Identification of mechanism, PECARN risk factors and injury patterns in severe paediatric cervical spine injuries in Queensland

Introduction Canadian C spine rule and NEXUS criteria have identified risk factors for cervical spine injury in adults but not for children. PECARN has developed an 8 variable model for cervical spine injury in children. We sought to identify the mechanism, prevalence of PECARN risk factors, injury patterns, and management of severe Paediatric cervical spine injuries presenting to the major children’s hospitals in Brisbane, Australia. Methods This a retrospective study of the children with cervical spine injuries who presented directly or were referred to the major children’s hospitals in Brisbane over 5 years. Results There were 38 patients with 18 male and 20 female.The mean age was 8.6 years. They were divided into two groups according to their age, (Group 1 < =8 years had 18 (47%) patients, while group 2 (9-15 years) had 20 (53%) patients. Motor vehicle related injuries were the most common (61%) in Group 1 while it was sporting injuries (50%) in group 2. All patients in group 1 had upper cervical injury (C0-C2) while subaxial injuries were most common in group 2 (66.6%). 82% of the patients had 2 or more PECARN risk factors. 18 children (47%) had normal neurological assessment at presentation, 6 (16%) had radicular symptoms, 11 (29%) could not be assessed as they had already been intubated due to the severity of the injury, 3 (8%) had incomplete cord injury. 29 (69%) patients had normal neurological assessment at final follow up and 2 children died from their injuries. Conclusion Our study confirms that younger children sustain upper cervical injuries most commonly secondary to motor vehicle accidents, while the older sustain subaxial injuries from sporting activities. The significant prevalence of the PECARN risk factors among this cohort of patients have led to them being incorporated into a protocol at these hospitals used to assess patients with suspected cervical spinal injury

The vertebral body growth plate in scoliosis: a primary disturbance of growth?

Study Design and Aims: This was an observational pilot study of the vertebral body growth plates in scoliosis involving high-resolution coronal plane magnetic resonance (MR) imaging and histological examination. One aim of this study was to determine whether vertebral body growth plates in scoliosis demonstrated abnormalities on MR imaging. A second aim was to determine if a relationship existed between MR and histological abnormalities in these vertebral body growth plates. Methods: MR imaging sequences of 18 patients demonstrated the vertebralbody growth plates well enough to detect gross abnormalities/ deficient areas/zones. Histological examination of ten vertebral body growth plates removed during routine scoliosis surgery was performed. Observational histological comparison with MR images was possible in four cases. Results: Four of the 18 MR images demonstrated spines with normal curvature and normal vertebral body growth plates. In 13 scoliotic spines, convex and concave side growth plate deficiencies were observed most frequently at or near the apex of the curve. One MR image demonstrated a 55° kyphosis and no convex or concave side deficiencies. The degree of vertebral body wedging was independent of the presence of vertebral body growth plate deficiency. Histological abnormalities of the vertebral body growth plates were demonstrated in four with MR imaging abnormalities. Conclusion: This study demonstrated MR image abnormalities of scoliotic vertebral body growth plates compared to controls. A qualitative relationship was demonstrated between MR imaging and histological abnormalities. The finding that vertebral body growth plate deficiencies occurred both on the convex and concave sides of the spine, closest to the apical vertebra of the scoliosis curve, implied that they are less likely to be the result of adaptive changes to the physical forces involved in the scoliotic deformity. One explanation is that they represent a primary disturbance of growth

