title: Radiographic and Clinical Results of Freehand S2 Alar-Iliac Screw Placement for Spinopelvic Fixation: An Analysis of 45 Consecutive Screws.
abstract: METHODS
  This was a retrospective clinical case series.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate mid-term outcomes of S2 ala-iliac (S2AI) screw fixation in patients who underwent multilevel posterior spinal fusion surgery.
  
  
  BACKGROUND
  There have been few reports on radiographic and clinical outcomes in patients who underwent spinopelvic reconstruction surgery using S2AI screw installation.
  
  
  METHODS
  Twenty-three patients were treated by a single spinal surgeon between September 2013 and June 2014 utilizing segmental instrumentation with pedicle and S2AI screw. Instrumentation including S2AI screw was performed by a freehand technique. Surgical, radiographic, clinical outcomes and complications were evaluated to determine surgical results of S2AI screw fixation.
  
  
  RESULTS
  The mean follow-up period was 16.9 months (ranged, 13-22 mo). The average number of fusion levels was 7.9 vertebral bodies. There were no cases of neurological deficit and violation of acetabulum or sciatic notch. A peri-screw halo was found in 1 patient and cortical wall violation was observed in 4 patients. The number of lateral and medial breaches was 2 and 3, respectively. All of them were asymptomatic. One patient experienced sacroiliac joint pain after S2AI screw installation. There was no case of screw/rod fracture and revision surgery for S2AI screw.
  
  
  CONCLUSIONS
  Radiographic and clinical outcomes of freehand S2AI screw fixation was acceptable. Sacroiliac joint irritation symptoms after S2AI screw fixation were rare. S2AI screw instrumentation can be a good alternative for spinopelvic fixation.
  
  
  METHODS
  Level 4.
authors.affiliation: *Department of Neurosurgery, Gyeongsang National University Graduate School of Medicine, Gyeongsang National University Changwon Hospital, Jinju †Department of Neurosurgery, Spine Center, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi ‡Department of Neurosurgery, Hallym University College of Medicine, Kangdong Sacred Heart Hospital, Seoul, South Korea.
authors.forename: Young-Seop
authors.initials: YS
authors.lastname: Park
authors.forename: Seung-Jae
authors.initials: SJ
authors.lastname: Hyun
authors.forename: Jong-Hwa
authors.initials: JH
authors.lastname: Park
authors.forename: Ki-Jeong
authors.initials: KJ
authors.lastname: Kim
authors.forename: Tae-Ahn
authors.initials: TA
authors.lastname: Jahng
authors.forename: Hyun-Jib
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D005260:Female; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging* / Q000601:surgery*; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D010388:Pelvis / Q000000981:diagnostic imaging* / Q000601:surgery*; D013123:Spinal Fusion; D013131:Spine / Q000000981:diagnostic imaging* / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome