Aims. The aim of this study was to determine the influence of pelvic parameters on the tendency of patients with adolescent idiopathic scoliosis (AIS) to develop flatback deformity (thoracic hypokyphosis and lumbar hypolordosis) and its effect on quality-of-life outcomes. Patients and Methods. This was a radiological study of 265 patients recruited for Boston bracing between December 2008 and December 2013. Posteroanterior and lateral radiographs were obtained before, immediately after, and two-years after completion of bracing. Measurements of coronal and sagittal Cobb angles, coronal balance, sagittal vertical axis, and pelvic parameters were made. The refined 22-item Scoliosis Research Society (SRS-22r) questionnaire was recorded. Association between independent factors and outcomes of postbracing ≥ 6° kyphotic changes in the thoracic spine and ≥ 6° lordotic changes in the lumbar spine were tested using likelihood ratio chi-squared test and univariable logistic regression. Multivariable logistic regression models were then generated for both outcomes with odds ratios (ORs), and with SRS-22r scores. Results. Reduced T5-12 kyphosis (mean -4.3° (. sd. 8.2); p < 0.001), maximum thoracic kyphosis (mean -4.3° (. sd. 9.3); p < 0.001), and lumbar lordosis (mean -5.6° (. sd. 12.0); p < 0.001) were observed after bracing treatment. Increasing prebrace maximum kyphosis (OR 1.133) and lumbar lordosis (OR 0.92) was associated with postbracing hypokyphotic change. Prebrace sagittal vertical axis (OR 0.975), prebrace sacral slope (OR 1.127), prebrace pelvic tilt (OR 0.940), and change in maximum thoracic kyphosis (OR 0.878) were predictors for lumbar hypolordotic changes. There were no relationships between coronal deformity, thoracic kyphosis, or lumbar lordosis with SRS-22r scores. Conclusion. Brace treatment leads to flatback deformity with thoracic hypokyphosis and lumbar hypolordosis. Changes in the thoracic spine are associated with similar changes in the lumbar spine. Increased sacral slope, reduced pelvic tilt, and pelvic incidence are associated with reduced lordosis in the lumbar spine after bracing. Nevertheless, these sagittal parameter changes do not appear to be associated with worse quality of life. Cite this article: Bone Joint J 2019;101-B:1370–1378

Aims. The aim of this study is to test the hypothesis that three grades of sagittal compensation for standing posture (normal, compensated, and decompensated) correlate with health-related quality of life measurements (HRQOL). Methods. A total of 50 healthy volunteers (normal), 100 patients with single-level lumbar degenerative spondylolisthesis (LDS), and 70 patients with adult to elderly spinal deformity (deformity) were enrolled. Following collection of demographic data and HRQOL measured by the Scoliosis Research Society-22r (SRS-22r), radiological measurement by the biplanar slot-scanning full body stereoradiography (EOS) system was performed simultaneously with force-plate measurements to obtain whole body sagittal alignment parameters. These parameters included the offset between the centre of the acoustic meatus and the gravity line (CAM-GL), saggital vertical axis (SVA), T1 pelvic angle (TPA), McGregor slope, C2-7 lordosis, thoracic kyphosis (TK), lumbar lordosis (LL), pelvic incidence (PI), PI-LL, sacral slope (SS), pelvic tilt (PT), and knee flexion. Whole spine MRI examination was also performed. Cluster analysis of the SRS-22r scores in the pooled data was performed to classify the subjects into three groups according to the HRQOL, and alignment parameters were then compared among the three cluster groups. Results. On the basis of cluster analysis of the SRS-22r subscores, the pooled subjects were divided into three HRQOL groups as follows: almost normal (mean 4.24 (SD 0.32)), mildly disabled (mean 3.32 (SD 0.24)), and severely disabled (mean 2.31 (SD 0.35)). Except for CAM-GL, all the alignment parameters differed significantly among the cluster groups. The threshold values of key alignment parameters for severe disability were TPA > 30°, C2-7 lordosis > 13°, PI-LL > 30°, PT > 28°, and knee flexion > 8°. Lumbar spinal stenosis was found to be associated with the symptom severity. Conclusion. This study provides evidence that the three grades of sagittal compensation in whole body alignment correlate with HRQOL scores. The compensation grades depend on the clinical diagnosis, whole body sagittal alignment, and lumbar spinal stenosis. The threshold values of key alignment parameters may be an indication for treatment. Cite this article: Bone Joint J 2020;102-B(10):1359–1367

