title: Correction of orbital wall fracture close to the optic canal using computer-assisted navigation surgery.
abstract: BACKGROUND
  Repairing orbital wall fractures can result in serious complications, including enophthalmos, diplopia, or even blindness. Especially, surgeons worry about damaging the optic nerve while dissecting the optic canal area. We avoid these complications by using a navigation system that was adapted to stereotactic concept based on three-dimensional imaging of the patient's anatomy. Here, we report 5 cases of orbital wall fracture that were repaired using a navigation system.
  
  
  METHODS
  The Navigation System II (Stryker, Freiburg, Germany) and the iNtellect Cranial Navigation (version 1.1) platform were used for each operation. A computer-assisted navigation surgery was performed according to the following procedures: (1) image set, (2) planning, (3) apparatus setup, (4) registration, and (5) intraoperative navigation. Operations were performed under general anesthesia. Dissection was performed up to the periosteum immediately anterior to the optic canal, near the fracture. Vulnerable surrounding structures were identified with the intraoperative pointer. After navigation, we inserted an implant into the defect, successfully, avoiding damage to the optic canal and optic nerve.
  
  
  RESULTS
  None of the patients had any surgical complications. Postoperative computed tomography scans demonstrated that the fractures were corrected, and continuity was maintained without displacement. The three-dimensional image allowed us to easily visualize intraoperative anatomical structure, allowing us to avoid unnecessary procedures and to correct the orbital wall. The mean volume of fractured orbital cavity was 29.2 cm(3) (range, 28.3-30.4 cm(3)) preoperatively and 27.0 cm(3) (range, 25.9-28.5 cm(3)) postoperatively; thus, the defects were corrected by 2.2 cm(3) (range, 1.3-2.8 cm(3)) on average.
  
  
  CONCLUSIONS
  We used a navigation system to perform accurate and safe surgery in patients with extensive orbital wall fracture, including around the optic canal. By using the functions to visualize the locations indicated by the pointer, we were able to perform successful dissections and implantations in areas adjacent to the optic canal. The good outcomes obtained here provide evidence that surgical correction of the orbital wall using a navigation system is useful in cases of deep, extensive orbital wall fracture.
authors.affiliation: Department of Plastic and Reconstructive Surgery, College of Medicine, Yeungnam University, Daegu, Korea.
authors.forename: Yong-Ha
authors.initials: YH
authors.lastname: Kim
authors.forename: Dong-Woo
authors.initials: DW
authors.lastname: Jung
authors.forename: Tae Gon
authors.initials: TG
authors.lastname: Kim
authors.forename: Jun Ho
authors.initials: JH
authors.lastname: Lee
authors.forename: Il-Kug
authors.initials: IK
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D003198:Computer Simulation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008297:Male; D008875:Middle Aged; D009917:Orbital Fractures / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D055815:Young Adult