Introduction: The pineal region, often referred to as the posterior incisural space, is located posterior to the midbrain and anterior to the cerebellar vermis. Lesions in this area include primary pineal tumors, vascular malformations and lesions involving the medial temporal lobe and anterior cerebellum. The occipital interhemispheric approach, popularized by Poppen and since revised, is widely used in the resection of pineal region tumors and makes use of the paucity of bridging veins to the superior sagittal sinus at the occipital pole. It also provides a wide working corridor and enables access above the deep draining veins.
Methods: We retrospectively reviewed all cases of occipital interhemispheric approach performed by the senior author, from 2000-2012. We identified 25patients who had undergone the approach for a variety of pathology. We report on the surgical outcome, complications and clinical outcome.
Results: Of the 25 patients identified (28 cases), there were 11 primary pineal tumors, 4 gliomas, 1 metastatic tumor and 9 vascular lesions. Headache was the most common presenting symptom and was seen in 76% of the cases. Other common presenting symptoms included dizziness (36%), ataxia (32%), visual deficits (24%) and memory and cognitive problems (20%). Gross total resection was achieved in 80%. Average follow-up was 15.5months. Two patients had new but transient visual symptoms. There were no post-operative infections, CSF leaks, hemorrhage or venous/arterial infarctions. There were no surgical deaths. 80% of the patients had a Glasgow Outcome Score of 4 or 5.
Conclusions: The occipital interhemispheric approach is safe and efficacious way to approach pineal region tumors. It provides a wider working corridor and access to lesions in the medial temporal lobes and the superior cerebellar vermis. Appropriate patient selection based on extensions of the lesion and deep venous displacement is still tantamount in selecting the suitable approach.
Patient Care: While it is a retrospective series, it would be the largest series of occipital interhemispheric approach reported in the literature, and therefore, it provides a baseline for further research and comparisons in the field.
Learning Objectives: By the conclusion of this session, participants should be able to 1) understand the anatomy of the pineal region, 2) recognize the many indications for the occipital interhemispheric approach and 3) provide an appropriate comparison with other approaches to this region.