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Biomedical subjects

R F Spetzler

Publications and source records attributed to R F Spetzler.

At least 163 records · Page 9Linked to original sources
PubMed1992

Relationship of perfusion pressure and size to risk of hemorrhage from arteriovenous malformations.

The relationship between the size of an arteriovenous malformation (AVM) and its propensity to hemorrhage is unclear. Although nidus volume increases geometrically with respect to AVM diameter, hemorrhages are at least as common, in small AVM's compared to large AVM's. The authors prospectively evaluated 92 AVM's for nidus size, hematoma size, and arterial feeding pressure to determine if these variables influence the tendency to hemorrhage. Small AVM's (diameter less than or equal to 3 cm) presented with hemorrhage significantly more often (p less than 0.001) than large AVM's (diameter greater than 6 cm), the incidence being 82% versus 21%. Intraoperative arterial pressures were recorded from the main feeding vessel(s) in 24 of the 92 patients in this series: 10 presented with hemorrhage and 14 presented with other neurological symptoms. In the AVM's that had hemorrhaged, the mean difference between mean arterial blood pressure and the feeding artery pressure was 6.5 mm Hg (range 2 to 15 mm Hg). In the AVM's that did not rupture, this difference was 40 mm Hg (range 17 to 63 mm Hg). Smaller AVM's had significantly higher feeding artery pressures (p less than 0.05) than did larger AVM's, and they were associated with large hemorrhages. It is suggested that differences in arterial feeding pressure may be responsible for the observed relationship between the size of AVM's and the frequency and severity of hemorrhage.

Adolescent↗
PubMed1991

Cardiocirculatory arrest with hypothermia. Experimental study.

Direct surgical attack on intracranial malformations of great complexity may be facilitated by complete cardiocirculatory arrest under hypothermia. To improve the technical aspects of this procedure and to determine the optimum depth of hypothermia, the duration of arrest that can be tolerated, and the role of barbiturate brain protection, we conducted an experimental study on 11 baboons. Arrest lasted for 45 or 90 minutes at a brain temperature of 12 degrees C. The animals were assessed by clinical, neuroradiological and necropsy examination. All 4 animals subjected to 45 minutes arrest made a good clinical recovery while 3 of the 7 subjected to 90 minutes arrest presented thromboembolic complications. Strict heparinization in the last 2 animals solved these problems. The findings of this study may help to make the procedure safer for clinical use.

Animals↗
PubMed1991

Continuous postoperative monitoring of cortical blood flow and intracranial pressure.

A new technique to continuously monitor cortical blood flow and intracranial pressure in postoperative patients is described. A thermal diffusion flow probe with a pressure port is left in contact with the cortex at craniotomy. Postoperative intracranial pressure--cortical blood flow can be monitored and acute changes or trends are readily detected. The thermal flow probe has been previously compared with radioactive xenon (133Xe) clearance and hydrogen clearance methods of measuring cortical blood flow in animals. The technique gives a real-time quantitative indication of flow. Changes in cortical blood flow can be observed within a few seconds and the effects of treatment can be readily observed. Changes in flow due to vasospasm have been demonstrated in subarachnoid hemorrhage. It is anticipated that information learned from this method will aid in the management of patients with head trauma, tumors, and subarachnoid hemorrhage.

Brain↗
PubMed1991

Combined approach for lesions involving the cerebellopontine angle and skull base: experience with 30 cases.

This article presents a series of 30 patients who underwent a combination of the subtemporal and posterior fossa approaches for exposure of lesions in the clivus or medial petrous region. This combined supra- and infratentorial approach is divided into three variations with progressively greater petrous bone resection to increase exposure of the clivus and medial petrous region. The approach has been divided into petrous bone resection with preservation of hearing (retrolabyrinthine), greater petrous bone resection with sacrifice of hearing (translabyrinthine), and finally maximum petrous drilling with sacrifice of hearing along with transposition of the facial nerve (transcochlear). Ninety-three percent of the cases returned to their premorbid occupations.

Journal Article↗
PubMed1991

Failure of transluminal angioplasty in the treatment of myointimal hyperplasia of the internal carotid artery: case report.

Recurrent stenosis of the carotid arteries after a carotid endarterectomy for atherosclerosis can occur as a result of myointimal hyperplasia. This condition was treated by percutaneous transluminal angioplasty. Excellent dilatation of the vessel lumen was documented after balloon dilatation. A 6-month follow-up angiographic study, however, demonstrated recurrent high-grade stenosis at the same level in both carotid arteries. Presumably, the failure of percutaneous transluminal angioplasty and the treatment of myointimal hyperplasia of the internal carotid artery results in the same condition after the original endarterectomy, that is, additional myointimal hyperplasia.

