Stefan Parent

Stefan Parent
Université de Montréal | UdeM · Department of Surgery

MD, PhD

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388
Publications
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Publications

Publications (388)
Article
Purpose: Vertebral body tethering (VBT) has been described for patients with idiopathic scoliosis. Results of the technique for non-idiopathic scoliosis have not yet been reported. Methods: An international multicenter registry was retrospectively queried for non-idiopathic scoliosis patients who underwent VBT with minimum 2-year follow-up. Succ...
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PurposeTo assess the reliability of vertebral height and angular measurements for anterior vertebral body tethering (AVBT).Methods Eight observers measured PA radiographs of 15 idiopathic scoliosis patients treated with AVBT, pre-operative and 4-year follow-up. Vertebral wedging, disc wedging, convex vertebral body heights, and concave vertebral bo...
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Full-text available
PurposeThe HRQoL after surgery for adolescent idiopathic scoliosis (AIS) is not affected by the presence of concomitant isthmic spondylolisthesis non-surgically treated. Improvement in QoL after surgery was similar for AIS patients with and without concomitant spondylolisthesis. The purpose is to compare preoperative and postoperative Health-Relate...
Article
Traditionally, 2-year follow-up data have been the established standard for reporting clinical outcomes following spinal deformity surgery. However, previous studies indicate that 2-year follow-up does not represent long-term outcomes. Currently, there is no clear data that demonstrate a difference in outcomes between the 1 and 2 years postoperativ...
Article
Background: Growth modulation through anterior vertebral body tethering (AVBT) has emerged as a fusionless option for the treatment of progressive scoliosis. When tethering the main thoracic curve, the compensatory thoracolumbar/lumbar curve must correct indirectly as a result. The present study evaluated the response of these lumbar curves follow...
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Study Design Observational Cohort study. Objectives We aim to document the abandon and irregular compliance rate towards brace treatment during the COVID-19 pandemic and its impact on AIS progression. Methods We reviewed a database of AIS patients recruited between March and September 2020. We included AIS patients under brace treatment according...
Article
Given the challenges associated with managing progressive scoliosis in patients with cerebral palsy (CP), the purpose of this study was to evaluate deformity correction and HRQOL 5 years post-spinal fusion in CP patients who were skeletally immature at the time of surgical correction. CP patients who underwent definitive fusion before age 11 with m...
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Introduction: Patients with surgically treated Lenke 5 curves require at least partial fusion of the lumbar spine. The implications of lumbar fusion remain unknown as long-term follow-up is sparse. Methods: A retrospective review of a prospectively collected registry of patients with Lenke 5 curves treated with spinal fusion was performed. Clini...
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Background: Accurate reporting of long-term complications of surgical treatment of adolescent idiopathic scoliosis (AIS) is critical, but incomplete. This study aimed to report on the rate of complications following surgical treatment of AIS among patients with at least 10 years of follow-up. Methods: This was a retrospective review of prospecti...
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Introduction: Self-image and body shape are important to adolescent idiopathic scoliosis (AIS) patients. The impact of scoliosis on anterior trunk shape has been incompletely studied. The Truncal Anterior Asymmetry Scoliosis Questionnaire (TAASQ) was developed to assess anterior truncal appearance concerns and mental preoccupation and behavioral mo...
Article
Purpose: Prior work identified optimal outcomes at 2 years following selective thoracic fusion (STF) for adolescent idiopathic scoliosis (AIS) but it is unclear whether these published predictors represent what is required to achieve an optimal outcome with further time and potential growth. The purpose of this study was to determine the preoperat...
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Purpose: The correction of double thoracic (Lenke 2) curves has been associated with higher rates of postoperative shoulder imbalance that may compromise long-term outcomes following spinal deformity correction. A number of methods have been proposed to mitigate this risk, though no accepted standard measurement exists. The purpose of this study i...
