ORIGINAL ARTICLE
Facial Fractures of the Upper Craniofacial Skeleton Predict Mortality and Occult Intracranial Injury After Blunt Trauma: An Analysis Justin L. Bellamy, BS,* Gerhard S. Mundinger, MD,Þ Jose´ M. Flores, MPH,*þ Sashank K. Reddy, MD, PhD,Þ Suhail K. Mithani, MD,§ Eduardo D. Rodriguez, MD, DDS,Þ and Amir H. Dorafshar, MBChB, FAAP*Þ
Purpose: The aim of this article was to assess how regional facial fracture patterns predict mortality and occult intracranial injury after blunt trauma. Methods: Retrospective chart review was performed for bluntmechanism craniofacial fracture patients who presented to an urban trauma center from 1998 to 2010. Fractures were confirmed by author review of computed tomographic imaging and then grouped into 1 of 5 patterns of regional involvement representing all possible permutations of facial-third injury. Mortality and the presence of occult intracranial injury, defined as those occurring in patients at low risk at presentation for head injury by Canadian CT Head Rule criteria, were evaluated. Relative risk estimates were obtained using multivariable regression. Results: Of 4540 patients identified, 338 (7.4%) died, and 171 (8.1%) had intracranial injury despite normal Glasgow Coma Scale at presentation. Cumulative mortality reached 18.8% for isolated upper face fractures, compared with 6.9% and 4.0% for middle and lower face fractures (P G 0.001), respectively. Upper face fractures were independently associated with 4.06-, 3.46-, and 3.59-fold increased What Is This Box? A QR Code is a matrix barcode readable by QR scanners, mobile phones with cameras, and smartphones. The QR Code links to the online version of the article.
From the *Johns Hopkins School of Medicine; †Division of Plastic and Reconstructive Surgery, R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine; and ‡Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland; and §Division of Plastic and Reconstructive Surgery, Duke University, Durham, North Carolina. Received April 11, 2013. Accepted for publication June 30, 2013. Address correspondence and reprint requests to Amir H. Dorafshar, MBChB, FAAP, Plastic, Reconstructive, and Maxillofacial Surgery, R. Adams Cowley Shock Trauma Center, Room P1G04K, 22 S Greene St, Baltimore, MD 21201; E-mail address: [email protected] This study has no sources of support and funding requiring acknowledgement. Presented in part at the 57th Annual Meeting of the Plastic Surgery Research Council, June 15, 2012, Ann Arbor, Michigan. The authors report no conflicts of interest. Copyright * 2013 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0b013e3182a30544
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risk of death for the following fracture patterns: isolated upper, combined upper, panfacial, respectively (P G 0.001). Patients who were at low risk for head injury remained 4 to 6 times more likely to suffer an occult intracranial injury if they had involvement of the upper face. Conclusions: The association between facial fractures, intracranial injury, and death varies by regional involvement, with increasing insult in those with upper face fractures. Cognizance of the increased risk for intracranial injury in patients with upper face fractures may supplement existing triage tools and should increase suspicion for underlying or impending neuropathology, regardless of clinical picture at presentation. Key Words: Facial fracture, blunt trauma, craniofacial trauma, neurologic injury, intracranial injury, death, computed tomography (J Craniofac Surg 2013;24: 1922Y1926)
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evere facial trauma is associated with intracranial injury and death.1Y10 Prior investigations suggest that the magnitude of this association may vary by facial-third regional involvement.2,3,11 Because of the relative rarity of subgroups with specific regional involvement (eg, panfacial or isolated upper face), attempts to evaluate these associations have been primarily descriptive or involved only simple statistical tests or unadjusted univariate analyses.1,2 To fully evaluate the independent effect of these fractures on mortality across specific fracture patterns, multivariable analysis of a large data set with sufficient detail and resolution is required. The purpose of this study was to evaluate the associations of various regional facial fracture patterns with death and occult intracranial injury. We hypothesized that patients with superiorly located facial fracture patterns would be more likely to die during hospitalization. In addition, we hypothesized that these patients would be more likely to possess intracranial injury, even with a normal presenting Glasgow Coma Scale (GCS) score. The specific aim of the present study was to compare and quantify these associations in the context of existing trauma triage tools to improve risk stratification.
MATERIALS AND METHODS We designed and implemented an institutional review boardY approved retrospective cohort study adherent to Helsinki Declaration guidelines. The study population was composed of patients presenting to R. Adams Cowley Shock Trauma Center for management of blunt-mechanism craniofacial fractures between 1998 and 2010. To be included in the study, patients had to have experienced blunt trauma resulting in fracture of the facial skeleton. Patients with penetrating or nonbony facial trauma were excluded from this study.
The Journal of Craniofacial Surgery
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Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
& Volume 24, Number 6, November 2013
TABLE 1. Individual Fracture Grouping Facial Region Upper Middle Lower
Included Fractures Supraorbital rim, orbital roof, and frontal sinus fractures Maxillary, zygomatic, other orbital (medial, floor, and lateral wall), ethmoidal, and dentoalveolar fractures Any mandibular fracture (condylar, subcondylar, coronoid, ramus, angle, body, parasymphyseal, or symphyseal)
Blunt-mechanism facial fractures and intracranial injury outcomes were identified using the International Classification of Diseases, Ninth Revision codes. Admission history and physical examinations, radiographic studies, documented hospitalization course, and medical examiner reports were reviewed to confirm all identified information. Baseline characteristic data collected for each identified patient included age, sex, mechanism of injury, injury severity score (ISS),12 and admission GCS score. Craniofacial imaging was directly reviewed by the authors to document fractures and confirm recorded diagnoses.6,7,13 Facial fractures were classified according to anatomic location by facial thirds (Table 1, Fig. 1A). The primary predictor variable was composite regional fracture pattern. Composite regional fracture pattern groups were generated by assigning each patient to 1 of 5 regional fracture patterns corresponding to their injuries: (1) isolated upper, (2) upper with one additional region, (3) panfacial (involvement of all facial thirds),14 (4) middle (isolated or with lower), and (5) isolated lower face fracture (Fig. 1B). To have a relative comparison of severity, isolated nasal fractures were selected as the reference group because this was the least clinically severe injury in this cohort.
