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MICROPLATING OF FRONTAL SINUS FRACTURES GLENN GREEN, MD, ROBERT H. MATHOG, MD

The repair of frontal sinus fractures is focused on the prevention of immediate and long-term adverse sequelae. Early diagnosis and treatment planning are essential. Depending on the site(s) and extent of injury, treatment usually consists of reconstruction with or without obliteration of the sinuses. The microplate is a new valuable tool that is useful in the treatment of isolated anterior frontal sinus fractures, comminuted anterior wall frontal sinus fractures, and anterior frontal sinus wall fractures associated with other sinus wall injuries.

Over the past 100 years, surgeons have treated frontal sinus fractures using various regimens. The results have shown the importance of early recognition and treatment of frontal sinus fractures to prevent immediate and long-term complications. 1"3 More recently, materials research has lead to the development of strong nonreactive microplates that can be placed inconspicuously between the surface of bone and the overlying soft tissue. 4 These plates are a powerful tool in the armamentarium of the otolaryngologist, enabling more secure and rapid treatment of frontal sinus fractures in comparison to alternative techniques. 5

INDICATIONS Microplates are especially useful in treating isolated anterior wall frontal sinus fractures and in reconstructing comminuted anterior wall frontal sinus fractures associated with posterior or inferior wall injuries (Fig 1). Such plates are barely noticeable and are effective in stabilizing bone fragments in anatomic position. To make the diagnosis and determine the fracture status there should be a physical examination with particular attention to deformities of the forehead and orbital rims, ocular mobility, position and function of the eyes, and cerebrospinal fluid leaks. For imaging studies we prefer computed tomography (CT) scans in axial and coronal planes (Fig 2). 6 Fractures with the potential to cause forehead or orbital rim deformity must be reduced, and if the bones are unstable they should be repaired with microplates. Operative exploration during fracture repair has the additional benefit of allowing direct evaluation of the extent of the injury. Some authors advocate exploration of all frontal sinus fractures for reliable evaluation 7; however, an isolated anterior fracture of the frontal sinus without deformity can often be treated with conservative medical management. 8-1° From the Department of Otolaryngology--Head and Neck Surgery, Wayne State University School of Medicine, Detroit, MI. Address reprint requests to Glenn Green, MD, Department of Otolaryngology-Head and Neck Surgery, Wayne State University, School of Medicine, 540 E. Canfield, 5E-UHC, Detroit, MI 48201. Copyright @1995 by W B Saunders Company 1043-1810/95/0602-0002505.00/0

In contrast to anterior wall fractures, posterior wall fractures of the frontal sinus are more often associated with central nervous system injury. 11 The diagnosis and extent of injury should be evaluated jointly by the surgeon and other members of the neurosurgical department. Although rarely observed, an isolated posterior fracture, if limited and nondisplaced, can be managed conservatively. 8'12 Nondisplaced fractures usually do not need to be explored unless there is evidence of nasofrontal duct involvement, open fracture or cerebrospinal fluid leak.13 If displacement of the posterior wall is observed, then exploration through an external osteoplastic flap approach should be considered. For the more significant comminuted fractures that are associated with obvious dural tears, cerebrospinal fluid leaks or p n e u m o c e p h a l u s , a formal c r a n i o t o m y m a y be required. 14 Although posterior wall fractures of the frontal sinus can be isolated to the posterior wall and skull base, they usually occur as through-and-through fractures associated with contamination and comminution of bone. In this type of injury, soft tissue and bone may be nonviable, and a significant defect can result after debridement. Under these conditions, a reasonable option is to fill the sinus with a vascularized obliteration. 15 The surgeon can also reconstruct the anterior wall of the frontal sinus and obliterate or cranialize the sinus with the anterior displacement of the brain. 16 It is rarely recommended for the surgeon to remove the anterior and posterior walls of the frontal sinus and collapse the forehead tissues onto the anterior fossa. The collapse of the forehead (often called a Reidel procedure) causes a severe deformity that is difficult to correct at a later time. A flap with its own blood supply is preferred. Filling the defect with a temporalis muscle galea flap provides such tissue, but it can also cause problems such as depression of the temple region and/or alopecia over the donor area. Free grafts (ie, fat or muscle) probably should be avoided as these grafts require a well-vascularized bed, and, if this is not available, there is the potential for infection and further loss of tissue.

