Minimally Invasive Decompression In Focal Lumbar Spinal Stenosis With Or Without Stable Spondylolisthesis - Comparative Outcomes And Re-operation Rates At 2 Yrs And Beyond

Presented at SMISS Annual Forum 2014
By Y. Rampersaud MD, FRCS9(C)
With B Chaudhary , Rohit Amritanand ,

Disclosures: Y. Rampersaud MD, FRCS9(C) Consulting Fees: Medtronic B Chaudhary None, Rohit Amritanand None,

Introduction:
Surgical outcomes for degenerative lumbar spondylolisthesis (DLS) have been historically shown to be better with instrumented fusion & decompression. However with greater utilization of less invasive midline sparing approaches, recent reported series question the need for fusion in selected patients.

Aims/Objectives:
The primary objective of the study was to assess surgical & patient reported outcomes following decompression alone in selected patients with DLS compared to those with noDLS.

Methods:
A single surgeon consecutive series of patients undergoing surgery for lumbar spinal stenosis (LSS) with a minimum of 2 year follow up were assessed as part of an ongoing prospective observational study. Primary outcome measures were Oswestry Disability Index (ODI) scores & re-operation rates. Secondary outcomes were pre & postoperative visual analogue scale (VAS) scores for leg & back pain & satisfaction ratings post surgery. Decompression alone was chosen for patients with neurogenic claudication/ radiculopathy no or tolerable mechanical back pain and no dynamic instability (<5mm of motion). All patients underwent bilateral decompression via a unilateral minimally invasive approach.

Results:
157 LSS patients had surgery from Jan.2007 to Jun.2011, 62 with DLS & 95 without DLS. The cohorts were comparable for age (p=0.51) & pre-operative ODI (p=0.74). The DLS cohort had greater proportion of women (p=0.02). There was significant ODI improvement in both cohorts (DLS mean baseline ODI improved from 40 to 23 at 2 years [p < 0.01] & in noDLS from 39 to 26 [p < 0.01]). The change in ODI was comparable in the two cohorts (p=0.18). VAS leg & back scores similarly improved between cohorts (p=0.50 & 0.22, respectively). Satisfaction was also similar in the 2 groups (88% of DLS patients rated their post surgical satisfaction scores as favourable whilst for noDLS patients this was 82% [p=0.56]. In the DLS cohort, 3 patients (6.4%) had a reoperation at a mean of 2.35 years (range 1-3.5 years) with a mean follow-up of 3.06 years (2-4 years). For those without DLS, 5 patients (5.2%) had a reoperation at a mean of 3.29 years (1-6 years) at a mean follow-up of 4.49 years (2-6 years)

Conclusions:
Using the aforementioned selection criteria DLS patients undergoing decompression alone have excellent intermediate term results comparable to LSS patients without DLS. For highly selected DLS patients, successful outcomes without a fusion are achievable.