David W. Newell
Arun Paul Amar and David W. Newell
Emun Abdu, Daniel F. Hanley and David W. Newell
Spontaneous intracerebral hemorrhage is a serious public health problem and is fatal in 30%–50% of all occurrences. The role of open surgical management of supratentorial intracerebral hemorrhage is still unresolved. A recent consensus conference sponsored by the National Institutes of Health suggests that minimally invasive techniques to evacuate clots appear to be a promising area and warrant further investigation. In this paper the authors review past, current, and potential future methods of treating intraparenchymal hemorrhages with minimally invasive techniques and review new data regarding the role of stereotactically placed catheters and thrombolytics.
Marcelo D. Vilela and David W. Newell
The aim of this study was to review the historical developments and current status of superficial temporal artery (STA) to middle cerebral artery (MCA) bypass.
A literature review was performed to review the origins and current uses of the STA bypass procedure in neurosurgery.
The idea of providing additional blood supply to the brain to prevent stroke and maintain neurological function has been present in the mind of neurosurgeons for many decades. In 1967 the first STA–MCA bypass was done by M. G. Yaşargil, and an enormous step was made into the field of microneurosurgery and cerebral revascularization. During the decades that followed, this technique was used as an adjuvant or a definitive surgical treatment for occlusive disease of the extracranial and intracranial cerebral vessels, skull base tumors, aneurysms, carotid–cavernous fistulas, cerebral vasospasm, acute cerebral ischemia, and moyamoya disease. With the results of the first randomized extracranial–intracranial (EC–IC) bypass trial and the development of endovascular techniques such as angioplasty for intracranial atherosclerotic disease and cerebral vasospasm, the indications for STA–MCA bypass became limited. Neurosurgeons continued to perform EC–IC bypasses as an adjuvant to clipping of aneurysms and in the treatment of skull base tumors and moyamoya disease; the procedure is less commonly used for atherosclerotic carotid artery occlusion (CAO) with definite evidence of hemodynamic insufficiency. The evidence that patients with symptomatic CAO and “misery perfusion” have an increased stroke risk has prompted a second trial for evaluating EC–IC bypass for stroke prevention. The Carotid Occlusion Surgery Study is a new trial designed to determine whether STA–MCA bypass can reduce the incidence of stroke in these patients. New trials will also reveal the role of the STA–MCA bypass in the prevention of hemorrhages in moyamoya disease.
The role of STA–MCA bypass in the management of cerebrovascular disease continues to be refined and evaluated using advanced imaging techniques and by performing randomized trials for specific purposes, including symptomatic CAO.
David W. Newell, Andrew T. Dailey and Stephen L. Skirboll
✓ The authors describe the use of a microanastomotic device to perform intracranial end-to-end vascular anastomoses. Direct end-to-end anastomosis was performed between the superficial temporal artery and branches of the middle cerebral artery (MCA) in three patients. Two patients had moyamoya disease, with severe proximal MCA disease, and one suffered an internal carotid artery occlusion with poor collateral flow. All patients reported a history of recent ischemic symptoms. Each anastomosis was accomplished in less than 15 minutes with technically satisfactory results. Postoperative angiographic studies demonstrated patency of the bypasses in all patients.
Mohan R. Sharma, David W. Newell and Gerald A. Grant
Andrew N. Nemecek, David W. Newell and Robert Goodkin
✓ Of the many causes of vertebrobasilar insufficiency (VBI), extrinsic compression of the vertebral artery (VA) is relatively uncommon. A syndrome of VBI caused by extrinsic compression of the VA secondary to head rotation has been termed positional vertebrobasilar ischemia. The authors present a case of transient VBI caused by herniation of a cervical disc. Transcranial Doppler ultrasonography was used preoperatively to confirm the diagnosis and intraoperatively to monitor cerebral perfusion and to confirm that adequate decompression of the VA had been achieved.
David W. Newell, Gavin W. Britz and Jonathan Brisman
David W. Newell, Rune Aaslid, Renate Stooss and Hans J. Reulen
✓ Intracranial pressure (ICP) and continuous transcranial Doppler ultrasound signals were monitored in 20 head-injured patients and simultaneous synchronous fluctuations of middle cerebral artery (MCA) velocity and B waves of the ICP were observed. Continuous simultaneous monitoring of MCA velocity, ICP, arterial blood pressure, and expired CO2 revealed that both velocity waves and B waves occurred despite a constant CO2 concentration in ventilated patients and were usually not accompanied by fluctuations in the arterial blood pressure. Additional recordings from the extracranial carotid artery during the ICP B waves revealed similar synchronous fluctuations in the velocity of this artery, strongly supporting the hypothesis that blood flow fluctuations produce the velocity waves. The ratio between ICP wave amplitude and velocity wave amplitude was highly correlated to the ICP (r = 0.81, p < 0.001). Velocity waves of similar characteristics and frequency, but usually of shorter duration, were observed in seven of 10 normal subjects in whom MCA velocity was recorded for 1 hour. The findings in this report strongly suggest that B waves in the ICP are a secondary effect of vasomotor waves, producing cerebral blood flow fluctuations that become amplified in the ICP tracing, in states of reduced intracranial compliance.