Mechanical Complications during Endoscopic Scoliosis Surgery

MECHANICAL COMPLICATIONS DURING ENDOSCOPIC SCOLIOSIS SURGERY John R Crawford, MareeT Izatt, Clayton J Adam, Robert D Labrom, Geoffrey N Askin Paediatric Spine Research Group, Queensland University of Technology and Mater Health Services, Brisbane, Australia INTRODUCTION Endoscopic scoliosis surgery can be complicated by rod breakage. The aim of this study was to examine the effect of rod breakage on clinical outcome and to determine any predisposing factors. METHODS We studied 83 consecutive patients that had undergone endoscopic correction for scoliosis. Patients were assessed pre-operatively and at regular intervals for up to three years post-operatively. Those patients sustaining rod breakages were compared with those that did not. Clinical outcome was assessed using the Scoliosis Research Society outcome instrument (SRS-24). Radiological assessment included coronal Cobb angles and the angle between adjacent screws. RESULTS There were 13 (15.7%) patients sustaining 16 rod breaks at a mean time from operation of 21.5 months. No significant change in Cobb angle occurred after rod breakage (mean 18.3 vs 19.7 degrees), p>0.05. Comparing patients with and without rod breaks we found no difference in SRS-24 scores for pain (4.30 vs 4.39), self image (3.50 vs 3.70), function (3.56 vs 3.35) or patient satisfaction (4.22 vs 4.58). There was no significant difference in screw angle for those patients that developed rod breakages (mean 3.2 vs 2.7 degrees). Significantly more breakages occurred with rib (11/40) and iliac crest (2/7) autograft compared with femoral allograft (0/36), p<0.01. DISCUSSION Rod breakage can occur following endoscopic scoliosis surgery. Our study shows that this is not associated with any significant loss of curve correction and has no effect on clinical outcome. Since changing to femoral allograft and by increasing the rod diameter no further rod breakages have occurred

Relationship between Curve Correction and Clinical Outcomes in Endoscopic Scoliosis Surgery

RELATIONSHIP BETWEEN CURVE CORRECTION AND CLINICAL OUTCOMES IN ENDOSCOPIC SCOLIOSIS SURGERY John R Crawford, Maree T Izatt, Clayton J Adam, Robert D Labrom, Geoffrey N Askin Paediatric Spine Research Group, Queensland University of Technology and Mater Health Services, Brisbane, Australia INTRODUCTION Radiographic parameters have been shown to have a poor correlation with clinical outcome after open scoliosis procedures. However this has not been previously addressed after endoscopic surgery. The purpose of our study was to prospectively examine the relationship between curve correction and clinical outcome for endoscopic scoliosis surgery. METHODS We studied 50 consecutive patients that underwent endoscopic instrumentation, with a minimum follow-up of two years. All patients were assessed pre-operatively and at 24 months post-operatively. Radiological parameters were measured from plain standing radiographs including the coronal Cobb angle, sagittal alignment, coronal alignment and shoulder elevation. Clinical outcome was assessed using the Scoliosis Research Society Outcomes Instrument (SRS-24). Correlation between radiological parameters and SRS-24 scores were determined using the Pearson correlation coefficient. RESULTS There were 45 females and 5 males with a mean age of 16.4 years (range, 10 to 46). The pre-operative coronal Cobb angle was mean 51.7 ± 8.5 and the post-operative instrumented Cobb angle was mean 20.4 ± 7.8 corresponding to a mean curve correction of 60.7%. There was a positive correlation between instrumented Cobb angle and total SRS-24 score (p=0.03, r2=0.085) and between curve correction and total SRS-24 score (p=0.04, r2=0.081). No correlation was found between coronal alignment, sagittal alignment, shoulder elevation or size of rib hump and the SRS-24 scores (p>0.05). DISCUSSION Overall endoscopic scoliosis surgery was associated with a good clinical outcome for our series of patients. Using a validated assessment instrument, clinical outcome correlated well with the amount of curve correction achieved

Quantifying Typical Progression of Adolescent Idiopathic Scoliosis: Longitudinal Three-Dimensional MRI Measures of Disk and Vertebral Deformities

STUDY DESIGN: A prospective cohort study. OBJECTIVE: Detail typical three-dimensional segmental deformities and their rates of change that occur within developing adolescent idiopathic scoliosis (AIS) spines over multiple timepoints. SUMMARY OF BACKGROUND DATA: AIS is a potentially progressive deforming condition that occurs in three dimensions of the scoliotic spine during periods of growth. However, there remains a gap for multiple timepoint segmental deformity analysis in AIS cohorts during development. MATERIALS AND METHODS: Thirty-six female patients with Lenke 1 AIS curves underwent two to six sequential magnetic resonance images. Scans were reformatted to produce images in orthogonal dimensions. Wedging angles and rotatory values were measured for segmental elements within the major curve. Two-tailed, paired t tests compared morphologic differences between sequential scans. Rates of change were calculated for variables given the actual time between successive scans. Pearson correlation coefficients were determined for multidimensional deformity measurements. RESULTS: Vertebral bodies were typically coronally convexly wedged, locally lordotic, convexly axially rotated, and demonstrated evidence of local mechanical torsion. Between the first and final scans, apical measures of coronal wedging and axial rotation were all greater in both vertebral and intervertebral disk morphology than nonapical regions (all reaching differences where P <0.05). No measures of sagittal deformity demonstrated a statistically significant change between scans. Cross-planar correlations were predominantly apparent between coronal and axial planes, with sagittal plane parameters rarely correlating across dimensions. Rates of segmental deformity changes between earlier scans were characterized by coronal plane convex wedging and convexly directed axial rotation. The major locally lordotic deformity changes that did occur in the sagittal plane were static between scans. CONCLUSIONS: This novel investigation documented a three-dimensional characterization of segmental elements of the growing AIS spine and reported these changes across multiple timepoints. Segmental elements are typically deformed from initial presentation, and subsequent changes occur in separate orthogonal planes at unique times.</p