Angioplasty, Balloon↗
PubMed1991

Traumatic atlantooccipital dislocation with survival.

Survival after traumatic atlantooccipital dislocation is rare. Only long-term survivors have been reported in the literature; however, improved prehospital care is likely responsible for the increase in the number of these patients seen at neurotrauma centers over the last decade. Associated severe and persistent neurological deficits are common in the few survivors. We report the case of a 10-year-old boy with traumatic atlantooccipital dislocation and a severe neurological injury. Low-field magnetic resonance imaging provided the additional diagnosis of an associated cervicomedullary epidural hematoma. The patient underwent emergency operative evacuation of the hematoma and an occipital-cervical fusion with internal fixation. He had a remarkable recovery in neurological function and achieved stable bony fusion 3 months postoperatively. With early recognition of this entity, improved neuroradiological imaging techniques, and aggressive treatment, patients may survive with significant neurological recovery.

Atlanto-Occipital Joint↗
PubMed1991

Combined approach for lesions involving the cerebellopontine angle and skull base: experience with 20 cases--preliminary report.

Skull base tumors involving the clivus, petrous bone, and adjacent areas can be formidable lesions to successfully remove without causing significant neurologic deficits. At our institution in the last 5 years, twenty patients out of 103 patients with skull base tumors have undergone the supratentorial-infratentorial combined approach for removal of a neoplasm (nine schwannomas, six meningiomas, two epidermoids, one extensive basal cell carcinoma, one pontine cavernous malformation, and one basilar artery aneurysm). The average patient age was 43 years. The combined approaches in conjunction with the subtemporal exposure were retrosigmoid-retrolabyrinthine, retrosigmoid-translabyrinthine, or retrosigmoid-transcochlear. The choice depended upon the type and location of the lesion and the deficits noted preoperatively. Basically, the approach allowed communication of the middle fossa and posterior fossa by totally dividing the tentorium as much as necessary for effective surgical manipulations. Both sigmoid and superior petrosal sinuses are divided. There were no deaths. Postoperative neurologic deficits included temporary seventh nerve paralysis, sixth nerve weakness, fifth nerve sensory deficits, cerebrospinal fluid leaks, and hydrocephalus requiring a shunt. Overall, the results were very gratifying, considering the difficulties encountered in the surgical removal of these lesions.

Adult↗
PubMed1991

Anterolateral transthoracic transvertebral resection of an intramedullary spinal arteriovenous malformation. Case report.

The case is reported of a 16-year-old girl with an anterior thoracic spinal cord arteriovenous malformation (AVM) who presented with subarachnoid hemorrhage and sudden change in lower-extremity strength. Spinal angiography revealed a Type II (glomus) intramedullary AVM at the T7-8 level fed by multiple branches of the anterior spinal artery. The AVM was successfully resected using an anterolateral transthoracic approach. The details of this approach and its use for surgery of anterior thoracic spine lesions are described.

Adolescent↗
PubMed1991

Cavernous malformations of the brain stem.

Once they become symptomatic, cavernous malformations of the brain stem appear to cause progressive morbidity from repetitive hemorrhage, and can even be fatal. Twenty-four patients with long-tract and/or cranial nerve findings from their cavernous malformations of the brain stem were seen for initial evaluation or surgical consultation and thereafter received either surgical or continued conservative treatment. The decision to operate was based on the proximity of the cavernous malformation to the pial surface of the brain stem, the patient's neurological status, and the number of symptomatic episodes. Sixteen patients were treated by definitive surgery directed at excision of their malformation. In four patients, associated venous malformations influenced the surgical approach and their recognition avoided the risk of inappropriate excision of the venous malformation. Although some of the 16 patients had transient, immediate, postoperative worsening of their neurological deficits, the outcome of all except one was the same or improved. Only one patient developed recurrent symptoms: a new deficit 2 1/2 years after surgery required reoperation after regrowth of the cavernous malformation. She has been neurologically stable since the second surgery. One patient died 6 months postoperatively from a shunt infection and sepsis. The eight conservatively treated patients are followed with annual magnetic resonance imaging studies. One has a dramatic associated venous malformation. Seven patients have either minor intermittent or no symptoms, and the eighth died from a hemorrhage 1 year after his initial presentation. Based on these results, surgical extirpation of symptomatic cavernous malformations of the brain stem appears to be the treatment of choice when a patient is symptomatic, the lesion is located superficially, and an operative approach can spare eloquent tissue. When cavernous malformations of the brain stem are completely excised, cure appears permanent.

Adult↗
PubMed1991

Phase I trial of tissue plasminogen activator for the prevention of vasospasm in patients with aneurysmal subarachnoid hemorrhage.

