title: Fusion of Multiple Segments Can Increase the Incidence of Sacroiliac Joint Pain After Lumbar or Lumbosacral Fusion.
abstract: METHODS
  A retrospective study.
  
  
  OBJECTIVE
  To determine the risk factors for sacroiliac joint pain (SIJP) after lumbar or lumbosacral fusion.
  
  
  BACKGROUND
  Recently, the sacroiliac joint has gained increased attention as a source of pain after lumbar or lumbosacral fusion. We examined the factors related to the development of SIJP after lumbar or lumbosacral fusion.
  
  
  METHODS
  In total, 262 patients who underwent lumbar or lumbosacral fusion from June 2006 to June 2009 were included in this study. All patients who did not show SIJP clinically in the preoperative screening period were considered. Of these patients, 28 newly developed SIJP. We investigated whether development of SIJP after lumbar or lumbosacral fusion is related to the presence of fusion involving the sacrum (floating fusion vs. fixed fusion) and the number of fused segments.
  
  
  RESULTS
  The incidence of SIJP was higher with fixed fusion (13.1%) than with floating fusion (10.0%). With regard to the number of fused segments, the incidence of SIJP was 5.8% for one fused segment, 10.0% for two segments, 20.0% for three segments, 22.5% for at least four segments. Thus, the incidence was significantly higher when at least three segments were fused. Logistic regression analysis was performed to determine if the development of SIJP was related to the presence of fusion involving the sacrum or the number of fused segments. The analysis revealed that the number of fused segments was significantly associated with the development of SIJP.
  
  
  CONCLUSIONS
  SIJP is a potential cause of low back pain after lumbar or lumbosacral fusion surgeries. Our study indicated that fusion of multiple segments (at least three) can increase the incidence of SIJP after lumbar or lumbosacral fusion.
  
  
  METHODS
  Level 3.
authors.affiliation: From the Department of Orthopedic Surgery, Akita Kousei Medical Center, Nishifukuro, Akita, Japan.
authors.forename: Eiki
authors.initials: E
authors.lastname: Unoki
authors.forename: Eiji
authors.initials: E
authors.lastname: Abe
authors.forename: Hajime
authors.initials: H
authors.lastname: Murai
authors.forename: Takashi
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Toshiki
authors.initials: T
authors.lastname: Abe
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018771:Arthralgia / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010149:Postoperative Pain / Q000175:diagnosis* / Q000209:etiology; D012189:Retrospective Studies; D012446:Sacroiliac Joint; D012447:Sacrum / Q000601:surgery*; D013123:Spinal Fusion / Q000009:adverse effects* / Q000639:trends; D055815:Young Adult