Trigeminal Neuralgia by Dr Abdi Ermolo neurosurgery resident

1. Trigeminal neuralgia
and Mgt principles
Abdi E
Jan 5 2018
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2. Outline
• Introducton
• Anatomy
• Pathophysiology
• Evalution
• Management
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3. Introduction
• Sharp, electric shock-like paroxysmal lancinating pain in the distribution
of one or more branches of the TN on one side
• Annual incidence 4/100,000
• 2% of pts with MS have TGN, ≈ 18% of pts with bilateral TGN have MS.
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4. Anatomy
• The trigeminal nerve leaves the midlateral surface of the pons and
enter Meckes cave
• The TN bas three divisions-
1 Ophthalmic (CNV1)
2 Maxillary (CN V2)
3 Mandibular (CN V3)
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5. Pathophysiology
• Due to ephaptic transmission in TN from large-diameter partially
demyelinated A fibers to thinly myelinated A-delta and C fibers
• Pathogenesis may be due to:
1. vascular compression of the TN at the REZ
a) most commonly (80%) by the SCA;
b) persistent primitive trigeminal artery
c) dolichoectatic basilar artery
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6. Pathophy…
2. posterior fossa tumor
3. MS, plaque within brainstem may cause TGN
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7. Evaluation and Diagnosis
1. History; diagnosis of TGN is based nearly entirely on the pt’s hx
2. Physical exam; unremarkable; minor sensory changes in the
corresponding distribution of the TN are not uncommon
3.Imaging; MRI or CT scan to exclude structural pathologies
 On high resolution T2W imaging, a vascular loop is often evident
compressing the TN.
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8. Evalution…
• Typical TGN ; caused by blood vessel compressing the TN root
• Atypical TGN ;a unilateral, prominent constant and severe aching and
burning pain superimposed upon otherwise typical symptom.
• Pre- TGN ;Days to yrs before the first attack of TGN pain, pts
experience odd sensations of pain, such as toothache or parasthesia.
• MS related TGN ;identical to typical TGN. Bilateral TGN is more
commonly seen in people with MS.
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9. Differential Diagnosis
• Dental pathologies, temporomandibular joint pain, eye pain, facial
trauma and bony fractures,
• Tumor of the facial bones or the trigeminal nerve, giant cell arteritis,
Tolosa-Hunt syndrome ,
• Trigeminal autonomic cephalgias and
• Other primary headache syndromes can cause facial pain
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10. Management
Medical therapy for trigeminal neuralgia
Carbamazepine;It initially provides 100% pain relief for 70% of pts
Baclofen ; 2nd DOC
May be more effective if used in conjunction with low dose
carbamazepine.
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11. Surgical therapy for trigeminal neuralgia
Aimed at either destroying parts of nerve fibers or decompressing
the trigeminal nerve to relieve pain
Indications for surgery
Refractory to medical management, or
Side effects of medications exceed risks and drawbacks of surgery.
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12. Surgical options
Surgical options for TGN fall into two categories:
1. Palliative destructive procedures
2. Physiologic nondestructive MVD
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13. Surgical…
• Palliative destructive procedures involve controlled damage to the TN
root with the aim of pain relief
• Include radiofrequency lesioning, glycerol rhizolysis, balloon
compression rhizotomy, and stereotactic radiosurgery rhizotomy
• recurrence rate of about 50% after 3 to 5 years
• MVD surgery is associated with an approximately 80% chance of pain
freedom among carefully selected patients.
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14. Surgical…
• Pts > 70 yrs should seek less invasive percutaneous procedures such as
balloon compression, radiofrequency, or glycerol rhizotomy.
• Radiosurgery is also an option but the chance of pain freedom without
medications is less
• Pts <40 yrs should be carefully evaluated before intervention because
disappointing recurrence of pain
• Atypical pain associated with burning neuropathic, rather than
neuralgic pain, is not amenable to surgery
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15. Surgical...
• Pts who cannot undergo MVD, balloon compression rhizotomy is
recommended because it is easy to perform and immediately effective.
• If the pt harbors comorbidities that preclude the use of GA and
immediate pain relief is not a concern, radiosurgery as a reasonable
option.
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16. Balloon Compression
• Injures medium and large myelinated fibers while sparing
small myelinated and unmyelinated fibers.
• Particularly useful in patients with V1.TN
• Contralateral master weakness is a relative contraindication
for this technique because BC causes temporary and
permanent masseter weakness
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17. Balloon …
A 20-year review of percutaneous BC of the trigeminal ganglion
• David J. Skirving, M.B.B.S. , and Noel G. Dan, F.R.A.C.S.
• Department of Neurosurgery, Concord Repatriation General Hospital, University of Sydney,
Austria
• 496 pts with typical symptoms of unilateral TGN who underwent 531
PBCs
9 technical failures.
522 successful procedures, prompt pain relief ensued in all pts except
one.
Recurrence of pain was found in 95 patients (19.2%) within 5 yrs and in
158 pts (31.9%) over the entire study period.
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18. Surgical…
Microvascular decompression
• Recommended for pts with inadequate medical control of pain with > 5
years anticipated survival
• Relief is often long lived, persevering 10 yrs in 70%.
• Incidence of facial anesthesia is much less than with PTR,
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19. Surgical…
• MVD for TGN involves identification of the TN and the offending
vessel through the retrosigmoid craniectomy putting a Teflon in b/n
the two.
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20. Surgical…
Microvascular decompression for trigeminal neuralgia
. Robert Breeze, M.D., and Ronald J. Ignelzi, M.D.
. Division of Neurological Surgery, University of California Medical Center, San
Diego, California
✓ 51 pts with TGN underwent 52 procedures for MVD.
85% early success rate;
13% late recurrence rate was found.
60% of the patients experienced some form of
complication, but in only 23% was the complication
persistent
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21. Surgical…
Preoperative Considerations
Neuralgic pain medications should be continued in the
perioperative period
Tapered off if the patient remains pain free for 1 week
after surgery
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22. Surgical…
Peripheral nerve ablation and neurectomies
Limited to pain or trigger points in territory of
supraorbital/supratrochlear, infraorbital, or inferiordental nerves.
Neurectomy may be a consideration especially for elderly patients
who are not candidates for MVD
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23. Surgical…
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24. Mgt of surgical treatment failures
90% of recurrences are in distribution of previously involved divisions;
10% in new division, represent progression of the underlying process
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25. Mgt…
PTR may be repeated in pts who have a recurrence with some
preservation of facial sensation.
MVD may be performed in pts failing PTR, but the success rate may
be reduced
SRS can be repeated, using the same dose, with reported significant
reduction in pain in 89%, and complete relief in 58%
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26. Mgt…
Intradural retrogasserian trigeminal nerve section
• May be used as a measure of last resort in pts who have recurrent
TGN following one or more PTRs in the presence of total facial
anesthesia, or
• In pts undergoing posterior-fossa craniectomy for the purpose of
MVD when no impinging vessel can be identified
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27. Reference
Greenberg Handbook of neurosurgery 8th Edition
Youmans and Winn Neurological Surgery 7th Editon
Jornal of Neurosurgery
The Neurosurgical Atlas
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