Outcome after the psychosurgical operation of stereotactic subcaudate tractotomy, 1979-1991

The outcome of all psychosurgical operations (stereotactic subcaudate tractotomies) performed at the Geoffrey Knight National Unit for Affective Disorders in London since 1979 is reviewed. Of patients who had suffered severe mood or obsessive-compulsive disorders before surgery, 84 of 249 (34%) were well 1 year after. The effects of gender, psychiatric diagnosis, and age on outcome are assessed. The findings are compared with a 1975 outcome study, and explanations for apparent differences are proposed.

Psychosurgery: stereotactic subcaudate tractomy. An indispensable treatment

BACKGROUND

Stereotactic subcaudate tractotomy (SST) is the only type of psychosurgery performed at the Geoffrey Knight Unit, London, where nearly 1300 operations have been done since 1961. Statistically reliable data are not available to prove the effectiveness of SST. A detailed statement about contemporary psychosurgery is given.

METHOD

Relevant publications from the Unit and via Medline are discussed. The outcome figures are reviewed. The outcome is assessed at the Unit in global and clinical terms, associated with results of self-completed questionnaires.

RESULTS

SST allows 40-60% of patients to live normal or near-normal lives, perhaps with continuation of medication. A reduction in suicide rate to 1% post-operatively, from 15% in cases of uncontrolled affective disorders is seen.

CONCLUSION

As a treatment of last resort, no controlled trial against a comparable treatment is possible. It appears reasonable to offer SST to patients with suicidal and deluded depression or with frequently swinging moods, not responding to other treatments.

Antemortem measurements of neurotransmission: possible implications for pharmacotherapy of Alzheimer's disease and depression

Aspartic acid, 5-hydroxyindoleacetic acid, glutamic acid, homovanillic acid and 3-methoxy-4-hydroxyphenylethylene glycol was determined in samples of ventricular fluid from 82 subjects. Laminar distribution of the total number (Bmax value) of serotonin 1A receptors was determined on seven neurosurgical samples of neocortex. Apart from an association in a small subgroup of subjects between homovanillate concentration and corticosteroid medication, no complicating influences of treatment preceding operation were found. The content of the serotonin metabolite alone was significantly reduced in intractable depressive illness (bipolar and major depressive disorders) compared with neurological conditions subdivided into Alzheimer's disease, other dementias and other conditions. There was no other significant difference between these groups for the compounds measured. The total number of serotonin 1A receptors was highest in the superficial layers, being considerably higher than in the rat, irrespective of cortical layer. This part of the study indicated that these receptors are important for regulating activity of human corticocortical glutamatergic neurons. The results are discussed in relation to treating depression with serotonergic agents and targeting corticocortical glutamatergic neurons as well as acetylcholine in Alzheimer's disease.

Effect of psychotropic drugs on excitatory amino acids in patients undergoing psychosurgery for depression

Samples of ventricular CSF were taken from 52 consecutive patients admitted for psychosurgery for intractable depression. Concentrations of asparagine, aspartate, glutamine, glutamic acid, and serine were determined. Glutamate and aspartate concentrations, implicated in excitotoxic brain damage, were not affected by various types of psychotropic drug treatment. Serine, a modulator of glutamate responses, was significantly elevated in samples from subjects receiving antidepressants. These subjects responded poorly to the operation. Psychotropic drugs are unlikely to be neurotoxic. Nevertheless, antidepressants may influence excitatory neurotransmission.

Neuropsychological correlates of stereotactic subcaudate tractotomy. A prospective study

Stereotactic subcaudate tractotomy is a surgical procedure performed for the alleviation of intractable affective disorders. It involves the destruction of bifrontal pathways located beneath and in front of the head of the caudate nucleus. We report the first prospective study of the neuropsychological correlates of this operation in 23 patients. Tests of general intelligence, speed and attention, as well as a wide range of focal cognitive tests, including tasks which have been reported in the literature to be sensitive to frontal lobe dysfunction, were administered 1 wk before the operation, 2 wks after the operation and approximately 6 mths after the operation. The results indicated that this operation does not cause any significant, long-term adverse, cognitive deficits. In the post-operative assessment, however, patients show a significant deterioration in their performance on recognition memory tests and a large proportion of them present with a marked tendency to confabulate on recall tasks. In addition, their performance on some of the tasks which are considered to be sensitive to frontal lobe dysfunction is found to be significantly impaired. These deficits are interpreted to reflect frontal lobe dysfunction due to widespread post-operative oedema rather than damage to the subcaudate pathways. The potential for research on these transient effects of the operation for the advancement of our understanding of frontal lobe functions is discussed.

