A C T A O P H T H A L M O L O G I C A VOL. 5 4 1 9 7 6
Neurosurgery Department (Heads: J. Riishede, K . Vaernet, P. Rasmussen, Aa. Harnzsen) and Eye Department, Tagensuej (Heads: B. Lawaetzt, H. H. Seedorff), Rigshospitalet, University of Copenhagen
TEMPORAL LOBE EPILEPSY AND NEURO-OPHTHALMOLOGY Ophthalmological Findings in 74 Temporal Lobe Resected Patients BY
INGE JENSEN and H. H. SEEDORFF
A survey is presented of the ophthalmological findings in 74 patients with drug-resistant temporal lobe epilepsy, who underwent unilateral anterior temporal lobectomy 1960-1969 at Rigshospitalet, Copenhagen. At followup, 1970-1971, one to ten years following the operation, 8lU/o of the patients had no or only few seizures. The visual acuity remained unchanged in all patients following the opwation. Preoperatively a visual field defect was observed in 2 patients. At follow-up 51 patients had homonymous hemianopias, in 38 of them this was limited to the upper quadrants, and in 13 patients also included the lower quadrants, but was characterized as a total homonymous hemianopia in only 6 patients. The presence and extent of the visual field defects were correlated to surgical results, age at onset of epilepsy, age at operation, preoperative duration of epilepsy, presence of grand mal, preoperative complications, and neuropathological findings, but without observing any statistically significant conclusions. On the other hand, the extent of the postoperative visual field defect was significantly influenced by the side of the operation, with more and larger defects following right-sided lobectomies. In the 51 patients with postoperative hemianopias, this defect was either unobserved by the patient or regarded as a considerably less important handicap than the frequent and socially invalidating preoperative seizures. This study was supported by grants from The Danish Foundation for the Advancement of Medical Science and the Danish Epilepsy Association. Received August 10, 1976.
827
Inge Jensen and I I . Ii. Seedorlf
Preoperatively 11 Oio of the patients had suffered from strabismus as compared to an expected frequency of 5 Oio, but this trend just falls short of statistical significance.
Key words: temporal lobe epilepsy - temporal lobe resection - visual acuity - visual field defect - congruity - macular involvement strabismus.
Unilateral anterior temporal lobectomy has since 1948 proved to be a n excellent form of treatment for drug-resistant temporal lobe epilepsy of unilateral or predominantly unilateral origin. To date surveys covering more than 2000 operations have been published (Inge Jensen 1975a; Van Buren et al. 1975). In summary, the outcome is that two-thirds of the patients at follow-up, one to ten years after the operation, had no or only few seizures, and in more than three-quarters of the patients the operation could be described as “worthwhile”. Furthermore, over half of the patients, who preoperatively had displayed some psychiatric disorders, were normalized or had markedly improved. Homonymous hemianopic visual field defects were found to be frequent sequelae of this operation (Guillaume 8i Mazard 1956; Brown et al. 1956; Bailey 1954; Falconer & Wilson 1958; Van Buren & Baldwin 1958; Walker & Walsh 1958; Falconer 8: Serafetinides 1963; Davis 1963; Green & Scheetz 1964; Hullay 1965; Green 1967; Marino & Rasmussen 1968). The study of these visual field defects has contributed to the elucidation of the anatomy of the visual pathways in the temporal region of the brain. Previously the knowledge of the visual pathways was largely based on visual field defects observed in patients with tumours (e.g. Cushing 1922; Oldberg 1937; Edmund 1954) or with traumatic lesions, especially gun shot wounds, but in these patients the intracerebral lesion was seldom well-defined. In contrast to those lesions an anterior temporal lobectomy is a well-defined lesion. Investigations of the patients with such lesions have made it possible to verify the theories about the visual pathways in this area (Falconer 8i Wilson 1958; Van Buren & Baldwin 1958; Marino & Rasmussen 1968; Walker & Walsh 1968). These authors have correlated the visual field defects to the extent of the operation and the surgical results and thus tried to map out the visual pathways. The present investigation cannot, with regard to the visual pathways, in any way supplement the information furnished by these authors. W e have tried to present a compiled analysis of the ophthalmological status, preoperatively and at follow-up, the purpose of the investigation being to correlate the ophthalmological findings to the surgical results and to other clinical aspects.
828
Temporal Lobe Epilepsy and Neuro-ophthalmology
The surgical treatment of drug-resistant temporal lobe epilepsy was instituted in Denmark in 1960, and by the end of March 1975 a total of 106 patients had been submitted to an anterior temporal lobe resection (Inge Jensen PC Vaernet 1976). Operative method
The operation consisted of an anterior temporal lobectomy, usually going back to the vein of Labbt, the extent of the excision ranging from 5.5 to 7 cm. Where no welldefined vein of Labbt existed, or where it ran posterior to this limit, the excision was carried back to a point 6 cm from the temporal pole in the dominant hemisphere and 7 cm in the non-dominant hemisphere. The superior temporal gyrus, apart from the anterior 2 cm, was preserved in order to minimize the risk of postoperative dysphasia. All operations but one were performed by Kjeld Vaernet, who followed the principles laid down at the Guy’s-Maudsley Hospital by Falconer (Falconer et al. 1955; Falconer 1965), resecting the tip of the temporal lobe including the mesial structures en bloc so that the whole specimen was available for histological examination. Case material
The present material consists of the first 74 patients with drug-resistant temporal lobe epilepsy, who during the period 1960-1969 were treated with unilateral temporal lobe resection of University Clinic of Neurosurgery, Rigshospitalet, Copenhagen. Neither before nor during the operation was any tumour or gross vascular malformation recognized in any of the patients. All patients suffered from psychomotor and/or focal seizures originating from the temporal lobe, and 55 of them also had grand mal. Their epilepsy was extremely severe and preoperatively all of them were socially handicapped due to their frequent and severe seizures and/or psychiatric disturbances. In all patients a unilateral or predominantly unilateral spike discharging temporal focus was demonstrated in routine EEG scalp recordings with sleep recordings or recordings with sphenoidal electrodes. The material comprises 43 males and 31 females. At the time of the operation the ages of the patients ranged from 4-54 years, with 14 of them being 15 years or younger. The median follow-up period was 5.1 years. In 60 of the patients the preoperative duration of epilepsy was more than 4 years. A retrospective follow-up investigation was undertaken in 1970-1971 covering various clinical, genetical, aetiological, social, psychological, neuropathological and electroencephalographic aspects. Some of these results have been already published (Inge Jensen 1975a,b,c, 1976a,b; Inge Jensen & Klinken 1976; Inge Jensen & Vaernet 1976). The overall effect of the operation on the seizures was found to be that 61”/0 of the patients were free from any seizures, 20 O/o had obtained a reduction in their seizure frequency by at least 75O/o, while the remaining 190/0 belong to the group “no change”, which comprises some reduction in seizure frequency, no change, and the four postoperative deaths (Table I). Table I also indicates that a unilateral temporal lobectomy favourably influences the psychiatric status, as one third of the patients were found to be without any psychiatric abnormality at the follow-up investigation as compared to one-eighth at the time of the operation, and further that another third showed marked psychiatric improvement.
829 Acta ophthal. 54, G
54
lnge Jensen and H . H. Seedorff Table 1. Effect of temporal lobe resection on seizures versus psychiatric status at follow-up.
Marked Some No No seizures reduction reduction change
Death
Total
Psychiatric status
Normal (pre- and postop.) (only postop.
