Intraoral Wound Dehiscence After Open Reduction Internal Fixation of Mandibular Fractures: A Retrospective Cohort Study

Currently, the mandible is the second most frequently fractured adult facial bone, making it an important consideration for the maxillofacial surgeon.¹ Increased understanding of risk factors and the development of surgical techniques have markedly reduced post operative complications associated with mandibular fractures.^2,3 However, patients continue to experience postoperative complications such as intraoral wound dehiscence (IOWD). This complication is defined as separation of the margins of a closed surgical incision, with or without exposure of the underlying bone, usually occurring 3 to 7 days postoperatively.^4-6 When compared to cutaneous dehiscence, IOWD demonstrates accelerated healing and reduced scar formation⁷; however, IOWD is considered a troublesome postoperative sequel for both the surgeon and the patient because the bone surface is exposed to a variety of irritants and infective agents, subsequently delaying healing. Moreover, patients are adversely affected by other factors such as increased treatment cost, prolonged hospital stay, and the additional costs of sick leave.⁸ 

The prevalence of IOWD in Egypt is estimated to be 20% in angle mandibular fractures and 17% in the anterior symphyseal/parasymphyseal regions.^9,10 Despite this relatively high prevalence, IOWD is not a thoroughly investigated complication and no acceptable classification or management protocol has yet been identified.¹¹

More data are needed on the risk factors of IOWD among the medically fit individuals who constitute the majority of trauma patients. Investigating postoperative complications in patients with fractures requires special attention in Egypt, a heavily populated country with a high rate of road traffic accidents that constitute a major cause of mandibular fractures.^10,12 In Egypt, it is estimated that 50% of the total number of facial fractures affect the mandible.¹³ Therefore, updating guidelines would be helpful for the prevention and management of IOWD.

The present study aimed to determine the prevalence of IOWD that develops after treatment of mandibular fractures and to report the possible associated surgical factors in a cohort of medically fit patients. The study hypothesized that patient age, sex, fracture site, degree of displacement, and fixation type have no effect on IOWD prevalence.

This retrospective, analytic, observational study utilized data retrieved from archived clinical records of the Oral and Maxillofacial Department, Al Azhar University Hospitals in Cairo, Egypt during the period from January 2007 to December 2019. The study sample comprised patients admitted for open surgical fixation of mandibular fractures with or without subsequent wound dehiscence (Figure 1). The study was ethically approved by Al Azhar University Ethical Committee, and all patients signed informed consent forms preoperatively.

Inclusion and exclusion criteria

All patients who did not have diabetes, were not medically compromised such as patients with nutritional deficiencies or endocrine disorders, did not smoke, did not consume alcohol, and had mandibular fractures managed through open reduction internal fixation and via intraoral vestibular incision were included in the study (Figure 2, Figure 3). 

Mandibular fractures treated through extraoral incision were excluded. Data collected included demographic (age and sex) and surgical (fracture type, method of fixation, and fracture displacement) variables.

Intraoral wound dehiscence was assessed by 2 investigators through clinical examination using intraoral inspection and palpation 24 hours postoperatively when wound edges opened and exposed the underlying bone/plate/screw. Follow-up of all patients was conducted daily during the first week and weekly during the first month after surgery. Classification of IOWD was based on present or not (yes or no, respectively).

All patients who developed IOWD were managed conservatively through copious irrigation with warm saline and chlorhexidine mouthwash in intermittent cycles 5 times a day for 2 weeks. Where infection was present (which was determined by presence of pain, redness, bad odor, salty discharge, and lymphadenitis), antibiotic prescription and drainage were provided. 

Data were extracted from medical records into Microsoft Excel (Microsoft Corporation) by the first author and were later entered into SPSS software.

Epi Info software (Centers for Disease Control and Prevention) was used to calculate power of the study based on sample size of 69, 10.1% expected frequency of IOWD, one cluster and 1.0 design effect. This produced a power of study value between 80% (sample size: 60) and 90% (sample size: 98).

