The effect of large-channel endoscopy combined with visualization of trephines for foraminoplasty on lumbar biomechanics: a finite element analysis

The effect of large-channel endoscopy combined with visualization of trephines for foraminoplasty on lumbar biomechanics: a finite element analysis | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article The effect of large-channel endoscopy combined with visualization of trephines for foraminoplasty on lumbar biomechanics: a finite element analysis Duohua Li, Hao Fu, Sicong Zhao, Xiao Gao, Dongying Wu, Hu Feng, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-5411592/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose: This study aimed to evaluate the effect of the degree of facet joint resection under the combined action of large-channel endoscopy and visualized trephines on lumbar biomechanics. Methods: The original CT data of a healthy male volunteer were selected. An L3-5 lumbar spine model, M0,was established via thethree-dimensional finite element method. Different degrees of resection of the superior articular process of L4 were simulated via a visualized trephine during the operation, and six models were established (M1: tip resection; M2: resection of the ventral 1/3; M3: resection of the ventral 1/2; M4: resection of the ventral 2/3; M5: resection of the ventral 3/4; and M6: complete resection). Loads were applied to the model to simulate six motions of flexion, extension, left/right lateral bending, and left/right rotation. The stress distributions of the vertebral body, intervertebral disc and articular cartilage of the L3-4 segment and adjacent segments wereobserved. Results: When the degree of facet joint resection does not exceed 1/2, there is no significant change in the pressure of the vertebral body, intervertebral disc and facet joint in M1, M2 and M3. When the degree of facet joint resection exceeds 1/2, the pressure on the L3, L4 and L5 vertebral bodies in models M4, M5 and M6 increases significantly. The pressure of the L3-4 intervertebral disc increases while the pressure of the L4-5 intervertebral disc tends to decrease. The pressure of the facet joints on both sides of L3-4 increases, and the pressure increase on the left facet joint is relatively large. Conclusion: When more than half of the superior articular process of L4 is resected under large-channel endoscopy, the stress on the vertebral body, intervertebral disc and articular cartilage of the L3-4 segment increases, which may cause iatrogenic instability but has no significant effect on the stress on the vertebral body or intervertebral disc of adjacent segments. Lumbar disc herniation Biomechanical Foraminoplasty Visible trephine Finite element Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 1. Introduction Lumbar disc herniation (LDH) is a common and frequently occurring disease in orthopedics. The main symptoms are low back pain, radiating pain in the lower extremities and numbness of the limbs. Most patients can relieve symptoms through nonsurgical treatments such as bed rest and traction. If conservative treatment is ineffective or symptoms of cauda equina nerve compression appear, surgical treatment is needed. Compared with conservative treatment, surgical treatment can quickly relieve symptoms such as leg pain [1-4]. At present, percutaneous endoscopic transforaminal discectomy (PETD) is one of the main surgical methods for treating lumbar disc herniation. It uses a transforaminal endoscope to remove the protruding nucleus pulposus through the intervertebral foramen, relieving compression and reducing the patient's pain. This surgical method has the advantages of being minimally invasive, having a short operation time, resulting in less blood loss, a short hospital stay and high postoperative satisfaction [5-7]. Studies [8-9] have shown that extensive resection and exposure of the facet joint may lead to significant asymmetric stress changes in the bilateral facet joints and range of motion (ROM) instability in the surgical and adjacent segments. Shi et al. [10] reported that the disc stress of L4/L5 significantly increased in most directions of motion when more than 3/5 of the superior facet of S1 was formed from the ventral to the dorsal or 1/5 from the apex to the base. Owing to factors such as facet joint hyperplasia and foraminal stenosis, unilateral foraminoplasty is often required during the operation to expand the working channel (surgical space) and better expose the protruding intervertebral disc, dural sac and nerve root. In this process, the facet joint will be damaged to varying degrees. With the innovation of surgical instruments, the application of trephines can grind part of the superior facet joint, expand the intervertebral foramen, and then place the working channel. However, it is impossible to precisely control the location and scope of facet joint resection. The emergence of visualized trephines has solved this problem. Using visualized trephines can control the degree of facet joint resection and reduce damage to the exiting nerve root and dorsal root ganglion during puncture and catheter placement. The incidence rate of LDH is approximately 2% to 3%. 95% of LDH occurs at L4-5 and L5-S1, followed by L3-4[11-12]. Many studies have investigated lumbar biomechanics after surgery for lumbar disc herniation at the L4‒5 and L5‒S1 segments, whereas relatively few studies have focused on the L3‒4 segment. However, the biomechanics of the L4-5 segment are not completely applicable to the L3-4 segment. Therefore, in this study, three-dimensional finite element analysis was used to analyze the impact of the degree of resection of the L3 facet joint under the combined action of large-channel endoscopy and visualization of the trephine via PETD on lumbar biomechanics. Finite element analysis (FEA) can predict the part with the greatest force on the spinal unit, provides a reference for clinical practice, and has a low cost and no risk to patients [13]. 2. Materials and methods 2.1 Patient CT data collection and lumbar spine modeling One healthy adult male volunteer (35 years old, height 168 cm, weight 75 kg) was selected, excluding those with spinal diseases. A Siemens 64-slice spiral CT system (Siemens Sensation Open CT scanner, Siemens, Erlangen, Germany) provided by the imaging department of the Affiliated Hospital of Xuzhou Medical University was used to perform spiral scanning and tomographic image processing on the L3--L5 region of the selected subject. During scanning, the volunteer was in a supine position, and the scanning cross-section was maintained perpendicular to the long axis of the body as much as possible. The scanning parameters were as follows: voltage, 120 kV; layer thickness, 0.699 mm; and tube current, 200 Ma. The CT image data are exported in Digital Imaging and Communications in Medicine (DICOM) format for backup. The patient's lumbar spine CT data were imported into Mimics in DICOM format. The bones are segmented by setting the gray value threshold. The segmentation threshold is set to 226--1612, the region growth mode is set to "6-connectivity", and the model is optimized through mask separation, filling and mask editing. The masks of each vertebra obtained via segmentation are sequentially subjected to three-dimensional reconstruction. The 3D reconstruction quality is selected as the "high" quality level. After the three-dimensional model is obtained, smoothing processing is performed, "iterations" is set to 5, and the "smooth factor" is set to 0.4. After the 3D model is reconstructed, it is saved in the STL format. The stored file is imported into Geomagic wrap, triangular patches with a side length of 1.0 mm are regenerated, and then problems such as "small holes and highly refracted edges" are repaired. When smoothing, the smoothing level is set to the intermediate value. Accurate surface processing is performed on each vertebra model to obtain a solid model of each vertebra. According to the literature [14], the thickness of cortical bone is 2–3 mm. The "offset" operation was used to offset the vertebral body model as a whole by 2.5 mm inward, and the cortical bone part was removed. The three lumbar vertebrae are processed in turn to obtain models of the vertebrae and cancellous bone parts, and the models are stored as part of the STEP files. The parts in SolidWorks are assembled to form an assembly. The intervertebral disc is generated between adjacent vertebral bodies through the "boss feature", and endplates with a thickness of 1 millimeter are created on the upper and lower surfaces. The intervertebral disc, which is composed of the annulus fibrosus and nucleus pulposus, lies between the upper and lower endplates. First, the nucleus pulposus was added between the upper and lower endplates. The nucleus pulposus is modeled as an incompressible liquid-filled cavity. Then, four 1.5 mm thick concentric rings around the nucleus pulposus were added to form the annulus fibrosus. The fibers of the annulus fibrosus are composed of rod-like elements that can only bear tension. The fibers move in a scissor-like manner in the annulus fibrosus and form an average angle of 25° to 40° with the intervertebral disc. The nucleus pulposus accounts for approximately 44% of the volume of the intervertebral disc. The center of the nucleus pulposus is located approximately 3.5 millimeters behind the center of the intervertebral disc. The articular cartilage between the upper and lower facet joints was constructed through "drawing sketches, stretching bosses and combinations". 