title: Do measures of surgical effectiveness at 1 year after lumbar spine surgery accurately predict 2-year outcomes?
abstract: OBJECTIVE With the recent passage of the Patient Protection and Affordable Care Act, there has been a dramatic shift toward critical analyses of quality and longitudinal assessment of subjective and objective outcomes after lumbar spine surgery. Accordingly, the emergence and routine use of real-world institutional registries have been vital to the longitudinal assessment of quality. However, prospectively obtaining longitudinal outcomes for patients at 24 months after spine surgery remains a challenge. The aim of this study was to assess if 12-month measures of treatment effectiveness accurately predict long-term outcomes (24 months). METHODS A nationwide, multiinstitutional, prospective spine outcomes registry was used for this study. Enrollment criteria included available demographic, surgical, and clinical outcomes data. All patients had prospectively collected outcomes measures and a minimum 2-year follow-up. Patient-reported outcomes instruments (Oswestry Disability Index [ODI], SF-36, and visual analog scale [VAS]-back pain/leg pain) were completed before surgery and then at 3, 6, 12, and 24 months after surgery. The Health Transition Index of the SF-36 was used to determine the 1- and 2-year minimum clinically important difference (MCID), and logistic regression modeling was performed to determine if achieving MCID at 1 year adequately predicted improvement and achievement of MCID at 24 months. RESULTS The study group included 969 patients: 300 patients underwent anterior lumbar interbody fusion (ALIF), 606 patients underwent transforaminal lumbar interbody fusion (TLIF), and 63 patients underwent lateral interbody fusion (LLIF). There was a significant correlation between the 12- and 24-month ODI (r = 0.82; p < 0.0001), SF-36 Physical Component Summary score (r = 0.89; p < 0.0001), VAS-back pain (r = 0.90; p < 0.0001), and VAS-leg pain (r = 0.85; p < 0.0001). For the ALIF cohort, patients achieving MCID thresholds for ODI at 12 months were 13-fold (p < 0.0001) more likely to achieve MCID at 24 months. Similarly, for the TLIF and LLIF cohorts, patients achieving MCID thresholds for ODI at 12 months were 13-fold and 14-fold (p < 0.0001) more likely to achieve MCID at 24 months. Outcome measures obtained at 12 months postoperatively are highly predictive of 24-month outcomes, independent of the surgical procedure. CONCLUSIONS In a multiinstitutional prospective study, patient-centered measures of surgical effectiveness obtained at 12 months adequately predict long-term (24-month) outcomes after lumbar spine surgery. Patients achieving MCID at 1 year were more likely to report meaningful and durable improvement at 24 months, suggesting that the 12-month time point is sufficient to identify effective versus ineffective patient care.
authors.affiliation: Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina; and.
authors.forename: Owoicho
authors.initials: O
authors.lastname: Adogwa
authors.affiliation: Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina; and.
authors.forename: Aladine A
authors.initials: AA
authors.lastname: Elsamadicy
authors.affiliation: Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina; and.
authors.forename: Jing L
authors.initials: JL
authors.lastname: Han
authors.affiliation: Department of Neurosurgery, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Joseph
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina; and.
authors.forename: Isaac
authors.initials: I
authors.lastname: Karikari
authors.affiliation: Division of Neurosurgery, Duke University Medical Center, Durham, North Carolina; and.
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Bagley
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001416:Back Pain / Q000209:etiology / Q000601:surgery; D004185:Disability Evaluation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000601:surgery; D008137:Longitudinal Studies; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011379:Prognosis; D011446:Prospective Studies; D011843:Radiculopathy / Q000150:complications / Q000601:surgery; D012042:Registries; D013123:Spinal Fusion / Q000379:methods*; D013168:Spondylolisthesis / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
keywords: ALIF = anterior lumbar interbody fusion; HRQOL = health-related quality of life; LLIF = lateral interbody fusion; MCID = minimum clinically important difference; MCS = Mental Component Summary; MDC = minimum detectable change; ODI = Oswestry Disability Index; PCS = Physical Component Summary; TLIF =transforaminal lumbar interbody fusion; VAS = visual analog scale; effective measures; long-term outcomes; lumbar spine; spinal surgery; surgical effectiveness; surgical outcomes