General Session: Thoraco-Lumbar Degenerative

Presented by: K. Kudaravalli - View Audio/Video Presentation (Members Only)

Author(s):

A. Narain(1), F. Hijji(1), K. Kudaravalli(1), K. Yom(1), N. Shoshana(1), K. Singh(1)

(1) Rush University Medical Center, Orthopaedic Surgery, Chicago, IL, United States

Abstract

Introduction: Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is an effective treatment for lumbar degenerative disorders. ASA score has previously been associated with major operative complications, increased direct costs, and increased 30-day mortality rates following orthopaedic procedures. However, few studies have analyzed ASA score in a population of patients undergoing minimally invasive spine procedures. In this context, the purpose of this study is to examine for an association between preoperative ASA score and improvements in patient-reported outcomes (PRO) including Oswestry Disability Index (ODI), Visual Analogue Scale (VAS) back pain, and VAS leg pain after MIS TLIF.

Methods: A prospectively maintained surgical database of patients who underwent a primary, single-level MIS TLIF for degenerative pathology between 2010-2016 was reviewed. Patients were excluded if they had incomplete preoperative PRO survey data. Patients were grouped based on ASA score ≤ 2 and ASA score > 2. ASA score was tested for association with demographics, procedural characteristics, preoperative ODI, and preoperative Visual Analog Scale (VAS) back and leg pain scores using student's t-test, chi-square analysis, and Fisher's exact test for continuous, categorical, and non-parametric variables, respectively. Postoperative improvement in ODI, VAS leg, and VAS back scores between ASA score cohorts was then compared using linear (continuous) or Poisson regression with robust error variance (categorical) adjusted for patient demographics, preoperative characteristics, and preoperative PRO score.

Results: After exclusion of all patients with incomplete preoperative PRO data, 113 patients were included in this analysis. 91 patients (80.53%) had an ASA score ≤ 2, and 22 (19.47%) had an ASA score > 2. There were no statistically significant differences in demographic characteristics or preoperative ODI, VAS back, and VAS leg score between ASA cohorts (p>0.05 for each). There were also no statistically significant differences in operative characteristics, preoperative diagnosis, or surgical instrumentation between ASA cohorts (p>0.05 for each). ASA cohorts demonstrated no statistically significant differences in PRO improvement at 6-week, 12-week, or 6-month postoperative time points (p>0.05 for each).

Conclusion: The results of this study suggest that ASA score is not associated with degree of improvement in PRO scores after MIS TLIF. As such, patients with higher comorbidity burden are likely to achieve similar improvements in disability and pain following MIS TLIF compared to those with lower comorbidity burden.

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