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Rahmani R, Stegelmann SD, Andreshak T. S2 alar-iliac screws are superior to traditional iliac screws for spinopelvic fixation in adult spinal deformity: a systematic review and meta-analysis. Spine Deform 2024; 12:829-842. [PMID: 38427156 DOI: 10.1007/s43390-024-00834-x] [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: 11/29/2023] [Accepted: 01/20/2024] [Indexed: 03/02/2024]
Abstract
PURPOSE Spinopelvic fixation (SPF) using traditional iliac screws has provided biomechanical advantages compared to previous constructs, but common complications include screw prominence and wound complications. The newer S2 alar-iliac (S2AI) screw may provide a lower profile option with lower rates of complications and revisions for adult spinal deformity (ASD). The purpose of this study was to compare rates of complications and revision following SPF between S2AI and traditional iliac screws in patients with ASD. METHODS A PRISMA-compliant systematic literature review was conducted using Cochrane, Embase, and PubMed. Included studies reported primary data on adult patients undergoing S2AI screw fixation or traditional IS fixation for ASD. Primary outcomes of interest were rates of revision and complications, which included screw failure (fracture and loosening), symptomatic screw prominence, wound complications (dehiscence and infection), and L5-S1 pseudarthrosis. RESULTS Fifteen retrospective studies with a total of 1502 patients (iliac screws: 889 [59.2%]; S2AI screws: 613 [40.8%]) were included. Pooled analysis indicated that iliac screws had significantly higher odds of revision (17.1% vs 9.1%, OR = 2.45 [1.25-4.77]), symptomatic screw prominence (9.9% vs 2.2%, OR = 6.26 [2.75-14.27]), and wound complications (20.1% vs 4.4%, OR = 5.94 [1.55-22.79]). S2AI screws also led to a larger preoperative to postoperative decrease in pain (SMD = - 0.26, 95% CI = -0.50, - 0.011). CONCLUSION The findings from this review demonstrate higher rates of revision, symptomatic screw prominence, and wound complications with traditional iliac screws. Current data supports the use of S2AI screws specifically for ASD. PROSPERO ID CRD42022336515. LEVEL OF EVIDENCE III.
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Affiliation(s)
- Roman Rahmani
- Mercy Health St. Vincent Medical Center, Toledo, OH, USA
| | - Samuel D Stegelmann
- HCA Medical City Healthcare UNT-TCU GME (Denton), 3535 S Interstate 35, Denton, TX, 76210, USA.
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Qiao N, Villemure I, Wang Z, Petit Y, Aubin CE. Optimization of S2-alar-iliac screw (S2AI) fixation in adult spine deformity using a comprehensive genetic algorithm and finite element model personalized to patient geometry and bone mechanical properties. Spine Deform 2024; 12:595-602. [PMID: 38451404 DOI: 10.1007/s43390-024-00833-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 01/20/2024] [Indexed: 03/08/2024]
Abstract
PURPOSE To optimize the biomechanical performance of S2AI screw fixation using a genetic algorithm (GA) and patient-specific finite element analysis integrating bone mechanical properties. METHODS Patient-specific pelvic finite element models (FEM), including one normal and one osteoporotic model, were created from bi-planar multi-energy X-rays (BMEXs). The genetic algorithm (GA) optimized screw parameters based on bone mass quality (BM method) while a comparative optimization method maximized the screw corridor radius (GEO method). Biomechanical performance was evaluated through simulations, comparing both methods using pullout and toggle tests. RESULTS The optimal screw trajectory using the BM method was more lateral and caudal with insertion angles ranging from 49° to 66° (sagittal plane) and 29° to 35° (transverse plane). In comparison, the GEO method had ranges of 44° to 54° and 24° to 30° respectively. Pullout forces (PF) using the BM method ranged from 5 to 18.4 kN, which were 2.4 times higher than the GEO method (2.1-7.7 kN). Toggle loading generated failure forces between 0.8 and 10.1 kN (BM method) and 0.9-2.9 kN (GEO method). The bone mass surrounding the screw representing the fitness score and PF of the osteoporotic case were correlated (R2 > 0.8). CONCLUSION Our study proposed a patient-specific FEM to optimize the S2AI screw size and trajectory using a robust BM approach with GA. This approach considers surgical constraints and consistently improves fixation performance.
