{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,11,10]],"date-time":"2026-11-10T15:23:03Z","timestamp":1794324183024,"version":"4.9.0"},"reference-count":48,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["FOC"],"published-print":{"date-parts":[[2010,6]]},"abstract":"\n Object<\/jats:title>\n Dynamic stabilization systems are used to stabilize degenerative lumbar spondylosis. Loosening of the pedicle screws in such nonfusion implants is predictable. This retrospective study evaluated the incidence of screw loosening and its effect on clinical outcomes.<\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n Charts, radiographic films, and medical records of 71 consecutive patients who underwent decompression using Dynesys dynamic stabilization for 1- or 2-level lumbar spondylosis were reviewed. Radiographic films were evaluated and compared to detect screw loosening. A visual analog scale (VAS) for back pain and the Oswestry Disability Index (ODI) were used for measuring clinical outcome. Statistical analysis was conducted using the chisquare test and Student t-test.<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n The 71 patients in the study sample had a mean age of 59.2 \u00b1 11.65 years (range 23\u201380 years), with slight female predominance (39 women, 32 men). The mean follow-up duration was 16.6 months (range 8\u201329 months). There were loose screws in 14 of 71 patients (19.7%), for a rate of 4.6% per screw (17 of 368 screws). Most screw loosening occurred in patients \u2265 55 years old (13 of 14 patients) although age and sex had no effect on screw loosening (p = 0.233 and 0.109, respectively). Both the loose screw and solid screw groups experienced significant improvement after the surgery in VAS and ODI scores. On the VAS, scores improved from 5.9 \u00b1 2.99 to 2.1 \u00b1 2.14 in the loose screw group (p = 0.003), and from 5.7 \u00b1 3.45 to 2.9 \u00b1 2.68 in the solid screw group (p < 0.001). For the ODI scale, scores improved from 43.5 \u00b1 16.78% to 28.0 \u00b1 18.18% (p = 0.006) in the loose screw group, and from 52.1 \u00b1 20.92% to 24.6 \u00b1 19.78% (p < 0.001) in the solid screw group. There were no significant differences between the 2 groups (p = 0.334 for VAS, p = 0.567 for ODI).<\/jats:p>\n <\/jats:sec>\n \n Conclusions<\/jats:title>\n The preliminary study of this pedicle-based dynamic stabilization device for 1- and 2-level lumbar spondylosis shows radiographic evidence of screw loosening in 19.7% of patients and 4.6% of screws. Nonetheless, the loosening of screws has no adverse effect on clinical improvement.<\/jats:p>\n <\/jats:sec>","DOI":"10.3171\/2010.3.focus1052","type":"journal-article","created":{"date-parts":[[2011,2,23]],"date-time":"2011-02-23T11:43:05Z","timestamp":1298461385000},"page":"E10","source":"Crossref","is-referenced-by-count":103,"title":["Screw loosening in the Dynesys stabilization system: radiographic evidence and effect on outcomes"],"prefix":"10.3171","volume":"28","author":[{"given":"Chin-Chu","family":"Ko","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Neurological Institute, and"},{"name":"School of Medicine, National Yang-Ming University;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hsiao-Wen","family":"Tsai","sequence":"additional","affiliation":[{"name":"Departments of Obstetrics and Gynecology and"},{"name":"School of Medicine, National Yang-Ming University;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wen-Cheng","family":"Huang","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Neurological Institute, and"},{"name":"School of Medicine, National Yang-Ming University;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jau-Ching","family":"Wu","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Neurological Institute, and"},{"name":"School of Medicine, National Yang-Ming University;"},{"name":"Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan; and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu-Chun","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Medicine, National Yang-Ming University;"},{"name":"Department of Medical Informatics, Heidelberg University, Heidelberg, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yang-Hsin","family":"Shih","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Neurological Institute, and"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hung-Chieh","family":"Chen","sequence":"additional","affiliation":[{"name":"Radiology, Taipei Veterans General Hospital;"},{"name":"School of Medicine, National Yang-Ming University;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ching-Lan","family":"Wu","sequence":"additional","affiliation":[{"name":"Radiology, Taipei Veterans General Hospital;"},{"name":"School of Medicine, National Yang-Ming