2.2 Establishment of the articular process resection model On the basis of the normal three-dimensional finite element model of L3--L5, according to the intraoperative situation, SolidWorks software was used to simulate the surgical process, and an 8.5 mm trephine was used to resect the facet joints to different degrees to establish the following three-dimensional finite element models: ① Unected model (Model 0, M0, Fig. 1a); ② Superior facet joint apex foraminoplasty model (Model 1, M1, Fig. 1b); ③ The ventral 1/3 foraminoplasty model of the superior facet joint (Model 2, M2, Fig. 1c); ④ The ventral 1/2 foraminoplasty model of the superior facet joint (Model 3, M3, Fig. 1d); ⑤ The ventral 2/3 foraminoplasty model of the superior facet joint (Model 4, M4, Fig. 1e); ⑥ Ventral 3/4 foraminoplasty model of the superior facet joint (Model 5, M5, Fig. 1f); ⑦ Model of complete resection of the superior facet joint (Model 6, M6; Fig. 1g). 2.3 Building a complete model The complete three-dimensional finite element model is imported into ANSYS 21.0 for finite element analysis. Spring elements with nonlinear material properties are used to construct ligaments (Fig. 2a), including the anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), ligamentum flavum (LF), interspinous ligament (ISL), supraspinous ligament (SSL), capsular ligament (CL), and intertransverse ligament (ITL). According to the literature, the material properties in Table 1 are assigned to each ligament and structure in the material library, including the cortical bone, cancellous bone, nucleus pulposus, annulus fibrosus, endplate, and articular cartilage. The contact type between the facet joint cartilage and the vertebral surface is set as "No separation", and the contact gap range of the facet joint cartilage surface is set to 0.1 mm. The contact between the surface of the lumbar intervertebral disc and the upper and lower endplates of each vertebral body is defined as the "bonded" mode. The upper and lower endplates of each vertebral body are taken as the master surface, and the upper and lower surfaces of the intervertebral disc are taken as the slave surface. Finally, the model is meshed (Fig. 2b). Table 1 Material parameters for finite element modeling Parts Young modulus/MPa Poisson’s ratio Sectional area/mm2 References Cortical bone 12000 0.3 Zhang X et al. [15] Cancellous bone 100 0.2 Zhang X et al. [15] Cartilage endplate 1000 0.4 Bereczki F et al. [16] Annulus fiber 4.2 0.45 Zhang Q et al. [17] Nucleus pulposus 1 0.499 Zhang Q et al. [17] Articular facet joints 10 0.4 Wu W et al. [8] ALL 20 0.3 60 Huang S et al. [18] PLL 20 0.3 21 LF 19.5 0.3 40 SSL 15 0.3 30 ISL 12 0.3 40 ITL 50 0.3 10 CL 7.5 0.3 67.5 2.4 Boundary conditions and load settings When the model is in a neutral position, the bottom of L5 is subject to fixed constraints, whereas the upper surface of the L3 vertebral body, where pressure and torque are applied, is unconstrained (Fig. 3). When the magnitude and direction of the load are set, a "component" is selected to set the load, the stress caused by the human body weight on the lumbar spine under different conditions is simulated, and the load is evenly transferred to the nodes on the surface. Pressure and torque are applied to the upper surface of the L3 vertebral body. The pressure and torque during flexion are 1175 N and 7.5 N·m, respectively; the pressure and torque during extension are 500 N and 7.5 N·m, respectively; the pressure and torque during lateral flexion are 700 N and 7.8 N·m, respectively; and the pressure and torque during rotation are 720 N and 5.5 N·m, respectively [19-21]. 2.5 Observation indicators The movement of the lumbar spine was simulated under six working conditions: forward flexion, backward extension, left and right lateral bending, and left and right rotation. The changes in the von Mises stress of L3, L4, and L5 in the seven models were observed, the changes in the von Mises stress of the L4–5 and L4–5 intervertebral discs were measured, and the changes in the von Mises stress of the articular cartilage between the facet joints on both sides of L4–5 were observed. 3. Results 3.1 Model validation Different loading directions, such as flexion, extension, left/right bending, and left/right rotation, are applied to the vertebral body model to obtain the range of motion data of the L3–L5 segment. The results are compared with the biomechanical experimental data of previous studies [ 22 ] and show good consistency (Fig. 4 ). This confirms the accuracy and reliability of the model and proves its suitability for subsequent simulation studies. 3.2 von Mises stress changes in the L4 vertebral body In the L4 vertebral body, when the resection of the superior facet joint exceeds 1/2, the von Mises stress of the vertebral body under the six working conditions increases significantly. The maximum stress is the largest during forward flexion and the smallest during backward extension. Under other working conditions, the maximum stress of the vertebral body is essentially the same. The maximum stresses of the L4 vertebral body under the six load conditions are 45.334, 19.319, 27.038, 27, 27.786 and 27.796 MPa, respectively (Fig. 5 a). 3.3 von Mises stress changes in the L3 and L5 vertebral bodies In the L3 and L5 vertebral bodies, when the degree of facet joint resection exceeds 1/2, the von Mises stress of both vertebral bodies increases, and the greater the degree of resection is, the greater the stress. However, the increase in amplitude is not as obvious as that of the L3 vertebral body. Under six load conditions, the maximum stresses of the L3 vertebral body are 23.232, 9.8931, 13.841, 13.846, 14.239 and 14.239 MPa, respectively (Fig. 5 b), and the maximum stresses of the L5 vertebral body are 17.097, 7.2774, 10.186, 10.187, 10.477 and 10.478 MPa, respectively (Fig. 5 c). Among the different movement states, the stress increase is most obvious during forward flexion, and the impact on adjacent vertebral bodies is the smallest during backward extension. 3.4 von Mises stress changes in the intervertebral disc In the L3-4 intervertebral disc, when the degree of facet joint resection exceeds 1/2, the von Mises stress of the intervertebral disc increases. The maximum stress is 1.5705 MPa, and the minimum stress is 0.66901 MPa. Under six load conditions, the maximum stresses of the L3-4 intervertebral disc are 1.5705, 0.66901, 0.93636, 0.93549, 0.96271 and 0.96262 MPa, respectively (Fig. 5 d). In the L4-5 intervertebral disc, as the resection volume continues to increase, the von Mises stress of the intervertebral disc tends to decrease overall. Under six load conditions, the minimum stresses of the L4-5 intervertebral disc are 1.5492, 0.65981, 0.92367, 0.92271, 0.94966 and 0.94948 MPa, respectively (Fig. 5 e). 3.5 von Mises stress changes in L3–L4 articular cartilage When the degree of facet joint resection exceeds 1/2, the von Mises stress of the articular cartilage on both sides increases significantly. The maximum stress on the left side is 49.739 MPa, and the minimum stress is 20.029 MPa. The maximum stress on the right side is 21.021 MPa, and the minimum stress is 7.15 MPa. Under six load conditions, the maximum stresses of the left facet joint of L3-4 are 49.739, 21.2, 29.665, 29.627, 30.494 and 30.492 MPa, respectively (Fig. 5 f), and the maximum stresses of the right facet joint are 21.021, 8.9671, 12.522, 12.544, 12.887 and 12.894 MPa, respectively (Fig. 5 g). When the two sides are compared, the stress of the articular cartilage on the right side of each model is significantly lower than that on the left side, and the stress change shows an asymmetric trend. 