Analgesic Benefit of PECS Blocks for Biceps Tenodesis Shoulder Surgery

Subjects that meet the inclusion criteria will be assigned a group by using a random numbers generator. All subjects will receive the standard practice at our institution of an interscalene brachial plexus block along with a general anesthetic. The intervention arm will get an additional local anesthetic block targeting nerves that we presume cover the axillary region (PECS "Pectoralis" 1 & 2). These nerves in the upper chest are the lateral branches of the 2nd to 5th intercostal nerves, which includes the intercostobrachial nerve. The anesthesiologist placing the nerve blocks will be un-blinded to perform the procedures. Both the surgeon and the Acute Pain Service anesthesiologist will be blinded as to whether or not the intervention was provided to any given subject. The Acute Pain Service team will remain blinded and collect the data outcomes.

Initially, pilot data was collected in a total of ten patients with five patients randomized to each arm. Primary endpoint was NRS "Numerical Rating Scale" of 0-10 at 6hrs after block placement. Our pilot data indicate that the mean NRS is about 5 for the control group, with a standard deviation of 1.4. Using a two-sided two-sample t test (an alpha of 0.05 and power of 0.95), we conservatively estimate that 14 subjects per arm will be needed to detect a clinically meaningful difference of 2 in NRS between the arms. We decided to plan enrollment of 20 subjects per arm for potential loss during this randomized, double-blinded, single-center, sham block trial.

• Potential subjects undergoing arthroscopy will have their electronic medical record reviewed by the study team to look for exclusion criteria. If the subject is excluded, then they will be added to the Screening Log with date and reason for their exclusion. If all inclusion criteria are met, then the subject will be approached in the Regional Anesthesia area for their consent. A copy of the consent will be given to the study subject. The other informed consent document will be maintained by the study team in the research files.
• Patients will be asked to provide baseline pain scores both, at rest and with movement, on a scale of 0-10 (0 being no pain and 10 being the worst pain). Preoperative opioid use including drug(s), dosage and frequency will be recorded. Randomization of patients will then occur through the use of sequentially numbered envelopes with only those directly involved in the care of the patient during block placement being aware of which arm of the study the patient has been randomized. Those members of the study team who will be collecting post-operative data will be blinded to the randomization.

Standard American Society of Anesthesiology monitors and oxygen will be applied. Unless there is a contraindication, each patient will receive 650mg "milligrams" of oral acetaminophen. To standardize the effect on postoperative pain, ketamine will not be given as a preoperative sedation medication or intraoperative medication. No long acting opioids will be given in the operating room or post-anesthesia care unit. Intraoperative fentanyl will be limited to 5 micrograms per kg "kilogram". Intraoperative dexamethasone will not be given for post-operative nausea/vomiting prophylaxis.

Subjects will be sedated as per usual practice and will also be blinded to their randomization. All peripheral nerve blocks will be performed by a resident or fellow under supervision by an attending anesthesiologist. The attending anesthesiologist may perform the procedures alone. All volumes and concentrations of nerve block mixtures administered will be identical to assist in the blinding process.