Avaliação do acesso supratentorial infraoccipital no tratamento das lesões do espaço incisural posterior: estudo anatômico e clínico

Abstract

An anatomical and clinical study was performed to evaluate the surgical feasibility of the supratentorial infraoccipital approach (SIA) to treat lesions in the posterior incisural space (PIS). This space is located in the postero-lateral area of the quadrigeminal plate, below the splenium of corpus callosum, envolving the pulvinar of thalamus, postero-medial part of the parahipocampal gyrus and the isthmus of cingulate gyrus. Five cadaveric specimens, ten sides, were used for the anatomical study at the Federal University of Minas Gerais neurosurgery laboratory. A mathematical evaluation was done, measuring the distance from the torcula to the splenium of corpus callosum, pineal gland, calcarine artery, isthmus of cingulate gyrus, quadrigeminal plate, pulvinar of thalamus and the falcotentorial junction. The distance between the occipital pole and the falx cerebri, due to the occipital lobe retraction, was also measured. The exposure angle to reach the PIS was calculated. A retrospective analysis of twenty-two patients harboring tumors or arteriovenous malformations located at the PIS, operated by SIA, was done. There were 15 patients with tumors (astrocytomas, meningiomas and metastatic lesion) and seven with vascular lesions. Total resection was achieved in all five arteriovenous malformations patients as well as in six out of fifteen tumor patients. Nine patients had a partial tumor resection, and two a satisfactory aneurism exclusion. The anatomical and clinical results showed a good surgical feasibility when using the SIA to treat lesion at the PIS, with an exposing angle of 37.3 degrees of the target area, a surgical field deepness of approximately 50 mm, allowing good amount of lesion resection.