Aims. We compared the clinical and radiological outcomes of using a
polyetheretherketone cage with (TiPEEK) and without a titanium coating
(PEEK) for instrumented transforaminal lumbar interbody fusion (TLIF). Materials and Methods. We conducted a randomised clinical pilot trial of 40 patients
who were scheduled to undergo a TLIF procedure at one or two levels
between L2 and L5. The Oswestry disability index (ODI), EuroQoL-5D,
and back and leg pain were determined pre-operatively, and at three,
six, and 12 months post-operatively. Fusion rates were assessed
by thin slice CT at three months and by functional radiography at
12 months. Results. At final follow-up, one patient in each group had been lost to
follow-up. Two patients in each of the PEEK and TiPEEK groups were
revised for pseudarthrosis (p = 1.00). The rate of complete or partial
fusion at three months was 91.7% in both groups. Overall, there
were no significant differences in ODI or in radiological outcomes
between the groups. Conclusion. Favourable results with identical clinical outcomes and a high
rate of fusion was seen in both groups. The titanium
We investigated the effects of hydroxyapatite (HA)
Aims. In this investigation, we administered oxidative stress to nucleus pulposus cells (NPCs), recognized DNA-damage-inducible transcript 4 (DDIT4) as a component in intervertebral disc degeneration (IVDD), and devised a hydrogel capable of conveying small interfering RNA (siRNA) to IVDD. Methods. An in vitro model for oxidative stress-induced injury in NPCs was developed to elucidate the mechanisms underlying the upregulation of DDIT4 expression, activation of the reactive oxygen species (ROS)-thioredoxin-interacting protein (TXNIP)-NLRP3 signalling pathway, and nucleus pulposus pyroptosis. Furthermore, the mechanism of action of small interfering DDIT4 (siDDIT4) on NPCs in vitro was validated. A triplex hydrogel named siDDIT4@G5-P-HA was created by adsorbing siDDIT4 onto fifth-generation polyamidoamine (PAMAM) dendrimer using van der Waals interactions, and then
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
We have studied two matching cohorts of patients treated by Dynesys flexible stabilisation with and without hydroxyapatite (HA)
Objective. From our series of 570 Dynesys flexible stabilisation procedures, we studied two prospective series of patients with a minimum one-year follow-up comparing uncoated and hydroxyapatite-coated (HA) screws. Methods. Patients were entered prospectively and followed up at 6 weeks, 3, 6, and 12 months and annually thereafter. Plain radiographs were obtained annually. 58 patients who underwent Dynesys stabilisation with HA coated screws (312 screws) were evaluated. The data was compared with 71 patients who underwent Dynesys stabilisation with non-coated pedicle screws (366 screws). Outcome measures were screw loosening, breakage, implant removal or revision. Follow up was 96 %. Results. In the HA coated group there were five screw breakages in three patients, all affecting S1 screws. There was evidence of loosening in one patient. In the non-HA coated group there were two cases of infection, both had their implants removed. Further 11 patients had screw loosening and required implant removal. There was a significant improvement of anchorage of the HA coated screws. There was no correlation between numbers of level stabilised, or previous surgery and screw loosening. Average time to revision surgery for loosening was 23 months in the non-coated group. Screw fractures occurred at 11 months in the HA coated group. There was no correlation between screw loosening or fracture and gender or age. Conclusions. Change to HA
Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques. Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S4). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads.Aims
Methods
To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod. This was a prospective observational study of patients with early onset scoliosis (EOS) treated with MCGRs and undergoing rod exchange who were consecutively recruited between February 2019 and January 2020. Ten patients were recruited (mean age 12 years (SD 1.3); 2 M:8 F). The configurations of the MCGR were studied to reveal the distraction mechanisms, with crucial rod parts being the distractable piston rod and the magnetically driven rotor inside the barrel of the MCGR. Metal-on-metal contact in the form of ring-like wear marks on the piston was found on the distracted portion of the piston immediately outside the barrel opening (BO) through which the piston rod distracts. Biopsies of paraspinal muscles and control tissue samples were taken over and away from the wear marks, respectively. Spectral analyses of the rod alloy and biopsies were performed to reveal the metal constituents and concentrations. Histological analyses of the biopsies were performed with haematoxylin and eosin staining.Aims
Methods
Between January 1990 and December 2000 we carried out 226 SB Charité III disc replacements for lumbar disc degeneration in 160 patients. They were reviewed at a mean follow-up of 79 months (31 to 161) to determine the clinical and radiological outcome. The clinical results were collected by an independent observer, who was not involved in patient selection, treatment or follow-up, using a combination of outcome measures, including the Oswestry Disability Index. Pain was recorded using a visual analogue score, and the most recent radiographs were reviewed. Survival of the device was analysed by the Kaplan-Meier method and showed a cumulative survival of 35% at 156 months when radiological failure was taken as the endpoint. The mean improvement in the Oswestry disability index scores after disc replacement was 14% (6% to 21%) and the mean improvement in the pain score was 1.6 (0.46 to 2.73), both falling below the clinically significant threshold. Removal of the implant was required in 12 patients, four because of implant failure. These poor results indicate that further use of this implant is not justified.
