title: Surgical exposures and options for instrumentation in acetabular fracture fixation: Pararectus approach versus the modified Stoppa.
abstract: BACKGROUND
  As an alternative to the modified Stoppa approach, the Pararectus approach is used clinically for treatment of acetabular fractures involving the anterior column. The current study assessed the surgical exposure and the options for instrumentation using both of these approaches.
  
  
  METHODS
  Surgical dissections were conducted on five human cadavers (all male, mean age 88 years (82-97)) using the modified Stoppa and the Pararectus approach, with the same skin incision length (10cm). Distal boundaries of the exposed bony surfaces were marked using a chisel. After removal of all soft-tissues, distances from the boundaries in the false and true pelvis were measured with reference to the pelvic brim. The exposed bone was coloured and calibrated digital images of each inner hemipelvis were taken. The amount of exposed surface using both approaches was assessed and represented as a percentage of the total bony surface of each hemipelvis. For instrumentation, a suprapectineal quadrilateral buttress plate was used. Screw lengths were documented, and three-dimensional CT reconstructions were performed to assess screw trajectories qualitatively. Wilcoxon's signed rank test for paired groups was used (level of significance: p<0.05).
  
  
  RESULTS
  After utilization of the Pararectus approach, the distances from the farthest boundaries of exposed bone towards the pelvic brim were significantly higher in the false but not the true pelvis, compared to the modified Stoppa approach. The percentage (mean±SD) of exposed bone accessible after utilizing the Pararectus approach was 42±8%, compared to 29±6% using the modified Stoppa (p=0.011). In cadavers exposed by the Pararectus approach, screws placed for posterior fixation and as a posterior column screw were longer by factor 1.8 and 2.1, respectively (p<0.05), and screws could be placed more posteromedial towards the posterior inferior iliac spine or in line with the posterior column directed towards the ischial tuberosity.
  
  
  CONCLUSIONS
  Compared to the modified Stoppa, the Pararectus approach facilitates a greater surgical access in the false pelvis, provides versatility for fracture fixation in the posterior pelvic ring and allows for the option to extend the approach without a new incision.
authors: Department of Orthopaedic and Trauma Surgery, University of Bern, Inselspital, Freiburgstrasse 3, 3010 Bern, Switzerland; Institute of Anatomy, University of Bern, Switzerland. Electronic address: johannes.bastian@insel.ch.
authors: J D
authors: JD
authors: Bastian
authors: Institute of Anatomy, University of Bern, Switzerland.
authors: M
authors: M
authors: Savic
authors: Department of Diagnostic, Interventional and Paediatric Radiology, University of Bern, Inselspital, Freiburgstrasse 3, 3010 Bern, Switzerland.
authors: J L
authors: JL
authors: Cullmann
authors: Institute of Forensic Medicine, Department of Forensic Medicine and Imaging, University of Bern, Switzerland.
authors: W D
authors: WD
authors: Zech
authors: Institute of Anatomy, University of Bern, Switzerland.
authors: V
authors: V
authors: Djonov
authors: Department of Orthopaedic and Trauma Surgery, University of Bern, Inselspital, Freiburgstrasse 3, 3010 Bern, Switzerland.
authors: M J
authors: MJ
authors: Keel
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology / Q000473:pathology / Q000601:surgery*; D000369:Aged, 80 and over; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D004210:Dissection / Q000379:methods; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D008297:Male; D010384:Pelvic Bones / Q000033:anatomy & histology / Q000473:pathology / Q000601:surgery*; D014057:Tomography, X-Ray Computed
keywords: Acetabulum; Exposure; Fracture; Modified Stoppa; Pararectus