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

The main form of treatment of a chordoma of the mobile spine is total en bloc spondylectomy (TES), but the clinical results are not satisfactory. Stand-alone carbon ion radiotherapy (CIRT) for bone and soft-tissue sarcomas has recently been reported to have a high rate of local control with a low rate of local recurrence.

We report two patients who underwent TES after CIRT for treating a chordoma in the lumbar spine with good medium-term outcomes. At operation, there remained histological evidence of viable tumour cells in both cases. After the combination use of TES following CIRT, neither patient showed signs of recurrence at the follow-up examination. These two cases suggest that CIRT should be combined with total spondylectomy in the treatment of chordoma of the mobile spine.

Cite this article: Bone Joint J 2013;95-B:1392–5.

Introduction. Tomita En-bloc spondylectomy (TES) of L5 is one of the most challenging spinal surgical techniques. A 42-year-old female was referred with low back pain and L5 radiculopathy with background of right shoulder excision of liposarcoma. CT-PET confirmed a solitary L5 oligometastasis. MRI showed thecal sac indentation and therefore was not suitable for stereotactic ablative radiotherapy (SABR) alone. Planning Methodology. First Stage: Carbon fibre pedicle screws were planned from L2 to S2AI-Pelvis, aligned to her patient-specific rods. Custom 3D-printed navigation guides were used to overcome challenging limitations of carbon instruments. Radiofrequency ablation (RFA) of L5 pedicles prior to osteotomy was performed to prevent sarcoma cell seeding. Microscope-assisted thecal sac-tumour separation and L5 nerve root dissection was performed. Novel surgical navigation of the ultrasonic bone cutter assisted inferior L4 and superior S1 endplate osteotomies. Second stage: We performed a vascular-assisted retroperitoneal approach to L4-S1 with protection of the great vessels. Completion of osteotomies at L4 and S1 to en-bloc L5: (L4 inferior endplate, L4/5 disc, L5 body, L5/S1 disc and S1 superior endplate). Anterior reconstruction used an expandable PEEK cage obviating the need for a third posterior stage. Reinforced with a patient-specific carbon plate L4-S1 promontory. Sacrifice of left L5 nerve root undertaken. Results. Patient rehabilitated well and was discharged after 42 days. Patient underwent SABR two months post-operatively. Despite left foot drop, she was walking independently 9 months post-operatively. Conclusion. These challenging cases require a truly multi-disciplinary team approach. We share this technique for a dual stage TES and metal-free construct with post adjuvant SABR for maximum local control

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

Purpose. We present results of high intensity focussed ultrasound (HIFU) therapy on 2 patients with recurrent sacrococcygeal chordoma with the aim to promote recruitment of patients into a larger clinical trial. Method. Extracorporeal high intensity focussed ultrasound, outcome measure: radiological evidence of involution, clinical status at follow up. Sacrococygeal chordomas are rare, histologically benign tumours that tend to grow inexorably causing pain, and loss of function in the lower limbs and genitor-urinary symptoms. Results after surgical resection with conventional radiotherapy have been generally disappointing. Carbon ion therapy has been reported to be more successful, but this is not available in the UK. Both patients presented some years after surgical resection with recurrent sacral chordoma, causing intractable pain, and declining mobility. The patients underwent several (4 and 2) sessions of HIFU, using a protocol adapted for renal cell carcinoma and without any adverse events. Follow up MRI 2 weeks and 3 months post procedure showed reduction in tumour enhancement in targeted areas. This correlated with a patient-reported improvement in pain control and improving lower limb function sustained during a 3 month period. We propose the establishment of a clinical trial examining the utility of HIFU on recurrent sacral/coccygeal chordoma in adults after surgical resection. The outcomes measured will be pain scores, functional status using validated scoring scales to allow systematic comparisons with other treatments, and survival. We aim to recruit at least 14 patients initially. Side-effects and complications of the treatment will be recorded. Treatment and follow up of patients will take place in the Churchill Hospital, Oxford, UK

Study Design. Single surgeon prospective cohort with radiological follow-up. Background. Anjarwalla et al. have shown that the addition of posterior pedicle supplementation without posterolateral fusion during an ALIF procedure significantly increases the rate of interbody fusion when using a carbon fibre / PEEK cage packed with autogenous iliac crest graft. Stand alone ALIF cages which utilise screws passing through the interbody cage and into the vertebral bodies were designed to obviate the need for a posterior procedure by increasing the anterior construct stability and fusion rate. Objective. To assess the effect of posterior pedicle screw supplementation without posterolateral fusion on the fusion rate of ALIF when using anterior cage and screw constructs. Method. Between 2003 and 2008 91 patients underwent ALIF procedure under a single surgeon for low back pain associated with degenerative disc disease or lytic spondylolisthesis. Routine CT was performed at around 1 to 2 years follow up to ensure union prior to discharge. It was noted that there was a significant number of locked pseudathroses, especially in 2 level cases, and in 2006 the surgeon started to perform simultaneous supplementary posterior pedicle screw stabilisation without posterolateral fusion in the majority of cases. Results. Of the 91 patients, 77 (85%) had CT follow up at mean 21 months. 45 patients had anterior surgery alone (26 single level and 19 two level) and 32 had front back surgery (15 single level and 17 two level). Pseudarthrosis was seen in 16 patients (36%) of the anterior alone group and 2 (6%) of the front back group. In the anterior alone group, pseudarthosis occurred in 6 / 26 (23%) patients with single level surgery and 10 /19 (53%) of those with two level surgery. In this last group, the pseudarthosis occurred in the upper fusion level in five patients and at both fusion levels in other five. Conclusion. Posterior pedicle screw supplementation without posterolateral fusion improves the fusion rate of ALIF when using anterior cage and screw constructs. We would recommend supplementary posterior fixation especially in cases where more than one level is being operated

Aims

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

Aims

Inflammatory response plays a pivotal role in the pathophysiological process of intervertebral disc degeneration (IDD). A20 (also known as tumour necrosis factor alpha-induced protein 3 (TNFAIP3)) is a ubiquitin-editing enzyme that restricts nuclear factor-kappa B (NF-κB) signalling. A20 prevents the occurrence of multiple inflammatory diseases. However, the role of A20 in the initiation of IDD has not been elucidated. The aim of the study was to investigate the effect of A20 in senescence of TNF alpha (TNF-α)-induced nucleus pulposus cells (NPCs).

Aims

We aimed to retrospectively assess the accuracy and safety of CT navigated pedicle screws and to compare accuracy in the cervical and thoracic spine (C2-T8) with (COMB) and without (POST) prior anterior surgery (anterior cervical discectomy or corpectomy and fusion with ventral plating: ACDF/ACCF).

Mesenchymal stem-cell based therapies have been proposed as novel treatments for intervertebral disc degeneration, a prevalent and disabling condition associated with back pain. The development of these treatment strategies, however, has been hindered by the incomplete understanding of the human nucleus pulposus phenotype and by an inaccurate interpretation and translation of animal to human research. This review summarises recent work characterising the nucleus pulposus phenotype in different animal models and in humans and integrates their findings with the anatomical and physiological differences between these species. Understanding this phenotype is paramount to guarantee that implanted cells restore the native functions of the intervertebral disc.

Cite this article: Bone Joint Res 2013;2:169–78.