For the purpose of statistical analysis, patients were grouped according to demographic factors of sex and fracture-related factors of cause, side, site, displacement severity, fixation device, and infection. Statistical analysis was carried out using IBM SPSS Statistics for Windows, Version 21 (IBM Corp). Descriptive statistics were conducted to describe the study sample age range, mean, and standard deviation as well as frequency and percentage of independent study variable related to fracture type and surgical attributes. Cross-tabulation with Pearson chi-squared test was used to calculate the significance of associations between independent variables and IOWD. P was viewed as statistically significant at less than or equal to .05. 

Of the 69 patients included in the study (age range, 13–55 years; age mean, 28.13 ± 11.5 years), no statistically significant difference was noted between fractures occurring on the right and left sides. Fractures occurred more frequently in males (63, 91.3%); males constituted the majority of patients with IOWD. No flap augmentation or grafts were required in the observed cases, and all wounds healed completely after 2 weeks without the need for secondary closure (Figure 4).

None of the patient factors (age, gender), fracture factors (cause, side, site, displacement severity), or surgical factors (type of fixation device, infection) had a statistically significant association with IOWD occurrence (P >.05) (Table).

Statistically nonsignificant differences were noted regarding the occurrence of IOWD in the angle regions or the parasymphyseal areas (2 [20%] and 4 [11.4%], respectively) and the mandibular body or symphyseal regions (0 [0%] and 1 [5.3%]). 

Also, a nonsignificant difference was observed between the different fracture severity groups (P = .48). Patients with heavy locking and lag screw devices had less occurrence of postoperative IOWD than those with miniplates (2 [9.5%] vs 5 [17.2%]) (P = .15). Because all encountered cases presented with small dehiscent areas that had the same pattern of open wound edges and exposed underlying bone, dehiscence was not graded.

Among infected wounds, 1 (33.3%) had IOWD, representing 1.4% of the total overall dehiscence rate—that is, the majority of dehiscent wounds were not associated with infection. All mandibular fractures healed in all study cases, even in presence of IOWD. 

This study reports the experience of one surgical center regarding IOWD, with the aim of exploring possible associated risk factors and emphasizing appropriate methods in prevention and management of dehisced wounds. In the current study, IOWD affected 1 in 10 patients, regardless of patient age, sex, or other fracture-associated factors.

As discussed by Politis et al,¹¹ the factors that contribute to disturbed postoperative intraoral wound healing are either related to adverse local surgical factors or the patient’s medical condition. In the current study, all included patients were medically fit, nonsmokers, and nonalcohol drinkers, eliminating systemic predisposing factors. On the other hand, surgical technique could be linked to local factors that could predispose the patient to wound dehiscence. One of these factors is related to surgical closure, which could be attributed to loose sutures, insufficient closure of the deep subcutaneous musculature layer (mentalis muscle), or the presence of large profile irritating thick plate, which raises the flap from its underlying supporting bed. Moreover, excessive suturing will increase wound tension and result in failure of its healing.¹⁴ However, variability of these factors was eliminated in this study because the suturing technique used in all the study patients was based on use of a resorbable, interrupted type suture rather than a continuous suturing technique. This is in contrast to extraoral wound closure, where staples and glue may be used to supplement sutures.¹⁵

Previous studies in Egypt showed that IOWD is a common postoperative complication when compared to other complications such as limited mouth opening and malocclusion.^9,16 These findings are in contrast to those of Arpit Vashistha et al,¹⁷ who reported an IOWD prevalence of 0% after plate fixation of mandibular fractures. Additionally, other associated factors such as the severity of the fracture, existing laceration, and systemic factors such as malnutrition may contribute to the risk of wound dehiscence.^10,17 

The type of fixation device is a contributory factor whereby a large, thick plate placed along the inferior border is a preferred way to provide stable fixation without plate exposure through the dehiscent wounds.¹⁰ This can decrease wound dehiscence in  persons with single, minilocking and lag screws compared to persons provided a miniplate, especially at the superior tension band plates placed near the thin gingival region.¹⁰ The current study data are in contrast to the recommendation of Daif,⁹ who suggested the use of only 2 miniplates for the fixation of single-compound symphyseal and parasymphyseal fractures, and reported that this is sufficient to avoid wound dehiscence. According to the study on angle fracture fixation by Elsayed et al,¹⁰ IOWD prevalence was 30% in the miniplates group and 20% in the minilocking plates group. This is in agreement with the current study as well as the study by Ellis,¹⁸ which found a lower wound dehiscence rate with use of the single plate versus double plates. Similarly, Goyal et al¹⁹ did not find any statistically significant difference in IOWD between miniplates and lag screws, which further supports the results of this study.

