Endoscopic endonasal surgery for olfactory groove meningiomas: outcomes and limitations in 50 patients

Recently, endoscopic endonasal surgery (EES) has been introduced in the management of skull base tumors, with constantly improving outcomes and increasing indications. The authors retrospectively reviewed the effectiveness of EES in the management of olfactory groove meningiomas.

Between February 2003 and December 2012, 50 patients (64% female) with olfactory groove meningiomas underwent EES at the University of Pittsburgh Medical Center. The authors present the results of EES and analyze the resection rates, clinical outcome, complications, and limitations of this approach.

Forty-four patients presented with primary tumors, whereas six were previously treated elsewhere. The patients' mean age was 57.1 years (range 27-88 years). Clinical presentation included altered mental status (36%), visual loss (30%), headache (24%), and seizures (20%). The mean maximum tumor diameter was 41.6 mm (range 18-80 mm). All patients underwent EES, which was performed in stages in 18 giant tumors. Complete tumor resection (Simpson Grade I) was achieved in 66.7% of the 45 patients in whom it was the goal, and 13 (28.9%) had neartotal resection (> 95% of the tumor). Tumor size, calcification, and absence of cortical cuff from vasculature were significant factors that influenced the degree of resection (p = 0.002, p = 0.024, and p = 0.028, respectively). Tumor residual was usually at the most lateral and anterior tumor margins. Following EES, mental status was improved or normalized in 77.8% of the cases, vision was improved or restored in 86.7%, and headaches resolved in 83.3%. There was no postoperative deterioration of presenting symptoms. Complications were increased in tumors > 40 mm and included CSF leakage (30%), which was significantly associated with lobular tumor configuration (p = 0.048); pulmonary embolism/deep vein thrombosis, more commonly in elderly patients (20%); sinus infections (10%); and delayed abscess months or years after EES (6%). One patient had an intraoperative vascular injury resulting in transient hemiparesis (2%). There were no perioperative deaths. During a mean follow-up period of 32 months (median 22 months, range 1-115 months), 1 patient underwent repeat EES for tumor regrowth.

Endoscopic endonasal surgery has shown good clinical outcomes regardless of patient age, previous treatment, or tumor characteristics. Tumor size > 40 mm, calcification, and absence of cortical vascular cuff limit GTR with EES; in addition, large tumors are associated with increased postoperative complications. Significant lateral and anterior dural involvement may represent indications for using traditional craniotomies for the management of these tumors. Postoperative CSF leakage remains a problem that necessitates innovations in EES reconstruction techniques.