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Affiliation(s)
- Ningxin Qiao
- Institute of Biomedical Engineering, Polytechnique Montréal, PO Box 6079, Downtown station, Montreal, QC H3C 3A7, Canada
- Sainte-Justine University Hospital Center, Montreal, Canada
| | - Isabelle Villemure
- Institute of Biomedical Engineering, Polytechnique Montréal, PO Box 6079, Downtown station, Montreal, QC H3C 3A7, Canada
- Sainte-Justine University Hospital Center, Montreal, Canada
| | - Zhi Wang
- Centre Hospitalier de l'Université de Montréal, Montreal, Canada
- Department of Surgery, Faculty of Medicine, Université de Montréal, Montreal, Canada
| | - Yvan Petit
- Department of Mechanical Engineering, Ecole de Technologie Supérieure, Montreal, Canada
| | - Carl-Eric Aubin
- Institute of Biomedical Engineering, Polytechnique Montréal, PO Box 6079, Downtown station, Montreal, QC H3C 3A7, Canada.
- Sainte-Justine University Hospital Center, Montreal, Canada.
- Department of Surgery, Faculty of Medicine, Université de Montréal, Montreal, Canada.
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Chanbour H, Roth SG, Chen JW, Uppuganti S, Nyman JS, Ali MA, Bonfield CM, Abtahi AM, Stephens BF, Zuckerman SL. Do Iliac Screws Placed Close to the Sciatic Notch Have Greater Pullout Strength? Oper Neurosurg (Hagerstown) 2024:01787389-990000000-01136. [PMID: 38651901 DOI: 10.1227/ons.0000000000001159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 02/24/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND AND OBJECTIVES Optimal iliac screw position in relation to the sciatic notch remains unknown. In 12 cadavers undergoing S2 alar-iliac (S2AI) screw placement, we tested the pullout strength of screws placed in proximity to the sciatic notch (≤5 mm) vs farther away from the sciatic notch (>5 mm). METHODS A biomechanical, cadaver-based study was performed on 12 cadavers undergoing bilateral S2AI screw insertion. The position of the S2AI screw regarding the sciatic notch was dichotomized as ≤5 mm from the sciatic notch on the right side and >5 mm on the left side, confirmed using c-arm fluoroscopy. The primary outcome was the pullout strength of the screw (N). Secondary outcomes were stiffness (N/mm), yield force (N), and work to failure (N mm). Ischial tuberosity was embedded into polymethyl methacrylate and secured to a custom 3-axis vise grip mounted to a 14.5-kN load cell. Pullout testing was performed at 5 mm/min. Force and displacement data were collected at 100 Hz and evaluated using MATLAB. The Mann-Whitney test was performed. RESULTS Of 24 S2AI screws, 3 screws could not be tested because of cement-bone interface failure. A positive though nonsignificant trend of screw pullout strength was found for screws close to the notch compared with those farther from the notch (861.8 ± 340.7 vs 778.7 ± 350.8 N, P = .859). Similarly, screws close to the notch demonstrated a higher trend of stiffness (149.4 ± 145.4 vs 111.34 ± 128.2 N/mm, P = .320) and force to yield (806.9 ± 352.0 vs 618.6 ± 342.9 N, P = .455). Conversely, screws farther from the notch had a higher but similarly nonsignificant area under the force-displacement curve (10 867.0 ± 9565.0 vs 14 196.6 ± 9578.3 N mm, P = .455), which might be due to excess sheer/translation force that could not be reliably quantified. CONCLUSION Although placing S2AI screws ≤5 mm of the sciatic notch provided stronger fixation in 3 of 4 biomechanical testing categories, these results were not statistically significant. Therefore, placing S2AI screws ≤5 mm of the sciatic notch did not provide stronger fixation.
