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Biomedical subjects

D S Samson

Publications and source records attributed to D S Samson.

35 records · Page 2Linked to original sources
PubMed1988

Subtemporal transdural use of detachable balloons for traumatic carotid-cavernous fistulas.

Endovascular use of detachable balloons has revolutionized the management of carotid-cavernous fistulas so that the goals of angiographic elimination of fistula and preservation of carotid patency can usually be achieved nonsurgically. Certain circumstances of flow dynamics and anatomy, however, make an endovascular approach difficult for even an experienced interventional neuroradiologist. Fistulas involving the posterior carotid wall at its proximal cavernous entry and the anterior carotid wall in its initial horizontal intracavernous segment, as well as very low flow fistulas at other sites, have posed particular problems. Three patients with such traumatic fistulas whose endovascular treatment failed were managed by the direct transdural introduction of balloons. Intraoperative angiography was accomplished with open internal carotid artery (ICA) catheterization and the use of a portable C-arm with a 6-in. image intensifier. After temporal craniectomy and subtemporal exposure, the course of the cavernous ICA was mapped out with spinal needles and the site of the fistula was localized by intraoperative angiography. An incision was then made in the lateral wall of the cavernous sinus, and latex balloons were manually introduced via a 7 French introducer sheath. The balloons were inflated under angiographic control and detached when the fistula was obliterated. This simple technique was initially successful in three patients; the fistula was eliminated with preservation of carotid patency. One patient suffered a recurrence of his fistula 2 months postoperatively while lifting weights, and one patient developed a new 3rd nerve palsy after operation.

Adult↗
PubMed1988

Cerebrovascular hemodynamics in arteriovenous malformation complicated by normal perfusion pressure breakthrough.

Catastrophic hyperemic states are known complications after the treatment of certain types of intracranial arteriovenous malformations (AVMs). A case is presented in which a large AVM was preoperatively embolized and later resected. There was clear intra- and postoperative evidence of edema and hemorrhage, which resulted in a fatal outcome. Regional cerebral blood flow (rCBF) data from this patient obtained with single photon emission computed tomography (SPECT) both before and after embolization were compared with data from four patients with similar size supratentorial AVMs treated and studied in a similar protocol who did not develop perfusion breakthrough. Pretreatment hemispheric rCBF was significantly reduced in this patient's ipsilateral hemisphere (50 ml/100 g/min) compared to the control group mean (83 +/- 9.5 ml/100 g/min). A similar relative depression was found in the contralateral hemisphere. After therapeutic embolization, the ipsilateral rCBF increased by 33 ml/100 g/min and the contralateral hemispheric rCBF increased by 30 ml/100 g/min; this embolization-induced increase in rCBF was significantly higher than in the control group. Acetazolamide, known to increase rCBF in normal tissue by 35 +/- 3%, resulted in a 56% augmentation of ipsilateral hemispheric flow before embolization in the reported patient vs. a 22 +/- 10% increase for the control group. Postembolization, this hyperresponsiveness to acetazolamide remained unchanged. It is possible that these hemodynamic derangements may indicate a dissociation between the vasoconstrictive and vasodilatory reactivity in chronically hypoperfused territories adjacent to AVMs such that pharmacological or metabolic stimuli may induce further vasodilation, but sudden redistribution of large volumes of flow will not promote protective vasoconstriction.

Aged↗
PubMed1988

Use of etomidate, temporary arterial occlusion, and intraoperative angiography in surgical treatment of large and giant cerebral aneurysms.

