Aim:. To compare the degree of deformity correction achieved using cobalt chromium versus titanium alloy rods in patients with Adolescent Idiopathic Scoliosis. Method:. A retrospective comparison of two cohorts of patients with Adolescent Idiopathic Scoliosis treated with posterior segmental pedicle screw fixation using either Titanium or Cobalt Chromium rods. The radiographs of 50 patients treated before 2009 (Ti group) and 50 patients after 2009 (CoCr group) were reviewed for changes in: Main Coronal Curvature Sagittal Balance (C7 Plumb Line) Kyphosis (T5-12). Results:. Thirteen were excluded because of incomplete radiographs. 38 patients received CoCr, 45 Ti and 4 patients received hybrid constructs. Correction rate of curves measuring >50 was significantly improved with CoCr (81% vs 69%, p=0.02). Sagittal balance was improved in both groups (CoCr 27.8, Ti 28.0 mm) but no significant difference was seen (p=0.84). Within the Ti group 12 patients moved for normal kyphosis (20–40) to abnormal (<20, >40) while 9 patients moved from abnormal to normal (p=0.66). Within the CoCr Group 10 patients were normalised while only 2 patients moved from normal to abnormal (p=0.04). Mean change in kyphosis showed a trend towards improved correction with CoCr (4.2 vs 2.9) but failed to reach significance (p=0.62). Discussion:. We have demonstrated that CoCr rods significantly improve coronal correction in patient with >50 curves. No difference in overall sagittal balance was seen between metal alloys. There is a trend towards better restoration of T5-12 kyphosis with CoCr however it is unclear if this small difference is clinically relevant. Conflict Of Interest Statement: No conflict of interest

Introduction:. Due to absence of fusion in guided-growth devices for EOS (growing rods, Shilla, LSZ) movement of the rods against their attachment is possible resulting in wear debris formation. It is important to understand the wear resistance of materials used in these devices under appropriate conditions. Aim:. The aim of our work was to investigate wear resistance of titanium alloy Ti-6Al-4V and superelastic Nitinol. Nitinol has been used recently for correcting scoliosis and may provide a better and more gradual correction than other materials. Methodology:. Wear tests were conducted using pin-on-disc configuration in diluted calf serum, as required by ISO 18192 for spinal devices. Pins were made of titanium alloy Ti-6Al-4V and Nitinol (simulation of rods material). All discs were made of Ti6-Al-4V alloy. Results and Discussion:. Superelastic Nitinol has better wear resistance since its volume wear loss is 100 times less than that of Ti-6Al-4V. However volumetric loss from Nitinol/Ti-6Al-4V friction pair (sum of both components) was found to be just about 3 times less in comparison with Ti-6Al-4V/Ti-6Al-4V pair due to wear of the titanium component. Deposition of ceramic coatings of titanium nitride (TiN) and diamond like carbon (DLC) significantly improves the wear resistance of Nitinol/Ti-6Al-4V friction pair due to effective protection of Ti-6Al-4V alloy component from the wear damage. Wear of Nitinol used for spinal rods is not expected to be as great as the wear of titanium, additionally it is possible to reduce the wear of Nitinol/titanium combination further by using coatings on the titanium alloy. Conflict Of Interest Statement: No conflict of interest

Aims

The aim of this study was to investigate the incidence and characteristics of instrumentation failure (IF) after total en bloc spondylectomy (TES), and to analyze risk factors for IF.

Aims

To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod.

To determine the current practice of scoliosis surgery in the UK. A 10 point questionnaire was constructed to identify the philosophy of surgeons on various aspects of scoliosis surgery such as choice of implant, bone graft, autologous blood transfusion (ABT), cord monitoring and computer assisted surgery. Results are compared with the current best evidence. Consultants and Fellows attending the 2009 British Scoliosis Society meeting. 50 questionnaires were completed: 45 Consultants and 5 Fellows. All pedicle screw construct favored by 25/50, hybrid 24/50 (one undecided). Posterior construct of less than 10 levels, 20/50 would not cross-link, 11/50 used one and 19/20 used two or more. More than ten levels 17/50 considered cross-links unnecessary, 4/50 used one and 29/50 used two or more. 88% preferred titanium alloy implants, while a mixture of stainless steel and cobalt chrome was used by others. For bone graft, substitutes (24), iliac crest (14), allograft (12) and demineralised bone matrix (9) in addition to local bone. 10/50 would use recombinant bone morphogenetic protein (3 for revision cases only). 39/50 routinely used intra-operative cell salvage or ABT drains and 4/50 never used autologous blood. All used cord monitoring, Sensory (19/50), Motor (2/50) and combined (29/50). None used computer-aided surgery. 26 operated alone 12 operated in pairs and 12 varied depending on type of case. This survey has brought to light interesting variations in scoliosis surgery in UK. It may reflect the conflicting evidence in the literature

Aims

The aim of this study was to compare the peak pull-out force (PPF) of pedicle-lengthening screws (PLS) and traditional pedicle screws (TPS) using instant and cyclic fatigue testing.