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Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_15 | Pages 22 - 22
7 Aug 2024
Saunders F Parkinson J Aspden R Cootes T Gregory J
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Background. Lateral lumbar spine statistical shape models (SSM) have been used previously to describe associations with osteoarthritis and back pain. However, associations with factors such as osteoporosis, menopause and parity have not been explored. Methods and Results. A 143-point SSM, describing L1 to the top of L5, was applied to lateral spine iDXA scans from UK Biobank. Associations with self-reported osteoporosis, menopause, parity and back pain and the first 10 modes of variation were examined using adjusted binary logistic regression or linear regression (adjusted for age, height, weight and total spine BMD). We report odds ratios with 95% confidence intervals for each standard deviation change in mode. Complete data were available for 2494 women. Mean age was 61.5 (± 7.4) years. 1369 women reported going through menopause, 96 women self-reported osteoporosis and 339 women reported chronic back pain. 80% of women reported at least 1 live birth. Lumbar spine shape was not associated with back pain in this cohort. Two modes were associated with menopause (modes 1 & 2), 1 mode with parity (mode 1) and 2 modes with osteoporosis (modes 3 & 5). Mode 1 (43.6% total variation), describing lumbar curvature was positively associated with both menopause [OR 1.15 95% CI 1.00–1.33, p=0.05] and parity [OR 1.058 95% CI 1.03–1.0, p=0.01]. Mode 3, describing decreased vertebral height was positively associated with osteoporosis [OR 1.40 95% CI 1.14–1.73, p=0.001]. Conclusion. Menopause and parity were associated with a curvier lumbar spine and osteoporosis with decreased vertebral height. Shape was not associated with back pain. No conflicts of interest.  . Sources of funding. Wellcome Trust collaborative award ref 209233


Orthopaedic Proceedings
Vol. 106-B, Issue SUPP_15 | Pages 37 - 37
7 Aug 2024
Wilson M Cole A Hewson D Hind D Hawksworth O Hyslop M Keetharuth A Macfarlane A Martin B McLeod G Rombach I Swaby L Tripathi S Wilby M
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Background. Over 55,000 spinal operations are performed annually in the NHS. Effective postoperative analgesia facilitates early mobilisation and assists rehabilitation and hospital discharge, but is difficult to achieve with conventional, opioid-based, oral analgesia. The clinical and cost-effectiveness of two alternative techniques, namely intrathecal opioid and the more novel erector-spinae plane blockade, is unknown. The Pain Relief After Instrumented Spinal Surgery (PRAISE) trial aims to evaluate these techniques. Methods. PRAISE is a multicentre, prospective, parallel group, patient-blinded, randomised trial, seeking to recruit 456 adult participants undergoing elective, posterior lumbar-instrumented spinal surgery from up to 25 NHS hospitals. Participants will be randomised 1:1:1 to receive (1) Usual Care with local wound infiltration, (2) Intrathecal Opioid plus Usual Care with local wound infiltration or (3) Erector Spinae Plane blockade plus Usual Care with no local wound infiltration. The primary outcome is pain on movement on a 100mm visual analogue scale at 24 hours post-surgery. Secondary outcomes include pain at rest, leg pain, quality of recovery (QoR-15), postoperative opioid consumption, time to mobilisation, length of hospital stay, health utility (EQ-5D-5L), adverse events and resource use. Parallel economic evaluation will estimate incremental cost-effectiveness ratios. Results. Differences in the primary outcome at 24 hours will be estimated by mixed-effects linear regression modelling, with fixed effects for randomisation factors and other important prognostic variables, and random effects for centre, using the as-randomised population. Treatment effects with 95% confidence intervals will be presented. Conclusion. The study is due to open in May 2024 and complete in 2026. Conflicts of Interest. No conflicts of interest declared. Sources of Funding. NIHR Health Technology Award – grant number NIHR153170. Trial presentations so far. APOMP 2023 and 2024; RCOA conference, York, November 2023; Faculty of Pain Management training day, London, February 2024


