Computed tomography angiography based emergency microsurgery for massive intracranial hematoma arising from arteriovenous malformations
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.79138
Source of Support: None, Conflict of Interest: None
Background : Digital subtraction angiography (DSA) and magnetic resonance angiography are the imaging modalities for the detection of intracranial arteriovenous malformations. However, these modalities are time consuming and cannot be used in emergency conditions. Computed tomography angiography (CTA) has also been shown to reliably detect vascular disorders such as cerebral arteriovenous malformations (AVMs). Aims : The purpose of this study was to evaluate the usefulness CTA in the surgical treatment of AVMs and the hematoma evacuation. Patients and Methods : Case records of 18 patients with massive intracranial hematoma secondary to AVMs were retrospectively reviewed. All patients had emergent brain CT and CTA. Follow-up DSA was performed two to three weeks after surgery. The outcome was assessed using Glasgow Outcome Scale (GOS). Results : Emergent CTA demonstrated AVMs and defined the feeding arteries, abnormal vascular nest, and draining veins in all the patients. Fourteen patients underwent hematoma evacuation and total resection of the AVMs, and four patients had hematoma evacuation and a partial resection. Follow-up DSA demonstrated complete resection of AVM in 14/18 patients and partial resection in 4 patients. There were no deaths and none of the patients had rebleeding in the follow up. A GOS scores during follow-up were: GOS 3 in 12 patients, GOS 4 in 4 patients and GOS 2 in 2 patients. Conclusions : CTA can be a reliable and rapid diagnostic tool for detecting underlying AVM in patients presenting with intracranial hematoma and for the pretreatment planning of emergency craniotomy.
Keywords: Cerebral arteriovenous malformations, computed tomography angiography, intracranial hematoma, microsurgery
Intracranial hemorrhage is the presenting manifestation in 30-53% of patients with arteriovenous malformations (AVMs). , The annual estimated mortality and severe morbidity associated with AVMs has been 1% and 1.5%, respectively. These estimates increase with recurrent hemorrhagic episodes. , Treatment modalities of AVMs include microsurgery, ,, radiation therapy, ,, endovascular embolization, , or a combination of these treatments. ,, Most often AVMs do not require emergent treatment; however, some patients may require emergent surgical treatment: rapidly progressive neurological deterioration from mass effect or life threatening hematoma. Evacuation of hematoma may be associated with a high morbidity and mortality. In patients with intracerebral hematoma secondary to a complicated AVM, evacuation of hematoma may be possible but not complete excision of AVM due to great variability in the angioarchitecture of AVMs.
Computed tomography angiography (CTA) is a widely accepted method for detection and planning emergency surgical intervention of intracranial aneurysms. , CTA can also clearly demonstrate the three dimensional features of the feeding artery, the nidus, the draining vein, and the surrounding normal structures of the AVM and can thus be used for the diagnosis of AVMs; ,,, however, the use of CTA in the emergency evacuation of intracranial hematoma and resection of AVMs is rarely reported.  This study reports the use of CTA in the emergency evacuation intracranial hematoma and resection of AVM in 18 patients.
Between February 2004 and February 2007, 18 patients (mean age, 30.5 ± 10.2 years, range 16-40 years, 10 men and 8 woment) with an intracranial hematoma caused by AVM underwent emergency microsurgery. Hematoma volume ranged between 40 and 90 ml. Two patients had acute hydrocephalus secondary to intraventricular hematoma. Two patients deteriorated to Glasgow Coma Scale (GCS) score 4. Six had GCS scores between 4 and 8, and ten had GCS scores between 8 and 11.
The location of intracranial hematoma
All the hematomas were supratentorial in location. Four were located in a single lobe, frontal or temporal and 14 were multilobar in location: three in fronto-parietal, three in occipito- parietal, three in temporo-parietal, one in temporo-occipital, and four in fronto-temporo-parietal. Two patients had associated intraventricular hematoma.
Computed tomography angiography
All the patients had emergent CTA using 16-multidetector row spiral CT machine (GE Light Speed Ultra 16; GE Medical Systems, Waukesha, WI) and the total time for the CTA examination was between 5 and 10 min. The parameters for CTA acquisition were 1.25 mm section thickness, 0.5 mm section interval, a pitch of 3 (high quality mode), 120 kVp, and 300 mAs. Two dimensional maximum intensity projection (MIP) views and three dimensional (3D) surface-rendered and volume rendering (VR) reconstructions were reformatted from the raw image data on an Advantage workstation (Version 4.2; GE Medical Systems).
All the patients had craniotomy and evacuation of hematoma with total or partial resection of the AVMs within 120 minutes of diagnosis and the interval between the ictus and craniotomy ranged between 60 and 180 minutes. When complete resection of AVMs was difficult from the surrounding brain, hemostasis of the bleeding source was done. Two patients with acute hydrocephalus and intraventricular hematoma had placement of external ventricular drainage. Postoperatively all the patients had standard care in the neurosurgical intensive care unit.
