title: Spring-assisted surgery-a surgeon's manual for the manufacture and utilization of springs in craniofacial surgery.
abstract: OBJECTIVE
  Spring-assisted surgery has been used for the treatment of craniofacial deformities since its 1997 inception in Sweden by Dr Lauritzen (Scand J Plast Reconstr Surg Hand Surg 1998;32:331-338). Initial applications have focused on the treatment of patients with single-suture craniosynostosis. Recently, indications and applications have expanded to include patients with syndromic craniosynostosis, multiple-suture synostosis, and midface hypoplasia. The advancement of spring-assisted surgery in this country has been hindered by the need for patient-specific spring fabrication because few surgeons understand how to make the springs for each application. We will review our spring design and treatment algorithms to facilitate wider use of this innovative treatment modality.
  
  
  METHODS
  This is a retrospective institutional review board-approved analysis of the spring design for our first 90 cases of spring-assisted surgery used to treat sagittal synostosis at the North Carolina Center for Cleft and Craniofacial Deformities. Outcome analysis was done to generate a treatment algorithm based on diagnosis, patient age, spring design, number of springs, spring force and expansion, and clinical outcome.
  
  
  RESULTS
  Ninety children with sagittal craniosynostosis (64 males, 26 females) were treated during an 8-year period (2001-2009) with spring-assisted surgery. Mean age at treatment was 4.4 months and mean age at spring removal was 8.8 months. Mean number of springs used was 2 (range, 1-3). Mean spring force used in sagittal synostosis was 5.5-9.5 (range) for the anterior spring and 5.5-9.5 (range) for the posterior spring with a mean posttreatment expansion of 6.65 cm. Analysis of the results shows that spring force and expansion required for optimal correction is dependent on the age at surgery, type of the deformity, and severity of the deformity. Specifically, the younger the child, the weaker the spring needed for surgical correction. General principles for spring application for scaphocephaly include (1) the longer the anterior posterior dimension of the skull deformity, the more likely a third spring is necessary; (2) the narrower the posterior occiput, the stronger the posterior spring required; and (3) if a postcoronal band is seen in the calvarium, a stronger anterior spring is needed.
  
  
  CONCLUSIONS
  Long-term experience with spring-assisted surgery has facilitated the development of standardized, reproducible techniques allowing spring design modifications to optimize clinical outcome.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Wake Forest University, Winston-Salem, North Carolina 27157, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Pyle
authors.forename: Steven
authors.initials: S
authors.lastname: Glazier
authors.forename: Daniel
authors.initials: D
authors.lastname: Couture
authors.forename: Claire
authors.initials: C
authors.lastname: Sanger
authors.forename: Stan
authors.initials: S
authors.lastname: Gordon
authors.forename: Lisa
authors.initials: L
authors.lastname: David
mesh_terms: D003393:Cranial Sutures / Q000601:surgery*; D003398:Craniosynostoses / Q000601:surgery*; D003399:Craniotomy / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D019736:Prostheses and Implants; D019651:Plastic Surgery Procedures / Q000295:instrumentation; D012189:Retrospective Studies; D013314:Stress, Mechanical