THE SURGERY OF BRAIN DAMAGE*

’n Oorsig van chirurge in breinskade word gegee. Voorkomende en palliatiewe chirurgie word kortliks bespreek. Chirurgie in spastisiteit sluit in neurektomie, risotome en longitudinale mielotomie en die voor- en nadele word bespreek. Serebellere dentatotomie en ander chirurgie vir abnormale bewegings dateer van 1890 en word nog vandag bebruik. Chirurgie in die basale ganglia area word in uitsonderlike' gevalle aangedui. Ten laaste word chirurgie vir epilepsie en verhoogde intrakraniale druk bespreek.

In the central nervous system, there is no regenera tion of neurones which have been irreversibly damaged so that their function has to be taken over, if at all possible, by other neurones. Such functional take-over m ay be im possible where highly specialised cells, such as those concerned with vision, have been lost. W hat little evidence there is of axonal sprouting after in jury, does not as yet apply to m an and the effects may be as much deleterious as beneficial.
It therefore stands to reason th at prevention must be our forem ost concern at all times, as many forms of brain damage are alm ost entirely preventable, for example birth injury and head injuries resulting from road crashes.

PREVENTIVE SURGERY
All space demanding lesions such as intracranial haem atom as, abscesses, cysts and tum ours, lead to brain damage by virtue of pressure and should therefore be treated prom ptly. Prolonged raised intracranial pressure m ay cause secondary shifts of the brain producing com pression of the brain stem o r vascular occlusion w ith resultant infarction which can be prevented by early rem oval of the causative lesion. T his is the underlying basis of the neurosurgeon's sense of urgency in dealing w ith these problems. H e is only too painfully aware of the disastrous effects of delay.
T ransient neurological episodes suggestive of carotid or vertebral flow im pairm ent should lead to full in vestigations to exclude the presence o f a treatable lesion, such as a carotid artery stenosis or subclavian steal syndrome. Once a patient has transient ischaemic attacks, there is a risk of over 50% o f a completed stroke developing w ithin 18 months. Surgery for re m oval of the source of emboli and relief o f a m echani cal stenosis w ith restoration of adequate cerebral bloodflow, is reasonably simple and safe.
Sim ilarly, the treatm ent of intracranial aneurysms and arteriovenous m a'fn rm atin rs H r^t a ;n ''f1 r" 'u re of the damage already done, b u t to prevent rebleeding and further damage which m ay be fatal.
Every person involved in the managem ent of un conscious patients, should at all times be concerned w ith the patient's respiratory function so that adequate oxygenation of the blood reaching the brain is en sured. Cerebral hypoxia is probably the most frequent yet, m ost easily preventable cause o f brain damage.
* H elen and M orris M a'ierbcreer Professor of N euro surgery, U niversity of Cape Town and G roote Schuur H ospital. t A dapted from a paper delivered at a postgraduate course on "E arly T reatm ent of the Head Injured P atien t" held at the U niversity o f Cape Town, lu ly 1976.
M anagem ent of the secondary effects of brain datnae m ay be prim arily medical, as in the treatm ent of spastj city and epilepsy, or, it may be surgical in which case it m ay fall w ithin the sphere of the general surgeon the orthopaedic surgeon and the neurosurgeon. This com m unication is concerned particularly with the neurosurgical aspects of treatm ent of b rain damage.

PALLIATIVE SURGERY
A t the outset it m ust be clearly stated that surgery cannot be the be-all and end-all of treatm ent of anv patient with brain damage. Surgery is merely a pan of the total m anagem ent and m ust be integrated into the individual treatm ent program m e for the patient M ost o f these operations are destructive procedure" to a greater o r lesser extent and to advise surgery this nature in a patient who already has gross l0i o f function, is a step not to be taken lightly.
R em arkable results following surgery are often due as m uch to the personal attributes o f the patient, his drive and comm itment, as to the surgical procedure. Children with brain damage who have successful operations, usually have parents with the ability to guide their disabled child through his therapy to become a balanced personality despite physical handi caps and their psychological concomitants.

