[Show abstract][Hide abstract] ABSTRACT: Background:
School screening programs for adolescent idiopathic scoliosis (AIS) have been discontinued in Canada and elsewhere because they were not considered cost-effective. In communities lacking such programs, we expect a significant variety of healthcare pathways and timeframes for patient referrals to orthopaedics. The objectives of this study were: 1) to characterise the healthcare pathways of young children with suspected AIS in a population without school screening; and 2) to investigate the relationships between these healthcare pathways and the appropriateness of referrals to specialised orthopaedic clinics.
This study concerned all children, ages 10 to 18, referred for an initial visit for suspected AIS to any of the five out-patient paediatric orthopaedic clinics of south-western Quebec (Canada). For the 831 participants, referrals to orthopaedics were characterised as appropriate, late, or inappropriate, based on known risk factors for AIS progression and on treatment indications. Parents documented the circumstances of healthcare use prior to the orthopaedic consultation. Relevant predisposing, enabling, and need variables derived from Andersen's Behavioral Model of Health Services Use were also documented. Healthcare pathways were characterised by developing a taxonomy using multiple correspondence analysis prior to hierarchical classification. Associations between the healthcare pathways and appropriateness of referral were assessed using multinomial regression analyses.
We constructed a taxonomy of five distinct healthcare pathways: 1) Lay/regular source of care interrelation, 2) Other professionals, 3) Lay/consultation discontinuity, 4) Other medical doctor, and 5) Regular source of care continuity. Laypersons played an important role in AIS suspicion (53 % of cases), but did not prevent late referrals. Continuity of care, as opposed to numerous uncoordinated consultations, was an effective strategy to prevent late referrals (OR = 0.32 [0.17-0.59]), but was related to increased probability of inappropriate referrals.
We identified two cardinal characteristics that distinguished the healthcare pathways and related significantly to appropriateness of referral status, namely the role of laypersons and the involvement of the regular source of care. This suggests directions for intervention such as advocating for access to a regular source of care, increasing awareness of the disease to medical practitioners' and improving their knowledge of AIS detection and referral criteria.
BMC Health Services Research 11/2015; 15(1):500. DOI:10.1186/s12913-015-1152-1 · 1.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Study Design: Retrospective study of surgical outcome.
Objectives: To evaluate quantitatively the changes in trunk surface deformities after scoliosis spinal surgery in Lenke 1A adolescent idiopathic scoliosis (AIS) patients and to compare it with changes in spinal measurements.
Summary of Background Data: Most studies documenting scoliosis surgical outcome used either radiographs to evaluate changes in the spinal curve or questionnaires to assess patients health-related quality of life. Because improving trunk appearance is a major reason for patients and their parents to seek treatment, this study focuses on postoperative changes in trunk surface deformities. Recently, a novel approach to quantify trunk deformities in a reliable, automatic, and noninvasive way has been proposed.
Methods: Forty-nine adolescents with Lenke 1A idiopathic scoliosis treated surgically were included. The back surface rotation and trunk lateral shift were computed on trunk surface acquisitions before and at least 6 months after surgery. We analyzed the effect of age, height, weight, curve severity, and flexibility before surgery, length of follow-up, and the surgical technique. For 25 patients with available three-dimensional (3D) spinal reconstructions, we compared changes in trunk deformities with changes in two-dimensional (2D) and 3D spinal measurements.
Results: The mean correction rates for the back surface rotation and the trunk lateral shift are 18% and 50%, respectively. Only the surgical technique had a significant effect on the correction rate of the back surface rotation. Direct vertebral derotation and reduction by spine translation provide a better correction of the rib hump (22% and 31% respectively) than the classic rod rotation technique (8%). The reductions of the lumbar Cobb angle and the apical vertebrae transverse rotation explain, respectively, up to 17% and 16% the reduction of the back surface rotation.
Conclusions: Current surgical techniques perform well in realigning the trunk; however, the correction of the deformity in the transverse plane proves to be more challenging. More analysis on the positive effect of vertebral derotation on the rib hump correction is needed.
