CONTINUING MEDICAL EDUCATION

Surgical technique for optimal outcomes

Part I. Cutting tissue: Incising, excising, and undermining

Christopher J. Miller, MD,a Marcelo B. Antunes, MD,b and Joseph F. Sobanko, MDa

Philadelphia, Pennsylvania, and Austin, Texas

Learning objectives

After completing this learning activity, participants should be able to describe common errors during the removal of tissue that lead to unaesthetic scars and delineate the steps for

proficient fusiform excisions.

Disclosures

Editors

The editors involved with this CME activity and all content validation/peer reviewers of the journal-based CME activity have reported no relevant financial relationships with

commercial interest(s).

Authors

The authors involved with this journal-based CME activity have reported no relevant financial relationships with commercial interest(s).

Planners

The planners involved with this journal-based CME activity have reported no relevant financial relationships with commercial interest(s). The editorial and education staff involved

with this journal-based CME activity have reported no relevant financial relationships with commercial interest(s).

From

ni

Vide

Fund

Conf

Acce

Corre

H

Sound surgical technique is necessary to achieve excellent surgical outcomes. Despite the fact thatdermatologists perform more office-based cutaneous surgery than any other specialty, few dermatologistshave opportunities for practical instruction to improve surgical technique after residency andfellowship. This 2-part continuing medical education article will address key principles of surgicaltechnique at each step of cutaneous reconstruction. Part I reviews incising, excising, and undermining.Objective quality control questions are proposed to provide a framework for self-assessment and continuousquality improvement. ( J Am Acad Dermatol 2015;72:377-87.)

Key words: excise; excision; incise; skin; surgery; suture; technique; undermine.

INTRODUCTION While surgeons nearly universally adhere to the

Surgeons influence the aesthetics of scars from

cutaneous surgery in 2 ways: (1) surgical design and(2) surgical technique. The principles of aestheticsurgical design are universally accepted, and includepreserving and restoring free margins (eg, eyelids,nasal tip and ala, lips, and helical rim), preservingand restoring contour, and placing scars in cosmeticsubunit junction lines.1 Placing scars alongrelaxed skin tension lines is also desirable, but isless important compared to the aforementionedprinciples.2 For example, it is undesirable to conformto the horizontal relaxed skin tension lines on theforehead if elevation of the ipsilateral eyebrowcreates asymmetry.

the Department of Dermatology,a University of Pennsylva-

a, Philadelphia, and Private practice,b Austin.

o available at http://www.jaad.org.

ing sources: None.

licts of interest: None declared.

pted for publication June 17, 2014.

spondence to: Joseph F. Sobanko, MD, Edwin & Fannie Gray

all Center for Human Appearance, University of Pennsylvania,

core principles of aesthetic surgical design, surgicaltechnique varies markedly. These variations canconfuse surgical trainees, who are left to struggleby trial and error through numerous potentialapproaches to execute the same surgical tech-nique.3,4 Only after months to years of independentpractice and observation of their own postoperativeoutcomes domost surgeons refine their own surgicaltechnique and achieve reproducibly excellentresults.5 Many practitioners desire additionalsurgical coaching after their formal training.6

This 2-part continuing medical education articleproposes quality control questions for each stepof cutaneous reconstruction and provides a

3400 Civic Center Blvd, Rm 1-330S, Philadelphia, PA 19104.

E-mail: Joseph.Sobanko@uphs.upenn.edu.

0190-9622/$36.00

� 2014 by the American Academy of Dermatology, Inc.

http://dx.doi.org/10.1016/j.jaad.2014.06.048

Date of release: March 2015Expiration date: March 2018

377

Fig 1. A, Ideal appearance of a wound on the forehead 1 week postsurgery, with sutures still inplace. There is minimal erythema. B, Appearance of the same wound on the foreheadimmediately after removing the sutures. Precise approximation of the wound edges andminimal inflammation reflect sound surgical technique and portend a minimally apparent scar.

J AM ACAD DERMATOL

MARCH 2015378 Miller, Antunes, and Sobanko

framework for self-assessment and continuous qual-ity improvement.

STEPS OF SURGICAL RECONSTRUCTIONSurgical techniques fall into 2 broad categories:

cutting and suturing. Cutting techniques includeincising, excising, and undermining. Suturingtechniques include placing deep and top sutures.Most reconstructive surgery involves the stepwiseexecution of these cutting and suturing techniques.Each step influences the success of subsequentsteps; errors early in the process make the preciseexecution of subsequent steps either more difficultor impossible.

