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Zhang H, Ma J, Tian A, lu B, Bai H, Dai J, Wu Y, Chen J, Luo W, Ma X. Analysis of cartilage loading and injury correlation in knee varus deformity. Medicine (Baltimore) 2024; 103:e38065. [PMID: 38728521 PMCID: PMC11081555 DOI: 10.1097/md.0000000000038065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 04/09/2024] [Indexed: 05/12/2024] Open
Abstract
Knee varus (KV) deformity leads to abnormal forces in the different compartments of the joint cavity and abnormal mechanical loading thus leading to knee osteoarthritis (KOA). This study used computer-aided design to create 3-dimensional simulation models of KOA with varying varus angles to analyze stress distribution within the knee joint cavity using finite element analysis for different varus KOA models and to compare intra-articular loads among these models. Additionally, we developed a cartilage loading model of static KV deformity to correlate with dynamic clinical cases of cartilage injury. Different KV angle models were accurately simulated with computer-aided design, and the KV angles were divided into (0°, 3°, 6°, 9°, 12°, 15°, and 18°) 7 knee models, and then processed with finite element software, and the Von-Mises stress distribution and peak values of the cartilage of the femoral condyles, medial tibial plateau, and lateral plateau were obtained by simulating the human body weight in axial loading while performing the static extension position. Finally, intraoperative endoscopy visualization of cartilage injuries in clinical cases corresponding to KV deformity subgroups was combined to find cartilage loading and injury correlations. With increasing varus angle, there was a significant increase in lower limb mechanical axial inward excursion and peak Von-Mises stress in the medial interstitial compartment. Analysis of patients' clinical data demonstrated a significant correlation between varus deformity angle and cartilage damage in the knee, medial plateau, and patellofemoral intercompartment. Larger varus deformity angles could be associated with higher medial cartilage stress loads and increased cartilage damage in the corresponding peak stress area. When the varus angle exceeds 6°, there is an increased risk of cartilage damage, emphasizing the importance of early surgical correction to prevent further deformity and restore knee function.
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Affiliation(s)
- Hongjie Zhang
- Tianjin University of Traditional Chinese Medicine, Tianjin, PR China
- Tianjin Orthopedic Research Institute, Tianjin, PR China
- Kunming Medical University Affiliated Dehong Hospital/Dehongzhou People’s Hospital, Mangshi, China
| | - Jianxiong Ma
- Tianjin University Tianjin Hospital, Tianjin, PR China
- Tianjin Orthopedic Research Institute, Tianjin, PR China
| | - Aixian Tian
- Tianjin University Tianjin Hospital, Tianjin, PR China
- Tianjin Orthopedic Research Institute, Tianjin, PR China
| | - Bin lu
- Tianjin University Tianjin Hospital, Tianjin, PR China
- Tianjin Orthopedic Research Institute, Tianjin, PR China
| | - Haohao Bai
- Tianjin University Tianjin Hospital, Tianjin, PR China
- Tianjin Orthopedic Research Institute, Tianjin, PR China
| | - Jing Dai
- Tianjin Medical University, Tianjin, PR China
| | - Yanfei Wu
- Tianjin Medical University, Tianjin, PR China
| | - Jiahui Chen
- Tianjin Medical University, Tianjin, PR China
| | - Wei Luo
- Tianjin University Tianjin Hospital, Tianjin, PR China
| | - Xinlong Ma
- Tianjin University Tianjin Hospital, Tianjin, PR China
- Tianjin Orthopedic Research Institute, Tianjin, PR China
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2
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Patel RV, Yearley AG, Isaac H, Chalif EJ, Chalif JI, Zaidi HA. Advances and Evolving Challenges in Spinal Deformity Surgery. J Clin Med 2023; 12:6386. [PMID: 37835030 PMCID: PMC10573859 DOI: 10.3390/jcm12196386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/03/2023] [Accepted: 10/04/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Surgical intervention is a critical tool to address adult spinal deformity (ASD). Given the evolution of spinal surgical techniques, we sought to characterize developments in ASD correction and barriers impacting clinical outcomes. METHODS We conducted a literature review utilizing PubMed, Embase, Web of Science, and Google Scholar to examine advances in ASD surgical correction and ongoing challenges from patient and clinician perspectives. ASD procedures were examined across pre-, intra-, and post-operative phases. RESULTS Several factors influence the effectiveness of ASD correction. Standardized radiographic parameters and three-dimensional modeling have been used to guide operative planning. Complex minimally invasive procedures, targeted corrections, and staged procedures can tailor surgical approaches while minimizing operative time. Further, improvements in osteotomy technique, intraoperative navigation, and enhanced hardware have increased patient safety. However, challenges remain. Variability in patient selection and deformity undercorrection have resulted in heterogenous clinical responses. Surgical complications, including blood loss, infection, hardware failure, proximal junction kyphosis/failure, and pseudarthroses, pose barriers. Although minimally invasive approaches are being utilized more often, clinical validation is needed. CONCLUSIONS The growing prevalence of ASD requires surgical solutions that can lead to sustained symptom resolution. Leveraging computational and imaging advances will be necessary as we seek to provide comprehensive treatment plans for patients.