4. Discussion Lumbar disc herniation is a common spinal disease that often leads to a series of clinical symptoms, such as low back pain, numbness and pain in one lower limb or both lower limbs. When nonsurgical treatment is ineffective, surgical treatment should be considered. Percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID) are currently the most common minimally invasive surgical methods for treating lumbar disc herniation [ 23 ]. During PETD, depending on the size of the patient's intervertebral foramen and the location of the intervertebral disc herniation, foraminal plasty on one side is generally required to enlarge the intervertebral foramen. This process damages the facet joints and the articular cartilage to varying degrees, which may cause iatrogenic instability and accelerate degeneration [ 24 ]. At present, most lumbar disc herniations occur in the L4‒5 and L5‒S1 segments, and relatively few studies have investigated lumbar biomechanics after L3‒4 segment lumbar disc herniation surgery. Therefore, we used the CT scan data of the lumbar spine segments of volunteers to establish a finite element model and seven models to simulate possible situations during the operation. An analysis of the seven models revealed that when the degree of resection of the superior facet joint during foraminaloplasty exceeds 1/2, the stresses on the L3, L4 and L5 vertebral bodies under the six working conditions all increase significantly, and the greater the resection volume is, the greater the stress. The increase in stress is the greatest during forward flexion, and the increase in stress is the smallest during backward extension. The increased stress in the vertebral body during left/right lateral flexion and left/right rotation is essentially the same. This finding indicates that extensive resection of the facet joint may increase the degree of degeneration of the responsible segment and adjacent segment vertebral bodies. Shi et al. [ 25 ] reported that when a 15 mm endoscope is used to resect the superior facet joint, the surgical segment increases significantly during backward extension, right flexion, and left and right rotations. The adjacent segment only increases slightly during backward extension. After resection with a 7.5 mm or 10 mm endoscope, the pressure applied to the adjacent segment vertebral body was similar to that applied to the unresected vertebral body. Therefore, the greater the resection volume of the superior facet joint is, the greater the impact on the adjacent segment vertebral body. Wu et al. [ 8 ] reported significant stress differences in the intervertebral discs of surgical segments, whereas no obvious stress changes were observed in the intervertebral discs of adjacent segments. This study revealed that when the degree of resection of the superior facet joint exceeds 1/2, the stress on the L3-4 intervertebral disc in the seven models increases. However, in the L4-5 intervertebral disc, as the resection volume of the facet joint increases, the stress of the intervertebral disc gradually decreases. This finding indicates that extensive resection of the facet joint may increase degeneration of the intervertebral disc in the responsible segment but has no obvious effect on the intervertebral disc in the adjacent segment. Shi et al. [ 10 ] reported that when S1 superior facet joint foraminoplasty is greater than 3/5, the stress of the intervertebral disc in the surgical segment significantly increases in most movement directions, which is similar to our research results. When the degree of resection of the articular process of the superior articular joint exceeds 1/2, the stress on the articular cartilage on both sides increases significantly. Moreover, the stress increase amplitude of the articular cartilage on the left side is greater than that on the right side. The stress on both sides shows an asymmetric change. The greater the forming amplitude is, the greater the stress on the contralateral articular cartilage. This may lead to long-term effects such as degenerative scoliosis. This suggests that when performing facet joint foraminoplasty, it is best to be close to the medial side and reduce the grinding of the facet joint as much as possible on the premise of sufficient decompression. Wu et al. [ 8 ] reported that after L4/5 foraminal plasty, the stresses of the L3/4 and L5/S1 facet joints decreased, whereas the stresses of the L4/5 facet joints generally tended to increase. Significant asymmetric stress changes in the bilateral facet joints were observed in all three segments, especially during bilateral rotational movements, suggesting that unnecessary and excessive resection should be avoided in PTED to reduce the incidence of low back pain and the risk of postoperative degeneration. Some studies have shown that, compared with resection alone, simultaneous resection of the tip and base of the superior articular process increases the stress on the facet joints in various motion states. Some studies have shown that under forward flexion and right lateral flexion, the increase in facet joint stress caused by resection of the tip of the superior articular process is smaller than that when the base is resected, whereas the opposite result is found under left lateral flexion, backward extension and rotation [ 26 ]. In this study, we found that when the articular cartilage is not damaged, the stress of the facet joint does not significantly change and has little impact on spinal stability. This finding indicates that when performing foraminal plasty, damage to the articular cartilage should be avoided as much as possible. This study also has the following shortcomings. First, the finite element model established in this study simplifies the muscles connected to the lumbar spine and the weight of the upper body, and there is still a certain difference from the real human body. Second, factors associated with the annulus fibrosus, such as annulus fibrosus damage, reduced nucleus pulposus volume, and endplate damage caused by intervertebral disc resection, are not considered. Moreover, the formation of scar tissue in the surgical area and the ingrowth of new bone tissue after surgery also have a certain impact on the stability of the lumbar spine. Third, the finite element model analysis in this study is a one-time load study and cannot systematically analyze the impact of fatigue loading on the biomechanics of the lumbar spine. Although the spinal finite element model is increasingly in line with human anatomy compared with previous designs, more refinements are still needed to obtain more accurate shapes and physical properties to increase the biomechanical application range of personalized finite element spinal models. 5. Conclusions In this study, a normal L3‒L5 segment finite element model was established; on this basis, a facet joint tip foraminoplasty model, a 1/3 facet joint foraminoplasty model, a 1/2 facet joint foraminoplasty model, a 2/3 facet joint foraminoplasty model, a 3/4 facet joint foraminoplasty model and a complete resection model of the superior facet joint were established. The model is successfully verified, the prediction results are credible, and the model can be used for biomechanical analysis and surgical condition simulation. When facet joint foraminoplasty under the combined action of large-channel endoscopy and visualized trephine exceeds 1/2, it increases the stress of the vertebral body, intervertebral disc and facet joint of the surgical segment, causes asymmetric stress on the facet joints on both sides, and may cause iatrogenic instability; however, it does not cause degeneration of the intervertebral disc in adjacent segments. Abbreviations LDH Lumbar disc herniation PETD Percutaneous endoscopic transforaminal discectomy ROM Range of motion FEA Finite Element Analysis DICOM Digital Imaging and Communications in Medicine PEID Percutaneous endoscopic interlaminar discectomy Declarations Ethics approval and consent to participate All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study. The Affiliated Hospital of Xuzhou Medical University Ethics Committee reviewed and approved the study protocol. Consent for publication Not applicable. Availability of data and materials The data used to support the findings of this study are included within the article. Competing interests The authors declare no competing interests. Funding This study was support by the Xuzhou Young Reserve Medical Talent Development Project (XWRCHT20220038) and the Xuzhou Science and Technology Project (KC21210). Authors' contributions D.L. and H.F. carried out the model development and simulation, data analysis and drafted the manuscript. W.S., S.Z., D.W., X.G. participated in the study design. D.L., H.F., S.Z., W.S. participated in revising the manuscript. W.S. and H.F. devised the concept and supervised the study. All authors read and approved the final manuscript. Acknowledgements Not applicable. References Zhang B, He Z, Guo J, Li F, Huang Z, Zheng W, Xing W, Li M, Zhu Y, Yang X. Sesamin-mediated high expression of BECN2 ameliorates cartilage endplate degeneration by reducing autophagy and inflammation. Aging (Albany NY). 