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Biomedical subjects

K A Greene

Publications and source records attributed to K A Greene.

At least 19 recordsLinked to original sources

Continuous hemodialysis for the management of acute renal failure in the presence of cerebellar hemorrhage. Case report.

In this report the authors describe the use of continuous venovenous hemodialysis (CVVHD) in a medically unstable patient who suffered from a spontaneous cerebellar hemorrhage. Conventional dialysis techniques carry the risk of developing the dialysis disequilibrium syndrome (DDS) when performed in the presence of a variety of intracranial diseases. The CVVHD technique was used successfully in a morbidly obese, short-statured woman with a spontaneous hypertensive intraparenchymal cerebellar hemorrhage. The woman experienced acute renal failure several days after her hemorrhage and her general medical condition prevented her from undergoing surgical evacuation. The CVVHD did not result in elevations in intracranial pressure (ICP) and the patient made a full recovery from both acute renal failure and life-threatening posterior fossa hemorrhage. This case is noteworthy because of the absence of abnormally high ICP elevations or development of DDS in a patient with a large acute posterior fossa intraparenchymal brain hemorrhage and acute renal failure whose case was managed with CVVHD in the acute period.

Acute Kidney Injury

Acute axis fractures. Analysis of management and outcome in 340 consecutive cases.

STUDY DESIGN: Retrospective review of acute axis fractures treated at a tertiary referral center. OBJECTIVE: To determine the optimal treatment of axis fractures based on 340 cases from a single institution. SUMMARY OF BACKGROUND DATA: Axis fractures account for almost 20% of acute cervical spine fractures. However, their management and the clinical criteria predictive of nonoperative failure remain unclear. METHODS: Admission imaging studies and clinical variables were obtained for 340 consecutive axis fracture patients. Fractures were classified as as odontoid Type I, II, or III with dena displacement on admission roentgenograms; hangman's fractures of Francis grade and Effendi type; and miscellaneous fractures. Treatment methods were documented, and outcomes were based on dynamic lateral roentgenograms, clinical examination, or telephone interviews at last follow-up. RESULTS: Follow-up data were available in 92% of cases. Type II odontoid fractures comprised 35% of all axis fractures, were the most difficult to treat, and had the highest nonunion rate (28.4%). Odontoid displacement of 6 mm or more was associated with Type II nonunion (chi-square = 33.74, P < 0.0001). Patients underwent surgical fusion if fracture alignment could not be maintained by an external orthosis, or if they had odontoid fractures with transverse ligament disruption, Type II odontoid fractures with dens displacement of at least 6 mm, or hangman's fractures of severe Francis grade or Effendi type. CONCLUSIONS: Type II odontoid fractures have the highest nonunion rate and were associated with dens displacement of 6 mm or greater. Early surgical fusion is recommended for acute fracture instability despite external immobilization, transverse ligament disruption, Type II odontoid fractures with dens displacement of at least 6 mm on admission, or severe Francis grade or Effendi-type hangman's fractures. Otherwise, nonoperative management is sufficient.

Adolescent

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part II: Relationship to clinical course and outcome variables during acute hospitalization.

Patients with a nonpenetrating head injury and traumatic subarachnoid hemorrhage (tSAH) on admission head computed tomography scan (n = 240) were compared with patients without tSAH matched in terms of admission postresuscitation Glasgow Coma Scale (GCS) values, age, sex, and the presence of one or more types of intracranial mass lesions. Admission Injury Severity Score was higher only in tSAH patients with admission GCS scores between 13 and 15; GCS values at 6, 24, and 48 hours were lower for tSAH patients. Patients with tSAH underwent fewer craniotomies, but more than twice as many tSAH patients had high intracranial pressure at the time of ventriculostomy placement and 6 hours after admission. tSAH patients underwent more chest procedures and their incidence of hypoxia and hypotension was greater. tSAH patients spent more days in intensive care unit, more total days hospitalized, and had worse Glasgow Outcome Scale scores at acute hospital discharge. Fewer tSAH patients were discharged home, and almost 1.5 times as many tSAH patients died during hospitalization. Given a similar overall degree of injury at admission, patients with tSAH associated with a nonpenetrating head injury had a worse outcome than similar patients without tSAH.

