You are in: eMedicine Specialties > Otolaryngology and Facial Plastic Surgery > TRAUMA Frontal Sinus FracturesArticle Last Updated: Apr 30, 2007AUTHOR AND EDITOR INFORMATIONAuthor: E Bradley Strong, MD, Assistant Professor, Department of Otolaryngology-Head and Neck Surgery, University of California at Davis E Bradley Strong is a member of the following medical societies: Alpha Omega Alpha and American Rhinologic Society Editors: Hassan H Ramadan, MD, MSc, Professor and Vice-Chair, Department of Otolaryngology-Head and Neck Surgery, Professor, Department of Pediatrics, West Virginia University; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine; Stephen G Batuello, MD, Consulting Staff, Colorado ENT Specialists; Christopher L Slack, MD, Otolaryngology-Facial Plastic Surgery, Private Practice, Associated Coastal ENT; Medical Director, Treasure Coast Sleep Disorders; Arlen D Meyers, MD, MBA, Professor, Department of Otolaryngology-Head and Neck Surgery, University of Colorado School of Medicine Author and Editor Disclosure Synonyms and related keywords: frontal sinus fractures, FS, FS fractures, nasoorbitoethmoid fractures, NOE fractures, frontal sinus trauma, FS trauma, facial bone fracture, broken bone, face, fractured face, sinus, facial trauma, facial fractures INTRODUCTIONThe frontal sinus (FS) is extremely resilient to injury. However, high-velocity impacts, such as motor vehicle accidents and assaults, can result in FS fractures. The potential for intracranial injuries, aesthetic deformities, and late mucocele formation is high. The treatment goals of FS fractures are an accurate diagnosis, avoidance of short- and long-term complications, return of normal sinus function, and reestablishment of the premorbid facial contour. The treating physician must have a concise algorithm for diagnosis and treatment of these injuries. FrequencyFS fractures account for 5-12% of all facial fractures. EtiologyMotor vehicle accidents account for 71% of FS fractures, assaults 10%, industrial accidents 5%, recreational accidents 4%, and other causes (eg, gunshot) 6%. PathophysiologyIsolated anterior table fractures account for 33% of FS fractures. Combined fractures of the anterior table, posterior table, and/or nasofrontal recess (NFR) appear in 67% of cases. Isolated posterior table injuries are rare. As many as 33% of patients have an associated CSF leak. ClinicalPatients with FS fractures often have associated facial injuries or panfacial fractures. A thorough head and neck examination is imperative.
RELEVANT ANATOMYDevelopment The FS is absent at birth. The anterior ethmoid cells invade the frontal bone at 2 years of age, and the FS attains adult size at approximately 15 years of age (see Image 1) The FS measures 30 mm tall, 25 mm wide, and 19 mm deep in the average adult (see Image 2). Average FS volume is 10 cm3. The FS is most commonly bilateral, asymmetric, and pyramidal in shape.
