J Neurosurg 60:1300-1302,1984

Interhemispheric subdura! hematoma
Case report
ALAN H. FRUIN, M.D., G~EGORV L. JUHL,B.S., AND CHARLES TAYLON,M . D .

Division of Neurological Surgery, Department of Surgery, Creighton University School of Medicine,
Omaha, Nebraska
u- A case of interhemispheric subdural hematoma (ISH) is presented and discussed. This disorder is a rare
form of intracranial hemorrhage, which classically presents as an isolated paresis of one leg or a hemiparesis
worse in the leg than the arm. The majority of cases are due to occipital trauma because of the anatomy of
the bridging veins. Chronic interhemispheric hematomas are rare since the natural history of these lesions is
to spread out over the cerebral convexity. Conservative treatment for ISH may be beneficial unless neurological
deterioration necessitates early operative intervention.
KEY WOADS
9 brain injury
9 head injury
interhemispheric subdural hematoma

I

NTERHEMISPnERIC subdural hematoma (ISH) is a
rare form of posttraumatic intracranial hemorrhage. Only 13 such cases have previously been
reported in the literature, l'2"4-f&m't3'14,~6'17Neurological
deterioration has required early operative intervention
in these cases. We report a case of an acute traumatic
ISH managed nonoperatively. The literature is reviewed
and the unique aspects of this entity are presented and
discussed.
Case Report

This 59-year-old man fell at work and struck his
occiput. There was no history of loss of consciousness.
The patient was seen at a clinic where a scalp laceration
was sutured. Skull roentgenograms and neurological
examination at that time were normal. Over the next
24 hours he experienced continuous headaches and two
episodes of vomiting. Eighteen hours after the fall he
began to develop numbness and weakness in his left
leg. He was taken to the emergency room 24 hours after
the injury, and a marked left lower-extremity monoparesis was noted. Computerized tomography (CT) of
the head revealed a right ISH (Fig. 1 left). Since the
patient was awake and alert, it was decided to initially
treat him medically. An intracranial pressure (ICP)
monitor was inserted, and ICP was recorded as 20 m m
Hg. Intermittent mannitol was given to maintain an
[CP of 15 m m Hg or less. Despite adequate control of
1300

9 subdural hematoma

9

the patient's ICP, mild weakness developed in his left
arm, and the left leg became totally paretic. The 1CP
eventually felt to below 10 m m Hg, and mannitol was
discontinued on the 6th day after injury. The ICP
monitor was removed 1 week later. After the ICP
returned to a normal level, there was gradual improvement in the patient's left-sided weakness, which completely cleared by 6 weeks after the fall. During this
period, a CT scan showed a gradual shift of the ISH to
the right cerebral convexity 4 weeks after trauma (Fig.
1 center). By 10 weeks, the hematoma had completely
resolved (Fig. 1 right).
Discussion

Interhemispheric subdural h e m a t o m a is a rare clinical entity first described by Aring and Evans in 1940. ~
The classical presentation of this disorder is a contralateral monoparesis of the leg or a hemiparesis in which
the leg is weaker than the arm. This symptom complex
has been called the "falx syndrome,'" 1,13and was noted
to be present in 10 of the 13 previously reported
cases. 1'2'4-6'9'10'13'14'16,17The only other symptoms consistently associated with this disorder include headache,
vomiting, and seizures (Table 1). A history of loss of
consciousness or evidence of skull fracture is not commonly associated with ISH (Table 1).
The site of injury, however, does appear to be significant. In eight of the cases reported to date, the site

J. Neurosurg. / Volume 60/June, 1984

Interhernispheric subdural hematoma

FIG. 1. Computerized tomography scans showing the course of the interhemispheric subdural hematoma. Left: Scan at 24 hours post-injury showing the acute hematoma. Center: Scan at 4 weeks post-injury
showing shift of the hematoma to the convexity as it became chronic. Right: Scan at 10 weeks post-injury
showing complete resolution of the hematoma.

o f the t r a u m a was given: in six o f these the t r a u m a was
occipital (Table 1). It has also been shown that the cause
o f ISH is the tearing o f a bridging vein between the
cerebral cortex a n d the superior sagittal sinus. 6 The
a n a t o m y o f these veins is such that they course antero m e d i a l l y before entering the sinus. 7 A sharp blow to
the occiput in the sagittal plane would cause posterior
m o v e m e n t o f the cerebral hemisphere relative to the
fixed sinus. Such a m o v e m e n t would m a x i m a l l y stretch
the veins, m a k i n g t h e m vulnerable to tearing.
A l t h o u g h chronic subdural h e m a t o m a s m a k e up 25 %
to 50% o f all subdural h e m a t o m a s , 3'~2'~5 a m o n g the 14
cases o f ISH d o c u m e n t e d to date only one m a y have
been chronic. 16The paucity o f reported cases o f chronic
ISH m a y be explained by the t e n d e n c y o f the acute
ISH to migrate over the convexity as it liquefies. This
p h e n o m e n o n was present in our case, and also in a case

reported by Ogsbury, et al. ~3 These are the only two
reported cases o f ISH not treated surgically during the
acute phase. In a large series o f chronic subdural hem a t o m a s , Hirakawa, et al., 8 found no cases o f chronic
ISH. However, they noted that occipital t r a u m a was
the etiology in 30% o f their cases. The possibility thus
arises that some chronic convexity subdural h e m a t o m a s
m a y originate as ISH.
Finally, with the p r o p o s e d progression o f this disorder in mind, a s o m e w h a t b r o a d e r o u t l o o k in the m a n a g e m e n t o f ISH than has been a d v o c a t e d previously
m a y be in order. P r o m p t surgical intervention has been
r e c o m m e n d e d as the only safe and acceptable m e t h o d
o f treatment, 4'6'~~ b u t this m a y not necessarily be true.
The m a j o r i t y o f cases reported to date involved patients
whose neurological deterioration was so acute a n d progressive that i m m e d i a t e surgical intervention was indi-

