técnica de dissecção temporal que impede esvaziamento temporal na abordagem coronal - 2009

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Copyright @ 200 9 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

Temporal Dissection Technique That Prevents TemporalHollowing in Coronal Approach

Rong-Min Baek, MD, Chan Yeong Heo, MD, and Sang Woo Lee, MD

Abstract: Temporal hollowing after lateral facial skeletal exposurevia a coronal approach is not uncommon. This is caused by injury tothe supercial temporal fat pad. However, to prevent facial nerveinjury at the zygomatic arch, incision of the supercial layer of thetemporalis fascia (TF) and exposure of the temporal fat pad areaccompanied with most coronal approaches. Here we introduce our method of dissection of the suprasupercial layer of the TF without exposure of the temporal fat pad and report on its safety and efcacy.

Temporal dissection just supercial to the supercial layer of theTF was performed to the superior border of the zygomatic arch.After identifying the zygomatic arch, an incision was made at the posterosuperior aspect of the arch, when exposure of the arch wasnecessary for access to the lateral skeleton.

From 1989 to 2008, 522 patients undergoing craniofacial surgeryvia coronal approach were analyzed retrospectively. No patient developed temporal hollowing. However, 14 patients (2.7%)developed frontal weakness immediately postoperatively, and 2 of them had permanent paresis. The frequency of this motor morbiditywas low compared with that of other reports.

Preservation of the temporal fat pad in coronal approach isessential for the prevention of temporal hollowing, and for this, werecommend suprasupercial layer of TF dissection.

Key Words: Coronal approach, temporal hollowing, temporaldissection

( J Craniofac Surg 2009;20: 748 Y 751)

The coronal incision is a common surgical approach for access tothe upper and lateral parts of the facial skeleton duringcraniofacial surgery. A serious complication, associated with thisapproach, is frontal weakness due to injury of the frontal nerve at thetemporal region. The incidence of temporary frontal weakness has been reported to be between 8% and 22% of cases undergoing this procedure.

1 Y 4Most cases improve by the end of 1 year; however,

permanent palsy has been reported in up to 2% of cases. 1 Y 4 To

protect the frontal nerve, subfascial dissection under the supercial

layer of the temporalis fascia (TF) is performed. During this standard dissection, interference with the supercial temporal fat pad isinevitable.

Intratemporal fat pad dissection might injure the fat pad and result in temporal hollowing, which is a signicant cosmeticcomplication (Fig. 1). The cause of temporal hollowing is temporalfat pad atrophy from ischemia, denervation, or displacement that occurs as a result of dissection through the fat pad.

5 Y 7Therefore, this

complication could be prevented if the dissection was performed without interfering with the temporal fat pad, that is, if a su-

prasupercial layer TF dissection was performed.In this article, we introduce our dissection method for thetemporal area to prevent temporal hollowing; we discuss the safetyof this procedure with regard to frontal nerve injury. Furthermore,we added an incision line and location that are suitable for hidingscars.

PATIENTS AND METHODS

PatientsFrom 1989 to 2008, 522 patients with craniomaxillofacial

disorders underwent operations with a coronal approach by 2surgeons in our department (Table 1). The mean age of the patientswas 32.0 years (range, 4 months to 71 years). The mean follow-up

period was 42 months (range, 6 Y

98 months).Incision

A rectilinear gure-of- BW[ incision was placed (Fig. 2). Themidpoint of the W had to be behind the hairline, more than 8 cm inadults. If closer than this, the scar could be visualized. To expose thelateral skeleton, we did not have to perform a preauricular incision.

FIGURE 1. This patient underwent surgery for trauma via thecoronal approach by an inexperienced surgeon, and temporalhollowing occurred. Frontal view (left) and right 3-quarter view (right).

