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Tognini M, Hothi H, Bergiers S, Broomfield E, Tucker S, Henckel J, Hart A. Rod Fracture in Magnetically Controlled Growing Spine Rods. J Pediatr Orthop 2023; 43:211-217. [PMID: 36737055 PMCID: PMC9981316 DOI: 10.1097/bpo.0000000000002361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The mechanisms of fracture in magnetically controlled growing rods (MCGRs) and the risk factors associated with this are poorly understood. This retrospective analysis of explanted MCGRs aimed to add understanding to this subject. METHODS From our cohort of over 120 retrieved MCGRs, we identified 7 rods that had fractured; all were single-rod constructs, retrieved from 6 patients. These were examined and compared with 15 intact single-rod constructs. Retrieval and fractographic analyses were used to determine the failure mode at the fracture site and the implant's functionality. Cobb angle, degree of rod contouring, and the distance between anchoring points were computed on anteroposterior and lateral radiographs. RESULTS 5/7 versus 3/15 rods had been inserted after the removal of a previously inserted rod, in the fractured versus control groups. All fractured rods failed due to bending fatigue. Fractured rods had greater rod contouring angles in the frontal plane ( P = 0.0407) and lateral plane ( P = 0.0306), and greater distances between anchoring points in both anteroposterior and lateral planes ( P = 0.0061 and P = 0.0074, respectively). CONCLUSIONS We found all failed due to a fatigue fracture and were virtually all single rod configurations. Fracture initiation points corresponded with mechanical indentation marks induced by the intraoperative rod contouring tool. Fractured rods had undergone greater rod contouring and had greater distances between anchoring points, suggesting that it is preferable to implant double rod constructs in patients with sufficient spinal maturity to avoid this complication. CLINICAL RELEVANCE Level III.
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Affiliation(s)
- Martina Tognini
- Royal National Orthopaedic Hospital and Institute of Orthopaedics and Musculoskeletal Science, University College London, Stanmore
| | - Harry Hothi
- Royal National Orthopaedic Hospital and Institute of Orthopaedics and Musculoskeletal Science, University College London, Stanmore
| | - Sean Bergiers
- Royal National Orthopaedic Hospital and Institute of Orthopaedics and Musculoskeletal Science, University College London, Stanmore
| | - Edel Broomfield
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Stewart Tucker
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Johann Henckel
- Royal National Orthopaedic Hospital and Institute of Orthopaedics and Musculoskeletal Science, University College London, Stanmore
| | - Alister Hart
- Royal National Orthopaedic Hospital and Institute of Orthopaedics and Musculoskeletal Science, University College London, Stanmore
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Pei B, Lu D, Wu X, Xu Y, Ma C, Wu S. Kinematic and biomechanical responses of the spine to distraction surgery in children with early onset scoliosis: A 3-D finite element analysis. Front Bioeng Biotechnol 2022; 10:933341. [PMID: 35910017 PMCID: PMC9336159 DOI: 10.3389/fbioe.2022.933341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Accepted: 06/27/2022] [Indexed: 12/02/2022] Open
Abstract
Periodical and consecutive distraction is an effective treatment for severe early onset scoliosis (EOS), which enables the spinal coronal and sagittal plane deformity correction. However, the rate of rod fractures and postoperative complications was still high mainly related to the distraction process. Previous studies have primarily investigated the maximum safe distraction force without a rod broken, neglecting the spinal re-imbalance and distraction energy consumption, which is equally vital to evaluate the operative value. This study aimed to reveal the kinematic and biomechanical responses occurring after spinal distraction surgery, which were affected by traditional bilateral fixation. The spinal models (C6-S1) before four distractions were reconstructed based on CT images and the growing rods were applied with the upward displacement load of 0–25 mm at an interval of 5 mm. Relationships between the distraction distance, the distraction force and the thoracic and lumbar Cobb angle were revealed, and the spinal displacement and rotation in three-dimensional directions were measured. The spinal overall imbalance would also happen during the distraction process even under the safe force, which was characterized by unexpected cervical lordosis and lateral displacement. Additionally, the law of diminishing return has been confirmed by comparing the distraction energy consumption in different distraction distances, which suggests that more attention paid to the spinal kinematic and biomechanical changes is better than to the distraction force. Notably, the selection of fixed segments significantly impacts the distraction force at the same distraction distance. Accordingly, some results could provide a better understanding of spinal distraction surgery.
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Affiliation(s)
- Baoqing Pei
- Beijing key laboratory for design and evaluation technology of advanced implantable and interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Da Lu
- Beijing key laboratory for design and evaluation technology of advanced implantable and interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Xueqing Wu
- Beijing key laboratory for design and evaluation technology of advanced implantable and interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
- *Correspondence: Xueqing Wu, ; Shuqin Wu,
| | - Yangyang Xu
- Beijing key laboratory for design and evaluation technology of advanced implantable and interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Chenghao Ma
- Beijing key laboratory for design and evaluation technology of advanced implantable and interventional medical devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Shuqin Wu
- School of Big Data and Information, Shanxi College of Technology, Shanxi, China
- *Correspondence: Xueqing Wu, ; Shuqin Wu,
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Finite Element Comparison of the Spring Distraction System and the Traditional Growing Rod for the Treatment of Early Onset Scoliosis. Spine (Phila Pa 1976) 2022; 47:E456-E465. [PMID: 34935758 DOI: 10.1097/brs.0000000000004297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Finite element analysis (FEA). OBJECTIVE The aim of this study was to determine biomechanical differences between traditional growing rod (TGR) and spring distraction system (SDS) treatment of early-onset scoliosis. SUMMARY OF BACKGROUND DATA Many "growth-friendly" implants like the TGR show high rates of implant failure, spinal stiffening, and intervertebral disc (IVD) height loss. We developed the SDS, which employs continuous, dynamic forces to mitigate these limitations. The present FEA compares TGR and SDS implantation, followed by an 18-month growth period. METHODS Two representative, ligamentous, scoliotic FEA models were created for this study; one representing TGR and one representing SDS. initial implantation, and up to 18 months of physeal spinal growth were simulated. The SDS model was continuously distracted over this period; the TGR model included two additional distractions following index surgery. Outcomes included differences in rod stress, spinal morphology and iVD stress-shielding. RESULTS Maximum postoperative von Mises stress was 249MPa for SDS, and 205MPa for TGR. During the 6-month TGR distraction, TGR rod stress increased over two-fold to a maximum stress of 417MPa, compared to a maximum of 262 MPa in the SDS model at 6-month follow-up. During subsequent follow-up periods, TGR rod stress remained consistently higher than stresses in the SDS model. Additional lengthenings in the TGR model led to a smaller residual curve (16.08) and higher T1-S1 growth (359 mm) at 18-month follow-up compared to the SDS model (26.98, 348 mm). During follow-up, there was less stress-shielding of the IVDs in the SDS model, compared to the TGR model. At 18-month follow-up, upper and lower IVD surfaces of the SDS model were loaded more in compression than their TGR counterparts (mean upper: +112 ± 19N; mean lower: +100 ± 17N). CONCLUSION In the present FEA, TGR treatment resulted in slightly larger curve correction compared to SDS, at the expense of increased IVD stress-shielding and a higher risk of rod fractures. LEVEL OF EVIDENCE N/A.
