Technical difficulties in the microsurgical dissection of the sylvian fissure and cistern: prospective identification of the responsible factors in 152 elective neurological surgeries

✓ In 15% of patients with spontaneous subarachnoid hemorrhage (SAH), the source of bleeding cannot be determined despite repeated cerebral angiography. However, some patients diagnosed as having “SAH of unknown cause” actually harbor undetected aneurysms. The authors report six patients with SAH who, despite multiple negative cerebral angiograms, underwent exploratory surgery due to a high clinical and radiographic suspicion for the presence of an aneurysm. Brain computerized tomography (CT) scans revealed blood located mainly in the basal frontal interhemispheric fissure in four patients, in the sylvian fissure in one patient, and in the interpeduncular cistern in one patient. The patients were evaluated as Hunt and Hess Grades I to III, and had undergone at least two high-quality cerebral angiograms that did not reveal an aneurysm. Vasospasm was visualized in two patients. Three patients rebled while in the hospital. Exploratory surgery was performed at an average of 12 days post-SAH. Five aneurysms were discovered at surgery and were successfully clipped. All four patients with interhemispheric blood were found to have an anterior communicating artery (ACoA) aneurysm. The patient with blood in the sylvian fissure was found to have a middle cerebral artery aneurysm. These aneurysms were partially thrombosed. No aneurysm was detected in the patient with interpeduncular SAH, despite extensive basilar artery exploration. Five patients had an excellent outcome and one patient developed diabetes insipidus. These results show that exploratory aneurysm surgery is warranted, despite repeated negative cerebral angiograms, if the patient manifests the classical signs of SAH with CT scans localizing blood to a specific cerebral blood vessel (particularly the ACoA) and if a second SAH is documented at the same site.

Download Full-text

WHO DISCOVERED THE SYLVIAN FISSURE?

Neurosurgery ◽

10.1227/01.neu.0000327693.86093.3f ◽

2008 ◽

Vol 63 (4) ◽

pp. 623-628 ◽

Cited By ~ 12

Author(s):

Massimo Collice ◽

Rosa Collice ◽

Alessandro Riva

Keyword(s):

Sylvian Fissure

Download Full-text

Sensorimotor Integration in S2, PV, and Parietal Rostroventral Areas of the Human Sylvian Fissure

Journal of Neurophysiology ◽

10.1152/jn.00733.2006 ◽

2007 ◽

Vol 97 (2) ◽

pp. 1288-1297 ◽

Cited By ~ 54

Author(s):

Leighton B. Hinkley ◽

Leah A. Krubitzer ◽

Srikantan S. Nagarajan ◽

Elizabeth A. Disbrow

Keyword(s):

Tactile Stimulus ◽

Region Of Interest ◽

Sylvian Fissure ◽

Fmri Data ◽

Movement Condition ◽

Manual Exploration ◽

Movement Component ◽

The Right ◽

Proprioceptive Inputs ◽

Similar Location

We explored cortical fields on the upper bank of the Sylvian fissure using functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) to measure responses to two stimulus conditions: a tactile stimulus applied to the right hand and a tactile stimulus with an additional movement component. fMRI data revealed bilateral activation in S2/PV in response to tactile stimulation alone and source localization of MEG data identified a peak latency of 122 ms in a similar location. During the tactile and movement condition, fMRI revealed bilateral activation of S2/PV and an anterior field, while MEG data contained one source at a location identical to the tactile-only condition with a latency of 96 ms and a second rostral source with a longer latency (136 ms). Furthermore, Region-of-interest analysis of fMRI data identified increased bilateral activation in S2/PV and the rostral area in the tactile and movement condition compared with the tactile only condition. An area of cortex immediately rostral to S2/PV in monkeys has been called the parietal rostroventral area (PR). Based on location, latency, and conditions under which this field was active, we have termed the rostral area of human cortex PR as well. These findings indicate that humans, like non-human primates, have a cortical field rostral to PV that processes proprioceptive inputs, both S2/PV and PR play a role in somatomotor integration necessary for manual exploration and object discrimination, and there is a temporal hierarchy of processing with S2/PV active prior to PR.

Download Full-text

The hyperdense sylvian fissure MCA ”dot“ sign: a marker of acute CT ischemia

Stroke ◽

10.1161/str.32.suppl_1.346-b ◽

2001 ◽

Vol 32 (suppl_1) ◽

pp. 346-346

Author(s):

Philip A Barber ◽

Andrew M Demchuk ◽

Mark E Hudon ◽

Warwick Pexman ◽

Michael D Hill ◽

...

Keyword(s):

Middle Cerebral Artery ◽

Cerebral Artery ◽

Symptom Onset ◽

Clinical Information ◽

Diagnostic Value ◽

Sylvian Fissure ◽

Ct Scans ◽

Kappa Statistics ◽

Computed Tomographic ◽

Good Range

P40 Background: The hyperdense appearance of the middle cerebral artery is now a familiar early warning of large cerebral infarction, brain oedema and poor prognosis. Less well described, however, is the hyperdensity associated with embolic occlusion of branches of the middle cerebral artery seen in the sylvian fissure (MCA ”dot“ sign). The aim of this study was to define this sign, and to determine the incidence, its diagnostic value, and reliability. Methods: Computed tomographic (CT) scans performed on patients with acute ischemic stroke within 3 hours of symptom onset were analysed for signs of thromboembolic stroke and evidence of early CT ischemia. Two neuroradiologists and two stroke neurologists initially blinded to all clinical information, and then with knowledge of the affected hemisphere evaluated scans for the presence of a hyperdense MCA sign (HMCA), a hyperdense sylvian fissure MCA ”dot“ sign, and for early MCA territory ischemic changes. Results: Of 100 consecutive patients presenting within 3 hours of symptom onset early CT ischemia was seen in 74 % of the baseline CT scans. The HMCA sign was seen in 5% of CT scans whereas the MCA ”dot“ sign was seen in 16% of which 2 were associated with a HMCA sign. The presence of a HMCA sign was associated with a greater probability of dependence or death than when a MCA ”dot“ sign was observed or no hyperdensity was seen (P<0.05). All 5 patients with a HMCA sign, including 2 with an associated MCA ”dot“ sign were either dead or dependent at 3 months. Patients with a dot sign alone had independent outcomes in 64% of cases (P<0.8). Balanced kappa statistics for both signs were in the moderate to good range when the side of stroke was known. Conclusions: The hyperdense sylvian fissure MCA ”dot“ sign is an early marker of thromboembolic occlusion of the distal MCA and of its branches.

Download Full-text