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Affiliation(s)
- Hani Chanbour
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Steven G Roth
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jeffrey W Chen
- Department of Neurological Surgery, Baylor College of Medicine, Houston, Texas, USA
| | - Sasidhar Uppuganti
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jeffry S Nyman
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Biomedical Engineering, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Mir Amaan Ali
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Christopher M Bonfield
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Amir M Abtahi
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Byron F Stephens
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Scott L Zuckerman
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Orthopedic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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Odland K, Chanbour H, Zuckerman SL, Polly DW. Spinopelvic fixation failure in the adult spinal deformity population: systematic review and meta-analysis. 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 2024:10.1007/s00586-024-08241-6. [PMID: 38619634 DOI: 10.1007/s00586-024-08241-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 03/13/2024] [Accepted: 03/26/2024] [Indexed: 04/16/2024]
Abstract
INTRODUCTION Despite modern fixation techniques, spinopelvic fixation failure (SPFF) after adult spinal deformity (ASD) surgery ranges from 4.5 to 38.0%, with approximately 50% requiring reoperation. Compared to other well-studied complications after ASD surgery, less is known about the incidence and predictors of SPFF. AIMS/OBJECTIVES Given the high rates of SPFF and reoperation needed to treat it, the purpose of this systematic review and meta-analysis was to report the incidence and failure mechanisms of SPF after ASD surgery. MATERIALS/METHODS The literature search was executed across four databases: Medline via PubMed and Ovid, SPORTDiscus via EBSCO, Cochrane Library via Wiley, and Scopus. Study inclusion criteria were patients undergoing ASD surgery with spinopelvic instrumentation, report rates of SPFF and type of failure mechanism, patients over 18 years of age, minimum 1-year follow-up, and cohort or case-control studies. From each study, we collected general demographic information (age, gender, and body mass index), primary/revision, type of ASD, and mode of failure (screw loosening, rod breakage, pseudarthrosis, screw failure, SI joint pain, screw protrusion, set plug dislodgment, and sacral fracture) and recorded the overall rate of SPF as well as failure rate for each type. For the assessment of failure rate, we required a minimum of 12 months follow-up with radiographic assessment. RESULTS Of 206 studies queried, 14 met inclusion criteria comprising 3570 ASD patients who underwent ASD surgery with pelvic instrumentation (mean age 65.5 ± 3.6 years). The mean SPFF rate was 22.1% (range 3-41%). Stratification for type of failure resulted in a mean SPFF rate of 23.3% for the pseudarthrosis group; 16.5% for the rod fracture group; 13.5% for the iliac screw loosening group; 7.3% for the SIJ pain group; 6.1% for the iliac screw group; 3.6% for the set plug dislodgement group; 1.1% for the sacral fracture group; and 1% for the iliac screw prominence group. CONCLUSION The aggregate rate of SPFF after ASD surgery is 22.1%. The most common mechanisms of failure were pseudarthrosis, rod fracture, and iliac screw loosening. Studies of SPFF remain heterogeneous, and a consistent definition of what constitutes SPFF is needed. This study may enable surgeons to provide patient specific constructs with pelvic fixation constructs to minimize this risk of failure.