Scars heal with a shiny texture that reflects lightmore brightly than the textured, normal surroundingskin. Sound surgical technique must therefore aim todiminish the contrast between scar and normal skinby minimizing the breadth of the scar.7-9 Precise,tension-free approximation of the skin edges allowsfor prompt reepithelialization and a barely visiblescar.10,11 The appearance of scars often improveswith time, helping to disguise minor technicaldeficiencies.12 The appearance of the wound 1week after surgery gives an honest assessmentof the precision of the surgical technique.Completely reepithelialized scars with minimal tono inflammation signify meticulous surgical tech-nique (Fig 1). Wounds with prominent inflammationand focal inversion or separation of wound edgesusually result from suboptimal surgical technique(Fig 2). In these continuing medical educationarticles, we analyze each step of cutting and suturingand propose quality control checkpoints forobjective self-evaluation. Part I reviews cuttingtechniques, including incising, excising, and under-mining. Part II reviews suturing techniques,including placing deep and top sutures. Spaceprecludes a comprehensive coverage of surgical

techniques; we therefore focus on core techniquesthat apply broadly to any surgeon performingsurgery of the skin.

CUTTING TECHNIQUE: INCISINGKey pointsd The incision aims to achieve uniform releaseof the entire skin edge to the desiredanatomic depth

d The ideal depth of the incision variesaccording to the anatomic location andintent of the procedure

d The incised wound edges should be smoothand sharply perpendicular to the skinsurface

d Beveling of the dermis or fat toward thecenter of the wound impedes the preciseapproximation of wound edges

The goal of the incision is to achieve uniformrelease of the entire skin edge to the desiredanatomic depth and to create smooth andperpendicular wound edges without a bevel.13

Before beginning the procedure, the surgeon shouldhave a clear plan for the anatomic depth of theincision. The desired anatomic depth will vary basedon the location and intent of the procedure. In mostcases, the depth of the incisionwill correspond to theintended anatomic plane for the subsequent steps ofexcision and undermining. The skin should bereleased to a uniform depth along the entire incision(Fig 3).

The incision should create wound edges that aresharply perpendicular to the skin surface, becauseany bevel of the dermis or fat will impede the directapposition of the epidermal edges during suturing(Fig 4). Beveled wound edges will force the surgeonto place excessive tension on the sutures, a practicethat increases the risk of leaving suture marks on

Fig 5. Typical long-term appearance of a scar repairedwith excessive tension on the superficial sutures. The scarhas spread, and prominent track marks are present.

Fig 2. Suboptimal appearance of a wound 1 weekpostsurgery and immediately after removing thecutaneous sutures. Prominent inflammation and inversionof the wound edges have resulted from imprecise surgicaltechnique and signal an opportunity to improve technicalskills.

Fig 3. The incision should achieve uniform release to thedesired anatomic depth. Note this fusiform incision wherethe tips have not been incised to the same depth as thesides of the specimen. The tips (black arrowheads) requireadditional release.

Fig 4. Intraoperative appearance of a wound repairedwith suboptimal technique. The black arrow indicates aprominent beveled edge of the dermis. The beveleddermis will prevent direct approximation of the woundedges, regardless of the quality of the buried sutures. In anattempt to close the gap between the epidermal edges, thesuperficial sutures have been placed with excessivetension. The prominent gap at the puncture site of thesuperficial sutures (black arrowhead) risks track marks.

J AM ACAD DERMATOL

VOLUME 72, NUMBER 3Miller, Antunes, and Sobanko 379

each side of the scar (Fig 5). The angle of the scalpelrelative to the skin influences whether or not theincision creates beveled wound edges. The scalpelhandle tends to fall toward the surgeon’s dominanthand, similar to the eraser end of a pencil, therebypositioning the blade in an undesirable beveledposition (Fig 6, A). The surgeon must compensatefor this natural tendency by taking care to hold thescalpel perpendicular to the surface of the skinthroughout the entire pass of the incision (Fig 6, B).

Cleanly incised wound edges facilitate preciseapproximation of the epidermis and dermis duringsuturing. Jagged wound edges complicate suturing.A sharp scalpel should incise the skin smoothly withminimal downward pressure. If the surgeon forcesthe scalpel with downward pressure in an attempt toreach the desired depth in 1 pass, or if the scalpeledge is dull, the scalpel may succumb to chatter,resulting in jagged wound edges. To avoid chatter,

especially in thick or fibrotic skin, [1 pass of thescalpel may be necessary to reach the desireddepth. If multiple passes are necessary to incisethrough thick skin (eg, on the back and proximalextremities), applying pressure of the scalpel againstthe outside wound edge can decrease the risk for abevel on subsequent passes. Using the nondominant

Fig 6. A, Suboptimal surgical technique, with the scalpel handle falling toward the dominanthand. This position predictably incises the skin with a beveled edge. B, Sound surgicaltechnique, with the scalpel handle and blade held perpendicular to surface of the skin. Thisposition will help to incise the skin with a vertical wound edge and no bevel.