Anterior table The anterior table forms part of the forehead, brow, and glabella. It averages 4 mm in thickness but can be as thick as 12 mm. The anterior table is more resistant to fracture than any other facial bone. Posterior table The posterior table abuts the anterior cranial fossa. Thickness of the posterior table ranges from 0.1-4.8 mm, and it is much less resistant to injury than the anterior table. Frontal sinus ostia The FS has 2 ostia located on the posterior inferior aspect of the sinus floor. They are positioned anterior to the anterior ethmoid air cells, medial to the orbit, lateral to the intersinus septum, and posterior to the frontal bone. Each ostium is approximately 3-4 mm in diameter and represents the sole drainage site for the FS. The true ostium is the narrowest point of an hourglass configuration. The FS infundibulum is located cephalad to the ostia (the upper part of the hourglass) and narrows down to the true ostia. The NFR widens out below the ostia (the lower part of the hourglass) and enters into the ethmoid infundibulum. The NFR is extremely short in 85% of individuals and, thus, is more accurately described as a recess rather than a true duct. Neurovascular supply The supraorbital and supratrochlear vessels provide arterial supply to the FS. Venous drainage occurs through 3 pathways: the facial vein, the ophthalmic vein/cavernous sinus, and the foramina of Breschet/subarachnoid space. Sensory innervation of the FS comes from the ophthalmic branch of the trigeminal nerve. WORKUPLab Studies
Imaging Studies
TREATMENTMedical therapyThe most appropriate treatment of FS fractures can be complex and, at times, controversial. The treating physician should have a clear algorithm in mind for management of different fracture patterns. The author proposes a conservative algorithm for the treatment of most FS injuries (see Image 3). Treatment options include observation, open reduction and internal fixation (ORIF), sinus obliteration, sinus exenteration (ie, removal of anterior table, Reidel procedure), and sinus cranialization. The algorithm is based on 5 anatomic parameters that need to be evaluated before deciding on the most appropriate treatment option. These parameters include NFR fractures, anterior table fractures, posterior table fractures, dural tears (CSF leak), and degree of fracture comminution. Nondisplaced or minimally displaced ( <1-2 mm) isolated anterior table fractures can be managed conservatively with local wound care and analgesics. Patients should be closely observed for signs of frontal sinusitis, which may indicate fracture involvement in the nasofrontal duct. Surgical therapyGeneral goals of surgical therapy include protection of intracranial contents, prevention of early and late complications (eg, meningitis, mucocele), restoration of aesthetic forehead contour, and return of normal FS function. Although accomplishing all these goals may not be possible, the intracranial contents must be protected, and a "safe" sinus must be reconstructed. Repair of aesthetic and functional deformities can be addressed secondarily. NFR fractures Nondisplaced fractures involving the floor of the FS or anterior ethmoid region should raise suspicion for NFR injury (see Image 3). In the absence of associated FS injuries, close observation and repeat CT at 4-6 weeks may reveal sinus opacification, indicating outflow obstruction. If NFR injury is highly suspected, but it cannot be confirmed on the CT scan, a frontal sinusotomy and endoscopic evaluation is indicated (see Intraoperative Details). Displaced fractures usually require FS obliteration. Some authors have advocated more conservative approaches, such as NFR reconstruction with mucoperiosteal flaps (eg, Sewell-Boyden flaps) or intersinus septectomy, which theoretically allows the injured sinus cavity to drain into the uninjured NFR. These techniques have not gained significant popularity. Anterior table fractures Nondisplaced fractures can generally be managed nonoperatively. Nondisplaced anterior table fractures rarely result in mucocele formation, functional deficit, or aesthetic deformity (see Image 3). Advise patients of a small risk of external deformity, which can often be repaired endoscopically. Displaced fractures greater than 1-2 mm have an increased risk of aesthetic deformity and mucocele formation. ORIF of the fracture is indicated within 7-10 days.
Posterior table fractures Treatment of posterior table fractures remains controversial (see Image 3). A review of the literature reveals that some authors advocate exploration of all posterior table fractures, no matter how slight. Others recommend observation even when the posterior table is significantly displaced. No prospective randomized studies are reported to corroborate the different approaches. Nondisplaced fractures have a reduced risk of complications (eg, dural tears, CSF leak, meningitis, mucocele formation) when compared to displaced posterior table fractures. The need for exploration often depends on the presence or absence of a CSF leak.
Displaced fractures have an increased risk of complications and require a more aggressive approach.
Preoperative detailsAll patients undergoing open FS procedures should be counseled regarding potential risks, including the following:
Intraoperative detailsFrontal sinusotomy and endoscopy Make a 1- to 1.5-cm skin incision placed midway between the medial canthus and the glabella, approximately 1 cm inferior to the brow. The incision is well hidden when placed inferior and deep to the curve of the brow.