4 11
2 4
0 0
0 1
0 0
6 8 O/o 16 22 O / o
Abnormal Markedly improved Improved
13 3
5 1
1 1
1 0
0 0
20 27 O / o 5 7 o/o
Unchanged/deteriorated (abnormal preop.) 11 (normal preop.) 3
3 0
2 1
2 1
4
22 30 O/o 3 7 o/o
5 7 O/o
4 5 O/o
4 5O/o 74 100°/o
Total
45 61 O/o
15 20°/o
0
As previously stated, this investigation is retrospective, but all patients, provided they could cooperate, were routinely examined immediately prior to the operation and one week postoperatively at the University Clinic of Neuroophthalmology, Rigshospitalet. It can further be noted that these 74 patients prior to the operation were examined by ophthalmologists o n 8 a total of at least 343 occasions during their hospital admissions, and on a further 245 occasions postoperatively, not including the examination at the follow-up investigation, which was also performed at the University Clinic of Neuroophthalmology, Rigshospitalet. The neuro-ophthalmological examinations generally included: 1) visual acuity, 2) eye position and eye movements, and pupillary conditions, 3) ophthalmoscopy, 4) visual field examination by campimetry (Bjerrum)
and these examinations were, if necessary, supplemented with others. At the follow-up investigation, 1970-7 1, all 70 surviving patients were examined clinically. Due to various irrelevant causes the ophthalmological examinations were not carried out in four patients (Nos. 16, 18, 46 and 62). The visual field has post830
Temporal Lobe Epilepsy and Neuro-ophthalmology operatively been recorded as normal in two of these (Nos. 18 and 62), in one (No. 16) a total homonymous hemianopia was recorded postoperatively, a defect which was still present and inconvenient to the patient; the last of these patients (No. 46), an autistic and imbecile boy could not cooperate but reacted normally to threats from various visual angles. Two of the four deceased patients were never examined postoperatively (Nos. 4 and 6), one (No. 35) had had normal postoperative examinations, while in the last patient (No. 32) a right-sided homonymous anopia affecting the upper quadrants had been described. The neuro-ophthalmologiczsl case material includes a total of 69 patients (Table 11).
Results of Neuro-Ophthalmological Examinations Visual acuity
At follow-up all patients were found to possess the same visual acuity as preoperatively.
Side of operation left N = 35
N o visual field defect Visual field defect present No examination
11 26 2
7 25 3
18 51
Extent of visual field defect affecting only upper quadrants partly including lower quadrants total hemianopia
15 6 5
23 1 1
38 7 6
Congruity of visual field defects Incongruity of visual field defects
15 11
14 92)
29 20
8
3
11
Macular involvement 1)
2)
Total N=74
right N=39
51)
Cases Nos. 4, 6, 32, 35 and 46. 2 patients have been excluded (Case No. 2 due to impaired cooperation, Case No. 5 due to choroidal tumour).
83 1 54"
Inge Jensen und H. H . Seedorff Visual field defects
Numerically and clinically the most important finding has been the postoperative visual field defect, which, as a homonymous hemianopia of a vaying extent, was present in 51 of the 69 patients examined. Preoperatively homonymous hernianopia was present in two patients (Nos. 29 and 76); this was completely unchanged at follow-up. While the occurrence of a postoperative hemianopia was independent of the side of the operation (Table 11), 7 1 O/O in right-sided temporal lobectomies and 73 O / O in left-sided, the extent of the anopia was significantly influenced by the side, as the lower quadrants were affected in 1 1 patients (i. e. 29 O/O) operated upon the right side as compared to two patients (i. e. 6 O/O) operated upon the left. In six patients the visual field defects were total hemianopias, only one of these was operated on the left (No. 16). The finding that the left-sided anopias are more extensive, is presumably due to the extent of the lobectomy, which was generally greatest on the right side (Inge Jensen & Vaernet 1976). When calculating the extent of the visual field defects it was found that the left-sided defects were approximately 300/0 larger than the right-sided. The difficulties in recognizing whether the observed visual field defects are congruent or non-congruent are mainly due to the fact that the horizontal borders can be difficult to define. It is generally acknowledged that the vertical border is always sharp. By contrast the horizontal border tends to be sloping, to a degree which varies according to the isopter used. The establishment of standards for congruity versus incongruity has been attempted by Van Buren & Baldwin (1958). According to these authors congruity is present when the difference between the extent of the visual field defects is less than 5' on repeated examinations. Observing these standards we found congruent visual Eield defects in 29 of the 49 patients with visual field defects at follow-up (i. e. 59 0/0), a number which corresponds with the 61 O / O observed by Walker & Walsh (1968) in their 18 patients. The question of congruity versus non-congruity of the visual field defects has also been investigated, as shown in Table 2, without any positive conclusions being reached. In accordance with Falconer & Wilson (1958), Van Buren & Baldwin (1958), Marino & Rasmussen (1968) and Walker & Walsh (1968) we observed that, with few exceptions, the visual field defects were consistently most marked on the ipsilateral side with the difference on average amounting to 5 O/O. The vision was unchanged postoperatively in all patients, but in eleven of them the visual field defect was found to be so centrally localized that involvement of the macula must have occurred. 832
Temporal Lobe Epilepsy and Neuro-ophthalmology
It is worth noting that a visual field defect affecting the upper quadrant only is in most cases unnoticed by the patient and not revealed until the neuro-ophthalmological examination, as already observed by Rsnne (1915). On the other hand, a visual field defect involving the lower quadrants will severely inconvenience the patient, and might for example prevent the patient from obtaining a driving license, as was the case in 13 of the patients.
Age at onset of epilepsy
Presence of grand ma1 %
01-
100 80 60
LO 20 n "
0-4 5-9 10-14 15-19 320 years Preoperative duration of epilepsi
No grand ma1
Grand ma!
Neuropathological lesion
% I""
80 60 LO
20 0 0 - L 5-9 10-11. 315
i]no
defect
0upper quadrants
years
1
2
3
L
upper and p a r t l y [3 lower quadrants
1
focal
2
total hemianopia
3
equivocal
L coagulation
disseminated
Fig. 1.
The presence and extent of postoperative visual field defects correlated to various clinical variables.
