to avoid this error. Alternatively, a skilled assistant can help prevent “back-wall” suturing by applying a gentle stream of heparin-ized saline irrigation to the vessel lumen allow-ing it to balloon while placing the sutures (Fig. 9). However, this technique creates a change in the optics of the procedure because the surgeon must visualize the vessel through a pool of fluid that decreases depth perception and may affect the accuracy of needle placement.

End-to-side anastomosis (ESA)

The ESA is applied in situations where properly sized recipient vessels are unavailable, or the flow pattern of the selected recipient ves-sel must be maintained rather than sacrificing it for the sole purpose of supplying the flap. Although technically somewhat more difficult, the ESA is a reliable microvascular technique, and due to the elasticity of the vascular walls, has a tendency to tent the anastomosis open. The most common ESA performed clinically in head and neck reconstruction is for venous

outflow of a donor vein to the internal jugular vein. In fact, it is the preferred method of venous anastomosis of some authors.53-55 However, one study showed that the incidence of internal jug-ular vein thrombosis on the first postoperative day is 24.7% after modified neck dissections, with obvious consequences to venous outflow.56

To create the ESA the donor vessel is clamped with a single micro-clamp some dis-tance proximal to its cut end. The recipient ves-sel should be dissected circumferentially for an

adequate length to allow manipulation. When the recipient is the internal jugular vein, care must be taken to avoid damage to not only the vein itself, but also the vagus nerve and carotid artery. Any branches should be meticulously clipped prior to transection. For a large vessel, such as the internal jugular, the use of micro-clamps may not be possible, but vessel loops may be utilized at either end of the proposed ESA to temporarily



With perforator flaps, the skin territory to be harvested is dissected directly with the skin perforator through intervening tissue to the source vessel.

semilunaris to preserve the musculocutaneous perforators present over the muscle. Similarly, the medial portion of the skin paddle is incised and undermined deep to Scarpa’s fascia until the linea alba is recognized and the rectus sheath is incised at its medial margin.

A vertical incision from the inferior portion of the skin paddle oriented toward the femoral vessels is made down to the rectus sheath. The rectus sheath is then incised at the midpoint of the muscle to expose the rectus muscle. Once the entire caudal portion of the muscle is in view, the dissection continues by elevating the muscle off the posterior rectus sheath using blunt dis-section. The mixed motor/sensory branches of

the intercostal nerves will be encountered at this point. Also on the undersurface of the muscle, the DIEA and DIEV will come into view. The nerves can be transected and the vascular ped-icle followed inferiorly until the desired length of pedicle is achieved. Two tributaries of the DIEV join to form a single vein just before it’s branching from the external iliac vein.

Closure begins with reapproximation of the inferior portion of the cut anterior wall of the rectus sheath. The superior portion, which was harvested with the flap, may also be closed with relatively large, slowly resorbable sutures. Care should be taken not to puncture the posterior rectus sheath with suture needles or other sharp instruments that could produce visceral injury. Primary skin closure generally can be achieved with undermining.

Anterolateral Thigh Flap (ALTF)

Recently, our knowledge of the path of the cutaneous blood supply from underlying source vessels has had a dramatic increase. The angiosome theory indicates that the human body is composed of approximately 40 blocks of composite tissue, each with its own cutaneous territory supplied by a discrete source vessel.68 Simply stated, all arteries to the skin either travel directly to their destination (direct perforators) or first travel through some other tissue, usually muscle (indirect perforators).69 The use of the ALTF, which was pioneered in Asia, has recently popularized the use of perforator flaps.

The borrowing of composite tissue from one site to rebuild another is the basis for

reconstructive surgery, but one of the foremost concerns of free flap planning is donor site morbidity. Although many of the aforemen-tioned free flaps have very reasonable morbidity profiles, a new standard may be developing for acceptable donor site morbidity in free flap reconstruction. With perforator flaps, the skin territory to be harvested is dissected directly with the skin perforator through intervening tissue to the source vessel. For example, the deep inferior epigastric perforator flap avoids the morbidity of harvesting the rectus muscle with skin, along with its attendant sequelae.

