Diagnosis and Treatment of Trigeminal Neuralgia

1
Diagnosis and Treatment of Trigeminal Neuralgia
2
Trigeminal Nerve Anatomy
3
Functional Anatomy

• GSA general sensation from head and facial
  structures
• Main sensory nucleus
• Descending tract of V to spinal trigeminal
  nucleus
• Functional equivalent of substantia gelatinosa of
  spinal cord
• GSE muscles of mastication
• SVE branchial arch muscles
• Tensor veli palatini
• Tensor tympani

4
Demographics

• Slight female predominance
• Female 5.9 per 100,000
• Male 3.4 per 100,000
• Right side affected slightly more often
• Occasional familial occurrences
• Slightly elevated risk associated with HTN and
  multiple sclerosis

5
Classic Trigeminal NeuralgiaBurchiel Type I

• Brief (seconds to minutes) episodes of severe,
  sharp, stabbing, lancinating, pain
• Almost always unilateral
• Bilateral V1 pain sugestive of MS
• Pain occurs along one or more trigeminal
  divisions
• Spontaneous or evoked pain
• Cutaneous trigger zones
• Multiple attacks may occur over short periods
• Asymptomatic between attacks
• Normal facial sensation

6
BurchielClassification of Facial Pain

• Spontaneous Onset
• TN Type 1 (Classic TN)
• gt 50 episodic pain
• TN Type 2 (Atypical TN)
• gt 50 constant pain
• Trigeminal Injury
• Symptomatic TN (Multiple sclerosis)
• Trigeminal neuropathic pain (post-traumatic)
• Trigeminal deafferentation pain (RF lesion, GKR,
  etc.)
• Post-herpetic facial pain
• Secondary TN
• Tumors, aneurysm, AVM, etc.
• Atypical facial pain (somatiform pain disorder)

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Age of Onset
More than 70 of patients with TN are over 50
years of age at the time onset
8
Distribution of Pain by Division
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Diagnosis of Trigeminal Neuralgia

• ALL FACIAL PAIN IS NOT TRIGEMINAL NEURALGIA!
• Successful treatment of any patient with facial
  pain in general and TN in particular depends on
  making the correct diagnosis at the outset

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Pharmacological Treatment for Trigeminal Neuralgia

• AEDs are the cornerstone of treatment
• Start low, titrate to relief or side effects
• Monitor side effects and drug interactions
• Monitor levels and blood tests if indicated
• Rotate other AEDs or add as needed
• Tegretol remains the gold standard
• Response thought to be diagnostic

Tegretol is the ONLY drug that has been shown to
be effective for treatment of TN in a randomized
controlled trial
11
Pharmacological Treatment

• AEDs
• Tegretol (carbamazepine)
• Tripeptal (oxcarbazepine)
• Dilantin (phenytoin)
• Neurontin (gabapentin)
• Lyrica (pregabalin)
• Lamictal (lamotrigene)
• Topamax (topirimate)
• Gabatril (tiagabine)
• Keppra (levateracitam)

• TCAs
• Elavil (amitriptyline)
• Pamelor (nortriptyline)
• Desipramine (norpramin)
• Baclofen (lioresal)
• Opioids

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Adverse Effects of AEDs

• Cognitive changes
• Sedation
• Nystagmus, ataxia, diplopia, dizziness
• Nausea, vomiting, headache
• Allergic reaction
• Up to 7 with CBZ
• Some cross-reactivity between CBZ and PHT

13
Imaging in Trigeminal Neuralgia

• In patients with types 1 and 2 trigeminal
  neuralgia (TN1 and TN2) one can identify
• Presence of neurovascular compression (NVC)
• Degree of NVC
• Nature of the compressing vessel
• Location of NVC along the nerve
• Findings can be confirmed during MVD

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CB - MRA (TOF)
Right Trigeminal Nerve
Compressing vessel
15
CB - T1 (FSE) Gad
Right Trigeminal Nerve
Compressing vessel
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3D TOF
3D FSE Gad
3D T2
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MRI does accurately predict the symptomatic side

• Ho (null hypothesis) there is no difference
  between MRI prediction and surgical side
• Result Fail to reject Ho (P 0.40)
• MRI does predict the symptomatic (surgical) side
• Sensitivity of MRI for predicting symptomatic
  side 78

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The symptomatic nerve shows a higher degree of
compression than the asymptomatic nerve

