Complications and Reoperations in Mandibular Angle Fractures

Key Points

Question

Is there a difference in complications and reoperation rates between transcervical and transoral approaches to mandibular angle fracture repair?

Findings

In this cohort study of 135 patients with noncomminuted mandibular angle fractures, the transcervical approach resulted in a 17.2% major complication rate and a 14.9% reoperation rate, and the transoral approach resulted in a 18.8% major complication rate and 16.7% reoperation rate; differences between these approaches were nonsignificant.

Meaning

For noncomminuted mandibular angle fractures, the choice of either the transcervical or transoral approach does not affect surgical outcomes or predispose to reoperation.

Abstract

Importance

Mandible angle fractures can be repaired in a variety of ways, with no consensus on the outcomes of complications and reoperation rates.

Objectives

To analyze patient, injury, and surgical factors, including approach to the angle and plating technique, associated with postoperative complications, as well as the rate of reoperation with regard to mandible angle fractures.

Design, Setting, and Participants

Retrospective cohort study analyzing the surgical outcomes of patients with mandible angle fractures between January 1, 2000, and December 31, 2015, who underwent open reduction and internal fixation. Patients were eligible if they were aged 18 years or older, had 3 or less mandible fractures with 1 involving the mandibular angle, and had adequate follow-up data. Patients with comminuted angle fractures, bilateral angle fractures, and multiple surgical approaches were excluded. A total of 135 patients were included in the study. All procedures were conducted at a single, large academic hospital located in an urban setting.

Main Outcomes and Measures

Major complications and reoperation rates. Major complications included in this study were nonunion, malunion, severe malocclusion, severe infection, and exposed hardware.

Results

Of 135 patients 113 (83.7%) were men; median age was 29 years (range, 18-82 years). Eighty-seven patients (64.4%) underwent the transcervical approach and 48 patients (35.6%) received the transoral approach. Fifteen (17.2%) patients in the transcervical group and 9 (18.8%) patients in the transoral group experienced major complications (difference, 1%; 95% CI, −8% to 10%). Thirteen (14.9%) patients in the transcervical group and 8 (16.7%) patients in the transoral group underwent reoperations (difference, 2%; 95% CI, −13% to 17%). Active smoking had a significant effect on the rate of major complications (odds ratio, 4.04; 95% CI, 1.07 to 15.34; P = .04).

Conclusions and Relevance

During repair of noncomminuted mandibular angle fractures, both of the commonly used approaches—transcervical and transoral—can be used during treatment with equal rates of complication and risk of reoperation. For a patient undergoing surgery for mandibular angle fracture, smoking status is more likely to predict surgical outcomes rather than how the surgeon chooses to approach and fixate the fracture.

Level of Evidence

3.

This cohort study compares the use of transcervical and transoral techniques to repair mandible fractures in patients.

Introduction

During injury to the craniomaxillofacial skeleton, the mandible bone is commonly fractured. Mandibular fractures represent two-thirds of all craniomaxillofacial fractures, and the angle of the mandible is involved approximately one-third of the time.^1,2 A unique set of anatomic factors, including impacted wisdom teeth, competing biomechanical forces from muscle attachments, and the abrupt turn of the bone from the ramus to the body, all result in the angle being vulnerable to injury.³ Historically, the repair of these fractures has ranged from maxillomandibular fixation to external splinting techniques.

The advent of internal fixation plating has transformed the surgeon’s ability to uniformly and reliably treat mandible fractures following adequate reduction.^4,5,6 This process of osseous fixation can be performed with a single reconstruction plate, a fracture plate, 1 or 2 miniplates, lag screws, and a variety of unique monocortical plates, such as the Champy plate and railroad plate.^7,8,9 In addition to different plating techniques, the exposure of the angle fracture site can be done transcervically or transorally. Thus, the process of reducing and fixating angle fractures can involve a combination of surgical techniques. Although part of the surgical strategy can be dictated by the fracture characteristics, such as location and severity, the surgeon ultimately selects the combination of techniques that will most likely lead to osseous union and avoid complications. This selection process is important because repair of mandible fractures at the angle is associated with the highest rate of surgical complications.^10,11,12

Although there is exhaustive literature characterizing the factors associated with experiencing a surgical complication, little research is available to guide clinicians on the outcomes of those complications. When major complications, such as nonunion, are encountered, the standard of care involves performing more than 1 operation to manipulate the fracture to achieve better fixation and occlusion. To our knowledge, no study has specifically analyzed mandible angle fracture complications and the associated factors leading to reoperation. Our goal is to analyze patient, injury, and surgical factors, including approach to the angle and plating technique, associated with postoperative complications. In addition, we aim to determine whether any factors are associated with an increased risk of reoperation.

