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Posterior Pedicle Lateral Nasal Wall Flap:

New Reconstructive Technique for Large Defects of the Skull Base

Carlos M Rivera-Serrano, MD1

Luis H. Bassagaisteguy, MD 2

Gustavo Hadad, MD 2

Ricardo L Carrau, MD 3

Dan Kelly, MD 4

Daniel M. Prevedello, MD 5

Juan Fernandez-Miranda, MD 6

Amin B Kassam, MD 7

1Department of Otolaryngology-Head and Neck Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA

2 Department of Otolaryngology-Head & Neck Surgery, Medical School of Ciudad de Rosario,

Provincia de Santa Fe, Republica Argentina

3Department of Otolaryngology-Head & Neck Surgery The Ohio State University, Columbus, OH

4 Brain Tumor Institute, Department of Neurosurgery

John Wayne Cancer Institute, Santa, Monica, CA

5Department of Neurosurgery, The Ohio State University, Columbus, OH

6Department of Neurological Surgery,

University of Pittsburgh Medical Center, Pittsburgh, PA

7Department of Neurosurgery, University of Ottawa, Ottawa, CA

Financial Disclosure: -No funding support was required for the completion of this manuscript. -None of the authors have financial interests in companies or other entities that have an interest in the information in the contribution.

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Conflict of Interest: None

-This material has never been published and is not currently under evaluation in any other peer-reviewed publication. This material has not been presented.

Key words: Endoscopic approach, reconstruction, nasal, endonasal, skull base surgery, CSF leaks, reconstructive flap, pedicle flap, lateral wall of the nose

Corresponding author: Ricardo L. Carrau, M.D., F.A.C.S. Professor Department of Otolaryngology-Head & Neck Surgery The Ohio State University Medical Center 915 Olentangy River Road Suite 4000 Columbus, OH 43212 carraurl@gmail.com Ricardo.Carrau@osumc.edu

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Abstract Background: Indications for expanded endoscopic approaches continue to grow, resulting in

larger and more complex skull base defects. Reconstructive developments, however, have lagged

our extirpative capabilities. As the complexity of clinical scenarios continues to escalate,

challenging our current reconstructive strategies, we are compelled to develop alternative

techniques to prevent CSF leaks and protect neurovascular structures.

Objectives: In this article we demonstrate the anatomical basis for a new posterior pedicled flap

from the lateral wall of the nose (Carrau-Hadad or C-H flap) for the reconstruction of median

skull base defects, and present our early clinical experience.

Methods: Using a cadaveric model we designed a posterior pedicle flap comprising the nasal

inferolateral wall mucoperiosteum. We applied this information clinically, to reconstruct

transmural skull base defects.

Results: In our cadaveric model, we harvested and transposed C-H flaps into various defects of

the planum sphenoidale, sella turcica, clivus and nasopharynx. Then, we used the C-H flap in

four patients, successfully reconstructing their clival (n=3) and sellar (n=1) surgical defects. All

patients healed uneventfully.

Conclusions: Our anatomical study and early clinical experience support the use of the posterior

pedicle lateral nasal wall flap to reconstruct large cranial base defects resulting from endoscopic

skull base surgery in properly selected patients.

Level of Evidence: 2B

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INTRODUCTION:

A favorable outcome is expected following the endoscopic reconstruction of small

defects of the skull base, regardless of which technique or tissue is used; therefore, vascularized

flaps do not appear to be essential for the reconstruction of limited defects.1 In contrast, the use

of vascularized flaps for the reconstruction of large skull base defects, regardless of the surgical

approach (open or endoscopic) seems to be advantageous. Some have obtained adequate results

with the use of free tissue grafts such as fat, acellular dermis or fascia lata. Free grafts still are an

important part of our armamentarium (specially when a pedicle flap is not available). However,

vascularized flaps lead to faster and more reliable healing; thus, they are associated with a lower

risk of postoperative CSF leaks and their associated complications.2-9

Skull base defects resulting from expanded endonasal approaches (EEA) can be

extremely challenging to reconstruct due to their complexity and extent. Development of

reconstructive strategies have lagged that of extirpative techniques; thus, presenting a major

hurdle toward standardization and popularization of EEA.2-5 During the last five years, various

endonasal pedicled flaps have been developed, including the Hadad-Bassagasteguy nasoseptal

flap, and middle and inferior turbinate pedicled flaps.6-8 These flaps represent important

advancements that helped to decrease the incidence of postoperative CSF leaks to less than 5%.10