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Purpose: Vertebral body tethering (VBT) continues to grow in interest from both a patient and surgeon perspective for the treatment of scoliosis. However, the data are limited when it comes to surgeon selection of both procedure type and instrumented levels. This study sought to assess surgeon variability in treatment recommendation and level sele...
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Study design: Observational cohort study. Objective: To test the hypothesis that anterior vertebral body growth modulation (AVBGM) achieves 3D deformity correction after 2-year follow-up while brace treatment limits curve progression for moderate idiopathic scoliosis (30-50°). Summary of background data: For idiopathic scoliosis, bracing and A...
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PurposeTo compare the outcomes of anterior Vertebral Body Tethering (AVBT) surgery between overweight and non-overweight patients.MethodsAIS/JIS patients with AVBT with 2-year follow-up from a multi-center pediatric spine database were evaluated pre-operatively, 1st post-operative erect, and 2 years post-operatively. ANOVA was used to compare 3 cat...
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Study design: Retrospective review of prospective data from multicenter registry. Objective: Compare outcomes of posterior spinal fusion (PSF) versus magnetically controlled growing rods (MCGR) versus vertebral body tethers (VBT) in 8- to 11-year-old idiopathic early onset scoliosis (EOS) patients. Summary of background data: In EOS, it is unc...
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Study design: Multicenter retrospective review. Objective: To calculate overall incidence of pedicle screw "plowing" in adolescent idiopathic scoliosis (AIS) patients who underwent posterior spinal fusion (PSF). To identify risk factors for pedicle screw plowing and associated postoperative outcomes, including loss of correction and revision rat...
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PurposeTypically, selection of lowest instrumented vertebra (LIV) in Adolescent Idiopathic Scoliosis (AIS) is based on the coronal radiograph; however, increasing evidence suggests that fusions proximal to the stable sagittal vertebrae (SSV) on the lateral radiograph can result in distal junctional kyphosis (DJK). The purpose of this study is to co...
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PurposeThe Clavien–Dindosink (CDS) classification system provides more treatment-focused granularity than subjective methods of describing surgical complications; however, it has not been validated in posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). The purpose of this study was to modify the CDS system for application in pa...
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Background: The use of vancomycin powder has been shown to decrease risk of surgical site infection (SSI) in early onset scoliosis (EOS). While there is potential benefit in SSI reduction, there is also theoretical risk in creating increased bacterial resistance to standard treatment regimens. However, the effects of topical vancomycin powder on m...
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PurposeIn adolescent idiopathic scoliosis (AIS), non-invasive surgical techniques such as anterior vertebral body tethering (AVBT) enable to treat patients with mild and severe degrees of deformity while maintaining lower lumbar motion by avoiding spinal fusion. However, multiple features and characteristics affect the overall patient outcome, nota...
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Adolescent idiopathic scoliosis (AIS) is a complex common disorder of multifactorial etiology defined by a deviation of the spine in three dimensions that affects approximately 2% to 4% of adolescents. Risk factors include other affected family members, suggesting a genetic component to the disease. The POC5 gene was identified as one of the first...
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Adolescent Idiopathic Scoliosis (AIS) is a deformation of the spine and it is routinely diagnosed using posteroanterior and lateral radiographs. The Risser sign used in skeletal maturity assessment is commonly accepted in AIS patient’s management. However, the Risser sign is subject to inter-observer variability and it relies mainly on the observat...
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PurposeTo report a case of iatrogenic durotomy with symptomatic Chiari-like deformity in a patient after undergoing anterior vertebral body growth modulation (AVBGM) in skeletally immature patients with adolescent idiopathic scoliosis (AIS). There have not been reports of iatrogenic durotomy in the literature and its management after AVBGM.MethodsA...
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Background Shoulder balance is an important factor for patient satisfaction following surgery for idiopathic scoliosis (IS). There is no literature reporting the effect of anterior vertebral body tethering (AVBT) on shoulder balance. The purpose of this study was to report the prevalence of postoperative shoulder imbalance in patients undergoing AV...
