The Supracerebellar Transtentorial Approach for Treatment of Vascular Lesions of the Medial Temporo-occipital Region

Background The supracerebellar transtentorial approach to the inferior occipital lobe, posterior medial temporal lobe, and tentorial incisura via a suboccipital craniotomy provides an adequate surgical corridor to access lesions in these areas. By using this approach, the need of retraction of the occipital lobe and the transcortical route to deep located lesions is avoided. The sitting position provides a gravitational retraction of the cerebellum and a wider supracerebellar corridor to approach deep located pathologies.

Objective The aim of this study is to present the implementation of this approach to treat deep located vascular lesions in two cases.

Methods We identified four cases (two males, two females, mean age 50 years old) treated with this approach in our institution: three patients with cavernomas, two at the parahippocampal gyrus and one at the left lingual gyrus and one patient with right P3 segment dissecting aneurysm. All the cavernomas patients were presented with seizures and the patient with the dissecting aneurysm was presented with mesial temporal hemorrhage. For all cases, a supracerebellar transtentorial approach through suboccipital craniotomy at the sitting position was used. Retraction of the temporal and the occipital lobe was avoided and the siting position offered the advantage of gravitational retraction of the cerebellum. No surgical complication was encountered. Early postoperative MRI revealed complete resection of the cavernomas. The P3 segment of the PCA was identified and the aneurysm was recognized along with three perforating vessels originating from the aneurysm walls. Distal clipping of the P3 vessel was performed with the aim to preserve the perforators' flow and the expectation of gradually aneurysm thrombosis. Postoperative angiogram revealed significant decrease in size of the aneurysm. Repeat angiogram 6 weeks after showed significant regrowth of the aneurysm which was managed endovascularly. Postprocedural the patient developed left side body and face numbness which gradually resolved.

Results In both cases, the supracerebellar transtentorial approach via suboccipital craniotomy was adequate in dealing with vascular pathologies of the inferior occipital lobe and tentorial incisura. The major advantages of this approach were the avoidance of brain retraction and the transcortical route. The sitting position added in this approach the advantage of gravitational retraction of the cerebellum creating a wider supracerebellar corridor.

Conclusion The supracerebellar transtentorial approach via suboccipital craniotomy for vascular lesions of the deep located midline structures represents an adequate route with the major advantages of avoiding brain retraction and transcortical dissection.