Refinement of the Infratentorial Supracerebellar Approach to Pineal Lesions

Although the infratentorial supracerebellar approach (ITSCA) has been improved, refinements are still needed. We used ITSCA in seven patients with pineal lesions and evaluated our experience for the refinement of ITSCA.

The patient was placed prone and brought to the far left side of the table with the patient's thorax elevated 10 degrees. The head was tilted 30 degrees toward the right side. The degree of flexion of the neck was tailored to the extent of the slant of the tentorium of each patient so that the tentorium was at about a 60-degree angle to the horizontal. This tailored Concorde position enabled the surgeon to sit behind the patient's left shoulder and operate as comfortably as during a trans-sphenoidal approach. A midline vertical skin incision was sufficient for a bilateral suboccipital craniotomy. Removal of bone above the transverse sinuses and torcula was not necessary because it would not allow additional upward retraction of the sinus complex. Removal of an adequate amount of CSF from the cisterna magna was essential in the first intradural procedure, which made exposure of supracerebellar-infratentorial corridor easy and safe, despite negation of gravity-assisted retraction. Pineal gland tumors were routinely bisected during internal decompression until the third ventricle was entered. The exposed ventricular walls provided a reference point for the lateral margin of tumor and as to the depth of tumor and thus ensured safe dissection between thalamus and tumor.

Following the principles of surgery for brain tumor, which are proper positioning, obtaining a slack brain, and dissection around the internally decompressed tumor based on anatomy, is a prerequisite for the refinement of ITSCA.