title: Reducing persistent postoperative pain and disability 1 year after breast cancer surgery: a randomized, controlled trial comparing thoracic paravertebral block to local anesthetic infiltration.
abstract: BACKGROUND
  The objective of this study was to compare the effect of thoracic paravertebral block (TPVB) and local anesthetic (LA) on persistent postoperative pain (PPP) 1 year following breast cancer surgery. Secondary objectives were to compare the effect on arm morbidity and quality of life.
  
  
  METHODS
  Women scheduled for elective breast cancer surgery were randomly assigned to either TPVB or LA followed by general anesthesia. An NRS value of >3 at rest or with movement 1 year following surgery defined PPP. Blinded interim analysis suggested rates of PPP much lower than anticipated, making detection of the specified 20 % absolute reduction in the primary outcome impossible. Recruitment was stopped, and all enrolled patients were followed to 1 year.
  
  
  RESULTS
  A total of 145 participants were recruited; 65 were randomized to TPVB and 64 to LA. Groups were similar with respect to demographic and treatment characteristics. Only 9 patients (8 %; 95 % CI 4-14 %) met criteria for PPP 1 year following surgery; 5 were in the TPVB and 4 in the LA group. Brief Pain Inventory severity and interference scores were low in both groups. Arm morbidity and quality of life were similar in both groups. The 9 patients with PPP reported shoulder-arm morbidity and reduced quality of life.
  
  
  CONCLUSIONS
  This study reports a low incidence of chronic pain 1 year following major breast cancer surgery. Although PPP was uncommon at 1 year, it had a large impact on the affected patients' arm morbidity and quality of life.
authors.affiliation: Department of Anesthesiology, University of Ottawa, Ottawa, ON, Canada, mchiu@toh.on.ca.
authors.forename: Michelle
authors.initials: M
authors.lastname: Chiu
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Bryson
authors.forename: Anne
authors.initials: A
authors.lastname: Lui
authors.forename: James M
authors.initials: JM
authors.lastname: Watters
authors.forename: Monica
authors.initials: M
authors.lastname: Taljaard
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Nathan
mesh_terms: D000779:Anesthetics, Local / Q000008:administration & dosage*; D001943:Breast Neoplasms / Q000473:pathology / Q000534:rehabilitation* / Q000601:surgery*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008408:Mastectomy; D008875:Middle Aged; D009367:Neoplasm Staging; D009407:Nerve Block / Q000379:methods*; D010147:Pain Measurement; D010149:Postoperative Pain / Q000517:prevention & control*; D011379:Prognosis; D013904:Thoracic Vertebrae / Q000601:surgery*
chemical_list: D000779:Anesthetics, Local