We have evaluated the use of a synthetic porous ceramic (Triosite) as a substitute for bone graft in posterior spinal fusion for idiopathic scoliosis. In a prospective, randomised study 341 patients at five hospitals in the UK and France were randomly allocated either to autograft from the iliac crest or rib segments (171) or to receive Triosite blocks (170). All patients were assessed after operation and at 3, 6, 12 and 18 months. The two groups were similar with regard to all demographic and baseline variables, but the 184 treated in France (54%) had Cotrel-Dubouset instrumentation and the 157 treated in the UK usually had Harrington-Luque implants. In the Triosite group the average Cobb angle of the upper curve was 56°, corrected to 24° (57%). At 18 months, the average was 26° (3% loss). In the autograft group the average preoperative upper curve of 53° was corrected to 21° (60%). At 18 months the mean curve was 25° (8% loss). Pain levels after operation were similar in the two groups, being mild in most cases. In the Triosite group only three patients had problems of wound healing, but in the autograft group, 14 patients had delayed healing, infection or haematoma in the spinal wound. In addition, 15 autograft patients had pain at the donor site at three months. Seven had infections, two had haematoma and four had delayed healing. The haematological and serum biochemistry results showed no abnormal trends and no significant differences between the groups. There were no adverse events related to the graft material and no evidence of allergenicity. Our results suggest that Triosite synthetic porous ceramic is a safe and effective substitute for autograft in these patients. Histological findings on biopsy indicate that Triosite provides a favourable scaffolding for the formation of new bone and is gradually incorporated into the fusion mass

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

We evaluated the efficacy of Escherichia coli-derived recombinant human bone morphogenetic protein-2 (E-BMP-2) in a mini-pig model of spinal anterior interbody fusion. A total of 14 male mini-pigs underwent three-level anterior lumbar interbody fusion using polyether etherketone (PEEK) cages containing porous hydroxyapatite (HA). Four groups of cages were prepared: 1) control (n = 10 segments); 2) 50 μg E-BMP-2 (n = 9); 3) 200 μg E-BMP-2 (n = 10); and 4) 800 μg E-BMP-2 (n = 9). At eight weeks after surgery the mini-pigs were killed and the specimens were evaluated by gross inspection and manual palpation, radiological evaluation including plain radiographs and micro-CT scans, and histological analysis. Rates of fusion within PEEK cages and overall union rates were calculated, and bone formation outside vertebrae was evaluated. One animal died post-operatively and was excluded, and one section was lost and also excluded, leaving 38 sites for assessment. This rate of fusion within cages was 30.0% (three of ten) in the control group, 44.4% (four of nine) in the 50 μg E-BMP-2 group, 60.0% (six of ten) in the 200 μg E-BMP-2 group, and 77.8% (seven of nine) in the 800 μg E-BMP-2 group. Fusion rate was significantly increased by the addition of E-BMP-2 and with increasing E-BMP-2 dose (p = 0.046). In a mini-pig spinal anterior interbody fusion model using porous HA as a carrier, the implantation of E-BMP-2-loaded PEEK cages improved the fusion rate compared with PEEK cages alone, an effect that was significantly increased with increasing E-BMP-2 dosage.

Cite this article: Bone Joint J 2013;95-B:217–23.