The ratio of the sagittal diameter of the cervical canal to the corresponding diameter of the vertebral body has been described as a reliable means for assessing stenosis of the canal and detecting those at risk of cervical neuropraxia. The use of ratio techniques has the advantage of avoiding variation in magnification when direct measurements are made from plain radiographs. We examined the reliability of this method using plain lateral radiographs of unknown magnification and CT scans. We also assessed other possible ratios of anatomical measurements as a guide to the diameter of the canal. Our findings showed a poor correlation between the true diameter of the canal and the ratio of its sagittal diameter to that of the vertebral body. No other more reliable ratio was identified. The variability in anatomical morphology means that the use of ratios from anatomical measurements within the cervical spine is not reliable in determining the true diameter of the cervical canal

We investigated the relationship between spinopelvic parameters and disc degeneration in young adult patients with spondylolytic spondylolisthesis. A total of 229 men with a mean age of 21 years (18 to 26) with spondylolytic spondylolisthesis were identified. All radiological measurements, including pelvic incidence, sacral slope, pelvic tilt, lumbar lordosis, sacral inclination, lumbosacral angle (LSA), and sacrofemoral distance, were calculated from standing lateral lumbosacral radiographs. The degree of intervertebral disc degeneration was classified using a modified Pfirrmann scale. We analysed the spinopelvic parameters according to disc level, degree of slip and disc degeneration.

There were significant positive correlations between the degree of slip and pelvic incidence (p = 0.009), sacral slope (p = 0.003) and lumbar lordosis (p = 0.010). The degree of slip and the LSA were correlated with disc degeneration (p < 0.001 and p = 0.003, respectively). There was also a significant difference between the degree of slip (p < 0.001) and LSA (p = 0.006) according to the segmental level of disc degeneration.

Cite this article: Bone Joint J 2013;95-B:1239–43.

Aims. 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. Methods. Between July 2017 and July 2019, 40 patients with cervical OPLL were equally randomized to undergo surgery with an ACOE or a PTLF. The clinical and radiological results were compared between the two groups. Results. The Japanese Orthopaedic Association (JOA) score and recovery rate in the ACOE group were significantly higher than those in the PTLF group during two years postoperatively, provided that the canal occupying ratio (COR) was > 50%, or the K-line was negative. There was no significant difference in JOA scores and rate of recovery between the two groups in those in whom the COR was < 50%, or the K-line was positive. There was no significant difference in the Cobb angle between C2 and C7, sagittal vertical axis, cervical range of motion (ROM), and complications between the two groups. Conclusion. Compared with PTLF, ACOE is a preferred surgical approach for the surgical management of patients with cervical OPLL in that it offers a better therapeutic outcome when the COR is > 50%, or the K-line is negative, and it also preserves better cervical curvature and sagittal balance. The prognosis of ACOE is similar to that of PTLE when the COR is < 50%, or the K-line is positive. Cite this article: Bone Joint J 2023;105-B(4):412–421

Aims. The aim of this study was to investigate the impact of the level of upper instrumented vertebra (UIV) in frail patients undergoing surgery for adult spine deformity (ASD). Methods. Patients with adult spinal deformity who had undergone T9-to-pelvis fusion were stratified using the ASD-Modified Frailty Index into not frail, frail, and severely frail categories. ASD was defined as at least one of: scoliosis ≥ 20°, sagittal vertical axis (SVA) ≥ 5 cm, or pelvic tilt ≥ 25°. Means comparisons tests were used to assess differences between both groups. Logistic regression analyses were used to analyze associations between frailty categories, UIV, and outcomes. Results. A total of 477 patients were included (mean age 60.3 years (SD 14.9), mean BMI 27.5 kg/m. 2. (SD 5.8), mean Charlson Comorbidity Index (CCI) 1.67 (SD 1.66)). Overall, 74% of patients were female (n = 353), and 49.6% of patients were not frail (237), 35.4% frail (n = 169), and 15% severely frail (n = 71). At baseline, differences in age, BMI, CCI, and deformity were significant (all p = 0.001). Overall, 15.5% of patients (n = 74) had experienced mechanical complications by two years (8.1% not frail (n = 36), 15.1% frail (n = 26), and 16.3% severely frail (n = 12); p = 0.013). Reoperations also differed between groups (20.2% (n = 48) vs 23.3% (n = 39) vs 32.6% (n = 23); p = 0.011). Controlling for osteoporosis, baseline deformity, and degree of correction (by sagittal age-adjusted score (SAAS) matching), frail and severely frail patients were more likely to experience mechanical complications if they had heart failure (odds ratio (OR) 6.6 (95% CI 1.6 to 26.7); p = 0.008), depression (OR 5.1 (95% CI 1.1 to 25.7); p = 0.048), or cancer (OR 1.5 (95% CI 1.1 to 1.4); p = 0.004). Frail and severely frail patients experienced higher rates of mechanical complication than ‘not frail’ patients at two years (19% (n = 45) vs 11.9% (n = 29); p = 0.003). When controlling for baseline deformity and degree of correction in severely frail and frail patients, severely frail patients were less likely to experience clinically relevant proximal junctional kyphosis or failure or mechanical complications by two years, if they had a more proximal UIV. Conclusion. Frail patients are at risk of a poor outcome after surgery for adult spinal deformity due to their comorbidities. Although a definitively prescriptive upper instrumented vertebra remains elusive, these patients appear to be at greater risk for a poor outcome if the upper instrumented vertebra is sited more distally. Cite this article: Bone Joint J 2024;106-B(11):1342–1347

