{"id":{"repo_id":"uwo","oai_identifier":"oai:uwo.scholaris.ca:20.500.14721/36576"},"canonical_url":"https://search.dev.ndltd.org/etd/uwo/oai:uwo.scholaris.ca:20.500.14721/36576","repository":{"repo_id":"uwo","name":"Western University","base_url":"https://uwo.scholaris.ca/server/oai/request"},"display":{"title":"Design and Development of a Novel Expanding Pedicle Screw for Use in the Osteoporotic Lumbar Spine","abstract":"Pedicle screws are commonly utilized in spinal surgery; however, traditional designs often do not provide adequate fixation in osteoporotic spines. The objective of this thesis was to develop a novel expanding screw for use in osteoporotic lumbar pedicles. Helical screws capable of expanding post insertion were built on a rapid prototype machine. A materials testing machine performed axial load to failure tests in both Sawbones and cadaveric specimens comparing the new design to traditional screws (rate = 10mm/min to 20 mm). Output parameters included yield load, ultimate load, stiffness, energy to failure and total energy. The expanding screw showed a 36% increase in total energy (p=0.02), but no other differences were identified. Based on this initial design, the expandable pedicle screws failed to demonstrate improved screw pullout; however, differences may be observed in other loading modes (i.e., toggle) and further design modifications and improvements in post-build machining may provide beneficial enhancements.","abstract_html":"Pedicle screws are commonly utilized in spinal surgery; however, traditional designs often do not provide adequate fixation in osteoporotic spines. The objective of this thesis was to develop a novel expanding screw for use in osteoporotic lumbar pedicles. Helical screws capable of expanding post insertion were built on a rapid prototype machine. A materials testing machine performed axial load to failure tests in both Sawbones and cadaveric specimens comparing the new design to traditional screws (rate = 10mm/min to 20 mm). Output parameters included yield load, ultimate load, stiffness, energy to failure and total energy. The expanding screw showed a 36% increase in total energy (p=0.02), but no other differences were identified. Based on this initial design, the expandable pedicle screws failed to demonstrate improved screw pullout; however, differences may be observed in other loading modes (i.e., toggle) and further design modifications and improvements in post-build machining may provide beneficial enhancements.","abstract_has_math":false,"creators":["Rasoulinejad, Parham"],"institution":"The University of Western Ontario","degree_name":"M Sc","degree_level":null,"degree_discipline":"Medical Biophysics","degree_department":null,"school":null,"contributors":[],"advisors":["Bailey, Chris"],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-08-23","date_published":"2013-08-23","updated_at":"2026-07-27T21:56:13Z","subjects":["spine","biomechanics","implant fixation","mechanical testing","pedicle screws","osteoporosis","pullout strength","expanding screws"],"languages":["en_ca"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/20.500.14721/36576","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Bailey, Chris"]},{"key":"dc:creator","label":"Author","values":["Rasoulinejad, Parham"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2025-07-10T21:23:29Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2025-07-10T21:23:29Z"]},{"key":"dc:date.issued","label":"Date","values":["2013-08-23"]},{"key":"dc:publisher","label":"Institution","values":["The University of Western Ontario"]},{"key":"dc:type","label":"Dc Type","values":["thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Medical Biophysics"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M Sc"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["spine","biomechanics","implant fixation","mechanical testing","pedicle screws","osteoporosis","pullout strength","expanding screws"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_ca"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/20.500.14721/36576"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."]},{"key":"dc:description.abstract","label":"Abstract","values":["Pedicle screws are commonly utilized in spinal surgery; however, traditional designs often do not provide adequate fixation in osteoporotic spines. The objective of this thesis was to develop a novel expanding screw for use in osteoporotic lumbar pedicles. Helical screws capable of expanding post insertion were built on a rapid prototype machine. A materials testing machine performed axial load to failure tests in both Sawbones and cadaveric specimens comparing the new design to traditional screws (rate = 10mm/min to 20 mm). Output parameters included yield load, ultimate load, stiffness, energy to failure and total energy. The expanding screw showed a 36% increase in total energy (p=0.02), but no other differences were identified. Based on this initial design, the expandable pedicle screws failed to demonstrate improved screw pullout; however, differences may be observed in other loading modes (i.e., toggle) and further design modifications and improvements in post-build machining may provide beneficial enhancements."]},{"key":"dc:title","label":"Title","values":["Design and Development of a Novel Expanding Pedicle Screw for Use in the Osteoporotic Lumbar Spine"]}]}],"canonical_facts":{"dc:contributor.advisor":["Bailey, Chris"],"dc:creator":["Rasoulinejad, Parham"],"dc:date.accessioned":["2025-07-10T21:23:29Z"],"dc:date.available":["2025-07-10T21:23:29Z"],"dc:date.issued":["2013-08-23"],"dc:description":["The thesis cover page in the PDF document includes references to Western University’s previous institutional repository platform, known as Scholarship@Western, and links to that platform (beginning with ir.lib.uwo.ca). In citing or referring to this thesis, use the DOI or handle from this page instead. Sample citation: Author name, \"Thesis title.\" (Year). Western University Open Repository. https://doi.org/10.71858/123456."],"dc:description.abstract":["Pedicle screws are commonly utilized in spinal surgery; however, traditional designs often do not provide adequate fixation in osteoporotic spines. The objective of this thesis was to develop a novel expanding screw for use in osteoporotic lumbar pedicles. Helical screws capable of expanding post insertion were built on a rapid prototype machine. A materials testing machine performed axial load to failure tests in both Sawbones and cadaveric specimens comparing the new design to traditional screws (rate = 10mm/min to 20 mm). Output parameters included yield load, ultimate load, stiffness, energy to failure and total energy. The expanding screw showed a 36% increase in total energy (p=0.02), but no other differences were identified. Based on this initial design, the expandable pedicle screws failed to demonstrate improved screw pullout; however, differences may be observed in other loading modes (i.e., toggle) and further design modifications and improvements in post-build machining may provide beneficial enhancements."],"dc:identifier.uri":["https://hdl.handle.net/20.500.14721/36576"],"dc:language.iso":["en_ca"],"dc:publisher":["The University of Western Ontario"],"dc:subject":["spine","biomechanics","implant fixation","mechanical testing","pedicle screws","osteoporosis","pullout strength","expanding screws"],"dc:title":["Design and Development of a Novel Expanding Pedicle Screw for Use in the Osteoporotic Lumbar Spine"],"dc:type":["thesis"],"thesis:degree_discipline":["Medical Biophysics"],"thesis:degree_name":["M Sc"]},"updated_at":"2026-07-27T21:56:13Z"}