833
Inge Jensen and If. H. Seedorjf Table I I I . Visual field defects correlated to various variables (69 pafients available for examination). Visual field defect
1 Surgical results no seizures still seizures A g e at onset of epilepsy < 15 years 2 15 years Age at operation 5 15 years > 15 years Preoperative duration of epilepsy < 10 years 2 10 years Grand ma1 present absent
present N=51
75O/o 72 O / o
11 7
25 O / o 28 O/o
36 15
80 O / o 63 OIo
9 9
20'Olo 38 O / o
7
54 010 79 '10
6 12
46O/o 21 010
35
62 OIo 81 010
10 8
38 O/o 19 o/o
39 12
78 OIo 63 O / o
11 7
22 010 37 010
8 43
89 010 72 OIo
1 17
11 010 28O/o
23 7 9 12
85 O / o 58 OIo 53 010 92 O/o
4 8 1
15 O / o 42 O/o 47 010 8 010
8 100 010 43 70 O/o
0 18
30 O/o
16
Strabismus present absent
absent N=18
33 18
44
Peroperative coniplications present absent Neuropathology disseminated focal questionably abnormal previous coagulation
I
5
The presence of a postoperative visual field defect has been correlated to various clinical aspects, as shown in Fig. 1 and Table 111. The presence or absence of a visual field defect does not in any way prognostically influence the surgical outcome regarding relief from seizures, but, with an increase in 834
Temporal Lobe Epilepsy and Neuro-ophthalmology
the extent of the visual field defect, an increase in the number of seizurefree patients is observed: No visual field defect - 61 O/O seizure-free patients, a visual field defect involving the upper quadrants alone - 62 O/O seizure-free patients, and a visual field defect also involving the lower quadrants - 69 O/o seizure-free patients. This trend is, however, not statistically significant. Apparently, it would seem that preoperative presence of grand ma1 seizures, young age at onset of epilepsy, a long preoperative duration of epilepsy and consequently higher age at operation, peroperative difficulties with the haemostasis, and preoperative strabismus promote the occurrence of a postoperative visual field defect, but these trends are not statistically significant. With regard to the neuropathological findings it is observed that the more diffuse and disseminated the lesion, the higher the incidence of visual field defects. Strabismus
A total of eight patients (i. e. 10.8 O/O) had strabismus, all of whom were submitted to operative correction. This incidence was considerably highly than expected from the incidence in normal school children of 4.50/0 (Anna D. Frandsen 1960), but the difference is not statistically significant. She also
Table IV. The presence of strabismus correlated to various clinical variables. Strabismus present
absent
N=S
N=66
Surgical results no seizures marked reduction no change
7 1 0
38 14
Predisposition to neurological disease present absent
2 6
34
Perinatal complication present absent
3 5
25
835
14
32
41
Inge Jensen and H. H. Seedorff
found an increasing incidence of strabismus with decreasing intellectual levels. Our findings are in full accordance with Millar (1965), who, in his material of 401 patients with epilepsy, observed an incidence of 10 O/O. He concluded that the tendency to squint was more closely correlated to birth injuries than to the severity of the epilepsy. This conclusion could not be substantiated by the pesent investigation. Apparently the presence of strabismus favourably influences the surgical prognosis regarding relief from seizures, but this trend is definitely not statistically significant (Table IV).
Discussion Wilbrand (1890) was one of the first to describe the architecture of the visual pathways, and with regard to their course in the temporal lobe he stated that the visual pathways after their departure from the lateral geniculate bodies divide into three bundles, a superior horizontal bundle comprising nerve fibres from the homonymous superior half of the retina, an inferior one comprising nerve fibres from the inferior part of the homonymous half of the retina, and lastly an intermediary bundle, which is displaced somewhat medially and which contains nerve fibres from the corresponding homonymous macula areas. Meyer (1907) was of the opinion that the inferior (ventral) nerve fibres, after the departure from the lateral geniculate bodies, bend forward and pass round and over the temporal horn of the lateral ventricle, “Meyer’s loop”, before they continue backwards down into the inferior part of the temporal lobe and into the lateral wall of the lateral ventricle to join the two other bundles, mentioned previously, on their common path to the occipital lobe. Ranne (1915, 1919, 1938) in his concept of the visual pathways in the temporal lobe was in full agreement with the authors mentioned above. He based his observations on clinical case histories, and one of his conclusions was that a visual field defect in upper homonymous quadrants must be a symptom of a lesion in the temporal lobe affecting Meyer’s loop. As one of the first Ranne (1915) discussed the question of congruity versus non-congruity in lesions in the temporal lobes. Rsnne (1915) and Harrington (1939), among others, advocated the concept that the course of the nerve fibres in the visual pathways in the temporal lobe is subject to extremely marked individual variations. Ranne (1915), Traquair (1922, 1949) and Falconer & Wilson (1958), were of the opinion that lesions in the temporal lobe generally result in congruity of the visual field defects, and that the demarcation lines will as a rule be sharp. In contrast Gushing 836
Temporal Lobe Epilepsy and Neuro-ophthalmology
j1922), based on his own operative experience, was of the opinion that incongruity is predominant following lesions in the temporal lobe; due to the anatomical fact that the homonymous nerve fibres had not yet joined each cther. Furthermore, he was of the opinion that the horizontal inferior border of the visual field defect was always sloping. As previously mentioned, the study of the visual field defects after welldefined temporal lobe resections in drug-resistant temporal lobe epilepsy has presented the best information to date concerning the architecture of the visual pathways. Investigations by Van Buren & Baldwin (1958) and Walker & Walsh (1968) supported the concept that operative lesions in the temporal lobe generally result in incongruity of the visual field defects. Walker & Walsh (1968) asserted that this point of view is supported by the results from studies on the retrograde degeneration of nerve cells in the lateral geniculate corpora following lesions in the optic radiation and the striate area, respectively. These studies would, according to Walker & Walsh (1968), also account for the fact that the vertical demarcation of the visual field defect always is sharp, while the horizontal tend to be sloping. R0nne (1915) was very interested in the difficulties in determining the horizontal border in visual field defects. This difficulty is probably the main reason for the as yet unresolved divergences concerning the concept of congruity. It is generally agreed that the vertical border is always sharp, independent of the isopters used, while on the other hand there can be considerable variations in the horizontal border. This horizontal borderline zone might, depending upon the isopters, assume a fan-like appearance, which, in incongruity, might appear as a relative defect on one side, and as an absolute defect on the other for the same object. The question of congruity versus incongruity is also a question of accepting a rigid and more and less arbitrary standard of 5' with regard to the horizontal borderline. Like Walker & Walsh (1968), we are disinclined to accept a ruling that visual field defects should be considered congruent when a difference of 5' is accepted. W e therefore agree with Harrington (1939) and M7alsh & Hoyt (1969), who conclude that the more posterior the localization of the lesion, the more the visual field defects approach congruity, becoming definitely congruent in lesions close to the striate area. The reason for the incongruity, or at any rate questionable congruity, in lesions in the temporal lobe as compared to a definite congruity in lesions in the occipital lobe, is that the corresponding nerve fibres from the homonymous retinae anatomically complete their fusion very close to the striate area. The presence or the extent of the visual field defects is largely dependent upon the extent of the operative lesion, as demonstrated by Harrington (1961), a37
Inge Jensen and H . H . Seedorff
who observed that resections performed 8 cm or more from the tip of the temporal pole very frequently resulted in total hemianopia. This complication might also be due to disturbances of the blood supply to the visual pathways. Following the operation the visual acuity is very seldom disturbed, even in the very few cases in the present material in which there was a suspicion of macular splitting. This is probably due to the fact that the homonymous fibres from the macula, in the temporal lobe, are localized medially in the optic radiation and thus close to important cerebral areas which the neurosurgeon attempts to spare during the operation, for example the posterior parts of the superior temporal gyrus. The importance of the extent of the lobectomy has also been demonstrated in the present material where the number of visual field defects including the lower quadrants is significantly higher in the right-sided lobectomies than in the left-sided (Table 11),2 and 11 per cent respectively, which corresponds well with the fact that right-sided lobectomies are generally larger than leftsided. Apart from this finding, we, like Falconer & Wilson (1958), have not found any significant correlations between the extent of the lobectomy and the degree of the anopia. As mentioned previously, 33 O/O of the patients had retained their normal visual fields following resections varying in extent from 5.5 to 7 cm. Also in accordance with these authors we observed that an opening of the tip of the lateral ventricle did not necessarily result in a postoperative visual field defect. The individual variations in the course of Meyer’s loop, as suggested by Renne (1915), can explain this observation.
