The development of spinal deformity in children with underlying neurodisability can affect their ability to function and impact on their quality of life, as well as compromise provision of nursing care. Patients with neuromuscular spinal deformity are among the most challenging due to the number and complexity of medical comorbidities that increase the risk for severe intraoperative or postoperative complications. A multidisciplinary approach is mandatory at every stage to ensure that all nonoperative measures have been applied, and that the treatment goals have been clearly defined and agreed with the family. This will involve input from multiple specialities, including allied healthcare professionals, such as physiotherapists and wheelchair services. Surgery should be considered when there is significant impact on the patients’ quality of life, which is usually due to poor sitting balance, back or costo-pelvic pain, respiratory complications, or problems with self-care and feeding. Meticulous preoperative assessment is required, along with careful consideration of the nature of the deformity and the problems that it is causing. Surgery can achieve good curve correction and results in high levels of satisfaction from the patients and their caregivers. Modern modular posterior instrumentation systems allow an effective deformity correction. However, the risks of surgery remain high, and involvement of the family at all stages of decision-making is required in order to balance the risks and anticipated gains of the procedure, and to select those patients who can mostly benefit from spinal correction.

Aims

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.

Aims. 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. Methods. We carried out a retrospective review of a single surgeon’s prospectively maintained database of cases in which TcMEP monitoring had been used between 2010 and 2017. The upper limbs were used as the control. A true alert was recorded when there was a 50% or more loss of amplitude from the lower limbs with maintained upper limb signals. Patients with true alerts were identified and their case history analyzed. Results. Of the 299 cases reviewed, 279 (93.3%) had acceptable traces throughout and awoke with normal clinical neurological function. No patient with normal traces had a postoperative clinical neurological deficit. True alerts occurred in 20 cases (6.7%). The diagnoses of the alert group included nine cases of adolescent idiopathic scoliosis (AIS) (45%) and six of congenital scoliosis (30%). The incidence of deterioration based on diagnosis was 9/153 (6%) for AIS, 6/30 (20%) for congenital scoliosis, and 2/16 (12.5%) for spinal tuberculosis. Deterioration was much more common in congenital scoliosis than in AIS (p = 0.020). Overall, 65% of alerts occurred during rod instrumentation: 15% occurred during decompression of the internal apex in vertebral column resection surgery. Four alert cases (20%) awoke with clinically detectable neurological compromise. Conclusion. Surgeon-directed TcMEP monitoring has a 100% negative predictive value and allows early identification of physiological cord distress, thereby enabling immediate intervention. In resource constrained environments, surgeon-directed TcMEP is a viable and effective method of intraoperative spinal cord monitoring. Level of evidence: III. Cite this article: Bone Joint J 2021;103-B(3):547–552

Aims

The aim of this retrospective study was to compare the correction achieved using a convex pedicle screw technique and a low implant density achieved using periapical concave-sided screws and a high implant density. We hypothesized that there would be no difference in outcome between the two techniques.

Aims

High-grade dysplastic spondylolisthesis is a disabling disorder for which many different operative techniques have been described. The aim of this study is to evaluate Scoliosis Research Society 22-item (SRS-22r) scores, global balance, and regional spino-pelvic alignment from two to 25 years after surgery for high-grade dysplastic spondylolisthesis using an all-posterior partial reduction, transfixation technique.

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

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This study aimed to explore whether intraoperative nerve monitoring can identify risk factors and reduce the incidence of nerve injury in patients with high-riding developmental dysplasia.

There is an inherent risk of iatrogenic new neurological deficit (NND) arising at the spinal cord, cauda equina and nerve root during spinal surgery. Intraoperative neurophysiological monitoring (IONM) can be employed to preserve spinal cord function during spinal surgery. IONM techniques include somatosensory and motor evoked potentials, amongst others. A Canadian survey of 95 spinal surgeons showed that 62.1% used IONM and a similar survey in France of 117 spinal surgeons showed that only 36% used IONM. Unavailability was a common reason for its disuse. Current literature by the British Society of Clinical Neurophysiology has outlined the importance of IONM in preventing NND and the need for the implementation of guidelines for IONM. The lack of an established guideline has resulted in a varied approach in the use of IONM in England. There has been no previous attempt to ascertain the current use of IONM in England. Our study is aimed at assessing the variability of the use of IONM in England as well as identifying the rationale amongst surgeons that dictate their use of IONM. We are in the process of investigating the indications of use of IONM for cervical and lumbar spine procedures in 252 spinal surgeons from 33 hospitals with spinal services. Our survey will illustrate the current use of IONM in spinal surgery in England. It will highlight some of the reasons for the variability of use of IONM and identify factors that can contribute to a more standardised use of IONM in spinal surgery

Aims

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.

