Amygdalotomy

[1][2][3][4] The practice of medical amygdalotomy typically involves the administration of general anesthesia and is achieved through the application of cranial stereotactic surgery to target regions of the amygdala for surgical destruction.

[3][11] Since the early 1900s there has been an accumulation of experimental evidence to demonstrate the role of the limbic system, specifically the amygdala complex in mediating emotional expressions of fear and anger.

Similarly, clinical studies in humans have revealed the close etiological role of temporal lobe structures, particularly the limbic system and the amygdala in mediating fear and rageful behavior.

The clinical practice of amygdalotomy in humans is commonly implemented under the stereotactic frame, with varying techniques used to destroy the amygdala, ranging from radiofrequency, mechanical destruction and the injection of oil, wax, and alcohol.

[3] In spite of these methodological differences, most published accounts of human amygdalotomy have indicated beneficial outcomes in reducing the intensity and frequency of aggressive behaviors.

[11] Professor Hirotaro Narabayashi and his colleagues were the first researchers to carry out stereotactic amygdalotomy for the treatment of abnormal aggression and hyperexcitability in a series of 60 patients with psychological disturbances.

[3][11] The procedure was performed under a stereotactic frame devised by Professor Narabayashi and involved the administration 0.6-0.8ml mixture of oil-wax to destroy the lateral groups of the amygdala nucleus, localized via pneumoencephalography.

[3] Around the same time, Hatai Chitanondh utilized a slightly different technique of stereotactic amygdalotomy using an injection of an olive oil mixture to induce lesions to mechanically block signals in the amygdala.

[11] The development of MRI technology in the recent 20th century has enabled a more accurate and efficient process of amygdalotomy, with easier localization of amygdala regions during neuro-navigation as well as the use of advanced radiofrequency generating electrode to induce surgical lesions.

Using reliable and objective methods of evaluation, Heimburger and colleagues found that in patients who did not respond to non-surgical therapy, amygdalotomy was effective, with both conditions of uncontrolled conduct disorder and seizures seeming improved after surgery.

Additionally, the researchers found some evidence for the retention of positive outcomes in one-third of the patients, which were not limited to improvements in rageful behaviour but also included a decrease in the overall frequency of seizures.