Critical Computed Tomographic Diagnostic Criteria for Frontal Sinus Fractures

J Oral Maxillofac Surg 68:2714-2722, 2010

Critical Computed Tomographic Diagnostic Criteria for Frontal Sinus Fractures Matthew G. Stanwix, MD,* Arthur J. Nam, MD,† Paul N. Manson, MD,‡ Stuart Mirvis, MD,§ and Eduardo D. Rodriguez, MD, DDS储 Purpose: Diagnosis and treatment of frontal sinus fractures (FSFs) have progressed over the previous

30 years. Despite advances in computed tomography, there is no current diagnostic uniformity with regard to classification and treatment. We developed a statistically valid treatment protocol for FSFs based on injury pattern, nasofrontal outflow tract (NFOT) injury, and complication(s). These data outlined predictable injury patterns based on specific computed tomographic findings critical to the diagnosis and ultimate treatment of this potentially fatal injury. Materials and Methods: A retrospective review was conducted on patients with FSF from 1979 to 2005 under institutional review board approval. All computed tomographic scans were reviewed by the authors and fractures categorized by location, displacement, comminution, and degree of NFOT injury. Results: One thousand ninety-seven patients with FSF were identified, 87 expired and 153 had inadequate data, leaving a group of 857 patients. Simultaneous displacement of anterior-posterior tables constituted the largest group (38.4%). NFOT injury occurred in most patients (70.7%) and was strongly associated with anterior (92%) and posterior (88%) table involvement (comminuted 98%). Sixty-seven percent of patients with NFOT injury had obstruction. Five hundred four patients (59.6%) had surgery with 10.4% complications and 353 patients were observed with 3.1% complications. All but 1 patient with complications had NFOT injury (98.5%). Conclusions: Predictable patterns of injury based on specific computed tomographic data play a pivotal role in classification and surgical management of potentially fatal frontal sinus injuries. Radiologic diagnosis of NFOT injury in FSFs, particularly obstruction, plays a decisive role in surgical planning. This is a US government work. There are no restrictions on its use. Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons. J Oral Maxillofac Surg 68:2714-2722, 2010 The development of current ultrafast thin-section multidetector computed tomographic (CT) scanners has improved the conspicuity of facial fractures that may have been missed previously due to wider slice thickness and visible nonisotropic reformations.1-5 Multidetector CT imaging has revolutionized assessment, fracture pattern recognition, and surgical management planning.6 This technology has allowed craniomaxillofacial surgeons to more accurately recognize a specific pattern of injury and precisely relate it to treatment or potential complications. However,

discordance continues to exist between craniomaxillofacial specialists regarding upper facial injuries because there is a paucity of literature regarding preoperative radiographic assessment.7 Frontal sinus fractures (FSFs) comprise 5% to 15% of all craniomaxillofacial fractures, with the majority resulting from high velocity blunt trauma.8-10 Devastating concomitant intracranial injury and associated facial fractures prove the force required to produce these fractures.11-14 Due to the relatively low incidence of these fractures, uniform treatment strategies

*Clinical Fellow, Division of Plastic Surgery, Johns Hopkins School of Medicine, Baltimore, MD. †Clinical Fellow, Division of Plastic Surgery, R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD. ‡Professor and Chief, Division of Plastic Surgery, Johns Hopkins School of Medicine, Baltimore, MD. §Assistant Professor, Department of Diagnostic Radiology, R Adams Cowley Shock Trauma Center, University of Maryland School of Medicine, Baltimore, MD. 储Associate Professor, Division of Plastic Surgery, Johns Hopkins

School of Medicine, Baltimore, MD. Address correspondence and reprint requests to Dr Rodriguez: Plastic and Maxillofacial Surgery, R Adams Cowley Shock Trauma Center, 22 South Greene St, Baltimore, MD 21201; e-mail: [email protected] This is a US government work. There are no restrictions on its use. Published by Elsevier Inc on behalf of the American Association of Oral and Maxillofacial Surgeons 0278-2391/10/6811-0011$36.00/0 doi:10.1016/j.joms.2010.05.019

