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Targeting the brain's anterior capsule (OCD) with precise, high-intensity radiation led to dramatic improvements in patients with severe obsessive-compulsive disorder (OCD), according to results of a small clinical trial.

Reductions in objective symptom scores in three patients ranged from 29% to 79% after anterior capsulotomy performed with a "gamma knife" radiotherapy system, according to Douglas Kondziolka, MD, and colleagues at the University of Pittsburgh.

"We found that radiosurgical anterior capsulotomies can provide benefit in patients with extreme obsessive compulsive disorder," Kondziolka and co-authors reported in the January issue of Neurosurgery.

"Such benefits led to improvement in social and thought behaviors as well as in physical manifestations of the disease," the researchers added -- with no apparent adverse effects after as long as 4.5 years of follow-up.

However, they pointed out that detailed neurocognitive testing was performed in only one of their patients. They also noted that deep brain stimulation has well-documented efficacy in severe OCD, although it has practical drawbacks.

Consequently, Kondziolka and colleagues recommended a head-to-head trial of deep brain stimulation and radiosurgery for the condition.

Previous MRI studies have identified abnormalities in the anterior capsule that correlate strongly with OCD symptoms. A number of procedures intended to alter neuronal firing in the region have been tried with varying degrees of success.

Deep brain stimulation has been approved by the FDA for severe OCD that does not respond to drug therapy, and it has the advantage of being reversible and adjustable, Kondziolka and colleagues observed.

But lead placement is difficult and entails some risk, and the implanted pulse generators must be replaced periodically. Also, Kondziolka and colleagues pointed out, deep brain stimulation requires programming and monitoring over a period of months to optimize the effect.

In contrast, they wrote, gamma knife surgery is a one-time, noninvasive procedure with no follow-up management or adjustment required -- and hence carries a lower overall cost.

Other small, uncontrolled trials have yielded encouraging results for radiosurgery.

The three patients receiving the procedure at the University of Pittsburgh all had been evaluated by at least two psychiatrists, who recommended a surgical therapy after drug treatment had failed to relieve symptoms adequately. Patients then had to formally request the procedure.

Patients' ages ranged from 37 to 55. Their symptoms included counting and grooming rituals, extreme concerns about cleanliness, and compulsive skin picking and gouging leading to a persistent open wound.

Two of the patients had baseline scores on the 40-point Yale-Brown Obsessive Compulsive Scale of 39 and the third patient had a score of 34.

The gamma knife procedure delivered total doses of 140 to 150 Gy in a single day, creating two 4-mm isocenters in the anterior limb of the internal capsule at the mid-putaminal point, as located by stereotactic MRI . The two lesions were intended to create an oval with the base at the capsule's ventral side.

Patients went home the same day as the procedure and were evaluated for efficacy after 28 to 55 months.

The patient with the baseline Yale-Brown score of 34 had a score of 24 at follow-up. The other two had scores of 9 and 18, Kondziolka and colleagues reported.

The most dramatic improvement was in the patient with chronic skin picking, whose open wound had healed at 18 months of follow-up.

The authors noted that this patient would not have been eligible for deep brain stimulation under terms of the FDA's approval in OCD, in part because it could compromise wound healing.

They noted, however, that their trial was very small and the long-term efficacy and safety of radiosurgical anterior capsulotomy using the gamma knife remain unknown -- also the case for deep brain stimulation and other procedure-based treatments for OCD.

Source: Neurosurgery

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