Endoscopic Craniofacial Resections and Endoscopic-Assisted Craniofacial Resections for Locally Advanced Anterior Skull Base Tumors. Early Experience of a Canadian Tertiary Referral Centre

Introduction: Tumors involving the anterior skull base are challenging due to the complex anatomy and critical structures that may be involved. Traditionally, open craniofacial resection and various trans-facial approaches have been employed in the surgical management of such tumors. Recently, Endoscopic Craniofacial Resection (eCFR) and Endoscopic-assisted Craniofacial Resection (e-aCFR) have proven to be effective in selected patients, showing similar oncologic outcomes and some significant reduction in complications and morbidities.

The objective of this study was to evaluate the early outcomes, pitfalls and complications of our series of patients who underwent endoscopic, or endoscopic-assisted approaches for skull base tumors in the past 3 years.

Methods: Retrospective analysis of the medical charts of patients with anterior skull base tumors treated with eCFR and e-aCFR, from January 2013 to September 2015.

Results: A total of 14 patients underwent eCFR or e-aCFR for anterior locally advanced skull base tumors (9 eCFR and 5 e-aCFR). This included 11 malignant pathologies and 3 benign tumors.

The malignant pathologies included 7 Esthesioneuroblastomas - 5 with very locally advanced disease (4 with T4 or Kadish C, and 1 T3 or Kadish C), 2 with moderate advanced disease (2 Kadish B or T2). 2 Adenocarcinomas (T4b), 1 Neuroendcrine carcinoma (T4b) and 1 SNUC (T4a). Of the malignant tumors, 2 were previously treated with radiotherapy and 2 were previously surgically resected.

Of the benign tumors, 1 was an Inverted Papilloma (T4) and 2 Fibro-osseous lesions.

For skull base reconstruction, Nasoseptal flaps were used in 8 patients (57%), Fascia Lata grafts in 6 (43%), synthetics Dural repair in 5 (36%), pericranial flaps in 3 (21%), and fat grafts in 2 (14%) and Titanium mesh in 1 case (7%).

Of the malignant tumors, 4 (36%) patients underwent adjuvant treatment after surgery. 3 (27%) received a combination of Radiotherapy and Chemotherapy and 1 (9%) patient was treated with Chemotherapy alone. Only 1 (9%) patient had neo-adjuvant Chemotherapy.

The average length of follow-up was 11 months (range from 1 to 18 months). All patients are alive at submission for publication. 4 (36%) of the 11 locally advanced malignant tumors developed recurrences; the average time between recurrence and surgery was 13 months. 2 (50%) of these recurrences were treated as a rescue surgery for previous radiotherapy and 3 (75%) of them did not have adjuvant treatments after surgery. There were no recurrences on the benign tumors subgroup.

Compications included 3 (21%) postoperative CSF leaks, 2 immediately postoperatively and 1 delayed, presenting with meningitis (no neurological sequela). 1 patient had intractable intraoperative seizures and 1 patient developed isolated seizures during adjuvant radiotherapy. None of these patients have long-term sequela.

Conclusions: For selected cases, eCFR and e-aCFR is a safe and effective alternative in the treatment of locally advanced tumors involving the anterior cranial base. Recurrences were found more frequent in previously treated patients and those who did not receive adjuvant treatment. Multidisciplinary approach to these complex lesions is essential to archive favorable outcomes.