By Mary Beth Nierengarten
CHICAGO -- May 1, 2008 -- Patients suffering from obsessive-compulsive disorder (OCD) unresponsive to traditional medical and psychological therapies may benefit from surgical intervention with deep-brain stimulation (DBS), according to a study presented here at the 76th Annual Meeting of the American Association of Neurological Surgeons (AANS).
Lead author Ali R. Rezai, MD, Jane & Lee Seidman Chair in Functional Neurosurgery, and Director, Center for Neurological Restoration, Cleveland Clinic, Cleveland, Ohio, reported here on April 28 on the first 26 patients treated with DBS at 4 centres between 1998 and 2003.
All patients in the study were deemed to have severe OCD as measured by a Yale-Brown Obsessive-Compulsive Scale (YBOCS) score greater than 28 and had suffered from OCD for 8 to 14 years (mean of 22 +-1.5 years). All subjects had failed to achieve successful treatment with prior medication (at least 2 adequate drug regimens) and behavioural therapy (at least 20 sessions). The patients were followed for a mean of 24 years.
Using standard-frame stereotactic techniques, custom DBS leads were implanted bilaterally in all patients in the ventral anterior limb or the internal capsule and adjacent ventral striatum (VC/VS). The initial site of VC/VS was based on anterior capsulotomy and later moved to a more posterior location. A second procedure under general anesthesia was performed to implant programmable pulse generators, which were subsequently programmed in an outpatient setting by psychiatrists.
The primary outcome in this study was continuous measurements of the YBOCS score over time. A response to DBS (decline in the severity of OCD) over time was characterised as a full response for those who had at least a 35% YBOCS decrease from preimplantation baseline; a partial response for those who had at least a 25% YBOCS decrease but less than 35% reduction; and no response for those who had less then 25% YBOCS decrease.
At 36 months after DBS, the study found a significant decrease in the mean YBOCS score for the 24 patients who reached a YBOCS score of 20.9 +-2.4 (P = .002). Patients considered full responders (>35% YBOCS decrease) increased from 28% at 1 month following DBS to 61.5% (16/26) at last follow-up. Patients who did not respond (<25% YBOCS decrease) declined from 68% (17/25) at 1 month to 27% at last follow-up.
According to Dr. Rezai, these results show progressive improvement in YBOCS scores over time, even in the nonresponders group, which showed some improvement.
The study also found that patients treated later in the series, when modifications to technique were used, had even better response scores: 33.3% were full responders in the first series of patients treated and 75% in the last series of patients treated.
Overall, the treatment was well tolerated, with most adverse effects being only temporary.
The authors concluded that DBS, conducted in the setting of a multidisciplinary team, is safe and effective for severely disabled patients with OCD refractory to previous treatments.
Subjects were excluded from this study if they had a current or past history of a psychotic disorder, had substance-abuse problems, were at imminent risk of suicide, had a current clinically significant neurological disorder or medical illness, or had had a manic episode within the 3 years preceding the study.
To date, DBS is used primarily as an adjuvant to ongoing medical and behavioural therapies that patients remain on after implantation. Although most patients can taper their medication dose, said Dr. Rezai, most stay on medication.
Of the 2% to 3% of patients in the United States diagnosed with OCD, at least 10% remain refractory to treatment and remain markedly impaired in their ability to complete everyday activities. "These are patients who are very severely disabled from OCD for many years and can be described as in end-stage disease," noted Dr. Rezai.
[Presentation title: Deep Brain Stimulation of the Ventral Internal Capsule/Ventral Striatum for Obessive-Compulsive Disorder: World-Wide Experience. Abstract 621]
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