Monitoring Ischemic Cerebral Injury in Spontaneously Hypertensive Rats by Diffusion Tensor Imaging

AIM

We have applied diffusion tensor imaging (DTI) to interrogate microstructural changes in white matter integrity in a widely used middle cerebral artery occlusion (MCAO) model of cerebral ischemia.

MATERIAL AND METHODS

We performed ex vivo DTI 35 days after 60 minutes transient focal ischemia in male spontaneously hypertensive rats and generated fractional anisotropy (FA), mean, axial and radial diffusivity maps. Regions of interest corresponding to external capsule (EC), corpus callosum (CC) and internal capsule (IC) were compared among sham and stroked rats. We compared tractographic projections of white matter fiber patterns and examined white matter integrity by Luxol fast blue histological analysis. We also determined infarct lesion volumes at 24 hours post-ischemia by T2-weighted magnetic resonance imaging (MRI) or at 35 days by histological staining with cresyl violet.

RESULTS

We found alterations in EC and IC, but not CC, as represented by decreased FA and increased mean, axial and radial diffusivities. The size of the ischemic lesion detected subacutely by T2-weighted MRI or at 35 days by histological staining correlated with the decline in FA in the affected structures. Tractography revealed disruption of fiber trajectories through the EC and reorientation of fibers within the caudate/putamen of rats subjected to MCAO. Similarly, loss of white matter integrity in the EC and increased white matter density in the caudate/putamen along the infarct border zone was evidenced by Luxol fast blue staining.

CONCLUSION

Diffusion tensor imaging therefore allows for monitoring of white matter injury and reorganization in hypertensive rats.

Emotion recognition deficits associated with ventromedial prefrontal cortex lesions are improved by gaze manipulation

Facial emotion recognition is a critical aspect of human communication. Since abnormalities in facial emotion recognition are associated with social and affective impairment in a variety of psychiatric and neurological conditions, identifying the neural substrates and psychological processes underlying facial emotion recognition will help advance basic and translational research on social-affective function. Ventromedial prefrontal cortex (vmPFC) has recently been implicated in deploying visual attention to the eyes of emotional faces, although there is mixed evidence regarding the importance of this brain region for recognition accuracy. In the present study of neurological patients with vmPFC damage, we used an emotion recognition task with morphed facial expressions of varying intensities to determine (1) whether vmPFC is essential for emotion recognition accuracy, and (2) whether instructed attention to the eyes of faces would be sufficient to improve any accuracy deficits. We found that vmPFC lesion patients are impaired, relative to neurologically healthy adults, at recognizing moderate intensity expressions of anger and that recognition accuracy can be improved by providing instructions of where to fixate. These results suggest that vmPFC may be important for the recognition of facial emotion through a role in guiding visual attention to emotionally salient regions of faces.

Microsurgical resection of tumors of the lateral and third ventricles: operative corridors for difficult-to-reach lesions

Tumors of the lateral and third ventricles are cradled on all sides by vital vascular and eloquent neural structures. Microsurgical resection, which always requires attentive planning, plays a critical role in the contemporary management of these lesions. This article provides an overview of the open microsurgical approaches to the region highlighting key clinical perspectives.

Supracerebellar transtentorial approach to the tentorial incisura and beyond

The supracerebellar transtentorial approach via a suboccipital craniotomy provides a corridor to reach lesions of the tentorial incisura and supratentorial lesions of the posterior medial basal temporal lobe, such as lesions of the posterior parahippocampal and fusiform gyri. The supracerebellar transtentorial approach obviates the need for either retraction of eloquent cortex or a transcortical route to reach lesions in this region. We present three cases that demonstrate the utility of this approach: a left-sided tentorial meningioma with superior projection, a left-sided posterior parahippocampal cavernous malformation, and a left-sided posterior parahippocampal grade 2 oligodendroglioma. The video can be found here: https://youtu.be/OLnzUGZfUqk .

Treatment of Supraclinoid Internal Carotid Artery Iatrogenic Pseudoaneurym with Extracranial-to- Intracranial Bypass and Trapping: Demonstration of Technique with Video Presentation

Intracranial pseudoaneurysms (IP) represent about 1% of all patients presenting with an intracranial aneurysm. In true intracranial aneurysms, the intima, internal elastic lamina, and media are disrupted, but the adventitia is intact. In pseudoaneurysms, there is disruption of all three layers of the arterial wall, thus resulting in higher rates of re-hemorrhage and thrombus formation. Patients with IP commonly present with subarachnoid hemorrhage or thromboembolic complications. Until now, no specific guidelines have been established for the ideal treatment of pseudoaneurysms. Although IP have higher rates of morbidity and mortality compared to true intracranial aneurysms, surgical treatment can prevent catastrophic hemorrhagic and thrombotic complications. Despite recent advances in endovascular techniques that allow safe approaches to complicated intracranial vascular pathologies, vascular trapping and bypass remains the definitive and safe treatment for IP. Based on our experience and related literature, we consider the latter treatment in experienced hands as an effective and decisive treatment modality to prevent the devastating complications of IP. In this article, we discuss the surgical management of iatrogenic intracranial internal carotid artery pseudoaneurysms by trapping, and extracranial-intracranial bypass through a case illustration in which the technique is demonstrated via a video presentation.

Can Sonography Distinguish a Supraorbital Notch From a Foramen?

Diagnostic tools for evaluating the supraorbital rim in preparation for nerve decompression surgery in patients with chronic headaches are currently limited. We evaluated the use of sonography to diagnose the presence of a supraorbital notch or foramen in 11 cadaver orbits. Sonographic findings were assessed by dissecting cadaver orbits to determine whether a notch or foramen was present. Sonography correctly diagnosed the presence of a supraorbital notch in 7 of 7 cases and correctly diagnosed a supraorbital foramen in 4 of 4 cases. We found that sonography had 100% sensitivity in diagnosing a supraorbital notch and foramen. This tool may therefore be helpful in characterizing the supraorbital rim preoperatively and may influence the decision to use a transpalpebral or endoscopic approach for supraorbital nerve decompression as well as the decision to use local or general anesthesia.

Ventromedial prefrontal cortex damage alters relative risk tolerance for prospective gains and losses

One paradigmatic example of "irrational" bias in human economic decision-making-known as the "reflection effect"-is a tendency to prefer sure amounts over risky gambles in situations involving potential gain, but to prefer risky gambles over sure amounts in situations involving potential loss. To date, there is no causal evidence regarding the neural basis of the reflection effect. The ventromedial prefrontal cortex (vmPFC) is believed to play a critical role in mediating value-based decision-making. In this study, we administered a behavioral test of the reflection effect to three groups of subjects: neurosurgical patients with focal bilateral vmPFC lesions, neurosurgical patients with lesions outside vmPFC, and neurologically healthy adults. Subjects made a series of choices between a sure amount (e.g., gain of $50) and a gamble (e.g., 50% chance of gaining $100, 50% chance of gaining $0). Half the trials featured potential gains while the other half featured potential losses. The sure amounts varied across trials. Relative to the two comparison groups, the vmPFC lesion patients exhibited a significantly greater reflection effect; more gambles selected in the loss condition and fewer gambles selected in the gain condition. This finding demonstrates a critical role for vmPFC in governing susceptibility to bias in decision-making.

Recipient vessel selection in the difficult neck: Outcomes of external carotid artery transposition and end-to-end microvascular anastomosis

BACKGROUND

Selection of recipient vessels for head and neck microvascular surgery may be limited in the previously dissected or irradiated neck. When distal branches of the external carotid artery (ECA) are unavailable, additional options for arterial inflow are needed. Here we propose high ligation of the ECA and transposition toward the lower neck as an alternative.

METHODS

After obtaining institutional approval, patients who underwent head and neck tumor resection and simultaneous free flap reconstruction were identified over a 5-year period. Patients whose recipient artery was listed in the operative report were included. Chart review was performed to identify patient demographics, operative details, and patient and flap complications. In cases where the ECA was used, the artery was traced distally with care taken to protect the hypoglossal nerve. The ECA was then divided and transposed toward the lower neck where an end-to-end microvascular anastomosis was performed.

RESULTS

The recipient artery used for head and neck microsurgery was available for 176 flaps, and the facial (n = 127, 72.2%) and external carotid (n = 19, 10.8%) arteries were most commonly used. There were 0 flap thromboses in the ECA group compared to 3 flap thromboses that occurred with other recipient arteries (P = 1.00). No cases of first bite syndrome or hypoglossal nerve injury were identified.

CONCLUSIONS

The ECA may be transposed toward the lower neck and used for end-to-end microvascular anastomosis without complication of hypoglossal nerve injury or first bite syndrome. This method may be considered an alternative in patients with limited recipient vessel options for head and neck microsurgery. © 2015 Wiley Periodicals, Inc. Microsurgery 37:96-100, 2017.

