Functional stereotactic neurosurgery for psychiatric disorders: an experience in Belgium and The Netherlands

Thirty Years of Global Deep Brain Stimulation: "Plus ça change, plus c'est la même chose"?

BACKGROUND

The advent of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease 30 years ago has ushered a global breakthrough of DBS as a universal method for therapy and research in wide areas of neurology and psychiatry. The literature of the last three decades has described numerous concepts and practices of DBS, often branded as novelties or discoveries. However, reading the contemporary publications often elicits a sense of déjà vu in relation to several methods, attributes, and practices of DBS. Here, we review various applications and techniques of the modern-era DBS and compare them with practices of the past.

SUMMARY

Compared with modern literature, publications of the old-era functional stereotactic neurosurgery, including old-era DBS, show that from the very beginning multidisciplinarity and teamwork were often prevalent and insisted upon, ethical concerns were recognized, brain circuitries and rational for brain targets were discussed, surgical indications were similar, closed-loop stimulation was attempted, evaluations of surgical results were debated, and controversies were common. Thus, it appears that virtually everything done today in the field of DBS bears resemblance to old-time practices, or has been done before, albeit with partly other tools and techniques. Movement disorders remain the main indications for modern DBS as was the case for lesional surgery and old-era DBS. The novelties today consist of the STN as the dominant target for DBS, the tremendous advances in computerized brain imaging, the sophistication and versatility of implantable DBS hardware, and the large potential for research.

KEY MESSAGES

Many aspects of contemporary DBS bear strong resemblance to practices of the past. The dominant clinical indications remain movement disorders with virtually the same brain targets as in the past, with one exception: the STN. Other novel brain targets - that are so far subject to DBS trials - are the pedunculopontine nucleus for gait freezing, the anteromedial internal pallidum for Gilles de la Tourette and the fornix for Alzheimer's disease. The major innovations and novelties compared to the past concern mainly the unmatched level of research activity, its high degree of sponsorship, and the outstanding advances in technology that have enabled multimodal brain imaging and the miniaturization, versatility, and sophistication of implantable hardware. The greatest benefit for patients today, compared to the past, is the higher level of precision and safety of DBS, and of all functional stereotactic neurosurgery.

International Legal Approaches to Neurosurgery for Psychiatric Disorders

Neurosurgery for psychiatric disorders (NPD), also sometimes referred to as psychosurgery, is rapidly evolving, with new techniques and indications being investigated actively. Many within the field have suggested that some form of guidelines or regulations are needed to help ensure that a promising field develops safely. Multiple countries have enacted specific laws regulating NPD. This article reviews NPD-specific laws drawn from North and South America, Asia and Europe, in order to identify the typical form and contents of these laws and to set the groundwork for the design of an optimal regulation for the field. Key challenges for this design that are revealed by the review are how to define the scope of the law (what should be regulated), what types of regulations are required (eligibility criteria, approval procedures, data collection, and oversight mechanisms), and how to approach international harmonization given the potential migration of researchers and patients.

Deep brain stimulation and ablation for obsessive compulsive disorder: evolution of contemporary indications, targets and techniques

Surgical therapy for treatment-resistant obsessive compulsive disorder (OCD) remains an effective option for well-selected patients managed within a multidisciplinary setting. Historically, lesions within the limbic system have been used to control both obsessive thoughts and repetitive compulsions associated with this disease. We discuss classical targets as well as contemporary neuromodulatory approaches that have been shown to provide symptomatic relief. Recently, deep brain stimulation (DBS) of the anterior limb of the internal capsule/ventral striatum received Conformité Européene (CE) mark and Food and Drug Administration (FDA) approvals for treatment of intractable OCD. Remarkably, this is the first such approval for neurosurgical intervention in a strictly psychiatric indication in modern times. This target is discussed in detail along with alternative targets currently being proposed. We close with a discussion of gamma knife capsulotomy, a modality with deep historical roots. Further directions in the surgical treatment of OCD will require better preoperative predictors of postoperative responses, optimal selection of individualized targets, and rigorous reporting of adverse events and standardized outcomes. To meet these challenges, centers must be equipped with a multidisciplinary team and patient-centered approach to ensure adequate screening and follow up of patients with this difficult-to-treat condition.

