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Turbucz M, Pokorni AJ, Hajnal B, Koch K, Szoverfi Z, Varga PP, Lazary A, Eltes PE. The biomechanical effect of lumbopelvic distance reduction on reconstruction after total sacrectomy: a comparative finite element analysis of four techniques. Spine J 2024; 24:1981-1992. [PMID: 38688331 DOI: 10.1016/j.spinee.2024.04.024] [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: 12/20/2023] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 05/02/2024]
Abstract
BACKGROUND CONTEXT Following total sacrectomy, lumbopelvic reconstruction is essential to restore continuity between the lumbar spine and pelvis. However, to achieve long-term clinical stability, bony fusion between the lumbar spine and the pelvic ring is crucial. Reduction of the lumbopelvic distance can promote successful bony fusion. Although many lumbopelvic reconstruction techniques (LPRTs) have been previously analyzed, the biomechanical effect of lumbopelvic distance reduction (LPDR) has not been investigated yet. PURPOSE To evaluate and compare the biomechanical characteristics of four different LPRTs while considering the effect of LPDR. STUDY DESIGN/SETTING A comparative finite element (FE) study. METHODS The FE models following total sacrectomy were developed to analyze four different LPRTs, with and without LPDR. The closed-loop reconstruction (CLR), the sacral-rod reconstruction (SRR), the four-rod reconstruction (FRR), and the improved compound reconstruction (ICR) techniques were analyzed in flexion, extension, lateral bending, and axial rotation. Lumbopelvic stability was assessed through the shift-down displacement and the relative sagittal rotation of L5, while implant safety was evaluated based on the stress state at the bone-implant interface and within the rods. RESULTS Regardless of LPDR, both the shift-down displacement and relative sagittal rotation of L5 consistently ranked the LPRTs as ICR CONCLUSIONS LPDR significantly improved both lumbopelvic stability and implant safety in all reconstruction techniques after total sacrectomy. LPDR reduced the shift-down displacement of L5, the relative sagittal rotation of L5, and the stress values at the bone-implant interface. Furthermore, in the ICR and SRR techniques, LPDR decreased the peak stress values within the rods. All four investigated LPRTs demonstrated suitability for lumbopelvic reconstruction, with the ICR technique exhibiting the highest lumbopelvic stiffness. CLINICAL SIGNIFICANCE LPDR creates a biomechanically advantageous environment following total sacrectomy; therefore, it has the potential to impact the design of custom-made 3D-printed or traditional LPRTs. However, to confirm the findings of the current FE study, long-term clinical trials are recommended.
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Affiliation(s)
- Mate Turbucz
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Agoston Jakab Pokorni
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Benjamin Hajnal
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Kristof Koch
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Zsolt Szoverfi
- National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Peter Pal Varga
- National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Aron Lazary
- National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Üllői Str. 78/b, Budapest, Hungary
| | - Peter Endre Eltes
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Üllői Str. 78/b, Budapest, Hungary.
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Joukar A, Mehta J, Goel VK, Marks DS. Biomechanical Analysis of the Tuning Fork Plate Versus Dual Pelvic Screws in a Sacrectomy Model: A Finite Element Study. Global Spine J 2022; 12:1495-1502. [PMID: 33517788 PMCID: PMC9393982 DOI: 10.1177/2192568220983792] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
STUDY DESIGN To evaluate the mechanical effectiveness of "tuning fork" plate fixation system by comparing with dual iliac screw fixation under different spinal motion through finite element analysis (FEA). OBJECTIVE Lumbosacral deficiencies occur from birth defects or following destruction by tumors. The objective of this study was to evaluate the mechanical effectiveness of the tuning fork plate compared to dual iliac screw system which is the gold standard fixation in treating lumbosacral deficiencies. This is an innovative fixation device for treating lumbosacral deficiencies. METHODS The deficiency model was prepared using a previously developed and validated finite element T10-pelvis model. To create the lumbo-sacral deficiency the segments between L3 and sacrum were removed from the model. The model was then instrumented from T10 to L2 segments and the ilium using either the tuning fork plate or a dual iliac screw construct. With the ilium fixed, the T10 vertebrae was subjected to 10 Nm moment and 400 N follower load to simulate spinal motions. Range of motion (ROM) of spine and stresses on the instrumentation were calculated for 2 fixation devices and compared with each other. RESULTS The 2 fixation systems demonstrate a comparable motion reduction in all loading modes. Stress values were higher in the dual iliac screw constructs compared with the tuning fork plate fixation system. The factor of safety of the tuning fork plate device was higher than the dual iliac screw fixation by 50%. CONCLUSIONS Both fixation devices had similar performance in motion reduction at spine levels. However, based on predicted implant stresses there were less chances of implant failure in the fork plate fixation, compared to the dual iliac screw system.