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_11 | Pages 25 - 25
1 Sep 2021
Shah N Shafafy R Selvadurai S Benton A Herzog J Molloy S
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Introduction. Patients with metastatic spinal cord compression (MSCC) or unstable spinal lesions warrant early surgical consultation. In multiple myeloma, chemotherapy and radiotherapy have the potential to decompress the spinal canal effectively in the presence of epidural lesions. Mechanical stability conferred by bracing may potentiate intraosseous and extraosseous bone formation, thus increasing spinal stability. This study aims to review the role of non-operative management in myeloma patients with a high degree of spinal instability, in a specialist tertiary centre. Methods. Retrospective analysis of a prospectively collected database of 83 patients with unstable myelomatous lesions of the spine, defined by a Spinal Instability Neoplastic Score (SINS) of 13–18. Data collected include patient demographics, systemic treatment, neurological status, radiological presence of cord compression, most unstable vertebral level and presence of intraosseous and extraosseous bone formation. Post-treatment scores were calculated based on follow-up imaging which was carried out at 2 weeks for cord compression and 12 weeks for spinal instability. A paired t-test was used to identify any significant difference between pre- and post-treatment SINS and linear regression was used to assess the association between variables and the change in SINS. Results. A significant reduction in SINS was observed from a pre-treatment average score of 14 to a score of 9, following treatment for myeloma (p<0.001). A higher initial score and a younger age were associated with a larger overall reduction in SINS (p<0.001 and p=0.02 respectively). No single variable (bisphosphates, chemotherapy, radiotherapy and steroids) had a significant association with SINS reduction. 25 (30%) patients had spinal cord compression, all of which showed radiological resolution of cord compression at 2 weeks. No patients developed neurological deterioration during treatment and all patients had an improvement in their pain scores. 64 (77%) patients had evidence of intraosseous and/or extraosseous bone formation on their follow-up scan. Conclusion. Non-operative management in the form of bracing and systemic therapy is a safe and effective treatment for spinal instability and spinal cord compression in myeloma. Treatment of unstable myelomatous lesions of the spine with or without cord compression should not follow traditional guidelines for MSCC. The decision to adopt a non-operative approach in this cohort of patients should ideally be made in a tertiary centre with expertise in multiple myeloma and in a multidisciplinary setting


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_9 | Pages 24 - 24
1 Sep 2019
Freidin M Kraatari M Skarp S Määttä J Kettunen J Niinimäki J Karppinen J Männikkö M Williams F
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Objective. Modic changes (MC), a form of intervertebral disc degeneration visible as subchondral and vertebral bone marrow changes on spine magnetic resonance (MR), are known to be associated with low back pain. This study aimed to identify genes contributing to the development of MC using genome-wide association study. Methods. Presence of MC was evaluated in lumbar MR images in the Northern Finland Birth Cohort 1966 (NFBC1966, N=1182) and TwinsUK (N=647). Genome-wide association analyses were carried out in the cohorts separately using a linear regression model fitted to test for additive effects of SNPs and adjusting for age, sex, BMI, and either family relatedness via a kinship matrix (TwinsUK) or population stratification using principal components (NFBC1966). Meta-analysis of the two studies was carried out using the inverse-variance weighting approach. Results. A locus associated with MC reaching genome-wide significance (p<5e-8) was found on chromosome 9 with the lead SNP rs1934268 in intron 6 of the PTPRD gene. The SNP is located in the region of binding for a number of transcription factors which are involved in the development of the musculoskeletal system and spine cord. Conclusions. The first GWAS of MC has identified a likely functional intronic locus in PTPRD on chromosome 9 implicating musculoskeletal development. This work sheds light on the genesis of MC and paves the way for further studies on the shared genetic factors underlying the various features of spine degeneration. No conflicts of interest. Sources of Funding: The study was supported by EU FP7 project PainOMICs (grant agreement #602736), University of Oulu (grant #24000692), Oulu University Hospital (grant #24301140), and the European Regional Development Fund (grant # 539/2010 A31592). MBF, MK, and SS contributed equally to this study


