Case Report Sylvian arachnoid cyst typing and neuroendoscopic fistula surgery treatment

Objective: To propose a new typing method for sylvian arachnoid cysts (SACs) and to provide a basis for the choice of surgical approaches of SACs. Methods: 34 cases of SACs were divided into 3 types: I type. SACs medial cyst wall was located in the outer 1/3 of sylvian fissure; type II. SACs medial cyst wall was located in median 1/3 of sylvian fissure; III type. Type I and Type II accepted neuroendoscope cyst-sylvian fissure fistula; type III accepted neuroendoscope cyst-fistulization cistern. Results: The mean follow-up time was 20.2 months; SACs volume reduction rate, remission rate and the incidence of subdural effusion or hematoma were respectively 68%, 38% and 12% (Table 1). The surgery efficacy for type III SACs (postoperative volume reduction rate and remission rate) was superior to type I and type II (P < 0.05); and the subdural effusion or hematoma incidence rate of type III was lower than Type I and type II (P < 0.05); Conclusion: Neuroendoscope cyst-fistulization cistern should be the first choice of Type III SACs; the best surgical approach for Type I and Type II SACs needs further study; the poor effect of cystfistulization may be related to the poor development of ipsilateral sylvian fissure.