Surgical and functional outcome of olfactory groove meningiomas: Lessons from the past experience and strategy development.

OBJECT

Olfactory groove meningiomas (OGMs) constitute a unique subset of intracranial meningiomas, since they usually remain clinically silent for a long period of time, and they may be of large size upon their diagnosis. Their surgical management remains quite challenging. The surgical and the neuropsychological outcome of patients with OGM are presented in our current study, in order to establish a basis for developing efficacious surgical strategies for the management of this clinico-pathological entity.

METHODS

A retrospective study covering a 17-year period examined a total of 78 patients (31 males and 47 females) diagnosed with OGM, and surgically managed in the two participating institutions (Greece and Romania). The patients' charts as well as their imaging studies (head CT, brain MRI/HMRS, brain MRA/MRV, cerebral DSA), and their operative reports were carefully reviewed. All participants underwent pre- and post-operative neurocognitive evaluation with the Mini Mental Status Examination (MMSE), and the Frontal Assessment Battery (FAB). Microsurgical resection was performed by employing a bilateral subfrontal, a unilateral subfrontal, or a pterional approach. The Simpson scale was utilized for assessing the extent of resection. The histological type of the resected meningioma was identified. The follow up period ranged from 2 to 15 years (mean: 5.6).

RESULTS

Non-specific headache was the most common presenting symptom, followed by personality changes in our series. Grade 1 Simpson resection was accomplished in 19.2%, grade 2 in 46.2%, grade 3 in 17.9%, and grade 4 in 16.7%. The most common postoperative complication was anosmia (89.7%), followed by CSF leakage (21.8%). The observed 5-year recurrence rate was 11.8%. Analysis of our data demonstrated that patients with larger tumors presented with poorer neurocognitive status, and had also lower, compared with patients with smaller meningioma, postoperative neurocognitive outcome. Meningioma's histological type had no correlation with complication occurrence or tumor recurrence. Surgical resection significantly improved the preoperative MMSE scores of our patients, while the observed postoperative improvement of the FAB scores was not statistically significant. The bilateral subfrontal approach demonstrated higher complication rate than the other two approaches, in our series. Interestingly, bifrontal approach was associated with higher tumor recurrence rate. Tumor size, patient's age, and ethmoid bone infiltration seem to be predisposing factors for complication occurrence and tumor recurrence.

CONCLUSION

Individualized surgical strategy is necessary for mitigating the postoperative complication rate, and the possibility of recurrence in the management of OGMs. The exact role of less invasive, endoscopic approaches in the management of these patients remains to be defined.