AVM location identification by CTA and operation
CTA showed an abnormal vascular nest and draining veins. The AVM location was frontal in one patient, temporal in one patient, fronto-parietal in three patients, parietoccipital in two patients, parieto-temporal in three patients, and fronto-temporo-parietal in six patients. There were ten patients with small AVMs (size less than 3 cm), six patients with moderate-sized AVMs (between 3-6 cm), and two patients with large AVMs (>6 cm). Venous drainage was superficial in 13, deep in 3, and both in 2. The AVMs were classified according to the Spetzler-Martin (SM) grade-based on CTA images: SM grade I - 3, SM grade II - 10, SM grade III - 4, and SM grade IV - 1. Intraoperatively the location of AVM corresponded to the location of AVMs on CTA. All the patient had evacuation of hematoma. Fourteen patients had complete resection of AVM and in four patients the resection was partial.
Clinical and angiography outcome
Digital subtraction angiography (DSA) was performed two to three weeks after surgery. In 14 patients, complete resection of the AVMs was confirmed by postoperative DSA. Four patients in whom partial resection of AVM was possible, showed residual AVM components. These four patients with SM Grade III (3) and IV(1) had small deep residual nidus or early draining veins (less than 2 cm in diameter).
Glasgow Outcome Scale (GOS) six months to two years after the emergency surgery was: GOS 3 in 12 patients, GOS 4 in 4 patients and 2/18 a GOS 2 in 2 patients. There were no patients with rebleeding or death in the follow up.
An 18-year-old woman presented to the emergency unit with sudden onset severe headache and rapidly progressing into coma of two hours duration. On examination GCS score was 4 and pupils were dilated bilaterally. Emergent CT scan demonstrated a massive intracranial hematoma in the left parieto-temporal lobe with a midline shift [Figure 1]. Emergent CTA demonstrated an AVM in the parieto-temporal lobe surrounding the hematoma with a feeder from the middle cerebral artery, the nidus, and the veinous draining into the sagittal sinus. SM grade of the AVM was II [Figure 2] and [Figure 3]. The patient underwent an emergency craniotomy and hematoma evacuation and total resection of the AVM. Postoperative angiography demonstrated complete extirpation of the AVM [Figure 4] two weeks after the surgery. The patient showed a GOS score of 3 at six months follow-up.
Massive intracranial hematomas due to ruptured AVMs, frequently cause acute neurological deterioration, and become life threatening events requiring emergent surgical treatment. ,,,, The outcomes are often poor. Emergency craniotomy and evacuation hematoma with AVM resection may achieve a favorable outcome. , Stereotactic aspiration of hematoma is an option, more so in patients with hypertensive intracerebral hematoma. But this procedure is associated with a higher rate of rebleeding when compared to microsurgery.  Stereotactic aspiration has limitations in the treatment of intracerebral hematoma secondary to AVMs as direct hemostasis and confirmation of the source of the bleeding cannot be achieved. In these patients factors associated with good outcomes include: early diagnosis and prompt surgical evacuation of the hematoma with a resection of the AVM if possible and intensive care unit management. ,, However, often the immediate diagnosis of underlying AVM may not be possible. Moreover, in emergency conditions, the angioarchitecture of the AVM, including the nidus, the types of feeding arteries, and the venous drainage patterns, may not be demonstable with digital subtraction angiography (DSA) or magnetic resonance angiography (MRA); thus making complete resection of AVM difficult. Our study demonstrates the usefulness of CTA in the emergency evacuation of intracranial hematoma and resection of AVMs in 18 patients with intracerebral hematoma secondary to AVM. Four patients with SM grade III and IV AVMs had a partial resection and received gamma knife. Patients with SM Grade III-V AVMs are more frequently treated by a combination of therapies. In patients with massive hematoma caused by a complicated AVM, evacuation of hematoma may be possible but not total resection of AVM.
DSA has been the gold standard for the diagnosis of AVMs and MRA can provide critical information regarding the localization and topography of a vascular malformation. , However these imaging modalities have some limitations in demonstrating certain lesions and also time-consuming. Additionally, catheter angiography is an interventional procedure with certain risks. High-speed spiral CTA is minimally invasive and demonstrates many vascular diseases including aneurysms, AVMs and other vascular diseases. ,, In emergency situations in a patient with a intracerebral hematoma, CTA can be performed quickly at the same time head CT scan; this allows preoperative planning of evacuation of hematoma and the resection of underlying AVMs. Therefore, CTA can be useful to evaluate for underlying structural lesions, including vascular malformations when there is clinical or radiological suspicion (Class IIa; Level of Evidence: B). 
There have been many studies assessing the potential utility of CTA for the diagnosis of AVMs; ,, however, these reports have not demonstrated usefulness of CTA in pretreatment planning for emergency hematoma evacuation and resection of the AVMs. Our study demonstrated that CTA can clearly show the three dimensional features of the feeding artery, the nidus, the draining vein, and the surrounding normal structures, including the size and location of the AVM, even in patients with massive hematomas. We found draining veins were also displayed clearly in all the patients. Draining veins and external carotid artery branches can be easily identified based on typical vascular appearance and structures. In our study two image reconstruction techniques of maximum intensity projection (MIP) and volume rendering (VR) were used to evaluate the vessel distribution and entire structure of AVMs. Unlike external carotid artery branches, the draining venous structures may be irregular and enlarged. Navigated CTA allowed the feeding arteries to be distinguished from draining veins, despite the presence of a substantial intracranial hematoma,  and facilitated improved decision-making regarding endovascular or surgical treatment.  We relied on CTA for diagnosis, evaluation, and pretreatment planning in 18 patients with intracranial hematoma in the emergency unit and obtained a more complete resection of the AVMs and a more favorable outcome.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]