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Affiliation(s)
- Ruchit V. Patel
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (R.V.P.); (A.G.Y.); (E.J.C.); (J.I.C.)
- Harvard Medical School, Boston, MA 02115, USA
| | - Alexander G. Yearley
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (R.V.P.); (A.G.Y.); (E.J.C.); (J.I.C.)
- Harvard Medical School, Boston, MA 02115, USA
| | - Hannah Isaac
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (R.V.P.); (A.G.Y.); (E.J.C.); (J.I.C.)
| | - Eric J. Chalif
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (R.V.P.); (A.G.Y.); (E.J.C.); (J.I.C.)
- Harvard Medical School, Boston, MA 02115, USA
| | - Joshua I. Chalif
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (R.V.P.); (A.G.Y.); (E.J.C.); (J.I.C.)
- Harvard Medical School, Boston, MA 02115, USA
| | - Hasan A. Zaidi
- Department of Neurosurgery, Brigham and Women’s Hospital, Boston, MA 02115, USA; (R.V.P.); (A.G.Y.); (E.J.C.); (J.I.C.)
- Harvard Medical School, Boston, MA 02115, USA
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3
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Sursal T, Kim HJ, Sardi JP, Yen CP, Smith JS. Use of Tethers for Proximal Junctional Kyphosis Prophylaxis in Adult Spinal Deformity Surgery: A Review of Current Clinical Evidence. Int J Spine Surg 2023; 17:S26-S37. [PMID: 37673684 PMCID: PMC10626134 DOI: 10.14444/8515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023] Open
Abstract
BACKGROUND Surgery for adult spinal deformity (ASD) often involves long-segment posterior instrumentation that introduces stress at the proximal junction that can result in proximal junctional kyphosis (PJK) or proximal junctional failure (PJF). Recently, the use of tethers at the proximal junction has been proposed as a means of buffering the transitional stresses and reducing the risk of PJK/PJF. Our objectives are to summarize the clinical literature on proximal junctional tethers for PJK/PJF prophylaxis. METHODS Articles published between 1 January 2000 and 10 November 2022 were identified via a PubMed search using combinations of the search terms "spine surgery," "ASD," "complication," "surgery," "PJK," "PJF," "tether," "sublaminar band," and "prophylaxis." No restrictions were placed on the number of patients, surgical indications, or surgical procedures. Relevant articles were reviewed and summarized. RESULTS Fifteen articles were identified, including 2 prospective cohorts (Level II), 10 retrospective cohorts (Level III), and 3 retrospective case series (Level IV). All studies were published between 2016 and 2022, and all focused on ASD patient populations. The mean age in each study ranged from 55 to 69 years, and most studies had a mean follow-up of at least 12 months (range, 5.5-45.4 months). Eleven studies used a polyethylene tether, 2 used soft sublaminar cables, and 2 used semitendinous allograft. The tether extended to the UIV+1 or UIV+2, passing either through or around the spinous processes, in 13 studies. In the remaining 2 studies, the tether was passed sublaminar at the UIV+1. Fourteen studies favored the use of tethers with regard to reduction of PJK/PJF rates, and one demonstrated similar rates of PJK between the tether and no-tether groups. CONCLUSIONS PJK/PJF remain major challenges in ASD surgery. Most early studies suggest that the use of tethers for ligamentous augmentation may help to mitigate the development of PJK/PJF. However, the multifactorial etiology of PJK/PJF makes it unlikely that any single technique will solve this complex problem. Further study is needed to address not only the effectiveness of junctional tethers but also to clarify whether there are optimal tether configurations, tether materials, and tether tension. LEVEL EVIDENCE 3.
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Affiliation(s)
- Tolga Sursal
- Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA
| | - Han Jo Kim
- Department of Orthopedic Surgery, Hospital for Special Surgery, New York City, NY, USA
| | - Juan Pablo Sardi
- Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA
| | - Chun-Po Yen
- Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA
| | - Justin S Smith
- Department of Neurosurgery, University of Virginia, Charlottesville, VA, USA
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Yagi M, Yamanouchi K, Fujita N, Funao H, Ebata S. Proximal Junctional Failure in Adult Spinal Deformity Surgery: An In-depth Review. Neurospine 2023; 20:876-889. [PMID: 37798983 PMCID: PMC10562237 DOI: 10.14245/ns.2346566.283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 10/07/2023] Open
Abstract
Adult spinal deformity (ASD) surgery aims to correct abnormal spinal curvature in adults, leading to improved functionality and reduced pain. However, this surgery is associated with various complications, one of which is proximal junctional failure (PJF). PJF can have a significant impact on a patient's quality of life, necessitating a comprehensive understanding of its causes and the development of effective management strategies. This review aims to provide an in-depth understanding of PJF in ASD surgery. PJF is a complex complication resulting from a multitude of factors including patient characteristics, surgical techniques, and postoperative management. Age, osteoporosis, overcorrection of sagittal alignment, and poor bone quality are identified as significant risk factors. The clinical implications of PJF are substantial, often requiring revision surgery and causing a considerable decrease in patients' quality of life. Prevention strategies include careful preoperative planning, appropriate patient selection, and optimization of surgical techniques. Treatment often necessitates a multifaceted approach, including surgical intervention and the management of underlying risk factors. Predictive modeling is an emerging field that may offer a promising avenue for the risk stratification of patients and individualized preventive strategies. A thorough understanding of PJF's pathogenesis, risk factors, and clinical implications is essential for surgeons involved in ASD surgery. Current preventive measures and treatment strategies aim to mitigate the risk and manage the complications of PJF, but the complication cannot be entirely prevented. Future research should focus on the development of more effective preventive and treatment strategies, and predictive models could be valuable in this pursuit.
