Midline and far lateral approaches to foramen magnum lesions.

Twenty patients with foramen magnum lesions were operated upon in the last 5 years at Postgraduate Institute of Medical Education and Research, Chandigarh. The common presenting features were quadriparesis, quadriplegia, diminished sensations, neck pain and respiratory insufficiency. The lesions encountered were meningiomas, neurofibromas, posterior inferior cerebellar artery aneurysms, neurenteric cyst and chordoma. Patients with posterior or posterolaterally placed lesions were operated by the midline posterior approach while those with anterior or anterolateral lesions were managed by the far lateral approach. All mass lesions were excised completely and the aneurysms were clipped. Seventeen patients made good neurological recovery while three died. The latter three patients presented very late. The merits of various surgical approaches to the foramen magnum are discussed.

Extreme lateral transcondylar approach to the skull base.

In this study, the authors present their experience of using extreme later transcondylar approach (ELTC) for treating 7 patients with lesions in the anterolateral foramen magnum, upper cervical spine and cerebellopontine angle reaching upto jugular foramen. The tumours included meningiomas, neurofibromas (2 cases each), chondrosarcoma, epidermoid and aneurysmal bone cyst (one case each). The approach was used alone, in combination with retrolabyrinthine presigmoid approach in a patient with lower cranial nerve neurofibroma extending extracranially through the jugular foramen, or in combination with partial C1-C3 laminectomy in two patients with meningiomas situated anterolateral to the cord from the foramen magnum to C3. In two patients with extradural vertebral artery (VA) entrapment by a chondrosarcoma and aneurysmal bone cyst respectively, the vertebral artery was ligated distal to the tumour. The tumours were totally excised in five cases and partially in two. There was no preoperative mortality. The major complications included cerebrospinal fluid leak from the wound (3 cases) and increase in lower cranial nerve paresis (2 cases). At follow up, ranging from 6 months to 2 years, 5 patients showed no tumour recurrence. There was improvement in neurological status. One patient, with a partially excised aneurysmal bone cyst, showed no added deficits or increase in the tumour size. However, there was a massive regrowth in the patient with chondrosarcoma after 6 months. This technique provided a wide surgical exposure with direct visualization of the tumour-anterior cord interface, early proximal control of the VA and preservation of lower cranial nerves.