W rITH the contemporary development of surgical methods of treating the symptoms of painful, psychiatric, and basal ganglion disorders, the neurosurgcon is frequently called upon to produce a focal destructive lesion in the nervous system. The universal and obvious objective is to create a localized lesion in the desired area with no damage to adjacent or intervening tissues. Recorded experiences of neurosurgeons attest to the fact that this ideal has not yet been attained. Paraparesis and bladder dysfunction following anterolateral chordotomy, vegetation following prefrontal lobotomy, and hemiplegia following surgical treatment of basal ganglion disorders are examples of damage to adjacent tissues known to all neurosurgeons. Damage to blood vessels (including those within the site of the lesion) at time of operation may increase the operative morbidity and render it impossible to evaluate the effect of a focal ablation. Stereotaxically placed electrocoagulative lesions have frequently resulted in death from hemorrhage.As the result of animal experimentation 1-4,6 we believe that the use of ultrasound in making human focal destructive lesions will overcome some of these objections. A focussed beam of ultrasound can be used to produce selective, accurately localized lesions in the central nervous system which are quantitatively reproducible from one animal to another. Discrete lesions can be produced without destruction of blood vessels. A lesion in the depths of the brain can be effected without disturbance of intervening tissue. Accurate localization is accomplished by focussing a fine beam of ultrasound in the region to be treated. The nature of the destruction depends upon the intensity and duration of the exposure.The term "ultrasound" refers to sounds whose frequency (pitch) is above the range of human audibility (15,000 to ~0,000 cycles per second). M:ost of the work up to the present time has been accomplished at a frequency of one * Partially supported by Contract Nonr 336(00), NR 119-075 with the Physiology Branch of the Office

No abstract

No abstract

No abstract

No abstract