University;"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Henrich","family":"Cheng","sequence":"additional","affiliation":[{"name":"Department of Neurosurgery, Neurological Institute, and"},{"name":"School of Medicine, National Yang-Ming University;"},{"name":"Institute of Pharmacology, National Yang-Ming University, Taipei, Taiwan; and"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"key":"b1-0280010","series-title":"J Spinal Disord","first-page":"464","article-title":"Postfusion instability at the adjacent segments after rigid pedicle screw fixation for degenerative lumbar spinal disorders","volume":"8","author":"Aota","year":"1995"},{"key":"b2-0280010","series-title":"Z Orthop Ihre Grenzgeb","first-page":"418","article-title":"[Posterior dynamic stabilization as an alternative for dorsoventral fusion in spinal stenosis with degenerative instability.]","volume":"141","author":"Cakir","year":"2003"},{"key":"b3-0280010","series-title":"Scand J Rheumatol","doi-asserted-by":"publisher","first-page":"210","DOI":"10.1080\/03009740410005458","article-title":"Stabilisation surgery for chronic low back pain: indications, surgical procedures, and outcome","volume":"33","author":"Christensen","year":"2004"},{"key":"b4-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"1486","DOI":"10.1007\/s00586-009-1071-0","article-title":"Inter-observer reliability of detecting Dynesys pedicle screw using plain X-rays: a study on 50 post-operative patients","volume":"18","author":"Dakhil-Jerew","year":"2009"},{"key":"b5-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"227","DOI":"10.1097\/BRS.0b013e3181bd3be6","article-title":"Dynamic stabilization for degenerative lumbar scoliosis in elderly patients","volume":"35","author":"Di Silvestre","year":"2010"},{"key":"b6-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"2940","DOI":"10.1097\/00007632-200011150-00017","article-title":"The Oswestry Disability Index","volume":"25","author":"Fairbank","year":"2000"},{"key":"b7-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"553","DOI":"10.1097\/00007632-199903150-00010","article-title":"A randomized prospective study of posterolateral lumbar fusion. Outcomes with and without pedicle screw instrumentation","volume":"24","author":"France","year":"1999"},{"key":"b8-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"178","DOI":"10.1007\/s00586-002-0493-8","article-title":"Complications in lumbar fusion surgery for chronic low back pain: comparison of three surgical techniques used in a prospective randomized study. A report from the Swedish Lumbar Spine Study Group","volume":"12","author":"Fritzell","year":"2003"},{"key":"b9-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"324","DOI":"10.1097\/01.brs.0000152584.46266.25","article-title":"Clinical experience with the Dynesys semirigid fixation system for the lumbar spine: surgical and patient-oriented outcome in 50 cases after an average of 2 years","volume":"30","author":"Grob","year":"2005"},{"issue":"165","key":"b10-0280010","series-title":"Clin Orthop Relat Res","first-page":"110","article-title":"Instability of the lumbar spine","author":"Kirkaldy-Willis","year":"1982"},{"key":"b11-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"815","DOI":"10.1007\/s00586-009-0941-9","article-title":"Treatment of degenerative spondylolisthesis: potential impact of dynamic stabilization based on imaging analysis","volume":"18","author":"Lawhorne","year":"2009"},{"key":"b12-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"2774","DOI":"10.1097\/00007632-199412150-00007","article-title":"Complications after transpedicular stabilization of the spine. A survivorship analysis of 163 cases","volume":"19","author":"Ohlin","year":"1994"},{"key":"b13-0280010","series-title":"J Bone Joint Surg Br","doi-asserted-by":"publisher","first-page":"183","DOI":"10.1302\/0301-620X.79B2.0790183","article-title":"Complications of transpedicular lumbosacral fixation for non-traumatic disorders","volume":"79","author":"Pihlaj\u00e4maki","year":"1997"},{"key":"b14-0280010","series-title":"Z Orthop Ihre Grenzgeb","first-page":"166","article-title":"[Application of a dynamic pedicle screw system (DYNESYS) for lumbar segmental degenerations - comparison of clinical and radiological results for different indications.]","volume":"142","author":"Putzier","year":"2004"},{"key":"b15-0280010","series-title":"J Spinal Disord","first-page":"392","article-title":"Adjacent-segment degeneration after lumbar fusion with instrumentation: a retrospective study","volume":"9","author":"Rahm","year":"1996"},{"key":"b16-0280010","series-title":"J Bone Joint Surg Br","first-page":"457","article-title":"The significance of radiolucent zones surrounding pedicle screws. Definition of screw loosening in spinal instrumentation","volume":"86","author":"Sand\u00e9n","year":"2004"},{"key":"b17-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"E636","DOI":"10.1097\/BRS.0b013e31817d2435","article-title":"Minimum