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Biomedical subjects

H H Batjer

Publications and source records attributed to H H Batjer.

At least 37 records · Page 2Linked to original sources
PubMed1996

External carotid-to-middle cerebral bypass in the treatment of complex internal carotid injury.

Patients with penetrating carotid injuries above C2 present special challenges to the cerebrovascular surgeon. A subgroup of patients may lack the vascular collaterals necessary to tolerate carotid sacrifice or prolonged ischemia during direct carotid repair. We present a technique of extracranial-intracranial (EC-IC) saphenous vein bypass in two patients with high cervical and skull base carotid injuries and poor vascular collaterals. This technique allows preservation of internal carotid flow during the proximal anastomosis. Interruption of cerebral blood flow is limited to the duration required for a distal intracranial anastomosis and is confined to the territory supplied by a single middle cerebral branch. The procedure eliminates systemic anticoagulation, includes trapping of the injured segment of the internal carotid artery, and restores a volume of flow similar to that of the internal carotid artery. It is a valuable adjunct in this specific population of patients with high carotid injuries who cannot tolerate even brief periods of temporary occlusion or in whom clinical urgency precludes an endovascular trial occlusion.

Adult↗
PubMed1996

Middle cerebral artery occlusion after pterional approach to basilar bifurcation aneurysm: technical case report.

OBJECTIVE AND IMPORTANCE: The authors present a case of a subacute middle cerebral artery occlusion that was sustained subsequent to a basilar apex aneurysm clipping via the pterional approach. A middle cerebral artery stroke is a rare complication of basilar bifurcation aneurysm clipping, and, to our knowledge, this complication has not been previously described in otherwise healthy patients with unruptured basilar aneurysms. CLINICAL PRESENTATION: A 36-year-old woman was found to have an unruptured 1.6 x 1.0-cm basilar tip aneurysm, as revealed by computed tomography. She elected to undergo surgical repair. TECHNIQUE: Transsylvian dissection, exposure, and uneventful clipping of the basilar bifurcation aneurysm were performed. CONCLUSIONS: A middle cerebral artery stroke occurring after the repair of an intact basilar aneurysm has several possible causes, including retraction injury and direct surgical injury. Awareness of this complication is important for the early recognition and management of the occlusion before infarction is established.

Adult↗
PubMed1995

Elevated transcranial Doppler ultrasound velocities following therapeutic arterial dilation.

BACKGROUND: Elevated transcranial Doppler (TCD) velocities seen after cerebral angioplasty are commonly interpreted as evidence of residual or recurrent stenosis but may conceivably arise from hyperemia and require different clinical management. SUMMARY OF REPORT: Four cases of abnormally elevated mean TCD velocities obtained after therapeutic arterial dilation with either balloon angioplasty or intra-arterial administration of papaverine are described. In each case, cerebral angiography revealed a dilated vessel, suggesting that hyperemia and impaired autoregulation were the causes of the high velocities. CONCLUSIONS: These examples suggest that high TCD velocities after vessel dilation may be produced by unpredictable amounts of vessel narrowing and flow alteration. Although a normalizing TCD velocity after angioplasty suggests effective vessel dilation, high velocities may be due partly to hyperemia and cannot be interpreted as arising solely from recurrent stenosis.

Adult↗
PubMed1995

Intravenous perflubron emulsion administration improves the recovery of auditory evoked potentials after temporary brain stem ischemia in dogs.

Oxygent, a second-generation perfluorocarbon (Perflubron) emulsion (Alliance Pharmaceutical Corporation, San Diego, CA) with superior oxygen delivery characteristics and greater stability than previous perfluorocarbon emulsions, was evaluated as a cerebroprotective agent in a dog model of partial brain stem ischemia. Six dogs were exposed to 20 minutes of isolated brain stem ischemia after receiving an intravenous bolus of Oxygent at a dose of 1.5 ml/kg. Brain stem auditory evoked potentials (BAEP) and regional cerebral blood flow were measured before and during the ischemia and for 5 hours after reperfusion. Changes in BAEP in this group were compared with those in four control dogs that experienced an identical ischemic period but that did not receive Oxygent. During the ischemic period, both control and Oxygent-treated animals experienced a dramatic decline in BAEP to under 10% of the baseline value. After reperfusion, the BAEP increased in both groups to between 50 and 70% of the baseline. In the Oxygent-treated group, the BAEP continued to recover to a final sustained level of over 80% of baseline. In contrast, the control animals suffered a drop in BAEP to 23% of baseline after the brief postischemic peak. The continued improvement in the BAEP in the Oxygent-treated group compared with the control groups suggests that Oxygent may be of some value as a protective agent to the brain stem during ischemia. This effect may be the result of improved oxygen delivery to the brain stem or may be related to other effects of Oxygent, such as reduction of reperfusion injury. Results suggest that Oxygent may be useful as a cerebroprotectant during cerebrovascular surgeries that require temporarily reducing blood flow to the brain stem.

