Does the Speed of Sternal Retraction Affect Postoperative Pain Outcomes
Condition: Chronic Pain
MeSH terms: Chronic Pain; Pain, Postoperative
Study type: Interventional

Summary: 
      In North America, almost ½ million people undergo coronary artery bypass graft surgery
      annually and over 1/3rd develop chronic chest pain. The current study will randomize cardiac
      surgery patients to undergo slow sternal retraction for heart exposure (over 15 min.) versus
      standard-of-care (sternal opening over 30 seconds) and examine the incidence and severity of
      chronic post-sternotomy pain (CPSP) and quality-of life 3, 6 and 12 months post-operatively.
      The severity of acute post-operative pain will also be measured. Increased retraction time
      reduces forces required, which should translate to reduced nerve/tissue damage. If effective,
      this simple change in practice could be readily implemented with a major impact for patients
      and the health care system overall.
    

Detailed description: 
      The overall objective of the current investigation is to determine whether increasing the
      time to sternal retraction to 15 minutes (from the standard ~30 sec), will result in reduced
      acute and chronic post-sternotomy pain and an improved quality of life. The hypothesis here
      is that increased time to sternal retraction will result in: reduced required force, less
      physical trauma, less inflammation, and less nerve damage. Specifically, the hypothesis is
      that slow steady sternal retraction (occurring over 15 minutes) will 1) reduce the incidence
      of CPSP by 40% 2) reduce the severity of acute postoperative pain by at least 20-30% and 3)
      significantly improve quality of life 6 months postoperatively.

      The current investigation will be a prospective blinded, randomized, controlled trial.
      Following institutional ethics approval and signed consent, eligible patients scheduled for
      elective coronary artery bypass graft surgery will be randomly assigned (stratified by gender
      and surgeon to ensure equality between groups) either to the Standard group (in which sternal
      retraction occurs over ~30s) or the Slow group in which sternal retraction occurs over 15
      minutes. Patients and research personnel performing the postoperative assessments will remain
      blinded to group assignment until conclusion of the investigation. All other intra-operative
      variables will be performed as per standard practice by the cardiac surgeons at Kingston
      General Hospital. The extent of sternal retraction will be to the surgeon's discretion to
      enable appropriate exposure of the heart to allow safe conduct of the operation but it will
      be recorded in all cases.

      The primary outcome measure will be the incidence of chronic post-sternotomy chest pain 6
      months following CABG with median sternotomy. However, we will also measure the incidence of
      CPSP at 3 and 12 months to determine the trajectory. Secondary outcomes will include: Pain
      intensity (numeric rating scale-NRS) of chest pain (which differs from preoperative) at rest
      and while coughing daily while in hospital until discharge and at 1 week postoperatively.
      Analgesic consumption (morphine equivalents) daily while in hospital until discharge, 1 week
      post-operatively and then at 3, 6, and 12 months postoperatively. Intra-operative data will
      include time from initiation to full retraction, latency from full retraction to sternal
      closure, width of sternal opening at full retraction. Pain quality, quality of life, and pain
      interference with daily function at 3, 6 and 12 months post-operatively. All assessments
      following discharge from the hospital will be via telephone calls from a research nurse
      blinded to randomization assignment. In-hospital assessments will also be done by a research
      nurse blinded to group assignment.
    

Intervention name(s): slow sternal retraction
Intervention type(s): Procedure
Intervention description(s): the sternal retraction (which always need to be performed for coronary artery bypass graft surgery) will be achieved over 15 min instead of the usual 30 sec
Other intervention name(s): slow retraction
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Prevention