Downloaded from http://journals.lww.com/jspinaldisorders by BhDMf5ePHKbH4TTImqenVBLNPkpHwi7kPIHkCDX/3aaqcvCmVRvFpxLoWFFmriUSGDaTF2N7UKo= on 07/25/2020 The Impact of Comorbidity Burden on Postoperative PROMIS Physical Function Following Minimally Invasive Transforaminal Lumbar Interbody Fusion James M. Parrish, MPH, Nathaniel W. Jenkins, MS, Nadia M. Hrynewycz, BS, Thomas S. Brundage, BS, Joon S. Yoo, BA, and Kern Singh, MD Study Design: This was a retrospective cohort study. Objective: To assess the utility of Patient-Reported Outcome Measurement Information System Physical Function (PROMIS PF) in assessing postoperative recovery on the basis of the co- morbidity burden after minimally invasive transforaminal lum- bar interbody fusion (MIS TLIF). Summary of Background Data: Few studies have evaluated the effect of comorbidity burden in long-term clinical recovery after MIS TLIF. Methods: Patients undergoing primary, 1-level to 2-level MIS TLIF were retrospectively reviewed and stratified on the basis of Charlson Comorbidity Index (CCI) score: 0 points (no comorbidities), 1–2 points (low CCI), ≥ 3 points (high CCI). CCI was tested for an association with demographic characteristics and perioperative vari- ables using χ 2 analysis and multivariate linear regression. Multivariate linear regression was utilized to determine the association between CCI cohorts and PROMIS PF. Results: A total of 187 1-level and 2-level MIS TLIF patients were included: 53 had no comorbidities, 78 had a low CCI, and 56 a high CCI. One patient in the high CCI group experienced nonunion. Patients reported similar PROMIS PF scores preoperatively and up to 1-year postoperatively. Each cohort experienced a similar im- provement in PROMIS PF scores from baseline at each postoperative time point. For patients without comorbidities, the change in the postoperative PROMIS PF score from baseline was signi ficant at every postoperative time point. However, for the patients with ≥ 1 comorbidities, the change in the postoperative PROMIS PF score from baseline was significant at the 3-month, 6-month, and 1-year time points, however, the change from baseline to 6 weeks was not significant. Conclusions: In this investigation, the authors compared the clinical recovery of patients with varying comorbidities undergoing an MIS TLIF using PROMIS PF. Regardless of comorbidity, patients reported similar preoperative PROMIS PF scores and had similar improvements throughout the 1-year follow-up. This study estab- lished that PROMIS PF is an effective tool to evaluate the recovery of patients with differing comorbidities after MIS TLIF. Key Words: minimally invasive transforaminal lumbar interbody fusion, MIS TLIF, PROMIS, patient-reported outcome meas- urement information system, physical function, Charlson Co- morbidity Index, clinical recovery, lumbar spine (Clin Spine Surg 2020;33:E294–E298) P atient-Reported Outcome Measurement Information System (PROMIS) has been widely implemented to evaluate patient health before and after a variety of or- thopedic and spinal procedures. The instrument’s computer adaptive testing algorithm has allowed for a more efficient method of clinical data collection compared with legacy outcome measures. 1–3 Since the introduction of PROMIS, multiple domains have been created to target physical, mental, or social health. Specifically, the PROMIS Physical Function (PF) domain has been particularly valuable in spine surgery because of its ability to accurately assess strength, mobility, and coordination. Although PROMIS PF has been widely introduced in the clinical setting, there are still unanswered questions regarding its utility in as- sessing outcomes of at-risk populations after common spine procedures such as lumbar fusion. Within the field of orthopedic surgery, the effect of comorbidity burden on postoperative outcomes and com- plication rates has been thoroughly investigated with respect to a variety of elective procedures. 4–8 In relation to lumbar spine procedures, the presence of comorbidities has also been associated with an increased risk for complications, length of inpatient stay, and overall poor outcomes after surgery. 9,10 Thus, enhanced knowledge of associations between co- morbidity burden and postoperative outcomes may not only improve patient care but may also reduce health care costs. Although previous studies have investigated the effect of comorbidity burden on perioperative outcomes, few have evaluated these variables in long-term clinical recovery after common spinal procedures such as minimally invasive Received for publication May 23, 2019; accepted December 13, 2019. From the Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL. IRB Approval: ORA #14051301. The authors declare no conflict of interest. Reprints: Kern Singh, MD, Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St, Suite #300, Chicago, IL 60612 (e-mail: kern.singh@rushortho.com). Supplemental Digital Content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal’s website, www. jspinaldisorders.com. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved. PRIMARY RESEARCH E294 | www.clinicalspinesurgery.com Clin Spine Surg  Volume 33, Number 6, July 2020 Copyright r 2020 Wolters Kluwer Health, Inc. All rights reserved.