Microneurocirugía de quistes y tumores de la región pineal: técnicas, indicaciones y resultados a largo plazo

ABSTRACT

Immediate and long-term outcomes after treating patients with pineal region cysts and tumors are not well established. The centralized Finnish health care and the Finnish population register offer excellent registry systems for long-term retrospective studies. This thesis aimed to investigate the long-term outcomes of surgically treated pineal region cysts and tumors based on three elements developed in Helsinki University Hospital along the study period: a. the complete microsurgical resection; b. the praying sitting
position, and c. the paramedian supracerebellar infratentorial approach.

Pineal region neoplasms are well-recognized entities. However, quantitative parameters to differentiate normal anatomical variations from pathological benign pineal cysts are currently inexistent. Thus, we studied the correlation between the pineal cyst size and the clinical severity of the patients.

This thesis presents one of the most comprehensive long-term studies of surgically treated pineal region cysts and tumors. The long-term survival, clinical, and radiological outcomes present here were superior to those reported in the literature. Each publication includes a subgroup of the 147 consecutive surgically treated patients with pineal region lesions operated in the Department of Neurosurgery of Helsinki University Hospital between 1997 and 2015. We found a direct correlation between the pineal cyst
diameters and the severity of the disease. Thus, a surgically treated pineal cyst appeared a clinically progressive disease with average cyst diameters running between 15mm and 25mm and hydrocephalus at the last stage.

The short- and long-term postoperative functional status of the pineal cyst patients improved after surgery in all except one patient. 97% of the pineal cyst patients achieved complete cyst removal without noticed recurrence nor mortality at 149 ± 62 months. The disease mortality of the patients with surgically treated pineal region tumors reached 18% at 125 ± 105 months of follow-up. Overall, patients with complete tumor removal had superior disease survival and tumor-free imaging outcomes compared to those with
incomplete resected neoplasms. However, the extent of resection did not appear to influence the survival rates of diffuse glioma patients.

Venous air embolism was present in 35% of patients undergoing praying sitting position for pineal region surgery. Severe venous air embolism was absent in the studied series. Among all pre- and intraoperative variables, the only venous injury was associated with venous air embolism. Thus, following proper anesthetic and surgical considerations, the sitting praying position in pineal region surgery does not harbor high risks for severe venous air embolism. Lately, the developed paramedian approach resulted in more functional and safer modification of the conventional midline supracerebellar approach. The effectiveness of the two approaches remained similar in terms of clinical, radiological, and survival outcomes.