Death After Blunt Facial Fracture
Death during hospitalization was the primary outcome variable. The secondary outcome, intracranial injury, included epidural, subdural, subarachnoid, and intraparenchymal bleeds, as well as brainstem injury (laceration or herniation). To evaluate the association between fractures and intracranial injury in a manner that might be most clinically useful, we performed regression analysis for intracranial injury among patients with the least clinically apparent neurologic impairment. Evaluation of these occult intracranial injuries was accomplished by subgroup analysis in those patients who would, insofar as was possible with our trauma registry, qualify as ‘‘low-risk’’ for head injury by the Canadian CT Head Rule.15 These patients had an admission GCS score of 15, were between the ages of 16 and 64 years, were without evidence of skull base injury, and did not suffer a high-risk mode of injury, defined as a pedestrian struck or fall from elevation.
Statistical Analysis Baseline characteristics between populations were compared using the 2-sample t test for continuous variables. For categorical variables, a W2 or Fisher exact test was used. We analyzed the crude effects of our exposure on each outcome by building univariate unadjusted models. Variables were selected for inclusion in the final multivariable regression analysis if they were statistically significantly (P G 0.05) associated with both the exposure (fracture pattern) and the outcome (death/occult intracranial injury). This exploratory analysis resulted in consideration of the following confounders: age, Abbreviated Injury Scale (AIS) score for noncraniofacial regions (includes neck, spine, abdomen,
FIGURE 1. A, Facial-third regional fracture classification. B, Composite facial fracture pattern analysis groups.
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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thorax, upper extremity, lower extremity scores; excludes head and face scores),12 and mode of injury. Noncraniofacial AIS scores were selected in place of ISS scores as a measure of trauma severity because face and head AIS scores (components of the ISS) are directly tied to the primary exposure (facial fracture) and result in statistical colinearity. We assumed that the triage tools GCS score and ISS/AIS were all measures of the same confounder (patient acuity/injury severity), further supported by their correlation (r coefficient = 0.6). Therefore, only AIS scores were included in the final model to avoid overadjustment. The independent effect of each fracture pattern on each outcome was estimated using multivariable regression models using the Poisson distribution to control for confounding. All statistical analyses were performed with the use of STATA/ MP software, version 12 (StataCorp, College Station, TX).
RESULTS Between 1998 and 2010, we identified 4540 patients with blunt-mechanism facial fractures. A total of 986 patients (21.7%) had isolated nasal fractures, and 3554 (78.3%) had one of the composite regional facial fracture patterns. Of the composite regional patterns, there were 518 isolated lower face (14.6%), 2308 middle face (64.9%), 117 isolated upper face (3.3%), 542 combined upper face (15.3%), and 69 panfacial fractures (1.9%). Baseline characteristics for those who suffered a regional fracture pattern compared with those who suffered isolated nasal fractures are shown in Table 2. On average, patients who suffered one of the regional fracture patterns tended to be statistically, although not clinically, older (38.8 vs 38.2 years, P G 0.001), had an increased proportion of African Americans (P G 0.001), had higher ISSs, and lower admission GCS scores (P G 0.001). Injury as the result of being a pedestrian struck more often resulted in one of the regional fracture patterns (P G 0.005), whereas those in motor vehicle collisions more often had isolated nasal fractures (P G 0.001).
Death A total of 338 patients (7.4%) died during their hospitalization. The cumulative incidence of death was 18.8% for isolated upper face, 16.8% for combined upper face, 17.4% for panfacial,
TABLE 2. Baseline Characteristics
Demographics Age* (mean), y Sex,* % male White race,* % Black race,* % Other race, % Measures of severity ISS* (mean) Admit GCS score* (mean) Mode of injury MVC,* % Motorcycle, % Pedestrian struck,* % Assault, % Fall, % All other,* %
TABLE 3. Univariate Regression* Death
RR Regional fracture pattern Isolated nasal Isolated upper Combined upper Panfacial Middle Isolated lower Mode of injury MVC Motorcycle Pedestrian struck Assault Fall Other Measures of severity Admission GCS score (per point) ISS (per point) Demographic factors Age Q65 y White race Black race Female sex
95% Confidence Interval
P
Reference (control) group 5.45 4.87 5.04 1.99 1.18
V
V
3.30Y9.00 3.33Y7.12 2.74Y9.29 1.38Y2.86 0.69Y2.00
G0.001 G0.001 G0.001 G0.001 0.552
1.19 1.06 2.58 0.17 1.68 1.24
0.97Y1.46 0.67Y1.68 1.98Y3.38 0.11Y0.27 1.32Y2.14 0.70Y2.20
0.100 0.791 G0.001 G0.001 G0.001 0.464
0.77 1.07
0.75Y0.79 1.07Y1.07
G0.001 G0.001
5.57 1.66 0.54 1.31
4.58Y6.78 1.32Y2.10 0.41Y0.70 1.04Y1.65
G0.001 G0.001 G0.001 G0.05
MVC indicates motor vehicle collision.
6.9% for middle, 4.0% for isolated lower, and 3.5% for isolated nasal fractures (P G 0.001). The results of univariate regression analysis for each pattern and other important predictors are listed in Table 3. Of note, sustaining a blunt facial fracture at an elderly age, as a pedestrian struck, or from a fall was all significantly associated with death (P G 0.001), whereas those sustaining facial fractures from blunt assault were less likely to die (P G 0.001). Although the racial and sex composition differed significantly between those who suffered a regional fracture pattern and those who suffered an isolated nasal fracture (Table 2) and appeared
Isolated Nasal, n = 986
Regional Pattern, n = 3554
P
38.2 73.4 68.1 25.8 6.2
38.8 78.3 59.8 32.2 8.0
G0.001 G0.001 G0.001 G0.001 0.054
TABLE 4. Multivariable Regression*
11.9 13.9
19.1 12.4
G0.001 G0.001
47.7 4.1 4.8 26.7 13.5 1.7
38.8 5.3 7.4 28.1 15.1 2.9
G0.001 0.115 G0.005 0.391 0.215 G0.05
Regional fracture pattern Isolated nasal, n = 986 Isolated upper, n = 117 Combined upper, n = 542 Panfacial, n = 69 Middle, n = 2308 Isolated lower, n = 518
*Significant. MVC indicates motor vehicle collision. Categorical variables compared by W2 test, continuous variables compared by 2-sided Student t test.