four-year follow-up of spinal stenosis with degenerative spondylolisthesis treated with decompression and dynamic stabilization","volume":"33","author":"Schaeren","year":"2008"},{"key":"b18-0280010","series-title":"J Spinal Disord Tech","doi-asserted-by":"publisher","first-page":"418","DOI":"10.1097\/00024720-200308000-00015","article-title":"Dynamic stabilization of the lumbar spine and its effects on adjacent segments: an in vitro experiment","volume":"16","author":"Schmoelz","year":"2003"},{"key":"b19-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"442","DOI":"10.1097\/01.brs.0000200092.49001.6e","article-title":"Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis","volume":"31","author":"Schnake","year":"2006"},{"key":"b20-0280010","series-title":"Orthop Clin North Am","doi-asserted-by":"publisher","first-page":"363","DOI":"10.1016\/j.ocl.2005.03.001","article-title":"Posterior dynamic stabilization systems: DYNESYS","volume":"36","author":"Schwarzenbach","year":"2005"},{"issue":"Suppl 2","key":"b21-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"S170","DOI":"10.1007\/s00586-002-0438-2","article-title":"The dynamic neutralization system for the spine: a multi-center study of a novel nonfusion system","volume":"11","author":"Stoll","year":"2002"},{"key":"b22-0280010","series-title":"JAMA","doi-asserted-by":"publisher","first-page":"907","DOI":"10.1001\/jama.1992.03490070089049","article-title":"Patient outcomes after lumbar spinal fusions","volume":"268","author":"Turner","year":"1992"},{"key":"b23-0280010","series-title":"Osteoporos Int","doi-asserted-by":"publisher","first-page":"1651","DOI":"10.1007\/s00198-009-0925-y","article-title":"Osteoporosis in China","volume":"20","author":"Wang","year":"2009"},{"key":"b24-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"696","DOI":"10.1097\/00007632-198813060-00019","article-title":"New uses and refinements of the paraspinal approach to the lumbar spine","volume":"13","author":"Wiltse","year":"1988"},{"key":"b1-0280010","series-title":"J Spinal Disord","first-page":"464","article-title":"Postfusion instability at the adjacent segments after rigid pedicle screw fixation for degenerative lumbar spinal disorders","volume":"8","author":"Aota","year":"1995"},{"key":"b2-0280010","series-title":"Z Orthop Ihre Grenzgeb","first-page":"418","article-title":"[Posterior dynamic stabilization as an alternative for dorsoventral fusion in spinal stenosis with degenerative instability.]","volume":"141","author":"Cakir","year":"2003"},{"key":"b3-0280010","series-title":"Scand J Rheumatol","doi-asserted-by":"publisher","first-page":"210","DOI":"10.1080\/03009740410005458","article-title":"Stabilisation surgery for chronic low back pain: indications, surgical procedures, and outcome","volume":"33","author":"Christensen","year":"2004"},{"key":"b4-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"1486","DOI":"10.1007\/s00586-009-1071-0","article-title":"Inter-observer reliability of detecting Dynesys pedicle screw using plain X-rays: a study on 50 post-operative patients","volume":"18","author":"Dakhil-Jerew","year":"2009"},{"key":"b5-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"227","DOI":"10.1097\/BRS.0b013e3181bd3be6","article-title":"Dynamic stabilization for degenerative lumbar scoliosis in elderly patients","volume":"35","author":"Di Silvestre","year":"2010"},{"key":"b6-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"2940","DOI":"10.1097\/00007632-200011150-00017","article-title":"The Oswestry Disability Index","volume":"25","author":"Fairbank","year":"2000"},{"key":"b7-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"553","DOI":"10.1097\/00007632-199903150-00010","article-title":"A randomized prospective study of posterolateral lumbar fusion. Outcomes with and without pedicle screw instrumentation","volume":"24","author":"France","year":"1999"},{"key":"b8-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"178","DOI":"10.1007\/s00586-002-0493-8","article-title":"Complications in lumbar fusion surgery for chronic low back pain: comparison of three surgical techniques used in a prospective randomized study. A report from the Swedish Lumbar Spine Study Group","volume":"12","author":"Fritzell","year":"2003"},{"key":"b9-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"324","DOI":"10.1097\/01.brs.0000152584.46266.25","article-title":"Clinical experience with the Dynesys semirigid fixation system for the lumbar spine: surgical and patient-oriented outcome in 50 cases after an average of 2 years","volume":"30","author":"Grob","year":"2005"},{"issue":"165","key":"b10-0280010","series-title":"Clin Orthop Relat Res","first-page":"110","article-title":"Instability of the lumbar