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Affiliation(s)
- Kari Odland
- Department of Orthopedic Surgery, University of Minnesota, 2450 Riverside Avenue South, Suite R200, Minneapolis, MN, 55454, USA.
| | - Hani Chanbour
- Department of Neurological Surgery, Vanderbilt University, Nashville, TN, 37204, USA
| | - Scott L Zuckerman
- Department of Neurological Surgery, Vanderbilt University, Nashville, TN, 37204, USA
| | - David W Polly
- Department of Orthopedic Surgery, University of Minnesota, 2450 Riverside Avenue South, Suite R200, Minneapolis, MN, 55454, USA
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Shin HK, Park JH, Jeon SR, Roh SW, Jo DJ, Hyun SJ, Cho YJ. Sacropelvic Fixation for Adult Deformity Surgery Comparing Iliac Screw and Sacral 2 Alar-Iliac Screw Fixation: Systematic Review and Updated Meta-Analysis. Neurospine 2023; 20:1469-1476. [PMID: 38171313 PMCID: PMC10762417 DOI: 10.14245/ns.2346654.327] [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: 06/13/2023] [Revised: 08/04/2023] [Accepted: 08/09/2023] [Indexed: 01/05/2024] Open
Abstract
OBJECTIVE Two commonly used techniques for spinopelvic fixation in adult deformity surgery are iliac screw (IS) and sacral 2 alar-iliac screw (S2AI) fixations. In this article, we systematically meta-analyzed the complications of sacropelvic fixation for adult deformity surgery comparing IS and S2AI. METHODS The PubMed, Embase, Web of Science, and Cochrane clinical trial databases were systematically searched until March 29, 2023. The proportion of postoperative complications, including implant failure, revision, screw prominence, and wound complications after sacropelvic fixation, were pooled with a random-effects model. Subgroup analyses for the method of sacropelvic fixation were conducted. RESULTS Ten studies with a total of 1,931 patients (IS, 925 patients; S2AI, 1,006 patients) were included. The pooled proportion of implant failure was not statistically different between the IS and S2AI groups (21.9% and 18.9%, respectively) (p = 0.59). However, revision was higher in the IS group (21.0%) than that in the S2AI group (8.5%) (p = 0.02). Additionally, screw prominence was higher in the IS group (9.6%) than that in the S2AI group (0.0%) (p < 0.01), and wound complication was also higher in the IS group (31.7%) than that in the S2AI group (3.9%) (p < 0.01). CONCLUSION IS and S2AI fixations showed that both techniques had similar outcomes in terms of implant failure. However, S2AI was revealed to have better outcomes than IS in terms of revision, screw prominence, and wound complications.
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Affiliation(s)
- Hong Kyung Shin
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Jin Hoon Park
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sang Ryong Jeon
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Sung Woo Roh
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Dae Jean Jo
- Department of Neurosurgery, Kyung Hee University Hospital at Gangdong, Seoul, Korea
| | - Seung-Jae Hyun
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Yong-Jae Cho
- Department of Neurosurgery, Ewha Womans University School of Medicine, Seoul, Korea
| | - for the Korean Spinal Deformity Society (KSDS)
- Department of Neurological Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
- Department of Neurosurgery, Kyung Hee University Hospital at Gangdong, Seoul, Korea
- Department of Neurosurgery, Spine Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
- Department of Neurosurgery, Ewha Womans University School of Medicine, Seoul, Korea
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Qiao N, Villemure I, Aubin CE. A novel method for assigning bone material properties to a comprehensive patient-specific pelvic finite element model using biplanar multi-energy radiographs. Comput Methods Biomech Biomed Engin 2023:1-12. [PMID: 37975562 DOI: 10.1080/10255842.2023.2280764] [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: 08/11/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023]
Abstract
The increasing prevalence of adult spinal deformity requires long spino-pelvic instrumentation, but pelvic fixation faces challenges due to distal forces and reduced bone quality. Bi-planar multi-energy X-rays (BMEX) were used to develop a patient-specific finite element model (FEM) for evaluating pelvic fixation. Calibration involved 10 patients, and an 81-year-old female test case was used for FEM customization and pullout simulation validation. Calibration yielded a root mean square error of 74.7 mg/cm3 for HU. The simulation accurately replicated the experimental pullout test with a force of 565 N, highlighting the method's potential for optimizing biomechanical performance for pelvic fixation.