The Bone & Joint Journal
Vol. 98-B, Issue 3 | Pages 395 - 401
1 Mar 2016
Helenius I Keskinen H Syvänen J Lukkarinen H Mattila M Välipakka J Pajulo O

Aims. In a multicentre, randomised study of adolescents undergoing posterior spinal fusion for idiopathic scoliosis, we investigated the effect of adding gelatine matrix with human thrombin to the standard surgical methods of controlling blood loss. Patients and Methods. Patients in the intervention group (n = 30) were randomised to receive a minimum of two and a maximum of four units of gelatine matrix with thrombin in addition to conventional surgical methods of achieving haemostasis. Only conventional surgical methods were used in the control group (n = 30). We measured the intra-operative and total blood loss (intra-operative blood loss plus post-operative drain output). Results. Each additional hour of operating time increased the intra-operative blood loss by 356.9 ml (p < 0.001) and the total blood loss by 430.5 ml (p < 0.001). Multiple linear regression analysis showed that the intervention significantly decreased the intra-operative (-171 ml, p = 0.025) and total blood loss (-177 ml, p = 0.027). The decrease in haemoglobin concentration from the day before the operation to the second post-operative day was significantly smaller in the intervention group (-6 g/l, p = 0.013) than in the control group. . Conclusion. The addition of gelatine matrix with human thrombin to conventional methods of achieving haemostasis reduces both the intra-operative blood loss and the decrease in haemoglobin concentration post-operatively in adolescents undergoing posterior spinal fusion for idiopathic scoliosis. Take home message: A randomised clinical trial showed that gelatine matrix with human thrombin decreases intra-operative blood loss by 30% when added to traditional surgical haemostatic methods in adolescents undergoing posterior spinal fusion for idiopathic scoliosis. Cite this article: Bone Joint J 2016;98-B:395–401


Bone & Joint Open
Vol. 4, Issue 11 | Pages 873 - 880
17 Nov 2023
Swaby L Perry DC Walker K Hind D Mills A Jayasuriya R Totton N Desoysa L Chatters R Young B Sherratt F Latimer N Keetharuth A Kenison L Walters S Gardner A Ahuja S Campbell L Greenwood S Cole A

Aims

Scoliosis is a lateral curvature of the spine with associated rotation, often causing distress due to appearance. For some curves, there is good evidence to support the use of a spinal brace, worn for 20 to 24 hours a day to minimize the curve, making it as straight as possible during growth, preventing progression. Compliance can be poor due to appearance and comfort. A night-time brace, worn for eight to 12 hours, can achieve higher levels of curve correction while patients are supine, and could be preferable for patients, but evidence of efficacy is limited. This is the protocol for a randomized controlled trial of ‘full-time bracing’ versus ‘night-time bracing’ in adolescent idiopathic scoliosis (AIS).

Methods

UK paediatric spine clinics will recruit 780 participants aged ten to 15 years-old with AIS, Risser stage 0, 1, or 2, and curve size (Cobb angle) 20° to 40° with apex at or below T7. Patients are randomly allocated 1:1, to either full-time or night-time bracing. A qualitative sub-study will explore communication and experiences of families in terms of bracing and research. Patient and Public Involvement & Engagement informed study design and will assist with aspects of trial delivery and dissemination.


Bone & Joint Research
Vol. 12, Issue 4 | Pages 245 - 255
3 Apr 2023
Ryu S So J Ha Y Kuh S Chin D Kim K Cho Y Kim K

Aims

To determine the major risk factors for unplanned reoperations (UROs) following corrective surgery for adult spinal deformity (ASD) and their interactions, using machine learning-based prediction algorithms and game theory.

Methods

Patients who underwent surgery for ASD, with a minimum of two-year follow-up, were retrospectively reviewed. In total, 210 patients were included and randomly allocated into training (70% of the sample size) and test (the remaining 30%) sets to develop the machine learning algorithm. Risk factors were included in the analysis, along with clinical characteristics and parameters acquired through diagnostic radiology.


