Extended endoscopic endonasal approach for resection of invasive pituitary adenomas

Objective To explore the surgical method and clinical effect of endoscopic endonasal approach for the treatment of invasive pituitary adenomas (IPA). Methods A retrospective analysis was conducted on the clinical data of 49 patients (50 procedures) with IPA treated through endoscopic endonasal approach at Department of Neurosurgery, the First Affiliated Hospital of Shenzhen University, from May 2014 to September 2017. Among them, the trans-cavernous approach was taken in 29 patients, the lateral-cavernous approach in 9 patients, the tuberculum sella planum approach in 7 patients and the diaphragma-sellae-cut and (or) dorsum-sellae-removal approach in 5 patients. The following aspects were investigated including extent of resection, curing rate and complications in patients with varying Knosp classifications and Hardy stages. Results Among all 50 procedures, gross total resection (GTR) was achieved in 34 cases (68.0%). Subtotal resection was in 10 case(20.0%) and 6 cases(12.0%) of partial resection. Biology cured 28 cases(57.1%, 28/49). The GTR rate for pituitary adenoma was 10/11 for grade 3 and 4/16 for grade 4 based on Knosp classification. The GTR rate was 9/10 for Hardy stage C, 10/12 for stage D and 6/19 for stage E. The rate of biology cure was 8/10 for stage C, 8/12 for stage D and 4/19 for stage E. Postoperative complications included 7 (14.3%) cases of cerebrospinal fluid leaks, 16 (32.7%) cases of electrolyte imbalance, 23 (46.9%) cases of transient diabetes insipidus, 16 (32.7%) cases of hypopituitarism, 2 (4.1%) cases of permanent hypopituitarism, and 1 (2.0%) case of epistaxis. The follow-up lasted 4-31 months with an average of 16 months. None reported recurrence in the group of GTR. One undergoing subtotal resection reported recurrence and received a second operation. Three patients underwent postoperative Gamma knife radiosurgery. Two patients with refractory IPA were administered temozolomide and metformin chemotherapy. Conclusion Based on the invasiveness of IPA, proper choice of endoscopic surgical approach could help with tumor resection and complication reduction.