Mandibular invasion of squamous cell carcinoma: factors determining surgical resection of mandible using computerized tomography and histopathologic study.

Aim: Carcinoma of the mandibular region can be considered as an important, distinct entity associated with special problems relating to diagnosis, evaluation of extension, planning of treatment, surgical techniques, treatment result and prognosis. The study was aimed to assess the accuracy of computerized tomography in demonstrating mandibular invasion, to assess the role of anatomic structures like cancellous spaces, the inferior alveolar nerve and periodontal spaces in spread of carcinomas in the mandible and to determine the spread of tumour within the mandible and the resection procedure to be carried.

Materials And Methods: 11 mandibular specimens which were resected for squamous cell carcinoma were examined clinically, radiographically and histopathologically. Computerized tomography 120 KV, 40 to 130ma, obtaining slices starting from the center of lesion to the clearance, of the bone involvement distally and proximal to the lesion with excellent soft tissue or cortical bone interface with bone enhancement mode was used as a principle investigating tool to assess the tumour penetration in the mandible which was confirmed by histopathologic sections.

Results: A conditional probability test was conducted according to Bayes' theorem, and the results showed sensitivity 60% and specificity 77.8%, a false negative rate 40% and false positive rate 22.2%. A positive predictive value 69% and negative predicative value 70%.

Conclusion: In our study the factors to be taken into consideration in deciding the type of resection are the pattern of tumour infiltration, irradiated or non irradiated mandibles, presence or absence of dentition, the inferior alveolar nerve involvement and the periodontal space involvement. The computerized tomography has a significant role in detecting the involvement of tumour in the mandible with enhanced settings.