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Shekouhi N, Kelkar A, Dick D, Goel VK, Shaw D. Current benchtop protocols are not appropriate for the evaluation of distraction-based growing rods: a literature review to justify a new protocol and its development. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2022; 31:963-979. [PMID: 35092449 DOI: 10.1007/s00586-022-07113-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 12/05/2021] [Accepted: 01/07/2022] [Indexed: 01/29/2023]
Abstract
PURPOSE Although distraction-based growing rods (GR) are the gold standard for the treatment of early onset scoliosis, they suffer from high failure rates. We have (1) performed a literature search to understand the deficiencies of the current protocols, (2) in vitro evaluation of GRs using our proposed protocol and performed a finite element (FE) model validation, and (3) identified key features which should be considered in mechanical testing setups. METHODS PubMed, Embase, and Web of Science databases were searched for articles published on (a) in vivo animal, in vitro cadaveric, and biomechanical studies analyzing the use of GRs as well as (b) failure mechanisms and risk factors for GRs. Both FE and benchtop models of a proposed TGR test construct were developed and evaluated for two cases, long tandem connectors (LT), and side-by-side connectors (SBS). The test construct consisted of five polymer blocks representing vertebral bodies, joined with springs to simulate spinal stiffness. The superior and inferior blocks accepted the pedicle screw anchors, while the three middle blocks were floating. After the pedicle screws, rods, and connectors were assembled onto this construct, distraction was performed, mimicking scoliosis surgery. The resulting distracted constructs were then subjected to static compression-bending loading. Yield load and stiffness were calculated and used to verify/validate the FE results. RESULTS From the literature search, key features identified as significant were axial and transverse connectors, contoured rods, and distraction, distraction being the most challenging feature to incorporate in testing. The in silico analyses, once they are validated, can be used as a complementing technique to investigate other anatomical features which are not possible in the mechanical setup (like growth/scoliosis curvature). Based on our experiment, the LT constructs showed higher stiffness and yield load compared to SBS (78.85 N/mm vs. 59.68 N/mm and 838.84 N vs. 623.3 N). The FE predictions were in agreement with the experimental outcomes (within 10% difference). The maximum von Mises stresses were predicted adjacent to the distraction site, consistent with the location of observed failures in vivo. CONCLUSION The two-way approach presented in this study can lead to a robust prediction of the contributing factors to the in vivo failure.
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Affiliation(s)
- Niloufar Shekouhi
- Departments of Bioengineering and Orthopaedic Surgery, Engineering Center for Orthopedic Research Excellence (E-CORE), Colleges of Engineering and Medicine, University of Toledo, 2801 West Bancroft Street, MS 303, NI Hall, Room 5046, Toledo, OH, 43606, USA
| | - Amey Kelkar
- Departments of Bioengineering and Orthopaedic Surgery, Engineering Center for Orthopedic Research Excellence (E-CORE), Colleges of Engineering and Medicine, University of Toledo, 2801 West Bancroft Street, MS 303, NI Hall, Room 5046, Toledo, OH, 43606, USA
| | - David Dick
- Departments of Bioengineering and Orthopaedic Surgery, Engineering Center for Orthopedic Research Excellence (E-CORE), Colleges of Engineering and Medicine, University of Toledo, 2801 West Bancroft Street, MS 303, NI Hall, Room 5046, Toledo, OH, 43606, USA
| | - Vijay K Goel
- Departments of Bioengineering and Orthopaedic Surgery, Engineering Center for Orthopedic Research Excellence (E-CORE), Colleges of Engineering and Medicine, University of Toledo, 2801 West Bancroft Street, MS 303, NI Hall, Room 5046, Toledo, OH, 43606, USA.
| | - Derek Shaw
- DePuy Synthes Spine, 325 Paramount Drive, Raynham, MA, 02767, USA
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Pei B, Lu D, Wu X, Xu Y, Ma C, Wu S. Effects of Growing Rod Technique with Different Surgical Modes and Growth Phases on the Treatment Outcome of Early Onset Scoliosis: A 3-D Finite Element Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19042057. [PMID: 35206246 PMCID: PMC8872610 DOI: 10.3390/ijerph19042057] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 02/09/2022] [Accepted: 02/10/2022] [Indexed: 11/16/2022]
Abstract
Early onset scoliosis (EOS) is emerging as a serious threat to children’s health and is the third largest threat to their health after myopia and obesity. At present, the growing rod technique (GRT), which allows patients to regain a well-balanced sagittal profile, is commonly considered as an invasive surgical procedure for the treatment of EOS. However, the risk of postoperative complications and instrumentation breakage remains high, which is mainly related to the choice of fixed mode. Several authors have studied primary stability and instrumentation loads, neglecting the mechanical transmission of the spinal long-segment model in different growth phases, which is fundamental to building a complete biomechanical environment. The present study aimed to investigate the kinematic and biomechanical properties that occur after GRT, across the long spinal structure and the posterior instrumentation, which are affected by unilateral or bilateral fixation. Accordingly, spinal segments (C6-S1) were loaded under flexion (Flex), extension (Ext), left lateral bending (LB), right lateral bending (RB), left torsion (LT), and right torsion (RT) using 11 established spinal models, which were from three growth phases. The stress distribution, spinal and intervertebral range of motion (ROM), counter torque of the vertebra, and bracing force on the rods were measured. The results showed that bilateral posterior fixation (BPF) is more stable than unilateral posterior fixation (UPF), at the expense of more compensations for the superior adjacent segment (SAS), especially when the superior fixed segment is closer to the head. Additionally, the bracing force of the instrumentation on the spine increases as the Cobb angle decreases. Accordingly, this biomechanical analysis provides theoretical suggestions for the selection of BPF or UPF and fixed segments in different growing phases.
