Background: Achondroplasia is the commonest form of human dwarfism. The authors report atlanto-axial instability, in consequence to os odontoideum in this subgroup of patients. Methods: Two achondroplastic dwarfs harboring atlanto-axial dislocation are described along with radiological findings. Results: Both children underwent successful internal rigid immobilization, using sublaminar atlanto-axial wiring. Conclusions: Craniovertebral junction instability should be evaluated among these children, whenever foramen magnum insufficiency is being considered.

Keywords:
Achondroplasia, Atlanto-axial dislocation, Os odontoideum
1.
Orioli IM, Castilla EE, Barbosa-Neto JG: The birth prevalence rates for the skeletal dysplasias. J Med Genet 1986;23:328–332.
2.
King JA, Vachhrajani S, Drake JM, Rutka JT: Neurosurgical implications of achondroplasia. J Neurosurg Pediatr 2009;4:297–306.
3.
Morgan DF, Young RF: Spinal neurological complications of achondroplasia. Results of surgical treatment. J Neurosurg 1980;52:463–472.
4.
Gulati DR, Rout D: Atlantoaxial dislocation with quadriparesis in achondroplasia. Case report. J Neurosurg 1974;40:394–396.
5.
Yukata K, Katoh S, Sairyo K, Matsui Y, Hamada Y, Yasui N: Os odontoideum in achondroplasia: a case report. J Pediatr Orthop B 2008;17:103–105.
6.
Donath J, Vogl A: Untersuchungen über den chondrodystrophischen Zwergwuchs. Wien Arch Inn Med 1925;10:1–44.
7.
Hammerschlag W, Ziv I, Wald U, Robin GC, Floman Y: Cervical instability in an achondroplastic infant. J Pediatr Orthop 1988;8:481–484.
8.
Ryken TC, Menezes AH: Cervicomedullary compression in achondroplasia. J Neurosurg 1994;81:43–48.
9.
Benglis DM, Sandberg DI: Acute neurological deficit after minor trauma in an infant with achondroplasia and cervicomedullary compression. Case report and review of the literature. J Neurosurg 2007;107:152–155.
10.
Waters KA, Everett F, Sillence D, Fagan E, Sullivan CE: Breathing abnormalities in sleep in achondroplasia. Arch Dis Child 2003;69:191–196.
11.
Danielpour M, Wilcox WR, Alanay Y, Pressman BD, Rimoin DL: Dynamic cervicomedullary cord compression and alterations in cerebrospinal fluid dynamics in children with achondroplasia. Report of four cases. J Neurosurg 2007;107:504–507.
12.
Dai L, Yuan W, Ni B, Jia L: Os odontoideum: etiology, diagnosis, and management. Surg Neurol 2000;53:106–109.
13.
Segev O, Chumakov I, Nevo Z, Givol D, Madar-Shapiro L, Sheinin Y, Weinreb M, Yayon A: Restrained chondrocyte proliferation and maturation with abnormal growth plate vascularization and ossification in human FGFR-3(G380R) transgenic mice. Hum Mol Genet 2000;9:249–258.
© 2012 S. Karger AG, Basel
2012
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