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. Results. The mean follow-up was 8.4 years (2 to 14.9). There were 85 patients (96.6%) with a thoracic deformity. Posterior spinal fusion with closing-wedge osteotomies and hybrid instrumentation was used in 86 patients; two patients underwent combined anterior and posterior spinal fusion. The mean kyphosis was corrected from 94.5° to 47.5° (p < 0.001). Coronal and sagittal balance returned to normal. The rate of complications was 12.5%: there were no neurological deficits, implant failure, or revision surgery. SRS-22 scores improved from a mean 3.6 (1.3 to 4.1) to 4.6 (4.2 to 5.0) at two years (p < 0.001) with a high rate of patient satisfaction. Non-smokers and patients with lower preoperative SRS-22 scores showed greater improvement in their quality of life. Sagittal pelvic balance did not change after correction of the kyphosis and correlated with lumbar lordosis but not with thoracic or thoracolumbar kyphosis. Conclusion. Posterior spinal fusion using hybrid instrumentation, closing-wedge osteotomies, and iliac bone grafting achieves satisfactory correction of a severe kyphosis resulting in improvements in physical and mental health and a high degree of patient-reported satisfaction. Cite this article: Bone Joint J 2021;103-B(1):148–156

Aims. The direct posterior approach with subperiosteal dissection of the paraspinal muscles from the vertebrae is considered to be the standard approach for the surgical treatment of adolescent idiopathic scoliosis (AIS). We investigated whether or not a minimally-invasive surgery (MIS) technique could offer improved results. Methods. Consecutive AIS patients treated with an MIS technique at two tertiary centres from June 2013 to March 2016 were retrospectively included. Preoperative patient deformity characteristics, perioperative parameters, power of deformity correction, and complications were studied. A total of 93 patients were included. The outcome of the first 25 patients and the latter 68 were compared as part of our safety analysis to examine the effect of the learning curve. Results. In the first 25 cases, with a mean follow-up of 5.6 years (standard deviation (SD) 0.4), the mean preoperative major Cobb angle was 57.6° (SD 9.8°) and significantly corrected to mean 15.4° (SD 5.6°, 73% curve correction). The mean preoperative T5-T12 was 26.2 (SD 12.8) and significantly increased to mean 32.9 (SD 8.3). Both frontal and sagittal plane correction was conserved two years after surgery. The rate of perioperative complications was 12% and three further complications occurred (three deep delayed infection). In the latter cases, 68 patients were included with a mean follow-up time of three years (SD 0.6). The mean preoperative major Cobb angle was 58.4° (SD 9.2°) and significantly corrected to mean 20.4° (SD 7.3°).The mean preoperative T5-T12 kyphosis was 26.6° (SD 12.8°) and was significantly increased to mean 31.4° (SD 8.3°). Both frontal and sagittal correction was conserved two years after surgery. The perioperative (30 day) complication rate was 1.4%. Two (2.9%) additional complications occurred in two patients. Conclusion. MIS for AIS is associated with a significant correction of spine deformity in the frontal and sagittal planes, together with low estimated blood loss and short length of stay. The perioperative complication rate seems to be lower compared with the standard open technique based on the literature data. The longer-term safety of MIS for AIS needs to be documented with a larger cohort and compared with the standard posterior approach. Cite this article: Bone Joint J 2020;102-B(4):506–512