2714

2715

STANWIX ET AL

based on precise recognition of certain injury features have not been established. Ultimately, treatment decisions depend on various criteria: fracture type, comminution, degree of posterior table fracture, nasofrontal duct injury, neurologic status, and cerebral spinal fluid leak.8,15-17 Management has evolved with technologic advances in radiographic imaging, with greater emphasis on nasofrontal outflow tract (NFOT) injury.8,9,18-22 The proximate relation of the frontal sinuses to the brain requires recognition of any communication that could cause infectious sequels from inadequate frontal sinus drainage. Brain abscesses, subdural empyema, and meningitis are rarely encountered, but morbidity and mortality have been reported due to improper fracture management.23-25 We assessed the severity of FSFs and developed a treatment algorithm based on fracture pattern, degree of NFOT involvement, and complications (Fig 1). The data were derived from a retrospective review of a trauma database, compiled, and discussed in relation to frontal sinus anatomy. This is the first description of radiologic criteria necessary to diagnose the degree of NFOT injury and its relevance to surgical management and complications. Craniomaxillofacial surgeons abreast in evidence-based practice can aid in limiting morbidity from improper frontal sinus management.

Materials and Methods Data from patients with FSFs admitted to the emergency room from 1979 to 2005 were compiled after

institutional review board approval. CT scans were reviewed (by consensus of 2 plastic surgery residents and 1 clinical plastic surgery associate professor and quality assurance from a dedicated trauma radiologist) without knowledge of prior interpretation or management and categorized by location and table involved (Fig 2). Mechanism of injury, demographics, Injury Severity Score, Glasgow Coma Scale, and associated injuries were documented. NFOT injury was defined by at least 1 of the following criteria: frontal sinus floor fracture (Fig 3), fracture of the medial aspect of the anterior table (anterior ethmoid cells; Fig 4), and outflow tract/ductal “obstruction” (Fig 5). Obstruction was defined by a segment of fractured bone partially or entirely lying within the outflow tract. Although not yet accepted principles, these 3 criteria are based on a review of the literature for criteria that have been used previously to diagnose NFOT injury radiographically. Coronal and sagittal views were inspected before axial cuts to avoid bias of NFOT injury based on fracture patterns. Treatments included observation, reconstruction with outflow tract and mucosal preservation, obliteration, osteoneogenesis, and cranialization. Treatment preferences depended on the surgeon’s interpretation of the computed tomogram at the time, including NFOT injury radiologic diagnosis (degree of posterior table displacement, associated naso-orbitoethmoid fracture) or by intraoperative means. Patient exclusion criteria included patients with incomplete radiographic (unable to assess the 3 diagnostic criteria) or clinical records, patients who expired within

FIGURE 1. Frontal sinus fracture treatment algorithm. All complications but 1 in the present series had nasofrontal outflow tract injury present. Nasofrontal outflow tract injury was diagnosed by at least 1 of the following criteria: fracture in the floor of the sinus, fracture of the anterior ethmoid cells, and frank obstruction. Other commonly used criteria for degree of surgical intervention (eg, cerebrospinal fluid leak, posterior table involvement, comminution) were not statistically relevant or powerful enough to play a role in the algorithm. Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

2716

FRONTAL SINUS FRACTURE DIAGNOSIS

FIGURE 2. Frontal sinus fracture patterns (arrows) according to the table involved in axial views: A, anterior nondisplaced, B, anterior displaced, C, posterior nondisplaced, D, posterior displaced, E, simultaneous anterior-posterior nondisplaced, and F, simultaneous anteriorposterior displaced. Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

48 hours without treatment, and patients who underwent decompressive craniectomies without subsequent frontal sinus surgery. Acute major complications included cerebral spinal fluid leak, abscess, sinusitis, meningitis, mucocele, persistent pneumocephalus, and need for operative management of frontal sinus injury within 6 months after admission. Minor complications included wound drainage, infections, or cerebral spinal fluid leak that did not require surgical treatment and late contour irregularity or plate removal for palpability or visibility. Statistical analyses discriminated between patients with and without complications undergoing frontal sinus treatment by receiver operator characteristic (ROC) area under the curve (AUC) software (JMP 7.0.1; SAS Institute Inc, Cary, NC). The ROC AUC

indicates the most statistically accurate treatment management based on complications from each possible treatment pathway. ROC values higher than 0.75 indicate statistically significant diagnostic accuracy.