spine","author":"Kirkaldy-Willis","year":"1982"},{"key":"b11-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"815","DOI":"10.1007\/s00586-009-0941-9","article-title":"Treatment of degenerative spondylolisthesis: potential impact of dynamic stabilization based on imaging analysis","volume":"18","author":"Lawhorne","year":"2009"},{"key":"b12-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"2774","DOI":"10.1097\/00007632-199412150-00007","article-title":"Complications after transpedicular stabilization of the spine. A survivorship analysis of 163 cases","volume":"19","author":"Ohlin","year":"1994"},{"key":"b13-0280010","series-title":"J Bone Joint Surg Br","doi-asserted-by":"publisher","first-page":"183","DOI":"10.1302\/0301-620X.79B2.0790183","article-title":"Complications of transpedicular lumbosacral fixation for non-traumatic disorders","volume":"79","author":"Pihlaj\u00e4maki","year":"1997"},{"key":"b14-0280010","series-title":"Z Orthop Ihre Grenzgeb","first-page":"166","article-title":"[Application of a dynamic pedicle screw system (DYNESYS) for lumbar segmental degenerations - comparison of clinical and radiological results for different indications.]","volume":"142","author":"Putzier","year":"2004"},{"key":"b15-0280010","series-title":"J Spinal Disord","first-page":"392","article-title":"Adjacent-segment degeneration after lumbar fusion with instrumentation: a retrospective study","volume":"9","author":"Rahm","year":"1996"},{"key":"b16-0280010","series-title":"J Bone Joint Surg Br","first-page":"457","article-title":"The significance of radiolucent zones surrounding pedicle screws. Definition of screw loosening in spinal instrumentation","volume":"86","author":"Sand\u00e9n","year":"2004"},{"key":"b17-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"E636","DOI":"10.1097\/BRS.0b013e31817d2435","article-title":"Minimum four-year follow-up of spinal stenosis with degenerative spondylolisthesis treated with decompression and dynamic stabilization","volume":"33","author":"Schaeren","year":"2008"},{"key":"b18-0280010","series-title":"J Spinal Disord Tech","doi-asserted-by":"publisher","first-page":"418","DOI":"10.1097\/00024720-200308000-00015","article-title":"Dynamic stabilization of the lumbar spine and its effects on adjacent segments: an in vitro experiment","volume":"16","author":"Schmoelz","year":"2003"},{"key":"b19-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"442","DOI":"10.1097\/01.brs.0000200092.49001.6e","article-title":"Dynamic stabilization in addition to decompression for lumbar spinal stenosis with degenerative spondylolisthesis","volume":"31","author":"Schnake","year":"2006"},{"key":"b20-0280010","series-title":"Orthop Clin North Am","doi-asserted-by":"publisher","first-page":"363","DOI":"10.1016\/j.ocl.2005.03.001","article-title":"Posterior dynamic stabilization systems: DYNESYS","volume":"36","author":"Schwarzenbach","year":"2005"},{"issue":"Suppl 2","key":"b21-0280010","series-title":"Eur Spine J","doi-asserted-by":"publisher","first-page":"S170","DOI":"10.1007\/s00586-002-0438-2","article-title":"The dynamic neutralization system for the spine: a multi-center study of a novel nonfusion system","volume":"11","author":"Stoll","year":"2002"},{"key":"b22-0280010","series-title":"JAMA","doi-asserted-by":"publisher","first-page":"907","DOI":"10.1001\/jama.1992.03490070089049","article-title":"Patient outcomes after lumbar spinal fusions","volume":"268","author":"Turner","year":"1992"},{"key":"b23-0280010","series-title":"Osteoporos Int","doi-asserted-by":"publisher","first-page":"1651","DOI":"10.1007\/s00198-009-0925-y","article-title":"Osteoporosis in China","volume":"20","author":"Wang","year":"2009"},{"key":"b24-0280010","series-title":"Spine","doi-asserted-by":"publisher","first-page":"696","DOI":"10.1097\/00007632-198813060-00019","article-title":"New uses and refinements of the paraspinal approach to the lumbar spine","volume":"13","author":"Wiltse","year":"1988"}],"container-title":["Neurosurgical Focus"],"original-title":[],"link":[{"URL":"https:\/\/thejns.org\/view\/journals\/neurosurg-focus\/28\/6\/2010.3.focus1052.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/neurosurg-focus\/28\/6\/2010.3.focus1052.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/thejns.org\/downloadpdf\/journals\/neurosurg-focus\/28\/6\/2010.3.focus1052.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,6,6]],"date-time":"2026-06-06T08:16:23Z","timestamp":1780733783000},"score":1,"resource":{"primary":{"URL":"https:\/\/thejns.org\/view\/journals\/neurosurg-focus\/28\/6\/2010.3.focus1052.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2010,6]]},"references-count":48,"journal-issue":{"issue":"6"},"URL":"https:\/\/doi.org\/10.3171\/2010.3.focus1052","relation":{},"ISSN":["1092-0684"],"issn-type":[{"value":"1092-0684","type":"electronic"}],"subject":[],"published":{"date-parts":[[2010,6]]}}}