CONTRAINDICATIONS Surgery including frontal bone plating is contraindicated in patients who are neurologically unstable and in w h o m there is a question of the extent of injury. Moreover, the

OPERATIVE TECHNIQUES IN OTOLARYNGOLOGY--HEAD AND NECK SURGERY, VOL 6, NO 2 (JUN), 1995: PP 111-117

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precedence over the sinus fracture, l~ In such cases, initial management consists of airway management and resuscitation along with careful neurological evaluation. Early repair is contraindicated in the face of obvious poor prognosis for survival, severe associated medical conditions, severe associated injuries, or elevated intracranial pressure. 17 For extensively contaminated forehead lacerations, it may be prudent to initially clean and debride the w o u n d of devitalized tissue, with subsequent repair of the frontal bone performed approximately 3 days later. In general, gunshot wounds and forehead lacerations do not contraindicate repair of the frontal sinus18; however, examination should be closely performed for associated injuries. Most patients with severe and even comminuted frontal sinus fractures can undergo immediate reconstruction.

PATIENT PREPARATION Patients should be started on antibiotic prophylaxis. If there are no known drug allergies, we prefer ampicillin or cefazolin, or a third-generation cephalosporin if the posterior wall is also affected. 19 These antibiotics should continue to be administered intraoperatively and postoperatively. The physical examination should be followed quickly by CT scan studies and appropriate consultation with other services--ie, neurosurgery and/or ophthalmology. Ideally, repair should occur as soon as possible to decrease the risk of infection. FIGURE 1. Types of frontal sinus fractures that are effectively treated with microplate fixation: (A) isolated anterior wall, (B) coraminuted anterior wall, (C) anterior posterior wall frontal sinus fractures.

definitive treatment should be delayed if there is a significant risk of infection of the area. Frontal sinus fractures that occur secondarily to high impact are often associated with other injuries that take

OPERATIVE TECHNIQUES SURGICAL EXPOSURE Our repair of frontal sinus fractures is accomplished through one of several approaches for obtaining exposure of the frontal sinus: lacerations occurring with the initial

FIGURE 2. CT scan m (A) axial and (B) coronal planes showing anterior wall frontal sinus fractures. 112

MICROPLATING FRONTAL SINUS FRACTURES

injury, and frontoethmoid, sub-brow and bicoronal incisions (Fig 3). Lacerations of the forehead can be used, but if they are limited, they should be extended into a crease or furrow line for appropriate exposure. In general, if extension of the laceration crosses a crease or furrow line then another incision should be considered. The area of injury and the estimated exposure necessary for the repair will determine the site and the length of the incision. In the frontoethmoid incision for anterior wall fractures (Fig 4) a surgeon makes a curvilinear incision along the frontal process of the maxilla and upward below the medial part of the eyebrow. Usually, the incision is placed one-half of the distance from the inner caruncle to the d o r s u m of the nose. The incision is t h e n carried through the soft tissues, ligating or cauterizing the angular vessels. The periosteum of the frontal process is incised and elevated superiorly to expose the area of depression. For the sub-brow approach the frontoethmoid incision is extended laterally beneath the brow and medially across the nasoglabellar crease to become continuous with a similar incision of the opposite side (Fig 5). Again, the angular vessels are identified and cauterized. Elevation is performed in a plane beneath the hair follicles, above the orbicularis oculi muscle, and across the prominence of the brow. The supraorbital and supratrochlear vessels and nerves are usually identified, and although they are kept deep to the dissection, neurovascular branches to the forehead may have to be sacrificed. The dissection then enters a plane between the galea and periosteum, and at this point, the surgeon has the option of directly exposing the fracture or continuing more superiorly until the dissection is above the area of damage. The periosteum then can be elevated retrograde to expose the fragments, but the surgeon should attempt to preserve as much as possible the vascularized periosteal attachments. The mucoperiosteum that lies on the deeper portion of the fracture should also be kept intact. Another choice, not generally used in males with evidence of a receding hairline, places the incision parallel to the coronal suture (Fig 6). It is made at least 2 to 3 centimeters behind the hairline in a gentle curve that is extended to a point several centimeters above the pretragal creases. The area for incision is prepared by limited

