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Facial plastic surgery FPS 2004 Czerwinski.pdf

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Traumatic Arch Injury: Indications and an Endoscopic Method of Repair Marcin Czerwinski, M.D. 1 and Chen Lee, M.D., M.Sc., F.R.C.S.C., F.A.C.S. 1 ABSTRACT The unique strategic position of the zygomatic arch makes it an important surgical landmark in facial fracture repair. Because of the numerous negative sequelae associated with the traditional coronal approach to the arch, it has frequently been omitted as a point of reduction and fixation. Endoscope-assisted repair allo
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   Traumatic Arch Injury: Indications and anEndoscopic Method of Repair Marcin Czerwinski, M.D. 1 and Chen Lee, M.D., M.Sc., F.R.C.S.C., F.A.C.S. 1 ABSTRACT  The unique strategic position of the zygomatic arch makes it an important surgicallandmark in facial fracture repair. Because of the numerous negative sequelae associated with the traditional coronal approach to the arch, it has frequently been omitted as a pointof reduction and fixation. Endoscope-assisted repair allows accurate zygomatic archrestoration without the setbacks of coronal access. The indications for arch repair includemarkedly displaced isolated arch fractures, complex zygoma fractures with arch comminu-tion, and Le Fort III level fractures. In complex zygoma fractures, the arch helps accurately restore midface projection and width and serves as an additional stable anchor point. In LeFort III fractures, restoration and fixation of the arch are essential components of the repairnecessary to stabilize the maxillary dentition to the cranial base. Endoscopic arch repair is anovel, technically challenging procedure that requires a different set of surgical skills andconsiderable training. Implementation of appropriate teaching programs and furtheradvances in instrument development will overcome the steep learning curve associated with this technique and encourage its use. KEYWORDS:  Zygomatic arch, endoscope, Le Fort III REGIONAL ANATOMY  The zygomatic arch is a narrow, laterally positionedelement of the craniofacial skeleton that has aconsistent structure and symmetry. In the axial plane,the shape of the arch changes from a curved posteriorthird to straight middle and anterior thirds. In thesagittal plane the arch is parallel to the Frankforthorizontal. The arch is strategically positioned joiningthe zygoma and the rest of midface to the stablecranial base. Thus, it is a potentially importantlandmark in the restoration of normal facial anatomy following traumatic injury to the structures adjoiningit. 1,2  The length and shape of the arch in the axialplane and its angulation from the sagittal plane canbe used to reestablish accurate projection and width of the face. Thorough knowledge of the regional soft tissueanatomy and of its relationship with the frontal branchof the facial nerve is essential to avoid injury during archexposure. The nerve pierces the superficial musculoapo-neurotic system at the lower border of the zygomaticarch and courses superficially to the temporoparietalfascia in an anterosuperior direction. 3  The coronal inci-sion has been used traditionally to reach the arch(Fig. 1). The disadvantages associated with a coronalincision have discouraged many surgeons from archrepair. We introduce a novel endoscopic method of arch repair with low risk of transection to the frontalbranch of the facial nerve (cranial nerve [CN] VII). Current Considerations in Endoscopic Facial Plastic and Reconstructive Surgery; Editors in Chief, Fred Fedok, M.D., Gilbert J. Nolst Trenite,M.D., Ph.D., Daniel G. Becker, M.D., Roberta Gausas, M.D.; Guest Editor, James C. Alex, M.D.  Facial Plastic Surgery  , Volume 20, Number 3,2004. Address for correspondence and reprint requests: Chen Lee, M.D., M.Sc., F.R.C.S.C., F.A.C.S., Chairman, Division of Plastic Surgery,Associate Professor, McGill University, Montreal General Hospital, D6.269, 1650 Cedar Avenue, Montreal (Quebec), Canada H3G 1A4. 1 Division of Plastic Surgery, Department of Surgery, McGill University Health Center, McGill University, Montreal, Quebec, Canada. Copyright # 2004 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001 USA. Tel: +1(212) 584-4662. 