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 Neuralgia Burchiel 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)
> 50% episodic pain
TN Type 2 (Atypical TN)
> 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)

7. 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

9. 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

10. 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

12. 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

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

15. CB - T1 (FSE) Gad
Right Trigeminal Nerve
Compressing vessel

16. 3D TOF
3D FSE + Gad
3D T2

17. 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%

18. 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= )
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

20. 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)

21. 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

22. 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

23. Surgical Technique Positioning Skin Incision Retromastoid craniectomy
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

24. Surgical Technique Exposure of CPA Visualization of trigeminal nerve
“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 it’s exit from the pons to it’s exit laterally from the CPA
Decompression
Mobilize and “pad” arteries
Coagulate and divide veins

25. Operative Findings Arterial compression Venous compression
Superior cerebellar artery (SCA) – most common
AICA
PICA
Vertebrobasilar artery
Venous compression
More common with atypical TN
Combined arterial and venous compression

26. 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) 144:1-12, 2002

27. Intraoperative Observations
Location of NVC
Supero-medial %
Supero-lateral %
Inferior %
Severity of NVC
Simple contact %
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) 144:1-12, 2002

28. Operative Findings

29. Complications of MVD Cerebellar injury <1% Infectious complications
Bacterial meningitis
Aseptic meningitis
CSF leak %
Cranial nerve deficits
Diplopia
Sensory loss or dysesthesias %
Facial weakness %
Hearing loss <1 (0-19%)
Stroke
Mortality < 1%

30. Complications of MVD Author and Year N CSF V VII VIII Death
Breeze 52 2%
17%
15%
11%
Van Lovern 23
13% 9%
Apfelbaum
406 1% 3%
Kolluri 72
19%
Piatt
103 8%
Zorman
125 4%
Bederson
166 5%
Klun
220
0.5%
4.5%
Sun 61 7% 6%
Barker
1204
0.2%
Kondo
281
4-7%
% total (%permanent)
BSAER monitoring in 1980’s

31. Outcome Following Initial MVD (N=1204 patients)
Barker F, Jannetta P, Bissonette D, et.al.: NEJM, 1996

32. MVD - 10-Year Outcome Barker F, Jannetta P, Bissonette D, et. al
MVD - 10-Year Outcome Barker F, Jannetta P, Bissonette D, et.al.: NEJM, 1996

33. Long-Term Results of MVD Typical 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%)
>90% 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

34. 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 21 75
Sindou, 1990
120
4.8 NR 79
Klun, 1992
178
5.2
0.6 88
Cutbush, 1994
109 7 76
Mendoza, 1995
133
5.4
1.5 71
Barker, 1996
1204 10 1 2 11 64
Kondo, 1997
281
12.6
5.5 19 87
Lee, 1997
146
7.2 84
Pagura, 1998
203 5
0.5 13 68
TOTAL
2540
0.8 16 77
*Taha and Tew

35. Factors Influencing Outcome of MVD Duration of TN
Kolluri et. al., 1984
TN > 4 years Recurrence 25%
TN < 4 years Recurrence 15%
Bederson et. al., 1989
TN > 4 years Excellent/good 91%
TN < 4 years Excellent/good 75%
Broggi, et. al., 2000
TN > 7 years ONLY poor prognostic factor for favorable outcome

36. Factors Influencing Outcome of MVD Previous 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

37. 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

39. Typical vs. Atypical TN Tyler-Cabara E, et. al
Typical vs. Atypical TN Tyler-Cabara E, et.al.: J Neurosurgery 96: , 2002

40. MVD in Elderly Patients Ashkan K, Marsh H: Neurosurgery, 55:840-850, 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
Recurrence
24%
27%

41. 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
MVD in Multiple Sclerosis Broggi et. al.: Neurosurgery, 55: ,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”.

43. 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 81:57-64, 2003

44. Percutaneous Procedures
Radiofrequency thermal coagulation
Glycerol rhizolysis
Balloon compression

46. Needle Insertion

47. Radiofrequency Lesion

48. Glycerol Injection Contrast in trigeminal cistern
Contrast under temporal lobe

49. 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 38:865—871, 1996

51. Trigeminal Nerve Complications
MVD
PRFTG
PGR
PBC
Numbness 2 98 60 72
Dysesthesia
0.5 24 16 19 AD
1.5
1.8
0.1
Corneal reflex
0.05 7
3.7
Keratitis 1
Motor
1.7 66
Taha J, Tew J: Neurosurgery 38:865—871, 1996

52. Radiosurgery for TN

53. 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 ± 4.3% -
5 years ± 9.3% 37.7 ± 15.6%

54. GKR

55. GKR

56. GKR

57. 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

58. 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 (Eagle’s syndrome)

59. GPN vs. TN TN 70-100x more common than GPN
GPN shows no sex predilection
TN slightly more common in women (3:2)
GPN occurs more commonly on the left side (3:2)
TN more common on the right (5:3)
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

60. 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

61. 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.