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Affiliation(s)
- Amin Joukar
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA
| | - Jwalant Mehta
- Royal Orthopaedic Hospital, Birmingham, United Kingdom,Jwalant Mehta, Royal Orthopaedic Hospital, Bristol Road South, Birmingham, B31 2AP, United Kingdom.
| | - Vijay K. Goel
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA
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Wellings EP, Houdek MT, Owen AR, Bakri K, Yaszemski MJ, Sim FH, Moran SL, Rose PS. Comparison of free vascularized fibular flaps and allograft fibular strut grafts to supplement spinopelvic reconstruction for sacral malignancies. Bone Joint J 2021; 103-B:1414-1420. [PMID: 34334037 DOI: 10.1302/0301-620x.103b8.bjj-2020-2302.r1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AIMS Orthopaedic and reconstructive surgeons are faced with large defects after the resection of malignant tumours of the sacrum. Spinopelvic reconstruction is advocated for resections above the level of the S1 neural foramina or involving the sacroiliac joint. Fixation may be augmented with either free vascularized fibular flaps (FVFs) or allograft fibular struts (AFSs) in a cathedral style. However, there are no studies comparing these reconstructive techniques. METHODS We reviewed 44 patients (23 female, 21 male) with a mean age of 40 years (SD 17), who underwent en bloc sacrectomy for a malignant tumour of the sacrum with a reconstruction using a total (n = 20), subtotal (n = 2), or hemicathedral (n = 25) technique. The reconstructions were supplemented with a FVF in 25 patients (57%) and an AFS in 19 patients (43%). The mean length of the strut graft was 13 cm (SD 4). The mean follow-up was seven years (SD 5). RESULTS There was no difference in the mean age, sex, length of graft, size of the tumour, or the proportion of patients with a history of treatment with radiotherapy in the two groups. Reconstruction using an AFS was associated with nonunion (odds ratio 7.464 (95% confidence interval (CI) 1.77 to 31.36); p = 0.007) and a significantly longer mean time to union (12 months (SD 3) vs eight (SD 3); p = 0.001) compared with a reconstruction using a FVF. Revision for a pseudoarthrosis was more likely to occur in the AFS group compared with the FVF group (hazard ratio 3.84 (95% CI 0.74 to 19.80); p = 0.109); however, this was not significant. Following the procedure, 32 patients (78%) were mobile with a mean Musculoskeletal Tumor Society Score 93 of 52% (SD 24%). There was a significantly higher mean score in patients reconstructed with a FVF compared with an AFS (62% vs 42%; p = 0.003). CONCLUSION Supplementation of spinopelvic reconstruction with a FVF was associated with a shorter time to union and a trend towards a reduced risk of hardware failure secondary to nonunion compared with reconstruction using an AFS. Spinopelvic fixation supplemented with a FVF is our preferred technique for reconstruction following resection of a sacral tumour. Cite this article: Bone Joint J 2021;103-B(8):1414-1420.
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Affiliation(s)
| | - Matthew T Houdek
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Aaron R Owen
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Karim Bakri
- Division of Plastic and Reconstructive Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Franklin H Sim
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Steven L Moran
- Division of Plastic and Reconstructive Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Peter S Rose
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
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Cheng BC, Swink I, Yusufbekov R, Birgelen M, Ferrara L, Lewandrowski KU, Coric D. Current Concepts of Contemporary Expandable Lumbar Interbody Fusion Cage Designs, Part 1: An Editorial on Their Biomechanical Characteristics. Int J Spine Surg 2020; 14:S63-S67. [PMID: 33122179 DOI: 10.14444/7128] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND Bidirectional expandable designs for lumbar interbody fusion cages are the latest iteration of expandable spacers employed to address some of the common problems inherent to static interbody fusion cages. OBJECTIVE To describe the rationales for contemporary bidirectional, multimaterial expandable lumbar interbody fusion cage designs to achieve in situ expansion for maximum anterior column support while decreasing insertion size during minimal-access surgeries. METHODS The authors summarize the current concepts behind expandable spinal fusion open architecture cage designs focusing on advanced minimally invasive spinal surgery techniques, such as endoscopy. A cage capable of bidirectional expansion in both height and width to address constrained surgical access problems was of particular interest to the authors while they analyzed the relationship between implant material stiffness and geometric design regarding the risk of subsidence and reduced graft loading. CONCLUSIONS Biomechanical advantages of new bidirectional, multimaterial expandable interbody fusion cages allow insertion through minimal surgical access and combine the advantages of proven device configurations and advanced material selection. The final construct stiffness is sufficient to provide immediate anterior column support while accommodating reduced sizes required for minimally invasive surgery applications. LEVEL OF EVIDENCE 7.