Bone & Joint Research
Vol. 10, Issue 12 | Pages 797 - 806
8 Dec 2021
Chevalier Y Matsuura M Krüger S Traxler H Fleege† C Rauschmann M Schilling C

Aims

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.

Methods

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.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVII | Pages 1 - 1
1 Jun 2012
Schwend R Akbarnia B Blakemore L Schmidt J Strauss K
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Introduction. The Hamann-Todd collection at the Cleveland Museum of Natural History (Cleveland, OH, USA) includes 63 paediatric skeletal specimens in varying condition and completeness. The initial data collection included representative skeletons of children aged 1–18 years. The aim of this study was to better understand the growth patterns of the paediatricspine and ribs. Methods. Data from vertebrae and corresponding ribs were collected. Data included 46 measurements from the vertebral body and ribs at T1, T4, T7, T10, and L3. Measurements were obtained with Vernier calipers, tape measures, and photographs of each bone. Several specimens were digitised with a Next Engine 3D laser scanner. The initial analysis used caliper-derived data, with some measurements obtained from photographs. The data were analysed by age, specific bone, and morphological features. More than 2000 cross correlations were studied. Linear regressions were done on scalar measurements with SAS (version 9.1.3) and JMP (version 8.0). Although the general demographics for each child were known, specifics such as height and weight or previous trauma were not. Results. Data analysis showed linear relationships in the ribs and growing spine. For example, the figure shows the data and linear regression for the right rib at T7 for each age. Rib width showed no significant increase with age (r2=0·001), whereas rib height had a linear increase (r2=0·754). Other measurements, such as costal length, were highly correlated with age. Conclusions. Direct measurements of paediatric cadaveric bones can be statistically analysed to provide insight into normal human growth. The data show a linear growth of the spine and rib cage from ages 1–18 years. Relatively little is known about the normal growth of human ribs and spine. This is the first known osteological data collection of the growing ribs and spine in non-scoliotic children. Understanding of chest growth will help to improve treatment of spine and chest-wall deformity in growing children


The Bone & Joint Journal
Vol. 104-B, Issue 1 | Pages 112 - 119
1 Jan 2022
Pietton R Bouloussa H Langlais T Taytard J Beydon N Skalli W Vergari C Vialle R

Aims

This study addressed two questions: first, does surgical correction of an idiopathic scoliosis increase the volume of the rib cage, and second, is it possible to evaluate the change in lung function after corrective surgery for adolescent idiopathic scoliosis (AIS) using biplanar radiographs of the ribcage with 3D reconstruction?

Methods

A total of 45 patients with a thoracic AIS which needed surgical correction and fusion were included in a prospective study. All patients underwent pulmonary function testing (PFT) and low-dose biplanar radiographs both preoperatively and one year after surgery. The following measurements were recorded: forced vital capacity (FVC), slow vital capacity (SVC), and total lung capacity (TLC). Rib cage volume (RCV), maximum rib hump, main thoracic curve Cobb angle (MCCA), medial-lateral and anteroposterior diameter, and T4-T12 kyphosis were calculated from 3D reconstructions of the biplanar radiographs.


The Journal of Bone & Joint Surgery British Volume
Vol. 94-B, Issue 1 | Pages 93 - 97
1 Jan 2012
Lee JH Lee J Park JW Shin YH

