Review of Orbital Fractures in an Urban Level I Trauma Center

Abstract

Objective: To perform a comprehensive review and analysis of surgically treated orbital fractures. Study Design: Retrospective cohort chart review study for surgically treated orbital fractures during 5 years. Results: A total of 173 patients (average age 41.6 years) were diagnosed with orbital fractures. Most were male with a ratio of 3.3:1. Most fractures were caused by assault (39.3%); 22.5% of the cases were bilateral. The left orbit (40.5%) was fractured more than the right. The orbital floor (97.1%) was the most common anatomic location and the maxilla (65.3%) was the most commonly involved bone. The average time from trauma to surgical intervention was 8.7 ± 14.6 days and the average time from surgical intervention to discharge was 5.1 ± 9.0 days. The transconjunctival incision (63%) was the most commonly used incision, and nonresorbable implant (92.7%) was the most commonly used implant. Finally, the length of stay for the repair of a simple orbital fracture was less than for complex orbital fracture (1.5 days and 5.9 days, respectively). Conclusion: Understanding the patterns and mechanisms of injury associated with orbital fractures can assist in developing standardized treatment protocols across all surgical specialties. This would ultimately allow for a uniform high quality of surgical care for patients with maxillofacial fractures.

Introduction

The incidence of adult orbital fractures in the United States is 10% to 25% among all facial fractures. However, literature addressing the epidemiology of orbital fracture in the United States is limited. Understanding fracture patterns and risk factors provides surgeons knowledge to appropriately diagnose and treat these fractures. Moreover, it can help guide implementation of systematic treatment algorithms. The objective of this study was to complete a comprehensive review and analysis of surgically treated orbital fractures at a nationally recognized level 1 trauma center.

Materials and Methods

This was a retrospective chart review of patients who sustained orbital fractures which were surgically repaired at Grady Memorial Hospital (GMH) between January 2012 and December 2016. This study was approved by Emory University School of Medicine Institutional Review Board and Grady’s Oversight Research Committee. Emory Medical Care Foundation database was used to identify patients using specific CPT billing codes associated with repair of orbital fractures (i.e., 21385, 21386, 21387, 21390, 21401, 21406, 21407, 21408). The study inclusion criteria were:

(1) patients diagnosed with an orbital floor fracture, (2) 18 years of age and older, and (3) treated at GMH by the craniomaxillofacial trauma team (i.e., Oral and Maxillofacial Surgery [OMFS], Otolaryngology [ENT], and/or Plastic and Reconstructive Surgery [PRS]). Exclusion criteria were patients younger than 18 years and patients who did not undergo surgical intervention. The predictor variables were: (1) demographics (i.e., age, gender, race), (2) injury details (i.e., mechanism of injury [assault; motor vehicle collision, MVC; gunshot wound, GSW; falls; sport related], laterality [right, left, or bilateral]), the anatomic location (orbital roof, floor, medial, or lateral orbital wall), pattern of orbital fracture (i.e., simple or complex), (3) involvement of other facial fractures (maxilla, mandible, nasal bone, zygomaticomaxillary complex (ZMC), naso-orbito-ethmoid (NOE), frontal sinus, temporal bone fractures), (4) treatment variables (i.e., time between trauma to surgical intervention, time from treatment to discharge, type of incision, type of reconstruction material, length of stay [LOS]). Patients were deidentified prior to data analysis.

Statistical analysis with chi-square, Mann-Whitney U test, and Kruskal-Wallis test was performed. Analyses were performed with SPSS (SPSS Inc), and P < .05 was considered statistically significant.

Results

A total of 173 patients met inclusion criteria (

Table 1. Summary of Demographic Variables.

Abbreviation: SD, standard deviation.

). There were 133 males (76.9%) with a male to female ratio of 3.3:1. The mean age was 41.6 years (range: 89-20 years). The most prevalent age-group was the fourth decade (30-39 years) compromising 31.2% of patients (

Table 2. Age Distribution of Patients.

). The agegroup younger than 39 years was more affected than the older population as the prevalence of orbital fractures decreased with each decade of age. The difference of age between males and females was not statistically significant (P value = .066). The racial distribution was African American (n = 110, 63.6%), Caucasian (n = 51, 29.5%), Hispanic (n = 8, 4.6%), and Asian (n = 4, 2.3%;

Table 3. Distribution by Race.