Animals↗
PubMed1995

A case of acute vertigo with incidental aneurysms.

It is essential to decrease the risk to the patient to an absolute minimum when prophylactic procedures are offered against a relatively unpredictable (for the individual patient) natural history risk. Very careful preoperative planning and intraoperative execution are mandatory to maximize the chances of the patient for a successful outcome.

Basilar Artery↗
PubMed1995

A canine model of acute hindbrain ischemia and reperfusion.

Animal models of brain stem ischemia are needed for pathophysiological study and evaluation of treatment; few such models are available currently. A new canine model of hindbrain ischemia and reperfusion is introduced in this article. Through an anterior cervical approach, the basilar artery was surgically exposed in 18 dogs. The posterior communicating and superior cerebellar arteries were embolized with cyanoacrylate glue to isolate the posterior circulation from the anterior circulation. Reversible hindbrain ischemia was induced in 14 dogs by the temporary clipping of the vertebral and ventral spinal arteries for various periods (10-30 min), then the clips were removed and reperfusion was achieved for 5 hours. In all 14 dogs, the hindbrain ischemia was confirmed by the decreased perfusion pressure in the basilar artery (< 10 mm Hg), the diminished regional cerebral blood flow as measured with a laser Doppler flowmeter at the medulla oblongata (< 10 ml/100 g/min), the flattened brain stem auditory evoked potentials, and the increased leakage of Evans blue dye from tissue. These parameters did not change in the four control dogs. The changes in brain stem auditory evoked potentials were closely related to the length of ischemic interval; after 10 minutes of ischemia, reperfusion fully reversed the changes in brain stem auditory evoked potentials, but 20-minute and 30-minute ischemic intervals partially or totally depleted the brain stem auditory evoked potentials. Delayed postischemic hypoperfusion occurred in all five dogs that underwent the 30-minute ischemic interval. The early physiological changes in this model allowed us to estimate the severity of brain stem ischemia and the resulting damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

The protective effects of thiopental on brain stem ischemia.

Thiopental, a barbiturate anesthetic, which at high doses suppresses cortical electroencephalogram activity, was evaluated as a neuroprotective agent in a dog model of reversible, hindbrain ischemia. Fourteen dogs were exposed to 20 minutes of isolated brain stem ischemia after pretreatment with 35 mg per kg of thiopental or placebo. Brain stem auditory evoked potentials (BAEPs) and regional cerebral blood flow were measured before and during the ischemia and for 5 hours after reperfusion. During the ischemic period, both control and thiopental-treated animals experienced dramatic declines in the BAEPs to less than 10% of baseline. On reperfusion for 30 minutes, the BAEPs increased in both groups to near 40% of baseline. In the thiopental-treated animals, the BAEPs continued to recover variably to a mean of 70% of baseline by 5 hours of reperfusion. In contrast, untreated animals showed a decline in BAEPs after 30 minutes of reperfusion. The improved recovery of BAEPs in the thiopental-treated animals suggests that thiopental may be of some value as a cerebroprotective agent, although the mechanism remains unclear. The variability in recovery in this group implies that other factors play a significant role in mediating functional recovery from ischemic brain stem damage.

Anesthetics, Intravenous↗
PubMed1995

Limited protective effects of etomidate during brainstem ischemia in dogs.

