------------------------------------------------------------------------------- TITLE: ZYGOMATIC FRACTURES SOURCE: Dept. of Otolaryngology, UTMB, Grand Rounds DATE: October 132, 1994 RESIDENT PHYSICIAN: Christopher P. Thompson, M.D. FACULTY: Hadi Seikaly, M.D. DATABASE ADMINISTRATOR: Melinda McCracken, M.S. ------------------------------------------------------------------------------- "This material was prepared by resident physicians in partial fulfillment of educational requirements established for the Postgraduate Training Program of the UTMB Department of Otolaryngology/Head and Neck Surgery and was not intended for clinical use in its present form. It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion." I. Introduction - Outline A. Epidemiology B. Anatomy C. Fracture Patterns and Classification D. Clinical Exam E. Radiography F. Medical Treatment G. Reduction Techniques H. Surgical Approaches I. Fixation Techniques II. Zygomatic complex fractures A. Epidemiology 1. frequent - in some studies these are the most common facial fractures and in others they are second, behind nasal fractures 2. male predilection 4:1 3. most often in the second and third decades 4. etiology according to a recent study by Covington et.al. demonstrated that about 80% were caused by motor vehicle- related traumas with the remaining 20% split between altercations and falls a. bilateral fractures occur in MVA's b. left zygomatic complex fractures most common in altercations c. the incidence in this study decreased by 50% between 1979 and 1989 possibly due to seat belt use B. Anatomy 1. important functionally and cosmetically a. forms the zygomatic buttress responsible for resisting vertical stresses (occlusal) as well as contributing to the horizontal buttress in this area b. contributes to the orbital floor and lateral wall which is important to remember because displaced fractures will result in a displaced orbital floor c. point of greatest prominence on the cheek arises at the intersection between the vertical arc and the horizontal arc (Frankfurt horizontal) 2. roughly pyramidal in shape a. articulates with frontal, sphenoid, maxillary, and temporal bones b. articulating bones are much weaker and account for the infrequency of zygomatic body fractures 3. provides an origin to much of the masseter muscle and to the temporalis fascia C. Fracture Patterns 1. nomenclature a. technically incorrect terms include tripod and trimalar fracture b. more accepted terms are zygomatic complex and malar fractures 2. three fracture lines radiate from the inferior orbital fissure a. anteromedial - connects the fissure to the infraorbital foramen and at the infraorbital rim the fracture travels under the zygomatic buttress b. inferior - runs from the fissure inferiorly through the infratemporal maxilla and joins the anterior fracture c. superolaterally - from the fissure along the lateral orbital wall usually separating the zygomatic-sphenoid suture line 3. zygomatic complex fractures usually have an additional fracture through the zygomatic arch a. occurs approximately 1.5 cm posterior to the zygomatic- temporal suture line when single b. often three fracture lines through the arch will produce two free bone segments 4. these are patterns of fractures, but there are an infinite number of ways such a fracture can occur D. Fracture Classification 1. there are between ten and twenty ZMC fracture classifications based on plain radiographs a. most are divided into displaced and nondisplaced fractures or isolated zygomatic arch fractures b. none are universally accepted 2. Fujii and Yamashiro in 1983 used the CT to classify these fractures a. type I - no displacement b. type II - isolated arch fx c. type III - no rotation in the antero-posterior direction d. type IV - rotation in the antero-posterior direction e. this scheme has also met with poor acceptance E. Clinical Exam 1. Eye a. first priority after ABC's and neurologic exam b. 5% of zygomatic complex fractures were associated with vitreous hemorrhage, hyphema, globe laceration, optic nerve damage, or corneal abrasion in a study by Livingston; who also indicated that consultation should be obtained only in those patients with suspected eye trauma c. subconjunctival ecchymosis - 50-70% of cases d. displacement of palpebral fissure (figure 4) - the lateral palpebral ligament is attached to the zygoma so that displacement will carry the lateral canthus with it (antimongoloid slant) e. unequal pupillary level - disruption of the orbital floor and subsequent displacement of Tenon's capsule will lower the pupillary level f. diplopia i. monocular diplopia requires immediate ophthalmologic consultation, as it indicates a traumatic globe injury ii. binocular diplopia occurs in 10 - 40% of zygomatic injuries and may be the result of entrapment, neuromuscular injury, hematoma, or change in orbital shape iii. forced duction test done by grasping the inferior rectus through the conjunctiva, and when positive usually indicates an inability to rotate the globe superiorly because of orbital floor entrapment g. enophthalmus i. a result of an increase in the orbital volume due to displacement of the zygoma, or by disruption of the inferior and lateral orbital walls ii. clinically evident when edema dissipates and causes an accentuation of the upper lid sulcus, narrowing of the palpebral fissure, and pseudoptosis of the upper lid 2. Zygoma a. superior view is the most useful b. index fingers placed below the infraorbital rims into the edematous tissues c. palpate for malar depression - occurs in 70-86% of cases which will illicit pain when fractured d. palpate for arch fractures as well as a step-off deformity at the infraorbital rim 3. Oral cavity a. ecchymoses in the maxillary buccal sulcus often occurs with even a small disruption of the anterior or lateral maxilla b. irregularities in the normally smooth contour of the zygomatic buttress of the maxilla can often be palpated through the oral cavity c. trismus accompanies zygomatic fractures in approximately