Titanium miniplates are commonly used in maxillofacial osteosynthesis treatments, including maxillofacial trauma and orthognathic surgery. Some crani-maxilloofacial surgeons have introduced the use of appropriate miniplates in the surgical treatment of maxillofacial fractures and have reported their usefulness.1–3 The titanium miniplate has higher biocompatibility and better physical properties than other metals tested. Therefore, titanium is potentially suitable as a permanent implant.4 However, reports exist on various complications related to indwelling titanium miniplates,5 and the complication risk is increased in miniplates indwelling for longer time.6 Currently, proper removal of indwelling titanium miniplates is controversial.
In this retrospective cohort study, including long-term follow-up, we examined the removal rates and reasons for removing titanium miniplate osteosynthesis materials following maxillofacial trauma surgery. We hypothesized that there was a difference in age and sex distribution relative to plate removal and in the timing of plate removal. We aimed to analyze the results of titanium miniplate removal procedures and determine the long-term safety and utility of titanium miniplates, considering the reasons or symptoms that contributed to plate removal.
MATERIALS AND METHODS
Study Design and Sample
We designed and implemented a retrospective cohort survey on the clinical, medical, and surgical records and radiographs of patients with maxillofacial trauma surgery with osteosynthesis. The study population comprised patients treated by four maxillofacial surgeons in a teaching hospital practice setting. All surgeries were performed at a single general hospital (Kagawa Prefectural Central Hospital, Japan) between April 2008 and March 2017.
Clinical indications for osteosynthesis using a titanium miniplate system were fractures of the maxilla, mandible, or zygomaticomaxillary complex (ZMC), including Le Fort I, II, and III fractures. Inclusion criteria were
- (1) maxillofacial fracture with rigid internal fixation using a titanium miniplate osteosynthesis system;
- (2) patient's complete medical records were available for evaluation;
- (3) availability of pre and postoperative radiographs or computed tomographic images;
- (4) regular clinical follow-up (minimum mandible, 3 months; midface, 6 months), documented by clinical and radiographic evaluation charts, at several days postoperatively and 3 and 6 months postoperatively until bone healing was observed at the fracture sites.
Exclusion criteria were
- (1) patients who did not meet the inclusion criteria,
- (2) who presented heavily comminuted fractures of the maxillofacial skeleton,
- (3) who could not participate until bone healing,
- (4) those with fracture reduction and fixation delayed for >1 month,
- (5) those with pathological fractures,
- (6) dentoalveolar fractures, or
- (7) atrophic mandibular fractures.
The primary outcome variable was titanium osteosynthesis plate removal. Secondary outcomes were indication for plate removal, time between insertion and removal, and plate removal cause. This study was approved by the Ethics Committee of Kagawa Prefectural Central Hospital (Approval No. 763).
The titanium plate system was Matrix MIDFACE, Matrix MANDIBLE and Compact series (DePuy Synthes, Zuchwil, Switzerland), KLS Martin, (Tuttlingen, Germany), or Walter Lorenz Surgical or Biomet Fixation systems (Zimmer Biomet Jacksonville, FL).
Surgery and Routine Postoperative Procedures
Maxillofacial fracture sites were secured with a plate according to the principles of Arbeitsgemeinschaft für Osteosynthesefragen Association for the Study of Internal Fixation. Le Fort I type fractures were treated with exposure of the anterior maxillary walls and pyriform aperture. After reduction of fractured segments, the maxillary segment was repositioned and fixed paranasally at the infrazygomatic crest using a plate and screws. ZMC fractures were stabilized using 2-point fixation at the maxillary-zygomatic vertical buttress via the maxillary vestibular approach and frontozygomatic suture via supraorbital eyebrow approach following the ZMC reduction. If the orbit was explored or reconstructed, a third fixation point at the infraorbital rim was used to stabilize the fracture. Osteosynthesis titanium plate systems for maxillary and midfacial fracture plates were 0.5 to 1.3-mm thick.
