Aims. The aims of this study were to determine the diagnostic yield of image-guided biopsy in providing a final diagnosis in patients with suspected infectious spondylodiscitis, to report the diagnostic accuracy of various microbiological tests and histological examinations in these patients, and to report the epidemiology of infectious spondylodiscitis from a country where tuberculosis (TB) is endemic, including the incidence of drug-resistant TB. Methods. A total of 284 patients with clinically and radiologically suspected infectious spondylodiscitis were prospectively recruited into the study. Image-guided biopsy of the vertebral lesion was performed and specimens were sent for various microbiological tests and histological examinations. The final diagnosis was determined using a composite reference standard based on clinical, radiological, serological, microbiological, and histological findings. The overall diagnostic yield of the biopsy, and that for each test, was calculated in light of the final diagnosis. Results. The final diagnosis was tuberculous spondylodiscitis in 250 patients (88%) and pyogenic spondylodiscitis in 22 (7.8%). Six (2.1%) had a noninfectious condition-mimicking infectious spondylodiscitis, and six (2.1%) had no definite diagnosis and improved without specific treatment. The diagnosis was made by image-guided biopsy in 152 patients (56%) with infectious spondylodiscitis. Biopsy was contributory in identifying 132/250 patients (53%) with tuberculous spondylodiscitis, and 20/22 patients (91%) with pyogenic spondylodiscitis. Histological examination was the most sensitive diagnostic modality, followed by Xpert MTB/RIF assay. Conclusion. Image-guided biopsy has a reasonably high diagnostic yield in patients with suspected infectious spondylodiscitis. A combination of histological examination, Xpert MTB/RIF assay, bacterial culture, and sensitivity provides high diagnostic accuracy in a country in which TB is endemic. Cite this article: Bone Joint J 2022;104-B(1):120–126

Aims. Implant-related postoperative spondylodiscitis (IPOS) is a severe complication in spine surgery and is associated with high morbidity and mortality. With growing knowledge in the field of periprosthetic joint infection (PJI), equivalent investigations towards the management of implant-related infections of the spine are indispensable. To our knowledge, this study provides the largest description of cases of IPOS to date. Methods. Patients treated for IPOS from January 2006 to December 2020 were included. Patient demographics, parameters upon admission and discharge, radiological imaging, and microbiological results were retrieved from medical records. CT and MRI were analyzed for epidural, paravertebral, and intervertebral abscess formation, vertebral destruction, and endplate involvement. Pathogens were identified by CT-guided or intraoperative biopsy, intraoperative tissue sampling, or implant sonication. Results. A total of 32 cases of IPOS with a mean patient age of 68.7 years (37.6 to 84.1) were included. Diabetes, age > 60 years, and history of infection were identified as risk factors. Patient presentation upon admission included a mean body temperature of 36.7°C (36.1 to 38.0), back pain at rest (mean visual analogue scale (VAS) mean 5/10) and when mobile (mean VAS 6/10), as well as elevated levels of CRP (mean 76.8 mg/l (0.4 to 202.9)) and white blood cell count (mean 9.2 units/nl (2.6 to 32.8)). Pathogens were identified by CT-guided or conventional biopsy, intraoperative tissue sampling, or sonication, and Gram-positive cocci presented as the most common among them. Antibiotic therapy was established in all cases with pathogen-specific treatment in 23 (71.9%) subjects. Overall 27 (84.4%) patients received treatment by debridement, decompression, and fusion of the affected segment. Conclusion. Cases of IPOS are rare and share similarities with spontaneous spondylodiscitis. While procedures such as CT-guided biopsy and sonication are valuable tools in the diagnosis of IPOS, MRI and intraoperative tissue sampling remain the gold standard. Research on known principles of PJI such as implant retention versus implant exchange need to be expanded to the field of spine surgery. Cite this article: Bone Jt Open 2023;4(11):832–838