Microsurgical clipping of a giant vertebrobasilar junction aneurysm under hypothermic circulatory arrest

Giant posterior circulation aneurysms pose a significant challenge to neurovascular surgeons. Among various treatment methods that have been applied individually or in combination, clipping under hypothermic circulatory arrest (HCA) is rarely used. We present a 62-year-old man who initially underwent coil occlusion of the right vertebral artery (VA) for a 2.5 cm giant vertebrobasilar junction (VBJ) aneurysm. His neurological condition had declined gradually and the aneurysm grew to 4 cm in size. The patient underwent clip reconstruction of giant VBJ aneurysm under HCA. His postoperative course was prolonged due to his preexisting neurological deficits. His preoperative Modified Rankin Score was 5, and improved postoperatively to 3 at three and six months, and to 2 at one year. The video can be found here: http://youtu.be/L53SiLV8eJY.

Glioblastoma multiforme in Klippel-Trenaunay-Weber syndrome: a case report

Introduction

Klippel-Trenaunay-Weber syndrome (KTWS) is a rare syndrome in which patients usually present with cutaneous hemangiomas, venous varicosities, and bone and soft tissue hypertrophy of the affected limb. Intracranial lesions in patients with KTWS are extremely rare, and are generally reported as single cases in the literature. We describe a rare case, where a patient with KTWS was found with a hemorrhagic grade IV astrocytoma. Although central nervous system abnormalities such as intracranial aneurysms and cerebral and spinal cord cavernomas have been described in patients with KTWS, to the best of our knowledge, this is the first report of an association between glioblastoma multiforme (grade IV astrocytoma) and KTWS in the English-language medical literature.

Case presentation

A 61-year-old white Caucasian man with a history of KTWS presented with seizures. Left upper and lower extremity hypertrophy, left foot, leg and ear gigantism and left-sided abdominal capillary hemangiomas were noted in the physical examination. Cranial computed tomography (CT) and magnetic resonance imaging (MRI) were obtained, showing a heterogeneous lesion in the cingulate gyrus, with peripheral and central areas of T1 hyperintensity and layering T2 hypointensity consistent with a hemorrhage. A right parasagittal frontal craniotomy was performed with an interhemispheric approach. We had difficulty controlling the bleeding with bipolar electrocautery during surgery and finally were able to stop the bleeding using surgicel and gelfoam. Postoperative cranial CT and MRI scans showed intraparenchymal hemorrhage centered within the medial right frontal lobe. There was no increase in hematoma size in consecutive CT scans.

Conclusions

Co-occurrence of vascular abnormalities with KWTS should be taken into consideration to avoid perilous preoperative and postoperative complications.

Microsurgical anatomy and variations of the anterior clinoid process

AIM

The aim of this study was to better define the microsurgical anatomy of the supra/parasellar region and describe variations of the anterior clinoid process (ACP).

MATERIAL AND METHODS

Fifteen formalin-fixed cadaver heads and 25 dry skulls were used to define the microsurgical anatomy of the ACP and related structures. The presence of the caroticoclinoid foramen (CaCF) as well as other relevant measurements were all noted. Radiological examination of the CaCF was also demonstrated on dry skulls.

RESULTS

Interosseous bridges, which form between the anterior and middle clinoid processes or connect all three (anterior, middle and posterior) clinoid processes, were found in 30% of the specimens. The average basal width, length and thickness of the ACP were 7.3 mm, 9.7 mm and 5.4 mm, respectively. Length of the optic nerve (ON) up to the falciform ligament (FL) was 10.9 mm; length of the ON under the FL was 2.7 mm; length of ON after removal of the ACP and unroofing the optic canal was 21.1 mm.

CONCLUSION

This study contributes to the relationship of important vascular, neural, bone and dural layers of this region and also demonstrates the variations of ACP by means of microsurgical dissections and radiological examinations.

Surgical treatment of adult moyamoya disease with combined STA-MCA bypass and EDAS: demonstration of technique in video presentation

The natural history of Moyamoya disease (MD) is variable. Moyamoya disease in children mostly presents with progressive ischemic complications and in adulthood it tends to present with hemorrhage. Surgical strategies depend on augmenting cerebral blood flow to the anterior cerebral circulation. Revascularization is the mainstay treatment for MD. We introduce a 31 year old female with a history of MD and leftsided revascularization as a child, who presented with headache, confusion, and worsening left sided weakness. Cranial computed tomography (CT) showed a right sided putaminal hemorrhage. Cerebral angiogram with selective external runs revealed MD, hypoplastic parietal branch of the superficial temporal artery (STA) on the right side and previous revascularization on the left side. Thus, our decision was made to perform a bypass with the frontal branch of the STA to an M3-M4 segment of the middle cerebral artery and an encephaloduroarteriomyosynangiosis with the parietal branch of the STA. The patient's postoperative course was uneventful. Postoperative CT angiogram confirmed patency of bypass. This technique provides immediate revascularization and seems to provide risk reduction for ischemic and hemorrhagic stroke. We review the natural history and surgical treatment of MD along with a case presentation in which surgical technique is demonstrated in video.