2024 Jan 26;16(2):1145-1160. doi: 10.18632/aging.205386. Epub 2024 Jan 26. Linhardt O, Grifka J, Benditz A. 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Med Eng Phys. 2012 Jul;34(6):777-80. doi: 10.1016/j.medengphy.2012.04.002. Shim CS, Park SW, Lee SH, Lim TJ, Chun K, Kim DH. Biomechanical evaluation of an interspinous stabilizing device, Locker. Spine (Phila Pa 1976). 2008 Oct 15;33(22):E820-7. doi: 10.1097/BRS.0b013e3181894fb1. Pan M, Li Q, Li S, Mao H, Meng B, Zhou F, Yang H. Percutaneous Endoscopic Lumbar Discectomy: Indications and Complications. Pain Physician. 2020 Jan;23(1):49-56. PMID: 32013278. Sun W, Li D, Zhao S, Fu H, Tian J, Zhang F, Feng H, Wu D. The effect of large channel-based foraminoplasty on lumbar biomechanics in percutaneous endoscopic discectomy: a finite element analysis. J Orthop Surg Res. 2024 Jul 12;19(1):402. doi: 10.1186/s13018-024-04870-1. Shi Y, Xie YZ, Zhou Q, Yu Y, Fan XH. The biomechanical effect of the relevant segments after facet-disectomy in different diameters under posterior lumbar percutaneous endoscopes: a three-dimensional finite element analysis. J Orthop Surg Res. 2021 Oct 14;16(1):593. doi: 10.1186/s13018-021-02733-7. Wu Z, Sun H, Zhang Y, Xiao L, Zhao Q. Biomechanical Finite Element Analysis of Percutaneous Endoscopic Lumbar Discectomy via a Transforaminal Approach. World Neurosurg. 2024 May;185:e291-e298. doi: 10.1016/j.wneu.2023.10.108. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-5411592","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":376346262,"identity":"d2fdef1d-5534-4646-b5be-2c1a6334f937","order_by":0,"name":"Duohua Li","email":"","orcid":"","institution":"Graduate School of Xuzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Duohua","middleName":"","lastName":"Li","suffix":""},{"id":376346265,"identity":"517e88cb-6d1d-4da9-8b1e-b5906b68e872","order_by":1,"name":"Hao Fu","email":"","orcid":"","institution":"Graduate School of Xuzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Hao","middleName":"","lastName":"Fu","suffix":""},{"id":376346266,"identity":"1fb95163-01b9-400e-a935-1c74ee584e7e","order_by":2,"name":"Sicong Zhao","email":"","orcid":"","institution":"Graduate School of Xuzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Sicong","middleName":"","lastName":"Zhao","suffix":""},{"id":376346267,"identity":"cf73a1ff-9fe8-4f37-af61-78fd07e64d24","order_by":3,"name":"Xiao Gao","email":"","orcid":"","institution":"Affiliated Hospital of Xuzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Xiao","middleName":"","lastName":"Gao","suffix":""},{"id":376346268,"identity":"f155f138-2d9c-4ee3-a317-e0a8221204e3","order_by":4,"name":"Dongying Wu","email":"","orcid":"","institution":"Affiliated Hospital of Xuzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Dongying","middleName":"","lastName":"Wu","suffix":""},{"id":376346269,"identity":"10687d64-73e4-41a4-a74f-b9b2dd1cf99d","order_by":5,"name":"Hu Feng","email":"","orcid":"","institution":"Affiliated Hospital of Xuzhou Medical University","correspondingAuthor":false,"prefix":"","firstName":"Hu","middleName":"","lastName":"Feng","suffix":""},{"id":376346272,"identity":"61aa03ae-8ef7-4f6c-849d-a41dc34e9519","order_by":6,"name":"Wei Sun","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAyUlEQVRIiWNgGAWjYBACNmbGBsOPf2x47JuZDxCnhY+duaFYsiFNxoC9LYE4LXL87A0feBsO2xjwnDEg2mGNGyR3MPOYS+R8vPGGwU5Ot4GwlmaDwjNsPJYzcjdbzmFINjY7QFhLm4EEGw8Pw43cbdI8DAcStxGhpf0HD5sEUEvOM6K1NBjwthnwGJw5w0a8FmOJMwk8ku1txpZzDIjwi3z/8QeGHyr+2/MzMz+88abCTo6gFhQgwUNk1CBrIVXHKBgFo2AUjAgAAFIHO50x2nllAAAAAElFTkSuQmCC","orcid":"","institution":"Affiliated Hospital of Xuzhou Medical University","correspondingAuthor":true,"prefix":"","firstName":"Wei","middleName":"","lastName":"Sun","suffix":""}],"badges":[],"createdAt":"2024-11-07 17:08:07","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-5411592/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-5411592/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":69925199,"identity":"93894970-a780-474f-a361-64586c51dfb6","added_by":"auto","created_at":"2024-11-26 16:09:46","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":707505,"visible":true,"origin":"","legend":"\u003cp\u003eArticular process resection plan and results\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-5411592/v1/4f02e8cdf5c2b8823fec8da9.png"},{"id":69925200,"identity":"98d63c85-44b2-48c1-99ae-bdc7da6610be","added_by":"auto","created_at":"2024-11-26 16:09:46","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":797665,"visible":true,"origin":"","legend":"\u003cp\u003ea. Construction of ligaments by springunits; b. Mesh division of the finite element model\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-5411592/v1/ff36a88d4ffecb3e063698a0.png"},{"id":69924201,"identity":"cd4f3cb2-8334-47e7-8f8c-fda42d99374f","added_by":"auto","created_at":"2024-11-26 16:01:46","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":683373,"visible":true,"origin":"","legend":"\u003cp\u003ea. Securing the bottom of the model; b. Applying forces and moments to the top of the model\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-5411592/v1/90cd0479ecb87dba9d1a1108.png"},{"id":69924202,"identity":"67a4fe35-3f60-47cf-bc9f-9a8c4c77cef0","added_by":"auto","created_at":"2024-11-26 16:01:46","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":161313,"visible":true,"origin":"","legend":"\u003cp\u003e与Comparison with Shim's experimental data\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-5411592/v1/9052b9fba43d3d1956f59288.png"},{"id":69924199,"identity":"bff883d7-e52d-48c9-b2ae-f763de8db3af","added_by":"auto","created_at":"2024-11-26 16:01:46","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":101132,"visible":true,"origin":"","legend":"\u003cp\u003eMaximum von Mises stress of the vertebral body, annulus fibers and articular cartilage\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-5411592/v1/5ffec8718bf11774b87841e0.png"},{"id":104401320,"identity":"9f481e6a-1a49-4894-ba51-9be481a1e3e6","added_by":"auto","created_at":"2026-03-11 12:12:23","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4143164,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-5411592/v1/632eee2b-d685-4b0f-9c9b-f69b933bb48b.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"The effect of large-channel endoscopy combined with visualization of trephines for foraminoplasty on lumbar biomechanics: a finite element analysis","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eLumbar disc herniation\u0026nbsp;(LDH)\u0026nbsp;is a common and frequently\u0026nbsp;occurring disease in orthopedics. The main symptoms are low back pain, radiating pain in the lower extremities and numbness of the limbs. Most patients can relieve symptoms through\u0026nbsp;nonsurgical\u0026nbsp;treatments such as bed rest and traction. If conservative treatment is ineffective or symptoms of cauda equina nerve compression appear, surgical treatment is\u0026nbsp;needed. Compared with conservative treatment, surgical treatment can quickly relieve symptoms such as leg pain\u0026nbsp;[1-4].\u0026nbsp;At present, percutaneous endoscopic transforaminal discectomy (PETD) is one of the main surgical methods for treating lumbar disc herniation. It uses a transforaminal endoscope to remove the protruding nucleus pulposus through the intervertebral foramen, relieving compression and reducing the patient's pain. This surgical method has the advantages of being minimally invasive, having a short operation time,\u0026nbsp;resulting in\u0026nbsp;less blood loss, a short hospital stay and high postoperative satisfaction [5-7].\u0026nbsp;Studies [8-9] have shown that extensive resection and exposure of the facet joint may lead to significant asymmetric stress changes in\u0026nbsp;the\u0026nbsp;bilateral facet joints and range of motion (ROM) instability in the surgical and adjacent segments.