Figure. Methods of repairing angle of the mandible fractures. A, Location of fractures; B, lateral view of the fractures; C, fracture reduction with arch bars; D, percutaneous approach to plating; E, anterior view of percutaneous approach to plating; F, postreduction with arch bars and plates. Illustration by Scott A. Weldon, MA, CMI. Published with permission from Baylor College of Medicine.
Guy WM, Mohyuddin N, Burchhardt D, Olson KL, Eicher SA, Brissett AE. Repairing Angle of the Mandible Fractures With a Strut Plate. JAMA Otolaryngol Head Neck Surg. 2013;139(6):592-597. doi:10.1001/jamaoto.2013.3246
Author Affiliations: Bobby R. Alford Department of Otolaryngology–Head and Neck Surgery, Baylor College of Medicine, Houston, Texas.
Importance Despite multiple fixation techniques, the optimal method of repairing mandibular angle fractures remains controversial.
Objective To evaluate the outcomes when using a 3-dimensional, curved strut plate in repair of angle of the mandible fractures.
Design Retrospective cohort study.
Setting Level I trauma center at an academic institution in Harris County, Texas.
Participants Patients with diagnostic codes involving angle of the mandible fractures that were repaired by the otolaryngology–head and neck surgery service from February 1, 2006, through February 28, 2011.
Exposure Open reduction internal fixation using either a 3-dimensional curved strut plate or any other type of repair technique for angle of the mandible fractures.
Main Outcomes and Measures Complication rates, postoperative complaints, and operative characteristics.
Results Ninety patients underwent qualifying procedures during the study period. A total of 68 fractures (76%) were repaired using the 3-dimensional curved strut plate and 22 (24%) were repaired using other methods. The revision surgery rate was 10% for the strut plate group (7 patients) and 14% for the non–strut plate group (3 patients), with no significant differences in rates of infection (3 [4%] vs 2 [9%]), dehiscence (4 [6%] vs 2 [9%]), malunion (1 [1%] vs 2 [9%]), nonunion (3 [4%] vs 0), hardware failure (1 [1%] vs 1 [5%]), malocclusion (2 [3%] vs 2 [9%]), and injury to the inferior alveolar nerve (1 [1%] vs 1 [5%]). The most common postoperative complaints were pain (13 [19%] vs 6 [27%]), followed by numbness (5 [7%] vs 2 [9%]), trismus (4 [6%] vs 3 [14%]), edema (3 [4%] vs 3 [14%]), and bite deformity (2 [3%] vs 2 [9%]), with a mean (range) follow-up time of 54.7 (2-355) days for the strut plate group vs 46.8 (8-308) days for the non–strut plate group.
Conclusions and Relevance The 3-dimensional curved strut plate is an effective treatment modality for angle fractures, with comparable infection rates, low incidence of alveolar nerve injury, and trends for decreased length of operation, complications, and infections compared with other techniques.
Fractures of the mandible are a common facial injury in the United States. The most common cause is assault (53.7%), followed by motor vehicle crashes (28.1%), falls (7.1%), and sports-related injuries (2.1%). Male patients account for 84% of all mandible fractures, with the angle of the mandible being the most common location (27.6%).1
Multiple techniques exist for repairing mandibular angle fractures. Common fixation methods include the Champy technique, placement of a tension band superiorly with an inferior miniplate, placement of dual miniplates, placement of a locking screw plate on the inferior border, or placement of a 3-dimensional strut plate.2
Despite multiple fixation techniques, the optimal method of repairing mandibular angle fractures remains controversial. The 3-dimensional curved strut plate is a relatively new design compared with the other fixation techniques. The strut plate was designed to have a decreased risk to the inferior alveolar nerve and no need for plate contouring. It is low profile and uses a noncompressive, single plate with monocortical screws. The strut plate is suitable for both favorable and unfavorable fractures. Despite its seemingly widespread acceptance, there are few clinical studies that evaluate the clinical outcomes of the strut plate.
The purpose of this study was to evaluate our experience using the 3-dimensional curved strut plate to repair angle of the mandible fractures at a level I trauma center. The specific outcomes evaluated included complication rates and patient postoperative complaints. Complications were defined as anything that caused a fracture to require additional intervention following the original fixation. These included dehiscence, infection, nonunion, malunion, malocclusion, hardware failure, injury to the inferior alveolar nerve, and undiagnosed injuries. The postoperative complaints that were assessed included pain, trismus, bite deformity, persistent numbness, and edema.
