Surgery is reserved for the most difficult cases of OCD, those that fail to improve after all possible nonsurgical treatments, such as medications, behavioral therapy, and so forth.
The goals of surgery are to make patients more functional and independent, to improve the symptoms of OCD, and, in most cases, to decrease the need for medications, particularly if the medications’ side effects are problematic.
In the past, the most common procedures (capsulotomy, anterior cingulotomy) involved making small lesions in the deep brain structures, such as the cingulate gyrus, the anterior capsule, or other areas of the brain that participate in the limbic system (the fear center of the brain) and its connections. This was done using either high frequency radio waves or with thin wires that had electrodes on them which would burn small portions of brain tissue. These procedures were done with special guidance from information gleaned pre-surgery using computed tomography (CT scan), magnetic resonance imaging (MRI), or other brain scans or testing.
Two main issues are related to the risk of surgery: the destruction of important areas of the human brain and the irreversibility of surgical effects. Older surgical procedures required cutting through healthy parts of the brain, or snaking wires through the brain to the disordered areas, which could also damage the healthy parts.
Currently, the two most promising trends include either making brain lesions with stereotactic radiosurgery (using, for example, a gamma knife) or implanting special deep-brain stimulators that modify brain activity like the lesions do, but without actual destruction of brain tissue.
Radiosurgery, such as with a gamma knife, does not require any incisions and is done on an outpatient basis, making it very attractive for those who want to avoid staying in the hospital. However, even though no instruments are used, radiosurgery, which is also irreversible, still destroys small areas of the brain; the gamma knife does this by directing a beam of radiation at a certain point in the brain without damaging parts of the brain around that point or, amazingly, damaging any of the tissue the radiation must pass through to get to that point.
Deep brain stimulation, on the other hand, does not destroy any tissue, and therefore its effects are reversible as well as adjustable, given that the stimulation may be changed depending on the patient’s response. The procedure of stimulation, however, is more involved and requires implantation of pacemaker-like devices (battery packs) and insertion of electrodes into the brain.
Once the devices are in, a clinician can cause the stimulators to create electrical charges, affecting certain nerves in the brain and having an effect on a person’s thoughts, anxieties, and behaviors. As stimulation increases or decreases, obsessions and compulsions can be measured to see if they increase or decrease. The stimulation can be altered until, theoretically, a person has no, or almost no, OCD symptoms.
Both of these approaches are done primarily in major research and clinical centers; large-scale investigations are currently underway to determine which surgical approach is safest and most effective.