Methods

Medical Record Review

During a 15-year period between January 1, 2000, and December 31, 2015, medical records of all patients undergoing surgical treatment for mandible fractures at Barnes-Jewish Hospital in St Louis were retrospectively reviewed. All patients received operative treatment by surgeons from 2 different departments: otolaryngology–head & neck surgery and oral & maxillofacial surgery. To be included in the study, patients had to be aged 18 years or older and to have had at least 1 mandible fracture involving the angle. Patients with more than 3 mandible fractures and comminuted angle fractures were excluded. The degree of comminution was determined by reading the operative report. Inpatient and outpatient medical records were reviewed and all relevant information was transferred to a data collection form. The study was approved by Washington University School of Medicine in St Louis Institutional Review Board, with waiver of consent.

Variables reviewed included sex, age, comorbidities (27-item Adult Comorbidity Evaluation [ACE-27] scale¹³), smoking status, number of mandible fractures, presence of other facial fractures, severity of angle fracture, mechanism of injury, time to surgery, approach to the angle (transoral vs transcervical), plating details, operative time, perioperative antibiotics, postoperative complications, need for reoperation, time to reoperation, and length of follow-up. The transoral group included patients who received an intraoral approach to expose the angle fracture, with or without transbuccal application of hardware. The transcervical group included patients who received an external neck incision to expose the angle fracture and apply hardware. The severity of the angle fracture was classified as either nondisplaced to minimally displaced or moderately to severely displaced based on the surgeon’s description of the fracture in the operative note. We classified plating technique into 2 categories: fixation of the lower border of the angle fracture with a bicortical plate, including a reconstruction bar or fracture plate with tension band, and all other techniques. Complications were classified as minor if they required conservative treatment only and included infections resolved by oral antibiotics, prolonged wound healing, mild trismus, and minor malocclusion referred to dentistry. Complications were classified as major if they necessitated reoperation for resolution and included nonunion, malunion, severe malocclusion, exposed hardware, and severe infections. All patients receiving revision surgeries were classified as having a major complication. Only complications related to the angle fracture and surgical site were included.

Statistical Analysis

Univariate analysis was first performed with a χ² test or Fisher exact test for categorical variables and an unpaired, 2-tailed t test or Mann-Whitney test for continuous data, depending on normality. Following univariate analysis, multivariate analysis was performed for variables reaching statistical significance, set at P < .05, in univariate analysis and for variables thought to be of key clinical importance. Data were analyzed using SPSS software, version 22 (IBM Analytics).

Results

Between 2000 and 2015, there were 487 patients with mandible fractures receiving surgical treatment. Of these, 167 patients had mandibular angle fractures fulfilling the inclusion criteria. The following patients were excluded: 19 with no follow-up data, 9 treated with maxillomandibular fixation only, 3 with transoral approaches converted to transcervical, and 1 with bilateral angle fractures. This resulted in a total of 135 patients (113 men and 22 women) included in the study; median age was 29 years (range, 18-82 years). Most patients had an ACE-27 index level of 0 to 1 severity (81.3%) and were active smokers (64.1%). The most common mechanism of injury was assault (71.9%). Most patients had 2 or more mandible fractures (65.2%), with the angle fracture being nondisplaced or minimally displaced (65.9%). Most patients (80.7%) received a bicortical plate at the lower border of the angle. The median time to surgery was 6 days (range, 1-44 days). Eighty-seven (64.4%) of the 135 patients had their fractures approached transcervically; they were more likely to have moderate or severely displaced fractures and more likely to receive a bicortical plate at the lower border of the angle. Forty-eight (35.6%) patients received transoral treatment and experienced a faster median operating time of 92 minutes compared with 131 minutes for transcervical treatment (difference, 39 minutes; 95% CI, 4-74 minutes) (Table 1).

Table 1. Demographic Characteristics of Patients Undergoing Transcervical vs Transoral Approach to the Mandibular Angle.

