:Acta Acta Neurochir (Wien) (1991) 111:128-131 . N&rochlrurgica 9 Springer-Verlag 1991 Printed in Austria Traumatic Interhemispheric Subdural Haematomas R. Vaz, F. Duartc, J. Oliveira, A. Cerejo, and C. Cruz Department of Neurology and Neurosurgery, Hospital S. Jog.o, Oporto, Portugal Summary Clinical Material According to reports in the literature traumatic interhemispheric subdurai haematomas (I.S.H.) are supposed to present acutely or subacutely with contralateral monoparesis of a lower extremity or hemiparesis or in bilateral haematomas even with paraparesis, and to need early operative evacuation. In our series of 5 cases none of them followed this "classical" clinical picture, and three of them recovered without operation. We conclude that the indication for operative evacuation depends on the clinical course and that in patients with spontaneously improving symptomatology non-surgical management under close supervision may be the better solution. Also the C.T. finding of open convexity cisterns may be possible indication for conservative management. Patient 1 Keywords: Subdural haematoma; interhemispheric; head injury; computed tomography. Introduction Interhemispheric subdural haematomas (I.S.H.) p r o b a b l y r e p r e s e n t o n e o f the r a r e s t f o r m s o f p o s t - A 25-year-old man was admitted to our hospital approximately one hour after a motor vehicle accident. No details regarding the events of the accident were available. Upon admission he was in deep coma without response to painful stimulation, had medium sized and unreactive pupils and ataxic respiration. C.T. scan revealed a I.S.H. (Fig. 1). He died a few minutes later. Autopsy confirmed the presence of an interhemispheric subdural haematoma; additionally bilateral cerebral and brainstem contusions were found. Patient 2 A 16-year-old girl was hit by a car. Coma with bilateral decerebrate posturing and absence of the pupillary responses to light were present on admission. C.T. scan revealed a large I.S.H. (Fig. 2). An emergency parieto-occipital craniotomy was performed: after opening the dura the interhemispheric haematoma was removed with irrigation and suction and a bridging vein between the sagittal sinus and the cerebral cortex was found lacerated. Post-operatively she gradually improved and was discharged 35 days after surgery with serious disorientation; six months later she was able to go back to school although some psychological deficit still persisted. t r a u m a t i c i n t r a c r a n i a l h a e m o r r h a g e s . T h e y w e r e first d e s c r i b e d at a u t o p s y b y A i r i n g a n d E v a n s ~ in 1940 a n d first r e c o g n i z e d d u r i n g life by J a c o b s e n 8 in 1955: since t h e n a t o t a l o f 101 cases o f I . S . H . h a v e b e e n r e p o r t e d , m o s t o f t h e m as single c a s e r e p o r t s . A l t h o u g h m a n y o f the cases in the l i t e r a t u r e w e r e d e s c r i b e d b e f o r e the d a y s o f c o m p u t e r i z e d t o m o g r a p h y a n d M R scans, i m m e d i a t e s u r g e r y w i t h e v a c u a t i o n o f I . S . H . w a s u s u a l l y p r o p o s e d . N e v e r t h e l e s s t h r e e o f our patients recovered without operation. The problem of t h e i n d i c a t i o n f o r s u r g e r y o f t h e s e lesions still r e m a i n s , a n d so we t h i n k t h e C . T . - f i n d i n g s o f a I . S . H . a l o n e is n o t e v i d e n c e o f n e e d for a n o p e r a t i o n , a n d t h a t c o n s e r v a t i v e t r e a t m e n t m a y be i n d i c a t e d in cases w i t h o u t m a j o r n e u r o l o g i c a l deficit unless n e u r o l o g i c a l deterio r a t i o n occurs. Fig. I. Non-enhanced C.T. scan showing the acute left frontal interhemispheric subdural haematoma R. Vaz et al.: Traumatic Interhemispheric Subdural Haematomas Fig. 2. Computerised tomogram revealing a mass with the density of clotted blood lying along the falx 129 Fig. 4. C.T. scan shows characteristic findings of right interhemispheric subdural haematoma, with straight midline and convex lateral borders Fig. 3. C.T. scan without contrast enhancement disclosing left interhemispheric lesion of increased density consistent with clotted blood Patient 3 A 44-year-old man sustained head trauma in a car accident. On admission he was drowsy, had normal fundi and pupils and a right hemiparesis, severest in the face and arm. C.T. scan showed an area of increased density to the left of midline in the parieto-occipital region (Fig. 3). Most of the sulci of the surface of the hemispheres seemed to be open. We decided upon conservative treatment and in the next two days the patient made a good recovery, being fully conscious but still hemiparetic. By two weeks the haematoma had completely resolved and the patient was discharged with only moderate hemiparesis, gradually improving. Six months later there was no neuroiogical or psychological deficit. Patient 4 This 62-year-old diabetic man fell at home and struck his occiput. He was brought to a local hospital, where X-ray of the skull showed no fracture, and was sent home. However over the next 24 hours he complained of intermitent headache, which persisted for a week, and was then transfered to our neurosurgical unit. Neurological examination on admission was entirely normal. C.T. scan revealed an I.S.H. (Fig. 4), but the outer CSF-spaces were wide open. No surgery was performed. Over the next few days his headache disappeared. Fig. 5. Computerised tomogram exhibiting an interhemispheric subdural haematoma lying along the left side of the falx in the parietooccipital region A new C.T. two weeks after injury showed complete resolution of the