Abstract. Aims. Vertebral body tethering (VBT) is a non-fusion technique to correct scoliosis allowing correction of scoliosis through growth modulation (GM) by tethering the convex side to allow concave unrestricted growth similar to the hemiepiphysiodesis concept. The other modality is anterior scoliosis correction (ASC) where the tether is able to perform most of the correction immediately where limited growth is expected. Methods. A retrospective analysis of 20 patients (M:F=19:1 – 9–17 years) between January 2014 to December 2016 with a mean five-year follow-up (4 to 7). Results. There were ten patients in each group with a total of 23 curves operated upon. VBT-GM mean age −12.5 years (9 to 14), mean Risser of 0.63 (0 to 2) and VBT-ASC was 14.9 years (13 to 17) and mean Risser of 3.66 (3 to 5). Mean preoperative VBT-GM Cobb was 47.4° (40°–58°) compared to VBT-ASC 56.5° (40°–79°). Postoperative VBT-GM Cobb was 20.3° and VBT-ASC was 11.2°. The early postoperative correction rate was 54.3% versus 81% whereas Fulcrum Bending Correction Index (FBCI) was 93.1% vs 146.6%. Latest Cobb angle at mean five years' follow-up was 19.4° (VBT-GM) and 16.5° (VBT-ASC). Overall, 5% of patients required fusion. Conclusion. We show a high success rate (95%) in helping children avoid fusion at five years post-surgery. VBT is a safe technique for scoliosis correction in the skeletally immature patient. This is the first report at five years showing two possible options of VBT depending on the skeletal maturity of the patient: GM and ASC

Abstract. Objective. Flexible stabilisation has been utilised to maintain spinal mobility in patients with early-stage lumbar spinal stenosis (LSS). Previous literature has not yet established any non-fusion solution as a viable treatment option for patients with severe posterior degeneration of the lumbar spine. This feasibility study evaluates the mean five-year outcomes of patients treated with the TOPS (Total Posterior Spine System) facet replacement system in the surgical management of lumbar spinal stenosis and degenerative spondylolisthesis. Methods. Ten patients (2 males, 8 females, mean age 59.6) were enrolled into a non-randomised prospective clinical study. Patients were evaluated with standing AP, lateral, flexion and extension radiographs and MRI scans, back and leg pain visual analog scale (VAS) scores, Oswestry Disability Index (ODI), Zurich Claudication Questionnaire (ZCQ) and the SF-36 questionnaires, preoperatively, 6 months, one year, two years and latest follow-up at a mean of five years postoperatively (range 55–74 months). Flexion and extension standing lumbar spine radiographs were obtained at 2 years to assess range of motion (ROM) at the stabilised segment. Results. The clinical outcome scores for the cohort improved significantly across all scoring systems. Radiographs at 2 years did not reveal any loss of position or loosening of metal work. There were two incidental durotomies and no failures at 5 years with no patient requiring revision surgery. Conclusions. The TOPS implant maintains clinical improvement and motion in the surgical management of LSS and spondylolisthesis, indicating it can be considered an option for these indications

Purpose of study. The aim is to assess the use of non-fusion instrumentation “growth rods” in early onset scoliosis (EOS). Methods. A retrospective review of 12 consecutive patients who had undergone a growth rod procedure for EOS was performed. Six patients had neuromuscular scoliosis, 5 had juvenile idiopathic scoliosis while one had a congenital aetiology. Growth constructs were predominately constructed from modular commercially available sets using hooks, screws and connection blocks. One VEPTR was used in a severe kyphoscoliosis. Patients returned to theatre at 6 monthly intervals for a lengthening procedure. Patients were assessed with regards to age at presentation, age at surgery, indications for surgery, initial Cobb angle, post- operative Cobb angle, number of lengthening's done, instrumentation used, amount of spine growth achieved and complications. Results. The average age at presentation was 3 yrs 8 months (birth – 7 years 5 months). The average Cobb angle was 55 (38–90). Age at index surgery ranged from 2yrs 9 months to 8 years 2 months. The Cobb angle after the first procedure averaged 37 (range 20–90). The average lengthening over 51 lengthening procedures was 8 mm. Four patients have reached the end of the process and under gone a definitive fusion with pedicle screws and growth rods. Their final Cobb angle averaged 32 (26–48). Definitive surgery was performed earlier than planned in one patient due to repetitive rod breakage. Lengthening was abandoned in one patient whose implants became septic and required removal. Two patients required revision for superior construct failure. Conclusion. The growth rod procedure allows spinal deformity correction and control as well as on-going growth in trunk height. It is a labour intensive process with a significant incidence of complications. There is however very little choice in these patients due to concerns of fusion restricting pulmonary development. NO DISCLOSURES

The emerging of non-fusion surgery is aimed to solve the long-term complication of fusion surgery that may bring the adjacent disc degeneration. Among several kinds of artificial discs developed in these years, the majority in the market is Prodisc-L (Synthes Inc.) which is designed with the purpose to restore the motions including anteroposterior translation, lateral bending, and axial rotation. These is also one artificial disc called Physio-L (Nexgen Spine) which were hyper-elastic material (Polycarbonate Polyurethanes) and is designed to restore the motions maintioned above plus axial loading. The concept of using hyper-elastic material as disc is to mimic the material properties of intervetebral discs so that this disc both absorb the axial loading and also restore the physiological range of motion. Few studies focused on the biomechanical behavior of hyper-elastic artificial discs have yet been reported. Therefore, the purpose of this study is to compare the biomechanical behavior between Prodisc-L and Physio-L. A validated three-dimensional finite element model of the L1-L5 lumbar intact spine was used in this study with ANSYS software [Fig.1]. Total disc replacement surgery, partial discectomy, total nuclectomy and removal of the anterior longitudinal ligament were performed at the L3/L4 segment of this intact model, and the Prodisc-L and Physio-L was implanted into L3/L4 segment, respectively. In addition, hyper-elastic materials adopted by Physio-L are usually categorized by their hardness into soft and hard [Fig.2]. Therefore, two kinds of Physio-L were studied. A 400 N follower load and a 10 N-m moment were applied to the intact model to obtain four physiological motions as comparison baseline. The implanted models were subjected to 400 N follower load and specific moments in accordance with the hybrid test method. For the Prodisc-L model in the surgical segment, the range of motion (ROM) varied by -26%, +17%, -0.01%, and -0.04% in flexion, extension, lateral bending, and axial rotation, respectively, as compared to intact model [Fig.3]. For the Physio-L (soft) model, ROM varied by +10%, +8%, +3%, and +19% in four physiological motions, respectively. For the physio-L (hard) model, ROM varied by +1%, +8%, +1%, and +11% in four physiological motions, respectively. For the Prodisc-L model in the adjacent segments, ROM varied by +4% ∼ +10%, -2% ∼ -5%, -1% ∼ -4%, and +1% ∼ -2% in four physiological motions, respectively. For the Physio-L (soft) model, ROM varied by 0% ∼ -5%, -2% ∼ -5%, -0% ∼ -5%, and -9% ∼ -11% in four physiological motions, respectively. For the physio-L (hard) model, ROM varied by +4% ∼ -2%, +8% ∼ -5%, +1 ∼ -5%, and +11% ∼ -6% in four physiological motions, respectively. As seemed in the simulation, the behavior of Physio-L (both soft and hard) is similar to that of intact model under flexion and extension, but not in axial rotation. In addition, Physio-L (hard) model is more similar to intact model as compared to Physio-L (soft) model