A retrospective cohort study was undertaken at Ben Taub General Hospital, a level I trauma center in Harris County, Texas, which includes the greater Houston area. The institutional review boards at both Baylor College of Medicine and the Ben Taub General Hospital approved the research. Because of the retrospective nature of the study, informed consent was not necessary. The study spanned a 5-year period from February 1, 2006, to February 28, 2011. The medical records were selected on the basis of International Classification of Diseases, 9th Revision, Clinical Modification, diagnostic codes involving angle of the mandible fractures (802.20-802.39) that were repaired by the otolaryngology–head and neck surgery service. Only patients with fractures of the angle of the mandible were included; having multiple fractures was not an exclusionary criterion. Both the paper and electronic medical records were reviewed for demographic information, medical history including preoperative complaints and comorbidities, preoperative care, fracture characteristics as assessed by means of radiographic findings, type and duration of immobilization, surgical approach, operative details (length of operation and estimated blood loss), postoperative complications (dehiscence, infection, nonunion, malunion, malocclusion, hardware failure, injury to the inferior alveolar nerve, and undiagnosed injuries), and subjective complaints (pain, trismus, bite deformity, persistent numbness, and edema). All patients were evaluated postoperatively with either a maxillofacial computed tomographic scan or a panoramic radiograph. Postoperatively, all patients were prescribed a modified diet for 6 weeks, either a full liquid diet if they were discharged in mandibulomaxillary fixation (MMF) or a mechanical soft diet if they were not in MMF; chlorhexidine oral rinse; acetaminophen with codeine elixir; and 7 days of clindamycin. Patients were seen for initial follow-up 2 weeks after discharge.
A total of 232 patients with mandible fractures were evaluated for treatment by the otolaryngology–head and neck surgery service during the 5-year period. Of these 232 fractures, 104 (45%) involved at least 1 angle of the mandible, with 3 cases involving bilateral angle fractures (1.2%). Ninety of these patients underwent operative repair by the otolaryngology–head and neck surgery service. Among these 90 patients undergoing open reduction internal fixation, 68 fractures (76%) were repaired using the 3-dimensional curved strut plate and 22 (24%) were repaired using other methods, including the Champy technique (1 [5%]), superior tension band and inferior border plate (16 [73%]), reconstruction plate (3 [14%]), and placement only into MMF (2 [9%]). With regard to the strut plate and non–strut plate groups, the mean (range) age of participants was 28.3 (14-51) years and 27.9 (15-58) years, with a male predominance (94% and 91%), respectively. The most common mechanism of injury for the strut plate group was aggravated assault (84%), followed by fall (12%), motor vehicle crash (3%), and sports injury (1%). For the non–strut plate group, the most common mechanism of injury was also aggravated assault (77%), followed by motor vehicle crash (14%), fall (5%), and gunshot wound (5%). The mean (range) length of time from injury to operation for the strut plate and non–strut plate groups was 4.3 (0-14) days and 5.6 (1-37) days and from injury to presentation at the hospital was 1.5 (0-10) days and 3.1 (0-33) days, respectively. Preoperative complaints for the strut plate and non–strut plate groups included pain (84% vs 73%), bite deformity (68% vs 68%), edema (54% vs 59%), trismus (50% vs 50%), and numbness in the inferior alveolar nerve distribution (37% vs 27%). Fractures were classified as open in 19 patients (28%) vs 10 patients (45%) for the 2 groups. Alcohol was involved in 43% vs 45% and cocaine in 24% vs 27% of fractures. Midface fractures were present in 9% vs 23% of patients, and 1 patient in each group had injuries severe enough to warrant tracheotomy. Characteristics of the 2 groups were compared using a 2-proportion z -test, and there were no significant differences between the 2 groups. A 2-tailed t test was used to compare the length of time from injury to the hospital and to the operation, and no significant differences were found (Table 1).