Results One thousand ninety-seven FSFs were compiled. Eight hundred fifty-seven patients were evaluated after excluding 153 patients with insufficient data and 87 deaths. On average, patients required 114 days before regaining full function and returning to work. Average follow-up was 2.8 months (range, 0 to 66 months). Fifty-nine percent of patients had surgery within 24 hours of injury and only 19% after 72 hours. Motor vehicle collision represented the majority of FSFs at 42%, 14% assaults, 10% motorcycle colli-

2717

STANWIX ET AL

FIGURE 3. A to C, Computed tomographic diagnosis of nasofrontal outflow tract injury as noted by frontal sinus floor fractures (arrows). This is 1 criterion used to diagnose nasofrontal outflow tract injury. Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

sions, 8% pedestrians struck, and 7% ballistic injuries. The remaining causes were falls and miscellaneous trauma. Table 1 (degree of NFOT injury and complications) delineates fracture type, treatment, and complications. The most common fracture pattern was simultaneous anterior-posterior displacement (38.4%) followed by anterior nondisplacement (21.5%). Sidedness or comminution did not play a role in any associations more than displacement alone. Concomitant body and facial injuries (Table 2) were categorized based on the presence of NFOT injury. NFOT-injured patients had 2 to 3 times more associated facial fractures than those without. FSFs were often found with naso-orbitoethmoid and orbital roof injuries (and more than twice as likely with NFOT involvement). Intracranial injuries, such as brain contusions, subdural and epidural hematomas, and intracranial hemorrhages, were 3 times more likely to be present in those with NFOT injury. The distribution of minor complications was almost exclusively related to surgical intervention. This list included, but was not limited to, poor contour irregularities (3%), hardware migration or palpability (2.5%), hematomas (⬍1%), and surgical site infections (2%). One type of minor complication, cerebrospinal fluid leaks (4%), did arise from observation. These self-limiting cerebrospinal leaks were always associated (100%) with a nondisplaced posterior table (likely because displaced posterior tables were surgically managed). Sixty-one major complications occurred in the study group (7.1%); all except 1 had NFOT injury (98.4%). Similarly, there was only 1 complication in a

patient in the NFOT injury group (1.6%) who lacked outflow tract obstruction. Patients lacking NFOT injury could be safely observed (no complications) and those with NFOT obstruction had the lowest complication rates with aggressive surgery (Table 1). Seventyone percent of all patients had NFOT injury, 26% met 1 criterion, 25% met 2 criteria, and 49% met all criteria. Overall, 67% of those with NFOT injury had obstruction by criteria with a 14% complication rate. A ROC AUC of 0.8621 demonstrated statistically significant diagnostic accuracy of the treatment algorithm.

Discussion Technologic advances in radiographic imaging have improved the ability to accurately identify and classify facial injuries, therefore playing a critical role in directing proper surgical management.7 As technology advances, so must interpretation of previously unrecognized fracture patterns and their relation to preoperative planning and ultimately patient outcomes. Invaluable studies on craniomaxillofacial fractures by various surgical subspecialties have evolved with technology and influenced the assessment of injury patterns to optimize patient care.3,5,26,27 The association of upper third facial injuries with the brain and the deleterious outcomes that arise from delay in proper diagnosis make accurate diagnosis imperative. Early treatment of FSFs has been proved to decrease the incidence of complications.15,22 Using evidence-based medicine, provided from a classification scheme based on a statistically validated algorithm, uniform diagnostic imaging criteria can be

2718

FIGURE 4. A, B, Demonstration of computed tomographic diagnosis of nasofrontal outflow tract injury with fracture of the medial aspect of the anterior table (anterior ethmoid cells). Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

identified that predict a need for specific surgical treatment of FSFs and the likelihood of complications. A systematic assessment of upper third facial injuries begins with knowledge of the frontal sinus anatomy. One must remember that the frontal sinus is absent or rudimentary in almost 9% of individuals and unilateral in another 10%.28 The boundaries of the