Availability, versatility and reliability have propelled the rapid popularization of the

Hadad-Bassagasteguy nasoseptal flap; however, tumor extension or prior surgery, involving the

nasal septum, rostrum of the sphenoid sinus or pterygopalatine fossa, may preclude its use. In

addition, the extent of the defect may require the use of multiple flaps, or a hybrid technique

combining vascularized flaps and free tissue grafts.2-5 Hence, current reconstructive algorithms

demand alternative reconstructive strategies.

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Following the patterns of nasal blood supply (“vascular tree”) one can design other

potential pedicled vascular flaps. We have benefited from the work of others, who have

characterized the vascular anatomy of the lateral nasal wall.11-17 Blood supply of the postero-

lateral nasal wall mainly originates from the sphenopalatine artery, a terminal branch of the

internal maxillary artery.11-14 The inferior turbinate, however, has a dual anterior and posterior

blood supply; although, its main blood supply arises posteriorly from the posterolateral nasal

artery (a branch of the sphenopalatine artery). 6, 13-15 We have taken advantage of this anatomical

attribute that serves as the foundation of our new reconstructive technique. In this article, we

describe an innovative pedicled flap comprising the mucoperiosteum of the infero-lateral wall

and floor of the nasal cavity, the Carrau-Hadad (C-H) flap, based posteriorly on branches of the

sphenopalatine artery. We demonstrate its anatomical basis using a cadaveric model and further

establish its feasibility with our early clinical experience.

MATERIALS AND METHODS

Our anatomical dissections were, completed at the Medical School of Rosario (Province

of Santa Fe, Argentina) and were reproduced at the Minimally Invasive Neurosurgery Center

(MINC) anatomy labs at the University of Pittsburgh Medical Center (approved by the

Committee for Oversight of Research Involving the Dead or CORID). Three fresh and five

preserved cadaveric specimens were used to design, harvest and transpose several modifications

of the C-H flap into various defects of the median skull base (see following description). To

better evaluate the vascular anatomy, we injected the specimens with colored silicone, using red

for the arterial system and blue for the venous system.18 Anatomic details and technical

variations revealed by the cadaveric model provided us with enough confidence to use the C-H

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flap clinically. Therefore, we used the C-H flap to reconstruct four patients, who required EEAs

at the John Wayne Cancer Institute (Santa Monica, CA) and the Instituto de Diagnostico y

Cirugia: Cabeza y Cuello, Nariz y Senos Faciales, Base Anterior de Craneo (Rosario, Argentina);

and, whose clinical presentation prohibited the use of the Hadad-Bassagasteguy nasoseptal flap

(HBF). Pertinent clinical data was reviewed retrospectively (IRB exemption granted).

Surgical Technique

Endonasal incisions can be made with a unipolar electrocautery fitted with an extended,

insulated needle tip (Valleylab, Boulder, Colorado) or a Colorado tip (Stryker Corporation,

Kalamazoo, MI). However, any sharp instrument may be adequate. Anteriorly, the

mucoperiosteum is incised along the anterior border of the ascending maxillary process, starting

at a level that corresponds to the most caudal aspect of the nasal bones and extending inferiorly

to the level of the head of the inferior turbinate (Figures 1 and 2). A second vertically oriented

incision is made along the posterior aspect of the lacrimal bone, starting at a level that is superior

to the anterior insertion (“axilla”) of the middle turbinate, and extending inferiorly to a level near

the upper aspect of the inferior turbinate. A third incision connects the most superior aspect of

the first two incisions.

