Notes on Obsessive Compulsive Disorder and Surgical Interventions

Overview of OCD

• Definition: A serious neuropsychiatric condition characterized by intrusive thoughts (obsessions) and the irresistible urge to neutralize these thoughts (compulsions).
• Prevalence:
  • Estimated 2 million people in the U.S. affected.
  • Approximately 200,000 new patients each year.
• Patient Awareness: Many patients are aware of the irrationality of their thoughts but still cannot stop the compulsions.

Treatment Options for OCD

• First-line Treatments:
  • Behavioral Therapy: Exposure and Response Prevention (ERP)
    • Patients think about their obsessions without giving in to compulsions (e.g. touching contaminated surfaces without washing hands).
  • Medications:
    • Usually serotonergic or dopaminergic agents.
• When First-line Treatments Fail:
  • Deep Brain Stimulation (DBS) is considered for refractory cases.

Case Study: DBS for a 40-Year-Old Male with OCD

• Patient History:
  • Suffered from OCD with tics since childhood.
  • Common obsessions included fears of harming himself (e.g., poking his eyes).
  • High score of 30/40 on the Yale-Brown Obsessive Compulsive Scale.
  • Tried multiple treatments: medications, transcranial magnetic stimulation, electroshock therapy, and ERP without success.
• Decision for DBS:
  • Clear diagnosis of OCD and refractory condition led to consent for DBS targeting the anterior limb of the internal capsule.

Surgical Procedure for DBS

• Preoperative Assessments:
  • High-resolution volumetric MRI and CT scans under general anesthesia.
  • Target selection guided by tractographic analysis.
• Targeting Strategy:
  • Two main subdivisions within anterior limb of the internal capsule:
    • Medial segment (thalamus and medial prefrontal cortex)
    • Lateral segment (ventral lateral prefrontal cortex)
  • Identifying anchor points and ensuring engagement of key anatomical regions.

Intraoperative Process

• Use of Stereotactic Head Frame:
  • Local anesthesia for head frame placement, followed by intraoperative CT scan.
• Microelectrode Recording:
  • Placement and confirmation of trajectory.
• DBS Electrode Placement:
  • Stage fashion with the patient typically discharged the next day.

Postoperative Outcomes

• Initial Responses:
  • Patient initially showed improvement at contact 1, but consistent improvement was noted at contact 2 after amplitude was increased to 6 milliamps.
  • Significant reduction in anxiety and return to normal activities (e.g., living independently, socializing, working).
  • Follow-up at six months showed the patient almost free of OCD symptoms.

Conclusion

• Efficacy of DBS:
  • Roughly 60% of patients experience a meaningful response to DBS treatment.
• Multidisciplinary Approach:
  • Emphasizes collaboration between neurosurgeons, neuropsychiatrists, and biomedical engineers to create personalized treatment plans for OCD patients.