Endoscopic-assisted maxillectomy: Operative technique and control of surgical margins

Background: When amenable to radical excision, cancer involving the maxilla is typically treated with max-illectomy followed by adjuvant therapy. Posterior tumor extension beyond the maxillary box leads to the invasion of complex areas, where achieving clear margins may be challenging. Methods: Patients undergoing endoscopic-assisted maxillectomy for nasoethmoidal, maxillary, or hard palate cancer between 2007 and 2017 were included in the study. Surgical technique, margin status, and recurrences were analyzed. Extension of posterior resection was classified in 3 types (type 1: resection of the pterygopalatine fossa; type 2: resection of the pterygoid plates and related muscles; type 3: resection of the upper parapharyngeal space). The analysis of putative risk factors for involvement of margins and local recurrence was performed with special focus on the posterior and medial margin. Results: The study included 79 patients (75 with available follow-up; mean: 20.6 months, range: 6-101 months), 37 (46.8%) of whom underwent type 1 resection, 34 (43.0%) type 2, and 8 (10.1%) type 3. According to pT category, 57 (72.2%) tumors were classified as T4a/T4b. Posterior and medial clear margins were achieved in 76/79 (96.2%) and 75/79 (94.9%) patients, respectively. T4b category, extension to the ethmoid, sphenoid sinus, pterygoid process, orbital cavity, and premaxillary tissues were significantly associated with a higher rate of margin involvement. None of the factors was significantly associated with medial margin involvement. Conclusion: Endoscopic-assisted maxillectomy combines several refinements including the facilitated detachment of the maxilla from the skull base and precise delineation of the posterior and medial margins of resection.