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Affiliation(s)
- Mitsuru Yagi
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Kento Yamanouchi
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Naruhito Fujita
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Haruki Funao
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
| | - Shigeto Ebata
- Department of Orthopaedic Surgery, International University of Health and Welfare, School of Medicine, Narita, Japan
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5
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Biomechanical Effect of Using Cement Augmentation to Prevent Proximal Junctional Kyphosis in Long-Segment Fusion: A Finite Element Study. J Med Biol Eng 2023. [DOI: 10.1007/s40846-023-00772-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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6
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Wu Y, Jin X, Zhao X, Wang Y, Bai H, Lu B, Tong X, Ma J, Ma X. Computer-aided Design of Distal Femoral Osteotomy for the Valgus Knee and Effect of Correction Angle on Joint Loading by Finite Element Analysis. Orthop Surg 2022; 14:2904-2913. [PMID: 36151783 PMCID: PMC9627055 DOI: 10.1111/os.13440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/15/2022] [Accepted: 07/16/2022] [Indexed: 11/30/2022] Open
Abstract
Objective Lateral open‐wedge distal femoral osteotomy (DFO) has been used to treat valgus deformity of the knee, with good clinical outcomes. However, there is a lack of biomechanical studies regarding the angle of correction. The objective of this study was to apply computer‐aided design (CAD) for osteotomy planning in a three‐dimensional (3D) anatomical model and to assess the biomechanical differences among the varying correction angles on joint loading by finite element analysis (FEA). Methods To model different angles of lateral open‐wedge DFO correction, the CAD software package Mimics 21.0 was used to accurately simulate the operated knee. The femur was cut to 0°, 2°, 4°, 6°, 8°, and 10° of varus (equivalent to hip‐knee‐ankle angles of 180°, 178°, 176°, 174°, 172°, and 170°, respectively). The original knee model and the corrected models were processed by FE software. Then, the FE models were subjected to an axial force to obtain the von Mises stress (VMS) and shear stress distributions within the femoral cartilages and menisci. Results Under a compressive load of 740 N, the highest VMS in lateral and medial compartments of the intact knee model was 3.418 and 3.303 MPa. The maximum value of both the VMS and the shear stress in the lateral compartment decreased as the varus angle increased, but the corresponding values in the medial compartment increased. When the hip‐knee‐ankle (HKA) angle was 180°, the VMS in the lateral and medial compartments was balanced (3.418 and 3.303 MPa, respectively). Meanwhile, when the HKA angle was 178° (3.488 and 3.625 MPa, respectively), the shear stress in the lateral and medial compartments was balanced. In addition, the magnitude of change in the stress was significantly higher in the medial compartment (90.9%) than in the lateral compartment (19.3%). Conclusion The optimal correction angle of the valgus knee is close to neutral alignment or slightly varus (0° ‐ 2°). Overcorrection is not recommended, as it can result in a steep increase of the stress within the medial compartment and may accelerate the process of medial compartment OA.
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Affiliation(s)
- Yanfei Wu
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, China.,Tianjin Hospital, Tianjin University, Tianjin, China
| | - Xin Jin
- Tianjin Hospital, Tianjin University, Tianjin, China
| | - Xingwen Zhao
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, China.,Tianjin Hospital, Tianjin University, Tianjin, China
| | - Ying Wang
- Tianjin Hospital, Tianjin University, Tianjin, China
| | - Haohao Bai
- Tianjin Hospital, Tianjin University, Tianjin, China
| | - Bin Lu
- Tianjin Hospital, Tianjin University, Tianjin, China
| | - Xue Tong
- Tianjin Hospital, Tianjin University, Tianjin, China
| | - Jianxiong Ma
- Tianjin Hospital, Tianjin University, Tianjin, China
| | - Xinlong Ma
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, China.,Tianjin Hospital, Tianjin University, Tianjin, China
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7
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Pereira BDA, Lehrman JN, Sawa AG, Wangsawatwong P, Godzik J, Xu DS, Turner JD, Kelly BP, Uribe JS. Biomechanical Effects of Proximal Polyetheretherketone Rod Extension on the Upper Instrumented and Adjacent Levels in a Human Long-Segment Construct: A Cadaveric Model. Neurospine 2022; 19:828-837. [PMID: 36203305 PMCID: PMC9537850 DOI: 10.14245/ns.2244146.073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/12/2022] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE The high mechanical stress zone at the sudden transition from a rigid to flexible region is involved in proximal junctional kyphosis (PJK) physiopathology. We evaluated the biomechanical performance of polyetheretherketone (PEEK) rods used as a nontraditional long semirigid transition phase from a long-segment metallic rod construct to the nonfused thoracic spine. METHODS Pure moment range of motion (ROM) tests (7.5 Nm) were performed on 7 cadaveric spine segments followed by compression (200 N). Specimens were tested in the following conditions: (1) intact; (2) T10-pelvis pedicle screws and rods (PSRs); and (3) extending the proximal construct to T6 using PEEK rods (PSR+PEEK). T10-11 rod strain, T9 anterolateral bone strain, and T10 screw bending moments were analyzed. RESULTS At the upper instrumented vertebra (UIV)+1, PSR+PEEK versus PSR significantly decreased ROM in flexion (115%, p = 0.02), extension (104%, p = 0.003), left lateral bending (46%, p = 0.02), and right lateral bending (63%, p = 0.008). Also, at UIV+1, PSR+PEEK versus intact significantly decreased ROM in flexion (111%, p = 0.01) and extension (105%, p = 0.003). The UIV+1 anterior column bone strain was significantly reduced with PSR+PEEK versus PSR during right lateral bending (p = 0.02). Rod strain polarities reversed with PEEK rods in all loading directions except compression. CONCLUSION Extending a long-segment construct using PEEK rods caused a decrease in adjacent-level hypermobility as a consequence of long-segment immobilization and also redistributed the strain on the UIV and adjacent levels, which might contribute to PJK physiopathology. Further studies are necessary to observe the clinical outcomes of this technique.