The most common location for a fracture in the strut plate and non–strut plate groups was the left angle (57% vs 73%), followed by the right angle (49% vs 36%). The left parasymphysis (28% vs 14%) and right parasymphysis (22% vs 18%) were the next most common locations, respectively (Table 2). Bilateral angle fractures were present in 4% of patients in the strut plate group and 9% in the non–strut plate group. A 2-proportion z -test was used to compare the location of fractures, and there were no significant differences between the groups.
Preoperatively, all patients received prophylactic intravenous antibiotics (either alone or in combination), with 88 (98%) receiving clindamycin, 14 (16%) receiving ceftriaxone, and 8 (9%) receiving ciprofloxacin. Preoperative oral chlorhexidine gluconate was given to 87 patients (97%). All patients were restricted from receiving anything by mouth if surgery was immediately scheduled or restricted to a mechanical soft diet.
All patients receiving placement of the strut plate underwent a combined intraoral and percutaneous approach to identify and reduce the fracture site (Figure). The fractures that were not repaired with a strut plate were identified and reduced using various approaches, including percutaneously and intraoral, with 9% requiring an external approach. The majority of patients in the strut plate and non–strut plate groups were placed into rigid MMF with arch bars intraoperatively (78% vs 64%), with the remainder placed into 4-point fixation. Of the 68 patients in the strut plate group, 35 (51%) had the arch bars kept in place postoperatively, compared with 14 of the 22 patients (64%) in the non–strut plate group. The mean (range) length of time that patients remained in MMF was 17.3 (0-141) days vs 11.9 (0-42) days (P = .45), and the time in arch bars was 54.3 (0-242) days vs 36.0 (4-105) days (P = .10), respectively. The mean (range) duration of the operation was 219.5 (70-525) minutes vs 232.2 (77-369) minutes, with a mean (range) estimated blood loss of 83.0 (10-800) mL vs 85.9 (5-300) mL (Table 3). All patients were evaluated preoperatively with a maxillofacial computed tomographic scan. Postoperative reduction was evaluated for the strut plate and non–strut plate groups via panoramic radiograph 71% (48 patients) vs 36% (8 patients) of the time (P = .004), with maxillofacial computed tomography used to evaluate the remainder.
The revision surgery rate was 10% for the strut plate group (7 patients) and 14% for the non–strut plate group (3 patients). There were no significant differences between the 2 groups with respect to rates of infection (3 [4%] vs 2 [9%]), dehiscence (4 [6%] vs 2 [9%]), malunion (1 [1%] vs 2 [9%]), nonunion (3 [4%] vs 0), hardware failure (1 [1%] vs 1 [5%]), malocclusion (2 [3%] vs 2 [9%]), and injury to the inferior alveolar nerve (1 [1%] vs 1 [5%]), although trends for fewer complications in the strut plate group do exist (Table 4).
The most common postoperative complaint was pain (19% vs 27%), followed by numbness (7% vs 9%), trismus (6% vs 14%), edema (4% vs 14%), and bite deformity (3% vs 9%), with a mean (range) follow-up time of 54.7 (2-355) days for the strut plate group vs 46.8 (8-308) days for the non–strut plate group (Table 4). Of note, 11 patients in the strut plate group (16%) did not return to the clinic for follow-up, compared with 1 patient in the non–strut plate group (5%).
Various techniques have been described to repair fractures of the angle of the mandible. In 1978, Champy et al3 described using a single miniplate via an intraoral incision to adequately address the angle of the mandible fracture. Several studies have been performed to evaluate the multiple techniques, both on the biological level as well as with patient outcomes. Alkan et al4 compared mandibular angle fractures in sheep repaired using either the Champy technique, dual miniplates either in mono or biplanar placement, or a 3-dimensional strut plate. They showed the strut plate to be superior to either the Champy technique or monoplanar dual miniplates with regard to the mean compressive forces. Zix et al5 evaluated the use of the curved 3-dimensional strut plate on 20 consecutive patients and showed a mean operative time of 65 minutes with no infections or complications. With these studies in mind, the 3-dimensional curved strut plate has become an increasingly popular choice for repairing fractures involving the mandibular angle.