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Affiliation(s)
- Baoqing Pei
- Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China; (B.P.); (D.L.); (Y.X.); (C.M.)
| | - Da Lu
- Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China; (B.P.); (D.L.); (Y.X.); (C.M.)
| | - Xueqing Wu
- Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China; (B.P.); (D.L.); (Y.X.); (C.M.)
- Correspondence: (X.W.); (S.W.)
| | - Yangyang Xu
- Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China; (B.P.); (D.L.); (Y.X.); (C.M.)
| | - Chenghao Ma
- Beijing Key Laboratory for Design and Evaluation Technology of Advanced Implantable & Interventional Medical Devices, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China; (B.P.); (D.L.); (Y.X.); (C.M.)
| | - Shuqin Wu
- School of Big Data and Information, Shanxi College of Technology, Shuozhou 036000, China
- Correspondence: (X.W.); (S.W.)
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Gould SL, Cristofolini L, Davico G, Viceconti M. Computational modelling of the scoliotic spine: A literature review. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2021; 37:e3503. [PMID: 34114367 PMCID: PMC8518780 DOI: 10.1002/cnm.3503] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 05/26/2021] [Accepted: 06/04/2021] [Indexed: 06/12/2023]
Abstract
Scoliosis is a deformity of the spine that in severe cases requires surgical treatment. There is still disagreement among clinicians as to what the aim of such treatment is as well as the optimal surgical technique. Numerical models can aid clinical decision-making by estimating the outcome of a given surgical intervention. This paper provided some background information on the modelling of the healthy spine and a review of the literature on scoliotic spine models, their validation, and their application. An overview of the methods and techniques used to construct scoliotic finite element and multibody models was given as well as the boundary conditions used in the simulations. The current limitations of the models were discussed as well as how such limitations are addressed in non-scoliotic spine models. Finally, future directions for the numerical modelling of scoliosis were addressed.
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Affiliation(s)
- Samuele L. Gould
- Department of Industrial EngineeringAlma Mater Studiorum‐University of Bologna (IT)BolognaItaly
- Medical Technology LabIRCCS Istituto Ortopedico RizzoliBolognaItaly
| | - Luca Cristofolini
- Department of Industrial EngineeringAlma Mater Studiorum‐University of Bologna (IT)BolognaItaly
| | - Giorgio Davico
- Department of Industrial EngineeringAlma Mater Studiorum‐University of Bologna (IT)BolognaItaly
- Medical Technology LabIRCCS Istituto Ortopedico RizzoliBolognaItaly
| | - Marco Viceconti
- Department of Industrial EngineeringAlma Mater Studiorum‐University of Bologna (IT)BolognaItaly
- Medical Technology LabIRCCS Istituto Ortopedico RizzoliBolognaItaly
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Distraction forces on the spine in early-onset scoliosis: A systematic review and meta-analysis of clinical and biomechanical literature. J Biomech 2021; 124:110571. [PMID: 34174488 DOI: 10.1016/j.jbiomech.2021.110571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/02/2021] [Accepted: 06/07/2021] [Indexed: 11/21/2022]
Abstract
Distraction-based growing rods are frequently used to treat Early-Onset Scoliosis. These use intermittent spinal distractions to maintain correction and allow for growth. It is unknown how much spinal distraction can be applied safely. We performed a systematic review and meta-analysis of clinical and biomechanical literature to identify such safety limits for the pediatric spine. This systematic review and meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Three systematic searches were performed including in-vivo, ex-vivo and in-silico literature. Study quality was assessed in all studies and data including patient- or specimen characteristics, distraction magnitude and spinal failure location and ultimate force at failure were collected. Twelve studies were included, 6 in-vivo, 4 ex-vivo and 2 in-silico studies. Mean in-vivo distraction forces ranged between 242 and 621 N with maxima of 422-981 N, without structural failures when using pedicle screw constructs. In the ex-vivo studies (only cervical spines), segment C0-C2 was strongest, with decreasing strength in more distal segments. Meta-regression analysis demonstrated that ultimate force at birth is 300-350 N, which increases approximately 100 N each year until adulthood. Ex-vivo and in-silico studies showed that yielding occurs at 70-90% of ultimate force, failure starts at the junction between endplate and intervertebral disc, after which the posterior- and anterior long ligament rupture. While data on safety of distraction forces is limited, this systematic review and meta-analysis may aid in the development of guidelines on spinal distraction and may benefit the development and optimization of contemporary and future distraction-based technologies.