Aims. It is uncertain whether instrumented spinal fixation in nonambulatory children with neuromuscular scoliosis should finish at L5 or be extended to the pelvis. Pelvic fixation has been shown to be associated with up to 30% complication rates, but is regarded by some as the standard for correction of deformity in these conditions. The incidence of failure when comparing the most caudal level of instrumentation, either L5 or the pelvis, using all-pedicle screw instrumentation has not previously been reported. In this retrospective study, we compared nonambulatory patients undergoing surgery at two centres: one that routinely instrumented to L5 and the other to the pelvis. Methods. In all, 91 nonambulatory patients with neuromuscular scoliosis were included. All underwent surgery using bilateral, segmental, pedicle screw instrumentation. A total of 40 patients underwent fusion to L5 and 51 had their fixation extended to the pelvis. The two groups were assessed for differences in terms of clinical and radiological findings, as well as complications. Results. The main curve (MC) was a mean of 90° (40° to 141°) preoperatively and 46° (15° to 82°) at two-year follow-up in the L5 group, and 82° (33° to 116°) and 19° (1° to 60°) in the pelvic group (p < 0.001 at follow-up). Correction of MC and pelvic obliquity (POB) were statistically greater in the pelvic group (p < 0.001). There was no statistically significant difference in the operating time, blood loss, or complications. Loss of MC correction (> 10°) was more common in patients fixated to the pelvis (23% vs 3%; p = 0.032), while loss of pelvic obliquity correction was more frequent in the L5 group (25% vs 0%; p = 0.007). Risk factors for loss of correction (either POB or MC) included preoperative coronal imbalance (> 50 mm, odds ratio (OR) 11.5, 95%confidence interval (CI) 2.0 to 65; p = 0.006) and postoperative sagittal imbalance (> 25 mm, OR 11.0, 95% CI1.9 to 65; p = 0.008). Conclusion. We found that patients undergoing pelvic fixation had a greater correction of MC and POB. The rate of complications was not different. Preoperative coronal and postoperative sagittal imbalance were associated with increased risks of loss of correction, regardless of extent of fixation. Therefore, we recommend pelvic fixation in all nonambulatory children with neuromuscular scoliosis where coronal or sagittal imbalance are present preoperatively. Cite this article: Bone Joint J 2020;102-B(2):261–267

Aims. To compare the rates of sagittal and coronal correction for all-pedicle screw instrumentation and hybrid instrumentation using sublaminar bands in the treatment of thoracic adolescent idiopathic scoliosis (AIS). Methods. We retrospectively reviewed the medical records of 124 patients who had undergone surgery in two centres for the correction of Lenke 1 or 2 AIS. Radiological evaluation was carried out preoperatively, in the early postoperative phase, and at two-year follow-up. Parameters measured included coronal Cobb angles and thoracic kyphosis. Postoperative alignment was compared after matching the cohorts by preoperative coronal Cobb angle, thoracic kyphosis, lumbar lordosis, and pelvic incidence. Results. A total of 179 patients were available for analysis. After matching, 124 patients remained (62 in each cohort). Restoration of thoracic kyphosis was significantly better in the sublaminar band group than in the pedicle screw group (from 23.7° to 27.5° to 34.0° versus 23.9° to 18.7° to 21.5°; all p < 0.001). When the preoperative thoracic kyphosis was less than 20°, sublaminar bands achieved a normal postoperative thoracic kyphosis, whereas pedicle screws did not. In the coronal plane, pedicle screws resulted in a significantly better correction than sublaminar bands at final follow-up (73.0% versus 59.7%; p < 0.001). Conclusion. This is the first study to compare sublaminar bands and pedicle screws for the correction of a thoracic AIS. We have shown that pedicle screws give a good coronal correction which is maintained at two-year follow-up. Conversely, sublaminar bands restore the thoracic kyphosis better while pedicle screws are associated with a flattening of the thoracic spine. In patients with preoperative hypokyphosis, sublaminar bands should be used to restore a proper sagittal profile. Cite this article: Bone Joint J 2020;102-B(3):376–382

Aims. To report the outcome of spinal deformity correction through anterior spinal fusion in wheelchair-bound patients with myelomeningocele. Methods. We reviewed 12 consecutive patients (7M:5F; mean age 12.4 years (9.2 to 16.8)) including demographic details, spinopelvic parameters, surgical correction, and perioperative data. We assessed the impact of surgery on patient outcomes using the Spina Bifida Spine Questionnaire and a qualitative questionnaire. Results. The mean follow-up was 5.4 years (2 to 14.9). Nine patients had kyphoscoliosis, two lordoscoliosis, and one kyphosis. All patients had a thoracolumbar deformity. Mean scoliosis corrected from 89.6° (47° to 151°) to 46.5° (17° to 85°; p < 0.001). Mean kyphosis corrected from 79.5° (40° to 135°) to 49° (36° to 65°; p < 0.001). Mean pelvic obliquity corrected from 19.5° (8° to 46°) to 9.8° (0° to 20°; p < 0.001). Coronal and sagittal balance restored to normal. Complication rate was 58.3% (seven patients) with no neurological deficits, implant failure, or revision surgery. The degree of preoperative spinal deformity, especially kyphosis and lordosis, correlated with increased blood loss and prolonged hospital/intensive care unit stay. The patients reported improvement in function, physical appearance, and pain after surgery. The parents reported decrease in need for everyday care. Conclusion. Anterior spinal fusion achieved satisfactory deformity correction with high perioperative complication rates, but no long-term sequelae among children with high level myelomeningocele. This resulted in physical and functional improvement and high reported satisfaction. Cite this article: Bone Joint J 2021;103-B(6):1133–1141

