Aims

Closed suction subfascial drainage is widely used after instrumented posterior spinal fusion in patients with a spinal deformity. The aim of this study was to determine the effect of this wound drainage on the outcomes in patients with adolescent idiopathic scoliosis (AIS). This was a further analysis of a randomized, multicentre clinical trial reporting on patients after posterior spinal fusion using segmental pedicle screw instrumentation. In this study the incidence of deep surgical site infection (SSI) and chronic postoperative pain at two years’ follow-up are reported.

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.

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Spinopelvic pathology increases the risk for instability following total hip arthroplasty (THA), yet few studies have evaluated how pathology varies with age or sex. The aims of this study were: 1) to report differences in spinopelvic parameters with advancing age and between the sexes; and 2) to determine variation in the prevalence of THA instability risk factors with advancing age.

In recent years, machine learning (ML) and artificial neural networks (ANNs), a particular subset of ML, have been adopted by various areas of healthcare. A number of diagnostic and prognostic algorithms have been designed and implemented across a range of orthopaedic sub-specialties to date, with many positive results. However, the methodology of many of these studies is flawed, and few compare the use of ML with the current approach in clinical practice. Spinal surgery has advanced rapidly over the past three decades, particularly in the areas of implant technology, advanced surgical techniques, biologics, and enhanced recovery protocols. It is therefore regarded an innovative field. Inevitably, spinal surgeons will wish to incorporate ML into their practice should models prove effective in diagnostic or prognostic terms. The purpose of this article is to review published studies that describe the application of neural networks to spinal surgery and which actively compare ANN models to contemporary clinical standards allowing evaluation of their efficacy, accuracy, and relatability. It also explores some of the limitations of the technology, which act to constrain the widespread adoption of neural networks for diagnostic and prognostic use in spinal care. Finally, it describes the necessary considerations should institutions wish to incorporate ANNs into their practices. In doing so, the aim of this review is to provide a practical approach for spinal surgeons to understand the relevant aspects of neural networks.

Cite this article: Bone Joint J 2021;103-B(9):1442–1448.

Ultrasound can be used to outline the spinous processes and the laminae, and thus to measure axial rotation. Using our own technique, we measured vertebral rotation in 47 patients with idiopathic scoliosis. There was a strong linear relationship between the Cobb angle and the rotation of the apical vertebra in untreated patients, but this relationship was lost in patients who had had brace treatment. Vertebral rotation can easily be measured by ultrasound. This is a harmless and fairly rapid investigation which can be used at routine follow-up examination of patients with idiopathic scoliosis

Aims

The aim of this study was to evaluate whether, after correction of an adolescent idiopathic scoliosis (AIS), leaving out the subfascial drain gives results that are no worse than using a drain in terms of total blood loss, drop in haemoglobin level, and opioid consumption.

A prospective study to investigate changes in the rib hump or rib deformity after correction of the lateral curvature in adolescent idiopathic scoliosis is reported. The operative treatment for 47 patients was by a Harrington distraction rod and posterior fusion. Before operation and at follow-up, measurements of the Cobb angle, of vertebral rotation, and of the rib deformity were taken. Despite operative correction of the lateral curve, there was a progression of the rib deformity in 64% of the cases after four years. Correction of the lateral curve may thus have no effect on vertebral rotation and cannot be guaranteed to effect a permanent reduction of the rib hump

We investigated 21 pairs of twins for zygosity and idiopathic scoliosis. DNA fingerprinting confirmed that 13 pairs were monozygotic and eight were dizygotic. There was concordance for idiopathic scoliosis in 92.3% of monozygotic and 62.5% of dizygotic twins. Of the 12 pairs of monozygotic twins concordant for idiopathic scoliosis, six showed discordant curve patterns but eight had differences in Cobb angle of less than 10°. Seven of the ten pairs of monozygotic twins had similar back shapes. Our findings suggest that there is a genetic factor in the aetiology of idiopathic scoliosis; they also indicate that there is a genetic factor in both the severity of the curve and the general shape of the back

Late-onset idiopathic scoliosis is associated with a rib hump in the thoracic region, and surgery is indicated when this deformity becomes unacceptable. Fifty patients with this deformity were treated by the Leeds procedure, which consists of segmental wiring to a kyphotically-contoured square-ended Harrington rod; this procedure not only derotates the spine but restores the natural thoracic kyphosis, thus avoiding subsequent buckling. All patients were followed up for a minimum of two years. Forty-two of these, who had a pre-operative Cobb angle of less than 60 degrees, were treated by one-stage instrumentation and fusion, while the remaining eight with greater curves underwent preliminary anterior multiple discectomy to provide flexibility with shortening. Postoperative loss of correction was not observed and there were no neurological complications

We reviewed 77 unfused and 91 fused patients with idiopathic scoliosis who first attended between 1949 and 1965. Both groups were re-examined at least 10 years after reaching skeletal maturity, with attention to progression of the Cobb angle, increased in vertebral rotation, back pain and psychosocial problems. We found that spinal fusion protects the scoliotic spine from further deterioration during adult life except for those with severe curves and marked rotation. Fusion also significantly reduced the incidence of severe pain and allowed patients to carry out heavy physical work, but did not confer complete immunity from backache. Surgery improved the appearance, but patients were not always completely satisfied with the cosmetic result