Aims

The surgical treatment of tuberculosis (TB) of the spine consists of debridement and reconstruction of the anterior column. Loss of correction is the most significant challenge. Our aim was to report the outcome of single-stage posterior surgery using bone allografts in the management of this condition.

Background:. Spinal deformity surgery carries the risk of loss of neurological function which may be permanent. Although the overall the incidence is low it is much higher in complex congenital deformities or those with pre-existing myelopathy. Intra-operative spinal cord monitoring allows this risk to be reduced by providing feedback to the surgeon while the corrective manoeuvres are performed. Although ideally a trained technician with multimodal monitoring is recommended, it is often not an option in a resource limited environment and surgeon operated technology is used. Aim:. to evaluate the use of surgeon operated trans-cranial motor evoked potentials (tcMEP) in spinal deformity surgery. Methods:. A retrospective review was conducted on a single surgeon series of 108 consecutive cases utilising the NIM system (Medtronic). Percutaneous needles were employed in the scalp, both hands and feet to allow the upper limbs to act as controls. Forty-nine patients were 13 years old or less, 47 were 14–18, and 12 adults. The cohort consisted of 54 AIS, 27 neuromuscular scoliosis, 14 congenital, 2 old TB and 11 miscellaneous. The vast majority were posterior based procedures. Results:. In 4 cases initial traces could not be obtained. One was a severe myelopathy and further efforts to monitor were abandoned. In one case the anaesthetist had broken protocol and once converted to TIVA the traces improved. Two others were poor initially but improved as the case progressed. In 8 cases intra-operative traces were lost. One was thought to be due to hypothermia and the patient woke intact. Two were unrelated to surgical intervention and recovered spontaneously with patients waking intact. Four cases deteriorated during the corrective manoeuvre (one delayed) and recovered with reduction of correction. One case required removal of instrumentation after repeated loss each time rods were inserted and awoke with a weak leg but recovered and was re-operated two weeks later. Conclusion:. Surgeon operated tcMEP's allows feedback in terms of safety of deformity correction with a 100% negative predictive value and an 8% incidence of signal loss during correction allowing immediate remedial action

To determine whether neurophysiological electrical pedicle testing (EPT) is a useful aid in the detection of malpostioned pedicle screw tracts. EPT data from 246 screws in 32 spinal operations on 32 patients over a 5 year period (2009–2014) were recorded and analysed. In addition to physical palpation, a ball-tipped electrode delivered stimuli and the output was recorded by evoked electromyogram (EMG). When breach threshold values were recorded, the surgeon rechecked the tract for breaches and responded appropriately. In addition, standard motor evoked potential (MEP) and sensory evoked potential(SEP) spinal cord monitoring was performed. There were 24(9.8%) pedicle breaches by tract testing and 8(3.3%) by screw testing. In 11 instances in 7 patients where the tract testing showed a breach, the tract was redirected and subsequent screw testing showed adequate integrity of the pedicle. The total time for tract and screw testing was 25 seconds. There were no associated changes in MEP or SEP monitoring with any of the recorded pedicle breaches and none of the patients had any post-operative neurological deficit. EPT for the pedicle screw and tract is a safe, simple, practical and reliable technique which improves the accuracy of screw placement. Further studies would be required to confirm (and possibly revise) the threshold levels and to demonstrate whether EPT reduces the risk of misplaced screws or post-operative neurological deficit

Summary Statement. The spinal cord showed marked sensibility to acute compression causing complete and irreversible injury. On the contrary, the spinal cord has more ability for adaptation to slow progressive compression mechanisms having the possibility of neural recovery after compression release. Introduction. The aim of this experimental study was to establish, by means of neurophysiologic monitoring, the degree of compression needed to cause neurologic injury to the spinal cord, and analyze whether these limits are different making fast or slow compression. Material and Methods. Spinal cord was exposed from T7 to T11 in 5 domestic pigs with a mean weight of 35 kg. The T8 and T9 spinal roots were also exposed. A pair of sticks, attached to a precise compression device, was set up to both sides of the spinal cord between T8 and T9 roots. Sequentially, the sticks were approximated 0.5 mm every 2 minutes causing progressive spinal cord compression. An acute compression of the spinal cord was also reproduced by a 2.5 mm displacement of the sticks. Cord to cord motor evoked potentials were obtained with two epidural catheters, stimulating proximal to T6 and recording below the compression level, distal to T10, for each sequential approach of the sticks. Results. The mean width of the dural sac was 7.1 mm. For progressive compression, increasing latency and decreasing amplitude of the evoked potentials were observed after a mean displacement of the sticks of 3.2 ± 0.9 mm, the evoked potential finally disappearing after a mean displacement of 4.6 ± 1.2 mm. The potential returned 16.8 ± 3.2 minutes after the compression was stopped in every case. The evoked potentials immediately disappeared after an acute compression 2.5 ± 0.3 mm, without any sign of recovering after 30 minutes. Conclusion. The proposed experimental model replicates the mechanism of a spinal cord injury caused by medially displaced screws into the spinal canal, causing therefore lateral compression to the spinal cord. The spinal cord showed marked sensibility to acute compression, which caused complete and irreversible injury. On the contrary, the spinal cord has more ability for adaptation to progressive and slow compression mechanisms. From a clinical point of view, it seems mandatory to avoid maneuvers of rapid mobilization or acute, even minimal, contusions of the thoracic cord