• Ho (null hypothesis) there is no difference
  between degree of compression on symptomatic and
  asymptomatic side
• Reject Ho (P 0.0003)
• MRI does demonstrate a higher degree of
  compression on the symptomatic side

19
MRI can accurately detect arterial v. venous
compression

• Ho (null hypothesis) MRI cannot distinguish
  between arteries and veins compressing the nerve
• Reject Ho (P 0.36)
• MRI can differentiate arterial and venous
  compression
• Highly correlated with surgical findings

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Surgical Treatment of TN

• Microvascular decompression (MVD)
• Percutaneous ablative procedures
• Radiofrequency gangliolysis
• Glycerol rhizolysis
• Balloon compression
• Stereotactic radiosurgery
• Gamma knife
• Linac-based
• Peripheral ablative procedures (V1 and V2 pain)
• Peripheral branch neurectomy
• Alcohol neurolysis
• Open destructive procedures
• Partial sensory rhizotomy
• Subtemporal ganglionectomy (Frazier-Spiller
  procedure)

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Advantages of MVD

• MVD is the ONLY non-destructive procedure for the
  treatment of TN
• Low risk of facial sensory loss with subsequent
  dysesthesias or anesthesia dolorosa
• ONLY operation that addresses what is believed to
  be the primary underlying pathology i.e.
  vascular compression
• Long-term results are at least equivalent if not
  superior to any other procedure

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Disadvantages of MVD

• Requires major surgery may not be suitable for
  patients with significant medical co-morbidity
• MVD is generally associated with more risks than
  percutaneous procedures or radiosurgery
• More costly than percutaneous procedures

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Surgical Technique

• Positioning
• Skin Incision
• Iniomeatal line transverse sinus
• Digastric groove
• ¾ - ¼ rule
• Retromastoid craniectomy
• Expose sigmoid-transverse sinus junction
• Mastoid emissary vein
• Bevel bone laterally
• Sufficient anterior exposure reduces amount of
  cerebellar retraction
• T-shaped dural opening
• Exposure of most superior and lateral corner

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Surgical Technique

• Exposure of CPA
• Turning the corner is the most dangerous stage
  of the operation and must be executed with
  patience and the utmost care (Peter Jannetta)
• CSF drainage
• Gentle retraction of ala of cerebellum
• Identify and divide petrosal vein
• Visualization of trigeminal nerve
• Visualize the ENTIRE nerve from its exit from
  the pons to its exit laterally from the CPA
• Decompression
• Mobilize and pad arteries
• Coagulate and divide veins

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Operative Findings

• Arterial compression
• Superior cerebellar artery (SCA) most common
• AICA
• PICA
• Vertebrobasilar artery
• Venous compression
• More common with atypical TN
• Combined arterial and venous compression

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Intraoperative Observations

• 579 consecutive patients undergoing MVD
• 97 (560/579) had one or more vessels
• Multiple vessels found in 38
• SCA 88
• AICA 25
• Vein 28
• Basilar artery 4
• Location of NVC (medial-lateral)
• Trigeminal REZ 52
• Middle 1/3 54
• Lateral 10

Sindou M, et. al. Acta Neurochir (Wien)
1441-12, 2002
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Intraoperative Observations

• Location of NVC
• Supero-medial 53.9
• Supero-lateral 31.6
• Inferior 14.5
• Severity of NVC
• Simple contact 17.6
• Distorsion of nerve 49.2
• Marked indentation 33.2
• Other Findings
• Global atrophy 42
• Arachnoid thickening 18
• Angulation near petrous bone 13

Sindou M, et. al. Acta Neurochir (Wien)
1441-12, 2002
28
Operative Findings
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Complications of MVD

• Cerebellar injury lt1
• Infectious complications
• Bacterial meningitis
• Aseptic meningitis
• CSF leak 0-4
• Cranial nerve deficits
• Diplopia
• Sensory loss or dysesthesias 0.5-17
• Facial weakness 0.5-15
• Hearing loss lt1 (0-19)
• Stroke
• Mortality lt 1

