Surgical treatment of distal anterior cerebral artery aneurysms with horizontal head position.

OBJECTIVE: In the surgery for a distal anterior cerebral aneurysm which is applied with a vertical head position, the dome of the aneurysm makes it difficult the expose the neck and the proximal artery. This study was performed to evaluate the applicability of the alternative contralateral interhemispheric approach with a horizontal head position for clipping these aneurysms. METHOD: The head of the patient was placed in the horizontal position such that the aneurysm side remained at the top and then tilted 45 degrees superiorly. On the contralateral side, the craniotomy, interhemispheric dissection and clipping were performed in 12 patients with 13 aneurysms. RESULTS: All aneurysms were clipped successfully. Problems in the standard supine position such as the obstruction of the access to the aneurysm neck and the proximal artery by the dome were not encountered. Vasospasm developed in 4 patients and akinetic mutism in 1 patient; postoperative convulsion due to an inadvertent cortical venous injury in one patient resolved with medical treatment. Hydrocephalus developed in 2 patients; one patient needed placement of a ventriculoperitoneal shunt while the other responded to occasional lumbar punctures. Mortality or permanent morbidity did not occur. CONCLUSION: The horizontal head position may be an alternative for circumventing difficulties posed by the location of distal anterior cerebral artery aneurysms.

Transbasal approaches: surgical details, pitfalls and avoidances.

Lesions involving the anterior skull base and sphenoclival region are difficult surgical problems. This paper presents surgical details, pitfalls, avoidances and our experiences in the surgical treatment of lesions of the anterior skull base using neuronavigation. Between 1999 and 2003, 33 patients with pathology of the anterior skull base were operated on via the traditional transbasal and the extended transbasal approach. A passive-marker-based neuronavigation system has been used for intraoperative image guidance since April 2000. The patients consisted of 11 men and 22 women. Their ages ranged from 3 to 76 years, with a mean of 41 years. The lesions for which the approach was used included 9 cerebrospinal fluid (CSF) fistulae and 24 neoplastic lesions including meningioma (16 cases), metastasis (3 cases), chordoma (3 cases), plasmacytoma (1 case), and osteoma (1 case). Gross total removal of the tumors was accomplished in 22 out of 24 patients with tumor (91.6%). Postoperative complications include CSF leakage (2 cases), infection (2 cases) and transient impaired vision (1 case). One patient (3%) died postoperatively from hypothalamic dysfunction after removal of a benign tumor extending to the anterior third ventricle. Despite the incidence of postoperative infection and the high rate of CSF leakage and death, it is possible to obtain long-term survival for patients with tumors previously considered challenging and difficult surgical problems.