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Lemans JVC, Wijdicks SPJ, Castelein RM, Kruyt MC. Spring distraction system for dynamic growth guidance of early onset scoliosis: two-year prospective follow-up of 24 patients. Spine J 2021; 21:671-681. [PMID: 33221513 DOI: 10.1016/j.spinee.2020.11.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 11/06/2020] [Accepted: 11/14/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND Current surgical treatment options for early onset scoliosis (EOS), with distraction- or growth-guidance implants, show limited growth and high complication rates during follow-up. We developed a novel implant concept, which uses compressed helical springs positioned around the rods of a growth-guidance construct. This spring distraction system (SDS) provides continuous corrective force to stimulate spinal growth, can be easily contoured, and can be used with all standard spinal instrumentation systems. PURPOSE To assess curve correction and -maintenance, spinal growth, complication rate, and health-related quality of life following SDS treatment. STUDY DESIGN Prospective cohort study. PATIENT SAMPLE All skeletally immature EOS patients with an indication for growth-friendly surgery and without bone- or soft tissue weakness were eligible to receive SDS. For this study, all included patients with at least 2-year follow-up were analyzed. OUTCOME MEASURES Coronal Cobb angle, sagittal parameters, T1-T12, T1-S1, and instrumented (ie, bridged segment) spinal height and freehand length, complications and re-operations, and the 24-Item Early Onset Scoliosis Questionnaires (EOSQ-24) score. METHODS All primary- and conversion patients (conversion from failed other systems) with SDS and ≥2 years follow-up were included. Radiographic parameters were compared preoperatively, postoperatively and at latest follow-up. Spinal length increase was expressed as mm/year. RESULTS Twenty-four skeletally immature EOS patients (18 primary and 6 conversion cases) were included. There were five idiopathic, seven congenital, three syndromic, and nine neuromuscular EOS patients. Mean age at implantation was 9.1 years (primary: 8.4; conversion: 11.2). Major curve improved from 60.3° to 35.3°, and was maintained at 40.6° at latest follow-up. Mean spring length increase during follow-up was 10.4 mm/year. T1-S1 height increased 9.9mm/year and the instrumented segment height showed a mean increase of 0.7 mm/segment/year. EOSQ-24 scores dropped after surgery from 75.6 to 67.4 but recovered to 75.0 at latest follow-up. In total, 17 reoperations were performed. Ten reoperations were performed to treat 9 implant-related complications. In addition, 7 patients showed spinal growth that exceeded expected growth velocity; their springs were retensioned during a small reoperation. CONCLUSION The 2-year follow-up results from this prospective cohort study indicate that the concept of spring distraction may be feasible as an alternative to current growing spine solutions. Curve correction and growth could be maintained satisfactory without the need for repetitive lengthening procedures. However, as in all growth-friendly implants, complications and reoperations could not be prevented, which emphasizes the need for further improvement.
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Affiliation(s)
- Justin V C Lemans
- Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands.
