Trigeminal neuralgia is a condition characterized by severe, sporadic facial pain. It has been described and studied historically since the 2nd century AD. Modern management involves drug therapies like carbamazepine as first line treatment. When medications fail, various surgical procedures can be used including percutaneous glycerol rhizotomy, balloon compression, and radiofrequency rhizotomy. These aim to destroy nerve fibers supplying the trigeminal ganglion to relieve facial pain from trigeminal neuralgia.

1. Management of
Trigeminal Neuralgia
DR PRAVEEN K TRIPATHI
1

2. “ …. as it were a flash of fire all of a sudden shot
into all those parts …. which made her shreeke
out…”
Letter to a friend by John Locke
December 4, 1677
4-May-16
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3.  2nd Century – Aretaeus of Cappodocia in “Cephalaea”.
 1037 AD – Avicenna.
 1677 – John Locke first description.
 1756 – Nicolas Andre – “tic douloureux” “Cynical spasm”.
 1773 – John Fothergill – “Fothergill’s Disease”
 1829 – Bell – Anatomy of 5th nerve
HISTORICAL PROSPECTIVE

4.  1853 – Trousseau – “ Neuralgia epileptiform”
 1942 – Bergouignan – Phenytoin
 1962 – Blom – Carbamazepine
 1934 – Dandy – Vascular compression of nerve
 1967 – Peter Jannetta devised MVD
1998 - Khan—Gabapentin, for frequency rhizolysis,
trigeminal neuralgia in temperature monitoring, multiple
sclerosis
2007 - Obermann—Pregabalin
HISTORICAL PROSPECTIVE

