The Effects of Dexamethasone on Low Dose Interscalene Brachial Plexus Block
Condition: Shoulder Surgery; Nerve Block
Study type: Interventional
Phase: Phase 4

Summary: 
      A standard interscalene nerve block is performed with long acting local anesthetic
      (bupivacaine or ropivacaine in concentrations varying from 0.25% to 0.75%). The purpose of
      this study is to investigate the effect of the addition of perineural dexamethasone (4mg) to
      a standard ropivacaine solution (0.5%) on analgesic duration of low dose interscalene block
      compared to ropivacaine alone for interscalene block with systemic dexamethasone.

      Ropivacaine is not an intervention as a local anesthetic is pre-requisite to performing a
      nerve block.
    

Detailed description: 
      Interscalene brachial plexus block (ISB) is regarded as the standard of care for analgesia
      after shoulder surgery providing superior analgesia and reducing opioid consumption. Shoulder
      surgery, previously requiring inpatient admission for pain control, is now commonly performed
      on an ambulatory basis facilitated by ISB analgesia. The effects of single injection ISB
      dissipate after several hours unmasking the moderate to severe pain of the surgical insult
      and require strong opioid analgesia. Efforts to prolong ISB duration by increasing local
      anaesthetic (LA) dose are limited by their pharmacodynamics and narrow therapeutic window. To
      address some of these issues faced with prolonging ISB analgesia the addition of perineural
      adjuvants to local anesthetic (eg. clonidine, dexmedetomidine), have been investigated in an
      attempt to prolong peripheral nerve block duration with limited success. However, the
      corticosteroid dexamethasone, has been added to local anesthetic solutions for ISB and has
      demonstrated promise in preliminary studies. Perineural dexamethasone (8-10mg) in conjunction
      with local anesthetic prolongs the duration of ISB with an effect sizes ranging from 40% to
      75% (absolute effect ~ 6 to 10 hours). Dexamethasone, however, is only approved for
      intramuscular or intravenous administration and therefore perineural use is currently
      off-label. There are several reasons that warrant a new randomized trial. Chiefly, all of the
      previous trials do not reflect modern regional anesthetic practice. These trials utilized
      peripheral nerve stimulation (PNS) and local anesthetic volumes of 30 to 40 ml. Modern
      ultrasound guided ISB (US-ISB) allows for more accurate, targeted deposition of local
      anesthetic with volumes ranging from 5 to 10 ml with no difference in block efficacy or
      duration compared to larger volumes (≥20ml). An ideal solution would be a local anesthetic
      with adjuvant mixture that allowed administration of lower volumes but with prolonged
      analgesic duration. The use of low dose local anesthetic with dexamethasone could be one such
      solution. A trial that demonstrates enhanced block quality and duration associated with
      perineural dexamethasone added to low dose local anesthetic may allow us to achieve both
      prolonged duration of effect and reduced side effects due to unwanted local anesthetic
      spread. This would create further significant benefits for patients and further promote the
      use of low dose local anesthetic techniques to anesthesiologists who do not currently use
      this technique.
    

Intervention name(s): Systemic Dexamethasone; Perineural dexamethasone
Intervention type(s): Drug; Drug
Intervention description(s): Intravenous infusion of dexamethasone (4mg); Perinerual administration of dexamethasone (4mg)
Other intervention name(s): Dexamethasone Sodium Phosphate Injection; Dexamethasone Sodium Phosphate Injection
Intervention MeSH terms: Dexamethasone; Dexamethasone acetate; Dexamethasone 21-phosphate; BB 1101
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment