Comparing Surgical Treatment Options for Intracranial Arachnoid Cysts; Radiological, Clinical and Histopathological Outcomes of the Operated Patients

Aim: This study was designed to examine patients who underwent surgery for arachnoid cysts and compare surgical treatment options in terms of clinical, radiological and histopathological outcomes. Methods: Data obtained from 47 patients who underwent surgery for arachnoid cysts at 3 neurosurgery institutions between November 2002 and January 2020 were retrospectively reviewed. As the surgical interventions, two methods were performed; cyst fenestration with craniotomy, and cystoperitoneal shunt. Results: The mean age of the patients was 12.7 ± 11.3 years. Among them, 18 (38.3%) were female and 29 (61.7%) were male. 40 were pediatric and 7 were adult patients. In the study group, 32 patients (68%) underwent fenestration with craniotomy, while 15 patients (32%) underwent cystoperitoneal shunt application. The mean reduction rates of the cyst volume were determined as 51.4%. When comparing the surgeries performed, no statistically significant difference was found between the reduction rates (p>0.05). The group with the highest reduction rates was detected as convexity cysts treated with fenestration with a rate of 73.9%. In the postoperative period, the symptoms of 29 patients (62%) completely resolved, while the symptoms of 14 patients (30%) improved. Symptoms did not change in 3 patients (6%), and worsening was observed in 1 patient (2%). When comparing the surgeries performed, the rate of complete resolution of symptoms was found to be statistically significantly higher in the fenestration group (p=0.01). Postoperative cyst volumes were found higher in the patients with edema positivity (p=0.031) and thickening of basal lamina negativity (p=0.046). Preoperative mass effect was found statistically significant in the patients with edema positivity (p=0.006) and thickening of basal lamina negativity (p=0.013). Postoperative mass effect reduction was also found statistically significant in the patients with edema positivity (p=0.024) and thickening of basal lamina negativity (p=0.002). Conclusions: The present study revealed that fenestration with craniotomy seems to be a favorable technique as the first step in the treatment of arachnoid cysts. The rate of complete resolution of symptoms was higher in the fenestration group and complication rates were higher in the cystoperitoneal shunt group. However, we think that the patients with coexistence of arachnoid cyst and hydrocephalus should be treated with cystoperitoneal shunt application. We also found that the membrane thickness of arachnoid cysts and the amount of collagen increases as the patients’ age increases and tissue edema increases in younger patients. Preoperative mass effect, and postoperative reduction in mass effect correlated positively with tissue edema and negatively with basal lamina thickness.