We have treated 101 patients with scoliosis secondary to muscular dystrophy over a 13-year period; 64 had Duchenne’s muscular dystrophy, 33 spinal muscular atrophy and four congenital muscular dystrophy. The patients underwent a modified Luque (87) or Harrington-Luque instrumentation (14) combined with a limited Moe fusion in all except 27 cases. A mean of 13 levels was instrumented. The mean preoperative sitting Cobb angle was 84° (10 to 150) and the mean postoperative angle 40° (52% correction). Most patients (96%) were able to discard their braces and there was a high level of patient satisfaction (89.6%). Less correction was seen for severe curves, and there was a greater recurrence of postoperative pelvic tilt in those patients not instrumented to the sacrum. Although the incidence of minor or temporary complications was high, these occurred chiefly in the early high-risk patients with very severe curves and considerable pre-existing immobility

Aims

Adverse spinal motion or balance (spine mobility) and adverse pelvic mobility, in combination, are often referred to as adverse spinopelvic mobility (SPM). A stiff lumbar spine, large posterior standing pelvic tilt, and severe sagittal spinal deformity have been identified as risk factors for increased hip instability. Adverse SPM can create functional malposition of the acetabular components and hence is an instability risk. Adverse pelvic mobility is often, but not always, associated with abnormal spinal motion parameters. Dislocation rates for dual-mobility articulations (DMAs) have been reported to be between 0% and 1.1%. The aim of this study was to determine the early survivorship from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) of patients with adverse SPM who received a DMA.

Moire topography was added to school scoliosis screening in Singapore in 1982. The results from 1342 topographs, assessed in isolation, were used to study the accuracy of the method in predicting the radiographic location and magnitude of scoliotic curves. Accuracy in identifying the site of the curve was 68% in the thoracic spine, 54% in the thoracolumbar spine, and 15% in the lumbar region. There were 12.7% false-positive results and 4.3% false negatives. Of patients with a deviation of one moire fringe, 76.5% had a curve of 15 degrees or less; of those with a deviation of four moire fringes, 69% had a curve greater than 26 degrees. The prediction of the Cobb angle was less accurate when there was a deviation of two or three fringes. It is suggested that moire topography as a screening device should be reserved for use in the second tier of screening, since the forward-bending test is an effective and cheap method for the first tier of a mass school-screening programme

Spinal fusion, ending caudally at L5 rather than at the sacrum, is recommended for selected patients with scoliosis due to Duchenne muscular dystrophy. We present a retrospective review of 48 patients operated on for this condition. Patients having spinal curvature with a Cobb angle of less than 40° and with less than 10° between a line tangential to the superior margins of both iliac crests and a line perpendicular to the spinous processes of L4 and L5, were fused to L5 (38 patients); patients not meeting these criteria were fused to the sacrum (10 patients). Spinal and sitting obliquity increased in patients fused to L5, rather than to the sacrum, but the severity of the worsening obliquity was significantly greater in patients in whom the apex of the curve was below L1. Two of the ten latter patients required revision procedures for worsening obliquity when their pulmonary function deteriorated to less than 25% of predicted values. We recommend fusion to the sacrum for scoliosis in Duchenne muscular dystrophy, especially for patients with an apex to their curve below L1

We have investigated the effect of multisegmental spinal fusion on the long-term functional and radiological outcome in patients with scoliosis. We compared these patients both with those whose spine had not been fused, and with a control group. We studied 68 patients with idiopathic scoliosis (34 operative and 34 non-operative) who had been followed up for a minimum of five years after treatment. They were matched for age (mean 44 years) and Cobb angle (mean 54°) at follow-up. An age- and gender-matched control group of 34 subjects was also recruited. All participants completed a questionnaire to assess spinal function and to grade the severity of back pain using a numerical rating scale. Radiographs of the spine were taken in the patients with scoliosis and lumbar degenerative changes were recorded. The spinal function scores for the patients with scoliosis who had had a fusion were similar to those who had not. Both scoliosis groups, however, had lower scores than the control group (p < 0.001). The frequency and severity of back pain were lower for patients with scoliosis and fusion than for those without, but higher for both scoliosis groups compared with the control group. Radiographs showed similar degenerative changes in both scoliosis groups

We studied 29 girls and one boy with adolescent idiopathic scoliosis who were at Risser grade 0 at the time of posterior spinal fusion and were followed until maturity (mean 7.8 years). We used serial radiographs to measure the ratio of disc to vertebral height in the fused segments and to detect differential anterior spinal growth and assess its effect on scoliosis, vertebral rotation, kyphosis, and rib-vertebral-angle difference (RVAD). From one year after surgery to the latest review, the percentage anterior disc height decreased by nearly one-half and the percentage posterior disc height by nearly one-third in the fused segments (p < 0.001). There was a 4 degree increase in mean Cobb angle (p < 0.001), 11 patients (37%) having an increase of between 6 degrees and 10 degrees. There was a significant increase in mean apical rotation by 2 degrees (p = 0.003), and four patients (13%) had an increase of between 6 degrees and 16 degrees. There was little change in kyphosis. There was an increase in mean RVAD by 4 degrees (p = 0.003), seven patients (23%) showing a reduction by 1 degree to 7 degrees, and 11 (37%) increases of between 6 degrees and 16 degrees. Spinal growth occurs after posterior fusion in adolescents who are skeletally immature, as a result of continued anterior vertebral growth. There is some progression of scoliosis, vertebral rotation, and RVAD, but little change in kyphosis. The increase in deformity is not enough to warrant the use of combined anterior and posterior fusion. The findings are relevant to the management of progressive curves, the timing and extent of surgery, and the prognosis for progression of deformity in this group of patients

Aims

Pelvic incidence (PI) is a position-independent spinopelvic parameter traditionally used by spinal surgeons to determine spinal alignment. Its relevance to the arthroplasty surgeon in assessing patient risk for total hip arthroplasty (THA) instability preoperatively is unclear. This study was undertaken to investigate the significance of PI relative to other spinopelvic parameter risk factors for instability to help guide its clinical application.

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