Severe Refractory Obsessive Compulsive Disorder and Depression: Should We Consider Stereotactic Neurosurgery?

Abstract

Functional neurosurgery involves modulation of activity within neural circuits that drive pathological activity. Neurologists and neurosurgeons have worked closely together, advancing the field for over a century, such that neurosurgical procedures for movement disorders are now accepted as "standard of care", benefiting hundreds of thousands of patients. As with movement disorders, some neuropsychiatric illnesses, including obsessive compulsive disorder and depression, can be framed as disorders of neural networks. Over the past two decades, evidence has accumulated that stereotactic neurosurgery can help some patients with mental disorders. Nevertheless, despite the availability of class I evidence for some interventions, there is a huge mismatch between the prevalence of severe refractory mental disorders and the number of referrals made to specialised functional neurosurgery services. This paper examines the historical trajectory of neurosurgery for movement and mental disorders. A review of neurosurgical techniques, including stereotactic radiofrequency ablation, gamma knife, deep brain stimulation, and magnetic resonance imaging guided focused ultrasound, explains the high degree of safety afforded by technological advances in the field. Evidence from clinical trials supporting functional neurosurgery for mental disorders, including obsessive compulsive disorder and depression, is presented. An improved understanding of modern functional neurosurgery should foster collaboration between psychiatry and neurosurgery, providing hope to patients whose symptoms are refractory to all other treatments.

Keywords: deep brain stimulation; focused ultrasound; major depression; obsessive compulsive disorder; stereotactic ablation; stereotactic neurosurgery.

Figure 1

Stereotactic radiofrequency ablation thalamotomy for tremor. Hand drawn spiral before (left) and after (right).

Figure 2

Stereotactic surgery. A stereotactic frame is securely applied to the head (left). A fiducial box is attached to the frame before magnetic resonance images (MRI) are obtained (center). A stereotactic T2 weighted axial MRI of the brain (right) demonstrates the brain anatomy as well as the fiducial markers (three white dots at the top and sides of the image. These dots allow precise mathematical calculations to allow extremely accurate neurosurgical planning in 3D space (demonstrated by the red lines and X, Y and Z coordinates).

Figure 3

Deep brain stimulation (DBS). DBS simulation with electrode in Orange, red nucleus in red, substantia nigra in blue and subthalamic nucleus in green. The electrical field is depicted as a small purple sphere around the electrode and within the subthalamic nucleus. Several parameters of the electrical field can be adjusted, such as its shape, voltage, pulse width, and frequency, to tailor its influence on the surrounding anatomy, maximizing beneficial effects and minimizing side effects. (Figure courtesy of Dr Marie Krueger).

Figure 4

Comparison of stereotactic ablation with temporal lobectomy. Coronal magnetic resonance images following radiofrequency cingulotomy (left), radiofrequency capsulotomy (center), and temporal lobectomy for temporal lobe epilepsy (right). The lesions and resection area are marked by an arrowhead in each case. The extremely small size of the stereotactic lesions when compared to the extensive temporal lobe resection can be appreciated.