Surgical Outcomes of Intraconal Cavernous Venous Malformation According to Their Location in Four Right-Angled Sectors

The present study evaluated the surgical outcomes of intraconal cavernous venous malformation according to their location in 4 right-angled sectors. Data regarding the surgical method and approach, surgical outcome, and postoperative complications were retrospectively analyzed for 18 patients with intraconal cavernous venous malformations that were surgically treated at the authors' center between March 2006 and May 2017. The lesion location was defined using 2 perpendicular lines connecting the optic disc and the 4 surrounding rectus muscles in the coronal plane, which resulted in the formation of 4 right-angled sectors (upper-outer quadrant, upper-inner quadrant, lower-inner quadrant, and lower-outer quadrant). Accordingly, there were 3, 3, 8, and 4 lesions in the upper-outer, upper-inner, lower-outer, and lower-inner quadrants, respectively. Ten patients received anterior orbitotomy and 8 received lateral orbitotomy. There were no recurrences during the follow-up period. All patients exhibited reduced proptosis after surgery. Vision improved in 4 patients and remained unchanged in 14. Five patients experienced ocular movement limitation (1 permanent and 4 temporary), 1 developed an inferomedial blowout fracture, 2 developed a temporary sensory deficit, and 1 developed temporary ptosis. The authors' findings suggest that intraconal cavernous venous malformations most frequently occur in the lower-outer quadrant. Although most lesions can be removed via anterior orbitotomy, large lesions located near the orbital apex or on the orbital wall require lateral orbitotomy. Ocular movement limitation is a common complication and can become permanent in rare cases, necessitating close monitoring. Lesion location and surgical approach do not seem to influence the postoperative complication rate.