To evaluate etomidate as a neuroprotective agent in the brain stem, 33 dogs were divided into seven groups and were exposed to isolated, reversible brainstem ischemia in the presence or absence of etomidate using a newly developed canine model of brainstem ischemia. Brainstem auditory evoked potentials (BAEP) and regional cerebral blood flow were measured during ischemia and for 5 hours after reperfusion. This model provides a potential physiological environment in which to test the efficacy of putative brainstem ischemic protective strategies. During ischemia, BAEP were abolished in all animals. Without etomidate 10 minutes of ischemia was of short enough duration to allow complete recovery of BAEP. Ischemia of 20 or 30 minutes' duration resulted in minimal recovery. The dose of etomidate administered did not suppress BAEP or brainstem cardiovascular response to ischemia. In animals receiving etomidate and rendered ischemic for 20 minutes, a significant but only temporary recovery in BAEP was seen. Etomidate failed to have a significant effect in animals rendered ischemic for 30 minutes. The minimal effect of etomidate on the current measures of brainstem function is in contrast to etomidate's known suppressive effect on cortical electroencephalogram and predicts that etomidate does little to alter brainstem metabolism. Etomidate's failure to provide for permanent recovery of BAEP suggests that the drug does not give sufficient protection from ischemia to the brainstem neurons in the auditory pathway. If these auditory neurons reflect brainstem function as a whole, etomidate may not be the protective agent of choice during temporary arterial occlusion of posterior circulation.

Animals↗
PubMed1994

Combined transsylvian-subtemporal exposure of cerebral aneurysms involving the basilar apex.

The surgical repair of cerebral aneurysms involving the apex of the basilar artery continues to undergo refinement and evolution. The inherent difficulty in accessing the basilar apex as well as the complexities of the microanatomy render this area a notoriously hazardous and technically challenging region in which to perform microsurgical clipping of cerebral aneurysms. Several operative approaches have been described and are constantly undergoing a state of evolution in the hopes of optimizing the exposure of the distal basilar artery and minimizing the inherent risks of surgery. The consistent decline in operative morbidity has paralleled improved understanding of the microvascular anatomy, both in this region and along the various corridors of approach. No single operative approach is universally superior, considering the wide variability of individual patient anatomy and vascular configurations. Each approach has strengths, weaknesses, and potential complications that must be considered in the though process of planning an operative attack on a basilar apex aneurysm. Intimate familiarity with the microvasculature and the microsurgical anatomy of the region is an imperative prerequisite for the application of any surgical approach to this region. This paper outlines a detailed review of the microsurgical anatomy that is pertinent to microsurgery of aneurysms in this region, and describes an approach referred to as the combined transsylvian-subtemporal approach. We have found this operative approach particularly useful in aneurysm surgery of the basilar apex but do not mean to imply that this single approach is suitable for all surgeons or all patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Basilar Artery↗
PubMed1994

An unusual transcranial Doppler waveform associated with vessel distortion in giant intracranial aneurysms.

Although the shapes of velocity waveforms obtained with transcranial Doppler examination can indicate such abnormalities as increased intracranial pressure and proximal arterial compromise, the significance of unusual waveform morphologies is often obscure. In this report, we describe four cases in which an unusual waveform morphology was obtained from vessels distorted and narrowed by intracranial masses. The appearance of this unusual morphology as an isolated signal within a transcranial Doppler examination should, therefore, suggest a structural deformation of the insonated vessel to those who interpret transcranial Doppler studies.

Adult↗
PubMed1994

Interdisciplinary evaluation of cerebral hemodynamics in the treatment of arteriovenous fistulae associated with giant varices.

The techniques for the treatment of intracranial arteriovenous fistulae include angiographic balloon occlusion of the fistula as well as direct surgical attack. Regardless of the method, the occurrence of severe hyperemia caused by a lack of autoregulation after obliteration of the fistula remains a significant concern. We report the use of single photon emission computed tomography and transcranial Doppler studies to assess the occurrence of hyperemia during trial balloon occlusion of such fistulae in two patients. Single photon emission computed tomography and transcranial Doppler studies confirmed the lack of hyperemia during the test occlusion, allowing consideration of treatment plans involving acute fistula occlusion without the difficulty imposed by gradual occlusion and permitting a more accurate evaluation of risk. The purpose of this report is to illustrate how clinical evaluation of intracranial hemodynamics can contribute significantly to treatment decisions.

Adult↗
PubMed1994

Surgery for paraclinoidal carotid artery aneurysms.

