{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,15]],"date-time":"2026-06-15T05:41:25Z","timestamp":1781502085701,"version":"3.54.1"},"reference-count":114,"publisher":"Journal of Neurosurgery Publishing Group (JNSPG)","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["FOC"],"published-print":{"date-parts":[[2015,4]]},"abstract":"\n OBJECT<\/jats:title>\n Chiari I malformation is the most common craniocervical malformation. Its combination with basilar invagination in a significant proportion of patients is well established. This study presents surgical results for patients with Chiari I malformation with and without additional basilar invagination.<\/jats:p>\n <\/jats:sec>\n \n METHOD<\/jats:title>\n Three hundred twenty-three patients underwent 350 operations between 1985 and 2013 (mean age 43 \u00b1 16 years, mean history of symptoms 64 \u00b1 94 months). The clinical courses were documented with a score system for individual neurological symptoms for short-term results after 3 and 12 months. Long-term outcomes were analyzed with Kaplan-Meier statistics. The mean follow-up was 53 \u00b1 58 months (the means are expressed \u00b1 SD).<\/jats:p>\n <\/jats:sec>\n \n RESULTS<\/jats:title>\n Patients with (n = 46) or without (n = 277) basilar invagination in addition to Chiari I malformation were identified. Patients with invagination were separated into groups: those with (n = 31) and without (n = 15) ventral compression by the odontoid in the foramen magnum. Of the 350 operations, 313 dealt with the craniospinal pathology, 28 surgeries were undertaken for degenerative diseases of the cervical spine, 3 were performed for hydrocephalus, and 6 syrinx catheters were removed for cord tethering. All craniospinal operations included a foramen magnum decompression with arachnoid dissection, opening of the fourth ventricle, and a duraplasty. In patients without invagination, craniospinal instability was detected in 4 individuals, who required additional craniospinal fusion. In patients with invagination but without ventral compression, no stabilization was added to the decompression. In all patients with ventral compression, craniospinal stabilization was performed with the foramen magnum decompression, except for 4 patients with mild ventral compression early in the series who underwent posterior decompression only. Among those with ventral compression, 9 patients with caudal cranial nerve dysfunctions underwent a combination of transoral decompression with posterior decompression and fusion.<\/jats:p>\n Within the 1st postoperative year, neurological scores improved for all symptoms in each patient group, with the most profound improvement for occipital pain. In the long term, late postoperative deteriorations were related to reobstruction of CSF flow in patients without invagination (18.3% in 10 years), whereas deteriorations in patients with invagination (24.9% in 10 years) were exclusively related either to instabilities becoming manifest after a foramen magnum decompression or to hardware failures. Results for ventral and posterior fusions for degenerative disc diseases in these patients indicated a trend for better long-term results with posterior operations.<\/jats:p>\n <\/jats:sec>\n \n CONCLUSIONS<\/jats:title>\n The great majority of patients with Chiari I malformations with or without basilar invagination report postoperative improvements with this management algorithm. There were no significant differences in short-term or long-term outcomes between these groups. Chiari I malformations without invagination and those with invaginations but without ventral compression can be managed by foramen magnum decompression alone. The majority of patients with ventral compression can be treated by posterior decompression, realignment, and stabilization, reserving anterior decompressions for patients with profound, symptomatic brainstem compression.