pain management

1. Intervention Pain
Management on Treating
Postherpetic Neuralgia
Rivan Danuaji
Head of Neurology Department
Dr Moewardi Hospital/Medical Faculty of Universitas Sebelas Maret Surakarta
September 4th, 2021

2. Introduction
• Post herpetic neuralgia (PHN) is one of the most resistant chronic pain problems, commonly
affecting elderly patients.
• It presents as a pain that persists after the resolution of the rash caused by herpes zoster (HZ).
• Postherpetic neuralgia is defined as the occurrence of chronic, persistent, debilitating pain
with dermatomal distribution in patients who have recovered from shingles (Shiang Lin, et.al,
2019)
• Characteristic of PHN:
• aching, itchy, lancinating, or sharp
• allodynia, hyperalgesia,
• areas of anesthesia, and deficits in thermal, tactile, pinprick, or vibration sensations
• within or extending beyond the margins of the affected dermatomes

3. Introduction
• At 3months after the onset of shingles:
• Patients aged < 60 years have a 1.8% risk of postherpetic neuralgia,
• Patients aged > 60 years have risks of 3.3% (after 12 months).
• Despite the low probability, however, severe postherpetic neuralgia is considered
intolerable by the affected patients
• Postherpetic neuralgia is initially treated with medication à first line and second line
treatment option
• However, patients who experience persistent pain despite conservative treatment may
benefit greatly from interventional therapies

4. Treatment
Plan for Post-
Herpetic
Neuralgia
Singh, et al.: Post-Herpetic Neuralgia
Indian Journal of Pain | January-April 2013 | Vol 27 | Issue 1

5. PHN Mechanism

6. Pain
Intervention
for PNH
• IT injection of methylprednisolone
• Epidural injection of methylprednisolone
• Spinal Cord Stimulation
• rTMS
Central:
• Subcutaneous botulinum toxin A injection
• Local triamcinolone injection
• TENS
• Stellate ganglion block
• Paravertebral block
• DRG destruction
• Pulsed radiofrequency (DRG)
• Pulsed radiofrequency (intercostal nerves)
Peripheral

7. Intrathecal Injection of
Methylprednisolone
• Histopathologic studies of patients with PHN have
revealed subacute or chronic inflammatory processes
involving the infiltration and accumulation of
lymphocytes around the spinal cord
• PHN patients have relatively higher interleukin-8 (IL-
8) concentrations in the CSF
• A possible anti-inflammatory role for
methylprednisolone IT is the ability reduce the IL-8
concentration

8. The evidence:
Intrathecal Injection
of
Methylprednisolone
• IT MP reduced pain by >
50% in most patients at
either 4 or 24 weeks after
injection
• Significant reduce pain for
2 years

9. Epidural Injection
of MP
• Interlaminar to transforaminal
epidural steroid injection (ESI)
approach
• In transforaminal approach, drug
is deposited close to the site of
inflammation of the targeted
DRG and spinal nerve, thereby
possibly providing the greatest
potential for benefit with limited
systemic impact
• Use MP 60mg and lidocaine
injected to epidural space or
near DRG

10. Epidural Injection of MP

11. Spinal Cord Stimulation
• The mechanism of spinal cord
stimulation remains uncertain, The
“gate control theory of pain”
suggests that neural signal
transmission is regulated by the
dorsal horn of the spinal cord,
where A-beta fibers inhibit the
transmission of pain signals carried
by C-fibers
• Spinal cord stimulation may also
affect the levels of γ-aminobutyric
acid (GABA) and adenosine in the
dorsal horn and consequently
reduce neuropathic pain

12. Spinal Cord
Stimulation
• 3 studies reported
significant reductions in
postherpetic neuralgia
following spinal cord
stimulation
• By contrast, patients with
marked sensory loss and
those experiencing
constant pain without
allodynia would not
benefit from spinal cord
stimulation, as
deafferentation and
degeneration of the dorsal
column might be the
dominant mechanism

13. rTMS: 5Hz and 10 Hz
• Clinical practice has demonstrated that TMS applies not only to cranial stimulation, but
also to the simulation of peripheral nerves and muscles
• rTMS at 5 Hz and 10 Hz is effective in improving pain, sleep quality, and anxiety of patients
with PHN (Shalaby N et.al, 2016)
• Qian Pei et.al (2019) à RCT rTMS plus peripheral nerve block and standar medication.
• 60 patients with dx PHN à devide into 3 groups: ST + Sham rTMS, ST + 5Hz rTMS,
ST+10 Hz rTMS
• rTMS protocol: Intencity:80% MT, total number of stimulation 1500, location: M1 on
healthy side, duration: 17,5 minutes, 15 days (3 weeks)
• Follow up 1 months, 3 months
(Qian Pei et.al; Pain Physician 2019; 22:E303-E313 • ISSN 2150-1149)

14. Result
VAS reduction at different time points in the 3 groups Changes in QOL scores in the 3 groups
(T0: start treatment; T12: 12 weeks after rTMS)
(Qian Pei et.al; Pain Physician 2019; 22:E303-E313 • ISSN 2150-1149)