FRONTAL SINUS FRACTURE DIAGNOSIS

frontal sinus begin with its 2 walls: the anterior wall, which is stronger and thicker, that supports the supraorbital buttress, and the thinner posterior wall, which is intimate with the dura of the brain. The floor of the frontal sinus is the roof of the orbit laterally and contains the nasofrontal duct medially. This duct drains the mucous and secretions of the frontal sinus and runs from the posteromedial floor caudally to the hiatus semilunaris, just inferior to the middle meatus. Importantly, a true identifiable nasofrontal duct may only be found in 15% of all humans, with the other 85% having drainage through anterior ethmoid cells.9 Therefore, these investigators chose the term nasofrontal outflow tract for the drainage pattern of the frontal sinus. The intersinus septum, which separates the left and right cavities of the sinus, is continuous with the crista galli and cribriform plate inferiorly. A clear understanding of this intricate anatomy provides a uniform vocabulary for communication between craniomaxillofacial specialists. The anterior or posterior table may be fractured separately or simultaneously after direct impact and in turn may be displaced (⬎1 table width), nondisplaced, or comminuted (Fig 2). An accurate diagnosis of FSFs includes these criteria with sidedness, ie, left, right, or bilateral, with regard to the intersinus septum. Although sidedness and comminution must be clearly documented, they were not statistically relevant in the present analyses and thus did not play a role in the treatment algorithm. In the incidence of various fracture patterns, we found that simultaneous anterior-posterior displaced fractures were the most common (38%), followed by anterior nondisplaced fractures (21%). Only 7% of patients had isolated posterior wall fractures. Although fracture patterns are important, it is the diagnosis of NFOT injury that plays a key role in the natural history of FSFs and further delineates surgical management. Historically, surgical exploration evaluated the extent of injury and verification of NFOT involvement, whereas plain radiographs diagnosed bony involvement.29-31 CT scans delineated fracture involvement and injury and improved assessment of posterior wall and NFOT involvement (Fig 6); however, ambiguity remained. Because function is difficult to predict based on radiographic fracture patterns alone, NFOT patency has evolved over the previous 10 years to serve as the clinical substitute for select practitioners.3,17,18,32 Appropriate surgical management relies on defunctioning the sinus cavity (removing mucous producing cells by cranialization or obliteration) and separating the sinonasal communication if the outflow tract is injured. If uninjured and patent, surgery shifts to providing proper contour with open reduction and internal fixation and not pursuing the sinus cavity and its drainage. Mismanagement allows

2719

STANWIX ET AL

FIGURE 5. Nasofrontal outflow tract injury as diagnosed by the criterion of obstruction. A, Normal, uninjured, nasofrontal outflow tract (red arrow). B, Diagnosis of nasofrontal outflow tract injury by gross obstruction in coronal views (white arrows in A and B). C, Artist’s rendition. Diagnosis of obstruction is the key element in the present algorithm and was involved in all but 1 complication in those with nasofrontal outflow tract injury (98.4%). Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

for continuous mucous production in the absence of proper drainage, leading to infected mucoceles or mucopyoceles, recurrent sinusitis, meningitis, and even fatal brain abscesses.16,17 Surgical management depends deeply on whether the outflow tract is patent or injured. Overall in the present series, NFOT injury was present in all except 1 complication (98.4%) that arose. With NFOT injury noted as 13% to 55% in the surgical literature15,19 and 71% in the

present series (likely due to the larger percentage of simultaneous anterior-posterior injuries seen at R Adams Cowley Shock Trauma Center), radiographic determination is crucial to surgical management. The assessment of NFOT injury from CT images is limited and varies among surgeons, but most assessments depend on 1 of 3 indicators of NFOT injury: gross outflow tract obstruction (fracture fragments lying in the tract), frontal sinus floor fracture, or

Table 1. DEGREE OF NFOT INJURY AND COMPLICATIONS

Treatment Observation Reconstruction (sinus preserved) Osteoneogenesis Obliteration Cranialization NFOT Total