Characteristic	No. (%)				P Value
	All (N = 135)	Transcervical (n = 87)	Transoral (n = 48)	Difference (95% CI), %
Sex
Male	113 (83.7)	75 (86.2)	38 (79.2)	7 (−6 to 20)	.29
Female	22 (16.3)	12 (13.8)	10 (20.8)
Age, median (range), y	29 (18 to 82)	30 (18 to 79)	29 (18 to 82)	1 (−4 to 6)	.70
ACE-27a
0-1	91 (81.3)	51 (77.3)	40 (87.0)	10 (−5 to 23)	.16
2-3	21 (18.7)	15 (22.7)	6 (13.0)
Smokingb
Never/former	37 (35.9)	19 (32.8)	18 (40.0)	7 (−11 to 25)	.44
Current	66 (64.1)	39 (67.2)	27 (60.0)
Other mandible fractures	88 (65.2)	59 (67.8)	29 (60.4)	8 (−8 to 24)	.33
Other facial fractures	21 (15.6)	13 (14.9)	8 (16.7)	2 (−13 to 17)	.80
Angle fracture severity
Nondisplaced or minimally displaced	89 (65.9)	51 (58.6)	38 (79.2)	20 (4 to 36)	.01
Moderately or severely displaced	46 (34.1)	36 (41.4)	10 (20.8)
Mechanism of injury
Assault	97 (71.9)	66 (75.9)	31 (64.6)	11 (−5 to 27)	.18
Other	38 (28.1)	21 (24.1)	17 (35.4)
Angle plating
FT/RB	109 (80.7)	77 (88.5)	32 (66.7)	22 (1 to 43)	.04
Other	26 (19.3)	10 (11.5)	16 (33.3)
Postoperative maxillomandibular fixation	27 (20.0)	21 (24.1)	6 (12.5)	11 (−2 to 24)	.10
Perioperative antibiotics
Ampicillin-sulbactam	29 (21.5)	16 (18.4)	13 (27.1)	9 (−6 to 24)	.24
Other	106 (78.5)	71 (81.6)	35 (72.9)
Time from injury to surgery, median (range), d	6 (1 to 44)	7 (1 to 44)	6 (1 to 27)	1 (−1 to 3)	.33
Operating time, median (range), minc	101 (64 to 255)	131 (81 to 255)	92 (64 to 183)	39 (4 to 74)	.03

Abbreviations: ACE-27, 27-item Adult Comorbidity Evaluation; FT/RB, fracture plate with tension band or reconstruction bar.

^aTwenty-three patients did not have ACE-27 data available.

^bThirty-two patients did not have smoking data available.

^cThese data only included patients with an isolated angle fracture with no other facial fractures.

In the 135 patients, there were 24 (17.8%) major complications and 12 (8.9%) minor complications. The most common major complication was severe infection requiring reoperation (10 [7.4%] patients), and the most common minor complication was mild malocclusion (5 [3.7%] patients). For patients who received transcervical treatment of the angle fracture, 15 (17.2%) had a major complication and 5 (5.7%) had a minor complication. In comparison, patients receiving transoral treatment developed 9 (18.8%) major complications and 7 (14.6%) minor complications. There was no statistically significant difference in complication rates between the 2 approaches (Table 2).

Table 2. Outcomes: Transcervical and Transoral Approach to the Angle Fracture.

Outcome	No. (%)			Difference (95% CI), %	P Value
	All (n = 135)	Transcervical (n = 87)	Transoral (n = 48)
Complications
Minor	12 (8.9)	5 (5.7)	7 (14.6)	9 (−1 to 19)	.08
Major	24 (17.8)	15 (17.2)	9 (18.8)	2 (−11 to 16)	.77
Reoperations	21 (15.6)	13 (14.9)	8 (16.7)	2 (−13 to 17)	.80

A total of 21 patients (15.6%) underwent reoperations, and 5 (23.8%) of these patients went on to have further revision surgeries, with 1 patient having a total of 4 reoperations. The reasons for reoperation were severe infection in 11 (52.4%) patients and malunion or nonunion in 10 (47.6%) patients. Removal of hardware was performed in 14 (66.7%) reoperations. The median time after the original operation was 8 weeks. For the 87 patients undergoing transcervical treatment, 13 (14.9%) underwent reoperations. For the 48 patients undergoing transoral treatment, 8 (16.7%) underwent reoperations. There was no significant difference in the rate of reoperations between the transcervical and transoral treatment groups (Table 2).

Univariate analysis was performed for all variables (Table 3). None of the variables analyzed had a statistically significant effect on the outcome of major complications and rate of reoperations. Active smoking was the only variable that approached statistical significance. For this reason, it was included in the multivariate analysis, along with approach to the angle and plating technique (Table 4). Of these 3 variables, only active smoking had a significant effect on the rate of major complications (odds ratio, 4.04; 95% CI, 1.07-15.34; P = .04), and none of these 3 factors had a significant effect on the rate of reoperations.

Table 3. Univariate Analysis for Major Complications and Reoperations^a.

