title: Skull base cephalometric changes in cranial expansion by springs.
abstract: BACKGROUND
  The use of springs in cranial expansion has demonstrated to be effective for craniosynostosis treatment. The spring-exerted expansile action has been observed when springs are placed both in the sagittal and parasagittal regions, mainly in scaphocephaly. In this study, a variation in cephalometric measurements under expansible spring action on the skull base was analyzed.
  
  
  METHODS
  Thirteen 4-week-old New Zealand white rabbits were divided into 4 groups: group 1, in which only amalgam markers were used (control); group 2, in which amalgam markers were used, and a sagittal suturectomy was performed; group 3, in which amalgam markers were used, and a sagittal suturectomy was performed with placement of expansible springs in the interparietal region; and group 4, in which markers were used, and a linear parasagittal craniectomy was performed with spring placement. All animals were killed at weeks 2, 4, 8, and 12. Radiologic control with cephalometric study was performed.
  
  
  RESULTS
  Distraction of amalgam markers in the groups with springs was greater than in those without springs. A proportional change in the angles measured through craniometry was observed in these groups.
  
  
  CONCLUSIONS
  The experimental rabbit model was shown to be adequate to the analysis proposed by the study. Under the action of springs, the groups with sagittal and parasagittal osteotomy were found to present a similar distraction of amalgam markers. A concomitant change in cephalometric measurements occurred, suggesting a change in the skull base mediated by expansible springs placed both in the sutural and nonsutural sites.
authors.affiliation: São Paulo University Medical School, São Paulo, Brazil. rodrigo@npa.med.br
authors.forename: Rodrigo
authors.initials: R
authors.lastname: de Faria Valle Dornelles
authors.forename: Vera Lúcia Nocchi
authors.initials: VL
authors.lastname: Cardim
authors.forename: Ana Carolina Brandão
authors.initials: AC
authors.lastname: de Campos Fonseca Pinto
authors.forename: Nivaldo
authors.initials: N
authors.lastname: Alonso
mesh_terms: D000818:Animals; D002508:Cephalometry / Q000379:methods*; D002858:Chromium Alloys / Q000737:chemistry; D003393:Cranial Sutures / Q000601:surgery; D003399:Craniotomy / Q000295:instrumentation / Q000379:methods; D055119:Elastic Modulus; D004867:Equipment Design; D005260:Female; D057918:Fiducial Markers; D007091:Image Processing, Computer-Assisted / Q000379:methods; D023421:Models, Animal; D009969:Orthodontic Wires; D019857:Osteogenesis, Distraction / Q000295:instrumentation* / Q000379:methods; D010294:Parietal Bone / Q000601:surgery; D011817:Rabbits; D012886:Skull / Q000033:anatomy & histology*; D019291:Skull Base / Q000033:anatomy & histology; D013314:Stress, Mechanical; D013997:Time Factors
chemical_list: D002858:Chromium Alloys