Results of Dual Growing Rods Treatment for Progressive Pediatric Spinal Deformity

STUDY DESIGN: A prospective study. OBJECTIVES: To report the results of new designed dual growing rods system for progressive pediatric spinal deformity. SUMMARY OF LITERATURE REVIEW: The current expandable spinal implant system appears effective in controlling progressive pediatric spinal deformity, allowing for spinal growth. However, there was no report concerning the growing rod in Korea. MATERIALS AND METHODS: Between 2010 and 2011, seven pediatric patients, who had a minimum of 1year follow-up, had undergone surgery for spinal deformity correction with a dual growing rods technique. We analyzed the demographic and radiologic data, including height, weight, age at surgery, diagnosis, number of lengthening, Cobb's angle of the major curve, thoracic kyphosis angle, lumbar lordosis angle, T1-S1 length, instrumented segment length, and complications, from the preoperative period to the last follow up period. RESULTS: Four male and three female patients with 5 neuromuscular scoliosis, 1 idiopathic juvenile osteoporosis and 1 spondyloepiphyseal dysplasia had underwent corrective surgery with dual growing rods. The mean age at the initial surgery was 11.6 years (7-13.8). The mean follow-up duration was 19.3 months (12-24), and the mean lengthening procedure time was 2.8 (2-4) for every patient. Cobb's angle of scoliosis curve was corrected from preoperative 80.2degrees(55-136) to 37.6degrees (15-81) on the last follow-up. Thoracic kyphosis angle and lumbar lordosis angle were changed from preoperative 48.7degrees(12-101) and 38.3degrees(9-72) to 44.5degrees(12-75) and 18.8degrees(1-46) on the last follow-up, respectively. Growth length during the follow-up period was measured as instrumented segment is 46 mm (33-59) and T1-S1 segment is 82 mm (66-98). Complications, such as breakage of rod in 3 cases and soft tissue infection in 1 case, occurred during the follow-up period. CONCLUSIONS: New designed dual growing rods system for pediatric patients with progressive spinal deformity is an effective and relatively safe method because of adequate correction and acceptable rate of complications.

Analysis of Single Nucleotide Polymorphism in Adolescent Idiopathic Scoliosis in Korea: For Personalized Treatment

PURPOSE: The incidence of adolescent idiopathic scoliosis (AIS) has rapidly increased, and with it, physician consultations and expenditures (about one and a half times) in the last 5 years. Recent etiological studies reveal that AIS is a complex genetic disorder that results from the interaction of multiple gene loci and the environment. For personalized treatment of AIS, a tool that can accurately measure the progression of Cobb's angle would be of great use. Gene analysis utilizing single nucleotide polymorphism (SNP) has been developed as a diagnostic tool for use in Caucasians but not Koreans. Therefore, we attempted to reveal AIS-related genes and their relevance in Koreans, exploring the potential use of gene analysis as a diagnostic tool for personalized treatment of AIS therein. MATERIALS AND METHODS: A total of 68 Korean AIS and 35 age- and sex-matched, healthy adolescents were enrolled in this study and were examined for 10 candidate scoliosis gene SNPs. RESULTS: This study revealed that the SNPs of rs2449539 in lysosomal-associated transmembrane protein 4 beta (LAPTM4B) and rs5742612 in upstream and insulin-like growth factor 1 (IGF1) were associated with both susceptibility to and curve severity in AIS. The results suggested that both LAPTM4B and IGF1 genes were important in AIS predisposition and progression. CONCLUSION: Thus, on the basis of this study, if more SNPs or candidate genes are studied in a larger population in Korea, personalized treatment of Korean AIS patients might become a possibility.

Video-Assisted Thoracoscopic Surgery Plus Lumbar Mini-Open Surgery for Adolescent Idiopathic Scoliosis

PURPOSE: The objectives of this study are to describe the outcome of adolescent idiopathic scoliosis (AIS) patients treated with Video Assisted Thoracoscopic Surgery (VATS) plus supplementary minimal incision in the lumbar region for thoracic and lumbar deformity correction and fusion. MATERIALS AND METHODS: This is a case series of 13 patients treated with VATS plus lumbar mini-open surgery for AIS. A total of 13 patients requiring fusions of both the thoracic and lumbar regions were included in this study: 5 of these patients were classified as Lenke type 1A and 8 as Lenke type 5C. Fusion was performed using VATS up to T12 or L1 vertebral level. Lower levels were accessed via a small mini-incision in the lumbar area to gain access to the lumbar spine via the retroperitoneal space. All patients had a minimum follow-up of 1 year. RESULTS: The average number of fused vertebrae was 7.1 levels. A significant correction in the Cobb angle was obtained at the final follow-up (p = 0.001). The instrumented segmental angle in the sagittal plane was relatively well-maintained following surgery, albeit with a slight increase. Scoliosis Research Society-22 (SRS-22) scores were noted have significantly improved at the final follow-up (p < 0.05). CONCLUSION: Indications for the use of VATS may be extended from patients with localized thoracic scoliosis to those with thoracolumbar scoliosis. By utilizing a supplementary minimal incision in the lumbar region, a satisfactory deformity correction may be accomplished with minimal post-operative scarring.