Aims. Gram-negative infections are associated with comorbid patients, but outcomes are less well understood. This study reviewed diagnosis, management, and treatment for a cohort treated in a tertiary spinal centre. Methods. A retrospective review was performed of all gram-negative spinal infections (n = 32; median age 71 years; interquartile range 60 to 78), excluding surgical site infections, at a single centre between 2015 to 2020 with two- to six-year follow-up. Information regarding organism identification, antibiotic regime, and treatment outcomes (including clinical, radiological, and biochemical) were collected from clinical notes. Results. All patients had comorbidities and/or non-spinal procedures within the previous year. Most infections affected lumbar segments (20/32), with Escherichia coli the commonest organism (17/32). Causative organisms were identified by blood culture (23/32), biopsy/aspiration (7/32), or intraoperative samples (2/32). There were 56 different antibiotic regimes, with oral (PO) ciprofloxacin being the most prevalent (13/56; 17.6%). Multilevel, contiguous infections were common (8/32; 25%), usually resulting in bone destruction and collapse. Epidural collections were seen in 13/32 (40.6%). In total, five patients required surgery, three for neurological deterioration. Overall, 24 patients improved or recovered with a mean halving of CRP at 8.5 days (SD 6). At the time of review (two to six years post-diagnosis), 16 patients (50%) were deceased. Conclusion. This is the largest published cohort of gram-negative spinal infections. In older patients with comorbidities and/or previous interventions in the last year, a high level of suspicion must be given to gram-negative infection with blood cultures and biopsy essential. Early organism identification permits targeted treatment and good initial clinical outcomes; however, mortality is 50% in this cohort at a mean of 4.2 years (2 to 6) after diagnosis. Cite this article: Bone Jt Open 2024;5(5):435–443

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. Spinal tuberculosis (TB) remains an important concern. Although spinal TB often has sequelae such as myelopathy after treatment, the predictive factors affecting such unfavourable outcomes are not yet established. We investigated the clinical manifestations and predictors of unfavourable treatment outcomes in patients with spinal TB. Patients and Methods. We performed a multicentre retrospective cohort study of patients with spinal TB. Unfavourable outcome was defined according to previous studies. The prognostic factors for unfavourable outcomes as the primary outcome were determined using multivariable logistic regression analysis and a linear mixed model was used to compare time course of inflammatory markers during treatment. A total of 185 patients were included, of whom 59 patients had unfavourable outcomes. Results. In multivariate regression analysis, the factors associated with unfavourable outcome were old age (odds ratio (OR) 2.51; 95% confidence interval (CI) 1.07 to 5.86; p = 0.034), acid-fast bacilli (AFB) smear positivity in specimens obtained through biopsy (OR 3.05; 95% CI 1.06 to 8.80; p = 0.039), and elevated erythrocyte sedimentation rate (ESR) at the end of treatment (OR 3.85; 95% CI 1.62 to 9.13; p = 0.002). Patients with unfavourable outcomes had a significant trend toward higher ESR during treatment compared with patients with favourable outcome (p = 0.009). Duration of anti-TB and surgical treatment did not affect prognosis. Conclusion. Elevated ESR at the end of treatment could be used as a marker to identify spinal TB patients with a poor prognosis. Patients whose ESR is not normalized during treatment, as well as those with old age and AFB smear positivity, should be aware of unfavourable outcomes. Cite this article: Bone Joint J 2019;101-B:1542–1549

