A protocol for computer planning and intraoperative imaging as an aid to reconstruction of gunshot wounds to the face
Facial gunshot wounds result in extensive soft and hard tissue loss. Computer-aided surgical simulation has been described as an aid in the reconstruction of complex cranio-maxillofacial deformities, incorporating the creation of guide stents, cutting guides, and models, as well as use of intraoperative imaging to facilitate transfer of the virtual plan to the patient (1, 2). There are currently no guidelines for utilizing computer planning and intraoperative imaging in comprehensive reconstruction for patients with severe post-traumatic hard and soft tissue loss. The purpose of this investigation is to review our experience with computer-aided surgery in the setting of gunshot wounds to the face and propose a treatment protocol.
Materials and Methods:
Between January 2009 and March 2013, nine patients with complex, avulsive, facial gunshot wounds were managed according to a protocol utilizing computer-aided design/computer-aided manufacturing (CAD/CAM) software. The virtual plan was transferred to the patient via a combination of cutting guides, guide stents, and intraoperative navigation. Accurate placement of implants, bone grafts, and composite tissue free flaps was confirmed with intraoperative computerized tomography (CT). The protocol involves a staged approach to surgical reconstruction, beginning with: 1) damage/hemorrhage control, airway stabilization, and maxillo-mandibular stabilization, as indicated; 2) debridement of non-viable bone and soft tissue; 3) virtual reconstruction using commercially available craniomaxillofacial surgical simulation software, and “back-conversion” of virtual plan into navigation system; 4) navigation-assisted reconstruction of midfacial skeletal anatomy; 4) computer-aided oro-mandibular reconstruction with or without microvascular free tissue transfer using custom guide stents and cutting guides; 5) navigation-assisted, computer-aided palatomaxillary reconstruction with microvascular free tissue transfer using cutting guides and guide stents as indicated; 6) navigation-assisted reconstruction of the internal orbit; 7) confirmation of accurate reconstruction using intraoperative CT imaging.
Data analysis for this retrospective case series is limited to descriptive statistics obtained via chart review. Subjective comparison of the computer-assisted presurgical plan to the postoperative CT scan was completed intraoperatively. Jaw position, facial projection, separation of the nose and mouth, and oral competence was evaluated postoperatively at least one month after surgery.
All nine patients had severe disruption of the orbits, midface and mandible, with massive hard and soft tissue avulsion and oral-nasal communication. The computer-assisted surgery was successfully implemented in all patients and proved to be a useful adjunct for: the restoration of orbital volume, facial projection and symmetry; the inset of composite tissue free flaps, and the facilitation of dental implant supported prosthetic rehabilitation. Fibular free flaps were utilized to immediately reconstruct the maxilla and mandible in 6 patients, facilitating orthognathic jaw position, favorable facial projection, separation of the nose and mouth, and oral competence. The remaining patients were treated without microvascular free tissue transfer, but the virtual planning, pre-bent reconstruction plates, and intraoperative imaging significantly aided accurate reconstruction. Intraoperative CT scans facilitated recognition of minor inaccuracies in orbital plate placement in 2 patients, the position of which was corrected prior to leaving the operating room.
Computer-aided presurgical planning, custom cutting guides and guide stents, and intraoperative imaging have the potential to favorably affect the functional and aesthetic outcomes of patients with severe facial injuries resulting from gunshot wounds.
1. Bell RB. Computer planning and intraoperative navigation in cranio-maxillofacial surgery. Oral Maxillofac Surg Clin North Am. Feb;22(1):135-56, 2010.
2. Markiewicz MR, Bell RB. The use of 3D imaging tools in facial plastic surgery. Facial Plast Surg Clin North Am. Nov;19(4):655-82, 2011