ORIGINAL ARTICLE

748 The Journal of Craniofacial Surgery &

Volume 20, Number 3, May 2009

From the Department of Plastic and Reconstructive Surgery, Seoul NationalUniversity College of Medicine, Seoul, Korea.Received November 20, 2008.Accepted for publication January 4, 2009.Address correspondence and reprint requests to Sang Woo Lee, MD,

Department of Plastic and Reconstructive Surgery, Seoul NationalUniversity College of Medicine, Seoul National University BundangHospital, 166 Gumiro, Bundang, Seongnam, Gyeonggi, 463-707, Korea;E-mail: [email protected]

The authors received no nancial support from any company or sources and have no commercial association or nancial relationships to disclose.

Copyright * 2009 by Mutaz B. Habal, MDISSN: 1049-2275DOI: 10.1097/SCS.0b013e3181a2d745


2/4Copyright @ 200 9 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.

Rather, we made a small triangular ap above the auricle. This aided not only in hiding the scar but also in preserving the supercialtemporal artery (Fig. 3). Next, the anterior and posterior hair wasgathered separately with small elastic bands. The braided hair,anterior and posterior to the planned incision site, plays an important role as handles for pulling the scalp, which reduces bleeding and

minimizes damage to the hair follicles.Dissection

A subgaleal dissection to the supraorbital area was performed using a blade. In the temporal area, an incision was made abovethe supercial layer of the TF, and dissection was carried down tothe zygomatic arch between the temporoparietal fascia and thesupercial layer of the TF. The layer between the temporoparietalfascia and the supercial layer of the TF can be dissected clearly and easily because this loose areolar layer is almost avascular, potentiallayer with the exception of 1sentinel vein and 1 to 3 perforator vessels on each side, which pass downward from the overlyinggaleal vessels and course 1 cm above the zygomatic arch and the

TABLE 1. Diagnosis of Patients

Diagnosis No. Patients (%)

Wide malar complex* 174 (33.3)Aging face 160 (30.6)Zygomatic fracture 85 (16.3)Craniosynostosis 35 (6.7)Crouzon disease 29 (5.6)Hypertelorism 14 (2.7)Others 25 (4.8)Total 522 (100.0)

*These patients underwent reduction malarplasty with the coronalapproach for aesthetic purpose V this type of operation is popular in Korea.

Only patients with accompanying lateral facial skeleton exposure(subperiosteal midface lift) were included.

FIGURE 2. Left, Design of the coronal incision line from the vertex. Points T, V, and O stand for the trichion, vertex, and occiput,respectively. Points A and B are the points most receded from the hairline. The lengths of lines TV, AA

, and BB

are equivalentor longer than 8 cm. Points A

and B

are spots 2 cm above the upper attachment of the auricular helix. The vertex view(middle) and lateral view (right) after gathering of the hair.

FIGURE 3. Left, The relationship between Coronal incision line (a thick line) and the supercial temporal artery (dotted lines).The distance a from the ear attachment to the supercial temporal artery was 1.39 cm, and the distance b from the point2 cm above the ear attachment and the parietal branch of the supercial temporal artery was 1.54 cm. 8 Therefore, the frontalbranch (F) and proximal part of the parietal branch (P) of the supercial temporal artery were never disrupted by our incisionline. Right, Intraoperative view.

The Journal of Craniofacial Surgery & Volume 20, Number 3, May 2009 Temporal Dissection in Coronal Approach

* 2009 Mutaz B. Habal, MD 749



lateral orbital rim (Fig. 4). 9 Once these sentinel veins and perforator vessels were isolated and cauterized, dissection was continued inferiorly to the zygomatic arch while preserving the integrity of thesupercial layer of the TF V without any exposure of the supercialtemporal fat pad (Fig. 5). A safe access route to the zygomatic archcould be guaranteed by this method of sharp dissection, because the

frontal branch of the facial nerve always courses along theundersurface of the temporoparietal fascia. A sharp incision wasthen made through the periosteum on the posterosuperior surface of the zygomatic arch, and full exposure of the lateral facial skeletonwas achieved (Fig. 6).

