Chapter 52 Postamputation Pain Flashcards
Amputation of a limb can lead to painful and nonpainful
sequelae such as
phantom sensations, telescoping, residual
limb (aka “stump”) pain, and phantom pain
Reasons for Amputation
Vascular disease is responsible for approximately 77% of
major limb amputations, while trauma (21%) and cancer (2%) are less frequent causes. Among upper extremity amputees, trauma is the leading cause.
Phantom sensations
by definition nonpainful physical perceptions that occur after a traumatic or surgical amputation
that is perceived as emanating from the missing body part
Phantom sensations are common after
surgery,
with an incidence of 90% during the first 6 months.
A third of patients experience phantom sensations within
24 hr after their surgery
Is Excision of a body part essential for phantom sensations?
Excision of a body part,
is not essential for phantom sensations
Nonpainful phantom sensation may have various manifestations
including
kinetic sensations, and kinesthetic and
exteroceptive perceptions.
Kinetic sensations are exemplified by
perception of movements in the amputated body region, such as flexion/extension of the toes
Kinesthetic
perceptions are characterized by
distorted representations
in size or position of the missing body part (e.g., feeling
that the hand or foot is twisted).
Exteroceptive perceptions can include
paresthesias, tingling, touch, pressure,
itching, heat, cold, and wetness
Phantom sensations are commonly experienced
the distal portion of the limbs—hands and feet—possibly due to the rich innervation of these regions and the disproportionately large cortical representation of these regions in the homunculus.
TELESCOPING
the perception of progressive shortening
of the phantom body part resulting in the sensation that
the distal part of the limb is becoming more proximal
PHANTOM PAIN
the perception of a painful, unpleasant
sensation in the distribution of the missing or deafferentated body part.
Phantom pain can vary in character, duration, frequency, and
intensity
It can present as sharp, dull, burning, squeezing,
cramping, shooting, or as a shock-like electrical sensation. Patients may occasionally complain of intermittent tremors or painful muscle spasms in the stump associated with paroxysms of phantom pain.
phantom pain often changed in presentation
within the first 6 months after amputation
The characteristic
of the phantom pain changed from a mainly
exteroceptive-like pain (knife-like or sticking), localized in the entire limb or at least involving proximal parts of
the lost limb, to a mainly proprioceptive type of pain (squeezing or burning) localized in the distal parts of the amputated limb
One factor that increases the incidence of
phantom pain after amputation is
the presence of pain in
the limb before the amputation
Stump pain or residual limb pain
pain localized to the
residual body part following amputation.
Stump pain
is often secondary to
local pathologic processes such as infection; lesions of the skin, soft tissue, or bone; heterotopic ossification (.50% in traumatic amputations); and local ischemia
Stump pain is often secondary to local pathologic processes
These processes can generally be classified into the following categories: postsurgical
nociceptive, neurogenic, prosthogenic, arthrogenic, ischemic,
referred (usually from the spine or joints), sympathetically
maintained, or abnormal stump tissue (e.g., adhesive scar tissue)
Stump pain can be localized to
superficial (localized to the scar region of the incision), felt deep in
the distal stump, or encompass the whole residual limb.
Stump pain can frequently be differentiated from phantom pain based on
the fact that it is classically provoked
or exacerbated by traction or pressure, which often occurs during the use of a prosthesis.
The management
of stump pain entails a
detailed history and physical exam that includes ensuring a proper fitting prosthesis
Arthrogenic and referred stump pains are usually secondary
to
abnormal gait and asymmetrically distributed weight bearing, resulting in excessive stress on adjacent joints and/or lumbosacral spine structures. This can
lead to bursitis, accelerated arthritis, sacroiliac joint disease,
discogenic and facetogenic pain, and lumbosacral
radiculopathy.
PHANTOM PHENOMENA AFTER
MASTECTOMY
Most of these phantom sensations are felt intermittently,
occurring once every 2 or 4 weeks. phantom pain is localized in the entire breast or around
the nipple
PHANTOM PHENOMENA AFTER
MASTECTOMY
The onset of phantom sensation and/or pain almost always occurs within
3 months of surgery, with most cases occurring within 1 month.
the only way to distinguish between true “phantom” pain and other sources of postmastectomy pain (e.g., intercostal brachial
neuralgia, neuroma) may be via
a detailed history and
physical exam
suggest
that phantom phenomena are the result of
interactions xbetween altered peripheral, spinal, and supraspinal mechanisms.
Peripheral nerve damage during an
amputation initiates
axonal regeneration, resulting in a
neuroma.
A positive Tinel’s sign
(tapping on the injured
nerve or neuroma leading to pain in the phantom limb or
stump) represents a classic feature on physical examination
Afferent fibers in a neuroma develop
ectopic activity,
mechanical sensitivity, and chemosensitivity to catecholamines.
ion channels regulation in phantom limp
Upregulation of voltage-sensitive sodium channels, downregulation of potassium channels, and expression of novel receptors in the neuroma alter the excitability of the affected neurons and increase afferent input.