Brain amino acid concentrations and Ca2+-dependent release in intractable depression assessed antemortem

The concentrations of 3 putative neurotransmitters (glutamate, aspartate and gamma-aminobutyrate), 4 related amino acids and 5 non-transmitter-related amino acids have been measured in neurosurgical samples (frontal cortex) from patients with intractable depression and controls. In addition, the glutamate receptor agonist 2-amino-4-sulpho-butanoic acid (homocysteic acid) has been identified in human brain and measured in these samples. There were no changes in the concentrations of amino acids in depressed patients compared to control with the exception of aspartic and homocysteic acids which were elevated in a sub-group of patients with depression compared to control. The Ca2+-dependent release (K+-stimulated) of putative neurotransmitters has been demonstrated for the first time from brain tissue of depressed patients. Glutamate release was unaltered from the control value. Aspartate values showed unexplained variability but it's release and that of gamma-aminobutyrate were elevated in some depressed subjects. These results do not support the hypothesis of reduced amino acid function in depressive illness.

Resistant bipolar affective disorder treated by stereotactic subcaudate tractotomy

The results of stereotactic subcaudate tractotomy in nine patients with resistant bipolar affective disorder are presented in the form of a single case study with a summary of the other eight cases. Follow-up studies at 2-4 years showed substantial improvement in five patients and amelioration of symptoms in a further four patients, with a tendency for a greater improvement in the manic than in the depressive episodes. These preliminary results suggest that there is a place for this operation in the management of severe bipolar affective disorders which are not responding to any other treatment, although decisive recovery occurs less often than with unipolar depression.

Amino acid levels in depression: a preliminary investigation

Plasma, cerebrospinal fluid and brain tissue amino acid levels were measured in 14 patients with affective illness and generally confirm previous findings. There was no correlation between these values and age, sex, family history and levels of anxiety. GABA levels measured in cortex tissue were negatively correlated with depressive mood (P less than 0.05), supporting a possible involvement of GABA in depressive illness.

Psychosurgery in Britain now

Between 1979 and 1986 the number of psychosurgical operations carried out in Britain fell from 70 to 15 procedures annually. There are a number of possible reasons for this change of which increased experience with new regimes of psychotropic medication is perhaps the most important. The new Mental Health Act (1983) which brought psychosurgery under the direct jurisdiction of the law was followed by a sudden reduction in the number of patients treated but referals are now increasing. In current psychiatric practice, classification relies largely on description of syndromes, each characterised by a set of core symptoms. Schizophrenia and affective psychoses (endogenous depression, mania and obsessional illness of late onset) are characterised by disturbances of mood, thinking and perception often so profound as to impair the patient's contact with reality. In contrast, neuroses produce symptoms which are quantitatively, rather than qualitatively different from normal experience and psychosurgery has no place in their treatment. Following the introduction of phenothiazines in the early 1950's schizophrenia ceased to be an indication for psychosurgery. For a small group of severely disabled and distressed people suffering from endogenous depressive and obsessional illnesses, when other treatments have failed or ceased to be effective, psychosurgery remains an appropriate treatment. Just over half the patients treated at the Geoffrey Knight Unit are relieved to the extent that they are either free of symptoms or such symptoms that remain do not significantly impair social function. Following operation recovery is slow and progressive and a programme of rehabilitation is usually necessary. Personality which is often severely damaged by the effects of long illness returns towards normal. Neuropsychiatric evaluation has consistently failed to demonstrate adverse cognitive effects. Evaluation and selection of patients for operation should be done by a psychiatrist and neurosurgeon working in partnership. Stereotactic techniques have made it possible to produce precisely located lesions of consistent size, virtually eliminating side effects and reducing the epileptic risk to between two and three percent. The Mental Health Act, contrary to early expectations, has allowed that psychosurgery retains a place in the treatment of a small highly selected group of patients.