5. Anatomy
Origin – Gasserian ganglion Upper Ventral Pons
4 Nuclei – Principal Sensory
Motor
Spinal
Mesencephalic
3 roots –Portio Major – 125,000 fibers – 50% unmyelinated
Portio Minor – 3000 – 7500 fibers – 20% unmyelinated
Intermediate
3 divisions + 3 autonomic ganglia
Ophthalmic Ciliary
Maxillary Sphenopalatine
Mandibular Otic 4-May-16
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6. Anatomy
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7. Trigeminal ganglia
 Covering –contained in a dural pouch
known as cavum trigeminale(menkel,s
cave)
 Dural extend forward as a ballooning
of meningeal layer of dura mater from
posterior cranial to middle cranial
fossabelow attached margin of
tentorium cerebelli
 Cavum-
Roof-formed by two meningeal layer
Floor-one meningeal and one endosteal
layer
4-May-16
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8. Definition
 Trigeminal Neuralgia is a clinical syndrome
distinguished by brief paroxysms of Unilateral,
lancinating facial pain in the 5th nerve
distribution triggered by cutaneous stimuli, such
as a breeze on the face, chewing, talking or
brushing the teeth.
4-May-16
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9. Epidemiology
 Incidence, approximate at 5 in every 100 000
 Gender ratio of female : male = 2:1
 Right sided 56% of the time
 Maxillary (V2) > Mandibular (V3) > Ophthalmic (V1)
 Mean age at diagnosis is 60 years-old
 It occurs mostly after 5th decade.↑ frequency with age,
highest at >80 years old
 10-15% of patients seeking care at dental specialty 4-May-16
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10. Etiology of TGN
 Medical: MS, Charcot Marie Tooth disease, Lyme disease, infarct,
Rhombencephalitis .
 Surgical: 1. Vascular Compression - Superior Cerebellar artery.
Anterior inferior cerebellar artery
Pontine perforator from basilar
Petrosal Vein
Vertebrobasilar Dolichoectasia
2. Other Vascular Lesions - AVM
Aneurysm
3. Tumors - Schwannoma
Meningioma
Epidermoid
Lipoma
Metastasis
4-May-16
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11. Etiology and
Pathophysiology….
Older ideas
 Epileptogenesis (seizures from the brain)
Newer theories
 Ectopic nerve firing (seizures in the nerve)
 Ephapsis (cross-wirednerves)
4-May-16
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12. Etiology and
Pathophysiology….
• Demyelinative lesions of trigeminal fibers
appear to set up ectopic generation of
spontaneous nerve impulses and their ephaptic
conduction to adjacent fibers. (Gardner)
• This can lead to pain attacks at the slightest
stimulation of any area served by the nerve .
• It also hinder the nerve's ability to shut off the
pain signals after the stimulation ends 4-May-16
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13. PATHOPHYSIOLOGY
Chronic
irritation of
the
trigeminal
nerve
failure of
segmental
inhibition in the
trigeminal
nucleus,and
ectopic action
potentials in the
trigeminal
nerve.
increased
firing and
impaired
efficiency of
inhibitory
mechanisms
paroxysmal
discharges
in the
trigeminal
nucleus
attacks of
trigeminal
neuralgia
4-May-16
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14. CROSS TALK
NORMAL NERVES
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15. Normal Trigeminal Nerve
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16. Vascular compression of V nerve
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17. Vascular irritation of V Nerve
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18. Definition and classification of TN
Defining Symptomatology Diagnostic Classification
Idiopathic
sharp, shooting, electrical shock–like, Episodic pain TN1
aching, throbbing, burning, >50% constant pain TN2
Trigeminal injury
unintentional (facial trauma; oral op;ear, nose, & throat op; skull base
op; posterior fossa op; or stroke)
Trigeminal Neuropathic pain
intentional (neurectomy, gangliolysis, rhizotomy, nucleotomy, tractotomy,
or other denervating procedure)
Trigeminal deafferentation pain
Associated w/ MS symptomatic TN
Resulting from an outbreak of facial Herpes zoster post herpetic TN
Somatoform pain disorder atypical facial pain*
* Evaluation needed with psychological testing prior to confirmation.
4-May-16
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19. Clinical Features
 Female: Male =2:1
 6th decade (22months – 94yrs)
 Family History – 5%
 Bilateral, Sequential – 5%
 Commoner on right side(White & Sweet),R-61%: L-35%: B/L–4%
 V2+V3–32% : V2–17% : V3-15% : V1+V2+V3-17% : V1 rare
 Trigger areas – triggering stimuli
 Clicking in the ear
 Auricular Pain
 Absent during sleep
 Relief with Carbamazepine in 70-90%(Tyler Kabara et al,2002)
4-May-16
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20. 4-May-16
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21. Signs
Corneal reflex
 Sensory examination – 25% have abnormalities
( Lewi & Grant, 1938)
 Motor examination – Asymmetrical jaw motion
 Ipsilateral nasolabial fold hypesthesia (Jannetta)
 Other deficits – Symptomatic TGN
4-May-16
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22. 4-May-16
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23. Trigeminal Neuralgia &
Multiple Sclerosis
 10-20% of patients with MS present with TGN
 1-8% of MS have TGN (Selby, 1984)
 Younger age group – 30 yrs mean
 Bilateral pain commoner than in idiopathic
TGN
 MR imaging may pick up sclerotic plaque at
root entry zone
 2% of all TGN 4-May-16
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24. Investigations
 X-Ray skull – AP through orbit, lateral,
Towne’s view
 CT head
 MRI Brain
 Electrophysiological Tests
– Evoked Potential (Lunsford et al, 1985)
- Nd: Yag Laser Pulses (Romaniello et al,
2003) 4-May-16
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25.  Higher petrous apex
– Gardner et al, 1956 – 3 times higher incidence
 Tip of dens > 5mm above McGregor’s line (43% vs 23%
in controls)
 Basilar Impressions
 Dolichocephaly
 Paget’s disease
 Postmenopausal Osteoporosis
X-Rays in TGN
4-May-16
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26. MRI in TGN
Indications – Young patients
- Bilateral pain
- Atypical Neuralgia
- Neurologic deficits
MRI with MRA – Patel et al, 2003 – 92 patients
- 90.5% sensitivity, 100% specificity
MR tomographic angiography – Fukuda et al, 2003 – 67% correlation
MRI with constructive interference in steady state
- Yoshino et al, 2003 – 80% correlation
Functional MRI, PET Scan with Opioidergic Imaging 4-May-16
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27. 27

28. CB - MRA (TOF)
Right Trigeminal Nerve
Compressing vessel

29. CAVERNOUS ICAANEURYSM
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30. Diagnosis
 TN is often misunderstood as pathology of dental origin. Many patients may
go untreated for long periods of time before a correct diagnosis is made.
 TN remains a clinical diagnosis.
 MRI and MRA can be performed if there is suspicion of underlying
pathology.
4-May-16
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31. Evolution of therapies for
TGN
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32. Medical Therapy – Later Medicines
Anticonvulsants
Muscle relaxants
Anti depressants
Topical agents
First generation:
Phenytoin
Carbamazepine
Valproate
Baclofen
Amitriptyline
Nortriptyline
Second generation:
Gabapentin
Oxcarbazepine
Lamotrigine
Zonisamide
Topiramate
Levetiracetam
Venlafaxine
Duloxetine
Pregabalin
32

