Bilateral Continuous Erector Spinae Blocks for Post-Sternotomy Pain Management: A Pilot Study
Condition: Pain, Postoperative
MeSH terms: Pain, Postoperative
Study type: Interventional
Phase: Phase 3

Summary: 
      Overall Aim: To evaluate the feasibility and potential benefits of investigating bilateral
      continuous erector spinae blocks (BESB) for postoperative pain management in a small cohort
      of children undergoing surgical sternotomy prior to planning an appropriately powered,
      randomized, controlled trial of the same.

      Hypothesis: The investigators' primary hypothesis is that utilizing bilateral erector spinae
      blocks for post-sternotomy pain is a feasible intervention for consideration in a larger
      trial by demonstrating a 75% or greater successful intervention completion rate without any
      major adverse outcomes.
    

Detailed description: 
      Regional anesthesia-and pediatric regional anesthesia in particular-is a rapidly evolving
      subfield of anesthesia practice driven with considerable urgency by the growing recognition
      that even appropriate perioperative narcotic administration can have significant derogatory
      long-term effects.

      Regional anesthetics can provide targeted, continuous analgesia to select dermatomes with
      minimal additional patient risk and as such have become routine components of opioid-sparing
      intraoperative and postoperative pain management plans for surgical patients at BCH. In
      addition to the postulated benefit of reducing overall opioid exposure and potentially
      reducing the risk for long term physiologic and behavioral dependence upon opioids, regional
      anesthetics may allow for earlier extubation after selected surgeries, shorter ICU, PACU and
      inpatient admissions, earlier mobilization, fewer gastrointestinal complications, and
      improved patient satisfaction scores.

      Despite a robust literature supporting the safety and efficacy of regional anesthesia for
      postoperative pain control across a broad range or surgery types, patient demographics and
      underlying comorbidities, there are certain classes of surgeries that have (to date) not
      benefitted from the advantages that regional anesthetics may provide, most notably spine
      surgery and cardiac surgery.

      Concerns have been expressed with regard to regional anesthetics for cardiac surgeries in
      particular (this being the primary surgical type associated with sternotomies in a pediatric
      populations), given that most patients are pharmacologically anticoagulated to some extent
      during their procedures and are thus at increased risk for bleeding. This is further
      complicated in the pediatric cardiac surgical population as many of these children are
      intubated for an extended period of time and therefore may not have particularly reliable
      neurological exams in the setting of neuraxial regional anesthetics-potentially resulting in
      unrecognized acquired neurological defecits. While there is emerging evidence of improved
      outcomes with neuraxial regional anesthetics in adult cardiac surgery patients, this has not
      trickled down to the pediatric population, likely for some of these reasons.

      The investigators at BCH are fortunate to have one of the largest concentrated pediatric
      cardiac surgical populations in the US along with an active, and well organized regional
      anesthesia service. Because of this, the investigators are in a unique position to more
      thoroughly evaluate the effectiveness and safety of regional anesthetics in children
      following cardiac surgery. Furthermore it is thought to be critical that institutions such as
      BCH take a leading role in documenting the effects of regional anesthesia on the most
      important outcome measures when considering perioperative medicine. These include: overall
      pain management, surgical healing, functional recovery, long term pain symptoms, and
      emotional/behavioral outcomes after surgery.

      Recently, the erector spinae block (ESB) has become popular for providing analgesia after a
      number of anterior chest and abdominal procedures. This is a simple interfascial plane block
      that can reliably provide unilateral chest and/or abdominal wall analgesia. It has been
      described in numerous case reports and one case series as an effective block for management
      of unilateral thoracotomies, unilateral rib fractures, unilateral abdominal incisions and
      most notably, when used bilaterally, for management of post-sternotomy pain. New case reports
      and series involving the ESB are being published almost weekly at this point with a growing
      literature specific to cardiac surgical applications. Indeed a randomized controlled trial to
      investigate the analgesic efficacy of bilateral erector spinae plane (BESP) blocks compared
      with conventional treatment for pain after cardiac surgery in adult patients was published
      recently (2018) with promising results.