[Show abstract][Hide abstract] ABSTRACT: Scoliosis is a 3D deformation of the spine and rib cage. For severe cases, surgery with spine instrumentation is required to restore a balanced spine curvature. This surgical procedure may represent a neurological risk for the patient, especially during corrective maneuvers. This study aimed to computationally simulate the surgical instrumentation maneuvers on a patient-specific biomechanical model of the spine and spinal cord to assess and predict potential damage to the spinal cord and spinal nerves. A detailed finite element model (FEM) of the spine and spinal cord of a healthy subject was used as reference geometry. The FEM was personalized to the geometry of the patient using a 3D biplanar radiographic reconstruction technique and 3D dual kriging. Step by step surgical instrumentation maneuvers were simulated in order to assess the neurological risk associated to each maneuver. The surgical simulation methodology implemented was divided into two parts. First, a global multi-body simulation was used to extract the 3D displacement of six vertebral landmarks, which were then introduced as boundary conditions into the personalized FEM in order to reproduce the surgical procedure. The results of the FEM simulation for two cases were compared to published values on spinal cord neurological functional threshold. The efficiency of the reported method was checked considering one patient with neurological complications detected during surgery and one control patient. This comparison study showed that the patient-specific hybrid model reproduced successfully the biomechanics of neurological injury during scoliosis correction maneuvers.
Computer Methods in Biomechanics and Biomedical Engineering 09/2015; DOI:10.1080/10255842.2015.1075010 · 1.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The clinical advantages of reducing spondylolisthesis over fusion in situ have several intuitive reasons such as restore the spinal column into a more anatomic relationship and alignment. However, there is only little evidence in the literature supporting the theoretical advantages of reduction, and its effect on spinopelvic alignment remains poorly defined. In this study, a comprehensive finite element model was developed to analyze the biomechanics of the spine after spinal fusion at L5-S1 in both types of high-grade spondylolisthesis (balanced and unbalanced pelvis). The relevant clinical indices (i.e. spondylolisthesis grade and Dubousset lumbosacral angle), the displacement of L4-L5, pressure within the annulus and nucleus, and stress at L4-L5 were evaluated and compared. The model can well predict the changes of the important clinical indices during the surgery. For a balanced pelvis, the reduction has a minimal effect on the biomechanical conditions at the adjacent level during postsurgical activities. In the unbalanced case, reduction induced larger deformation in the lumbosacral region and a higher stress concentration at adjacent level. Whether such a stress concentration can lead to long-term disc degeneration is not known. The results provide additional information for the clinician considering reduction of high-grade spondylolisthesis.
Medical & Biological Engineering 08/2015; DOI:10.1007/s11517-015-1353-0 · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Background: Back pain has often been associated with adolescent idiopathic scoliosis (AIS), which is a three-dimensional deviation of the vertebral column. In adolescents, chronic pain appears to be a predictor of health care utilization and has a negative impact on physical, psychological and family well-being. Back pain in this population tends to be persistent and may be a predictor of back pain in adulthood.
Objective: To document the prevalence and management of back pain (BP) in AIS patients.
Methods: We conducted a retrospective chart review of AIS patients who were referred to Sainte-Justine University Teaching Hospital from 2006 to 2011.
Results: We reviewed 300 randomly selected charts. Close to half the patients (47.3%) mentioned that they suffered back pain, most commonly in the lumbar (19.7%) and thoracic regions (7.7%). The type of back pain was documented in only 36% (112) of the charts. Pain intensity was specified in only 21% (65) of the charts. In approximately 80% (248) of the charts, no pain management treatment plan was documented.
Conclusions: Back pain prevalence was moderately high among our sample of adolescents with AIS. An improved system for documenting BP assessment, type, treatment plan and treatment effectiveness would improve pain management for these patients.
Pain research & management: the journal of the Canadian Pain Society = journal de la societe canadienne pour le traitement de la douleur 04/2015; · 1.52 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A biomechanical spine model was used to evaluate the impact of screw design on screw–vertebra interface loading during simulated surgical corrections of adult scoliosis.
