Minimum 2-Year Experience with Magnetically Controlled Growing Rods for the Treatment of Early-Onset Scoliosis: A Systematic Review

Magnetically controlled growing rods have been used to treat early-onset scoliosis for the last 9 years; however, few studies have been published, with only short-term follow-up. The aim of the present study is to systematically review the outcomes of magnetically controlled growing rods in the treatment of early-onset scoliosis with a minimum of 2-year follow-up. Studies were included if patients with early-onset scoliosis (scoliosis diagnosed before 10 years of age) underwent implantation of magnetically controlled growing rods with a minimum of 2-year follow-up. The literature review and data extraction followed the established preferred reporting items for systematic review and meta-analysis guidelines. Data of distraction frequency, number of distractions, distracted length, Cobb angle, kyphosis, T1–T12 length, and T1–S1 length preoperatively, postoperatively, and at final follow-up were collected. Data regarding complications and unplanned reoperations were also extracted. The mean values of these parameters were calculated, or pooled meta-analysis was performed if available. Ten articles were included in this systematic review, with a total of 116 patients and a follow-up period between 23 and 61 months. The mean preoperative Cobb angle and kyphosis angle were 60.1° and 38.0°, respectively, and improved to 35.4° and 26.1° postoperatively. At final follow-up, the Cobb and kyphosis angles were maintained at 36.9° and 36.0°, respectively. The average preoperative T1–T12 and T1–S1 lengths were 180.6 mm and 293.6 mm, respectively, and increased to 198.3 mm and 320.3 mm postoperatively. T1–T12 and T1–S1 lengths were 212.3 mm and 339.3 mm at final follow-up, respectively. The overall rate of patients with complications was 48% (95% confidence interval [CI], 0.38–0.58) and unplanned reoperation 44% (95% CI, 0.33–0.55) after sensitivity analysis. The current evidence from different countries with a minimum of a 2-year follow-up suggests that magnetically controlled growing rods are an effective technique to treat pediatric scoliosis and promote spine growth. However, nearly half of patients still developed complications or required unplanned reoperations.

Prevalence, Patterns, and Genetic Association Analysis of Modic Vertebral Endplate Changes

STUDY DESIGN: A prospective genetic association study. PURPOSE: The etiology of Modic changes (MCs) is unclear. Recently, the role of genetic factors in the etiology of MCs has been evaluated. However, studies with a larger patient subset are lacking, and candidate genes involved in other disc degeneration phenotypes have not been evaluated. We studied the prevalence of MCs and genetic association of 41 candidate genes in a large Indian cohort. OVERVIEW OF LITERATURE: MCs are vertebral endplate signal changes predominantly observed in the lumbar spine. A significant association between MCs and lumbar disc degeneration and nonspecific low back pain has been described, with the etiopathogenesis implicating various mechanical, infective, and biochemical factors. METHODS: We studied 809 patients using 1.5-T magnetic resonance imaging to determine the prevalence, patterns, distribution, and type of lumbar MCs. Genetic association analysis of 71 single nucleotide polymorphisms (SNPs) of 41 candidate genes was performed based on the presence or absence of MCs. SNPs were genotyped using the Sequenome platform, and an association test was performed using PLINK software. RESULTS: The mean age of the study population (n=809) was 36.7±10.8 years. Based on the presence of MCs, the cohort was divided into 702 controls and 107 cases (prevalence, 13%). MCs were more commonly present in the lower (149/251, 59.4%) than in the upper (102/251, 40.6%) endplates. L4–5 endplates were the most commonly affected levels (30.7%). Type 2 MCs were the most commonly observed pattern (n=206, 82%). The rs2228570 SNP of VDR (p=0.02) and rs17099008 SNP of MMP20 (p=0.03) were significantly associated with MCs. CONCLUSIONS: Genetic polymorphisms of SNPs of VDR and MMP20 were significantly associated with MCs. Understanding the etiopathogenetic mechanisms of MCs is important for planning preventive and therapeutic strategies.

Decompression without Fusion for Low-Grade Degenerative Spondylolisthesis

STUDY DESIGN: Retrospective series. PURPOSE: Assess results of decompression-only surgery for low-grade degenerative spondylolisthesis with consideration of instability. OVERVIEW OF LITERATURE: There is no consensus on whether fusion or decompression-only surgery leads to better outcomes for patients with low-grade degenerative spondylolisthesis. Current trends support fusion but many studies are flawed due to over-generalization without consideration of radiological instability and their variable presentations and natural history. METHODS: Patients with surgically treated degenerative spondylolisthesis from 1990-2013 were included. Clinical and radiological instability measures were included. Any residual or recurrence of symptoms, revision surgery performed and functional outcome scores including the numerical global rate of change scale, visual analogue scale, and modified Barthel index were measured. Follow-up periods for patients were divided into short-term (10 years). RESULTS: A total of 64 patients were recruited. Mechanical low back pain was noted in 48 patients and most (85.4%) had relief of back pain postoperatively. Radiological instability was noted in 4 subjects by flexion-extension radiographs and 12 subjects with prone traction radiographs by increased disc height and reduction of olisthesis and slip angle. From the results of the short-term, mid-term and long-term follow-up, reoperation only occurred within the first 5-year follow-up period. All functional scores improved from preoperative to postoperative 1-year follow-up. CONCLUSIONS: Decompression-only for low-grade degenerative spondylolisthesis has good long-term results despite instability. Further higher-level studies should be performed on this patient group with radiological instability to suggest the superior surgical option.