shaving, antiseptic solutions, and application of drapes to keep the hair from the wound. Prior infiltration with 1% lidocaine containing epinephrine will help with hemostasis. The knife blade should follow the direction of the hair follicles. The incision is made through the skin, subcutaneous tissues, and galea. Branches of the superficial temporal artery are ligated with fine silk sutures; other bleeding sites are controlled with pinpoint cauterization. The forehead flap is further elevated in a plane between the gales and periosteum. Laterally the dissection is extended deep to the superficial temporalis fascia following the fat plane inferiorly toward the zygomatic arch. In the midline, the elevation proceeds deep to the eyebrows, exposing branches of the supratrochlear and supraorbital vessels that penetrate the periosteum of the bone flap. Lateral extension of skin flaps provides for exposure of a parietal bone and the potential to collect calvarial grafts if they are needed for reconstruction.

CLEANING THE FRACTURE AND DEFINING THE DEFECT After exposure of the frontal sinus fracture is obtained, the fracture site is thoroughly cleaned with suction irrigation. The surgeon should ensure that the w o u n d is clean by washing with saline and mechanical removal of any obvious particles or foreign material. This will help avoid postoperative infection. At this point, the sinus is evaluated for the possibility of the fracture extending to the posterior and/or inferior wall resulting in cerebrospinal fluid leak. Also, examination is performed to evaluate for possible extension of the fracture to the nasofrontal duct. Choice of approach for treating the fracture is made dependent on intraoperative findings. When possible, fragments of the frontal sinus are left connected to their periosteum and elevated into position with skin hooks and small elevators. Otherwise, frontal sinus fragments are removed for reconstruction in vitro of the frontal sinus. Before reconstruction, the surgeon should ensure that the sinus is completely obliterated or at least has the potential to function normally. The patient should be free of cerebrospinal fluid leaks or major defects of the anterior fossa. Care should also be taken during the preparation of the recipient site to avoid injury to the sagittal sinus and/or underlying dura.

PLATE CHARACTERISTICS

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Low-profile plates (Leibinger L.P., Dallas, TX) of a 0.55-mm thickness using 1.2- to 1.7-ram self-tapping screws (or a similar plating system) are used for the reconstruction. 2° These titanium plates are corrosionresistant and biocompatible. There is also minimal scatter with postoperative CT scans and magnetic resonance imaging (MRI). 21'22

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PLATING Isolated anterior table fractures can sometimes be repaired with a single plate (Fig 7). However, most fractures are too c o m m i n u t e d and will require multiple plates. Wire fixation should probably be avoided because fragments tend to sway and there is insufficient rigidity to hold the anatomic position. 113

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~(J.}'/)~ FIGURE 5. Repair of frontal sinus fracture through a sub-brow incision: (A) comminuted anterior wall fracture, (B) location of incision, (C) reduction of fracture. After exposure of the fracture, the plate is bent to an appropriate contour and adjusted to span the defect with preferably two screws placed in solid bone adjacent to the fragments. The plate should also be applied to thicker areas of bone. The plate should be bent to fit closely to the forehead so that it is not palpated or seen following fixation. With the plate held against the fragments, hole positions are marked with solution or scored. Alternatively, the plate can be held in position as the surgeon drills through the holes and bone. The holes should be confined to the outer cortex and diploe, using a K wire or an appropriate-size drill. The screws should be just long enough to pass through the outer cortex and the diploe and engage the inner cortex, but in cases in which bone is thin, the screws will often penetrate the inner cortex. The surgeon has the option of applying the screws first to the fragment and then to the adjoining bone or in reverse order. If there are many fragments, multiple plates will be needed to achieve a satisfactory fixation, but only the minimum number of plates necessary should be used to hold the bones in position.

