title: Analysis of the causes of recurrence after frontalis suspension using silicone rods for congenital ptosis.
abstract: BACKGROUND
  Silicone rod is a commonly used synthetic suspension material in frontalis suspension surgery to correct blepharoptosis. The most challenging problem and a decisive drawback of the use of silicone rod is a considerable rate of ptosis recurrence after surgery. We examined patients with recurred ptosis and assessed the physical and micromorphological properties of implanted silicone rods to determine the causative mechanisms of recurred ptosis after frontalis suspension using silicone rod.
  
  
  METHODS
  This is a prospective observational case series of 22 pediatric patients with recurred ptosis after frontalis suspension using silicone rods for congenital ptosis. Implanted silicone rods were observed and removed during the operation for correction of recurred ptosis. The removed silicone rods were physically and micromorphologically evaluated to determine the cause of recurrence.
  
  
  RESULTS
  Pretarsal fixation positions migrated upward, whereas suprabrow fixation positions migrated downward during ptosis recurrence. The breaking strength of implanted silicone rods was reduced by approximately 50% during 3 years. Cracks, debris, and loss of homogenous structure with disintegration were observed on scanning electron micrographs of implanted silicone rods in patients with recurred ptosis. Preoperative severe degree of ptosis also contributed to recurred ptosis.
  
  
  CONCLUSIONS
  Recurrence of ptosis after frontalis suspension using silicone rod was associated with physical changes of implanted silicone rods, including positional migration, weakened tensile strength, and micromorphological changes in combination with patients' characteristics.
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.|Department of Ophthalmology, Kim's Eye Hospital, Myung-Gok Eye Research Institute, Konyang University College of Medicine, Seoul, Korea.
authors.forename: Chang Yeom
authors.initials: CY
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, School of Medicine, Kyungpook National University, Daegu, Korea.
authors.forename: Byeong Jae
authors.initials: BJ
authors.lastname: Son
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, Seoul, Korea.|Mechanical Science and Engineering, University of Illinois at Urbana-Champaign (UIUC), Urbana, Illinois, United States of America.
authors.forename: Jangyup
authors.initials: J
authors.lastname: Son
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, Seoul, Korea.
authors.forename: Jongill
authors.initials: J
authors.lastname: Hong
authors.affiliation: The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.|Lee's Eye Clinic, Seoul, Korea.
authors.forename: Sang Yeul
authors.initials: SY
authors.lastname: Lee
mesh_terms: D001672:Biocompatible Materials / Q000009:adverse effects*; D001763:Blepharoptosis / Q000151:congenital / Q000473:pathology* / Q000601:surgery; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008422:Materials Testing; D011446:Prospective Studies; D019736:Prostheses and Implants / Q000009:adverse effects*; D012008:Recurrence; D012828:Silicones
chemical_list: D001672:Biocompatible Materials; D012828:Silicones