Successful Surgical Ligation of a Giant Tarlov Cyst at the Cyst Neck Including the Nerve Root: A Case Report.

Perineural cysts are meningeal protrusions at nerve roots that can be asymptomatic but may require surgical intervention. Tarlov cysts, specifically located at sacral nerve roots, lack a consensus on optimal surgical treatment. This case report describes surgical management of a giant Tarlov cyst. A 29-year-old woman with infertility, low back pain, and constipation was found to have an 11 cm giant pelvic cyst originating from the left S3 nerve root. Preoperative imaging and symptoms suggested a perineural cyst. Intraoperative electromyographic monitoring revealed that the S2 nerve root could compensate for S3 function. Consequently, we performed radical ligation of the cyst neck together with the left S3 nerve root. Postoperatively, the patient's sensory disturbance in the posterior left thigh improved. Two months after surgery, the cyst remained regressed, constipation had improved, and the patient showed a favorable outcome. This case demonstrates successful surgical ligation of a giant Tarlov cyst, suggesting that when intraoperative nerve monitoring confirms compensatory nerve root function, radical nerve root ligation can be a viable surgical option.