Aims. The aim of this study was to determine the diagnostic utility of histological analysis in spinal biopsies for spondylodiscitis (SD). Patients and Methods. Clinical features, radiology, results of microbiology, histology, and laboratory investigations in 50 suspected SD patients were evaluated. In 29 patients, the final (i.e. treatment-based) diagnosis was pyogenic SD; in seven patients, the final diagnosis was mycobacterial SD. In pyogenic SD, the neutrophil polymorph (NP) infiltrate was scored semi-quantitatively by determining the mean number of NPs per (×400) high-power field (HPF). Results. Of the 29 pyogenic SD patients, 17 had positive microbiology and 21 positive histology (i.e. one or more NPs per HPF on average). All non-SD patients showed less than one NP per HPF. The presence of one or more NPs per HPF had a diagnostic sensitivity of 72.4%, specificity 100%, accuracy 100%, positive predictive value (PPV) 81.0%, and negative predictive value (NPV) 61.9%. Sensitivity, specificity, and accuracy were greater using the criterion of positive histology and/or microbiology than positive histology or microbiology alone. Granulomas were identified histologically in seven mycobacterial SD patients, and positive microbiology was detected in four. Conclusion. The diagnosis of pyogenic SD was more often confirmed by positive histology (one or more NPs per HPF on average) than by microbiology, although diagnostic sensitivity was greater when both histology and microbiology were positive. Cite this article: Bone Joint J 2019;101-B:246–252

Purpose. To elucidate the efficacy of carrying out additional vertebral biopsy procedure during percutaneous balloon kyphoplasty as a tool in determining malignant etiology. Methods and Results. We performed 138 percutaneous balloon kyphoplasty procedures in 85 patients during august 2007 to march 2010. Gender distribution was 25 males and 60 females. Age distribution was 33 to 85 years, with an average age of 67.4 years. The senior surgeon attempted vertebral biopsy during percutaneous balloon kyphoplasty procedure only when there was a clinical/operative suspicion of malignancy. We did not routinely biopsy all vertebrae, as this would mean additional procedure adding to the cost and operating time. In 42 procedures vertebral biopsy was attempted, of which 5 samples were reported as insufficient specimen. 37 biopsies (88%) were successfully analyzed. 3 biopsies (8.1%) were positive for malignancy. There were no complications encountered in the cases where additional biopsy procedure was carried out. Conclusion. There is not much literature supporting routine use and efficacy of biopsies during percutaneous balloon kyphoplasty procedures. Although the quality of bone could make vertebral biopsy challenging in all cases, we feel that improved technique of taking biopsies and maybe increasingly performing the additional biopsy procedure could detect more positive malignancies. Routine biopsies during percutaneous balloon kyphoplasty may be invaluable in diagnosing malignancies

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).

Introduction. Spinal infections constitute a spectrum of disease comprising pyogenic, tuberculous, nonpyogenic-nontuberculous and postoperative spinal infections. The aim of this study was to review the epidemiology, diagnostic yield of first and second biopsy procedures and microbiology trends from Sheffield Spinal Infection Database along with analysing prognostic predictors in spinal infections. Materials and Methods. Sheffield Spinal Infection Database collects data prospectively from regularly held Spinal infection MDTs. We accrued 125 spinal infections between September 2008 and October 2010. The medical records, blood results, radiology and bacteriology results of all patients identified were reviewed. In patients with negative first biopsy, second biopsy is contemplated and parenteral broad spectrum antibiotic treatment initiated. Results. There were 81 pyogenic, 16 tuberculous and 28 postoperative spinal infections. The mean age was 58.4 years (range, 19 to 88 years). There were 71 male and 54 female patients. There were 64 lumbar and 26 thoracic infections. Two level and multi-level spinal infections involving more than two segments occurred in 30 patients. Of sixty positive microbiology yields, the most common organism was methicillin sensitive staphylococcus aureus (n-23) followed by Streptococcal, E Coli and Coagulase negative staphylococcal and Pseudomonas infections. Second biopsy (done when first biopsy negative) was only positive in two patients. Conclusions. Annual incidence of de novo spinal infection was 48 (pyogenic-40, tuberculous-8). The most frequently isolated pathogen was Staphyloccus aureus. Multi-level infection, diabetic patients, resistant TB and postop infection in elderly patients constituted the ‘difficult to treat’ group in our experience. An algorithm for the diagnostic work-up and management of spinal infections is proposed

