title: Evaluation of computer-based volume measurement and porous polyethylene channel implants in reconstruction of large orbital wall fractures.
abstract: OBJECTIVE
  To describe the use of computer-based orbital volume measurement as a predictor of late enophthalmos, and to assess the effectiveness of the MedPor (Porex Surgical Products Group, Newnan, GA) porous polyethylene channel implant to restore orbital volume in repairing large orbital wall fractures.
  
  
  METHODS
  Sixteen patients with unilateral large orbital fractures were included. Computed tomographic (CT) scans were used to obtain computer-based orbital volume measurement to predict the likelihood of late enophthalmos and to assess the change in orbital volume before and after surgery. The effectiveness of a channel implant was evaluated by the orbital volume and postoperative exophthalmetric measurement.
  
  
  RESULTS
  The average time interval between injury and surgery was 17.4 +/- 10 days, and the mean follow-up was 9 months. The orbital volume of the injured orbit was significantly increased (mean, 4.22 +/- 2.61 cm2) compared with the unaffected orbit before surgery (t = 3.046, P = 0.005). There was not a significant difference in orbital volume between the two orbits after orbital reconstruction (t = 0.069, P = 0.945). The orbital volume change after reconstructive surgery was significantly positively correlated with the decrease of enophthalmos (r = 0.715, P = 0.001; enophthalmos [E] = 0.72; volume increment [V] = 0.06). To resolve 2 mm enophthalmos, more than 2.9 cm3 orbital volume augmentation is recommended for early reconstructive surgery. Postoperative CT scan showed most of the channel implants to be well positioned.
  
  
  CONCLUSIONS
  Computer-based orbital volume measurement from a CT scan is useful in the posttraumatic evaluation of orbital fractures, and it can help predict the degree of late enophthalmos that can be expected. Orbital reconstruction with the MedPor channel implant (Porex Surgical Products Group), when indicated, is recommended, especially for large orbital wall fractures.
authors.affiliation: Department of Ophthalmology, the Second Affiliated Hospital of Zhejiang University, College of Medicine, Hangzhou, Zhejiang, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Ye
authors.forename: Koung Hoon
authors.initials: KH
authors.lastname: Kook
authors.forename: Sang Yeul
authors.initials: SY
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D001672:Biocompatible Materials; D001837:Body Weights and Measures; D015841:Enophthalmos / Q000000981:diagnostic imaging*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures; D009915:Orbit / Q000000981:diagnostic imaging*; D009917:Orbital Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D011095:Polyethylenes; D016062:Porosity; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
chemical_list: D001672:Biocompatible Materials; C084562:Medpor; D011095:Polyethylenes