The current study aims to compare the clinico radiological outcomes between Non-Fusion Anterior Scoliosis (NFASC) Correction and Posterior Spinal Fusion (PSF) for Lenke 5 curves at 2 years follow up. Methods:38 consecutive Lenke 5 AIS patients treated by a single surgeon with NFASC (group A) or PSF (group B) were matched by age, Cobb's angle, and skeletal maturity. Intraoperative blood loss, operative time, LOS, coronal Cobbs, and SRS22 scores at 2 years were compared. Flexibility was assessed by modified Schober's test. Continuous variables were compared using student t-tests and categorical variables were compared using chi-square. The cohort included 19 patients each in group A and B . Group A had M:F distribution of 1:18 while group B had 2:17. The mean age in group A and group B were 14.8±2.9 and 15.3±3.1 years respectively. The mean follow-up of patients in groups A and B were 24.5±1.8 months and 27.4±2.1 months respectively. Mean pre-op thoracolumbar/lumbar (TL/L) cobbs for group A and group B were 55°±7° and 57.5°±8° respectively. At two years follow up, the cobbs for group A and B were 18.2°±3.6° and 17.6°±3.5° respectively (p=0.09). The average operating time for groups A and B were 169±14.2 mins and 219±20.5 mins respectively (p<0.05). The average blood loss of groups A and B were 105.3±15.4 and 325.3±120.4 respectively (p<0.05). The average number of instrumented vertebra between groups A and B were 6.2 and 8.5 respectively (p<0.05). The average LOS for NFASC and PSF was 3.3±0.9 days and 4.3±1.1 days respectively (p<0.05). No statistically significant difference in SRS 22 score was noted between the two groups. No complications were recorded. Our study shows no significant difference in PSF and NFASC in terms of Cobbs correction and SRS scores, but the NFASC group had significantly reduced blood loss, operative time, and fewer instrumented levels. NFASC is an effective alternative technique to fusion to correct and stabilize Lenke 5 AIS curves with preservation of spinal motion

Background. For dorsal stabilization, rigid implant systems are be coming increasingly complemented by numerous dynamic systems based on pedicle screws. Numerous posterior non-fusion systems have been developed within the past decade to resolve the disadvantages of rigid instrumentations and preserve spinal motion. For dorsal stabilization, rigid implant systems are becoming increasingly complemented by numerous dynamic systems based on pedicle screws and varying direction. However, it is still unclear which direction is most suitable to accomplish a physiologically related dynamic stabilization, and which loadings conditions are induced to the implants. Purpose. The aim of this study was to investigate the effect of a new telescopic dynamic stabilization device. Evaluation of the effects on the dynamic stabilization of the spine in terms of segmental range of motion (RoM), and implant loadings. Methods. Six sheep lumbar spine motion segments (L3–4) were loaded in a spine tester with pure moments of 7.5 Nm in flexion/extension lateral bending right/left. Specimens were tested in groups of intact (1), facetectomy with rigid fixation (2), facetectomy with the new telescopic mobil stabilization device (3). The kinematic response was recorded using an opto electric tracking system and reported in terms of intervertebral range of motion (ROM) and spinal stability. Results. Mobile rod's kinematical behavior is more closer to intact group than rigid fixation. Flexion: 3.6 mm, 3.93 mm and 1.81 mm; extension 3.79 mm, 3.84 mm and 2.27 mm; lateral bending right 3.64 mm, 4.39 mm and 2.47 mm; lateral bendig left 4.6 mm and 5.79 mm and 2.58 mm, respectively. Conclusion. Those involved in the design and evaluation of telescopic mobil rod devices may benefit from evaluation of inter pedicular kinematics. Evaluating inter vertebral motion from the perspective of the pedicle screw allows for a direct and intuitive translation between in vitro test results and design parameters. Furthermore, telescopic mobile rod knematics were similar to intact spine

Background. Using flexible tethering techniques, porcine models of scoliosis have been previously described. These scoliotic curves showed vertebral wedging but very limited axial rotation. In some of these techniques, a persistent scoliotic deformity was found after tether release. The possibility to create severe progressive true scoliosis in a big animal model would be very useful for research purposes, including corrective therapies. Methods. The experimental ethics committee of the main institution provide the approval to conduct the study. Experimental study using a growing porcine model. Unilateral spinal bent rigid tether anchored to two ipsilateral pedicle screws was used to induce scoliosis on eight pigs. Five spinal segments were left between the instrumented pedicles. The spinal tether was removed after 8 weeks. Ten weeks later the animals were sacrificed. Conventional radiographs and 3D CT-scans of the specimens were taken to evaluate changes in the coronal and sagittal alignment of the thoracic spine. Fine-cut CT-scans were used to evaluate vertebral and disc wedging and axial rotation. Results. After 8 weeks of rigid tethering, the mean Cobb angle of the curves was 24.3 ± 13.8 degrees. Once the interpedicular tether was removed, the scoliotic curves progressed in all animals until sacrifice. During these 10 weeks without spinal tethering the mean Cobb angle reached 50.1 ± 27.1 degrees. The sagittal alignment of the thoracic spine showed loss of physiologic kyphosis. Axial rotation ranges from 10 to 35 degrees. There was no auto-correction of the curve in any animal. A further pathologic analysis of the vertebral segments revealed that animals with greater progression had more damage of the neurocentral cartilages and epiphyseal plates at the sites of pedicle screw insertion. Interestingly, in these animals with more severe curves, compensatory curves were found proximal and distal to the tethered segments. Conclusions. Temporary interpedicular tethering at the thoracic spine induces severe scoliotic curves in pigs, with significant wedging and rotation of the vertebral bodies. As detailed by CT morphometric analysis, release of the spinal tether systematically results in progression of the deformity with development of compensatory curves outside the tethered segment. The clinical relevance of this work is that this tether release model will be very useful to evaluate both fusion and non-fusion corrective technologies in future research. Level of Evidence. Not apply for experimental studies

Growth rods are currently used in young children to hold a scoliosis until the spine has reached a mature length. Only partial deformity correction is achieved upon implantation, and secondary surgeries are required at 6-12 month intervals to lengthen the holding rod as the child grows. This process contains, rather than corrects, the deformity and spinal fusion is required at maturity. This treatment has a significant negative impact on the bio-psychosocial development of the child. Aim. To design a device that would provide a single minimally invasive, non-fusion, surgical solution that permits controlled spinal movement and delivers three dimensional spinal correction. Method. Physical and CAD implant models were developed to predict curve and rotational correction during growth. This allowed use of static structural finite element analysis to identify magnitudes and areas of maximum stress to direct the design of prototype implants. These were mechanically tested for strength, fatigue and wear to meet current Industrial standards. Results. A dynamic hinged construct, was produced. This consisted of carbon nitride coated CoCrMo components assembled in a modular fashion. Five implants were tested under static load to simulate spinal flexion establishing a mean average yield point at a bending moment of 20.8 Nm (SD 2.5 Nm). Six samples were tested for fatigue endurance to 10 million cycles. Two implants were loaded with a 10 Nm maximum bending moment without fracture. Two samples were loaded at 14 Nm with one surviving and one fracturing at 569,048 cycles. Samples loaded at 16 Nm and 17 Nm both fractured at 3,460,359 and 237,613 cycles respectively. Two implants were tested for wear, the first fractured after 290,000 cycles. A second modified implant was tested to ten million cycles and a mean wear rate of 2.03 mg per million cycles was determined during this period. Exposure of the CoCrMo implant substrate was first observed at two million cycles. Conclusion. The device met all mechanical test criteria necessary for CE marking and allowed progression to implant testing in an ovine model