The Royal Liverpool and Broadgreen University Hospital, Liverpool, UK. Plasmacytoma is the localised form of multiple myeloma, which can affect any part of the body including the axial skeleton (Kelly et al, 2006; Ampil et al, 1995). These myelomas/plasmacytomas arise from one malignant clone of cells, which secrete the same type of immunoglobulin. Where the clone of cells remains localised, it is known as plasmacytoma, but when there is spread of the malignancy to multiple bones and marrow, it is known as multiple myeloma (Boccadoro and Pileri, 1995). We present a case of solitary sacral bone plasmacytoma (SBP), in a seventy year old man which presented as low back pain, following a fall. He was neurologically intact, and had no sphincteric incontinence, but MRI revealed a large expansile lesion in S1, which caused severe spinal stenosis, involving the left L5 exiting foramen, with an irregular area of low signal posteriorly. Bone scan showed increased tracer uptake in L5 and a mixed hot/photopaenic appearance in the mid-sacral region indicating tumor involvement. Myeloma screen confirmed that the serum IgA was high, with positive kappa monoclonal band, positive Bence Jones Protein (BJP), normal IgM and IgG, and normal calcium profile. CT-guided biopsy revealed sheets of mature plasma cells, consistent with the diagnosis. Fine needle aspiration biopsy of an enlarged groin lymph node revealed neoplastic infiltration, consistent with myeloma. Skeletal survey and CT chest/abdomen/pelvis (CAP) were not contributory. The patient had six courses of radiotherapy and improved remarkably, and is being considered for chemotherapy as well as follow up in the out-patients' department

Purpose of study. The aim of this study was to identify the incidence of Gram negative bacterial vertebral osteomyelitis (VO) within our unit during a 3-year study period and evaluate if this corresponds to published evidence that the occurrence is increasing. Methods. Between May 2007 and May 2010, all patients, over the age of 18 years, suffering from Gram-negative VO were identified and their microbiological diagnoses were evaluated. All patients were treated within a large tertiary spinal surgery unit in Leeds. Results. This study identified 79 patients with haematogenous VO. Of these 79 patients, 10 patients (12.66%) had Gram-negative organisms isolated. These organisms included E. Coli (4), Pseudomonal aeruginosa (3), Klebsiella pneumonia (1), Haemophilus influenza (1) and Enterobacter cloacae (1). Four patients had the causative organism isolated on =2 positive blood cultures, three from biopsy and =2 positive blood culture, one from biopsy alone and two were diagnosed from 1 positive blood culture. Conclusion. VO is a common manifestation of osteomyelitis in adults, representing 2-7% of all cases of osteomyelitis. Staphylococcus aureus is the most common causative aetiological agent in haematogenous spinal infections, accounting for between 40 - 60% of cases. Despite the fact that Gram negative bacteria infections represent a minor proportion of all cases of VO, around 15 - 23%, recent evidence suggests that the microbiology of this disease may be changing and the incidence of Gram-negative bacterial infections are increasing. This has been attributed a variety of factors including, an increasing proportion of individuals with predisposing risk factors such as advanced age, diabetes mellitus, malignancy and better diagnostic techniques. Results from our study show an incidence of Gram-negative VO of 12%, which is less than results quoted in the literature and does not confirm recent evidence that these types of spinal infections are increasing in incidence

Aims

With recent progress in cancer treatment, the number of advanced-age patients with spinal metastases has been increasing. It is important to clarify the influence of advanced age on outcomes following surgery for spinal metastases, especially with a focus on subjective health state values.