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Death
RR
95% Confidence Interval
P
Cumulative Incidence
Reference (control) group 4.06
V
V
3.5%
2.62Y6.30
G0.001
18.8%
3.46
2.43Y4.94
G0.001
16.8%
3.59 1.63 1.21
2.01Y6.40 1.18Y2.25 0.74Y1.99
G0.001 G0.005 0.448
17.4% 6.9% 4.0%
*Adjusted for age, mode of injury, and severity of other bodily injuries.
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
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associated with death on univariate analysis (Table 3), neither significantly predicted death after adjustment for age and mode of injury. Multivariable regression results for death are shown in Table 4. After adjustment, composite regional fracture patterns involving the upper face (isolated upper: relative risk [RR], 4.06; combined upper: RR, 3.46; panfacial: RR, 3.59; all at P G 0.001) or middle face (RR, 1.63; P G 0.005) were independently associated with death to varying degrees. Isolated lower face fractures were not significantly more associated with death than isolated nasal fractures (P = 0.448). In addition, there was a stepwise increase in risk for death with more superior facial involvement: isolated upper face fractures were 2.49-fold (P G 0.001), combined upper face fractures 2.12-fold (P G 0.001), and panfacial fractures were 2.20-fold (P G 0.005) more likely to die than middle face fractures. Of note, however, middle face fractures were not significantly different from lower face fracture on direct pairwise comparison (RR, 1.06; 95% confidence interval, 0.67Y1.70; P = 0.796).
Occult Intracranial Injury In total, 2103 blunt-mechanism facial fracture patients (46.4%) were considered at low risk for intracranial injury by the evaluated Canadian CT Head Rule criteria. Of these, 171 (8.1%) still suffered underlying intracranial injury. The cumulative incidence of intracranial injury despite being at ‘‘low risk’’ was 33.3%, 24.2%, and 22.0% for panfacial, combined upper, and isolated upper face fractures, respectively; in contrast, the cumulative incidence of intracranial injury among middle and isolated lower face fractures was 7.5% and 3.6%, respectively (df = 5, P G 0.001). Adjusted analysis revealed that, in patients who were otherwise at low risk for head injury, fracture patterns involving the upper face were significantly more associated with occult intracranial injury (Table 5). Specifically, there was a 4.12-fold (P G 0.001), 4.55-fold (P G 0.001), and 6.26-fold (P G 0.001) increased risk of sustaining an underlying intracranial injury with isolated upper, combined upper, or panfacial fractures, respectively. Although neither middle nor lower face fractures were significantly associated with intracranial injury (P = 0.097 and P = 0.254, respectively) when compared with isolated nasal fractures, there were still some important differences between these groups. The cumulative rates of intracranial injury after middle face and isolated nasal fractures were 7.5% and 5.3%, respectively, compared with 3.6% after lower face fracture. In a direct, adjusted pairwise comparison between middle face fracture and lower face fracture,
TABLE 5. Stratified Regression*: ‘‘Low Risk’’ on Canadian CT Head Rule* Occult Intracranial Injury
RR Regional fracture pattern Isolated nasal, n = 563 Reference (control) group Isolated upper, n = 41 4.12 Combined upper, 4.55 n = 161 Panfacial, n = 15 6.26 Middle, n = 1022 1.41 Isolated lower, n = 306 0.67
95% Confidence Interval
V
P
V
Incidence
5.3%
2.10Y8.08 2.92Y7.08
G0.001 G0.001
22.0% 24.2%
2.82Y13.87 0.94Y2.13 0.34Y1.33
G0.001 0.097 0.254
33.3% 7.5% 3.6%
*Confounding accounted for by stratification on available Canadian CT Head Rule criteria: aged 16 to 64 years, GCS score of 15, without basilar fracture, without a highrisk mechanism of injury (pedestrian struck or fall from elevation).
Death After Blunt Facial Fracture
middle face fractures were 2.10-fold more likely to have occult intracranial injury (P G 0.05) than lower face fractures.