33. Carbamazepine
• Blom, 1962
• Mainstay drug Therapy
• Controls pain initially in approximately 90% of cases
(Liu J.K, Apfelbaum; 2004)
• Started as low dose dose escalation; drug synergism
• Oxcarbazepine better tolerated (Beydoun.A, 2002)
•Side effects: Leucopenia
Hyponatremia
Rashes
Elevation of Liver enzymes
Alterations of Lipid profile
Osteomalacia
33

34. Medical Treatment of TN
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35. 4-May-16
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36. Pain assessment
(Barrow Neurological Institute score)
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37. Surgical Therapy
Indications :
- Failure of medical therapy
- Intolerable adverse effects of drugs
Methods:
- Percutaneous
- Open surgery
- Radiosurgery
4-May-16
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38. Percutaneous Procedures
• Chemoneurolysis – Glycerol Rhizotomy
• Stereotactic Radiofrequency Rhizotomy
• Balloon compression
• Peripheral Neurectomy
38

39. Chemoneurolysis
• Bartholow (1876) – Chloroform : Neuber (1883) – Osmic Acid
• Schloesser (1904) – Alcohol
• Wright (1907) – Osmic Acid gangliolysis
• Harris (1910) – Alcohol gangliolysis
• Hartel (1914) – Percutaneous extra oral foramen ovale
method
39

40. Percutaneous Retrogasserian
Glycerol Rhizotomy
• 1981 – Hakanson – Glycerol+Tantalum dust
• Principle effects of Glycerol
- Neurolytic
- Hyperosmolarity
- Affects large diameter Axons
- Esp. previously demyelinated axons
- Affects the trigger mechanism
- May down regulate central hyperexcibility
- Bengt Linderoth, Sten Hakanson
40

41. Indications of PRGR
 The main indication for glycerol rhizolysis
remains classic idiopathic TN.
 In medically infirm patients
 Anticonvulsants or baclofen causing severe
intolerant side effects particularly to patients
with paroxysmal facial pain associated with
multiple sclerosis (MS).
4-May-16
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42. Technique of PRGR
• No intra-op patient co-operation required – GA
• Position – initially supine – completed in semisitting
• Hartel’s technique
• Cisternography to assess volume
• Average 0.25ml (0.2-0.5ml)
• 99.9% anhydrous glycerol + tantalum injection
• Placed in semisitting position for 2hrs after the procedure
42

43. 4-May-16
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Hartel’s anatomic landmarks for access to the foramen of ovale.
A.Surgeon marks three points on the patient’s face:
•A point 3 cm anterior to the external auditory meatus along a line from the external
auditory meatus to the tip of the nose ,
•A point beneath the medial aspect of the pupil on the lower eyelid, and
•A point 2.5 cm lateral to the oral commissure .
B.The target is the foramen ovale, at the intersection of a vertical line (in the sagittal
plane) extending through the point beneath the pupil (1) and a horizontal line (in the axial
plane) through the point anterior to the external auditory meatus (2).

44. Technique of PRGR
• 22-gauge lumbar cannula is
inserted from a point approximately
3 to 4 cm lateral to the corner of the
mouth.
•The trajectory is aimed at a point
that lies, in the lateral view,
approximately 0.5 cm anterior to the
anterior margin of the mandibular
joint, and in the anteroposterior
view, toward the medial margin of
the pupil with the eyeball in the
neutral position. 4-May-16
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45. Cannula trajectory toward the superior-medial aspect of the foramen ovale.
A. The surgeon’s index finger rests alongside the molars, against the lateral pterygoid, to guide
the cannula toward the foramen ovale and prevent penetration of the oral mucosa. The cannula is
aimed at the foramen ovale via Hartel’s landmarks.
B. If direct penetration of the foramen is not achieved, the surgeon can sequentially walk down
the infratemporal fossa (arrow) to the superomedial aspect of the foramenovale.
4-May-16
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46. Technique of
PRGR
Consecutive axial CT scan
images of a patient with
intracisternal tantalum
dust.
The anteroposterior
distance from the anterior
portion of the oval
foramen to the anterior
portion of the mandible is
measured.
4-May-16
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47. Complications of PRGR
• Headache – 15%
• Nausea, vomiting – 8%
• Depressor response – 15%
• Aseptic meningitis – 0.6%
• Herpes simplex perioralis – 37%
• Sensory loss – 51%
• Dysesthesia – 2%
Lunsford et al, 1997
47

