Colles external fixator as alternative in comminuted mandibular fractures treatment

Objective: to report a surgical case of comminuted mandible fracture caused by a firearm projectile treated with external fixation. Methodology: male patient, 18 years old, attended the Emergency Department of the Maxillofacial Surgery service after trauma in the mandibular region by a firearm projectile. On clinical examination, edema was observed in the cervical zone II and mandibular region, penetrating orifice of entry of the projectile in the genial region and mobility in the mandibular body. CT scan revealed a comminuted fracture in the mandible. Transcutaneous perforations were performed with pins, anatomical reduction of the fracture and stabilization to the external nail, adapting to the mandibular anatomy. Following postoperative follow-up, the patient progresses without pain complaints, with functional and satisfactory mouth opening, without mobility in bone fragments, and reestablished mandibular Research, Society and Development, v. 9, n. 10, e1879108030, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i10.8030 3 framework. Results and Conclusion: mandibular fractures by firearms are frequent in the routine of the buccomaxillofacial surgeon. Cases of bone comminution present individual peculiarities that must be taken into account in their management. The correct indication of external fixation proved to be adequate and satisfactory for cases of mandible comminution.


Introduction
In the last years the management of mandibular fractures due to firearm injury has undergone significant changes. Several treatments are reported in the literature, including the use of steel wires, maxillomandibular block, internal fixation with miniplates and screws and, in some cases, the use of external fixation (Ellis & Bretta, 2007;Ellis, Muniz & Anand, 2009).
The treatment of comminuted mandibular fractures by firearm injury is still a controversial thematic when it comes to knowing the best moment for the surgical approach (Abreu et al. 2009), as well as to which fixation method is the ideal and can be used in all cases. Some factors influence in the conduct and decision making, such as the bad dentition, the inadequate nutrition of the patients, soft tissue and bone fragments aspect, fixation materials availability and surgeon's experience (Holmes, Hardee & Anand, 2002).
In the beginning, the accepted idea for treating these fractures included the maxim that surgical exploration would lead to loss of blood supply of bone fragments, what would cause a bigger incidence of bone sequestration, necrosis and outbreaks of infection, but this theory was modified (Smith & Teenier, 1996). Another modified factor refers to the idea of "sterile injury", it is now known that the heat generated by the propellant discharge and friction between the bullet and the cylinder are not sufficient to sterilize the projectile, what justifies those being contaminated injuries (Abreu et al. 2009).
Currently most of these lesions have been treated with open reduction and the use of functionally stable internal fixation. This technique provides the return of the mandibular form and function, good bone consolidation and enables some comfort to the patient 2 however, the use of external fixators is an option for treating mandibular firearm injuries, and is now an uncommon choice in the treatment of these fractures (Gibbons, Mackenzie & Breederveld, 2011) nevertheless, when correctly indicated, it is an effective therapy. Research, Society and Development, v. 9, n. 10, e1879108030, 2020 (CC BY 4.0) | ISSN 2525-3409 | DOI: http://dx.doi.org/10.33448/rsd-v9i10.8030 5 The objective of this paper is to present a clinic case of comminuted fracture in the mandibular body region caused by a firearm injury, treated with an orthopedic device of external fixation, as well as to discuss about indications, limitations, management and clinic experiences showing that, when correctly conduced, the use of these fixators is a viable alternative in the surgical treatment of traumas caused by firearm injuries in the mandibular region.

Methodology
A descriptive observational study was carried out, whose objective is to present, by means of a case report and bibliographic survey, scientific data on the topic addressed. (Pereira, et al., 2018). The study has a descriptive and qualitative content, once that it considers the studied reality and intends to expose the details. There was no need for approval by the Research Ethics Committee, considering that it is a case report. However, the patient authorized the use of images, clinical, radiographic and socioeconomic data for educational and research purposes and signed an informed consent form (ICF).   Note the initial surgical aspect (gunshot injury) and the three-dimensional reconstruction of the preoperative computed tomography and axial views with bone fragments.

Case Report
In the intraoperative time, a maxillary-mandibular blockade using steel wire was performed, surgical cleaning with copious irrigation with 0.9% saline and 2% chlorhexidine, removal of viable projectile fragments and suture of the entrance orifice. Closed fracture treatment and stabilization using the external fixation system were chosen by adapting an external wrist fixation -Colles fixator. Methylene blue was used for demarcating the fracture zone and the mandibular base; through small incisions and transcutaneous trocar.