<\/jats:p>\n <\/jats:sec>","DOI":"10.3171\/2015.1.focus14783","type":"journal-article","created":{"date-parts":[[2015,4,1]],"date-time":"2015-04-01T13:05:25Z","timestamp":1427893525000},"page":"E12","source":"Crossref","is-referenced-by-count":75,"title":["Chiari I malformation with and without basilar invagination: a comparative study"],"prefix":"10.3171","volume":"38","author":[{"given":"J\u00f6rg","family":"Klekamp","sequence":"first","affiliation":[{"name":"Department of Neurosurgery, Christliches Krankenhaus, Quakenbr\u00fcck, Germany"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1754","reference":[{"key":"b1-focus14783","series-title":"Neurosurgery","first-page":"308","article-title":"Long-term follow-up of Chiari-related syringomyelia in adults: analysis of 157 surgically treated cases","volume":"64","author":"Aghakhani","year":"2009"},{"issue":"Suppl 1","key":"b2-focus14783","series-title":"Neurochirurgie","first-page":"23","article-title":"Syringomyelia and Chiari abnormality in the adult. Analysis of the results of a cooperative series of 285 cases.]","volume":"45","author":"Aghakhani","year":"1999"},{"key":"b3-focus14783","series-title":"J Emerg Med","first-page":"569","article-title":"A craniocervical malformation presenting as acute respiratory failure","volume":"14","author":"Ali","year":"1996"},{"key":"b4-focus14783","series-title":"Neurol India","first-page":"470","article-title":"Factors influencing the outcome in symptomatic Chiari I malformation","volume":"52","author":"Arora","year":"2004"},{"key":"b5-focus14783","series-title":"J Spinal Disord Tech","first-page":"170","article-title":"Assuring optimal physiologic craniocervical alignment and avoidance of swallowing-related complications after occipitocervical fusion by preoperative halo vest placement","volume":"22","author":"Bagley","year":"2009"},{"key":"b6-focus14783","series-title":"J Neurosurg","first-page":"232","article-title":"Surgical treatment of Chiari malformation with and without syringomyelia experience with 177 adult patients","volume":"118","author":"Batzdorf","year":"2013"},{"key":"b7-focus14783","series-title":"J Neurosurg Pediatr","first-page":"134","article-title":"Complex Chiari malformations in children: an analysis of preoperative risk factors for occipitocervical fusion","volume":"10","author":"Bollo","year":"2012"},{"key":"b8-focus14783","series-title":"J Neurosurg Spine","first-page":"444","article-title":"Basilar invagination: craniocervical instability treated with cervical traction and occipitocervical fixation. Case report","volume":"7","author":"Botelho","year":"2007"},{"issue":"3 Suppl","key":"b9-focus14783","series-title":"J Neurosurg","first-page":"187","article-title":"The role of limited posterior fossa craniectomy in the surgical treatment of Chiari malformation Type I: experience with a pediatric series","volume":"106","author":"Caldarelli","year":"2007"},{"key":"b10-focus14783","series-title":"Yale J Biol Med","first-page":"487","article-title":"Basilar impression (platybasia): a bizarre developmental anomaly of the occipital bone and upper cervical spine with striking and misleading neurologic manifestations","volume":"11","author":"Chamberlain","year":"1939"},{"key":"b11-focus14783","series-title":"J Neurosurg Pediatr","first-page":"119","article-title":"Application of neuromuscular blockade and intraoperative 3D imaging in the reduction of basilar invagination","volume":"9","author":"Dahdaleh","year":"2012"},{"key":"b12-focus14783","series-title":"World Neurosurg","first-page":"357","article-title":"Biomechanical stability of a posterior-alone fixation technique after craniovertebral junction realignment","volume":"77","author":"Daniel","year":"2012"},{"key":"b13-focus14783","series-title":"J Clin Neurosci","first-page":"1726","article-title":"Resolution of cervical syringomyelia after transoral odontoidectomy and occipitocervical fusion in a patient with basilar invagination and Type I Chiari malformation","volume":"19","author":"Dickman","year":"2012"},{"key":"b14-focus14783","series-title":"Clin Neurol Neurosurg","first-page":"58","article-title":"The case for duraplasty in adults undergoing posterior fossa decompression for Chiari I malformation: a systematic review and meta-analysis of observational studies","volume":"125","author":"F\u00f6rander","year":"2014"},{"issue":"Suppl 1","key":"b15-focus14783","series-title":"Eur Spine J","first-page":"S55","article-title":"Endoscopic transnasal odontoid resection to decompress the bulbomedullary junction: a reliable anterior minimally invasive technique without posterior fusion","volume":"21","author":"Gladi","year":"2012"},{"key":"b16-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"E551","article-title":"Progressive basilar invagination after transoral odontoidectomy: