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Background Context: The proportion of patients who undergo lumbar microdiscectomy due to lumbar radiculopathy who are also overweight or obese is high. However, whether high body mass index (BMI) affects clinical outcomes is not well-studied., Purpose: To investigate the difference in the clinical course between normal weight, overweight, and obese patients with radiculopathy who underwent lumbar microdiscectomy followed by physical therapy and to evaluate whether high BMI is associated with poor recovery., Study Design/setting: A prospective cohort study with a 12-month follow-up was conducted in a multidisciplinary clinic., Patient Sample: We included 583 patients (median [IQR] age: 45 [35-52] years; 41% female) with clinical signs and symptoms of lumbar radiculopathy, consistent with magnetic resonance imaging findings, who underwent microdiscectomy followed by postoperative physical therapy., Outcome Measures: Outcomes were leg pain and back pain intensity measured with a visual analogue scale, disability measured with the Roland Morris Disability Questionnaire at 3 and 12-month follow-ups, and complications., Methods: Patients were classified as being normal weight (46.9%), overweight (38.4%), or obese (14.7%). A linear mixed-effects model was used to assess the difference in the clinical course of pain and disability between the three BMI categories. The association between BMI and outcomes was evaluated using univariable and multivariable logistic regression analyses., Results: All three patient groups experienced a significant improvement in leg pain, back pain, and disability over 3 and 12-month follow-up. Patients who were overweight, obese, or normal weight experienced comparable leg pain (p=.14) and disability (p=.06) over the clinical course (p=.14); however, obese patients experienced higher back pain (MD=-6.81 [95%CI: -13.50 to -0.14]; p=.03). The difference in back pain scores was not clinically relevant., Conclusions: In the first year following lumbar microdiscectomy, patients demonstrated clinical improvements and complications that were unrelated to their preoperative BMI., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objectives: The clinical course of lumbar radiculopathy following microdiscectomy and post-operative physiotherapy varies substantially. No prior studies assessed this variability by deriving outcome trajectories. The primary aims of this study were to evaluate the variability in long-term recovery after lumbar microdiscectomy followed by post-operative physiotherapy and to identify outcome trajectories. The secondary aim was to assess whether demographic, clinical characteristics and patient-reported outcome measures routinely collected at baseline could predict poor outcome trajectories., Methods: We conducted a prospective cohort study with a 24-month follow-up. We included 479 patients with clinical signs and symptoms of lumbar radiculopathy confirmed by Magnetic Resonance Imaging findings, who underwent microdiscectomy and post-operative physiotherapy. Outcomes were leg pain and back pain measured with Visual Analogue Scales, and disability measured with the Roland-Morris Disability Questionnaire. Descriptive statistics were performed to present the average and the individual clinical course. A latent class trajectory analysis was conducted to identify leg pain, back pain, and disability outcome trajectories. The best number of clusters was determined using the Bayesian Information Criterion, Akaike's information criteria, entropy, and overall interpretability. Prediction models for poor outcome trajectories were assessed using multivariable logistic regression analyses., Results: Several outcome trajectories were identified. Most patients were assigned to the 'large improvement' trajectory (leg pain: 79.3%; back pain: 70.2%; disability: 59.5% of patients). Smaller proportions of patients were assigned to the 'moderate improvement' trajectory (leg pain: 7.9%; back pain: 10.6%; disability: 20.7% of patients), the 'minimal improvement' trajectory (leg pain: 4.9%, back pain: 6.7%, disability: 16.3% of patients) and the 'relapse' trajectory (leg pain: 7.9%; back pain: 12.5%; disability: 3.5%). Approximately one-third of patients (32.6%) belonged to one or more than one poor outcome trajectory. Patients with previous treatment (prior back surgery, injection therapy, and medication use) and those who had higher baseline pain and disability scores were more likely to belong to the poor outcome trajectories in comparison to the large improvement trajectories in back pain, leg pain and disability, and the moderate improvement trajectory in disability. The explained variance (Nagelkerke R2) of the prediction models ranged from 0.06 to 0.13 and the discriminative ability (Area Under the Curve) from 0.66 to 0.73., Conclusion: The clinical course of lumbar radiculopathy varied following microdiscectomy and post-operative physiotherapy, and several outcome trajectories could be identified. Although most patients were allocated to favorable trajectories, one in three patients was assigned to one or more poor outcome trajectories following microdiscectomy and post-operative physiotherapy for lumbar radiculopathy. Routinely gathered data were unable to predict the poor outcome trajectories accurately. Prior to surgery, clinicians should discuss the high variability and the distinctive subgroups that are present in the clinical course with their patients., (Copyright © 2022 The Authors. Published by Elsevier B.V. All rights reserved.)

Study Design: Prospective cohort study., Objective: To develop and internally validate prognostic models based on commonly collected preoperative data for good and poor outcomes of lumbar microdiscectomy followed by physiotherapy., Summary of Background Data: Lumbar microdiscectomy followed by physiotherapy is a common intervention for lumbar radiculopathy. Postoperatively, a considerable percentage of people continues to experience pain and disability. Prognostic models for recovery are scarce., Methods: We included 298 patients with lumbar radiculopathy who underwent microdiscectomy followed by physiotherapy. Primary outcomes were recovery and secondary outcomes were pain and disability at 12 months follow-up. Potential prognostic factors were selected from sociodemographic and biomedical data commonly captured preoperatively. The association between baseline characteristics and outcomes was evaluated using multivariable logistic regression analyses., Results: At 12 months follow-up, 75.8% of the participants met the criterion for recovery. Variables in the model for good recovery included: younger age, leg pain greater than back pain, high level of disability, and a disc herniation at another level than L3-L4. The model for poor recovery included: lower educational level, prior back surgery, and disc herniation at L3-L4. Following internal validation, the explained variance (Nagelkerke R) and area under the curve for both models were poor (≤0.02 and ≤0.60, respectively). The discriminative ability of the models for disability and pain were also poor., Conclusion: The outcome of microdiscectomy followed by postoperative physiotherapy cannot be predicted accurately by commonly captured preoperative sociodemographic and biomedical factors. The potential value of other biomedical, personal, and external factors should be further investigated., Level of Evidence: 3.