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FIGURE 6. Repair of a frontal sinus fracture through a bicoronal incision: (A) location of incision, (B) elevation of periosteum, (C) management of temporal dissection with preservation of facial nerve. The temporal dissection takes place in a plane deep to the superficial layer of temporalis fascia.

IN VITRO APPROACH WITHOUT OBLITERATION The in vitro approach (Fig 8), especially when there is comminution, allows accurate repositioning of fragments to each other and to the nontraumatized portion of frontal bone. Moreover, the repair in vitro of the frontal sinus fracture can greatly reduce operative time. Using this technique the anterior frontal sinus wall is reconstructed away from the surgical field. Meanwhile, a separate surgical team can repair associated injuries (ie, injury to the nasofrontal duct) or cranialize or obliterate the frontal sinus. On a separate table, bone fragments are assembled into a one-piece unit. As individual pieces are joined together, low profile plates are held against the fragments. The holes are then drilled with a K wire or an appropriMICROPLATING FRONTAL SINUS FRACTURES

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E FIGURE 7. Repair of isolated anterior wall fracture with single plate: (A) fracture location, (B) sub-brow incision, (C) position of plate, (D) position of screws.

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FIGURE 9. Bone grafting of frontal bone defect: (A) bicoronal incision, (B) frontal fracture and defect of anterior wall, (C) exposure of parietal bone, (D) in vitro application of microplates to fragments and graft, (E) fixation of reconstructed wall to frontal bone.

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C FIGURE 8. In vitro repair of anterior sinus wall fracture: (A) comminuted anterior wall fracture, (B) plate fixation of fragments (usually on a separate table), (C) application of plated-anterior wall unit to frontal bone. ate-size drill bit. The screws should be just long enough to pass through the outer cortex and diploe and engage or just pass through the inner cortex. Multiple plates will often be needed to achieve a satisfactory fixation, but only the minimum number of plates necessary should be used to hold the bones in position. If bone loss is excessive the reconstruction can be supplemented with bone grafting. Usually, an outer cortex graft is collected from the parietal region and contoured to fit the missing area of bone loss (Fig 9). When using this technique, the scalp posterior to the coronal incision is elevated and the periosteum is elevated off of the parietal bone. The bone gap, to be replaced by a bone graft, is measured by cutting a 4 x 4 sponge to the size of GREEN AND MATHOG

the defect. Marking solution is then used to demarcate a similarly-sized (but slightly larger) area of the donor site. The graft is collected by first forming an island of bone with cutting burrs. A trough is created by removal of additional bone around the donor site. The outer cortical bone graft is removed using an osteotome. Bone wax is applied to the inner table and diploe of the parietal bone to control bleeding. Microplates are then used to anchor the graft to the other fragments. Once completed, the reconstructed wall is returned to the primary surgical field and holes are placed to anchor the unit to the skull. After the holes are drilled, the anterior frontal sinus wall position is checked and screws are placed so as to engage the inner cortex. It is important to use microplates with sufficient rigidity to maintain forehead contour but yet with sufficient malleability to allow some additional b e n d i n g to reseat the reconstructed unit. Elevated areas of bone can be contoured with cutting burrs. Small gaps after reconstruction can be filled with bone pat&

OSTEOPLASTIC APPROACH WITH OBLITERATION The osteoplastic flap is used primarily for exploration of the sinus (Fig 10). The exposure allows the surgeon to look for a cerebrospinal fluid leak and involvement of the nasofrontal duct. When these complications occur obliteration is indicated. 8'1° When there is a fracture of the anterior frontal sinus 115