The operative management of large and giant aneurysms is complicated by their typically atheromatous and thick walls, frequent intramural thrombosis with calcification, and broad-based necks that often incorporate perforating and other vital vessels. Not infrequently, it is necessary to at least focally arrest the intracranial circulation and open or excise these aneurysms to facilitate vascular reconstruction. This maneuver, in patients whose disease processes have destroyed autoregulatory function or who have inadequate sources of anatomical collateral supply, may cause the threshold for permanent ischemic injury to be exceeded. The authors have recently treated 14 such patients while under electroencephalographic monitoring to document electrical burst suppression induced by the administration of etomidate, followed by temporary clipping to permit vascular repair and intraoperative angiography to document patency of parent arteries. Up to 60 minutes of internal carotid artery occlusion, 35 minutes of middle cerebral artery occlusion, 19 minutes of upper basilar artery occlusion, and 4 1/2 minutes of lower basilar artery occlusion have been well tolerated using this protocol. In such situations, etomidate may be effective in protecting the cerebral circulation without the detrimental cardiotoxicity observed with protective doses of barbiturates.

Adult↗
PubMed1985

Use of the extracranial-intracranial arterial bypass in the management of refractory vasospasm: a case report.

Cerebral arterial vasospasm after aneurysmal subarachnoid hemorrhage remains one of the major causes of morbidity and mortality in patients surviving the initial hemorrhage. Once established, no known method has been shown to reverse this process in humans. Although intravascular volume expansion and induced arterial hypertension have been shown to be effective in the reversal of neurological deficits secondary to vasospasm, a large proportion of patients remain refractory to these methods. We report one such case successfully managed by the establishment of an extracranial-intracranial anastomosis in an attempt to augment collateral flow.

Adult↗
PubMed1985

Resection of upper aerodigestive tract tumors involving the middle cranial fossa.

Benign and malignant neoplasms of the upper aerodigestive tract that invade the middle cranial fossa are frequently considered unresectable due to the proximity of the cavernous sinus and internal artery, and to the inaccessibility of this region via conventional surgical approaches. We report our experience using a combined, lateral intracranial and infratemporal fossa procedure for the management of these tumors in four patients. Successful removal of neoplasm associated with minimal morbidity was accomplished in 3 patients, 2 with angiofibromas and 1 with an adenoid cystic carcinoma. The postoperative course of the fourth patient was complicated by meningitis which resulted in the patient's death five months following resection of an adenocarcinoma.

Adolescent↗
PubMed1981

Saphenous vein interposition grafts in the microsurgical treatment of cerebral ischemia.

Saphenous vein interposition grafts of varying lengths have been used in 25 extracranial-intracranial bypasses since 1974. Indications for operation included transient ischemic episodes (13 cases), prophylactic augmentation of middle cerebral artery (MCA) collateral flow prior to surgical treatment of intracranial aneurysm (four), and traumatic occlusion of cervical or intracranial internal carotid arteries (eight). Vein grafts to cortical branches of MCA originated from superficial temporal or occipital arteries in ten cases, common or external carotid arteries in ten, and subclavian or innominate vessels in five. Twenty-one patients have been followed up for a minimum of 12 months. Immediate patency rate was 84%; one late graft occlusion decreased overall patency to 80%. There was one operative mortality. Early technical problems, including donor-recipient size disparity, anastomotic distortion, and inappropriate graft routing, have been overcome by the use of 2-mm veins, the avoidance of hydrostatic dilation, and the construction of retroauricular tunnels. It is reasonable to assume that long-term patency of these reconstructions will parallel that of extracranial-intracranial bypasses using autologous arteries.

Arterial Occlusive Diseases↗
PubMed1980

Management of penetrating injuries of the internal carotid artery at the base of the skull utilizing extracranial-intracranial bypass.

Penetrating injuries of the internal carotid artery at the base of the skull often require permanent or transient occlusion of the injured vessel during repair. Extracranial-intracranial bypass (EC-IC) was employed in five patients to insure adequate cerebral perfusion during cervical exploration. Preoperative neurologic deficits were noted in three patients; two demonstrated complete reversal following EC-IC. This experience suggests that EC-IC can maintain adequate cerebral perfusion during repair of internal carotid injuries and allow selective revascularization of patients with neurologic deficit and carotid occlusion.

Adult↗
PubMed1980

Failure of extracranial-intracranial arterial bypass in acute middle cerebral artery occlusion: case report.