Conclusion With regard to the architecture of the visual pathways in the temporal lobe, the present investigation is in full agreement with surveys previously published. Primarily the purpose was not to attempt to supply new information about the anatomy of the visual pathways, but rather, based on clinical observations, to correlate the importance of anterior temporal lobectomy in the treatment of drug-resistant temporal lobe epilepsy with the ophthalmological complications which might result from this operation, and above all to the homonymous visual field defects. This topic is a typical borderline subject between the two related specialities, neurology and ophthalmology. From the neurological point of view a unilateral temporaI lobectomy has proved to be successful in relieving patients with drug-resistant temporal lobe epilepsy of their seizures and has in many cases also made a social rehabilitation possible. From the ophthalmolo838
Temporal Lobe Epilepsy and Neuro-ophthalmology
gical point of view a visual field defect was found to be a postoperative complication in two-thirds of the patients, but in the majority of these cases it was of only minor importance (viz. the visual field defects affecting the upper quadrants only). Based on the knowledge accumulated in literature during the last 60 to 70 years, and on our own experience, it must be emphasized that very marked individual variations are observed in the course of the visual pathways in the temporal lobe, especially regarding the Meyer’s loop, even though there is correlation between the extent of the temporal lobe resection and the postoperative presence of a visual field defect. Accordingly it is not possible to predict whether a visual field defect will occur or not, not can the extent of any postoperative defect be predicted. If the relatively few cases (13 of 74) with visual field defects including the lower quadrants are set against the satisfactory results regarding relief from seizures and social rehabilition, most importance must be attached to these results, provided that the visual acuity remains unaffected. The present investigation also supports the opinion that this operation should preferably be carried out in childhood, adolescence, or early adulthood, and should definitely be undertaken as soon as the epilepsy has proved to be resistant to medication.
References Bailey P. (1954) Betrachtungen iiber die chirurgische Behandlung der psychomotorischen Epilepsie. Zbl. Neurochir. 14, 195-206. Brown I. A,, French L. A., Ogle W. S. & Johnson S. (1956) Temporal lobe epilepsy; its clinical manifestations and surgical treatment. Medicine 35, 425459. Cushing H. (1922) The field defects produced by temporal lobe lesions. Bruin 44, 431-442. Davis E. (1963) A review of the features and treatment of temporal lobe epilepsy; with special reference to surgery. Proc. Aust. Ass. Neurol. I , 27-30. Edmund J. (1954) Visual disturbances associated with gliomas of the temporal and occipital lobes. Acta psychiat. scand. 29, 291-310. Falconer M. A. (1965) The surgical treatment of temporal lobe epilepsy. Nezsrochirurgia (Stuttg.) 8, 161-172. Falconer M. A., Hill D., Meyer A., Mitchell W. & Pond D. A. (1955) Treatment of temporal lobe epilepsy by temporal lobectomy. Lancet I, 827-835. Falconer M. A. & Serafetinides E. A. (1963) A follow-up study of surgery in temporal lobe epilepsy. /. Neurol. Neurosurg. Psychiat. 26, 154-165. Falconer M. A. & Wilson J. L. (1958) Visual field changes following anterior temporal lobectomy. Brain 81, 1-14. Frandsen Anna D. (1960) Occurrence of squint. Copenhagen 1960. Thesis, 151.
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Inge /ensen. and H . H. Seedorff Green J. R. (1967) Temporal lobectomy; with special reference to selection of epileptic patients. J . Neurosurg. 26, 584-593. Green J. R. & Scheetz D. G. (1964) Surgery of epileptogenic lesions of temporal lobe. Arch. Neurol. (Chicago) 10, 135-148. Guillaume J. & Mazard G. (1956) Indication et rksultats du traitement chirurgical des epilepsies temporales. Sem. H6p. Paris 32/2, 2013-2018. Harrington D. 0. (1939) Localizing value of incongruity in defects of visual fields. Arch. Ophthal. (Chicago) 21, 453-467. Harrington D. 0. (1961) The character of visual field defects in temporal and occipital lobe lesions, localizing value of congruity and incongruity in incomplete homonymous hemianopsia. Trans.amer. ophthal. SOC.59, 333-345. Harrington D. 0. (1971) The Visual Fields, p. 304-308. C. V. Mosby, St. Louis. Hullay J. (1965) Surgical treatment of temporal lobe epilepsy. Acta med. Acad. Sci. hung. 7, 295-320. Jensen Inge (1975a) Temporal lobe surgery around the world. Results, complications, and mortality. Acta neurol. scand. 52, 354-373. Jensen Inge (197513) Temporal lobe epilepsy. Late mortality in patients treated with unilateral temporal lobe resection. Acta neurol. scand. 52, 374-380. Jensen Inge (1975~)Genetic factors in temporal lobe epilepsy. Acta neurol. scand. 52, 381-394. Jensen Inge (1976a) Temporal lobe epilepsy. Etiological factors and surgical results. Acta neurol. scand. 53, 103-118. Jensen Inge (1976b) Temporal lobe epilepsy. Social conditions and rehabilitation after surgery. Acta neurol. scand. 54, 22-44. Jensen Inge & Klinken L. (1976) Temporal lobe epilepsy and neuropathology. Acta neurol. scand. 54, in press. Jensen Inge & Vaernet K. (1976) Temporal lobe epilepsy. Follow-up investigation of 74 temporal lobe resected patients. Acta neurochir. ( W i e n ) , in press. Marino R. & Rasmussen T. (1968) Visual field changes after temporal lobectomy in man. Neurology (Minneap.) 18, 825-835. Meyer A. (1907) The connections of the occipital lobes and the present status of the cerebral visual affections Tians. Ass. Amer. Phycns 22, 7-16. Millar J. H. D. (1965) Epilepsy and strabismus. Epilepsia 6, 43-46. Oldberg S. (1937) Versuch zur Erklarung der Quadrantanopsie bei Schlafenlappentumor. Acta rned. scand. 93, 330-345. Rsnne H. (1915) Ueber die Inkongruens und Asymmetrie in dem homonymen hemianopischen Gesichtsfeld. Klin. Mbl. Augenheilk. 54, 309-325. Rsnne H. (1919) Ueber die Quadranthemianopsie und die Lage der Maculafacern in dem occipitalen Sehbahn. Klin. Mbl. Augenheilk. 63, 358-365. Rsnne H. (1938) The focal diagnostic of the visual pathways. Acta ophthal. (Kbh.) 16, 446-456. Traquair H. M. (1922) The course of the geniculocalcarine visual pathways in relation to the temporal lobe. Brit. /. Ophthal. 6, 251-261. Traquair H. M. (1949) A n Introduction to Clinical Perimetry, 6th ed. C. V. Mosby, St. Louis, 212-245. Van Buren J. M. & Baldwin M. (1958) The architecture of the optic radiation in the temporal lobe of man. Brain 81, 15-40.
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Temporal Lobe Epilepsy and Neuro-ophthalmology Van Buren J. M., Ajmone-Marsan C., Mutsuga N. & Sadowsky D. (1975) Surgery of temporal lobe epilepsy. In: Purpura D. P., Penry J. K. and Walter R. D., Eds. Advances in Neurology, Vol. 8, pp. 155-196. Raven Press, New York. Walker A. E. & Walsh F. B. (1968) Neuro-ophthalmological Symposium, p. 249-268.' C . V. Mosby, St. Louis. Walsh F. B. & Hoyt W. F. (1969) Clinical Neuro-ophthalmology, 3rd ed., 2185-2214. Williams & Wilkins Comp., Baltimore. Wilbrand H. (1890) Die Hemianopsiegeschichtfeldformen.Wiesbaden.
Author's address: Inge Jensen, M. D., Department of Neuromed., Glostrup Hospital, DK-2600 Glostrup, Denmark.
