{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T09:28:11Z","timestamp":1786613291719,"version":"build-2736575974"},"reference-count":34,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T00:00:00Z","timestamp":1786579200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Bioeng. Biotechnol."],"abstract":"<jats:sec>\n                    <jats:title>Purpose<\/jats:title>\n                    <jats:p>This finite element study aimed to quantitatively compare the biomechanical properties of translaminar lag screws with different diameters and structural designs for the surgical repair of L5 bilateral spondylolysis, to provide evidence for individualized screw selection.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Methods<\/jats:title>\n                    <jats:p>An intact model of L4-S1 segment (Model A) and a L5 bilateral spondylolysis model (Model B) were established using Mimics, Geomagic, and SolidWorks. Additional models were constructed incorporating translaminar lag screws of varying diameters: 4.5\u00a0mm (solid, Model C1; cannulated, Model C2), 4.0\u00a0mm (solid, Model D1; cannulated, Model D2), and 3.5\u00a0mm (solid, Model E1; cannulated, Model E2). Following model validation, a 400\u00a0N axial load and a 10\u00a0N\u00a0m moment were applied to simulate five conditions. Analyzed parameters included range of motion (ROM), maximum displacement, and maximum von Mises stress in the disc, pars interarticularis, and fixation screws.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Results<\/jats:title>\n                    <jats:p>Compared to the intact model (A), the spondylolysis model (B) showed significant instability. All fixation models (C1-E2) effectively restored ROM to intact levels, regardless of screw diameter or structural design. Larger-diameter (4.5\u00a0mm) and solid designs demonstrated slightly better control of model displacement. Increasing diameter significantly reduced stress concentrations within the pars interarticularis and fixation screws. For a given diameter, cannulated screws sustained higher stress than solid screws. The 3.5\u00a0mm cannulated screw exhibited the highest screw stress, approaching the yield strength of titanium alloy under rotational loading.<\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>Conclusion<\/jats:title>\n                    <jats:p>All translaminar lag screw designs can effectively restore stability in L5 spondylolysis. While different diameters and structural designs have a minor impact on stability restoration, they significantly affect implant stress. In this specific patient-derived model, the 4.5\u00a0mm solid screw demonstrated the most favorable biomechanical profile, with the lowest stress on the implant and effective control of graft displacement. These findings suggest a potential mechanical advantage for 4.5\u00a0mm solid screws; however, confirmation through multi-specimen studies or clinical trials is required before broader clinical recommendations can be made.<\/jats:p>\n                  <\/jats:sec>","DOI":"10.3389\/fbioe.2026.1882221","type":"journal-article","created":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T08:43:33Z","timestamp":1786610613000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Three-dimensional finite element analysis of translaminar lag screw designs for L5 bilateral spondylolysis"],"prefix":"10.3389","volume":"14","author":[{"given":"Feng","family":"Li","sequence":"first","affiliation":[{"name":"Department of Spine Surgery, The 940th Hospital of Joint Logistic Support Force of Chinese People\u2019s Liberation Army","place":["Lanzhou, Gansu, China"]},{"name":"Department of Orthopedics, Tangdu Hospital, Fourth Military Medical University","place":["Xi\u2019an, Shaanxi, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xingguo","family":"Tan","sequence":"additional","affiliation":[{"name":"Department of Spine Surgery, The 940th Hospital of Joint Logistic Support Force of