Pain is one of the most challenging problem in medicine and biology: A challenge to the suffer --> learn live with pain. A challenge to the physician --> seeks every possible means to help the patient A challenge to the scientist --> who tries to understand the mechanism of terrible suffering. It is also a challenge to society --> find financial to relieve or prevent the pain and suffering.

1. What we know about pain?
(A Challenge Phenomena)
A. Husni Tanra
Department of Anesthesiology IC and Pain Management
Faculty of Medicine Hasanuddin University
Makassar

2. •“The more we study the
more we know that we
don’t know nothing”
Prof. Ch. Makaliwi 1970

3. Pain
Derived from greek
(poine) and latin (poena)
signify “ a penalty or
punishment”

4. Pain
• Pain occur due to tissue damage: damage due
to extreme mechanical, thermal or chemical
stimulation.
• Pain is a protective mechanism: person try to
remove the tissue damage. Is an alarm system.
• However, Chronic pain is not alarm anymore 
produce terrible suffering.
• Loss of pain perception can cause and increase
tissue damage  Congenital insensitivity to
pain.

6. Evolution and definition of pain :
From withdrawal reflexes  subjective experience
From a symptom of disease  disease entity
Accepted by IASP, with state:
(Merskey, 1979)
‘Pain is an unpleasant sensory and emotional
experience associated with actual or potential
tissue damage, or described in terms of such
damage

7. Noxious perception?
A number of theories:
1. Specificity theory by Descartes (16 Century)
3. Gate control theory by Melzack and Wall
(1965)
4. Sensitization theory by Woolf et al (1990)
Evolution of Pain perception.

8. Pain was
faithfully
transmitted
from
periphery to
brain
1. Specificity theory
Descartes
(17th Century)
Modified by AHT

9. 2.GATE CONTROL THEORY by MELZACK and Wall (1965)
P. Wall R. Melzack

11. 3.Sensitization theory by Woolf (1990)
 In normal situation two distinct sensory
nerve fibers
1. Low threshold Ab fiber carries
innocuous sensation.
2. High threshold Ad & C fiber carry brief pain.
 After tissue injuries and relies mediators 
peripheral and central Sensitization.
Hyperalgesia
Allodynia

12. Normal Situation
Innocuous
Sensation
Low intensity
Stimulation
High intensity
Stimulation
High
threshold A
 and c fiber
nociceptors
Brief Pain

13. After Tissue Damage
Low threshold
mechanorecept
or A
Sensitized
nociceptor A
and C fibers
Allodynia
Hyperalgesia
Pain
Low intensity
stimulation

14. Do we have centre of
pain perception?
Somato-Sensoric?

16. Does SS located in the cortex is the only pain
perception?
Fanctional Imagery
(Using f MRI )
Many hemispheric regions are
activated during noxious stimulation,
and particularly at the controlateral
level (orange areas).
http://www.hopkins-arthritis.som.jmhi.edu/rheumatoid
Indicate that not only prefrontal cortex
Is firing but almost all parts of the brain,
Include mid brain, and brain stem.
This tell us how important pain is, that
all part of the body should be informed.

17. Pain has multidimensional experience
1. sensory – discriminative (inderawi)
– Identifies the intensity, type and location of
pain (where is the injury)
2. Affective – motivational (kejiwaan)
– Assessing the injury the (meaning of injury)
3. Emotional – behavioral component (emosi)
– Attention, mood and behavioral due to pain
(what should I do for the injury)

18. Pain Classification
 Anatomy ( headache, LBP, pelvic pain)
 Disease ( Cancer pain, HIV pain)
 Location ( Central & Peripheral pain)
Duration
 Acute pain
 Chronic pain
Most accepted classification:
According to Pathophysiology
1 Nociceptive pain (Acute pain)
 Somatic pain
 Visceral pain
2. Neuropathic pain
3. Psychologic pain

19. Which one is the most understood?
Among all, nociceptive pain is the most understood form,
such as postoperative pain because:
• We know what causes it
• We know the mechanism
• We know how to treat it
• We know the best drugs or
method for it
• We know it is self limited
(Lema MJ, Department of Anesthesiology, Buffalo State University)

20. Why a Lot of patients suffering from
Chronic Pain After Surgery ?
• 5130 chronic pain patients
in 10 pain clinics in the UK
 post surgery: 22.5%
 post trauma: 18.7%
• So, about 2000 chronic pain patients, due to surgery
and trauma, in UK.
(Crombie et al. Pain Clin 1992; 5: 436-7)

21. Questions Regarding
Postoperative Pain
• Some patients complain Chronic Pain After
Surgery (CPAS) even with small incision (e.g.
laparoscopy)
• Some patients did not complain CPAS even
with large incision (e.g. thoracotomy)

22. Predisposing factors to
develope CPSP.
1. The type of surgery.
2. Postoperative pain intesity. (under-
treatment of postoperative pain).
3. Psychological factor.
4. Genetic factors.