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Affiliation(s)
- Boyle C Cheng
- Department of Neurosurgery, Allegheny Health Network, Pittsburgh, Pennsylvania
| | - Isaac Swink
- Department of Neurosurgery, Allegheny Health Network, Pittsburgh, Pennsylvania
| | | | - Michele Birgelen
- Department of Neurosurgery, Allegheny Health Network, Pittsburgh, Pennsylvania
| | - Lisa Ferrara
- OrthoKinetic Technologies LLC, Southport, North Carolina
| | - Kai-Uwe Lewandrowski
- Center for Advanced Spine Care of Southern Arizona and Surgical Institute of Tucson, Arizona
| | - Domagoj Coric
- Carolina Neurosurgery & Spine Associates, Charlotte, North Carolina.,Atrium Musculoskeletal Institute, Charlotte, North Carolina
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Biomechanical comparison of a 3D-printed sacrum prosthesis versus rod-screw systems for reconstruction after total sacrectomy: A finite element analysis. Clin Biomech (Bristol, Avon) 2019; 70:203-208. [PMID: 31655451 DOI: 10.1016/j.clinbiomech.2019.10.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 10/11/2019] [Accepted: 10/17/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Reconstruction after total sacrectomy is a difficult problem in the field of orthopedic oncology. Current reconstruction methods have not completely solved the problems associated with instrumentation failure. The purpose of this study was to evaluate the biomechanical properties of a 3D-printed total sacrum prosthesis and to conduct biomechanical comparisons between the total sacrum prosthesis and rod-screw systems for lumbosacral reconstruction after total sacrectomy. METHODS Three types of reconstruction were explored, and corresponding finite element models were simulated: four-rod reconstruction, four-rod plus anterior column reconstruction, and 3D-printed total sacrum prosthesis reconstruction. A vertical load of 600 N was applied to the L4 vertebra, and the bilateral acetabula were set as the boundary with six degrees of freedom fixed, simulating the bipedal standing position. FINDINGS The order of the reconstructions according to decreasing maximum von Mises stress was as follows: four-rod reconstruction > four-rod plus anterior column reconstruction >3D-printed total sacrum prosthesis reconstruction. The order of reconstructions according to decreasing L5 shift-down displacement was as follows: four-rod reconstruction >3D-printed total sacrum prosthesis reconstruction > four-rod plus anterior column reconstruction. INTERPRETATION Compared with the rod-screw systems, the total sacrum prosthesis reconstruction has the biomechanical advantages of a more uniform stress distribution, a lower peak stress and better stability and can thus serve as an alternative choice for reconstruction after total sacrectomy.
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Huang S, Ji T, Guo W. [Development and current situation of reconstruction methods following total sacrectomy]. ZHONGGUO XIU FU CHONG JIAN WAI KE ZA ZHI = ZHONGGUO XIUFU CHONGJIAN WAIKE ZAZHI = CHINESE JOURNAL OF REPARATIVE AND RECONSTRUCTIVE SURGERY 2018; 32:513-518. [PMID: 29806335 PMCID: PMC8430014 DOI: 10.7507/1002-1892.201712054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 04/02/2018] [Indexed: 11/03/2022]
Abstract
Objective To review the development of the reconstruction methods following total sacrectomy, and to provide reference for finding a better reconstruction method following total sacrectomy. Methods The case reports and biomechanical and finite element studies of reconstruction following total sacrectomy at home and abroad were searched. Development and current situation were summarized. Results After developing for nearly 30 years, great progress has been made in the reconstruction concept and fixation techniques. The fixation methods can be summarized as the following three strategies: spinopelvic fixation (SPF), posterior pelvic ring fixation (PPRF), and anterior spinal column fixation (ASCF). SPF has undergone technical progress from intrapelvic rod and hook constructs to pedicle and iliac screw-rod systems. PPRF and ASCF could improve the stability of the reconstruction system. Conclusion Reconstruction following total sacrectomy remains a challenge. Reconstruction combining SPF, PPRF, and ASCF is the developmental direction to achieve mechanical stability. How to gain biological fixation to improve the long-term stability is an urgent problem to be solved.