Mandible fractures were manually reduced using reduction tools and placed into maxillomandibular fixation using intermaxillary fixation screws with wires and heavy elastics. Internal fixation involved the two-miniplate technique for parasymphyseal, symphysis, and mandibular body fractures. Condylar fractures were fixed using the two-miniplate technique or one sheet of the three-dimensional subcondylar locking miniplate. An intraoral approach was adopted, and existing lacerations or extraoral approaches were selected according to the patient's condition. Osteosynthesis titanium plate systems for mandibular fracture plates were 1.0 to 1.5-mm thick.
The same procedures and postoperative clinical management were applied to all patients who received an intravenous antibiotic during surgery and on admission (cefazolin sodium, 1.0 g every 3 hours and 1.0 g every 12 hours, respectively); antibiotics were continued until postoperative day 3. Patients were discharged once they were deemed stable. The hospital contacted patients who had difficulty following up, and patients were instructed to seek medical attention when problems occurred.
Evaluation Methods and Postoperative Plate Removal
The primary outcome was the need for plate removal after maxillofacial trauma surgery, which was confirmed via reinvestigation of the medical inpatient and outpatient records and radiographs.
Clinical indications for plate removal were classified as removal owing to complications and removal without complications. Complications leading to plate removal were as follows:
- (1) infection due to wound dehiscence, with clinical features like swelling, pain, purulent discharge, or wound breakdown;
- (2) plate exposure, where a portion/complete plate was protruding through the skin or oral mucosa;
- (3) broken osteosynthesis devices;
- (4) palpable plates causing discomfort to the patient; and
- (5) screw loosening.
In the absence of complications, plate removal was performed for the following reasons:
- (1) patient request;
- (2) reconstructive/growth facilitation: plates removed during secondary reconstructive procedures, plates removed in children;
- (3) teeth extraction;
- (4) prosthodontic interference: where plates made the fabrication of removable dentures or placement of dental implants impossible.
Plate removal was performed on the portion of the plate that was problematic. Additional parts could be repaired or replaced as per the patient's request when performing plate removal with complications under general anesthesia or local anesthesia with intravenous sedation. Removal of plates by patient request was performed for all parts as requested by the patient.
We examined the predictive variables, including age, sex, fracture sites distribution, and time to plate removal in relation to primary outcome variables and plate removal with or without complications. Differences in the incidence of plate removal between patients with and without complication were presented.
Data were entered into a database using Microsoft Excel (Microsoft Inc., Redmond, WA). The database was transferred to JMP version 11.2 for Macintosh computers (SAS Institute Inc., Cary, NC) for statistical analysis. Differences in rates of complications and patient complaints between treatment groups were compared using Chi-square tests of independence and Fisher exact tests. A P value of <0.05 was considered statistically significant.
A total of 158 patients were included in the study. A total of 9 cases (mandible, 5; midface, 4) and 19 plates (mandible, 11 plates; midface, 8 plates) could not be followed up and were excluded from this study. Among these 185 patients, 440 miniplates were inserted and 272 miniplates were removed. In total, 116 patients (73.4%) had 282 miniplates (64.1%) removed (Supplemental Digital Content, Table 1, https://links.lww.com/SCS/B253).
We examined the patient's mean age (mean ± standard deviation) according to the surgical site. The mean age was 29.9 ± 15.9 (range: 20–91) years for those having plate removal and 47.8 ± 21.1 (range: 8–78) years for patients whose plates remained intact. There was a significant age difference between patients whose plates were retained, and those whose plates were removed (P < 0.001; Supplemental Digital Content, Table 2, https://links.lww.com/SCS/B253).
We examined the sex distribution of the patients according to the surgical site. Among patients whose plates were removed, there were no significant differences in sex relative to the presence or absence of complications. Of those whose plates were removed by the request of the patient, 40.7% were males (99/total number of fractures in 243 males), and 62.5% were females (34/total number of fractures in 72 females; Supplemental Digital Content, Table 3, https://links.lww.com/SCS/B253).
