Reversal of longstanding musculoskeletal changes in basilar invagination after surgical decompression and stabilization

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The authors investigated the changes in the bone architecture and the characteristics of the neck and craniovertebral region in selected cases of basilar invagination. The reversal in these changes that occurred after decompression and fixation are analyzed. The implications of such an analysis in understanding the pathogenesis of a number of features that are characteristically associated with basilar invagination are evaluated.


One hundred and seventy selected patients with basilar invagination who underwent atlantoaxial joint distraction-fixation surgery at the authors' institution between 1999 and April 2008 were reviewed. The study was prospective after June 2006. A variety of parameters were used for radiological and physical assessments. The evaluation was done on the basis of pre- and postoperative imaging studies and clinical photographs. In the 41 prospective cases, additional direct physical measurements of the neck were performed.


Prior to surgery there were several physical changes such as reduced neck length, torticollis, exaggerated lordosis of the cervical spine, and reduced craniospinal angulation. Other findings included reduced discspace height, significant posterior cervical osteophyte formation, assimilation of atlas (72%), single-level (29%) or multiple-level (3%) cervical fusions, and an increase in the spinal subarachnoid space both above and below the level of maximum neural compression at the tip of the odontoid process. After surgical decompression of the region, there was remarkable recovery in craniovertebral alignments, and an increase in neck length (maximum up to 42 mm) was obvious on physical and radiological examination in 85% of patients. The disc-space height increased and there was a reversal of altered cervical lordosis, craniospinal angulation (maximum up to 36°), and torticollis.


It appears that a number of physical spinal changes characteristically associated with basilar invagination such as a short neck, exaggerated neck lordosis, torticollis, cervical spondylotic changes and fusions are potentially reversible after decompression and stabilization of the craniovertebral junction.

Abbreviation used in this paper: CVJ = craniovertebral junction.

Article Information

Address correspondence to: Atul Goel, M.Ch., Department of Neurosurgery, King Edward Memorial Hospital and Seth G.S. Medical College, Parel, Mumbai 400012, India. email:

© AANS, except where prohibited by US copyright law.



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    Line drawing showing the measurements of craniovertebral and cervical heights. Line A is drawn from the tuberculum sellae to the confluence of sinuses. The distance from the midpoint of this line to the midpoint of the base of the C-5 vertebra (line B) measures the craniovertebral height. The distance from the tip of the odontoid process to the midpoint of the base of the C-5 vertebral body (VB) (line C) measures the cervical height.

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    Line drawing showing the parameters for measurement of the modified omega angle to assess cervical lordosis. Line A is drawn along the hard palate. Line B is parallel to Line A and passes through the center of the C-3 VB base. Line C extends from the center of the C-3 base along the tip of the odontoid process. The angle between line B and line C is the modified omega angle.

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    Line drawing demonstrating measurement of the craniospinal angle. Line A is drawn along the clivus and line B along the posterior surface of the C2–3 VBs. The angle between these lines is the craniospinal angle.

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    Images obtained in an 11-year-old girl with basilar invagination. Preoperative T2-weighted (A) and T1-weighted (B) MR images, and CT scan (C) demonstrating basilar invagination, partial assimilation of the atlas, and C2–3 fusion. Lateral radiograph in flexion (D) and extension (E) showing hyperlordosis of the cervical spine. Postoperative CT scan (F) and radiographs in extension (G) and flexion (H). Note craniovertebral and cervical spinal realignment and increase in craniovertebral and neck height. Also note the recovery in posterior cervical lordosis and increase in neck length.

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    Images obtained in a 55-year-old woman with basilar invagination. A: Preoperative CT scan showing basilar invagination and assimilation of the atlas. B: Preoperative T2-weighted MR image demonstrating basilar invagination and Chiari malformation. C: Postoperative CT scan showing realignment of CVJ and cervical spine.

