Sphenoorbital Meningioma: Surgical Series and Design of Intraoperative Management Paradigm

Introduction: Sphenoorbital meningiomas (SOMs) are slow-growing infiltrative lesions that are complicated by extensive hyperostosis of the skull base, and characterized by distinct morphological and clinical features. The primary treatment for symptomatic or growing SOM is surgical removal. The main surgical goals are reduction of proptosis and restoration of visual function.

Methods: We retrospectively reviewed 27 consecutive patients treated surgically for SOM between 2006 and 2014, with special attention to clinical and radiological presentation, surgical technique, and long-term outcome. Primary outcomes were defined as postoperative visual function and radiological exophthalmos, which were compared with the preoperative baseline. The affect of multiple variables on these outcomes was statistically analyzed, including three specific surgical stages: performing anterior clinoidectomy, placing epidural autologous fat graft, and reconstructing the orbit with rigid material.

Results: Study cohort comprised of 24 women and 3 men with mean age of 53.3 ± 12 years (range 27–78 years). Clinical proptosis was the most common presenting sign, followed by visual loss, with rates of 92 and 37%, respectively. Preoperatively, radiological exophthalmos was evident in all patients (EI>1). Complete tumor resection (Simpson grade I/II) was achieved in 51.8%. Extent of resection was limited in 13 cases due to dural invasion to the cavernous sinus (61.5%), superior orbital fissure (84%), and the intraorbital intraconal space (15%). Low rates of both tumor recurrence after complete resection (7.4% in 40.7 average follow-up months) and progression of residual tumor (3.7%) are reported. Surgical resection caused visual improvement in 80% of the patients with impaired vision, and exophthalmos reduction in 77% of the cases. The postoperative reduction of the mean EI was statistically significant (p < 0.05). Univariate analysis showed two parameters to be statistically significant factors affecting favorable response of visual status to surgical treatment: preoperative visual deficit (p = 0.0001), and optic canal involvement (p = 0.04). Two other parameters, cavernous sinus involvement and incomplete tumor resection, showed a tendency toward favorable response, but failed to reach statistical significance. Surgical complications mainly included transient morbidity secondary to cranial nerve injury; Long- term postoperative neurological deficit includes 1 patient with permanent oculomotor nerve palsy (3.7%), and 1 patient (3.7%) with transient decrease in visual acuity that improved gradually. None of the patients experienced postoperative complication that prompted second intervention. Specifically, there were no cases of postoperative epidural hematoma or acute enophthalmos.

Conclusions: Surgical goals in the treatment of SOM should be the relief of leading symptoms rather than complete tumor resection, which is commonly limited by tumor invasion to the superior orbital fissure, cavernous sinus, and extraocular muscles. Therefore, tailoring the surgical technique to individual cases is encouraged. According to our experience and review of existing literature, we present an optional intraoperative management paradigm for surgical removal of SOMs, which incorporates selective anterior clinoidectomy, elimination of epidural dead space by placing autologous fat graft, and selective rigid orbital reconstruction. Satisfactory visual, cosmetic and oncological results as well as low morbidity were achieved by following this paradigm.