Distribution of Fracture Sites and Plate Removal from Fracture Site
Among patients with mandible fracture, 222 plates were removed (70.0% of total 317 mandibular plates) and 50 plates were removed (40.7% of total 123 maxilla-midface plates) in maxilla-midfacial fractures patients. In the mandible, 24 plates were removed because of complications (10.8% of the total removal mandibular plates) and 198 were removed for reasons other than complications (89.2%). Conversely, for maxilla and midfacial fractures, only 1 plate was removed in a patient because of complications (2.0% of the total removal maxilla-midface plates), and 49 plates were removed in for reasons other than complications (98.0%) (Supplemental Digital Content, Table 4, https://links.lww.com/SCS/B253). There was a significant difference in plate removal due to complications when comparing patients whose plates were placed in the maxilla-midface and mandibular regions (P = 0.0435).
Reasons for Plate Removal
In total, 199 plates (73.2% of all plates removed) were removed at the patient's request, despite having no complications (Supplemental Digital Content, Table 5, https://links.lww.com/SCS/B253).
Time to Plate Removal
The mean time to plate removal was 630.9 ± 863.0 and 258.0 ± 307.6 days in patients with and without complications, respectively (P < 0.0003). Plates were removed within 1 year in 164 fractures (240 plates), of which 11 (16 plates) were associated with complications and 153 (224 plates) were not. A total of 15 fractures (22 plates) had plate removed after 1 to 5 years, of which only 1 (2 plates) had complications and 14 (20 plates) did not. Seven fractures (10 plates) had plates removed after ≥5 years, of which only four (7 plates) had complications and three (3 plates) did not. Among patients who experienced complications, 1 fracture (1 plate) underwent plate removal in the maxilla, 10 (15 plates) in the mandible within 1 year, and 4 (7 plates) in mandible after ≥5 years, while only 1 (2 plates) required removal after 1 to 5 years (from the mandible) because of complications (Fig. 1).
We investigated plate removal after open reduction and internal fixation for maxillofacial fracture. Titanium plate fixation is renowned for its strength and biocompatibility and has now become a standard practice for several maxillofacial procedures, including craniomaxillofacial fracture treatment. The use of titanium plates in non-sterile fields and exposure to normal oral and maxillofacial forces may lead to complications such as infection or plate breakage. Thus, in many cases, removal of the osteosynthesis plate is required. A total of 4% to 18% miniplates are removed because of plate-related complications.7–9 Conversely, 33.8% to 40% plates are removed overall, including cases without complications.10,11 In some patients without plate-related complications, plate removal was performed for reasons like prevention of growth disorder or patient request. In this study, the plate removal rate was 61.8%. Of these, 90.8% plates were removed from patients who did not report any complication, whereas 9.2% plates were removed because of plate-related complications. Considering the total number of plates that were placed, 5.7% were removed because of complications. Comparatively, our study had a similar rate of removal secondary to complications. Our study demonstrated that the titanium miniplate is a safe and reliable osteosynthesis material with relatively few complications even with long-term indwelling plates.
The mean age of patients whose plates were removed following maxillofacial trauma surgery was 29.9 years, consistent with the previous reports that indicated high rates of plate removal in patients < 30 years old.5,12 In our study, there was no significant difference in patient age with and without complications, including those who retained their plates. Patients whose plates were removed, with or without complications, were significantly younger than those who retained their plates. This is likely because the ages of patients who had plate-related complications and who removed their plates but did not experience complications were similar. Consequently, this study provides important data regarding the relationship between age and plate removal.
There is a debate about the causal relationship between sex and plate removal. Pan et al. reported that males are more likely to have their plates removed than females because men had a high injury rate of maxillofacial fracture.9 Our findings differed. There were no significant sex-based differences with regard to the presence of complications among patients whose plates were removed. However, more females had their plates removed. In this study, 40.7% males and 62.5% females had their plates removed because they specifically requested removal. Therefore, sex is likely an important factor related to plate removal in patients without complications.
