Electromyography and A Review of the Literature Provide Insights into the Role of Sacral Perineural Cysts in Unexplained Chronic Pelvic, Perineal and Leg Pain Syndromes

Objective: The clinical entity “Symptomatic Tarlov Cysts” is a highly under reported condition. We aimed to perform an electrophysiologic evaluation in patients with Tarlov cysts to determine whether the cysts create electrical abnormalities that could translate into clinical symptoms. The findings are correlated with the data currently available in the literature. Methods: Thirty patients with unexplained pelvic, sacral, perineal and/or leg pain who harbored small and/or large Tarlov cysts were selected at an outpatient clinic for physical medicine in musculoskeletal disorders. An MRI of the lumbosacral spine of each patient was reviewed. An experienced physiatrist acquired information related to pain and paresthesia in addition to bladder, bowel and sphincter symptoms. An expert electrophysiologist performed nerve conduction and electromyography studies on the patient’s legs and the pelvic floor. A review of the case reports on Tarlov cysts was performed. The symptoms of the patients in the study were compared with the symptoms reported in reviews and case reports. Results: In all cases, the presence of Tarlov cysts was associated with sensory neuron symptoms, such as pain and paresthesia, and with bladder, bowel, sexual, and/or sphincter complaints. In all cases, electromyography documented axonal damage in multiple lumbar and sacral nerve root myotomes. Conclusion: Symptomatic Tarlov cysts clinically and electrophysiologically represent a progressive chronic cauda equine syndrome. In patients with intractable sacral, perineal, pelvic or leg pain, symptomatic Tarlov cysts should be included in the differential diagnosis.