Complications, Complication if Obstruction, and NFOT No. of Subjects Complications Obstructed Obstructed Other Criteria ⫺ ⫹ ⫺ ⫹ ⫺ ⫹ ⫺ ⫹ ⫺ ⫹ ⫺ ⫹

222 131 15 83 1 21 7 169 6 202 251 606 857

0 (0%) 11 (8.4%) 1 (6.7%) 8 (9.6%) 0 (0%) 9 (42.9%) 0 (0%) 15 (8.9%) 0 (0%) 17 (8.4%) 1 (0.4%) 60 (9.9%) 61 (7.1%)

16 (12%)

63%

100%

11 (13%)

73%

100%

20 (95%)

45%

56%

164 (97%)

9%

10%

196 (97%)

9%

9%

407 (67%)

14%

15%

Abbreviations: ⫺, absent; ⫹, involved/injured; NFOT, nasofrontal outflow tract. NOTE. There were 83 patients with NFOT injury treated by reconstruction, with 8 complications (9.6%). Eleven patients treated by reconstruction had a diagnosis of NFOT obstruction (13%). Of these patients with obstruction, 73% had a complication rate, and if a second criterion was used (anterior ethmoidal fracture or floor fracture), then there was a 100% complication rate. Thus, those with obstruction should not be treated by reconstruction (likewise for observation and osteoneogenesis). This is 1 arm of the algorithm shown in Figure 1. Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

2720

FRONTAL SINUS FRACTURE DIAGNOSIS

Table 2. CONCOMITANT INJURIES IN FRONTAL SINUS FRACTURES

Injury Orbital roof Orbital wall Orbital floor NOE Zygoma Le Fort Mandible Intracranial Cervical spine Upper extremity fracture Lower extremity fracture Pneumothorax Abdominal

NFOT Uninjured NFOT Injured 13% 7% 2% 12% 8% 2% 3% 31% 7% 15% 13% 12% 7%

40% 13% 7% 31% 18% 17% 5% 76% 14% 25% 23% 24% 13%

Abbreviations: NFOT, nasofrontal outflow tract; NOE, nasoorbitoethmoid complex. Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

anterior table medial wall fracture (anterior ethmoid cells).32-34 These predictive criteria can be traced to the anatomy of the frontal sinus as described earlier. The nasofrontal duct (if present) or communication with anterior ethmoid cells lies in the posteromedial floor of the sinus. The anterior ethmoid cells drain over 85% of frontal sinuses, with fractures leading to impediment of mucous outflow. Gross outflow tract obstruction by fracture fragments would clearly denote injury and hinder outflow. Radiographic assessment of the 3 criteria for NFOT injury relies on imaging in all 3 planes. Fracture in the floor of the sinus can be seen best with sagittal and coronal views, anterior ethmoid cell injury with coronal more than axial views, and obstruction best with the coronal view (occasionally axial). NFOT injury can be diagnosed by 1 of these indicators, but no one has examined all 3 in relation to each other, the degree of NFOT injury (how many indicators present), or their individual relation to patient outcomes. Thus, although NFOT injury has become the cornerstone of some limited treatment algorithms, the extent of injury, in relation to complications, has heretofore not been well established. Through statistical analyses (ROC AUC), we found that obstruction played the most important role in complications; more than 97% of complications encountered had obstruction of the NFOT. Furthermore, other commonly used criteria for initiation and degree of surgical intervention (eg, cerebrospinal fluid leak, posterior table involvement, comminution) were not statistically relevant or powerful to play a role in the present algorithm. Throughout this study of more than 1,000 patients, accurate radiologic diagnoses were made of anterior table fractures and often posterior tables (91% and