In patients with osteoporosis there is always a strong possibility that pedicle screws will loosen. This makes it difficult to select the appropriate osteoporotic patient for a spinal fusion. The purpose of this study was to determine the correlation between bone mineral density (BMD) and the magnitude of torque required to insert a pedicle screw. To accomplish this, 181 patients with degenerative disease of the lumbar spine were studied prospectively. Each underwent dual-energy x-ray absorptiometry (DEXA) and intra-operative measurement of the torque required to insert each pedicle screw. The levels of torque generated in patients with osteoporosis and osteopenia were significantly lower than those achieved in normal patients. Positive correlations were observed between BMD and T-value at the instrumented lumbar vertebrae, mean BMD and mean T-value of the lumbar vertebrae, and mean BMD and mean T-value of the proximal femur. The predictive torque (Nm) generated during pedicle screw insertion was [-0.127 + 1.62 × (BMD at the corresponding lumbar vertebrae)], as measured by linear regression analysis. The positive correlation between BMD and the maximum torque required to insert a pedicle screw suggests that pre-operative assessment of BMD may be useful in determining the ultimate strength of fixation of a device, as well as the number of levels that need to be fixed with pedicle screws in patients who are suspected of having osteoporosis


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_6 | Pages 3 - 3
1 Feb 2016
Holt N Pincus T
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Background:. A distinction has been posited between cognitive (informational) and affective (emotional) reassurance, with a suggestion that affective reassurance may negatively affect patient outcomes by reducing patients' motivation to engage with information conducive to recovery. Cognitive reassurance, though, provides explanations and information to help patients self-manage, and so aids recovery. However, research is lacking on how each actually affects patient outcomes in primary care. Purpose of the Study:. To develop a valid measure of practitioner reassurance, and assess the impact of different reassurance strategies on patients' outcomes. Methods:. A 30-item questionnaire was developed and piloted. This questionnaire was sent to patients who had recently consulted their GP for low back pain, along with measures of satisfaction and enablement. After 3 months, participants returned questionnaires assessing psychological and pain-related outcomes. The questionnaire was validated using Rasch modelling, and the effects of reassurance on outcomes were assessed using hierarchical linear regressions. Results:. The questionnaire was reduced to 12-items, consisting of 4 3-item subscales which were shown to be valid and reliable. Practitioners' cognitive reassurance was associated with lower pain intensity 3-months post-consultation, whereas affective reassurance showed the opposite effect. Use of affective reassurance alone of the 4 reassurance subscales failed to predict patient satisfaction. Affective reassurance showed positive association with enablement, but negatively predicted further healthcare utilisation at 3-months. Conclusion:. There is some evidence that cognitive reassurance is more beneficial to patients than affective reassurance, which can lead to worse pain and increased healthcare utilisation


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_6 | Pages 5 - 5
1 Feb 2016
Beneciuk J Hill J Campbell P George S Afolabi E Dunn K Foster N
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Purpose and Background:. To identify treatment effect modifiers within the STarT Back Trial which demonstrated prognostic stratified care was effective in comparison to standard care for patients with low back pain. Methods:. Secondary analysis of the STarT Back Trial using 688 patients with available 4-month follow-up data. Disability (baseline and 4 months) was assessed using the Roland Morris Disability Questionnaire (RMDQ) using continuous and dichotomized (>7) outcome scores. Potential treatment effect modifiers were evaluated with group x predictor interaction terms using linear and logistic regression models. Modifiers included: age, gender, education, socio-economic status (SES), employment status, work satisfaction, episode duration, general health (SF-12), number of pain medications, and treatment expectations. Results:. No significant treatment effect modifiers were identified using linear regression, however logistic regression analysis identified SES as a treatment modifier (interaction: OR = 0.65; 95% confidence interval = 0.42 to 0.98). Comparing those receiving stratified care versus best current care, the proportion of patients with poor 4 month outcome was similar for lower SES patients (35.4% vs. 37.2%), yet different for high SES patients (19.3% vs. 38.9%). No other treatment effect modifiers were identified; however exploratory analyses indicated trends for worse outcomes with increased age, patients taking ≥3 medications, those with lower education, and those with poor treatment expectations as potential treatment effect modifiers. Conclusion:. SES was identified as a treatment effect modifier in the STarT Back Trial with patients with lower SES not benefiting from stratified care. The explanations for this finding need further exploration


The Bone & Joint Journal
Vol. 103-B, Issue 1 | Pages 148 - 156
1 Jan 2021
Tsirikos AI Carter TH

Aims

To report the surgical outcome of patients with severe Scheuermann’s kyphosis treated using a consistent technique and perioperative management.