DISCUSSION The purpose of this study was to evaluate the strength of the associations of various complex facial fracture patterns with mortality and occult intracranial injury. Clinical experience and several studies2,3,11,16 have suggested that rates of death and intracranial injury may vary by regional involvement and fracture pattern. We hypothesized that superiorly located facial fracture patterns would be more likely to die during hospitalization. The specific aim of the present study was to measure the association between several regional facial fracture patterns and death. In addition, to improve the clinical utility of our findings, we sought to investigate rates of intracranial injury by fracture pattern in those patients who may not otherwise be immediately suspected of having underlying or impending neurologic pathology. Although multiple studies have drawn attention to specific concomitant injuries with middle and lower face fractures,3,6,17 we found that facial fractures became strikingly associated with mortality and occult intracranial injury as more superior facial regions became involved. Specifically, compared with an isolated nasal fracture in similar patients, lower face fractures were not significantly associated with death, whereas sustaining a midface fracture was independently associated with a greater than 63% increased risk of death (P G 0.005); furthermore, all fracture patterns that involved the upper face were 3 to 4 times more likely to result in death during hospitalization. In the pairwise comparison of upper face fracture directly to middle face fracture, death was still more than twice as likely to occur if there was any involvement of the upper facial skeleton, indicating a stepwise increase in mortality with more superior facial involvement. Of the upper face fracture patterns, isolated upper face fracture had both the highest absolute risk and RR of death even after adjusting for important confounders. Although mortality rates between these upper face patterns did not significantly differ from one another, there is some evidence in this series that focused force delivery to the superior facial skeleton may be the most fatal. We further explored differences in rates of intracranial injury by fracture pattern as neurologic injury remains the most apparent mediator of death in craniofacial polytrauma patients. Because most institutions in the United States practice a low threshold for performing head computed tomography imaging in blunt facial trauma patients, to improve the clinical utility of our findings we limited our analysis to those who were fully alert and oriented and were otherwise at ‘‘low risk’’ for head injury by the available Canadian CT Head Rule criteria. We found that, even without alteration in alertness, and with a clinical picture that may not be immediately alarming for intracranial injury, those with trauma to the upper face were profoundly more likely to have occult intracranial injury. There was a direct correlation with proximity to the neurocranium and intracranial injury: occult intracranial injury occurred more often after upper face injury than middle and more often with middle face than lower. Taken together, these data support the need for careful imaging and monitoring for serious underlying or evolving neurologic insult in patients suspected of having injury to the superior facial skeleton, regardless of clinical picture at presentation. The average injury severity (ISS, 17.4), age (38.7 years), male predominance (77.3%), and mode of injury distribution in this series are consistent with previous reports,1,11,18 supporting the generalizability of our findings to other institutions. All fractures were confirmed by author review of craniofacial imaging to ensure accurate reporting of each fracture pattern.6,7,19 In addition, in contrast to the overwhelming majority of literature on this topic,
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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this article reports RRs that, unlike odds ratios, are directly translatable to actual-fold increases in risk. Finally, the large sample size in this series (ntotal = 4540, ndeath = 338, nintracranial injury = 1185) afforded us greater power at higher resolution to isolate the effect of individual pattern subgroups for specific outcomes while adjusting for the strongest confounders with multivariable modeling. Our finding that injury to the upper face was most strongly predictive of intracranial injury and death is consistent with previous investigations.2,11,20 In the past, this has been attributed to the combination of increased force required to fracture these areas and the effect of direct force transmission to the neurocranium.2,17,21 We have added to the existing literature by isolating the independent contribution that each regional fracture pattern has on morrtality while adjusting for the most important confounders in a multivariable model. Furthermore, we explored the ability of these fracture patterns to predict intracranial injury in the fully alert patient with a clinical picture that may not be immediately alarming for underlying or evolving intracranial injury. Understanding the relationship that specific facial fracture patterns have with intracranial injury in this group of patients may expedite identification of existing or impending intracranial insult. Our hope is to provide higher-resolution risk stratification to aid early identification of evolving injuries to supplement existing triage tools (eg, GCS score, Canadian CT Head Rule, etc) where they may fail to appropriately alert the provider. In addition, we have included our model specification, and statistics of interest including the RRs, SEs, the subgroup sample size for each facial fracture, and all estimates related to the confounders of the association with mortality. These types of estimates are essential for the future design of systematic reviews and meta-analyses with even more robust precision. We acknowledge some study limitations that should be considered when interpreting our results. This was a retrospective study using data extracted from a large, single institutional database that is reliant upon accurate data entry over a broad period of time. Furthermore, this study was undertaken at a high-volume urban trauma institute where regional referral patterns result in a patient population with more severe injuries than those that may be encountered in other centers. In our exploration of intracranial injury risk with minor head trauma, the resolution of the trauma registry and patient documentation did not allow us to confirm every criteria of the Canadian CT Head Rule. However, the most clinically apparent criteria were available and included.
CONCLUSIONS A thorough understanding of the increased morbidity and mortality conferred by specific patterns of craniofacial injury may improve early identification of the most critically ill patients and lead to greater efficiency in their management. In this series, we observed that mortality rates are directly related to proximity of the involved regional subunits to the neurocranium and quantified the independent contributions of these fractures. Furthermore, we found that even in the fully alert patient who is otherwise at low risk for head injury, any involvement of the upper facial skeleton is highly associated with underlying occult intracranial injury. These patients should be managed with heightened vigilance and followed closely during hospitalization with a low threshold for serial imaging, regardless of presenting clinical picture.
ACKNOWLEDGMENTS The authors thank J. Alex Kelamis, MD, and Michael R. Christy, MD, for their significant contributions to project conception and data collection.