23. Incidence of Chronic Pain After Surgery

24. Chronic post-surgical pain
1. After limb amputation
 The incidence of phantom
pain varies from 50% - 85%
 About 40% of amputees
having
severe phantom pain
 Prevalence of phantom pain
 After trauma was 12%
 Due to cancer was 48%

25. Phantom Limb Pain is a
‘Pain Memory’!
• In 57% of subjects with phantom pain, this
resembled preamputation pain
• “… somatosensory inputs of sufficient intensity
and duration can produce long-lasting changes in
central neural structures”
• Epidural anesthesia may reduce incidence but
cannot totally prevent it
Katz&Melzack, Pain 1990;43:319

26. Chronic post-surgical pain
2. After thoracic surgery
(thoracotomy)
• After thoracotomy is up 50%.
• Damage intercostal nerve is the
main cause.
• Sternotomy also showed similar
results, the incidence was 28 %
• Endoscopic surgery may not
able to prevent of CPSP
• This suggest a more complicated
aethiology

29. Chronic post-surgical pain
3. After breast surgery
Incidence of pain at one
or more these sites is
50 %
Damage to
intercostobrachial nerve is
considered the main
cause
Carpenter ‘s found only a
lumpectomy may
developed chronic pain

30. Chronic post-surgical pain
4. After herniorrhapy
 Incidence of chronic pain after hernia repair
was 0- 37%.
Cunningham* et al found that
 Pain at 12 months was 65%
 12% moderate to severe pain
 Incidence of chronic pain after
transperitoneal laparascopic
Herniorrhapy is 15 %
* Cunningham et al. Pain in the post-repair patient. Ann Surg 1999;224:598-602
Nerves in the inguinal area

31. Chronic post-surgical pain
5. After cholecystectomy
 Arround 40% of patients
complain pain after
cholecystectomy
 Incidence of chronic pain
varying from 3% -20%
 Laparascopic cholecystectomy
Incidence of chronic pain is
lower than open
cholecystectomy

32. Chronic post-surgical pain
6. After other surgeries
 Symphatectomy
 Total hip replacement 28% (Nikolajsen)
 Cardiac surgery
 Rectal amputation
 Vasectomy
 Histerectomy 14 % (Brandsborg)
 Cesarian Section 12% (Nikolajsen) Dental
extraction
 Dental extraction
 Etc.

34. Questions Regarding Visceral Pain

35. Sherrington’s Approach
Pain in general has been dominated by
Sherrington's approach
“ PAIN AS PHYSICAL ADJUNCT OF A PROTECTIVE REFLEX”
IT HAS A SURVIVAL VALUE
(Sherrington 1926)
However, pain of visceral origin shows a number
of clinical features that make it quite different or
do not validate Sherrington’s approach

36. Clinical Features of Visceral Pain
There is a poor correlation between amount of
visceral pathology than the level of distress and
pain intensity, e.g;
• Chronic pancreatitis, intensity of pain is not correlate
with Radiology & Lab. Finding.
• Irritable Bowel Synd, noncardiac chest pain, post
cholecystectomy synd.  limited activity without
abvious visceral pathology.
• On the other hand, colick due to ureter stone , shows
tremedous pain.

37. Questions Regarding Visceral Pain
• Visceral pain will appear when visceral stretched , but
not pain when incision
Appendicitis
• Small disturbances in visceral
cause tremendous pain
• Otherwise, it was great as
pancreatitis showed
Pancreatitis
• no significant symptoms,
although it was found that very
real change in the laboratory.
Example

38. Visceral pain can not be evoked from all
visceral.
Some Visceral organs such as:
 lungs
 liver
 kidneys
do not evoked any sensory feed- back, unless
adjacent structures are also affected.
It is difficult to understand , why such
important internal organs have no sensation.
Pain of supernatural origin, in western world.

39. – The mechanism is known as VISCERO-
SOMATIC CONVERGENCE.
– Visceral pain, generate “neurophysiologic
response” include motor and autonomic
reflex, called “pseudaffective reaction”.
– These pseudaffective reaction makes patients
looked more ill than pathological.
Referred pain and Autonomic reflex

40. Diverse Phenomenology
of Neuropathic Pain

41. Questions Regarding Neuropathic
Pain
Diverse Phenomenology
• Some patients report dysesthesia (“abnormal
discomfort or pain”)
– Burning, shooting, electrical
– After sensations
– Spontaneous or touch-evoked
• But some patients report familiar pain
(e.g. aching)

42. • Some patients report neurological phenomena
– Paresthesia (abnormal nonpainful sensations)
– Weakness, clumsiness
– Loss of sensation
– Focal autonomic dysregulation (swelling, skin
changes, sweating abnormalities)
• But some patients have pain alone
Questions Regarding Neuropathic
Pain
Diverse Phenomenology

43. •Some patients have neurological signs
– Allodynia, hyperalgesia
– Hyperpathia
– Other sensory abnormalities
– Weakness, incoordination, reflex asymmetries
– Focal autonomic or trophic changes
• But some patients have normal exams
Questions Regarding Neuropathic
Pain
Diverse Phenomenology

44. Relation Between etiology, mechanism &
symptom is very complex
1. One mechanism could be responsible for
many different symptoms.
2. The same symptom in two different
patients may be caused by different
mechanism
3. Finally, more than one mechanism can
operate in one patient & this
mechanism may change with time.

45. Relation Between etiology, mechanism &
symptom is very complex (cont.)
• Because of our inadequate knowledge in
mechanism of neuropathic pain
So, the aim of treatment therefore, is
often just to help patient cope by
means of psychological or
occupational therapy, rather than to
eliminate the pain.

46. Take home messages
Pain is one of the most challenging problem in
medicine and biology.
1. A challenge to the suffer  learn live with pain.
2. A challenge to the physician  seeks every
possible means to help the patient
3. A challenge to the scientist  who tries to
understand the mechanism of terrible suffering.
4.It is also a challenge to society  find financial
to relieve or prevent the pain and suffering.

47. •It is also a Challenge
of all of us, as
Anesthesiologists