Applicants for stereotactic neurosurgery for psychiatric disorders: role of the Flemish advisory board

OBJECTIVE

Research on stereotactic neurosurgery for psychiatric disorders (SNPD) is rapidly evolving. Knowledge on patients undergoing SNPD is of crucial importance. We describe applicants for SNPD and examine the necessity for a multidisciplinary advisory board.

METHOD

Summary of the current practice of the Flemish advisory board (SNPD committee) and analysis of a questionnaire investigating the attitude of clinicians on SNPD.

RESULTS

In 7 years, 91 applications were submitted, nine patients did not fulfill diagnostic criteria for OCD, 65 patients received a positive recommendation, 50 SNPD procedures were performed. The prevalence of SNPD in the current year in Belgium is 0.6/million inhabitants. Ninety-seven per cent of clinicians consider the expertise and advice of the SNPD committee essential for indication setting. Forty-four percent of clinicians consider referral of a patient for capsulotomy, 82% for electrical brain stimulation.

CONCLUSION

Neurosurgery is exclusively considered for severe, treatment-refractory psychiatric disorders. Clinicians consider the SNPD committee essential in the decision-making process prior to intervention.

Frameless stereotactic subcaudate tractotomy for intractable obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a chronic, disabling disorder. Psychosurgery may be indicated for a subset of patients for whom no conventional treatment is satisfactory. This paper focuses on the stereotactic subcaudate tractotomy (SST). Thus far, these procedures have been carried out using frame-based stereotactic techniques. However, modern - highly accurate - frameless stereotactic procedures have successfully been introduced in neurosurgical practice. We developed a novel frameless stereotactic subcaudate tractotomy procedure with promising initial results in a patient suffering from intractable OCD. This is the first report on frameless SST. Future studies should examine whether other ablative stereotactic psychosurgery procedures can be done using frameless stereotactic methods.

Paradoxical rate-dependent effect of fluoxetine on captivity-induced stereotypies in bank voles

Treatment of stereotypies in human and animal clinics is still empirical due to our incomplete understanding of underlying mechanisms. As a consequence, experimental studies in controlled laboratory conditions are necessary. Bank voles (Clethrionomys glareolus), housed in barren laboratory cages, often develop stereotyped up-and-down jumping even before the age of 1 month. The aim of this study was to investigate how captivity-induced stereotypies respond to fluoxetine (Prozac), a selective serotonin reuptake inhibitor. During a control period of 10 days saline was administered daily s.c. to 6-month-old bank voles (n=24). In the subsequent 30 days, 16 animals received a dose of 10-mg/kg s.c. daily while 8 other animals were injected a dose of 20-mg/kg fluoxetine. Stereotypies, general activity, food intake and body weight were measured. Dose-related and paradoxical rate-dependent effects were found on stereotypies. After 10 days of treatment, the stereotypy levels of the animals with high pre-drug stereotypy rates decreased in contrast with those of low stereotypers which increased. No effect was found on general activity and food intake. Weekly weighing revealed an increase of weight during the total drug period and a return to pre-drug levels during the week thereafter.

Long-term electrical capsular stimulation in patients with obsessive-compulsive disorder

OBJECTIVE

Because of the irreversibility of lesioning procedures and their possible side effects, we studied the efficacy of replacing bilateral anterior capsulotomy with chronic electrical capsular stimulation in patients with severe, long-standing, treatment-resistant obsessive-compulsive disorder.

METHODS

We stereotactically implanted quadripolar electrodes in both anterior limbs of the internal capsules into six patients with severe obsessive-compulsive disorder. Psychiatrists and psychologists performed a double-blind clinical assessment. A blinded random crossover design was used to assess four of those patients, who underwent continuous stimulation thereafter.

RESULTS

The psychiatrist-rated Yale-Brown Obsessive Compulsive Scale score was lower in the stimulation-on condition (mean, 19.8 +/- 8.0) than in the postoperative stimulator-off condition (mean, 32.3 +/- 3.9), and this stimulation-induced effect was maintained for at least 21 months after surgery. The Clinical Global Severity score decreased from 5 (severe; standard deviation, 0) in the stimulation-off condition to 3.3 (moderate to moderate-severe; standard deviation, 0.96) in the stimulation-on condition. The Clinical Global Improvement scores were unchanged in one patient and much improved in the other three during stimulation. During the stimulation-off period, symptom severity approached baseline levels in the four patients. Bilateral stimulation led to increased signal on functional magnetic resonance imaging studies, especially in the pons. Digital subtraction analysis of preoperative [(18)F]2-fluoro-2-deoxy-d-glucose positron emission tomographic scans and positron emission tomographic scans obtained after 3 months of stimulation showed decreased frontal metabolism during stimulation.