84 1
Neurosurgery Department (Heads: J. Riishede, K . Vaernet, P. Rasmussen, Aa. Harnzsen) and Eye Department, Tagensuej (Heads: B. Lawaetzt, H. H. Seedorff), Rigshospitalet, University of Copenhagen
TEMPORAL LOBE EPILEPSY AND NEURO-OPHTHALMOLOGY Ophthalmological Findings in 74 Temporal Lobe Resected Patients BY
INGE JENSEN and H. H. SEEDORFF
A survey is presented of the ophthalmological findings in 74 patients with drug-resistant temporal lobe epilepsy, who underwent unilateral anterior temporal lobectomy 1960-1969 at Rigshospitalet, Copenhagen. At followup, 1970-1971, one to ten years following the operation, 8lU/o of the patients had no or only few seizures. The visual acuity remained unchanged in all patients following the opwation. Preoperatively a visual field defect was observed in 2 patients. At follow-up 51 patients had homonymous hemianopias, in 38 of them this was limited to the upper quadrants, and in 13 patients also included the lower quadrants, but was characterized as a total homonymous hemianopia in only 6 patients. The presence and extent of the visual field defects were correlated to surgical results, age at onset of epilepsy, age at operation, preoperative duration of epilepsy, presence of grand mal, preoperative complications, and neuropathological findings, but without observing any statistically significant conclusions. On the other hand, the extent of the postoperative visual field defect was significantly influenced by the side of the operation, with more and larger defects following right-sided lobectomies. In the 51 patients with postoperative hemianopias, this defect was either unobserved by the patient or regarded as a considerably less important handicap than the frequent and socially invalidating preoperative seizures. This study was supported by grants from The Danish Foundation for the Advancement of Medical Science and the Danish Epilepsy Association. Received August 10, 1976.
827
Inge Jensen and I I . Ii. Seedorlf
Preoperatively 11 Oio of the patients had suffered from strabismus as compared to an expected frequency of 5 Oio, but this trend just falls short of statistical significance.
Key words: temporal lobe epilepsy - temporal lobe resection - visual acuity - visual field defect - congruity - macular involvement strabismus.
Unilateral anterior temporal lobectomy has since 1948 proved to be a n excellent form of treatment for drug-resistant temporal lobe epilepsy of unilateral or predominantly unilateral origin. To date surveys covering more than 2000 operations have been published (Inge Jensen 1975a; Van Buren et al. 1975). In summary, the outcome is that two-thirds of the patients at follow-up, one to ten years after the operation, had no or only few seizures, and in more than three-quarters of the patients the operation could be described as “worthwhile”. Furthermore, over half of the patients, who preoperatively had displayed some psychiatric disorders, were normalized or had markedly improved. Homonymous hemianopic visual field defects were found to be frequent sequelae of this operation (Guillaume 8i Mazard 1956; Brown et al. 1956; Bailey 1954; Falconer & Wilson 1958; Van Buren & Baldwin 1958; Walker & Walsh 1958; Falconer 8: Serafetinides 1963; Davis 1963; Green & Scheetz 1964; Hullay 1965; Green 1967; Marino & Rasmussen 1968). The study of these visual field defects has contributed to the elucidation of the anatomy of the visual pathways in the temporal region of the brain. Previously the knowledge of the visual pathways was largely based on visual field defects observed in patients with tumours (e.g. Cushing 1922; Oldberg 1937; Edmund 1954) or with traumatic lesions, especially gun shot wounds, but in these patients the intracerebral lesion was seldom well-defined. In contrast to those lesions an anterior temporal lobectomy is a well-defined lesion. Investigations of the patients with such lesions have made it possible to verify the theories about the visual pathways in this area (Falconer 8i Wilson 1958; Van Buren & Baldwin 1958; Marino & Rasmussen 1968; Walker & Walsh 1968). These authors have correlated the visual field defects to the extent of the operation and the surgical results and thus tried to map out the visual pathways. The present investigation cannot, with regard to the visual pathways, in any way supplement the information furnished by these authors. W e have tried to present a compiled analysis of the ophthalmological status, preoperatively and at follow-up, the purpose of the investigation being to correlate the ophthalmological findings to the surgical results and to other clinical aspects.
828
Temporal Lobe Epilepsy and Neuro-ophthalmology
The surgical treatment of drug-resistant temporal lobe epilepsy was instituted in Denmark in 1960, and by the end of March 1975 a total of 106 patients had been submitted to an anterior temporal lobe resection (Inge Jensen PC Vaernet 1976). Operative method
The operation consisted of an anterior temporal lobectomy, usually going back to the vein of Labbt, the extent of the excision ranging from 5.5 to 7 cm. Where no welldefined vein of Labbt existed, or where it ran posterior to this limit, the excision was carried back to a point 6 cm from the temporal pole in the dominant hemisphere and 7 cm in the non-dominant hemisphere. The superior temporal gyrus, apart from the anterior 2 cm, was preserved in order to minimize the risk of postoperative dysphasia. All operations but one were performed by Kjeld Vaernet, who followed the principles laid down at the Guy’s-Maudsley Hospital by Falconer (Falconer et al. 1955; Falconer 1965), resecting the tip of the temporal lobe including the mesial structures en bloc so that the whole specimen was available for histological examination. Case material
The present material consists of the first 74 patients with drug-resistant temporal lobe epilepsy, who during the period 1960-1969 were treated with unilateral temporal lobe resection of University Clinic of Neurosurgery, Rigshospitalet, Copenhagen. Neither before nor during the operation was any tumour or gross vascular malformation recognized in any of the patients. All patients suffered from psychomotor and/or focal seizures originating from the temporal lobe, and 55 of them also had grand mal. Their epilepsy was extremely severe and preoperatively all of them were socially handicapped due to their frequent and severe seizures and/or psychiatric disturbances. In all patients a unilateral or predominantly unilateral spike discharging temporal focus was demonstrated in routine EEG scalp recordings with sleep recordings or recordings with sphenoidal electrodes. The material comprises 43 males and 31 females. At the time of the operation the ages of the patients ranged from 4-54 years, with 14 of them being 15 years or younger. The median follow-up period was 5.1 years. In 60 of the patients the preoperative duration of epilepsy was more than 4 years. A retrospective follow-up investigation was undertaken in 1970-1971 covering various clinical, genetical, aetiological, social, psychological, neuropathological and electroencephalographic aspects. Some of these results have been already published (Inge Jensen 1975a,b,c, 1976a,b; Inge Jensen & Klinken 1976; Inge Jensen & Vaernet 1976). The overall effect of the operation on the seizures was found to be that 61”/0 of the patients were free from any seizures, 20 O/o had obtained a reduction in their seizure frequency by at least 75O/o, while the remaining 190/0 belong to the group “no change”, which comprises some reduction in seizure frequency, no change, and the four postoperative deaths (Table I). Table I also indicates that a unilateral temporal lobectomy favourably influences the psychiatric status, as one third of the patients were found to be without any psychiatric abnormality at the follow-up investigation as compared to one-eighth at the time of the operation, and further that another third showed marked psychiatric improvement.
829 Acta ophthal. 54, G
54
lnge Jensen and H . H. Seedorff Table 1. Effect of temporal lobe resection on seizures versus psychiatric status at follow-up.
Marked Some No No seizures reduction reduction change
Death
Total
Psychiatric status
Normal (pre- and postop.) (only postop.
