Role of multimodal analgesia in postoperative pain management

Pain management following surgery remains suboptimal, with many patients suffering from severe pain after surgery and still others developing chronic pain after surgery. [Pain Rep 2017;2:e588] Postoperative pain reduces patients’ quality of life, interferes with daily functioning, and has economic consequences in terms of longer recovery times and extended hospital stays. [Clinicoecon Outcomes Res 2019;11:169-177] At a recent scientific symposium held in Bangkok, Thailand, Associate Professor Sasikaan Nimmaanrat from the Prince of Songkla University, Hat Yai, discussed the role of multimodal analgesia in managing postoperative pain.

Treatment of postoperative pain
“The treatment goals for postoperative pain management include minimizing or eliminating discomfort, facilitating recovery, avoiding or managing adverse effects associated with treatment, and ensuring cost-effectiveness of therapy,” said Nimmaanrat.

Adequate management of acute postoperative pain is required for proper physiological and psychological function and to minimize the risk of perioperative complications. Conversely, insufficient management of postoperative pain may lead to chronic postsurgical pain (CPSP).

CPSP is one of the most frequent complications after surgery, with a median incidence of 20-30 percent at 6-12 months following surgery. Notably, preoperative opioid consumption is a risk factor for CPSP. Reducing the use of opioids by using multimodal analgesia, regional analgesia techniques, or ketamine could potentially reduce the incidence of CPSP. [BJA Educ 2022;22:190-196]

Multimodal analgesia approach
“The concept of multimodal analgesia was introduced in 1993 by Professor Henrik Kehlet as a technique to improve analgesia and reduce the incidence of opioid-related adverse events,” said Nimmaanrat.

“Traditionally, the mainstay of postoperative analgesia is opioid-based but emerging evidence supports a multimodal approach. While opioids alone provide good pain relief at rest, it is often insufficient to enable mobilisation and engagement with physiotherapy. Moreover, dose-dependent adverse effects related to opioid use often impairs patients’ postsurgical recovery. [Best Pract Res Clin Anaesthesiol 2018;32:101-111]

“Multimodal analgesia is achieved by combining different analgesics that act through different mechanisms and at different sites in the nervous system, resulting in additive or synergistic analgesia, with lower adverse effects for sole administration of individual analgesics (Table 1),” she added.

Efficacy of multimodal analgesia: Parecoxib + thoracic epidural analgesia
Thoracotomy results in severe postoperative pain potentially leading to chronic pain. A double-blinded prospective study evaluated the potential benefits of intravenous parecoxib on postoperative analgesia combined with thoracic epidural analgesia (TEA). Eighty-six patients undergoing thoracic surgery were randomly assigned to receive parecoxib or placebo intravenously half an hour before surgery and every 12 hours thereafter for 3 days, in addition to patient-controlled TEA.

Results showed that intravenous parecoxib improved postoperative analgesia provided by TEA, relieved stress response after thoracotomy, and restrained the development of chronic pain (Table 2). [J Thorac Dis 2016;8:880-887]

Cost-effectiveness of multimodal analgesia
A cost-consequence economic evaluation assessed direct medical costs related to opioid-related clinically meaningful events, based on data from a randomized controlled trial of parecoxib plus opioids vs opioids alone for 3 days following major non-cardiac surgery. The costs of clinically meaningful events were calculated using information on resource utilization and unit costs provided by clinical experts in China. [Clinicoecon Outcomes Res 2019;11:169-177]

Patients treated with parecoxib plus opioids reported significantly fewer clinically meaningful events than those treated with opioids alone (0.62 vs 1.04 events per patient, respectively, p<0.001). This suggests a reduction in medical resource utilization and reduced costs compared to use of opioids alone (Table 3). [Clinicoecon Outcomes Res 2019;11:169-177]

International guidelines highlight need for multimodal analgesia and limiting opioid use
The PROSPECT (PROcedure SPEcific Postoperative Pain ManagemenT) Working Group recommends the use of paracetamol and nonsteroidal anti-inflammatory drugs (NSAIDs) or COX-2-specific inhibitors administered either preoperatively or intra-operatively, and continued postoperatively as pain management for total knee arthroplasty. Other management options include single shot adductor canal block with peri-articular local infiltration analgesia intra-operatively, or intravenous dexamethasone intra-operatively. Opioids are considered a last resort or reserved only as a rescue analgesia. [Eur J Anaesthesiol 2022;39:743-757]

Notably, a meta-analysis of four studies showed that intravenous parecoxib is effective in reducing knee pain and opioid consumption in patients with TKA, without an increased risk of adverse effects related to parecoxib. [Int J Surg 2018;59:67-74]

The PROSPECT Working Group also published recommendations to reduce pain after laparoscopic cholecystectomy. They recommended the use of paracetamol and NSAIDs before or during operation with dexamethasone, while reserving opioids for rescue analgesia only, whereas gabapentanoids, intraperitoneal local anaesthetic, and transversus abdominis plane blocks are not recommended unless basic analgesia is not possible. [Br J Anaesth 2018;121:787-803]