Introduction: Tarlov or perineural cysts (TC) develop between peri-and endoneurium of spinal nerve root at the junction of nerve root and dorsal root ganglion. They affect between 4.6 and 9% of adult population and are symptomatic in approximately 1%. Common presentations are lower back pain, sciatica, or bowel and bladder dysfunction. It is generally agreed that asymptomatic cysts should be monitored. However, the optimal treatment of the symptomatic Tarlov cysts remains controversial. Neurosurgical treatment includes decompressive laminectomy, cyst excision and microsurgical cyst fenestration and imbrication. CT guided aspiration, though less invasive, have higher recurrence rate. We report a case of Tarlov cyst treated with transforaminal steroid injection with good short term symptomatic relief.

Case Description: 59-year old female presented with a 6 year history of progressive worsening low back pain with radiation to the left thigh. Conservative treatment including lumbar epidural steroid injections in the past did not improve the pain and she rated her pain as 5/10 on numeric rating scale (NRS). Neurological examination was intact. MRI scan showed nerve root sleeve cyst compressing on the left L3 dorsal root ganglion. To relieve her symptoms, left L3 and L4 selective nerve root block with 40 mg Depomedrol and 0.25% bupivacaine was performed under fluoroscopic guidance. Complete symptomatic relief lasting 3 weeks was obtained, which was followed by repeat L3 SNRB with longer lasting relief (3 months). The next step is to consider pulsed radiofrequency neuromodulation if pain returns.

Discussion: Tarlov cysts are usually asymptomatic but may cause compressive radiculopathy. The treatment of symptomatic Tarlov cysts remains controversial. This is the first report to document short term symptomatic relief from compressive radiculopathy associated with Tarlov cyst with selective nerve root blocks. This report also provide basis to study role of pulse radiofrequency in the management of Tarlov cysts.