Far lateral approach without occipital condylar resection for intradural ventral/ventrolateral foramen magnum tumors and aneurysms of V4 segment of vertebral artery: Review of surgical results

Abstract

Background: Controversies exist regarding the need and extent of condylar resection for safe surgical management of intradural ventral/ventrolateral foramen magnum (VFM) tumors and aneurysms of V4 segment of vertebral artery (VA) by far lateral approach. This retrospective study was conducted to evaluate the results of basic far lateral approach(retrocondylar approach) without upfront occipital condylar resection.

Methods and results: Twenty one patients underwent surgery via far lateral approach for intradural VFM tumors and aneurysms of V4 segment of VA at Sri Sathya Sai Institute of Higher Medical Sciences during 9 years(2008-2016) study period. Eight patients had VA aneurysms and 13 patients had intradural VFM tumors. After basic far lateral approach(retrocondylar approach), dura was opened and checked if the exposure was adequate for safe surgery. Retrocondylar approach provided adequate exposure for all these lesions and resection of occipital condyle/jugular tubercle was not required in any of these cases. Skeletonization or transposition of VA was not done in any of these cases. Gross total resection of the tumor could be done in 9 patients(9/13-69.2 %) and near total excision (>95 %) in 4 patients (4/13-30.8 %). Seven of the 8 VA aneurysms were successfully clipped. Outcome at a final follow up of 3 months or more was good(mRS<2) in 19 patients(19/21-90.5 %) and poor in 2 patients. Complications included lower cranial nerve deficits [transient-2/21(9.5 %), persisting-2/21(9.5 %)], motor deficits(2/21-9.5%), seventh nerve paresis(1/21-4.8%), sixth nerve paresis(2/21-9.5%) and pseudomeningocele(1/21-4.8%).

Conclusion: Basic far lateral (retrocondylar) approach provides excellent exposure for majority of VFM tumors and aneurysms of V4 segment of VA. Condylar resection(transcondylar approach), drilling of jugular tubercle (transtubercular approach), skeletonization/transposition of VA might not be required for safe surgical management of majority of these lesions.

Keywords: Far lateral approach; Foramen magnum lesion; Retrocondylar approach; Trans tubercular approach; Transcondylar approach.