| | - Sebastiaan P J Wijdicks
- Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands
| | - René M Castelein
- Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Moyo C Kruyt
- Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, the Netherlands
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Mallow GM, Siyaji ZK, Galbusera F, Espinoza-Orías AA, Giers M, Lundberg H, Ames C, Karppinen J, Louie PK, Phillips FM, Pourzal R, Schwab J, Sciubba DM, Wang JC, Wilke HJ, Williams FMK, Mohiuddin SA, Makhni MC, Shepard NA, An HS, Samartzis D. Intelligence-Based Spine Care Model: A New Era of Research and Clinical Decision-Making. Global Spine J 2021; 11:135-145. [PMID: 33251858 PMCID: PMC7882816 DOI: 10.1177/2192568220973984] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- G. Michael Mallow
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
- The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL, USA
| | - Zakariah K. Siyaji
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
- The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL, USA
| | | | - Alejandro A. Espinoza-Orías
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
- The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL, USA
| | - Morgan Giers
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, OR, USA
| | - Hannah Lundberg
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Christopher Ames
- Department of Neurosurgery, University of California San Francisco, CA, USA
| | - Jaro Karppinen
- Medical Research Center Oulu, University of Oulu and Oulu University Hospital, Oulu, Finland
| | | | - Frank M. Phillips
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
- The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL, USA
| | - Robin Pourzal
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Joseph Schwab
- Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA, USA
| | - Daniel M. Sciubba
- Department of Neurosurgery, Johns Hopkins University, Baltimore, MD, USA
| | - Jeffrey C. Wang
- Department of Orthopaedic Surgery, University of Southern California, Los Angeles, CA, USA
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University Medical Centre, Ulm, Germany
| | - Frances M. K. Williams
- Department of Twin Research and Genetic Epidemiology, King’s College London, London, United Kingdom
| | | | - Melvin C. Makhni
- Department of Orthopaedic Surgery, Harvard Medical School, Boston, MA, USA
| | - Nicholas A. Shepard
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
- The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL, USA
| | - Howard S. An
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
- The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL, USA
| | - Dino Samartzis
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
- The International Spine Research and Innovation Initiative, Rush University Medical Center, Chicago, IL, USA
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10
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Agarwal A, Kodigudla M, Kelkar A, Jayaswal D, Goel V, Palepu V. Towards a validated patient-specific computational modeling framework to identify failure regions in traditional growing rods in patients with early onset scoliosis. NORTH AMERICAN SPINE SOCIETY JOURNAL 2021; 5:100043. [PMID: 35141610 PMCID: PMC8820004 DOI: 10.1016/j.xnsj.2020.100043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/07/2020] [Accepted: 12/07/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND While growing rods are an important contribution to early-onset scoliosis treatment, rod fractures are a common complication that require reoperations. A recent retrieval analysis study performed on failed traditional growing rods revealed that there are commonalities among patient characteristics based on the location of rod fracture. However, it remains unknown if these locations correspond to high stress regions in the implanted construct. METHODS A patient-specific finite element scoliotic model was developed to match the pre-operative (pre-op) scoliotic curve of a patient as described in previously published articles, and by using the patient registry information along with biplanar radiographs. A dual stainless-steel traditional growing rod construct was implanted into this scoliotic model and the surgical procedure was simulated to match the post-operative (post-op) scoliotic curve parameters. Muscle stabilization and gravity was simulated through follower load application. Rod distraction magnitudes were chosen based on pre-op to post-op cobb angle correction, and flexion bending load was simulated to identify the high stress regions on the rods. RESULTS The patient-specific finite element model identified two high stress regions on the posterior surface of the rods, one at mid construct and the other adjacent to the distal anchors. This correlated well with the data obtained from the retrieval analysis performed by researchers at U.S. Food and Drug Administration (FDA) which showed the posterior surface of the rod as the fracture initiation site, and the three locations of failure as mid-construct, adjacent to distal anchors, and adjacent to tandem connector. CONCLUSIONS The result of this study confirms that the high stress regions on the growing rods, as identified by the FEA, match the fracture prone sites identified in the retrieval analysis performed at the FDA. This proof-of-concept patient-specific approach can be used to predict sites prone to fracture in growing rods.