SURGERY OF SPASTICITY
Spasticity is a common result of brain and spinal cord damage in adults and children. It is a release effect from the norm al tonic inhibitory influence on cells which subserve som atic m otor functions. If the basic pathology cannot be affected by treatm ent, therapy is directed at the final common pathw ay subserving muscle tone. It is well known how spasticity can ham per a p atient's progress and how relief of spasticity by physiotherapeutic, medical or surgical means, can at times restore a patient to activities which before w ould have been thought impossible. Non-surgical means o f alleviating spasticity, should be given an ade quate trial before resorting to surgery. T here is no point in adopting a die-hard attitude to some method of treatm ent and stretching the patient on the rack ® that particular method, w aiting for a miracle. If tl. patient is progressively getting worse, denying him the benefit of adequate surgery is as foolish as surgical overenthusiasm.
T he aim s in treatm ent of spasticity are:-1. T o relieve spasticity, and 2. T o retain, if not improve, m otor, sensory or sphincter function. T he final neural pathw ay for spasticity traverses the afferent fibres, the interneurones and efferent neurones at any particular spinal segment. Chemical o r surgical treatm ent is directed at interruption of afferent, inter neuronal or efferent pathways. T reatm ent by tenotomy o r tendon lengthening deals with the mechanical effects of spasticity.

NEURECTOMY
This may be perform ed either by chemical or surgical means and usually interrupts efferent and afferent pathways to a muscle. , nCtion in a nerve has a well-defined place in treating oa.sticity-T he muscle nerve points in question are Realized with stim ulating electrodes and then injected. !?he effects are, however, transient (Cain et al, 1966); (laconibe et al, 1966). Phenol injection into spastic Muscles has been used particularly in m obilising the \L stic arm and hand in hem iplegic patients. T he o b turator nerves m ay be painted at open operation with phenol to relieve adductor spasm.

gurgical Neurectomy
The most frequent operation of this type is ob turator neurectom y for adductor spasm in the legs.
There are a few basic criticism s of neurectomy, the erst being that a peripheral nerve is sectioned. If it is a mixed nerve, there is sensory loss w ith its attendant risks. Irrevocable loss of muscle pow er occurs and muscle wasting and later contracture of the wasted muscle may follow. N eurectom y is not rejected en tirely, but plays a very clearly defined, if limited, p art in the m anagem ent of spasticity.

| R H IZO T O M Y
Surgical P osterior R hizotom y In 1898, Sherrington dem onstrated th at decerebrate rigidity in experim ental anim als could be reduced by posterior nerve-root section. T his effect is due to interruption of afferent input from muscle spindles as well as other receptors.
Foerster in 1908 applied this concept to man by performing posterior root section for spasticity so as to reduce the sensory input w hich propagates spasticity. This involved section of L. 2, 3, 4, 5 and S.l posterior roots. T he idea was to leave some posterior root sensory areas intact as it rapidly became apparent that the sensory loss was a m ajor deficit to some of these patients who were im m obile on account o f their p ara plegia. The beneficial effects, however, were of short duration so that this operation fell into disrepute fairly quickly.
A nterior R hizotom y was introduced by M unro in 1945. It does provide complete relief of flexor spasms but at the price of flaccid paralysis and can therefore only be done below the level of complete cord lesions.
In both these kinds o f rhizotom y, perm anent loss of neural function follows in a person already neurologically disabled, and there is no hope of any re covery ever. Patient selection has therefore to be ex-^emc'l y careful.
Selective A nterior R hizotom y (M unro, 1952) Every second o r third fascicle of the particular nerveroot concerned is divided so as to reduce m otor o u t flow two-o r threefold. If too m any fascicles are divided, flaccid paralysis ensues. It was a valuable method but lacked proper physiological control.

