Department of Anesthesiology
M.L.B. Medical College, Jhansi
CHRONIC PAIN MANAGEMENT
Co-ordinator- Dr. Chavi Sethi (MD)
Speaker- Dr. Sushil
• Pain is not just a sensory modality but is an experience.
• The International Association for the Study of Pain defines pain as
"an unpleasant sensory and emotional experience associated with
actual or potential tissue damage, or described in terms of such
• response to pain can be highly variable among persons as well as in
the same person at different times.
• term "nociception," which is derived from noci (Latin for harm or injury), is
used to describe the neural response only to traumatic or noxious stimuli.
All nociception produces pain, but not all pain results from nociception.
• Many patients experience pain in the absence of noxious stimuli. It is
therefore clinically useful to divide pain into one of two categories
(1) acute pain, which is primarily due to nociception, and
(2) chronic pain, which may be due to nociception but in which psychological
and behavioral factors often play a major role.
• Pain can also be classified according to pathophysiology (eg, nociceptive or
neuropathic pain), etiology (eg, postoperative or cancer pain), or the
affected area (eg, headache or low back pain). Such classifications are
useful in the selection of treatment modalities and drug therapy
• Chronic pain is defined as pain that persists beyond the usual course
of an acute disease or after a reasonable time for healing to occur;
this period can vary from 1 to 6 months.
• Chronic pain may be nociceptive, neuropathic, or mixed.
• Patients with chronic pain often have an attenuated or absent
neuroendocrine stress response and have prominent sleep and
affective (mood) disturbances, differentiate from acute pain
• A distinguishing feature is that psychological mechanisms or
environmental factors frequently play a major role.
most common forms of chronic pain include those associated with –
• musculoskeletal disorders,
• chronic visceral disorders,
• lesions of peripheral nerves, nerve roots, or dorsal root ganglia
(including diabetic neuropathy, causalgia, phantom limb pain, and
• lesions of the central nervous system (stroke, spinal cord injury, and
multiple sclerosis), and
• cancer pain.
The pain of most musculoskeletal disorders (eg, rheumatoid arthritis
and osteoarthritis) is primarily nociceptive, whereas pain associated
with peripheral or central neural disorders is primarily neuropathic
Mechanisms of Pain: Neuroplasticity
How does a Chronic Pain State Develop?
• Peripheral Sensitization
Injury causes release of
Reduction in threshold and
increase response of
• Central Sensitization
- Membrane excitability, synaptic
recruitment and decreased
- Uncoupling of pain from
Evaluating the Patient with Pain
physician must first distinguish between acute and chronic pain.
management of acute pain is primarily therapeutic, whereas that of chronic pain
additionally involves investigative measures.
The former requires only a pertinent history and examination, including
quantitative evaluation of pain severity, whereas the latter requires a careful
history and physical examination, a review of prior medical evaluations and
treatments, and thorough psychological and sociological evaluations.
physical examination should emphasize the musculoskeletal and neurological
Imaging studies are often necessary and may include plain radiographs, computed
tomography (CT), magnetic resonance imaging (MRI), or bone scans.
These studies can often detect unsuspected trauma, tumors, or metabolic bone
disease. MRI is particularly useful for soft tissue analysis and can show nerve
numerical rating scale, faces rating scale, visual analog scale (VAS), and the
McGill Pain Questionnaire (MPQ) are most commonly used.
Because chronic pain is so complex, there are often multiple treatment
chronic pain often is best managed using what is called a “multimodality”
approach. A multimodality approach to chronic pain includes a combination
of therapies selected from eight broad categories:
Complementary and Alternative medicine therapies
• Pharmacological interventions in pain management include COX inhibitors,
opioids, antidepressants, neuroleptic agents, anticonvulsants, corticosteroids, and
systemic administration of local anesthetics.
Antidepressants- These agents demonstrate an analgesic effect that occurs at a
dose lower than needed for their antidepressant action. Both actions are due to
blockade of presynaptic reuptake of serotonin, norepinephrine, or both.
• Older tricyclic agents appear to be more effective analgesics than selective
serotonin reuptake inhibitors (SSRIs).
