156. Two-year validation and minimum clinically important difference of VR-12 PCS

Abstract

<h3>BACKGROUND CONTEXT</h3> The 12-Item Veterans RAND physical composite score (VR-12 PCS) has been assessed for use at short-term and intermediate timepoints for lumbar fusion populations. However, it has not been validated at long-term timepoints and relevant minimum clinically important difference (MCID) values have not yet been established. <h3>PURPOSE</h3> This study assesses the long-term validity and establishes potential MCID values of VR-12 PCS in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS TLIF). <h3>STUDY DESIGN/SETTING</h3> Retrospective cohort. <h3>PATIENT SAMPLE</h3> A total of 74 patients undergoing primary, elective, single-level MIS TLIF procedures with posterior instrumentation were included. <h3>OUTCOME MEASURES</h3> Demographic characteristics, perioperative characteristics, VR-12 PCS, 12-Item Short Form (SF-12) PCS, and Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS PF). <h3>Methods</h3> A surgical database was retrospectively reviewed for primary, elective, single-level MIS TLIF procedures with posterior instrumentation. Patients were excluded if preoperative and 2-year postoperative VR-12 PCS survey data was unavailable or if procedures were indicated due to trauma, infection, or malignancy. VR-12 PCS, 12-Item Short Form (SF-12) PCS, and Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS PF) measures were recorded at preoperative, 6-week, 12-week, 6-month, 1-year, and 2-year postoperative timepoints. Responsiveness of the VR-12 measure was assessed in 2 ways: mean postoperative scores were compared to preoperative baseline values and MCID values were calculated using distribution- and anchor-based methods and used to assess improvement in VR-12 at 2-years. Convergent validity was assessed by the correlation of VR-12 PCS scores with SF-12 PCS and PROMIS PF scores at each timepoint. Floor and ceiling effects were assessed based on the total range of VR-12 PCS scores at each timepoint. <h3>Results</h3> A total of 74 patients were included. VR-12 PCS demonstrated significant postoperative improvements at all timepoints from 12-weeks to 2-years. Distribution-based MCID was calculated as 3.0 (⅓ SD) with an achievement rates of 73.0%. Anchor-based MCIDs were calculated as 7.8, 8.7 (cross-sectional) (p=.049 and p=<.001), and 8.1 (longitudinal) (p=.040) with achievement rates of 52.7%, 50.0%, and 52.7%, respectively. Strong correlations of VR-12 PCS with SF-12 PCS and PROMIS PF were demonstrated at all timepoints. No significant floor or ceiling effects were detected. <h3>Conclusions</h3> VR-12 PCS demonstrated good responsiveness, excellent convergent validity, and no significant floor or ceiling effects up to 2-years following MIS TLIF. Therefore, we recommend VR-12 PCS as a valid measure of long-term physical function in patients undergoing MIS TLIF. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.