Chinese People\u2019s Liberation Army","place":["Lanzhou, Gansu, China"]},{"name":"Department of Orthopedics, Shexian Hospital","place":["Handan, Hebei, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tao","family":"Zhang","sequence":"additional","affiliation":[{"name":"Department of Spine Surgery, The 940th Hospital of Joint Logistic Support Force of Chinese People\u2019s Liberation Army","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hua","family":"Liu","sequence":"additional","affiliation":[{"name":"Department of Spine Surgery, The 940th Hospital of Joint Logistic Support Force of Chinese People\u2019s Liberation Army","place":["Lanzhou, Gansu, China"]},{"name":"First Clinical Medical School, Gansu University of Chinese Medical","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Songkai","family":"Li","sequence":"additional","affiliation":[{"name":"Department of Spine Surgery, The 940th Hospital of Joint Logistic Support Force of Chinese People\u2019s Liberation Army","place":["Lanzhou, Gansu, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,8,13]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"1812","DOI":"10.1016\/j.spinee.2014.06.015","article-title":"Bilateral pedicle screw fixation provides superior biomechanical stability in transforaminal lumbar interbody fusion: a finite element study","volume":"15","author":"Ambati","year":"2015","journal-title":"Spine J."},{"key":"B2","doi-asserted-by":"publisher","first-page":"695","DOI":"10.1080\/10255842.2010.493517","article-title":"Parametric convergence sensitivity and validation of a finite element model of the human lumbar spine","volume":"14","author":"Ayturk","year":"2011","journal-title":"Comput. Methods Biomechanics Biomedical Engineering"},{"key":"B3","doi-asserted-by":"publisher","first-page":"61","DOI":"10.1097\/MOP.0000000000000706","article-title":"Spondylolysis 2019 update","volume":"31","author":"Berger","year":"2019","journal-title":"Curr. Opinion Pediatrics"},{"key":"B4","doi-asserted-by":"publisher","first-page":"270","DOI":"10.1177\/014107689108400509","article-title":"Results of buck screw fusion in grade I spondylolisthesis","volume":"84","author":"Bonnici","year":"1991","journal-title":"J. R. Soc. Med."},{"key":"B5","doi-asserted-by":"crossref","first-page":"432","DOI":"10.1302\/0301-620X.52B3.432","article-title":"Direct repair of the defect in spondylolisthesis. Preliminary report","volume":"52","author":"Buck","year":"1970","journal-title":"J. Bone Jt. Surg. Br."},{"key":"B6","doi-asserted-by":"publisher","first-page":"105","DOI":"10.1186\/s12938-017-0392-1","article-title":"Effect of different inner core diameters on structural strength of cannulated pedicle screws under various lumbar spine movements","volume":"16","author":"Chang","year":"2017","journal-title":"Biomed. Engineering Online"},{"key":"B7","doi-asserted-by":"publisher","first-page":"328","DOI":"10.1097\/00007632-199902150-00004","article-title":"Biomechanical comparison of spondylolysis fixation techniques","volume":"24","author":"Deguchi","year":"1999","journal-title":"Spine (Phila Pa 1976)"},{"key":"B8","doi-asserted-by":"publisher","first-page":"101535","DOI":"10.1016\/j.jcot.2021.101535","article-title":"Lumbar spondylolysis - current concepts review","volume":"21","author":"Debnath","year":"2021","journal-title":"J. Clinical Orthopaedics Trauma"},{"key":"B9","doi-asserted-by":"publisher","first-page":"121","DOI":"10.1177\/2192568217713008","article-title":"Predictive factors for the outcome of surgical treatment of lumbar spondylolysis in young sporting individuals","volume":"8","author":"Debnath","year":"2018","journal-title":"Glob. Spine J."},{"key":"B10","doi-asserted-by":"publisher","first-page":"766","DOI":"10.1016\/j.jbiomech.2004.07.039","article-title":"Biomechanical comparison between fusion of two vertebrae and implantation of an artificial intervertebral disc","volume":"39","author":"Denozi\u00e8re","year":"2006","journal-title":"J. Biomech."