title: Efficacy of augmenting a subacromial continuous-infusion pump with a preoperative interscalene block in outpatient arthroscopic shoulder surgery: a prospective, randomized, blinded, and placebo-controlled study.
abstract: OBJECTIVE
  This study's purpose was to determine the effectiveness of adding a preoperative interscalene brachial plexus block to standard postoperative management, including oral narcotics and a subacromial bupivacaine infusion pump, after arthroscopic shoulder surgery.
  
  
  METHODS
  After performing a prospective power analysis and obtaining institutional board approval, we conducted a randomized placebo-controlled trial of 53 patients separated into a preoperative interscalene brachial plexus group and a control group. Group 1 received an interscalene block with 30 mL of 0.5% ropivacaine. Group 2 received a placebo with 10 mL of saline solution. All patients postoperatively received an arthroscopically placed subacromial infusion pump catheter for 72 hours and oral narcotics. Pain scores on a visual analog scale (VAS) and narcotic pill use were recorded at 6, 12, 20, 32, 40, 52, 60, 72, and 80 hours.
  
  
  RESULTS
  Preoperative pain scores between groups were not significant (P > .05). A statistically significant difference was found for decreased pain scores at 6 hours after discharge in patients receiving an interscalene block (P = .001) (VAS of 30.9 in group 1 v 61.8 in group 2). There was also a decrease in the number of narcotic pills taken at the 6-hour time interval (P = .1) (0.6 pills v 1.1 pills). Group 1 had a rebound phenomenon 20 hours after discharge. Pain scores spiked as the effects of the block wore off (P = .08) (net change in VAS score increase, 25.0 v 10.3). No other statistical or clinical differences were observed.
  
  
  CONCLUSIONS
  The addition of a preoperative interscalene block to a postoperative subacromial infusion pump provided significant improvement of pain control only at 6 hours after discharge. Twelve hours after discharge, this benefit had disappeared. A rebound phenomenon of increased pain at 20 hours was seen after the interscalene block had worn off. After 20 hours, no statistically significant or clinically applicable differences were found.
  
  
  METHODS
  Level I, randomized controlled trial.
authors.affiliation: Palmetto Orthopaedics of Charleston, Mount Pleasant, South Carolina 29464, USA. demarcoj@musc.edu
authors.forename: James R
authors.initials: JR
authors.lastname: DeMarco
authors.forename: Roger
authors.initials: R
authors.lastname: Componovo
authors.forename: William R
authors.initials: WR
authors.lastname: Barfield
authors.forename: Laura
authors.initials: L
authors.lastname: Liles
authors.forename: Paul
authors.initials: P
authors.lastname: Nietert
mesh_terms: D000082:Acetaminophen / Q000627:therapeutic use; D000284:Administration, Oral; D000328:Adult; D000577:Amides / Q000008:administration & dosage / Q000627:therapeutic use*; D000700:Analgesics / Q000627:therapeutic use; D000779:Anesthetics, Local / Q000008:administration & dosage*; D001182:Arthroscopy / Q000379:methods*; D001917:Brachial Plexus; D002045:Bupivacaine / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D006801:Humans; D015918:Infusion Pumps, Implantable; D007267:Injections; D009407:Nerve Block / Q000295:instrumentation* / Q000379:methods; D010098:Oxycodone / Q000627:therapeutic use; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control*; D011182:Postoperative Care / Q000379:methods; D011300:Preoperative Care / Q000379:methods*; D011446:Prospective Studies; D000077212:Ropivacaine; D012785:Shoulder Joint / Q000601:surgery*; D020069:Shoulder Pain / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control*; D013997:Time Factors
chemical_list: D000577:Amides; D000700:Analgesics; D000779:Anesthetics, Local; D000082:Acetaminophen; D000077212:Ropivacaine; D010098:Oxycodone; D002045:Bupivacaine