Journal of Pain & Palliative Care Pharmacotherapy. 2014;28:51–53. ISSN: 1536-0288 print / 1536-0539 online DOI: 10.3109/15360288.2013.879249

EUROPEAN PERSPECTIVES ON PAIN AND PALLIATIVE CARE

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Chronic Postsurgical Pain: Prevention and Management Deepak Ravindran A B STRA CT Chronic postsurgical pain (CPSP) is a common problem, with up to a third of patients reporting persistent or intermittent pain 1 year after common operations. A proposed definition is pain that develops after a surgical procedure, which lasts at least 2 months, and where other causes and preexisting pain have been excluded. A variety of preoperative, intraoperative, and postoperative factors are thought to contribute to the pathogenesis of CPSP. Preventive strategies include effective postsurgical acute pain management, preoperative administration of gabapentin or pregabalin continued postoperatively, and considering the necessity of the surgical procedure itself and exploring alternatives. This report is adapted from paineurope 2013; Issue 3, ©Haymarket Medical Publications Ltd., and is presented with permission. paineurope is provided as a service to pain management by Mundipharma International, Ltd., and is distributed free of charge to health care professionals in Europe. Archival issues can be accessed via the Web site: http://www.paineurope.com, at which European health professionals can register online to receive copies of the quarterly publication. KEYWORDS chronic, pain, postoperative, postsurgical

• The possibility that the pain is continuing from a preexisting problem has been excluded

In the last 10 years, there has been increasing recognition of the fact that a significant percentage of patients report chronic pain after a wide variety of surgeries. Chronic postsurgical pain (CPSP) is a major problem with societal consequences and effect on quality of life. Up to about a third of patients report persistent or intermittent pain 1 year after common surgical procedures.1 It is therefore important to identify possible risk factors, understand pathological mechanisms, and establish preventive strategies.

PREVALENCE A survey of 5130 patients attending outpatient pain clinics revealed that 22.5% of patients cited surgery as their main cause of chronic pain.3 The figure for the general population is likely to be significantly higher, since not all patients come into secondary care. A more recent cross-sectional survey of 12,982 participants showed that among respondents who had undergone surgery more than 3 months prior to being surveyed (N = 2043), 40.4% reported chronic pain, 18.3% reported moderate to severe pain, and sensory abnormalities were reported by 24.5%.4 The common surgical procedures include inguinal hernia repair and breast, orthopedic, and cardiothoracic surgery.1 The incidence of chronic pain is 12% for patients undergoing hernia repair5 and is now the most common long-term problem after such surgery.6 Rates of CPSP are much higher after mastectomy with reconstruction (49%) compared with mastectomy alone (31%).7

DEFINITION The following criteria2 have been suggested to define CPSP:

• Pain that develops after a surgical procedure • Pain lasting at least 2 months • Other causes such as chronic infection have been excluded Deepak Ravindran, MD, FFPMRCA, FIPP, is a Consultant in Anesthesia and Pain Management at the Royal Berkshire Hospital, Reading, UK. Address correspondence to: Dr. Deepak Ravindran. (E-mail: info@ berkshirepainclinic.co.uk).

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Journal of Pain & Palliative Care Pharmacotherapy

TABLE 1.

Putative Risk Factors for Chronic Postsurgical Pain8

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Preoperative factors

Intraoperative factors

Postoperative factors

• Psychological factors such as lack of resilience and catastrophizing leading to vulnerability • Preexisting pain syndromes, e.g., fibromyalgia, headache, low back pain, irritable bowel syndrome • Preoperative pain in surgical site • Younger age group • Genetic and environmental components • Nerve handling and injury • Type of incision • Not utilizing nerve-sparing techniques • Type of surgery (location, use of mesh, stapling, sternal wire) • Presence of acute postoperative pain • Disease recurrence at surgical site • Use of chemotherapy or radiotherapy

RISK FACTORS A number of putative risk factors have been identified that may contribute to development of CPSP (Table 1).8 Genetic susceptibility is likely to play a role in the development of CPSP. For example, singlenucleotide polymorphisms coding for the catecholO-methyltransferase enzyme are associated with the development of chronic pain conditions such as temporomandibular joint disorder.9 Genetic variability in the expression of enzymes responsible for neurotransmitter synthesis in the dorsal root ganglion is associated with persistent pain after lumbar discectomy.10 There are no studies as yet that have included all the above factors; therefore, there is no clear consensus on the mechanisms involved and hence prevention and management of the problem.

PREVENTIVE STRATEGIES AND TREATMENT A positive correlation between sensory abnormalities and pain as reported7 suggests that neuropathic mechanisms are responsible in a majority of pain cases.1 Once nerve injury has occurred, a wide variety of inflammatory mechanisms are activated, leading to peripheral and central sensitization by release of various neurotransmitters. Our knowledge of acute pain physiology and its transition to chronic pain would suggest that one therapeutic strategy or single-modality treatment is unlikely to work once this diffuse and complex neural pathway activation occurs.