• most useful in patients with neuropathic pain, eg, from postherpetic neuralgia
and diabetic neuropathy. They potentiate the action of opioids and frequently
normalize sleep patterns
nonselective norepinephrine/5-HT reuptake inhibitors (amitriptyline,
imipramine, clomipramine, venlafaxine),
preferential norepinephrine reuptake inhibitors (desipramine, nortriptyline
selective 5-HT reuptake inhibitors (citalopram, paroxetine, fluoxetine).
Anticonvulsants have been found to be extremely useful in patients with
neuropathic pain, particularly trigeminal neuralgia and diabetic neuropathy.
• These agents block voltage-gated sodium channels and can suppress the
spontaneous neural discharges that play a major role in these disorders.
• Gabapentin may offer additional unique beneficial effects. It has also been shown
to be an effective adjuvant for postoperative pain.
• The most commonly employed agents are phenytoin, carbamazepine, valproic acid,
clonazepam, and gabapentin . Lamotrigine and topiramate may also be effective.
All are highly protein bound and have relatively long half-lives.
• neuroleptics useful in patients with refractory neuropathic pain.
• The most commonly used agents are fluphenazine, haloperidol, chlorpromazine,
• Their therapeutic action appears to be due to blockade of dopaminergic receptors
in mesolimbic sites.
• Glucocorticoids are extensively used in pain management for their
antiinflammatory and possibly analgesic actions.
They may be given topically, orally, or parenterally (intravenously, subcutaneously,
intrabursally, intraarticularly, epidurally).
• Large doses or prolonged administration result in significant side effects.
• Excess glucocorticoid activity can produce hypertension, hyperglycemia, increased
susceptibility to infection, peptic ulcers, osteoporosis, aseptic necrosis of the
femoral head, proximal myopathy, cataracts, and, rarely, psychosis.
• Patients can also develop the physical features characteristic of Cushing's syndrome
Excess mineralocorticoid activity causes sodium retention and hypokalemia, and
can precipitate congestive heart failure.
• Dexamethasone, Betamethasone, Triamcinolone and Methyl-prednisolone are
Systemic Local Anesthetics
• Local anesthetics are occasionally used systemically in patients with neuropathic
• They produce sedation and central analgesia; the analgesia frequently outlasts
the pharmacokinetic profile of the local anesthetic and breaks the "pain cycle.
• " Lidocaine, procaine, and chloroprocaine are the most commonly used agents.
• They are given either as a slow bolus or by continuous infusion. Lidocaine is given
by infusion over 5–30 min for a total of 1–5 mg/kg.
• Procaine 200–400 mg can be given intravenously over the course of 1–2 h,
whereas chloroprocaine (1% solution) is infused at a rate of 1 mg/kg/min for a
total of 10–20 mg/kg.
• Monitoring should include the electrocardiogram (ECG), blood pressure,
respirations, and mental status; full resuscitation equipment should also be
immediately available. Signs of toxicity such as tinnitus, slurring, excessive
sedation, or nystagmus necessitate slowing or discontinuing the infusion.
• The primary effect of 2-adrenergic agonists is activation of descending inhibitory
pathways in the dorsal horn. Epidural and intrathecal 2-adrenergic agonists are
particularly effective in neuropathic pain and opioid tolerance.
• Clonidine is most commonly used drug in this grup.
• Botulinum toxin injections have been increasingly utilized in the treatment of
painful conditions associated with skeletal muscle.
• use in the treatment of conditions associated with involuntary muscle contraction
(eg, focal dystonia and spasticity).
• Some clinicians have used the drug in the management of headaches and
• Botulinum toxin blocks acetylcholine released at the synapse in motor nerve
endings but not sensory nerve fibers. Proposed mechanisms of analgesia include
improved local blood flow, relief of muscle spasms, and release of muscular
compression of nerve fibers
The topical application of various analgesics is an area of considerable interest because
many chronic pain syndromes depend to some degree on the peripheral activation of
primary afferent neurons.
• Localized administration can potentially optimize drug concentrations at the site of pain
generation while avoiding high plasma levels, systemic side effects, drug interactions,
and the need to titrate doses into a therapeutic range.
• topical NSAIDs, tricyclic antidepressants, capsaicin, local anesthetics, and opioids are
topical tricyclic antidepressant (doxepin) has shown efficacy in a mixed group of patients
with neuropathic pain and, as a mouthwash, in patients with chemotherapy-induced
Capsaicin is the active pungent ingredient in chili peppers.
