title: [Evaluation of the navigation system for orbital wall reconstruction in unilateral orbital fractures].
abstract: OBJECTIVE
  To evaluate the efficiency of navigation system for orbital wall reconstruction in unilateral orbital fractures.
  
  
  METHODS
  Fifteen patients (7 male and 8 female) with unilateral orbital fracture underwent orbital reconstruction with the help of intraoperative navigation system. The average age was 34.3 ± 9.5 years. All patients underwent spiral CT scanning preoperatively, and the CT data was imported to the BrainLab navigation system (Germany, BrainLab company). The orbit of the intact side was mirrored to the opposite side as the reference for pre-operative planning. The titanium mesh was mounted on the resin template made by rapid prototyping machine based on the mirrored CT data. When the injury was limited, the hydroxyapatite sheet was used for the orbital wall reconstruction. During the operation, the real-time navigation helped to ensure precise placement. The re-establishing result was assessed based on the postoperative CT data with the following four variables: the volumetric difference between the bilateral orbit, the volume of the herniated soft tissue, the global projection and the discrepancy between the simulated and the achieved position of the reconstructed orbital wall. The reconstructive discrepancy was measured only in the titanium plate grafting cases.
  
  
  RESULTS
  There were no serious complications such as infection, graft rejection and optic nerve injury in any case. Preoperatively, the average degree of enophthalmos was (3.5 ± 1.6) mm, the average volumetric difference between the injured and the unaffected orbit was (4.5 ± 1.8) ml, and the average volume of the herniated orbital soft tissue was (2.1 ± 0.7) ml. Postoperatively, the three values were respectively reduced to (1.3 ± 0.6) mm, (1.8 ± 0.9) ml and (0.7 ± 0.3) ml. The discrepancy of the medial and inferior wall were (2.5 ± 0.6) mm and (2.1 ± 0.4) mm.
  
  
  CONCLUSIONS
  The intraoperative use of navigation system for the orbital wall reconstruction in unilateral orbital fractures can provide reliable accuracy and achieve satisfactory results.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China.
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Zhang
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Feng
authors.forename: Xi
authors.initials: X
authors.lastname: Gong
authors.forename: Yang
authors.initials: Y
authors.lastname: He
authors.forename: Jin-Gang
authors.initials: JG
authors.lastname: An
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000328:Adult; D003198:Computer Simulation; D015841:Enophthalmos / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D005260:Female; D006801:Humans; D008297:Male; D009915:Orbit / Q000000981:diagnostic imaging / Q000601:surgery; D009917:Orbital Fractures / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D019651:Plastic Surgery Procedures / Q000379:methods*; D025321:Surgery, Computer-Assisted; D013526:Surgical Mesh; D014025:Titanium; D014057:Tomography, X-Ray Computed
chemical_list: D014025:Titanium