Neuromodulation Surgery for Psychiatric Disorders

Excerpt

Despite the advances in pharmacotherapy for treating some psychiatric disorders like anxiety disorders, obsessive-compulsive disorder, depression, and schizophrenia, many patients become refractory and will not respond to pharmacologic treatments. Clinicians are beginning to reconsider neuromodulation surgery as a last resort for the treatment of these patients. Neurosurgical interventions aimed at treating psychiatric disorders are grouped into destructive (ablative psychosurgery) or selective stimulation (neuromodulation psychosurgery). Neuromodulation surgery involves implanting a device in the brain that modulates the neural networks within the brain.

The use of surgery for the treatment of psychiatric diseases is not a new concept. Historically, the concept of psychosurgery always raised general skepticism and stigma because of the way that it was used in the past with a high rate of complications and mortalities, but usually with little improvement in patients’ functionality. In 1881, Gottlieb Burckhardt, a Swiss psychiatrist, reported on six patients that he performed surgery to treat aggressive behavior and hallucinations with partial results. Three decades later, Puusepp operated in 1910 on three manic-depressive patients by interrupting the frontal fibers to the parietal cortex. Fulton and Jacobsen's classical experiments on two chimpanzees that received frontal lobe surgical ablation to improve neurotic behaviors were an inspiration for subsequent human ablative procedures. In 1935, a Portuguese neurologist named Egas Moniz first introduced a surgical procedure called prefrontal leucotomy. Moniz believed that abnormal connections to the frontal lobe caused some psychiatric problems and that surgically removing the white fibers connecting the frontal lobe with the rest of the brain will help mental health conditions. Moniz technique was later widely utilized in Europe and the United States. Moniz was awarded the Nobel Prize in 1949 for his contributions. In the United States, prefrontal leucotomy was initially used, but modified by an American neurosurgeon named Walter Freeman, who developed a transorbital leucotomy procedure. Unlike the original lobotomy that involved an open surgery, transorbital leucotomy was a minor surgery. It lasted about 10 to 20 minutes and aimed at separating the frontal lobe from the thalamus by accessing the brain through the back of the orbits with a sharp instrument similar to an ice pick. Clinicians often used this treatment even though, at the time, there was not much data to evaluate the effectiveness of this method, and because of the lack of alternative treatment for patients who had debilitating mental health problems. Later, retrospective studies showed that while Dr. Freeman's approach helped calmed some severely agitated patients, many ended up with numerous complications.

In the late 1950s, pharmacotherapy was introduced and changed the approach in treating psychiatric conditions. Chlorpromazine was the first U.S. Food and Drug Administration approved psychotropic drug. While pharmacotherapy led to psychosurgery quietus, physicians laid the groundwork for the development of stereotactical microsurgery techniques. Speigel and Wycis developed the concept of stereotactic surgery to perform precise ablative lesions in deep areas of the brain in 1947. In 1962, Foltz and White used this technique for stereotactic anterior cingulotomy. Furthermore, the rapid development of numerous modalities helped to understand the structure and function of the brain. These new advances, coupled with the frustrations of the significant percentage of patients not responding to pharmacotherapy and positive results in the use of neuromodulation surgery like deep brain stimulation (DBS) in the treatment of movement disorders like Parkinson's disease, leaded clinicians to revisit the use of neuromodulation surgery for the treatment of psychiatric disorders. However, professionals debated whether these techniques will be used only as a last resort for the treatment of refractory psychiatric symptoms, or if they will be used for other purposes like to modify the cognition of healthy individuals. Ethical requirements and guidelines for the procedures began to appear in physician's societies.