Rare occurrence of a huge traumatic extradural haematoma in a patient with an ipsilateral sylvian arachnoid cyst

Abstract

A man, a teenage victim of an assault to the head, presented to the emergency department, in Baghdad, with a Glasgow Coma Score of 4/15 (E1 M2 V1) and total right-sided paralysis. CT of the brain revealed a large-left sided frontotemporoparietal extradural haematoma with the presence of an ipsilateral sylvian arachnoid cyst deep to the haematoma. Urgent surgical evacuation of the haematoma was performed, leaving the arachnoid cyst intact. The patient improved and gained full consciousness within 4 days.

Three years after the initial trauma, the patient has remained well. This case required a thorough discussion of the surgical options, in particular whether to intervene with the associated cyst, and whether any intervention with the cyst should be performed in the same or future operations. This dilemma forms the basis of the discussion in the following report.

Background

Arachnoid cysts (ACs) are congenital intracranial lesions that have profound clinical implications when associated with haemorrhagic complications. Subdural haemorrhage (SDH) has been extensively reported in conjunction with predisposing AC and the likely aetiology has been documented,^{1 2} however, the occurrence of an extradural haematoma (EDH) is rare.³ This presentation poses a surgical challenge, particularly if the space-occupying lesions are on the same side of the brain. A literature review on the subject revealed only seven reported cases of EDHs associated with the presence of AC.^{1 3–7} The management options are varied and depend on the unique patient presentation.

Case presentation

A man, a teenage victim of an assault to the head, presented to the emergency department, in Baghdad, with a Glasgow Coma Score (GCS) of 4/15 (E1 M2 V1) and total right-sided paralysis. The patient’s left pupil was fixed and dilated at 5 mm, whereas the right pupil was of normal size and reacting to light.

Investigations

Urgent CT of the brain (figures 1 and 2) revealed a large left-sided frontotemporoparietal EDH with the presence of an ipsilateral sylvian AC (Galassi grade II) deep to the location of the haematoma, causing a midline shift of more than 2 cm. There was also a linear skull fracture overlying the EDH but this was not clear in the initial CT scan.

Figure 1.

Preoperative brain CT scan, showing a large left-sided frontotemporoparietal extradural haematoma with the presence of an ipsilateral sylvian arachnoid cyst (Galassi grade II) deep to the location of the haematoma, causing midline shift of more than 2 cm.

Figure 2.

Diagram of preoperative brain CT scan, showing the extradural haematoma (red) and the arachnoid cyst (blue). Illustration by TNG.

Treatment

Urgent surgical evacuation of the haematoma was performed 3 hours after the accident, leaving the associated AC intact. A large question mark frontotemporoparietal incision was performed. The source of bleeding was identified as from both branches of the left middle meningeal artery. An intraoperative decision was made to leave the cyst intact. The deep layer of the cyst was not fenestrated to the basal cisterns and the outer layer was not resected.

Outcome and follow-up

Postoperative brain CT performed on the day of presentation showed near complete evacuation of the haematoma with an improvement of the preoperative midline shift (figures 3 and 4). The patient improved and regained full consciousness after 4 days. The patient’s left pupil returned to a normal size and became reactive to light. One week after presentation, the patient was discharged from hospital without any neurological deficit. Three years after the initial trauma, the patient remains well.

Figure 3.

Immediate postoperative brain CT scan, showing near complete evacuation of haematoma with improvement of the preoperative midline shift and an intact sylvian arachnoid cyst.

Figure 4.

Diagram of postoperative brain CT scan, showing the arachnoid cyst (blue). Illustration by TNG.

Discussion

ACs account for only 1% of intracranial space-occupying lesions and in 25%–80% of cases they are located in the middle cranial fossa. The majority of ACs are detected in the first two decades of life, and are more frequent in men (66%) and in the left hemisphere.⁸

The origin of middle cranial ACs has been debated for years. Two features seem to be well documented: they have an intra-arachnoid location,^9–14 and they have potential expanding properties, competing with the brain for space,¹⁵ as confirmed by serial CT scans of Geissinger et al.¹⁶ There is an inverse relationship between the extent of communication between the cystic cavity and the subarachnoid space and the size of these cysts.¹⁵

According to the Galassi classification of ACs, there are three differing types of cyst, characterised by increasing severity^{15 17}:

• Type I is small, freely communicating, spindle shaped and limited to the anterior aspect of the temporal fossa. They exert no mass effect.

• Type II is medium sized and triangular or quadrangular in shape, they occupy the anterior and middle part of the temporal fossa, extending superiorly across the sylvian fissure.

• Type III is huge, non-communicating, oval or round cysts occupying the majority of the temporal fossa, they exert a striking mass effect. Cranial deformities and angiographic pathological changes are usually pronounced.

Traumatic EDHs occur in approximately 1%–5% of all head injuries.¹⁸ Type 1 EDHs are acute haematomas, characterised by a hyperattenuating clot and a swirling lucency on CT caused by active bleeding and clot formation. Type 2 EDHs are subacute, these are recognised by homogeneous hyperattenuating clots. Type 3 EDHs are chronic bleeds, the clots undergo breakdown and appear hypoattenuating as the breakdown products are absorbed.⁷ The middle meningeal artery has been reported to be the major source of bleeding in more than 50% of traumatic EDHs, followed by the middle meningeal vein, dural sinus tears and lastly, diploic vein tears.^{18 19}

It is well known that the presence of an intracranial AC increases the risk of a subdural haematoma after head injury.^{1 2} The mechanism may be related to tearing of bridging veins that run in the ACs. Conversely, ACs are rarely complicated by EDHs.³

A literature review on the subject revealed only seven previously reported cases of EDH associated with the presence of ACs.^{1 3–7} We have performed a comparative analysis of the cases including the patient we have reported.

