Opto-chiasmatic apoplexy as a compartment syndrome? Anatomical and surgical considerations on two bleeding cavernous malformations

Objective: Opto-chiasmatic (OC) cavernous malformations are sporadic lesions that are often misdiagnosed clinically and radiologically. Presenting symptoms range from incidental findings to the more frequent and dramatic “chiasmal apoplexy.” The present study aims to evaluate the potential role of arachnoidal membranes of the basal cisterns in the onset of OC apoplexy. A possible mechanism resembling a compartment syndrome is discussed through the description of two cases of bleeding cavernomas. Methods: We describe clinical, radiological, intraoperative findings in two cases of young patients presenting with OC apoplexy from bleeding cavernoma. The first was a 38-year-old man diagnosed with optic neuritis at the first episode of visual acuity deterioration. The second patient was a 22 -year-old woman who suffered two OC apoplexy episodes from a recurrence, which also presented with bleeding. Results: Both patients were operated on via pterional craniotomy and presented a postoperative improvement of visual symptoms. The second patient experienced deterioration 30 months after surgical resection due to rebleeding from a recurrence and required a second operation. Follow-up revealed a good recovery of visual disturbances; MRI at 6 and 3 years showed in both patients an apparent complete removal of the cavernous malformations. Conclusion: The cisternal environment where OC cavernous malformations develop and the paradigm of a compartment syndrome could explain the clinical presentation variability. This very rare subset of cavernomas would benefit from a classification system using ad hoc neuroimaging protocols and consistent indications.