Accidents, Traffic

Injuries involving the transverse atlantal ligament: classification and treatment guidelines based upon experience with 39 injuries.

Comprehensive anatomic and clinical analyses of 39 patients with injuries involving the transverse atlantal ligament or its osseous insertions were performed to assess the morphology of the injured ligaments and the patients' capacity to heal. Injuries of the upper cervical spine were screened with plain radiographs, thin-section computed tomography, and magnetic resonance imaging studies. The injuries were classified as disruptions of the substance of the ligament (Type I injuries, n = 16) or as fractures and avulsions involving the tubercle for insertion of the transverse ligament on the C1 lateral mass (Type II injuries, n = 23). These two types of injuries had distinctly different clinical characteristics that were useful for determining treatment. Type I injuries were incapable of healing satisfactorily without internal fixation; they should be treated with early surgery. Type II injuries, which rendered the transverse ligament physiologically incompetent even though the ligament substance was not torn, should be treated initially with a rigid cervical orthosis, because they had a 74% success rate nonoperatively. Surgery should be reserved for patients with Type II injuries that have nonunion with persistent instability after 3 to 4 months of immobilization. Type II injuries had a 26% rate of failure of immobilization; therefore, close monitoring is needed to detect patients who will require delayed operative intervention.

Adolescent

Intra-aortic balloon pump counterpulsation in the management of concomitant cerebral vasospasm and cardiac failure after subarachnoid hemorrhage: technical case report.

We report two patients who had symptomatic cerebral vasospasm and cardiac failure after aneurysmal subarachnoid hemorrhage and who were treated successfully with intra-aortic balloon pump counterpulsation therapy. Both patients developed congestive heart failure and pulmonary edema while receiving postoperative hypertensive, hypervolemic, hemodilutional (Triple-H) therapy for symptomatic cerebral vasospasm. Both cases of cardiac failure were refractory to maximum pressor and inotropic infusions. Intra-aortic balloon pump counterpulsation was used to optimize cardiac performance to allow continuation of Triple-H therapy and to maintain adequate cerebral perfusion in an attempt to decrease the risk of cerebral ischemic complications. Both patients have had good long-term outcomes. These two cases illustrate the potential usefulness of the intra-aortic balloon pump as an adjunct to Triple-H therapy in patients with symptomatic cerebral vasospasm and cardiac failure. To our knowledge, this report documents the first clinical application of this adjunctive therapy for vasospasm after aneurysmal subarachnoid hemorrhage.

Aged

Pharmacological management of spinal cord injury: current status of drugs designed to augment functional recovery of the injured human spinal cord.

Spinal cord injury often results in devastating physical, psychological, and economic disabilities. Research efforts are directed toward providing prognostic outcome data and animal models that parallel the human disorder, thereby elucidating the mechanisms responsible for its dismal clinical prognosis. Investigators continue to search for pharmacological agents that halt the cascade of events that lead to loss of function after cord injury. The scientific and federal regulatory processes by which new drugs are discovered and implemented clinically permit clinicians to evaluate the potential benefits of any new agent, and provide an estimate of the duration required for promising new agents to be made clinically available. Understanding these processes makes the task of classifying the availability status of new drugs much simpler, allowing rational dissemination of realistic information to patients and their families frequently made desperate for viable alternatives to the prospect of permanent paralysis. In this review, we describe the scientific and regulatory processes necessary for the clinical introduction of new drugs using spinal cord injury as an example. A classification scheme based on current Food and Drug Administration regulations is presented that provides drug availability status at a glance. It is hoped that such an organizational scheme will be of practical benefit to clinicians involved in the management of spinal cord-injured patients.

Animals

Transient resolution of bilateral tremor after unilateral thalamotomy, associated with focal injury of the corpus callosum: case report.