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Affiliation(s)
- Siyi Huang
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, 100044, P.R.China
| | - Tao Ji
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, 100044, P.R.China
| | - Wei Guo
- Musculoskeletal Tumor Center, Peking University People's Hospital, Beijing, 100044,
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The primary stability of different implants for intra-articular calcaneal fractures: an in vitro study. Biomed Eng Online 2018; 17:50. [PMID: 29716591 PMCID: PMC5930824 DOI: 10.1186/s12938-018-0484-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 04/23/2018] [Indexed: 11/25/2022] Open
Abstract
Background Calcaneal fractures account for around 2% of all fractures and most of them are intra-articular fractures. Many implants have been used in the fixation of calcaneal fractures, but their biomechanical stability has not yet been well investigated. The aim of this study was to compare the primary stability of four fixations of calcaneal fracture. Methods Eight cadaveric calcaneus samples were used to simulate the Sanders’ types III fracture pattern and fixed through four different implants, namely, K-wires, cannulated screws (CS), absorbable screws (AS), and plate-screw system (PSS). Each specimen was then placed into a custom-made jig and was loaded through a material testing machine to simulate the physiological condition. The primary stability was measured in the vertical direction as the stiffness and anterior–posterior direction as the calcaneocuboid force. One-way analysis of variance was used for data analysis. Results The results showed the highest stiffness of 634 (383–891; SD 226) N/mm in the intact model. It was significantly higher than the models fixed with K-wires, CS or PSS. There was no significant difference in vertical stiffness between fractures fixed with AS and the intact model or other fixed models. The intact model showed the lowest calcaneocuboid force of 153 (120–218; SD 39) N, while the fractures fixed with AS showed the greatest force of 242 (146–398; SD 84) N. The significance was only detected between these two models. Conclusions The global stiffness was similar when the calcaneal fractures were fixed by K-wires, CS and PSS. The stability of the AS fixation differed along both the vertical and anterior–posterior directions, and was greatly influenced by the bone quality. AS for fracture fixation should be designed with greater strength and pull-out resistance.
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Macki M, De la Garza-Ramos R, Murgatroyd AA, Mullinix KP, Sun X, Cunningham BW, McCutcheon BA, Bydon M, Gokaslan ZL. Comprehensive biomechanical analysis of three reconstruction techniques following total sacrectomy: an in vitro human cadaveric model. J Neurosurg Spine 2017; 27:570-577. [DOI: 10.3171/2017.2.spine161128] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVEAggressive sacral tumors often require en bloc resection and lumbopelvic reconstruction. Instrumentation failure and pseudarthrosis remain a clinical concern to be addressed. The objective in this study was to compare the biomechanical stability of 3 distinct techniques for sacral reconstruction in vitro.METHODSIn a human cadaveric model study, 8 intact human lumbopelvic specimens (L2–pelvis) were tested for flexion-extension range of motion (ROM), lateral bending, and axial rotation with a custom-designed 6-df spine simulator as well as axial compression stiffness with the MTS 858 Bionix Test System. Biomechanical testing followed this sequence: 1) intact spine; 2) sacrectomy (no testing); 3) Model 1 (L3–5 transpedicular instrumentation plus spinal rods anchored to iliac screws); 4) Model 2 (addition of transiliac rod); and 5) Model 3 (removal of transiliac rod; addition of 2 spinal rods and 2 S-2 screws). Range of motion was measured at L4–5, L5–S1/cross-link, L5–right ilium, and L5–left ilium.RESULTSFlexion-extension ROM of the intact specimen at L4–5 (6.34° ± 2.57°) was significantly greater than in Model 1 (1.54° ± 0.94°), Model 2 (1.51° ± 1.01°), and Model 3 (0.72° ± 0.62°) (p < 0.001). Flexion-extension at both the L5–right ilium (2.95° ± 1.27°) and the L5–left ilium (2.87° ± 1.40°) for Model 3 was significantly less than the other 3 cohorts at the same level (p = 0.005 and p = 0.012, respectively). Compared with the intact