4 11
2 4
0 0
0 1
0 0
6 8 O/o 16 22 O / o
Abnormal Markedly improved Improved
13 3
5 1
1 1
1 0
0 0
20 27 O / o 5 7 o/o
Unchanged/deteriorated (abnormal preop.) 11 (normal preop.) 3
3 0
2 1
2 1
4
22 30 O/o 3 7 o/o
5 7 O/o
4 5 O/o
4 5O/o 74 100°/o
Total
45 61 O/o
15 20°/o
0
As previously stated, this investigation is retrospective, but all patients, provided they could cooperate, were routinely examined immediately prior to the operation and one week postoperatively at the University Clinic of Neuroophthalmology, Rigshospitalet. It can further be noted that these 74 patients prior to the operation were examined by ophthalmologists o n 8 a total of at least 343 occasions during their hospital admissions, and on a further 245 occasions postoperatively, not including the examination at the follow-up investigation, which was also performed at the University Clinic of Neuroophthalmology, Rigshospitalet. The neuro-ophthalmological examinations generally included: 1) visual acuity, 2) eye position and eye movements, and pupillary conditions, 3) ophthalmoscopy, 4) visual field examination by campimetry (Bjerrum)
and these examinations were, if necessary, supplemented with others. At the follow-up investigation, 1970-7 1, all 70 surviving patients were examined clinically. Due to various irrelevant causes the ophthalmological examinations were not carried out in four patients (Nos. 16, 18, 46 and 62). The visual field has post830
Temporal Lobe Epilepsy and Neuro-ophthalmology operatively been recorded as normal in two of these (Nos. 18 and 62), in one (No. 16) a total homonymous hemianopia was recorded postoperatively, a defect which was still present and inconvenient to the patient; the last of these patients (No. 46), an autistic and imbecile boy could not cooperate but reacted normally to threats from various visual angles. Two of the four deceased patients were never examined postoperatively (Nos. 4 and 6), one (No. 35) had had normal postoperative examinations, while in the last patient (No. 32) a right-sided homonymous anopia affecting the upper quadrants had been described. The neuro-ophthalmologiczsl case material includes a total of 69 patients (Table 11).
Results of Neuro-Ophthalmological Examinations Visual acuity
At follow-up all patients were found to possess the same visual acuity as preoperatively.
Side of operation left N = 35
N o visual field defect Visual field defect present No examination
11 26 2
7 25 3
18 51
Extent of visual field defect affecting only upper quadrants partly including lower quadrants total hemianopia
15 6 5
23 1 1
38 7 6
Congruity of visual field defects Incongruity of visual field defects
15 11
14 92)
29 20
8
3
11
Macular involvement 1)
2)
Total N=74
right N=39
51)
Cases Nos. 4, 6, 32, 35 and 46. 2 patients have been excluded (Case No. 2 due to impaired cooperation, Case No. 5 due to choroidal tumour).
83 1 54"
Inge Jensen und H. H . Seedorff Visual field defects
Numerically and clinically the most important finding has been the postoperative visual field defect, which, as a homonymous hemianopia of a vaying extent, was present in 51 of the 69 patients examined. Preoperatively homonymous hernianopia was present in two patients (Nos. 29 and 76); this was completely unchanged at follow-up. While the occurrence of a postoperative hemianopia was independent of the side of the operation (Table 11), 7 1 O/O in right-sided temporal lobectomies and 73 O / O in left-sided, the extent of the anopia was significantly influenced by the side, as the lower quadrants were affected in 1 1 patients (i. e. 29 O/O) operated upon the right side as compared to two patients (i. e. 6 O/O) operated upon the left. In six patients the visual field defects were total hemianopias, only one of these was operated on the left (No. 16). The finding that the left-sided anopias are more extensive, is presumably due to the extent of the lobectomy, which was generally greatest on the right side (Inge Jensen & Vaernet 1976). When calculating the extent of the visual field defects it was found that the left-sided defects were approximately 300/0 larger than the right-sided. The difficulties in recognizing whether the observed visual field defects are congruent or non-congruent are mainly due to the fact that the horizontal borders can be difficult to define. It is generally acknowledged that the vertical border is always sharp. By contrast the horizontal border tends to be sloping, to a degree which varies according to the isopter used. The establishment of standards for congruity versus incongruity has been attempted by Van Buren & Baldwin (1958). According to these authors congruity is present when the difference between the extent of the visual field defects is less than 5' on repeated examinations. Observing these standards we found congruent visual Eield defects in 29 of the 49 patients with visual field defects at follow-up (i. e. 59 0/0), a number which corresponds with the 61 O / O observed by Walker & Walsh (1968) in their 18 patients. The question of congruity versus non-congruity of the visual field defects has also been investigated, as shown in Table 2, without any positive conclusions being reached. In accordance with Falconer & Wilson (1958), Van Buren & Baldwin (1958), Marino & Rasmussen (1968) and Walker & Walsh (1968) we observed that, with few exceptions, the visual field defects were consistently most marked on the ipsilateral side with the difference on average amounting to 5 O/O. The vision was unchanged postoperatively in all patients, but in eleven of them the visual field defect was found to be so centrally localized that involvement of the macula must have occurred. 832
Temporal Lobe Epilepsy and Neuro-ophthalmology
It is worth noting that a visual field defect affecting the upper quadrant only is in most cases unnoticed by the patient and not revealed until the neuro-ophthalmological examination, as already observed by Rsnne (1915). On the other hand, a visual field defect involving the lower quadrants will severely inconvenience the patient, and might for example prevent the patient from obtaining a driving license, as was the case in 13 of the patients.
Age at onset of epilepsy
Presence of grand ma1 %
01-
100 80 60
LO 20 n "
0-4 5-9 10-14 15-19 320 years Preoperative duration of epilepsi
No grand ma1
Grand ma!
Neuropathological lesion
% I""
80 60 LO
20 0 0 - L 5-9 10-11. 315
i]no
defect
0upper quadrants
years
1
2
3
L
upper and p a r t l y [3 lower quadrants
1
focal
2
total hemianopia
3
equivocal
L coagulation
disseminated
Fig. 1.
The presence and extent of postoperative visual field defects correlated to various clinical variables.