79%, respectively). Only a few reported a fracture in the floor of the sinus, if present (9%). None of the reports described sole anterior ethmoidal injury, which is not synonymous with naso-orbitoethmoid complex fractures. Also, none of the reports noted obstruction of the NFOT (or nasofrontal duct for that matter), which is the most important of all criteria. It is essential that there is strict uniformity in the evaluation of CT scans and description of FSF patterns. Therefore, it would be ideal for radiologists to use the above-mentioned common terminology and facilitate patient care by diagnosing NFOT injury, particularly obstruction. Furthermore, the uncovering of an FSF in the trauma bay must heighten the awareness of intracranial or associated midface injuries. Specific FSF patterns necessitate supplementary detailed CT evaluation of the 3 indicators of NFOT injury. If at least 1 of the criteria of NFOT injury is positive, then this correlates with a 2- to 3-fold increase in facial and intracranial injuries (Table 2). For example, a nondisplaced simultaneous anterior-posterior fracture can often be classified as minimally important in a patient with massive trauma. However, as shown in the present data, posterior wall involvement, particularly with NFOT injury, is strongly associated with intracranial injury and additional facial fractures. Also, a nondisplaced posterior wall fracture may be underestimated but does dramatically increase the risk of a cerebrospinal leak. Delicate neurologic examination and communication with the appropriate trauma service must be performed promptly to ensure immediate and aggressive surgical management and full patient workup. This retrospective study provided important diagnostic criteria for FSF but does have limitations. Due to the inherent nature of this urban patient population, long-term follow-up and compliance were often unachievable; this is important because complications may arise years after injury. In addition, the low incidence of FSFs requires a long period of data collection with multiple surgeons to power a statistically relevant study. Therefore, these data are derived from different craniomaxillofacial surgeons in the same institution with very similar, but not identical, techniques over a prolonged period. Furthermore, as one would expect during this period, the quality of images reviewed did change due to technologic advances. However, images of inadequate diagnostic quality were omitted from the study. Overall, this study has the unavoidable limitations of a condition with a low incidence but provides important statistically validated radiographic criteria that enhance management of FSFs. Importantly, prospective clinical trials based on these radiographic diagnostic criteria are

2721

STANWIX ET AL

FIGURE 6. An unrestrained passenger in a vehicle involved in a head-on motor vehicle collision. This patient has a simultaneous anterior-posterior displaced fracture on A, axial image and B, 3-dimensional reconstruction. The patient meets all criteria for nasofrontal outflow tract injury: C, fracture in the floor (arrow) and D, fracture of anterior ethmoid cells (red arrow) and frank obstruction (green arrow). Stanwix et al. Frontal Sinus Fracture Diagnosis. J Oral Maxillofac Surg 2010.

being performed to confirm data and algorithm accuracy. With modernization of fracture treatments by surgeons based on new radiographic criteria, it is imperative that craniomaxillofacial surgeons recognize new critical radiographic findings in FSFs. Uniform terminology and the inclusion of critical NFOT diagnostic criteria, particularly obstruction, will decrease deleterious and potentially fatal complications associated

with FSFs. Patients with obstruction of the NFOT have more serious injuries and require prompt, aggressive surgical management (ie, cranialization over open reduction and internal fixation).

References 1. Holmgren EP, Dierks EJ, Homer LD, et al: Facial computed tomography use in trauma patients who require a head computed tomogram. J Oral Maxillofac Surg 62:913, 2004

