title: [Human umbilical cord used for wrapping hydroxyapatite orbital implant--animal experiment and clinical observation].
abstract: OBJECTIVE
  Hydroxyapatite (HA) sphere is admitted to be the best orbital implant today, but it can cause some complications, such as conjunctival erosion and implant exposure. The causes of these complications include HA's mechanical and chemical stimulation to the conjunctiva. In order to protect conjunctiva against HA's invasion, most authors suggest wrapping the HA sphere with some material. The wrapping materials usually are autogenous or heterogeneous sclera or fascia. These materials are either unavailable or unaccepted by patients. This study was made on human umbilical cord tissue as the wrapping material of HA sphere.
  
  
  METHODS
  Hydroxyapatite spheres enveloped in human umbilical cord tissue were inserted in ten rabbits' orbits. At 1, 2 weeks and 1, 2, 3, 6, 8, 10, 12 and 14 months after implantation, the conjunctival sac was examined. Then the HA sphere was removed and examined with a scanning electron microscope. Fifteen patients received HA orbital implants enveloped in human umbilical cord from September 1996 To December 1997. The pre- and post-operative photographs of the sockets, the implant motility were analysed.
  
  
  RESULTS
  The animal experiment showed that the umbilical cord was tightly adherent to the HA sphere and orbital tissue. The fibro-vascular tissue gradually invaded the interconnecting pores of the sphere after implantation. None of the 15 patients had orbital infection or implant extrusion during an average follow-up of 10 months (range of 8-12 months). Three patients had conjunctival erosion, which was well treated. All patients have cosmetically satisfactory motility of the prosthesis.
  
  
  CONCLUSIONS
  Human umbilical cord tissue can be used as wrapping material of hydroxyapatite orbital implant.
authors.affiliation: Department of Ophthalmology, First Hospital, Jiangxi Medical College, Nanchang 330006, China.
authors.forename: L
authors.initials: L
authors.lastname: Chen
authors.forename: Q
authors.initials: Q
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D002648:Child; D017886:Durapatite; D015353:Eye Enucleation; D005137:Eye, Artificial; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D020273:Orbital Implants; D011817:Rabbits; D014470:Umbilical Cord / Q000637:transplantation*
chemical_list: D017886:Durapatite