In Response

Abstract

We thank Dr. Altman and his colleagues for their comments on our quantitative review of the benefits of interscalene block for shoulder surgery.1 The authors raise important points relating to our rationale for pooling data as well as the use of perineural adjuncts in clinical practice. We maintain that the surgical populations, interventions, and comparators included in our review were sufficiently homogenous to warrant pooling. In addition, we duly performed subgroup analysis to examine differences (eg, open versus closed surgery, short-acting versus long-acting local anesthetics, nerve stimulator guidance versus ultrasound guidance) that may have influenced our findings. Importantly, these differences do not preclude pooling, and modern regional anesthesia literature includes numerous examples of landmark meta-analyses2–5 that pooled trials with such differences. It is most important to recognize, acknowledge, and account for these differences, and we believe that we have done so satisfactorily. The effect of perineural local anesthetic adjuncts, such as dexamethasone, on the duration of analgesia associated with interscalene block is an evolving subject of substantial promise. Indeed, although many practitioners consider the addition of dexamethasone to the local anesthetic solution routine, questions regarding its minimal effective dose, route of administration (perineural versus intravenous), and safety persist. As such, studies investigating the use of perineural adjuncts or encapsulated local anesthetics were excluded from our analyses. The latter notwithstanding, our results definitively indicate that interscalene block via the use of local anesthetic alone provides dynamic and rest pain up to 6 and 8 hours, respectively. Interscalene block also provides an opioid-sparing effect and reduces opioid-related side effects up to 12 and 24 hours, respectively. Indeed, single-injection interscalene block with local anesthetic alone remains the care standard for ambulatory shoulder surgery at our home institution. Faraj W. Abdallah, MDDepartment of AnesthesiaUniversity of TorontoToronto, Ontario, CanadaDepartment of AnesthesiaKeenan Research CentreLi Ka Shing Knowledge InstituteSt. Michael’s HospitalToronto, Ontario, Canada Richard Brull, MD, FRCPCDepartment of AnesthesiaUniversity of TorontoToronto, Ontario, CanadaDepartment of AnesthesiaWomen’s College HospitalToronto, Ontario, Canada[email protected]