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Flashcards in Chapter 35 Chronic Pain after Surgery Deck (20):

chronic pain after surgery definition

The pain should have developed after a surgical
2. The pain should be of at least 2 months duration.
3. Other causes of the pain should be excluded, such as
recurrence of malignancy or infection.
4. The possibility that the pain is continuing from a
preexisting problem should be explored and exclusion


Factors Associated with Development of Chronic Pain after Surgery
Preoperative Factors

Moderate–severe pain of >1 mo duration
Repeat surgery
Psychological factors


Factors Associated with Development of Chronic Pain after Surgery
Intraoperative Factors

Surgical approach with risk of nerve injury
Nonlaparoscopic technique
Surgery in low-volume center


Factors Associated with Development of Chronic Pain after Surgery
Postoperative Factors

Moderate–severe acute pain
Neurotoxic chemotherapy
Radiation therapy to site


A consistent factor associated with development of acute
and CPSP across many types of surgery is the presence

of preoperative pain. The
presence of preoperative pain is a risk factor for the development of early acute postoperative pain, pain in the
days, weeks, and months following surgery.


independent predictors of severe pain

preoperative pain, female gender, younger age,
incision size, and type of surgery


A very consistent factor in the
development of CPSP is the presence of

either severe preoperative pain, postoperative pain, or both.


Several factors may explain the consistent relationship
of preoperative and severe acute postoperative pain predicting
CPSP, including the following:

1. Preoperative opioid tolerance leading to underestimation and underdosing of postoperative opioid analgesics.
2. Intraoperative nerve damage and the associated
CNS changes such a central sensitization and “wind-up.”
3. Sensitization of pain nociceptors in the surgical
4. Postoperative ectopic activity in injured primary
afferents and collateral sprouting from intact nociceptive Ad-afferents neighboring the area supplied
by injured afferents.
5. Central sensitization induced by the surgery and
maintained by further input from the surgical site
during the healing process.


Several factors may explain the consistent relationship
of preoperative and severe acute postoperative pain predicting
CPSP,7 including the following:

6. Structural changes in the CNS (plasticity) induced by nociceptive inputs with
consequent reduction in normal inhibitory control
systems leading to “centralization” of pain
and development of pain memories.
7. Heretofore unidentified pain genes that may confer
increased risk of developing both severe acute
and chronic postsurgical pain.
8. Psychological and emotional factors such as emotional numbing and catastrophizing
9. Social and environmental factors such as solicitous
responding from significant others and social support
10. Response bias over time—that is, some individuals
have a tendency to report more pain than other
11. Publication bias in which findings of a significant
relationship between pain before and after surgery
are published, whereas negative findings are rejected
and do not get published.


psychosocial predictors of chronic postsurgical

increased preoperative
anxiety, an introverted personality, less catastrophizing, social support and solicitous responding in the week after amputation, higher emotional numbing scores at 6 and 12 months, fear of surgery, and “psychic vulnerability


Pain catastrophizing

relates to unrealistic beliefs that
the current situation will lead to the worst possible pain


Solicitous responding

refers to the behaviors on the
part of spouses or significant others who unwittingly
reinforce patients’ negative behaviors and thereby increase
their frequency of occurrence


Three main surgical factors have a possible influence on
the incidence of CPSP

Experience of the surgeon
Avoidance of intraoperative nerve injury.
Use of minimally invasive surgical techniques where possible


Many CPSP syndromes occur following
surgery around significant nerve structures Examples

pain after inguinal hernia repair (ilioinguinal and iliohypogastric nerves), axillary dissection (intercostobrachial nerve), and post-thoracotomy pain (intercostal nerves).


When a nerve is injured

it emits a long-lasting, high frequency burst of activity. This activity is transmitted to the central nervous system where the massive excitatory
stimulus activates postsynaptic NMDA receptors, leading to
excitotoxic destruction of inhibitory interneurons,18 disinhibition
of pain pathways, and increased postoperative pain


preoperative analgesia

would block central
sensitization caused by surgical insult and thus reduce
the severity of acute postoperative pain.


preventive analgesia

Preventive analgesia refers to the attempt block nociceptive input through the application of several analgesic agents acting at different sites (multimodal analgesia) starting prior to surgery and continuing for several hours or days following surgery. A successful
preventive analgesic intervention would reduce or ablate pain for hours, days, or weeks following surgery and well beyond the duration of action of the initial analgesic


NMDA receptor
antagonists in the prevention of pain following surgery

ketamine and dextromethorphan


gabapentin and pregabalin

bind to the a2d unit of
the calcium channel and are useful components of multimodal analgesia, producing opioid sparing effects and reducing the severity of acute postoperative pain


providing effective
acute pain control is best performed using

multimodal analgesic techniques, including local anesthetics, opioids, and other agents such as NMDA receptor antagonists and/ or gabapentin and associated drugs

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