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FIGURE 10. Osteoplastic flap approach with fat obliteration of the sinus: (A) fracture of anterior and posterior wall of frontal sinus, (B) bicoronal exposure and plating of anterior wall, (C) x-ray template used for periosteal incision; (D) sagittal osteotomy and elevation of anterior wall with curved osteotome, (E) removal of mucosa, (F) reduction of posterior wall fragments, (G) collection of abdominal fat, (H) plate fixation and obliteration of sinus with fat. and associated injury to the posterior and/or inferior wall, the anterior wall of the frontal sinus should be first reduced and fixed with microplates. Subsequently the outline of the frontal sinus is designed with a "six foot" Caldwell x-ray template. The anterior wall is then obliquely osteotomized with an oscillating saw. Final cuts are made with a curved osteotome at the orbital rims and between the anterior wall and sinus septum. The sinus is opened by elevating the bone flap. Through this exposure, dura can be repaired and bone fragments returned to normal position. The mucosa of the sinus should then be r e m o v e d with a periosteal elevator. A microscope or loupe is often used to inspect the bone, and any areas suspected of containing mucosa should be cleaned with a cutting mastoid burr. The sinus cavity is then filled with abdominal fat. The bone flap is replaced and secured with the chromic sutures through the periosteum or with additional microplates.

CLOSURE Penrose or suction drains are placed between the periosteum and galea. Subcutaneous and subcuticular layers of skin are then closed with chromic sutures. The skin is closed with running or interrupted 5.0 nylon sutures. Incisions are covered with antibiotic gauze. A light compression dressing of fluffs and a stretch gauze are applied. Postoperative prophylactic antibiotics are administered for 5 to 7 days. The dressings should be changed in 24 hours and the w o u n d inspected at that time. Another dressing should be applied for at least 72 hours. Sutures are removed in 5 to 7 days.

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COMPLICATIONS Complications related to frontal sinus fractures arise from direct injury, failure of diagnosis, and as a consequence of normal or aberrant healing. If the plate is palpable or seen following fixation, the plate may have to be removed. 23 This is performed through the same incision. Other complications include heat or cold intolerance and loosening of screws, under which circumstances the plate may need to be removed. 23 Lacerations of the forehead are often associated with soft tissue damage and embedded foreign material, predisposing the repair to subsequent infection. To avoid this problem, wounds should be thoroughly cleaned and debrided and prophylactic antibiotics administered for 5 to 7 days. If an infection develops, the physician should obtain cultures and check for appropriateness of antibiotics. Removal of the plate, further debridement and drainage may be necessary. 23 Any unsightly scars that develop later can be corrected with appropriate scar revision surgery. The sub-brow and bicoronal approaches unfortunately can damage branches of the supraorbital nerves and vessels that enter the forehead tissues. Loss of sensation is variable, and although return of function can be expected, the patient should be warned about the possibility of anesthesia or paresthesia of the region. 24 Depression of the frontal bone can result from inadequate reduction and fixation and/or from absorption of bone. This can be treated in the early postoperative period by another reduction and fixation. Later, when the bone is healed, the defect can be repaired with onlay grafts from nearby parietal bone. 25 Sinusitis and/or mucocele formation can occur especially if there has been injury to the frontonasal duct. These complications may

MICROPLATING FRONTAL SINUS FRACTURES

b e s e e n w i t h i n m o n t h s , b u t a d e l a y e d a p p e a r a n c e 10 to 20 y e a r s l a t e r is n o t u n c o m m o n . 8'1° E x t e n s i o n of t h e m u cocele into the orbit can cause ocular complication whereas erosion into the anterior fossa may result in meningitis, epidural and/or subdural abscess, cerebritis, and/or brain abscess, s

CONCLUSION Frontal sinus fractures may occur as isolated or complex c r a n i o f a c i a l i n j u r i e s . E a r l y d i a g n o s i s a n d t r e a t m e n t is mandatory. D i s p l a c e d f r a c t u r e s of t h e a n t e r i o r w a l l w i l l require reduction and probable microplating either using i n v i v o o r in v i t r o t e c h n i q u e s . Fractures involving the posterior and/or inferior walls require osteoplastic flap e x p l o r a t i o n a n d p o s s i b l y o b l i t e r a t i o n w i t h fat a n d / o r cranialization procedure. Associated anterior wall fractures may also be managed with microplate fixation. P a t i e n t s m u s t b e f o l l o w e d c l o s e l y f o r e a r l y o r late u n c l e sizable s e q u e l a e .