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Affiliation(s)
- Bernardo de Andrada Pereira
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Jennifer N. Lehrman
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Anna G.U. Sawa
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Piyanat Wangsawatwong
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Jakub Godzik
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - David S. Xu
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Jay D. Turner
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
| | - Brian P. Kelly
- Spinal Biomechanics Laboratory, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA,Corresponding Author Brian P. Kelly c/o Neuroscience Publications; Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center 350 W. Thomas Rd.; Phoenix, AZ 85013, USA
| | - Juan S. Uribe
- Department of Neurosurgery, Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ, USA
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8
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Yagi M, Suzuki S, Okada E, Nori S, Tsuji O, Nagoshi N, Nakamura M, Matsumoto M, Watanabe K. Sublaminar Tethers Significantly Reduce the Risk of Proximal Junctional Failure in Surgery for Severe Adult Spinal Deformity: A Propensity Score-matched Analysis. Clin Spine Surg 2022; 35:E496-E503. [PMID: 35034048 DOI: 10.1097/bsd.0000000000001294] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 12/05/2021] [Indexed: 12/12/2022]
Abstract
STUDY DESIGN This was a retrospective case series of prospectively collected data. OBJECTIVE The present study first described the effect of sublaminar tethering (SLT) on proximal junctional failure (PJF) in adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA PJF is a devastating complication following ASD surgery. Teriparatide administration and spinous process tethering have been reported as alternatives for the prevention of PJF, but a clinically effective prevention strategy is still a matter of debate. MATERIALS AND METHODS We used data from an ASD database that included 381 patients with ASD (minimum 2-y follow-up). Among them, the data of patients who had a severe sagittal deformity and had surgery from the lower thoracic spine (T9-T11) to the pelvis were extracted and propensity score matched by age, sex, body mass index, bone mineral density, curve type, sagittal alignment, and fused level to clarify whether SLT prevented the development of PJF [SLT vs. control (CTR); age: 67±7 vs. 66±8 y, T-score: -1.4±0.7 vs. -1.3±0.6, body mass index: 22±4 vs. 22±5 kg/m2, C7 sagittal vertical axis (C7SVA): 12±7 vs. 11±5 cm, pelvic incidence-lumbar lordosis (PI-LL): 51±22 vs. 49±21 degrees, pelvic tilt (PT): 36±10 vs. 34±10 degrees, level fused: 11±2 vs. 11±2]. Sixty-four patients were matched into 32 pairs and compared in terms of the postoperative alignment and frequency of PJF. RESULTS Two years postoperatively, C7SVA and PT were significantly larger in the CTR group, while no significant difference in PI-LL was found (C7SVA: 3±3 vs. 6±4 cm, P<0.01, PT: 16±6 vs. 24±9 degrees, P<0.01, PI-LL: 7±9 vs. 11±11 degrees, P=0.22). The proximal junctional angle was significantly greater in the CTR group (proximal junctional kyphosis: 8±8 vs. 17±13 degrees, P<0.01). The incidence of PJF was significantly lower in the SLT group (3% vs. 25%, P=0.03), with an odds ratio of 0.1 (95% confidence interval: 0.0-0.8, P=0.03). CONCLUSION In the propensity score-matched cohort, the incidence of PJF was significantly lower in the SLT group. SLT is a promising procedure that may reduce the risk of PJF in severe ASD surgery.