In this study, more plates were removed from the mandible than from the midface and maxillary region, consistent with previous reports.7,9,13–15 The highest plate removal rate due to complications in our study was observed in patients with mandibular angle and body fractures. Complications were commonly observed in patients with plates inserted into the mandibular angle and body, similar to past reports.9,12,14 Infection, exposure, and palpability were mainly associated with plates inserted in the mandibular body and external oblique line area in the mandible. These plates tend to directly lie under the mucoperiosteum and are prone to repeated trauma from mastication and dentures.13 Wisdom teeth, third molars in the mandible, can also contribute to infections.16 There seems to be no association between the presence or absence of wisdom teeth and occurrence of postoperative odontogenic infections.17,18 However, the frequency of periodontal disease associated with third molars is generally high; therefore, infections may occur more frequently than what is portrayed in the literature. We have experienced two cases of wisdom teeth-related infections in patients who underwent surgery for mandibular angle fractures. Thus, wisdom teeth extraction may be recommended for younger patients.
In the maxilla and midface regions, plate removal rates were low and rarely connected to complications. The reasons for removal included known infection, exposure, palpation, and thermal hypersensitivity.15,16,19,20 In this study, there was only one case of complications related to plate removal in maxilla and midface fractures. Some plates were removed because of patient's request; however, this never occurred in patients with middle facial fractures because of aesthetic concerns related to postoperative scarring. Therefore, routine plate removal in patients with maxillary middle facial fractures is not recommended.
In this study, in 90.8% of patients with plate removal, plates were removed without any complication. The most common was the removal of the plate at the request of the patient. In our previous study regarding plate removal after orthognathic surgery,6 the plate removal rate at the request of the patient was 19.6% but that after maxillofacial trauma surgery was clearly high at 69.5%. Many patients may also dislike keeping the plate after surgery and do not want to keep a memory of previous trauma.
The mean time to plate removal was 630.9 and 258.0 days in patients with and without complications, respectively, with no statistical significance in our study. This might be because plate removals in patients without complications mostly occurred because of patient requests or secondary to tooth extraction (i.e., the plate was removed early after bone healing). Among patients whose plates were removed because of complications, most removals occurred either before 1 or after 5 years postoperatively. Plate removal due to complications generally takes place within 1 year.7,9,12–14,21 Current evidence suggests that a foreign body like an osteosynthesis fixation device may act as a site for blood-borne bacterial growth.22 Dobbins et al23 reported that plates can become colonized with blood-borne bacteria, potentially increasing the prevalence of infection-associated symptoms. Thus, plate-related infections are a potential cause of plate removal. Our study results were consistent with those of past studies indicating that plate removals due to complications generally occur within 1 year. However, our analysis also indicated that removal likely occurred secondary to early or delayed complications. No plates that had been in situ for >30 months required removal.9,24 Our results contradict this finding. There were cases were plate removal was necessary because of complications after ≥5 years, in spite of no issues in the years immediately following the surgery. This might occur because problems are infrequent in young patients who are generally healthy; however, as the patient ages, the oral cavity and the whole-body environment change.
The long-term management of maxillofacial osteosynthesis plates remains controversial. Regarding the titanium osteosynthesis material, biological safety has been established.25 However, based on our findings, some plates required removal, although there were no plate-related complications, particularly in young female patients. Most complications occurred within 1 year; however, it was frequently necessary to remove plates after ≥5 years. Preforming long-term follow-up is difficult, and when treating patients with maxillofacial fractures, osteosynthesis plate selection is important. Sex and age should be considered, and the patient should understand the importance of long-term follow-up after maxillofacial trauma surgery. In recent years, development of bioabsorbable plates for the maxillofacial region26,27 as well as improvements in plate strength,28 biological safety,29,30 plate morphology,31 Biological characteristics of the plate32 and absorptive decomposition processes have been reported. However, complications unique to absorbability have also been reported. Thus, existing results should be compared with results from examinations of titanium osteosynthesis materials in the future.
This study is a meaningful study for patients with plates as treatment of maxillofacial fracture that are retained for a long-term. However, this is a retrospective cohort study at a single facility. Therefore, future multicenter collaborative research and prospective studies are warranted.
In conclusion, miniplates as osteosynthesis material are safe and useful for a long period of time with relatively few complications. However, several patients without complications whose plates were removed were young females. Treatment plans should consider the patient's age and sex when selecting plates. Because of complications, plate removal risk is the highest within 1 and after 5 years postoperatively. Therefore, long-term follow-up is essential in patients whose plates are retained for >1 year.
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