A Prospective Assessment of SRS-24 Scores after Endoscopic Anterior Instrumentration for Scoliosis

A PROSPECTIVE ASSESSMENT OF SRS-24 SCORES AFTER ENDOSCOPIC ANTERIOR INSTRUMENTATION FOR SCOLIOSIS John R Crawford, Maree T Izatt, Clayton J Adam, Robert D Labrom, Geoffrey N Askin Paediatric Spine Research Group, Queensland University of Technology and Mater Health Services, Brisbane, Australia INTRODUCTION Endoscopic instrumentation for scoliosis has several advantages compared with open procedures. The purpose of our study was to prospectively assess the clinical outcome of patients after endoscopic anterior instrumentation and to evaluate their responses over time. METHODS A total of 83 consecutive patients underwent endoscopic instrumentation performed at a single unit. Patients completed the SRS-24 Outcomes Instrument pre-operatively and at 3, 6, 12 and 24 months post-operatively. The seven domains of the SRS-24 score were compared between each of the follow-up intervals. The dataset contained 24 responses at 3 months, 65 responses at 6 months, 63 responses at 12 months and 49 responses at 24 months. RESULTS There were 74 females and nine males with a mean age of 16.4 years (range, 10 to 46 years). The mean Cobb angle improved from 52.8 degrees pre-operatively to 21.9 degrees post-operatively. Over the follow-up period there were significant improvements in the activity level (p<0.05), function from back condition (p<0.05) and post-operative function (p<0.01) domains. Most of this improvement occurred during the first post-operative year and none of the domains improved further after this time interval. There was no significant change in the pain, self image and patient satisfaction domains. DISCUSSION Our results for endoscopic scoliosis correction are comparable with those reported for open procedures. The greatest improvement in SRS scores occurred between six and twelve months post-operatively. The SRS-24 scores at one year from surgery may provide a good indicator of patient outcome in the long-term

Sequential MRI reveals vertebral body wedging significantly contributes to coronal plane deformity progression in adolescent idiopathic scoliosis during growth

Study design: Cross-sectional study. Objectives: To provide a comprehensive, multi-stage investigation of vertebral body (VB) and intervertebral disc (IVD) coronal plane deformities for adolescent idiopathic scoliosis (AIS) patients with a main thoracic curve type, using a series of sequential magnetic resonance images (MRIs). Summary of background data: Despite numerous investigations of AIS deformity at the spinal segmental level, there is little consensus as to the major contributor to the lateral curvature of a scoliotic spine. Moreover, scoliotic deformity is often described along a continuum of progression, with few studies having characterised the change in segmental deformity for AIS patients whose deformity progresses clinically over time. Methods: 30 female AIS patients with primary thoracic curves were included between 2012 and 2016. Three sequential MRIs were captured for each patient. Datasets were reformatted to produce true coronal plane images of the thoracic spine (T4–L1). Overall curve morphology, coronal plane IVD and VB segmental deformity and rates of growth were analysed. Results: Right-side asymmetry was greater in IVDs (18.5 ± 23.9%) when compared to VBs (8.3 ± 9.2%) (P 50%) of their coronal curvature was attributed to VB wedging when measured across all three scans. Regardless of progression status, scan number, or region, the sum of the VB wedging angle was greater than the sum of the IVD wedging angle (all P ≤ 0.05). There was no correlation between the rates of major curve angle progression and standing height increase, VB height growth, or IVD height growth (P > 0.05). Conclusions: VB wedging contributed more to the lateral deformity observed in primary thoracic subtypes of AIS patients than IVD wedging. While IVDs demonstrated the greatest asymmetric deformity, their relatively smaller height resulted in a smaller proportional change in lateral curve angle compared to the VBs. Level of evidence: IV