0736-6825,p;2004,20,03,231,238,ftx,en;fps00518x. 231  TRAUMATIC INJURY PATTERNSOF THE ARCH Fracture displacement of the arch is determined by thedirection of the traumatic force and pull of the attachedmasseter muscle. Three common patterns of arch injury occur. First, a direct lateral impact fractures and displacesthe arch medially (Fig. 2). Second, posterior telescopingof the arch can result from a frontal impact to the malarprominence (Fig. 3). Third, lateral arch displacement isless common and results from an anterior force vector tothe malar prominence with the energy dissipated at thearch through an explosive burst with lateral displacementof the comminuted arch fracture segments (Fig. 4A).Recognition of this fracture pattern is important asreduction attempts with lateral force applied under thearch as described by Gillies and Keen further exacerbatethe degree of fracture displacement. The clinical patterns of presentation include iso-lated fractures of the zygomatic arch with temporaldepression, especially in patients with a prominent pre-injury arch contour. A zygoma fracture results fromfracture disruption of all its normal bone attachmentsto the cranial base. Because arch disruption is a necessary component of a displaced zygomatic fracture, inclusionof arch repair may enhance reduction and stability of acomplex zygomatic fracture. 4,5  The mobile maxilla of aLe Fort III level fracture is defined partially by thefracture separation of the maxilla from the cranial baseat the arch. 6 Repair necessitates reduction and stabiliza-tion at this cranial buttress. EFFECT OF ARCH REPAIR ONTREATMENT OUTCOME  The arch has frequently been omitted as a point of reduction and fixation. In contradistinction, anatomicfracture repair using open methods of reduction andinternal rigid fixation are the accepted current standardsin the operative management of most facial fractures. This general disregard for arch restoration may havearisen because of the disadvantages associated with thetraditional coronal approach to arch repair. An extensivescalp incision and dissection has been traditionally necessary with coronal arch repair. This exposure intro-duces risk of temporal hollowing, weakness or perma-nent paralysis of the frontal branch of the facial nerve,alopecia, loss of sensation posterior to the incision,excessive blood loss, and a lengthy operative time. 7  Thus, the potential role of the arch as a foundationlandmark has been neglected.In isolated arch fractures, accurate visual reduc-tion reestablishes the preinjury contour of the lateralface. Stabilization prevents redisplacement due toreinjury or pull of the masseter muscle, an issue notaddressed by the often used Gillies approach. Anatomicrepair is especially important in patients with prominentarches, where the normal soft tissues may not hide theunderlying bone discrepancies. Figure 1  Open reduction and rigid miniplate fixation of the archhave traditionally required an extensive coronal scalp incision. Figure 2  Three patterns of comminuted arch injury are com-monly observed. Medial arch displacement often results from adirect lateral impact. Figure 3  Posterior telescoping of the arch occurs secondary toan anterior impact to the malar prominence. 232  FACIAL PLASTIC SURGERY/VOLUME 20, NUMBER 3 2004  In complex zygoma fractures, restoration of srcinal arch shape, length, and angulation facilitatesan accurate reestablishment of midfacial projectionand width. The arch serves a secondary role as a pointof added fracture stabilization.In associated Le Fort III fractures, the arch rigidly suspends the mobile midface segment to the cranial baseand stabilizes the maxillary dentition. Here as well, thearch is important in restoration of accurate midfacialprojection and width. To benefit from the advantages of arch repairand simultaneously minimize surgical stigmata of cor-onal exposure, we have developed an endoscope-assistedtechnique. EVOLUTION OF ENDOSCOPICREPAIR OF THE ARCH In the laboratory, we evaluated the effectiveness of theendoscope to reduce and fixate the arch precisely andavoid facial nerve injury on a cadaver fracture model.Using remote minimal access incisions, excellent fracturereduction and rigid miniplate stabilization were achievedby endoscopically assisted fracture repair in all cadaverskulls. Dissections of the frontal branch of the facialnerve confirmed complete anatomic continuity in allspecimens. 7 Subsequently, we have used the endoscopic ap-proach to zygomatic arch repair in 25 clinical cases. 8 Of those, 3 were isolated arch fractures, 15 were associated with zygoma fractures, and 7 involved Le Fort IIIfractures (Fig. 5). All patients demonstrated excellentreestablishment of facial width and projection, as con-firmed by facial computed tomography scans. No per-manent dysfunction of the frontal branch of CN VIIoccurred in our series. Temporary palsies, probably caused by aggressive traction, were present in 4 of 7 LeFort III, 3 of 15 complex zygoma, and 1 of 3 isolatedzygomatic arch fractures. Operating times for endo-scope-assisted repairs were 2.0 hours for the isolatedarch, 4.9 hours with complex zygoma, and 9.7 hours forthe Le Fort III fractures (Fig. 6). SURGICAL TECHNIQUE Endoscopic Equipment  The endoscope used at this center is a 4-mm-diameter,30-degree angle scope (Karl Storz, Germany). To Figure 4  (A) Lateral arch displacement is the least common fracture