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1. Hohlrieder M, Hinterhoelzl J, Ulmer H, et al. Maxillofacial fractures masking traumatic intracranial hemorrhages. Int J Oral Maxillofac Surg 2004;33:389Y395 2. Lee KF, Wagner LK, Lee YE, et al. The impact-absorbing effects of facial fractures in closed-head injuries. An analysis of 210 patients. J Neurosurg 1987;66:542Y547 3. Mithani SK, St-Hilaire H, Brooke BS, et al. Predictable patterns of intracranial and cervical spine injury in craniomaxillofacial trauma: analysis of 4786 patients. Plast Reconstr Surg 2009;123:1293Y1301 4. Sinclair D, Schwartz M, Gruss J, et al. A retrospective review of the relationship between facial fractures, head injuries, and cervical spine injuries. J Emerg Med 1988;6:109Y112 5. McCabe JB, Angelos MG. Injury to the head and face in patients with cervical spine injury. Am J Emerg Med 1984;2:333Y335 6. Mundinger G, Dorafshar A, Gilson M, et al. Blunt-mechanism facial fracture patterns associated with internal carotid artery injuries: recommendations for additional screening criteria based on analysis of 4,398 patients. J Oral Maxillofac Surg 2013; in press 7. Mundinger G, Dorafshar A, Gilson M, et al. Analysis of 8,127 radiographically confirmed blunt-mechanism facial fractures in 4,398 patients. J Craniofac Surg 2013; in press 8. Slupchynskyj OS, Berkower AS, Byrne DW, et al. Association of skull base and facial fractures. Laryngoscope 1992;102:1247Y1250 9. Tung TC, Tseng WS, Chen CT, et al. Acute life-threatening injuries in facial fracture patients: a review of 1,025 patients. J Trauma 2000;49:420Y424 10. Haug RH, Adams JM, Conforti PJ, et al. Cranial fractures associated with facial fractures: a review of mechanism, type, and severity of injury. J Oral Maxillofac Surg 1994;52:729Y733 11. Plaisier BR, Punjabi AP, Super DM, et al. The relationship between facial fractures and death from neurologic injury. J Oral Maxillofac Surg 2000;58:708Y712; discussion 712Y713 12. Baker SP, O’Neill B, Haddon W Jr, et al. The injury severity score: a method for describing patients with multiple injuries and evaluating emergency care. J Trauma 1974;14:187Y196 13. Manson PN, Markowitz B, Mirvis S, et al. Toward CT-based facial fracture treatment. Plast Reconstr Surg 1990;85:202Y212; discussion 213Y214 14. Markowitz BL, Manson PN. Panfacial fractures: organization of treatment. Clin Plast Surg 1989;16:105Y114 15. Stiell IG, Wells GA, Vandemheen K, et al. The Canadian CT Head Rule for patients with minor head injury. Lancet 2001;357:1391Y1396 16. Mulligan RP, Mahabir RC. The prevalence of cervical spine injury, head injury, or both with isolated and multiple craniomaxillofacial fractures. Plast Reconstr Surg 2010;126:1647Y1651 17. Manson PN, Stanwix MG, Yaremchuk MJ, et al. Frontobasal fractures: anatomical classification and clinical significance. Plast Reconstr Surg 2009;124:2096Y2106 18. Alvi A, Doherty T, Lewen G. Facial fractures and concomitant injuries in trauma patients. Laryngoscope 2003;113:102Y106 19. Tessier P. The classic reprint: experimental study of fractures of the upper jaw. 3. Rene Le Fort, M.D., Lille, France. Plast Reconstr Surg 1972;50:600Y607 20. Haug RH, Savage JD, Likavec MJ, et al. A review of 100 closed head injuries associated with facial fractures. J Oral Maxillofac Surg 1992;50:218Y222 21. Sturla F, Abnsi D, Buquet J. Anatomical and mechanical considerations of craniofacial fractures: an experimental study. Plast Reconstr Surg 1980;66:815Y820
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Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
Facial Fractures of the Upper Craniofacial Skeleton Predict Mortality and Occult Intracranial Injury After Blunt Trauma: An Analysis Justin L. Bellamy, BS,* Gerhard S. Mundinger, MD,Þ Jose´ M. Flores, MPH,*þ Sashank K. Reddy, MD, PhD,Þ Suhail K. Mithani, MD,§ Eduardo D. Rodriguez, MD, DDS,Þ and Amir H. Dorafshar, MBChB, FAAP*Þ
Purpose: The aim of this article was to assess how regional facial fracture patterns predict mortality and occult intracranial injury after blunt trauma. Methods: Retrospective chart review was performed for bluntmechanism craniofacial fracture patients who presented to an urban trauma center from 1998 to 2010. Fractures were confirmed by author review of computed tomographic imaging and then grouped into 1 of 5 patterns of regional involvement representing all possible permutations of facial-third injury. Mortality and the presence of occult intracranial injury, defined as those occurring in patients at low risk at presentation for head injury by Canadian CT Head Rule criteria, were evaluated. Relative risk estimates were obtained using multivariable regression. Results: Of 4540 patients identified, 338 (7.4%) died, and 171 (8.1%) had intracranial injury despite normal Glasgow Coma Scale at presentation. Cumulative mortality reached 18.8% for isolated upper face fractures, compared with 6.9% and 4.0% for middle and lower face fractures (P G 0.001), respectively. Upper face fractures were independently associated with 4.06-, 3.46-, and 3.59-fold increased What Is This Box? A QR Code is a matrix barcode readable by QR scanners, mobile phones with cameras, and smartphones. The QR Code links to the online version of the article.
From the *Johns Hopkins School of Medicine; †Division of Plastic and Reconstructive Surgery, R. Adams Cowley Shock Trauma Center, University of Maryland School of Medicine; and ‡Department of Epidemiology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland; and §Division of Plastic and Reconstructive Surgery, Duke University, Durham, North Carolina. Received April 11, 2013. Accepted for publication June 30, 2013. Address correspondence and reprint requests to Amir H. Dorafshar, MBChB, FAAP, Plastic, Reconstructive, and Maxillofacial Surgery, R. Adams Cowley Shock Trauma Center, Room P1G04K, 22 S Greene St, Baltimore, MD 21201; E-mail address: [email protected] This study has no sources of support and funding requiring acknowledgement. Presented in part at the 57th Annual Meeting of the Plastic Surgery Research Council, June 15, 2012, Ann Arbor, Michigan. The authors report no conflicts of interest. Copyright * 2013 by Mutaz B. Habal, MD ISSN: 1049-2275 DOI: 10.1097/SCS.0b013e3182a30544
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risk of death for the following fracture patterns: isolated upper, combined upper, panfacial, respectively (P G 0.001). Patients who were at low risk for head injury remained 4 to 6 times more likely to suffer an occult intracranial injury if they had involvement of the upper face. Conclusions: The association between facial fractures, intracranial injury, and death varies by regional involvement, with increasing insult in those with upper face fractures. Cognizance of the increased risk for intracranial injury in patients with upper face fractures may supplement existing triage tools and should increase suspicion for underlying or impending neuropathology, regardless of clinical picture at presentation. Key Words: Facial fracture, blunt trauma, craniofacial trauma, neurologic injury, intracranial injury, death, computed tomography (J Craniofac Surg 2013;24: 1922Y1926)
S
evere facial trauma is associated with intracranial injury and death.1Y10 Prior investigations suggest that the magnitude of this association may vary by facial-third regional involvement.2,3,11 Because of the relative rarity of subgroups with specific regional involvement (eg, panfacial or isolated upper face), attempts to evaluate these associations have been primarily descriptive or involved only simple statistical tests or unadjusted univariate analyses.1,2 To fully evaluate the independent effect of these fractures on mortality across specific fracture patterns, multivariable analysis of a large data set with sufficient detail and resolution is required. The purpose of this study was to evaluate the associations of various regional facial fracture patterns with death and occult intracranial injury. We hypothesized that patients with superiorly located facial fracture patterns would be more likely to die during hospitalization. In addition, we hypothesized that these patients would be more likely to possess intracranial injury, even with a normal presenting Glasgow Coma Scale (GCS) score. The specific aim of the present study was to compare and quantify these associations in the context of existing trauma triage tools to improve risk stratification.