Aims. To describe the clinical, radiological, and functional outcomes in patients with isolated congenital thoracolumbar kyphosis who were treated with three-column osteotomy by posterior-only approach. Methods. Hospital records of 27 patients with isolated congenital thoracolumbar kyphosis undergoing surgery at a single centre were retrospectively analyzed. All patients underwent deformity correction which involved a three-column osteotomy by single-stage posterior-only approach. Radiological parameters (local kyphosis angle (KA), thoracic kyphosis (TK), lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), C7 sagittal vertical axis (C7 SVA), T1 slope, and pelvic incidence minus lumbar lordosis (PI-LL)), functional scores, and clinical details of complications were recorded. Results. The mean age of the study population was 13.9 years (SD 6.4). The apex of deformity was in thoracic, thoracolumbar, and lumbar spine in five, 14, and eight patients, respectively. The mean operating time was 178.4 minutes (SD 38.5) and the mean operative blood loss was 701.8 ml (SD 194.4). KA (preoperative mean 70.8° (SD 21.6°) vs final follow-up mean 24.7° (SD 18.9°); p < 0.001) and TK (preoperative mean -1.48° (SD 41.23°) vs final follow-up mean 24.28° (SD 17.29°); p = 0.005) underwent a significant change with surgery. Mean Scoliosis Research Society (SRS-22r) score improved after surgical correction (preoperative mean 3.24 (SD 0.37) vs final follow-up mean 4.28 (SD 0.47); p < 0.001) with maximum improvement in self-image and mental health domains. The overall complication rate was 26%, including two neurological and five non-neurological complications. Permanent neurological deficit was noted in one patient. Conclusion. Deformity correction employing three-column osteotomies by a single-stage posterior-only approach is safe and effective in treating isolated congenital thoracolumbar kyphosis. Cite this article: Bone Joint J 2021;103-B(7):1309–1316

Aims. The aim of this study was to determine the differences in spinal imaging characteristics between subjects with or without lumbar developmental spinal stenosis (DSS) in a population-based cohort. Methods. This was a radiological analysis of 2,387 participants who underwent L1-S1 MRI. Means and ranges were calculated for age, sex, BMI, and MRI measurements. Anteroposterior (AP) vertebral canal diameters were used to differentiate those with DSS from controls. Other imaging parameters included vertebral body dimensions, spinal canal dimensions, disc degeneration scores, and facet joint orientation. Mann-Whitney U and chi-squared tests were conducted to search for measurement differences between those with DSS and controls. In order to identify possible associations between DSS and MRI parameters, those who were statistically significant in the univariate binary logistic regression were included in a multivariate stepwise logistic regression after adjusting for demographics. Odds ratios (ORs) and 95% confidence intervals (CIs) were reported where appropriate. Results. Axial AP vertebral canal diameter (p < 0.001), interpedicular distance (p < 0.001), AP dural sac diameter (p < 0.001), lamina angle (p < 0.001), and sagittal mid-vertebral body height (p < 0.001) were significantly different between those identified as having DSS and controls. Narrower interpedicular distance (OR 0.745 (95% CI 0.618 to 0.900); p = 0.002) and AP dural sac diameter (OR 0.506 (95% CI 0.400 to 0.641); p < 0.001) were associated with DSS. Lamina angle (OR 1.127 (95% CI 1.045 to 1.214); p = 0.002) and right facet joint angulation (OR 0.022 (95% CI 0.002 to 0.247); p = 0.002) were also associated with DSS. No association was observed between disc parameters and DSS. Conclusion. From this large-scale cohort, the canal size is found to be independent of body stature. Other than spinal canal dimensions, abnormal orientations of lamina angle and facet joint angulation may also be a result of developmental variations, leading to increased likelihood of DSS. Other skeletal parameters are spared. There was no relationship between DSS and soft tissue changes of the spinal column, which suggests that DSS is a unique result of bony maldevelopment. These findings require validation in other ethnicities and populations. Level of Evidence: I (diagnostic study). Cite this article: Bone Joint J 2021;103-B(4):725–733

