Continuous Erector Spinae Block Versus Continuous Paravertebral Block

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 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.

Given the rapid evolution of the field of regional anesthesia and the fact that there are
often multiple approaches for achieving analgesia in a select set of dermatomes, there are
often a variety of regional anesthetic options for any given surgery. Some approaches are
longstanding and well-studied, but with increasing frequency since the advent of ultrasound
guidance, newer, novel nerve block options exist. As it is often expensive and work-intensive
to thoroughly evaluate a given regional technique with a controlled pediatric trial, many of
these blocks become standards of practice based on anecdote, retrospective analysis, or
simply belief in the putative benefits of regional anesthetics.

The investigators are fortunate at BCH to have one of the largest concentrated pediatric
surgical populations in the US. They also have 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 anesthesia in children.
Furthermore, the investigators feel it is 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 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 (when used bilaterally) for
management of post-sternotomy pain.

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 patients as opposed to neuraxial (e.g. epidural) and
paraneuraxial (i.e. paravertebral) nerve blocks.

Given the ESB's potentially favorable risk profile versus the other blocks (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. It also offers a new option for a subset of
anticoagulated patients for whom other regional techniques (epidural, paravertebral) are
contraindicated.

Indeed, given the current information available related to the ESB, the regional anesthesia
service at BCH has begun employing it when possible in circumstances where a PVB would
commonly be used but is relatively or absolutely contraindicated. Patients undergoing
thoracotomies while anticoagulated for cardiopulmonary bypass, aortic clamping, etc. have
been successfully managed with 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 47 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 comparative efficacy of the two blocks. However, since there are differences in
technical difficulty, relative contraindications, and there exist populations that might
benefit from these blocks, it would be prudent to comparatively evaluate these blocks in a
controlled, randomized, trial.

The investigators propose to evaluate the comparative efficacy of ESBs and PVBs for patients
undergoing unilateral non-cardiac thoracotomy by means of a randomized, controlled
non-inferiority study (based on a threshold of clinical significance being defined as a 15%
difference) comparing rescue analgesic requirements, rendered as opiate equivalents, at 24
postoperatively. Rescue opiates will be available as needed by means of standard PCA/NCA
demand protocols. Secondary measures will include rescue opiate requirements at 48 and 72
hours, pain scores, adverse events, time to discharge from the ICU, time to extubation,
patient disposition after surgery, and time to perform the block in the operating room.

Inclusion Criteria:

- ASA I - III status, undergoing unilateral thoracotomy for either esophageal atresia
related intrathoracic procedures or other non-cardiac general surgical intrathoracic
procedures.

Exclusion Criteria:

- Patients undergoing procedures including pleurodesis, pleural stripping, and
decortication or other procedures with widely distributed pleural disruption.

- Patients with severe neurodevelopmental delays.

- Patients with previous chronic pain syndromes.

- Patients with a history of opioid treatment at any point in the 2 months prior to
surgery.

- Lack of parental consent and/or child assent.