According to the needs of each case, the anterior incision may extend further inferiorly

along the lateral nasal wall, just anterior to the inferior turbinate, and continue over the floor of

the nasal cavity to harvest a wider flap (Figures 1 and 2D). At its most infero-medial level, it

joins another incision (oriented in the sagittal plane), which extends posteriorly to a point that is

at the level of the sphenopalatine foramen (in the coronal plane; Figures 1, 2D). As previously

mentioned, this latter incision can be placed at the lateral nasal wall or carried medially over the

floor of the nose, to harvest a wider flap. The incision over the lacrimal bone (antero-posterior)

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joins a sagittal incision that extends posteriorly, over the superior aspect of the inferior turbinate,

to reach the sphenopalatine foramen. Some of the mucosa of the maxillary sinus fontanelle can

be incorporated into this incision to widen the surface area of the flap. Alternatively, this incision

can be part of a wide maxillary antrostomy. Resection of the middle turbinate greatly facilitates

the visualization and harvest of the flap, but is not mandatory. Another horizontal incision

crosses the floor of the nose at the level of the sphenopalatine foramen (in the coronal plane) to

connect the superior and inferior sagittal incisions, (Figures 1).

The head of the inferior turbinate is incised vertically and the incision is extended to

intersect the most anterior incision. This incision at the head of the turbinate is critical to harvest

the meatal aspect of the inferior turbinate mucoperiosteum (Figure 2E). The mucoperiosteum is

dissected with a Cottle or Freer periosteal elevator (Figure 2B), continuing its dissection along

the medial (nasal) aspect of the inferior turbinate bone. The bone may be sequentially removed

with true-cut and Kerrison rongeurs or any other preferred instrument (Figure 3A); and the

mucoperiosteum of the lateral (meatal) side is elevated, until it curves laterally at the level of the

opening of the nasolacrimal duct (Figures 3B and C). The opening of the nasolacrimal duct and

Hasner’s valve is preserved by incising around its periphery; thus, preserving it in situ (Figures

3D-F).

The mucoperiosteum is elevated further posteriorly along the lateral nasal wall (inferior

meatus and fontanelle) and the remaining floor of the nose component. (Figure 4). Special care

should be taken at the most posterior aspect of the flap, as the branches of the sphenopalatine

artery, especially the postero-lateral nasal artery, should be identified and preserved (Figure 4A).

Once elevated, the flap may be rotated posteriorly or superiorly with a pivot point at the

sphenopalatine foramen, or preserving a wider base that extends to the inferolateral nasal wall to

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the junction of the hard and soft palates (Fig 5). Due to its pivot point, its pedicle may needs to

be freed from the sphenopalatine foramen. This facilitates a rotation of up to 1800 from its

original position.

A temporary bolster using nasal packing helps to fixate the flap. As long as the pedicle is

free, its rotation does not cause significant retraction of the flap away from the defect. However,

a wider pedicle (extended to the floor of the nose) produces more torque and retraction. The C-H

flap dimensions were adequate to reconstruct the expanse from nasopharynx to planum

sphenoidale (antero-posterior), and from orbital apex to orbital apex or ICA canal to ICA canal

(latero-lateral).

RESULTS

In the cadaveric model, all C-H flaps were harvested using the previously described

technique and modifications, and were uneventfully transposed into a myriad of defects of the

median skull base. The PLNA and its inferior turbinate branch were routinely identified and

preserved during the harvesting of the flap. The C-H flap appeared to be adequate to reconstruct

defects of the planum sphenoidale, sella, clivus and nasopharynx. The only challenge was a

tendency for the inferior turbinate portion of the flap to return to its original shape.

Clinically, C-H flaps were used for the reconstruction of four patients whose presentation

prohibited the use of the Hadad-Bassagaisteguy nasoseptal flap. Three patients underwent a

trans-clival resection for recurrent clival chordomas that had been previously treated with

surgery and radiotherapy. One patient underwent an expanded endonasal resection for a recurrent

pituitary extrasellar adenoma that produced a large CSF leak. Harvesting of the flaps proceeded

in a fashion similar to our experience in the anatomical laboratory. All flaps appeared viable after

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harvesting, without discoloration or congestion. All four surgical defects were successfully

reconstructed with C-H flaps, which were transposed in place and fixated with a multilayer

bolster using gelatin sponges, tissue sealant, and strip-gauze or sponge packing (removed five

days after surgery). No perioperative lumbar spinal drain was used in any of the patients.