},{"key":"B11","doi-asserted-by":"publisher","first-page":"209","DOI":"10.1007\/s00402-009-0897-6","article-title":"Direct repair of spondylolysis by tsrh's hook plus screw fixation and bone grafting: biomechanical study and clinical report","volume":"130","author":"Fan","year":"2010","journal-title":"Arch. Orthop. Trauma Surg."},{"key":"B12","doi-asserted-by":"publisher","first-page":"S115","DOI":"10.1007\/s00586-011-1759-9","article-title":"Long-term results of the direct repair of spondylolisthesis","volume":"20","author":"Giudici","year":"2011","journal-title":"Eur. Spine J."},{"key":"B13","doi-asserted-by":"publisher","first-page":"182","DOI":"10.1055\/s-2007-982511","article-title":"Minimally invasive technique for direct repair of the pars defects in young adults using a spinal endoscope: a technical note","volume":"50","author":"Higashino","year":"2007","journal-title":"Minim. Invasive Neurosurg."},{"key":"B14","doi-asserted-by":"publisher","first-page":"e0166452","DOI":"10.1371\/journal.pone.0166452","article-title":"Preserving posterior complex can prevent adjacent segment disease following posterior lumbar interbody fusion surgeries: a finite element analysis","volume":"11","author":"Huang","year":"2016","journal-title":"PloS One"},{"key":"B15","doi-asserted-by":"publisher","first-page":"263","DOI":"10.1227\/neu.0000000000002210","article-title":"Percutaneous direct pars repair in young athletes","volume":"92","author":"Jamshidi","year":"2023","journal-title":"Neurosurgery"},{"key":"B16","doi-asserted-by":"publisher","first-page":"1248","DOI":"10.1016\/j.jbiomech.2016.02.050","article-title":"Characterization of the L4-L5-S1 motion segment using the stepwise reduction method","volume":"49","author":"Jaramillo","year":"2016","journal-title":"J. Biomechanics"},{"key":"B17","doi-asserted-by":"publisher","first-page":"1287","DOI":"10.1016\/j.medengphy.2008.09.006","article-title":"Finite element analysis of the spine: towards a framework of verification, validation and sensitivity analysis","volume":"30","author":"Jones","year":"2008","journal-title":"Med. Eng. Phys."},{"key":"B18","doi-asserted-by":"publisher","first-page":"E581","DOI":"10.1097\/BRS.0b013e3182463775","article-title":"Effect of graded facetectomy on biomechanics of dynesys dynamic stabilization system","volume":"37","author":"Kiapour","year":"2012","journal-title":"Spine (Phila Pa 1976)"},{"key":"B19","doi-asserted-by":"publisher","first-page":"144","DOI":"10.3340\/jkns.2009.46.2.144","article-title":"The changes in range of motion after a lumbar spinal arthroplasty with Charit\u00e9 in the human cadaveric spine under physiologic compressive follower preload: a comparative study between load control protocol and hybrid protocol","volume":"46","author":"Kim","year":"2009","journal-title":"J. Korean Neurosurg. Soc."},{"key":"B20","doi-asserted-by":"publisher","first-page":"1456","DOI":"10.1097\/BRS.0b013e31824da81d","article-title":"Effects of lumbar arthrodesis on adjacent segments: differences between surgical techniques","volume":"37","author":"Kim","year":"2012","journal-title":"Spine (Phila Pa 1976)"},{"key":"B21","first-page":"285","article-title":"My method of filing the lesion with spongy bone in spondylolysis and spondylolistesis","volume":"19","author":"Kimura","year":"1968","journal-title":"Seikei Geka"},{"key":"B22","doi-asserted-by":"publisher","first-page":"e0229328","DOI":"10.1371\/journal.pone.0229328","article-title":"Biomechanical comparison of pedicle screw fixation strength in synthetic bones: effects of screw shape, core\/thread profile and cement augmentation","volume":"15","author":"Liu","year":"2020","journal-title":"PLoS One"},{"key":"B23","doi-asserted-by":"publisher","first-page":"104","DOI":"10.1097\/BRS.0000000000000043","article-title":"Clinical results and functional outcomes after direct intralaminar screw repair of spondylolysis","volume":"39","author":"Menga","year":"2014","journal-title":"Spine (Phila