one third of cases and is due either to impingement of the translating coronoid process or a muscle spasm secondary to impingement of the displaced fragments 4. Nose/Sinuses a. epistaxis is unilateral in 30 - 50% of unilateral zygomatic injuries and is due to tearing of the maxillary sinus mucosa b. crepitance in the facial soft tissues will result when air from the maxillary sinuses escapes through a mucosal tear 5. Neurologic symptoms & signs a. pain - unless there is mobility, severe pain is not usually a feature b. infraorbital paresthesia is present in about 50 - 90% of injuries and is more common in fractures that are displaced i. paresthesia of the lower eyelid, upper lip, and lateral nose ii. Taicher et.al. compared method of fracture repair to residual infraorbital nerve disturbance at one year and found that the best result was with miniplate osteosynthesis at only 25% F. Radiographic Evaluation 1. plain films - two standard views have been used, but a number of others exist a. posteroanterior oblique view (Waters view) is done so that the petrous ridge is inferior to the maxillary sinus b. submental vertex (bucket-handle, skull axial) performed with the head in flexion isolating the zygomatic arches c. other views include orbital, Caldwell, lateral skull, and panorex, but they do not provide much additional information 2. CT scans have been the standard of care in significant facial fractures because at least 50% of these patients will have concomitant intracranial injury. a. the usual protocol for rapid assessment of craniofacial trauma includes 5 mm axial slices from the hard palate through the posterior fossa, followed by 10 mm axial slices to the skull vertex b. a CT of the facial bones can then be performed with 3mm sections and includes a series of coronal cuts if the patient can tolerate the neck extension c. according to the study by Covington the need for orbital floor repair has declined from 90% to 30%, which he attributes to the improved imaging afforded by CT d. three-dimensional CT scans were compared with conventional two-dimensional CTs in 1993 by Broumand et.al. who found that there was no improvement in the accuracy of interpretations with the addition of 3-D CT G. Medical Treatment - Edward Ellis writes in Fonseca's Oral and Maxillofacial Trauma book that "The fractured zygoma is perhaps the least understood and most frequently mistreated facial fracture." 1. antibiotics a. despite the extremely low incidence of infection, and the lack of controlled studies documenting effectiveness, many surgeons advocate the use of prophylactic antibiotics b. the theoretical route of infection development is via the violated maxillary sinus mucosa 2. observation a. many zygomatic fractures are nondisplaced or minimally displaced, in which case intervention is not necessary b. Covington's study indicated that 30% of zygomatic injuries required no surgical intervention which agrees with the past literature's numbers of between 9 and 50%. H. Reduction 1. virtually all displaced zygomatic fractures should be reduced 2. controversy arises concerning the need for closed reduction versus open reduction followed by fixation a. proponents of fixation for all displaced fractures theorize that the pull of the masseter muscle will disrupt the alignment in a non-fixed zygoma b. studies such as that by Larsen demonstrate excellent long term results in patients treated with reduction only, which would indicate that the masseteric pull may not be clinically significant c. it is universally agreed upon that the ends of the fractured segment are less likely to maintain a reduction if there is comminution, and that this is demonstrated radiographically by wide separation of the fracture lines 3. reduction techniques a. temporal approach (Gillies) - useful in the reduction of both isolated arch fractures and zygomatic complex fractures i. skin incision made 2.5cm superior and 2.5cm anterior to the helix and carried down to the temporalis fascia ii. the fascia is incised and a periosteal elevator is advanced inferiorly until the medial surface of the arch and temporal surface of the zygomatic body are identified iii. the Rowe zygomatic elevator is inserted and used to perform the reduction b. buccal sulcus approach i. a one cm incision is made in the gingivobuccal sulcus just beneath the zygomatic buttress and a Freer elevator is inserted to dissect the soft tissues in a supraperiosteal plane ii. a heavier instrument is then inserted and by applying superior, lateral, and anterior force the bone can be reduced c. eyebrow approach - the brow incision is carried down to the frontozygomatic suture and a heavy instrument is placed posterior to the zygoma d. percutaneous approaches - direct route with the more theoretical than practical disadvantage of scarring i. bone hook - the point of the hook is inserted through the soft tissues of the malar area at a point just inferior and posterior to the prominence of the zygoma, so that it engages the infratemporal aspect ii. towel clip iii. bone screw e. intrasinus approach - a gingivobuccal sulcus incision followed by a Caldwell-Luc opening if the anterior sinus wall is intact; an elevator is placed behind the zygoma for reduction I. Approaches 1. supraorbital eyebrow a. palpate the fracture site b. do not shave the eyebrow c. incise down to periosteum in one stroke parallel to the hair shafts d. incise and elevate periosteum 2. lower lid/blepharoplasty incisions - subciliary, lower eyelid, and infraorbital incision a. very similar incisions with the infraorbital incision but associated with a more perceptible scar b. the subcilliary is considered the most difficult, is associated with the highest rate of ectropion, but is felt to be the most cosmetically appealing c. in all three it is important to stair-step the incision so that the periosteal incision is not adjacent to the skin incision as this may create a depression 3. transconjunctival incisions - another approach to the orbital rim and floor which has recently