Ventromedial prefrontal cortex is critical for the regulation of amygdala activity in humans

BACKGROUND

Dysfunction in the ventromedial prefrontal cortex (vmPFC) is believed to play a pivotal role in the pathogenesis of mood and anxiety disorders. Leading neurocircuitry models of these disorders propose that hypoactivity in the vmPFC engenders disinhibited activity of the amygdala and, consequently, pathologically elevated levels of negative affect. This model predicts that a selective loss or diminution of function of the vmPFC would result in heightened activity of the amygdala. Although this prediction has been borne out in rodent lesion and electrophysiologic studies using fear conditioning and extinction paradigms, there has not yet been a definitive test of this prediction in humans.

METHODS

We tested this prediction through a novel use of functional magnetic resonance imaging in four neurosurgical patients with focal, bilateral vmPFC damage.

RESULTS

Relative to neurologically healthy comparison subjects, the patients with vmPFC lesions exhibited potentiated amygdala responses to aversive images and elevated resting-state amygdala functional connectivity. No comparable group differences were observed for activity in other brain regions.

CONCLUSIONS

These results provide unique evidence for the critical role of the vmPFC in regulating activity of the amygdala in humans and help elucidate the causal neural interactions that underlie mental illness.

Clip reconstruction of an 8 cm giant internal carotid artery bifurcation aneurysm: microsurgical technique

Thrombosed giant intracranial aneurysms usually present with symptoms and signs from their mass effect. Although multiple treatment options are available, direct clip reconstruction with thromboendarterectomy remains the gold standard. Here we present a 66-year-old man with seizure, aphasia and hemiparesis. Work-up revealed a giant partially thrombosed aneurysm of the internal carotid artery bifurcation with surrounding vasogenic edema. He underwent clip reconstruction of the aneurysm via a cranio-orbital approach. Although we prepared for bypass with the radial artery and/or the superficial temporal artery, we were able to clip-reconstruct the aneurysm without bypass. The patient improved upon his pre-morbid state after surgery and made an excellent recovery. The video can be found here: http://youtu.be/P_10hRQFuPo .

Ventromedial prefrontal cortex damage alters resting blood flow to the bed nucleus of stria terminalis

The ventromedial prefrontal cortex (vmPFC) plays a key role in modulating emotional responses, yet the precise neural mechanisms underlying this function remain unclear. vmPFC interacts with a number of subcortical structures involved in affective processing, including the amygdala, hypothalamus, periaqueductal gray, ventral striatum, and bed nucleus of stria terminalis (BNST). While a previous study of non-human primates shows that vmPFC lesions reduce BNST activity and anxious behavior, no such causal evidence exists in humans. In this study, we used a novel application of magnetic resonance imaging (MRI) in neurosurgical patients with focal, bilateral vmPFC damage to determine whether vmPFC is indeed critical for modulating BNST function in humans. Relative to neurologically healthy subjects, who exhibited robust rest-state functional connectivity between vmPFC and BNST, the vmPFC lesion patients had significantly lower resting-state perfusion of the right BNST. No such perfusion differences were observed for the amygdala, striatum, hypothalamus, or periaqueductal gray. This study thus provides unique data on the relationship between vmPFC and BNST, suggesting that vmPFC serves to promote BNST activity in humans. This finding is relevant for neural circuitry models of mood and anxiety disorders.

