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Preemptive and Preventive Analgesia for Chronic Postsurgical Pain

A Q&A with Lynn Cintron, MD, MS
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Chronic postsurgical pain is a major clinical problem found worldwide. This pain differs in quality and location from pain experienced prior to surgery and is usually associated with neuropathic pain caused by surgical injury. To better understand the risk factors for chronic postsurgical pain and the latest clinical evidence on preemptive and preventive analgesia strategies to prevent this condition, Practical Pain Management spoke with Lynn Cintron, MD, MS, an adjunct associate clinical professor at the University of California, Irvine.

Addressing the risks associated with post-surgical pain.

How do better preemptive/preventive analgesia influence recovery and outcomes from common surgeries?

Dr. Cintron: Chronic postsurgical pain (CPSP) is a profound problem, with moderate to severe CPSP (ie, pain lasting more than 3 to 6 months after surgery) affecting up to 10% to 12% of patients undergoing common surgeries.1,2 This incidence may be underestimated because CPSP is often underdiagnosed.1 In fact, the International Association for the Study of Pain (IASP) designated 2017 as the “IASP Global Year Against Pain After Surgery.”3

There is a strong body of clinical data showing that preventive analgesia decreases pain and opioid use in acute care.4-7 Studies show other benefits, such as decreased length of hospital stay, improved function, better patient satisfaction, and improved cognitive function postoperatively.6-9

A recent study by Deng et al studied pre-emptive analgesia in the elderly, with continuous femoral nerve blocks for total knee arthroplasty.8 Results showed a decrease in visual analog scale (VAS) pain scores in recovery and decreased postoperative cognitive dysfunction.

More high-quality studies, addressing various types of surgery and different age groups, including children, are needed to see the benefit of relieving pain beyond 3 months after surgery or trauma.

How are preemptive and preventive analgesia different?

Dr. Cintron: Preemptive analgesia occurs prior to the incision of surgery or traumatic injury. Pre-emptive analgesia is ideal, but not always possible in some clinical settings (eg, traumatic injury).

Preventive analgesia is a perioperative intervention as it may occur prior to, during, and immediately after the event. While preventive analgesia can reduce acute postoperative pain, minimizing the development of chronic pain conditions can only be successful in combination with intraoperative and postoperative pain therapy, as well as social and psychological support as indicated.5

It is difficult to make definitive conclusions regarding the efficacy of preventive analgesia because data from human clinical studies on this strategy are limited. Earlier studies have been small in size, have combined multiple types of surgery, or may have studied only males and, thus, do not account accurately for the differences in pain perception between men and women. By developing large data registries, researchers will be able to make more accurate predictions on chronic and perioperative risk factors to optimize patient evaluation and treatment.

What are optimal regimens for pre-emptive/preventive analgesia? Is multimodal analgesia advised?

Dr. Cintron: Multimodal analgesia is recommended, when possible, as it has a synergistic benefit on pain relief. Animal studies have found there is a critical time frame before and immediately after nerve injury in which specific interventions can reduce the incidence of chronic neuropathic pain behaviors.4 In animal models, the following agents have demonstrated efficacy in reducing pain behaviors weeks after treatment with perineural local anesthetics, systemic intravenous local anesthetics, perineural clonidine, systemic gabapentin, tricyclic antidepressants, and minocycline. The translation of this work to humans suggests similar benefits.4

Epidurals, regional blocks, and infusions placed preoperatively appear effective at reducing nociceptive input, which can lead to central sensitization. This can reduce the likelihood of developing CPSP. Preoperative epidural infusions have been shown to reduce the use of opioids in patients and to reduce the length of stay in the recovery room.6 A retrospective review favored regional anesthesia for the prevention of chronic pain at 6 months after thoracotomy (odds ratio, 0.33) and paravertebral block for breast cancer surgery (odds ratio, 0.37) at 5 to 6 months after surgery.10

Several randomized controlled studies have demonstrated a benefit of intravenous (IV) ketamine for pain, although this depends on the type of surgery and the patient population studied. In thoracic surgery, pre-emptive IV ketamine (1.0 mg/kg) significantly decreased pain scores (P= 0.01), morphine use (P < 0.001), and C-reactive protein (P < 0.001), a sign of inflammation, in the recovery room compared with placebo.9

In a recent study of opioid-dependent patients, a complicated patient group that usually requires higher opioid doses after surgery, they received a ketamine infusion during lumbar spine surgery. Six months postoperatively, the investigators found significantly greater improvement in back pain compared to the placebo group (P = 0.005).11 Another study of opioid-dependent patients who underwent spine surgery with ketamine infusions found postoperative pain benefit at 6 weeks. Data revealed a 71% decrease in opioid use for this group, compared to placebo.12

Last updated on: September 27, 2017
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