Methods

We reviewed 88 consecutive patients with a severe Scheuermann's kyphosis who had undergone posterior spinal fusion with closing wedge osteotomies and hybrid instrumentation. There were 55 males and 33 females with a mean age of 15.9 years (12.0 to 24.7) at the time of surgery. We recorded their demographics, spinopelvic parameters, surgical correction, and perioperative data, and assessed the impact of surgical complications on outcome using the Scoliosis Research Society (SRS)-22 questionnaire.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_4 | Pages 1 - 1
1 Feb 2014
Zehra U Robson-Brown K Adams M Dolan P
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Introduction. Decreasing endplate porosity has been proposed as a risk factor for intervertebral disc degeneration, because it interferes with disc metabolite transport. However, endplate porosity has recently been shown to increase with age and disc degeneration. We hypothesise that this increase reflects adaptive remodelling in response to altered loading from adjacent discs. Methods. Nineteen cadaver motion segments (61–98 yrs) were compressed to 1kN while a pressure-transducer was pulled across the mid-sagittal diameter of the disc. Stress profiles indicated nucleus (intradiscal) pressure (IDP) and maximum stress in the anterior and posterior annulus. Subsequently, micro-CT was used to evaluate endplate porosity along the antero-posterior diameter of the adjacent endplates. Data were analysed using ANOVA and linear regression. Results. Endplate porosity averaged 67% centrally (where IDP averaged 0.85MPa) and decreased steadily to 48% and 53% in the anterior and posterior periphery, where maximum stresses were 1.37MPa and 1.33MPa, respectively. In each region, porosity was inversely related to IDP (or maximum stress) with R. 2. = 0.49, 0.32 and 0.31 respectively (P<0.001 in each case). Porosity was 3% higher in the inferior (weaker) endplate of the disc compared to the superior endplate (P=0.07). Conclusion. In old spines, strong correlations between endplate porosity and stress in each anatomical region indicate mechanically-adaptive remodelling. Regional differences in endplate porosity (across the antero-posterior diameter) probably reflect the varying nutritional demands of nucleus and annulus, as well as adaptations to loading from an adjacent decompressed disc. In younger age-groups, high loading could possibly reduce endplate porosity, promoting disc degeneration


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_4 | Pages 30 - 30
1 Feb 2014
Morris T Hee SW Stallard N Underwood M Patel S
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Background. We have developed a LBP (low back pain) repository with IPD (individual patient data) from therapist-delivered intervention RCT's from various institutions, nationally and internationally (19 trials, 9328 patients). We will perform IPD meta-analyses to identify and determine the most effective and cost-effective treatments for subgroups of patients. Disability due to LBP is a key outcome of interest. However, there was no common disability measurement that was used in all the RCT's. We report here our assessment as to whether different disability measures are sufficiently comparable to allow pooling across trials. Method. We used data from seven trials (n = 5015 patients) that had at least two of the following measurements: RMDQ (Roland Morris Disability Questionnaire), MVK (Modified Von Korff disability score), physical component scale of SF-12/36, Patient Specific Functional Scale, and Hannover Functional Ability Questionnaire. Within each trial, the change score between baseline and short-term follow-up was computed. These change scores were then converted from one outcome measure to another with linear regression and ridge-reroughed linear models. They were also tested for correlation and responsiveness (the ability to detect changes in condition, measured by standardised response means). Conclusion. Most of the correlations between outcome measurements were high (>0.5), but responsiveness was often significantly different. Moreover, the accuracy of the conversions was poor, e.g. >40% of predictions from the conversion of RMDQ to MVK were incorrect by more than 10 points. The lack of agreement between different outcome measures suggests that conversion between different disability measurements is not recommended


The Bone & Joint Journal
Vol. 103-B, Issue 4 | Pages 734 - 738
1 Apr 2021
Varshneya K Jokhai R Medress ZA Stienen MN Ho A Fatemi P Ratliff JK Veeravagu A

Aims

The aim of this study was to identify the risk factors for adverse events following the surgical correction of cervical spinal deformities in adults.

