Analgesic Consumption in Chronic Marijuana Users Following Orthopedic Trauma Surgery
Condition: Cannabis; Marijuana
MeSH terms: Marijuana Abuse
Study type: Observational

Summary: 
      Marijuana use has increased since its legalization in Canada and many believe that it may
      help patients that are experiencing chronic pain. The investigators want to assess if
      patients who have used marijuana chronically will need more medication to control their pain
      after they have undergone orthopedic trauma surgery (ex. Hip, femur, humerus fractures etc.).
      In this study, the investigators will identify chronic marijuana users (ie. those using for 3
      months or more) who are undergoing orthopedic trauma surgery to assess how much pain
      medication they need post-operatively and compare this with non-users. The investigators will
      also evaluate their pain scores, pain medication use and other complications that they may
      have during or after their surgeries, including any nausea/vomiting, heart or breathing
      problems.
    

Detailed description: 
      Since its legalization in Canada, marijuana consumption has become more common while also
      being the most widely used illicit drug within the USA. In addition to being consumed
      recreationally, cannabis is being increasingly prescribed by medical practitioners as nearly
      15% of Canadian and Australian patients experiencing chronic pain use it as one component of
      treatment. Recent evidence has demonstrated that specific patient cohorts may benefit from
      cannabis, including those with fibromyalgia, diabetic neuropathy, complex regional pain
      syndrome, multiple sclerosis, traumatic neuropathic pain, and difficulty sleeping due to
      chronic pain, amongst others. Cannabis contains two main components:
      delta-9-tetrahydrocannabinol (THC), which is active, and cannabidiol, which is inactive. THC
      has its effects by binding to Type 1 cannabinoid receptors and inhibiting pain pathways while
      activation of Type 2 cannabinoid receptors have anti-inflammatory properties.

      As literature continues to investigate its analgesic characteristics, many proponents of
      cannabis use believe that it can modify pain response in various settings. One such setting
      that is of special interest for pain control is during the post-operative period. Currently,
      there is minimal data available to reflect the analgesic requirement, and thus degree of
      pain, for a patient who is a chronic marijuana user immediately following a surgical
      procedure. A class of surgical procedures that is of particular interest to us due to its
      pain-evoking characteristics is orthopedic trauma surgery. In fact, orthopedic surgeons are
      one of the higher opioid prescribing specialists, potentially highlighting the difficulty in
      achieving adequate pain control in their patient population. More information is required to
      better tailor analgesia for these patients as it may contribute towards their overall
      recovery, restoring mobility, and patient satisfaction (6,7).

      Through this study, the investigators would like to investigate the relationship between
      orthopedic trauma surgery and post-operative pain control in the chronic marijuana user.
      Minimal data is available in the literature reflecting this potentially common situation.
      Specifically, the investigators are interested in the clinical implications of marijuana use
      on opioid consumption and verbal pain rating in this patient scenario. The investigators also
      hope that the data can reflect possible side effects or other concerning outcomes in the
      peri-operative period so that clinicians may be able to provide more personalized care to
      these patients.
    

Observational model: Case-Control
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        Patient recruits will be identified by accessing the electronic health record at the
        University of Alberta hospital (Edmonton, Alberta, Canada) and the written slate available
        at the Royal Alexandra hospital (Edmonton, Alberta, Canada). These sources will list the
        elective orthopedic slate, accessible about 1 week prior to surgery, and the trauma slate
        which is available at least 24 hours prior to surgery. Patients can also be identified in
        the pre-assessment clinic. Research supervisors and designated assistants will be
        responsible for identifying potential participants. Once their location is identified, the
        research assistant will consent the patient at least 12 hours prior to surgery or in the
        pre-assessment clinic where patients will attend at least 24 hours prior to surgery.