The cadaveric perfusion and angiography as a teaching tool: imaging the intracranial vasculature in cadavers

Background and Study Aim To enhance the visualization of the intracranial vasculature of cadavers under gross examination with a combination of imaging modalities. Material and Methods A total of 20 cadaver heads were used to test two different perfusion techniques. First, fixed cadaver heads were perfused with water; second, fresh cadavers were perfused with saline and 10% formalin. Subsequently, brains were removed and fixed. The compounds used were silicone rubber, silicone rubber mixed with powdered barium sulfate, and silicone rubber mixed with tantalum dioxide prepared by the first perfusion technique and gelatin mixed with liquid barium prepared with the second technique. Conventional X-ray imaging, computed tomography (CT), dynamic computed tomography (dCT), and postprocessing three-dimensional (3D) images were used to evaluate all the heads. Results Gelatinized barium was better visualized when compared with tantalum dioxide in conventional X-ray images. The blood vessels injected with either tantalum dioxide or gelatinized barium demonstrated a higher enhancement than the surrounding soft tissues with CT or dCT. The quality of the 3D reconstruction of the intracranial vasculature was significantly better in the CT images obtained from the gelatinized barium group. Conclusions Radiologic examinations of the heads injected with gelatinized barium facilitates the 3D understanding of cerebrovascular anatomy as an important tool for neuroanatomy training.

Ventromedial prefrontal cortex mediates visual attention during facial emotion recognition

The ventromedial prefrontal cortex is known to play a crucial role in regulating human social and emotional behaviour, yet the precise mechanisms by which it subserves this broad function remain unclear. Whereas previous neuropsychological studies have largely focused on the role of the ventromedial prefrontal cortex in higher-order deliberative processes related to valuation and decision-making, here we test whether ventromedial prefrontal cortex may also be critical for more basic aspects of orienting attention to socially and emotionally meaningful stimuli. Using eye tracking during a test of facial emotion recognition in a sample of lesion patients, we show that bilateral ventromedial prefrontal cortex damage impairs visual attention to the eye regions of faces, particularly for fearful faces. This finding demonstrates a heretofore unrecognized function of the ventromedial prefrontal cortex-the basic attentional process of controlling eye movements to faces expressing emotion.

Intraoperative dynamic assessment of the posterior communicating artery and its branches by indocyanine green videoangiography

Background:

True hemodynamic assessment of the posterior communicating artery (PComA) by preoperative angiography in terms of its perforators and configuration (adult vs. fetal vs. transitional) can be challenging in the surgical treatment of aneurysms involving the PComA, posterior cerebral artery, and basilar artery. Indocyanine green videoangiography (ICG-VA) is a widely accepted new technique in the surgical treatment of intracranial aneurysms to assess the patency of the parent artery, branches, and residual flow within the aneurysm after clipping.

Case Description:

Here we report two cases in which ICG-VA was utilized to assess either the direction of flow in the PComA or preservation of the PComA perforators with temporary clip application before dividing the PComA.

Conclusions:

Our experience is that ICG-VA can be used to assess the main trunk, and perforating branches of the PComA providing real-time, dynamic intraoperative information of the surgical field. Therefore we suggest that ICG-VA may increase the safety of surgical treatment of aneurysm involving PComA.

Single institution experience treating 104 vestibular schwannomas with fractionated stereotactic radiation therapy or stereotactic radiosurgery

The pupose of this study is to assess the long-term outcome and toxicity of fractionated stereotactic radiation therapy (FSRT) and stereotactic radiosurgery (SRS) for 100 vestibular schwannomas treated at a single institution. From 1993 to 2007, 104 patients underwent were treated with radiation therapy for vestibular schwannoma. Forty-eight patients received SRS, with a median prescription dose of 12.5 Gy for SRS (range 9.7-16 Gy). For FSRT, two different fraction schedules were employed: a conventional schedule (ConFSRT) of 1.8 Gy per fraction (Gy/F) for 25 or 28 fractions to a total dose of 45 or 50.4 Gy (n = 19); and a once weekly hypofractionated course (HypoFSRT) consisting of 4 Gy/F for 5 fractions to a total dose of 20 Gy (n = 37). Patients treated with FSRT had better baseline hearing, facial, and trigeminal nerve function, and were more likely to have a diagnosis of NF2. The 5-year progression free rate (PFR) was 97.0 after SRS, 90.5% after HypoFSRT, and 100.0% after ConFSRT (p = NS). Univariate analysis demonstrated that NF2 and larger tumor size (greater than the median) correlated with poorer local control, but prior surgical resection did not. Serviceable hearing was preserved in 60.0% of SRS patients, 63.2% of HypoFSRT patients, and 44.4% of ConFSRT patients (p = 0.6). Similarly, there were no significant differences in 5-year rates of trigeminal toxicity facial nerve toxicity, vestibular dysfunction, or tinnitus.

CONCLUSIONS

Equivalent 5-year PFR and toxicity rates are shown for patients with vestibular schwanoma selected for SRS, HypoFSRT, and ConFSRT after multidisciplinary evaluation. Factors correlating with tumor progression included NF2 and larger tumor size.

