title: Complications of motility peg placement for the hydroxyapatite orbital implant.
abstract: OBJECTIVE
  The hydroxyapatite implant is an ocular motility implant designed to provide natural movement of the artificial eye. The movement of the prosthesis is maximized when the implant is coupled to the prosthesis via a peg. The purpose of this study is to determine the complications of the hydroxyapatite motility peg and the factors related to those complications.
  
  
  METHODS
  Retrospective review of 47 cases over 5 years.
  
  
  METHODS
  A retrospective review was performed on all cases of hydroxyapatite motility peg placement. The technique of hydroxyapatite and peg placement, follow-up details, and complications of the peg were recorded.
  
  
  RESULTS
  The complications of peg placement included peg extrusion in 26% (12 of 47), nonspecific conjunctivitis in 6% (3 of 47), audible click in 6% (3 of 47), temporary excessive conjunctival edema in 4% (2 of 47), and temporary excessive postoperative pain in 4% (2 of 47). There were no cases of infection, persistent pain, persistent edema, or discharge at peg site. The median time interval from peg placement to extrusion was 16 months (range, 1-52 months). The only statistically significant factor related to peg extrusion was age over 50 years (P = 0.04). There was a trend toward peg extrusion with use of a nonsleeved peg (versus sleeved peg) (P = 0.10). The extrusion rate was 32% (12 of 38) for nonsleeved pegs and 0% (0 of 9) for sleeved pegs. Factors unrelated to peg extrusion were patient sex, prior ocular surgery or radiotherapy, presence of giant papillary conjunctivitis, time interval from enucleation to peg placement, and degree of implant vascularization on magnetic resonance imaging. Of the 12 nonsleeved pegs that extruded, a sleeved peg system was subsequently successfully placed in 5 patients, a nonsleeved peg in 1 patient, and 6 patients remained without a peg system.
  
  
  CONCLUSIONS
  Hydroxyapatite motility pegs have relatively few complications except for extrusion. The rate of extrusion can be minimized by employing a sleeved peg rather than a nonsleeved peg system.
authors.affiliation: Ocular Oncology Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
authors.forename: C
authors.initials: C
authors.lastname: Edelstein
authors.forename: C L
authors.initials: CL
authors.lastname: Shields
authors.forename: P
authors.initials: P
authors.lastname: De Potter
authors.forename: J A
authors.initials: JA
authors.lastname: Shields
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001672:Biocompatible Materials / Q000009:adverse effects*; D002648:Child; D003229:Conjunctival Diseases / Q000209:etiology; D003231:Conjunctivitis / Q000209:etiology; D017886:Durapatite / Q000009:adverse effects*; D004487:Edema / Q000209:etiology; D015353:Eye Enucleation; D005133:Eye Movements; D005260:Female; D005548:Foreign-Body Migration / Q000209:etiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009915:Orbit / Q000601:surgery*; D010149:Postoperative Pain / Q000209:etiology; D019736:Prostheses and Implants / Q000009:adverse effects*; D012189:Retrospective Studies
chemical_list: D001672:Biocompatible Materials; D017886:Durapatite