2722 2. Kreipke DL, Moss JJ, Franco JM, et al: Computed tomography and thin-section tomography in facial trauma. AJR Am J Roentgenol 142:1041, 1984 3. Manson PN, Markowitz B, Mirvis S, et al: Toward CT-based facial fracture treatment. Plast Reconstr Surg 85:202, 1990 4. Miglietta MA, Bernstein MP: CT evaluation of frontodiagonal skull base fracture. J Trauma 60:684, 2006 5. Zimmerman RA, Bilaniuk LT, Gennarelli T, et al: Cranial computed tomography in diagnosis and management of acute head trauma. AJR Am J Roentgenol 131:27, 1978 6. Rhea JT, Rao PM, Novelline RA: Helical CT and three-dimensional CT of facial and orbital injury. Radiol Clin North Am 37:489, 1999 7. Hopper RA, Salemy S, Sze RW: Diagnosis of midface fractures with CT: What the surgeon needs to know. Radiographics 26:783, 2006 8. Gerbino G, Roccia F, Benech A, et al: Analysis of 158 frontal sinus fractures: Current surgical management and complications. J Craniomaxillofac Surg 28:133, 2000 9. Rohrich RJ, Hollier LH: Management of frontal sinus fractures. Changing concepts. Clin Plast Surg 19:219, 1992 10. Wilson BC, Davidson B, Corey JP, et al: Comparison of complications following frontal sinus fractures managed with exploration with or without obliteration over 10 years. Laryngoscope 98:516, 1988 11. Duvall AJ III, Porto DP, Lyons D, et al: Frontal sinus fractures. Analysis of treatment results. Arch Otolaryngol Head Neck Surg 113:933, 1987 12. Wallis A, Donald PJ: Frontal sinus fractures: A review of 72 cases. Laryngoscope 98:593, 1988 13. Nahum AM: The biomechanics of maxillofacial trauma. Clin Plast Surg 2:59, 1975 14. Nahum AM: The biomechanics of facial bone fracture. Laryngoscope 85:140, 1975 15. Chen KT, Chen CT, Mardini S, et al: Frontal sinus fractures: A treatment algorithm and assessment of outcomes based on 78 clinical cases. Plast Reconstr Surg 118:456, 2006 16. Larrabee WF Jr, Travis LW, Tabb HG: Frontal sinus fractures— Their suppurative complications and surgical management. Laryngoscope 90:1810, 1980

FRONTAL SINUS FRACTURE DIAGNOSIS 17. Wolfe SA, Johnson P: Frontal sinus injuries: Primary care and management of late complications. Plast Reconstr Surg 82:781, 1988 18. Rohrich RJ, Hollier L: The role of the nasofrontal duct in frontal sinus fracture management. J Craniomaxillofac Trauma 2:31, 1996 19. Yavuzer R, Sari A, Kelly CP, et al: Management of frontal sinus fractures. Plast Reconstr Surg 115:79, 2005 20. Ioannides C, Freihofer HP: Fractures of the frontal sinus: Classification and its implications for surgical treatment. Am J Otolaryngol 20:273, 1999 21. Luce EA: Frontal sinus fractures: Guidelines to management. Plast Reconstr Surg 80:500, 1987 22. Shen BH, Fang RH, Lin JT: Management of frontal sinus fractures. J Plast Reconstr Surg Assoc ROC 6:25, 1997 23. Dee KE, Newell DW, Cohen WA: Subdural empyema after depressed frontal sinus fracture. AJR Am J Roentgenol 170:790, 1998 24. Keay DG, Dale BA, Murray JA: Long-term complications of frontal sinus fractures. J R Coll Surg Edinb 33:95, 1988 25. Rath SA, Knoringer P: Late brain abscess years after severe cerebrocranial trauma with fronto-orbitobasal fracture. Childs Nerv Syst 5:121, 1989 26. Markowitz BL, Manson PN: Panfacial fractures: Organization of treatment. Clin Plast Surg 16:105, 1989 27. Zilkha A: Computed tomography in facial trauma. Radiology 144:545, 1982 28. McLaughlin RB, Jr, Rehl RM, Lanza DC: Clinically relevant frontal sinus anatomy and physiology. Otolaryngol Clin North Am 34:1, 2001 29. Bergara AR, Itoiz AO: Present state of the surgical treatment of chronic frontal sinusitis. AMA Arch Otolaryngol 61:616, 1955 30. Donald PJ, Bernstein L: Compound frontal sinus injuries with intracranial penetration. Laryngoscope 88:225, 1978 31. Lynch RC: The technique of radical frontal sinus operation which has given me the best results. Laryngoscope 31:1, 1921 32. Harris L, Marano GD, McCorkle D: Nasofrontal duct: CT in frontal sinus trauma. Radiology 165:195, 1987 33. Heller EM, Jacobs JB, Holliday RA: Evaluation of the frontonasal duct in frontal sinus fractures. Head Neck 11:46, 1989 34. Landsberg R, Friedman M: A computer-assisted anatomical study of the nasofrontal region. Laryngoscope 111:2125, 2001