Object. The natural history of Modic changes (MCs) in the lumbar spine is often marked by conversion from one type to another, but their course following lumbar discectomy remains unknown. The authors sought to study the impact of surgery on the natural history of these lesions.Methods. Forty-one patients treated with lumbar microdiscectomy between 2004 and 2005 were enrolled in this study and underwent clinical evaluation and repeat MR imaging after a median follow-up of 41 months (range 32-59 months). Preoperative and follow-up MR images were reviewed and the type, location, and extent of MCs at the operated level were recorded and compared.Results. The study population consisted of 27 men and 14 women with a mean age of 54 years (range 24-78 years). During the follow-up period, the prevalence of MCs increased from 46.3% to 78%, and 26 patients (63.4%) had Type 2 lesions at the operated level. Of the 22 patients without MCs, 4 (18.2%) converted to Type 1 and 9 (40.9%) to Type 2. Of the 5 Type 1 lesions, 3 (60%) converted to Type 2, and 2 (40%) remained Type 1 but increased in size. In contrast, none of the 14 Type 2 changes converted to another type, although 10 (71.4%) increased in extent. There were no reverse conversions to Type 0.

While short-term results of lumbar microdiscectomy (LMD) are favorable in over 85% of cases, long-term outcome is often less rewarding and tends to be similar to that of nonoperative management of lumbar disc herniation (LDH), with only 55-70% favorable results [1][2][3][4][5][6] . Low back pain (LBP) is the usual cause for the drop in patient satisfaction and has been linked to the development of post-operative segmental instability (SI) 1,[6][7][8][9][10][11][12][13] .However, whether instability is a direct consequence of surgery or whether it is part of the natural history of lumbar degenerative disc disease (DDD) is still a matter of debate 6,14,15 . Some authors have suggested that post-operative disc space collapse (DSC) of more than 25-30% after aggressive ABSTRACT: Background: The long-term outcome after lumbar microdiscectomy (LMD) may be affected by low back pain (LBP) and segmental instability, the determinants of which remain unclear. We sought to analyze the interaction between clinical, functional, and radiological variables and their impact on patient outcome. Methods: All patients who underwent LMD in 2004-2005 were invited to participate in this retrospective cohort study. Patients were re-evaluated clinically and radiologically after a three to five year follow-up. Results: Forty-one of 97 eligible patients were enrolled. Twelve patients (29.3%) reported moderate-to-severe sciatica, 12 (29.3%) had moderate LBP, and 13 (31.7%) exhibited clinical evidence of segmental instability. Thirty-eight patients (92.7%) had minimal disability and 3 (7.3%) had moderate disability. Twenty-three patients (56.1%) were fully satisfied, while 18 (43.9%) had only partial satisfaction, having expected a better outcome. Thirty-three patients (80.5%) returned to full-time work. Median disc space collapse (DSC) was 20% (range 5-66%) and L4-L5 was particularly affected. Prevalence of Modic changes increased from 46.3% to 78% with type 2 predominance. Multivariate logistic regression analysis identified the following negative prognostic factors: female sex, young age, lack of regular exercise, and chronic preoperative LBP. There was no correlation between the course of Modic changes, DSC, and patient outcome. Conclusion: Although many patients may be symptomatic following LMD, significant disability and dissatisfaction are uncommon. Female sex, young age, lack of exercise, and chronic preoperative LBP may predict a worse outcome. Disc collapse is a universal finding, particularly at L4-L5. Neither DSC nor Modic changes seem to affect patient outcome.RÉSUMÉ: Analyse clinico-radiologique des résultats de la microdiscectomie lombaire. Contexte : Le résultat à long terme de la microdiscectomie lombaire (MDL) peut être influencé par la douleur lombaire (DL) et l'instabilité segmentaire dont les facteurs déterminants sont mal connus. Le but de notre étude était d'analyser l'interaction entre des variables cliniques, fonctionnelles et radiologiques ainsi que leur impact sur le résultat chez le patient. Méthode : Tous les pat...

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