Postoperative viability and uneventful healing of the C-H flaps and nasal cavity were monitored

during the postoperative follow up visits. All patients required daily nasal toilette that included

self-administered saline lavages and moisturizing sprays; and, weekly or bi-weekly office

debridement for 6-8 weeks postoperatively. However, all four patients healed uneventfully with

no CSF leak or any other postoperative complication (Figure 6).

DISCUSSION

During the past two decades, we have witnessed the evolution of endoscopic endonasal

approaches, from trans-sphenoidal surgery for sellar lesions to expanded endonasal approaches

(EEA) for a variety of pathologies located along the ventral skull base.2-5 Their use to manage

skull base lesions has increased exponentially. Reconstructive developments, however, have

lagged our extirpative capabilities, and increasingly complex clinical scenarios continue to

challenge current reconstructive strategies.

Reconstructive objectives after resection of the skull base include protection of critical

neurovascular structures and separation of the cranial cavity from the sinonasal tract2-4; therefore,

decreasing the risk of postoperative cerebrospinal fluid (CSF) leaks and ascending bacterial

infections.1 An hermetic separation of cranial cavity and sinonasal tract also protects major

vessels against desiccation and infection that could lead to a vascular blow-out or

pseudoaneurysm.

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It has been demonstrated that repair of small CSF fistulas is successful in over 95% of

cases, independent of which biological tissue or surgical technique is used.1 Some have obtained

good results with the use of free grafting for the reconstruction of defects after endoscopic skull

base surgery. However, others have reported that the incidence of postoperative CSF leaks

increases significantly when free grafting techniques are used to reconstruct large cranial base

defects.2, 5, 8, 10

Pedicled mucosal and fascial flaps provide the most reliable, reproducible and optimal

reconstruction of large skull base defects. Reconstruction of skull base surgery defects using

vascularized tissue is associated with a significantly lower incidence of postoperative CSF leaks.

In our experience, the HBF posterior pedicle nasoseptal flap lead to a dramatic improvement in

our postoperative CSF leaks rate, currently less than 5%.4, 8, 10 However, the HBF is frequently

not available in patients who have undergone previous posterior septectomy or wide

sphenoidotomies, which compromise its pedicle; or when the donor site (nasoseptal mucosa) is

infiltrated by tumor. As a result, alternative endonasal reconstructive flaps have been developed;

however, these are yet not sufficient to provide an encompassing solution to the increasing size

and complexity of the defects, and the variability of clinical situations.6, 7, 19-23 Free grafting

remains as a viable alternative, however, as previously mentioned vascularized tissue alternatives

seem superior alternatives. Various extranasal pedicled flaps can also be used for the

reconstruction of large defects of the anterior skull base, such as the transfrontal pericranial

flap19, 20, the transpterygoid temporoparietal fascia flap7, the palatal flap21, the facial artery

buccinator flap (FAB)22, and the occipital galeopericranial flap24. These offer reconstructive

alternatives in select patients, but they may be technically challenging and are associated to some

donor site morbidity. Furthermore, in some patients, these flaps may not be available due to

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compromise of their pedicle or donor site by tumor or prior surgery. A posterior pedicle inferior

turbinate flap has been previously described for reconstruction of clival and sellar defects.6, 25 In

contrast to the posterior pedicle inferior turbinate flap, the C-H flap incorporates the mucosa

anterior to the middle turbinate, extending beyond the lateral wall to the mucosa covering the

nasal bones, as well as the mucoperiosteum of the inferior nasal lateral wall, inferior meatus and

nasal floor. This results in a flap with a potential surface area that is three times the surface area

of that of the inferior turbinate flap, and a superior reach.

