Internal and external spheno-orbital meningioma varieties: different outcomes and prognoses

Internal variation among spheno-orbital meningiomas (SOM) is surgically challenging. Optic canal invasion management is discussed.

This retrospective study includes 70 patients with SOM who underwent surgery between 1995 and 2012. Preoperative ophthalmological, neurological and aesthetic clinical signs were collected. All patients benefitted from repeated tomography and magnetic resonance imaging (MRI). The surgical team consisted of a neurosurgeon and a plastic surgeon. In the majority of cases, resection was followed by bone reconstruction using an autologous iliac crest graft. The extent of resection was evaluated on the dural and osseous sides. Early clinical outcomes, long-term follow-up, recurrence and adjuvant therapies were reported.

The mean age was 52 years old, and 91 % of the patients were women. Initial symptoms primarily included proptosis (65 %), decreased visual acuity (39 %) and soft tissue tumefaction (16 %). We classified 40 cases as the internal variety when considering the inner third of the greater wing of the sphenoid, optic canal, anterior clinoid process or cavernous sinus. The remaining cases were described as the external variety. The complete resection rates for the internal and external varieties were 12 % and 61 %, respectively (P < 0.001). In total, 90 % of cases were grade I meningiomas. For grade I, we reported 30 % recurrence, and 50 % of these cases recurred in the first 2 years. Grade II cases without early adjuvant radiotherapy increased at 2 years. We did not observe any difference in recurrence rate among grade I tumours with or without tumour remnants. At the end of follow-up, visual acuity was stabilised or increased in 88 % of patients. In addition, 14 % of patients experienced persistent pain at the location of the iliac harvesting site.

The internal SOM variety exhibited a reduced total resection rate and a shorter progression-free survival (PFS). Unroofing of the optic canal extended PFS. Among grade I cases, the persistence of a negligible tumour remnant did not alter the probability of recurrence. For superior grades, radiotherapy must be administered in addition to surgery as soon as possible. SOMs require prolonged follow-up. Autologous iliac reconstruction is related to substantial morbidity and could be replaced by prosthetic bone three-dimensional reconstruction.