78 - Clinical Outcome Following a Minimally Invasive Lumbar Decompression T...

#78 Clinical Outcome Following a Minimally Invasive Lumbar Decompression Technique for the Treatment of Lumbar Spinal Stenosis

General Session: Advocacy of MIS

Presented by: M. Hisey


M.S. Hisey (1)
C. Bonsignore (2)
W.D. Bradley (1)
S. Verma-Kurvari (2)
D.D. Ohnmeiss (2)

(1) Texas Back Institute, Denton, TX, USA
(2) Texas Back Institute Research Foundation, Plano, TX, USA


Introduction: Lumbar spinal stenosis is a significant problem, particularly in older patients. After failure of non-operative management, lumbar decompression, sometimes combined with fusion, has been the standard treatment for these patients. Several minimally invasive surgery (MIS) techniques have now been described for the treatment of stenosis. One such treatment involves the use of a shaver that is manually reciprocated across the joint to remove the compressive tissue. The purpose of this study was to evaluate the early clinical outcome associated with the use of this MIS decompression procedure.

Methods: This study is based on a review of 34 consecutive patients, beginning with the first case experience, who underwent lumbar decompression using the iO-Flex system (Baxano). Two additional patients underwent decompression using this technique, but it was combined with a posterior fusion procedure and those cases were not included in this analysis. The decompression technique involves using small, flexible instruments that traverse the neruoforamen to shave away compressive tissue from the lateral recess. The approach is ventral to dorsal within the space rather than the more common medial to lateral approach. The shaver instrument is gently pulled back and forth passed multiple times to remove the desired amount of tissue.

The mean patient age at the time of surgery was 63.4 years, ranging from 43 to 81 years. Further descriptive of the patients is provided in Table 1. The mean duration of time of surgery to preparation of this abstract was 11.2 months, ranging from 3 to 34 months.

Results: The mean operative time was 93.8 min and the mean estimated blood loss was 115.0 ml. In two patients, a dural tear occurred, one of which required re-operation for repair. One patient underwent traditional decompression approximately 3 months after the MIS procedure. There were no other re-operations or procedure-related complications in this series. Based on changes when comparing the pre- to post-operative VAS scores, leg and back pain improved significantly (p< 0.05; paired t-test). The mean leg pain score improved 39.7% and back pain 53.7%. ODI scores improved 13.6%, which was not significant.

Discussion: To date, there is little information available on the MIS decompression technique used in this study. Our results found significant improvement in pain scores and a low rate of re-operation for additional decompression. MIS decompression is particularly appealing in older patients for whom more extensive surgery may not be feasible due to risk of complications and/or possibly compromised ability to recover. These early results are encouraging, and further evaluation of this technique, including longer follow-up is underway.

Table 1. Description of patients.