• Capsaicin is available as 0.025% and 0.075% cream. It was shown to achieve pain relief
in patients with postherpetic neuralgia, postmastectomy syndrome, osteoarthritis, and
a variety of neuropathic syndromes.
Topical formulations of local anesthetics block Na+ channels in primary afferent neurons
• lidocaine patches and gels showed pain reduction in patients with postherpetic
neuralgia and allodynia.
• patients with painful diabetic polyneuropathy, CRPS, postmastectomy syndrome, or
post-thoracotomy syndrome can achieve relief of pain.
Topically applied or locally injected opioids produce analgesia by activating opioid
receptors on primary afferent neurons.
• This leads to inhibition of Ca2+, Na+, and TRPV1 currents, which are activated by
• Intra-articular morphine also produces analgesia in chronic rheumatoid and
osteoarthritis, where its potency was shown to be similar to standard intraarticular steroids and long lasting (up to 7 days), possibly because of morphine's
• opioids have been applied locally (e.g., in gels) to treat pain from skin ulcers,
cystitis, cancer-related oral mucositis, corneal abrasion, and bone injury
Topical Opioids Provide Temporary Relief in Central Intractable Pain.
Treatment consisted of one or more of the following agents in a range of strengths
dissolved in 1oz of cold cream: morphine 30–90mg; oxycodone 30–90mg;
hydromorphone 8–24mg, or carisoprodol 350–1,050mg. Patients were instructed
to use their topical preparations in a manner to maximize pain relief.
Nonsteroidal Anti-inflammatory Drugs and
• The acidic NSAIDs and the nonacidic antipyretic analgesics (e.g., acetaminophen,
phenazones) inhibit COXs, enzymes that catalyze the transformation of
arachidonic acid (a ubiquitous cell component generated from phospholipids) to
prostaglandins and thromboxanes.
• Less severe pain states (e.g., early arthritis, headache) are commonly treated
with nonselective NSAIDs (e.g., aspirin, ibuprofen, indomethacin, diclofenac) or
antipyretic analgesics (e.g., acetaminophen), mostly used orally.
• Some agents are available for parenteral, rectal, or topical application
Pain management by rehabilitative
Physical therapy (PT)-useful in teaching patients to controlpain, to move in
safe and structurally correct ways, to improve range of motion, and to increase
flexibility, strength and endurance.
• “Active” and “Passive” modalities can both be used, but active modalities, such as
therapeutic exercise,are particularly important when the goal is to improve both
comfort and function.
Bed rest - use of prolonged bed rest in the treatment of patients with neck and
low back pain.
• For severe radicular symptoms, limited bed rest of less than 48 hours may be
beneficial to allow for reduction of significant muscle spasm brought on with
Bracing- acute neck pain secondary to whiplash injury,
Manipulation & mobilisation- treatment of patients with acute low
Transcutaneous electrical nerve stimulationhas been used to treat patients with various pain conditions,including neck
and low back pain
• TENS is generally used in chronic pain conditions and not indicated in the
initial management of acute cervical or lumbar spine pain.
Thermal modalities- Thermal modalities include a variety of methods that
produce heating and cooling of the tissues to manage acute and chronic
• Superficial heat, such as moist hot packs, increases skin and joint
temperature and blood flow, and may decrease joint stiffness and muscle
Diathermy- Diathermy involves the use of high-frequency oscillating current
and ultrasound (inaudible sound wave vibrations) to create deep heating.
• The deep heating may reduce the perception of pain.
Ultrasound- Ultrasound is a deep-heating modality that is most effective in
heating structures such as the hip joint, which superficial heat cannot reach
• It has been found to be helpful in improving the distensibility of connective tissue
which facilitates stretching.
• It is perhaps best used in the region of the upper trapezius or lumbar paraspinals to
facilitate active stretching and strengthening.
Cryotherapy - Cryotherapy can be achieved through the use of ice, ice packs, or
continuously via adjustable cuffs attached to cold water dispensers Intramuscular
temperatures can be reduced by between 3 °C and 7 °C, which functions to reduce
local metabolism, inflammation, and pain.
