title: Craniocervical instability in an infant with partial sacral agenesis.
abstract: Sacral agenesis is an uncommon condition characterised by total or partial absence of the sacrum. The association of this condition with craniocervical junction abnormalities is extremely rare.
  
  
  METHODS
  We describe a 3-year-old girl who, at the age of 8 months, while being investigated for short stature, was found to have significant craniocervical instability associated with anomalies of the odontoid peg. In addition to this she had partial sacral agenesis but genetic tests showed a normal karyotype. Due to the inherent difficulty of surgical fixation and immobilisation in an infant of her age, she was managed conservatively in a soft cervical orthosis. At the age of three years, surgery for decompression and stabilisation was deemed necessary due to the onset of neurological morbidity.
  
  
  CONCLUSIONS
  The authors describe this extremely rare association and discuss the difficulties faced while deciding the optimum surgical strategy for managing such young children with craniocervical instability.
authors.affiliation: Department of Neurosurgery, Royal Manchester Children's Hospital, Manchester, UK.
authors.forename: W A
authors.initials: WA
authors.lastname: Thiryayi
authors.forename: L M
authors.initials: LM
authors.lastname: Alakandy
authors.forename: P A
authors.initials: PA
authors.lastname: Leach
authors.forename: R A
authors.initials: RA
authors.lastname: Cowie
mesh_terms: D000015:Abnormalities, Multiple / Q000000981:diagnostic imaging / Q000601:surgery*; D001268:Atlanto-Axial Joint / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D016025:Bone Transplantation; D002574:Cervical Vertebrae / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D002675:Child, Preschool; D019465:Craniofacial Abnormalities / Q000175:diagnosis; D019299:Decompression, Surgical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007223:Infant; D004204:Joint Dislocations / Q000151:congenital* / Q000175:diagnosis / Q000601:surgery; D007593:Joint Instability / Q000151:congenital* / Q000175:diagnosis / Q000601:surgery; D008279:Magnetic Resonance Imaging; D009421:Nervous System Malformations / Q000175:diagnosis / Q000601:surgery*; D009777:Occipital Bone / Q000473:pathology / Q000601:surgery; D009809:Odontoid Process / Q000002:abnormalities* / Q000473:pathology / Q000601:surgery; D012447:Sacrum / Q000002:abnormalities* / Q000473:pathology; D013117:Spinal Cord Compression / Q000175:diagnosis / Q000601:surgery; D013123:Spinal Fusion; D014057:Tomography, X-Ray Computed