Deep Brain Stimulation for Intractable Obsessive-Compulsive Disorder and Treatment-Resistant Depression

In deep brain stimulation (DBS), a neurostimulation device is implanted to generate electrical fields in targeted deep brain regions in order to affect circuits associated with neuropsychiatric illness for potential therapeutic benefit. The development of DBS has followed a decades-long history of psychiatric neurosurgery, with advances in pacemakers and spinal neurostimulation devices allowing for the use of DBS in the treatment of neuropsychiatric disorders. Currently, deep brain stimulation for psychiatric illness has been approved by the U.S. Food and Drug Administration for the treatment of intractable obsessive-compulsive disorder, through a Humanitarian Device Exemption. The use of DBS for treatment-resistant depression is another promising application of this technology. Several potential targets of DBS have shown promise for treating neuropsychiatric illness, but few have demonstrated efficacy in randomized controlled trials. Future directions for DBS research will likely include modified trial designs, refined targets, the use of tractography for more specific and individualized targeting, and development of closed-loop DBS.

Deep Brain Stimulation as Clinical Innovation: An Ethical and Organizational Framework to Sustain Deliberations About Psychiatric Deep Brain Stimulation

Deep brain stimulation (DBS) for psychiatric disorders needs to be investigated in proper research trials. However, there are rare circumstances in which DBS could be offered to psychiatric patients as a form of surgical innovation, therefore potentially blurring the lines between these research trials and health care. In this article, we discuss the conditions under which surgical innovation may be accepted as a practice falling at the frontiers of standard clinical care and research per se. However, recognizing this distinction does not settle all ethical issues. Our article offers ethical guideposts to allow clinicians, surgical teams, institutions, and institutional review boards to deliberate about some of the fundamental issues that should be considered before surgical innovation with psychiatric DBS is undertaken. We provide key guiding questions to sustain this deliberation. Then we review the normative and empirical literature that exists to guide reflection about the ethics of surgical innovation and psychiatric DBS with respect to general ethical questions pertinent to psychiatric DBS, multidisciplinary team perspectives in psychiatric DBS, mechanisms for oversight in psychiatric DBS, and capacity and consent in psychiatric DBS. The considerations presented here are to recognize the very specific nature of surgical innovation and to ensure that surgical innovation in the context of psychiatric DBS remains a limited, special category of activity that does not replace appropriate surgical research or become the standard of care based on limited evidence.

ABBREVIATIONS

DBS, deep brain stimulationIRB, institutional review boardOCD, obsessive-compulsive disorder.

Consensus on guidelines for stereotactic neurosurgery for psychiatric disorders

BACKGROUND

For patients with psychiatric illnesses remaining refractory to 'standard' therapies, neurosurgical procedures may be considered. Guidelines for safe and ethical conduct of such procedures have previously and independently been proposed by various local and regional expert groups.

METHODS

To expand on these earlier documents, representative members of continental and international psychiatric and neurosurgical societies, joined efforts to further elaborate and adopt a pragmatic worldwide set of guidelines. These are intended to address a broad range of neuropsychiatric disorders, brain targets and neurosurgical techniques, taking into account cultural and social heterogeneities of healthcare environments.

FINDINGS

The proposed consensus document highlights that, while stereotactic ablative procedures such as cingulotomy and capsulotomy for depression and obsessive-compulsive disorder are considered 'established' in some countries, they still lack level I evidence. Further, it is noted that deep brain stimulation in any brain target hitherto tried, and for any psychiatric or behavioural disorder, still remains at an investigational stage. Researchers are encouraged to design randomised controlled trials, based on scientific and data-driven rationales for disease and brain target selection. Experienced multidisciplinary teams are a mandatory requirement for the safe and ethical conduct of any psychiatric neurosurgery, ensuring documented refractoriness of patients, proper consent procedures that respect patient's capacity and autonomy, multifaceted preoperative as well as postoperative long-term follow-up evaluation, and reporting of effects and side effects for all patients.

INTERPRETATION

This consensus document on ethical and scientific conduct of psychiatric surgery worldwide is designed to enhance patient safety.

Cerebral venous infarction: a potentially avoidable complication of deep brain stimulation surgery

OBJECT

Despite numerous reports on the morbidity and mortality of deep brain stimulation (DBS), cerebral venous infarction has rarely been reported. We present four cases of venous infarct secondary to DBS surgery.

METHODS

The diagnosis of venous infarction was based on 1) delayed onset of new neurologic deficits on postoperative day 1 or 2; 2) significant edema surrounding the superficial aspect of the implanted lead, with or without subcortical hemorrhage on CT scan.

RESULTS

Four cases (0.8% per lead, 1.3% per patient) of symptomatic cerebral venous infarction were identified out of 500 DBS lead implantation procedures between July 2002 and August 2009. All four patients had Parkinson's disease. Their DBS leads were implanted in the subthalamic nucleus (n = 2), and the globus pallidus internus (n = 2). Retrospective review of the targeting confirmed that the planned trajectory passed within 3 mm of a cortical vein in two cases for which contrast-enhanced preoperative magnetic resonance (MR) imaging was available. In the other two cases, contrasted targeting images were not obtained preoperatively.

