title: Revision lumbar arthrodesis for the treatment of lumbar cage pseudoarthrosis: complications.
abstract: METHODS
  A study documenting major complications encountered in revision procedures for lumbar cage pseudoarthrosis.
  
  
  OBJECTIVE
  To document the perioperative complications associated with revision surgery for threaded cylindrical cage pseudoarthrosis.
  
  
  BACKGROUND
  Pseudoarthrosis after cylindrical cage placement manifests as persistent or recurrent pain and disability after surgery. Revision strategies include isolated posterior stabilization and posterior bone grafting, versus circumferential revision where an attempt is made to remove the cages anteriorly, followed by posterior stabilization and fusion. Potential complications associated with these revision procedures have not been adequately documented in the past.
  
  
  METHODS
  Forty-seven consecutive patients with the diagnosis of cylindrical cage pseudoarthrosis were surgically treated with either a circumferential revision (AP) or an isolated posterior instrumented fusion (P). All intraoperative and postoperative complications were documented. Radiographic interbody fusion rates and preoperative and postoperative visual analog scale (VAS) scores were documented.
  
  
  RESULTS
  Three of the AP patients, all with anterior cage placement at L5-S1, had iliac vein lacerations requiring repair. A fourth patient had a ureteral injury requiring subsequent nephrectomy. Three patients who underwent circumferential revision and 2 patients who had an isolated posterior procedure had postoperative complications, including 2 infections (1 AP and 1 P), 1 radiculopathy (P), and 2 patients with prolonged ileus (both AP). There was a statistically significant decrease in overall VAS scores postoperatively for the 2 groups using the paired t test (P<0.0001). There was no difference in either the preoperative (P=0.22) or 2-year postoperative (P=0.30) VAS scores between the AP and P groups [rank-sum (Mann-Whitney) t tests]. Interbody fusion was achieved in 79% (30 of 38 levels) in the AP group. The interbody fusion rate was 37% (8 of 22) for the P group.
  
  
  CONCLUSIONS
  Circumferential revision including cage removal, structural allograft placement, and posterior stabilization is associated with increased perioperative complications. Although an anterior approach showed increased interbody fusion rates, this technique did not lead to more superior clinical outcomes based on VAS scores. It remains to be shown by larger prospective studies if there is a true difference in outcome between these 2 groups that will justify the increased perioperative morbidity associated with attempted cage removal.
authors.affiliation: Department of Orthopaedics, University of Minnesota, Minneapolis, MN, USA. sant0168@umn.edu
authors.forename: Edward R G
authors.initials: ER
authors.lastname: Santos
authors.forename: Manuel R
authors.initials: MR
authors.lastname: Pinto
authors.forename: John E
authors.initials: JE
authors.lastname: Lonstein
authors.forename: Francis
authors.initials: F
authors.lastname: Denis
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Garvey
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Perra
authors.forename: Ensor E
authors.initials: EE
authors.lastname: Transfeldt
authors.forename: James D
authors.initials: JD
authors.lastname: Schwender
mesh_terms: D000328:Adult; D001174:Arthrodesis / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019990:Perioperative Care / Q000009:adverse effects; D011542:Pseudarthrosis / Q000601:surgery*; D012086:Reoperation / Q000009:adverse effects; D013123:Spinal Fusion / Q000009:adverse effects; D016896:Treatment Outcome; D055815:Young Adult