The ALTF is based on the cutaneous per-forators of the descending branch of the lateral circumflex femoral artery, a branch of the pro-funda femoris. The pedicle travels between the rectus femoris and the vastus lateralis muscles along with the motor supply to the vastus latera-lis. The perforators may be in the intermuscular



occlude blood flow (Fig. 10). Alternatively, a baby Satinsky vena cava clamp (Fig. 11) can be used atraumatically for this purpose.

A venotomy appropriate to the size of the lumen of the donor vessel is created either with scissors or a microscalpel. The venotomy should be slightly larger than the cut end of the donor vessel and in an elliptical or diamond shape. Two ends of the venotomy are sutured to the donor vessel leaving the needles attached to each suture (Fig. 12). The remaining sutures are then placed in a running fashion starting with the back wall. These sutures can be placed from inside the lu-men (Fig. 13). When completed, the end can be tied to the tail of the opposite “anchoring” suture. The same suturing technique is then performed on the front wall to complete the anastomosis. Alternatively, an interrupted suture technique may be performed on both walls (Fig. 14).

Figure 10. Use of vessel loops during end-to-side venous anastomosis.

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Figure 11. A baby Satinsky vena cava clamp.

Comparisons of the performance of EEA and ESA have not shown significant differenc-es. One study retrospectively compared EEA and ESA from over 2000 microvascular anas-tomoses and found no significant difference in failure rate of arterial or venous anastomoses.57 The ESA may be more appropriate for some flaps because it allows them to “draw” only as much blood as they need rather than becoming engorged with the terminal blood flow from an EEA.58 A recent study comparing anastomosis to the external jugular (EEA) versus directly to the internal jugular (ESA) or to its branches (EEA) showed a significantly higher failure rate with the external jugular vein.59 These authors concluded that the internal jugular system should be utilized whenever possible.

FLAP SALVAGE

The threatened flap must be identified as early as possible in order to maximize the possibility of salvaging the reconstruction. De-pending on the timing of the thrombotic event, return to the operating room may be necessary to surgically revise one or more of the microvas-cular anastomoses. Alternatively, non-surgical methods of salvage may be indicated if the event occurs in the late post-operative period.

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The anatomy of the anterior abdominal wall should be reviewed because preservation of the fascial sheaths is critical to preventing the formation of postoperative abdominal hernias. The rectus sheath extends from the pubis to the xiphoid and is formed by the fibrous aponeu-roses of the abdominal muscles. However, it is important to realize that the composition of the posterior wall of the sheath changes at the level of the anterior superior iliac spine, demarcated by the arcuate line (Fig. 19). Above the arcuate line, the posterior rectus sheath is formed by extensions of the transversalis fascia and part of the internal oblique aponeurosis, and this double-layered sheath is adequate to prevent hernias. Below the arcuate line, the posterior rec-tus sheath is formed by the transversalis fascia alone. Therefore, below the arcuate line bulging or hernia complications may occur if the fascia is not reinforced by preserving the anterior sheath and closing it as a separate layer.

Because the skin paddle of the RAMF can be oriented in many different configurations, flap design and pedicle orientation should be per-formed with great care, especially in maxillary reconstruction, to ensure that surfaces are lined with the appropriate tissue and that the vascular pedicle reaches the recipient vessels in the neck.

One of the foremost concerns of free flap planning is donor site morbidity.

Figure 19. Aponeuroses forming the rectus sheath. Superior to the arcuate line the rectus sheath is com-plete posteriorly. Below the arcuate line the muscle contacts transversalis fascia.

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An oblique skin paddle crossing the abdominal wall obliquely from costal margin to just infe-rior and lateral to the umbilicus as described by Urken67 allows for a large skin paddle that is thin at the distal tip (near the scapula) and thicker proximally near the umbilicus. This allows the use of thick skin and subcutaneous fat in areas that require bulk, and thinner more pliable skin in other areas. It is also somewhat more flexible because much of the skin paddle is not directly

over the rectus abdominis muscle. Alternatively, vertical or (less commonly for head and neck defects) transverse skin paddles can also be used. The following description of flap harvesting is for the oblique skin paddle.