We present a patient with Parkinson's disease whose bilateral tremor transiently resolved after a unilateral left ventrolateral thalamotomy. The transient resolution of the bilateral tremor was associated with a focal thalamic lesion and a second lesion in the corpus callosum. The mechanism of this phenomenon may be related to temporary disruption of descending bilateral corticostriate projections by the callosal lesion.

Corpus Callosum

Glossopharyngeal neuralgia associated with vascular compression and choroid plexus papilloma.

We report two cases of presumed idiopathic glossopharyngeal neuralgia that were discovered intraoperatively to be associated with compression by choroid plexus papillomas, and by a variable degree of vascular compression at the root entry zones of cranial nerves IX and X. The combination of the two entities in glossopharyngeal neuralgia has not previously been reported.

Adult

Novel heuristics of functional neural networks: implications for future strategies in functional neurosurgery.

A hypothesis is proposed that (a) the skeletomotor basal ganglia-thalamocortical loop functions as a model of the behavior of the body and the environment, and that (b) dopaminergic neurons of the substantia nigra pars compacta comprise the substrates of an error distribution system projecting to the striatum. This error signal initiates the learning process in the basal ganglia - learning starts with increasing intensity of the error signal and is complete when the signal is minimized. Parkinson's disease (PD) may be considered as a disruption of learning processes in the basal ganglia that results from progressive degeneration of the substrate that is the error distribution system for this functional motor loop. Numerous clinical and experimental observations obtained from functional procedures for PD that show identical clinical effects in alleviating parkinsonian symptoms, e.g. thermocoagulative lesions and chronic stimulation, can be explained through the use of this conceptual theory of basal ganglia function. Because any controlling neural network must possess a model of the behavior of its controlled object, the heuristics outlined in this theory are broadly applicable for explaining the function of the nervous system, as well as being useful for planning surgical procedures and future strategies in functional neurosurgery.

Basal Ganglia

Intrathrombus administration of tissue plasminogen activator in acute cerebrovascular occlusion.

Intraarterial thrombolysis for acute cerebrovascular occlusion has achieved recanalization at a 50-90% rate. Clinical outcome has been unpredictable. The authors sought to test the hypothesis that intrathrombus administration of recombinant tissue plasminogen activator (rt-PA) would improve recanalization rate and to assess the possibility that clinical outcome would be predicted by the extent of collateral flow. Seven patients with acute cerebrovascular occlusion (less than six hours in 6, twenty-four hours in 1) were treated with intrathrombus rt-PA at 1 mg/minute. Examinations were scored on a five-point motor scale. Collateral flow was assessed angiographically. Vessels recanalized in 5 patients, 3 of whom had good outcomes. Vessels failed to recanalize in 2 patients, 1 of whom had good outcome. Good collateral flow was evident in all 4 patients with good outcome and in none of those with poor outcome. Intrathrombus administration of rt-PA is technically feasible. Favorable clinical outcome is more likely in the presence of good collateral flow. In the absence of good collateral flow, ultra-early intervention may be necessary.

Acute Disease

Anterior communicating artery aneurysm paraparesis syndrome: clinical manifestations and pathologic correlates.

OBJECTIVE: Clinicopathologic evaluation of patients with lower extremity paraparesis/-plegia following rupture and repair of anterior communicating artery (ACoA) aneurysms. DESIGN: Institution-based retrospective review. SETTING: A tertiary neurologic referral center. PATIENTS, PARTICIPANTS: Seven of 101 patients with subarachnoid hemorrhage from ruptured ACoA aneurysms treated between January 1987 and December 1992. MAIN OUTCOME MEASURES: Neurologic status at latest follow-up examination. RESULTS: All patients presented with severe hemorrhage, poor clinical grade, and intracranial hypertension. Motor deficits developed within 7 days of aneurysm rupture and persisted for a mean duration of 39 days. Angiographic evidence of vasospasm in the anterior cerebral artery (ACA) distribution was documented in all cases, and paraparesis persisted beyond the angiographic resolution of vasospasm. All patients had evidence of frontal lobe dysfunction throughout their postoperative courses, and deep venous thrombosis and pulmonary emboli were common causes of morbidity and mortality. Autopsy data supported regional microvascular ischemia within the ACA distribution as the etiology of these motor deficits. CONCLUSIONS: The combination of vasospasm in the ACA distribution and lower extremity weakness associated with cognitive and affective impairment that resolves with time is common in patients with ACoA aneurysms. We propose that this constellation of clinical, radiographic, and pathologic findings be referred to as the "ACoA aneurysm paraparesis syndrome."