CONCLUSION

Cerebral venous infarction is a potentially avoidable, but serious complication. To minimize its incidence, we propose the use of high-resolution, contrast-enhanced, T1-weighted MR images to delineate cerebral venous anatomy, along with careful stereotactic planning of the lead trajectory to avoid injury to venous structures.

Twenty-five years of deep brain stimulation: celebrations and apprehensions

The year 2012 marks the 25th anniversary of the birth of modern deep brain stimulation (DBS), which was introduced by Benabid et al in 1987, initially to treat tremor with DBS of the ventral intermediate nucleus of the thalamus. The subsequent extension of DBS to the subthalamic nucleus (STN), demonstrating its efficacy on virtually all symptoms of advanced Parkinson's disease (PD), sparked an era of intense clinical and research activities, eventually transcending PD and movement disorders to encompass mood and mind. Investigations of the role of DBS in a variety of neurological, psychiatric, cognitive, and behavioral conditions is ongoing. Serendipitous discoveries and advances in functional imaging are providing "new" brain targets for an increasing number of pathologies. Toward the end of this quarter of a century of DBS, there have been some indications that the field may be at risk of gliding down a slippery slope, reminiscent of the excesses of the old-era DBS. Although there are many reasons this year to celebrate the achievements of 25 years of modern DBS, there are also reasons to fear the opening of a new Pandora's box.

Deep brain stimulation between 1947 and 1987: the untold story

Deep brain stimulation (DBS) is the most rapidly expanding field in neurosurgery. Movement disorders are well-established indications for DBS, and a number of other neurological and psychiatric indications are currently being investigated. Numerous contemporary opinions, reviews, and viewpoints on DBS fail to provide a comprehensive account of how this method came into being. Misconceptions in the narrative history of DBS conveyed by the wealth of literature published over the last 2 decades can be summarized as follows: Deep brain stimulation was invented in 1987. The utility of high-frequency stimulation was also discovered in 1987. Lesional surgery preceded DBS. Deep brain stimulation was first used in the treatment of movement disorders and was subsequently used in the treatment of psychiatric and behavioral disorders. Reports of nonmotor effects of subthalamic nucleus DBS prompted its use in psychiatric illness. Early surgical interventions for psychiatric illness failed to adopt a multidisciplinary approach; neurosurgeons often worked "in isolation" from other medical specialists. The involvement of neuro-ethicists and multidisciplinary teams are novel standards introduced in the modern practice of DBS for mental illness that are essential in avoiding the unethical behavior of bygone eras. In this paper, the authors examined each of these messages in the light of literature published since 1947 and formed the following conclusions. Chronic stimulation of subcortical structures was first used in the early 1950s, very soon after the introduction of human stereotaxy. Studies and debate on the stimulation frequency most likely to achieve desirable results and avoid side effects date back to the early days of DBS; several authors advocated the use of "high" frequency, although the exact frequency was not always specified. Ablative surgery and electrical stimulation developed in parallel, practically since the introduction of human stereotactic surgery. The first applications of both ablative surgery and chronic subcortical stimulation were in psychiatry, not in movement disorders. The renaissance of DBS in surgical treatment of psychiatric illness in 1999 had little to do with nonmotor effects of subthalamic nucleus DBS but involved high-frequency stimulation of the very same brain targets previously used in ablative surgery. Pioneers in functional neurosurgery mostly worked in multidisciplinary groups, including when treating psychiatric illness; those "acting in isolation" were not neurosurgeons. Ethical concerns have indeed been addressed in the past, by neurosurgeons and others. Some of the questionable behavior in surgery for psychiatric illness, including the bygone era of DBS, was at the hands of nonneurosurgeons. These practices have been deemed as "dubious and precarious by yesterday's standards."

Identification and management of deep brain stimulation intra- and postoperative urgencies and emergencies

Deep brain stimulation (DBS) has been increasingly utilized for the therapeutic treatment of movement disorders, and with the advent of this therapy more postoperative urgencies and emergencies have emerged. In this paper, we will review, identify, and suggest management strategies for both intra- and postoperative urgencies and emergencies. We have separated the scenarios into 1--surgery/procedure related, 2--hardware related, 3--stimulation-induced difficulties, and 4--others. We have included ten illustrative (and actual) case vignettes to augment the discussion of each issue.

The role of imaging in the surgical treatment of movement disorders

Functional neurosurgery involves precise surgical targeting of anatomic structures to modulate neurologic function. From its conception, advances in the surgical treatment of movement disorders have been intertwined with developments in medical imaging, culminating in the use of stereotactic magnetic resonance imaging (MRI). Meticulous attention to detail during image acquisition, direct anatomic localization, and planning of the initial surgical trajectory allows the surgeon to reach the desired anatomic and functional target with the initial trajectory in most cases, thus reducing the need for multiple passes through the brain, and the associated risk of hemorrhage and functional deficit. This philosophy is of paramount importance in a procedure that is primarily aimed at improving quality of life. Documentation of electrode contact location by means of stereotactic imaging is essential to audit surgical targeting accuracy and to further the knowledge of structure-to-function relationships within the human brain.