).

Mechanism of injury was found to be assault in 39.3% (n = 68), MVC in 31.2% (n = 54), falls in 10.9% (n = 19), GSW in 6.4% (n = 11), sport related in 3.2% (n = 6), and the mechanism of injury was not documented in 6.9% (n = 12;

Table 4. Mechanism of Injury of Orbital Fracture by Age-Group.

Abbreviation: MVC, motor vehicle collision.

and

Table 5. Mechanism of Injury of Orbital Fracture by Race.

Abbreviation: MVC, motor vehicle collision.

).

From all 173 patients, unilateral orbital fractures (n = 134, 77.5%) were more common than bilateral orbital fractures (n = 39, 22.5%). The left orbit was fractured in 40.5% (n = 70) of the cases in unilateral and bilateral cases (n = 173), while the right orbit was fractured in 37% (n = 64) of the cases in bilateral and unilateral cases.

In regard to anatomic location of fractures, our numbers reflect simple and complex orbital fractures, the sum of fractures per anatomical location may not add up to the total number of orbital fracture (n = 173) due to the involvement of more than one wall in complex orbital fracture. The most commonly involved anatomic location was orbital floor (n = 168, 97.1%), medial wall (n = 76, 43.9%), lateral wall (n = 70, 40.5%), or orbital roof (n = 28, 16.2%). Regarding patterns of orbital fracture, complex orbital fracture (n = 124, 71.7%) were more common than simple orbital wall fracture (n = 49, 28.3%). Regarding involvement of other facial fractures, we found the following: The most commonly involved bones were maxilla (n = 113, 65.3%), ZMC (n = 72, 41.6%), nasal bone (n = 75, 43.4%), NOE (n = 40, 23.1%), frontal sinus (n = 33, 19.1%), mandible (n = 28, 16.2%), and/or temporal bone (n = 12, 6.9%). Approximately 5.2% of patients had panfacial fractures (n = 9).

According to GMH trauma protocol, all patients were admitted to the trauma service and the craniomaxillofacial trauma team was consulted as needed. The average time from trauma to surgical intervention was 8.7 ± 14.6 days (range: 0-142 days). The average time from treatment to discharge was 5.1 ± 9.0 days (range: 0-67 days). The most commonly used incision was transconjunctival incision (n = 109, 63%). Others were subtarsal incision (n = 25, 14.5%), transconjunctival with cantholysis (n = 19, 11.0%), using an existing scar to access the fracture (n = 17, 9.8%), and subciliary incision (n = 3, 1.7%). Oral and Maxillofacial Surgery team used subtarsal incision (n = 19) and transconjunctival incision (n = 19) equally, PRS used transconjunctival incision (n = 55), and ENT used transconjunctival incision (n = 32).

Regarding reconstruction materials, 2 types of implants were used: (1) nonresorbable (eg, titanium mesh, Medpor, and Medpor Titan) and (2) resorbable implants (Synthes). The majority of orbits were reconstructed using nonresorbable implants (n = 107, 92.7%). Resorbable implants was used in 1.7% (n = 3), 3.5% (n = 6) of the cases did not require reconstruction, and the documentation was not mentioned in 1.7% (n = 3) of cases. Oral and Maxillofacial Surgery and ENT used preformed titanium mesh implants (n = 47 and 23, respectively), and PRS used Medpor Titan implant (n = 40). The average postoperative LOS for simple orbital fractures was 1.5 day (range 0-8 days) and for complex orbital fractures 5.9 days (range 0-67 days). Postoperatively, 19% of patients required intensive care unit admission (n = 33), secondary to reasons other than orbital fracture repair (i.e., polytrauma, head injuries, and/or orthopedic injuries).

Discussion

The purpose of this study was to complete a comprehensive review and analysis of surgically treated orbital fractures at a nationally recognized level 1 trauma center. This study represents one of the largest statistical samples regarding orbital fractures in a major US trauma center. The authors reviewed characteristics of orbital fractures at GMH database (medical records, documentations of physical examination, operative notes, and radiographic interpretations directly). The study focused on the following: (1) demographics (i.e., age, gender, race), (2) injury details (i.e., mechanism of injury [assault, MVC, GSW, falls], laterality [right, left, or bilateral]), the anatomic location (orbital roof, floor, medial, or lateral orbital wall), pattern of orbital fracture (i.e., simple or complex), (3) involvement of other facial fractures (maxilla, mandible, nasal bone, ZMC, NOE, frontal sinus, temporal bone fractures), (4) treatment variables (i.e., time between consult to surgical intervention, time from treatment to discharge, type of incision, type of reconstruction material, LOS).

