Transient benefit of ICNB may lead to inadequate pain control at 48 hours

Intercostal nerve block (ICNB) analgesia with local anesthesia led to reduced pain in the first 24 hours after thoracic surgery, with 24-hour pain scores that were noninferior to thoracic epidural analgesia (TEA) and marginally inferior to paravertebral block (PVB), a systematic review and meta-analysis showed.

Compared with ICNB, however, TEA and PVB were associated with larger decreases in postoperative morphine milligram equivalents (MMEs) at 48 hours, reported Juan Cata, MD, of University of Texas in Houston, and co-authors.

“This study found that ICNB was safe and beneficial for adults undergoing thoracic surgery, providing a reduction in pain during the first 24 hours after thoracic surgery; ICNB may be most beneficial for cases in which thoracic epidural or paravertebral block analgesia are not indicated,” Cata and colleagues wrote in JAMA Network Open.

“The data suggested that the benefit of ICNB analgesia decreases progressively and disappears at 24 to 48 hours after surgery,” the researchers noted. “Reliance on ICNB after this period may result in an abrupt lack of analgesia or rebound pain, represented by higher pain scores at 24 hours after surgery for dynamic pain and 48 hours after surgery for static pain. This finding is relevant because the severity of acute pain may be the main measure associated with the occurrence of chronic pain.”

Cata and co-authors identified 66 relevant studies for meta-analysis through July 2020 (n=5,184 patients overall with mean age 53.9 and 41% women). Quantitative analysis included 59 studies (n=3,325). The group included studies with adult patients undergoing cardiothoracic surgery who had ICNB administered with local anesthesia via single injection, continuous infusion, or a combination. Most included studies used single-injection ICNB.

“Marked differences (e.g., crossover studies; timing of the intervention—intraoperative versus postoperative; blinding; and type of control group) were observed in the design and implementation of studies,” the researchers noted.

Results for ICNB were compared with those for systemic analgesia and forms of regional analgesia including TEA and PVB. The primary outcomes were postoperative pain intensity on a 10-point scale and opioid consumption in MMEs, both evaluated in in one of five specific postoperative time intervals. Effective analgesia was defined as at least a 1-point difference in pain intensity score.

The analysis considered pain at rest (static) and with movement (dynamic). On a 10-point pain scale:

  • ICNB was associated with lower pain after surgery than systemic analgesia for lower static pain (0-6 hours after surgery, mean score difference −1.40 points, 95% CI −1.46 to −1.33; 7-24 hours after surgery, mean score difference −1.27, 95% CI −1.40 to −1.13).
  • ICNB also was associated with lower dynamic pain; during the same time intervals, mean score differences were −1.66, 95% CI −1.90 to −1.41, and −1.43 points, 95% CI −1.70 to −1.17, respectively.
  • ICNB was noninferior to TEA (mean score difference in worst dynamic pain at 7-24 hours after surgery, 0.79 points, 95% CI 0.28-1.29 points) and marginally inferior to PVB (mean score difference in worst dynamic pain at 7-24 hours after surgery: 1.29, 95% CI 1.16 to 1.41 points).

ICNB had opioid-sparing effects compared with systemic analgesia at 48 hours after surgery, with mean difference of −10.97 MMEs, 95% CI −12.92 to −9.02. However, ICNB was associated with higher MME values 48 hours post-operatively compared with TEA (mean difference 48.31 MMEs, 95% CI, 36.11-60.52 MMEs) and PVB (mean difference 3.87 MMEs, 95% CI 2.59-5.15 MMEs).

Secondary outcomes for 30-day postoperative complications showed reduced nausea and vomiting with ICBN with respect to systemic analgesia, but increased nausea and vomiting risk compared with TEA or PVB. Cardiovascular complications were similar for ICNB and systemic analgesia but were reduced compared with TEA.

In an accompanying editorial, Joseph Forrester, MD, MSc, of Stanford University, and co-authors noted that “pain relief from ICNB with local analgesia is transient, lasting a maximum of 48 hours for a single-injection application, which was the technique used among most patients included in this meta-analysis.”

“Inadequate pain control in the later acute postoperative period (4 or more days after a procedure) is associated with increases in the risk of chronic pain, decreases in physical function, and worse quality of life, underscoring the importance of prompt and durable pain control,” the editorialists wrote.

“Pain after surgery often outlasts current interventions, leaving patients in need of additional systemic therapy until they reach their pain-free state, or at least a pain nadir,” they added.

Three studies in the meta-analysis compared ICNB with intercostal cryoneurolysis with ICNB, all of which were conducted before 1990, Forrester and colleagues noted. “However, intercostal cryoneurolysis, or cryoablation, is experiencing a resurgence as a pain control modality for patients undergoing thoracic surgery, with techniques and technologies rapidly improving,” they observed.

Limitations of the present study include a high risk of bias in at least one domain of most studies included in the meta-analysis. Most studies did not include complications as a primary or secondary outcome, the researchers noted.

  1. Intercostal nerve block (ICNB) analgesia with local anesthesia led to reduced pain after thoracic surgery, with 24-hour pain scores noninferior to thoracic epidural analgesia (TEA) and marginally inferior to paravertebral block (PVB), a systematic review and meta-analysis showed.

  2. Compared with ICNB, however, TEA and PVB were associated with larger decreases in postoperative morphine milligram equivalents (MMEs) at 48 hours.

Paul Smyth, MD, Contributing Writer, BreakingMED™

Cata reported no disclosures.

Forrester reported no disclosures.

Cat ID: 492

Topic ID: 97,492,730,914,192,925,492

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