Methods

We identified adult patients who underwent corrective cervical spinal surgery between 1 January 2007 and 31 December 2015 from the MarketScan database. The baseline comorbidities and characteristics of the operation were recorded. Adverse events were defined as the development of a complication, an unanticipated deleterious postoperative event, or further surgery. Patients aged < 18 years and those with a previous history of tumour or trauma were excluded from the study.


The Bone & Joint Journal
Vol. 102-B, Issue 10 | Pages 1375 - 1383
3 Oct 2020
Zhang T Sze KY Peng ZW Cheung KMC Lui YF Wong YW Kwan KYH Cheung JPY

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.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_4 | Pages 2 - 2
1 Feb 2014
Matthews S Horner M Zehra U Robson-Brown K Dolan P
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Introduction. Dual energy X-ray absorptiometry (DEXA) is the gold standard for assessing bone mineral density (BMD) and fracture risk in vivo. However, it has limitations in the spine because vertebrae show marked regional variations in BMD that are difficult to detect clinically. This study investigated whether micro-CT can provide improved estimates of BMD that better predict vertebral strength. Methods. Ten cadaveric vertebral bodies (mean age: 83.7 +/− 10.8 yrs) were scanned using lateral-projection DEXA and Micro-CT. Standardised protocols were used to determine BMD of the whole vertebral body and of anterior/posterior and superior/inferior regions. Vertebral body volume was assessed by water displacement after which specimens were compressed to failure to determine their compressive strength. Specimens were then ashed to determine their bone mineral content (BMC). Parameters were compared using ANOVA and linear regression. Results. Measures of volumetric BMD obtained from Micro-CT were significantly higher than those obtained by DEXA (P<0.001), and estimates using the two techniques were not significantly correlated. DEXA measurements were strongly predictive of compressive strength, with areal BMD of the anterior vertebral body being the best predictor (R. 2. = 0.722, P = 0.002). Micro-CT measurements did not predict strength. Vertebral body BMD (derived from ash weight) correlated more highly with volumetric BMD values obtained from DEXA (R = 0.88) than those obtained from micro-CT (R = 0.72). Conclusion. BMD assessed by lateral DEXA predicted strength and BMC of osteoporotic vertebrae more accurately than micro-CT measures. Poor correlation between BMD measurements from DEXA and micro-CT suggests that ‘phantoms’ used in Micro-CT may require fine-tuning in order to better represent osteoporotic vertebrae


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVI | Pages 28 - 28
1 Jun 2012
Budd H Wordsworth D Sharp D
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Lumbar spine foraminal stenosis has previously been defined by the foraminal and posterior disc height. We performed a study to determine whether residual clinically significant foraminal stenosis correlates with foraminal dimensions and peri-neural fat signal loss in a group of patients with leg pain undergoing surgery for lateral recess stenosis. We retrospectively studied the pre-operative para-sagittal MRI slices of 57 patients undergoing lumbar decompression and measured pre- and post-operative VAS as a primary outcome measure to evaluate surgical success. We performed a linear regression analysis comparing change in VAS score, 1 year VAS and percentage change in VAS with foraminal height and width and found no significant correlation (R. 2. <0.2 for all correlations). We identified a sub-group of 16 patients with absent perineural foraminal fat signal with a significantly increased probability of post-operative VAS>2 compared to patients with present fat signal (p=0.0001) who all had foraminal height <10mm. In conclusion, we were unable to define dimensional foraminal parameters for clinically significant foraminal stenosis on para-sagittal MRI. Obliteration of perineural fat was associated with worse outcome and post-operative leg pain. The aetiology of foraminal stenosis is multi-factorial and more detailed imaging of the foramen is required. We recommend that coronal and fine para-sagittal MRI slices are analysed to evaluate patients with central and lateral recess stenosis for co-existing foraminal stenosis