833
Inge Jensen and If. H. Seedorjf Table I I I . Visual field defects correlated to various variables (69 pafients available for examination). Visual field defect
1 Surgical results no seizures still seizures A g e at onset of epilepsy < 15 years 2 15 years Age at operation 5 15 years > 15 years Preoperative duration of epilepsy < 10 years 2 10 years Grand ma1 present absent
present N=51
75O/o 72 O / o
11 7
25 O / o 28 O/o
36 15
80 O / o 63 OIo
9 9
20'Olo 38 O / o
7
54 010 79 '10
6 12
46O/o 21 010
35
62 OIo 81 010
10 8
38 O/o 19 o/o
39 12
78 OIo 63 O / o
11 7
22 010 37 010
8 43
89 010 72 OIo
1 17
11 010 28O/o
23 7 9 12
85 O / o 58 OIo 53 010 92 O/o
4 8 1
15 O / o 42 O/o 47 010 8 010
8 100 010 43 70 O/o
0 18
30 O/o
16
Strabismus present absent
absent N=18
33 18
44
Peroperative coniplications present absent Neuropathology disseminated focal questionably abnormal previous coagulation
I
5
The presence of a postoperative visual field defect has been correlated to various clinical aspects, as shown in Fig. 1 and Table 111. The presence or absence of a visual field defect does not in any way prognostically influence the surgical outcome regarding relief from seizures, but, with an increase in 834
Temporal Lobe Epilepsy and Neuro-ophthalmology
the extent of the visual field defect, an increase in the number of seizurefree patients is observed: No visual field defect - 61 O/O seizure-free patients, a visual field defect involving the upper quadrants alone - 62 O/O seizure-free patients, and a visual field defect also involving the lower quadrants - 69 O/o seizure-free patients. This trend is, however, not statistically significant. Apparently, it would seem that preoperative presence of grand ma1 seizures, young age at onset of epilepsy, a long preoperative duration of epilepsy and consequently higher age at operation, peroperative difficulties with the haemostasis, and preoperative strabismus promote the occurrence of a postoperative visual field defect, but these trends are not statistically significant. With regard to the neuropathological findings it is observed that the more diffuse and disseminated the lesion, the higher the incidence of visual field defects. Strabismus
A total of eight patients (i. e. 10.8 O/O) had strabismus, all of whom were submitted to operative correction. This incidence was considerably highly than expected from the incidence in normal school children of 4.50/0 (Anna D. Frandsen 1960), but the difference is not statistically significant. She also
Table IV. The presence of strabismus correlated to various clinical variables. Strabismus present
absent
N=S
N=66
Surgical results no seizures marked reduction no change
7 1 0
38 14
Predisposition to neurological disease present absent
2 6
34
Perinatal complication present absent
3 5
25
835
14
32
41
Inge Jensen and H. H. Seedorff
found an increasing incidence of strabismus with decreasing intellectual levels. Our findings are in full accordance with Millar (1965), who, in his material of 401 patients with epilepsy, observed an incidence of 10 O/O. He concluded that the tendency to squint was more closely correlated to birth injuries than to the severity of the epilepsy. This conclusion could not be substantiated by the pesent investigation. Apparently the presence of strabismus favourably influences the surgical prognosis regarding relief from seizures, but this trend is definitely not statistically significant (Table IV).
Discussion Wilbrand (1890) was one of the first to describe the architecture of the visual pathways, and with regard to their course in the temporal lobe he stated that the visual pathways after their departure from the lateral geniculate bodies divide into three bundles, a superior horizontal bundle comprising nerve fibres from the homonymous superior half of the retina, an inferior one comprising nerve fibres from the inferior part of the homonymous half of the retina, and lastly an intermediary bundle, which is displaced somewhat medially and which contains nerve fibres from the corresponding homonymous macula areas. Meyer (1907) was of the opinion that the inferior (ventral) nerve fibres, after the departure from the lateral geniculate bodies, bend forward and pass round and over the temporal horn of the lateral ventricle, “Meyer’s loop”, before they continue backwards down into the inferior part of the temporal lobe and into the lateral wall of the lateral ventricle to join the two other bundles, mentioned previously, on their common path to the occipital lobe. Ranne (1915, 1919, 1938) in his concept of the visual pathways in the temporal lobe was in full agreement with the authors mentioned above. He based his observations on clinical case histories, and one of his conclusions was that a visual field defect in upper homonymous quadrants must be a symptom of a lesion in the temporal lobe affecting Meyer’s loop. As one of the first Ranne (1915) discussed the question of congruity versus non-congruity in lesions in the temporal lobes. Rsnne (1915) and Harrington (1939), among others, advocated the concept that the course of the nerve fibres in the visual pathways in the temporal lobe is subject to extremely marked individual variations. Ranne (1915), Traquair (1922, 1949) and Falconer & Wilson (1958), were of the opinion that lesions in the temporal lobe generally result in congruity of the visual field defects, and that the demarcation lines will as a rule be sharp. In contrast Gushing 836
Temporal Lobe Epilepsy and Neuro-ophthalmology
j1922), based on his own operative experience, was of the opinion that incongruity is predominant following lesions in the temporal lobe; due to the anatomical fact that the homonymous nerve fibres had not yet joined each cther. Furthermore, he was of the opinion that the horizontal inferior border of the visual field defect was always sloping. As previously mentioned, the study of the visual field defects after welldefined temporal lobe resections in drug-resistant temporal lobe epilepsy has presented the best information to date concerning the architecture of the visual pathways. Investigations by Van Buren & Baldwin (1958) and Walker & Walsh (1968) supported the concept that operative lesions in the temporal lobe generally result in incongruity of the visual field defects. Walker & Walsh (1968) asserted that this point of view is supported by the results from studies on the retrograde degeneration of nerve cells in the lateral geniculate corpora following lesions in the optic radiation and the striate area, respectively. These studies would, according to Walker & Walsh (1968), also account for the fact that the vertical demarcation of the visual field defect always is sharp, while the horizontal tend to be sloping. R0nne (1915) was very interested in the difficulties in determining the horizontal border in visual field defects. This difficulty is probably the main reason for the as yet unresolved divergences concerning the concept of congruity. It is generally agreed that the vertical border is always sharp, independent of the isopters used, while on the other hand there can be considerable variations in the horizontal border. This horizontal borderline zone might, depending upon the isopters, assume a fan-like appearance, which, in incongruity, might appear as a relative defect on one side, and as an absolute defect on the other for the same object. The question of congruity versus incongruity is also a question of accepting a rigid and more and less arbitrary standard of 5' with regard to the horizontal borderline. Like Walker & Walsh (1968), we are disinclined to accept a ruling that visual field defects should be considered congruent when a difference of 5' is accepted. W e therefore agree with Harrington (1939) and M7alsh & Hoyt (1969), who conclude that the more posterior the localization of the lesion, the more the visual field defects approach congruity, becoming definitely congruent in lesions close to the striate area. The reason for the incongruity, or at any rate questionable congruity, in lesions in the temporal lobe as compared to a definite congruity in lesions in the occipital lobe, is that the corresponding nerve fibres from the homonymous retinae anatomically complete their fusion very close to the striate area. The presence or the extent of the visual field defects is largely dependent upon the extent of the operative lesion, as demonstrated by Harrington (1961), a37
Inge Jensen and H . H . Seedorff
who observed that resections performed 8 cm or more from the tip of the temporal pole very frequently resulted in total hemianopia. This complication might also be due to disturbances of the blood supply to the visual pathways. Following the operation the visual acuity is very seldom disturbed, even in the very few cases in the present material in which there was a suspicion of macular splitting. This is probably due to the fact that the homonymous fibres from the macula, in the temporal lobe, are localized medially in the optic radiation and thus close to important cerebral areas which the neurosurgeon attempts to spare during the operation, for example the posterior parts of the superior temporal gyrus. The importance of the extent of the lobectomy has also been demonstrated in the present material where the number of visual field defects including the lower quadrants is significantly higher in the right-sided lobectomies than in the left-sided (Table 11),2 and 11 per cent respectively, which corresponds well with the fact that right-sided lobectomies are generally larger than leftsided. Apart from this finding, we, like Falconer & Wilson (1958), have not found any significant correlations between the extent of the lobectomy and the degree of the anopia. As mentioned previously, 33 O/O of the patients had retained their normal visual fields following resections varying in extent from 5.5 to 7 cm. Also in accordance with these authors we observed that an opening of the tip of the lateral ventricle did not necessarily result in a postoperative visual field defect. The individual variations in the course of Meyer’s loop, as suggested by Renne (1915), can explain this observation.
