Hydrostatic pressure mechanism and surgical efficacy of Tarlov cysts.

[BACKGROUND] Tarlov cysts (TCs) are commonly found sacral perineural cysts. Symptomatic TCs are rare, and there is no consensus on optimal treatment. The pathophysiological mechanism of TCs remains unclear. The aim of this study is to investigate the effects of surgical intervention on symptomatic TCs and the development mechanism of TCs.

[METHODS] We retrospectively analyzed the clinical data of 26 patients with symptomatic TCs who underwent surgical treatment in our department between November 2016 and June 2019. Intraoperative manometry was performed in 10 of these patients. Pain relief and clinical outcomes were evaluated statistically.

[RESULTS] Postoperative symptoms improved in 25 patients (96.2%), while one patient (3.8%) showed no improvement. No wound infections or new complications were observed. Patients were followed for 5-49 months (mean: 28.04±12.57 months). There were statistically significant decreases (p<0.05) in the M-JOA low-back pain scores from preoperative (26.32±1.75) to postoperative (14.92±5.95) values, as well as a significant improvement (p<0.05) in the NRS pain scores from preoperative (2.02±1.46) to postoperative (6.23±1.20). Preoperative intracapsular pressure ranged from 3.1 to 12.4mmHg across different positions. Postoperative sacral canal pressure ranged from 0.1 to 0.8mmHg in various positions.

[CONCLUSION] Cyst excision and perineurium reconstruction under a microscope is an effective and safe method for treating sacral radicular cysts.