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Affiliation(s)
- Mitsuru Yagi
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Satoshi Suzuki
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Eijiro Okada
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Satoshi Nori
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Osahiko Tsuji
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Narihito Nagoshi
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Masaya Nakamura
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Morio Matsumoto
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
| | - Kota Watanabe
- Department of Orthopedic Surgery, Keio University School of Medicine
- Keio Spine Research Group, Tokyo, Japan
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9
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Lee NJ, Sardar ZM, Boddapati V, Mathew J, Cerpa M, Leung E, Lombardi J, Lenke LG, Lehman RA. Can Machine Learning Accurately Predict Postoperative Compensation for the Uninstrumented Thoracic Spine and Pelvis After Fusion From the Lower Thoracic Spine to the Sacrum? Global Spine J 2022; 12:559-566. [PMID: 33030054 PMCID: PMC9109562 DOI: 10.1177/2192568220956978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
STUDY DESIGN Consecutively collected cases. OBJECTIVE To determine if a machine-learning (ML) program can accurately predict the postoperative thoracic kyphosis through the uninstrumented thoracic spine and pelvic compensation in patients who undergo fusion from the lower thoracic spine (T10 or T11) to the sacrum. METHODS From 2015 to 2019, a consecutive series of adult (≥18 years old) patients with adult spinal deformity underwent corrective spinal fusion from the lower thoracic spine (T10 or T11) to the sacrum. Deidentified data was processed by a ML system-based platform to predict the postoperative thoracic kyphosis (TK) and pelvic tilt (PT) for each patient. To validate the ML model, the postoperative TK (T4-T12, instrumented thoracic, and uninstrumented thoracic) and the pelvic tilt were compared against the predicted values. RESULTS A total of 20 adult patients with a minimum 6-month follow-up (mean: 22.4 ± 11.3 months) were included in this study. No significant differences were observed for TK (predicted 37.6° vs postoperative 38.3°, P = .847), uninstrumented TK (predicted 33.9° vs postoperative 29.8°, P = .188), and PT (predicted 23.4° vs postoperative 22.7°, P = .754). The predicted PT and the TK of the uninstrumented thoracic spine correlated well with postoperative values (uninstrumented TK: R2 = 0.764, P < .001; PT: R2 = 0.868, P < .001). The mean error with which kyphosis through the uninstrumented thoracic spine can be measured was 4.8° ± 4.0°. The mean error for predicting PT was 2.5° ± 1.7°. CONCLUSION ML algorithms can accurately predict the spinopelvic compensation after spinal fusion from the lower thoracic spine to the sacrum. These findings suggest that surgeons may be able to leverage this technology to reduce the risk of proximal junctional kyphosis in this population.
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Affiliation(s)
- Nathan J. Lee
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA,Nathan J. Lee, Columbia University Medical
Center, 161 Fort Washington Avenue, New York, NY 10032, USA.
| | - Zeeshan M. Sardar
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
| | - Venkat Boddapati
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
| | - Justin Mathew
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
| | - Meghan Cerpa
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
| | - Eric Leung
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
| | - Joseph Lombardi
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
| | - Lawrence G. Lenke
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
| | - Ronald A. Lehman
- Columbia University Medical Center,
The Och Spine Hospital at New York–Presbyterian, New York, NY, USA
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10
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Zhao G, Wang X, Liu D, Wu K, Zhao J, Fei W. A biomechanical study of ligament tethers strengthening for the prevention of proximal junctional kyphosis after posterior long-segment spinal fusion. Clin Biomech (Bristol, Avon) 2022; 94:105621. [PMID: 35299117 DOI: 10.1016/j.clinbiomech.2022.105621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 03/02/2022] [Accepted: 03/08/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Proximal junctional kyphosis is a known complication of posterior long-segment thoracolumbar fusion. Here, the biomechanical effectiveness of ligament tethers strengthening and vertebral body augmentation, in proximal junctional kyphosis prevention was explored using the finite element analysis. METHODS Based on a validated model of T1-L5 with the pedicle screw system instrumented T8-L5, strengthening models with different strategies were created to assess the range of motion in proximal vertebrae, vertebrae stress, pedicle screw stress, and pressure on intervertebral discs during extension, flexion, lateral bending, and axial rotation motions. Strengthening strategies included two- and three-level posterior ligament tethers (TE-T7-T9 and TE-T6-T9), and tethers with T7 &T8 vertebral body augmentation (TECE-T7-T9 and TECE-T6-T9). FINDINGS Compared to the spinal fusion model, the ligament tethers strengthening significantly reduced the flexion-extension range of motion difference among the proximal vertebrae. During the flexion-extension motion, the T8 vertebra stresses in the TE-T7-T9, TE-T6-T9, TECE-T7-T9, and TECE-T6-T9 models were distinctively reduced, the values decreased by 26.8%, 28.3%, 28.8%, and 9.6%, respectively, during flexion, and by 21.9%, 35.2%, 23%, and 18.6%, respectively, during extension. In the strengthening models, the maximum stresses on the T7/T8 intervertebral disc in the TE-T6-T9 model were reduced by 13.8% during flexion and by 14.7% during extension. INTERPRETATION Based on our results, the ligament strengthening configuration of the three-level posterior tethers produced a more gradual transition in range of motion, vertebrae stresses, and intervertebral discs stress between the fused and non-fused segments, especially during flexion-extension, which may significantly decrease the proximal junctional kyphosis biomechanical risk.