MATERIALS AND METHODS We designed and implemented an institutional review boardY approved retrospective cohort study adherent to Helsinki Declaration guidelines. The study population was composed of patients presenting to R. Adams Cowley Shock Trauma Center for management of blunt-mechanism craniofacial fractures between 1998 and 2010. To be included in the study, patients had to have experienced blunt trauma resulting in fracture of the facial skeleton. Patients with penetrating or nonbony facial trauma were excluded from this study.
The Journal of Craniofacial Surgery
& Volume 24, Number 6, November 2013
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
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TABLE 1. Individual Fracture Grouping Facial Region Upper Middle Lower
Included Fractures Supraorbital rim, orbital roof, and frontal sinus fractures Maxillary, zygomatic, other orbital (medial, floor, and lateral wall), ethmoidal, and dentoalveolar fractures Any mandibular fracture (condylar, subcondylar, coronoid, ramus, angle, body, parasymphyseal, or symphyseal)
Blunt-mechanism facial fractures and intracranial injury outcomes were identified using the International Classification of Diseases, Ninth Revision codes. Admission history and physical examinations, radiographic studies, documented hospitalization course, and medical examiner reports were reviewed to confirm all identified information. Baseline characteristic data collected for each identified patient included age, sex, mechanism of injury, injury severity score (ISS),12 and admission GCS score. Craniofacial imaging was directly reviewed by the authors to document fractures and confirm recorded diagnoses.6,7,13 Facial fractures were classified according to anatomic location by facial thirds (Table 1, Fig. 1A). The primary predictor variable was composite regional fracture pattern. Composite regional fracture pattern groups were generated by assigning each patient to 1 of 5 regional fracture patterns corresponding to their injuries: (1) isolated upper, (2) upper with one additional region, (3) panfacial (involvement of all facial thirds),14 (4) middle (isolated or with lower), and (5) isolated lower face fracture (Fig. 1B). To have a relative comparison of severity, isolated nasal fractures were selected as the reference group because this was the least clinically severe injury in this cohort.
Death After Blunt Facial Fracture
Death during hospitalization was the primary outcome variable. The secondary outcome, intracranial injury, included epidural, subdural, subarachnoid, and intraparenchymal bleeds, as well as brainstem injury (laceration or herniation). To evaluate the association between fractures and intracranial injury in a manner that might be most clinically useful, we performed regression analysis for intracranial injury among patients with the least clinically apparent neurologic impairment. Evaluation of these occult intracranial injuries was accomplished by subgroup analysis in those patients who would, insofar as was possible with our trauma registry, qualify as ‘‘low-risk’’ for head injury by the Canadian CT Head Rule.15 These patients had an admission GCS score of 15, were between the ages of 16 and 64 years, were without evidence of skull base injury, and did not suffer a high-risk mode of injury, defined as a pedestrian struck or fall from elevation.
Statistical Analysis Baseline characteristics between populations were compared using the 2-sample t test for continuous variables. For categorical variables, a W2 or Fisher exact test was used. We analyzed the crude effects of our exposure on each outcome by building univariate unadjusted models. Variables were selected for inclusion in the final multivariable regression analysis if they were statistically significantly (P G 0.05) associated with both the exposure (fracture pattern) and the outcome (death/occult intracranial injury). This exploratory analysis resulted in consideration of the following confounders: age, Abbreviated Injury Scale (AIS) score for noncraniofacial regions (includes neck, spine, abdomen,
FIGURE 1. A, Facial-third regional fracture classification. B, Composite facial fracture pattern analysis groups.
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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thorax, upper extremity, lower extremity scores; excludes head and face scores),12 and mode of injury. Noncraniofacial AIS scores were selected in place of ISS scores as a measure of trauma severity because face and head AIS scores (components of the ISS) are directly tied to the primary exposure (facial fracture) and result in statistical colinearity. We assumed that the triage tools GCS score and ISS/AIS were all measures of the same confounder (patient acuity/injury severity), further supported by their correlation (r coefficient = 0.6). Therefore, only AIS scores were included in the final model to avoid overadjustment. The independent effect of each fracture pattern on each outcome was estimated using multivariable regression models using the Poisson distribution to control for confounding. All statistical analyses were performed with the use of STATA/ MP software, version 12 (StataCorp, College Station, TX).
RESULTS Between 1998 and 2010, we identified 4540 patients with blunt-mechanism facial fractures. A total of 986 patients (21.7%) had isolated nasal fractures, and 3554 (78.3%) had one of the composite regional facial fracture patterns. Of the composite regional patterns, there were 518 isolated lower face (14.6%), 2308 middle face (64.9%), 117 isolated upper face (3.3%), 542 combined upper face (15.3%), and 69 panfacial fractures (1.9%). Baseline characteristics for those who suffered a regional fracture pattern compared with those who suffered isolated nasal fractures are shown in Table 2. On average, patients who suffered one of the regional fracture patterns tended to be statistically, although not clinically, older (38.8 vs 38.2 years, P G 0.001), had an increased proportion of African Americans (P G 0.001), had higher ISSs, and lower admission GCS scores (P G 0.001). Injury as the result of being a pedestrian struck more often resulted in one of the regional fracture patterns (P G 0.005), whereas those in motor vehicle collisions more often had isolated nasal fractures (P G 0.001).
