A prognostic model for failure and worsening after lumbar microdiscectomy: a multicenter study from the Norwegian Registry for Spine Surgery

• Published in: Acta Neurochirurgica
• Main Authors: Werner, David Andreas Thomas, Grotle, Margreth, Småstuen, Milada Cvancarova, Gulati, Sasha, Nygaard, Øystein Petter, Salvesen, Øyvind, Ingebrigtsen, Tor, Solberg, Tore
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer 2021
• Subjects: Microdiscectomy; Outcomes; Patient-reported outcome measures; PROMs; Qualities; Oswestry Disability Index; ODI; Lumbar disc surgery; Norway; Northern Norway
• Online Access: https://hdl.handle.net/11250/2828843; https://doi.org/10.1007/s00701-021-04859-3

Objective: To develop a prognostic model for failure and worsening 1 year after surgery for lumbar disc herniation. Methods: This multicenter cohort study included 11,081 patients operated with lumbar microdiscectomy, registered at the Norwegian Registry for Spine Surgery. Follow-up was 1 year. Uni- and multivariate logistic regression analyses were used to assess potential prognostic factors for previously defined cut-offs for failure and worsening on the Oswestry Disability Index scores 12 months after surgery. Since the cut-offs for failure and worsening are different for patients with low, moderate, and high baseline ODI scores, the multivariate analyses were run separately for these subgroups. Data were split into a training (70%) and a validation set (30%). The model was developed in the training set and tested in the validation set. A prediction (%) of an outcome was calculated for each patient in a risk matrix. Results: The prognostic model produced six risk matrices based on three baseline ODI ranges (low, medium, and high) and two outcomes (failure and worsening), each containing 7 to 11 prognostic factors. Model discrimination and calibration were acceptable. The estimated preoperative probabilities ranged from 3 to 94% for failure and from 1 to 72% for worsening in our validation cohort. Conclusion: We developed a prognostic model for failure and worsening 12 months after surgery for lumbar disc herniation. The model showed acceptable calibration and discrimination, and could be useful in assisting physicians and patients in clinical decision-making process prior to surgery. The main author, David Werner, has received grants from the Regional Health Authority of Northern Norway, and the Norwegian Medical Association – Foundation for quality improvement and patient safety, for the purpose of this project. publishedVersion