A guarded needle-point monopolar electrocautery is used to incise the periosteum. Use a cutting burr to open a 4- to 5-mm frontal sinusotomy approximately 1 cm medial and inferior to the medial brow. Incise FS mucosa; instill oxymetazoline for decongestion, if necessary. Direct visualization of the NFR is obtained with a nasal endoscope to document any mucosal laceration or CSF leak.
Avoid NFR instrumentation because it may result in NFR stenosis. The procedure can be repeated on the contralateral side if necessary. The FS trephine procedure is limited by FS anatomy. Lateral fractures and intersinus septations may limit visualization. Position patient 180° away from anesthesia. Explore all forehead lacerations. Although lacerations alone are usually inadequate for exposure, diagnosis, and repair of FS fractures, they should be used to assist with fracture repair. For coronal flap dissection, part the hair in a widow's peak pattern 4-6 cm behind the anterior hairline. A 1- to 2-cm strip of hair can be shaved along the incision line, but this is not necessary. The scalp is incised and elevated in a subgaleal plane. Avoid brow incisions to prevent prominent scars and forehead anesthesia. Lateral flap dissection is performed between the temporoparietal fascia (superficial temporal fascia) and the temporalis muscle fascia (deep temporal fascia) (see Image 4). The temporoparietal fascia and frontal branch of the facial nerve are elevated with the flap. The temporalis muscle fascia can also be incised and elevated with the flap to provide an extra layer of protection for the facial nerve. Identify and protect the supraorbital and supratrochlear neurovascular pedicles. The pericranium is incised 1-2 cm above the sinus and elevated below the fracture. If any concern about a posterior table injury or dural tear exists, elevate the entire pericranial flap from the coronal incision line. The vascularized pericranial flap may then be used for a dural repair. Reduce the concave fracture segments. If the fracture segments overlap, a bone hook can be insinuated between the fragments and pulled forward.
Preoperatively, obtain an anterior-posterior plain radiograph (ie, Caldwell projection) of the skull. Alternatively, a surgical navigation system can be used intraoperatively to localize the sinus. Prepare the patient for a coronal flap and abdominal fat graft. Confirm the orientation of the Caldwell radiograph by comparison with a CT scan. Cut out a FS template from the Caldwell radiograph. Lateral "wings" paralleling the orbital rims should be left in place (see Image 8). To assist with accurate intraoperative placement of the template, an "R" should be scratched into the right side of the template. Perform a coronal incision and elevate a scalp flap (see ORIF). If the anterior table of the FS is not comminuted, the FS template is applied over the pericranium. Tattoo an outline of the FS on the bone with an 18-gauge needle and methylene blue. Incise the pericranium in the coronal plane. Make parallel lateral cuts along the temporal line and raise a large inferiorly based pericranial flap. Take care to maintain a wide pedicle and avoid perforation of the flap. The midline elevation should continue to approximately 1 cm below the outline of the FS. A drill can be used to perforate the outline of the flap. Angle the drill toward the sinus cavity to avoid intracranial penetration and injury. The perforations can then be joined with an oscillating saw. A high-speed Midas Rex drill with a B-1 bit is efficient and obviates the need for an oscillating saw. A 4-mm osteotome is used to fracture the superior orbital rims and glabella at the periphery of the sinus. Avoid injuring the supraorbital/supratrochlear neurovascular pedicles. A curved osteotome is then placed through the saw kerf, and the intersinus septum is fractured. Repeat this step around the periphery of the sinus with multiple osteotomes until the anterior table of the sinus is hinged open inferiorly. The use of several osteotomes allows the surgeon to repeatedly place a new osteotome without losing the purchase from the previous one. Assess the posterior table comminution and make a decision regarding sinus obliteration or cranialization. If the sinus is to be obliterated, meticulously debride all mucosa from the sinus with cutting and diamond burrs. Loop magnification can assist with the debridement. Pay particular attention to the periphery of the sinus and the NFR. Treat free bone fragments in a similar fashion. The FS infundibulum mucosa is elevated inferiorly, and a temporalis muscle plug is placed to occlude each ostia. Small sinus cavities can be obliterated with the pericranial flap. A small amount of bone is first removed from the inferior portion of the bone flap. The vascularized pericranial flap is then passed through the bony defect into the sinus cavity. Spontaneous osteoneogenesis and auto-obliteration have also been advocated.