Infection rate following plating is an important outcome. Fox and Kellman6 showed an infection rate of 2.9% in patients treated with 2 miniplates; however, infection rates as high as 25%7 with 2 miniplates and as high as 15.8% using a single miniplate have been reported.8 A meta-analysis by Regev et al9 analyzing compression vs noncompression, monocortical vs bicortical screws, and 2 plates vs 1 showed lower infection rates with noncompression (20.7% vs 8.2%), monocortical screws (18.6% vs 7.8%), and single-plate fixation (20.4% vs 6.0%). Although their meta-analysis did not specifically assess strut plates given their lack of data in the literature, it did support the concepts used in the design of the strut plate (noncompression, monocortical screws, and single plate). When evaluating the strut plate, Bui et al10 performed a retrospective review that showed a comparably low infection rate (8.2%) when patients were treated with 1 week of postoperative antibiotics, increasing to 14% when a tooth was involved in the fracture site and not extracted but only 5.6% when the involved teeth were extracted. Guimond et al11 evaluated 37 patients treated with the Synthes curved strut plate and showed satisfactory reduction and occlusion in all cases with a 5.4% infection rate. The present study's infection rate of 4% using the strut plate is comparable to the aforementioned.
The 10% revision surgery rate in the strut plate group is slightly improved compared with the 12% revision surgery rate for the Champy technique.12 As for those patients undergoing revision surgery in the present study, 1 patient underwent a second operation on postoperative day 1 because the plate was splaying the fracture site open as a result of poor reduction and a second patient was noted to have malpositioning of the strut plate beyond the posterior border of the mandible. A third patient had to be placed back in MMF because of malocclusion, but the strut plate remained in place. Another patient had severe periodontal disease, and her plate removal occurred more than 1 year after her initial repair. One patient had developed purulent drainage from the incision site with extrusion of hardware. Of note, this patient had a tooth involved in the fracture line that was not extracted during the initial operation. One patient had failure of union found incidentally at an oral surgery follow-up appointment for extraction of a tooth that had been involved in the fracture site but not removed. This patient required an iliac bone graft with a 2.4-mm reconstruction plate. Another patient had developed purulent drainage from his wound with radiographic evidence showing that the strut plate screws were not in position. This patient had not followed the postoperative soft diet and required removal of hardware with replating using an iliac bone graft and a 2.4-mm reconstruction plate. A fourth patient had a tooth that remained in the fracture line and there was nonunion of the mandible that necessitated replating. Of the above patients who developed significant infections necessitating removal of hardware, 3 of 4 had a tooth in the fracture line that was not extracted during the initial operation.
The 4 patients in the strut plate group who presented to the clinic with evidence of dehiscence (6.1%) were treated conservatively and prescribed oral clindamycin and chlorhexidine gluconate oral rinse. None of these patients required additional surgical intervention. This dehiscence rate is comparable to those of other studies involving strut plates11 and improved compared with both the Champy technique and the dual miniplates technique, which have dehiscence rates of 11.1% and 7.4%, respectively.13
There was a 1.5% malunion rate in the strut plate group, compared with 9.1% in the non–strut plate group. The 1 patient in the strut plate group with malunion was referred to the oral and maxillofacial surgery (OMFS) service, where her case was managed conservatively. One of the patients in the non–strut plate group was evaluated by OMFS staff but after his panoramic radiograph was obtained was lost to follow-up. The second patient in the non–strut plate group with malunion was never evaluated by OMFS staff. The 1.5% malunion rate in the present study is comparable to the 0% malunion rate found by Fox and Kellman6 and the 1.4% malunion rate found by Ellis and Walker.7
The nonunion rate in the strut plate group was 4.4%, compared with 0% in the non–strut plate group. Although the difference was not statistically significant, this does represent a complication with a high rate of morbidity. Two of the patients required an external fixation performed by the OMFS service, with the third patient undergoing debridement of nonviable bone with removal of hardware and replating using a strut plate. Levy et al8 have shown a 5.2% nonunion rate when using the Champy technique, with other studies using 2 miniplates finding a 0% to 1% nonunion rate.6,7
With regard to operative technique, all patients required a percutaneous approach to access the angle of the mandible, which is a disadvantage when compared with the Champy technique, which leaves no external scars.14 Of 68 patients, 1 required a second percutaneous incision to access the inferior aspect of the mandible.
