title: Insertion of psoas minor tendon at pelvic brim, a novel anatomic landmark for extra-articular, screw placement through Stoppa approach.
abstract: BACKGROUND
  The psoas minor partially inserted to the superior pelvic brim. And the plate used to fix the acetabular fracture has always been positioned at the pelvic brim after reduction through the Stoppa approach. However, there are few studies depicting the clinical significance of the psoas minor. The purpose of this paper was to explore the relationship between the insertion of the psoas minor tendon at the pelvic brim (IPMTPB) and screw placement through the Stoppa approach.
  
  
  METHODS
  Fifteen cadavers were dissected for adequate exposure to IPMTPB in our study. However, not all specimens had a psoas minor. For the specimens with IPMTPB, the posterior and anterior edges were used as the first and second entry points, dividing the area from the sacroiliac joint to the pubic symphysis into three zones (d1, d2 and d3). The average proportion of each zone was obtained after measurement the three zones, to locate the two entry points for the specimens without a psoas minor. From the longitudinal Stoppa incision, the first wire was inserted horizontally, and the second wire was placed vertical to the bone surface. Fluoroscopy and computed tomography (CT) were conducted to examine the relationship between the wires and the acetabulum.
  
  
  RESULTS
  There was a psoas minor in sixteen hemipelvises (53.33%). After measurement and calculation, we determined that the average proportions of zones d1, d2, and d3 were 28.03%, 29.14%, and 42.83%, respectively. For all specimens, the wires were successfully inserted, and the trajectories of the wires were outside the hip joint cavity.
  
  
  CONCLUSIONS
  IPMTPB could be used as an anatomic landmark of safe zones for screw placement through the Stoppa approach. For cases without a psoas minor, the zones for extra-articular screw placement could be determined through the measurements in this paper.
authors.affiliation: Third Hospital of Hebei Medical University, Department of Orthopaedic Surgery, Shijiazhuang, Hebei, 050051, China. Electronic address: zhangruipengdoctor@126.com.
authors.forename: Ruipeng
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Third Hospital of Hebei Medical University, Department of Orthopaedic Surgery, Shijiazhuang, Hebei, 050051, China. Electronic address: houzhiyong1234@126.com.
authors.forename: Zhiyong
authors.initials: Z
authors.lastname: Hou
authors.affiliation: Hebei Medical University, Shijiazhuang, Hebei, 050051, China. Electronic address: 323107582@qq.com.
authors.forename: Liping
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Third Hospital of Hebei Medical University, Department of Orthopaedic Surgery, Shijiazhuang, Hebei, 050051, China. Electronic address: dryingchao@gmail.com.
authors.forename: Yingchao
authors.initials: Y
authors.lastname: Yin
authors.affiliation: Third Hospital of Hebei Medical University, Department of Orthopaedic Surgery, Shijiazhuang, Hebei, 050051, China. Electronic address: 845247428@qq.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Third Hospital of Hebei Medical University, Department of Orthopaedic Surgery, Shijiazhuang, Hebei, 050051, China. Electronic address: yzzhangdr@126.com.
authors.forename: Yingze
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology / Q000601:surgery*; D000368:Aged; D000369:Aged, 80 and over; D059925:Anatomic Landmarks; D001863:Bone Screws; D002102:Cadaver; D004210:Dissection / Q000379:methods*; D005260:Female; D005471:Fluoroscopy; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000033:anatomy & histology / Q000601:surgery*
keywords: Extra-articular; Insertion of the psoas minor tendon at the pelvic brim (IPMTPB); Pelvic brim; Screw placement; Stoppa