Extracranial-intracranial arterial bypass procedures provide important augmentation of collateral circulation to cortical areas rendered potentially ischemic by therapeutic occlusion of major branches of the circle of Willis. Although the case studies reported to date in general reflect positively on this use of the bypass procedure, this report of a patient who failed to tolerate acute middle cerebral artery occlusion despite the presence of a patent superficial temporal-middle cerebral artery branch anastomosis points up several of the practical and theoretical limitations of this therapeutic approach. Certain modifications of the timing of the bypass procedure, the selection of donor and recipient arteries, and the mechanics of intracranial arterial occlusion may allow a wider application of extracranial-intracranial arterial bypass in this therapeutic setting.

Acute Disease↗
PubMed1980

Traumatic middle cerebral artery aneurysm: case report.

A case of traumatic middle cerebral artery aneurysm is presented. The case demonstrates some of the difficulties encountered when dealing with this type of aneurysm. The unusual surgical approach required for obliteration is described.

Adult↗
PubMed1979

Microsurgical treatment of transient cerebral ischemia. Preliminary results in 50 patients.

Extracranial-intracranial arterial bypass is a microneurosurgical procedure recently introduced in the treatment of a variety of cerebrovascular ischemic states. Fifty patients with transient ischemic attacks (TIAs) localized to the distribution of the internal carotid artery underwent this procedure during a 48-month period. All have been followed up for at least 14 months after surgery. There were no operative deaths, and notable postoperative morbidity has been experienced in less than 8% of cases. Seventy-six percent of patients have been asymptomatic since surgery, 14% have continued to experience TIAs, and 6% have had completed strokes (2% occurring in the operative hemisphere).

Adult↗
PubMed1979

Risk of intracranial aneurysm surgery in the good grade patient: early versus late operation.

To evaluate the risk of definitive intracranial microsurgical aneurysm obliteration as a function of the timing of the operative intervention, we retrospectively reviewed 106 consecutive patients in good clinical condition who underwent such surgery. The patients who were operated upon within the first 8 days of their most recent subarachnoid hemorrhage formed the "early" group; the patients operated upon between the 9th and 31st day were considered to have undergone "late" surgery. On the basis of their clinical outcome the patients were allocated to one of four outcome categories ("good," "fair," "death") both at the time of their hospital discharge and at their most recent clinical re-evaluation, a minimum of 6 months after discharge from the hospital. There was no significant difference in the operative mortality in each group (early surgery, 5%; late surgery, 4%); additionally, no significant difference was noted in the incidence of either intraoperative complications or postoperative morbidity. A suggestive but statistically insignificant increase in the incidence of postoperative cerebral ischemic events was seen in the "early" surgery group (8% vs. 4% for the "late" surgery group). The potential significance of these findings for the timing of intracranial aneurysm surgery is discussed.

Brain Ischemia↗
PubMedDate not supplied

Microsurgical evaluation of the pterional approach to aneurysms of the distal basilar circulation.

The microsurgical correlates the pterional approach to the distal basilar circulation were evaluated in 20 cases of posterior circulation aneurysms, 50 human cadaver dissections, and a variety of other intracranial surgical lesions. The pterional approach permitted successful clipping of the aneurysm in 13 of 15 basilar bifurcation aneurysms, 1 of 2 basilar-posterior cerebral aneurysms, and 2 of 3 basilar-superior cerebellar aneurysms. In each of the failed attempts via the pterional approach, the subtemporal route ultimately resulted in proper clip application. The interposition of the posterior clinoid process was the impediment to successful clipping in three of the four cases that could not be managed via the pterional approach. All 3 of these patients had a basilar bifurcation that was below the level of the posterior clinoid on angiography, whereas none of the remaining 17 aneurysm patients demonstrated a low-lying bifurcation. Posterior displacement of the basilar artery away from the posterior clinoid exceeded 1 cm in only 13% of our cases and was not an impediment to successful clipping of the aneurysm via the pterional route. We conclude that, when the anatomical situation is appropriate, the pterional approach offers the advantages of less brain retraction and better visualization of the parent arteries and important perforating branches when compared to the subtemporal approach.

Basilar Artery↗