Death A total of 338 patients (7.4%) died during their hospitalization. The cumulative incidence of death was 18.8% for isolated upper face, 16.8% for combined upper face, 17.4% for panfacial,
TABLE 2. Baseline Characteristics
Demographics Age* (mean), y Sex,* % male White race,* % Black race,* % Other race, % Measures of severity ISS* (mean) Admit GCS score* (mean) Mode of injury MVC,* % Motorcycle, % Pedestrian struck,* % Assault, % Fall, % All other,* %
TABLE 3. Univariate Regression* Death
RR Regional fracture pattern Isolated nasal Isolated upper Combined upper Panfacial Middle Isolated lower Mode of injury MVC Motorcycle Pedestrian struck Assault Fall Other Measures of severity Admission GCS score (per point) ISS (per point) Demographic factors Age Q65 y White race Black race Female sex
95% Confidence Interval
P
Reference (control) group 5.45 4.87 5.04 1.99 1.18
V
V
3.30Y9.00 3.33Y7.12 2.74Y9.29 1.38Y2.86 0.69Y2.00
G0.001 G0.001 G0.001 G0.001 0.552
1.19 1.06 2.58 0.17 1.68 1.24
0.97Y1.46 0.67Y1.68 1.98Y3.38 0.11Y0.27 1.32Y2.14 0.70Y2.20
0.100 0.791 G0.001 G0.001 G0.001 0.464
0.77 1.07
0.75Y0.79 1.07Y1.07
G0.001 G0.001
5.57 1.66 0.54 1.31
4.58Y6.78 1.32Y2.10 0.41Y0.70 1.04Y1.65
G0.001 G0.001 G0.001 G0.05
MVC indicates motor vehicle collision.
6.9% for middle, 4.0% for isolated lower, and 3.5% for isolated nasal fractures (P G 0.001). The results of univariate regression analysis for each pattern and other important predictors are listed in Table 3. Of note, sustaining a blunt facial fracture at an elderly age, as a pedestrian struck, or from a fall was all significantly associated with death (P G 0.001), whereas those sustaining facial fractures from blunt assault were less likely to die (P G 0.001). Although the racial and sex composition differed significantly between those who suffered a regional fracture pattern and those who suffered an isolated nasal fracture (Table 2) and appeared
Isolated Nasal, n = 986
Regional Pattern, n = 3554
P
38.2 73.4 68.1 25.8 6.2
38.8 78.3 59.8 32.2 8.0
G0.001 G0.001 G0.001 G0.001 0.054
TABLE 4. Multivariable Regression*
11.9 13.9
19.1 12.4
G0.001 G0.001
47.7 4.1 4.8 26.7 13.5 1.7
38.8 5.3 7.4 28.1 15.1 2.9
G0.001 0.115 G0.005 0.391 0.215 G0.05
Regional fracture pattern Isolated nasal, n = 986 Isolated upper, n = 117 Combined upper, n = 542 Panfacial, n = 69 Middle, n = 2308 Isolated lower, n = 518
*Significant. MVC indicates motor vehicle collision. Categorical variables compared by W2 test, continuous variables compared by 2-sided Student t test.
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Death
RR
95% Confidence Interval
P
Cumulative Incidence
Reference (control) group 4.06
V
V
3.5%
2.62Y6.30
G0.001
18.8%
3.46
2.43Y4.94
G0.001
16.8%
3.59 1.63 1.21
2.01Y6.40 1.18Y2.25 0.74Y1.99
G0.001 G0.005 0.448
17.4% 6.9% 4.0%
*Adjusted for age, mode of injury, and severity of other bodily injuries.
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
The Journal of Craniofacial Surgery
& Volume 24, Number 6, November 2013
associated with death on univariate analysis (Table 3), neither significantly predicted death after adjustment for age and mode of injury. Multivariable regression results for death are shown in Table 4. After adjustment, composite regional fracture patterns involving the upper face (isolated upper: relative risk [RR], 4.06; combined upper: RR, 3.46; panfacial: RR, 3.59; all at P G 0.001) or middle face (RR, 1.63; P G 0.005) were independently associated with death to varying degrees. Isolated lower face fractures were not significantly more associated with death than isolated nasal fractures (P = 0.448). In addition, there was a stepwise increase in risk for death with more superior facial involvement: isolated upper face fractures were 2.49-fold (P G 0.001), combined upper face fractures 2.12-fold (P G 0.001), and panfacial fractures were 2.20-fold (P G 0.005) more likely to die than middle face fractures. Of note, however, middle face fractures were not significantly different from lower face fracture on direct pairwise comparison (RR, 1.06; 95% confidence interval, 0.67Y1.70; P = 0.796).
Occult Intracranial Injury In total, 2103 blunt-mechanism facial fracture patients (46.4%) were considered at low risk for intracranial injury by the evaluated Canadian CT Head Rule criteria. Of these, 171 (8.1%) still suffered underlying intracranial injury. The cumulative incidence of intracranial injury despite being at ‘‘low risk’’ was 33.3%, 24.2%, and 22.0% for panfacial, combined upper, and isolated upper face fractures, respectively; in contrast, the cumulative incidence of intracranial injury among middle and isolated lower face fractures was 7.5% and 3.6%, respectively (df = 5, P G 0.001). Adjusted analysis revealed that, in patients who were otherwise at low risk for head injury, fracture patterns involving the upper face were significantly more associated with occult intracranial injury (Table 5). Specifically, there was a 4.12-fold (P G 0.001), 4.55-fold (P G 0.001), and 6.26-fold (P G 0.001) increased risk of sustaining an underlying intracranial injury with isolated upper, combined upper, or panfacial fractures, respectively. Although neither middle nor lower face fractures were significantly associated with intracranial injury (P = 0.097 and P = 0.254, respectively) when compared with isolated nasal fractures, there were still some important differences between these groups. The cumulative rates of intracranial injury after middle face and isolated nasal fractures were 7.5% and 5.3%, respectively, compared with 3.6% after lower face fracture. In a direct, adjusted pairwise comparison between middle face fracture and lower face fracture,
TABLE 5. Stratified Regression*: ‘‘Low Risk’’ on Canadian CT Head Rule* Occult Intracranial Injury
RR Regional fracture pattern Isolated nasal, n = 563 Reference (control) group Isolated upper, n = 41 4.12 Combined upper, 4.55 n = 161 Panfacial, n = 15 6.26 Middle, n = 1022 1.41 Isolated lower, n = 306 0.67
95% Confidence Interval
V
P
V
Incidence
5.3%
2.10Y8.08 2.92Y7.08
G0.001 G0.001
22.0% 24.2%
2.82Y13.87 0.94Y2.13 0.34Y1.33
G0.001 0.097 0.254
33.3% 7.5% 3.6%
*Confounding accounted for by stratification on available Canadian CT Head Rule criteria: aged 16 to 64 years, GCS score of 15, without basilar fracture, without a highrisk mechanism of injury (pedestrian struck or fall from elevation).
