title: Accuracy of computer-assisted iliosacral screw placement using a hybrid operating room.
abstract: BACKGROUND
  In recent years hybrid operating rooms were established all over the world. In our setting we combined a 3D flat-panel c-arm (Artis zeego, Siemens) with a navigation system (BrainLab curve, BrainLab). This worldwide unique combination enables the surgeon to visualise an entire pelvis in CT-like image quality with a single 3D-scan. The aim of our study was to investigate, if utilisation of a hybrid operating room increases the accuracy of SI-screws in comparison to standard 3D-navigation.
  
  
  METHODS
  Retrospective, not randomised single centre case series at a level I trauma centre. Inclusion criterion was insertion of a percutaneous iliosacral screw using image-guidance in the hybrid operating room. 61 patients (35 female, 26 male) were included from June 2012 till October 2014. 65 iliosacral screws were inserted. Intraoperative 3D-scans and postoperative scans were examined to investigate screw placement. The results were compared to a preceding study performed in 2012 using conventional 3D-navigation. Statistical calculations were performed with Microsoft Excel 2011 and SPSS.
  
  
  RESULTS
  65 iliosacral screws were implanted. Two different types of screws were implanted: 1. "Standard" iliosacral screws stabilizing one joint/a unilateral fracture. 2. Single SI-screws stabilizing both SI-joints and if present a bilateral fracture. Forty one patients were included in group 1 (screws n=45). There was no perforation in 43 screws, grade 1 perforation in 2 screws. There was no grade 2 or 3 perforation in this group. Compared to the conventional 3D-navigated screws there was a highly significant difference (p<0.001). Twenty patients could be included in group 2. Eleven screws showed a complete intraosseous position. There was grade 1 perforation in 2 screws, grade 2 perforation in 5 screws and grade 3 perforation in 2 screws.
  
  
  CONCLUSIONS
  Improvements in image quality and enlargement of the display window lead to better intraoperative visualisation of the entire dorsal pelvis. Thereby the accuracy of computer-assisted iliosacral screws could be increased using a hybrid operating room. Furthermore difficult tasks like a single screw for both joints can be accomplished.
authors.affiliation: Ulm University, Department for Orthopaedic Trauma, Hand and Reconstructive Surgery, Albert-Einstein Allee 23, 89081 Ulm, Germany. Electronic address: peter.richter@uniklinik-ulm.de.
authors.forename: P H
authors.initials: PH
authors.lastname: Richter
authors.affiliation: Ulm University, Department for Orthopaedic Trauma, Hand and Reconstructive Surgery, Albert-Einstein Allee 23, 89081 Ulm, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Gebhard
authors.affiliation: Ulm University, Department for Orthopaedic Trauma, Hand and Reconstructive Surgery, Albert-Einstein Allee 23, 89081 Ulm, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Dehner
authors.affiliation: Ulm University, Department for Orthopaedic Trauma, Hand and Reconstructive Surgery, Albert-Einstein Allee 23, 89081 Ulm, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Scola
mesh_terms: D001863:Bone Screws; D005260:Female; D005471:Fluoroscopy; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007085:Ilium / Q000601:surgery; D021621:Imaging, Three-Dimensional; D059032:Learning Curve; D008297:Male; D008875:Middle Aged; D009873:Operating Rooms; D010384:Pelvic Bones / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D012189:Retrospective Studies; D012446:Sacroiliac Joint / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D012447:Sacrum / Q000601:surgery; D025321:Surgery, Computer-Assisted; D016896:Treatment Outcome
keywords: Computer guidance; Computer navigation; Fracture; Hybrid-OR; Iliosacral screw; Intraoperative imaging; Pelvis; Sacral fracture