Fig 7. A, Intraoperative appearance of a wound after incision, excision, and undermining. Theepidermis and dermis have retracted away from the center of the wound more than thesubcutaneous fat. The lagging fat (black arrowhead) creates a beveled edge that obscuresvisualization of the reticular dermis and will obstruct direct approximation of the dermis. B,Intraoperative appearance of the same wound showing the technique of using tissue scissors totrim to the lagging fat bevel flush with the dermis. The fat bevel on the superior wound edgehas already been trimmed and now has an incised wound edge with a precisely vertical face.

J AM ACAD DERMATOL

MARCH 2015380 Miller, Antunes, and Sobanko

hand to stabilize the skin with gentle downwardpressure (as opposed to lateral traction) also mini-mizes a beveled dermis with each pass of the scalpel.

The epidermis and dermis have greater surfacetension compared to subcutaneous fat. After incisingthrough the dermis, the epidermis and dermisimmediately retract away from the incision, and thesubcutaneous fat tends to lag toward the center ofthe wound (Fig 7, A). If the lagging fat obscures thedermis or extrudes between the wound edges duringthe placement of deep sutures, trimming it flush withthe dermis allows for greater visibility of the reticulardermis for accurate placement of the buried dermalsutures (Fig 7, B). In many cases, this is bestaccomplished after undermining. Using forceps togently stabilize the lagging fat, the surgeon can usetissue scissors to trim the fat flush with the dermisand create a sharply perpendicular wound edgealong the full thickness of the skin flap. Excessivetraction should be avoided, because it frequently

causes a reverse bevel (ie, a bevel away from thecenter of the wound), which makes it more difficultto place the deep sutures without a prominentdimple.

Goal of incisionThe goal of incision is to achieve a uniform release

along the entire skin edge to the desired anatomicdepth and to create smooth and perpendicularwound edges with no bevel.

Quality control checkpoints for incision

1. Has the incision achieved uniform release to thedesired anatomic plane?a. Troubleshooting #1—If the incision has

not reached the desired anatomic depth,complete the incision to get uniform release.

b. Troubleshooting #2—If the incision extendsmore deeply than the intended depth of

J AM ACAD DERMATOL

VOLUME 72, NUMBER 3Miller, Antunes, and Sobanko 381

the excision and undermining, be careful thatthe subsequent steps of excision and under-mining occur in the correct anatomic plane.

2. Are the incised wound edges perpendicularwithout a bevel of the dermis or fat?a. Troubleshooting #1—If the dermis is cut with

a beveled edge, ensure that the angle of thescalpel is perpendicular to the plane of theskin throughout the entire pass of the incision(Fig 6, B).

b. Troubleshooting #2—If the dermis is cutwith a beveled edge, assess the methodof stabilizing the skin. The application ofdownward pressure perpendicular to thesurface of the skin is less likely to produce abeveled edge compared to stretching eachside of the skin away from the path of theincision.

c. Troubleshooting #3—To avoid a beveleddermal edge, consider using a no. 10 scalpelfor anatomic locations with a thick dermis.

d. Troubleshooting #4—If the dermis is cut witha beveled edge, grip the redundant tissuewith a forceps and apply gentle traction intothe wound. Incise through the beveleddermis to create a clean and perpendicularedge.

e. Troubleshooting #5—If the subcutaneous fatis lagging in the center of the wound, considerusing tissue scissors to trim the lagging fatflush with the vertical face of the inciseddermis (Fig 7, B).

3. Are the wound edges cut cleanly without jaggededges?a. Troubleshooting #1—Jagged edges may occur

from excessive downward pressure or the useof a dull scalpel. Ensure that the scalpelis sharp and pass the scalpel lightly, allowing[1 pass to achieve the desired depth, ifnecessary.

b. Troubleshooting #2—Jagged edges may occurif loose skin is not stabilized while incising.Improve stabilization of the skin whileincising.