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Complications of MVD
Author and Year N CSF V VII VIII Death
Breeze 1982 52 2 17 15 11 0
Van Lovern 1982 23 13 9
Apfelbaum 1983 406 1 3 1
Kolluri 1984 72 11 19 0
Piatt 1984 103 2 1 1 8 1
Zorman 1984 125 4 2 3 0
Bederson 1989 166 4 3 5 5 0
Klun 1992 220 0 0.5 0.5 4.5
Sun 1994 61 7 3 6 0
Barker 1996 1204 0.2 1 0.5 1 0.2
Kondo 1997 281 4-7
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Outcome Following Initial MVD(N1204 patients)
Barker F, Jannetta P, Bissonette D, et.al. NEJM,
1996
32
MVD - 10-Year Outcome Barker F, Jannetta P,
Bissonette D, et.al. NEJM, 1996
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Long-Term Results of MVDTypical TN

• Review of 19 series with 2,747 patients
  (17-1,204)
• Average follow-up, 4.4 years (4 months to 10
  years)
• 78 with excellent-good results (62-92)
• gt90 initial success with positive findings
• Failure rate 22 (8-30)
• Complications 4-34
• Facial numbness, 3-29
• Hearing loss, 0-19
• Mortality, 0.5

Lovely T, Janetta P Neurosurgery Clinics of
North America. 1997
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Long-Term Results of MVD
Series of Pts. FU (yrs) Dysesthesias () CN Palsy Post-Op Morbidity Long-Term Pain Relief ()
Bederson, 1989 166 5.1 3 3 21 75
Sindou, 1990 120 4.8 NR NR 79
Klun, 1992 178 5.2 0 0.6 88
Cutbush, 1994 109 4.8 0 7 NR 76
Mendoza, 1995 133 5.4 0 1.5 NR 71
Barker, 1996 1204 10 1 2 11 64
Kondo, 1997 281 12.6 NR 5.5 19 87
Lee, 1997 146 7.2 NR NR NR 84
Pagura, 1998 203 5 0.5 1 13 68
TOTAL 2540 7 0.8 3 16 77
Taha and Tew
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Factors Influencing Outcome of MVDDuration of TN

• Kolluri et. al., 1984
• TN gt 4 years Recurrence 25
• TN lt 4 years Recurrence 15
• Bederson et. al., 1989
• TN gt 4 years Excellent/good 91
• TN lt 4 years Excellent/good 75
• Broggi, et. al., 2000
• TN gt 7 years ONLY poor prognostic factor for
  favorable outcome

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Factors Influencing Outcome of MVDPrevious
Ablative Procedures

• Barba et. al., 1984
• Success rate of MVD reduced from 91 to 43
• Bederson et. al., 1989
• Excellent outcomes reduced from 78 to 63
• Walchenbach et. al., 1994
• Past ablative procedure - 50 good result
• MVD primary procedure 86 good result
• Best result appear to be achieved when MVD is
  performed as the primary procedure for treatment
  of TN

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Special Considerations

• MVD in elderly patients
• Typical (Type I) vs. atypical TN (Type II)
• Repeat MVD
• Role of MVD in patients with MS
• MVD following percutaneous procedures

38
Repeat MVD for Recurrent TN

• All procedures used to initially treat TN CAN be
  effective for recurrent TN
• Less than 1/3 of patients undergo repeat MVD
• Lower success rates
• Findings New compressive vessel, compression by
  felt
• Higher incidence of perioperative morbidity
• Increased risk of cranial nerve palsy
• Increased incidence of facial numbness (8)
  and/or facial dysesthesias

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Typical vs. Atypical TN Tyler-Cabara E, et.al.
J Neurosurgery 96527-531, 2002
40
MVD in Elderly Patients Ashkan K, Marsh H
Neurosurgery, 55840-850, 2004
Study Group Control Group
Age 65 (60-75) 46 (20-59)
Time to Diagnosis 7 yrs (1-22yrs) 3 yrs (3mos-20yrs)
Initial Relief 98 100
Mean LOS 5.4 days (3-10) 5.3 days (3-9)
Avg. Follow-Up 30 months 33 months
Mortality/Serious Morbidity None None
Recurrence 24 27
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MVD in Multiple Sclerosis

• MS traditionally considered an absolute
  contraindication to MVD
• Presumption that demyelination is the exclusive
  causative factor for TN in MS
• Neuroimaging has raised the possibility of a role
  for vascular compression
• Add Galligan)

42
MVD in Multiple Sclerosis Broggi et. al.
Neurosurgery, 55830-839,2004

• 35 MS patients with medically-intractable TN
• 74 - MRI evidence of demyelinating lesion on the
  symptomatic side (26 of 35)
• 46 (16 of 35 patients) had obvious vascular
  compression
• Long-term outcome
• Excellent 39
• Good 14
• Fair 8
• Poor 39
• Results of MVD in MS patients are much less
  satisfactory than in the idiopathic group.