48. Percutaneous Balloon
Compression (PBC)
Principle:
Destruction of large myelinated pre-ganglionic fibers by
compression against petrous bone and dural edge.
•GA, pacemaker, slight neck extension, flouroscopy
•Hartel’s technique
•#4 Fogarty catheter 17 to 22 mm beyond foramen at the porus
trigeminus
•0.75 to 1cc of 180mg% iohexol under pressure of 1200-1500mm Hg
•Tissue compression pressure – 650 – 950 mm Hg
•Upto 1 minute or 1.5 min in recurrence
•Proper inflation – Pear shape : depressor response
Technique of PBC
48

49. Percutaneous Radiofrequency
Stereotactic
Rhizotomy (PSR):
•Failure of drug therapy or adverse effects
• Advanced physiologic age
• Poor medical condition
• Multiple Sclerosis
• Patient’s choice
Indications of PSR
4-May-16
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50. Principle : Selective destruction of A-delta & C fibers at lower
temperatures
Technique of PSR
•Day care procedure under image guidance
• Supine, Neutral position of head, short GA
• Hartel’s technique
• Proper positioning indicated by CSF flow
• Electrode localisation
• Lesioning at 60-70 degree Centigrade for 70 seconds
• Sequential lesions of 90 seconds with 5 degree Centigrade after
each lesion
• Dense hypalgesia in desired area subjectively assessed.
50

51. Complications of PSR
Common:
Dysesthesia – 11%
Anaesthesia dolorosa – 0.2%
Absent corneal Reflex – 3%
V1, V2, V3 pain – 10.3%
Keratitis – 0.6%
Diplopia – 0.5%
Masseter weakness – 7%
Rare:
Intracerebral Hemorrhage
Stroke
Meningitis
Blindness
Carotico – Cavernous Fistula
Temporal lobe abscess
Seizures
Tew JM Jr, Taha JM – 1995
51

52. Vascular Compression of the Nerve
Demyelination of Axons
Ephaptic Transmission
Impaired segmental inhibition
Central Nuclear hyper activity
TGN
Principle of MVD
4-May-16
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53. Vascular Compression
Arterial –56-76%
 Superior Cerebellar –(75.5%)
 Anterior Inferior cerebellar – 0-21%
 Other Arterioles
Venous 33-50%
 Trigeminal Vein
 Petrosal Veins
4-May-16
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54. SCA COMPRESSION
A.The right trigeminal nerve is
compressed by a tortuous basilar
artery and the left trigeminal nerve is
compressed by the main trunk of the
SCA.
B. SCA bifurcates into rostral and caudal
trunks before reaching the trigeminal
nerve. The nerve is compressed by the
caudal trunk.
C. SCA bifurcates distally to the nerve.
The nerve is compressed by the main
trunk.
D. SCA bifurcates before reaching the
nerve. The nerve is compressed by
both the rostral and caudal trunks.
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55. E. the nerve is compressed by a large pontine artery.
F. the nerve is compressed by an AICA that has a high origin and loops
upward into the medial surface of the nerve. The SCA passes around the
brainstem above the nerve.
.
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56. Venous Compression
 Superior petrosal Vein that empty into the superior petrosal
sinuses most commonly compress the Trigeminal nerve
 Tributaries:
 Transverse pontine Vein (most frequent)
 Ponto trigeminal Vein
 Vein of cerbellopontine fissure and Middle cerebellar
peduncle
4-May-16
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57. A. Anterior view. The veins that commonly compress the trigeminal nerve are tributaries of the superior
petrosal vein
B. a transverse pontine vein compresses the lateral side of the nerve and joins the veins of the middle
cerebellar peduncle and cerebellopontine fissure to empty into a superior petrosal vein.
C. the medial side of the nerve is compressed by a tortuous transverse pontine vein.
D, the lateral side of the nerve is compressed by the junction of the transverse pontine vein with
the veins of the middle cerebellar peduncle and the cerebellopontine fissure 4-May-16
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58. Procedure of MVD
• Positioning – Mastoid topmost
• Retromastoid, suboccipital craniectomy – Dura opened
• Cerebellum retracted – arachnoid dissected
• Tackle petrosal veins, visualise the entire nerve
• Identify the offending vessel
• Teflon felt placement
• Wound closure
59