The age of patients ranges from 13 to 56 years with a mean of 24 years. All are male and have sylvian ACs with ipsilateral, supratentorial EDHs. Mechanisms of injury include motor cycle accident (three patients), direct trauma (three patients), road traffic accident (one patient) and fall on the ground (one patient). Four patients presented with an initial GCS of 15, two patients with 14, one patient with 9 and one with 4.

Presenting features varied across the patients and included initial anisocoria, progressive headache, vomiting and hemiparesis. Skull fractures, identified by CT scan, were present in five out of eight patients. The source of the EDH was arterial in four patients and venous in the other four patients. Three of the patients had large EDHs extending over the frontotemporoparietal area, three had pure temporal haematomas, one had a frontal haematoma and the other a parietal haematoma. Six of the ACs were on the left side and two on the right side. The grade of the AC was III in one patient, III in five and the others were not specified. Six patients had intact ACs intraoperatively, one was collapsed and one was not specified.

Surgical management of the EDH was employed in six of the eight patients, two were treated conservatively owing to their 15/15 GCS and mild head injuries. Four of the ACs were managed by resection, one by resection and fenestration, three were left intact and one was not specified. The Glasgow Outcome Score was 5 for all patients with no remnant neurological deficits. The dataare shown in table 1.

Table 1.

The patient data from literature review

Author/year	Age (years)/mechanism/ severity of injury	Initial GCS out of 15 and the associated deficit	Skull	Site of ipsilateral EDH/source of EDH	Site/grade of sylvian AC	Op findings of AC	Management of EDH	Management of the AC	GOS
Galassi et al 1 1986	13/MCA/severe	14/anisocoria, vomiting	+	Frontal/ arterial	Left/2	Intact	Emergency evacuation	Resection and fenestration	5
Galassi et al 1 1986	16/RTA/severe	9/anisocoria, (after 2 days)	+	Parietal/ arterial	Left/2	Intact	Emergency evacuation	Resection	5
Molloy et al 4 1991	18/direct trauma/mild	15/vomiting	−	Temporal/ venous	Right/NS	collapsed	Observation	NS	5
Kadioğly et al 5 1994	37/direct trauma/mild	15/R side weakness, (after 2 days)	−	Temporal/ venous	Right/NS	NS	Observation	Resection	5
Mastronardi et al 6 1999	15/MCA/severe	14/anisocoria, R side weakness	+	Frontotemporoparietal/ venous	Left/2	Intact	Emergency evacuation	AC left intact	5
Boviatsis et al 3 2003	56/fall on ground/mild	15/progressive H/A only	−	Temporal/ venous	Left/2	Intact	Emergency evacuation	AC left intact	5
Seddighi et al 7 2012	23/MCA/mild	15/progressive H/A only	+	Frontotemporoparietal/ arterial	Left/3	Intact	Emergency evacuation	Resection	5
–	17/direct trauma/severe	4/anisocoria, R side paralysis	+	Frontotemporoparietal/ arterial	Left/2	Intact	Emergency evacuation	AC left intact	5

+, fracture; −, no fracture.

AC, arachnoid cyst; EDH, extradural haematoma; GCS, Glasgow Coma Score; GOS, Glasgow Outcome Score; H/A, headache; MCA, motor cycle accident; NS, not specified; RTA, road traffic accident.

The decision to open the associated AC in the case of EDH is still debated. The authors’ opinion is that there is no indication for cyst intervention unless any of the following conditions are met: there is a bleeding into the AC, the patient was symptomatic prior to the traumatic EDH, the AC appears to be Galassi grade III or tense intraoperatively. The time required for marsupialisation of the cyst, that is, resection of outer layer and microscopic or endoscopic fenestration of the inner layer into the deep cisterns, must also be considered.^{8 20 21}

The priority should be evacuation of the EDH. However, benign ACs are not without complications, among these are: subdural hygromas, SDH and intra-attic haematomas.

In our case, the AC was of low tension, the patient was previously asymptomatic, the preoperative GCS was 4 and a large cavity resulted from the haematoma evacuation, as such the decision was made not to open the ipsilateral AC in the same sitting.

If a decision is made to intervene on the AC, the most appropriate approach is to open the dura using microsurgical or endoscopic techniques, peel off the external layer of arachnoid away, then fenestrate the internal layer into the basal cisterns ensuring cerebrospinal fluid (CSF) drainage, thus preventing cyst recurrence. This should be performed in the same surgical sitting. Alternatively, a cystoperitoneal shunt can be considered in a symptomatic or enlarging cyst.²²

It is also worth discussing the management of acute traumatic SDH when it occurs in combination with pre-existing AC. Acute SDHs are most commonly treated with craniotomy.²³ As a result of this, and that to evacuate the SDH the dura must be opened, associated ACs are most appropriately intervened on during evacuation of the SDH.²⁴ The method of intervention should be the same as described previously for AC intervention.

Learning points.

• Intracranial arachnoid cysts are subject to haemorrhagic complications and ipsilateral extradural haematomas are one of the rare but most clinically significant of these.

• The decision regarding whether to perform arachnoid cyst resection or fenestration should be individualised to the specific patient presentation, as well as the sizes of both the arachnoid cyst and the associated ipsilateral extradural haematoma.

• Of particular importance in the clinical presentation is the presence of neurological symptoms or signs caused by the arachnoid cyst prior to the traumatic incident.