haematoma, and the patient was discharged without any neurological deficit. Patient 5 A 69-year-old man fractured his left femur and struck his head in a fall. Upon admission to the hospital he was alert but confused, yet free from other abnormal neurological signs. C.T. scan showed an I.S.H. (Fig. 5). Some of the sulci of the cerebral convexity were still open. The neurological status quickly improved during the next 24 hours without surgery. The patient made a complete recovery and was asymptomatic at discharge three weeks later. Discussion Interhemispheric subdural haematomas (I.S.H.) are usually caused by blunt direct head injury 9 or by indirect lesions in young children abused by violent 130 shaking 16. Major trauma has been implicated in only a few cases, and more frequently the injury is minor, with or without a brief period of unconsciousness 13. Other aetiologies include abnormalities of coagulationl2, i5 and subdural bleeding due to aneurysms 3, 6 The mechanism involved in the development of a traumatic interhemispheric h a e m a t o m a is the bleeding from a torn bridging vein between the cerebral cortex and the superior sagittal sinus s. As illustrated by Glista e t al. 5 the firm adherence of the arachnoidal trabeculations between the brain and parasagittal dura usually confines the h a e m a t o m a to the interhemispherical region. Therefore I.S.H. are usually unilateral, but they can sometimes become bilateral or extend to the cerebral convexity 2' 15 The classical clinical presentation of this disorder, because of the peculiar location to the parasagittal region, is contralateral monoparesis of the leg, paraparesis or hemiparesis with the leg being weaker than the arm, noted in most of previously reported cases 5' 7, 9, 10, 12, 13 Nevertheless we had not found these signs in any of our patients. Another interesting finding is that none of our cases had the subacute or chronic course frequently reported, with the onset of headaches, vomiting, and focal neurological signs appearing hours to days after the injury 5' 7. One of them died shortly after admission as a consequence of bilateral cerebral and brainstem contusions. Patient 2 was operated as an emergency because she had bilateral decerebrate posturing and absence of pupillary light responses. The others steadly improved. So we think that although the clinical picture and course, as described in the literature, m a y be c o m m o n there is no pathognomonically characteristic presenting m o d e of I.S.H.. C.T. scan provides an immediate diagnosis defining the exact extent of the h a e m a t o m a and its possible association with other lesions 4' 5, 9, 10, 13, 15, 16. As reported by H o 7, I.S.H. usually have a flat broad base attached to the falx and a convex lateral border. It is differentiated from subarachnoid haemorrhage 12 and intracerebral h a e m a t o m a 7 by its size and shape, and from interhemispheric empyema 14 by its density 13. C.T. scan images of I.S.H. can also prevent with different densities and with bilateral convex border in case of Nlateral haematomas (patient 2). Characteristically we found in the three patients managed without sUrgery open convexity and basal cisterns in the initial C.T.: this aspcct (revealing that the intracranial pressure is not significantly elevated), besides clinical improve- R. Vaz etal.: Traumatic Interhemispheric Subdural Haematomas ment, m a y be an indication that in such cases immediate operative evacuation of the h a e m a t o m a is not necessary and the further clinical course may be observed. Also all of them had total re-absorption of the h a e m a t o m a as shown by the C.T. done two weeks after admission. The experience of m a n y authors 2' 5, 9, 12, 15 suggested that immediate craniotomy with total evacuation of I.S.H. is the only safe and acceptable method of treatment, and that this condition may have a grave prognosis in spite of emergency surgical treatment: they emphasize the possible lack of specific signs heralding the presence of the haematoma, and the possibility of quickly progressive deterioration of consciousness. With regard to our experiences we cannot accept this as a general rule, and as Ogsbury ~~ and Fruin 4, we believe that some of these haematomas may resolve spontaneously, and that in a relatively asymptomatic patient, under close supervision, operation may be postponed in the first instance. There are very few reported cases 4' 10, 15, 17 of I.S.H. in which the initial symptoms were not severe and whose neurological status stabilized without surgery: nevertheless we feel that although large haematomas might be the indication for surgery, I.S.H. does not necessarily imply surgical treatment and that conservative treatment may be beneficial unless acute or progressive neurological deterioration occurs. Craniotomy is the preferable technique for adequate exposure 5, 9 and since the h a e m a t o m a does not present upon the surface of the hemisphere, this must be retracted in order to achieve a satisfactory removal without injuring draining veins 5' 13 References 1. Aring CD, Evans JP (1940) Aberrant location of subdural haematoma. Arch Neurol Psychiat (Chicago) 44:1296-1306 2. Clein LJ, Bolton CF (1969) Interhemispheric subdural haematoma: a case report. J Neurol Neurosurg Psychiatry 32: 389392 3. 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Zimmerman RD, Russell EJ, Yurberg E (1982) Falx and interhemispheric fissure on axial CT: II Recognition and differentiation of interhemispheric subarachnoid and subdural hemorrhage. AJNR 3:635-642 Correspondence and Reprints: R. Vaz, M.D., Department of Neurology and Neurosurgery, Hospital de S. Jo~o, 4200 Oporto, Portugal.