The boom of peripheral nerve blocks during the last years was supported by the hope that patients’ outcomes would be greatly improved, and has led to the introduction of a number of new approaches. However, for many of these blocks, robust data demonstrating real patient benefits are still inconsistent.
Until now, single-shot regional anesthesia has been shown not to have medium-term or long-term benefits.1–3 In a systematic review and meta-analysis in this issue of Anesthesia & Analgesia, Abdallah et al.4 challenged the question of whether single-shot interscalene block improved short-term outcomes. Despite the methodologic limitations of a systematic review and meta-analysis, this work has sufficient evidence to conclude that a single-shot interscalene block provided better pain control only up to 6 hours with motion and 8 hours at rest after various shoulder surgeries. Minor outcomes such as an opioid-sparing effect, reduced opioid side effects, and patient satisfaction were present but limited to the first 24 postoperative hours. These results raised the question whether it is still worthwhile to perform single-shot interscalene block in this context, knowing that interscalene block may be associated, although rarely, with serious complications.5,6 For minor shoulder procedures to avoid general anesthesia in specific indications, single-shot interscalene block is still undoubtedly a good option. The real question is what to do with major shoulder procedures, such as rotator cuff repair or shoulder arthroplasty, which are very painful and require the possibility to perform early passive mobilization in the modern orthopedic world. In this setting, a single-shot interscalene block will neither significantly reduce opioid consumption nor allow early mobilization and therefore its use considering the risk/benefit ratio is questionable. To make this issue more complicated, blockade of delta fibers, necessary to allow early mobilization, is poorly achieved with opioids.7
This investigation also highlighted the occurrence of a new problem, that of rebound pain.8 Rebound pain increasingly is recognized by anesthesiologists involved in the practice of peripheral nerve blocks. For the patient, it is very painful when the block wears off. Large amounts of opioids are necessary to provide adequate pain control, blunting one of the primary goals of regional anesthesia, which is avoidance or reduction of opioids. How should we cope with this issue? The most useful and logical technique is the use of a perineural interscalene catheter, which allows a soft transition from high to low local anesthetic concentration. A gradual decrease has been shown to be beneficial. This decrease is supported by an investigation after rotator cuff repair in which the authors demonstrated that the administration of ropivacaine 0.3% for the first 24 hours and then 0.2% for the following 24 hours was shown to provide the most benefits to the patient.9
The work of Abdallah et al.4 highlights some important messages. The hope that perineural blocks greatly improved patients’ medium-term and long-term outcomes is still unclear. Unfortunately, data showing definitive and undisputable long-term benefits are not available. The enthusiasm for single-shot perineural block should be tempered, and the current need to assess the risk/benefit of each block seems reasonable. Perineural block has reached adulthood and for anesthesiologists performing regional techniques the time to think “when to block, when not to block, and how to block” has come.
Name: Alain Borgeat, MD.
Contribution: This author wrote the manuscript.
Attestation: Alain Borgeat attests to the integrity of the original data and the analysis reported in this manuscript.
This manuscript was handled by: Spencer S. Liu, MD.
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