title: Investigation of bone quality of the first and second sacral segments amongst trauma patients: concerns about iliosacral screw fixation.
abstract: BACKGROUND
  Iliosacral screw fixation has become a common method for surgical stabilization of acute disruptions of the pelvic ring. Placement of iliosacral screws into the first sacral (S1) body is the preferred method of fixation, but size limitations and sacral dysmorphism may preclude S1 fixation. In these clinical situations, fixation into the second sacral (S2) body has been recommended. The objective of this study was to evaluate the bone quality of the S1 compared to S2 in the described "safe zone" of iliosacral screw fixation in trauma patients.
  
  
  METHODS
  The pelvic computed tomography scans of 25 consecutive trauma patients, ages 18-49, at a level 1 trauma center were prospectively analyzed. Hounsfield units, a standardized computed tomography attenuation coefficient, was utilized to measure regional cancellous bone mineral density of the S1 and S2. No change in the clinical protocol or treatment occurred as a consequence of inclusion in this study.
  
  
  RESULTS
  A statically significant difference in bone quality was found when comparing the first and second sacral segment (p = 0.0001). Age, gender, or smoking status did not independently affect bone quality.
  
  
  CONCLUSIONS
  In relatively young, otherwise healthy trauma patients there is a statistically significant difference in the bone density of the first sacral segment compared to the second sacral segment. This study highlights the need for future biomechanical studies to investigate whether this difference is clinically relevant. Due to the relative osteopenia in the second sacral segment, which may impact the quality of fixation, we feel this technique should be used with caution.
authors.affiliation: The Department of Orthopaedic Surgery and Rehabilitation, Loyola University Health System, 2160 South First Avenue, Maywood, IL, 60153, USA. dsalazar@post.com.
authors.forename: Dane
authors.initials: D
authors.lastname: Salazar
authors.affiliation: The Department of Orthopaedic Surgery and Rehabilitation, Loyola University Health System, 2160 South First Avenue, Maywood, IL, 60153, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Lannon
authors.affiliation: The Department of Radiology, Loyola University Health System, 2160 South First Avenue, Maywood, IL, 60153, USA.
authors.forename: Olga
authors.initials: O
authors.lastname: Pasternak
authors.affiliation: The Department of Orthopaedic Surgery and Rehabilitation, Loyola University Health System, 2160 South First Avenue, Maywood, IL, 60153, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Schiff
authors.affiliation: The Department of Radiology, Loyola University Health System, 2160 South First Avenue, Maywood, IL, 60153, USA.
authors.forename: Laurie
authors.initials: L
authors.lastname: Lomasney
authors.affiliation: The Department of Orthopaedic Surgery and Rehabilitation, Loyola University Health System, 2160 South First Avenue, Maywood, IL, 60153, USA.
authors.forename: Erika
authors.initials: E
authors.lastname: Mitchell
authors.affiliation: Department of Orthopaedic Surgery, Feinberg School of Medicine, Northwestern University, 676 N. Saint Clair, Suite 1350, Chicago, IL, 60611, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Stover
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density; D001863:Bone Screws; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000000981:diagnostic imaging / Q000293:injuries*; D011446:Prospective Studies; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D014193:Trauma Centers
keywords: Iliosacral screws; Pelvic fracture fixation; Pelvic ring disruptions; Regional bone density