Common errors to avoid during incision

1. Failure to incise to the desired anatomic depth(ie, either too superficial, leading to no release,or too deep, leading to bleeding through thegulley from the incision)

2. Holding the scalpel at an angle that creates abeveled edge

3. Jagged wound edges resulting from chattercaused by excessive downward pressure on thescalpel, from a dull blade, or from a failure tostabilize the skin while incising

CUTTING TECHNIQUE: EXCISINGKey pointsd Excision should remove the lesion or excessskin during the reconstruction with minimalcollateral damage to important anatomicstructures

d The anatomic plane of the excision ideallycorresponds to the depth of initial skinincision; otherwise, hemostasis may bemore challenging or bulky soft tissue in thecentral wound may impede apposition ofwound edges

d The ideal anatomic plane of excision variesby location on the body

d Ideal planes of excision are characterized bythe effortless release of tissue and minimalbleeding

Excision has 2 purposes: either to (1) ensurecomplete removal of a lesion or to (2) restorecontour by removing the standing cone or excesstissue during the reconstruction. Based on theclinical examination and pathology of the preoper-ative biopsy specimen, the surgeon must determinethe anatomic depth of the excision. The excisionshould remove the lesion or excess skin withminimal collateral damage to important anatomicstructures. Deeply infiltrating tumors may requireexcision to a depth that causes predictablemorbidity. For example, a tumor that invadesthe deep fat on the temple may require excision ofthe temporoparietal fascia and may sacrifice thetemporal branch of the facial nerve. By contrast,the surgeon can almost always dictate the anatomicplane when excising standing cones or excess tissueduring the reconstruction. The ideal anatomic planesfor different anatomic locations can be found inTable I.

Ideally, the preceding incision has released theskin to the desired anatomic depth and the excisioncontinues a clean lift of tissue in the same surgicalplane. In areas with thick subcutaneous fat, adisparity between the depths of the incision andexcision may create unnecessary challenges duringthe closure. For example, if the incision extends tothe fascia, but the tissue is excised at the level of thesuperficial subcutaneous fat, then the island ofsubcutaneous fat at the base of the wound canimpede advancement of the wound edges during

Table I. Ideal surgical planes for incising, excising, and undermining

Anatomic location Preferred anatomic plane Comments/critical structures to consider

Trunk and extremities Junction of subcutaneous fatand deep fascia

In areas on the trunk and proximal extremities, with a thickerlayer of subcutaneous fat, the ideal surgical plane is thejunction between the tightly organized, compact, columnarfat lobules adherent the underside of the dermis and theunderlying, looser, larger, and more disorganized fat lobulesthat invest and obscure the fascia

Lateral aspect of theface and neck

Junction of the subcutaneousfat and SMAS

The motor branches from the facial nerve always lie deep tothe most superficial layer of SMAS (in areas where themuscles of facial expression are layered [eg, lip depressorsand elevators], the motor nerves innervate the deepestmuscles from their superficial surface); excision at thejunction of the subcutaneous fat and SMAS will alwaysprotect the motor nerves

Central third of faceand scalp

At the junction of subcutaneousfat and SMAS or deep to themuscles of the SMAS or galea(on scalp)

Because the branches of the facial nerve have arborized beforereaching the central third of the face, excision deep to theSMAS is less likely to cause motor deficits (eg, excision ofmidline and paramedian frontalis muscle does not leavemotor deficit on the forehead); on the midline nose,forehead, and scalp, undermining deep to the SMAS isfrequently desirable

SMAS, Superficial musculoaponeurotic system.

Fig 8. This intraoperative photograph shows adiscrepancy between the anatomic depths of the incisionand excision. The incision has released to the fascia. Thecentral island of tissue is being excised in the superficialsubcutaneous fat. A gully (arrowhead) left by the deeperincision often creates challenges for hemostasis, and thecentral island of fat can impede advancement of thewound edges. Excising the specimen with tissue scissorsreduces the likelihood of this error by providing improvedtactile feedback from the release of the anatomic planes.

Fig 9. On the trunk and extremities, the ideal surgicalplane is at the junction of the tightly organized, columnarfat adherent to the dermis and the larger, loosely organizedfat lobules that invest the deep muscular fascia.

J AM ACAD DERMATOL

MARCH 2015382 Miller, Antunes, and Sobanko

the closure and complicate hemostasis by obscuringblood vessels (Fig 8).