The ideal candidate for the C-H flap is a patient with a large surgical defect resulting

from a transplanum, transsellar, transclival or middle cranial fossa EEA, in whom the Hadad-

Bassagaisteguy nasoseptal flap is not available. Contraindications to the C-H flap include the

need to sacrifice its mucosal surface, pedicle or proximal blood supply to achieve oncologic

margins, and prior surgery or embolization of its main blood supply. . Prior high dose

radiotherapy or chemoradiotherapy should be taken into consideration; however, the lateral nasal

wall is not within the usual radiation fields of tumors originating or extending to the clivus, sella

or planum sphenoidale. In the rare instance where the flap has been irradiated we anticipate a

tolerance similar to the nasoseptal flap.

Harvesting of the C-H flap is not difficult assuming that the surgeon has experience with

endonasal endoscopic surgery. However, meticulous attention to its technical harvesting is

paramount for a favorable outcome. The absence of the posterior nasal septum greatly facilitates

the harvesting process, as it provides more working space. We expect that this scenario will not

be uncommon as the lack of nasal septum (compromised HBF donor site) is one of the

indications for C-H flap.

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Based on our early clinical experience with the C-H flap and our acquaintance with other

endonasal flaps, we expect minimal morbidity in the vast majority of the patients. Initial

morbidity is mostly associated to temporary, albeit significant, nasal crusting, which lasts until

re-mucosalization of the donor site is complete. It has been our observation that mucosalization

of the donor site progresses more rapidly than that of the nasoseptal flap. It does require,

however, nasal toilette and endoscopic debridement (every 1-2weeks for about 6 weeks). We

have not encountered problems with lacrimal outflow despite harvesting mucosa very close to

the opening of the nasolacrimal duct in the inferior meatus

CONCLUSION

Our anatomical cadaveric dissections and early clinical experience support the use of the

posterior pedicle lateral nasal wall and floor flap for vascularized reconstruction of large ventral

cranial base defects in select patients.

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REFERENCES:

1. Hegazy H, Carrau R, Snyderman C, Kassam A, Zweig J .Transnasal endoscopic repair of cerebrospinal fluid rhinorrhea: a meta-analysis. Laryngoscope, 2000. 110(7): p. 1166-72

2. Kassam A, Carrau R, Snyderman C, Gardner P, Mintz A. Evolution of reconstructive

techniques following endoscopic expanded endonasal approaches. Neurosurg Focus, 2005. 19(1): p. E8.

3. Bhatki AM, Carrau RL, Snyderman CH, Prevedello DM, Gardner PA, Kassam AB. Endonasal Surgery of the Ventral Skull Base- Endoscopic Trans-cranial Surgery. OralMaxillofac Surg Clin North Am. 201 Feb; 22(1): 157-68.

4. Lund VJ, Stammberger H, Nicolai P, Castelnuovo P, Beham A, Bernal-Sprekelsen M,

Braun H, Cappabianca P, Carrau RL et al. European Position paper on endoscopic management of tumours of the nose paranasal sinuses and skull base. Rhinology. 2010 Jun 1; 48(2):1001-144.

5. Ong YK, Solares CA, Carrau RL, Snyderman CH. New Developments in transnasal

endoscopic surgery for malignancies of the sinonasal tract and adjacent skull base. Curr Opin Otolaryngol Head Neck Surg. 2010 Apr;18(2):107-13.

6. Fortes F, Carrau R, Snyderman C, Prevedello D, Vescan A, Mintz A, Gardner P, Kassam

A. The posterior pedicle inferior turbinate flap: a new vascularized flap for skull base reconstruction. Laryngoscope, 2007. 117(8): p. 1329-32.

7. Fortes F, Carrau R, Snyderman C, Kassam A, Prevedello D, Vescan A, Mintz A, Gardner

P. Transpterygoid transposition of a temporoparietal fascia flap: a new method for skull base reconstruction after endoscopic expanded endonasal approaches. Laryngoscope, 2007. 117(6): p. 970-6.

8. Hadad G, Bassagasteguy L, Carrau R, Mataza J, Kassam A, Snyderman C, Mintz A. A

novel reconstructive technique after endoscopic expanded endonasal approaches: vascular pedicle nasoseptal flap. Laryngoscope, 2006. 116(10): p. 1882-6.