condition, all 3 reconstruction groups statistically significantly decreased lateral bending ROM at all measured points. Axial rotation ROM at L4–5 for Model 1 (2.01° ± 1.39°), Model 2 (2.00° ± 1.52°), and Model 3 (1.15° ± 0.80°) was significantly lower than the intact condition (5.02° ± 2.90°) (p < 0.001). Moreover, axial rotation for the intact condition and Model 3 at L5–right ilium (2.64° ± 1.36° and 2.93° ± 1.68°, respectively) and L5–left ilium (2.58° ± 1.43° and 2.93° ± 1.71°, respectively) was significantly lower than for Model 1 and Model 2 at L5–right ilium (5.14° ± 2.48° and 4.95° ± 2.45°, respectively) (p = 0.036) and L5–left ilium (5.19° ± 2.34° and 4.99° ± 2.31°) (p = 0.022). Last, results of the axial compression testing at all measured points were not statistically different among reconstructions.CONCLUSIONSThe addition of a transverse bar in Model 2 offered no biomechanical advantage. Although the implementation of 4 iliac screws and 4 rods conferred a definitive kinematic advantage in Model 3, that model was associated with significantly restricted lumbopelvic ROM.
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Affiliation(s)
- Mohamed Macki
- 1Department of Neurosurgery, Henry Ford Hospital, Detroit, Michigan
| | | | - Ashley A. Murgatroyd
- 3Orthopaedic Spinal Research Institute, St. Joseph Medical Center, University of Maryland, Towson, Maryland
| | - Kenneth P. Mullinix
- 3Orthopaedic Spinal Research Institute, St. Joseph Medical Center, University of Maryland, Towson, Maryland
| | - Xiaolei Sun
- 3Orthopaedic Spinal Research Institute, St. Joseph Medical Center, University of Maryland, Towson, Maryland
| | - Bryan W. Cunningham
- 3Orthopaedic Spinal Research Institute, St. Joseph Medical Center, University of Maryland, Towson, Maryland
| | | | - Mohamad Bydon
- 4Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota; and
| | - Ziya L. Gokaslan
- 5Department of Neurosurgery, Warren Alpert Medical School of Brown University, Providence, Rhode Island
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Biomechanical evaluation of supplemental percutaneous lumbo-sacro-iliac screws for spinopelvic fixation following total sacrectomy. ACTA ACUST UNITED AC 2015; 28:E181-5. [PMID: 25905801 DOI: 10.1097/bsd.0000000000000241] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
STUDY DESIGN This is a cadaveric biomechanical study evaluating the biomechanical properties of a novel spinopelvic fixation technique with percutaneous lumbo-sacro-iliac (LSI) screws in an unstable total sacrectomy model. OBJECTIVE To compare standard posterior dual rod spinopelvic fixation alone with dual rod fixation supplemented with LSI screw fixation. SUMMARY OF BACKGROUND DATA Primary or metastatic tumors of the sacrum requiring a total sacrectomy can result in spinopelvic instability if inadequate fixation is achieved. Many fixation techniques have been proposed to address this instability. However, to date, an optimal fixation technique has not been established. MATERIALS AND METHODS Ten fresh-frozen cadaveric spinopelvic specimens were randomized according to bone mineral density (BMD) to either posterior rod fixation (control group) or posterior rod fixation with supplemental LSI screws (LSI group). After fixation, a total sacrectomy of each specimen was performed. Specimens where then potted and axially loaded in a caudal direction. Stiffness, yield load, energy absorbed at yield load, ultimate load, and energy absorbed at ultimate load were computed. A Student t test was used for statistical analysis with significance set at P<0.05. RESULTS The average age and BMD were not significantly different between the control and LSI groups (age: P=0.255; BMD: P=0.810). After normalizing for BMD, there were no significant differences detected for any of the biomechanical parameters measured between the 2 fixation techniques: stiffness (P=0.857), yield load (P=0.219), energy at yield load (P=0.293), ultimate load (P=0.407), and energy at ultimate load (P=0.773). However, both fixation techniques were able to withstand physiological loads. CONCLUSIONS Our study did not demonstrate any biomechanical advantage for supplemental LSI screw fixation in our axial loading model. However, given the theoretical advantage of this percutaneous technique, further studies are warranted that take into account forward bending and sagittal stability.