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Affiliation(s)
- Aakash Agarwal
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Department of Bioengineering and Orthopaedic Surgery, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 USA
| | - Manoj Kodigudla
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Department of Bioengineering and Orthopaedic Surgery, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 USA
| | - Amey Kelkar
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Department of Bioengineering and Orthopaedic Surgery, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 USA
| | - Daksh Jayaswal
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Department of Bioengineering and Orthopaedic Surgery, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 USA
| | - Vijay Goel
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Department of Bioengineering and Orthopaedic Surgery, University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606 USA
| | - Vivek Palepu
- Center for Devices and Radiological Health, Office of Science and Engineering Laboratories, Division of Applied Mechanics, U.S. Food and Drug Administration, Silver Spring, MD 20993 USA
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Agarwal A, Aker L, Ahmad AA. Active Apex Correction With Guided Growth Technique for Controlling Spinal Deformity in Growing Children: A Modified SHILLA Technique. Global Spine J 2020; 10:438-442. [PMID: 32435564 PMCID: PMC7222691 DOI: 10.1177/2192568219859836] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
STUDY DESIGN A retrospective study. OBJECTIVE To determine if active remodulation in the apex of the curve is possible in scoliosis and kyphoscoliosis patients, using a modified SHILLA; active apex correction (APC) technique for guided growth. METHOD Twenty patients with either scoliosis or kyphoscoliosis underwent a modified SHILLA approach, where instead of apical fusion, APC was applied. In this modified technique, the most wedged vertebra was selected followed by insertion of pedicle screws in the convex side of the vertebrae above and below the wedged one. The convex and concave heights of the wedged and control vertebrae were recorded at the time of the surgery and at follow-up duration, both using computed tomography. RESULTS The wedged vertebra demonstrated in average a 17% (P = .00014) increase in the proportion of concave to convex heights ratio, whereas the control vertebra did not show any relative change in the wedged vertebra heights at the follow-ups. CONCLUSION APC, instead of apical fusion in SHILLA remodulates the apex vertebra, which may in turn help mitigate loss of correction on long term due to crankshafting and adding-on.
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Affiliation(s)
| | - Loai Aker
- Annajah Medical School, Nablus, Palestine
| | - Alaaeldin Azmi Ahmad
- Annajah Medical School, Nablus, Palestine,Alaaeldin Azmi Ahmad, Department of Orthopedics, Annajah Medical School, Nablus, West Bank, Palestine.
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Agarwal A, Aker L, Ahmad AA. Active Apex Correction (Modified SHILLA Technique) Versus Distraction-Based Growth Rod Fixation: What Do the Correction Parameters Say? Spine Surg Relat Res 2020; 4:31-36. [PMID: 32039294 PMCID: PMC7002057 DOI: 10.22603/ssrr.2019-0045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 07/11/2019] [Indexed: 11/23/2022] Open
Abstract
Introduction SHILLA and growth rods are two main surgical correction techniques for patients with early-onset scoliosis. There have been some comparative studies between the two techniques, where a comparison was made between deformity identifying characteristics such as Cobb angle, apical vertebral translation, coronal balance, spinal length gain, etc. However, the SHILLA procedure experiences loss of correction or the reappearance of deformity through crankshafting or adding-on (e.g., distal migration). The current study identifies a solution with a modified approach to SHILLA (which could help in dynamically remodulating the apex of the deformity and mitigating loss of correction) and presents comparative correction data against the long-established traditional growth rod system. Methods The active apex correction (APC) group consisted of 20 patients and the growth rod group consisted of 26 patients, both with the same inclusion and exclusion criteria. The APC surgical procedure involved a modified SHILLA technique, that is, insertion of pedicle screws in the convex side of the vertebrae above and below the wedged one for compression and absence of apical fusion. Results There were no statistical differences between the various spinal parameters (namely, Cobb angle, apical vertebral translation, sagittal balance, and spinal length gain) of the two groups. However, significant differences existed for coronal balance, which in part may have been due to differences in its pre-op value between the two groups. Conclusions APC and the traditional growth rod system showed similar deformity correction parameters at current follow-ups; however, the latter requires multiple surgeries to regularly distract the spine.