FS cranialization The surgical approach for cranialization is identical to that described for FS obliteration. Exposure of the sinus rarely requires osteotomies because of the severity of the anterior table injury. Remove posterior table bone by using elevators and rongeurs. Large pieces of posterior table bone should be divested of mucosa and preserved for reconstruction of the anterior table during closure. Cleanse grossly contaminated bone fragments and soak the fragments in Betadine until needed for reconstruction. The posterior sinus margin is then drilled flush with the anterior cranial fossa. Each FS infundibulum is drilled out, the mucosa is inverted, and the ostium is occluded with a temporalis muscle plug. Simple lacerations of the dura can be repaired with interrupted 5-0 nylon sutures. More complex injuries may require neurosurgical debridement and dural closure with a pericranial flap. A small bony defect must be fashioned in the anterior table to allow the pericranial flap to pass intracranially without cutting off the blood supply. Cleanse the preserved bone fragments with saline and reconstruct the anterior table using 1- to 1.2-mm microplates. Outer table calvarial bone grafts should be used as necessary to supplement native bone. Close the scalp in layers. Place drains and a pressure dressing as described above. Postoperative detailsPenrose drains are removed after 24 hours. Pressure dressing is discontinued after 3 days. Skin sutures and staples are removed after 10-14 days. Follow-upThe need for long-term follow-up of patients with FS fractures cannot be overemphasized. The risk of late mucocele formation is significant. Perform repeat CT or MRI if the patient has symptoms of recurrent infection. Trephination may be necessary in rare cases because radiographic identification of an infected fat graft is difficult. COMPLICATIONSImproper management of FS and NFR injuries can result in significant complications, including aesthetic deformity, forehead paresthesia or anesthesia, chronic sinusitis, mucopyocele, diplopia, visual loss, meningitis, brain abscess, and death. Management of postoperative mucoceles usually involves a revision obliteration procedure or sinus exenteration (ie, Reidel procedure) with subsequent cranioplasty. OUTCOME AND PROGNOSISPatients with mildly displaced anterior table fractures do extremely well after surgical repair, and significant long-term sequelae are uncommon. Displaced FS fractures generally result from more extreme forces. Consequently, most patients who undergo surgical treatment of these injuries have some long-term sequelae. The most common sequelae are mild and include frontal headache (20%), sinus infections (12%), sinus fullness (11%), sinus drainage (10%), and forehead depression (10%). Less common but more severe long-term sequelae include diplopia (4%), seizures (4%), mucocele formation (exact incidence uncertain [0-10%]), and brain abscess (1%). For excellent patient education resources, see eMedicine's Headache Center and Breaks, Fractures, and Dislocations Center. Also, visit eMedicine's patient education articles, Sinus Infection and Facial Fracture. FUTURE AND CONTROVERSIESThe most common controversies associated with FS trauma are the aggressiveness of surgical repair for a given fracture type and the optimum material used for FS obliteration. Unfortunately, long-term follow-up in patients with FS fractures is extremely difficult. Definitive studies on the most efficacious management do not exist. The author has proposed a conservative treatment algorithm (see Image 3) to guide the surgical repair of given fracture types. When obliteration is indicated, the author prefers autologous fat. Other materials that have been used include muscle, bone, fascia, osteoneogenesis (auto-obliteration), hydroxyapatite cement, and bioactive glass. Although autologous fat does have donor site morbidity, it is readily available, easy to handle, and cost-effective. Most importantly, it has long-term proven efficacy. MULTIMEDIA
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Frontal Sinus Fractures excerpt Article Last Updated: Apr 30, 2007 | ||||||||||||||||||||||||||||||||||||||||||