title: Systematic review and meta-analysis of randomized clinical trials of self-expanding metallic stents as a bridge to surgery versus emergency surgery for malignant left-sided large bowel obstruction.
abstract: BACKGROUND
  Use of self-expanding metallic stents (SEMS) as a bridge to surgery has been suggested as an alternative management for acute malignant left-sided colonic obstruction, as emergency surgery has a high risk of morbidity and mortality. This meta-analysis evaluated high-quality evidence comparing preoperative SEMS with emergency surgery.
  
  
  METHODS
  Relevant randomized clinical trials (RCTs) were identified from the Cochrane Central Register of Controlled Trials, MEDLINE, Embase and PubMed (1990-2011). Primary outcomes were primary anastomosis, stoma and in-hospital mortality rates. Secondary outcomes included anastomotic leak, 30-day reoperation and surgical-site infection rates.
  
  
  RESULTS
  Four RCTs with 234 patients were included. Technical and clinical success rates for stenting were 70·7 per cent (82 of 116) and 69·0 per cent (80 of 116) respectively. The clinical perforation rate was 6·9 per cent (8 of 116) and the silent perforation rate 14 per cent (11 of 77). SEMS intervention resulted in significantly higher successful primary anastomosis (risk ratio (RR) 1·58, 95 per cent confidence interval 1·22 to 2·04; P < 0·001) and lower overall stoma (RR 0·71, 0·56 to 0·89; P = 0·004) rates. There was no difference in primary anastomosis, permanent stoma, in-hospital mortality, anastomotic leak, 30-day reoperation and surgical-site infection rates. Three trials were stopped prematurely, one because the emergency surgery group had a significantly increased anastomotic leak rate, and two others because of stent-related complications and increased 30-day morbidity following SEMS management.
  
  
  CONCLUSIONS
  Technical and clinical success rates for stenting were lower than expected. SEMS is associated with a high incidence of clinical and silent perforation. However, as a bridge to surgery, SEMS has higher successful primary anastomosis and lower overall stoma rates, with no significant difference in complications or mortality.
authors.affiliation: Colorectal Unit, Royal Victoria Hospital, 274 Grosvenor Road, Belfast BT12 6BA, UK. cjtan99@hotmail.com
authors.forename: C J
authors.initials: CJ
authors.lastname: Tan
authors.forename: B V M
authors.initials: BV
authors.lastname: Dasari
authors.forename: K
authors.initials: K
authors.lastname: Gardiner
mesh_terms: D000714:Anastomosis, Surgical; D057868:Anastomotic Leak / Q000209:etiology; D015982:Bias; D003108:Colonic Diseases / Q000601:surgery*; D003125:Colostomy / Q000706:statistics & numerical data; D004638:Emergency Treatment / Q000379:methods; D017052:Hospital Mortality; D006801:Humans; D007415:Intestinal Obstruction / Q000601:surgery*; D016032:Randomized Controlled Trials as Topic; D012086:Reoperation / Q000706:statistics & numerical data; D015607:Stents; D013530:Surgical Wound Infection / Q000209:etiology; D016896:Treatment Outcome