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Biomedical subjects

J M Zabramski

Publications and source records attributed to J M Zabramski.

At least 73 records · Page 4Linked to original sources
PubMed1991

Pediatric spinal cord injury without radiographic abnormalities: report of 26 cases and review of the literature.

Spinal cord injury without radiographic abnormality (SCIWORA) occurs primarily in the pediatric population but is less common than other forms of spinal injury among children. Between 1972 and 1990, 159 pediatric patients were admitted to the Barrow Neurological Institute with acute traumatic spinal cord or vertebral column injuries. Of these, 26 children (16%) sustained SCIWORA. The mechanism of injury, its severity, and the prognosis for recovery were related to the patient's age. In young children, SCIWORA accounted for 32% of all spinal injuries and tended to be severe; 70% were complete injuries. In older children, SCIWORA accounted for only 12% of the spinal injuries, was rarely associated with a complete injury, and had an excellent prognosis for complete recovery of neurologic function. As with other types of spinal cord injuries, the severity of neurological injury was the most important predictor of outcome. Patients with complete neurological deficits from SCIWORA had a poor prognosis for recovery of neurological function.

Adolescent↗
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↗
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↗
PubMed1990

Effect of intra-arterial tissue plasminogen activator and urokinase on autologous arterial emboli in the cerebral circulation of rabbits [corrected].

We conducted a randomized, blinded controlled trial to test the efficacy of fibrinolytic therapy with tissue plasminogen activator and urokinase in the treatment of acute embolic stroke. Embolic stroke was simulated in rabbits by injecting three 0.5 x 0.5 mm fragments of autologous arterial thrombus harvested from a traumatized auricular artery. Thirty minutes after embolization the rabbits were blindly treated with tissue plasminogen activator (n = 21), urokinase (n = 20), or 0.9% saline (n = 20). At 6 hours the rabbits were sacrificed, and the cerebral vasculature was inspected for the location and number of emboli. The brain was then cut into 0.5-cm-thick coronal sections and stained with triphenyltetrazolium chloride to define areas of infarction. Treatment with either tissue plasminogen activator or urokinase significantly reduced the number of emboli present in the cerebral circulation (p less than 0.05). The area of ischemic injury was also significantly reduced (p less than 0.05) by acute fibrinolytic therapy with either tissue plasminogen activator or urokinase. However, only treatment with tissue plasminogen activator significantly reduced (p less than 0.05) the incidence of infarction. There was no evidence of intracerebral hemorrhage in any rabbit. Early fibrinolytic therapy improved outcome in this model of acute embolic stroke.

Animals↗
PubMed1990

Petrous carotid-to-intradural carotid saphenous vein graft for intracavernous giant aneurysm, tumor, and occlusive cerebrovascular disease.

In the management of cavernous sinus aneurysms, cavernous sinus tumor, and cavernous internal carotid artery (ICA) stenosis, a direct arterial bypass around the pathology may be required. A series of 18 patients is presented in whom a petrous ICA to subarachnoid ICA saphenous vein bypass procedure was performed. The advantages of a short large-caliber venous graft entirely within the skull account for the high patency rate (17 of 18 patients) in this series. This vascular bypass can be recommended in the management of patients whose intracavernous ICA must be sacrificed.

Adult↗
PubMed1990

Grading and staged resection of cerebral arteriovenous malformations.

The decision to recommend operative excision of an AVM should be based on an objective assessment of the long-term prognosis of the untreated lesion and the risks of surgery. We have developed a relatively uncomplicated, preoperative grading system for AVMs. This grading system will allow the surgeon to estimate the risk of completely excising a particular AVM. In our series, staged management was used to reduce the risk of excising large AVMs. These lesions were managed by preoperative transfemoral embolization, intraoperative selective embolization combined with feeding artery ligation and, finally, surgical excision. The stepwise throttling of large AVMs appears to minimize the risks of NPPB. The extensive AVM embolization and feeding vessel ligation integral to this staged approach serve another, equally important purpose--the control of intraoperative bleeding--a factor that previously limited the surgical excision of many large AVMs. Using this management strategy, we have successfully excised 25 exceptionally large AVMs with no mortality and only one seriously disabling, surgically related deficit.

Adult↗
PubMed1989

The efficacy of intravenous nimodipine in the treatment of focal cerebral ischemia in a primate model.