treatment by atlantoaxial facet distraction and craniovertebral realignment","volume":"30","author":"Goel","year":"2005"},{"key":"b17-focus14783","series-title":"J Neurosurg Spine","first-page":"281","article-title":"Treatment of basilar invagination by atlantoaxial joint distraction and direct lateral mass fixation","volume":"1","author":"Goel","year":"2004"},{"key":"b18-focus14783","series-title":"J Neurosurg","first-page":"962","article-title":"Basilar invagination: a study based on 190 surgically treated patients","volume":"88","author":"Goel","year":"1998"},{"key":"b19-focus14783","series-title":"Neurol India","first-page":"144","article-title":"Atlantoaxial joint distraction as a treatment for basilar invagination: a report of an experience with 11 cases","volume":"56","author":"Goel","year":"2008"},{"key":"b20-focus14783","series-title":"J Neurosurg Spine","first-page":"220","article-title":"Reversal of longstanding musculoskeletal changes in basilar invagination after surgical decompression and stabilization","volume":"10","author":"Goel","year":"2009"},{"key":"b21-focus14783","series-title":"Pediatr Neurosurg","first-page":"375","article-title":"Surgical management of Chiari malformation: analysis of 128 cases","volume":"43","author":"Guo","year":"2007"},{"key":"b22-focus14783","series-title":"Eur Spine J","first-page":"1211","article-title":"C1-C2 arthrodesis after transoral odontoidectomy and suboccipital craniectomy for ventral brain stem compression in Chiari I patients","volume":"17","author":"Hwang","year":"2008"},{"key":"b23-focus14783","series-title":"Neurosurgery","first-page":"678","article-title":"Direct posterior reduction and fixation for the treatment of basilar invagination with atlantoaxial dislocation","volume":"66","author":"Jian","year":"2010"},{"issue":"3 Suppl","key":"b24-focus14783","series-title":"J Neurosurg","first-page":"298","article-title":"Resolution of syringomyelia and basilar invagination after traction. Case illustration","volume":"98","author":"Joseph","year":"2003"},{"issue":"2","key":"b25-focus14783","series-title":"Neurosurg Focus","first-page":"E4","article-title":"Intraoperative magnetic resonance imaging-augmented transoral resection of axial disease","volume":"10","author":"Kaibara","year":"2001"},{"key":"b26-focus14783","series-title":"J Am Stat Assoc","first-page":"457","article-title":"Nonparametric estimation from incomplete observations","volume":"53","author":"Kaplan","year":"1958"},{"issue":"2 Suppl","key":"b27-focus14783","series-title":"J Neurosurg","first-page":"189","article-title":"Treatment of basilar invagination associated with Chiari I malformations in the pediatric population: cervical reduction and posterior occipitocervical fusion","volume":"101","author":"Kim","year":"2004"},{"key":"b28-focus14783","series-title":"J Neurosurg Pediatr","first-page":"538","article-title":"Neurological deterioration after foramen magnum decompression for Chiari malformation type I: old or new pathology?","volume":"10","author":"Klekamp","year":"2012"},{"key":"b29-focus14783","series-title":"Neurosurgery","first-page":"365","article-title":"Surgical treatment of Chiari I malformation-analysis of intraoperative findings, complications, and outcome for 371 foramen magnum decompressions","volume":"71","author":"Klekamp","year":"2012"},{"key":"b30-focus14783","series-title":"Acta Neurochir (Wien)","first-page":"788","article-title":"The surgical treatment of Chiari I malformation","volume":"138","author":"Klekamp","year":"1996"},{"key":"b31-focus14783","series-title":"Acta Neurochir (Wien)","first-page":"221","article-title":"Introduction of a score system for the clinical evaluation of patients with spinal processes","volume":"123","author":"Klekamp","year":"1993"},{"key":"b32-focus14783","series-title":"Syringomyelia: Diagnosis and Treatment","author":"Klekamp","year":"2002"},{"key":"b33-focus14783","series-title":"Clin Neurol Neurosurg","first-page":"53","article-title":"High long-term symptomatic recurrence rates after Chiari-1 decompression without dural opening: a single center experience","volume":"118","author":"Krishna","year":"2014"},{"key":"b34-focus14783","series-title":"Br J Neurosurg","first-page":"409","article-title":"Chiari I malformation: surgical experience over a decade of