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MVD in Multiple Sclerosis

• 9 patients with MS underwent PF exploration
• 7 MVD alone
• 2 MVD PSR
• 100 evidence of vascular compression on MRA
• Initial pain relief excellent in all patients
• Recurrence
• 5 of 7 with MVD alone
• 1 of 2 with MVD PSR
• 4 of 9 patient had long-term pain relief
• Because of the high recurrence rate together
  with the morbidity.MVD should not be offered to
  patients with TN and MS.

Eldridge P, et.al. Stereotact Funct Neurosurg
8157-64, 2003
44
Percutaneous Procedures

• Radiofrequency thermal coagulation
• Glycerol rhizolysis
• Balloon compression

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(No Transcript)
46
Needle Insertion
47
Radiofrequency Lesion
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Glycerol Injection
Contrast in trigeminal cistern
Contrast under temporal lobe
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Balloon Compression
50
MVD vs. Percutaneous Procedures

• INITIAL PAIN RELIEF
• MVD 98
• RF rhizotomy 98
• Balloon 93
• Glycerol 91
• RECURRENCE RATES
• Glycerol 54 (4 years)
• RF rhizotomy 23 (9 years)
• Radiosurgery 25 (3 years)
• Balloon 21 (2 years)
• MVD 15 (5 years)

Taha J, Tew J Neurosurgery 38865871, 1996
51
Trigeminal Nerve Complications
MVD PRFTG PGR PBC
Numbness 2 98 60 72
Dysesthesia 0.5 24 16 19
AD 0 1.5 1.8 0.1
Corneal reflex 0.05 7 3.7 1.5
Keratitis 0 1 1.8 0
Motor 0 24 1.7 66
Taha J, Tew J Neurosurgery 38865871, 1996
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Radiosurgery for TN
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Duration and Maintenance of Pain Relief
More than 50 pain relief/Complete relief 1
year 75.8 2.9 63.6 3.3 2 years 71.3
3.3 59.2 3.5 3 years 67.2 3.9 56.6
3.8 3.5 years 65.1 4.3 - 5 years 55.8
9.3 37.7 15.6
54
GKR
55
GKR
56
GKR
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Decision-Making in TN

• When should surgery be considered?
• Success/failure of medical therapy
• Frequency of recurrences
• Duration of symptoms
• Which operation should be done?
• Age and health of patient
• Willingness to except facial sensory loss
• Previous procedures for TN
• Desires of patient
• Experience of surgeon

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Glossopharyngeal Neuralgia

• Pain most often occurs in the territory of the
  glossopharyngeal nerve
• GSA input from external/middle ear, posterior
  tongue, and pharnyx
• Classic GPN pain primarily in tongue and
  pharnyx
• Otalgic GPN pain primarily occurs in ear
• Unilateral, paroxysmal, lancinating pain last
  seconds to minutes
• Pain may occur in clusters
• Irregular intervals over days, weeks or months
• Spontaneous occurrence or precipitated by
  swallowing
• Peak incidence 5th to 7th decade
• Pain relieved by anesthetizing posteior pharynx
  with 10 cocaine
• 5 - 8 of cases caused by posterior fossa tumor
• Pain may be due to elongated styloid process
  (Eagles syndrome)

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GPN vs. TN

• TN 70-100x more common than GPN
• GPN shows no sex predilection
• TN slightly more common in women (32)
• GPN occurs more commonly on the left side (32)
• TN more common on the right (53)
• Bilateral involvement is uncommon in both
  conditions
• TN 4 GPN 2
• Clinical presentation of GPN tends to be more
  variable
• 10 of patients have BOTH TN and GPN
• Secondary GPN usually associated with malignant
  skull base neoplasms
• Secondary TN due to benigng intradural tumor
• MS almost never encountered in association with
  GPN

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Treatment of GPN

• Medications tend to be less effective than in
  patients with TN
• Microvascular decompression of the 9th and 10th
  cranial nerves
• Intracranial rhizotomy of 9th nerve and upper
  1/3 of vagus
• 85 success rate
• 20 risk of swallowing dysfunction
• Percutaneous glossopharyngeal rhizotomy

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Summary and Conclusions

• All procedures are initially highly effective in
  alleviating the symptoms of TN
• Each case should be treated individually and
  multiple options should be discussed and offered
  to each patient.