Functional P osterior R hizotom y
To overcom e the difficulties of sensory loss and paralysis following root section, various types of selective posterior root section have been developed [Gros et al (1971), Fraioli & G uidetti (1977]. Fascicles of roots are sectioned according to the effects produced by electrical stim ulation or every fascicle is partially sectioned, or, only 2 or 3 fascicles in a posterior root are left intact. T his is usually done in the lum bar region because not all fascicles are divided or divided com pletely. T here is no extensive sensory loss and no exten sive m otor deficit. This m ethod works on the basis o f reduction in total input w ithout loss o f essential sensa tion, particularly proprioception. W hat is som ewhat surprising at first, is th at there is relief of spasticity at levels higher than the area sectioned, particularly in children w ith cerebral palsy. E xperim ental justification fo r this has been provided by K irk and Denny-Brown (1970). T here is in these children inadequate suppression of input and by re ducing the afferents at a few segments, lessens the total input into the entire nervous system w hich can then function better even at higher levels.
Chemical R hizotom y M aher (1957) treated a series of patients w ith in tra thecal phenol fo r various indications and in this group included a patient w ith severe flexor spasms; T his m ethod was rapidly accepted and developed particularly by N athan (1959,1965). It is a m ethod of treatm ent with considerable risks attached to it if not correctly carried out, but, if the necessary precautions are taken and the injection of the correct strength of phenol solution given under perfect radiological and clinical control, it becomes virtually risk-free. It can allow function to be recovered by rem oval o f disabling spasticity and it can even be given to am bulant patients w ithout producing added neurological deficit. It works on the basis o f non-selective destruction of nerve fibres in the posterior nerve roots w hich consequently reduces the inflow of impulses into the affected segments.
T he disadvantages of the m ethod are, in the first place, the risks attached to it and the danger of im pairing bowel and bladder function. Several roots are affected and undesirable muscle weakness may develop. In some patients the initial satisfactory effects m ay n o t be lasting* To lim it the phenol effect to the desired nerve roots, H arris and Simpson (1964) suggested lam inectom y for these patients and painting of the nerve roots, indi cated by electrical stim ulation, with glycerin and phenol. Even this procedure may be only trarsien tly effective and adds the burden of a lam inectom y to patients rather severely disabled already. Bischoff Type 1 (1951) L ateral longitudinal myelotom y is directed at cutting longitudinally the association fibres of K olliker ru n ning between the anterior and posterior horns and in this w ay interrupting some o f the interneurones con cerned in m aintaining spasticity. L ateral longitudinal incisions are made in the spinal cord, along the line o f the dentate ligaments from L .l to S .l. If the bladder is spastic, one side is cut down to S.5. Bischoff noted that this operation relieved spasticity but tended to interfere with the corticospinal tract and decussating sensory fibres and therefore modified the operation. Bischoff Type 2 (1967) T his is a median posterior longitudinal myelotomy. A n incision is made in the m idline posteriorly to the level of the central canal and lateral extensions are then m ade at right angles to the initial incision in ter rupting the connections between an terior and posterior horns, but w ithout any damage to the corticospinal tracts. A considerable num ber of these operations have been done and the results have been very promising. We have done three with rather satisfactory results and no loss of neurological function. All three patients w ere restored to activities which they had not had before.

CER EB ELLA R D EN T A T O T O M Y
T he effect of cerebellar lesions on tone have been known for a long time. Clinical application of these

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facts to patients with abnorm alities of posture and tone, stems from the w ork of N ashold and Slaughter (1969). The operation is stereotactically perform ed and is based on the theoretical assum ption that in creased output along the dentato-rubrothalam ic path ways can be elim inated by p artial dentate destruction. Im provem ent in spasticity is usually m ore m arked in proxim al than distal muscle groups. T rem or may occur as a com plication of the operation, particularly if the lesion is placed too fa r medially. T his operation has its greatest application in the treatm ent of cere bral palsy (De K lerk, 1973).
T he num ber of procedures available fo r the treat m ent o f spasticity should indicate that n o t one p ro cedure is universally applicable or successful. It has to be emphasized that spasticity is a clinical concept which results from different patho-physiological m echa nisms varying from the site and nature of the lesion(s) in the nervous system.

