ReviewChronic post-surgical pain: Epidemiology and clinical implications for acute pain management
Introduction
Chronic or ‘persistent’ post-surgical pain (CPSP) is defined as pain of at least 2 months duration which has developed after a surgical procedure, where other causes such as disease recurrence or a pre-existing pain syndrome have been excluded [1].
CPSP is an under-recognised and prevalent healthcare problem. Surgery contributed to the development of chronic pain in approximately 20% of patients attending pain management clinics in Northern Britain [2]. The incidence of chronic neuropathic pain 1 year after surgery is between 0.5% and 1.5% [3]. In Canada, there are an estimated 72 000 new cases of CPSP each year [4] and in the United States of America, the incidence of complex regional pain syndrome (CRPS) following orthopaedic surgery is estimated at between 74 000 and 191 000 new cases per year [5]. Given these staggering figures and the fact that chronic pain is associated with significant disability and health care utilisation [6], CPSP should be considered a “silent epidemic” that deserves further attention by health care professionals and patients alike.
Section snippets
Epidemiology and ‘risk factors’ for CPSP
Most studies examining CPSP report on incidence rather than other pain-related factors such as intensity or qualitative features. However, Bruce et al. noted that most patients, across a wide variety of CPSP disorders, used ‘sensory-discriminative’ features of the McGill Pain Questionnaire to describe their pain. The most frequent descriptive words were aching, annoying, numb, sharp, stabbing and tiring. Chronic post-mastectomy pain patients reported higher pain rating intensity scores and used
Wound hyperalgesia and CPSP
The area of punctate mechanical hyperalgesia or allodynia around a surgical wound on quantitative sensory testing (QST) (with Von Frey hairs) up to 72 h post-abdominal surgery, correlated with the incidence of CPSP at 6 months (R = 0.81; p < 0.001) but not with acute post-surgical pain, in randomised controlled trials (RCTs) using peri-operative intravenous ketamine or epidural analgesia [30], [31], [32].
In contrast, there was no correlation between the area of stump allodynia, acute pain outcomes
Aetiology of CPSP
CPSP has a multifactorial aetiology and pathology, principally nerve injury and wound inflammatory response, leading to peripheral and central sensitisation and the development of ‘pathological pain’ (severe acute or persistent pain), hyperalgesia or allodynia in the region of the surgical incision.
Central sensitisation may be defined as a state of central nervous system (dorsal horn, thalamus and cortex) ‘hyperactivity’ (including pain ‘amplification’ and ‘memorisation’), due to intensive or
Prevention of CPSP
Although CPSP is a complex bio-psycho-social phenomenon, the utility of a multi-dimensional approach, using a combination of preventive analgesia, modified surgical techniques, psychotherapy, physical rehabilitation, public health, educational and occupational approaches has not yet been validated.
The role of an acute pain service
Severe acute post-surgical pain is common [71] and is a potential risk factor for CPSP [8]. Acute pain services (APS) reduce acute post-operative pain [72] and may therefore reduce CPSP, although this ‘link’ has not been studied directly. An APS may facilitate identification and surveillance of ‘at risk’ patients and optimise the use of preventive analgesia techniques such as epidurals or intravenous ketamine infusions. Ideally, a ‘multidisciplinary APS’ should provide patient education,
Conclusion
Chronic post-surgical pain (CPSP) is an under-recognised and prevalent healthcare problem associated with significant morbidity and potential economic costs. Risk factors include the type of surgery, particularly where there is likelihood of significant nerve or tissue damage, pre-operative pain, moderate-to-severe acute post-operative pain, neurotoxic radio or chemotherapy and psycho-social factors.
CPSP has a multifactorial aetiology including nerve injury and wound inflammatory response,
References (74)
Chronic pain after surgery
Br J Anaesth
(2001)- et al.
Neuropathic pain in the acute pain service: a prospective study
Acute Pain
(2002) - et al.
Prevalence and characteristics of post coronary artery bypass graft surgery pain
Pain
(2001) - et al.
Pain after breast surgery: survey of 282 women
Pain
(1996) - et al.
Pain and quality of life following radical retropubic prostatectomy
J Urol
(1998) - et al.
The effect of cyclooxygenase-2 inhibition on acute and chronic donor-site pain after spinal-fusion surgery
Reg Anesth Pain Med
(2006) - et al.
The prevalence of chronic chest and leg pain following cardiac surgery: a historical cohort study
Pain
(2003) - et al.
A retrospective cohort study of post mastectomy pain syndrome
Pain
(1999) - et al.
The morbidity, time course and predictive factors for persistent post thoracotomy pain
Eur J Pain
(2001) Preventing chronic pain after surgery: who, how, and when?
Reg Anesth Pain Med
(2006)