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 coating appears to have no negative effects on outcome or safety in the short term. A future study to determine the effect of titanium coating is warranted. Cite this article: Bone Joint J 2017;99-B:1366–72

Background. Carbon fibre (CF) instrumentation is known to be radiolucent and has a tensile strength similar to metal. A specific use could be primary or oligometastatic cancer where regular surveillance imaging and Stereotactic Radiotherapy are required. CT images are inherently more prone to artefacts which affect Hounsfield unit (HU) measurements. Titanium (Ti) screws scatter more artefacts. Until now it has been difficult to quantify how advantageous the radiolucency of carbon fibre pedicle screws compared to titanium or metallic screws actually is. Methodology. In this retrospective study, conducted on patients from 2018 to 2020 in SGH, we measured the HU to compare the artifact produced by CF versus Ti pedicle screws and rods implanted in age and sex matched group of patients with oligometastatic spinal disease. Results. Eleven patients were included in each group. We compared the change of HU between preoperative and postoperative cases of both CF & Ti screws, which clearly shows Ti screws scatter lot more artefacts than CF screws. We are proposing a CT artefact grading system from grade 0 to grade 4 based on the percentage change of HU for unequivocal understanding of the CT artefacts. Conclusion. This study clearly shows the artefacts produced by the metallic implants are significantly higher than the carbon fibre implants. Considering the efficacy of the RT and the increased life expectancy as a consequence, carbon instrumentation MAY BE superior to titanium or metallic instrumentation. The artefact grading system will help the clinicians in describing and planning where the artefacts need to be factorized

Aim:. The aim of this study was test the amount of corrosion occurring at the (Ti) /cobalt chrome (CoCr) interface comparing this with Ti and Ti interfaces. This was compared with retrieved metal work visualised under a scanning electron microscope (SEM). Methods:. The interface of interest is the interface between rod and the screw. We investigated corrosion seen at that interface with a CoCr rod coupled to a Ti screw versus a Ti rod coupled to a Ti screw (6 screws were used) Implants were loaded according to the ASTM F2193 – 02 Standard Specifications and Test Methods for Components Used in the Surgical Fixation of the Spinal Skeletal System. Pitting potentials were monitored using cyclic potentiodynamic polarization tests (ASTM F2129 – 08 Standard Test Method for Conducting Cyclic Potentiodynamic Polarisation Measurements) to determine corrosion susceptibility. Retrieved implants were visualised under (SEM) to confirm corrosion. Results:. Mean fretting current for titanium and cobalt chrome was 7.94 (μA) and for titanium on titanium 5.89 (μA). The results of SEM showed evidence of fretting and galvanic corrosion. Discussion:. Cobalt chrome ions in hip implants have raised concern amongst the orthopaedic community. This study showed that metal ion production occurs due to fretting and galvanic corrosion. This corrosion is increased in cobalt chrome and titanium constructs but statistically more tests are required to confirm this. Further research is required to understand this interface as cobalt chrome ions pose a potential hazard to patients with their reproductive years ahead. 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

Aim. The purpose of this study is to compare the pre and post-operative magnetic resonance image clarity of titanium and PEEK based cervical arthroplasty devices at the level of implantation and adjacent level discs. Methodology and Results. This is a prospective, blinded, randomised study on imaging of cervical arthroplasty devices. The pre and postoperative MRI images of 16 patients who underwent cervical arthroplasty using Prestige LP(r) (Medtronic Sofamor Danek) and NuNec(tm) Cervical Arthroplasty System (Pioneer Surgical Technology, Marquette, Mich., USA) were assessed. Two independent radiologists who were blinded and provided with a sets of random images to score using a four point Jarvick grading system. Statistical analysis was completed using SPSS 16.0 statistical package (SPSS Inc, Chicago, IL) and analysis included comparing MR image quality before and after cervical arthroplasty at the operated and adjacent levels, and in between two types of implant. The pre-operative MR image quality at operated and adjacent levels was excellent in both groups. In the post-operative images, the adjacent level visualisation was adequate in both groups without much difference in average scores. However, at operated level, the quality of MR images in the NuNec group (PEEK on PEEK articulating disc) was excellent and clear visualisation of the cord, central canal, foramen and disc. Conclusion. Previous studies have shown that titanium devices allow satisfactory monitoring of adjacent and operated levels by providing good quality MRI images. Our studies confirm that using titanium based cervical arthroplasty implants provide clear visualisation of the adjacent level, however, provide less than satisfactory images at operated level. But the PEEK devices provide excellent quality images even at the operated level, with clear visualisation of neural structures and are valuable, if one wishes to assess the adequacy of neural decompression at operated level

Aims. To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod. Methods. 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. Results. Titanium (Ti), vanadium (V), and neodymium (Nd) concentrations in the biopsies taken near the wear marks were found to be significantly higher than those in the control tissue samples. Significantly increased Nd concentrations were also found in the tissues near the barrel of the MCGR. Chronic inflammation was revealed by the histological studies with fibrosis and macrophage infiltration. Black particles were present within the macrophages in the fibrotic tissues. Conclusion. Ti and V were generated mainly at the BO due to metal-on-metal contact, whereas the Nd from the rotor of the MCGR is likely released from the BO during distraction sessions. Phagocytotic immune cells with black particles inside raise concern regarding the long-term implications of metallosis. Cite this article: Bone Joint J 2020;102-B(10):1375–1383

Aims

The aim of this study was to report the long-term prognosis of patients with multiple Langerhans cell histiocytosis (LCH) involving the spine, and to analyze the risk factors for progression-free survival (PFS).