Flap elevation begins by incising the su-perior margin of the skin paddle through skin, subcutaneous tissue, fat and fascia to expose the

rectus muscle from the linea alba to the linea semilunaris. The inferior margin is then incised to the same level. Once the linea semilunaris is identified both superiorly and inferiorly, the lateral extent of the rectus muscle is defined, and the remainder of the skin paddle can be incised laterally down to subcutaneous fat. The skin can be undermined at the level of Scarpa’s fascia until the linea semilunaris is reached. The rectus sheath is then incised at the linea



Figure 12. Initial suture placement in end-to-side anas-tomosis (ESA).____________________________________

Figure 13. “Back-wall” sutures placed first from inside the lumen for ESA.

Figure 14. Interrupted suture technique for ESA._____________________________________

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Techniques for flap salvage are not well docu-mented. The specific procedures will depend on the clinical situation and the appearance of the anastomosed vessels.

For example, an expanding hematoma in the neck may compress the venous outflow of a flap, causing it to appear purple and edematous.

In this circumstance, the neck should be explored and the only necessary salvage procedure may be evacuation of the hematoma along with bipolar coagulation or clipping of any bleeding vessels so that venous outflow can be restored. Howev-er, in other instances both venous and arterial anastomoses must be opened and revised. In rat femoral veins, most venous thromboses occurred within 24 hours of anastomosis.60 In a clinical situation, this would equate to an early throm-bosis of the venous anastomosis that warrants immediate surgical exploration.

Once a thrombosed artery or vein is identi-fied, the length of the vessel should be palpated to determine the extent of the clot. At the site of the clot the thrombosis will be firm whereas the vessel will be compressible proximal and distal to the clot. If the thrombosis cannot be identified by palpation then a strip test can be performed by occluding the lumen of the vessel downstream, applying a stripping motion upstream and then releasing (Fig. 15). Rapid refill of the vessel usually indicates adequate flow.



Figure 18. A. Branching pattern of the abdominal wall vessels, B. Various orientations for the skin paddle in rectus abdo-minus myocutaneous flaps.________________________________________________________________________________

A. B.

The length of the pedicle is quite adequate, with good caliber vessels for microvascular anastomosis. The skin paddle can be designed in several different orientations to the rectus muscle for various applications (Fig. 18B).

Finally, the DIEA perforator flap allows for a much thinner skin paddle without harvesting the muscle.65 In this flap, the cutaneous perfo-rators to the para-umbilical skin are dissected through the rectus muscle to the DIEA and DIEV. This perforator flap shares the recent burst in popularity of other perforator flaps.

The rectus muscle receives its blood supply from both the deep superior epigastric artery

and vein (DSEA and DSEV) and the DIEA and DIEV; however, the latter have approximately twice the diameter of the former. In addition, the musculocutaneous perforators are directly associated with the DIEA and DIEV and only anastomose to the DSEA and DSEV through a series of small vessels where flow can be reversed. These dominant perforators to the anterior abdominal skin are concentrated around the umbilicus.66

The DIEA branches from the external iliac artery just superior to the inguinal ligament. It travels superiorly and medially to penetrate the transversalis fascia 3 cm - 4 cm caudal to the ar-cuate line on the underside of the rectus muscle.



If a thrombosis is present open the anasto-mosis by removing some or all of the sutures. The area of the thrombosis can either be resected and a new anastomosis attempted at the new site, or the thrombus can be removed using Fogarty® catheters. The choice of technique will depend on the clinical circumstance, length and caliber of vessel and quality of the existing vessel open-ing. For example, if the thrombosis occurred due to endothelial damage at the original site of anastomosis, that section of artery or vein should be removed and a new anastomosis created at an undamaged site.

Figure 15. The “strip test” performed to confirm venous flow across the anastomosis. (See text for more details.)

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Other situations that may require revision of microvascular anastomoses are kinking or compression of the vascular pedicle. Such com-pression can occur due to a hematoma or from external sources such as tracheal ties. These situations are best avoided entirely, but when they do occur their remedy is relatively straight-forward. A kinked vessel can be straightened by reorienting the pedicle and suspending it with carefully placed sutures. Alternatively, the anastomosis can be resected, the vessel trimmed and the anastomosis revised, or an alternative recipient vessel may be chosen to improve the pedicle’s geometry.

