A PROSPECTIVE COMPARATIVE COHORT STUDY OF SINGLE LEVEL LUMBAR DECOMPRESSION AND AN INTERSPINOUS DISTRACTION DEVICE

Abstract

Aim: To compare the outcomes and complications of an interspinous distraction device and decompression for single level spinal stenosis in the lumbar spine

Study type: Prospective comparative cohort audit of a new procedure.

Method: Prospective data was gathered on two cohorts of consecutive patients undergoing surgery for single level symptomatic lumbar spinal stenosis. The cohorts were matched for age, level of surgery and follow up. The X-Stop interspinous distraction device was compared to a standard non instrumented decompression.

There were 36 patients, 18 patients in each group, average age 66, average follow up 8 months. There was no commercial support or funding of any sort. Outcome measures were the Oswestry Disability Index (ODI), visual analogue for pain (VAS), and self perceived walking distance in yards. N.I.C.E. guidance IPG 165 was given to all interspinous distraction device patients.

Results: Pre op patient assessed walking distance in the lumbar decompression group was 152 yards; there was a 6-fold improvement to 925 yards. The interspinous distraction device had a 7 fold improvement on average, from 181 yards to 1313 yards. The improvement in ODI was most marked in the decompression group, pre surgery 61%, post surgery 29%. The interspinous group improved from 45% to 32%.

This was a clinically significant and statistically significant difference P=0.002 in favour of simple decompression. The VAS was 7.88 improving to 3.05 in the decompression group, whereas the interspinous distraction group the change was from 7.3 to 4. Complications were 3 spinous process fractures and one late migration of implant in the distraction group. There were 2 incidental durotomies and one epidural bleed greater than a litre in the decompression group. Six of the interspinous distraction devices already demonstrate lucent zones around the implant at post op follow up the significance of which is not clear.

Conclusion: There is a clinical and statistical significant difference in favour of the established procedure of lumbar decompression in terms of improvement in Oswestry Disability Index in this study. Caution with, and scrutiny of new implants and procedures is an essential component of clinical judgement and governance.