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    Images obtained in a 40-year-old man with basilar invagination. A: Preoperative CT scan demonstrating basilar invagination, C2–3 fusion, and assimilation of atlas. B: Magnetic resonance image through the C1–2 facet joint showing the joint at an angle. C: T1-weighted MR image showing basilar invagination, Chiari malformation Type I, and syringomyelia. D: T2-weighted MR image. E: Lateral cervical spine radiograph. F: Postoperative CT scan. Note the realignment of CVJ and the cervical spine. G: Computed tomography scan with sagittal cut traversing the atlantoaxial joint showing plate and screw interarticular fixation and metal spacer within the joint. The alteration in alignment of the facets of the atlas and axis when compared to the preoperative view (B) can be appreciated. H: Postoperative extension radiograph showing fixation.



Chamberlain WE: Basilar impression (platybasia). A bizarre developmental anomaly of the occipital bone and upper cervical spine with striking and misleading neurologic manifestations. Yale J Biol Med 11:4874961939


David KMThorogood PVStevens JMCrockard HA: The dysmorphic cervical spine in Klippel-Feil syndrome: interpretations from developmental biology. Neurosurg Focus 6:6E11999


Goel A: High cervical C3–4 ‘disc’ compression associated with basilar invagination. Neurol India 56:68702008


Goel A: Progressive basilar invagination after transoral odontoidectomy: treatment by facet distraction and craniovertebral realignment. Spine 30:E551E5552005


Goel A: Treatment of basilar invagination by atlantoaxial joint distraction and direct lateral mass fixation. J Neurosurg Spine 1:2812862004


Goel ABhatjiwale MDesai K: Basilar invagination: a study based on 190 surgically treated cases. J Neurosurg 88:9629681998


Goel ADesai KMuzumdar D: Atlantoaxial fixation using plate and screw method: A report of 160 treated patients. Neurosurgery 51:135113572002


Goel ALaheri VK: Plate and screw fixation for atlanto-axial dislocation. Acta Neurochir (Wien) 129:47531994


Goel AShah A: Atlantoaxial joint distraction as a treatment for basilar invagination: a report of an experience with 11 cases. Neurol India 56:1441502008


Goel ASharma P: Craniovertebral junction realignment for the treatment of basilar invagination with syringomyelia: preliminary report of 12 cases. Neurol Med Chir (Tokyo) 45:5125182005


Grawitz P: Beitrag zur Lehre von der basilaren Impression des Schadels. Arch Path Anat Physiol 80:4491880


Gunderson CHGreenspan RHGlaser GHLubs HA: The Klippel-Feil syndrome: genetic and clinical reevaluation of cervical fusion. Medicine 46:4915121967


Klaus E: Rontgendiagnostik der platybasic und basilar Impression. Fortschr Rontgenstr 86:4604691957


Klippel MFeil A: Un cas d'absence des vertebres cervicales. Avec cage thoracique remontant jusqu'a la base du crane (cage thoracique cervicale). Nouv Iconog Salpetriere 25:2232501912


Kothari MGoel A: Transatlantic odonto-occipital listhesis: the so-called basilar invagination. Neurol India 55:672007


Mahajan PVBharucha BA: Evaluation of short neck: new neck length percentiles and linear correlations with height and sitting height. Indian Pediatr 31:119312031994


McRae DL: Bony abnormalities in the region of foramen magnum: correlation of anatomic and neurologic findings. Acta Radiol 40:3353541953


Menezes AH: Primary craniovertebral anomalies and hindbrain herniation syndrome (Chiari I): data base analysis. Pediatr Neurosurg 23:2602691995


Thiebaut FWackenheim AVrousos C: [New median sagittal pneumostratigraphical findings concering the posterior fossa.]. J Radiol Electrol Med Nucl 42:171961. (Fr)


VanGilder JCMenezes AHDolan KA: The Craniovertebral Junction and Its Abnormalities Mount Kisco, NYFutura1987. 2968


Von Torklus DGehle W: The Upper Cervical Spine: Regional Anatomy Pathology and Traumatology. A Systematic Radiological Atlas and Textbook New YorkGrune & Stratton1972. 198


Virchow R: Beitrage zur physischen Anthropologie der Deutschen mit besonderer Berucksichtigung der Friesen BerlinAbhandlungen de Koniglichen Akademie der Wissenschaften1876




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