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The aim of this study was to compare outcomes after growth-friendly treatment for early-onset scoliosis (EOS) between patients with skeletal dysplasias versus those with other syndromes.

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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.

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The aims of this study were first, to determine if adding fusion to a decompression of the lumbar spine for spinal stenosis decreases the rate of radiological restenosis and/or proximal adjacent level stenosis two years after surgery, and second, to evaluate the change in vertebral slip two years after surgery with and without fusion.

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Surgical approaches to cervical ossification of the posterior longitudinal ligament (OPLL) remain controversial. The purpose of the present study was to analyze and compare the long-term neurological recovery following anterior decompression with fusion (ADF) and posterior laminectomy and fusion with bone graft and internal fixation (PLF) based on > ten-year follow-up outcomes in a single centre.

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The aim of this study was to reassess the rate of neurological, psoas-related, and abdominal complications associated with L4-L5 lateral lumbar interbody fusion (LLIF) undertaken using a standardized preoperative assessment and surgical technique.

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The optimal procedure for the treatment of ossification of the posterior longitudinal ligament (OPLL) remains controversial. The aim of this study was to compare the outcome of anterior cervical ossified posterior longitudinal ligament en bloc resection (ACOE) with posterior laminectomy and fusion with bone graft and internal fixation (PTLF) for the surgical management of patients with this condition.

Pedicle screw constructs (PSC) in scoliosis are a recently established and widely accepted method of managing scoliotic curves posteriorly. There is a perceived improved coronal and rotational correction when compared to other posterior only constructs. With continued use of this method, the authors and deformity surgeons in general have become aware of persistent thoracic hypokyphosis. This review of 3 years of scoliosis cases using PSC looks at four different implant strategies utilised to manage this problem and our current practice. These strategies were:. All titanium 5.5 mm rod diameter (Expedium, Depuy spine). All titanium 5.5 mm rod diameter with periapical washers (Expedium, Depuy spine). All titanium 6.0 mm rod diameter (Pangea, Synthes). Titanium pedicle screws with 5.5 mm diameter cobalt chrome rods (Expedium Depuy spine). We have reviewed our outcomes with these strategies with respect to thoracic hypokyphosis. Strategy 1 had the highest rate of hypokyphosis on postoperative radiographs. Strategy 4 seems to have the best correction of coronal and sagittal plane abnormality post operatively. As a consequence, our current practice is the use of titanium pedicle screws and 5.5 mm diameter cobalt chrome rods when managing scoliosis with a pedicle screw construct

Following studies in 2007-08 comparing cervical discs devices, satisfaction and accuracy of operated and adjacent levels was observed with titanium devices. Patients were followed up and surgical assessments recorded. MRI with 12 patients were first assessed for imaging quality. Two independent radiologists scored twice sagittal and axial T2 – weighted images using the Jarvik four point scale. Statistical analysis was performed on operated and adjacent levels and between devices. Length of surgery, blood loss, approach and time of exposure to radiation were recorded. Patients were followed up at two years. BAGUERA C containing titanium metal allowed satisfactory visualization of the canal, exit foramina, cord and adjacent levels. PCM and PRODISC C visualization was significantly impaired at operated level and in both spinal cord and neural foramina. At adjacent levels, image quality was statistically poorer for those two devices. 6 patients were operated at C5-C6 and 6 at C6-C7. Mean age was 49. Approach was from the right, length of surgery and blood loss were: mean 46 min and 16.25 cc for BAGUERA C; mean 70 min and 27.5 cc for PCM and mean 63 min with 26.25 cc for PRODISC C. Exposure to radiation presented also significant difference between devices. Clinical outcomes reveal similar VAS and patient's satisfaction scores. Titanium device with polyethylene allow for satisfactory monitoring with adequacy in the assessment of neural decompression. BAGUERA C surgical outcomes indicate potential benefits that may be related to technique and simplicity of implantation

