Transverse lag screw fixation in midline mandibulotomy - A case series

Vertical midline mandibulotomy has provided a relatively simple and efficie nt means of obtaining access to intraoral tumors that are too large or too posterior to be removed transorally. Midline mandibulotomy has had the adva ntage of nerve and muscle preservation and places the osteotomy outside the typical field of radiotherapy. in contrast to lateral and paramedian osteo tomies. Flare and screw fixation has been the usual means of osteosynthesis for these mandibulotomies; however, plate contouring over the symphyseal s urface has been a time-consuming process. Unless the plate was contoured ex actly, mandibular malalignment and malocclusion in dentulous patients has o ccurred. Use of parallel transverse lag screws has become a popular method of osteosynthesis for parasymphyseal fractures, and we have extended their use for mandibulotomy fixation. This paper reports our clinical experience with transverse lag screw fixation of midline mandibulotomies in 9 patients from 1994 to 1997. There were 7 men and 2 women with a mean age of 56 (ran ge 35 to 71 years). The pathological diagnosis in all patients was squamous cell carcinoma: 8 cases were primary. and 1 patient presented with recurre nt tumor. No tumors involved the mandibular periosteum. One patient had had previous radiotherapy, and 3 patients underwent postoperative radiotherapy . The mean follow-up ha been 17 months (range 9 to 27). There was 1 minor c omplication and 1 major complication related to our technique. The major co mplication was a delayed nonunion of the mandibulotomy. This occurred becau se the 2 parallel screws were placed too close to one another, and this pla cement resulted in a delayed sagittal fracture of the anterior cortex and s ubsequent nonunion. Transverse lag screw fixation has not affected occlusio n in our dentulous patients. Speech and diet were normal in the majority of our patients. Transverse lag screw fixation of the midline mandibulotomy h as been a relatively safe, rapid. and reliable method for tumor access and postextirpation mandibular stabilization and has significant advantages ove r other current methods of mandibulotomy and fixation.