Surgical corridor formation by minimally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach in pineal region tumor surgery: A review of 11 cases

Introduction: The pineal region is a hard-to-reach part of the brain. There is no unequivocal opinion on the choice of a surgical approach to the pineal region. The surgical approaches described differ in both trajectory (infra-and supratentorial, interhemispheric) and size of craniotomy. They have advantages and disadvantages. The mini-mally invasive lateral occipital infracortical supra-/transtentorial (OICST) approach we have described has all the advantages of the standard supratentorial approach and minimizes its disadvantages, namely, compression and contusion of the occipital lobe. The minimally invasive craniotomy and small surgical corridor facilitate that.Methods: We describe 11 consecutive patients with various pineal region tumors (7 cases of pineal cysts, 2 cases of pinealocytoma, 1 case of medulloblastoma, and 1 case of meningioma) who were operated on in our hospital using the lateral OICST approach. Preoperative planning was performed using Surgical Theater (R). The surgical corridor was formed using a retractor made from half of a syringe shortened according to the length of the surgical corridor. Preoperative lumbar drain was used.Results: The pineal region tumors were completely resected in all cases. The mean craniotomy size was 2.22 x 1.79 cm. No long-term neurological deficits were reported.Conclusions: The use of semicircular retractors and intraoperative CSF drainage via a lumbar drain allows to form a small surgical corridor to the pineal region via minimally invasive craniotomy. This reduces traction and traumatization of the occipital lobe, as well as minimizes intra-and postoperative risks.