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Affiliation(s)
- Ningxin Qiao
- Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Canada
- Sainte-Justine University Hospital Center, Montreal, Canada
| | - Isabelle Villemure
- Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Canada
- Sainte-Justine University Hospital Center, Montreal, Canada
| | - Carl-Eric Aubin
- Institute of Biomedical Engineering, Polytechnique Montreal, Montreal, Canada
- Sainte-Justine University Hospital Center, Montreal, Canada
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Zuckerman SL, Cher D, Capobianco R, Sciubba D, Polly DW. Estimating the Cost of Spinopelvic Complications After Adult Spinal Deformity Surgery. CLINICOECONOMICS AND OUTCOMES RESEARCH 2023; 15:765-772. [PMID: 37964981 PMCID: PMC10642569 DOI: 10.2147/ceor.s437202] [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: 09/20/2023] [Accepted: 11/01/2023] [Indexed: 11/16/2023] Open
Abstract
Objective Reoperations for spinopelvic failure after adult spinal deformity (ASD) surgery are common. We sought to determine the added costs of ASD surgery attributable to reoperations for spinopelvic construct failures. Methods We constructed a Markov process model to calculate the expected discounted 5-year costs of spinopelvic construct failures after ASD surgery. The Nationwide Inpatient Sample (NIS) was queried to estimate the number of ASD surgeries. Model inputs were based on literature review and expert opinion. ASD surgery was defined as thoracolumbar fusion of 4 or more levels with pelvic fixation. The following pelvic fixation failures were included: 1) rod fracture or pseudarthrosis from L4-S1, 2) iliac screw failure or set plug dislodgment, 3) iliac screw prominence, and 4) sacroiliac (SI) joint pain. The number of patients undergoing ASD surgery annually in the US was determined using a commercial claims database. Results The net present value 5-year cost per patient for spinopelvic complications was $35,265, equal to 29% of index surgery costs. Given an estimated 27,580 cases annually in the US, the additional cost to address spinopelvic complications reach nearly $1 billion over 5-years. A sensitivity analysis showed that these costs were most sensitive to the rate of rod fracture/pseudarthrosis, iliac screw prominence, and reoperation. Conclusion A conservative estimate of the cost of spinopelvic failures after ASD surgery is substantial, nearly $1 billion over 5-years. We propose a method of capturing spinopelvic fixation failures for use in future clinical studies and cost analyses.
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Affiliation(s)
- Scott L Zuckerman
- Department of Neurological Surgery, Vanderbilt University Medical Center, Nashville, TN, USA
| | | | | | - Daniel Sciubba
- Department of Neurosurgery, Zucker School of Medicine at Hofstra, Long Island Jewish Medical Center and North Shore University Hospital, Northwell Health, Manhasset, NY, USA
| | - David W Polly
- Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, USA
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Yang H, Pan A, Hai Y, Cheng F, Ding H, Liu Y. Biomechanical evaluation of multiple pelvic screws and multirod construct for the augmentation of lumbosacral junction in long spinal fusion surgery. Front Bioeng Biotechnol 2023; 11:1148342. [PMID: 36998811 PMCID: PMC10043192 DOI: 10.3389/fbioe.2023.1148342] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/06/2023] [Indexed: 03/15/2023] Open
Abstract
