Neurosurgery for Mental Disorders (NMD)
Intro ECT TMS MST VNS DBS
Brain surgery that promotes behavioural or affective changes in humans is controversial. 1935-1950 saw the use of “frontal lobotomies” to treat psychiatric disorders. This resulted in major personality changes. The surgery was often carried out by inadequately trained surgeons using a crude technique to blindly insert cutting instruments into the brain. There was a high incidence of complications and side effects.
Now-a-days, the technique is more refined, and the term “psychosurgery” has been replaced by the term “neurosurgery for mental disorders”. The patient receives a general anaesthetic. Highly skilled surgeons use a special framework and MRI scans to accurately place the lesions (permanently remove small parts) in the brain. A probe tip is carefully positioned and heated to 70-80 degrees centigrade in order to destroy a part of the brain 8-10mm in diameter. Consent from the patient is essential and modern surgical intervention is for intractable mental disorders when all other treatment has failed.
The brain is complex and made up of lobes, systems and networks. The Limbic System is involved in mood (and emotions).
There are different surgical procedures for depression, all of which relate to the limbic system, including an anterior capsulotomy, an anterior cingulotomy, a limbic leucotomy and a subcaudate tractotomy.
Modern techniques hope to ensure there is no deterioration in intelligence or change in personality or memory. The treatment is irreversible- so accurate placement of the lesions is essential. It is not a cure. It may take 9-12 months to see a clinical improvement and if successful, the patient will need continuing psychiatric support. Approximately a third to a half of patients receiving psychosurgery achieve a response or remission[1].
Side effects that are transient include: urinary incontinence, headache, nausea, confusion, tiredness, infection, agitation, seizures and weight gain. Sustained side effects include: urinary incontinence, headache, epilepsy, intracranial bleed/stroke, suicide.
If performed by experienced surgeons neurosurgery for mental disorders is safe, quick, involves no implants, requires no post-operative adjustment of hardware and it is cheaper than DBS. It also means there are no risks or the expenses of a lifelong implant. It is rarely used in clinical practice.