title: Minimally invasive versus open sacroiliac joint fusion: are they similarly safe and effective?
abstract: BACKGROUND
  The sacroiliac joint has been implicated as a source of chronic low back pain in 15% to 30% of patients. When nonsurgical approaches fail, sacroiliac joint fusion may be recommended. Advances in intraoperative image guidance have assisted minimally invasive surgical (MIS) techniques using ingrowth-coated fusion rods; however, how these techniques perform relative to open anterior fusion of the sacroiliac joint using plates and screws is not known.
  
  
  OBJECTIVE
  We compared estimated blood loss (EBL), surgical time, length of hospital stay (LOS), and Oswestry Disability Index (ODI) between patients undergoing MIS and open sacroiliac joint fusion.
  
  
  METHODS
  We retrospectively studied 63 patients (open: 36; MIS: 27) who underwent sacroiliac joint fusion with minimum 1-year followup at our institution from 2006 to 2011. Of those, 10 in the open group had incomplete records. All patients had sacroiliac joint dysfunction confirmed by image-guided intraarticular anesthetic sacroiliac joint injection and had failed nonoperative treatment. Patients were matched via propensity score, adjusting for age, sex, BMI, history of spine fusion, and preoperative ODI scores, leaving 22 in each group. Nine patients were not matched. We reviewed patient medical records to obtain EBL, length of surgery, LOS, and pre- and postoperative ODI scores. Mean followup was 13 months (range, 11-33 months) in the open group and 15 months (range, 12-26 months) in the MIS group.
  
  
  RESULTS
  Patients in the open group had a higher mean EBL (681 mL versus 41 mL, p < 0.001). Mean surgical time and LOS were shorter in the MIS group than in the open group (68 minutes versus 128 minutes and 3.3 days versus 2 days, p < 0.001 for both). With the numbers available, mean postoperative ODI scores were not different between groups (47% versus 54%, p = 0.272).
  
  
  CONCLUSIONS
  EBL, surgery time, and LOS favored the MIS sacroiliac fusion group. With the numbers available, ODI scores were similar between groups, though the study size was relatively small and it is possible that the study was underpowered on this end point. Because the implants used for these procedures make assessment of fusion challenging with available imaging techniques, we do not know how many patients' sacroiliac joints successfully fused, so longer followup and critical evaluation of outcomes scores over time are called for.
  
  
  METHODS
  Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
authors: Department of Orthopaedic Surgery, University of Minnesota, 2450 Riverside Avenue, South R200, Minneapolis, MN, 55454, USA, ledon001@umn.edu.
authors: Charles G T
authors: CG
authors: Ledonio
authors: David W
authors: DW
authors: Polly
authors: Marc F
authors: MF
authors: Swiontkowski
mesh_terms: D000328:Adult; D016063:Blood Loss, Surgical; D001860:Bone Plates; D001863:Bone Screws; D059350:Chronic Pain / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007902:Length of Stay; D017116:Low Back Pain / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019060:Minimally Invasive Surgical Procedures; D061646:Operative Time; D010147:Pain Measurement; D018579:Patient Selection; D011183:Postoperative Complications / Q000209:etiology; D057216:Propensity Score; D011474:Prosthesis Design; D012189:Retrospective Studies; D012307:Risk Factors; D012446:Sacroiliac Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome