[Venous cerebral complications after microsurgery for complex aneurysms of the middle cerebral arteries].

Microsurgeries are common for complex aneurysms of the middle cerebral artery (MCA).

Objective: To evaluate the incidence and types of venous cerebral disorders after microsurgeries for complex MCA aneurysms.

Material and methods: A retrospective study included 285 patients with complex MCA aneurysms between 2009 and 2020. Pterional craniotomy and transsylvian approach were used in all cases. Aneurysm clipping was performed in 230 cases, revascularization - 27, trapping without bypass - 17, reinforcement - in 11 cases. Computed tomography within 1-3 days after surgery recognized venous cerebral disorders as heterogeneous foci of abnormal brain density with unclear boundaries. These foci were crescent-shaped as a rule and located in deep and basal parts of the frontal lobes.

Results: Venous abnormalities occurred in 76 (26.7%) patients. Thirty-five (12.3%) patients had mild venous edema of the frontal lobe alone. In 35 (12.3%) patients, we found moderate disorders with focus in the frontal lobe and compression of anterior horn of the left lateral ventricle with or without hemorrhagic imbibition. Severe disorders occurred in 6 (2.1%) patients with lesion extending to the frontal, insular and temporal lobes. These lesions were accompanied by hemorrhagic imbibition, and lateral dislocation exceeded 5 mm.

Conclusion: Careful dissection of veins in Sylvian fissure with preservation of bridging veins is likely to reduce the risk of this complication. Cauterization of a large vein in Sylvian fissure should be followed by careful hemostasis within frontal or temporal cortex. Bleeding and cortical tension can indicate intracerebral hematoma whose likelihood is higher in patients with venous cerebral disorders.