Volumetric Analysis of Nasopharyngectomy via Endoscopic Endonasal, Maxillary Transposition, and Lateral Temporal-Subtemporal Approaches.

OBJECTIVE: This project develops a computer model that allows volumetric analysis of the exposure afforded by an endonasal-endoscopic approach, maxillary transposition, and lateral temporal-subtemporal approaches during a nasopharyngectomy. The model will demonstrate idiosyncracies of these approaches, including sacrifice of normal tissues, ease of instrumentation, and gate of entry. SUBJECTS AND METHODS: Computed tomographic scans of an anatomic specimen were used to create computer simulations of the endoscopic endonasal, maxillary transposition, and lateral temporal-subtemporal approaches for T1and T4 nasopharyngeal carcinoma; therefore, allowing assessment of their surgical corridor using Intuition, a software that allows a semiautomated computerized segmented volumetric analysis.
RESULTS: The smallest volumes of tissue mobilization or removal were observed during the endoscopic-endonasal nasopharyngectomy. The volumes of tissue mobilization for the maxillary transposition approach were higher than those of lateral temporal-subtemporal approaches.
CONCLUSIONS: This model adds to our understanding of select surgical corridors to the nasopharynx. It suggests that an endoscopic-endonasal approach requires less manipulation or resection of smaller volumes of normal tissue to expose a nasopharyngeal tumor than the lateral temporal-subtemporal and maxillary transposition approaches. It also, however, requires instrumentation through a smaller entry gate implying greater difficulty. Nonetheless, these factors should not be construed as superiority of one approach over the other. Factors that are important in the choosing of the surgical approach, such as surgeon's training and experience, invasion of neurovascular structures and method of reconstruction are not considered in this model.