Interdisciplinary Neurosurgery (Mar 2023)
How effective is occipital transtentorial approach for pineal region lesions? An assessment of occipital lobe functions & surgical outcome
Abstract
Background and objectives: The occipital transtentorial approach (OT) is a useful surgical approach for the treatment of lesions of the pineal region. Because the approach provides wide operative views of superior cerebellar, splenium, quadrigeminal regions can also be operated using this technique. However it may be associated with complications due to damage to the occipital lobe, which can be caused by brain retraction injury. The study evaluates the effectiveness of the OT approach in terms of surgical outcome with special emphasis on occipital lobe functions which may be affected using this approach. Methodology: Seventeen patients of pineal region lesions were operated by OT approach, and preoperative evaluation of the anatomy of the tentorial angle was performed and its significance was studied. Various occipital lobe functions were evaluated postoperatively and compared with preoperative status. Surgical outcome was evaluated in terms of extent of tumour resection, postoperative occipital lobe functions and modified Rankin scale. Results: The mean angle between the tentorium and occipital surface of cerebellum (tentorial angle) was 62.08 ± 7.17 degrees. The maximum and minimum tentorial angle was 83 and 51 degrees respectively. Out of 13 patients in which the postoperative functional assessment of occipital lobe functions was possible, 2 patients developed homonymous hemianopia (one transient, one permanent). Other functions remain unaffected. Near and gross total resection was possible in 4 (23.5 %) and 8 (47.1 %) patients respectively. The mean modified Rankin scale score was 1.8 indicating slight post-operative disability. Conclusions: Amongst the various occipital lobe functions, the visual field defects are the most common functions affected postoperatively in the occipital transtentorial approach. The OT approach is an appropriate and reasonable approach for the surgical management of pineal region lesions where high resectability rates can be achieved irrespective of the status of anatomical factors like tentorial angle; with slight postoperative morbidity with respect to occipital lobe functions.
