Chronic postsurgical pain: is there a possible genetic link?

Abstract

Persistent or chronic postsurgical pain (CPSP) has been defined as 'pain persisting beyond 2 months'. The cutoff limit of 2 months has been controversial, and some researchers argue for a 3-month period for the definition of CPSP. Multiple mechanisms, including both patient and surgical, have been shown to influence this transition. Patient factors include age, gender, anxiety, depression, somatisation, catastrophising, pre-existing pain anywhere and pain at the site of surgery. The various surgical factors include site and nature of surgery, infection, inflammation and repeat surgery. There is evidence that pre-or post-op chemotherapy and radiotherapy can also contribute towards the chronification of pain after surgery. The question of why pain following surgery or trauma persists long after the normal healing time is not yet fully explained by current evidence. This is frustrating to healthcare providers and intensely disappointing to the patients, many of whom suffer in silence for years. Genetics is now being shown to influence both the onset and the perpetuation of chronic pain in the susceptible patient. The main mechanisms are believed to be 'single nucleotide polymorphisms' (SNPs) and 'epigenetics', both of which will be discussed, with current and ongoing research and evidence, in this review. The influence of SNPs has not been replicated in recent studies and researchers advise caution in interpreting past studies. More research is needed to demonstrate the involvement of epigenetics as well as linking SNPs to the susceptible patient's journey.

Assessment and pathophysiology of pain in cardiac surgery

“… 54 , 82 In addition, epigenetic analysis may lead to identification of mechanisms critical to the development of chronic pain after an injury, thus providing new pathways and target mechanisms for future drug development and individualized medicine. 83 …”

Risk factors for severe acute pain and persistent pain after surgery for breast cancer: a prospective observational study

“…Further, few studies have evaluated potential genetic predictors of pain in this patient population. Indeed, it has been shown that certain genetic variations could potentially influence both the onset of acute pain and the development of persistent postsurgical pain 13. Thus, a better understanding of individual variability in patient characteristics of postsurgical pain (eg, genetic, surgical, and psychological) will help identify a high-risk subset of patients who are likely to develop severe acute pain and persistent pain, and also promote the emerging concept of the role of precision medicine in postoperative and long-term pain management of patients who underwent breast surgery.…”

Chronic pain after breast surgery: incidence, associated factors and impact on quality of life, an observational prospective study

“…There is, however, no clear consensus about the de nition of "high risk patients" for CPBS, thus making it di cult to identify those subjects who might bene t the most from careful, early pain assessment. A complex multidisciplinary, multiparametric approach involving also psychosocial and genetic factors has been suggested to perioperatively stratify patients and identify those at high risk of developing CPBS (Bortsov et al 2020;James 2017). Nevertheless, because genotyping is expensive and usually unfeasible in routine clinical practice, strategies for risk strati cation are currently based on the evaluation of those clinical and anamnestic, pre-and intraoperative predictors of CPBS that have already been identi ed in the literature.…”