Adolescent idiopathic scoliosis 3D vertebral morphology, progression and nomenclature: a current concepts review

PURPOSE: There has been a recent shift toward the analysis of the pathoanatomical variation of the adolescent idiopathic scoliosis (AIS) spine with the three dimensions, and research of level-wise vertebral body morphology in single anatomical planes is now replete within the field. In addition to providing a precise description of the osseous structures that are the focus of instrumented surgical interventions, understanding the anatomical variation between vertebral bodies will elucidate possible pathoaetiological mechanisms of the onset of scoliotic deformity.METHODS: This review aimed to discuss the current landscape of AIS segmental vertebral morphology research and provide a comprehensive report of the typical patterns observed at the individual vertebral level.RESULTS: We have detailed how these vertebrae are typically characterised by lateral wedging to the convexity, have a marked degree of anterior overgrowth, are rotated towards the convexity, have inherent gyratory mechanical torsion created within them and are associated with pedicles on the concave side being narrower, longer and more laterally angled. For the most part, these findings are most pronounced at and around the apex of a scoliotic curve, with these deformations reducing towards junctional vertebrae. We have also summarised a nomenclature defined by the Scoliosis Research Society, highlighting the need for more consistent reporting of these level-wise dimensional anatomical changes.CONCLUSION: Finally, we emphasised how a marked degree of heterogeneity exists between the included investigations, namely in scoliotic curve-type inclusion, imaging modality and timepoint of analysis within scoliosis' longitudinal development, and how improvement in these study design characteristics will enhance ongoing research.</p

Longitudinal performance of polycaprolactone-based scaffold plus recombinant human morphogenetic protein-2 (rhBMP-2) in large preclinical animal model : 6- versus 12 months

There is strong current interest in the use of biodegradable scaffolds in combination with bone growth factors as a valuable alternative to the current gold standard autograft in spinal fusion surgery Yong et al. (2013). Here we report on 6- vs 12- month data set evaluating the longitudinal performance of a CaP coated polycaprolactone (PCL) scaffold loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute within a preclinical ovine thoracic spine. The results of this study demonstrate the efficacy of scaffold-based delivery of rhBMP-2 in promoting higher fusion grades at 6- and 12- months in comparison to the scaffold alone or autograft group within the same time frame. Fusion grades achieved at six months using PCL+rhBMP-2 are not significantly increased at twelve months post surgery

6 versus 12 month performance of polycaprolactone-based scaffold plus recombinant human morphogenetic protein-2 (rhBMP-2) in an ovine thoracic interbody fusion model

Introduction Well-designed biodegradable scaffolds in combination with bone growth factors offer a valuable alternative to the current gold standard autograft in spinal fusion surgery Yong et al. (2013). Here we report on 6- vs 12- month data set evaluating the longitudinal performance of a CaP coated polycaprolactone (PCL) scaffold loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute within a large preclinical animal model. Methods Twelve sheep underwent a 3-level (T6/7, T8/9 and T10/11) discectomy with randomly allocated implantation of a different graft substitute at each of the three levels; (i) calcium phosphate (CaP) coated polycaprolactone based scaffold plus 0.54µg rhBMP-2, (ii) CaP coated PCL- based scaffold alone or (iii) autograft (mulched rib head). Fusion assessments were performed via high resolution clinical computed tomography and histological evaluation were undertaken at six (n=6) and twelve (n=6) months post-surgery using the Sucato grading system (Sucato et al. 2004). Results The computed tomography fusion grades of the 6- and 12- months in the rhBMP-2 plus PCL- based scaffold group were 1.9 and 2.1 respectively, in the autograft group 1.9 and 1.3 respectively, and in the scaffold alone group 0.9 and 1.17 respectively. There were no statistically significant differences in the fusion scores between 6- and 12- month for the rhBMP plus PCL- based scaffold or PCL – based scaffold alone group however there was a significant reduction in scores in the autograft group. These scores were seen to correlate with histological evaluations of the respective groups. Conclusions The results of this study demonstrate the efficacy of scaffold-based delivery of rhBMP-2 in promoting higher fusion grades at 6- and 12- months in comparison to the scaffold alone or autograft group within the same time frame. Fusion grades achieved at six months using PCL+rhBMP-2 are not significantly increased at twelve months post-surgery