TUESDAY, Dec. 23, 2014 (HealthDay News) -- Though most patients with obsessive-compulsive disorder (OCD) can be successfully treated with medication and therapy, between 10 percent to 20 percent have a form of the illness that doesn't respond to standard care, experts say.

However, patients with this so-called "refractory OCD" do have hope in the form of a type of brain surgery that disables certain brain networks believed to contribute to OCD.

The challenge: to distinguish between patients most likely to benefit from the surgery, known as "dorsal anterior cingulotomy," from those who probably won't.

Now new research, reported in the Dec. 23 online issue of JAMA Psychiatry, suggests that doctors may be able to spot candidates for the surgery by looking at a key structure in the targeted brain region.

In the study, investigators conducted MRI scans of 15 refractory OCD patients, all of whom had undergone cingulotomy surgery.

The team, led by Garrett Banks of Columbia University in New York City, found that only about half (8 patients) had responded positively to the procedure, which involves the short-circuiting of problematic brain networks.

The scans suggest that, in the brain region in question, patients who responded to surgery had different brain structures than those who didn't, according to a journal news release.

"These variations may allow us to predict which patients are most likely to respond to cingulotomy, thereby refining our ability to individualize this treatment for refractory psychiatric disorders," the authors wrote in their study.

In an accompanying editorial, one Dutch expert said such a pre-operative test might save patients unnecessary trauma, and save health care dollars.

"If reliable predictive markers are identified . . . treatments might be offered only to patients with a predicted good outcome, thereby preventing unnecessary costs and [side effects or complications] in the remaining patients," said Dr. Odile van den Heuvel of the VU University Medical Center in Amsterdam.