PMID: 9609299 | Gamma knife radiosurgery for thalamotomy

[janet paterson <janet313@xxxxxxxxxxx>]

Gamma knife radiosurgery for thalamotomy in parkinsonian tremor:
a five-year experience.

OBJECT: Certain patients, for example, elderly high-risk surgical patients, may 
be unfit for radiofrequency thalamotomy to treat parkinsonian tremor.

Some patients, when given the opportunity, may choose to avoid an invasive 
surgical procedure.

The authors retrospectively reviewed their experience using gamma knife 
radiosurgery for thalamotomies in this patient subpopulation:
1) to determine the efficacy of the procedure;
2) to see if there is a dose-response relationship;
3) to review radiological findings of radiosurgical lesioning; and
4) to assess the risks of complications.

METHODS: Radiosurgical nucleus ventralis intermedius thalamotomy using the 
gamma knife unit was performed to make 38 lesions in 24 men and 10 women 
(median age 73 years, range 58-87 years) over a 5-year period.

A median radiation dose of 130 Gy (range 100-165 Gy) was delivered to 38 nuclei 
(four patients underwent bilateral thalamotomy) using a single 4-mm collimator 
following classic anatomical landmarks.

29 lesions were made in the left nucleus ventralis intermedius thalamus for 
right-sided tremor.

Patients were followed for a median of 28 months (range 6-58 months).

Independent neurological evaluation of tremor based on the change in the 
Unified Parkinson's Disease Rating Scale tremor score was correlated with 
subjective patient evaluation.

Comparison was made between a subgroup of patients in whom "low-dose" lesions 
were made (range 110-135 Gy, mean 120 Gy) and those in whom "high-dose" lesions 
were made (range 140-165 Gy, mean 160 Gy) for purposes of dose-response 
information.

 4 (10.5%) thalamotomies failed
 4 (10.5%) produced mild improvement
11 (29.0%) produced good improvement
10 (26.0%) produced excellent relief of tremor
 9 (24.0%) the tremor was eliminated completely.

The median time to onset of improvement was 2 months (range 1 week-8 months).

Concordance between an independent neurologist's evaluation and that of the 
patient was statistically significant (p < 0.001).

Two patients who underwent unilateral thalamotomy experienced bilateral 
improvement in their tremor.

There were no neurological complications.

There was better tremor reduction in the high-dose group than in the low-dose 
group (p < 0.04).

CONCLUSIONS: Although less effective than other stereotactic techniques, gamma 
knife radiosurgery for thalamotomy offers tremor control with minimal risk to 
patients unsuited for open surgery.


J Neurosurg 1998 Jun;88(6):1044-9
Duma CM, Jacques DB, Kopyov OV, Mark RJ, Copcutt B, Farokhi HK
Good Samaritan Hospital, Los Angeles, California 90017, USA.
PMID: 9609299, UI: 98270462

<>

janet paterson
52 now / 41 dx / 37 onset
613 256 8340 po box 171 almonte ontario canada K0A 1A0
a new voice: <>
<janet313@xxxxxxxxxxx>