Introduction. Changes in central nervous system (CNS) pathways controlling trunk and leg muscles in patients with low back pain(LBP) and lumbar radiculopathy have been observed and this study investigated whether surgery impacts upon these changes in the long term. Methods. 80 participants were recruited into the following groups: 25 surgery(S), 20 chronic LBP(CH), 14 spinal injection(SI), and 21 controls(C). Parameters of corticospinal control were examined before, at 6, 26 and 52 weeks following lumbar decompression surgery and equivalent intervals. Electromyographic(EMG) activity was recorded from tibialis anterior(TA), soleus(SOL), rectus abdominis(RA), external oblique(EO) and erector spinae(ES) muscles at the T12&L4 levels in response to transcranial magnetic stimulation of the motor cortex. Motor evoked potentials (MEP) and cortical silent periods(cSP) recruitment curves(RC) were analysed. Results. Trunk muscles in all patients had reduced raw EMG (P<0.001), increased motor thresholds (MTh;P<0.001) and MEP RC slopes. MTh in ESL4 correlated with back pain in all patients (r=0.201, P=0.016) and soleus MTh laterality with disability in surgery patients (r=0.49, P=0.018). S&SI patients displayed bilaterally increased soleus cSP (p<0.001), MEP latencies on the painful side (P<0.001), and cSP asymmetry (cSPA;P<0.001). cSPA resulted from abnormal soleus late responses on the painful side, indicating compromised agonist-antagonist control in patients with radiculopathy. In contrast to SI, surgery significantly reduced soleus cSPA and MEP latencies at 6 weeks (P≤0.034). Discussion. These results show long term changes in CNS control of trunk and leg muscles in radiculopathy and LBP, which are only partly reversed by surgery, and may provide future therapeutic targets to address the altered inhibitory processes within the brain. No conflicts of Interest. Sources of funding: The DISCS foundation. This abstract has not been previously published in whole or substantial part nor has it been presented previously at a national meeting

Objectives. To determine the limits of spinal displacement before the onset of neurophysiological changes during spinal surgery. Assessing if the type of force applied or the section of the adjacent nerve roots increases the tolerance to displacement. Methods. Experimental study in 21 domestic pigs. Three groups were established according to the displacing force applied to the cord: separation (group 1, n=7), root stump pull (group2, n=7) and torque (group3, n=7). Successive records of cord-to-cord motor evoked potential were obtained. The displacing force was removed immediately when neurophysiological changes observed. The experiment was repeated after sectioning the adjacent nerve roots. Results. The diameter of the dura in the study area was 7.2 ± 1 mm. Group 1: evoked potential changes appeared with displacement of 10.1 ± 1.6 mm with roots unharmed and 15.3 ± 4.7 mm (p <0.01) with section of four adjacent roots. Group 2: evoked potential disturbance at 17.5 ± 4.7 mm, which increased to 23.5 ± 2.1 mm (p <0.05) after cutting the two contralateral roots. Group 3: cord allowed torque of 95.3° ± 9.2 increasing to 112.4 ° ± 7.1 ° if the contralateral roots were cut. Except in two cases in group 3 (torsion), the potentials were normalized immediately after releasing the deforming force. Discussion. This experimental study shows that it is possible to surgically displace the medulla a distance superior to the diameter of the dura without detecting neurophysiological changes. The limits of cord displacement may be increased by the section of the adjacent nerve roots and if the tensile force is applied by traction of the root stumps. These findings support the neurological safety of spine deformity correction by isolated posterior approach, obviating the morbidity related to an additional anterior procedure

We report the results of vertebral column resection (VCR) for paediatric patients with spinal deformity. A total of 49 VCRs in paediatric patients from four university hospitals between 2005 and 2009 with a minimum two-year follow-up were retrospectively identified. After excluding single hemivertebral resections (n = 25) and VCRs performed for patients with myelomeningocele (n = 6), as well as spondylectomies performed for tumour (n = 4), there were 14 patients who had undergone full VCR at a mean age of 12.3 years (6.5 to 17.9). The aetiology was congenital scoliosis in five, neuromuscular scoliosis in three, congenital kyphosis in two, global kyphosis in two, adolescent idiopathic scoliosis in one and secondary scoliosis in one. A total of seven anteroposterior and seven posterolateral approaches were used.