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Khansa I, Janis JE. Modern reconstructive techniques for abdominal wall defects after oncologic resection. J Surg Oncol 2014; 111:587-98. [DOI: 10.1002/jso.23824] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Accepted: 09/09/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Ibrahim Khansa
- Department of Plastic Surgery; The Ohio State University Wexner Medical Center; Columbus Ohio
| | - Jeffrey E. Janis
- Department of Plastic Surgery; The Ohio State University Wexner Medical Center; Columbus Ohio
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Hanlon AD, Cook DJ, Yeager MS, Cheng BC. Quantitative Analysis of the Nonlinear Displacement–Load Behavior of the Lumbar Spine. J Biomech Eng 2014; 136:1877321. [DOI: 10.1115/1.4027754] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 05/29/2014] [Indexed: 11/08/2022]
Abstract
There is currently no universal model or fitting method to characterize the visco-elastic behavior of the lumbar spine observed in displacement versus load hysteresis loops. In this study, proposed methods for fitting these loops, along with the metrics obtained, were thoroughly analyzed. A spline fitting technique was shown to provide a consistent approximation of spinal kinetic behavior that can be differentiated and integrated. Using this tool, previously established metrics were analyzed using data from two separate studies evaluating different motion preservation technologies. Many of the metrics, however, provided no significant differences beyond range of motion analysis. Particular attention was paid to how different definitions of the neutral zone capture the high-flexibility region often seen in lumbar hysteresis loops. As a result, the maximum slope was introduced and shown to be well defined. This new parameter offers promise as a descriptive measurement of spinal instability in vitro and may have future implications in clinical diagnosis and treatment of spinal instability. In particular, it could help in assigning treatments to specific stabilizing effects in the lumbar spine.
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Affiliation(s)
- Andrew D. Hanlon
- Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Pittsburgh, PA 15212
| | - Daniel J. Cook
- Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Pittsburgh, PA 15212
| | - Matthew S. Yeager
- Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Pittsburgh, PA 15212
| | - Boyle C. Cheng
- Department of Neurosurgery, Allegheny General Hospital, 420 East North Avenue, Pittsburgh, PA 15212 e-mail:
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Clark AJ, Tang JA, Leasure JM, Ivan ME, Kondrashov D, Buckley JM, Deviren V, Ames CP. Gait-simulating fatigue loading analysis and sagittal alignment failure of spinal pelvic reconstruction after total sacrectomy: comparison of 3 techniques. J Neurosurg Spine 2014; 20:364-70. [PMID: 24460580 DOI: 10.3171/2013.12.spine13386] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Reconstruction after total sacrectomy is a critical component of malignant sacral tumor resection, permitting early mobilization and maintenance of spinal pelvic alignment. However, implant loosening, graft migration, and instrumentation breakage remain major problems. Traditional techniques have used interiliac femoral allograft, but more modern methods have used fibular or cage struts from the ilium to the L-5 endplate or sacral body replacement with transiliac bars anchored to cages to the L-5 endplate. This study compares the biomechanical stability under gait-simulating fatigue loading of the 3 current methods. METHODS Total sacrectomy was performed and reconstruction was completed using 3 different constructs in conjunction with posterior spinal screw rod instrumentation from L-3 to pelvis: interiliac femur strut allograft (FSA); L5-iliac cage struts (CSs); and S-1 body replacement expandable cage (EC). Intact lumbar specimens (L3-sacrum) were tested for flexion-extension range of motion (FE-ROM), axial rotation ROM (AX-ROM), and lateral bending ROM (LB-ROM). Each instrumented specimen was compared with its matched intact specimen to generate an ROM ratio. Fatigue testing in compression and flexion was performed using a custom-designed long fusion gait model. RESULTS Compared with intact specimen, the FSA FE-ROM ratio was 1.22 ± 0.60, the CS FE-ROM ratio was significantly lower (0.37 ± 0.12, p < 0.001), and EC was lower still (0.29 ± 0.14, p < 0.001; values are expressed as the mean ± SD). The difference between CS and EC in FE-ROM ratio was not significant (p = 0.83). There were no differences in AX-ROM or LB-ROM ratios (p = 0.77 and 0.44, respectively). No failures were noted on fatigue testing of any EC construct (250,000 cycles). This was significantly improved compared with FSA (856 cycles, p < 0.001) and CS (794 cycles, p < 0.001). CONCLUSIONS The CS and EC appear to be significantly more stable constructs compared with FSA with FE-ROM. The 3 constructs appear to be equal with AX-ROM and LB-ROM. Most importantly, EC appears to be significantly more resistant to fatigue compared with FSA and CS. Reconstruction of the load transfer mechanism to the pelvis via the L-5 endplate appears to be important in maintenance of alignment after total sacrectomy reconstruction.