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Affiliation(s)
- Gaiping Zhao
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China.
| | - Xiaoyu Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Dongqing Liu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Kunneng Wu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Jian Zhao
- Department of Orthopedics, Western Theater General Hospital, Chengdu, China
| | - Wang Fei
- Chang-Hai Hospital, The Second Military Medical University, Shanghai, China
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11
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Du X, Jiang G, Zhu Y, Luo W, Ou Y. A predictive scoring system for proximal junctional kyphosis after posterior internal fixation in elderly patients with chronic osteoporotic vertebral fracture: A single-center diagnostic study. Front Endocrinol (Lausanne) 2022; 13:923778. [PMID: 35937792 PMCID: PMC9354091 DOI: 10.3389/fendo.2022.923778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/30/2022] [Indexed: 11/29/2022] Open
Abstract
OBJECTIVE To establish a predictive scoring system for proximal junctional kyphosis (PJK) after posterior internal fixation in elderly patients with chronic osteoporotic vertebral fracture (COVF). MATERIALS AND METHODS The medical records of 88 patients who were diagnosed with COVF and underwent posterior internal fixation in our hospital from January 2013 to December 2017 were retrospectively analyzed. The included patients were divided into two groups according to whether they suffered PJK after surgery, namely, the PJK group (25 cases) and non-PJK group (63 cases). The following clinical characteristics were recorded and analyzed: age, gender, body mass index (BMI), bone mineral density (BMD), smoking history, fracture segment, proximal junction angle, sagittal vertebral axis, pelvic incidence (PI)-lumbar lordosis (LL), pelvic tilt (PT), sacral slope (SS), posterior ligamentous complex (PLC) injury, upper instrumented vertebra, lower instrumented vertebra, and the number of fixed segments. The prevalence of these clinical characteristics in the PJK group was evaluated, and the scoring system was established using logistic regression analysis. The performance of the scoring system was also prospectively validated. RESULTS The predictive scoring system was established based on five clinical characteristics confirmed as significant predictors of PJK, namely, age > 70 years, BMI > 28 kg/m2, BMD < -3.5 SD, preoperative PI-LL > 20°, and PLC injury. PJK showed a significantly higher score than non-PJK (7.80 points vs. 2.83 points, t=9.556, P<0.001), and the optimal cutoff value for the scoring system was 5 points. The sensitivity and specificity of the scoring system for predicting postoperative PJK were 80.00% and 88.89%, respectively, in the derivation set and 75.00% and 80.00% in the validation set. CONCLUSION The predictive scoring system was confirmed with satisfactory sensitivity and specificity in predicting PJK after posterior internal fixation in elderly COVF patients. The risk of postoperative PJK in patients with a score of 6-11 is high, while the score of 0-5 is low.
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Affiliation(s)
- Xing Du
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, China
| | - Guanyin Jiang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, China
| | - Yong Zhu
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, China
| | - Wei Luo
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, China
| | - Yunsheng Ou
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, China
- *Correspondence: Yunsheng Ou,
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12
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Yamamoto S, Malakoutian M, Theret M, Street J, Rossi F, Brown SHM, Saito M, Oxland TR. The Effect of Posterior Lumbar Spinal Surgery on Biomechanical Properties of Rat Paraspinal Muscles 13 Weeks After Surgery. Spine (Phila Pa 1976) 2021; 46:E1125-E1135. [PMID: 34156788 DOI: 10.1097/brs.0000000000004036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Preclinical study in rodents. OBJECTIVE To investigate changes in biomechanical properties of paraspinal muscles following a posterior spinal surgery in an animal model. SUMMARY OF BACKGROUND DATA Posterior spine surgery damages paraspinal musculature per histological and imaging studies. The biomechanical effects of these changes are unknown. METHODS 12 Sprague-Dawley rats were divided equally into sham and surgical injury (SI) groups. For sham, the skin and lumbodorsal fascia were incised at midline. For SI, the paraspinal muscles were detached from the vertebrae, per normal procedure. Thirteen weeks postsurgery, multifidus and longissimus biopsies at L1, L3, and L5 levels were harvested on the right. From each biopsy, three fibers and three to six bundles of fibers (∼10-20 fibers ensheathed in their extracellular matrix) were tested mechanically to measure their passive elastic modulus. The collagen content and fatty infiltration of each biopsy were also examined histologically by immunofluorescence staining. Nonparametric statistical methods were used with a 1.25% level of significance. RESULTS A total of 220 fibers and 279 bundles of fibers were tested. The elastic moduli of the multifidus and longissimus fibers and longissimus fiber bundles were not significantly different between the SI and sham groups. However, the elastic modulus of multifidus fiber bundles was significantly greater in the SI group compared to sham (SI median 82 kPa, range 23-284; sham median 38 kPa, range 23-50, P = 0.0004). The elastic modulus of multifidus fiber bundles in the SI group was not statistically different between spinal levels (P = 0.023). For histology, only collagen I deposition in multifidus was significantly greater in the SI group (median 20.8% vs. 5.8% for sham, P < 0.0001). CONCLUSION The surgical injury increased the passive stiffness of the multifidus fiber bundles. Increased collagen content in the extracellular matrix is the likely reason and these changes may be important in the postoperative compensation of the spine.Level of Evidence: N/A.