Aged

Impact of traumatic subarachnoid hemorrhage on outcome in nonpenetrating head injury. Part I: A proposed computerized tomography grading scale.

The presence of traumatic subarachnoid hemorrhage (tSAH) on admission computerized tomography (CT) scans obtained from patients suffering from severe, nonpenetrating head injury has been shown to be associated with a worse outcome than the injury alone would warrant. However, no previous study has provided a simple means of relating the amount of tSAH, its location, or other abnormal findings on initial head CT scans to outcome in patients with non-penetrating head injury. In this study, admission head CT scans from 252 patients with tSAH, treated at a single institution, were reviewed to ascertain thickness of the tSAH; its location; evidence of mass lesion(s); shift of midline structures (< or = 5 mm vs. > 5 mm); basal cistern effacement; and cortical sulcal effacement. The CT scans were then organized into Grades 1 to 4 with 1 indicating thin tSAH (< or = 5 mm); 2, thick tSAH (> 5 mm); 3, thin tSAH with mass lesion(s); and 4, thick tSAH with mass lesion(s). A stepwise regression analysis of CT features ranked them in descending order of contribution to Glasgow Outcome Scale (GOS) scores at the time of discharge from acute hospitalization as follows: basal cistern effacement, thickness of tSAH, cortical sulcal effacement, presence of mass lesion(s), and location of tSAH. A shift of midline structures was not found to be a significant variable. Further analysis comparing CT grades and admission postresuscitation Glasgow Coma Scale (GCS) scores was highly significant. Patients with lower CT grades had better admission GCS values and discharge GOS scores than those with higher CT grades. From their experience, the authors conclude that their CT grading scale is simple and reliable and relates significantly to outcome at the time of discharge from acute hospitalization.

Adolescent

Transverse atlantal ligament disruption associated with odontoid fractures.

OBJECTIVES: The authors evaluated transverse atlantal ligament integrity in patients with fractures of the odontoid process of the axis. SUMMARY OF BACKGROUND DATA: Injuries of the transverse atlantal ligament can result in atlantoaxial instability after fractures of the atlas or axis, even if osseous healing occurs. METHODS: The clinical histories and follow-up examinations and radiographic data of 30 patients with odontoid fractures were reviewed, using a combination of magnetic resonance (MR) imaging, thin-cut computed tomography (CT), and plain radiographs to evaluate osseous and ligamentous injuries. RESULTS AND CONCLUSIONS: Osteoperiosteal ligamentous avulsion injuries were identified on MR imaging in three patients and were associated with acute and delayed instability and nonunion. The combination of MR imaging, CT, and plain radiographs is useful in evaluating unstable odontoid fractures to facilitate rational treatment planning. Odontoid fractures with transverse ligament injuries should be considered for early surgical stabilization because this combination of injuries is unlikely to heal nonoperatively. Anterior odontoid screw fixation should be avoided when the ligament is injured.

Adolescent

Cardiopulmonary bypass, hypothermic circulatory arrest and barbiturate cerebral protection for the treatment of giant vertebrobasilar aneurysms in children.

Intracranial aneurysms in the pediatric population are rare lesions with a significant proportion occurring as giant aneurysms involving the vertebrobasilar system. The complex anatomy of these lesions frequently creates an extremely difficult management dilemma. We present two patients, a 9-year-old and a 13-year-old, with giant fusiform vertebrobasilar aneurysms, to illustrate the utility of cardiopulmonary bypass, hypothermic circulatory arrest and barbiturate cerebral protection for successful surgical treatment of these complex intracranial vascular lesions in children.

Adolescent