[Show abstract][Hide abstract] ABSTRACT: Introduction: The quantification of internal joint efforts could be essential in the development of rehabilitation tools for patients with musculo-skeletal pathologies, such as scoliosis. In this context, the aim of this study was to compare the hips joint mediolateral forces during gait, between healthy subjects and adolescents with left lumbar or thoracolumbar scoliosis (AIS), categorized by their Cobb angle (CA).
Material and methods: Twelve healthy subjects, 12 AIS with CA between 20° and 40° and 16 AIS in pre-operative condition (CA : > 40°) walked at 4 km/h on an instrumented treadmill. The experimental set-up include six infrared cameras allow the computation of the tridimensional (3D) angular displacement and strain gauges located under the motor-driven treadmill allow the computation of ground reaction forces (GRF). The hips joint mediolateral forces were calculated using a 3D inverse dynamic of human body. One-way ANOVA was performed for the maximum, the minimum and the range of medio-lateral forces at each joint of the lower limbs. When appropriate, a Tukey’s post hoc was performed to determine the differences.
Results: The mediolateral forces were significantly lower at the right hip for AIS with CA between 20° and 40°
compared to healthy subject.
Conclusion: The spinal deformation leads to a reduced medio-lateral force at the right hip, which could gradually change the scheme of postural adjustments for AIS during gait. Further research on the quantification of the joint lower limb efforts should include the knee and ankle joints to evaluate the impact of spinal deformation on the lower limb dynamic behaviour in AIS patients.
[Show abstract][Hide abstract] ABSTRACT: Study Design. A replication association study that used genomic data generated from French-Canadian case and control cohorts.Objectives. To determine whether the 53 single nucleotide polymorphisms (SNPs) that were previously associated with spinal deformity progression in an American Caucasian cohort, are similarly associated in French-Canadian population.Summary of Background Data. It is widely accepted that genetic factors contribute to AIS. The identification of genetic variants associated with the predisposition or progression of curvature could facilitate diagnostic/prognostic tool development. Although 53 SNPs have been associated with spinal curve progression in Caucasian cohorts in the USA, these associations were not replicated in a large Japanese-population study, arguing that such a discrepancy could be explained by ethnicity, thus raising the importance of a replication study in an independent Caucasian population of European descent.Methods. Genomic data was collected from the French-Canadian population, using the Illumina HumanOmni 2.5M BeadChip. Fifty-two SNPs, tested in ScoliScore or in high linkage disequilibrium (LD) with SNPs in the test, were selected to assess their association with scoliosis generally, and with spinal curve progression. One SNP in ScoliScore, rs16909285, could not be evaluated in our GWAS.Results. None of the SNPs used in ScoliScore were associated with AIS curve progression or curve occurrence in French-Canadian population. We evaluated 52 SNPs in severe patients by comparing risk allele frequencies with those in non-severe patients and with those in control individuals. There was no significant difference between the severe group and the non-severe group or between the severe group and the control group.Conclusions. Although the 52 SNPs studied here were previously associated with curve progression in an American population of European descent, we found no association in French-Canadian AIS patients. This second replication cohort suggests that the lack of association of these SNPs in a Japanese cohort is not due to ethnicity.
