Neurosurgery for mental disorder (NMD) is a procedure performed on the frontal lobes of the brain, which are behind the forehead. This area also contains the limbic system, which is concerned with emotional responses such as rage, fear and joy, and physical responses to the environment that are not under conscious control, such as changes in heart rate and blood pressure.
NMD may be used to treat severe, incapacitating non-schizophrenic mood disorders, but only when all other treatments have failed. It is not used to alter behaviour.
Nowadays, NMD is most commonly used to treat severe depression and obsessive compulsive disorder (OCD). However, in cases where a patient has never responded to medication or electroconvulsive therapy (ECT), it is possible that all physical treatments, including surgery, are inappropriate.
NMD does not cure severe, incapacitating mood disorders, and people who undergo NMD are likely to need continued psychiatric support after the procedure, even if it is considered a success. [1]
Psychiatric conditions that are not helped include personality disorders, uncomplicated schizophrenia, and anorexia nervosa. [2]
The procedure cannot be reversed. NMD is not performed on people under 20 years of age.
The aim of the procedure is to disrupt connections in the nerve circuits in very small areas within the limbic system that seem to be creating or contributing to persistent depressive or obsessive thinking. [3] This is done using a minimally invasive procedure called stereotactic surgery, which uses three-dimensional coordinates to locate a particular target. It is carried out under general anaesthesia.
A specially constructed apparatus called a stereotactic frame is attached to the patient's skull through small incisions in the scalp. Where possible, incisions are made in skin folds. The hair is shaved only in these small areas.
The frame holds probes that are inserted into the brain through small holes in the skull (called burr holes), which are created using a special drill. Dedicated computer software is used in conjunction with imaging such as computerised tomography (CT) or magnetic resonance imaging (MRI) to guide the probe(s) precisely to the desired target within the brain (to an accuracy of one millimetre). Most modern procedures then use an electrical current to generate heat to destroy a very small area of tissue at the end of the probe (this is known as radiofrequency ablation). The incisions in the scalp are stitched and/or glued after removal of the stereotactic apparatus.
There is no international consensus on the best target site for the procedure, and different techniques are used at different treatment centres. The following operations (described in more detail below) are used in the UK:
NMD usually takes about one and a half hours, most of which is taken up by scans to monitor the position of the probe.
Patients sit out of bed on the second day and are mobile on the third day after the operation. Rehabilitation must be gradual because recovery is a slow process.
This procedure targets an area of the brain called the caudate nucleus. Two probes are inserted via burr holes created in the frontal bone above the air sinuses (i.e. in the forehead) and guided to the caudate nucleus. The target area is then destroyed using radiofrequency ablation. [4]
In bilateral anterior capsulotomy, two probes are passed via incisions on each side of the midline on top of the head into the part of the brain called the internal capsule, which is close to the caudate nucleus. A small electric current is then passed via the probes to destroy a small area of brain tissue. [5]
Bilateral anterior cingulotomy involves a similar technique to bilateral capsulotomy but targets an area of the brain called the anterior cingulate gyrus.
Some of the side effects that can occur may be associated with any brain operation, and some are specific to NMD.
The risks associated with brain surgery are damage to the blood vessels (which may result in stroke, although this is very rare in NMD), confusional states, and epilepsy. Immediately after the operation, fluid in the tissues may cause pressure in the front of the brain (post-operative frontal oedema), leading to confusion, which may last up to a month.
Adverse effects associated specifically with NMD include headaches, which may be severe and last for some days, and, in the long term, weight gain and apathy. Weight gain is associated with capsulotomy and subcaudate tractotomy, but not with cingulotomy; the reason for this is not known. Personality changes following NMD have been reported in some people, but are considered rare.
There is no evidence that NMD causes intellectual impairment, and in some cases, IQ scores have been raised, probably because of the relief of symptoms that had previously impaired concentration. [6]
NMD is performed in only a small number of patients each year. During 2007–09, multidisciplinary teams appointed by the Mental Health Act Commission authorised two operations. Both patients underwent bilateral stereotactic anterior capsulotomy at the University Hospital of Wales. There were no other cases that were refused. [7]
The number of procedures performed in previous reporting periods are shown in the table below. [8]
|
Reporting period |
Number of referrals |
Number who received treatment |
|
1997–1999 |
17 |
17 |
|
1999–2001 |
9 |
9 |
|
2001–2003 |
13 |
6 |
|
2003–2005 |
7 |
6 |
|
2005–2007 |
7 |
5 |
It is important to remember that NMD is used only when all other treatments have failed, so patients have severe, hard-to-treat illness. It is difficult to measure the success rates of a procedure that is done so rarely. Both patients who underwent the procedure in Wales in 2007–2009 showed positive results, and reported that their lives had improved as a result. [9]
Research published in the USA suggests that fewer than half of those treated for severe depression show a significant improvement (50 per cent or greater reduction in symptoms of depression). [10] In Dundee, 15 of 25 patients (60 per cent) showed improvement in symptoms of depression after cingulotomy, and remission was achieved in five patients (20 per cent) (the author did not report whether remission was complete or how long it lasted). [11]
A paper reporting the results of subcaudate tractotomy for depression suggests that people who were no longer depressed after the intervention showed an indifference to negative events that is not seen in people who are successfully treated for depression in usual ways. [12]
NMD is carried out in centres in the University Hospital of Wales, Cardiff, and Ninewells Hospital, Dundee. Dundee uses cingulotomy for resistant depressive disorder, and capsulotomy or cingulotomy for intractable OCD. [13]
There is no centre for NMD in England.
