Historical Background

John Fothergill – 1773

Charles Bell – 1829

Walter Dandy –1934

Images from Prasad, et al.

Criteria for Diagnosis

Paroxsymal, usually unilateral attacks of facial pain in one or more trigeminal divisions lasting <1 sec – 2 min

At least one of the following: 1) Intense, sharp, superficial or stabbing quality, 2) Precipitation by “triggers” 3) Relative absence of symptoms between attacks

Stereotyped patterns of attacks within individual patients

No objective neurologic deficit

No other identified causes for facial pain

The International Classification of Headache Disorders, 2nd Ed.

Classification of Facial Pain

Burcheil, KJ. “A New Classification for Facial Pain.” Neurosurgery. 2003

Treatment Options

Medication

Percutaneous Rhizotomy (Glycerol, Balloon, or RFA)

Stereotactic Radiosurgery (1951)

Microvascular Decompression

Gamma knife for Tic

Safe and effective

Non-invasive

Drawbacks: Durability and trigeminal dysfunction

MCG Patient Demographics

318 Patients treated, Mean follow up 16.25 months (3-120 mo)

33.6% Male/66.4% Female

81.4% Caucasian/15.1% African American

No Prior – 76.7%

MVD – 4.4%

GKRS – 0.6%

Other – 18.2%

Pain Characteristics

289 (90.9%) with TN1 or TN2

51.8% Right/47.1% Left/1.1% Bilateral

Treatment Protocol

80.7 Gy mean maximum dose to nerve (70-90Gy)

Single Shot (96.8%)

4mm collimator (100%)

82.7% Model B

Response to Gamma

Trigeminal Neuralgia Type 1 and Type 2

91.2% with good/excellent outcomes (Class I-III)

60.3% with pain-free outcomes

8.8% with little/no response to treatment (Class IV-V)

PFOM 36.3%

PFWM 24%

PWM 30.9%

NR (IV/V) 8.8%

Neuropathy, MS, and Repeat GKRS

Good/Excellent No Response Pain-Free n

Neuralgia 91.2% 8.8% 60.3% 204

Neuropathy 57.1% 42.9% 21.4% 14

MS 77.8% 22.2% 66.7% 9

Repeat GKRS 91.7% 8.3% 37.5% 24

Subgroup Comparison

Good/Excellent Pain Freedom p-value p-value

Neuralgia vs Neuropathy <0.001 <0.005 Neuralgia vs MS NS NS Neuralgia vs Repeat GKRS NS <0.05 Age <65 vs >65 NS <0.01 Smoking NS NS

The neuropathy group was less likely to experience a Good/Excellent outcome, or experience a pain-free outcome than the neuralgia group

The Repeat GKRS group was less likely to achieve a pain free outcome, but not less likely to respond to therapy than patients undergoing initial treatment

Patients older than 65 were more likely to experience a pain free response than patients less than 65

Retreatment Response

Retreatment mean max dose 69.8 Gy

The retreatment group was less likely to achieve a pain free response than the initial treatment group on second treatment (p < 0.05)

Good/Excellent Pain-Free

No Response n

Neuralgia 91.2 60.3 8.8 204

First Tx 94 48 6 50

Second Tx 91.7 37.5 8.3 24

Conclusions

Gamma knife radiosurgery is an effective option for the treatment of medically refractory trigeminal neuralgia

Durability is likely the greatest weakness of this treatment modality

Useful for patients with MS as well as Neuropathy, although efficacy may be decreased in these settings

Repeat GKRS is possible after initial treatment failure, but a pain free response may be less likely

Thank you

Special thanks to Christina Hamilton and Dr. Vender

Thank you for your attention