Our study showed that males in their fourth decade are the most common patients. Our male to female ratio was 3.3:1 which was comparable to previous studies reporting ratios of 2.3:1 in United States, [1] 2.5:1 in Taiwan [2], and 3.6:1 in Germany. [3] The most common racial group for orbital fractures were African Americans (63.6%). In contrast, Chiang et al. conducted a similar review in Chicago, Illinois, and found that more Caucasians (56%) than African Americans (23%) had orbital fractures. [2] This is likely a result of population patterns in Atlanta and at GMH.

The most common mechanism of injury of orbital fractures at GMH was assault, which is consistent with other studies from major urban trauma centers in the United States. [1,2,4] The urban setting and GMH’s status as a level 1 trauma center are plausible explanations. Some other centers report MVCs are the most common etiology to orbital fractures. [5,6] Assaults were primarily found in younger patients (<70 years), followed by MVCs. Falls were a substantial cause of orbital fractures in the elderly individuals (>70 years). The correlation between falls as a cause of injury and patient age is important to ascertain, as orbital fractures caused by falls correlated with an older average age as opposed to other etiologies (70 vs. 40 years). This was in accordance with the study by Chiang et al. in 2016. [2] Falls are considered as a low energy mechanism for facial fractures. Fall causes different patterns and less severe facial fractures. [7,8] Kim et al. found that lateral orbital wall was the most commonly involved bone in fall cases and elderly population (>65 years). [8]

For bilateral orbital fractures to occur, the mechanism of injury has to generate a sufficient external force that will strike both orbits at once or each orbit at different times. [9] In our study, unilateral orbital fracture is more common than bilateral orbital fractures. Overall, our study found no significant difference in orbital fractures when differentiating by side. This was in contrast to studies by Chiang et al. in 2016 [2] and Chi et al., [10] who found that left-sided orbital fractures were more common than right orbital fractures. The literature also reveals that individuals who are assaulted are much more likely to have left-sided fractures compared to those who had an orbital fracture by a different mechanism of injury. It is hypothesized that the increased probability of left-sided fractures resulting from assaults can be attributed to the higher prevalence of righthandedness in the general population.

The pyramidal shaped orbit has 4 walls (roof, floor, medial, and lateral walls). The orbital rim is thicker and stronger than orbital walls. Orbital floor and medial walls are the thinnest (<1 mm), thus they are more vulnerable to fracture. In the literature, orbital floor is the most commonly involved anatomic location, [1] which is consistent with our study. In our study, the most commonly involved wall was the orbital floor followed by medial wall, lateral wall then orbital roof.

Orbital fractures have 2 main patterns, simple and complex. In simple fracture patterns, only one region of the internal orbit is involved such as blow-out fractures which involves either the orbital floor or medial wall. [11] Simple orbital fractures which involve not only orbital walls but also the rim and the adjacent bones such as the frontal, maxillary, and ZMC are known as complex orbital fractures. [12] Our study found that complex orbital fractures were more common than isolated orbital fracture. This could be due to the nature of referral patterns as more complex trauma cases are typically transferred to GMH for management. Patients who have an isolated orbital fracture may be treated in the community.

Of the orbital fractures seen, majority (n = 139, 80%) involved additional facial fractures and the remainder were isolated orbital bone fractures. In the literature, nasal bone fractures most commonly occur with orbital bone fractures. [1] However, our data show that maxillary bone fractures (i.e., Le Fort fractures) are the most commonly involved, followed by nasal bone fractures.

The average time interval between trauma to surgical intervention was 8.72 ± 14.62 days (0-142 days). Postoperatively, patients were discharged within 5.10 ± 9.035 days (0-67 days). This is consistent with the study by Damgaard et al., which demonstrated that orbital fracture repair within 14 days is associated with less postoperative complications. [13] In our center, the protocol for orbital trauma indicates treatment within 7 to 10 days after injury, after the edema has resolved. The operation takes place in an ambulatory setting unless the patient has another indication for admission.