gained more acceptance a. two different methods of this approach: retroseptal and preseptal b. proponents of the retroseptal method claim that leaving an intact lower eyelid reduces the rate of ectropion while preseptal advocates favor avoiding the orbital fat c. both methods are technically demanding and take more time than the blepharoplasty incisions, but leave no external scar d. Appling et.al recently compared transconjunctival with subciliary approaches and demonstrated a significantly lower rate of ectropion and less scleral show, while also advocating the use of lateral cantholysis and canthotomy e. Zingg's study used the transconjunctival approach exclusively and had complication rates under one percent; additionally, he reports no instances in which this approach required a lateral canthotomy for additional exposure 3. other approaches a. extended preauricular incision (figure 22) - mentioned very infrequently in the modern literature as it puts the frontal branch of the facial nerve at risk b. coronal incision - indicated in zygomatic fractures associated with frontal sinus or nasoethmoid fractures J. Fixation a. although controversy exists, a great many surgeons feel that, in most cases, displacement of a zygomatic fracture necessitates internal fixation after reduction i. postoperative displacement can be associated with significant functional and aesthetic sequelae, such as malar flattening, ocular dystopia, enophthalmus, and persistent dysesthesia of the infraorbital nerve. ii. two studies examining large numbers of zygomatic fractures over a recent ten year period reported treating approximately 80% of displaced zygomatic complex fractures with open reduction and internal fixation (Zingg et.al., and Covington et.al.) while the older literature reports about 50% b. miniplates vs wire osteosynthesis i. there is a definite trend towards almost universal use of miniplates over wires ii. the advantage of the plate fixation is the three- dimensional stability it affords by virtue of its width iii. the disadvantage of the plate is the significant expense and the increased technical support required c. fixation sites i. another controversial area, with some studies demonstrating excellent postoperative results after plating only the frontozygomatic suture and others advocating the principle of three point fixation ii. Davidson's recent study looked at 25 combinations of plate and wire fixation in zygomatic complex fractures created in human skulls; and determined that the use of at least one plate, and the incorporation of the frontozygomatic suture line as one of the sites of fixation will achieve stable fixation 1. they chose one millimeter as the upper limit of acceptable displacement when a force equivalent to that of the masseter was applied 2. figure 17 explains the amount of displacement that was measured in each of the 25 combinations of fixation 3. because the displacement was measured at some distance from the zygoma, five millimeters on the chart is equivalent to one millimeter of actual displacement iii. Tarabichi's recent study demonstrated transsinus reduction with miniplating of the lateral buttress in seventeen patients with isolated zygomatic fractures, and found that the one patient with poor post-operative results had a comminuted orbital rim iv. in one of the largest series, Zingg et.al. classified zygomatic fractures into three categories with category one including items A, B, and C; category two pictured by D is the zygomatic complex fracture; and the third category is the multifragmented zygomatic complex fracture 1. closed reduction was applied to virtually all fractures in the first category 2. closed reduction was also applied to all of the second category's fracture except those with prolapse of the orbital contents; and if the reduction held against "digital pressure" the procedure was terminated 3. upon failure of the reduction with such pressures open reduction and internal fixation (ORIF)was carried out using only one plate and the frontozygomatic suture line in the majority of cases 4. fractures in the third category were all fixed with ORIF using brow, gingivobuccal, and transconjunctival approaches, and miniplating was applied to the frontozygomatic suture, zygomaticomaxillary buttress, and the malar prominence in most cases 5. a great emphasis was placed on exploring the orbital floor in all of the category three fractures to ensure reduction at the interface of the zygoma and sphenoid; because they felt that this was the most common area of nonunion, often accounting for a bad outcome 6. interestingly they also placed great emphasis on avoiding miniplates on the zygomatic arch, the infraorbital rim, the orbital floor, and the anterior maxillary wall because of the resulting problems with inaccurate restoration, inflammatory reactions, and bone resorption 7. instead of plates in these areas, vicryl or wires were used, and meticulous reconstruction of these often comminuted areas was carried out 8. Zingg's results in this series were excellent with only 3.6% having post-operative asymmetry, and 3.9% having enophthalmus with diplopia K. Summary 1. determine the presence of comminution 2. non-comminuted zygomatic complex fractures and zygomatic arch fracture a. attempt closed reduction b. if open reduction is indicated - miniplate at least one site and incorporate the frontozygomatic suture line 3. comminuted zygomatic complex fractures a. open reduction and internal fixation b. plate the frontozygomatic suture and the zygomaticomaxillary suture lines 4. the transconjunctival approach is superior for those with experience --------------------------------------------------------------------------- BIBLIOGRAPHY Macias JD, Haller J, Frodel JL Jr. Comparative postoperative infection rates in midfacial trauma using intermaxillary fixation, wire fixation, and rigid internal fixation implants. Arch Otolaryngol Head Neck Surg 1993; 119(3):308 Laine FJ, Conway WF, Laskin DM. 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