Pa 1976)"},{"key":"B24","doi-asserted-by":"publisher","first-page":"E469","DOI":"10.1097\/BRS.0000000000000818","article-title":"Does location of rotation center in artificial disc affect cervical biomechanics?","volume":"40","author":"Mo","year":"2015","journal-title":"Spine (Phila Pa 1976)"},{"key":"B25","doi-asserted-by":"publisher","first-page":"100284","DOI":"10.1016\/j.xnsj.2023.100284","article-title":"New technique and case report: robot-assisted intralaminar screw fixation of spondylolysis in an adolescent","volume":"16","author":"Narendran","year":"2023","journal-title":"N. Am. Spine Soc. J."},{"key":"B26","doi-asserted-by":"publisher","first-page":"57","DOI":"10.1111\/j.1757-7861.2010.00112.x","article-title":"Study of stress distribution in pedicle screws along a continuum of diameters: a three-dimensional finite element analysis","volume":"3","author":"Qi","year":"2011","journal-title":"Orthop. Surgery"},{"key":"B27","doi-asserted-by":"publisher","first-page":"285","DOI":"10.1016\/0141-5425(82)90045-0","article-title":"Three dimensional surgical simulations of the spine","volume":"4","author":"Ranu","year":"1982","journal-title":"J. Biomed. Eng."},{"key":"B28","doi-asserted-by":"publisher","first-page":"1020","DOI":"10.1016\/j.clinbiomech.2006.06.011","article-title":"Buck's direct repair of lumbar spondylolysis restores disc stresses at the involved and adjacent levels","volume":"21","author":"Sairyo","year":"2006","journal-title":"Clin. Biomech. (Bristol, Avon)"},{"key":"B29","doi-asserted-by":"publisher","first-page":"329","DOI":"10.3171\/2014.5.SPINE13772","article-title":"Spondylolysis outcomes in adolescents after direct screw repair of the pars interarticularis","volume":"21","author":"Snyder","year":"2014","journal-title":"J. Neurosurg. Spine"},{"key":"B30","doi-asserted-by":"publisher","first-page":"517","DOI":"10.1111\/os.12877","article-title":"Biomechanical evaluation of oblique lumbar interbody fusion with various fixation options: a finite element analysis","volume":"13","author":"Song","year":"2021","journal-title":"Orthop. Surg."},{"key":"B31","doi-asserted-by":"publisher","first-page":"415","DOI":"10.1136\/bjsm.34.6.415","article-title":"Spondylolysis: a critical review","volume":"34","author":"Standaert","year":"2000","journal-title":"Br. Journal Sports Medicine"},{"key":"B32","doi-asserted-by":"publisher","first-page":"e18944","DOI":"10.1097\/MD.0000000000018944","article-title":"Robot-assisted direct repair of spondylolysis: a case report","volume":"99","author":"Tian","year":"2020","journal-title":"Med. Baltim."},{"key":"B33","doi-asserted-by":"publisher","first-page":"1024159","DOI":"10.3389\/fbioe.2022.1024159","article-title":"Biomechanical evaluation of lumbar spondylolysis repair with various fixation options: a finite element analysis","volume":"10","author":"Ye","year":"2022","journal-title":"Front. Bioeng. Biotechnol."},{"key":"B34","doi-asserted-by":"publisher","first-page":"e447","DOI":"10.1016\/j.wneu.2021.04.061","article-title":"Biomechanical changes of adjacent and fixed segments through cortical bone trajectory screw fixation versus traditional trajectory screw fixation in the lumbar spine: a finite element analysis","volume":"151","author":"Zhang","year":"2021","journal-title":"World Neurosurgery"}],"container-title":["Frontiers in Bioengineering and Biotechnology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fbioe.2026.1882221\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,8,13]],"date-time":"2026-08-13T08:43:34Z","timestamp":1786610614000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fbioe.2026.1882221\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,8,13]]},"references-count":34,"alternative-id":["10.3389\/fbioe.2026.1882221"],"URL":"https:\/\/doi.org\/10.3389\/fbioe.2026.1882221","relation":{},"ISSN":["2296-4185"],"issn-type":[{"value":"2296-4185","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,8,13]]},"article-number":"1882221"}}