To report on the management of a patient with grade 1 holocord pilocytic astrocytoma and scoliosis. Case report of a rare spinal cord tumour and a management of the scoliosis. An 11 year boy complained of gradually worsening neck, back pain and pain in all limbs. This was accompanied by unsteadiness, weakness of lower limbs and bed wetting of recent onset. There was a family history of spinal cord tumour. Examination revealed signs of spinal cord compression and a left thoracic scoliosis. Magnetic resonance imaging showed an intra-medullary tumour extending through the spinal cord and syrinx formation. He underwent T1-3 approach for drainage of syrinx, biopsy of tumour and laminoplasty with plates. He was started on chemotherapy for 14 months. During this period a syringo-peritoneal shunt was inserted. There was further growth of the tumour and neurological deterioration. He subsequently underwent T8-L1 laminoplasty, debulking of tumour and insertion of dual diameter growing rods. There has been no significant neurological deterioration. There was good correction of the scoliosis with Cobb angle reducing from 50 to 15 degrees. Lengthening of growing rods has been done 4 times with good length achieved. Excision of tumour and growing rod insertion (not previously reported) is a good way of controlling neurological symptoms and the scoliosis in this rare spinal cord tumour

Introduction. Aneurysmal bone cysts are uncommon benign lesions affecting the spinal column. They mostly occur in the lumbar spine and have a propensity to affect adjacent vertebrae. We describe 14 aneurysmal bone cysts affecting the spinal column from the Scottish Bone Tumour Registry with regard to assess the incidence, demography, biological behaviour and recurrence rate. Materials and Methods. We identified 14 patients with aneurysmal bone cysts affecting the spinal column. Case notes and radiographs were retrospectively reviewed from the Scottish Bone Tumour registry. Results. There were 9 female and 5 male patients. The mean age at presentation was 24.5 years (range, 6 to 62 years). The spinal location consisted of cervical (3), thoracic (4), lumbar (6) and sacral (1). The treatment included curettage without bone grafting (3), excision (7) and surgical removal with biopsy in rest. Selective angiographic embolisation was carried out in one patient with a cervical cyst and percutaneous sclerotherapy was carried out on another with a sacral cyst. There were two recurrences, of which one was treated with radiotherapy and other with repeat curettage with successful final outcome. Conclusions. The incidence of aneurysmal bone cysts was 5.5% in our registry of all the spine tumours. The recurrence occurred in 14% (2 of 14). In addition to surgery, one should be aware of the role of angiographic embolisation and radiotherapy in selected primary and recurrent ABCs

Spinal disc infection is associated with a significant morbidity and mortality in the acute setting. On long term review it leads to significant moribidity due to the deformity and secondary osteoarthritic changes in the surrounding vertebral segments. Prospective collection of data of 21 patients suffering from discitis was collected over the span of last 10 years. The age group ranged between 21 -67 yrs. The male: female ratio was 1.2:1. The minimum delay in presentation since the onset of symptoms was 8 weeks. The detection of the micro-organism was either by needle/open biopsy or indirectly via blood cultures. Serial records were maintained of inflammatory markers. All patients received plain radiographs, gadolinium-enhanced magnetic resonance imaging scans, and bone/gallium radionuclide studies. Operative decompression was performed in 7 patients. Infection elsewhere was the most common predisposing factor. Leukocyte counts were elevated in 54% of spondylodiscitis cases. The erythrocyte sedimentation rate and CRP were elevated in all cases of epidural abscess. The most common organism was Staph Aureus. Antibiotics were administered for duration of at least 6 weeks. On long term, all patients developed deformity at the level of the infection, with half of them being symptomatic. Spinal infections are extremely morbid conditions demanding prompt diagnosis and urgent treatment to prevent complications. Ethics approval: Audit Committee Interest statement: No conflict of interest

