What percentage of surgically clipped intracranial aneurysms have residualnecks?

OBJECTIVE: To determine the angiographically proven rate and persistence of occlusion of intracranial aneurysms after surgical clipping as reported in the literature. This should establish a basis for comparing surgery with n ew endovascular methods of treatment. METHODS: We reviewed the literature published during the period from 1979 t hrough 1999, dividing the articles into two groups. The first group of arti cles reported patients undergoing surgical treatment with immediate postope rative angiography. The second group of articles documented symptomatic rec urrence or regrowth of aneurysms that were surgically treated previously. T he data from these articles are presented for analysis. RESULTS: During the period 1979 to 1999, six series of patients undergoing surgical treatment of aneurysms with immediate postoperative angiography we re reported. These reported series comprised a total of 1397 patients, of w hom 1370 underwent postoperative angiography demonstrating 1569 clipped ane urysms. Residual filling was found in 82 aneurysms (5.2%) on postoperative angiography. Of the 1370 patients, only 124 patients with 169 aneurysms wer e reported to have had any long-term angiographic follow-up. The second gro up consisted of 226 patients representing six reported groups of patients, who either presented up to 24 years after aneurysm clipping with recurrent symptoms of hemorrhage or mass effect, or had important findings on intraop erative and postoperative angiograms. CONCLUSION: The lack of information regarding both the frequency of residua l filling or regrowth and long-term angiographic follow-up of patients with surgically treated aneurysms makes meaningful comparison between surgical treatments and new treatment methods for intracranial aneurysms difficult o r impossible. Detailed analysis with high-quality angiography should be per formed to determine the success of surgical treatment.