THE SURGERY OF ABNORM AL MOVEMENTS
C horeo-athetosis is common in children as p art of the cerebral palsy syndrome. T hey do not only have disturbing abnorm al movem ents but also abnorm alities of posture. The evolution of the surgical treatm ent of these children is a long and fascinating one, beginning in 1890 when Sir V ictor H orsley partially excised the prefrontal m otor area in a child with severe hemiathetosis with tem porary relief. H e suggested th at the entire m otor area should have to be excised for perm anent effect on movement. In 1907 he reported another child with hem iathetosis who had perm anent loss of spasmodic movements w ith partial recovery of movem ent of the left arm , after the initial post operative paralysis but had perm anent sensory loss on the left.
T his operation was more o r less forgotten except fo r sporadic reports till 1932, when Bucy and Buchanan revived this w ork by subpial excision of the m otor and prem otor strips w ith some success and noted that the dystonic movements were less favour ably affected than the choreic (Bucy, 1951).
A ny cortical operation left the patient not only w ith some weakness w hich could perhaps be regarded as a reasonable exchange but also with a very real risk of added post-traum atic epilepsy. Occasionally, however, patients had better m otor function after operation than before.
A m ore lim ited attack on the so-called pyram idal tract was directed at the corticospinal m otor tracts in the cerebral peduncles (Walker, 1949). This is a difficult operation as the anatom y does n o t con form to the textbook description; even electro stim ulation does not resolve the problem completely. The results are variable and n o t always lasting, but it has retained a certain popularity in the hands of some surgeons (Maspes & Pagni, 1964).

SPINAL TRACTOTOMY
Surgery directed at the upper cervical spine such as anterio r colum n section, has met with little accep tance because of the m otor and sensory deficits in curred when adequate relief of choreo-athetosis was obtained (Putnam , 1942).

BASAL GANGLION SURGERY
D irect surgical attack on the basal ganglia in the treatm ent of dyskinesias, was pioneered by Meyers (1942). W ith the developm ent o f stereotactic surgery, this m ethod became the accepted way of dealing with m ovem ent disorders. T he advantages are that a small lesion m ay be accurately placed in a nre determ ined target such as the globus pallidus 0|! ventro-lateral nucleus of the thalam us w ithout daman ing the m otor or sensory tracts. By 1953, Narabayash' could report that about 50% of the first group J choreo-athetotic patients treated by chemopallidectomv were im proved and in 1962, he reported a 78% j J ' provem ent in children with cerebral palsy and movement disorders.
Only children w ithout evidence of spasticity and 0f near norm al intellect, are suitable candidates f0r thalam otom y, which may aggravate spasticity. Most authors believe that dystonic and choreiform movements are helped m ore than athetosis by thalamotomy In o ur experience w ith two patients, dystonia has rei sponded extremely well to venrolateral stereotactic thalam otom y.

SURGERY FOR SEIZURES
A n area of cerebral tissue may be destroyed by a wide variety of pathological processes such as vasculr* occlusion, haem orrhage, inflam matory lesions, m ech a n * cal traum a or com pression by any expanding intra'. cranial mass. W hen this destroyed area heals, func tional norm ality does not necessarily return and it may become an epileptogenic focus. It should be noted that the epileptic discharge does no t originate in the lesion but in the border zone between it and normal brain. Usually, such a focus lies in the cortex.

Indications for Surgery
A focal lesion producing partial or generalized epilepsy such as a brain tum our, A-V malformation, cyst o r abscess, w hich can be rem oved safely and with minim al additional surgical trauma. Usually, these patients are operated upon because of cerebral com pression rath er than epilepsy, which is regarded as incidental and symptomatic.
Epilepsy which is uncontrollable medically, and which originates from a localized focus that can be rem oved w ithout producing new neurological deficit. Rem oval is best done by hem ispherectom y or cortical scar excision.