Sacro-coccygeal chordomas pose a difficult diagnostic and therapeutic problem due to late presentation, large size, soft-tisue extension, difficulties in obtaining adequate resection margins, higher local recurrence rate and uncertain effectiveness of adjuvant treatment. We present a series of 21 patients of sacral chordomas obtained from Scottish Bone Tumour Registry to analyse predictors of local control and survival. The clinical and morphologic features, type of treatment and follow-up of 21 consecutive patients with sacral chordoma were retrospectively reviewed and analysed. The data were obtained from Scottish Bone Tumour Registry. The average age at time of the biopsy was 59 years (range, 12 to 82 years): twelve patients were male and nine were female. Pain was the presenting symptom in all patients. Two had intralesional (both recurred), 9 marginal (4 recurred) and 3 wide resections (1 recurred). Fifteen of the twenty-one patients were treated with adjuvant radiation therapy. In seven patients, the chordoma was inoperable and all but one were treated with adjuvant radiotherapy. Local recurrence and metastases occurred in 7 (50%) and 5 (23.8%) patients. The 5-year and 10-year survival were 38% and 14.2%, respectively. Excision of the lesion combined with adjuvant radiation therapy provided satisfactory results. Local recurrence presents a major problem in the management of sacral chordomas (50%). Intralesional resection should be avoided as it is associated with 100% local recurrence in our series

Aim. To identify patterns in referral and the management pathway of patients with primary bone tumours of the spine referred to the Orthopaedic Spine Unit in order to recommend ways to improve the service. Methods and Results. A retrospective notes and imaging review to evaluate the referral pathway undertaken by patients ending up in the orthopaedic spine unit over a 5 year period according to the recommendations for primary bone tumours. Significant events leading to potential improvement in outcomes were assessed. Recommendations for improvements are suggested. None of the 38 patients evaluated were referred within two weeks of presentation, and only 6 were referred directly to the bone tumour service. Almost half (15/32) of the patients who had an indirect referral pathway had a prior intervention. Five of these had non-surgical, while 10 had surgical interventions outside the tumour centre before their referral. Of these, seven had malignant tumours. Conclusion. In order to optimise outcome, patients with potentially malignant primary tumours of the spine should be referred directly to tumour services. Prior procedures should be limited to biopsy procedures and discussed with the tumour service before this is undertaken having appropriate investigation and imaging available. Guidelines for this should be directed at streamlining the referral pathway and encouraging communication between stakeholders. Further research should assess the impact of patient-related delay in presentation contributes to overall delay in referral to tumour service; how early radiological assessment may augment timely referral; and how indirect referral and prior intervention affect patient outcomes

Introduction. Metastatic involvement of the lumbo-sacral junction/sacrum usually signifies advanced disease. The aim of this study was to report our results on the management of patients with metastases referred to this anatomical region over the last 5 years (July 2006- July 2010). Methods. Retrospective analysis from a comprehensive spinal oncology database. Results. During this period, a total of 14 patients (mean age 65.6 years (58-87), 8 female, 6 male) were referred to our unit. The majority had symptoms of pain and neurological deterioration (11) with onset of pain considerably longer than neurology symptoms (296 days (7-1825) versus 7 days (1-28); 3 were non-ambulatory at presentation. The primary tumours were Renal cell (4), Breast (2), Prostate (2), GI (2), unknown primary (2), lung (1) and neuroendocrine (1). Operative procedures performed were decompression with lumbo-pelvic stabilisation (5), decompression with(out) biopsy (7), posterior decompression/reconstruction with anterior excision/stabilisation (1) and laminectomy with sacroplasty (1). There were 8/14 (57%) complications including neurological deterioration (2), wound infection (2) and metalwork revision (1). Post-operatively, 7 patients received radiotherapy, 3 improved one Frankel grade and the others remained stable. All patients were ambulatory. The mean survival was 412 days (105-1005) and most patients returned either back to their own home (8) or a nursing home (4). Conclusion. The incidence of metastases in this region is relatively uncommon. Surgical intervention has a high complication rate (8/14, 57%) but can be important in restoring/preserving neurological function, assisting with ambulatory function and allowing patients to return to their previous accommodation

Aims

HIV predisposes patients to opportunistic infections. However, with the establishment of Highly Active Anti-Retroviral Therapy (HAART), patients’ CD4 counts are maintained, as is a near normal life expectancy. This study aimed to establish the impact of HIV on the bacteriology of spondylodiscitis in a region in which tuberculosis (TB) is endemic, and to identify factors that might distinguish between them.

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