Infection after fracture fixation may be another risk factor for IOWD. Sauerbier et al²⁰ reported an infection rate of 7.5%. However, the current study showed infection is not statistically associated with IOWD.

In the current study, measures used to control dehiscence included copious daily warm saline irrigation, intensive oral hygiene measures, and the use of chin pressure bandage during the first 24 hours postoperatively. This conservative approach (ie, no antibiotic therapy and no surgical curettage and closure are used) was considered the first line of management in cases of IOWD. In general, post-trauma fixation IOWD has a good prognosis; it may take a maximum of 2 weeks to obtain healing with secondary epithelialization of the bared bony sites without the need for regional flap reconstruction, resuturing, or grafting material.²¹ Meanwhile, different adjunctive techniques are available to decrease the potential for this postoperative complication and include the use of platelet-rich fibrin, adult stem cells, or collagen membranes, as well as hyperbaric oxygen therapy, which were not applied in the present study.²²

The study has limitations including the relatively small sample size, which was attributed to the strict inclusion criteria and involved otherwise healthy participants. However, the number of participants was statistically appropriate. The study was conducted in a unique geographical area, where scarce data on this topic were reported. The results of this study will hopefully provide more data on the rate and management of IOWD, especially in that the management aspect has historically been neglected by most researchers who attributed this complication to infection rate or mucosal inflammation.²¹ 

Intraoral wound dehiscence is a complication that occurred in 10.1% of the present mandibular fracture patients, independent of patient age and sex and regardless of fracture-related factors. Intraoral wound dehiscence has a good prognosis, and it may take a maximum of 2 weeks to obtain healing with secondary epithelization of the bared bony sites without the need for regional flap reconstruction, re-suturing, or grafting material. 

The authors are deeply indebted to Professor Osama Abu-Hammad, University of Jordan, Amman, Jordan, for his assistance in statistical analysis and for critically reviewing the manuscript. Many thanks to Dr Mohamed Moustafa-Farag, Researcher in Guangdong Academy of Agricultural Sciences and Dr Amre Elkelish, Assistant Professor of Plant Science, Faculty of Science, Suez Canal University, Egypt for their great help and scientific advice.

Authors: Shadia Abdelhameed Elsayed, PhD¹; Abdel Aziz Baiomy Abdullah, PhD²; Najla Dar-Odeh, FDS RCS³; and Alaa Abdelqader Altaweel, PhD⁴

Affiliations: ¹Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine for Girls, Al Azhar University, Cairo, Egypt, and Taibah University Dental College & Hospital, Al-Madinah Al-Munawwrah, Saudi Arabia; ²Assistant Professor of Oral & Maxillofacial Surgery, Faculty of Dental Medicine, Al-Azhar University for Boys, Assuit, Egypt; ³School of Dentistry, University of Jordan, Amman, Jordan, and College of Dentistry, Taibah University, Al Madinah Al Munawara, Saudi Arabia; and ⁴Assistant Professor of Oral and Maxillofacial Surgery, Faculty of Dental Medicine for Boys, Al-Azhar University, Cairo, Egypt, and Alfarabi Private College for Dentistry and Nursing, Jeddah, Saudi Arabia 

Correspondence: Shadia A. Elsayed, PhD, Associate Professor, Al Azhar University Department of Oral and Maxillofacial Surgery, Faculty of Dental Medicine for Girls, Nasr City, Cairo 11727 Egypt; shadiaelsayed@azhar.edu.eg 

Disclosure: The authors disclose no financial or other conflicts of interest.