Radiation “knifing” trigeminal nerve appears to be a safe and effective alternative in Trigeminal Neuralgia – though used more in people unable to tolerate microvascular decompression.
No Shinkei Geka. 2013 Dec;41(12):1065-74.
[Gamma knife radiosurgery for trigeminal neuralgia: analysis of a multi institutional study].[Article in Japanese]
Takanashi M, Fukuoka S, Ozaki Y, Satou K, Oikawa M, Nakamura H.
- Often a back up plan as 369 had prior percutaneous nerve block and 173 patients had undergone microvascular decompression(MVD) prior to GKRS
- Gamma Knife radiosurgery [GNRS] is done in Winnipeg, Manitoba near here.
- I can only give you info written in abstract… japanese is a little rusty :)
- 689 patients
- 69.4% targeted at the nerve root entry zone(REZ)and for 20.4% of patients targeted at the retrogasserian region(RGR).
- The target dose of the GKRS varied from 70 to 90 Gy(mean:77.8Gy)
- Initially – 66% excellent or good control(pain free), 15% fair control(more than 50% relief), and 19% (192) failed
- After 3 years – 64% were pain free and 80% > 50% pain relief.
- Alternatives for faliures? – after 4 years – 37 patients underwent additional GKRS, 36 MVD (microvascular decompression) and 36 percutaneous nerve block. – that would be 99/689 = 15%
- Tolerable numbness (hypoesthesia or paresthesia) in 11%, bothersome numbness in1%.
- No new (deafferentation) pains.
- 1% dry eye, but no eye lesions found.
Comment – I would think if well enough, microvascuolar decompression should be tried first, and then if it fails, then GNRS could be tried. However, there is over a 50% chance that gamma knife will do the job so in more fail cases, it is acceptable treatment.