On the scalp, central face and temples, hands andfeet, and male genitalia, the subcutaneous fat iseither thin or indistinct (eg, on the mid-chin, thementalis muscle inserts directly into the dermis andthere is not a distinct layer of fat), so the surgeonencounters the underlying muscle or fasciaimmediately after release of the dermis. In themedial

aspect of the cheek, neck, trunk, proximalextremities, and female genitalia, there is frequentlya thicker layer of subcutaneous fat. In these loca-tions, a layer of columnar, compact, and tightlyorganized fat lobules adheres to the underside ofthe dermis. A surgical plane separates these tightlyorganized columnar lobules from a deeper layer oflarger, more loosely organized fat lobules that investthe fascia (Fig 9). Vigorous scrubbing with gauze canoften dislodge these deeper, loosely organized,larger fat lobules from the fascia. The junction of

Fig 10. Excising and undermining superficial to thesuperficial musculoaponeurotic system of the face andinvesting cervical fascia of the neck preserves theunderlying branches of the facial nerve on the lateralface and the spinal accessory nerve in the posteriortriangle of the neck.

Fig 11. On the central face, where there is minimal riskfor motor deficits from working in a deep surgical plane,the anatomic plane of excision is usually deep to themuscles of facial expression/superficial musculoaponeur-otic system. For smaller procedures, the surgeon maychoose a surgical plane superficial to the superficialmusculoaponeurotic system.

Fig 12. On the scalp, the anatomic plane of the excision isusually deep to the galea aponeurotica.

J AM ACAD DERMATOL

VOLUME 72, NUMBER 3Miller, Antunes, and Sobanko 383

these 2 layers of fat provides a natural and efficientsurgical plane that releases effortlessly. Optimalplanes for excision vary by location (Table I).Excising at the junctions of tissue planes minimizesbleeding and allows for effortless dissection. On thetrunk and extremities, the junction of the subcutane-ous fat and deep muscular fascia provides an idealsurgical plane (Fig 9). In order to preserve the

underlying branches of the facial nerve on the lateralaspect of the face and the spinal accessory nerve inthe posterior triangle of the neck, the surgeonexcises at the junction of the subcutaneous fat andfascia of the superficial musculoaponeurotic system(SMAS; Fig 10). On the central face, excising deep tothe muscles of facial expression/SMAS poses aminimal risk for motor deficits (Fig 11). Whereasthe most common surgical plane on the nose andcentral forehead is deep to the SMAS, it is morecommon to work superficial to the orbicularis orismuscle around the mouth. For smaller procedures inthe central face, the surgeon may choose asurgical plane superficial to the SMAS. In the midlineforehead, for example, the surgeon may choose tostay above the frontalis for a small horizontalexcision in order to minimize postoperative sensorydeficits, but may excise deep to the frontalis toremove bulk and facilitate tissue advancement for alarge excision. On the scalp, the anatomic plane ofthe excision is usually deep to the galea apo-neurotica (Fig 12).

The surgeon can use either scissors or a scalpel forexcision. Scissors have some advantages overscalpels, especially when the surgeon does nothave intimate knowledge of the surgical planes.Compared to the scalpel, scissors provide moretactile feedback, which helps the surgeon feel therelease of tissue and maintain a uniform anatomicplane. Scissors should split the anatomic plane withease, especially in healthy skin without fibrosis froma previous scar. Undue resistance during excisionshould prompt the surgeon to reevaluate theaccuracy of the anatomic plane. In contrast toscissors, the blind, sharp edge of the scalpel moreeasily breaches tissue planes. Especially in areas withthick subcutaneous fat, such as the abdomen or

Fig 14. Examining the base of the wound for a uniformsurgical plane serves as a quality control checkpoint. Theplane of excision on the anterior surface of the neck seenin this photograph is immediately superficial to theplatysma muscle, providing a relatively bloodless andefficient surgical plane.

Fig 13. Assessing the excision specimen for uniformthickness serves as a quality control checkpoint. Thefusiform excision specimen in the photograph has auniform thickness in profile. In this case, the small excisionspecimen was removed in plane of the superficialsubcutaneous fat. Excising the specimen at the junctionof the subcutaneous fat and fascia is usually a moreefficient surgical plane that allows for easier isolation ofvessels for hemostasis.

J AM ACAD DERMATOL

MARCH 2015384 Miller, Antunes, and Sobanko

proximal thigh, there is a tendency for the scalpel tocut progressively deeper during the excision and forthe underside of the specimen to have scallopedincisions. The surgeon should aim for a cleanseparation of anatomic planes and an excisionspecimen with a uniform thickness in profile thatreflects the accuracy of the plane of excision (Fig 13).

Goal of excisionThe goal of excision is to remove the skin in a

uniform and efficient anatomic plane with minimalmorbidity to the underlying structures.

