Decompression surgery for lumbar spinal stenosis is a common procedure. After surgery, segmental instability sometimes occurs, therefore, different methods for restabilization have been developed. Dynamic stabilization systems have been designed to improve segmental stability. In this study, clinical results of patients with lumbar spinal stenosis that underwent decompression and stabilization with the Accuflex dynamic system are presented; clinical, radiographic, and magnetic resonance imaging (MRI) findings are fully described. Improvements in all clinical measurements, including visual analog scale for back and leg pain, Oswestry disability index, and SF-36 health status survey were noticed. At a 2-year follow-up, 22.22% of patients required hardware removal due to fatigue while in 83% of them no progression of disk degeneration was observed after implantation of the Accuflex system. Additionally, as demonstrated by the MRI images at follow up, three patients (16%) showed disk rehydration with one grade higher on the Pfirmann classification. Although a relatively high hardware failure was observed (22.22%), the use of the dynamic stabilization system Accuflex posterior to decompression procedures, showed clinical benefits and stopped the degenerative process in 83% the patients.

Lumbar stabilization exercises could be an effective treatment option in controlling pain and improving function in patients with degenerative spondylolisthesis. Further investigation with randomized controlled trials is necessary to obtain confirmation of these results.

The objective of this study is to correlate T2 relaxation time (T2RT), measured by magnetic resonance imaging (MRI) with quadriceps and hamstring strength in young participants with risk factors for knee osteoarthritis (OA). A descriptive cross-sectional study was conducted with participants between 20 and 40 years of age, without diagnosis of knee OA. Their T2 relaxation time was measured through MRI, and their muscle strength (MS) was measured with an isokinetic dynamometer. Seventy-one participants were recruited, with an average age of 28.3 ± 5.5 years; 39 (55 %) were females. Negative correlations were found between T2RT and quadriceps peak torque (QPT) in males in the femur r = -0.46 (p = 0.01), tibia r = -0.49 (p = 0.02), and patella r = -0.44 (p = 0.01). In women, correlations were found among the femur r = -0.43 (p = 0.01), tibia r = -0.61 (p = 0.01), and patella r = -0.32 (p = 0.05) and among hamstring peak torque (HPT), in the femur r = -0.46 (p = 0.01), hamstring total work (HTW) r = -0.42 (p = 0.03), and tibia r = -0.33 (p = 0.04). Linear regression models showed good capacity to predict T2RT through QPT in both genders. The present study shows that early changes in femoral, tibial, and patellar cartilage are significantly correlated with MS, mainly QPT, and that these early changes might be explained by MS, which could play an important role in pre-clinical phases of the disease.

Abstract. PURPOSE: To analyze the relationship of strength, muscular balance, and atrophy with pain and function in patients with degenerative spondylolisthesis. STUDY DESIGN: Transversal, descriptive, and observational. PATIENTS AND METHODS: Institutional review board approval was obtained for this study. Twenty six patients ages 50 years and older, with degenerative spondylolisthesis at L4-L5. Measurements included Pain Visual Analogue Scale scores (VAS), Oswestry Disability Index scores (ODI), and isokinetic trunk testing; assessment of multifidus atrophy and spinal stenosis was performed by Magnetic Resonance Imaging (MRI). STATISTICS: Statistical analysis was performed using SPSS version 17.0 software for Windows. Pearson's correlation was used to ascertain the correlation between variables. ANOVA with analysis of covariance was used to determine the correlation between the remainder variables. Significance was set at p < 0.05. RESULTS: Of the 26 patients studied, with an average age of 60.23 ± 7.6 years, 20 had grade I spondylolisthesis and 6 were grade II. Correlation between the ODI scores and spondylolisthesis grading was significant (r = 0.576, p = 0.005); correlation between agonist/antagonist ratio in the isokinetic test (predominant extensor muscles over flexors) with the ODI scores was also significant (r = 0.446, p = 0.02), regardless of spinal stenosis. No correlation was found between functionality and pain with strength or multifidus atrophy. CONCLUSION: Muscle trunk imbalance with predominance of extensor over flexor muscles is associated with functional disability. Rehabilitation programs should be designed to improve muscle balance rather than muscle strength alone.

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