15. Peripheral

16. Subcutaneous Botulinum Toxin
A Injection
• Botulinum toxin is a neurotoxic protein purified
from the bacterium Clostridium botulinum
• Botulinum toxin reduces peripheral nociceptive
input by inhibiting the release of glutamate, a
peripheral neurotransmitter involved in
neurogenic inflammation.
• Botulinum toxin was injected subcutaneously
within a 1- to 2-cm radius over the painful region,
and the maximum doses did not exceed 200 and
100 IU

17. Subcutaneous Botulinum Toxin A Injection
• The observed benefits in both
studies included improved VAS
scores and sleep durations and
reduced numbers of patients
using opioids
• These effects emerged at 7 days
after injection and persisted for
3 months
• NNT of 1.2 for a 50% reduction
in the VAS score
• Smaller than conservative
medical treatments

18. Local Triamcinolone Injection
• Peripheral sensitization, which involves neural
damage and inflammation with subsequent
edema consequent to varicella zoster virus
reactivation, is among the mechanisms underlying
the development of postherpetic neuralgia
• the injured tissue releases inflammatory
mediators that reduce the nociception threshold,
and thus activate peripheral nociceptors
• Corticosteroids may ameliorate postherpetic
neuralgia by modulating this inflammatory
process

19. Local Triamcinolone Injection
• Patients received 3 injections at 2-week intervals and reported pain relief
at weeks 6 and 12
• There were some refractory events occur

20. Transcutaneous Electrical Nerve Stimulation (TENS)
• TENS is a noninvasive and safe
application of electrical stimulation to
the skin for pain control
• Produces segmental inhibition in the
dorsal horn, as well as descending
inhibition, and stimulates the release
of endogenous opioids to relieve pain
at both low and high frequencies
• Combine with medication, high-
frequency TENS for 30 minutes per
day during total periods of 4 to 8
weeks
• NNTs were 3.3 in the transcutaneous
electrical nerve stimulation plus
cobalamin group and 4.3 in the
transcutaneous electrical nerve
stimulation plus cobalamin and
lidocaine

21. Stellate Ganglion Block
• Sympathetic nervous system is
believed to be an important
mediator of pain
• After nerve injury or tissue
inflammation, collateral sprouting
in the peripheral and dorsal root
ganglia and the upregulation of
functional adrenoceptors may lead
to the formation of anatomic and
chemical couplings between
sympathetic postganglionic and
afferent neurons
• Sympathetic terminals also
contribute to the sensitization of
nociceptive afferents
• Mechanisms by which the
sympathetic nervous system
affects postherpetic neuralgia
remain uncertain

22. Stellate
Ganglion
Block

23. Paravertebral
Block
• Common alternative to epidural
injection, might provide short-term
relief of intractable postherpetic
neuralgia
• paravertebral block was also used to
prevent postherpetic neuralgia in
patients with acute herpes zoster-
related pain
• a lower VAS score and reduced doses
of pregabalin and acetaminophen
were observed during the first 4 weeks
after a single paravertebral block
injection, although the effects did not
persist beyond that point

24. Dorsal Root Ganglion Destruction
• PHN, the pain sensation may be caused by
an ectopic discharge in the nociceptors
and low-threshold afferents at the dorsal
root ganglion
• Use Adriamycin, is an anthracycline
topoisomerase II inhibitor, associated with
cytotoxic effects such as apoptosis,
autophagy, and necrosis à it could be
used to destroy the dorsal root ganglion,
and thus relieve pain by disrupting the
related signaling pathway
• In Indonesia à Use RF Ablation

25. Pulsed Radiofrequency (PRF)
• A minimally invasive, targetselective
technique that can be used to reduce
chronic postherpetic neuralgia-related
pain
• The underlying mechanism is attributed
to the effects of a rapidly changing
electrical field on neuronal membranes,
which results in electrolyte conduction
and subsequent depolarization
• Mitochondrial degeneration and a loss
of nuclear membrane integrity in the
continuous RF, but not in the PRF.
pulse frequency of 2 Hz and a pulse width of 20 ms

26. Pulsed Radiofrequency (PRF)
• All study
outcomes
favored pulsed
radiofrequency
• Observed
effects began
on Day 2 or 3
after treatment
and persisted
for 2-6 months

27. In Our Pain Clinic (RSUD Dr Moewardi)
• A 56 yrs old with severe PHN, VAS 8-9, burning, lancinating in the are right costa 4-5-6.
there were also allodynia around the burning lesion.
• It was already given gabapentine, mecobalamin and amitriptilline from previous hospital
for more than 4 months, and the pain better after take the medicine (VAS 5-6), but some
time “explosive pain” (VAS 9).
• We Injected Triamcinolon + Lidocain in Paravertebral Block USG Guide, and suddenly VAS
1-2.
• 1 week after à pain is already controlled (VAS 1-2) and gabapentine stoped, plan to
follow up for 2 weeks.
• We lost of follow up

28. Conclusion
• PHN remains a potentially debilitating and undertreated
form of neuropathic pain
• Conservative treatment still the first line of therapy
• With the advent of IPM options, one can provide
effective and long-lasting pain relief to patients not
responding to medical management
• the current evidence is insufficient for determining the
single best interventional treatment
• Considering invasiveness, price, and safety, the
subcutaneous injection of botulinum toxin A or
triamcinolone, transcutaneous electrical nerve
stimulation, and stellate ganglion block are
recommended first, followed by paravertebral block and
pulsed radiofrequency
• If severe pain persists, spinal cord stimulation could be
considered

29. Thank You
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