Of the patients placed into rigid MMF in the strut plate group who remained in fixation postoperatively (51%), the mean length of time in rigid fixation and arch bars was 17.3 and 54.3 days, respectively. However, 1 patient lived in another state and did not return to the clinic for follow-up until 141 days postoperatively, at which time her wires and arch bars were removed. Two other patients had been lost to follow-up and returned to the clinic 242 and 105 days postoperatively, at which time their arch bars were removed. If these patients were excluded because their length of time in arch bars was not part of their treatment plan, the mean length of time in rigid fixation and arch bars was 13.6 and 43.5 days, respectively. This is comparable to the non–strut plate group, in which the mean length of time in MMF and in arch bars was 11.9 (P = .45) and 36 (P = .43) days, respectively. Of note, the patient in the non–strut plate group who was in arch bars for 105 days had delayed healing and was therefore intentionally kept in arch bars for the extended time frame.
If the outliers are excluded, these lengths of time may still be considered high compared with those in other protocols and were believed to reflect the lack of reliability of this patient population in adherence to mechanical soft diets. It should also be noted that the patients in the strut plate group were in MMF for a longer period of time (13.6 vs 11.9 days) but this did not reach statistical significance (P = .045). A similar finding was present in the length of time that the patients remained in arch bars (42.1 vs 36 days; P = .55). Notwithstanding, these longer times may have favored the improved results with the strut plate, although only 51% of the strut plate group remained in MMF postoperatively, compared with 64% in the non–strut plate group.
To make the decision between MMF and 4-point fixation, patients whose mandible fractures were isolated, nondisplaced, and at a favorable angle were placed into 4-point fixation, and the remainder were placed into MMF. Although not a significant difference, there was a trend for shorter operative time in the patients whose fractures were repaired using the strut plate (mean duration, 219.5 vs 232.2 minutes).
There was a significant difference in the postoperative imaging performed between the 2 groups, with the strut plate group receiving a panoramic radiograph 71% of the time vs 36% in the non–strut plate group (P = .004), although studies have failed to show any benefit in any postoperative imaging in patients without physical examination findings or history providing evidence to support a postoperative complication.14,15
The most common complaint at follow-up visit in the strut plate group was pain (19%). Of the 5 patients (7%) who complained of persistent postoperative numbness, only 1 (1%) had new-onset postoperative numbness indicating likely injury to the inferior alveolar nerve, which was attributed to repair. This is comparable to the evaluation by Barry and Kearns12 of the Champy technique, which showed an 8% rate of postoperative numbness in the inferior alveolar nerve distribution. However, 11 patients (16%) never came to the clinic for postoperative clinical evaluation, including 4 patients who were discharged home with arch bars in MMF. Of note, 1 patient who presented with a mandibular angle fracture was still in arch bars from an operation he had undergone 1 year earlier, which is an important factor to consider when deciding whether to discharge patients home either in MMF or with arch bars. In a comparison between the strut plate and non–strut plate groups, although there were no significant differences with regard to both complications and complaints, trends for fewer complications and decreased postoperative complaints in the strut plate group were readily apparent (Table 4).
In conclusion, the 3-dimensional curved strut plate is an effective treatment modality for angle of the mandible fractures, with infection rates comparable to those found with other methods and low incidence of alveolar nerve injury, and trends for decreased duration of operation, complications, and infections.
Correspondence: Anthony E. Brissett, MD, Bobby R. Alford Department of Otolaryngology–Head and Neck Surgery, Baylor College of Medicine, 6500 Fannin St, Ste 1701, Houston, TX 77030 (firstname.lastname@example.org).
Submitted for Publication: June 30, 2012; accepted August 31, 2012.
Author Contributions: Drs Guy, Mohyuddin, Burchhardt, Olson, Eicher, and Brissett had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis. Study concept and design: Guy and Brissett. Acquisition of data: Guy, Mohyuddin, Burchhardt, Eicher, and Brissett. Analysis and interpretation of data: Guy, Olson, Eicher, and Brissett. Drafting of the manuscript: Guy and Brissett. Critical revision of the manuscript for important intellectual content: All authors. Statistical analysis: Guy, Olson, and Brissett. Administrative, technical, and material support: Mohyuddin and Brissett. Study supervision: Mohyuddin, Olson, Eicher, and Brissett.
Conflict of Interest Disclosures: None reported.
Additional Contributions: Michelle Naylor, MD, contributed to the original concept and design of the manuscript, and Prasanth Pattisapu, BA, provided editorial comments.