RETROSPECTIVE COHORT STUDY COMPARING OPEN DECOMPRESSION AND INTERSPINOUS DEVICE INSERTION FOR LUMBAR SPINAL STENOSIS

Abstract

Aims: To assess whether patients undergoing one or two level open decompression of their lumbar spinal stenosis could have an interspinous device inserted with equal or less risk of complications and whether patient satisfaction is improved.

Background: The reported incidence of lumbar spinal stenosis [LSS] varies [1.7% to 8%], as do the results of open surgical decompression. Implanting interspinous devices [ID] to relieve symptoms of LSS is a newer concept which has good short term results.

Patients: Data was collected from 48 consecutive patients undergoing one or two level decompressions for symptoms of lumbar spinal stenosis from February 2008 to March 2009.

Methods: Retrospective case note analysis of clinic letters, operation notes and inpatient stays was carried out. Two types of interspinous device (BacJac and X-stop) were used and the results have been collated.

Results: 29 open decompressions [22 one level, 7 two level] were performed compared to 19 interspinous device insertions [7 one level, 9 two level]. Surgery was performed for patients with leg pain although 27 patients had concomitant back pain.

The average age of the patients for open decompression (63yrs +/− 11) compared to interspinous device (63yrs +/− 9) was equal. Male to female ratio for Open Vs ID [1.4:1 Vs 1.1:1] did not differ significantly (p = 0.39). The ASA grades were higher for the interspinous device group with an average of 2.5 compared to 2.1 in the open group.

The length of anaesthetic was on average shorter for the interspinous devices, which included a higher proportion of 2 level decompressions. The average length of stay on average was identical at 1.3 days, complications were similar [5% Vs 7%] with patient satisfaction higher [81% Vs 68%], although statistically insignificant [p=0.79]

Conclusion: There are certain criteria advised by the American Academy of Orthopaedic Surgeons to aid in selection of suitable patients for interspinous device insertion. 10 of the 29 patients for open decompression fitted these criteria.

Interspinous device insertion is a less invasive procedure and can be carried out on patients with a higher anaesthetic risk, even being performed under sedation. It should be considered for patients with symptoms of LSS instead of open decompression as there is no effect on length of stay or complication rate and there is a trend toward a decrease in anaesthetic time with improved patient satisfaction in the short term.