management","volume":"22","author":"Kumar","year":"2008"},{"key":"b35-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"161","article-title":"Significance of occipitoaxial angle in subaxial lesion after occipitocervical fusion","volume":"26","author":"Matsunaga","year":"2001"},{"key":"b36-focus14783","series-title":"J Neurosurg Pediatr","first-page":"52","article-title":"Intraoperative ultrasonography as a guide to patient selection for duraplasty after suboccipital decompression in children with Chiari malformation Type I","volume":"2","author":"McGirt","year":"2008"},{"key":"b37-focus14783","series-title":"J Neurosurg","first-page":"301","article-title":"Craniovertebral junction abnormalities with hindbrain herniation and syringomyelia: regression of syringomyelia after removal of ventral craniovertebral junction compression","volume":"116","author":"Menezes","year":"2012"},{"key":"b38-focus14783","series-title":"Childs Nerv Syst","first-page":"1187","article-title":"Surgical approaches: postoperative care and complications \u201ctransoral-transpalatopharyngeal approach to the craniocervical junction.\u201d","volume":"24","author":"Menezes","year":"2008"},{"key":"b39-focus14783","series-title":"J Neurosurg","first-page":"444","article-title":"Craniocervical abnormalities. A comprehensive surgical approach","volume":"53","author":"Menezes","year":"1980"},{"key":"b40-focus14783","series-title":"Neurosurgery","first-page":"1005","article-title":"Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients","volume":"44","author":"Milhorat","year":"1999"},{"key":"b41-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"184","article-title":"O-C2 angle as a predictor of dyspnea and\/or dysphagia after occipitocervical fusion","volume":"34","author":"Miyata","year":"2009"},{"issue":"Suppl 1","key":"b42-focus14783","series-title":"Eur Spine J","first-page":"13","article-title":"Craniovertebral junction lesions: our experience with the transoral surgical approach","volume":"18","author":"Mouchaty","year":"2009"},{"key":"b43-focus14783","series-title":"J Neurosurg Pediatr","first-page":"474","article-title":"Decompression of Chiari malformation with and without duraplasty: morbidity versus recurrence","volume":"5","author":"Mutchnick","year":"2010"},{"issue":"2 Suppl","key":"b44-focus14783","series-title":"J Neurosurg","first-page":"246","article-title":"Further cranial settling of the upper cervical spine following odontoidectomy. Report of two cases","volume":"95","author":"Naderi","year":"2001"},{"key":"b45-focus14783","series-title":"Childs Nerv Syst","first-page":"349","article-title":"Surgical results of posterior fossa decompression for patients with Chiari I malformation","volume":"20","author":"Navarro","year":"2004"},{"key":"b46-focus14783","series-title":"J Neurosurg Spine","first-page":"117","article-title":"Occipitocervical fusion with rigid internal fixation: long-term follow-up data in 69 patients","volume":"7","author":"Nockels","year":"2007"},{"key":"b47-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"1528","article-title":"Treatment of primary basilar invagination by cervical traction and posterior instrumented reduction together with occipitocervical fusion","volume":"36","author":"Peng","year":"2011"},{"key":"b48-focus14783","series-title":"Z Orthop Ihre Grenzgeb","first-page":"364","article-title":"Dorsal occipitocervical fusion\u2014indications and results","volume":"136","author":"Pl\u00f6tz","year":"1998"},{"key":"b49-focus14783","series-title":"J Neurosurg Spine","first-page":"588","article-title":"Different surgical treatment techniques used by neurosurgeons and orthopedists for syringomyelia caused by Chiari I malformation in Japan","volume":"18","author":"Sakushima","year":"2013"},{"issue":"2 Suppl","key":"b50-focus14783","series-title":"J Neurosurg","first-page":"115","article-title":"Pediatric congenital atlantoaxial dislocation: differences between the irreducible and reducible varieties","volume":"104","author":"Salunke","year":"2006"},{"key":"b51-focus14783","series-title":"Minim Invasive Neurosurg","first-page":"179","article-title":"Endoscopic endonasal resection of the odontoid process as a standalone decompressive procedure for basilar invagination in Chiari type I malformation","volume":"54","author":"Scholtes","year":"2011"},{"key":"b52-focus14783","series-title":"Surg Neurol","first-page":"311","article-title":"Halo