Quality control checkpoints for excision

1. Is the excision effortless and does it causeminimal bleeding?a. Troubleshooting—Undue resistance or exces-

sive and diffuse bleeding from small vesselsfrequently signifies an inefficient plane ofexcision. Reevaluate the plane of excisionand aim for the junction of tissue planes,where excision usually occurs effortlessly andwith less bleeding (Figs 9-12).

2. Does the excision specimen have a uniformthickness (Fig 13)?a. Troubleshooting—If the profile view of the

excised specimen has varying thicknesses,then consider using scissors, rather than ascalpel, to gain the tactile feedback that helpsmaintain a uniform anatomic plane duringexcision.

3. Does the base of the wound have a uniformdepth at the desired anatomic plane (Fig 14)?a. Troubleshooting—If the base of the wound

does not have a uniform anatomic depthbecause of a partially shallow excision, thencomplete the excision of the remainingsuperficial tissue to the desired anatomicplane. If portions of the wound have beenexcised more deeply than the preferredanatomic depth, be careful that underminingoccurs more superficially at the preferredanatomic plane.

Common errors to avoid during excision

1. Failure to excise the specimen in a uniformanatomic plane

2. Mismatch between the anatomic depths of theincision and excision

3. Failure to excise the tissue at the junction oftissue planes

CUTTING TECHNIQUE: UNDERMININGKey pointsd Undermining may facilitate advancement ofthe wound edges and eversion whensuturing

d Wounds at anatomic sites where the fascia isadherent to the overlying dermis benefitmost from undermining

d Excessive undermining can threaten theblood supply of the flap and rarely providesa mechanical advantage

d The plane of undermining frequentlycorresponds to the plane of excision

Fig 15. Sharp undermining improves operative efficiency.When working in efficient surgical planes, sharp under-mining occurs with ease. This photograph shows thepractice of sliding 1 blade of the tissue scissors in thedesired surgical plane, then using the second blade tocomplete the release. Using this slide and divide techniqueof undermining, the surgeon does not have to rediscoverthe preferred undermining plane with each new cut.

J AM ACAD DERMATOL

VOLUME 72, NUMBER 3Miller, Antunes, and Sobanko 385

d An efficient plane of undermining is charac-terized by effortless release of the tissue andminimal bleeding

d Efficient undermining requires effectivecountertraction, most frequently appliedwith a skin hook, directly over the point ofrelease

The goals of undermining are to (1) facilitatetissue advancement by releasing either the skinedges or flap from underlying adhesions and to(2) facilitate eversion of the wound edges duringsuturing. The surgeon must make 2 key decisionswhen undermining: (1) the ideal anatomic plane forundermining and (2) the extent of undermining(ie, how widely to undermine). In most cases, theanatomic plane for undermining coincides with thedepth of the incision and the plane of the excision.

If the surgeon is working in an efficient surgicalplane, undermining should occur with ease. Undueresistance while undermining usually signifies aninefficient anatomic plane (eg, most commonlysplitting the subcutaneous fat rather than workingat the junction of the fat and fascia). The ideal surgicalplane varies based on the location (Table I and Figs 9-12). In some instances, undermining at a moresuperficial anatomic depth than the excision canminimize morbidity. For example, if excision of thetemporoparietal fascia is necessary to clear a tumoron the temple, the surgeon may decrease morbidityto the underlying temporal branches of the facialnerve by undermining the edges of the reconstruc-tion superficial to the temporoparietal fascia.

The extent of undermining varies according to theprocedure. For primary closures, wide underminingrarely increases mobility of the skin edges. Minimalundermining (ie, 0.5-1.0 cm) will usually suffice.For deep wounds or very loose skin (eg, on theforearm or lateral aspect of the neck), underminingmay not be necessary. Fascial plication suturescan advance tissue and decrease undermining re-quirements.14 To decide whether undermining isnecessary, the surgeon can use a skin hook to pullthe incised wound edge to its desired position.If underlying adhesions restrict mobility or fixthe skin in an inverted position, undermining willhelp. Undermining is most beneficial in areaswhere the fascia and the underlying dermis havedense connections (eg, the muscles of facial expres-sion inserting in the dermis at the apical triangle ofthe lip).