8 patients with cervical myelopathy treated by French-door laminoplasty and internal fixation. A novel technique of fixation is employed to provide immediate stability, pain relief and rapid mobilisation. To report the clinical and radiological outcomes of this new fixation device for French–door laminoplasty with minimum follow-up of 30 months. Hardware assisted laminoplasty has the potential advantage of instant stability and prevention of recurring stenosis. The use of titanium mini-plates has been described in open-door laminoplasty and now we describe this technique in French–door laminoplasty. 8 patients with cervical myelopathy secondary to congenital stenosis (2) and multi-level spondylotic myelopathy (6) underwent 2-4 level French–door laminoplasty and mini-plate fixation. The average follow-up was 46.5 months. Autogenous iliac crest bone graft was interposed between the sagittally split spinous processes and 16-18 holed titanium mini-plates were contoured into a trapezoidal shape and secured to the posterior elements with screws. Patients then mobilised without external support. The mean follow-up was 46.5 months. The mean improvement in NDI at final follow-up was 35% and mean improvement in VAS was 4 points. JOA score improved from a mean of 10 to a mean of 14.8 post-operatively. All patients had achieved a significant neurological improvement and pain relief. There were no post-operative hardware related complications, pseudarthrosis or neurological deterioration. French-door laminoplasty is an excellent alternative to laminectomy for treatment of young patients with cervical myelopathy. The use of titanium mini-plates not only provides instant stability and pain relief but also seems to minimize the risk of C5 nerve root palsy. Internal fixation appears to provide instant stability, early mobilisation and therefore reduces hospital stay and associated costs

Introduction. With the use of each pedicle screw for surgical correction of adolescent idiopathic scoliosis (AIS), there is an increase in instrumentation-related costs, operative time, risk of neural injury, and overall health-care expenses. As such, alternate level screw strategy (ALSS) has been reported as a potential alternative to contiguous multilevel screw strategy (CMSS). Moreover, studies have shown the importance in accounting for the flexibility of the curve based on the fulcrum bending radiograph when assessing postoperative curve correction. Therefore, this study addressed a radiographic and cost analysis comparing CMSS with ALSS for the treatment of thoracic AIS with titanium screws and rod application. Methods. 77 patients with AIS underwent surgery (range 6–15 levels). 35 patients received CMSS, which was characterised as bilateral screw fixation at every level. 42 patients underwent ALSS, which entailed bilateral screw fixation at alternate levels. Titanium rods were used in all cases. Preoperative and postoperative posteroanterior and fulcrum bending radiographic Cobb angles were obtained for all patients. The fulcrum flexibility and the fulcrum bending correction index (FBCI) were assessed. Cost analysis was also done. Results. We recorded a statistically significant difference between screw strategy-type to that of preoperative and postoperative Cobb angles, and postoperative curve correction (p<0·05). No statistically significant difference was noted between screw strategy-type and fulcrum flexibility (CMSS mean 66·9%; ALSS mean 62·7%; p>0·05). The mean FBCIs of the CMSS and ALSS were 126·1% and 122·1%, respectively, and did not differ significantly (p=0·734). Compared with CMSS, ALSS was associated with pedicle screw cost reductions of up to 46·2%. Conclusions. This study is the first to show that irrespective of curve rigidity, ALSS with fewer pedicle screws can achieve comparable FBCI as CMSS. We attribute this finding to the relatively flexible titanium rods used in this study. Thus, ALSS is as effective as CMSS in terms of coronal curve correction, and it has the added benefits of reducing operative time and neurological complication risk. Furthermore, it offers the possibility of better kyphosis restoration compared with the lordosing effect of CMSS

Abstract

MAGnetic Expansion Control (MAGEC) rods are used in the surgical treatment of children with early onset scoliosis. The magnetically controlled lengthening mechanism enables rod distractions without the need for repeated invasive surgery. The CE certification of these devices was suspended in March 2021 due, primarily, to performance evidence gaps in the documents provided by the manufacturer to regulators and notified bodies. MAGEC rods are therefore not permitted for use in countries requiring CE marking. This was a survey of 18 MAGEC rod surgeons in the UK about their perception of the impact of the CE suspension on the clinical management of their patients. Unsurprisingly, virtually all perceived a negative impact, reflecting the complexity of this patient group. Reassuringly, these surgeons are highly experienced in alternative treatment methods.

Cite this article: Bone Jt Open 2022;3(2):155–157.

Aims

The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs).

Aim:. To evaluate the effect of a stiffer rod in normalising thoracic hypokyphosis in adolescent idiopathic scoliosis (AIS). Methods:. A retrospective review of AIS cases performed at our institution was carried out. In order to reduce variability, the analysis included only Lenke 1 cases which had all pedicle screw constructs, with similar constructs and implant density. Cases that underwent anterior release were excluded. All cases had the same implant (Expedium 5.5, Depuy-Synthes, Raynham, USA). The rod material differed in that some cases had 5.5 titanium, whilst others had 5.5 cobalt chrome. The preoperative and postoperative sagittal Cobb angle was measured. Results:. 35 patients met the inclusion criteria. 15 had titanium rods and 20 had cobalt chrome rods. The mean fulcrum correction index was similar between groups. The preoperative coronal and sagittal Cobb was similar between the two groups. There was no statistically significant difference in the postoperative sagittal Cobb between the two groups (ANOVA one way test). Discussion:. Despite the theoretical advantage of a stiffer construct improving the sagittal profile in AIS, this study identified no such benefit despite closely matching the two groups. All pedicle screw constructs do not seem to improve the sagittal profile despite the use of a stiffer rod. Conflict of interest:. Depuy-Synthes fund a fellow in this unit. Conflict Of Interest Statement: No conflict of interest