Whenever the temporalis muscle is dissected or elevated fromthe temporal fossa, a plan should be made to reinsert it into theoriginal position before manipulation should be prepared. An easymethod involves (1) drilling holes through the posterior edge of theorbital rim and suturing the anterior edge of the temporalis musclewith absorbable sutures and (2) sparing 5 mm in width of theinsertion part of the TF attached to the temporal crest during theelevation then suturing this portion to the dissected temporal muscle.

RESULTS

Particular attention was directed to the search for evidence of temporal contour deformity, sensory and motor decit, and scarring

FIGURE 4. One sentinel vein (white arrow) and 3 perforator vessels (black arrows) at the left temporal area pass downward

from the overlying galeal vessels and course 1 cm above thezygomatic arch and the lateral orbital rim.

FIGURE 5. Left, Schematic cross-sectional diagram of the dissection approach to the zygomatic arch (red line). Note in thisdiagram that the supercial temporal fat pad, middle temporal artery, and frontal temporal branch of the facial nerve are notdisrupted. Right, Dissection to the zygomatic arch could be achieved without penetration of supercial temporal fat pad.S indicates skull; T, temporalis muscle; Z, zygomatic arch; TF, supercial layer of TF.

FIGURE 6. Left, The incision of the periosteum on the zygomatic arch was located at the posterosuperior aspect of the arch(black line). Right, The zygomatic arch was fully exposed preserving the continuity of the supercial layer of the TF.Z indicates zygomatic arch; TF, supercial layer of temporalis fascia.

Baek et al The Journal of Craniofacial Surgery & Volume 20, Number 3, May 2009

750 * 2009 Mutaz B. Habal, MD



and loss of hair on the incision site (Table 2). There were no ndingsto suggest temporal hollowing Y diminished volume or displacement of the supercial temporal fat pad and atrophy or disinsertion of thetemporalis muscle. A little loss of hair at the incision line wasinevitable; 7 patients showed widening of the scar along the incisionline. These scars were revised with good results. Seventeen patientshad immediate postoperative anesthesia or paresthesia at the

supraorbital region. However, all of these patients returned tonormal sensation within a year. Fourteen patients (2.7%) developed postoperative frontal weakness, and most resolved in 1 year;however, 2 patients had continued weakness. The 2 patients with a permanent frontal nerve injury underwent surgery because of a facial bone fracture. Because of the displaced zygomatic arch, the nervewas likely transected during the dissection.

DISCUSSIONTemporal hollowing is dened as a concavity or depression of

the temporal region located superior to the zygomatic arch and immediately posterior to the lateral orbital rim. The exact cause of temporal hollowing is unknown. Possible causes include atrophy of the supercial temporal fat pad or temporalis muscle. However, if reattachment of the temporalis muscle is performed properly, adisinsertion or an atrophy of the temporalis muscle is unlikely to bethe cause. Lacey et al 7 reported that diminution or displacement of the temporal fat pad caused temporal hollowing (not by atrophy or disinsertion of the muscle).

Temporal fat pad atrophy or prolapse can occur by disruptionof the suspensory system of the supercial temporal fat pad, which isadherent supercially; therefore, it is inevitably injured by dissection below the supercial layer of the TF. 6 Other mechanisms of the fat pad injury include vascular injury or a nerve injury in the fat pad.Disruption of the middle and deep temporal arteries as well aszygomaticotemporal nerve damage can cause atrophy of thetemporal fat pad. However, all of these possibilities can be prevented if intra Y fat-pad dissection is not performed.

The occurrence rate of temporal hollowing has been reported in up to 6% of the cases.

1Most of articles do not report on the

temporal hollowing, and the actual rate might have been under-reported. However, this complication is permanent and a signicant cosmetic deformity. Therefore, the subsupercial layer of the TFdissection should be avoided. Our method was associated with a lowfrequency of injury to the frontal nerve compared with other reports. 1

Y 4 In the 2 cases with permanent palsy, we did not think thenerve could be protected, if dissected through the fat pad (thisoccurred because of our mistake in identifying the right plane with aseverely displaced zygomatic arch). However, the dissection just above the zygomatic arch has to be carefully performed with the

blade in the downward direction, and extensive traction of the ap inthis region has to be avoided.

