{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T12:53:50Z","timestamp":1781528030153,"version":"3.54.1"},"reference-count":36,"publisher":"Ovid Technologies (Wolters Kluwer Health)","issue":"7","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2016,8]]},"abstract":"\n Study Design:<\/jats:title>\n Expansive pedicle screws (EPS) and polymethylmethacrylate-augmented pedicle screws (PMMA-PS) were inserted into osteoporotic synthetic bones, which were then tested by radiographic and biomechanical examinations.<\/jats:p>\n <\/jats:sec>\n \n Objective:<\/jats:title>\n To compare the stability of EPS and PMMA-PS with that of a conventional pedicle screw (CPS) in an osteoporotic synthetic bone.<\/jats:p>\n <\/jats:sec>\n \n Summary of Background Data:<\/jats:title>\n It is a significant challenge for orthopedic surgeons performing transpedicular fixation in the osteoporotic spine. Prior studies have suggested that both EPS and PMMA-PS can increase the screw stability effectively. However, there are no biomechanical comparisons of EPS and PMMA-PS, especially in primary spinal surgery in osteoporosis.<\/jats:p>\n <\/jats:sec>\n \n Methods:<\/jats:title>\n Thirty osteoporotic synthetic bone blocks were divided into 3 groups randomly. A pilot hole was prepared in advance in all samples by the same method. Then, the CPS was inserted directly into the pilot hole in the CPS group; the hole in the PMMA-PS group was first filled with polymethylmethacrylate (PMMA; 2.5 mL) and then inserted with CPS, and the EPS was inserted directly into the blocks in the EPS group. Twenty-four hours later, x-ray and computed tomography examination and axial pullout tests were performed on all samples; the block destructions were then recorded, and the hole diameters were measured.<\/jats:p>\n <\/jats:sec>\n \n Results:<\/jats:title>\n In the CPS group, the screw was surrounded directly by the synthetic bone without any other materials, whereas in the PMMA-PS group, the screw was totally wrapped up by PMMA, and the PMMA was evenly distributed in the synthetic bone around the screw, indicating obvious improvement of the local density around the track. In the EPS group, the anterior part of the EPS presented an obvious expansion in synthetic bone and formed an unguiform structure pressing the surrounding synthetic bone. Screw stabilities in both the PMMA-PS and the EPS groups were significantly enhanced compared with those in the CPS group, and the screw stability in the PMMA-PS group was significantly higher than that in the EPS group. After the pullout tests, the block destructions were the most severe in the PMMA-PS group and the lightest in the CPS group. Hole diameters in the PMMA-PS and the EPS groups were significantly larger than that in the CPS group, whereas the diameter of the hole in the PMMA-PS group was significantly greater than that in the EPS group.<\/jats:p>\n <\/jats:sec>\n \n Conclusions:<\/jats:title>\n EPS can significantly increase the strength of screw fixation compared with CPS in osteoporotic synthetic bone. Although EPS shows a weaker fixation strength compared with PMMA-PS in the osteoporotic synthetic bone, it may still provide an alternative option to prevent screw loosening in the clinical treatment of osteoporosis.<\/jats:p>\n <\/jats:sec>","DOI":"10.1097\/bsd.0b013e31828bfc85","type":"journal-article","created":{"date-parts":[[2013,4,4]],"date-time":"2013-04-04T09:58:02Z","timestamp":1365069482000},"page":"E351-E357","source":"Crossref","is-referenced-by-count":31,"title":["Biomechanical Comparison of Expansive Pedicle Screw and Polymethylmethacrylate-augmented Pedicle Screw in Osteoporotic Synthetic Bone in Primary Implantation"],"prefix":"10.1097","volume":"29","author":[{"given":"Da","family":"Liu","sequence":"first","affiliation":[{"name":"Department of Orthopaedics, General Hospital of Chengdu Military Region, Chengdu, Sichuan Province"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Shi","sequence":"additional","affiliation":[{"name":"Orthopaedics"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei","family":"Lei","sequence":"additional","affiliation":[{"name":"Orthopaedics"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meng-Qi","family":"Wei","sequence":"additional","affiliation":[{"name":"Radiology, Xijing Hospital, Fourth Military Medical University, Xi\u2019an, Shaanxi Province, P.R. China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bo","family":"Qu","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics, General Hospital of Chengdu Military Region, Chengdu, Sichuan Province"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shao-Lin","family":"Deng","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics, General Hospital of Chengdu Military Region, Chengdu, Sichuan Province"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xian-Ming","family":"Pan","sequence":"additional","affiliation":[{"name":"Department of Orthopaedics, General Hospital of Chengdu Military Region, Chengdu, Sichuan Province"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"276","reference":[{"key":"R1-20230831","first-page":"1096","article-title":"Outcomes of posterior fusion using pedicle screw fixation in patients> or =70 years with lumbar spinal canal stenosis","volume":"31","author":"Tokuhashi","year":"2008","journal-title":"Orthopedics"},{"key":"R2-20230831","doi-asserted-by":"crossref","first-page":"207","DOI":"10.3171\/2008.12.SPINE0844","article-title":"Clinical and radiographic outcomes of pedicle screw fixation for upper thoracic spine (T1-5) fractures: a retrospective cohort study of 27 cases","volume":"10","author":"Fisher","year":"2009","journal-title":"J Neurosurg Spine"},{"key":"R3-20230831","doi-asserted-by":"crossref","first-page":"1533","DOI":"10.1097\/BRS.0b013e318067dc3d","article-title":"Comparison of segmental pedicle screw instrumentation versus anterior instrumentation in adolescent idiopathic thoracolumbar and lumbar scoliosis","volume":"32","author":"Hee","year":"2007","journal-title":"Spine (Phila Pa 1976)"},{"key":"R4-20230831","doi-asserted-by":"crossref","first-page":"531","DOI":"10.1227\/01.NEU.0000290899.15567.68","article-title":"Segmental polymethylmethacrylate-augmented pedicle screw fixation in patients with bone softening caused by osteoporosis and metastatic tumor involvement: a clinical evaluation","volume":"61","author":"Frankel","year":"2007","journal-title":"Neurosurgery"},{"key":"R5-20230831","doi-asserted-by":"crossref","first-page":"2415","DOI":"10.1097\/00007632-199411000-00008","article-title":"Effects of bone mineral density on pedicle screw fixation","volume":"19","author":"Halverson","year":"1994","journal-title":"Spine (Phila Pa 1976)"},{"key":"R6-20230831","doi-asserted-by":"crossref","first-page":"1454","DOI":"10.1097\/00007632-199707010-00006","article-title":"The effect of bone quality on pedicle screw loading in axial instability. 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