• Evgenii Belykh, Alexander V Krutko, Evgenii S Baykov, Morgan B Giers, Mark C Preul, and Vadim A Byvaltsev.
• Irkutsk Scientific Center of Surgery and Traumatology, Bortsov Revolyutsii str., 1, Irkutsk, 664003, Russia; Department of Neurosurgery, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd, Phoenix, AZ 85013, USA; Department of Neurosurgery, Irkutsk State Medical University, Krasnogo vosstaniya str., 1, Irkutsk, 664003, Russia.
• Spine J. 2017 Mar 1; 17 (3): 390-400.

Background ContextRecurrence of lumbar disc herniation (rLDH) is one of the unfavorable outcomes after microdiscectomy. Prediction of the patient population with increased risk of rLDH is important because patients may benefit from preventive measures or other surgical options.PurposeThe study assessed preoperative factors associated with rLDH after microdiscectomy and created a mathematical model for estimation of chances for rLDH.Study Design/SettingThis is a retrospective case-control study.Patient SampleThe study includes patients who underwent microdiscectomy for LDH.Outcome MeasuresLumbar disc herniation recurrence was determined using magnetic resonance imaging.MethodsThe study included 350 patients with LDH and a minimum of 3 years of follow-up. Patients underwent microdiscectomy for LDH at the L4-L5 and L5-S1 levels from 2008 to 2012. Patients were divided into two groups to identify predictors of recurrence: those who developed rLDH (n=50) within 3 years and those who did not develop rLDH (n=300) within the same follow-up period. Multivariate analysis was performed using patient baseline clinical and radiography data. Non-linear, multivariate, logistic regression analysis was used to build a predictive model.ResultsRecurrence of LDH occurred within 1 to 48 months after microdiscectomy. Preoperatively, patients who developed rLDH were smokers (70% vs. 27%, p<.01; odds ratio [OR]=6.31, 95% confidence interval [CI]: 3.27-12.16) and had higher body mass index (29.0±6.1 vs. 27.0±4.3, p=.03; OR=1.09 per 0.01 unit change). Radiological parameters that were associated with rLDH were higher disc height index (0.35±0.007 vs. 0.26±0.002, p<.001), higher segmental range of motion (9.8±0.28° vs. 7.6±0.11°, p<.001; OR=0.53 per 0.01 unit change), and lower central angle of lumbar lordosis (33.4±0.81° vs. 47.1±0.47°, p<.001; OR=0.53 per 0.01 unit change). Additionally, Pfirrmann grade 3 (OR=16.62, 95% CI: 8.10-34.11), protrusion type of LDH (OR=5.90, 95% CI: 3.06-11.36), and Grogan sclerosis grades 3 and 4 (OR=4.81, 95% CI: 2.50-9.22) were also associated with rLDH. Multivariate non-linear modeling allowed for more accurate prediction of rLDH (90% correct prediction of rLDH; 99% correct prediction of no rLDH) than other univariate logit models.ConclusionsPreoperative radiographic parameters in patients with LDH can be used to assess the risk of recurrence after microdiscectomy. The multifactorial non-linear model provided more accurate rLDH probability estimation than the univariate analyses. The software developed from this model may be implemented during patient counseling or decision making when choosing the type of primary surgery for LDH.Copyright © 2016 Elsevier Inc. All rights reserved.

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