• Cryotherapy works by decreasing nerve conduction velocity, termed cold-induced
neuropraxia, along pain fibers with a reduction of the muscle spindle activity
responsible for mediating local muscle tone.
Psychological/Mind-Body therapies for chronic pain
• Psychological factors are important contributors to the intensity of pain and to
the disability associated with chronic pain.
• Pain and stress are intimately related. There may be a vicious cycle in which pain
causes stress, and stress, in turn, causes more pain
• Mind/body approaches address these issues and provide a variety of benefits,
including a greater sense of control, improved coping skills, decreased pain
intensity and distress, changes in the way.
Cognitive-Behavioral therapy - CBT has proven to be effective in reducing pain
and disability when it is used as part of a therapeutic strategy for chronic pain.
• It can provide educational information and diffuse feelings of fear and
• CBT may include training in various types of relaxation approaches, which can
help people in chronic pain lower their overall level of arousal, decrease muscle
tension, control distress, and decrease pain, depression and disability.
Biofeedback- Biofeedback is the use of electronic monitoring instruments to provide
patients with immediate feedback on heart rate, blood pressure, muscle tension, or
brain wave activity.
• This allows the patient to learn how to influence these bodily responses through
conscious control and regulation.
• Biofeedback has been shown to be effective in the management of migraine
headaches, fibromyalgia, temporomandibular disorders, and rheumatoid arthritis,
Raynaud’s disease, tension headaches, headaches in children and the pain
associated with irritable bowel syndrome.
Spinal Cord Stimulation (SCS)- This technique is also called dorsal column
stimulation because it was thought to produce analgesia by directly stimulating
large A fibers in the dorsal columns of the spinal cord. Proposed mechanisms
include activation of descending modulating systems and inhibition of
• Spinal cord stimulation is most effective for neuropathic pain.
• Accepted indications include sympathetically mediated pain, spinal cord lesions
with localized segmental pain, phantom limb pain, ischemic lower extremity pain
due to peripheral vascular disease, and adhesive arachnoiditis.
• Patients with failed back surgery syndrome (FBSS), which is typically a mixed
nociceptive–neuropathic disorder, also appear to benefit from SCS.
Deep brain stimulation
used for intractable cancer pain, and rarely for intractable neuropathic pain of
• Electrodes are implanted stereotactically into the periaqueductal and
periventricular gray areas for nociceptive pain (primarily cancer and chronic low
back pain); for neuropathic pain, the electrodes are implanted into specific sensory
• The most serious complications are intracranial hemorrhage and infection
Interventional Methods Used for Chronic Pain
• Interventional pain management or interventional pain medicine is a subspecialty
of the medical specialty - pain management, devoted to diagnosis & treatment of
pain & related disorders by application of interventional techniques in managing
subacute , chronic, persistent & intractable pain independently or in conjuction with
other modalities of treatment.
• It fills the gap between pharmacological management of pain and more invasive
1) Diagnostic & Therapeutic Neural Blockade- Neural blockade with
local anesthetics can be useful in delineating pain mechanisms, but, more
importantly, it plays a major role in the management of patients with acute or
chronic pain .
Selection of the type of block depends on the location of pain, its presumed
mechanism, and the skills of the treating physician.
Local anesthetic may be applied locally (infiltration), or at a peripheral nerve,
somatic plexus, sympathetic ganglia, or nerve root. It can be applied centrally in
the neuraxis(Spinal and epidural)
A )Somatic Blocks Trigeminal Nerve Blocks- The two principal indications are trigeminal neuralgia
and intractable cancer pain in the face
• these blocks may be performed on the gasserian ganglion
Facial Nerve Block- Blockade of the facial nerve is occasionally indicated
to relieve spastic contraction of the facial muscles and to treat herpes zoster
affecting this nerve.
Glossopharyngeal Block- Glossopharyngeal nerve block may be used for
patients with pain due to malignant growths at the base of the tongue, the
epiglottis, and palatine tonsils. It can also be used to distinguish glossopharyngeal
neuralgia from trigeminal and geniculate neuralgia
Occipital Nerve Block- Occipital nerve block is useful diagnostically and
therapeutically in patients with occipital headaches and neuralgias.
Phrenic Nerve Block- Blockade of the phrenic nerve may occasionally provide
relief for pain arising from the central portion of the diaphragm. It can also be
useful in patients with refractory hiccups (singultation
Suprascapular Nerve Block -This block is useful for painful conditions arising
from the shoulder (most commonly arthritis and bursitis.