9. Yoshioka N, Rhoton AL Jr., Vascular anatomy of the anteriorly based pericranial flap.

Neurosurgery. 2005 Jul;57(1 Suppl):11-6; discussion 11-6. 10. Zanation A, Carrau R, Snyderman C, Germanwala A, Gardner P, Prevedello D, Kassam A.

Nasoseptal flap reconstruction of high flow intraoperative cerebral spinal fluid leaks during endoscopic skull base surgery. Am J Rhinol Allergy. 2009; 23(5):518-21.

11. Babin E, Moreau S, de Rugy MG, Delmas P, Valdazo A, Bequignon A. Anatomic

variations of the arteries of the nasal fossa. Otolaryngol Head Neck Surg, 2003. 128(2): p. 236-9

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12. Lee HY, Kim HU, Kim SS, Son EJ, Kim JW, Cho NH, Kim KS, Lee JG, Chung IH, Yoon

JH. Surgical anatomy of the sphenopalatine artery in lateral nasal wall. Laryngoscope, 2002. 112(10): p. 1813-8.

13. Hadar T, Ophir D, Yaniv E, Berger G. Inferior turbinate arterial supply: histologic

analysis and clinical implications. J Otolaryngol, 2005. 34(1): p. 46-50. 14. Padgham, N. and R. Vaughan-Jones, Cadaver studies of the anatomy of arterial supply to

the inferior turbinates. J R Soc Med, 1991. 84(12): p. 728-30. 15. Murakami, C.S., J.D. Kriet, and A.P. Ierokomos, Nasal reconstruction using the inferior

turbinate mucosal flap. Arch Facial Plast Surg, 1999. 1(2): p. 97-100. 16. Penna, V., H. Bannasch, and G.B. Stark, The turbinate flap for oronasal fistula closure.

Ann Plast Surg, 2007. 59(6): p. 679-81. 17. Friedman, M., H. Ibrahim, and V. Ramakrishnan, Inferior turbinate flap for repair of nasal

septal perforation. Laryngoscope, 2003. 113(8): p. 1425-8. 18. Sanan A, Abdel Aziz KM, Janjua RM, van Loveren HR, Keller JT. Colored silicone

injection for use in neurosurgical dissections: anatomic technical note. Neurosurgery, 1999. 45(5): p. 1267-71; discussion 1271-4.

19. Zanation AM, Snyderman CH, Carrau RL, Kassam AB, Gardner PA, Prevedello DM.

Minimally invasive endoscopic pericranial flap: a new method for endonasal skull base reconstruction. Laryngoscope, 2009. 119(1): p. 13-8.

20. Patel MR, Shah RN, Snyderman CH, Carrau RL, Germanwala AV, Kassam AB, Zanation

AM. Pericranial flap for endoscopic anterior skull-base reconstruction: clinical outcomes and radioanatomic analysis of preoperative planning. Neurosurgery. 2010 Mar; 66(3): 506-12.

21. Oliver C, Hackman T, Carrau R, Snyderman C, Kassam A, Prevedello D, Gardner P.

Palatal Flap Modifications Allow Pedicled Reconstruction of the Skull Base. Laryngoscope, 2008.

22. Rivera-Serrano CM, Oliver CL, Sok J, Prevedello DM, Gardner P, Snyderman CH,

Kassam AB, Carrau RL. Pedicled Facial Buccinator (FAB) Flap: A New Flap for Reconstruction of Skull Base Defects. Laryngoscope. 2010 Jul 7. [Epub ahead of print

23. Prevedello D, Barges-Coll J, Fernandez-Miranda J, Morera V, Jacobson D, Madhok R,

Zanation A, Snyderman C, Gardner P, Kassam A, Carrau R. Middle turbinate flap for skull base reconstruction: cadaveric feasibility study. Laryngoscope. 2009 Nov; 119(11): 2094-8

24. Rivera-Serrano CM, Oliver C, Prevedello D, Gardner P, Snyderman C, Kassam A, Carrau

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RL. Pedicled Facial Buccinator (FAB) flap: a new flap for reconstruction of skull base defects. Laryngoscope. 2010;120 Suppl 4:S23

25. Harvey RJ, Sheahan PO, Schlosser RJ. Inferior turbinate pedicle flap for endoscopic skull base defect repair. Am J Rhinol Allergy. 2009

FIGURES:

Figure 1. Incisions for the C-H flap.