Undermining influences the vascular supply andmobility of the flap. The vascular supply to the flapvaries according to anatomic plane and the extentof undermining. Flaps elevated too superficially(eg, immediately subdermal) may not have adequate

blood supply.15 To optimize blood supply, localflaps should contain at least the epidermis, dermis,and the tight columnar cells of subcutaneousfat immediately adherent to the dermis (Fig 9).Undermining deep to muscle or fascia improvesflap blood supply but may increase morbidity,depending on the anatomic location of the surgery(Table I). For example, in the central face (eg, thenose and central forehead) and scalp, underminingdeep to the muscles of facial expression or galea,respectively, is desirable in most cases (Figs 11 and12). By contrast, on the lateral aspect of the face,temple, and posterior triangle of the neck,undermining superficial to the SMAS and investingfascia of the neck, respectively, preserves function ofthe underlying motor nerves (Fig 10).

Undermining too widely can threaten a flap’sblood supply or increase the possibility ofpostoperative bleeding and hematoma forma-tion.16-18 In general, the surgeon should aim toundermine just enough to move the flap into place.Frequent assessment of skin edge mobility whileundermining helps to avoid unnecessarily wideundermining. When the skin edges comfortablystretch to their desired target, additional undermin-ing is rarely helpful or necessary.

Sharp undermining improves efficiency. With athorough knowledge of anatomy, the surgeon canundermine sharply and with confidence. Comparedto the scalpel, scissors allow sharp undermining withbetter tactile feedback. The scissors precisely releasethe skin at the desired surgical plane. After the initialreleasing cut, the surgeon can efficiently underminethe remaining skin by sliding 1 blade of the scissorsin the newly released space and by using the secondblade to complete the cut (Fig 15). Using this slide

Fig 16. The wound edges have been undermined in thesame surgical plane as the base of the excision. In this caseon the temple, the surgical plane is at the junction of thesubcutaneous fat and the superficial musculoaponeuroticsystem.

Fig 17. Upon final inspection from the cutting steps, thesurgeon should observe a wound with cleanly incised,vertical wound edges, a wound base uniformly located atthe preferred anatomic plane, and skin flaps underminedenough to allow advancement and eversion of the woundedges.

J AM ACAD DERMATOL

MARCH 2015386 Miller, Antunes, and Sobanko

and divide technique,19,20 the surgeon does not haveto rediscover the preferred undermining plane witheach new cut. Blunt undermining may be preferredwhere fascial planes are being separated, such as onthe dorsal surface of the hand or under the galea ofthe scalp. These avascular planes may be split simplyby inserting the closed tips of the scissors in thedesired plane of undermining then spreading theinstrument.

Countertraction with skin hooks greatly facilitatesundermining. Compared to forceps, skin hooksallow forceful countertraction of the skin withoutepidermal trauma. The skin hook should be placedfirmly at the desired depth of undermining (usuallyfirmly under the dermis) immediately over the pointof undermining. If the skin hook is placed toosuperficially (eg, in the mid-dermis), the instrumenttends to slip from the skin. If the skin hook is placedremotely from the point of undermining with thescissors, the forces of countertraction diminish andundermining is more difficult. Therefore, as thescissors progress to a new spot, the retracting skinhook should follow. When undermining iscomplete, there is often a bevel of subcutaneous fatalong the incised face of the skin edge. Tissuescissors can be used to trim this fat bevel flush withthe dermis (Fig 7, B).

Goal of underminingThe goal of undermining is to facilitate

advancement of skin edges by releasing the skinedges from underlying adhesions and to facilitateeversion of the wound edges during suturing.

Quality control checkpoints for undermining

1. Is undermining effortless, and does it causeminimal bleeding?

a. Troubleshooting #1—If undermining isdifficult, reassess the surgical plane (Table I).Resistance during undermining frequentlyoccurs from working in a suboptimal surgicalplane.

b. Troubleshooting #2—If undermining isdifficult, evaluate whether countertractionwas performed effectively. Efficient under-mining requires forceful countertractiondirectly over the point release. Underminingwill feel difficult if countertraction is eitherabsent or remote from the exact point ofundermining.

2. Can the incised skin edge be retracted in aneverted position?a. Troubleshooting—If a skin hook cannot

retract the skin edge in an everted position,then connective tissue adhesions will likelyforce the wound edge in an inverted position.The wound edge may need additionalundermining before suturing. Wide under-mining rarely facilitates eversion.

3. Are the wound edges sharply perpendicular fromthe epidermis to the plane of undermining?b. Troubleshooting—After undermining, there is

often a bevel of subcutaneous fat along theincised face of the skin edge. Tissue scissorscan be used to trim this fat bevel flush withthe dermis (Fig 7, B).