\u0026nbsp;Shi et al.\u0026nbsp;[10]\u0026nbsp;reported\u0026nbsp;that the disc stress of L4/L5 significantly increased in most directions of motion when more than 3/5 of the superior facet of S1 was formed from the ventral to the dorsal or 1/5 from the apex to the base.\u003c/p\u003e\n\u003cp\u003eOwing\u0026nbsp;to\u0026nbsp;factors\u0026nbsp;such as facet joint hyperplasia and foraminal stenosis, unilateral foraminoplasty is often required during the operation to expand the working channel (surgical space) and better expose the protruding intervertebral disc, dural sac and nerve root. In this process, the facet joint will be damaged to varying degrees. With the innovation of surgical instruments, the application of trephines can grind part of the superior facet joint,\u0026nbsp;expand the intervertebral foramen, and then place the working channel. However, it is impossible to precisely control the location and scope of facet joint resection. The emergence of visualized trephines\u0026nbsp;has solved\u0026nbsp;this problem. Using visualized trephines can control the degree of facet joint resection and reduce damage to the exiting nerve root and dorsal root ganglion during puncture and catheter placement.\u003c/p\u003e\n\u003cp\u003eThe incidence rate of LDH is approximately 2% to 3%. 95% of LDH occurs at L4-5 and L5-S1, followed by L3-4[11-12]. Many studies have investigated lumbar biomechanics after surgery for lumbar disc herniation at the L4‒5 and L5‒S1 segments, whereas relatively few studies have focused on the L3‒4 segment. However, the biomechanics of the L4-5 segment are not completely applicable to the L3-4 segment. Therefore, in this study, three-dimensional finite element analysis was used to analyze the impact of the degree of resection of the L3 facet joint under the combined action of large-channel endoscopy and visualization of the trephine via PETD on lumbar biomechanics. Finite element analysis (FEA) can predict the part with the greatest force on the spinal unit, provides a reference for clinical practice, and has a low cost and no risk to patients [13].\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cp\u003e\u003cstrong\u003e2.1 Patient CT data collection and lumbar spine\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003emodeling\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOne healthy\u0026nbsp;adult\u0026nbsp;male volunteer (35 years old, height 168 cm, weight 75 kg) was selected, excluding\u0026nbsp;those with\u0026nbsp;spinal diseases.\u0026nbsp;A\u0026nbsp;Siemens 64-slice spiral CT\u0026nbsp;system\u0026nbsp;(Siemens Sensation Open CT scanner, Siemens, Erlangen, Germany) provided by the imaging department of the Affiliated Hospital of Xuzhou Medical University was used to perform spiral scanning and tomographic image processing on the L3--L5 region of the selected subject. During scanning, the volunteer was in a supine position,\u0026nbsp;and the scanning cross-section\u0026nbsp;was maintained\u0026nbsp;perpendicular to the long axis of the body as much as possible. The scanning parameters\u0026nbsp;were\u0026nbsp;as follows: voltage,\u0026nbsp;120\u0026nbsp;kV;\u0026nbsp;layer thickness,\u0026nbsp;0.699 mm;\u0026nbsp;and tube current,\u0026nbsp;200 Ma.\u0026nbsp;The\u0026nbsp;CT image data\u0026nbsp;are exported\u0026nbsp;in Digital Imaging and Communications in Medicine (DICOM) format for backup.\u003c/p\u003e\n\u003cp\u003eThe patient\u0026apos;s lumbar spine CT data\u0026nbsp;were\u0026nbsp;imported into Mimics in DICOM format. The bones are segmented by setting the gray value threshold. The segmentation threshold is set to 226--1612, the region growth mode is set to \u0026quot;6-connectivity\u0026quot;, and the model is optimized through mask separation, filling and mask editing. The masks of each vertebra obtained\u0026nbsp;via\u0026nbsp;segmentation are sequentially subjected to three-dimensional reconstruction. The 3D reconstruction quality is selected as the \u0026quot;high\u0026quot; quality level. After the three-dimensional model\u0026nbsp;is obtained, smoothing processing is performed, \u0026quot;iterations\u0026quot; is set to 5, and\u0026nbsp;the \u0026quot;smooth\u0026nbsp;factor\u0026quot; is set to 0.4. After the 3D model\u0026nbsp;is reconstructed, it is saved in\u0026nbsp;the\u0026nbsp;STL format.\u0026nbsp;The\u0026nbsp;stored file\u0026nbsp;is imported\u0026nbsp;into Geomagic wrap, triangular patches with a side length of 1.0 mm are regenerated, and then problems such as \u0026quot;small holes and highly refracted edges\u0026quot;\u0026nbsp;are repaired. When smoothing, the smoothing level\u0026nbsp;is set\u0026nbsp;to the intermediate value.\u0026nbsp;Accurate\u0026nbsp;surface processing\u0026nbsp;is performed\u0026nbsp;on each vertebra model to obtain\u0026nbsp;a\u0026nbsp;solid model of each vertebra.\u0026nbsp;According to\u0026nbsp;the\u0026nbsp;literature [14], the thickness of cortical bone is\u0026nbsp;2\u0026ndash;3\u0026nbsp;mm.\u0026nbsp;The\u0026nbsp;\u0026quot;offset\u0026quot; operation\u0026nbsp;was used\u0026nbsp;to offset the vertebral body model as a whole by 2.5 mm inward,\u0026nbsp;and the cortical bone part\u0026nbsp;was removed. The\u0026nbsp;three lumbar vertebrae\u0026nbsp;are processed\u0026nbsp;in turn to obtain models of\u0026nbsp;the\u0026nbsp;vertebrae and cancellous bone parts, and the models\u0026nbsp;are stored\u0026nbsp;as part\u0026nbsp;of the\u0026nbsp;STEP files. The\u0026nbsp;parts in\u0026nbsp;SolidWorks are assembled\u0026nbsp;to form an assembly. The intervertebral disc is generated between adjacent vertebral bodies through the \u0026quot;boss feature\u0026quot;, and endplates with a thickness of 1 millimeter are created on the upper and lower surfaces.\u0026nbsp;The\u0026nbsp;intervertebral disc, which is composed of the annulus fibrosus and nucleus pulposus, lies between the upper and lower endplates. First, the nucleus pulposus\u0026nbsp;was added\u0026nbsp;between the upper and lower endplates. The nucleus pulposus is modeled as an incompressible liquid-filled cavity. Then,\u0026nbsp;four 1.5 mm thick concentric rings around the nucleus pulposus\u0026nbsp;were added\u0026nbsp;to form the annulus fibrosus. The fibers of the annulus fibrosus are composed of rod-like elements that can only bear tension. The fibers move in a scissor-like manner in the annulus fibrosus and form an average angle of 25\u0026deg; to 40\u0026deg; with the intervertebral disc. The nucleus pulposus accounts for\u0026nbsp;approximately\u0026nbsp;44% of the volume of the intervertebral disc. The center of the nucleus pulposus is located\u0026nbsp;approximately\u0026nbsp;3.5 millimeters behind the center of the intervertebral disc.\u0026nbsp;The\u0026nbsp;articular cartilage between the upper and lower facet joints\u0026nbsp;was constructed\u0026nbsp;through \u0026quot;drawing sketches, stretching bosses and combinations\u0026quot;.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2 Establishment of\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003ethe\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003earticular process resection model\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eOn the basis of\u0026nbsp;the normal three-dimensional finite element model of L3--L5, according to the intraoperative situation, SolidWorks software\u0026nbsp;was used\u0026nbsp;to simulate the surgical process, and an 8.5\u0026nbsp;mm\u0026nbsp;trephine\u0026nbsp;was used\u0026nbsp;to resect the facet joints to different degrees to establish the following three-dimensional finite element models:\u003c/p\u003e\n\u003cp\u003e①\u0026nbsp;Unected\u0026nbsp;model (Model 0, M0, Fig.\u0026nbsp;1a);\u003c/p\u003e\n\u003cp\u003e②\u0026nbsp;Superior\u0026nbsp;facet joint apex foraminoplasty model\u0026nbsp;(Model 1, M1, Fig.\u0026nbsp;1b);\u003c/p\u003e\n\u003cp\u003e③\u0026nbsp;The ventral 1/3 foraminoplasty model of the superior facet joint\u0026nbsp;(Model 2, M2, Fig.\u0026nbsp;1c);\u003c/p\u003e\n\u003cp\u003e④\u0026nbsp;The ventral 1/2 foraminoplasty model of the superior facet joint\u0026nbsp;(Model 3, M3, Fig.\u0026nbsp;1d);\u003c/p\u003e\n\u003cp\u003e⑤\u0026nbsp;The ventral 2/3 foraminoplasty model of the superior facet joint\u0026nbsp;(Model 4, M4, Fig.\u0026nbsp;1e);\u003c/p\u003e\n\u003cp\u003e⑥\u0026nbsp;Ventral\u0026nbsp;3/4 foraminoplasty model of the superior facet joint\u0026nbsp;(Model 5, M5, Fig.