traction in basilar invagination: technical case report","volume":"66","author":"Simsek","year":"2006"},{"key":"b53-focus14783","series-title":"J Orthop Sci","first-page":"55","article-title":"Tonsillar herniation and the cervical spine: a morphometric study of 172 patients","volume":"12","author":"Takeuchi","year":"2007"},{"key":"b54-focus14783","series-title":"The Craniovertebral Junction. Diagnosis, Pathology, Surgical Techniques","first-page":"54","article-title":"Radiological investigations","author":"Ursekar","year":"2011"},{"key":"b55-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"2013","article-title":"C1 lateral mass screw placement in occipitalization with atlantoaxial dislocation and basilar invagination: a report of 146 cases","volume":"39","author":"Yin","year":"2014"},{"key":"b56-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"E267","article-title":"Upper-airway obstruction after short posterior occipitocervical fusion in a flexed position","volume":"32","author":"Yoshida","year":"2007"},{"key":"b57-focus14783","series-title":"Spinal Cord","first-page":"358","article-title":"Chiari I malformation associated with syringomyelia: a retrospective study of 316 surgically treated patients","volume":"46","author":"Zhang","year":"2008"},{"key":"b1-focus14783","series-title":"Neurosurgery","first-page":"308","article-title":"Long-term follow-up of Chiari-related syringomyelia in adults: analysis of 157 surgically treated cases","volume":"64","author":"Aghakhani","year":"2009"},{"issue":"Suppl 1","key":"b2-focus14783","series-title":"Neurochirurgie","first-page":"23","article-title":"Syringomyelia and Chiari abnormality in the adult. Analysis of the results of a cooperative series of 285 cases.]","volume":"45","author":"Aghakhani","year":"1999"},{"key":"b3-focus14783","series-title":"J Emerg Med","first-page":"569","article-title":"A craniocervical malformation presenting as acute respiratory failure","volume":"14","author":"Ali","year":"1996"},{"key":"b4-focus14783","series-title":"Neurol India","first-page":"470","article-title":"Factors influencing the outcome in symptomatic Chiari I malformation","volume":"52","author":"Arora","year":"2004"},{"key":"b5-focus14783","series-title":"J Spinal Disord Tech","first-page":"170","article-title":"Assuring optimal physiologic craniocervical alignment and avoidance of swallowing-related complications after occipitocervical fusion by preoperative halo vest placement","volume":"22","author":"Bagley","year":"2009"},{"key":"b6-focus14783","series-title":"J Neurosurg","first-page":"232","article-title":"Surgical treatment of Chiari malformation with and without syringomyelia experience with 177 adult patients","volume":"118","author":"Batzdorf","year":"2013"},{"key":"b7-focus14783","series-title":"J Neurosurg Pediatr","first-page":"134","article-title":"Complex Chiari malformations in children: an analysis of preoperative risk factors for occipitocervical fusion","volume":"10","author":"Bollo","year":"2012"},{"key":"b8-focus14783","series-title":"J Neurosurg Spine","first-page":"444","article-title":"Basilar invagination: craniocervical instability treated with cervical traction and occipitocervical fixation. Case report","volume":"7","author":"Botelho","year":"2007"},{"issue":"3 Suppl","key":"b9-focus14783","series-title":"J Neurosurg","first-page":"187","article-title":"The role of limited posterior fossa craniectomy in the surgical treatment of Chiari malformation Type I: experience with a pediatric series","volume":"106","author":"Caldarelli","year":"2007"},{"key":"b10-focus14783","series-title":"Yale J Biol Med","first-page":"487","article-title":"Basilar impression (platybasia): a bizarre developmental anomaly of the occipital bone and upper cervical spine with striking and misleading neurologic manifestations","volume":"11","author":"Chamberlain","year":"1939"},{"key":"b11-focus14783","series-title":"J Neurosurg Pediatr","first-page":"119","article-title":"Application of neuromuscular blockade and intraoperative 3D imaging in the reduction of basilar invagination","volume":"9","author":"Dahdaleh","year":"2012"},{"key":"b12-focus14783","series-title":"World Neurosurg","first-page":"357","article-title":"Biomechanical stability of a posterior-alone fixation technique after craniovertebral junction