Chronic postsurgical pain

Chronic postsurgical pain has significant implications for patients. If their functional state is severely compromised they may be unable to undertake rehabilitation programs. For example, following total joint arthroplasty, chronic pain around the affected prosthesis may lead to secondary deconditioning, poor mobility, venous thromboembolic disease and, eventually, loss of independence.

The prevalence of chronic postsurgical pain syndromes varies according to the procedure. The most common causes are limb amputation, arthroplasty, breast surgery, herniotomy, hysterectomy, spinal surgery and thoracotomy. It is important to identify risk factors for the transition of acute to chronic postsurgical pain (see Risk factors associated with the transition from acute to chronic pain ) and implement preoperative and postoperative preventive strategies early. Examples of modifiable risk factors are addressed in Modifiable risk factors for preventing chronic postsurgical pain.

Table 1. Modifiable risk factors for preventing chronic postsurgical pain
Risk factor	Preventive strategy
psychological	recognise preoperative anxiety, depression and catastrophising attempt to allay these by empathic dialogue and expectation management consider preoperative psychological intervention in complex patients education and expectation management are particularly important if patients have: few symptoms or indications for a procedure (eg asymptomatic hernia, cosmetic breast surgery, elective caesarean section) significant risk factors for the development of chronic postsurgical pain
preoperative pain	attempt to reduce high opioid doses preoperatively—data suggest poor outcomes in patients on high-dose opioids preoperatively diagnose and treat preoperative neuropathic pain—this may prevent pain becoming chronic; however, evidence is limited
postoperative severe acute pain	ensure appropriate acute pain management (both neuropathic and nociceptive)—see General principles of acute pain management encourage patients to be proactive with their pain management plan set daily goals with improved function the primary objective—goals include: develop a timetable for dressing, showering, attending rehabilitation avoid staying in bed unless they are medically unstable counsel patients about their analgesic therapy to avoid inadequate postoperative pain management upon discharge
surgical technique	if surgery is unavoidable, use less invasive surgical techniques (eg endoscopic surgery for inguinal herniorrhaphy) to reduce the risk of neural trauma
central sensitisation	consider regional anaesthesia or analgesia, and perioperative infusions of ketamine or lidocaine—these may reduce central sensitisation, a key contributor to chronic pain

The incidence and severity of chronic postsurgical pain decreases over the first 12 months after surgery. Prolonged pain following certain surgical procedures may be ameliorated by appropriate pain management within the first 12 months.

Neuropathic pain is common in chronic postsurgical pain because peripheral nerves are often unavoidably damaged during surgical procedures. Neuropathic pain is often underdiagnosed in the acute perioperative setting despite it being a risk factor for chronic postsurgical pain. Appropriate management of neuropathic pain may reduce the incidence of chronic postsurgical pain; however, stronger evidence is needed to confirm this.

If neuropathic pain is suspected, initiate first-line adjuvants—do not escalate opioid doses in an attempt to manage neuropathic pain because it is not consistently responsive to opioids. Manage acute neuropathic pain according to the advice outlined here. Manage chronic neuropathic pain according to the advice outlined here.