A local psychiatrist refers the patient to the psychosurgical team (not just to the neurosurgeon). Good practice guidelines state that the full hospital notes are needed for assessment, and a close relative should accompany the patient and be interviewed as well.
In England and Wales, under the Mental Health Act 1983, NMD cannot be performed without the patient’s consent. In Scotland, the Mental Health (Care and Treatment) (Scotland) Act 2003, allows NMD to be performed without consent in cases where a patient is not capable of giving consent and does not object, and the Court of Session has made an order declaring that the treatment may be lawfully given.
The United Nations resolution on The protection of persons with mental illness and the improvement of mental health care (A/RES/46/119), [14] passed on 17 December 1991, includes the following statement:
“14. Psychosurgery and other intrusive and irreversible treatments for mental illness shall never be carried out on a patient who is an involuntary patient in a mental health facility and, to the extent that domestic law permits them to be carried out, they may be carried out on any other patient only where the patient has given informed consent and an independent external body has satisfied itself that there is genuine informed consent and that the treatment best serves the health needs of the patient.”
The Code of Practice for Wales (published in 2008) refers to the Mental Health Act Commission (MHAC), which was replaced in 2009 by the Care Quality Commission in England and by the Healthcare Inspectorate in Wales.
NMD is covered by section 57 of the Mental Health Act 1983, which covers all patients, whether voluntary or detained under another section of the Act. Under section 57, psychosurgery and treatments specified in Department of Health regulations as giving rise to special concern can be given only if all three of the following requirements are met:
The Mental Capacity Act may not be used to give treatment to anyone to whom section 57 applies.
The following is taken from the Mental Health Act 1983 Code of Practice for Wales, relating to treatments requiring consent and a second opinion: “A decision to provide treatments under section 57 requires careful consideration, given their significance, sensitivity and possible long-term effects. Hospitals proposing to offer such treatments are strongly encouraged to agree with the MHAC the procedures which will be followed to implement the requirements of section 57.17.21. Before referring an individual case to MHAC for a second opinion, the referring professionals should:
Procedures performed in Scotland come under the provisions of the Mental Health (Care and Treatment) (Scotland) Act 2003, which came into effect in October 2005. They are overseen by the Mental Welfare Commission for Scotland, which provides independent clinical assessments for all patients. NMD can be carried out only after a designated medical practitioner, appointed by the Mental Welfare Commission, has given an independent opinion that it will be beneficial to the patient. Two lay people appointed by the Commission must then certify whether or not the patient is capable of consenting; if the person is capable, that he or she consents; and, if not, that he or she does not object to the treatment. Where the person is incapable of giving consent, the Court of Session must make an order declaring that the treatment may be lawfully given before it can proceed. [16]
More information on consent to treatment (for England and Wales only) can be found in Mind’s booklet Mind right’s guide 3: Consent to treatment.
Professor Sam Eljamel, a neurosurgeon who practises NMD in Dundee, has suggested vagus nerve stimulation (VNS) and deep brain stimulation (DBS) as alternatives to NMD, neither of which involves damage to brain tissue.
VNS has been used successfully to treat epilepsy as well as severe depression. [17] A device similar to a pacemaker is implanted in the chest wall, with electrodes connected to the vagus nerve in the neck area. The device sends timed pulses to the vagus nerve. The vagus nerve has branches from many organs of the body to the brain. It is not known why targeting the vagus nerve is helpful in relieving depression and epilepsy.
The people who have received this treatment for depression have tended to be less severely depressed than those undergoing NMD, and the response rate appears to be less good, although it is better than standard treatment for this group of patients. There are also fewer adverse effects. [18]
In this operation, electrodes are implanted using a stereotactic frame, as in standard NMD, but they are left in place and used to stimulate a small area of the brain, rather than destroying the cells. The target cells are the same as in capsulotomy.
