Link, Michael J.

Abstract Background The far-lateral approach is an effective skull base technique that provides access to the lower clivus and premedullary area. This approach is also useful for maximal visualization and resection of large posterior fossa tumors with extensive medial extension, especially when aggressive resection is ideal for a malignant tumor in a young patient, or it is technically challenging because of tumor calcification. We demonstrate a microsurgical operative video to describe technical pearls in this difficult situation. Case Presentation A 45-year-old man with history of “hoarseness” for up to two decades was presented with imbalance and mild dysphagia over 3 years. Imaging demonstrated a 55-mm left cerebellopontine angle (CPA) tumor extending medially across the midline with severe calcification (Figs. 1 and 2). His neurological examination revealed left facial numbness, complete left facial weakness, left deafness, complete left vocal paralysis, as well as severe left hemibody ataxia. The tumor was resected via a left suboccipital craniotomy with far lateral approach including drilling to the occipital condyle and C1 laminectomy. Initial manipulation of the inferior pole of the tumor resulted in asystole which was managed successfully with glycol pyrolate. Pathology demonstrated IDH-1 wild type, MGMT-methylated glioblastoma. The patient subsequently underwent adjuvant chemoradiation. Conclusion The far-lateral approach is an effective approach for maximal safe resection of a malignant brainstem, cerebellar, and CPA tumor.The link to the video can be found at: https://youtu.be/AIGebJPJEnw.

Abstract Background Consensus in timing of radiotherapy is yet to be established in esthesioneuroblastoma (ENB). Objective This study was aimed to investigate if planned adjuvant radiotherapy improves tumor control after complete margin negative resection of low Hyams' grade (1 or 2) ENB. Methods A retrospective review of patients with pathologically confirmed negative margin resection of Kadish's stage B or C and Hyams' grade 1 and 2 ENBs was conducted. Seventeen patients meeting the criteria were divided into the following two groups for cohort study: (1) those who underwent planned immediate postoperative adjuvant radiotherapy (IR group) and (2) those who did not (delayed radiotherapy [DR] group). Results The IR group included nine patients (Kadish's stage B in one and stage C in eight; Hyams' grade 1 in two and grade 2 in seven). Mean follow-up was 140.8 months. Seven patients (78%) had disease progression (DP) at a median of 88 months (four with cervical lymph node metastasis [CLNM], one with distant metastasis, and two with both local recurrence and CLNM). One patient experienced frontal lobe abscess. The DR group included eight patients (Kadish's stage B in six and stage C in two; all Hyams' grade 2). Mean follow-up was 123.3 months. Four (50%) patients who developed DP (all local recurrence) were salvaged with surgery and adjuvant radiotherapy at a median of 37.5 months. There was no statistically significant difference in DP rate (p = 0.23), time to DP (p = 0.26), or the local tumor control rate (p = 0.23). Conclusion In our limited cohort, immediate postoperative radiotherapy did not demonstrate superiority in tumor control, although risk of radiotherapy toxicity appears low.

AbstractEsthesioneuroblastoma (ENB) is a rare olfactory malignancy that can present with locally advanced disease. At our institution, patients with ENB in whom the treating surgeon believes that a margin-negative resection is initially not achievable are selected to undergo induction with chemotherapy with or without radiotherapy prior to surgery. In a retrospective review of 61 patient records, we identified six patients (10%) treated with this approach. Five of six patients (83%) went on to definitive surgery. Prior to surgery, three of five patients (60%) had a partial response after induction therapy, whereas two of five (40%) had stable disease. Microscopically margin-negative resection was achieved in four of five (80%) of the patients who went on to surgery, while one patient had negative margins on frozen section but microscopically positive margins on permanent section. Three of five patients (60%) recurred after surgery; two of these patients died with recurrent/metastatic ENB. In summary, induction therapy may facilitate margin-negative resection in locally advanced ENB. Given the apparent sensitivity of ENB to chemotherapy and radiotherapy, future prospective studies should investigate the optimal multidisciplinary approach to improve long-term survival in this rare disease.