The stalemate position

The psychosurgical operation of stereotactic subcaudate tractotomy can be a highly effective treatment for chronic and intractable affective disorders. We have lately given increasing attention to cases where the depressed mood appears to lift although there is little improvement in social function. In these cases there has been a failure of rehabilitation and the complexities of this process post-operatively are discussed. In addition, relatives report in some 10% of cases "personality changes" after the operation which are not perceived in this way by an independent medical assessor and these observations seem to depend upon relatives mis-interpreting the resumption of pre-morbid personality function after long illnesses as undesirable side-effects. Case histories illustrating the problems are described. Treatment and rehabilitation strategies are outlined.

Ventricular size and CSF transmitter metabolite concentrations in severe endogenous depression

The relationship between neurotransmitter metabolite concentrations and measurements of ventricular size on CAT scans and pneumoencephalographs was investigated in 15 patients with severe affective disorder. An association was identified between reduced levels of plasma free tryptophan and ventricular enlargement, and also between raised ventricular CSF levels of 5 HIAA and ventricular enlargement.

Ventricular size, the dexamethasone suppression test and outcome of severe endogenous depression following psychosurgery

To assess the possible significance of cerebral ventricular size and the dexamethasone suppression test (DST) in the outcome of severe endogenous depression, 28 patients were followed up and reviewed 1 year after stereotactic subcaudate tractotomy. Neither ventricular size nor the dexamethasone suppression test predicted either a good or poor outcome. There was no relationship between ventricular size and the DST results.

Psychological aspects of patients having multiple operations for low back pain

The aim of this study was to investigate whether psychological abnormalities were present in patients still complaining of low back pain after more than one operation. It was found that these patients were more psychiatrically disturbed and socially disabled than a matched control group whose back pain responded to one operation. These results suggest that patients requiring assessment for a possible second laminectomy should also be psychiatrically examined.

A neuroendocrine study of stereotactic sub-caudate tractotomy

The growth hormone and hypotensive responses to clonidine have been measured in six drug free severely depressed patients before, and at two weeks after, the surgical procedure of stereotactic sub-caudate tractotomy. The responses were unaltered two weeks after operation, by which time a small clinical improvement was evident. These findings are discussed in relation to central alpha adrenoceptor functions in depression, and the effect upon this of antidepressant treatment.

Collagen deficiency and ruptured cerebral aneurysms. A clinical and biochemical study

Skin and temporal arterial biopsies were obtained from 17 patients undergoing surgery for ruptured cerebral aneurysm, and specimens were taken from six age- and sex-matched control surgical patients. Radioactively labeled and control tissue collagen patterns were studied by interrupted polyacrylamide gel electrophoresis (PAGE), using the trisborate buffer system or by carboxymethyl cellulose (CMC) chromatography. Type III/I collagen ratios were then measured from autoradiographs of the radioactively labeled samples using the Joyce Loebl gel scanner adapted for flat bed gels. In the case of the CMC labeled material, the ratios were measured by the ratios of the summed radioactively labeled alpha 1(III), alpha 2(II), and alpha 2(I) peaks. Eleven of the 17 patients were Type III collagen-deficient while all of the six control patients had normal collagen ratios. The implications of these findings are discussed.

Pneumo-encephalographic and computerized axial tomography scan changes in affective disorder

The pneumo-encephalographs and computerized axial tomography scans of fifty patients with severe affective disorder were studied. Measures of ventricular size were compared with those reported by other workers. Findings suggested that some patients suffering from severe affective illness showed abnormalities of brain structure as demonstrated by ventricular enlargement.