Osteotomy for laminoplasty without soft tissue penetration, performed using a harmonic bone scalpel: instrumentation and technique

BACKGROUND

Laminoplasty in the case of intramedullary spinal tumor requires care to avoid neurologic injury. The harmonic bone scalpel provides a method of laminoplasty that can be done safely and quickly for this and other indications.

PATIENTS

Five cases are presented, each of which required operative intervention, namely laminoplasty. The pathologies presented are one cervical intramedullary tumor, one thoracic intramedullary spinal mass, one lumbar extramedullary intradural tumor, and two cases of multiple lower brachial plexus nerve root avulsions requiring dorsal root entry zone (DREZ) lesion.

RESULTS

These five patients underwent laminoplasty for either tumor resection or DREZ lesion. The laminotomies were performed using the BoneScalpel™ (Misonix Inc., Farmingdale, NY, USA), which is a harmonic bone scalpel instrument. This obviated the need to place any instrument under the intact lamina. Kerrison punches and various instruments were still used, but for purposes other than the bony removal of the laminoplasty.

CONCLUSION

These cases demonstrate that the BoneScalpel™ can be used to facilitate the laminar cuts while still allowing a safe and effective operation, even in cases as delicate as an intramedullary thoracic spinal cord tumor. The mechanism of action of the harmonic bone scalpel allows osteotomies without cutting or penetrating soft tissue and also leaves minimal bony defect.

Anatomical variations of the foramen magnum, occipital condyle and jugular tubercle

AIM

The foramen magnum (FM) is a unique and complex anatomical region. The occipital condyle (OC) and jugular tubercle (JT) are the main bony structures which obscure the anterolaterally situated lesions of the FM.The aim of this study was to revisit the anatomy of the FM region and assess variations of the surrounding structures.

MATERIAL AND METHODS

Observations, on thirty dry skulls (dried specimens, 60 sides) and ten formalin-fixed cadaveric heads with perfused vessels, were carried out to define the microsurgical anatomy of the FM region. Morphometric analysis and variations of the FM, OC, JT and hypoglossal canal (HC) were noted. Radiological assessment (3D-computed tomography) of the OC, JT, HC were also conducted on dry skulls.

RESULTS

The short and long OC were demonstrated in 5% and 33% of the specimens, respectively. Flat formation of the JT was determined in 10% and tall JT was found in 23% of the specimens. The comparison of the anatomical measurements and the correspondent radiological mean values did not achieve statistical significance.

CONCLUSION

The OC and JT are the main bony prominences obstructing the anterolateral surface of the brainstem. Neurosurgeons should be familiar with variations of the structures surrounding the FM in order to perform the safest and widest exposure possible.

Early elective surgical exploration of spontaneous intracerebral hematomas of unknown origin

OBJECT

The management of non-life threatening spontaneous intraparenchymal hemorrhage with no obvious medical etiology in patients and the lack of findings on images has not been clearly defined. In general, the current practice is to treat these patients conservatively and repeat studies to rule out a treatable cause 6 weeks to 3 months later; more often than not these repeated studies fail to reveal any findings, and the patient is treated conservatively. For years, the senior author (R.C.H.) has treated these patients with early surgical exploration. This study was undertaken prospectively to ascertain the frequency of positive findings during surgical exploration.

METHODS

Between 2000 and 2007, the authors prospectively collected data from 9 cases (4 cerebellar, 4 lobar, and 1 caudate head) of unexplained intraparenchymal hemorrhages. The patient age ranged from 18 to 45 years (mean 31.2 years). All patients were normotensive, had no underlying medical problems explaining such a hemorrhage, and failed to exhibit findings on cerebral angiograms. Magnetic resonance images with contrast showed no abnormal vasculature or enhancement. Eight patients underwent elective surgical exploration in the subacute stage, and urgent decompression of the clot was necessary in 1.

RESULTS

In 7 (77.8%) of the 9 cases, histopathological examination revealed a cause for the hemorrhage (3 "cryptic" arteriovenous malformations, 3 cavernomas, and 1 neoplasm). A good outcome was achieved in all 8 patients who underwent elective surgery.

CONCLUSIONS

The authors recommend elective surgical exploration of intracerebral hematomas of unknown etiology provided that the hematoma is surgically accessible and the patient is relatively young and healthy. Early exploration and resection can provide a cure and eliminate the risk of rebleeding when a vascular lesion is found or guide further treatment in cases of tumor.