Recent laboratory studies have demonstrated that intracisternal administration of recombinant tissue plasminogen activator (rt-PA) can facilitate the normal clearing of blood from the subarachnoid space and prevent or ameliorate delayed arterial spasm. The results of a preliminary Phase I trial of intracisternal rt-PA in 10 patients are reported with documented aneurysmal subarachnoid hemorrhage (SAH). All patients enrolled were classified as clinical Grade III or IV (according to Hunt and Hess) with thick clots or layers of blood in the basal cisterns and major cerebral fissures (Fisher Grade 3). Ventriculostomy and surgery for clipping of the aneurysms were performed within 48 hours of hemorrhage. In one patient, 10 mg rt-PA was instilled into the subarachnoid cisterns prior to closing the dura. In the remaining nine patients, a small silicone catheter was left in the subarachnoid space and rt-PA (5 mg in four cases or 1.5 mg (0.5 mg every 8 hours for three infusions) in five cases) was instilled 12 to 24 hours after surgery. Minor local bleeding complications were noted in all patients receiving 5 or 10 mg rt-PA. Oozing was noted at the operative incision site in four of five patients and at the ventriculostomy site in two patients. One patient developed a small epidural hematoma that was treated by delayed drainage. No bleeding complications were noted in the patients receiving the lower regimen of rt-PA (three infusions of 0.5 mg each). Serial coagulation studies demonstrated no evidence of systemic fibrinolysis. Analysis of cisternal cerebrospinal fluid samples revealed thrombolytic tissue plasminogen activator (t-PA) levels for 24 to 48 hours. Follow-up cerebral angiography 7 to 8 days after rupture disclosed mild to moderate spasm in nine patients, while one patient with hemorrhage from a posterior inferior cerebellar artery aneurysm had severe focal spasm of the vertebral arteries that was not symptomatic. These results suggest that postoperative treatment with rt-PA may be effective in reducing the severity of delayed cerebral vasospasm. The results of serial t-PA levels suggest that the lower dosage regimen with divided dosages at 8-hour intervals is well tolerated and that even lower dosages may be effective. Further studies are clearly indicated.

Adult↗
PubMed1991

Cavernous malformations and capillary telangiectasia: a spectrum within a single pathological entity.

Cerebral vascular malformations have traditionally been divided into four categories: arteriovenous, venous, cavernous, and capillary telangiectases. A controversy exists about separating the latter two lesions into separate entities. Critics claim the distinction is arbitrary but have been unable to present convincing evidence linking the two types of lesions. We have reviewed the histories of 20 patients with cavernous malformations and have analyzed the clinical, radiographic, and surgical-autopsy data associated with these lesions. In some patients, multiple lesions, including cavernous malformations, capillary telangiectases, and transitional forms between the two, were identified. Based on this analysis, we conclude that capillary telangiectasia and cavernous malformations represent two pathological extremes within the same vascular malformation category and propose grouping them as a single cerebral entity called cerebral capillary malformations.

Capillaries↗
PubMed1991

Management of anterior skull base tumors.

A team approach is necessary to remove tumors involving cranial and facial structures. The combined talents of the appropriate specialists have allowed aggressive and successful removal of large and complicated tumors. Vascular reconstruction, free vascularized pedicle grafts, transfacial exposure combined with classic neurosurgical exposure have provided a new era for successful surgery of the frontal fossa of the cranium.

Adult↗
PubMed1990

Postoperative monitoring of cerebral blood flow in patients harboring intracranial aneurysms.

Fifteen patients harbouring intracranial aneurysms were monitored postoperatively. A thermal diffusion flow probe was placed on the cortex, in an area of interest, and continuous recording of cerebral blood flow (CBF) was carried out for 1-4 days. Vasospasm can also be detected by clinical deterioration, increased velocity by transcranial Doppler, and by angiographical evidence of decrease in vessel calibre. A comparison was made between these methods of determining vasospasm and changes in CBF. Three patients had unruptured aneurysms and no evidence of vasospasm. These patients had a range of CBF from 44 to 100 cc 100 g-1 min-1 with a daily mean of 78 cc 100 g-1 min-1. One patient was operated on, in a delayed fashion, after a period of vasospasm on post-subarachnoid haemorrhage (SAH) Day 18 and was found to have a CBF of 40 cc 100 g-1 min-1 when the pCO2 was 21 Torr and the mean blood pressure (BP) was 99 Torr. The development of vasospasm was correlated with a CBF of less than 40 cc 100 g-1 min-1. Some patients with vasospasm also develop a significant drop in CBF during the period of monitoring. Using these criteria, CBF monitoring predicted the development of vasospasm in seven patients, was compatible with the clinical course in three patients and was misleading in two patients. In the seven patients in which CBF predicted vasospasm, changes were seen in CBF prior to changes observed by clinical examination, transcranial Doppler, and/or angiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral Angiography↗