A comparative analysis of the efficacy of cortical screws as lag screws and miniplates for internal fixation of mandibular symphyseal region fractures: a randomized prospective study

Abstract

The management of facial trauma is one of the most rewarding and demanding aspects of oral and maxillofacial surgery. Being the most prominent mobile bone of the facial skeleton, mandible fracture occurs more frequently than any other fracture. In this study, open reduction and internal fixation was performed for isolated mandibular symphyseal region fractures using cortical screws (as lag screws) in 40 patients and using miniplates in 40 patients. Clinical and radiological evaluations were made at 6 months postoperatively. Primary stability of fracture segments, postoperative swelling, restricted lip mobility, infection, wound dehiscence, implant removal, and mal-union or non-union of fracture segments was evaluated. Primary stability was achieved in 100% of cases treated with cortical screws, whereas for patients treated with miniplates, 97.5% attained primary stability, while one case (2.5%) showed persistent clinical mobility. Postoperative complications were noted in 13 (16.25%) of the total 80 patients. The duration of postoperative swelling was less in patients treated with cortical screws compared to patients treated with miniplates. It is concluded that cortical screw fixation is an effective procedure for the treatment of symphyseal region fractures, but the procedure is somewhat technically sensitive.

Traumatic injuries to the maxillofacial skeleton occur due to a variety of causes, such as road traffic accidents, sports injuries, interpersonal violence, gunshot injuries, etc. For the surgeon who operates on patients presenting with facial trauma, fractures of the symphyseal region of the mandible are a common entity. The mandible is the second most commonly fractured bone of the maxillofacial skeleton because of its position and prominence. Although there is wide variance in the reported percentage of fracture of the anterior mandible, aggregate analysis places this at approximately 17% of all mandibular fractures.

Internal fixation of mandibular fractures with miniplates (in conformity with the tension band principle) was first introduced by Michelet in 1973 and was later modified by Champy et al.

The lag screw technique in maxillofacial surgery was first advocated by Brons and Boering in 1970 and was later reintroduced by Niederdellmann et al., who stated that at least two screws were necessary to prevent rotational movement of the fragments in oblique fractures of the mandible. In North America, its use for the management of anterior mandible fractures became popular through the work of Ellis and Ghali. However, this modality has not gained popularity in India for unexplained reasons, resulting in the non-availability of essential hardware for lag screw fixation.

The purpose of this study was to compare the outcomes of treatment using either cortical screws (used as lag screws) or miniplates, in patients who had sustained a fracture in the mandibular symphyseal region. The objectives included comparative assessments of their ability to provide adequate primary stability, the need for any supplemental maxillomandibular fixation (MMF), the time required to complete the procedures, occlusal derangement, and the incidence of postoperative complications such as wound dehiscence, wound discharge, infection, postsurgical swelling, and any functional limitation in lower lip function as evidenced by speech articulation.

Patients and methods

This study was conducted on 80 patients with clinical and radiological evidence of fracture of the symphyseal region of the mandible. Patients were assigned to one of two groups: group A ( n = 40) were treated by open reduction and internal fixation using 2.0-mm miniplates, and group B ( n = 40) were treated by open reduction and internal fixation using 2.5-mm cortical screws applied using the lag screw principle.

Cases with discrete, isolated symphyseal/parasymphyseal fractures requiring primary definitive treatment, without any evidence of infection, were included in the study. Cases with uncontrolled systemic disease, multiple mandibular fractures, mal-union/non-union of fracture segments, and those requiring revision of previous improper treatment and comminuted fractures were excluded.

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Jan 19, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on A comparative analysis of the efficacy of cortical screws as lag screws and miniplates for internal fixation of mandibular symphyseal region fractures: a randomized prospective study
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