{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,26]],"date-time":"2026-10-26T02:04:51Z","timestamp":1792980291666,"version":"4.5.0"},"reference-count":21,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"6","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["SPI"],"published-print":{"date-parts":[[2011,6]]},"abstract":"\nObject<\/jats:title>\nExtension teardrop fracture of the axis is an extremely rare cervical spinal injury. The classic clinical features, which have mainly been described by radiologists rather than spine surgeons, include its occurrence in elderly patients with osteoporosis, an association with minimal or no prevertebral soft-tissue swelling, and an absence of associated neurological deficit. However, recent case studies indicate notable exceptions to these clinical features, although few studies have investigated osteoporosis in these patients. The purpose of the present study was to clarify the clinical features of extension teardrop fracture of the axis.<\/jats:p><\/jats:sec>\n\nMethods<\/jats:title>\nThe authors retrospectively reviewed data obtained in 13 patients with regard to their injury etiology, neurological deficit, treatment and outcome (residual neck pain), and imaging findings (size and displacement of the fragment, C2\u20133 subluxation, disc injury, and osteoporosis of the axis).<\/jats:p><\/jats:sec>\n\nResults<\/jats:title>\nExtension teardrop fracture of the axis constituted 11.6% of upper cervical spinal injuries at the authors' institute. The mean age of the patients was 49.5 years and distinct osteoporosis was identified in only 1 patient. A C2\u20133 subluxation was observed in 2 patients, in whom the displacement of the fragment was significant, although its size did not appear to have an effect. Magnetic resonance imaging, undertaken in 7 patients within 48 hours of injury, showed no disc injuries. Instability of the cervical spine was absent in all patient at follow-up. Only one patient underwent surgery for the presenting symptoms of dysphagia. The other patients were treated conservatively. The authors examined 9 patients directly; these patients had bony fusion and did not complain of neck pain, except for a patient with traumatic spondylolisthesis.<\/jats:p><\/jats:sec>\n\nConclusions<\/jats:title>\nExtension teardrop fracture of the axis is generally caused by hyperextension of the cervical spine caused by a direct high-energy blow to the forehead or mandible. Based on the present case study, the authors believe that osteopenia and older age should not be considered risk factors. Most patients with an extension teardrop fracture of the axis can be treated conservatively, and surgical intervention may only be indicated for specific cases, such as those in which a patient presents with dysphagia or with other complicated fractures.<\/jats:p><\/jats:sec>","DOI":"10.3171\/2011.1.spine10687","type":"journal-article","created":{"date-parts":[[2011,3,11]],"date-time":"2011-03-11T17:13:46Z","timestamp":1299863626000},"page":"710-714","source":"Crossref","is-referenced-by-count":19,"title":["Clinical features of the extension teardrop fracture of the axis: review of 13 cases"],"prefix":"10.3171","volume":"14","author":[{"given":"Masahiko","family":"Watanabe","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daisuke","family":"Sakai","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yukihiro","family":"Yamamoto","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Masato","family":"Sato","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joji","family":"Mochida","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"key":"b1-spine10687","series-title":"Imaging of Orthopedic Trauma and Surgery","first-page":"151","article-title":"The spine","author":"Berquist","year":"1992"},{"key":"b2-spine10687","series-title":"Spine","doi-asserted-by":"publisher","first-page":"593","DOI":"10.1097\/01.brs.0000257345.21075.a7","article-title":"Measurement techniques for upper cervical spine injuries: Consensus statement of the spine trauma study group","volume":"32","author":"Bono","year":"2007"},{"key":"b3-spine10687","series-title":"Eur J Orthop Surg Traumatol","doi-asserted-by":"publisher","first-page":"229","DOI":"10.1007\/s00590-005-0236-8","article-title":"Functional outcome following teardrop fracture of the axis","volume":"15","author":"Boran","year":"2005"},{"key":"b4-spine10687","series-title":"Injuries of the Cervical Spine","author":"Braakman","year":"1971"},{"key":"b5-spine10687","series-title":"Inj Control Saf Promot","doi-asserted-by":"publisher","first-page":"155","DOI":"10.1076\/icsp.10.3.155.14558","article-title":"Neck injuries among the elderly in Sweden","volume":"10","author":"Brolin","year":"2003"},{"key":"b6-spine10687","series-title":"Skeletal Radiol","doi-asserted-by":"publisher","first-page":"335","DOI":"10.1007\/BF00361422","article-title":"Acute injuries of the axis vertebra","volume":"18","author":"Burke","year":"1989"},{"key":"b7-spine10687","series-title":"AJR Am J Roentgenol","doi-asserted-by":"publisher","first-page":"803","DOI":"10.2214\/ajr.146.4.803","article-title":"Hyperextension dislocation of the cervical spine","volume":"146","author":"Edeiken-Monroe","year":"1986"},{"key":"b8-spine10687","series-title":"I Paraplegia","first-page":"179","article-title":"The value of postural reduction in the initial management of closed injuries of the spine with paraplegia and tetraplegia","volume":"7","author":"Frankel","year":"1969"},{"key":"b9-spine10687","series-title":"The Radiology of Vertebral Trauma","author":"Gehweiler","year":"1980"},{"key":"b10-spine10687","series-title":"Radiology of Acute Cervical Spine Trauma","author":"Harris","year":"1987"},{"key":"b11-spine10687","series-title":"The Radiology of Acute Cervical Spine Trauma","author":"Harris","year":"1996"},{"key":"b12-spine10687","series-title":"J Bone Joint Surg Am","doi-asserted-by":"publisher","first-page":"1534","DOI":"10.2106\/00004623-197052080-00002","article-title":"Fractures, dislocations, and fracture-dislocations of the spine","volume":"52","author":"Holdsworth","year":"1970"},{"key":"b13-spine10687","series-title":"J Bone Joint Surg Am","first-page":"985","article-title":"Chronic neurological sequelae of acute trauma to the spine and spinal cord. 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