This increase in awareness of CPSP has led to a huge body of research looking into preemptive and preventive strategies. The challenge is to accurately identify at-risk patients and target suitable interventions. Preemptive epidural analgesia (regional analgesia commenced before surgery) has not shown much benefit for preventing CPSP. A meta-analysis of preemptive epidural compared with epidural commenced after completion of thoracic surgery did not affect development of CPSP.11 Many of the risk factors are difficult to influence or alter, but there is no doubt that severity of acute postoperative pain influences CPSP.1 Effective treatment of acute pain after surgery can reduce the incidence of CPSP by preventing sensitization of the CNS.1 A combined systematic review and metaanalysis looked at the utility of using gabapentin and pregabalin in preventing CPSP.12 Eight trials were included in the meta-analysis; they showed that six of the gabapentin trials demonstrated moderate to large reduction in the development of CPSP, whereas two of the pregabalin trials showed a very large reduction in development of CPSP.12 Preemptive analgesia using drugs such as gabapentin or pregabalin (off-label) administered preoperatively and continued postoperatively are now part of most procedure-specific pain management protocols in the UK, and are included in enhanced recovery pathways. Regional blockade by itself is often insufficient; therefore, a multimodal approach utilizing regional blockade (central/peripheral), nonsteroidal anti-inflammatory drugs (NSAIDs), drugs for neuropathic pain, and other analgesics including opioids is the best way forward. A major preventive factor often less discussed is not having the surgical procedure itself. Inappropriate or unnecessary surgery needs to be prevented. Alternatives to surgery should be explored and patients must be made aware of risks so that a truly informed choice is made. Public education should be improved to both patients and their caregivers in order to help remove the belief that something must have gone wrong at the time of surgery. Once CPSP has occurred, it is difficult to cure, but there are a number of interventions that can be helpful in reducing pain. Initial management in primary care would include patient education, counseling, and self-management followed by the use of antineuropathic medication such as amitriptyline, gabapentin, and pregabalin. Depending on the extent and severity of the pain and its effect on quality of life, pain specialists can employ a variety of interventions such as local infiltrations of steroids13,14 and diagnostic nerve blocks followed by neuromodulation techniques within a multidisciplinary model. Journal of Pain & Palliative Care Pharmacotherapy

European Perspectives on Pain and Palliative Care

Although the evidence base for these techniques is limited, when chosen appropriately, they can provide hope.

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CONCLUSION CPSP is a significant public health issue. As its development is likely to be multifactorial, large-scale, multicenter, randomized studies are urgently needed to aid better understanding of CPSP. Meanwhile, our aim should be to minimize unnecessary and inappropriate surgery, provide sustained and effective perioperative pain relief, and detect and treat postoperative neuropathic pain in an early and aggressive manner using a multimodal strategy. Declaration of interest: The author reports no conflicts of interest. The author alone is responsible for the content and writing of the paper.

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REFERENCES [1] Kehlet H, Jensen TS, et al. Lancet. 2006;367:1618–1625. [2] Macrae WA, Davies HT. Chronic postsurgical pain. In: Crombie IK, Croft PR, et al., editors. Epidemiology of Pain. Seattle: IASP Press; 1999. [3] Crombie IK, Davies HT, et al. Pain. 1998;76:167–171. [4] Johansen A, Romundstad L, et al. Pain. 2012;153:1390–1396. [5] Aasvang E, Kehlet H. Br J Anaesth. 2005;95:69–76. [6] Jenkins JT, O’Dwyer PJ. BMJ. 2008;336:269–272. [7] Wallace MS, Wallace AM, et al. Pain. 1996;66:195–205. [8] Kehlet H. Persistent postsurgical pain: surgical risk factors and strategies for prevention. In: Castro-Lopes J, Raja S, et al., editors. Pain. 2008: An Updated Review. Seattle, IASP Press; 2008. [9] Diatchenko L, Slade GD, et al. Hum Mol Genet. 2005;14:135–143. [10] Searle RD, Simpson KH. Contin Educ Anaesth Crit Care Pain. 2010;10:12–14. [11] Bong CL, Samuel M, et al. J Cardiothorac Vasc Anesth. 2005;19:786–793. [12] Clarke H, Bonin RP, et al. Anesth Analg. 2012;115:428–442. [13] Aroori S, Spence RA. Ulster Med J. 2007;76:136–140. [14] Macrae WA. Br J Anaesth. 2001;87:88–98.

Chronic postsurgical pain: prevention and management.

Chronic postsurgical pain (CPSP) is a common problem, with up to a third of patients reporting persistent or intermittent pain 1 year after common ope...
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