Aims. The aim of this study is to introduce and investigate the efficacy and feasibility of a new vertebral osteotomy technique, vertebral column decancellation (VCD), for rigid thoracolumbar kyphotic deformity (TLKD) secondary to ankylosing spondylitis (AS). . Patients and Methods. We took 39 patients from between January 2009 and January 2013 (26 male, 13 female, mean age 37.4 years, 28 to 54) with AS and a TLKD who underwent VCD (VCD group) and compared their outcome with 45 patients (31 male, 14 female, mean age 34.8 years, 23 to 47) with AS and TLKD, who underwent pedicle subtraction osteotomy (PSO group), according to the same selection criteria. The technique of VCD was performed at single vertebral level in the thoracolumbar region of AS patients according to classification of AS kyphotic deformity. Pre- and post-operative chin-brow vertical angle (CBVA), sagittal vertical axis (SVA) and sagittal Cobb angle in the thoracolumbar region were reviewed in the VCD and PSO groups. Intra- , post-operative and general complications were analysed in both group. Results. lf patients could lie on their backs and walk with horizontal vision and sagittal profile, radiographic parameters improved significantly post-operatively in both groups. No major acute complications such as death or complete paralysis occurred in either group. In the VCD group, five patients (12.8%) experienced complications such as severe CSF leak (n = 4), deep wound infection (n = 1) and in one patient a transient neurological deficit occurred. In the PSO group, eight patients (17.8%) suffered conditions such as severe CSF leak (n = 5), infections (n = 2) and sagittal translation at osteotomy site (n = 1). Scoliosis Research Society outcomes instrument (SRS-22) improved significantly in both groups. All patients achieved solid fusion at latest follow-up and no implant failures were noted in either group. Take home message: The VCD technique is a new, safe and effective strategy for correction of rigid TLKD in AS patients. The main advantage of the new correction mechanism is that it achieved a satisfactory correction by controlled anterior column opening and posterior column closing, avoiding the occurrence of sagittal translation. Cite this article: Bone Joint J 2016;98-B:672–8

Aims. To study the associations of lumbar developmental spinal stenosis (DSS) with low back pain (LBP), radicular leg pain, and disability. Methods. This was a cross-sectional study of 2,206 subjects along with L1-S1 axial and sagittal MRI. Clinical and radiological information regarding their demographics, workload, smoking habits, anteroposterior (AP) vertebral canal diameter, spondylolisthesis, and MRI changes were evaluated. Mann-Whitney U tests and chi-squared tests were conducted to search for differences between subjects with and without DSS. Associations of LBP and radicular pain reported within one month (30 days) and one year (365 days) of the MRI, with clinical and radiological information, were also investigated by utilizing univariate and multivariate logistic regressions. Results. Subjects with DSS had higher prevalence of radicular leg pain, more pain-related disability, and lower quality of life (all p < 0.05). Subjects with DSS had 1.5 (95% confidence interval (CI) 1.0 to 2.1; p = 0.027) and 1.8 (95% CI 1.3 to 2.6; p = 0.001) times higher odds of having radicular leg pain in the past month and the past year, respectively. However, DSS was not associated with LBP. Although, subjects with a spondylolisthesis had 1.7 (95% CI 1.1 to 2.5; p = 0.011) and 2.0 (95% CI 1.2 to 3.2; p = 0.008) times greater odds to experience LBP in the past month and the past year, respectively. Conclusion. This large-scale study identified DSS as a risk factor of acute and chronic radicular leg pain. DSS was seen in 6.9% of the study cohort and these patients had narrower spinal canals. Subjects with DSS had earlier onset of symptoms, more severe radicular leg pain, which lasted for longer and were more likely to have worse disability and poorer quality of life. In these patients there is an increased likelihood of nerve root compression due to a pre-existing narrowed canal, which is important when planning surgery as patients are likely to require multi-level decompression surgery. Cite this article: Bone Joint J 2021;103-B(1):131–140