Dashed lines represent the incisions. Ant-Sup incision (large black arrow) = Antero-superior

incision. Ant-Inf incision = Antero-inferior incision. IT = Inferior Turbinate. MT = Middle

turbinate. ST = Superior turbinate. Small curved black arrows = blood supply of the flap. White

arrow = Nasolacrimal duct opening. Dashed black (circles) line and small black arrow = an

incision can be made at the nasal floor to increase the arc of rotation of the flap. Please note that

the antero-inferior incision is directed laterally (from the head of the inferior turbinate) towards

the meatal side of the inferior turbinate / nasolacrimal duct opening (correlate with figure 2), in

order to incorporate the lateral-inferior nasal mucosal wall of the inferior meatus. The medial

aspect of the inferior turbinate is not incised.

Figure 2. Harvesting of the C-H flap from left side.

A. Incisions. Gray arrow = stump of middle turbinate. B. Incision (white arrow) at the head of

the inferior turbinate. C. Incision and elevation of the flap from the ascending process of the

maxilla (apm). F = flap. Nv = nasal vestibule. D. Dashed line = Extension of the incision across

the nasal floor. Small white arrow = Direction of the sagitally oriented incision along the floor of

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the nasal cavity, just lateral to the nasal septum (which extends posteriorly to a point that is at the

level of the sphenopalatine foramen in the coronal plane). E. Harvesting of the meatal aspect of

the inferior turbinate mucoperiosteum (black arrow). F. Elevation of the most anterior aspect of

the flap (dashed line represent incisions – correlate with figure 1 and 2a).

Figure 3. Harvesting of the C-H flap from left side.

A. Residual inferior turbinate bone is removed with Kerrison rongeurs. B. The mucosa of the

lateral aspect of the middle turbinate is elevated until it turns laterally towards the opening of the

nasolacrimal duct. Gray arrow = residual bone of inferior turbinate. White asterisk = mucosa

from the meatal side of the middle turbinate is reflected laterally. White arrow = approximate

location of the opening of the nasolacrimal duct in the middle meatus. C. Scissors are used to

cut the meatal mucosa towards the opening of the nasolacrimal duct. D. White arrow points the

nasolacrimal duct opening. Dashed line = incision line towards the nasal floor (just inferior to the

nasolacrimal duct opening). E. Incision is carried down towards the nasal floor / nasal septum

in the coronal plane. F. The the mucoperiosteum is elevated from the middle meatus and

reflected medially. White arrow = nasolacrimal duct opening.

Figure 4. Harvesting of the C-H flap from left side.

The nasal septum has been removed in this specimen. A. The mucoperiosteum is further elevated

posteriorly along the lateral nasal wall and the floor of the nasal cavity. Branches of the

sphenopalatine artery (black arrowhead) should be identified and preserved. B. Lateral (wall)

aspect of the flap completely elevated. White arrow = nasal choana. C. Nasal floor component

of the flap completely elevated. Dashed line represents the sagittally oriented incision along the

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floor of the nasal cavity (correlate with Figure 2D). D. Harvested flap. Black asterisk = nasal

floor component of the flap.

Figure 5. Transposition of the C-H flap.

A. Surgical defect. Gray arrow = clival defect. White arrow = residual nasal septum. Black

asterisk = Left inferior turbinate. White asterisk = Sphenoid sinus. B and C. The flap is

approximated to the defect. D. Flap completely covering the sphenoid sinus and clival

defect

Figure 6. Postoperative MRI.

Sagittal T1 weighted contrasted MRI demonstrating the vascularized C-H flap (arrows)

combined with a free abdominal fat graft (arrowheads) to reconstruct a clival defect.