\u0026nbsp;1f);\u003c/p\u003e\n\u003cp\u003e⑦ Model of complete resection of the superior facet joint (Model 6, M6; Fig. 1g).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3 Building a complete model\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe complete three-dimensional finite element model is imported into ANSYS 21.0 for finite element analysis. Spring elements with nonlinear material properties are used to construct ligaments (Fig. 2a), including\u0026nbsp;the\u0026nbsp;anterior longitudinal ligament (ALL), posterior longitudinal ligament (PLL), ligamentum flavum (LF), interspinous ligament (ISL), supraspinous ligament (SSL), capsular ligament (CL), and intertransverse ligament (ITL). According to the literature, the material properties in Table 1 are assigned to each ligament and structure in the material library, including\u0026nbsp;the\u0026nbsp;cortical bone, cancellous bone, nucleus pulposus, annulus fibrosus, endplate, and articular cartilage. The contact type between the facet joint cartilage and the vertebral surface is set as \u0026quot;No\u0026nbsp;separation\u0026quot;, and the contact gap range of the facet joint cartilage surface is set to 0.1 mm. The contact between the surface of the lumbar intervertebral disc and the upper and lower endplates of each vertebral body is defined as the \u0026quot;bonded\u0026quot; mode. The upper and lower endplates of each vertebral body are taken as the master surface, and the upper and lower surfaces of the intervertebral disc are taken as the slave surface. Finally, the model is meshed (Fig. 2b).\u003c/p\u003e\n\u003cp\u003eTable 1\u0026nbsp;Material parameters for finite element\u0026nbsp;modeling\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eParts\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003eYoung modulus/MPa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 17.7817%;\"\u003e\n \u003cp\u003ePoisson\u0026rsquo;s ratio\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.7254%;\"\u003e\n \u003cp\u003eSectional area/mm2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eReferences\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eCortical bone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e12000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eZhang X et al. \u003csup\u003e[15]\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eCancellous bone\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eZhang X et al. \u003csup\u003e[15]\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eCartilage endplate\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e1000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eBereczki F et al. \u003csup\u003e[16]\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eAnnulus fiber\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eZhang Q et al. \u003csup\u003e[17]\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eNucleus pulposus\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.499\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eZhang Q et al. \u003csup\u003e[17]\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eArticular facet joints\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eWu W et al. \u003csup\u003e[8]\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eALL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e60\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003eHuang S et al. \u003csup\u003e[18]\u003c/sup\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003ePLL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eLF\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e19.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eSSL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eISL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eITL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 22.7113%;\"\u003e\n \u003cp\u003eCL\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 22.3592%;\"\u003e\n \u003cp\u003e7.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 16.1972%;\"\u003e\n \u003cp\u003e0.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 18.3099%;\"\u003e\n \u003cp\u003e67.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 20.4225%;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003cstrong\u003e2.4 Boundary conditions and load settings\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhen the model is in a neutral position, the bottom of L5 is subject to fixed constraints, whereas the upper surface of the L3 vertebral body, where pressure and torque are applied, is unconstrained (Fig. 3). When the magnitude and direction of the load are set, a \u0026quot;component\u0026quot; is selected to set the load, the stress caused by the human body weight on the lumbar spine under different conditions is simulated, and the load is evenly transferred to the nodes on the surface. Pressure and torque are applied to the upper surface of the L3 vertebral body. The pressure and torque during flexion are 1175 N and 7.5 N\u0026middot;m, respectively; the pressure and torque during extension are 500 N and 7.5 N\u0026middot;m, respectively; the pressure and torque during lateral flexion are 700 N and 7.8 N\u0026middot;m, respectively; and the pressure and torque during rotation are 720 N and 5.5 N\u0026middot;m, respectively [19-21].\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.5 Observation indicators\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe movement of the lumbar spine was simulated under six working conditions: forward flexion, backward extension, left and right lateral bending, and left and right rotation. The changes in the von Mises stress of L3, L4, and L5 in the seven models were observed, the changes in the von Mises stress of the L4\u0026ndash;5 and L4\u0026ndash;5 intervertebral discs were measured, and the changes in the von Mises stress of the articular cartilage between the facet joints on both sides of L4\u0026ndash;5 were observed.\u003c/p\u003e"},{"header":"3. Results","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Model validation\u003c/h2\u003e \u003cp\u003eDifferent loading directions, such as flexion, extension, left/right bending, and left/right rotation, are applied to the vertebral body model to obtain the range of motion data of the L3\u0026ndash;L5 segment. The results are compared with the biomechanical experimental data of previous studies [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] and show good consistency (Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e). This confirms the accuracy and reliability of the model and proves its suitability for subsequent simulation studies.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.2 von Mises stress changes in the L4 vertebral body\u003c/h2\u003e \u003cp\u003eIn the L4 vertebral body, when the resection of the superior facet joint exceeds 1/2, the von Mises stress of the vertebral body under the six working conditions increases significantly. The maximum stress is the largest during forward flexion and the smallest during backward extension. Under other working conditions, the maximum stress of the vertebral body is essentially the same. The maximum stresses of the L4 vertebral body under the six load conditions are 45.334, 19.319, 27.038, 27, 27.786 and 27.796 MPa, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.3 von Mises stress changes in the L3 and L5 vertebral bodies\u003c/h2\u003e \u003cp\u003eIn the L3 and L5 vertebral bodies, when the degree of facet joint resection exceeds 1/2, the von Mises stress of both vertebral bodies increases, and the greater the degree of resection is, the greater the stress. However, the increase in amplitude is not as obvious as that of the L3 vertebral body. Under six load conditions, the maximum stresses of the L3 vertebral body are 23.232, 9.8931, 13.841, 13.846, 14.239 and 14.239 MPa, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb), and the maximum stresses of the L5 vertebral body are 17.097, 7.2774, 10.186, 10.187, 10.477 and 10.478 MPa, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec). Among the different movement states, the stress increase is most obvious during forward flexion, and the impact on adjacent vertebral bodies is the smallest during backward extension.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003e3.4 von Mises stress changes in the intervertebral disc\u003c/h2\u003e \u003cp\u003eIn the L3-4 intervertebral disc, when the degree of facet joint resection exceeds 1/2, the von Mises stress of the intervertebral disc increases. The maximum stress is 1.5705 MPa, and the minimum stress is 0.66901 MPa. Under six load conditions, the maximum stresses of the L3-4 intervertebral disc are 1.5705, 0.66901, 0.93636, 0.93549, 0.96271 and 0.96262 MPa, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed).\u003c/p\u003e \u003cp\u003eIn the L4-5 intervertebral disc, as the resection volume continues to increase, the von Mises stress of the intervertebral disc tends to decrease overall. Under six load conditions, the minimum stresses of the L4-5 intervertebral disc are 1.5492, 0.65981, 0.92367, 0.92271, 0.94966 and 0.94948 MPa, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ee).\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003e3.5 von Mises stress changes in L3\u0026ndash;L4 articular cartilage\u003c/h2\u003e \u003cp\u003eWhen the degree of facet joint resection exceeds 1/2, the von Mises stress of the articular cartilage on both sides increases significantly. The maximum stress on the left side is 49.739 MPa, and the minimum stress is 20.029 MPa. The maximum stress on the right side is 21.021 MPa, and the minimum stress is 7.15 MPa. Under six load conditions, the maximum stresses of the left facet joint of L3-4 are 49.739, 21.2, 29.665, 29.627, 30.494 and 30.492 MPa, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ef), and the maximum stresses of the right facet joint are 21.021, 8.9671, 12.522, 12.544, 12.887 and 12.894 MPa, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eg). When the two sides are compared, the stress of the articular cartilage on the right side of each model is significantly lower than that on the left side, and the stress change shows an asymmetric trend.\u003c/p\u003e \u003c/div\u003e"},{"header":"4. Discussion","content":"\u003cp\u003eLumbar disc herniation is a common spinal disease that often leads to a series of clinical symptoms, such as low back pain, numbness and pain in one lower limb or both lower limbs. When nonsurgical treatment is ineffective, surgical treatment should be considered. Percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID) are currently the most common minimally invasive surgical methods for treating lumbar disc herniation [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. During PETD, depending on the size of the patient's intervertebral foramen and the location of the intervertebral disc herniation, foraminal plasty on one side is generally required to enlarge the intervertebral foramen. This process damages the facet joints and the articular cartilage to varying degrees, which may cause iatrogenic instability and accelerate degeneration [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. At present, most lumbar disc herniations occur in the L4‒5 and L5‒S1 segments, and relatively few studies have investigated lumbar biomechanics after L3‒4 segment lumbar disc herniation surgery. Therefore, we used the CT scan data of the lumbar spine segments of volunteers to establish a finite element model and seven models to simulate possible situations during the operation.\u003c/p\u003e \u003cp\u003eAn analysis of the seven models revealed that when the degree of resection of the superior facet joint during foraminaloplasty exceeds 1/2, the stresses on the L3, L4 and L5 vertebral bodies under the six working conditions all increase significantly, and the greater the resection volume is, the greater the stress. The increase in stress is the greatest during forward flexion, and the increase in stress is the smallest during backward extension. The increased stress in the vertebral body during left/right lateral flexion and left/right rotation is essentially the same. This finding indicates that extensive resection of the facet joint may increase the degree of degeneration of the responsible segment and adjacent segment vertebral bodies. Shi et al. [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e] reported that when a 15 mm endoscope is used to resect the superior facet joint, the surgical segment increases significantly during backward extension, right flexion, and left and right rotations. The adjacent segment only increases slightly during backward extension. After resection with a 7.5 mm or 10 mm endoscope, the pressure applied to the adjacent segment vertebral body was similar to that applied to the unresected vertebral body. Therefore, the greater the resection volume of the superior facet joint is, the greater the impact on the adjacent segment vertebral body.\u003c/p\u003e \u003cp\u003eWu et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] reported significant stress differences in the intervertebral discs of surgical segments, whereas no obvious stress changes were observed in the intervertebral discs of adjacent segments. This study revealed that when the degree of resection of the superior facet joint exceeds 1/2, the stress on the L3-4 intervertebral disc in the seven models increases. However, in the L4-5 intervertebral disc, as the resection volume of the facet joint increases, the stress of the intervertebral disc gradually decreases. This finding indicates that extensive resection of the facet joint may increase degeneration of the intervertebral disc in the responsible segment but has no obvious effect on the intervertebral disc in the adjacent segment. Shi et al. [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] reported that when S1 superior facet joint foraminoplasty is greater than 3/5, the stress of the intervertebral disc in the surgical segment significantly increases in most movement directions, which is similar to our research results.\u003c/p\u003e \u003cp\u003eWhen the degree of resection of the articular process of the superior articular joint exceeds 1/2, the stress on the articular cartilage on both sides increases significantly. Moreover, the stress increase amplitude of the articular cartilage on the left side is greater than that on the right side. The stress on both sides shows an asymmetric change. The greater the forming amplitude is, the greater the stress on the contralateral articular cartilage. This may lead to long-term effects such as degenerative scoliosis. This suggests that when performing facet joint foraminoplasty, it is best to be close to the medial side and reduce the grinding of the facet joint as much as possible on the premise of sufficient decompression. Wu et al. [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] reported that after L4/5 foraminal plasty, the stresses of the L3/4 and L5/S1 facet joints decreased, whereas the stresses of the L4/5 facet joints generally tended to increase. Significant asymmetric stress changes in the bilateral facet joints were observed in all three segments, especially during bilateral rotational movements, suggesting that unnecessary and excessive resection should be avoided in PTED to reduce the incidence of low back pain and the risk of postoperative degeneration. Some studies have shown that, compared with resection alone, simultaneous resection of the tip and base of the superior articular process increases the stress on the facet joints in various motion states. Some studies have shown that under forward flexion and right lateral flexion, the increase in facet joint stress caused by resection of the tip of the superior articular process is smaller than that when the base is resected, whereas the opposite result is found under left lateral flexion, backward extension and rotation [\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. In this study, we found that when the articular cartilage is not damaged, the stress of the facet joint does not significantly change and has little impact on spinal stability. This finding indicates that when performing foraminal plasty, damage to the articular cartilage should be avoided as much as possible.\u003c/p\u003e \u003cp\u003eThis study also has the following shortcomings. First, the finite element model established in this study simplifies the muscles connected to the lumbar spine and the weight of the upper body, and there is still a certain difference from the real human body. Second, factors associated with the annulus fibrosus, such as annulus fibrosus damage, reduced nucleus pulposus volume, and endplate damage caused by intervertebral disc resection, are not considered. Moreover, the formation of scar tissue in the surgical area and the ingrowth of new bone tissue after surgery also have a certain impact on the stability of the lumbar spine. Third, the finite element model analysis in this study is a one-time load study and cannot systematically analyze the impact of fatigue loading on the biomechanics of the lumbar spine. Although the spinal finite element model is increasingly in line with human anatomy compared with previous designs, more refinements are still needed to obtain more accurate shapes and physical properties to increase the biomechanical application range of personalized finite element spinal models.