SEPTEMBER 22, 2023
Originally published by our sister publication Anesthesiology News
HOLLYWOOD, Fla.—Contrary to popular belief, the use of peripheral nerve blocks seems to have its greatest effect in terms of reducing complications in total joint arthroplasty (TJA) patients with lower comorbidity burden, regardless of age, according to a new investigation.
The nationwide population-based study concluded that relative to systemic analgesia, use of peripheral nerve blocks reduced complications and hospital
Originally published by our sister publication Anesthesiology News
HOLLYWOOD, Fla.—Contrary to popular belief, the use of peripheral nerve blocks seems to have its greatest effect in terms of reducing complications in total joint arthroplasty (TJA) patients with lower comorbidity burden, regardless of age, according to a new investigation.
The nationwide population-based study concluded that relative to systemic analgesia, use of peripheral nerve blocks reduced complications and hospital resource utilization.
“Most clinicians are familiar with the idea that peripheral nerve blocks are superior to systemic analgesia in terms of pain outcomes,” said Stavros G. Memtsoudis, MD, PhD, a clinical professor of anesthesiology at the Hospital for Special Surgery, in New York City. “But the next step in the research is to determine if it can also affect complication rates.”
To find which patient populations would benefit most from peripheral nerve blocks, investigators used the Premier Healthcare claims database to identify a cohort of patients undergoing inpatient, elective TJA using ICD-9 (International Classification of Diseases, Ninth Revision) procedure codes. Exclusion criteria included outpatient surgery (n=26,698), unknown sex (n=322), unknown discharge status (n=1,493), undergoing surgery at a hospital that performed fewer than 30 TJA procedures (n=621) and patient age less than 18 years (n=570).
The study’s primary exposure of interest was the use of a peripheral nerve block, defined by billing and Current Procedural Terminology codes on the day of surgery. Participants were stratified by groups based on age and Charlson-Deyo Comorbidity Index group.
The participants were categorized in three groups: group Y, younger than 65 years; group M, 65 to 75 years; and group O, older than 75 years. Charlson-Deyo Comorbidity Index groups were also divided into three groups: group 1, those without preexisting comorbidities; group 2, those with one to two comorbidities; and group 3, those having three or more comorbidities. In total, nine subgroups were created: Y(1), M(1), O(1), Y(2), M(2), O(2), Y(3), M(3) and O(3).
The researchers applied mixed-effects models to measure associations between outcomes and the use of peripheral nerve blocks for the overall population and each of the nine subgroups. Multivariate models adjusted for age, sex, race, insurance type, hip or knee arthroplasty, anesthesia type, hospital location, teaching hospital, hospital bed size, region and year of surgery.
In a presentation at the 2023 spring meeting of the American Society of Regional Anesthesia and Pain Medicine, Memtsoudis reported that the overall study sample comprised 2,822,199 TJA cases performed in 887 hospitals (abstract 4193). Of these cases, 15.5% (n=438,105) received a peripheral nerve block. Nerve block use increased from 9.5% in 2006 to 18.9% in 2019. Peripheral nerve block was used least in young people with three or more comorbidities (13.9%), while the highest rate was seen in middle-aged patients without a comorbidity (16.3%).
The study found that among the overall population, peripheral nerve block use was significantly associated with many benefits, including significant decreases in the odds of respiratory complication (odds ratio [OR], 0.96; 95% CI, 0.93-0.99; P=0.01), acute renal failure (OR, 0.90; 95% CI, 0.86-0.93), delirium (OR, 0.91; 95% CI, 0.86-0.96; P<0.01), ICU admission (OR, 0.87; 95% CI, 0.84-0.91; P<0.01), high opioid consumption during hospitalization (OR, 0.83; 95% CI, 0.82-0.84; P<0.01), and prolonged length of stay (OR, 0.95; 95% CI, 0.94-0.97; P<0.01).
Analyses of the subgroups revealed decreased odds among the O(1) and Y(2) groups for any respiratory complications; acute renal failure in the Y(1), O(1) and M(2) subgroups; and delirium in the O(1) group. When compared with patients who did not receive a peripheral nerve block, the risk for ICU admission was reduced across all ages with no comorbidity and the patients in Y(2) and O(2).
These findings, Memtsoudis said, help illustrate the general beneficial effects of peripheral nerve blocks on a host of outcomes following TJA, regardless of age and comorbidity burden. However, these positive effects were not entirely consistent across all subgroups.
The most consistent reduction in the odds of complications and resource utilization was observed in the older population with no comorbidity burden. This finding might reflect the possibility that comorbidity burden has a greater impact on complication risk, while the use of peripheral nerve blocks might be insufficient to consistently influence outcome. As such, there may be an optimal baseline risk level at which use of peripheral nerve blockade yields the greatest benefit.
“We found that the people who most benefit from peripheral nerve blocks are healthy patients, particularly older healthy patients,” Memtsoudis said. “It’s logical, actually, because if you think about it, peripheral nerve block is just one intervention out of many that these patients undergo, and it’d be naive to believe that one intervention can erase all other risk factors and somehow ensure that a patient does not experience a complication.”
These findings contradict conventional wisdom, which implies peripheral nerve blocks are best used in sicker patient populations.
“I think there are anesthesiologists who restrict their practice of regional anesthesia to the old and sick because they believe that these are the people who benefit most,” Memtsoudis explained. “But I would hope that by looking at these data, people will realize that’s not the case, and that expanding the intervention to healthier populations on a more routine basis really has some merit.”
Edward R. Mariano, MD, MAS, noted that the study’s findings are consistent with those from a recent systematic review and meta-analysis (Reg Anesth Pain Med 2021;46[11]:971-985), which resulted in recommendations favoring peripheral nerve block use in primary lower-extremity joint arthroplasty.
“The lack of advantage in patients with higher comorbidity burden should not discourage anesthesiologists from using peripheral nerve blocks in this population,” said Mariano, a professor and the senior vice chair of anesthesiology, perioperative and pain medicine at Stanford University School of Medicine, in California. “Not seeing a decrease in complications in this population is not likely an issue with peripheral nerve blocks, but rather due to the greater influence of chronic disease on postoperative complications. In other words, peripheral nerve blocks are not enough to overcome the innate risk of having a complication in patients who carry the heaviest disease burden.”
Mariano, a member of the Anesthesiology News editorial advisory board, noted that he would continue to recommend peripheral nerve blocks in older patients undergoing lower-extremity joint arthroplasty, regardless of preoperative health status.
“Even if there is no association with decreased postoperative complications for the sickest ones, they all benefit from the opioid-sparing effects and targeted analgesia in the short term,” he added.
—By Michael Vlessides
Mariano and Memtsoudis reported no relevant financial disclosures.