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Study Design: Prospective case series Objective: Determine the efficacy of anterior vertebral body tethering (AVBT) in skeletally immature patients Summary of Background Data: The value of AVBT is currently unclear given the paucity of available data. Methods: Consecutive skeletally immature patients with idiopathic scoliosis were treated with A...
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Study Design: Prospective case series Objective: Determine the efficacy of anterior vertebral body tethering (AVBT) in skeletally immature patients Summary of Background Data: The value of AVBT is currently unclear given the paucity of available data. Methods: Consecutive skeletally immature patients with idiopathic scoliosis were treated with AVBT...
Article
Managing patients with coronal imbalance (CI) and shoulder height asymmetry following scoliosis surgery can be challenging. Little is known about the course of findings over time and whether they improve or persist. The aim was to report the rate of suboptimal radiographic CI or shoulder asymmetry (SA) at 5 years in patients who were already report...
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PurposeBracing is the treatment of choice for idiopathic scoliosis (IS), unfortunately factors underlying brace response remain unknown. Clinicians are currently unable to identify patients who may benefit from bracing, and therefore, better molecular stratification is critically needed. The aim of this study is to evaluate IS patient outcomes at s...
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PurposeThe purpose of this study was to determine peri-operative morbidity associated with anterior vertebral body tethering (aVBT) for idiopathic scoliosis.Method Of 175 patients treated with aVBT, 120 patients had 2 year follow up and were included in this study. Prospectively collected clinical and radiographic data was analyzed retrospectively....
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Purpose Symptomatic adult spinal deformity (ASD) with an extremely variable presentation with pain, with and without neurogenic leg pain, and/or disturbed sagittal and coronal balance, causes a significant societal burden of disease. It is an important consequence of the aging adult population, generating a plethora of spine-related interventions w...
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Objective: Up to 50% of patients develop high-impact chronic pain after an acute care experience and many psychological variables have been identified in this process. We conducted a systematic review and meta-analysis of randomized controlled trials to assess the effect of psychological interventions within 3 months after pain onset. Methods: W...
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Aims To examine the efficacy of an immersive virtual reality distraction compared with an active non‐immersive distraction, such as video games on a tablet, for pain and anxiety management and memory of pain and anxiety in children requiring percutaneous bone pins and/or suture removal procedures. Design Three‐centre randomized clinical trial usin...
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Full-text available
Aims Spinal fusion remains the gold standard in the treatment of idiopathic scoliosis. However, anterior vertebral body tethering (AVBT) is gaining widespread interest, despite the limited data on its efficacy. The aim of our study was to determine the clinical efficacy of AVBT in skeletally immature patients with idiopathic scoliosis. Methods All...
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Study design: Longitudinal. Objectives: To evaluate whether the rate of patients who report low health related quality of life (HRQOL) scores at 2 years following surgical correction of adolescent idiopathic scoliosis (AIS) improves by 5 years postoperatively. Summary of background data: HRQOL scores are dependent upon a number of factors and...
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Recent fusionless surgical techniques for corrective spine surgery such as Anterior Vertebral Body Growth Modulation (AVBGM) allow to treat mild to severe spinal deformations by tethering vertebral bodies together, helping to preserve lower back flexibility. Forecasting the outcome of AVBGM from skeletally immature patients remains elusive with sev...
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Vertebral Body Growth Modulation (VBGM) allows to treat mild to severe spinal deformations by tethering vertebral bodies together, helping to preserve lower back flexibility. Forecasting the outcome of VBGM from skeletally immature patients remains elusive with several factors involved in corrective vertebral tethering, but could help orthopaedic s...
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Study design: Single-center prospective randomized controlled trial. Objective: To assess the computer-aided design/manufacturing (CAD/CAM) brace design approach, with and without added finite element modeling (FEM) simulations, after two years in terms of clinical outcomes, 3D correction, compliance and quality of life (QoL). Summary of backgr...
