Assessment Of Mouth Opening After Release Of Maxillomandibular Fixation In Fracture Patients And The Effect Of Exercises Over Mouth Opening - A Prospective Study

Introduction

Fracture of the mandibular bone is the most common among facial bone fractures followed by midface fractures. The treatment objective is to reestablish the dental occlusion and masticatory function to premorbid state. Maxillomandibular fixation is a fundamental component and the mainstay in fracture management to ensure the interrelationship of dental occlusion. This can be brought about by various methods such as Arch bars, Ernst ligatures, bone supported devices including intermaxillary fixation screws, hanger plates and inter-arch miniplates, and interdental wires in case of dentulous arch and gunning splint in cases of edentulism. Open Reduction and Internal Fixation has overcome the disadvantages of prolonged intermaxillary fixation (IMF) such as pain, poor oral hygiene, phonetic disturbance, loss of effective work time, weight loss, reduced masticatory efficiency, and reduced mouth opening [1-3]. On the contrary, shortening the period of IMF compromises the fracture union. However, severe masticatory pull, loosening of IMF while placement of screws and TMJ positioning can pave way for malocclusion post internal fixation. This poses a need for postoperative IMF. This study aims to evaluate the mouth opening in patients who had undergone a maxillomadibular fixation post internal fixation treated in an institution in Kelambakkam.

Materials And Methods

Patients who reported to the Department of Oral and Maxillofacial Surgery, Chettinad Dental college and Research Institute during the period June 2017 - December 2021 after an alleged history of trauma were screened. Patients with head injuries and facial injuries other than the mandibular fractures or midface trauma were excluded from the study. Patient of either gender, aged 20 years or more, who are nonsmoker, nonalcoholic, and nonsubstance or intravenous drug abuser diagnosed with fracturewith no infection at the fracture site and no systemic comorbities were included in the study.Patients having fracture with no occlusal derangement and normal mouth opening or with previous history of limited mouth opening were excluded from the study.

Patients were treated with 1-3 weeks of maxillomandibular fixation after open reduction and internal fixation depending on the severity of malocclusion. They were also advised to refrain from strenuous physical activity during this period. Teeth in the fracture line were removed when indicated, and an antibiotic regimen was given preoperatively and for 3 days postoperatively. Weekly monitoring of the patientsweredone during the treatment period. On removal of the IMF, mouth opening was assessed on the day of removal of IMF, 1 week, 3 months and 6 months after removal. The values were recorded. Mouth opening exercises were done periodically and the rate of recovery was recorded.

Results & Discussion

Demographic details, year of the injury, type of fracture, amount of mouth opening at the time of diagnosis, fixation method, surgical procedure, period of immobilization, mouth opening exercise and amount the mouth opening after one week, one month and three months after release of IMF were assessed in 75 maxillofacial trauma patients who were treated by ORIF followed by IMF. They were statistically analysed using SPSS software version 2.0 and conclusions were drawn.

75 patients who reported to the Department and diagnosed with maxillofacial trauma were assessed and their mean age was 32± 2 years with 45% of the trauma reported during the year 2019. 56% of the patients were diagnosed with mandibular trauma, 29.33% with maxillary trauma and 28% with combined fractures. Open Reduction and Internal Fixation was done for all the patients followed by 1-2 weeks of immobilisation based on the severity of malocclusion post internal fixation.

Patients were found to have restricted interincisal mouth opening with a mean and standard deviation of 24.1±2.1 mm immediately after release of IMF. The patients were started with mouth opening exercises and the interincisal mouth opening was measured after 1 week, 1 month, 3 months and 6 months. The mean and standard deviation for the interincisal mouth opening in the periodic intervals were found to be 36.8± 2.91, 39.4± 1.64, 42.7± 1.67 & 45.67± 4.3 respectively (Tab 1, 2). The increase in mouth opening is contributed to the mouth opening exercises carried out on a regular basis. A comparison of the mouth opening after release of IMF among maxillary fractures, mandibular fractures and combined fractures was done using One-way ANOVA. There is no significant difference in mouth opening at any stage between the fracture types (Tab 3).

In closed reduction, the fracture heals in a process termed secondary bone union with callus formation [4]. Owing to the nature of the soft callus formed initially, protection is rendered in the form of bracing or internal fixation. Proper healing and ossification of callus is determined by adequate immobilization orelse this leads to fibrous union [5]. In this study, early release and early mandibular movement was started which had an added advantage of enhanced vascular and lymphatic circulation in the tissues around the fracturesite, with this slight functional stress imposed uponthe fracture site possibly accelerating consolidation. Other methods of shortening the IMF period is splinting of the lower jaw with an arch bar or acrylic splint or a period of soft diet [6]. According to Adeymeni Et Al [7] there might be betterment in restriction of mouth opening if the MMF could be shortened to a period of 2 weeks because there will be micromovement along the fracture line. This is justified because the most critical period of fracture healing is during first 2 weeks during which inflammation and revascularization occurs [8]. So there are studies which could justify that conventional method of 4-6 weeks [10] can be modified and it can be added with mouth exercises after a certain period of fixation.

Weight loss of 26.3% is observed in 93.7% of patients since they all consume only liquid or semisolid food till the release of IMF. Oral hygiene maintenance for patients were difficult and therefore periodic irrigation was done in order to maintain oral hygiene. There was no reported case of significant malocclusion after treatment of fractures however in contrast Al-belasy [9] reported a 13.3% of malocclusion in his study. The presence of postsurgical malocclusion depends on the number of fractures, degree of displacement, the time of mobilization and the reduction that can be achieved. The reason that there is no significant malocclusion in this study might be due to factors such as age, patients who are nonsmoker, nonalcoholic, and nonsubstance or intravenous drug abuser, patients with no systemic comorbidities or infection. Also, there was no reported case of infection after commencement of treatment. This could be due to the administration of intravenous antibiotics post surgeryfollowed by oral antibiotics for 1 week. Tab. Augmentin 625mg and Tab. Flagyl 400mg are the antibiotics that are given. This is similar to the study of Adeymi Et Al but this is in contrast to a report from a similar study by Al-belasy, who reported 2 patients with infection.

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Table 1:

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Table 1: Correlation of Period of immobilization and Mouth opening.

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Table 2:

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Table 2: Correlation of Interincisal Mouth opening after a period of mouth opening exercise.

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Table 3:

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Table 3: One-way ANOVA test to Correlate fracture type with mouth opening.

Conclusion

In this study, we conclude that there is evidence of reduced mouth opening even after a shortened period of IMF and also the reduced interincisal mouth opening had drastically rectified to the premorbid state after administration of mouth opening exercises. This signifies that these exercises play a significant role in the recovery to premorbid state which in turn improves the quality of life.