realignment","volume":"77","author":"Daniel","year":"2012"},{"key":"b13-focus14783","series-title":"J Clin Neurosci","first-page":"1726","article-title":"Resolution of cervical syringomyelia after transoral odontoidectomy and occipitocervical fusion in a patient with basilar invagination and Type I Chiari malformation","volume":"19","author":"Dickman","year":"2012"},{"key":"b14-focus14783","series-title":"Clin Neurol Neurosurg","first-page":"58","article-title":"The case for duraplasty in adults undergoing posterior fossa decompression for Chiari I malformation: a systematic review and meta-analysis of observational studies","volume":"125","author":"F\u00f6rander","year":"2014"},{"issue":"Suppl 1","key":"b15-focus14783","series-title":"Eur Spine J","first-page":"S55","article-title":"Endoscopic transnasal odontoid resection to decompress the bulbomedullary junction: a reliable anterior minimally invasive technique without posterior fusion","volume":"21","author":"Gladi","year":"2012"},{"key":"b16-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"E551","article-title":"Progressive basilar invagination after transoral odontoidectomy: treatment by atlantoaxial facet distraction and craniovertebral realignment","volume":"30","author":"Goel","year":"2005"},{"key":"b17-focus14783","series-title":"J Neurosurg Spine","first-page":"281","article-title":"Treatment of basilar invagination by atlantoaxial joint distraction and direct lateral mass fixation","volume":"1","author":"Goel","year":"2004"},{"key":"b18-focus14783","series-title":"J Neurosurg","first-page":"962","article-title":"Basilar invagination: a study based on 190 surgically treated patients","volume":"88","author":"Goel","year":"1998"},{"key":"b19-focus14783","series-title":"Neurol India","first-page":"144","article-title":"Atlantoaxial joint distraction as a treatment for basilar invagination: a report of an experience with 11 cases","volume":"56","author":"Goel","year":"2008"},{"key":"b20-focus14783","series-title":"J Neurosurg Spine","first-page":"220","article-title":"Reversal of longstanding musculoskeletal changes in basilar invagination after surgical decompression and stabilization","volume":"10","author":"Goel","year":"2009"},{"key":"b21-focus14783","series-title":"Pediatr Neurosurg","first-page":"375","article-title":"Surgical management of Chiari malformation: analysis of 128 cases","volume":"43","author":"Guo","year":"2007"},{"key":"b22-focus14783","series-title":"Eur Spine J","first-page":"1211","article-title":"C1-C2 arthrodesis after transoral odontoidectomy and suboccipital craniectomy for ventral brain stem compression in Chiari I patients","volume":"17","author":"Hwang","year":"2008"},{"key":"b23-focus14783","series-title":"Neurosurgery","first-page":"678","article-title":"Direct posterior reduction and fixation for the treatment of basilar invagination with atlantoaxial dislocation","volume":"66","author":"Jian","year":"2010"},{"issue":"3 Suppl","key":"b24-focus14783","series-title":"J Neurosurg","first-page":"298","article-title":"Resolution of syringomyelia and basilar invagination after traction. 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A comprehensive surgical approach","volume":"53","author":"Menezes","year":"1980"},{"key":"b40-focus14783","series-title":"Neurosurgery","first-page":"1005","article-title":"Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients","volume":"44","author":"Milhorat","year":"1999"},{"key":"b41-focus14783","series-title":"Spine (Phila Pa 1976)","first-page":"184","article-title":"O-C2 angle as a predictor of dyspnea and\/or dysphagia after occipitocervical fusion","volume":"34","author":"Miyata","year":"2009"},{"issue":"Suppl 1","key":"b42-focus14783","series-title":"Eur Spine J","first-page":"13","article-title":"Craniovertebral junction lesions: our experience with the transoral surgical approach","volume":"18","author":"Mouchaty","year":"2009"},{"key":"b43-focus14783","series-title":"J Neurosurg Pediatr","first-page":"474","article-title":"Decompression of Chiari malformation with and without duraplasty: morbidity versus recurrence","volume":"5","author":"Mutchnick","year":"2010"},{"issue":"2 Suppl","key":"b44-focus14783","series-title":"J Neurosurg","first-page":"246","article-title":"Further cranial settling of the upper cervical spine following odontoidectomy. 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