Aims. Magnetically controlled growing rods (MCGRs) allow non-invasive correction of the spinal deformity in the treatment of early-onset scoliosis. Conventional growing rod systems (CGRS) need repeated surgical distractions: these are associated with the effect of the ‘law of diminishing returns’. The primary aim of this study was to quantify this effect in MCGRs over sequential distractions. . Patients and Methods. A total of 35 patients with a maximum follow-up of 57 months were included in the study. There were 17 boys and 18 girls with a mean age of 7.4 years (2 to 14). True Distraction (TD) was determined by measuring the expansion gap on fluoroscopy. This was compared with Intended Distraction (ID) and expressed as the ‘T/I’ ratio. The T/I ratio and the Cobb angle were calculated at several time points during follow-up. Results. The mean follow-up was 30 months (6 to 57). There was a significant decrease in the mean T/I ratio over time (convex rod at 3 months 0.81, . sd. 0.58 vs 51 months 0.17, . sd . 0.16, p = 0.0001; concave rod at 3 months 0.93, . sd. 0.67 vs 51 months 0.18, . sd. 0.15, p = 0.0001). A linear decline of the mean T/I ratios was noted for both convex rods (r. 2. = 0.90, p = 0.004) and concave rods (r. 2. = 0.81, p = 0.015) over 51 months. At the 24-month follow-up stage, there was a significant negative correlation between the mean T/I ratio of the concave rod with weight (r = -0.59, p = 0.01), age (r = -0.59, p = 0.01), and BMI of the child (r = -0.54, p = 0.01). Conclusions. The ‘law of diminishing returns’ is also seen after serial distraction using MCGR. Compared to previously published data for CGRS, there is a gradual linear decline rather than a rapid initial decline in lengthening. In older, heavier children a reduced distraction ratio in the concave rod of the MCGR device is noted over time. Cite this article: Bone Joint J 2017;99-B:1658–64

Aims. The purpose of this retrospective study was to investigate the clinical relevance of increased facet joint distraction as a result of anterior cervical decompression and fusion (ACDF) for trauma. Patients and Methods. A total of 155 patients (130 men, 25 women. Mean age 42.7 years; 16 to 87) who had undergone ACDF between 1 January 2001 and 1 January 2016 were included in the study. Outcome measures included the Neck Disability Index (NDI) and visual analogue scale (VAS) for pain. Lateral cervical spine radiographs taken in the immediate postoperative period were reviewed to compare the interfacet distance of the operated segment with those of the facet joints above and below. Results. There was a statistically significant relationship between greater facet distraction and increased NDI and VAS pain scores. This was further confirmed by Spearman correlation, which showed evidence of a moderate correlation between both NDI score and facet joint distraction (Spearman correlation coefficient 0.34; p < 0.001) and VAS score and facet distraction (Spearman correlation coefficient 0.52; p < 0.001). Furthermore, there was a discernible transition point between outcome scores. Significantly worse outcomes, in terms of both NDI scores (17.8 vs 8.2; p < 0.001) and VAS scores (4.5 vs 1.3; p < 0.001), were seen with facet distraction of 3 mm or more. Patients who went on to have a posterior fusion also had increased NDI and VAS scores, independent of facet distraction. Conclusion. After undergoing ACDF for the treatment of cervical spine injury, patients with facet joint distraction of 3 mm or more have worse NDI and VAS pain scores. Cite this article: Bone Joint J 2018;100-B:1201–7

Aims. The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs). Methods. We undertook a retrospective review of skeletally mature patients who had undergone fusion for an EOS, which had been previously treated using either TGRs or MCGRs. Measured outcomes included sequential coronal T1 to S1 height and major curve (Cobb) angle on plain radiographs and any complications requiring unplanned surgery before final fusion. Results. We reviewed 43 patients (63% female) with a mean age of 6.4 years (SD 2.6) at the index procedure, and 12.2 years (SD 2.2) at final fusion. Their mean follow-up was 8.1 years (SD 3.4). A total of 16 patients were treated with MCGRs and 27 with TGRs. The mean number of distractions was 7.5 in the MCGR group and ten in the TGR group (p = 0.471). The mean interval between distractions was 3.4 months in the MCGR group and 8.6 months in the TGR group (p < 0.001). The mean Cobb angle had improved by 25.1° in the MCGR group and 23.2° in TGR group (p = 0.664) at final follow-up. The mean coronal T1 to S1 height had increased by 16% in the MCGR group and 32.9% in TGR group (p = 0.001), although the mean T1 to S1 height achieved at final follow-up was similar in both. Unplanned operations were needed in 43.8% of the MCGR group and 51.2% of TGR group (p = 0.422). Conclusion. In this retrospective, single-centre review, there were no significant differences in major curve correction or gain in spinal height at fusion. Although the number of planned procedures were fewer in patients with MCGRs, the rates of implant-related complications needing unplanned revision surgery were similar in the two groups. Cite this article: Bone Joint J 2022;104-B(2):257–264