Aims. Patients with multiple myeloma (MM) develop deposits in the spine which may lead to vertebral compression fractures (VCFs). Our aim was to establish which spinopelvic parameters are associated with the greatest disability in patients with spinal myeloma and VCFs. Patients and Methods. We performed a retrospective cross-sectional review of 148 consecutive patients (87 male, 61 female) with spinal myeloma and analysed correlations between spinopelvic parameters and patient-reported outcome scores. The mean age of the patients was 65.5 years (37 to 91) and the mean number of vertebrae involved was 3.7 (1 to 15). Results. The thoracolumbar region was most commonly affected (109 patients, 73.6%), and was the site of most posterior vertebral wall defects (47 patients, 31.8%). Poorer Oswestry Disability Index scores correlated with an increased sagittal vertical axis (p = 0.006), an increased number of VCFs (p = 0.035) and sternal involvement (p = 0.012). Poorer EuroQol visual analogue scale scores correlated with posterior vertebral wall defects in the thoracolumbar region (p = 0.012). The sagittal vertical axis increased with the number of fractures and kyphosis in the thoracolumbar (p = 0.009) and lumbar (p < 0.001) regions. Conclusions. In MM, patients with VCFs have poorer clinical scores at presentation in the presence of sagittal imbalance. Outcome is particularly affected by multiple fractures in the thoracolumbar and lumbar regions and by failure to prevent kyphosis. Patients with MM should be screened for spinal lesions early. Cite this article: Bone Joint J 2016;98-B:1234–9

Ventral screw osteosynthesis is a common surgical method for treating fractures of the odontoid peg, but there is still no consensus about the number and diameter of the screws to be used. The purpose of this study was to develop a more accurate measurement technique for the morphometry of the odontoid peg (dens axis) and to provide a recommendation for ventral screw osteosynthesis. Images of the cervical spine of 44 Caucasian patients, taken with a 64-line CT scanner, were evaluated using the measuring software MIMICS. All measurements were performed by two independent observers. Intraclass correlation coefficients were used to measure inter-rater variability. The mean length of the odontoid peg was 39.76 mm (. sd. 2.68). The mean screw entry angle α was 59.45° (. sd. 3.45). The mean angle between the screw and the ventral border of C2 was 13.18° (. sd. 2.70), the maximum possible mean converging angle of two screws was 20.35° (. sd. 3.24). The measurements were obtained at the level of 66% of the total odontoid peg length and showed mean values of 8.36 mm (. sd. 0.84) for the inner diameter in the sagittal plane and 7.35 mm (. sd. 0.97) in the coronal plane. The mean outer diameter of the odontoid peg was 12.88 mm (. sd. 0.91) in the sagittal plane and 11.77 mm (. sd. 1.09) in the coronal plane. The results measured at the level of 90% of the total odontoid peg length were a mean of 6.12 mm (. sd. 1.14) for the sagittal inner diameter and 5.50 mm (. sd. 1.05) for the coronal inner diameter. The mean outer diameter of the odontoid peg was 11.10 mm (. sd.  1.0) in the sagittal plane and 10.00 mm (. sd. 1.07) in the coronal plane. In order to calculate the necessary screw length using 3.5 mm cannulated screws, 1.5 mm should be added to the measured odontoid peg length when anatomical reduction seems possible. The cross-section of the odontoid peg is not circular but slightly elliptical, with a 10% greater diameter in the sagittal plane. In the majority of cases (70.5%) the odontoid peg offers enough room for two 3.5 mm cannulated cortical screws. Cite this article: Bone Joint J 2013;95-B:536–42

Aims. Significant correction of an adolescent idiopathic scoliosis in the coronal plane through a posterior approach is associated with hypokyphosis. Factors such as the magnitude of the preoperative coronal curve, the use of hooks, number of levels fused, preoperative kyphosis, screw density, and rod type have all been implicated. Maintaining the normal thoracic kyphosis is important as hypokyphosis is associated with proximal junctional failure (PJF) and early onset degeneration of the spine. The aim of this study was to determine if coronal correction per se was the most relevant factor in generating hypokyphosis. Methods. A total of 95 patients (87% female) with a median age of 14 years were included in our study. Pre- and postoperative radiographs were measured and the operative data including upper instrumented vertebra (UIV), lower instrumented vertebra (LIV), metal density, and thoracic flexibility noted. Further analysis of the post-surgical coronal outcome (group 1 < 60% correction and group 2 ≥ 60%) were studied for their association with the postoperative kyphosis in the sagittal plane using univariate and multivariate logistic regression. Results. Of the 95 patients, 71.6% (68) had a thoracic correction of > 60%. Most (97.8%) had metal density < 80%, while thoracic flexibility > 50% was found in 30.5% (29). Preoperative hypokyphosis (< 20°) was present in 25.3%. A postoperative thoracic hypokyphosis was four times more likely to occur in patients with thoracic correction ≥ 60% (odds ratio (OR) 4.08; p = 0.005), after adjusting for confounding variables. This association was not affected by metal density, thoracic flexibility, LIV, UIV, age, or sex. Conclusion. Our study supports the ‘essential lordosis’ hypothesis of Roaf and Dickson, i.e. with a greater ability to translate the apical vertebra towards the midline, there is a commensurate lengthening of the anterior column due to the vertebral wedging. Cite this article: Bone Joint J 2020;102-B(4):513–518

