1527. Correlation between ODI and PROMIS in Minimally Invasive Lumbar Decompression Surgery

Authors: Avani Vaishnav; Steven McAnany, MD; Brittany Haws, MD; Benjamin Khechen, BA; Kern Singh, MD; Catherine Gang, MPH; Sheeraz Qureshi, MD, MBA (New York, NY)

Introduction:
As the focus in spine surgery shifts from radiographic to patient-centric outcomes, patient-reported outcomes measures(PROMs) are increasingly being used. Therefore, it is vital to evaluate these tools.

Purpose:
To assess the correlation between Oswestry Disability Index(ODI) and Patient-Reported Outcome Measurement Information System Physical Function(PROMIS-PF) in patients undergoing minimally invasive lumbar decompression. 

Methods:
PROMs collected pre-operatively and 6 weeks, 3 months, 6 months and 1 year post-operatively on 243 patients who underwent minimally invasive lumbar decompression surgery were analyzed; sub-group analysis by number of levels was performed.

Paired Samples t-test was used to analyze change in ODI and PROMIS. Minimal Clinically Important Difference(MCID) of 12.8 for ODI was used to assess the number of patients experiencing a clinically significant improvement. Pearson product-moment correlation was used to determine the correlation.

Results:
The improvement in ODI and PROMIS-PF from pre-operatively to each follow-up was statistically significant in 1 and 2-level cases, but not in 3-level cases. 59.1% of patients had an improvement >MCID for ODI by 6 weeks, 62% by 3 months, 58.3% by 6 months and 64.9% by 1 year.

Overall, there was a statistically significant negative correlation at all time-points, which was moderate preoperatively(r=-0.59,n=243,p<0.0001), strong at 6-weeks(r=-0.70,n=150,p<0.0001), very strong at 3-months(r=-0.80,n=95,p<0.0001), strong at 6-months(r=-0.75,n=78,p<0.0001), and very strong 1-year(r=-0.83,n=50,p<0.0001). Similarly, in 1- and 2-level surgery, there was a statistically significant negative correlation at all time-points, which was moderate preoperatively and ranged from strong to very strong the post-operatively. In contrast, in 3-level surgery the correlation was not statistically significant at any time-point.

Conclusion: 
The results of our study show a statistically significant moderate to very strong, negative correlation between ODI and PROMIS-PF, except in 3-level lumbar decompression. Thus, PROMIS-PF is a good surrogate for ODI. Larger studies are warranted to evaluate the utility and value of this outcome measure.