Characteristic	Major Complication, OR (95% CI)	P Value
Sex (male vs female)	0.97 (0.30-3.17)	.96
Age (≥30 vs <30 y)	1.25 (0.52-3.02)	.62
Comorbidity (moderate/severe vs mild/none)	1.47 (0.47-4.58)	.51
Smoking (current vs never/former)	3.63 (0.98-13.41)	.05
Mandible fractures (1 vs ≥2)	1.15 (0.46-2.88)	.76
Other facial fractures (present vs absent)	0.74 (0.20-2.74)	.65
Angle fracture severity (moderately/severely displaced vs minimally/nondisplaced)	0.96 (0.38-2.45)	.93
Mechanism of injury (assault vs other)	0.59 (0.23-1.49)	.27
Approach to angle fracture (transcervical vs transoral)	0.90 (0.36-2.25)	.83
Plating technique (FT/RB vs other)	3.03 (0.67-13.83)	.15
Postoperative maxillomandibular fixation (yes vs no)	0.77 (0.24-2.46)	.65
Perioperative antibiotics (ampicillin-sulbactam vs other)	0.69 (0.22-2.20)	.53
Injury to surgery (≥6 vs <6 d)	0.78 (0.32-1.89)	.58

Abbreviations: FT/RB, fracture plate with tension band or reconstruction bar; OR, odds ratio.

^aUnivariate analysis was performed for all demographic variables listed in Table 1. The only variable approaching statistical significance was smoking status.

Table 4. Multivariate Analysis for Major Complications and Reoperations.

Characteristic	Major Complication, OR (95% CI)	P Value	Reoperation, OR (95% CI)	P Value
Smoking (current vs never/former)	4.04 (1.07-15.34)	.04	1.87 (0.66-5.30)	.24
Approach to angle fracture (transcervical vs transoral)	0.61 (0.21-1.77)	.72	1.46 (0.55-3.89)	.45
Plating technique (FT/RB vs other)	3.75 (0.76-18.59)	.15	2.03 (0.759-5.43)	.16

Abbreviations: FT/RB, fracture plate with tension band or reconstruction bar; OR, odds ratio.

Discussion

Surgical treatment of mandibular angle fractures can be technically challenging. The exposure can be difficult, the view can be limited, and repair can be performed with a variety of approaches and plating techniques. One point of debate is surgical approach to the angle fracture. Transcervical approach has the advantage of complete visual exposure of the fracture line and allowing direct control of the fracture segments. However, this approach carries a risk of injury to the marginal mandibular nerve as well as leaving a visible scar. In contrast, the transoral approach is able to avoid these risks through an intraoral incision while providing the surgeon with direct visualization of occlusion during application of bone plates. However, it may be difficult to adapt plating and manipulate fracture segments through an intraoral incision.^14,15,16 Once the fracture is exposed, there are further variations of plating techniques to fixate the fracture. The decisions regarding approach and plating are often dictated by fracture orientation, number of fracture segments, type of fracture, and amount of displacement. In this study, we have attempted to reduce the angle fracture variables as much as possible by including only noncomminuted, bicortical, and unilateral single fractures isolated at the angle.

The overall rate of major complications from 135 patients in our study was 17.2%, which is within the range of 0% to 32% documented in other well-established studies.^{6,8,17,18,19,20} Both the rate of minor complications and major complications was higher for the transoral group compared with the transcervical group, although neither of these outcomes reached statistical significance. This finding is in agreement with Toma et al,²¹ who found no difference in complications between the transoral and transcervical approach in 78 patients with angle, body, and ramus fractures. In addition, our study analyzed the rate of reoperations, which is a reflection of the clinical end point of major complications, such as nonunion. Our overall rate of reoperations was 15.6% compared with as high as 27% reported in the literature.²² In a retrospective review of 103 mandible fractures, Luz et al²³ found no difference in reoperation rates between transcervical and transoral approaches to mandible fractures at all sites. This study included only 22 angle fractures, and most of the reoperations were performed for body fractures. The mandibular angle is a unique anatomic location and the principles of repairing fractures at this site are distinctly different compared with repair of body, condylar, and parasymphysis fractures. The mandibular angle is the site where both the transcervical and transoral approaches are most readily used, making it the mostly clinically important site to compare approach outcomes. Moreover, Luz et al²³ included comminuted fractures, which are more complicated to fixate and may be predisposed to reoperation. In our study, which exclusively analyzed noncomminuted angle fractures, the rate of reoperations in the transcervical and transoral groups was 14.9% and 16.7%, respectively, and this difference was not significant. Furthermore, our multivariate analysis comparing these 2 approaches resulted in no significant difference in major complications or rate of reoperations. One of the significant differences between the 2 approaches based on our analysis was operating time, which was 39 minutes shorter for the transoral approach. This difference can be attributed to the extra time required to dissect through soft tissue and preserve vessels and branches of the facial nerve when approaching fractures transcervically. Comparatively, this difference is almost twice as long when referenced to the 21- to 23.7-minute difference cited by other investigators.^15,21