REFERENCES 1. Teachenor FR: Intracranial complications of fracture of the skull

mvolvmg the frontal sinus, lAMA 87:1941, 1926 (abstr) 2. Panas M: Suppurative periostLtis of the wails of the orbit consecutive to suppuration m the frontal sinuses. Ann Surg 7:451-452, 1888 3. Cullom MM: External operation on the frontal sinus. Arch Otolaryngol 11:304-321, 1930 4. Jackson IT, Somers PC, Kjar JG. The use of Champy miniplates for osteosynthesis in craniofacial deformities and trauma. Plast Reconstr Surg 77:729-736, 1986 5. Ewers R, Hare F: Experimental and clinical results of new advances m the treatment of facial trauma. Plast Reconstr Surg 75:25-31, 1985 6. Manson PN, Markowltz B, Mirvis S, et al: Toward CT-based facml fracture treatment. Plast Reconstr Surg 85:202-212, 1990 7. Ioannides C, Freihofer HP, Vrieus J. Fractures of the frontal sinus: A rationale of treatment. Br J Plast Surg 46:208-214, 1993

GREEN AND MATHOG

8. Newman MH, Travis LW: Frontal sinus fractures. Laryngoscope 83:1281-1292, 1973 9. Whited RE' Anterior table frontal sinus fractures. Laryngoscope 89: 1951-1955, 1979 10. Duvall AJ, Porto DP, Lyons D, et al: Frontal sinus fractures: Analysis of treatment results. Arch Otolaryngol Head Neck Surg 113: 933-935, 1987 11. Hybels RL, Weimert TA: Evaluation of frontal sinus fractures. Arch Otolaryngol Head Neck Surg 105:275-276, 1979 12. Rohrich RJ, Hollier LH: Management of frontal sinus fractures: Changing concepts. Clin Plast Surg 19:219-232, 1992 13. Stanley RB, Becket TS: Injuries of the nasofrontal orifices in frontal sinus fractures. Laryngoscope 97:728-731, 1987 14. Sataloff RT, Sanego J, Myers DL, et al: Surgical management of the frontal sinus. Neurosurgery 15:593-596, 1984 15. Mathog RH: Repair of posterior wall fractures of the frontal sinus with a temporalis muscle galea flap, in Mathog RH (ed): Atlas of Cranlofacial Trauma, Phdadelphia, PA, Saunders, 1992, pp 373-376 16. Dufresne CR: The use of immediate grafting m facial fracture management' Indications and clinical considerations. Clin Plast Surg 19:207-217, 1992 17. Derdyn C, Persing JA, Broaddus WC, et al: Craniofaoal trauma: An assessment of risk related to timing of surgery. Plast Reconstr Surg 86.238-245, 1990 18. Key JM, Tami T, Donald PI: Gunshot wound to the frontal sinus. Head Neck 12:357-361, 1990 19. Chole RA, Yee J. Antibiotic prophylaxis for facial fractures: a prospective, randomized climcal trial. Arch Otolaryngol Head Neck Surg 113:1055-1057, 1987 20. Francel PC, Persing JA: Microplating and screw systems for cramal bone fixation. Neurosurg 32:683-685, 1993 21. Fiala TGS, Novelline RA, Yaremchuk MJ: Comparmon of CT unagmg artifacts from craniomaxillofacial internal fixation devices. Plast Reconstr Surg 92:1227-1232, 1993 22. Fiala TGS, Paige KT, Davis TL, et al: Comparison of artifact from craniomaxillofacialmternal fixation devices: Magnehc resonance imaging. Plast Reconstr Surg 93:725-731, 1994 23. Francel TJ, Birely BC, Rmgleman PR, et al: The fate of plates and screws after facial fracture reconstruction. Plast Reconstr Surg 90: 568-573, 1992 24. Luce EA: Frontal sinus fractures: Guidelines to management Plast Reconstr Surg 80:500-508, 1987 25. Maves MD, Matt BH: Calvarial bone grafting of facial defects. Otolaryngol Head Neck Surg 95:464-470, 1986

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