Definite indications for the treatment of unruptured cerebral aneurysm (uAN) are very difficult to establish because the risk of rupture for any individual aneurysm still cannot be estimated. Furthermore, the criteria for evaluation of the prognosis and potential complications remain unclear, so no risk-benefit analysis can be performed. Recently, prevention of adverse effects to improve patient safety and satisfaction have become more important in the field of neurosurgery. We analyzed the occurrence and nature of adverse effects in 156 consecutive patients treated for uAN in our institute.
The patients were treated with endovascular coil embolization for mainly paraclinoid or basilar apex aneurysms in 17 men and 38 women aged 35-81 years (mean 62.1±10.0 years) or surgical clipping for other aneurysms in 23 men and 78 women aged 35-77 years (mean 58.4±9.9 years). Anterior cerebral, anterior communicating, and middle cerebral artery aneurysms were significantly more common in the clipping group, whereas internal carotid and vertebrobasilar artery aneurysms were significantly more common in the coil group.
Selection and treatment of uAN by our team showed generally good results in the short term. However, long-term observation to detect such complications as recurrence is required. Serious adverse events occurred in 17 of all 156 patients (10.9%), including mortality in 1 patient (0.6%), major morbidity (less than modified Rankin scale score 2) in 1 patient (0.6%), minor morbidity in 3 patients (1.9%), and transient neurological deficits in 12 patients (7.7%). The incidence of serious adverse events was similar in the coil and clipping groups, but all events including minor, transient, and other adverse events were significantly (p<0.05) more common in the clipping group.
No permanent motor deficit occurred in the clipping group, and intraoperative use of the mirror, endoscope, Doppler flowmeter, fluorescence angiography, and electrophysiological monitoring including motor evoked potential (MEP) were considered to be very important to avoid ischemic complications. Unexpectedly common postoperative seizures may indicate that adequate saturation of anticonvulsant agent is necessary before surgery. The many problems caused by craniotomy should be recognized as avoidable complications. Unfortunately, serious postoperative neurological deficits were also frequently encountered. Endovascular coil embolization provides a complementary treatment to surgical clipping because no re-treatment of coil embolization or clipping was required for problems such as perforator injury surrounding the basilar apex or optic nerve damage. However, 1 patient died of vessel laceration during neck plasty, so improvement of procedures is essential.