Background: Posterior long spinal fusion was the common procedure for adult spinal deformity (ASD). Although the application of sacropelvic fixation (SPF), the incidence of pseudoarthrosis and implant failure is still high in long spinal fusion extending to lumbosacral junction (LSJ). To address these mechanical complications, advanced SPF technique by multiple pelvic screws or multirod construct has been recommended. This was the first study to compare the biomechanical performance of combining multiple pelvic screws and multirod construct to other advanced SPF constructs for the augmentation of LSJ in long spinal fusion surgery through finite element (FE) analysis.Methods: An intact lumbopelvic FE model based on computed tomography images of a healthy adult male volunteer was constructed and validated. The intact model was modified to develop five instrumented models, all of which had bilateral pedicle screw (PS) fixation from L1 to S1 with posterior lumbar interbody fusion and different SPF constructs, including No-SPF, bilateral single S2-alar-iliac (S2AI) screw and single rod (SS-SR), bilateral multiple S2AI screws and single rod (MS-SR), bilateral single S2AI screw and multiple rods (SS-MR), and bilateral multiple S2AI screws and multiple rods (MS-MR). The range of motion (ROM) and stress on instrumentation, cages, sacrum, and S1 superior endplate (SEP) in flexion (FL), extension (EX), lateral bending (LB), and axial rotation (AR) were compared among models.Results: Compared with intact model and No-SPF, the ROM of global lumbopelvis, LSJ, and sacroiliac joint (SIJ) was decreased in SS-SR, MS-SR, SS-MR, and MS-MR in all directions. Compared with SS-SR, the ROM of global lumbopelvis and LSJ of MS-SR, SS-MR, and MS-MR further decreased, while the ROM of SIJ was only decreased in MS-SR and MS-MR. The stress on instrumentation, cages, S1-SEP, and sacrum decreased in SS-SR, compared with no-SPF. Compared with SS-SR, the stress in EX and AR further decreased in SS-MR and MS-SR. The most significantly decreased ROM and stress were observed in MS-MR.Conclusion: Both multiple pelvic screws and multirod construct could increase the mechanical stability of LSJ and reduce stress on instrumentation, cages, S1-SEP, and sacrum. The MS-MR construct was the most adequate to reduce the risk of lumbosacral pseudarthrosis, implant failure, and sacrum fracture. This study may provide surgeons with important evidence for the application of MS-MR construct in the clinical settings.
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Affiliation(s)
| | | | - Yong Hai
- *Correspondence: Yong Hai, ; Yuzeng Liu,
| | | | | | - Yuzeng Liu
- *Correspondence: Yong Hai, ; Yuzeng Liu,
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Lee NJ, Marciano G, Puvanesarajah V, Park PJ, Clifton WE, Kwan K, Morrissette CR, Williams JL, Fields M, Hassan FM, Angevine PD, Mandigo CE, Lombardi JM, Sardar ZM, Lehman RA, Lenke LG. Incidence, mechanism, and protective strategies for 2-year pelvic fixation failure after adult spinal deformity surgery with a minimum six-level fusion. J Neurosurg Spine 2023; 38:208-216. [PMID: 36242579 DOI: 10.3171/2022.8.spine22755] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 08/29/2022] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The purpose of this study was to determine the incidence, mechanism, and potential protective strategies for pelvic fixation failure (PFF) within 2 years after adult spinal deformity (ASD) surgery. METHODS Data for ASD patients (age ≥ 18 years, minimum of six instrumented levels) with pelvic fixation (S2-alar-iliac [S2AI] and/or iliac screws) with a minimum 2-year follow-up were consecutively collected (2015-2019). Patients with prior pelvic fixation were excluded. PFF was defined as any revision to pelvic screws, which may include broken rods across the lumbosacral junction requiring revision to pelvic screws, pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws, a broken or loose pelvic screw, or sacral/iliac fracture. Patient information including demographic data and health history (age, sex, BMI, smoking status, American Society of Anesthesiologists score, osteoporosis), operative (total instrumented levels [TIL], three-column osteotomy [3CO], interbody fusion), screw (iliac, S2AI, length, diameter), rod (diameter, kickstand), rod pattern (number crossing lumbopelvic junction, lowest instrumented vertebra [LIV] of accessory rod[s], lateral connectors, dual-headed screws), and pre- and postradiographic (lumbar lordosis, pelvic incidence, pelvic tilt, major Cobb angle, lumbosacral fractional curve, C7 coronal vertical axis [CVA], T1 pelvic angle, C7 sagittal vertical axis) parameters