The Endoscopic Supracerebellar Infratentorial Approach in the Sitting Position: A Safe and Effective Update to a Traditional Approach

Background: The supracerebellar infratentorial (SCIT) approach has been a workhorse of the skull base neurosurgeon for pineal region lesions. Historically, this approach has been performed using the surgical microscope with the patient in the prone/Concorde or the sitting position. Herein, we present a case series demonstrating the safety and efficacy of the endoscopic supracerebellar infratentorial approach in the sitting position, and describe our reconstruction protocol involving the use of inlay collagen sponge grafts to minimize CSF leaks and related complications.

Methods: A retrospective analysis of all surgeries performed via the supracerebellar infratentorial approach in the sitting position at our institution was performed. All patients were monitored for air embolism with pre-cordial Doppler and in many cases transesophageal echocardiogram (TEE). Patients with preoperative right-to-left atrial shunting were performed in prone position (not part of this study). A small, unilateral 2 × 3 cm craniotomy was performed in all cases. Dural closure was performed with an inlay and onlay collagen sponge and interrupted sutures (regardless of 3rd ventricular entry). Patient demographics, pathology, use of endoscopy, resection rate for tumor cases, (biopsy vs. subtotal resection [STR] vs. gross total resection [GTR]), and complications were analyzed. The resection rates between the different types of procedures were compared. All procedures were performed by a team with extensive experience in endoscopy.

Results: A total of 27 patients underwent operations using the sitting position supracerebellar infratentorial (SCIT) approach. Of these operations, 3 were performed fully microscopic, 9 were endoscopic-assisted, and 15 were fully endoscopic. Pathologies included: glioma (5, 18.5%), metastatic tumors (2, 7.4%), pineal tumors or cysts (with rectal symptoms or hydrocephalus: 150, 55.5%), midbrain cyst (1, 3.7%), and cavernous malformation (1, 3.7%). One procedure was performed for trochlear nerve decompression, and two were for biopsies of inflammatory processes. Complications arose in 5 (18.5%) cases: One patient developed postoperative hydrocephalus, one patient with known CAD suffered a postoperative myocardial infarction, two cases were complicated by air embolism, with only one case needing to be aborted (both recovered well perioperatively), and another case was aborted due to loss of bilateral lower extremity somatosensory evoked potentials caused by malpositioning. For tumor cases in which maximal safe resection was the goal of surgery, 4 cases (40%) achieved GTR and 6 cases (60%) achieved STR. There were no postoperative cerebrospinal fluid leaks or pseudomeningocoeles.

Discussion: This small series suggests that the endoscopic supracerebellar infratentorial approach with the patient in the sitting position can be a safe and effective approach for reaching the pineal region for a variety of different pathologies. The endoscope allows for improved visualization, resulting in smaller craniotomies and offering improved ergonomics to the surgeon. The traditional watertight closure was not necessary in these patients given the small exposure and inlay collagen sponge grafts.

Publication History

Article published online:
01 February 2023