Conclusion With regard to the architecture of the visual pathways in the temporal lobe, the present investigation is in full agreement with surveys previously published. Primarily the purpose was not to attempt to supply new information about the anatomy of the visual pathways, but rather, based on clinical observations, to correlate the importance of anterior temporal lobectomy in the treatment of drug-resistant temporal lobe epilepsy with the ophthalmological complications which might result from this operation, and above all to the homonymous visual field defects. This topic is a typical borderline subject between the two related specialities, neurology and ophthalmology. From the neurological point of view a unilateral temporaI lobectomy has proved to be successful in relieving patients with drug-resistant temporal lobe epilepsy of their seizures and has in many cases also made a social rehabilitation possible. From the ophthalmolo838
Temporal Lobe Epilepsy and Neuro-ophthalmology
gical point of view a visual field defect was found to be a postoperative complication in two-thirds of the patients, but in the majority of these cases it was of only minor importance (viz. the visual field defects affecting the upper quadrants only). Based on the knowledge accumulated in literature during the last 60 to 70 years, and on our own experience, it must be emphasized that very marked individual variations are observed in the course of the visual pathways in the temporal lobe, especially regarding the Meyer’s loop, even though there is correlation between the extent of the temporal lobe resection and the postoperative presence of a visual field defect. Accordingly it is not possible to predict whether a visual field defect will occur or not, not can the extent of any postoperative defect be predicted. If the relatively few cases (13 of 74) with visual field defects including the lower quadrants are set against the satisfactory results regarding relief from seizures and social rehabilition, most importance must be attached to these results, provided that the visual acuity remains unaffected. The present investigation also supports the opinion that this operation should preferably be carried out in childhood, adolescence, or early adulthood, and should definitely be undertaken as soon as the epilepsy has proved to be resistant to medication.
References Bailey P. (1954) Betrachtungen iiber die chirurgische Behandlung der psychomotorischen Epilepsie. Zbl. Neurochir. 14, 195-206. Brown I. A,, French L. A., Ogle W. S. & Johnson S. (1956) Temporal lobe epilepsy; its clinical manifestations and surgical treatment. Medicine 35, 425459. Cushing H. (1922) The field defects produced by temporal lobe lesions. Bruin 44, 431-442. Davis E. (1963) A review of the features and treatment of temporal lobe epilepsy; with special reference to surgery. Proc. Aust. Ass. Neurol. I , 27-30. Edmund J. (1954) Visual disturbances associated with gliomas of the temporal and occipital lobes. Acta psychiat. scand. 29, 291-310. Falconer M. A. (1965) The surgical treatment of temporal lobe epilepsy. Nezsrochirurgia (Stuttg.) 8, 161-172. Falconer M. A., Hill D., Meyer A., Mitchell W. & Pond D. A. (1955) Treatment of temporal lobe epilepsy by temporal lobectomy. Lancet I, 827-835. Falconer M. A. & Serafetinides E. A. (1963) A follow-up study of surgery in temporal lobe epilepsy. /. Neurol. Neurosurg. Psychiat. 26, 154-165. Falconer M. A. & Wilson J. L. (1958) Visual field changes following anterior temporal lobectomy. Brain 81, 1-14. Frandsen Anna D. (1960) Occurrence of squint. Copenhagen 1960. Thesis, 151.
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Inge /ensen. and H . H. Seedorff Green J. R. (1967) Temporal lobectomy; with special reference to selection of epileptic patients. J . Neurosurg. 26, 584-593. Green J. R. & Scheetz D. G. (1964) Surgery of epileptogenic lesions of temporal lobe. Arch. Neurol. (Chicago) 10, 135-148. Guillaume J. & Mazard G. (1956) Indication et rksultats du traitement chirurgical des epilepsies temporales. Sem. H6p. Paris 32/2, 2013-2018. Harrington D. 0. (1939) Localizing value of incongruity in defects of visual fields. Arch. Ophthal. (Chicago) 21, 453-467. Harrington D. 0. (1961) The character of visual field defects in temporal and occipital lobe lesions, localizing value of congruity and incongruity in incomplete homonymous hemianopsia. Trans.amer. ophthal. SOC.59, 333-345. Harrington D. 0. (1971) The Visual Fields, p. 304-308. C. V. Mosby, St. Louis. Hullay J. (1965) Surgical treatment of temporal lobe epilepsy. Acta med. Acad. Sci. hung. 7, 295-320. Jensen Inge (1975a) Temporal lobe surgery around the world. Results, complications, and mortality. Acta neurol. scand. 52, 354-373. Jensen Inge (197513) Temporal lobe epilepsy. Late mortality in patients treated with unilateral temporal lobe resection. Acta neurol. scand. 52, 374-380. Jensen Inge (1975~)Genetic factors in temporal lobe epilepsy. Acta neurol. scand. 52, 381-394. Jensen Inge (1976a) Temporal lobe epilepsy. Etiological factors and surgical results. Acta neurol. scand. 53, 103-118. Jensen Inge (1976b) Temporal lobe epilepsy. Social conditions and rehabilitation after surgery. Acta neurol. scand. 54, 22-44. Jensen Inge & Klinken L. (1976) Temporal lobe epilepsy and neuropathology. Acta neurol. scand. 54, in press. Jensen Inge & Vaernet K. (1976) Temporal lobe epilepsy. Follow-up investigation of 74 temporal lobe resected patients. Acta neurochir. ( W i e n ) , in press. Marino R. & Rasmussen T. (1968) Visual field changes after temporal lobectomy in man. Neurology (Minneap.) 18, 825-835. Meyer A. (1907) The connections of the occipital lobes and the present status of the cerebral visual affections Tians. Ass. Amer. Phycns 22, 7-16. Millar J. H. D. (1965) Epilepsy and strabismus. Epilepsia 6, 43-46. Oldberg S. (1937) Versuch zur Erklarung der Quadrantanopsie bei Schlafenlappentumor. Acta rned. scand. 93, 330-345. Rsnne H. (1915) Ueber die Inkongruens und Asymmetrie in dem homonymen hemianopischen Gesichtsfeld. Klin. Mbl. Augenheilk. 54, 309-325. Rsnne H. (1919) Ueber die Quadranthemianopsie und die Lage der Maculafacern in dem occipitalen Sehbahn. Klin. Mbl. Augenheilk. 63, 358-365. Rsnne H. (1938) The focal diagnostic of the visual pathways. Acta ophthal. (Kbh.) 16, 446-456. Traquair H. M. (1922) The course of the geniculocalcarine visual pathways in relation to the temporal lobe. Brit. /. Ophthal. 6, 251-261. Traquair H. M. (1949) A n Introduction to Clinical Perimetry, 6th ed. C. V. Mosby, St. Louis, 212-245. Van Buren J. M. & Baldwin M. (1958) The architecture of the optic radiation in the temporal lobe of man. Brain 81, 15-40.
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Temporal Lobe Epilepsy and Neuro-ophthalmology Van Buren J. M., Ajmone-Marsan C., Mutsuga N. & Sadowsky D. (1975) Surgery of temporal lobe epilepsy. In: Purpura D. P., Penry J. K. and Walter R. D., Eds. Advances in Neurology, Vol. 8, pp. 155-196. Raven Press, New York. Walker A. E. & Walsh F. B. (1968) Neuro-ophthalmological Symposium, p. 249-268.' C . V. Mosby, St. Louis. Walsh F. B. & Hoyt W. F. (1969) Clinical Neuro-ophthalmology, 3rd ed., 2185-2214. Williams & Wilkins Comp., Baltimore. Wilbrand H. (1890) Die Hemianopsiegeschichtfeldformen.Wiesbaden.
Author's address: Inge Jensen, M. D., Department of Neuromed., Glostrup Hospital, DK-2600 Glostrup, Denmark.
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