Regional anesthesia and pain medicine
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Reg Anesth Pain Med · Feb 2025
ReviewMachine learning research methods to predict postoperative pain and opioid use: a narrative review.
The use of machine learning to predict postoperative pain and opioid use has likely been catalyzed by the availability of complex patient-level data, computational and statistical advancements, the prevalence and impact of chronic postsurgical pain, and the persistence of the opioid crisis. The objectives of this narrative review were to identify and characterize methodological aspects of studies that have developed and/or tested machine learning algorithms to predict acute, subacute, or chronic pain or opioid use after any surgery and to propose considerations for future machine learning studies. Pairs of independent reviewers screened titles and abstracts of 280 PubMed-indexed articles and ultimately extracted data from 61 studies that met entry criteria. ⋯ We identified variability in sample size, number and type of predictors, and how outcome variables were defined. Patient-reported predictors were highlighted as particularly informative and important to include in such machine learning algorithms, where possible. We hope that findings from this review might inform future applications of machine learning that improve the performance and clinical utility of resultant machine learning algorithms.
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Reg Anesth Pain Med · Feb 2025
ReviewN-Methyl-D-aspartate receptor antagonists for the prevention of chronic postsurgical pain: a narrative review.
The N-methyl-D-aspartate receptor (NMDAR) has been linked to the development of chronic postsurgical pain (CPSP), defined as pain after surgery that does not resolve by 3 months. Once the combination of a painful stimulus and glutamate binding activates the NMDAR, calcium influx triggers signaling cascades that lead to processes like central sensitization and CPSP. Three of the most widely studied perioperative NMDAR antagonists include ketamine, magnesium, and methadone, with ketamine having garnered the greatest amount of attention. ⋯ Existing meta-analyses of ketamine for CPSP are inconsistent in their findings, and studies of magnesium and methadone are even more limited. Overall, the evidence supporting NMDAR antagonists for CPSP is weak and we recommend that future studies focus on high-risk patients and potentially include combinations of NMDAR antagonists administered together for the longest duration feasible. The results of ongoing trials could have a major influence on the overall direction of the evidence supporting NMDAR antagonists in preventing CPSP.
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Chronic pain after surgery, also known as chronic postsurgical pain (CPSP), is recognized as a significant public health issue with serious medical and economic consequences. Current research on CPSP underscores the significant roles of both peripheral and central sensitization in pain development and maintenance. Peripheral sensitization occurs at the site of injury, through the hyperexcitability of nerve fibers due to surgical damage and the release of inflammatory mediators. ⋯ These glial cells release substances that further increase neuronal excitability, maintaining the sensitized state and contributing to persistent pain. The activation of antinociceptive systems is required for the resolution of pain after surgery, and default in these systems may also be considered as an important component of CPSP. In this review, we will examine the clinical factors underlying CPSP in patients and the mechanisms previously established in preclinical models of CPSP that may explain how acute postoperative pain may transform into chronic pain in patients.
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Reg Anesth Pain Med · Feb 2025
ReviewRisk factors for persistent postoperative opioid use: an entity distinct from chronic postsurgical pain.
Despite a decline in opioid prescriptions over the past decade, patients commonly receive opioid analgesics as a treatment for postoperative pain in the USA. One complication that patients may experience after surgery is persistent postoperative opioid use (PPOU), or opioid use beyond the typical recovery period. Often defined as beyond 3 months postsurgery, PPOU is frequently conflated with chronic postsurgical pain (CPSP), where pain persists well after the expected healing time following surgery. ⋯ Despite the overlap of some factors, studies typically employ different frameworks when examining PPOU and CPSP, with a biopsychosocial model applied for CPSP and little emphasis on an individual's social environment employed for PPOU. Additionally, existing studies predominantly rely on retrospective insurance claims data, which may not capture the full scope of risk factors. To fill gaps in understanding, investigations may prospectively assess and analyze patient-reported outcomes, implement similar frameworks, and concurrently measure both conditions to advance the scientific understanding of PPOU and CPSP.
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Reg Anesth Pain Med · Feb 2025
ReviewRole of peripheral nerve stimulation and percutaneous cryoneurolysis in preventing chronic postsurgical pain.
Poorly controlled pain during the acute postoperative period is associated with the development of persistent or 'chronic' pain lasting months or years after surgery. Relatively small trials suggest that local anesthetic-based peripheral nerve blocks lasting hours or a few days may decrease persistent postsurgical pain for some surgical procedures, but definitive data is lacking. Two possible alternatives-percutaneous cryoneurolysis and peripheral nerve stimulation-are analgesic modalities with the potential to provide weeks or months of pain relief following surgery. This increase in analgesic duration raises the possibility of decreased transition from acute to chronic postsurgical pain. ⋯ This review describes percutaneous cryoneurolysis and peripheral nerve stimulation for perioperative analgesia as well as the available evidence supporting their use to prevent persistent postsurgical pain.