[Show abstract][Hide abstract] ABSTRACT: Study Design. Retrospective review of prospective multicenter database of adolescent idiopathic scoliosis (AIS) patients who underwent posterior spinal fusion.Objective. To analyze implant distribution in surgically instrumented Lenke 1 patients and evaluate how it impacts curve correction.Summary of Background Data. While pedicle screw constructs have demonstrated successful surgical results, the optimal pedicle screw density and configuration remain unclear.Methods. 279 AIS patients treated with pedicle screws were reviewed. Implant density was computed for each side of the instrumented segment, which was divided into five regions: distal and proximal ends (upper/lower instrumented vertebra +1 adjacent vertebra), apical region (apex +/-1 vertebra) and the two regions in between (upper/lower periapical). Centralized measurement of Cobb angle and thoracic kyphosis was performed on pre-operative and at one-year post-operative radiographs as well as percent curve flexibility.Results. The mean implant density was 1.66 implants per level fused (1.08 to 2) with greater available pedicles filled on the concavity (92%, 53 to 100%) compared to the convex side (73%, 23 to 100%, p<0.01). The concave distal end region had the highest density with 99% of pedicles filled (p<0.01), followed by the other concave regions and the convex distal end region (88 to 94%) (p>0.05). Other convex regions of the construct had less instrumentation with only 54 to 78% of pedicles instrumented (p<0.01). Implant density in the concave apical region (p = 0.002, R = 0.19) had a positive effect on curve correction (69%, 23 to 100%).Conclusions. Significant variability exists in implant distribution with the greatest variation on the convex side and lowest implant density used in the periapical convex regions. Only instrumentation at the concave side, particularly at the apical region, was associated with curve correction. This suggests that for a low implant density construct the best regions for planned screw drop may be in the periapical convexity.
[Show abstract][Hide abstract] ABSTRACT: Background Variability in surgical strategies for the treatment of adolescent idiopathic scoliosis (AIS) has been demonstrated despite the existence of classifications to guide selection of AIS curves to include in fusion. Decision trees and rule-based algorithms have demonstrated their potential to improve reliability of AIS classification because of their systematic approach and they have also been proposed in algorithms for selection of instrumentation levels in scoliosis. Our working hypothesis is that a rule-based algorithm with a knowledge base extracted from the literature can efficiently output surgical strategies alternatives for a given AIS case. Our objective is to develop a rule-based algorithm based on peer-reviewed literature to output alternative surgical strategies for approach and levels of fusion. Methods A literature search of all English Manuscripts published between 2000 and December 2009 with Pubmed and Google scholar electronic search using the following keywords: “adolescent idiopathic scoliosis” and “surgery” alternatively with “levels of fusion” or “approach”. All returned abstracts were screened for contents that could contain rules to include in the knowledge base. A dataset of 1,556 AIS cases treated surgically was used to test the surgical strategy rule-based algorithm (SSRBA) and evaluate how many surgical treatments are covered by the algorithm. The SSRBA was programmed using Matlab. Descriptive statistic was used to evaluate the ability of the rule-based algorithm to cover all treatment alternatives. Results A SSRBA was successfully developed following Lenke classification’s concept that the spine is divided into three curve segments [proximal thoracic (PT), main thoracic (MT) and thoracolumbar/lumbar (TL)]. Each of the 1,556 AIS patients in the dataset was ran through the SSRBA. It proposed an average of 3.78 (±2.06) surgical strategies per case. Overall, the SSRBA is able to match the treatment offered by the surgeon in approach and level of fusion 70 % of the time (with one vertebral level leeway). Conclusion This study is to the author’s knowledge the first attempt at proposing an algorithm to output all surgical alternatives for a given AIS case. It uses a rule-based algorithm with a knowledge base extracted from peer-reviewed literature in an area with great variability. When tested against a database of AIS patients treated surgically, the SSRBA developed has the ability to propose a surgical plan with respect to approach and levels of fusion that match the surgeon’s plan in a great majority of cases. Since this SSRBA seems to output multiple valid surgical strategies, it could allow the comparisons of various strategies and the outcomes achieved in similar cases in large databases for a given case and guide surgical treatment.
European Spine Journal 01/2015; 24(7). DOI:10.1007/s00586-014-3736-6 · 2.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aim: Primary care practitioners should screen young adolescent patients for idiopathic scoliosis and refer those who could benefit from bracing to prevent curve progression and the need for surgery. Adolescents without a regular source of primary care may be at higher risk for not having their scoliosis diagnosed in time to benefit from bracing. We sought to determine whether adolescents with idiopathic scoliosis and a regular source of primary care are at lower risk of scoliosis surgery.