Indolic substances in plasma, cerebrospinal fluid, and frontal cortex of human subjects infused with saline or tryptophan

Psychiatric patients undergoing the psychosurgical operation of stereotactic subcaudate tractotomy were infused intravenously with either saline or L-tryptophan (15 mg/kg/h). Plasma, lumbar cerebrospinal fluid (CSF), ventricular CSF and a specimen of frontal cortex were collected. The relationships of plasma concentrations of substances claimed to influence brain tryptophan concentration (total tryptophan, free tryptophan, large neutral amino acids) with the concentration of tryptophan in the cortex and CSF were investigated. Tryptophan infusion resulted in plasma tryptophan values comparable to those found after oral doses used in treating depression or insomnia, and about sixfold increases of tryptophan in the cerebral cortex. Increased brain 5-hydroxytryptamine synthesis was indicated by significant rises of CSF 5-hydroxyindoleacetic acid. The concentration of plasma free tryptophan was a better predictor than plasma total tryptophan of cortex tryptophan concentration. As all correlation coefficients of plasma versus brain or plasma versus ventricular CSF tryptophan concentrations were decreased when allowance was made for differences of concentration of large neutral amino acids, the results suggest that the role of these substances within their physiological range as inhibitors of tryptophan transport to the brain may previously have been overemphasised.

Electroencephalographic changes as prognostic indicators after psychosurgery

Thirty-five patients were studied by EEG with recordings taken the day before, two weeks after, and six months after psychosurgery. Most showed a characteristic frontal slow activity of varying degrees after operation with varying enhancement of background activity. The amount and spread of the frontal slow waves two weeks after operation showed a significant positive correlation with the clinical outcome one year later, which suggests a relatively objective and very early indication of the subsequent clinical response to psychosurgery.

Corrigenda for Luxotonic responses of units in macaque striate cortex

Page 1504: Yukihiko Kayama, Donald R. Riso, John R. Bartlett, and Robert W. Doty, “Luxotonic responses of units in macaque striate cortex.” The sentences beginning on the second line, left-hand column should read: “In either case the usual response was a large change, either enhancement or suppression, which followed immediately on the change in illumination. Commonly, the rate of discharge then gradually…” Page 1509: the last sentence of the legend to Fig. 14 should read, “Unit encountered 2 mm beneath dura mater in right operculum about 15 mm from midline, i.e., in striate cortex receiving projection from about 3° from center of visual field.”

Rarity of luxotonic responses in cortical visual areas of the cat

Neuronal responses to continuous, diffuse white light or darkness were studied in cortical visual areas 17, 18, 19 and Clare-Bishop of the unanesthetized cat. In contrast to squirrel monkeys and macaques in which about 40 or 25% of the units in striate cortex are luxotonic (response to continuous light or darkness sustained > 2.0 min), all of the visual areas in the cat had fewer than 4.0% of the units exhibiting such luxotonic activity. The functional basis of this difference may be related to differences between the two species in the quantitative balance of antagonistic receptive field properties.

Failure to find luxotonic responses for single units in visual cortex of the rabbit

The firing frequency of a population of 213 units in striate and circumstriate cortex of the moderately restrained rabbit was studied under the influences of alternating 1-min periods of darkness versus steady, diffuse, featureless illumination. The intent was to determine whether luxotonic responses, so prominent in striate cortex of primates, are indeed absent in rabbits. Such was the case, there being only transient occurrences in three units where the continuing rate of discharge in darkness was double that in the light. There were, however, much more modest differences in rate of continuing discharge in light versus darkness, and for 46% of the units discharging greater than 1/s this difference exceeded 10% and/or 1/s. The rate of discharge in any case did not provide a reliable index as to the characteristics of a unit's receptive field in response to patterned visual stimuli. The nature and function of luxotonic activity in primates still not being understood, it cannot be decided whether its absence in rabbits represents a true qualitative or merely a quantitative difference between species.

