Impact of parameters of radiofrequency coagulation on volume of stereotactic lesion in pallidotomy and thalamotomy.
BACKGROUND
One of the many reasons why lesional surgery for movement disorders has been more or less abandoned may have been the difficulty in predicting the shape and size of the stereotactic radiofrequency (RF) lesion.


OBJECTIVE
To analyse the contribution of various RF coagulation parameters towards the volume of pallidotomies and thalamotomies.


METHODS
The relationship between temperature of coagulation, length of coagulated area and duration of coagulation on the one hand, and lesion volume on the other was retrospectively evaluated. Lesion diameters were measured on stereotactic thin-slice CT and MRI scans, and volumes of lesions were calculated concerning 36 pallidotomies and 14 thalamotomies in 46 patients who were operated using the same RF generator and same RF electrode.


RESULTS
The coagulation temperature, length of coagulated area and duration of coagulation were all correlated to the lesion volume. However, for a given length of coagulated area, the lesion´s size was most strongly influenced by the temperature. Despite this clear correlation, and the relatively homogenous coagulation parameters, the lesions' volumes were markedly scattered.


CONCLUSIONS
The volume of the stereotactic RF lesions could be correlated with the coagulation parameters, especially the temperature, at a group level, but could not be predicted in individual patients based solely on the RF coagulation parameters.
Department of Neurosurgery, Nara Medical University, Kashihara, Japan.
Hidehiro
H
Hirabayashi
Marwan I
MI
Hariz
Karin
K
Wårdell
Patric
P
Blomstedt
D000368:Aged; D001777:Blood Coagulation / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D053860:Pallidotomy / Q000379:methods*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D013788:Thalamus / Q000473:pathology / Q000601:surgery*