\u003c/p\u003e"},{"header":"5. Conclusions","content":"\u003cp\u003eIn this study, a normal L3‒L5 segment finite element model was established; on this basis, a facet joint tip foraminoplasty model, a 1/3 facet joint foraminoplasty model, a 1/2 facet joint foraminoplasty model, a 2/3 facet joint foraminoplasty model, a 3/4 facet joint foraminoplasty model and a complete resection model of the superior facet joint were established. The model is successfully verified, the prediction results are credible, and the model can be used for biomechanical analysis and surgical condition simulation. When facet joint foraminoplasty under the combined action of large-channel endoscopy and visualized trephine exceeds 1/2, it increases the stress of the vertebral body, intervertebral disc and facet joint of the surgical segment, causes asymmetric stress on the facet joints on both sides, and may cause iatrogenic instability; however, it does not cause degeneration of the intervertebral disc in adjacent segments.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eLDH\u0026nbsp;Lumbar\u0026nbsp;disc herniation\u003c/p\u003e\n\u003cp\u003ePETD \u0026nbsp;Percutaneous\u0026nbsp;endoscopic transforaminal discectomy\u003c/p\u003e\n\u003cp\u003eROM \u0026nbsp;Range\u0026nbsp;of\u0026nbsp;motion\u003c/p\u003e\n\u003cp\u003eFEA \u0026nbsp;Finite Element Analysis\u003c/p\u003e\n\u003cp\u003eDICOM \u0026nbsp;Digital Imaging and Communications in Medicine\u003c/p\u003e\n\u003cp\u003ePEID \u0026nbsp;Percutaneous endoscopic interlaminar discectomy\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Informed consent was obtained from all individual participants included in the study. The Affiliated Hospital of Xuzhou Medical University Ethics Committee reviewed and approved the study protocol.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data used to support the findings of this study are included within the article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study was support by the Xuzhou Young Reserve Medical Talent Development Project (XWRCHT20220038) and the Xuzhou Science and Technology Project (KC21210).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors' contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eD.L. and H.F. carried out the model development and simulation, data analysis and drafted the manuscript. W.S., S.Z., D.W., X.G. participated in the study design. D.L., H.F., S.Z., W.S. participated in revising the manuscript. W.S. and H.F. devised the concept and supervised the study. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eZhang B, He Z, Guo J, Li F, Huang Z, Zheng W, Xing W, Li M, Zhu Y, Yang X. Sesamin-mediated high expression of \u003cem\u003eBECN2\u003c/em\u003e ameliorates cartilage endplate degeneration by reducing autophagy and inflammation. Aging (Albany NY). 2024 Jan 26;16(2):1145-1160. doi: 10.18632/aging.205386. Epub 2024 Jan 26. \u003c/li\u003e\n\u003cli\u003eLinhardt O, Grifka J, Benditz A. Besteht ein Zusammenhang zwischen der degenerativen Bandscheibenver\u0026auml;nderung und dem Auftreten von lumbalen Bandscheibenvorf\u0026auml;llen? 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LUMBAR DISC HERNIATION. Rev Bras Ortop. 2015 Nov 16;45(1):17-22. doi: 10.1016/S2255-4971(15)30211-1. \u003c/li\u003e\n\u003cli\u003eWang R, Wu Z. Recent advancement in finite element analysis of spinal interbody cages: A review. Front Bioeng Biotechnol. 2023 Mar 23;11:1041973. doi: 10.3389/fbioe.2023.1041973. \u003c/li\u003e\n\u003cli\u003eRitzel H, Amling M, P\u0026ouml;sl M, Hahn M, Delling G. The thickness of human vertebral cortical bone and its changes in aging and osteoporosis: a histomorphometric analysis of the complete spinal column from thirty-seven autopsy specimens. J Bone Miner Res. 1997 Jan;12(1):89-95. doi: 10.1359/jbmr.1997.12.1.89.\u003c/li\u003e\n\u003cli\u003eZhang X, Chen T, Meng F, Li S, Xu G, Yan J, Zhao W. A finite element analysis on different bone cement forms and injection volumes injected into lumbar vertebral body in percutaneous kyphoplasty. 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Pain Physician. 2020 Jan;23(1):49-56. PMID: 32013278.\u003c/li\u003e\n\u003cli\u003eSun W, Li D, Zhao S, Fu H, Tian J, Zhang F, Feng H, Wu D. The effect of large channel-based foraminoplasty on lumbar biomechanics in percutaneous endoscopic discectomy: a finite element analysis. J Orthop Surg Res. 2024 Jul 12;19(1):402. doi: 10.1186/s13018-024-04870-1. \u003c/li\u003e\n\u003cli\u003eShi Y, Xie YZ, Zhou Q, Yu Y, Fan XH. The biomechanical effect of the relevant segments after facet-disectomy in different diameters under posterior lumbar percutaneous endoscopes: a three-dimensional finite element analysis. J Orthop Surg Res. 2021 Oct 14;16(1):593. doi: 10.1186/s13018-021-02733-7. \u003c/li\u003e\n\u003cli\u003eWu Z, Sun H, Zhang Y, Xiao L, Zhao Q. Biomechanical Finite Element Analysis of Percutaneous Endoscopic Lumbar Discectomy via a Transforaminal Approach. World Neurosurg. 2024 May;185:e291-e298. doi: 10.1016/j.wneu.2023.10.108. \u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Lumbar disc herniation, Biomechanical, Foraminoplasty, Visible trephine, Finite element","lastPublishedDoi":"10.21203/rs.3.rs-5411592/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-5411592/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose:\u003c/strong\u003e This study aimed to evaluate the effect of the degree of facet joint resection under the combined action of large-channel endoscopy and visualized trephines on lumbar biomechanics.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods:\u003c/strong\u003e The original CT data of a healthy male volunteer were selected. An L3-5 lumbar spine model, M0,was established via thethree-dimensional finite element method. Different degrees of resection of the superior articular process of L4 were simulated via a visualized trephine during the operation, and six models were established (M1: tip resection; M2: resection of the ventral 1/3; M3: resection of the ventral 1/2; M4: resection of the ventral 2/3; M5: resection of the ventral 3/4; and M6: complete resection). Loads were applied to the model to simulate six motions of flexion, extension, left/right lateral bending, and left/right rotation. The stress distributions of the vertebral body, intervertebral disc and articular cartilage of the L3-4 segment and adjacent segments wereobserved.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e When the degree of facet joint resection does not exceed 1/2, there is no significant change in the pressure of the vertebral body, intervertebral disc and facet joint in M1, M2 and M3. When the degree of facet joint resection exceeds 1/2, the pressure on the L3, L4 and L5 vertebral bodies in models M4, M5 and M6 increases significantly. The pressure of the L3-4 intervertebral disc increases while the pressure of the L4-5 intervertebral disc tends to decrease. The pressure of the facet joints on both sides of L3-4 increases, and the pressure increase on the left facet joint is relatively large.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e When more than half of the superior articular process of L4 is resected under large-channel endoscopy, the stress on the vertebral body, intervertebral disc and articular cartilage of the L3-4 segment increases, which may cause iatrogenic instability but has no significant effect on the stress on the vertebral body or intervertebral disc of adjacent segments.\u003c/p\u003e","manuscriptTitle":"The effect of large-channel endoscopy combined with visualization of trephines for foraminoplasty on lumbar biomechanics: a finite element analysis","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-11-26 16:01:41","doi":"10.21203/rs.3.rs-5411592/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"554d2dc8-8255-4552-9a95-4bd98f41f7d0","owner":[],"postedDate":"November 26th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-03-04T11:26:38+00:00","versionOfRecord":[],"versionCreatedAt":"2024-11-26 16:01:41","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-5411592","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-5411592","identity":"rs-5411592","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}