Cervical Paravertebral Nerve Block- Selective paravertebral blockade at the
cervical level can be useful diagnostically and therapeutically for cancer patients
with pain originating from the cervical spine or the shoulder.
Lumbar Paravertebral Somatic Nerve Block- Paravertebral block at this
level is useful in evaluating pain due to disorders involving the lumbar spine or
Lumbar Medial Branch & Facet Blocks- These blocks may establish the
contribution of lumbar facet (zygapophyseal) joint disease in back pain.
Corticosteroids are commonly injected with the local anesthetic when the
intraarticular technique is chosen.
2)Sympathetic Blocks- Sympathetic blockade can be accomplished by a variety of
techniques including subarachnoid, epidural, as well as paravertebral blocks.
• Unfortunately, these approaches usually block both somatic and sympathetic
• most common indications include reflex sympathetic dystrophy, visceral pain, acute
herpetic neuralgia, postherpetic pain, and peripheral vascular disease.
StellateBlock- used in patients with head, neck, arm, and upper chest pain.
Thoracic Sympathetic Chain Block –
Celiac Plexus Block- indicated in patients with pain arising from the abdominal
viscera, particularly abdominal malignant growths.
Splanchnic Nerve Block-
Neurolytics- Neurolytics employ injection of chemical agents such as alcohol,
phenol, or glycerol to block pain messages.
It is indicated for patients with limited life expectancy and patients who have
recurrent or intractable pain after a series of analgesic blocks.
Potential side effects of neurolytic agents include neuritis and deafferentation
pain, motor deﬁcit and unintentional damage to non-targeted tissue.
Ethyl alcohol,phenol, glycerol, Hypertonic or hypotonic saline , Ammonium salts
,Botulinum neurotoxins are commonly used neurolytics,
• Radiofrequency ablation
– High frequencies of 300–500 KHz are used
– A modern RF lesion generator has the following functions:
■ Continuous on-line impedance measurement
■ A nerve stimulator
■ Monitoring of voltage, current, and wattage during the RF procedure
■ Temperature monitoring
■ Pulsed current delivery mode
– Continuous Radio Frequency Lesioning
• The voltage of the generator is set up between the electrode and the
ground plate. The body tissues complete the circuit and RF-current ﬂows
through the tissue, resulting in an electric ﬁeld.
• Frictional dissipation of the ionic current within the ﬂuid medium causes
tissue heating. RF heat is therefore generated in the tissue, and the
electrode is heated by the tissue.
• The size of the lesion depends on the tip temperature and the tip
temperature depends on the power deposition.
• But there are other factors involved as well. Heat is also removed from
the lesion area by conductive heat loss and blood circulation. This is
referred to as heat “washout.”
• Maximum “volume” of a lesion is effectively obtained after 40 seconds,
and that the lesion size strongly depends on tip temperature and on
Indications of RF neuroablation
• Radiofrequency neuroablation is frequently carried out for
following conditions :
• - Lumbar RF sympathectomy for peripheral vascular disorders and
complex regional pain syndrome (CRPS) of lower extremity
• - RF ablation of Gasserian Ganglion or of individual branches for
• - Cervical, thoracic, lumbar facet joint RF denervation
• - Stellate ganglion lesioning for CRPS of upper extremity
• - Cervical thoracic lumbar, sacral rhizolysis
• - Sacroiliac joint denervation
• - Intervertebral disc annuloplasty in intervertebral disc
– A technique in which the application of low temperatures produced by
cryosurgical equipment achieves anesthesia or analgesia by blocking
peripheral nerves or destroying nerve endings.
– Expansion of gas enclosed in the cryoprobe results in Kelvin effects; that is,
gas under pressure escaping through a small oriﬁce expands and cools,
achieving temperatures between -500C & -700C at the tip, and returns
through an inner tube.
– For myelinated ﬁbers, a direct lesion 3 mm in diameter with a freeze time of
1 minute produces a conduction block.
– Where the nerve is frozen amid other tissues, the duration of exposure
should be approximately 90 to 120 seconds.