Aims. We present the results of correcting a double or triple curve adolescent idiopathic scoliosis using a convex segmental pedicle screw technique. Patients and Methods. We reviewed 191 patients with a mean age at surgery of 15 years (11 to 23.3). Pedicle screws were placed at the convexity of each curve. Concave screws were inserted at one or two cephalad levels and two caudal levels. The mean operating time was 183 minutes (132 to 276) and the mean blood loss 0.22% of the total blood volume (0.08% to 0.4%). Multimodal monitoring remained stable throughout the operation. The mean hospital stay was 6.8 days (5 to 15). Results. The mean post-operative follow-up was 5.8 years (2.5 to 9.5). There were no neurological complications, deep wound infection, obvious nonunion or need for revision surgery. Upper thoracic scoliosis was corrected by a mean 68.2% (38% to 48%, p < 0.001). Main thoracic scoliosis was corrected by a mean 71% (43.5% to 8.9%, p < 0.001). Lumbar scoliosis was corrected by a mean 72.3% (41% to 90%, p < 0.001). No patient lost more than 3° of correction at follow-up. The thoracic kyphosis improved by 13.1° (-21° to 49°, p < 0.001); the lumbar lordosis remained unchanged (p = 0.58). Coronal imbalance was corrected by a mean 98% (0% to 100%, p < 0.001). Sagittal imbalance was corrected by a mean 96% (20% to 100%, p < 0.001). The Scoliosis Research Society Outcomes Questionnaire score improved from a mean 3.6 to 4.6 (2.4 to 4, p < 0.001); patient satisfaction was a mean 4.9 (4.8 to 5). . Conclusions. This technique carries low neurological and vascular risks because the screws are placed in the pedicles of the convex side of the curve, away from the spinal cord, cauda equina and the aorta. A low implant density (pedicle screw density 1.2, when a density of 2 represents placement of pedicle screws bilaterally at every instrumented segment) achieved satisfactory correction of the scoliosis, an improved thoracic kyphosis and normal global sagittal balance. Both patient satisfaction and functional outcomes were excellent. Cite this article: Bone Joint J 2017;99-B:1080–7

We describe 13 patients with cerebral palsy and lordoscoliosis/hyperlordosis of the lumbar spine who underwent a posterior spinal fusion at a mean age of 14.5 years (10.8 to 17.4) to improve sitting posture and relieve pain. The mean follow-up was 3.3 years (2.2 to 6.2). The mean pre-operative lumbar lordosis was 108. °. (80 to 150. °. ) and was corrected to 62. °. (43. °.  to 85. °. ); the mean thoracic kyphosis from 17. °. (-23. °. to 35. °. ) to 47. °. (25. °. to 65. °. ); the mean scoliosis from 82. °. (0. °. to 125. °. ) to 22. °. (0. °. to 40. °. ); the mean pelvic obliquity from 21. °. (0. °. to 38. °. ) to 3. °. (0. °. to 15. °. ); the mean sacral slope from 79. °. (54. °. to 90. °. ) to 50. °. (31. °. to 66. °. ). The mean pre-operative coronal imbalance was 5 cm (0 cm to 8.9 cm) and was corrected to 0.6 cm (0 to 3.2). The mean sagittal imbalance of -8 cm (-16 cm to 7.8 cm) was corrected to -1.6 cm (-4 cm to 2.5 cm). The mean operating time was 250 minutes (180 to 360 minutes) and intra-operative blood loss 0.8 of estimated blood volume (0.3 to 2 estimated blood volume). The mean intensive care and hospital stay were 3.5 days (2 to 8) and 14.5 days (10 to 27), respectively. Three patients lost a significant amount of blood intra-operatively and subsequently developed chest or urinary infections and superior mesenteric artery syndrome. An increased pre-operative lumbar lordosis and sacral slope were associated with increased peri-operative morbidity: scoliosis and pelvic obliquity were not. A reduced lumbar lordosis and increased thoracic kyphosis correlated with better global sagittal balance at follow-up. All patients and their parents reported excellent surgical outcomes. Lordoscoliosis and hyperlordosis are associated with significant morbidity in quadriplegic patients. They are rare deformities and their treatment is challenging. Sagittal imbalance is the major component: it can be corrected by posterior fusion of the spine with excellent functional results. Cite this article: Bone Joint J 2014;96-B:800–6