Comparison between Operated Muscular Dystrophy and Spinal Muscular Atrophy Patients in terms of Radiological, Pulmonary and Functional Outcomes

STUDY DESIGN: Retrospective comparative study. PURPOSE: To study and compare the surgical outcomes of muscular dystrophy (MD) and spinal muscle atrophy (SMA). OVERVIEW OF LITERATURE: There are few reports that have evaluated and compared the surgical outcomes of MD and SMA patients. METHODS: The patients (n = 35) were divided into two groups: a MD group with 24 patients and a SMA group with 11 patients. The average follow-up period was 21 months. All patients were operated for scoliosis correction using posterior instrumentation and fusion. In the immediate postoperative period, all efforts were made to reduce the pulmonary complications using non-invasive positive pressure ventilation and a coughing assist devices. The patients were evaluated by radiograph in terms of the Cobb's angle, pelvic obliquity, T1 translation, thoracic kyphosis and lumbar lordosis. The pulmonary function and self-image satisfaction were also assessed. RESULTS: There was a lower correction rate in the MD group (41.5%) than in the SMA group (48.3%), even though the curves were smaller in the MD group. The correction in the pelvic obliquity was significantly better in the SMA group (p = 0.03). The predicted vital capacity showed a 4% reduction in the MD group 1 year after surgery, while the SMA group showed a 10% reduction. The peak cough flow and end tidal PCO2 did not deteriorate and were well maintained. The average score for the improvement in self-image satisfaction postoperatively was 3.96 and 4.64 for the MD and SMA groups, respectively. The total complication rate was 45.7%; 14.3% of which were respiratory-related. CONCLUSIONS: Surgical intervention for MD and SMA may be performed safely in patients with a very low forced vital capacity (< 30%) through aggressive preoperative and postoperative rehabilitation efforts.

Comparison of Mechanical Property of Conventional Rods versus Growing Rods for Pediatric Early Onset Scoliosis

STUDY DESIGN: This is a mechanical study. OBJECTIVES: We wanted to investigate the mechanical properties of newly developed dual growing rods for obtaining approval for their clinical application. SUMMARY OF LITERATURE REVIEW: The current expandable spinal implant system appears effective for controlling progressive early onset scoliosis, and it allows for spinal growth and improving lung development. MATERIALS AND METHODS: We investigate the yield load and ultimate load during compression, tension and torsion of the growing rods and the conventional rods assembly using UHMWPE blocks, and the diameter of the rods was 6.0 mm and they expanded 5cm long. We also performed a fatigue test with growing rods, and the diameter of which was 6.0 mm and it expanded 2.5cm long. The guideline for the American Society for Testing Materials was followed during the entire mechanical test. With the growing rods and conventional rods, we tested for each mechanical property7 times with the new rods and blocks. RESULTS: The yield load of the growing rods and conventional rods were 845.2+/-18.2 (N) and 812.9+/-29.9 (N), respectively, and the ultimate load of the growing rods and conventional rods were 961.9+/-31.1 (N) and 914.9+/-25.6 (N), respectively, when compression force was applied. The yield load and ultimate load of the growing rods were statistically higher than those of the conventional rods (p0.05). The yield loads of the growing rods and conventional rods were 11.56+/-0.59 (Nm) and 12.46+/-0.71 (Nm), respectively, the ultimate loads of the growing rods and conventional rods were 16.97+/-0.94 (Nm) and 17.42+/-2.66 (Nm) during the torsion, respectively. The yield load and ultimate load of the growing rods were statistically lower than that of the conventional rods (p<0.05). CONCLUSIONS: The newly developed growing rods have a higher yield load and ultimate load under compression, a similar ultimate load under tension and a lower yield load and ultimate load under torsion. The differences of the yield load and ultimate load under torsion were minimal, and so the growing rods and conventional rods have similar mechanical properties.