Death After Blunt Facial Fracture
middle face fractures were 2.10-fold more likely to have occult intracranial injury (P G 0.05) than lower face fractures.
DISCUSSION The purpose of this study was to evaluate the strength of the associations of various complex facial fracture patterns with mortality and occult intracranial injury. Clinical experience and several studies2,3,11,16 have suggested that rates of death and intracranial injury may vary by regional involvement and fracture pattern. We hypothesized that superiorly located facial fracture patterns would be more likely to die during hospitalization. The specific aim of the present study was to measure the association between several regional facial fracture patterns and death. In addition, to improve the clinical utility of our findings, we sought to investigate rates of intracranial injury by fracture pattern in those patients who may not otherwise be immediately suspected of having underlying or impending neurologic pathology. Although multiple studies have drawn attention to specific concomitant injuries with middle and lower face fractures,3,6,17 we found that facial fractures became strikingly associated with mortality and occult intracranial injury as more superior facial regions became involved. Specifically, compared with an isolated nasal fracture in similar patients, lower face fractures were not significantly associated with death, whereas sustaining a midface fracture was independently associated with a greater than 63% increased risk of death (P G 0.005); furthermore, all fracture patterns that involved the upper face were 3 to 4 times more likely to result in death during hospitalization. In the pairwise comparison of upper face fracture directly to middle face fracture, death was still more than twice as likely to occur if there was any involvement of the upper facial skeleton, indicating a stepwise increase in mortality with more superior facial involvement. Of the upper face fracture patterns, isolated upper face fracture had both the highest absolute risk and RR of death even after adjusting for important confounders. Although mortality rates between these upper face patterns did not significantly differ from one another, there is some evidence in this series that focused force delivery to the superior facial skeleton may be the most fatal. We further explored differences in rates of intracranial injury by fracture pattern as neurologic injury remains the most apparent mediator of death in craniofacial polytrauma patients. Because most institutions in the United States practice a low threshold for performing head computed tomography imaging in blunt facial trauma patients, to improve the clinical utility of our findings we limited our analysis to those who were fully alert and oriented and were otherwise at ‘‘low risk’’ for head injury by the available Canadian CT Head Rule criteria. We found that, even without alteration in alertness, and with a clinical picture that may not be immediately alarming for intracranial injury, those with trauma to the upper face were profoundly more likely to have occult intracranial injury. There was a direct correlation with proximity to the neurocranium and intracranial injury: occult intracranial injury occurred more often after upper face injury than middle and more often with middle face than lower. Taken together, these data support the need for careful imaging and monitoring for serious underlying or evolving neurologic insult in patients suspected of having injury to the superior facial skeleton, regardless of clinical picture at presentation. The average injury severity (ISS, 17.4), age (38.7 years), male predominance (77.3%), and mode of injury distribution in this series are consistent with previous reports,1,11,18 supporting the generalizability of our findings to other institutions. All fractures were confirmed by author review of craniofacial imaging to ensure accurate reporting of each fracture pattern.6,7,19 In addition, in contrast to the overwhelming majority of literature on this topic,
* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
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this article reports RRs that, unlike odds ratios, are directly translatable to actual-fold increases in risk. Finally, the large sample size in this series (ntotal = 4540, ndeath = 338, nintracranial injury = 1185) afforded us greater power at higher resolution to isolate the effect of individual pattern subgroups for specific outcomes while adjusting for the strongest confounders with multivariable modeling. Our finding that injury to the upper face was most strongly predictive of intracranial injury and death is consistent with previous investigations.2,11,20 In the past, this has been attributed to the combination of increased force required to fracture these areas and the effect of direct force transmission to the neurocranium.2,17,21 We have added to the existing literature by isolating the independent contribution that each regional fracture pattern has on morrtality while adjusting for the most important confounders in a multivariable model. Furthermore, we explored the ability of these fracture patterns to predict intracranial injury in the fully alert patient with a clinical picture that may not be immediately alarming for underlying or evolving intracranial injury. Understanding the relationship that specific facial fracture patterns have with intracranial injury in this group of patients may expedite identification of existing or impending intracranial insult. Our hope is to provide higher-resolution risk stratification to aid early identification of evolving injuries to supplement existing triage tools (eg, GCS score, Canadian CT Head Rule, etc) where they may fail to appropriately alert the provider. In addition, we have included our model specification, and statistics of interest including the RRs, SEs, the subgroup sample size for each facial fracture, and all estimates related to the confounders of the association with mortality. These types of estimates are essential for the future design of systematic reviews and meta-analyses with even more robust precision. We acknowledge some study limitations that should be considered when interpreting our results. This was a retrospective study using data extracted from a large, single institutional database that is reliant upon accurate data entry over a broad period of time. Furthermore, this study was undertaken at a high-volume urban trauma institute where regional referral patterns result in a patient population with more severe injuries than those that may be encountered in other centers. In our exploration of intracranial injury risk with minor head trauma, the resolution of the trauma registry and patient documentation did not allow us to confirm every criteria of the Canadian CT Head Rule. However, the most clinically apparent criteria were available and included.
CONCLUSIONS A thorough understanding of the increased morbidity and mortality conferred by specific patterns of craniofacial injury may improve early identification of the most critically ill patients and lead to greater efficiency in their management. In this series, we observed that mortality rates are directly related to proximity of the involved regional subunits to the neurocranium and quantified the independent contributions of these fractures. Furthermore, we found that even in the fully alert patient who is otherwise at low risk for head injury, any involvement of the upper facial skeleton is highly associated with underlying occult intracranial injury. These patients should be managed with heightened vigilance and followed closely during hospitalization with a low threshold for serial imaging, regardless of presenting clinical picture.
ACKNOWLEDGMENTS The authors thank J. Alex Kelamis, MD, and Michael R. Christy, MD, for their significant contributions to project conception and data collection.
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* 2013 Mutaz B. Habal, MD
Copyright © 2013 Mutaz B. Habal, MD. Unauthorized reproduction of this article is prohibited.