Aims. The aim of this study was to compare outcomes after growth-friendly treatment for early-onset scoliosis (EOS) between patients with skeletal dysplasias versus those with other syndromes. Methods. We retrospectively identified 20 patients with skeletal dysplasias and 292 with other syndromes (control group) who had completed surgical growth-friendly EOS treatment between 1 January 2000 and 31 December 2018. We compared radiological parameters, complications, and health-related quality of life (HRQoL) at mean follow-up of 8.6 years (SD 3.3) in the dysplasia group and 6.6 years (SD 2.6) in the control group. Results. Mean major curve correction per patient did not differ significantly between the dysplasia group (43%) and the control group (28%; p = 0.087). Mean annual spinal height increase was less in the dysplasia group (9.3 mm (SD 5.1) than in the control group (16 mm (SD 9.2); p < 0.001). Mean annual spinal growth adjusted to patient preoperative standing height during the distraction period was 11% in the dysplasia group and 14% in the control group (p = 0.070). The complication rate was 1.6 times higher (95% confidence interval (CI) 1.3 to 2.0) in the dysplasia group. The following complications were more frequent in the dysplasia group: neurological injury (rate ratio (RR) 5.1 (95% CI 2.3 to 11)), deep surgical site infection (RR 2.2 (95% CI 1.2 to 4.1)), implant-related complications (RR 2.0 (95% CI 1.5 to 2.7)), and unplanned revision (RR 1.8 (95% CI 1.3 to 2.5)). Final fusion did not provide additional spinal height compared with watchful waiting (p = 0.054). There were no significant differences in HRQoL scores between the groups. Conclusion. After growth-friendly EOS treatment, patients with skeletal dysplasias experienced a higher incidence of complications compared to those with other syndromes. Surgical growth-friendly treatment for skeletal dysplasia-associated EOS should be reserved for patients with severe, progressive deformities that are refractory to nonoperative treatment. Cite this article: Bone Joint J 2024;106-B(6):596–602

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

Conventional growing rods are the most commonly used distraction-based devices in the treatment of progressive early-onset scoliosis. This technique requires repeated lengthenings with the patient anaesthetised in the operating theatre. We describe the outcomes and complications of using a non-invasive magnetically controlled growing rod (MCGR) in children with early-onset scoliosis. Lengthening is performed on an outpatient basis using an external remote control with the patient awake. Between November 2009 and March 2011, 34 children with a mean age of eight years (5 to 12) underwent treatment. The mean length of follow-up was 15 months (12 to 18). In total, 22 children were treated with dual rod constructs and 12 with a single rod. The mean number of distractions per patient was 4.8 (3 to 6). The mean pre-operative Cobb angle was 69° (46° to 108°); this was corrected to a mean 47° (28° to 91°) post-operatively. The mean Cobb angle at final review was 41° (27° to 86°). The mean pre-operative distance from T1 to S1 was 304 mm (243 to 380) and increased to 335 mm (253 to 400) in the immediate post-operative period. At final review the mean distance from T1 to S1 had increased to 348 mm (260 to 420). Two patients developed a superficial wound infection and a further two patients in the single rod group developed a loss of distraction. In the dual rod group, one patient had pull-out of a hook and one developed prominent metalwork. Two patients had a rod breakage; one patient in the single rod group and one patient in the dual rod group. Our early results show that the MCGR is safe and effective in the treatment of progressive early-onset scoliosis with the avoidance of repeated surgical lengthenings. Cite this article: Bone Joint J 2013;95-B:75–80

Aims. The aim of this study was to compare the outcomes of surgery using growing rods in patients with severe versus moderate early-onset scoliosis (EOS). Patients and Methods. A review of a multicentre EOS database identified 107 children with severe EOS (major curve ≥ 90°) treated with growing rods before the age of ten years with a minimum follow-up of two years and three or more lengthening procedures. From the same database, 107 matched controls with moderate EOS were identified. Results. The mean preoperative major curve was 101° (90 to 139) in the severe group and 67° (33° to 88°) in the moderate group (p < 0.001), which was corrected at final follow-up to 57° (10° to 96°) in the severe group and 40° (3° to 85°) in the moderate group (p < 0.001). T1-S1 height increased by a mean of 54 mm (-8 to 131) in the severe group and 27 mm (-4 to 131) in the moderate group at the initial surgery (p < 0.001), and by 50 mm (-17 to 200) and 54 mm (-11 to 212), respectively, during distraction (p = 0.84). The mean number of complications per patient was 2.6 (0 to 14) in the severe group and 1.9 (0 to 10) in the moderate group (p = 0.040). Five patients (4.7%) in the severe group and three (2.8%) in the moderate group developed a neurological deficit postoperatively (p = 0.47). Conclusion. Severe EOS can be treated effectively using growing rods, but the risk of complications is high. Cite this article: Bone Joint J 2018;100-B:772–9