Hemispherectomy
A small group of children with infantile hemiplegia developed intractable epilepsy and later severe b&. havioural disturbances. The cause of the hem ipler'^ may vary. The epilepsy may be partial or generalize, but, usually the latter. B ehaviour disturbances are the most notable feature of this disorder: tem per tan trums, violence, cruelty towards w eaker individuals, and lack of discipline are the outstanding features. There are gross E EG abnorm alities and plain X-rays show asym metry of the skull while air studies reveal marked unilateral ventricular enlargement.
F o r this kind of problem , K rynauw (1950) performed hemispherectomy, rem oving the alm ost completely destroyed hemisphere. A large num ber of cases have been reported (M cKissock 1953(M cKissock , W ilson 1970. D e sp ite occasional late deaths due to haem orrhagic complica tions, 2 out of 3 o f the survivors are seizure-free and a fu rth er 14% much im proved. It is probably the most radical and also the most successful operation fo r epi lepsy. It does not add to the p atient's neurological deficit, which may indeed be lessened. The success with this pioneering operation, led to Penfield's w ork on tem poral lobe epilepsy as a result of which patients w ith this type of epilepsy, are the ones most likely to benefit from surgery in the form o f tem poral lobectomy, provided that the c o r r e c t indications are adhered to. T here is a very low m ortality in this type o f surgery "A the success rate (total abolition or m arked reducf on in seizures) is about 5 0 % -7 0 % , but the failure ate is virtually constant. F or success, strict indications m ust be adhered to . Full and adequate medical therapy J!luSt have failed. Careful clinical and laboratory in v e s tig a tio n s must indicate that there is a focal cortical lesion present and the area of cortex involved m ust he dispensable w ithout adding to the p atien t's neuro logical deficit. (Rasmussen, 1969). T here are other forms 0f surgery fo r epilepsy but their results are less p re dictable and their application has not become w ide spread.

Surgery of abnorm al behaviour
Some epileptics develop severe behaviour disorders auch as aggressiveness, extrem e restlessness, destruc tiveness and unprovoked violent behaviour. W hen all medication fails, and the patient can only be insti tutionalised, certain form s of surgery m ay give relief; the "sedative surgery" of Sano. Stereotactic amygdalotomy, cingulotom y and postero-m edial hypothalam otomy have all been reported as being beneficial but this is surgery which should not be. lightly undertaken on a c c o u n t of the m oral and ethical considerations in volved.
t h e s u r g e r y o f r a i s e d i n t r a c r a n i a l PR ESSU R E Brain damage may follow on elevated intracranial pressure as indicated earlier on. T here are two con ditions which deserve special m ention. The commonest is the developm ent of hydrocephalus after any form of cerebral injury and the other is porencephaly.

Hydro ccphalus
Any lesion which leads to obstruction o f the o u t flow of a lateral ventricle, third ventricle, aqueduct or fourth ventricle, or even which leads to obstruc tion of the tem poral horn of one lateral ventricle m ay 'cause a varying degree of hydrocephalus proxim al to S h e level of obstruction. H ydrocephalus produces ^secondary damage due to stretching of the p araventri cular fibres and pressure. The sym ptom s of raised intracranial pressure such as headache, vom iting and papilloedema, are to be watched for. Perhaps m ore im portant than these, although a little m ore subtle, are symptoms such as failure of concentration, intel lectual fall-off and loss of recent m em ory. T he latter ones may present themselves earliest of all to the therapist. T he medical attendant should take heed of these complaints to prevent irreparable brain damage by early surgery. Investigations often show a so-called occult hydrocephalus w here there are no sym ptom s of raised intracranial pressure but only those o f intellec tual im pairm ent, unsteadiness of g ait and incontinence of urine. T here are many methods available fo r treat ing hydrocephalus pressure surgically, and these can be very effective in restoring a patient to norm al life.

Porencephalic Cysts
These cerebral cavities of varied aetiology occur particularly in children. They occur w ithin the cerebral substance and com m unicate w ith the CSF pathways.
Such com m unications may becom e sm aller or blocked off and as fluid is being pum ped into them w ithout any outflow, they become secondarily space demanding. They need early managem ent to prevent fu rth er dam age to the brain which has already suffered conconsiderable injury.

CONCLUSION
A wide range o f clinical conditions and a large num ber of surgical procedures have been mentioned. They may seem confusing, b u t it does indicate the inadequate state of our knowledge and therapy o f the brain damaged individual. C areful patient selection fo r surgery is essential if success is to be expected. F o r this personal contact w ith the patient and a thorough understanding of his problem s m ust be estab lished by the therapeutic team of w hich the surgeon must function as a part.