was collected. All rods across the lumbosacral junction were cobalt-chrome. All iliac and S2AI screws were closed-headed tulips. Both univariate and multivariate analyses were performed to determine risk factors for PFF. RESULTS Of 253 patients (mean age 58.9 years, mean TIL 13.6, 3CO 15.8%, L5-S1 interbody 74.7%, mean pelvic screw diameter/length 8.6/87 mm), the 2-year failure rate was 4.3% (n = 11). The mechanisms of failure included broken rods across the lumbosacral junction (n = 4), pseudarthrosis across the lumbosacral junction requiring revision to pelvic screws (n = 3), broken pelvic screw (n = 1), loose pelvic screw (n = 1), sacral/iliac fracture (n = 1), and painful/prominent pelvic screw (n = 1). A higher number of rods crossing the lumbopelvic junction (mean 3.8 no failure vs 2.9 failure, p = 0.009) and accessory rod LIV to S2/ilium (no failure 54.2% vs failure 18.2%, p = 0.003) were protective for failure. Multivariate analysis demonstrated that accessory rod LIV to S2/ilium versus S1 (OR 0.2, p = 0.004) and number of rods crossing the lumbar to pelvis (OR 0.15, p = 0.002) were protective, while worse postoperative CVA (OR 1.5, p = 0.028) was an independent risk factor for failure. CONCLUSIONS The 2-year PFF rate was low relative to what is reported in the literature, despite patients undergoing long fusion constructs for ASD. The number of rods crossing the lumbopelvic junction and accessory rod LIV to S2/ilium relative to S1 alone likely increase construct stiffness. Residual postoperative coronal malalignment should be avoided to reduce PFF.
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Computed Tomography-Based Prediction of Lumbar Pedicle Screw Loosening. BIOMED RESEARCH INTERNATIONAL 2023; 2023:8084597. [PMID: 36743516 PMCID: PMC9891825 DOI: 10.1155/2023/8084597] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 01/03/2023] [Accepted: 01/16/2023] [Indexed: 01/27/2023]
Abstract
Objective Pedicle screw loosening is one of the main complications after pedicle screw fixation. However, there are few reliable measures for prediction of screw loosening. The current study was carried out to find an effective method to use preoperative CT scanning as a predictor of screw loosening in the elderly patients and provide guidance for preoperative surgical planning. Methods Patients who were treated with lumbar pedicle screw fixation procedure in our department for degenerative lumbar disorders between January 2015 and January 2021 were retrospectively included in the current study. CT scan attenuation of each vertebra was measured with Hounsfield units (HU). Screw loosening was determined in postoperatively X-ray tests. One-way analysis of variance (ANOVA) and receiver operating characteristic (ROC) curve analysis were carried out with IBMSPSS 24.00 software. Results Screw loosening was observed in 44 of 215 patients (124 male, 91 female, average age 58.4 ± 7.6 years) during a mean follow-up time of 19.0 ± 11.2 months (range 12-32 months). No significant differences were found among the patients concerning patient gender, BMI, habit of smoking, and whether or not the patient had diabetes or suffered from spondylolisthesis (P > 0.05). The average HU value of lumbar vertebra was 122.4 ± 32.8 HU in the screw loosening group and 142.4 ± 38.2 HU in the control group, and the difference was significant (P < 0.01). ROC curve analysis revealed that the average HU value of L1-L5 has a relatively larger area under the curve (AUC) of 0.689 (95% CI: 0.605-0.773). With the sensitivity of 68% and specificity of 57%, a HU cut-off value of ≤124 HU is a plausible cut-off point to predict screw loosening. Conclusions A prospective CT scan HU value-based prediction can be used to decide whether or not to use screw augmentation methods. A cut-off L1-L5 average HU value of 124 HU can be used as an independent risk factor for screw loosening in instrumented lumbar vertebra. More predictive indexes should be involved to achieve higher sensitivity and specificity in future clinical practice.
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