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Yu Y, Zhu R, Zeng ZL, Jia YW, Wu ZR, Ren YL, Chen B, Ding ZQ, Cheng LM. The strain at bone-implant interface determines the effect of spinopelvic reconstruction following total sacrectomy: a strain gauge analysis in various spinopelvic constructs. PLoS One 2014; 9:e85298. [PMID: 24454839 PMCID: PMC3891848 DOI: 10.1371/journal.pone.0085298] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 11/25/2013] [Indexed: 11/20/2022] Open
Abstract
PURPOSE There is still some controversy regarding the optimal biomechanical concept for spinopelvic stabilization following total sacrectomy for malignancy. Strains at specific anatomical sites at pelvis/sacrum and implants interfaces have been poorly investigated. Herein, we compared and analyzed the strains applied at key points at the bone-implant interface in four different spinopelvic constructs following total sacrectomy; consequently, we defined a balanced architecture for spinopelvic fusion in that situation. METHODS Six human cadaveric specimens, from second lumbar vertebra to proximal femur, were used to compare the partial strains at specific sites in a total sacrectomy model. Test constructs included: (1) intact pelvis (control), (2) sacral-rod reconstruction (SRR), (3) bilateral fibular flap reconstruction (BFFR), (4) four-rods reconstruction (FRR), and (5) improved compound reconstruction (ICR). Strains were measured by bonded strain gauges onto the surface of three specific sites (pubic rami, arcuate lines, and posterior spinal rods) under a 500 N axial load. RESULTS ICR caused lower strains at specific sites and, moreover, on stress distribution and symmetry, compared to the other three constructs. Strains at pubic rami and arcuate lines following BFFR were lower than those following SRR, but higher at the posterior spinal rod construct. The different modes of strain distribution reflected different patient's parameter-related conditions. FRR model showed the highest strains at all sites because of the lack of an anterior bracing frame. CONCLUSIONS The findings of this investigation suggest that both anterior bracing frame and the four-rods load dispersion provide significant load sharing. Additionally, these two constructs decrease the peak strains at bone-implant interface, thus determining the theoretical surgical technique to achieve optimal stress dispersion and balance for spinopelvic reconstruction in early postoperative period following total sacrectomy.
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Affiliation(s)
- Yan Yu
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Rui Zhu
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
- Julius Wolff Institut, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Zhi-Li Zeng
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yong-Wei Jia
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Zhou-Rui Wu
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yi-Long Ren
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
| | - Bo Chen
- School of Life Science and Technology, Tongji University, Shanghai, China
- Institute of Orthopaedics and Traumatology, Shanghai, China
| | - Zu-Quan Ding
- School of Life Science and Technology, Tongji University, Shanghai, China
| | - Li-Ming Cheng
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, Shanghai, China
- * E-mail:
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Cai Y, Li Z, Gu X, Fang Y, Xiang J, Chen Z. Prognostic factors associated with locally recurrent rectal cancer following primary surgery (Review). Oncol Lett 2013; 7:10-16. [PMID: 24348812 PMCID: PMC3861572 DOI: 10.3892/ol.2013.1640] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 10/15/2013] [Indexed: 12/17/2022] Open
Abstract
Locally recurrent rectal cancer (LRRC) is defined as an intrapelvic recurrence following a primary rectal cancer resection, with or without distal metastasis. The treatment of LRRC remains a clinical challenge. LRRC has been regarded as an incurable disease state leading to a poor quality of life and a limited survival time. However, curative reoperations have proved beneficial for treating LRRC. A complete resection of recurrent tumors (R0 resection) allows the treatment to be curative rather than palliative, which is a milestone in medicine. In LRRC cases, the difficulty of achieving an R0 resection is associated with the post-operative prognosis and is affected by several clinical factors, including the staging of the local recurrence (LR), accompanying symptoms, patterns of tumors and combined therapy. The risk factors following primary surgery that lead to an increased rate of LR are summarized in this study, including the surgical, pathological and therapeutic factors.