A short paper from Sweden published in The Lancet in October 1999 [19] reported the results of this procedure in four patients with long-standing treatment-resistant OCD. Beneficial effects were seen in three of the four patients. In one patient, anxiety and obsessional thinking were relieved when the stimulation was on, but returned when it was turned off. During two weeks’ continuous stimulation, compulsive behaviour and rituals were reduced by 90 per cent. The paper concluded that long-term DBS may be useful in the management of severe OCD.
A review of DBS in the treatment of depression reported that response rates compared favourably with those for NMD; however, DBS is more expensive, partly because of ongoing maintenance and programming.
Side-effects include infection, and complications may also arise from failure of the hardware. In addition, the implants mean that ECT cannot be used. However, the technique is likely to improve, and DBS may eventually replace NMD. [20]
In its thirteenth biennial report, the MHAC expressed concern that DBS is currently unregulated in England and Wales, and could therefore theoretically be given to someone who has not given consent or who lacks capacity. This is not the case in Scotland, where DBS is covered by the same rules as NMD. [21]
Making sense of electroconvulsive therapy (ECT)
Mind rights guide 3: Consent to treatment
Understanding depression
Understanding obsessive–compulsive disorder
Briefing 1: Overview and key provisions of the Mental Capacity Act 2005
Briefing 3: Structures and safeguards under the Mental Capacity Act 2005
Matthews K and Eljamel MS, 2001, ‘Neurosurgery for mental disorder in Dundee’, Dundee NMD Service. Bridges PK, Bartlett JR, Hale AS, et al., 1994, ‘Psychosurgery: stereotactic subcaudate tractotomy, an indispensable treatment’, British Journal of Psychiatry, vol. 165, pp. 599–611. National Health Service for Scotland Working Group on Mental Illness, July 1996, ‘Neurosurgery for Mental Disorder’, The Scottish Office. Bridges PK, Bartlett JR, Hale AS, et al., 1994, ‘Psychosurgery: stereotactic subcaudate tractotomy, an indispensable treatment’, British Journal of Psychiatry, vol. 165, pp. 599–611. Eljamel MS, 2008, ‘Ablative neurosurgery for mental disorders: is there still a role in the 21st century? A personal perspective’, Neurosurgical Focus, accessed from www.medscape.com, 10 May 2010.
Matthews K and Eljamel MS, 2001, ‘Neurosurgery for mental disorder in Dundee’, Dundee NMD Service. The Mental Health Act Commission Thirteenth Biennial Report 2007–2009. The Mental Health Act Commission Twelfth Biennial Report 2005–2007. The Mental Health Act Commission Thirteenth Biennial Report 2007–2009. Cited by Eljamel MS, 2008, ‘Ablative neurosurgery for mental disorders: is there still a role in the 21st century? A personal perspective’, Neurosurgical Focus, accessed from www.medscape.com, 10 May 2010. Eljamel MS, 2008, ‘Ablative neurosurgery for mental disorders: is there still a role in the 21st century? A personal perspective’, Neurosurgical Focus, accessed from www.medscape.com, 10 May 2010. Dalgleish T, Yiend J, Bramham J, et al., 2004, ‘Neuropsychological processing associated with recovery from depression after stereotactic subcaudate tractotomy’, American Journal of Psychiatry vol. 161, pp 1913–1916.
Matthews K and Eljamel MS, 2003, ‘Status of neurosurgery for mental disorder in Scotland’, British Journal of Psychiatry, vol. 182, pp. 404–411.
United Nations. ‘The protection of persons with mental illness and the improvement of mental health care.’ www.un.org/documents/ga/res/46/a46r119.htm Accessed 12 May 2010. Mental Health Act 1983 Code of Practice for Wales, Welsh Assembly Government, 2008. NHS Education for Scotland, Mental Health (Care and Treatment) (Scotland) Act 2003, www.nes.scot.nhs.uk/mha/safeguards1f.htm Corcoran CD, Thomas P, Phillips J, O’Keane V, 2006, ‘Vagus nerve stimulation in chronic treatment-resistant depression’, British Journal of Psychiatry, vol. 189, pp 282–283. Eljamel MS, 2008, ‘Ablative neurosurgery for mental disorders: is there still a role in the 21st century? A personal perspective’, Neurosurgical Focus, accessed from www.medscape.com, 10 May 2010. Nuttin B, Cosyns P, Demeulemeester H et al., 1999, ‘Electrical stimulation in anterior limbs of internal capsules in patients with obsessive-compulsive disorder’, Lancet, vol. 354, pp. 1526.
Eljamel MS, 2008, ‘Ablative neurosurgery for mental disorders: is there still a role in the 21st century? A personal perspective’, Neurosurgical Focus, accessed from www.medscape.com, 10 May 2010.
The Mental Health Act Commission Thirteenth Biennial Report 2007–2009.
This factsheet was written by Katherine Darton, Mind Information Officer, and revised by the author in June 2010.