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Affiliation(s)
- Aakash Agarwal
- Department of Bioengineering and Orthopaedics Surgery, University of Toledo, Toledo, USA
| | - Loai Aker
- Department of Orthopedics, Annajah Medical School, Nablus, West Bank
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Agarwal A, Kelkar A, Garg Agarwal A, Jayaswal D, Jayaswal A, Shendge V. Device-Related Complications Associated with Magec Rod Usage for Distraction-Based Correction of Scoliosis. Spine Surg Relat Res 2019; 4:148-151. [PMID: 32405561 PMCID: PMC7217671 DOI: 10.22603/ssrr.2019-0041] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/17/2019] [Indexed: 01/22/2023] Open
Abstract
Introduction Recent literature identifies similar failure rates such as anchor pull-out and rod breakage, but a higher unplanned revision surgery with MAGEC rods than with traditional growth rods. Besides known failure modes such as rod fracture, infection, etc., failure to noninvasively distract the rods was cited as the main cause of such unplanned surgeries. The source of these data ranges from multicenter cohort studies to singular case series. These studies included explanted implants that had undergone failure in distraction mechanism, rod fracture, or infection, or had reached their maximum length. Nevertheless, in addition to identifying the overall mode of failure, it is equally important to identify the large-scale incidence of exclusive failures in comparison with standard instrumentation failure modes in spine surgery. Methods The US Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE) databases were searched for reports on MAGEC rods, and on standard instrumentation used for spinal fusion. The adverse events were recorded, tabulated, and analyzed. Results A search of the US FDA MAUDE database yielded reports of 163 device-related adverse events. These included distraction mechanism failure (n=129), rod fracture (n=24), and minor voluntary reports of infection and tissue discoloration (n=10). For standard instrumentation usage in spine surgery, pedicle screw breakage post surgery (n=336), set screw damage during surgery (n=257), rod breakage post surgery (n=175), interbody cage breakage during surgery (n=118), and pedicle screw breakage during surgery (n=75) were identified as the top 5 failure modes. Conclusions The study identified the distraction mechanism failure as the most common and growing complication associated with MAGEC rod usage in children with scoliosis, leading to unplanned invasive revision surgeries.
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Affiliation(s)
- Aakash Agarwal
- Department of Bioengineering and Orthopaedics Surgery, University of Toledo, Toledo, USA
| | - Amey Kelkar
- Department of Bioengineering and Orthopaedics Surgery, University of Toledo, Toledo, USA
| | - Ashish Garg Agarwal
- Department of Orthopedics, Primus Super Speciality Hospital, New Delhi, India
| | - Daksh Jayaswal
- Department of Bioengineering and Orthopaedics Surgery, University of Toledo, Toledo, USA
| | - Arvind Jayaswal
- Department of Orthopedics, Primus Super Speciality Hospital, New Delhi, India
| | - Vithal Shendge
- Department of Bioengineering and Orthopaedics Surgery, University of Toledo, Toledo, USA
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Quantitative Characteristics of Consecutive Lengthening Episodes in Early-onset Scoliosis (EOS) Patients With Dual Growth Rods. Spine (Phila Pa 1976) 2019; 44:397-403. [PMID: 30095792 DOI: 10.1097/brs.0000000000002835] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A prospective single-center study. OBJECTIVE The aim of this study was to record the characteristic forces and lengths observed during distraction episodes in early-onset scoliosis (EOS), and analyze their interdependencies on the key variability among the patients. SUMMARY OF BACKGROUND DATA The goal of the growing-rod technique is to achieve deformity correction alongside maintaining growth of the spine. The deformity correction is achieved during the initial surgery, but follow-up distraction episodes are necessary to maintain the growth. The key variables, under the control of a surgeon, that affect the growth are the applied distraction forces and the distraction lengths. Since the advent of dual growth rod technique, there have been many studies exploring the relationship between these and the actual growth. However, there is sparse evidence on the actual magnitude of distraction forces, and none on its association with patient's parameters such as sex, age, and deformity. METHODS In a consecutive series of 47 patients implanted with dual growth rods, the distraction forces (in N) and the lengths (in mm) achieved during each distraction episode and compared against the episode-specific demographics. The values obtained from each side, that is, concave and convex sides, were averaged to calculate the mean. Statistical analysis was performed using t-distribution because for each normalized time points (distraction episode). RESULTS In cumulative, the distraction force increased by an amount of 268%, with 120% increase in the early stages (distractions episodes 1-6) and 68% increase in the later stages (distractions episodes 6-11), whereas the cumulative decrease in the length over 11 distractions episodes was 47%, with 34% and 20% in the early and later stages, respectively. The study does not identify any significant trend with respect to sex, age, and deformity. CONCLUSION The distraction force and the length increased and decreased respectively with every consecutive distraction episode, with no correlation to sex, age, extent of deformity, or the extent of correction. LEVEL OF EVIDENCE 5.
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