Common errors in undermining

1. Undermining in a suboptimal surgical plane

2. Undermining without effective countertraction

3. Insufficient undermining that restricts eversion ofthe incised wound edge

4. Failure to trim the fat bevel to create sharplyperpendicular wound edges after undermining

J AM ACAD DERMATOL

VOLUME 72, NUMBER 3Miller, Antunes, and Sobanko 387

CONCLUSIONThe initial steps to cutaneous surgery require

cutting, including incising, excising, and under-mining. After the cutting steps, the ideal wound hascleanly incised, vertical wound edges, a base at auniform anatomic plane, and precisely underminedskin edges (Figs 16 and 17). Part I of this continuingmedical education article provided qualitycontrol checkpoints and troubleshooting solutionsto address common challenges during incision,excision, and undermining to help surgeons createwounds ideally suited for repair with precise andefficient buried and superficial sutures.

REFERENCES

1. Burget GC, Menick FJ. Aesthetic reconstruction of the nose.

St Louis: Mosby; 1994.

2. Robinson JK. Segmental reconstruction of the face. Dermatol

Surg. 2004;30:67-74.

3. Peyre SE, Peyre CG, Sullivan ME, Towfigh S. A surgical skills

elective can improve student confidence prior to internship.

J Surg Res. 2006;133:11-15.

4. Graziano SC. Randomized surgical training for medical

students: resident versus peer-led teaching. Am J Obstet

Gynecol. 2011;204:542.e1-e4.

5. Halm EA, Lee C, Chassin MR. Is volume related to outcome in

health care? A systematic review and methodologic critique of

the literature. Ann Intern Med. 2002;137:511-520.

6. Gawande AA. Personal best: top athletes and singers have

coaches. Should you? Available at: http://www.newyorker.com/

magazine/2011/10/03/personal-best. Accessed January 8, 2015.

7. Singer AJ, Arora B, Dagum A, Valentine S, Hollander JE.

Development and validation of a novel scar evaluation scale.

Plast Reconstr Surg. 2007;120:1892-1897.

8. Verhaegen PD, van der Wal MB, Middelkoop E, van Zuijlen PP.

Objective scar assessment tools: a clinimetric appraisal. Plast

Reconstr Surg. 2011;127:1561-1570.

9. Bloemen MC, van Gerven MS, van der Wal MB, Verhaegen PD,

Middelkoop E. An objective device for measuring surface rough-

ness of skin and scars. J Am Acad Dermatol. 2011;64:706-715.

10. Ogawa R. Mechanobiology of scarring. Wound Repair Regen.

2011;19(suppl 1):S2-S9.

11. Ogawa R, Akaishi S, Huang C, et al. Clinical applications of

basic research that shows reducing skin tension could

prevent and treat abnormal scarring: the importance of

fascial/subcutaneous tensile reduction sutures and flap

surgery for keloid and hypertrophic scar reconstruction.

J Nippon Med Sch. 2011;78:68-76.

12. Martin D, Umraw N, Gomez M, Cartotto R. Changes in

subjective vs objective burn scar assessment over time: does

the patient agree with what we think? J Burn Care Rehabil.

2003;24:239-244.

13. Zitelli JA. TIPS for a better ellipse. J Am Acad Dermatol. 1990;

22:101-103.

14. Kantor J. The fascial plication suture: an adjunct to layered

wound closure. Arch Dermatol. 2009;145:1454-1456.

15. Pearl RM, Johnson D. The vascular supply to the skin: an

anatomical and physiological reappraisal—part I. Ann Plast

Surg. 1983;11:99-105.

16. Daniel RKC. The anatomy and hemodynamics of the

cutaneous circulation and their influence on skin flap design.

Boston: Little, Brown, & Co; 1975.

17. Cutting C. Critical closing and perfusion pressures in flap

survival. Ann Plast Surg. 1982;9:524.

18. Cutting C, Ballantyne D, Shaw W, Converse JM. Critical closing

pressure, local perfusion pressure, and the failing skin flap.

Ann Plast Surg. 1982;8:504-509.

19. Zitelli JA, Moy RL. Buried vertical mattress suture. J Dermatol

Surg Oncol. 1989;15:17-19.

20. Boyer JD, Zitelli JA, Brodland DG. Undermining in cutaneous

surgery. Dermatol Surg. 2001;27:75-78.

Answers to CME examination

Identification No. JA0315

March 2015 issue of the Journal of the American Academy of Dermatology.

Miller CJ, Antunes MB, Sobanko JF. J Am Acad Dermatol 2015;72:388.

1. c2. b