The clinical and pathological effects of nimodipine on cerebral infarction were investigated in 12 male baboons. In randomized/blind trials, six animals given intravenous nimodipine (2 micrograms/kg/min load, 1 microgram/kg/min maintenance) for 96 hours starting 50 minutes before 6-hour double-clip occlusion of the middle cerebral artery were compared to 6 control animals. Standardized neurological examinations were performed by examiners blinded to the animals' therapy on Day 7 and Day 14 after stroke. On Day 14 the animals were killed. The brains were studied pathologically, and the relative areas of infarction were quantified. Intracranial pressure was lower in nimodipine-treated animals; however, the range of intracranial pressure values in each group was broad. Two control animals with high intracranial pressure died. There were no deaths among the nimodipine-treated animals. The neurological scores on Days 7 (P less than or equal to 0.01) and 14 (P less than or equal to 0.05) were significantly different between the two groups. The nimodipine-treated animals had less clinical evidence of infarction compared to controls. Nimodipine-treated animals tended to have smaller areas of infarction; however, the difference between the two groups was not statistically significant. The infusion of nimodipine in the treatment of focal cerebral ischemia is safe and does not appear to aggravate the extent of infarction or to exacerbate intracranial hypertension. The clinical neurological evaluations indicate that nimodipine may improve or preserve neurological outcome after stroke.

Animals↗
PubMed1989

Management of juvenile spinal AVM's by embolization and operative excision. Case report.

A small group of spinal arteriovenous malformations (AVM's) most commonly present in children or young adults, are characterized by a large size, high flow, the presence of multiple feeders, and frequent extension to paraspinous structures. Cardiac output requirements may be significantly increased by these so-called "juvenile" malformations, and a bruit is commonly noted. This report describes the obliteration of a juvenile spinal AVM. Staging of embolization and operative procedures was used to obliterate the AVM successfully without morbidity.

Adult↗
PubMed1988

Surgical management of large AVMs.

The surgical management of large AVMs (those greater than 6 cm in maximal diameter) should be based on a thorough understanding of the chronic hemodynamic changes produced by lesions and the acute stress placed on the cerebral vasculature by their removal. In addition to haemorrhage, seizure, and headache, these larger lesions often present with symptoms of cerebral vascular insufficiency. Angiography frequently demonstrates a high-flow arteriovenous shunt with evidence of vascular steal from the surrounding brain. In many cases there is a virtual absence of normal hemispheric filling. When the steal is sufficient to produce an area of chronic ischaemia in the brain surrounding the AVM, there is an increased risk of swelling and haemorrhage associated with complete excision. We have developed a strategy for the surgical management of these large lesions that involves a stepwise reduction of flow through the AVM using pre- and intraoperative embolization, followed by complete excision. The details of this management strategy are described, and results in 24 patients with exceptionally large AVMs are presented.

Adult↗
PubMed1988

Pediatric spinal trauma. Review of 122 cases of spinal cord and vertebral column injuries.

A review of 122 pediatric cases of vertebral column and spinal cord injuries is presented. These relatively uncommon injuries can be characterized by four distinct injury patterns: fracture only, fracture with subluxation, subluxation only, and spinal cord injury without radiographic abnormality. The immature pediatric spine has several anatomical and biomechanical features that distinguish it from the mature adolescent spine and, accordingly, the frequency of the injury type, the level of spine injury, and the incidence of neurological compromise were found to vary with the age of the patient. Follow-up data were obtained in 93% of the cases (median duration 44 months). No patient was made worse by treatment, 89% of the patients with incomplete myelopathy on admission were improved on their last examination, and 20% of the patients with a complete myelopathy had evidence of significant recovery of function. The authors conclude that the outcome after pediatric spinal trauma is good.

Adolescent↗
PubMed1988

Myelopathy due to epidural varicose veins of the cervicothoracic junction. Case report.

A 30-year-old man presented with a subacute course of myelopathic signs and symptoms. Magnetic resonance imaging demonstrated an epidural mass lesion of the spinal canal at the cervicothoracic junction causing compression of the spinal cord. Laminectomy with resection of this lesion revealed a large varix with acute and chronic thrombus. Postoperatively, an improvement in neurological function occurred. Spinal epidural varicosities have been reported as an etiological factor in lumbar and sacral radiculopathies. This is the first reported case of spinal cord compression in association with spinal epidural varices. The diagnosis, pathophysiology, and management of this disorder are presented.

Adult↗
PubMed1986

Chronic cerebral vasospasm: effect of volume and timing of hemorrhage in a canine model.

The effect of altering the volume and timing of hemorrhage on the severity of spasm was studied in a canine model. All animals received three cisterna magna injections of fresh unheparinized autologous arterial blood. Selective left vertebral arteriograms were obtained during the week before and exactly 7 days after the initial subarachnoid injection. Increasing volumes of hemorrhage (from 9 to 15 ml of blood) delivered over 24 hours produced increasingly more severe arterial spasm, with reductions in basilar artery diameter of 37% +/- 14 (SD) and 58% +/- 15, respectively. Delay of the final injection of blood to 96 hours in the 15-ml hemorrhage group resulted in even more intense spasm, with an average 71% +/- 12 reduction in basilar artery diameter. Serial angiographic evaluation demonstrated the resolution of spasm in this group over approximately 3 weeks. Finally, small, late rebleeding episodes resulted in the rapid onset of intense spasm. Our results support the clinical impression of previous studies that the severity of spasm is related to the volume of hemorrhage and, in addition, suggest that the time course of hemorrhage may play a significant role in determining the overall severity of chronic cerebral vasospasm.

Animals↗