265 - Comparison of Clinical Outcomes Following Treatment of Degenerative Di...

#265 Comparison of Clinical Outcomes Following Treatment of Degenerative Disc Disease or Degenerative Spondylolisthesis with Minimally Invasive Lateral Interbody Fusion

General Session: Advocacy of MIS

Presented by: K. Khajavi


K. Khajavi (1), (2)
A.Y. Shen (1), (2)
A. Hutchison (1), (2)

(1) Georgia Spine and Neurosurgery Center, Atlanta, GA, USA
(2) The INSPIRE Foundation, Atlanta, GA, USA


Introduction: Degenerative spondylolisthesis (DS) is a well-accepted indication for lumbar interbody fusion (IBF), while degenerative disc disease (DDD) remains a controversial indication. The purpose of this study was to compare mid-term (12 month) improvement in clinical outcomes between DDD and DS patients treated with a minimally invasive (MI) 90° lateral, retroperitoneal, transpsoas approach for anterior IBF.

Methods: 20 DDD and 60 DS patients were identified from a series of 184 consecutive patients who underwent an MI lateral IBF at a single institution between 2006 and 2011 and were followed through an IRB-approved, prospective registry (ProSTOS, PhDx). Variables collected included demographic, treatment, complication, clinical outcome (visual analog scale (VAS) back (LBP) and leg pain (LP), disability (ODI), and quality of life (SF-36 PCS and MCS), and patient satisfaction. Statistical analysis included frequency and ANOVA testing, and longitudinal data were analyzed using general mixed linear models with compound-symmetric covariance matrices. Significance was accepted at the 0.05 level.

Results: Compared to DS patients, DDD patients were younger with lower baseline LBP (DDD: 6.7; DS: 8.0; p< 0.001). Fewer DDD patients underwent an additional posterior procedure, and subsequently, had significantly shorter OR time, EBL, and LOS (Table 1).

Average follow-up was 13.4 and 14.8 months for DDD and DS groups, respectively (p=0.5017). Complications occurred in one (5%) DDD patient (1 UTI) and three (5%) DS patients (1 myocardial infarction, 1 urinary retention, 1 mild dorsiflexion weakness). There were no cases of symptomatic pseudoarthroses or hardware failure.

Not adjusting for baseline or treatment differences, percent improvement from baseline to 12 months post-operative were similar between groups for ODI, LP, and PCS, but LBP improvement was less for DDD patients (p< 0.001). Furthermore, a high proportion of patients in both groups reached each substantial clinical benefit (SCB) threshold (defined as the following percentage improvements from baseline: ODI≥36.8%; LBP≥41.4%; LP≥38.8%; PCS≥19.4%) and these proportions were not statistically different between groups (Table 2).

Patient satisfaction was also similar between groups, with 90% DDD and 95% DS patients reported being satisfied with their outcomes, and 90% of patients in both groups would choose the same procedure again.

Conclusion: MI lateral IBF resulted in significant clinical improvement, low complications rates, and high patient satisfaction for both DDD and DS patients. Clinical efficacy was nearly identical between the two groups. In properly selected patients, MI lateral IBF appears to be a safe and effective treatment for both DDD and DS.

Patient demographic and treatment variables.

Clinical results at 12 months post-operative.