Exsanguination therapies must be dis-cussed as an option for those flaps whose venous anastomoses cannot be revised or whose revision has failed. These modalities maintain perfusion, allowing continued viability of tissue while neovascularization occurs. These therapies are known to be useful in finger replantations, but head and neck reconstruction requires the exan-guination of a much larger surface area of tissue, possibly leading to considerable blood loss and the need for a transfusion. Indeed, one paper reported that an average of 13 units of packed red blood cells per patient was necessary to maintain adequate hemoglobin concentrations.61 Medicinal leech therapy in head and neck MFTT should proceed with much care so the leeches do not migrate down the esophagus or larynx. Furthermore, antibiotic prophylaxis with an-ti-pseudomonal penicillin or a fluoroquinolone should be instituted prior to leech treatment to prevent infection by Aeromonas hydrophila.62

Some promising laboratory and clinical data have been published on the use of throm-bolytic agents such as streptokinase, urokinase or tissue-type plasminogen activator, but their



Figure 16. Completed dissection of radial vessels and cephalic vein (in vessel loop). Note two Allis clamps retracting brachioradialis muscle._____________________________________

placing the final dressing, perfusion to the index finger and thumb should be verified by checking capillary refill.

The flap should be inset, and the micro-vascular anastomosis carried out with alacrity to minimize ischemia time. The radial artery is usually a good size-match to many recipient arteries in the head and neck, including the facial, superior thyroid and transverse cervical. The cephalic vein is also of excellent caliber and can be matched to the external jugular or facial veins (Fig. 17). Thus, this flap has been described as a “macro-microvascular flap.”

The decision to utilize both the cephalic vein and the venae comitantes should be made on a case-by-case basis. Although the flap is well known to survive with drainage from either the superficial or deep venous systems, many authors will perform more than one venous anastomosis when adequate recipient veins are present. The superficial veins are usually chosen if only one venous anastomosis is to be performed, due to their larger caliber and thicker vessel walls.

Figure 17. Completed anastomosis of radial artery to facial artery and cephalic vein to facial vein.

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Rectus Abdominus Myocutaneous Flap (RAMF)

Based on the deep inferior epigastric artery and vein (DIEA and DIEV, respectively), (Fig. 18A) the RAMF has been a reliable and popular flap for many areas of reconstruction. The flap can transfer large amounts of skin, subcutane-ous tissue, muscle and fascia along with a fairly long vascular pedicle of good caliber. This flap is very well suited for defects that require large volumes of tissue, such as a total maxillectomy, total glossectomy, skull base or large scalp de-fects. Of course, pedicled and free flaps of the rectus muscle based on the superior or inferior epigastric arteries have been well described for breast reconstruction.

One advantage of the RAMF for head and neck reconstruction is the ability for two surgical teams to operate at the same time. However, this is advantage is somewhat overstated because two teams can be very crowded around a short patient. The very substantial volume of tissue provided allows filling of large areas. However, the patient’s body habitus determines the amount of tissue available, and the harvested volume will decrease over time due to the denervation of the muscle.



use is still quite limited.37 This may be due to the risk of bleeding with systemic exposure to these substances or possibly due to a fear that the thrombosis will return upon discontinuation of the drug.

SELECTED FLAPS

Soft Tissue Flaps

Radial Forearm Fasciocutaneous Flap (RFFF)

The radial forearm fasciocutaneous flap (RFFF) has become the “workhorse” microvas-cular flap for the head and neck. Since Soutar’s popularization of the flap in the 1980’s,63 the RFFF has become one of the most commonly utilized and reliable soft-tissue free flaps for head and neck reconstruction. Based on the radial artery, venae comitantes and cephalic vein, the flap can be transferred with bone (partial thickness radius), tendon (palmaris longus), muscle (brachioradialis), nerve (lateral ante-brachial cutaneous) as well as skin and fascia.

If necessary, the skin of nearly the entire forearm (from the flexor crease of the wrist to the antecubital fossa and nearly the entire circumference, except for a small strip on the ulnar aspect of the forearm) can be raised with the flap. The flap should be centered over the radial vessels and cephalic vein but the shape and overall dimensions can be tailored appropriately to the clinical situation. Bilobed, dual cutaneous paddles, fascia only, folded and tubed flaps have been designed and successfully utilized for different reconstructive needs. The skin of the volar forearm is generally quite thin and pli-able with varying densities of hair follicles, and males have somewhat thinner skin in this region than females. The thin and pliable skin makes

the radial forearm a nearly ideal donor site for reconstruction of areas that require thin, mobile tissue including the floor of mouth, tongue, and soft palate.

