The Laryngoscope V C 2011 The American Laryngological, Rhinological and Otological Society, Inc. Olfactory Groove Meningioma: Discussion of Clinical Presentation and Surgical Outcomes Following Excision Via the Subcranial Approach Jon-Paul Pepper, MD; Sarah L. Hecht, BA; Stephen S. Gebarski, MD; Erin M. Lin, MD, FACS; Stephen E. Sullivan, MD; Lawrence J. Marentette, MD, FACS Objectives/Hypothesis: To describe surgical outcomes and radiographic features of olfactory groove meningiomas treated by excision through the subcranial approach. Special emphasis is placed on paranasal sinus and orbit involvement. Study Design: Retrospective review of a series of patients. Methods: Nineteen patients underwent excision of olfactory groove meningioma (OGM) via the transglabellar/subcranial approach between December 1995 and November 2009. Nine patients had previously undergone prior resection at outside institutions, and four had prior radiotherapy in addition to a prior excision. Transglabellar/subcranial surgical approach to the anterior skull base was performed. Results: Tumor histology included three World Health Organization (WHO) grade III lesions, one WHO grade II lesion, and 15 WHO grade I lesions. Fourteen patients had evidence of extension into the paranasal sinuses, with the ethmoid sinus being most commonly involved. Kaplan-Meier estimates of mean overall and disease-free survival were 121.45 months and 93.03 months, respectively. The mean follow-up interval was 41.0 months, and at the time of data analysis three patients had recurrent tumors. Seven (36.8%) patients experienced a major complication in the perioperative period; there were no peri- operative mortalities. Orbit invasion was observed in four patients, with optic nerve impingement in 11 patients. Of these, three patients had long-term diplopia. No patients experienced worsening of preoperative visual acuity. Conclusions: Olfactory groove meningiomas demonstrate a propensity to spread into the paranasal sinuses, particularly in recurrent cases. Given a tendency for infiltrative recurrence along the skull base, this disease represents an important area of collaboration between neurosurgery and otolaryngology. The subcranial approach offers excellent surgical access for exci- sion, particularly for recurrences that involve the paranasal sinuses and optic apparatus. Key Words: Subcranial, olfactory groove meningioma, anterior skull base. Level of Evidence: 4. Laryngoscope, 121:2282–2289, 2011 INTRODUCTION Olfactory groove meningiomas (OGM) originate from the anterior cranial base, commonly at the cribri- form plate of the ethmoid bone, planum sphenoidale, and the frontospenoidal suture. Overall, they account for approximately 8% to 13% of the total of intracranial me- ningiomas. 1 Surgery is the preferred method of treatment, with radiation being withheld for cases of recurrent disease or high grade lesions. 2 The extent of primary surgery is thought to be the critical determi- nant of long-term cure rates. 3 Over the past 3 decades, surgical trends have emerged that favor radical resec- tion of OGM, including the dural attachment and any involved bone. This is tempered by the delicate adjacent anatomy, and despite efforts at complete resection the recurrence rates of OGM over 10-year follow-up periods have been as high as 41%. 4 Caudal extension into the paranasal sinuses is thought to be an important component in the pathogene- sis of recurrent OGM. 5 However, there is some disagreement if sinus invasion should dictate the surgi- cal approach, particularly in treatment of primary disease. Some groups have postulated that bulky sino- nasal extension in OGM is rare, and therefore is treatable with standard craniotomies. 1 Other institu- tions have found somewhat higher rates of sinus invasion, 6 and advocate use of modified craniotomies such as the subcranial approach for these cases. 7 Orbit invasion has also been described, 8 and when present will alter the planned approach. In the case of an OGM involving the sinuses and/or the orbit, radical resection entails resection of the involved portions of these bony structures. The creation of a communicating defect between the intracranial space and the sinonasal cavity may increase the associated risk of postoperative cere- brospinal fluid (CSF) leakage. Granted that entrance into the sinuses may be necessary for radical resection, expertise in reconstruction of skull base defects From the Department of Otolaryngology–Head and Neck Surgery (J.-P .P ., S.L.H., E.M.L., L.J.M.), Department of Neurosurgery (S.E.S.), University of Michigan Hospital System, Department of Radiology (S.S.G.), University of Michigan, Ann Arbor, Michigan, U.S.A. Editor’s Note: This Manuscript was accepted for publication May 10, 2011. Send correspondence to Lawrence J. Marentette, MD, FACS, Alfred Taubman Health Care Center, 1500 East Medical Center Drive, Floor 1-Reception A, Ann Arbor, MI 48109-5312. E-mail: Marentet@med. umich.edu DOI: 10.1002/lary.22174 Laryngoscope 121: November 2011 Pepper et al.: Olfactory Groove Meningioma 2282