Pain
Daniel De Simon, MD, MBA
Resident Physician
Atrium Health Carolinas Rehabilitation
Charlotte, North Carolina, United States
Michael Dove, MD
Physician
Atrium Health
Charlotte, North Carolina, United States
Left S1 nerve root compression secondary to foraminal perineural Tarlov cysts.
Case Description:
A 37-year-old woman presented with six months of low back pain beginning after a cycling class, localized to the left upper buttock with numbness/tingling in the plantar left foot. Examination suggested left S1 radiculopathy. Lumbar MRI showed prominent perineural (Tarlov) cysts in the bilateral S1–S2 foramina with mild mass effect on the nerve root. Symptoms progressed despite oral analgesics and physical therapy. Electromyography and pelvic MRI were unremarkable, and neurosurgery did not recommend operation. A left L5–S1 transforaminal epidural steroid injection (TFESI) produced approximately 80% pain relief for two months.
Discussions:
Tarlov (perineural) cysts are often incidental; causality remains controversial due to variable presentations, inconsistent diagnostic criteria, and mixed treatment outcomes. In this case, clinical–radiographic concordance supports a causal role, while normal EMG highlights how electrodiagnostic testing may be insensitive in intermittent or mild root compression. A stepwise approach prioritizing conservative care followed by minimally invasive options can provide relief while avoiding the risks and uncertain benefit of surgery. Interventions including targeted TFESI, and in selected cases percutaneous cyst aspiration with or without fibrin sealant, seek to reduce cyst-related pressure/inflammation and can serve both therapeutic and diagnostic purposes. Surgical decompression is generally reserved for refractory, clearly concordant cases given variable efficacy and complication risk.
Conclusions:
This case of left S1 radiculopathy attributed to sacral Tarlov cysts illustrates the value of careful clinical–imaging correlation and staged, minimally invasive management strategy. Targeted TFESI provided meaningful but temporary relief, supporting a pressure/inflammatory mechanism in the absence of alternative findings on EMG or pelvic MRI. Interventional spine procedures may play a pivotal role in managing symptomatic Tarlov cysts, and further prospective research is needed to standardize diagnostic criteria, optimize patient selection, and compare the effectiveness of non-surgical and surgical treatments.