CONCLUSION

These observations indicate that capsular stimulation reduces core symptoms 21 months after surgery in patients with severe, long-standing, treatment-refractory obsessive-compulsive disorder. The stimulation elicited changes in regional brain activity as measured by functional magnetic resonance imaging and positron emission tomography.

Electrical stimulation of the anterior limbs of the internal capsules in patients with severe obsessive-compulsive disorder: anecdotal reports

Anterior capsular stimulation induces some improvement in severe treatment-resistant OCD patients. At this stage, not all stimulation-induced effects can be explained. The effects are a valuable source for further neurophysiologic and neuroanatomic research. It was reassuring that when the group of Drs Rasmussen, Greenberg, and Friehs in Providence and the group of Drs Rezai, Montgomery, and Malone in Cleveland started to operate on OCD patients using exactly the same technique, similar effects were seen in the patients. The authors still want to stress that anterior capsular stimulation remains investigational and needs optimization, especially to try to solve the problem of the short battery life of the stimulators.

Electrical stimulation of the brain for psychiatric disorders

Despite advances in therapies, there remain psychiatric patients who are extremely ill and cannot be helped by classic psychiatric treatments, including psychotherapy and drug therapy. Certain of these patients may be helped by use of bilateral brain lesioning. The complication rate of standard stereotactic psychosurgery techniques is very low. The main rationale for the continued experimental use of deep brain stimulation (DBS) in neurosurgery for mental disorders is its reversibility. This reversibility is not an advantage in terms of the benefits obtained, but rather if side effects emerge. In addition, electrical stimulation may provide patients with some autonomy for their treatment. The first, very preliminary results of electrical stimulation for obsessive-compulsive disorder and for a small heterogeneous group of patients with other psychiatric disorders have been published. Electrical stimulation of the brain for psychiatric disorders may become a new treatment option for certain intractable psychiatric disorders. Nevertheless, the mechanism of action of DBS in psychiatric disorders is unknown, and the experience with this modality is extremely limited. The first results look promising, but this treatment option may prove unusable for some time because of a lack of knowledge of appropriate brain stimulation targets and technical problems such as the availability of sufficient current supply.

Modern neurosurgery for psychiatric disorders

OBJECTIVE

The evolution, rationale, and results of modern functional neurosurgery to treat psychiatric disorders are documented. The potential benefits of neurosurgical treatment for selected, critically ill, psychiatric patients are considered.

METHODS

The history, anatomic features, and evolution of and contemporary indications for the four currently used procedures (cingulotomy, subcaudate tractotomy, limbic leukotomy, and capsulotomy) are reviewed. Available outcome, neuropsychological assessment, and functional imaging data are presented.

RESULTS

Recently, there has been a renaissance of interest in the surgical treatment of psychiatric disease. Modern psychiatric neurosurgical procedures are quite safe, with extremely low surgical mortality rates and transient postoperative morbidity. In selected cases, patients with conditions that had previously been completely refractory to comprehensive medical and behavioral intervention demonstrated significant improvement. This improvement was usually observed in the absence of long-term adverse neuropsychological consequences.

CONCLUSION

Recent outcome studies, together with advances in neurobiology, psychiatry, functional imaging, and stereotaxy, support the further investigation of modern functional neurosurgical procedures to treat psychiatric disorders and their application for a subset of psychiatric patients with conditions refractory to all other therapies.

Electrical stimulation in anterior limbs of internal capsules in patients with obsessive-compulsive disorder

Chronic electrical stimulation instead of bilateral capsulotomy was done in four selected patients with long-standing treatment-resistant obsessive-compulsive disorder. In three of them beneficial effects were observed.

Sixty years of psychosurgery: its present status and its future

After its introduction 60 years ago, psychosurgery witnessed a remarkable rise followed by a decline. In the 1990s, it is a marginal treatment practised by a few psychiatrists in some specialised centres around the world. The psychiatric profession, however, continues to support it, and there is some evidence for a recent renewal of interest in the procedure. In this paper, the reasons for this reluctant acceptance of psychosurgery are examined, and the factors that are likely to determine its future are identified. The profession is urged to keep the interest in psychosurgery alive until further theoretical and empirical developments can either announce its death or lead to a resurgence of psychiatric neurosurgery in its present or modified form.