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Affiliation(s)
- Yantao Cai
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Zhenyang Li
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Xiaodong Gu
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Yantian Fang
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Jianbin Xiang
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
| | - Zongyou Chen
- Department of General Surgery, Huashan Hospital, Fudan University, Shanghai 200040, P.R. China
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Biomechanical comparison of spinopelvic reconstruction techniques in the setting of total sacrectomy. Spine (Phila Pa 1976) 2012; 37:E1622-7. [PMID: 23038619 DOI: 10.1097/brs.0b013e31827619d3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An in vitro biomechanical study. OBJECTIVE To biomechanically test and evaluate 4 different methods of spinopelvic reconstruction techniques and determine the most biomechanically stable construct for stabilization of the spinopelvic junction after total sacrectomy. SUMMARY OF BACKGROUND DATA Total sacrectomy is necessary to treat a sacral tumor when it involves the S1 vertebra. Instrumentation and reconstruction of the lumbar spine and pelvis are required after total sacrectomy and can be achieved by various reconstruction techniques. Currently, the preferred method of spinopelvic fixation is controversial. METHODS Seven human cadaveric (L1-pelvis) specimens were evaluated in flexion-extension, lateral bending, and axial rotation in a total sacrectomy model. Test constructs included (1) intact; (2) double-rod, double iliac screw (DDS); (3) single-rod, single iliac screw (SSS); (4) double iliac screw (DIS) fixation; and (5) modified Galveston technique (MGT). A load control protocol with 7.0 Nm moments applied at a rate of 1.5°/s was used to establish range of motion values for each tested construct on a 6-df spine motion simulator. Data were analyzed and normalized to intact. RESULTS All instrumented constructs offered significant stability in all loading conditions compared with the intact condition. Stability offered by different constructs in all loading conditions trended as follows: DDS>DIS>SSS>MGT. Overall, the DDS construct provided 55%, 43%, and 60% more stability than SSS, DIS, and MGT, respectively. This was significant in flexion-extension when compared with SSS and in all loading conditions when compared with MGT. CONCLUSION In the setting of total sacrectomy, the double-rod double iliac screw method provided the most rigid fixation, followed by DIS fixation, single-rod single screw, and the MGT. In spinopelvic reconstruction, the use of double iliac screws is recommended compared with single iliac screw fixation techniques when treating unstable conditions caused by total sacrectomy.
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Zhu R, Cheng LM, Yu Y, Zander T, Chen B, Rohlmann A. Comparison of four reconstruction methods after total sacrectomy: a finite element study. Clin Biomech (Bristol, Avon) 2012; 27:771-6. [PMID: 22705158 DOI: 10.1016/j.clinbiomech.2012.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 05/15/2012] [Accepted: 05/16/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND After total sacrectomy, it is mandatory to reconstruct the continuity between the lumbar spine and the pelvis. Only few biomechanical analyses exist which compare different reconstructions. Therefore, the aim of this study was to compare the lumbo-pelvic motion and the relative risk of implant breakage for four different reconstructions after total sacrectomy. METHOD Finite element analyses were performed for four general different reconstructions after total sacrectomy: sacral-rod reconstruction, four-rod reconstruction, bilateral fibular flaps reconstruction, and improved compound reconstruction. The rotations between L5 vertebra and ilium, the L5 shift-down displacement, and the maximum von Mises stress in the implants were calculated and evaluated for flexion, extension, lateral bending and axial rotation. FINDINGS The decreasing order of the rotations between L5 vertebra and ilium as well as of the L5 shift-down displacement for the studied reconstruction methods was four-rod reconstruction>sacral-rod reconstruction>bilateral fibular flaps reconstruction>improved compound reconstruction. The decreasing order of the maximum von Mises stress in the implants was sacral-rod reconstruction>four-rod reconstruction>bilateral fibular flaps reconstruction>improved compound reconstruction. INTERPRETATION From the mechanical point of view, improved compound reconstruction is superior to the other methods studied here as it shows the highest stability and the lowest maximum von Mises stress. However, clinical aspects must also be regarded when choosing a reconstruction method for a specific patient.
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Affiliation(s)
- Rui Zhu
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, 200065 Shanghai, PR China
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