Chronic Post-Surgical Pain

Chronic post-surgical pain occurring at the site of incision or related to surgery and persists a month longer than it takes for most injuries to fully heal. May be:

Chronic pain:

Epidemiology and Risk Factors

Risk factors are proportional to post-operative opioid consumption

Surgical Factors: * Type * Breast * Inguinal hernia * Thoracics * Trauma * Burns * Amputation * Involving nerves

Patient Factors: * Chronic Pain * Uncontrolled acute pain * Intensity * Duration * Analgesic consumption
CPSP incidence ↑ with more analgesic consumption. * Young * Female * Catastrophising
How you think. * Depression/Anxiety
How you feel. * Employment status * Educational level * Marital status * Compensation status * Preoperative opioid use

Pathophysiology

Multiple pathways:

  • Persistent inflammation
  • Nerve injury
  • Central sensitisation
    • ↑ Receptor density
    • ↑ Sensitivity to all stimulatorly neurotransmitters
    • Touch-pain pathway crossover
    • Hyperalgesia
    • Pain memory and experience

Aetiology

Clinical Manifestations

Pain, with:

  • Hyperalgesia
  • Allodynia

Associated with disturbances to:

  • Mood
  • Sleep
  • Enjoyment of life

Diagnostic Approach and DDx

Investigations

Management

Preventative:

  • Preemptive analgesia
    Analgesia prior to nociceptive stimulus; e.g.
    • Epidural
      Reduces CPSP after thoracotomy.
    • Spinal
    • Paracetamol
    • Gabapentinoids
  • Ketamine
    Perioperative ketamine reduces phantom limb pain magnitude but not incidence.

Anaesthetic Considerations

Marginal and Ineffective Therapies

Complications

Prognosis

Key Studies

References

  1. Katz J, Weinrib AZ, Clarke H. Chronic postsurgical pain: From risk factor identification to multidisciplinary management at the Toronto General Hospital Transitional Pain Service. Canadian Journal of Pain. 2019 Jul 15;3(2):49–58.
  2. Glare P, Aubrey KR, Myles PS. Transition from acute to chronic pain after surgery. The Lancet. 2019 Apr;393(10180):1537–46.