1526. Correlation between NDI, PROMIS and SF-12 in Minimally Invasive Cervical Spinal Surgery

Authors: Avani Vaishnav; Catherine Gang, MPH; Steven McAnany, MD; Sravisht Iyer, MD; Todd Albert, MD; 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 becoming important. Thus, it is vital to evaluate new outcome measures.

Purpose: To evaluate the correlation between Neck Disability Index(NDI), Patient Reported Outcome Measurement Information System Physical Function(PROMIS-PF) and Short Form-12 Physical Health Score(SF-12 PHS) in patients undergoing minimally invasive cervical spinal surgery.

PROMs collected pre-operatively and 2 weeks, 6 weeks, 3 months and 6 months post-operatively of patients undergoing cervical spine surgery were analyzed using Pearson product-moment correlation.

Of the 86 patients included, 50 underwent ACDF, 24 Cervical Disc Replacement and 12 Posterior Cervical Decompression. NDI decreased from 36.32+19.62 pre-operatively to 21.81+16.32 at 6-months. Similarly, PROMIS-PF and SF-12 PHS improved from 19.19+8.05 to 46.13+7.12 and 36.70+9.63 to 41.41+11.61, respectively at 6-months.

A statistically significant negative correlation was seen between NDI and PROMIS-PF at all time-points, which was moderate pre-operatively(r=-0.530,n=67,p<0.0001),at 2-weeks(r=-0.598,n=60,p<0.0001), 6-weeks(r=-0.559,n=54,p<0.0001), and 6-months(r=-0.498,n=27,p=0.008);and strong at 3-months(r=-0.663,n=18,p=0.003).

A statistically significant, negative correlation was also seen between SF-12 PHS and NDI at all time-points, which was moderate pre-operatively(r=-0.550,n=76,p<0.0001) and at 6 weeks(r=-0.562,n=63,p<0.0001); and strong at 2 weeks(p=-0.717,n=75,p<0.0001), 3 months(r=-0.635,n=51,p<0.0001) and 6 months(r=-0.628,n=37,p<0.0001).

There was a statistically significant positive correlation between SF-12 PHS and PROMIS-PF at all time-points, which was strong pre-operatively(r=0.721,n=69,p<0.0001) and at 6 weeks(r=0.717,n=52,p<0.0001) and 3 months(r=0.698,n=36,p<0.0001); and moderate at 2 weeks(r=0.570,n=60,p<0.0001) and 6 months(r=0.476,n=27,p=0.012).

The results of our study suggest that correlation between SF-12 PHS and PROMIS-PF, and SF-12 PHS and NDI is stronger than the correlation between NDI and PROMIS-PF. These findings suggest that PROMIS is a better indicator of overall physical health rather than impairment due to cervical spine disease, as demonstrated by a strong correlation of PROMIS-PF with SF-12 PHS, but a moderate correlation with NDI. Thus, larger studies are warranted to determine the utility and applicability of this outcome measure in common cervical spinal conditions.