Aims. We undertook a prospective non-randomised radiological study to evaluate the preliminary results of using magnetically-controlled growing rods (MAGEC System, Ellipse technology) to treat children with early-onset scoliosis. Patients and Methods. Between January 2011 and January 2015, 19 children were treated with magnetically-controlled growing rods (MCGRs) and underwent distraction at three-monthly intervals. The mean age of our cohort was 9.1 years (4 to 14) and the mean follow-up 22.4 months (5.1 to 35.2). Of the 19 children, eight underwent conversion from traditional growing rods. Whole spine radiographs were carried out pre- and post-operatively: image intensification was used during each lengthening in the outpatient department. The measurements evaluated were Cobb angle, thoracic kyphosis, proximal junctional kyphosis and spinal growth from T1 to S1. Results. The mean pre-, post-operative and latest follow-up Cobb angles were 62° (37.4 to 95.8), 45.1° (16.6 to 96.2) and 43.2° (11.9 to 90.5), respectively (p < 0.05). The mean pre-, post-operative and latest follow-up T1-S1 lengths were 288.1 mm (223.2 to 351.7), 298.8 mm (251 to 355.7) and 331.1 mm (275 to 391.9), respectively (p < 0.05). In all, three patients developed proximal pull-out of their fixation and required revision surgery: there were no subsequent complications. There were no complications of outpatient distraction. Conclusions. Our study shows that MCGRs provide stable correction of the deformity in early-onset scoliosis in both primary and revision procedures. They have the potential to reduce the need for multiple operations and thereby minimise the potential complications associated with traditional growing rod systems. Cite this article: Bone Joint J 2016;98-B:1240–47

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

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The outcome following the development of neurological complications after corrective surgery for scoliosis varies from full recovery to a permanent deficit. This study aimed to assess the prognosis and recovery of major neurological deficits in these patients, and to determine the risk factors for non-recovery, at a minimum follow-up of two years.

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Spinal deformity surgery carries the risk of neurological injury. Neurophysiological monitoring allows early identification of intraoperative cord injury which enables early intervention resulting in a better prognosis. Although multimodal monitoring is the ideal, resource constraints make surgeon-directed intraoperative transcranial motor evoked potential (TcMEP) monitoring a useful compromise. Our experience using surgeon-directed TcMEP is presented in terms of viability, safety, and efficacy.

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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.

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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).

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The primary aim of this study was to evaluate the performance and safety of magnetically controlled growth rods in the treatment of early onset scoliosis. Secondary aims were to evaluate the clinical outcome, the rate of further surgery, the rate of complications, and the durability of correction.

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Magnetically controlled growing rod (MCGR) systems use non-invasive spinal lengthening for the surgical treatment of early-onset scoliosis (EOS). The primary aim of this study was to evaluate the performance of these devices in the prevention of progression of the deformity. A secondary aim was to record the rate of complications.

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To address the natural history of severe post-tuberculous (TB) kyphosis, with focus upon the long-term neurological outcome, occurrence of restrictive lung disease, and the effect on life expectancy.

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The aim of this study was to determine if positive Waddell signs were related to patients’ demographics or to perception of their quality of life.

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We present a case series of five patients who had revision surgery following magnetic controlled growing rods (MGCR) for early onset scoliosis. Metallosis was found during revision in four out of five patients and we postulated a mechanism for rod failure based on retrieval analysis.

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We compared the clinical and radiological outcomes of using a polyetheretherketone cage with (TiPEEK) and without a titanium coating (PEEK) for instrumented transforaminal lumbar interbody fusion (TLIF).

Minimal clinically important differences (MCID) in the scores of patient-reported outcome measures allow clinicians to assess the outcome of intervention from the perspective of the patient. There has been significant variation in their absolute values in previous publications and a lack of consistency in their calculation.

The purpose of this study was first, to establish whether these values, following spinal surgery, vary depending on the surgical intervention and their method of calculation and secondly, to assess whether there is any correlation between the two external anchors most frequently used to calculate the MCID.

We carried out a retrospective analysis of prospectively gathered data of adult patients who underwent elective spinal surgery between 1994 and 2009. A total of 244 patients were included. There were 125 men and 119 women with a mean age of 54 years (16 to 84); the mean follow-up was 62 months (6 to 199) The MCID was calculated using three previously published methods.

Our results show that the value of the MCID varies considerably with the operation and its method of calculation. There was good correlation between the two external anchors. The global outcome tool correlated significantly better.

We conclude that consensus needs to be reached on the best method of calculating the MCID. This then needs to be defined for each spinal procedure. Using a blanket value for the MCID for all spinal procedures should be avoided.

Cite this article: Bone Joint J 2015;97-B:366–71.