The blood supply to the lower arm and hand is by the radial and ulnar branches of the brachial artery. The radial artery terminates in the deep palmar arch and the ulnar leads to the superficial palmar arch. Once the radial forearm flap is har-vested, the blood supply to the hand and digits will be completely reliant on the ulnar artery. The blood supply to the third, fourth and fifth digits are normally supplied by the ulnar artery, so the perfusion to the thumb and index finger is at greatest risk when harvesting this flap.

In order for ischemia of the thumb or index finger to occur, two anatomic variations must be present. First, the superficial palmar arch must lack branches to the thumb and index finger. Second, the superficial and deep palmar arches must completely lack communicating branches. A cadaveric study showed this combination of anomalies to be present in approximately 12% of specimens.64 An accurate Allen’s test is essential for avoiding potential ischemic complications after flap harvest. If the Allen’s test is equivocal or difficult to interpret, radial artery mapping can objectively determine the pattern of flow and reversal of flow following occlusion of the radial artery.

Flap design and orientation should be per-formed with care because the three dimensional nature of oral cavity reconstruction can be com-plex. (See also Selected Readings in Oral and Maxillofacial Surgery, Vol. 2, # 7 ) For example, in areas like the soft palate the skin paddle may need to be folded for adequate reconstruction,



making the positioning and orientation of the pedicle of paramount importance.

Once the design is confirmed, the arm is exanguinated with an Esmark bandage and a tourniquet inflated to 250 mmHg. Flap elevation is begun at the distal-most aspect of the skin pad-dle. Incision through skin and subcutaneous fat and fascia allows for identification of the distal radial artery and cephalic vein, which are ligated and transected. The superficial branches of the radial nerve will also be encountered at this time and may be preserved or sacrificed depending on surgeon’s preference. The longitudinal borders of the skin paddle can now be incised through skin and subcutaneous tissue down through the fascia of the brachioradialis muscle radially and the flexor muscles on the ulnar side. This dissection continues in the subfascial plane to the lateral intermuscular septum between the

Flap design and orientation should be performed with care because the three dimensional nature of oral cavity reconstruction can be complex.brachioradialis and the flexor carpi radialis. Care must be taken to leave a thin film of paratenon on the tendons of the wrist flexors or wound complications due to skin graft failure will be a problem.

At this point, the proximal portion of the skin paddle can be incised. Care must be taken to avoid injury to the cephalic vein as it emerges from the flap in the subcutaneous fat. A linear incision is then made from the proximal portion of the flap to the antecubital fossa to facilitate dissection of the vascular pedicle. This incision is then undermined in the subcutaneous plane laterally and medially. Completion of the dissec-tion of the cephalic vein can be performed at this stage to the appropriate length and in a circum-ferential fashion. Finally, the flap can be elevated

from distal to proximal, carefully dissecting the radial artery and its venae comitantes. Vascular clips will be necessary to control the numerous branches to the surrounding musculature and radial bone. The fascia of the brachioradialis will need to be incised along its length in order to facilitate the proximal dissection of the radial artery. The proximal extent of this dissection is limited by the radial recurrent artery near the antecubital fossa (Fig. 16).

Once dissection is complete, the tourniquet is deflated and the flap reperfused for a period of at least 20 minutes. During this time, hemostasis can be achieved with cautery and hemoclips, and the final preparation of the recipient site can be performed. After an adequate reperfusion time, the flap can be harvested by utilizing hemoclips at the desired pedicle length. A suction drain is placed, and wound closure occurs in layers

with absorbable sutures in the deep tissue to reapproximate the divided fascia as well as the sub-dermal layer.

Primary closure of the proximal linear incision is easily achieved and may also be pos-sible for the area of the skin paddle. However, usually the skin paddle area requires skin graft coverage to avoid excessive tension. Either a split or full thickness graft may be used and in-set with resorbable sutures. The graft should be perforated to allow for seepage of fluid during healing. This graft should be compressed to the recipient bed by Vaseline® gauze and by gauze that is supported by a plaster splint fabricated to the volar aspect of the lower arm and hand. This splint should be left in place for seven days to prevent sheer forces on the skin graft. Prior to

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