Injured neurons
can generate new, nonfunctional connections (ephaptic
cross-talk), resulting in
increased afferent input to the spinal cord. These changes may lead to spontaneous
pain, and explain the amplification in pain caused by emotional distress and/or exposure to cold that leads to increased sympathetic discharge and circulating catecholamines
Treatment of of phantom pain
Total spinal anesthesia, cordotomy, cordectomy,
and spinal cord stimulation have at best yielded only modest
relief of phantom pain; in some cases spinal anesthesia
can precipitate the development or rekindling of phantom
pain that previously subsided
Peripheral nerve injury leads to
deafferentation—
removal of afferent input to the dorsal column of the spinal cord—causing structural, neurochemical, and physiologic changes in central nervous system neurons. These changes result in functional alterations—plasticity—in
central neurons that lead to spontaneous pain signals which are transmitted centrally
Peripheral sensory input
at the level of the spinal cord also has inhibitory effects on the central transmission of pain.
Changes in the dorsal horn and the loss of afferent input lead to decreased impulses
from brainstem reticular areas, which normally exert
inhibitory effects on sensory transmission.
the absence of inhibitory effects of sensory input from the missing peripheral body part causes
increased autonomous
activity of dorsal horn neurons, in effect becoming “sensory
epileptic discharges”.
The brain exhibits neuroplastic changes both in motor
and sensory cortices
Cortical representation can be altered so that painful and nonpainful sensations in the phantom are a perceptual correlate of reorganizational processes in the somatosensory cortex
The first step in the management of stump pain is to
identify a specific etiology for the pain that can be the target for developing treatment strategy. The stump should be
carefully examined for a localized tender spot where a Tinel’s sign can be elicited suggestive of a neuroma. The
stump should also be examined for ulcers, potential sites of inflammation or bony abnormalities, evidence of ischemia, or recurrence in the case of malignancy.
changes in
gait and altered body mechanics may result in
musculoskeletal
pain. Rehabilitation therapy to correct gait and postural compensations that result in arthritic or referred pain may be useful
TENS
may be beneficial in 25% to
50% of patients with stump pain
Medication management
will depend on
whether the pain is suspected to be of somatic or neuropathic origin. In the former case, (NSAIDs), (COX-2)
antagonists, and/or opioids may be indicated. Neuropathic
pain resulting from neuromas should be treated with adjuvant
analgesics such as tricyclic antidepressants (e.g., nortriptyline)
and anticonvulsants (e.g., gabapentin).
Surgical therapies are indicated only when
a specific rectifiable pathology is identified. Protruding bone, bony
exostosis, wound infection, and poorly healed wounds are
clear indications for surgery.
A neuroma under constant
pressure or near a joint resulting in
repeated traction may
be treated by excision of the neuroma and repositioning
the nerve ending in bone or muscle
Selective nerve blocks of peripheral nerves may be useful as a
prognostic indicator of the success of excision
of the neuroma
Dorsal root entry zone (DREZ) lesioning
has not been effective in patients with isolated
stump pain.
initiated in the preamputation phase
In the case of surgical amputations, educating and counseling
the patient on the consequences of amputation, the
rehabilitation process, and the prosthetic options
Numerous treatment
approaches have been attempted for phantom pain
a wide variety of medications, physical
therapy, psychological interventions such as cognitive behavioral
therapies, complementary and alternative therapies,
neurostimulation, and ablative procedures at various sites in the peripheral and central nervous systems.
shown
to reduce phantom pain in the short term.
opioids, calcitonin, and ketamine
First-line medication classes for the treatment of neuropathic pain
include
gabapentinoid anticonvulsants and antidepressants
employed as add-on or individual therapy when first line treatment is ineffective
beta-blockers, neuroleptic agents, mexiletine, and capsaicin
Treatment for cramping pain, stump movement disorders, or flexor spasticity
baclofen or clonazepam may be effective
Opioid therapy
has been shown to provide
short-term relief of stump and phantom pains
offer temporary relief with
no proven meaningful long-term benefits
Various physical modalities such as ultrasound, vibration,
TENS, and acupuncture. These therapies
rely on the gate control theory of pain transmission, which proposes that stimulation of large nerve fibers “closes the gate” and inhibits the transmission of pain
centrally
Surgical interventions have not been shown to be of
significant benefit in phantom pain
Spinal cord stimulation
has been recommended to replace the loss of afferent input to the dorsal column and enhance the descending
inhibition of pain transmission.
Psychological interventions for phantom pain include
hypnosis, biofeedback, cognitive and behavioral therapies,
and support groups. These interventions may facilitate
adaptation to a change in body image, adaptation
to chronic pain, and relief of grief and anger
Mirror therapy
has been successfully used to alleviate phantom pain by exploiting the brain’s predilection for prioritizing visual stimuli over proprioceptive and somatosensory
input
Mirror therapy approach
It involves strategically placing a mirror adjacent to the intact limb to give the illusion that the missing body part is present and can be purposefully moved. Because sensory experiences can be evoked by visual stimuli,
mirror therapy increases spinal motor and cortical excitability
Educational efforts, usually done in conjunction with
psychological preparation, can also be beneficial when utilized in the
pre-amputation and postamputation periods.
These include early introduction and education regarding
the use of a prosthesis, information on the care and treatment
of the stump, and explanation of the rehabilitation process, which might include vocational retraining
the optimal
treatment of postamputation pain entails a multimodal
approach that includes
possible preemptive analgesia, psychotherapy,
education and rehabilitation, polypharmacy,
and if indicated, procedural interventions.