Luxotonic responses of units in macaque striate cortex

1. Single units in striate cortex were studied in alert macaques while they viewed a ganzfeld. Of the 385 well-isolated units studied for 10 min to 2 h, 24% gave "luxotonic" responses, i.e., their rate of discharge for 1 min or more in diffuse, featureless, wideangle illumination (20-450 cd/m2) was at least double that during a comparable period in darkness, or vice versa, and not attributable to eye movements of blinking. Those discharging faster in the light, "photergic" units, outnumber those responding to darkness, "scotergic" units 1 by 4:1. 2. In the lateral geniculate nucleus, on the other hand, among 46 units studied, 28% were luxotonic, but scotergic units were the more common. Both types were present in both magno- and parvocellular laminae. 3. For striate cortex two-thirds of the luxotonic units were binocular. Some showed highly similar response for either eye alone, and essentially no summation binocularly; others had grossly differing responses from each eye, and complex binocular interaction. 4. Many units of all types at striate cortex showed significant modulation of their activity consequent to saccadic eye movements made in darkness, whereas comparable modulation was not observed at the lateral geniculate nucleus. 5. On the basis of these and other findings it is concluded that luxotonic cortical activity is prominent probably only in alert primates, and that this is a consequence of the fact that all retinal ganglion cells in primates synapse in the lateral geniculate nucleus (Ref. 9). Possible functions range from mere trophic input to providing a veridical image or a scaling factor for maintenance of perceptual constancy in the face of varying levels of general illumination.

The role of computerized tomography in the care of the injured

The records of 377 patients with head injuries admitted to the South East Thames Regional Neurosurgical Unit in the two years following the introduction of the EMI scanner (computerized tomography) were examined. Each patient was assessed on the reason for transfer, the necessity for transfer, the safety of transfer and whether immediate access to a scanner would have altered management. The results show that the majority of patients were referred because of a possible intracranial haematoma. Thirty per cent of the patients required operation, in 6 per cent transfer was unnecessary and 10 per cent arrived with inadequate resuscitation. It is suggested that with a wider deployment of head-dedicated scanners to some accident centres, the number of patients with head injuries at present being transferred to special units for assessment would be reduced substantially, with improvement of patient care.

Size of cerebral ventricles in 66 psychiatric patients

The routine air ventriculograms of 66 psychiatric patients, aged from 22 to 73 years, taken during the psychosurgical operation of stereotactic subcaudate tractotomy, were studied. Ventricular size was unrelated to progressive ageing, but a minority of patients over 60 years had abnormally large ventricles, not invariably associated with cognitive impairment on testing. Enlargement was associated with a clinical diagnosis of schizoaffective illness but not with past ECT.

Evaluating cost-effectiveness of diagnostic equipment: the brain scanner case

An approach to evaluating the cost-effectiveness of high-technology diagnostic equipment has been devised, using the introduction of computerised axial tomography (CAT) as a model. With the advent of CAT scanning, angiography and air encephalography have a reduced, though important, role in investigating intracranial disease, and the efficient use of conventional equipment requires the centralisation of neuroradiological services, which would result in major cash savings. In contrast, the pattern of demand for CAT scanning, in addition to the acknowledged clinical efficiency of the scanner and its unique role in the head-injured patient, ephasies the need for improved access to scanners. In the interest of the patients the pattern of service must change.

A clinical study of the EMI scanner: implications for provision of neuroradiological services

The records of the first 571 patients to be examined with an EMI brain scanner were assessed. The patients were divided into diagnostic categories according to their clinical presentation. The intracranial investigations that would have been performed had the scanner not been available were compared with the investigations that were actually performed. As expected, the number of contrast investigations fell, but the reduction surpassed expectation. If the full clinical impact of the scanner is to be realised the patient's illness must be defined in detail and strict attention paid to radiographic detail. By reducing the number of special contrast investigations use of the scanner enables existing contrast facilities to serve a wider population; and use of the brain scanner in district general hospitals would improve the service to patients, especially those with head injuries.

