TWO YEAR CLINICAL RESULTS OF X STOP INTERSPINOUS DECOMPRESSION DEVICE IN THE MANAGEMENT OF SYMPTOMATIC LUMBAR CANAL STENOSIS

Abstract

Aim: To assess the clinical effectiveness of X stop interspinous decompression device in patients with neurogenic claudication due to lumbar canal stenosis at 24 months post surgery.

Design: Prospective Observational Study of 57 patients with X stop procedure.

Methods: Fifty-seven patients with unilateral or bilateral leg pain due to lumbar canal stenosis, who had significant relief from sitting or flexing the lumbar spine, were treated with X stop.

Clinical outcome was assessed by Zurich claudication questionnaire (ZCQ), visual analogue score (VAS), Oswestery disability index (ODI) and SF36 questionnaires preoperatively and at 2 years. ZCQ has three components- symptom severity, physical function and patient satisfaction. ZCQ is considered the most precise, reliable and condition specific questionnaire for lumbar canal stenosis.

Out of 57 patients, 2 died due to unrelated causes, 3 withdrew from study and 3 had the device removed within 2 years. Forty-five, 44, 42 and 48 completed ZCQ, ODI, SF-36 and VAS respectively at 24 months.

Results: The mean age was 71(53–94) and M: F ratio 29:28. X stop device was inserted at single level in 32 (56%) and double levels in 25(44%) patients. In single level cases, 72% reported improvement in symptom severity, 65% in physical function, 68% were satisfied with the procedure, and overall 55% made a clinically significant improvement at 24 months. In double level cases, the figures were 62%, 68%, 78% and 40% respectively. The threshold for changes in symptom severity was 0.46, physical function was 0.42 and patient satisfaction 2.42. Overall clinically significant improvement requires that a patient achieves at least 2 criteria.

The mean ODI improved by 6.5 in single level and 10.8 in double level cases. The SF-36 showed improvement in physical function, role physical, bodily pain and vitality social domain.

Average hospital stay for the procedure was 1.6 days. One patient stayed for 10 days for investigation unrelated to the procedure. There were no major complications.

Conclusions: The results of our study show that the X stop interspinous decompression device remains clinically effective at the end of 2 years. X stop is a relatively less invasive procedure, especially suitable for patients with other co-morbidities, which can be performed as a day case procedure without major complications.