The goal of surgical intervention is to prevent functional (eg, primary or reading gaze diplopia, and ocular motility dysfunction) or cosmetic problems (eg, enophthalmos). [14] Not every orbital fracture requires surgical intervention because many fractures do not lead to functional or cosmetic problems. [14] The decision to observe a fracture or proceed with surgical intervention is based on the clinical and radiographic evaluations. Immediate surgical intervention (within 24 hours) is indicated for oculocardiac reflex [15] or muscle entrapment. [16] Surgical intervention is indicated for (1) fractures more than 50% of floor dimension (1 cm²), [17] (2) enophthalmos (0.2 mm), [17] (3) persistent diplopia in primary or reading position, [17] and/or (4) clinical finding of ocular motility dysfunction without entrapped muscle. [17,18] Most orbital fractures can be managed by surgical intervention within 2 weeks, if indicated. [14]

Type of incision is crucial in orbital surgery. Transconjunctival incision was the most frequently used incision in our center. Transconjunctival incision is gaining popularity because it is more cosmetically pleasing with a hidden scar; it provides adequate access to reconstruct the orbital floor, inferior orbital rim, and/or medial orbital wall; and has less risk of eyelid retraction (scleral show and ectropion). Studies reported the incidence of ectropion with transconjunctival incision as low as 2.5% to 3%, [3,19,20] and the risk of entropion is 1.0%. [20]

The choice of the reconstruction material been always left to the surgeon’s discretion. Autogenous bone graft and synthetic implants (nonresorbable and resorbable) have been extensively discussed in the literature for orbital reconstruction. In our study, titanium mesh implants and porous polyethylene/titanium hybrid implants (Stryker Medpor Titan) are the most commonly used materials. Oral and Maxillofacial Surgery and ENT predominantly used the preformed titanium mesh implants while PRS used Medpor Titan. Both implants are highly recommended in the literature and are the most commonly used implants. [21] Titanium mesh implants are highly biocompatible, cost effective, easy to contour and stabilize, and are suitable to reconstruct large orbital defect because of their ability to maintain its shape and hold the orbital soft tissue. [21,22] It is available in a preformed form with 2 different sizes (small and large). Ellis et al. [23] showed the superior results of titanium mesh implants over autogenous bone. Medpor Titan implant is a sheet of titanium mesh embedded in porous polyethylene. It has all the advantages of the titanium plus the fibrous ingrowth of the polyethylene. [24]

In our study, longer LOS are correlated with complex orbital fractures that are associated with polytrauma. Those patients usually suffer from other comorbidities that require a longer LOS, such as extremity fractures or severe head injuries.

During the last 3 years, OMFS service at GMH implemented the use of patient-specific technologies (i.e., intraoperative computed tomography scans, 3D printing, and intraoperative navigation). These technologies have been shown to improve the quality of repair, [25] decrease reoperation rate, [25,26] decrease operative time, and overall LOS. Investigating details of these variables are a part of an ongoing, separate project.

There were few limitations to our study. Since this was a retrospective chart review, we can only show correlations and prevalence. We did not include unrepaired orbital fractures (i.e., if patient died prior to surgical intervention and/or orbital fractures who did not require surgical intervention). This may affect the overall incidence of orbital fractures in the general trauma population admitted to GMH. Lastly, our project specifically does not report complications. The 3 services involved in providing craniomaxillofacial surgery care are extremely collaborative. We preferred to minimize comparisons between the 3 services. There is no definitive protocol for orbital fracture management among the 3 specialties. However, there is general consensus between OMFS, ENT, and PRS, the main disagreement is regarding the following: (1) approach (i.e., transconjunctival vs. subciliary approach), (2) implant vendor (KLS, Stryker, etc), (3) type of implant, that is, titanium mesh, Medpor, Medpor Titan, and resorbable material. In conclusion, this study presents information regarding orbital fractures in a level 1 trauma center. Our sample reflects one of the largest modern, population-based studies of orbital fractures in the United States. Understanding the patterns and mechanisms of injury associated with orbital fractures can assist in developing standardized treatment protocols across all surgical specialties. This would ultimately allow for uniform high quality of surgical care for patients with maxillofacial fractures.