Cauda equina syndrome in ankylosing spondylitis: successful treatment with lumboperitoneal shunting

Retrospective study.

To assess outcomes after lumboperitoneal shunting for CES with dural sac dilation and multiple arachnoid diverticula in patients with long-standing AS.

Cauda equina syndrome (CES) is a rare complication of long-standing ankylosing spondylitis (AS). Neurologic symptoms occur insidiously and have a poor prognosis without effective treatment.

We retrospectively studied cases seen between 1997 and 2009 at our university-hospital rheumatology department.

We identified 9 patients with AS and dural sac dilation (mean age: 64, range: 38-75), of whom 8 experienced CES 29.1 years on average (range: 10-51) after AS onset. Presenting symptoms were urinary abnormalities (n = 4), sensory abnormalities (n = 6), or radicular or low back pain (n = 4). The symptoms worsened progressively, with mild (n = 3) to severe (n = 1) motor deficiency, sphincter dysfunction (urinary [n = 6] and/or anal [n = 4] sphincter), and impotence (n = 3). Magnetic resonance imaging showed dural sac dilation (n = 9), multiple lumbar arachnoid diverticula (n = 6), erosions of the laminae and spinous processes (n = 6), and nerve-root tethering (n = 6) with adhesion to the dura mater and vertebrae (n = 7). Cerebrospinal fluid (CSF) flow study by magnetic resonance imaging was performed in 2 patients and showed communication of the diverticula with the CSF. Lumboperitoneal shunting, performed in 5 patients, was followed by improvements in sensation (n = 4), urinary symptoms (n = 2), anal continence (n = 3), and pain. Full recovery of muscle strength was noted in 3 patients. Improvements persisted after a mean of 49 months (range: 18-96).

Lumboperitoneal shunting induced substantial improvements in all 5 patients treated with this procedure. This result suggests that AS-related CES may be due to chronic arachnoiditis and dural fibrosis leading to diminished CSF resorption with dural sac dilation and diverticula formation.