The mean major curve deformity was 86° (67° to 120°) pre-operatively and 37° (17° to 80°) at the two-year follow-up; correction was a mean of 54% (18% to 86%) in the anteroposterior and 60% (41% to 70%) in the posterolateral group at the two-year follow-up (p = 0.53). The mean Scoliosis Research Society-24 total scores were 100 (92 to 108) for the anteroposterior and 102 (95 to 105) for the posterolateral group. There was one paraparesis in the anteroposterior group necessitating urgent re-decompression, with a full recovery.

Patients undergoing VCR are highly satisfied after a successful procedure.

We reviewed 31 consecutive patients with Friedreich’s ataxia and scoliosis. There were 24 males and seven females with a mean age at presentation of 15.5 years (8.6 to 30.8) and a mean curve of 51° (13° to 140°). A total of 12 patients had thoracic curvatures, 11 had thoracolumbar and eight had double thoracic/lumbar. Two patients had long thoracolumbar collapsing scoliosis with pelvic obliquity and four had hyperkyphosis. Left-sided thoracic curves in nine patients (45%) and increased thoracic kyphosis differentiated these deformities from adolescent idiopathic scoliosis. There were 17 patients who underwent a posterior instrumented spinal fusion at mean age of 13.35 years, which achieved and maintained good correction of the deformity. Post-operative complications included one death due to cardiorespiratory failure, one revision to address nonunion and four patients with proximal junctional kyphosis who did not need extension of the fusion. There were no neurological complications and no wound infections. The rate of progression of the scoliosis in children kept under simple observation and those treated with bracing was less for lumbar curves during bracing and similar for thoracic curves. The scoliosis progressed in seven of nine children initially treated with a brace who later required surgery. Two patients presented after skeletal maturity with balanced curves not requiring correction. Three patients with severe deformities who would benefit from corrective surgery had significant cardiac co-morbidities.

To establish the current practice of spinal cord monitoring in units carrying out scoliosis surgery in the UK. To illustrate the benefit of routinely monitoring motor evoked potentials (MEPs). Questionaire: Nationwide survey of spinal monitoring modalities used by spinal units carrying out deformity surgery. 10 out of 27 units routinely measure motor evoked potentials (MEPs), the remainder use only sensory potentials (SEPs). There is significant variability in use of monitoring around the UK and we have compared this to the practice elsewhere in the world. We report the case of a thirteen year old girl who underwent posterior instrumentation for correction of an idiopathic scoliosis. Intra-operatively there was a significant reduction in the amplitude of the MEPs without any corresponding change in the SEPs. These changes reversed when the correction was released. The surgery was abandoned and was carried out as a staged procedure, initially anteriorly then posteriorly. There was no loss of motor potentials during either operation and no post operative neurological abnormalities. We propose that the changes noted initially were due to transient ischaemia of the cord which would not have been detected without MEPs and may have led to long term sequelae. This highlights the safety benefit of routinely using MEPs in scoliosis surgery. Nationally there is wide variation in the monitoring of spinal cord function during scoliosis surgery. We feel that monitoring of motor potentials is a vital component in ensuring scoliosis surgery is as safe as possible

Peripheral nerve injury is an uncommon but serious complication of hip surgery that can adversely affect the outcome. Several studies have described the use of electromyography and intra-operative sensory evoked potentials for early warning of nerve injury. We assessed the results of multimodal intra-operative monitoring during complex hip surgery. We retrospectively analysed data collected between 2001 and 2010 from 69 patients who underwent complex hip surgery by a single surgeon using multimodal intra-operative monitoring from a total pool of 7894 patients who underwent hip surgery during this period. In 24 (35%) procedures the surgeon was alerted to a possible lesion to the sciatic and/or femoral nerve. Alerts were observed most frequently during peri-acetabular osteotomy. The surgeon adapted his approach based on interpretation of the neurophysiological changes. From 69 monitored surgical procedures, there was only one true positive case of post-operative nerve injury. There were no false positives or false negatives, and the remaining 68 cases were all true negative. The sensitivity for predicting post-operative nerve injury was 100% and the specificity 100%. We conclude that it is possible and appropriate to use this method during complex hip surgery and it is effective for alerting the surgeon to the possibility of nerve injury.