The telovelar approach for surgery of the fourth ventricle
Grigoryan Yu. A., Sitnikov A. R.
Keywords: telovelar approach, fourth ventricle
Objectives:The dissection of cerebellomedullary fissure provides approach for exposure of the fourth ventricle without vermian splitting. The purpose of this study is to describe the variants of the telovelar approach and the results in 26 patients, operated by the unilateral telovelar approach.
Materials and methods: 26 patients were operated via telovelar approach. The patients have had various pathologies of the brainstem (8 cases) and the fourth ventricle (18 cases).
Results: The mean age of patients was 41.5 years (between 17 and 66 years). There were 11 females and 15 males. Most of the lesions were ependymomas, epidermoids, choroid plexus papillomas and cavernomas. A variant of unilateral telovelar approach – tonsillomedullar (6 cases), tonsillouvular (9 cases) and combined (11 cases) – was suited for every patient. Total removal of the lesion was achieved in all but two cases. There was only one lethal outcome not related with surgery due to severe co-morbid diseases in 2 months after the operation. The complication included two cases of meningitis, one case of intraventricular haemorrhage, required a surgery, and one case of CSF leakage, successfully treated with external lumbar drainage. Twelve patients developed mild neurological complications including unilateral pyramid signs in 6 cases, sensation disturbance in 3 patients and ataxia in 8 cases in various combination were reversible.
CONCLUSION: tonsillouvular approach is more preferable for the centrally located tumours from aqueduct to obex of the fourth ventricle without significant lateral spreading. The tonsillomedullar variant is better for tumours of the lower part of the fourth ventricle with a lateral spreading towards the foramen of Luschka. The unilateral telovelar approach (tonsillouvular and tonsillomedullar variants) must be used in cases of large centrally located tumors of the fourth ventricle with significant spreading in the lateral recess and the cerebellopontine angle.