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BACKGROUND CONTEXT The Minimize Implants Maximize Outcomes (MIMO) Clinical Trial randomized patients with Lenke 1A curve patterns to more versus fewer screws (high or low density) to determine a difference in percent coronal correction. Last year we presented the intention to treat (IT) analysis, and this report covers the as treated analysis (AT)...
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BACKGROUND CONTEXT Although short-term adult symptomatic lumbar scoliosis (ASLS) outcomes studies favor operative over nonoperative treatment, long-term outcomes are critical for assessment of treatment durability. PURPOSE To assess whether operative treatment for ASLS provides greater improvement of patient-reported outcomes measures than nonoper...
Article
The management of idiopathic scoliosis in the skeletally immature patient can be challenging. Posterior spinal fusion and instrumentation is indicated for severe scoliosis deformities. However, the skeletally immature patient undergoing posterior fusion and instrumentation is at risk for developing crankshaft deformities. Moreover, bracing treatmen...
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Purpose: To develop an automatic method for the assessment of the Risser stage using deep learning that could be used in the management panel of adolescent idiopathic scoliosis (AIS). Materials and methods: In this institutional review board approved-study, a total of 1830 posteroanterior radiographs of patients with AIS (age range, 10-18 years,...
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Study designRetrospective reviewObjectives To report the frequency of pretreatment magnetic resonance imaging (MRI) utilization and rates and types of intra-spinal abnormalities identified on MRI in patients with early-onset scoliosis (EOS).Summary of background dataMRI can help identify spinal cord abnormalities in patients with EOS.Methods We rev...
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Study design: Numerical planning and simulation of immediate and after 2 years growth modulation effects of anterior vertebral body growth modulation (AVBGM). Objective: The objective was to evaluate the planning tool predictive capability for immediate, 1-year, and 2-year postoperative correction and biomechanical effect on growth modulation ov...
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Study design: Experimental biomechanical study of pressures exerted on the epiphyseal growth plates (GP) in tethered porcine cadaveric spines. Objectives: To experimentally measure the pressure exerted on the vertebral end plates of a tethered porcine spine model. Flexible spine tethering is a novel fusionless surgical technique that aims to cor...
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Study designRetrospective analysis of consecutive cases.Objectives To identify clinically relevant three-dimensional (3D) sub-groups for adolescent idiopathic scoliosis (AIS).Summary of background dataClassifications for AIS are developed to assist surgeons in surgical planning and therapeutic management. However, current systems are based on two-d...
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Study designExperimental in vivo study of the pressure exerted on the spine of a pig by a new cyclic anterior vertebral body tethering (AVBT) prototype.Objectives To evaluate the relationship between the tether tension and the pressures transmitted onto the vertebral end plates by a cyclic AVBT prototype.Summary of background dataAVBT is a recent s...
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Our objectives were to describe fetal cases of vertebral defects (VD), assess the diagnostic yield of fetal chromosomal analysis for VD and determine which investigations should be performed when evaluating fetal VD. We performed a retrospective chart review for fetuses with VD seen between 2006 and 2015. Cases were identified from CHU Sainte‐Justi...
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Study design: Prospective cohort study. Objective: The objective of the present study was to design a model of AIS progression to predict Cobb angle at full skeletal maturity, based on curve type, skeletal maturation, and 3D spine parameters available at first visit. Summary of background data: Adolescent idiopathic scoliosis (AIS) is a three-...
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Study Design: Literature Review Background: This white paper reviews the early reported outcomes of anterior vertebral body tethering (AVBT) and provides a brief update on the recent changes in regulatory status. Growth modulation by AVBT has the potential to transform scoliosis treatment in children and adolescents by reducing spinal curvature wit...