Different plating techniques for mandible angle fractures have been compared in the literature with varied results.^1,12,22,24 Regev et al²² performed a meta-analysis showing lower reoperation rates with use of monocortical plates compared with bicortical plates, 1 plate compared with 2 plates, and noncompression plates compared with compression plates. We divided plating technique into 2 broad categories based on the treatment used: reconstruction bar or fracture plate at the lower border of the mandibular angle and all other monocortical techniques. Rather than classifying patients based on all of the physical differences of the plates they received, we chose this broad classification because it takes into account the surgeon’s clinical assessment of the fracture and the patient. For example, for fractures that are challenging or time consuming to reduce, the surgeon is less likely to fixate with only a single miniplate at the superior border, despite knowing that this physical plate is less likely to lead to complications.²² We believe that the much more important decision that the surgeon must face along the plating algorithm is whether to expose the inferior border of the fracture and apply a high-profile plate, which takes into account fracture characteristics prior to reduction. Furthermore, this classification of plating technique was made partly because of the demographics of our patient population, who are mostly uninsured, unreliable in follow-up, and more likely to engage in high-risk behaviors: 71.9% of our patients received their fractures from assault. For this group, surgical repair is aimed at definitive fixation without relying on maxillomandibular fixation and diet restrictions to promote fracture healing. Thus, we chose to compare the most rigid fixation techniques, where bicortical plates are applied to the lower border of the angle, with all other monocortical techniques, such as railroad plate, Champy plate, and 2 miniplates. In both the univariate and multivariate analyses, we found no significant difference in major complications or reoperation rates based on plating technique.

In our study, patients with moderate to severely displaced fractures had a higher likelihood of receiving a transcervical approach as well as a high-profile plate at the inferior border. It may be that surgeons are more likely to utilize the transcervical approach when anticipating difficult reduction, as this method exposes the fracture fragments more completely. Meanwhile, for nondisplaced to minimally displaced angle fractures, surgeons may be more likely to utilize the transoral approach to apply a miniplate at the superior border to save time. Of the 46 moderate to severely displaced fractures, 36 were approached transcervically and 10 were approached transorally. Within this more severely displaced group, the major complication rates for transcervical and transoral approaches were 17% and 20%, and the reoperation rates were 19% and 20%, respectively. These findings suggest that, despite greater exposure for reduction through a transcervical approach, even more severely displaced fractures can be safely fixated through an intraoral approach. In addition, our data suggest that, following reduction, monocortical plating techniques are equivalent to the most rigid plating techniques. Thus, even in a high-risk patient population, the degree of displacement for noncomminuted angle fractures should not rule out a transoral approach.

The only significant factor from our multivariate analysis was smoking. Those who were active smokers had higher rates of major complications compared with former smokers and patients who never smoked (P = .04). Thus, for a patient undergoing surgery for mandibular angle fracture, smoking status is more likely to predict surgical outcomes rather than how the surgeon chooses to approach and fixate the fracture.

Limitations

This study was limited by the fact that we were not able to report management of teeth, especially management of the third molar, as a variable because this information was not consistently documented in the operative notes. Furthermore, this study was limited by the fact that patients had varying follow-up times, and it is possible we did not capture all complications within our follow-up data. Better follow-up data are needed to capture long-term outcomes and complications, such as facial nerve paresis and sensation deficits. In addition, trauma patients engage in high-risk behavior and are known to be unreliable with postoperative instructions, which may predispose them to further complications. Finally, this was a retrospective review at a single institution with surgeon variability. This area of research is in need of randomized clinical trials or within-institution analyses that can control for surgeon and operating room variability.

Conclusions

During surgical repair of mandibular angle fractures, the choice of either the transcervical or transoral approach does not affect surgical outcomes or predispose to reoperation. Surgeon or patient preference may ultimately determine which approach should be used. If time is a concern, we advocate use of the transoral approach as it is significantly faster. Once the angle fracture is exposed and reduced, definitive fixation can be achieved without placing a high-profile plate at the lower border, and this does not affect surgical outcome or predispose to reoperation.