TABLE 1
Clinical summary of 14 cases of interhemispheric subdural hematoma

Case
No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14

Site of
Trauma

Authors, Year
Aring & Evans, 1940
Gannon, 1961
Wollschlaeger & Wollschlaeger, 1 9 6 4
Clein & Bolton, 1969
Sibayan, et al., 1970
Ho, et al., 1977
Ogsbury,et al., 1978
Glista, el al., 1978
Kasdon, et al., 1979
Fearnside, et al., 1979
Pozzati, et al., 1982
Fruin, et al., 1984

J. Neurosurg. / V o l u m e 6 0 / J u n e ,

1984

occipital
not given
occipital
parietal
not given
not given
not given
occipital
occipital
occipital
frontal
not given
not given
occipital

Skull
Fracture
no
yes
no
no
unknown
unknown
unknown
no
unknown
unknown
no
yes
no
no

Loss of ConFalx
sciousness Syndrome
yes
yes
yes
yes
no
no
no
no
no
no
no
no
no
no

yes
yes
yes
yes
yes
yes
no
yes
yes
yes
yes
no
no
yes

Other
Symptoms
seizures
---headache
-headache, seizures
headache,seizures, vomiting
seizures
headache, vomiting
-headache, vomiting
-headache, vomiting
1301

A. H. Fruin, G. L. Juhl and C. Taylon
cated. Evacuating these hematornas at craniotomy without causing further trauma to the attached bridging
veins can be difficult. It would be much easier to treat
the hematoma after it has shifted out over the convexity.
With this communication, there are now two reported
cases of ISH in which the initial symptoms were less
severe, and the patient's neurological status stabilized
with conservative treatment.13 With this mode of treatment, the patient's ICP and neurological status should
be closely monitored, and the patient should proceed
to craniotomy only if neurological deterioration indicates surgical intervention.

References
1. Aring CD, Evans JP: Aberrant location of subdural hematoma. Arch Neurol Psychiatry 44:1296-1306, 1940
2. Clein LJ, Bolton CF: Interhemispheric subdural haematoma: a case report. J Neurol Neurosurg Psychiatry 32:
389-392, 1969
3. Echlin FA, Sordillo SVR, Garvey TQ Jr: Acute, subacute,
and chronic subdural hematoma. JAMA 161:1345-1350,
1956
4. Fearnside MR, Hall K, Sengupta RP: Interhemispheric
subdural haematoma following head injury. Aust NZ J
Surg 49:678-680, 1979
5. Gannon WE: Interhemispheric subdural hematoma. Case
report. J Neurosurg 18:829-830, 1961
6. Glista GG, Reichman OH, Brumlik J, et al: Interhemispheric subdural hematoma. Surg Neurol 10:119-122,
1978
7. Goss CM: Gray's Anatomy of the Human Body, ed 29.
Philadelphia : Lea & Febiger, 1973, pp 687-688

1302

8. Hirakawa K, Hashizume K, Fuchinoue T, et al: Statistical
analysis of chronic subdural hematoma in 309 adult cases.
Neurol Med Chit 12:71-83, 1972
9. Ho SU, Spehlmann R, Ho HT: CT scan in interhemispheric subdural hematoma. Clinical and pathological
correlation. Neurology 27:1097-1098, 1977.
10. Kasdon DL, Magruder MR, Stevens EA, et al: Bilateral
interhemispheric subdural hematomas. Neurosurgery 5:
57-59, 1979
11. List CF: Interhemispheral subdural suppuration. J Neurosurg 7:313-324, 1950
12. McKissock W, Richardson A, Bloom WH: Subdural haematoma. A review of 389 cases. Lancet 1:1365-1369,
1960
13. Ogsbury JS, Schneck SA, Lehman RAW: Aspects of
interhemispheric subdural haematoma, including the falx
syndrome. J Neurol Neurosurg Psychiatry 41:72-75,
1978
14. Pozzati E, Gaist G, Vinci A, et al: Traumatic interhemispheric subdural hematomas. J Trauma 22:241-243,
1982
15. Rosenbluth PR, Arias B, Quartetti EV, et al: Current
management of subdural hematoma. Analysis of I00
consecutive cases. ,IAMA 179:759-762, 1962
16. Sibayan RQ, Gurdjian ES, Thomas LM: Interhemispheric
chronic subdural hematoma. Report of a case. Neurology
20:1215-1218, 1970
17. Wollschlaeger PB, Wollschlaeger G: The interhemispheric
subdural or falx hematoma. AJR 92:1252-1254, 1964
Manuscript received October 27, 1983.
Address reprint requests to: Alan H. Fruin, M.D., Division
of Neurological Surgery, Creighton University School of Medicine, 601 North 30th Street, Omaha, Nebraska 68131.

J. Neurosurg. / Volume 60 / June. 1984