59. Procedure of MVD
For decompression of the fifth cranial nerve, the incision (dotted line) is positioned as shown
so that two thirds of the length is above the level of the mastoid notch.
4-May-16
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60. A. Schematic view of a left trigeminal
nerve decompression.
•The superior cerebellar artery is
compressing the superior edge of the
trigeminal nerve.
B. Elevation of the superior cerebellar
artery reveals indentation and grooving
by the artery.
C. Shredded Teflon felt is gently worked
in between the nerve and the
compressing artery.
D. The shredded Teflon felt is placed
between the artery and the nerve so that
the thrust of the arterial force is now
directed away from the underlying
nerve. 4-May-16
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61. Complications
 Positioning palsy
 Intracerebellar Hematoma & edema
 Hearing loss
Postop numbness, headache
 Hemorrhage
 CSF Leak
62

62. Results of MVD
• Average success rate 78%, >90% when vessels found
• Avg recurrence rate 20-25%
• Max recurrence within 2yrs
• Major complications around 4% - cranial nerve deficits
• Mortality – 0.5%
• Numbness – 3-29%
• Hearing Loss < 4%
63

63. Prognostic Factors in MVD
 Female gender
 Duration of symptoms > 8yrs
 Venous compression only
 Lack of immediate post-op pain relief
64

64. Gamma Knife Radiosurgery for TGN
• 1951 – Lars Leksell introduced
• Principle – Radiation induced damage to REZ after a latent period
- Minimising damage to surrounding structures.
•Indications: Failed medical therapy
Poor medical condition
Recurrent TGN
Patient’s choice
65

65. Gamma Knife
 Single high dose radiotherapy delivered with exquisite precision to a
radiographically defined target, at the junction of trigeminal nerve and brain stem.
 Success rate is 70%
4-May-16
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66. Technique of GKRS:
• Accurate imaging of the REZ with 1mm MRI slices
• 4mm isocenter targeted to REZ 2-4mm anterior to brain stem
• Brain stem receives < 20% isodose
• Length of nerve irradiated at 50% isodose is 4mm
• Total radiation dose of 70-90 Gy over 30mins
• Latent period for pain relief – upto 10 weeks
Robert W. Rand, 1997
67

67. Cyberknife Radiosurgery
• Developed in 1994 – Accuracy, Inc., Sunnyvale, CA
- Adler 1999, Chang 2001
• Non invassive head immobilisation & advanced image - guidance
• Dynamic tracking of skull – ensures target accuracy of 1.1mm
• Frameless procedure
• Delivers non isocentric, conformal, homogenous radiation to non
spherical structures.
• Romanelli et al, 2003 – 10 patients with Trigeminal Neuralgia –
70% response.
68

68. Technique
• Single session – Medium maximum dose 78 Gy,
median, marginal dose 65.5 Gy
• Median Target volume = 0.085 cm3
• Length of nerve encompassed by 79% isodose line =
7.2mm
• Target volume placed 2-3 mm anterior to REZ
69

69. Results:
• 92.7% successful pain relief at 7 days
• Pain relief – Excellent – 87.8 %
Moderate – 4.9%
No change – 7.3%
• Long Term response rate 78%
70

70. Complications
• 73.2% had facial numbers at follow-up
• Anesthesia dolorosa – 5%
• Depressed corneal reflex – 7.3%
• Masseter Weakness – 2.4%
• Trismus
71

71. 4-May-16
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72. Choice of surgical treatment
 Relatively young patients with no co-morbidities: MVD
 Patients unable to tolerate GA:
 Percutaneous procedures
 Stereotactic radiosurgery
 Multiple sclerosis: SRS/ Percutaneous techniques/MVD
 Final choice based on patient’s preference and ability to
tolerate GA
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73. Trigeminal Neuralgia: Opportunities
for Research
 Treatment of trigeminal neuralgia is like playing the game of
dart, so far .
• Treatment is empirical, but not satisfactory 4-May-16
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74. Individuals of note with TN include
 Entrepreneur and author Melissa Seymour (Australia) was
diagnosed with TN in 2009 and underwent microvascular
decompression.
 Salman Khan , was diagnosed with TN in 2011 He underwent
surgery in the US.
 All-Ireland winning Gaelic footballer Christy Toye was
diagnosed with the condition in 2013.
4-May-16
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