pattern described. However, its recognition is important as mosttechniquesof fracturereductionemploya lateralforcetothedisplacedarchsegment. Applicationof suchlateralizingtechniquesof archrepair to an already laterally displaced arch only exacerbates the degree of fracture displacement. (B) Anatomic repair of the lateralizedarchwassuccessfullyaccomplishedwithendoscopicassistance.RefertoFigure8toseeassociatedclinicalphotographsofthispatient. Figure 5  The arch components of fractures were repairedendoscopically in isolated arch, complex zygoma, and Le Fort IIIinjuries. TRAUMATIC ARCH INJURY / CZERWINSKI, LEE  233  maintain an optical cavity and stabilize the orientation of the endoscope simultaneously, a 4-mm endoscope-mounted retractor (Isse Dissector Retractor, Karl Storz,Germany) is required. The Olympus Video System(Olympus America, Lake Success, N.Y.) is used to pro- ject the endoscopic image to a video display. Exposure A preauricular incision at the anterior margin of thehelical crus, extending superiorly 2 cm above the auricle,is made. This incision is carried through the skin andthe temporoparietal fascia to expose the deep temporalfascia. To create an adequate optical cavity, a periostealelevator is used to dissect superficial to the deep temporalfascia. To avoid injury to the frontal branch of thefacial nerve, the nonendoscopic component of the dis-section does not extend below an imaginary line joiningthe helical crus and the superior orbital rim. Followingdissection of the optical cavity, the retractor-mountedendoscope is inserted in the plane superficial to the deeptemporal fascia and visualized dissection is performeddown to the zygomatic arch (Fig. 7A, B). Temporalhollowing is avoided by maintaining the integrity of the deep temporal fascia. Once the arch is reached, theperiosteum is incised and the dissection is carried in thesubperiosteal plane to expose the entire zygomatic archand identify all sites of fracture. Reduction Commonly, reduction of the arch is performed in situ. The fracture segments are aligned, according to thefragmentation pattern, to restore the preinjury form of the arch. When the comminution is severe and results ina highly unstable pattern, the fracture segments can beremoved from the operative field, stripped of attachedsoft tissues, and reduced on a side table. The lattermethod, however, suffers from an increased rate of postoperative bone resorption because of the interrup-tion of the periosteal blood supply. 9 Fixation A short miniplate (in isolated zygomatic arch fractures)or a long miniadaptation plate (in associated midfacefractures) is plated onto the arch in situ or on a side table. The long miniadaptation plate extends onto the lateralorbital rim, restoring and rigidly fixing midface anatomy.Following confirmation of accurate alignment at allfracture sites and accurate arch positioning, the plate isanchored, under endoscopic guidance, with screw fixa-tion (Fig. 7C). SEQUENCING OF COMPLEX REPAIRS  With complex facial fractures, multiple sites of fracturerepair may be necessary to achieve accurate restoration of preinjury facial form. When arch restitution is an im-portant component of the repair, we have found thefollowing sequences of fracture reduction and fixation tobe most accurate and expedient. Complex Zygoma Anatomic repair of complex zygomatic fractures may require reduction and fixation at all the major fractureinterfaces. This includes the zygomaticofrontal suture,infraorbital rim, zygomaticomaxillary buttress, and thezygomatic arch. We have found repair most facile when the zygomaticofrontal suture and infraorbital rimare reduced and fixated first. This serves to restore theexternal skeletal frame of the orbit. Next, accurateprojection of the orbital frame is achieved by repairingthe arch. Last, the fracture at the zygomaticomaxillary buttress is addressed. Le Fort III Le Fort III level fracture requires reduction and fixationof the midface to the cranial base to provide a stableplatform for dental occlusion. Repair is most expeditiousif the cranio-orbital and maxillomandibular units arerestored separately and then joined at the Le Fort I level. The cranio-orbital unit is repaired by reduction andfixation at the frontozygomatic suture and infraorbitalrim to recreate the orbital frame. Accurate projection of the orbital frame is established through arch repair. Themaxillomandibular unit is restored using maxilloman-dibular fixation. Last, the cranio-orbital and maxillo-mandibular units are joined by rigid fixation of theanterior buttresses of the maxilla. Figure6  Mean operativetimes of endoscope-assistedrepair offacial fractures involving the zygomatic arch. The length ofsurgery correlates well with the complexity of injury. 234  FACIAL PLASTIC SURGERY/VOLUME 20, NUMBER 3 2004

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