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Affiliation(s)
- Shun Yamamoto
- Department of Orthopaedics, The University of British Columbia, Vancouver, Canada
- International Collaboration on Repair Discoveries (ICORD), The University of British Columbia, Vancouver, Canada
- Department of Orthopaedic Surgery, Jikei University School of Medicine, Tokyo, Japan
| | - Masoud Malakoutian
- International Collaboration on Repair Discoveries (ICORD), The University of British Columbia, Vancouver, Canada
- Department of Mechanical Engineering, The University of British Columbia, Vancouver, Canada
| | - Marine Theret
- School of Biomedical Engineering, The University of British Columbia, Vancouver, Canada
- Department of Medical Genetics, The University of British Columbia, Vancouver, Canada
| | - John Street
- Department of Orthopaedics, The University of British Columbia, Vancouver, Canada
- International Collaboration on Repair Discoveries (ICORD), The University of British Columbia, Vancouver, Canada
| | - Fabio Rossi
- School of Biomedical Engineering, The University of British Columbia, Vancouver, Canada
- Department of Medical Genetics, The University of British Columbia, Vancouver, Canada
| | - Stephen H M Brown
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Canada
| | - Mitsuru Saito
- Department of Orthopaedic Surgery, Jikei University School of Medicine, Tokyo, Japan
| | - Thomas R Oxland
- Department of Orthopaedics, The University of British Columbia, Vancouver, Canada
- International Collaboration on Repair Discoveries (ICORD), The University of British Columbia, Vancouver, Canada
- Department of Mechanical Engineering, The University of British Columbia, Vancouver, Canada
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Terai H, Takahashi S, Yasuda H, Konishi S, Maeno T, Kono H, Matsumura A, Namikawa T, Kato M, Hoshino M, Tamai K, Toyoda H, Suzuki A, Nakamura H. Direct Lateral Corpectomy and Reconstruction Using an Expandable Cage Improves Local Kyphosis but Not Global Sagittal Alignment. J Clin Med 2021; 10:jcm10174012. [PMID: 34501460 PMCID: PMC8432512 DOI: 10.3390/jcm10174012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 08/30/2021] [Accepted: 09/03/2021] [Indexed: 01/07/2023] Open
Abstract
Recently, an expandable cage equipped with rectangular footplates has been used for anterior vertebral replacement in osteoporotic vertebral fracture (OVF). However, the postoperative changes in global alignment have not been elucidated. The purpose of this study was to evaluate local and global spinal alignment after anterior and posterior spinal fixation (APSF) using an expandable cage in elderly OVF patients. This retrospective multicenter review assessed 54 consecutive patients who underwent APSF for OVF. Clinical outcomes were compared between postoperative sagittal vertical axis (SVA) > 95 mm and ≤95 mm groups to investigate the impact of malalignment. SVA improved by only 18.7 mm (from 111.8 mm to 93.1 mm). VAS score of back pain at final follow-up was significantly higher in patients with SVA > 95 mm than SVA ≤ 95 mm (42.4 vs. 22.6, p = 0.007). Adjacent vertebral fracture after surgery was significantly more frequent in the SVA > 95 mm (37% vs. 11%, p = 0.038). Multiple logistic regression showed significantly increased OR for developing adjacent vertebral fracture (OR = 4.76, 95% CI 1.10–20.58). APSF using the newly developed cage improves local kyphotic angle but not SVA. The main cause for the spinal malalignment after surgery was postoperative development of adjacent vertebral fractures.
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Affiliation(s)
- Hidetomi Terai
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (H.T.); (M.H.); (K.T.); (H.T.); (A.S.); (H.N.)
| | - Shinji Takahashi
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (H.T.); (M.H.); (K.T.); (H.T.); (A.S.); (H.N.)
- Correspondence: ; Tel.: +81-06-6645-3851
| | - Hiroyuki Yasuda
- Department of Orthopaedic Surgery, Osaka General Hospital of West Japan Railway Company, Osaka 545-0053, Japan; (H.Y.); (S.K.)
| | - Sadahiko Konishi
- Department of Orthopaedic Surgery, Osaka General Hospital of West Japan Railway Company, Osaka 545-0053, Japan; (H.Y.); (S.K.)
| | - Takafumi Maeno
- Department of Orthopaedic Surgery, Ishikiri Seiki Hospital, Osaka 579-8026, Japan; (T.M.); (H.K.)
| | - Hiroshi Kono
- Department of Orthopaedic Surgery, Ishikiri Seiki Hospital, Osaka 579-8026, Japan; (T.M.); (H.K.)
| | - Akira Matsumura
- Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka 534-0021, Japan; (A.M.); (T.N.); (M.K.)
| | - Takashi Namikawa
- Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka 534-0021, Japan; (A.M.); (T.N.); (M.K.)
| | - Minori Kato
- Department of Orthopaedic Surgery, Osaka City General Hospital, Osaka 534-0021, Japan; (A.M.); (T.N.); (M.K.)
| | - Masatoshi Hoshino
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (H.T.); (M.H.); (K.T.); (H.T.); (A.S.); (H.N.)
| | - Koji Tamai
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (H.T.); (M.H.); (K.T.); (H.T.); (A.S.); (H.N.)
| | - Hiromitsu Toyoda
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (H.T.); (M.H.); (K.T.); (H.T.); (A.S.); (H.N.)
| | - Akinobu Suzuki
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (H.T.); (M.H.); (K.T.); (H.T.); (A.S.); (H.N.)
| | - Hiroaki Nakamura
- Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka 545-8585, Japan; (H.T.); (M.H.); (K.T.); (H.T.); (A.S.); (H.N.)