– A prolonged conduction block occurs when the nerve is frozen at
temperatures between -5 C and -20 C. This causes axonal disintegration and
breakdown of myelin sheaths.
– Wallerian degeneration occurs with the perineurium and epineurium
– The absence of external damage to the nerve and the minimal inﬂammatory
reaction following freezing ensure that regeneration is accurate and
• Intrathecal Drug Delivery Systems
– In general, chronic intraspinal infusion therapy using implantable drug
administration systems has been reserved for patients whose condition is
considered chronic, and have failed more conservative therapies.
– Patients must have either inadequate pain control or intolerable side effects
on systemic opiates and adjuvant therapy.
– General guidelines for considering intrathecal therapy include an expected
– Although percutaneous externalized epidural or even intrathecal catheter
placement is feasible for short-term treatment, vulnerability to infection and
economic considerations preclude serious considerations for long-term use
– It is a minimally invasive procedure that is effective in the treatment of pain
resulting from pathologic compression fractures, osteolytic bone lesions,
myelomas, hemangiomas and osteoporosis.
– The main indication is the symptomatic (painful) osteoporotic compression
fracture of the thoracolumbar spine.
– It is essential to discriminate an acute event with sudden onset of pain and
plain x-rays showing radiological signs of an acute fracture from chronic
painful disorders of the spine.
• Balloon Kyphoplasty
– The indications for balloon kyphoplasty are the same as in vertebroplasty.
– It is especially indicated in the presence of vertebral body deformity.
• General contraindications include uncorrectable coagulation disorders,
infectious processes of the spine, and allergies against PMMA or contrast
medium. Poor pulmonary status and difﬁculty lying prone are relative
• Ozone Nucleolysis
– Ozone nucleolysis may be done in most kinds of disc related pain.
• degenerated disc without any prolapse and nerve root irritation.
• contained disc prolapse or disc bulge with root irritation.
• non-contained disc.
– 3-10 cc of oxygen-ozone mixture (at a concentration of 29-40 microgram/ml)
is injected into the disc.
– There are few conditions when ozone therapy should not be performed.
They are active bleeding from any site, pregnancy, G6PD deficiency, active
hyperthyroidism, loss of control of urination & defecation, and progressive
sensory & motor loss.
– Complications of ozone therapy are very rare. They include post-procedural
muscle spasm & burning pain & discitis.
• Cancer pain can be managed with oral analgesics in most patients.
• The World Health Organization recommends a three-step approach
Pain persisting or
Non‐narcotic – “around the clock” 2
• Acetaminophen 650mg q4h or
• ASA 650mg q4h or
• Ibuprofen 400mg q4h or
• other NSAIDs
• +/- Adjuvants*
* Adjuvant therapy ‐ medications that can help to enhance the effects of non‐opioid and
1) NSAIDs (non‐steroidal anti‐inflammatories) ‐ can be used as co‐analgesics and are useful in
2) Tricyclic anti‐depressants ‐ Nortriptyline, Desipramine, and Amitriptyline are options,
although Amitriptyline can cause confusion
in the elderly. Studies have confirmed their effectiveness in treating diabetic neuropathy and
neuropathic pain from other sources
3) Anticonvulsant medications – Gabapentin, Pregabalin, and Carbamazepine can relieve the
shooting, electrical pains of peripheral
Add Opioid for Moderate Pain – “around the clock” 2
• Acetaminophen 325mg + codeine 30mg q4h (Tylenol #3) or
• Acetaminophen 325mg + codeine 60mg q4h (Tylenol #4) or
• Acetaminophen 325/500mg + oxycodone 5mg q4h (Percocet /
• +/- Adjuvants*
Note: Consider stronger opioid if pain not controlled by these
combinations at a total daily dose if 400mg/day of codeine or
Start strong oral opioid – “around the clock”ii
• Morphine 5‐10mg q4h titrate to pain
• Dilaudid 1‐4 mg q4h titrate to pain (hydromorphone
• MS‐Contin or other long acting 30‐60mg q8‐12 h
• Fentanyl 25ųg/ hour plus Morphine Sulphate 5 mg. q 2
hours for breakthrough – *never to be administered to
opioid naive clients
• +/- Adjuvants*
Notes: Use short acting preparation of same medication
increasing for breakthrough pain. Consider lower dose in opioid
and elderly patients