title: The effect of implant placement on sacroiliac joint range of motion: posterior versus transarticular.
abstract: METHODS
  A human cadaveric biomechanical study of 2 sacroiliac (SI) joint fusion implant placement techniques.
  
  
  OBJECTIVE
  To evaluate and compare the biomechanical properties of 2 implant placement techniques for SI joint fusion.
  
  
  BACKGROUND
  Minimally invasive placement of SI joint fusion implants is a potential treatment of SI joint disruptions and degenerative sacroiliitis. Biomechanical studies of screw fixation within the sacrum have shown that placement and trajectory are important in the overall stability of the implant. Although clinical results have been promising, there is the possibility that a more optimal arrangement of implants may exist.
  
  
  METHODS
  Bilateral SI joints in 7 cadaveric lumbopelvic (L4-pelvis) specimens were tested using a single leg stance model. All joints were tested intact, pubic symphysis sectioned, and treated (3 SI joint fusion implants). The implants were laterally placed using either a posterior or transarticular placement technique. The posterior technique places the implants inline in the inlet view, parallel in the outlet view, and parallel to the posterior sacral body in the lateral view. The transarticular technique places all implants across the articular portion of the SI joint. For all conditions, the range of motion was tested in flexion-extension, lateral bending, and axial rotation.
  
  
  RESULTS
  The posterior technique significantly reduced the range of motion in flexion-extension, lateral bending, and axial rotation by 27% ± 24% (P = 0.024), 28% ± 26% (P = 0.028), and 32% ± 21% (P = 0.008), respectively. The transarticular technique significantly reduced the range of motion in flexion-extension, lateral bending, and axial rotation by 41% ± 31% (P = 0.013), 36% ± 38% (P = 0.049), and 36% ± 28% (P = 0.015), respectively. No significant differences were detected between the posterior and transarticular placement techniques (P > 0.25).
  
  
  CONCLUSIONS
  Posterior and transarticular placement of SI joint fusion implants stabilized the SI joint in flexion-extension, lateral bending, and axial rotation.
  
  
  METHODS
  N/A.
authors.affiliation: *Spinal Biomechanics Research Laboratory, Barrow Neurological Institute, St. Joseph's Hospital & Medical Center, Phoenix, AZ; and †SI-BONE, Inc., San Jose, CA.
authors.forename: Hector
authors.initials: H
authors.lastname: Soriano-Baron
authors.forename: Derek P
authors.initials: DP
authors.lastname: Lindsey
authors.forename: Nestor
authors.initials: N
authors.lastname: Rodriguez-Martinez
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Reyes
authors.forename: Anna
authors.initials: A
authors.lastname: Newcomb
authors.forename: Scott A
authors.initials: SA
authors.lastname: Yerby
authors.forename: Neil R
authors.initials: NR
authors.lastname: Crawford
mesh_terms: D000328:Adult; D000368:Aged; D019643:Arthroplasty, Replacement / Q000379:methods*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D016059:Range of Motion, Articular / Q000502:physiology*; D012446:Sacroiliac Joint / Q000502:physiology* / Q000601:surgery*; D055815:Young Adult