      As an interfascial plane block in a compressible anatomical space, the ESB is thought to be
      safe in anticoagulated (or recently anticoagulated) patients. It is fast becoming a preferred
      anesthetic option for these pharmacologically or otherwise coagulopathic patients as opposed
      to neuraxial (e.g. epidural) and paraneuraxial blocks (i.e. paravertebral) nerve blocks,
      which are largely contraindicated in this setting.

      Given the ESB's potentially favorable risk profile versus the other blocks that would
      subserve the same dermatomes (i.e. it is technically less challenging, more distant from
      critical structures, and thought to be safe in anticoagulated patients) it could provide both
      a safer and easier to perform regional anesthesia option for many patients. In particular, it
      offers a new option for a subset of anticoagulated patients for whom other regional
      techniques (epidural, paravertebral) are contraindicated. This is particularly true for the
      populations of pediatric cardiac surgical patients at BCH if used bilaterally.

      Indeed, given the current information available related to the ESB, the regional anesthesia
      service at BCH has begun employing it when possible in circumstances when a neuraxial or
      paravertebral block(s) would commonly be used but is/are relatively or absolutely
      contraindicated. Patients undergoing thoracotomies while anticoagulated for cardiopulmonary
      bypass, aortic clamping, etc. have been successfully managed with unilateral continuous ESBs.
      In addition, thoracotomies in patients with acquired (e.g. dilutional) and other pathologic
      coagulopathies have been managed with ESBs. As such, the ESB has been adopted for routine use
      in specific patient populations at BCH and has even occasionally been utilized in lieu of the
      more longstanding routine PVBs or epidural blocks for patients without contraindication for
      such.

      Retrospective review of BCH outcomes data for 67 ESBs done for a variety of surgeries and
      populations has not revealed any significant differences between PVBs and ESBs in terms of
      adverse events, postoperative opiate use, median pain scores, or other standard outcomes
      measures. As this data is observational in nature, it is difficult to draw firm conclusions
      as to the efficacy of the two blocks. However, since there are distinct known and described
      advantages associated with regional anesthetics for postoperative pain management, it would
      be prudent to evaluate these blocks in a controlled, randomized, trial. Prior to such a
      trial, a pilot study to evaluate the feasibility of such a trial is warranted.

      As such, the investigators propose to evaluate the feasibility of investigating bilateral
      continuous erector spinae blocks (BESB) for patients undergoing surgical sternotomy by means
      of a pilot study. For this study, 'feasibility' will be defined primarily as a successful
      intervention completion rate of 75% or greater of all subjects with no major adverse
      outcomes. Secondary measures of feasibility will include aggregate 'data integrity' as
      defined by successful collection of 75% or greater of all possible data points for
      successfully completed subjects as well as 'efficient intervention duration' as evaluated by
      intervention completion time being less than 40 minutes.
    

Intervention name(s): Ropivacaine
Intervention type(s): Drug
Intervention description(s): Erector spinae blocks: T4/5 transverse process is identified with the ultrasound transducer in a parasagittal orientation; the needle tip is advanced until it contacts the transverse process, just below the erector spinae muscle complex; the erector spinae muscle is visualized to be elevated up off of the transverse process with normal saline injection. Following a bolus injection of 2ml/kg of 0.2% ropivacaine, a catheter is threaded into the space occupied by the local anesthetic bolus. Repeated on contralateral side.
Other intervention name(s): Naropin
Intervention MeSH terms: Ropivacaine
Intervention model: Single Group Assignment
Intervention model description: Single intervention group, bilateral erector spinae blocks with 0.2% ropivacaine, to assess the feasibility of this technique for postoperative pain control following surgeries involving sternotomies in children.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: erector spinae block; regional anesthesia; sternotomy; ropivacaine