Objectives Sacral Tarlov cysts (TC) are frequent incidental findings on spinal MRI. Controversy remains regarding their ability to cause nerve root compression. Pelvic neurophysiological and urodynamics testing provides information about sacral nerve root involvement.

Design Case series

Subjects Patients with MRI evidence of sacral (S1, 2 or 3) TC seen in the Uro-neurology Department between 2011 and 2018.

Methods Clinical, neurophysiological and urodynamics data were reviewed.

Results 13 patients (9 females, mean age54/SD13.1) were included. Symptoms were urgency/incontinence (n=8), hesitancy/urinary retention (n=7), bowel complaints (n=4), sexual complaints (n=3), back pain (n=5), genital/pelvic pain (n=6), genital numbness (n=5), impaired sensation of bladder fullness (n=2), lower limb (LL) pain/hypoesthesia (n=6), LL weakness (n=2). The following neurophysiological abnormalities were seen: anal sphincter EMG (n=10) evidence for reinnervation (n=8), pudendal sensory evoked potentials (SEPs) (n=6) absent response (n=1), S2 and S3 dermatomal SEPs (n=6) absent response (n=2), sympathetic skin response (n=6) absent response (n=3). Findings in cystometry (n=5) were: detrusor underactivity (n=2), detrusor after-contraction (n=1), equivocal obstructed voiding (n=1) and reduced bladder compliance (n=1).

Conclusions Abnormal results in urodynamics and pelvic neurophysiology suggest involvement of the somatic and autonomic sacral innervation. Further studies are required to explore any association between structural changes on MRI and functional changes in urodynamics and neurophysiology.