Endoscopic cystoventriculostomy for treatment of paraxial arachnoid cysts

Object. The optimal therapy of arachnoid cysts is controversial. In symptomatic extraventricular arachnoid cysts, fenestration into the basal cisterns is the gold standard. If this is not feasible, shunt placement is frequently per-formed although another endoscopic option is available. Methods. Between March 1997 and June 2006, 12 endoscopic cystoventriculostomies were performed for the treatment of arachnoid cysts in I I patients (4 male and 7 female patients, mean age 52 years [range 14-71 years]). All patients were prospectively followed up. Results. In 11 cases, the arachnoid cysts were frontotemporoparietal and fenestration was performed into the lateral ventricle. In I case, the arachnoid cyst was located in the cerebellum and the cyst was fenestrated into the fourth ventricle. Neuronavigational guidance was used in all but I case. Endoscopic cystoventriculostomy was performed in all cases without complications. No stents were placed. The mean surgical time was 71 minutes (range 30-110 minutes). The mean follow-up period was 42.7 months (range 19-96 months) per surgical case and 48.8 months (range 19-127 months) per patient. Symptoms improved after I I of the 12 procedures; 7 of the I I patients became symptom-free and the others had only mild residual symptoms. The patient who did not experience clinical improvement suffered from depression and demonstrated a significant. decrease of the cyst size on the postoperative MR imaging. After I I of 12 procedures, a decrease in cyst size was observed. In I case, a subdural hematoma developed; it required surgical treatment 3 months after surgery. In another case, reclosure of the stoma required repeated endoscopic cystoventriculostomy more than 7 years after the initial procedure. Conclusions. Overall, endoscopic cystoventriculostomy represents a useful treatment option for patients with paraxial arachnoid cysts in whom a standard cystocisternotomy is not feasible. Based on the results in this case series, stent placement appears not to be required. Despite the long mean follow-up of almost 4 years, however, a longer follow-up period seems to be required before definite conclusions can be drawn. (DOI: 10.3171/2008.7.JNS0841)