Three-Dimensional Exoscopic Temporal Bone Resections for Advanced Head and Neck Cancer

Background: The three-dimensional (3D) exoscope has several advantages over the operative microscope including improved ergonomics, reduced space occupancy and broadened teaching ability. Small series have described its successful use in lateral skull base surgery for temporal bone encephaloceles, vestibular schwannomas, cochlear implants, and more, but none have described its use for lateral skull base resections in the context of malignancy.

Objectives: We sought to investigate the surgical characteristics and outcomes of temporal bone resections (TBR), both lateral (LTBR) and subtotal (STBR), with sole visualization via the three-dimensional exoscope for complex head and neck cancers.

Methods: A retrospective chart review of all patients undergoing LTBR or STBR with the Karl Storz VITOMÒ 3D exoscope from the start of its availability at our tertiary care center in August 2016 until August 2019 was performed. Demographic information was collected. Tumor type, staging, margin status, recurrence rate and survival were descriptively analyzed.

Results: Fifty-five patients underwent exoscopic temporal bone resections from 2016 through 2019, of which 18% (n = 10) underwent STBR. The mean age was 67 ± 14 years, and the majority (89%, n = 49) of patients were male. Most tumors were of cutaneous origin (62%, n = 34), followed by primary parotid gland tumors (27%, n = 15). Preoperatively, 64% (n = 35) of patients had a cranial nerve VII deficit. Based on the histologic type and AJCC 8th Edition staging guidelines, 51% (n = 28) were considered to be at least a size T4, and 42% (n = 42) were considered to be at least a size T3. These TBR were often a part of a larger oncologic resection which included most commonly infratemporal fossa resections (87%, n = 48), auriculectomies (47%, n = 26), mandibulectomies (53%, n = 29), parotidectomies (96%, n = 53), and other procedures. On final pathology, 24% (n = 13) had microscopically positive margins, 49% (n = 27) had lymphovascular invasion and 80% (n = 44) had perineural invasion. Twenty-six patients required adjuvant therapy, of which 65% (n = 17) underwent radiation alone, and 35% (n = 9) underwent combined chemotherapy and radiation. Over the study period, 20% (n = 11) of patients had recurrences, with a median recurrence time of 5 months (range, 2–30 months).

Conclusion: The 3D exoscope is an oncologically sound alternative to the operative microscope for LTBR and STBR in the context of advanced head and neck cancer. Its ergonomic and spatial properties are particularly advantageous during these cases, which require larger surgical set-ups, necessitate prolonged operative time, and include more learners and operative team members.

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