In this study, the number of patients with sensory problemmight be underestimated because preoperatively all the patients werefully explained about the sensory complications and its course; thus,they did not think of this situation seriously. The minor complica-

tions such as numbness at the incision site or a small widened scar were not evaluated in this study because we analyzed patients bychart review only. Minor complaints were not included in themedical record. The actual percentage of other complications might be slightly higher than recorded. This is because, for example, wedid not examine the infants with craniofacial anomalies after surgery, and some complications could have been missed or not documented in the charts reviewed. However, the major complica-tions such as motor palsy or temporal hollowing were unlikely to bemissed, and except for patients younger than 10 years (n = 103), themajor complication rate was not higher than that reported previously.

In our experience, a preauricular extension of the incision isnot necessary for the coronal approach. We could fully expose thelateral skeleton without any extension of the incision. Rather, weused a small triangular ap just above the auricle. This ap provided

some advantages; it could remain better camouaged and perhapscould be revised more easily, and provides bloodless dissection inthis area because of the avoidance of the supercial temporalartery. 10

Between 1989 and 2008, 522 patients underwent craniofacialsurgery with our coronal approach technique that prevented thedevelopment of temporal contour deformities. Based on our results,the suprasupercial layer of the TF dissection was a safe and cosmetically acceptable method for coronal approach.

ACKNOWLEDGMENT

The authors thank Se-Min Baek, MD, who provided mentor- ship and inspiration for this article.

REFERENCES1. Frodel JL, Marentette LJ. The coronal approach. Anatomic and technical

considerations and morbidity. Arch Otolaryngol Head Neck Surg 1993;119:201 Y 207

2. Kerawala CJ, Grime RJ, Stassen LF, et al. The bicoronal flap(craniofacial access): an audit of morbidity and a proposed surgicalmodification in male pattern baldness. Br J Oral Maxillofac Surg 2000;38:441 Y 444

3. Shumrick KA, Kersten RC, Kulwin DR, et al. Extended access/internalapproaches for the management of facial trauma. Arch Otolaryngol Head Neck Surg 1992;118:1105 Y 1112

4. Mitchell DA, Barnard NA, Bainton R. An audit of 50 bitemporal flaps in primary facial trauma. J Craniomaxillofac Surg 1993;21:279 Y 283

5. Matic DB, Kim S. Temporal hollowing following coronal incision: a prospective, randomized, controlled trial. Plast Reconstr Surg 2008;121:379e Y 385e

6. Kim S, Matic DB. The anatomy of temporal hollowing: the superficialtemporal fat pad. J Craniofac Surg 2005;16:760 Y 7637. Lacey M, Antonyshyn O, MacGregor JH. Temporal contour deformity

after coronal flap elevation: an anatomical study. J Craniofac Surg 1994;5:223 Y 227

8. Stock AL, Collins HP, Davidson TM. Anatomy of the superficialtemporal artery. Head Neck Surg 1980;2:466 Y 469

9. Tolhurst DE, Carstens MH, Greco RJ, et al. The surgical anatomy of thescalp. Plast Reconstr Surg 1991;87:603 Y 612

10. Posnick JC, Goldstein JA, Clokie C. Advantages of the postauricular coronal incision. Ann Plast Surg 1992;29:114 Y 116

TABLE 2. Complications Associated With Our Coronal Approach

Complications No. Patients (%)

Temporal hollowing 0 (0)

Scar with alopecia needing revision 7 (1.3)Sensory deficit 17 (3.3)Facial nerve motor deficit (temporary) 14 (2.7)Facial nerve motor deficit (permanent) 2 (0.4)Total 522 (100)

The Journal of Craniofacial Surgery & Volume 20, Number 3, May 2009 Temporal Dissection in Coronal Approach

* 2009 Mutaz B. Habal, MD 751

técnica de dissecção temporal que impede esvaziamento temporal na abordagem coronal - 2009

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