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Purpose Although surgical reduction in high-grade lumbosacral spondylolisthesis is often performed in young patients, criteria for defining adequate reduction leading to optimal outcomes have yet to be defined. The purpose of this study is to determine if surgical reduction in pelvic balance, slip grade, lumbosacral angle and L5 incidence are assoc...
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Purpose To investigate the effectiveness of surgical reduction in high-grade spondylolisthesis in maintaining or restoring a normal pelvic balance, as related to the QoL. Methods It is a retrospective analysis of prospectively collected data of 60 patients (17 males, 43 females) aged 15 ± 3.1 years who underwent surgery for high-grade spondylolist...
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BACKGROUND CONTEXT The role of implant density (anchors per level fused) has not been prospectively studied for a large cohort of AIS patients. In the Minimize Implants Maximize Outcomes (MIMO) Clinical Trial of equivalence, patients with Lenke 1A curve patterns were randomized to more versus fewer screws (high or low density) to determine if there...
Article
Objective: To determine the hemodynamic conditions associated with optimal neurologic improvement in individuals with acute traumatic spinal cord injury (SCI) who had lumbar intrathecal catheters placed to measure CSF pressure (CSFP). Methods: Ninety-two individuals with acute SCI were enrolled in this multicenter prospective observational clini...
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Study design: A retrospective analysis of a prospectively collected database was performed. Objective: The purpose of this study is to compare 3-dimensional correction associated with the anterior release (AR) and contemporary posterior instrumentation versus posterior-only surgery. Summary of background data: The role of AR as a tool in the t...
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Adolescent idiopathic scoliosis is the most prevalent spine deformity and the molecular mechanisms underlying its pathophysiology remain poorly understood. We have previously found a differential impairment of melatonin receptor signaling in AIS osteoblasts allowing the classification of patients into three biological endophenotypes or functional g...
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Introduction: It is unclear what factors influence health-related quality of life (HRQOL) in neuromuscular scoliosis. The aim of this study was to evaluate which factors are associated with an improvement in an HRQOL after spinal fusion surgery for nonambulatory patients with cerebral palsy (CP). Methods: A total of 157 patients with nonambulato...
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Purpose The objective of this study is to determine whether routine follow-up 5 years after adolescent idiopathic scoliosis (AIS) surgery is likely to affect postoperative care for patients treated with high-density pedicle screw constructs, when routine 2-year follow-up has been performed. Methods We reviewed 80 patients undergoing surgery for AI...
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Purpose The aim of this study was to evaluate the factors associated with timing of lowest hemoglobin (Hb) level and the need for postoperative blood transfusion in posterior spinal fusion for adolescent idiopathic scoliosis. Methods We conducted a retrospective review of all adolescent scoliosis patients undergoing posterior spinal fusion at our...
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Purpose Determining whether to fuse a Lenke 5 curve to L3 or to L4 is often a difficult decision. The purpose of this study was to determine preoperative variables predictive of an “ideal” or “less than ideal” outcome for Lenke 5 curves instrumented to L3. Methods A multicentre registry of adolescent idiopathic scoliosis patients was queried for s...
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Purpose: Image-guided spine surgery and preoperative computer-assisted planning provide spine surgeons with tools to improve the safety, accuracy and reliability of pedicle screw placement. The purpose of this study is to demonstrate a computer-assisted pedicle screw placement planning tool in comparison to screws as delivered by a spine surgeon....
Article
To date, 3D spine reconstruction from biplanar radiographs involves intensive user supervision and semiautomated methods that are time-consuming and not effective in clinical routine. This paper proposes a new, fast and automated 3D spine reconstruction method through which a realistic statistical shape model of the spine is fitted to images using...
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Full-text available
Adolescent Idiopathic Scoliosis (AIS) is a spinal deformity that affects approximately 3 percent of human adolescents. Although the etiology and molecular basis of AIS is unclear, several genes such as POC5 have been identified as possible causes of the condition. In order to understand the role of POC5 in the pathogenesis of AIS, we investigated t...