title: Transversus abdominis plane block in robotic gynecologic oncology: a randomized, placebo-controlled trial.
abstract: OBJECTIVE
  Although robotic surgery decreases pain compared to laparotomy, postoperative pain can be a concern near the site of a larger assistant trocar site. The aim of this study was to determine the efficacy of transversus abdominis plane (TAP) block on 24-hour postoperative opiate use after robotic surgery for gynecologic cancer.
  
  
  METHODS
  Sixty-four subjects with gynecologic malignancies who were scheduled to undergo robotic surgery were enrolled into the study. They were randomized to receive a unilateral TAP block to the side of the assistant port via ultrasound guidance. The block was comprised of 30 cc of 0.25% bupivacaine with 3 mcg/mL epinephrine or saline. Opiate use was measured and converted into IV morphine equivalents. Patient-reported pain was measured using the Brief Pain Inventory (BPI) and Visual Analog Scale (VAS).
  
  
  RESULTS
  The treatment group used a mean of 64.9 mg morphine in the first 24h compared to 69.3mg for controls (primary outcome, p=0.52). After age-adjustment, the treatment group used a mean of 11.1mg morphine less than controls (p=0.09). Postoperative pain scores assessed by the BPI (6.44 vs. 6.97, p=0.37) and the VAS (3.12 vs. 3.61, p=0.30) were equivalent. Block placement was uncomplicated in 98.4% of participants with mean BMI of 35.3 kg/m(2). Linear regression revealed an approximate 8.1mg decrease in morphine equivalents used per additional decade of life (p=0.0008). There was a positive correlation between the amount of opiates and BMI with an additional 8.8 mg of morphine per 10 kg/m(2) increase in BMI (p=0.0012).
  
  
  CONCLUSIONS
  TAP block is safe and feasible in this patient population with a large proportion of morbid obesity. Preoperative TAP block does not significantly decrease opiate use. However; based on these data, a clinically useful nomogram has been created to aid clinicians in postoperative opiate-dosing for patients based on age and BMI.
authors.affiliation: Department of Obstetrics and Gynecology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: B T
authors.initials: BT
authors.lastname: Hotujec
authors.affiliation: Division of Gynecologic Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Spencer
authors.affiliation: Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Donnelly
authors.affiliation: Department of Anesthesiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Bruggink
authors.affiliation: Division of Gynecologic Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Rose
authors.affiliation: Division of Gynecologic Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: A
authors.initials: A
authors.lastname: Al-Niaimi
authors.affiliation: Department of Biostatistics and Medical Informatics, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: R
authors.initials: R
authors.lastname: Chappell
authors.affiliation: Division of Gynecologic Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Stewart
authors.affiliation: Division of Gynecologic Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53792, USA. Electronic address: dmkushner@wisc.edu.
authors.forename: D M
authors.initials: DM
authors.lastname: Kushner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000701:Analgesics, Opioid / Q000627:therapeutic use; D000779:Anesthetics, Local / Q000627:therapeutic use*; D002045:Bupivacaine / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005500:Follow-Up Studies; D005833:Genital Neoplasms, Female / Q000601:surgery*; D006801:Humans; D010535:Laparoscopy; D016014:Linear Models; D008875:Middle Aged; D009020:Morphine / Q000627:therapeutic use; D009407:Nerve Block / Q000379:methods*; D049451:Nomograms; D010147:Pain Measurement; D010149:Postoperative Pain / Q000188:drug therapy / Q000517:prevention & control*; D012371:Robotics; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D000779:Anesthetics, Local; D009020:Morphine; D002045:Bupivacaine
keywords: Postoperative analgesia; Robotic surgery; Transversus abdominis plane block