Studies of endocrine activity, plasma tryptophan and catecholamine excretion on psychosurgical patients

The Geoffrey Knight Psychosurgical Unit admits patients on a regular basis and thus offers special opportunities for studying severely ill psychiatric cases, all having one particular treatment under relatively controlled conditions. The opportunity has been taken to repeat various metabolic studies previously reported to be abnormal in some psychiatric illnesses. In the present investigation several measures of endocrinological activity were studied, as was plasma tryptophan, both free and bound. None of these data confirmed reports of abnormalities and neither did the values found at operation help to predict clinical outcome 1 year later, which was another possibility. Urinary catecholamines were also measured and 2 weeks after operation. Male patients, regardless of diagnosis, showed a mean increase in adrenaline output after operation compared with the pre-operative value and this was significantly different from the females, who showed a small mean decrease. The depressed patients showed a significant reduction in noradrenaline excretion after operation compared with before operation and this trend was enhanced in those of good outcome at 1 year, the difference from those who responded poorly being significant. It could be that the ventromedial lesion that is produced alters noradrenaline metabolism or autonomic activity in depression and this possibility merits further study.

Deleterious effects of prolonged electrical excitation of striate cortex in macaques

Macaques were trained to respond to electrical excitation applied through electrodes permanently implanted within or upon striate cortex. Threshold current for the animal to detect this stimulation was highly consistent from day to day and, in the absence of tissue encapsulation of the electrodes or deliberately inflicted damage, remained stable indefinitely, 38 months in the longest case so far. Stimulating continuously for 1-8h, however, produces an elevation of threshold, which may be permanent or temporary, depending upon a variety of conditions. A major cause of such injury is the hydrolysis commonly occurring consequent to passage of low-level currents between solutions and metal electrodes. Even when the hydrolytic reaction is eliminated by restricting the level of electrode polarization or by using capacitative stimulation with tantalum pentoxide electrodes, a rise in threshold often still occurs with protracted stimulation. With proper control in some instances, however, effective stimulation at 2-10 times the threshold level could be maintained indefinitely without apparent injury, e.g. in a blind monkey having a threshold of 290 muA that could respond immediately to an 80-muA diminution in 580-muA, 0.2-msec stimulus pulses which had been applied steadily for 1 h at 50 Hz.

Precursors and metabolites of 5-hydroxytryptamine and dopamine in the ventricular cerebrospinal fluid of psychiatric patients

Tryptophan and 5-hydroxyindoleacetic acid (precursor and metabolite respectively of 5-hydroxytryptamine) were determined in ventricular CSF of psychiatric patients undergoing stereotactic subcaudate tractotomy. Tyrosine and homovanillic acid (precursor and metabolite respectively of dopamine) were also determined. Results suggest an association between affective state and the above precursor amino acids with lower concentrations in primary depression and higher ones when anxiety or agitation predominate. This leads to lower 5-hydroxyindoleacetic acid concentrations in depression and higher concentrations in anxiety and agitation.

Influence of saccadic eye movements on geniculostriate excitability in normal monkeys

Using permanently implanted electrodes in squirrel monkeys and macaques, transmission through the lateral geniculate nucleus (LGN) was assayed from the amplitude of potentials evoked in optic radiation by and electrical pulse applied to optic tract. Averaging of either individually or machine selected potentials, elicited at 0.3, 1.0, 20 or 50 HZ, in all cases showed a decrease in transmission ranging from 5-60% in the period after saccadic eye movements made ad libitum. The suppression was greater in a patterned visual environment than in diffuse illumination, which in turn was greater than that occurring following saccades in the dark. Demonstration of the effect in darkness always required data averaging and never exceeded 20%. The effect was consistently greater in the magnocellular than parvocellular component. Suppresion was often abruptly terminated and replaced by a facilitation of 5-15% about 100 msec after saccade detection. Comparable effects were observed for excitability of striate cortex tested by a stimulus pulse applied to optic radiation. In addition, sharply demarcated potentials inherently arising in LGN and striate cortex were found in association with saccades made even in total darkness. Neglecting a possible but dubious contribution from eye muscle proprioceptors, the experiments establish the existence of a centrally originating modulation of visual processing at both LGN and striate cortex in ralation to saccadic eye movement in primates. This modulation may partially underlie the phenomenon of "saccadic suppression" and hasten the acquistion of a meaningful visualsample immediately following an ocular saccade. It remains uncertain as to how it may relate to similar or greater effects accompanying changes in alertness, or to fluctuations of unknown origin occurring sometimes semirhythmically at 0.05-0.03 HZ (Fig 7).