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14
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Rabinovich EP, Buell TJ, Sardi JP, Lazaro BCR, Shaffrey CI, Smith JS. A Novel Weave Tether Technique for Proximal Junctional Kyphosis Prevention in 71 Adult Spinal Deformity Patients: A Preliminary Case Series Assessing Early Complications and Efficacy. Oper Neurosurg (Hagerstown) 2021; 21:393-399. [PMID: 34467979 DOI: 10.1093/ons/opab305] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 07/02/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Proximal junctional kyphosis (PJK) rates may be as high as 69.4% after adult spinal deformity (ASD) surgery. PJK is one of the greatest unsolved challenges in long-segment fusions for ASD and remains a common indication for costly and impactful revision surgery. Junctional tethers may help to reduce the occurrence of PJK by attenuating adjacent-segment stress. OBJECTIVE To report our experience and assess early safety associated with a novel "weave-tether technique" (WTT) for PJK prophylaxis in a large series of patients. METHODS This single-center retrospective study evaluated consecutive patients who underwent ASD surgery including WTT between 2017 and 2018. Patient demographics, operative details, standard radiographic measurements, and complications were analyzed. RESULTS A total of 71 patients (mean age 66 ± 12 yr, 65% women) were identified. WTT included application to the upper-most instrumented vertebrae (UIV) + 1 and UIV + 2 in 38(53.5%) and 33(46.5%) patients, respectively. No complications directly attributed to WTT usage were identified. For patients with radiographic follow-up (96%; mean duration 14 ± 12 mo), PJK occurred in 15% (mean 1.8 ± 1.0 mo postoperatively). Proximal junctional angle increased an average 4° (10° to 14°, P = .004). Rates of symptomatic PJK and revision for PJK were 8.8% and 2.9%, respectively. CONCLUSION Preliminary results support the safety of the WTT for PJK prophylaxis. Approximately 15% of patients developed radiographic PJK, no complications were directly attributed to WTT usage, and the revision rate for PJK was low. These early results warrant future research to assess longer-term efficacy of the WTT for PJK prophylaxis in ASD surgery.
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Affiliation(s)
- Emily P Rabinovich
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Thomas J Buell
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Juan P Sardi
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Bruno C R Lazaro
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Christopher I Shaffrey
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA.,Department of Orthopedic Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Justin S Smith
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
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15
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Rabinovich EP, Snyder MH, McClure JJ, Buell TJ, Smith JS, Shaffrey CI, Buchholz AL. Posterior Polyethylene Tethers Reduce Occurrence of Proximal Junctional Kyphosis After Multilevel Spinal Instrumentation for Adult Spinal Deformity: A Retrospective Analysis. Neurosurgery 2021; 89:227-235. [PMID: 33971008 DOI: 10.1093/neuros/nyab123] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 01/30/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Proximal junctional kyphosis (PJK) is a common postoperative complication after adult spinal deformity (ASD) surgery and may manifest with neurological decline, worsening spinal deformity, and spinal instability, which warrant reoperation. Rates of PJK may be as high as 69.4% after ASD surgery. OBJECTIVE To evaluate the efficacy of junctional tethers for PJK prophylaxis after multilevel instrumented surgery for ASD with minimum 2-yr follow-up. METHODS Single-center retrospective analysis of adult patients (age ≥18 yr) who underwent ASD surgery with index operations performed between November 2010 and June 2016 and achieved minimum 2-yr follow-up. Patients with ASD were subdivided into 3 treatment cohorts based on institutional protocol: no tether (NT), polyethylene tether-only (TO), and tether with crosslink (TC). PJK was defined as a proximal junctional angle (PJA) >10° and 10° greater than the corresponding preoperative measurement. Patient demographics, operative details, standard radiographic scoliosis measurements (including PJA and assessment of PJK), and complications were analyzed. RESULTS Of 184 patients, 146 (79.3%) achieved minimum 2-yr follow-up (mean = 45 mo; mean age = 67 yr; 67.8% women). PJK rates reported for the NT, TO, and TC cohorts were 60.7% (37/61), 35.7% (15/42), and 23.3% (10/43), respectively. PJK rates among TC patients were significantly lower than NT (P = .01601). CONCLUSION Junctional tethers with crosslink significantly reduced the incidence of PJK and revisions for PJK among ASD patients treated with long-segment posterior instrumented fusions who achieved minimum 2-yr follow-up.
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Affiliation(s)
- Emily P Rabinovich
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - M Harrison Snyder
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Jesse J McClure
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Thomas J Buell
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA.,Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Justin S Smith
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
| | - Christopher I Shaffrey
- Department of Neurosurgery, Duke University Medical Center, Durham, North Carolina, USA.,Department of Orthopedic Surgery, Duke University Medical Center, Durham, North Carolina, USA
| | - Avery L Buchholz
- Department of Neurological Surgery, University of Virginia Health System, Charlottesville, Virginia, USA
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