Aneurysms arising from the proximal carotid artery between the roof of the cavernous sinus and the origin of the posterior communicating artery pose conceptual and technical surgical problems with regard to acquisition of proximal control and safe intracranial exposure. Over the past 3 1/2 years, 89 patients with paraclinoidal aneurysms have been treated at the University of Texas Southwestern Medical Center. Thirty-nine (44%) of these patients presented with subarachnoid hemorrhage. A total of 149 aneurysms and six arteriovenous malformations have been identified in this patient group such that 38 (43%) of the patients suffered multiple vascular anomalies. Temporary artery occlusion has been employed during operation in 48 cases (54%), permanent carotid artery occlusion in four (4%), and hypothermic circulatory arrest in two (2%). Twenty-two patients harbored giant aneurysms, seven of which had ruptured. Outcome was considered good in 77 patients (86.5%), fair in eight (9%), and poor in three (3%); one patient died. This concentrated experience permitted a practical anatomical grouping of aneurysms into three types: carotid-ophthalmic artery aneurysms with a superior or superomedial projection (44 cases); superior hypophyseal aneurysms with a medial or inferomedial projection (26 cases); and proximal posterior carotid artery wall aneurysms projecting posteriorly or posterolaterally (19 cases). Despite the fact that paraclinoidal aneurysms often disobey the traditional teachings of aneurysm development, having no vessel of origin or clear hemodynamic cause, this practical grouping has allowed individualized and focused operative approaches unique to each aneurysm projection with good visual function and outcome in most patients.

Carotid Artery Diseases↗
PubMed1994

A clinical study of the parameters and effects of temporary arterial occlusion in the management of intracranial aneurysms.

Temporary occlusion of intracranial arteries has emerged as a valuable technical adjunct in the management of intracranial aneurysms. The current study considered 121 patients (from a group of 234 consecutive aneurysm patients treated during a 2-yr period) who underwent elective temporary arterial occlusion. Twenty-one patients were excluded from further study because of an intraoperative rupture of an aneurysm, the elective sacrifice of afferent or efferent vessels, or the performance of an extracranial-intracranial arterial bypass graft; the remaining 100 patients underwent elective temporary occlusion under a standard neuroanesthetic regimen, including etomidate-induced burst suppression, normotension, normovolemia, and normothermia. In the postoperative period, radiographic evidence of ischemic brain injury in the distribution of the arteries occluded was selected as the end point for the failure of occlusion tolerance. The parameters evaluated with respect to this end point included the duration and nature of the temporary arterial occlusion, the number of the occlusive episodes, the specific vascular territory occluded, patient age, neurological status, presence of subarachnoid hemorrhage, vasospasm, and aneurysm size. Several parameters were found to be related to the postoperative development of ischemic injury. Patients more than 61 years of age and those in poor neurological condition (Hunt and Hess Grades III to IV) did not tolerate temporary occlusion as well as patients who were younger and in better condition. Patients occluded for less than 14 minutes routinely tolerated the iatrogenic ischemia; the 95% confidence level for the toleration of occlusion without the development of infarction occurred at 19 minutes. All patients occluded for more than 31 minutes had both clinical and radiographic evidence of cerebral infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Effects of etomidate and hypothermia on cerebral metabolism and blood flow in a canine model of hypoperfusion.

Etomidate is a nonbarbiturate hypnotic agent which, like the barbiturates, decreases the cerebral metabolic rate of oxygen consumption (CMRO2) 35-50%. The present studies assessed whether etomidate decreased CMRO2 through temperature-dependent mechanisms and whether the combination of etomidate and moderate hypothermia (28 degrees C) decreased CMRO2 more than hypothermia alone. Nineteen anesthetized dogs were treated with saline, etomidate (burst-suppressive doses), etomidate with hypothermia, or hypothermia alone. Etomidate did not affect (p > 0.05) the mean arterial pressure (MAP, mm Hg) but modestly lowered the heart rate [HR; 124 +/- 6 to 105 +/- 14, (mean +/- SEM); p < 0.05] whereas hypothermia (without or with etomidate) lowered (p < 0.05) both MAP (141 +/- 4 to 116 +/- 5 and 135 +/- 6 to 81 +/- 7) and HR (135 +/- 14 to 84 +/- 3 and 135 +/- 10 to 69 +/- 5, respectively). Etomidate administration did not result in a change (p > 0.05) in the esophageal, brain parenchymal, or subdural temperature. CMRO2 (ml/100 g/min) decreased (p < 0.05) during etomidate administration (3.2 +/- 0.4 to 1.7 +/- 0.2) and hypothermia (3.5 +/- 0.2 to 1.1 +/- 0.2), but the addition of etomidate to hypothermia did not further reduce CMRO2 in the animals (3.1 +/- 0.5 to 1.3 +/- 0.2) despite decreasing their brain hemispheric electrical activity from 9 +/- 1 Hz to a burst-suppressive state.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