Biomedical subjects

P D Le Roux

Publications and source records attributed to P D Le Roux.

At least 19 recordsLinked to original sources

PubMed2001

Robot-assisted microsurgery: a feasibility study in the rat.

OBJECTIVE: Telerobotic surgery is a novel technology that can improve a surgeon's manual dexterity as well as the results achieved with microsurgical procedures. METHODS: A prototype Robot-Assisted MicroSurgery (RAMS) microdexterity enhancement system developed by the Jet Propulsion Laboratory and MicroDexterity Systems, Inc., was tested in 10 rats. Carotid arteriotomies were created and closed using either the RAMS system or conventional microsurgical techniques. The time required, the technical quality (vessel patency and suture line integrity), the error rate, and subjective difficulty were compared. RESULTS: All procedures were successfully completed using the RAMS system to manipulate the vessel but not to hold the needle or place the sutures. The precision, technical quality, and error rate of telerobotic surgery were similar to those of conventional techniques. However, the use of the RAMS system was associated with a twofold increase in the length of the procedure. CONCLUSION: Surgery using a microdexterity enhancement system, or RAMS prototype, is feasible. With further development, such as a stereotelevisualization and haptic feedback system, this system could be used for telerobotic surgery in neurosurgical practice.

Animals↗

PubMed2001

Blood transfusion during aneurysm surgery.

INTRODUCTION: Increasing costs and concerns about blood supply safety have led to a reevaluation of blood transfusion practices. This study was undertaken to examine blood use during aneurysm surgery. METHODS: We performed a retrospective analysis of hospital records including operative, anesthetic, and nursing notes, computed tomographic scans, and four-vessel angiographic films of 547 patients undergoing surgery for ruptured and unruptured cerebral aneurysms at Harborview Medical Center in Seattle. During the review period, the transfusion threshold was not altered. RESULTS: A total of 134 patients (24.5%) received an intraoperative blood transfusion (median number of units, 2; range, 1-17). Preoperative factors associated with intraoperative blood use included older patient age (P < 0.001), lower hematocrit level on admission (P = 0.007), ruptured rather than unruptured aneurysm (P = 0.004), severe intraventricular hemorrhage (P = 0.03), and larger aneurysm size (P = 0.004). Factors not associated with intraoperative blood transfusion included past medical history (including cardiac or pulmonary disease), admission clinical grade after aneurysm rupture, findings such as hydrocephalus on computed tomographic scanning, and aneurysm location and aneurysm neck-to-fundus ratio. Also associated with blood transfusion during surgery were intraoperative aneurysm rupture (P < 0.0001), intracerebral hematoma evacuation (P = 0.02), and obliteration of multiple aneurysms (P = 0.002). Among patients who received an intraoperative transfusion, those who experienced an aneurysm rupture required an average of 3.6 +/- 0.35 units, whereas patients who did not have a rupture required 1.9 +/- 0.12 units (P = 0.001). Postoperatively, a total of 244 patients (44.6%), including 77 who received blood intraoperatively, required a blood transfusion (median number of units, 2; range, 1-31). Postoperative blood transfusion was associated with the treatment of patients with subarachnoid hemorrhage (P < 0.0001), particularly among poor-grade patients who developed medical complications. CONCLUSION: Blood transfusion can be expected in one in five patients undergoing aneurysm surgery. Reducing intraoperative rupture may reduce the need for blood products.

Adolescent↗

PubMed1999

Intracranial aneurysms and subarachnoid hemorrhage management of the poor grade patient.

Between 20 and 30% of patients who suffer cerebral aneurysm rupture are in poor clinical grade when first evaluated. Management of these patients is controversial and challenging but can be successful with an aggressive proactive approach that begins with in the field resuscitation and continues through rehabilitation. In this article we review the epidemiology, pathology and pathophysiology, clinical features, evaluation, surgical and endovascular management, critical care, cost, and outcome prediction of patients in poor clinical grade after subarachnoid hemorrhage.

Adult↗

PubMed1999

Postoperative pain after lumbar disc surgery: a comparison between parenteral ketorolac and narcotics.

OBJECTIVE: Lumbar discectomy is a common elective surgical procedure but many patients still experience postoperative back pain which may delay hospital discharge. We therefore evaluated the efficacy of a parenteral non-steroidal antiinflammatory agent, ketorolac, for the management of post-surgical pain. METHODS: Fifty three patients undergoing lumbar discectomy at a Medical School affiliated Veterans Administration hospital were randomly assigned to receive either: 1) 30 mg intramuscular ketorolac upon surgical closure and every 6 hours for 36 hours and narcotic analgesics as needed (PRN); or 2) only narcotic analgesics as needed. A blinded observer recorded the average, minimum and maximum postoperative pain intensity using a Numeric Pain Intensity Scale; total postoperative narcotic consumption, complications, length of hospitalization (from surgery to discharge) and outcome at 6 weeks. RESULTS: The patients who received ketorolac reported significantly lower average (p < 0.001), minimum (p < 0.001), and maximum (p < 0.001) pain scores than patients receiving only narcotic analgesics. Cumulative narcotic doses (standardized to parenteral morphine) were significantly lower in the ketorolac group (p < 0.001). There was no significant difference between groups in the frequency of side effects, and no complication specifically associated with ketorolac use was observed. Mean length of hospitalization was significantly shorter (p = 0.05) in patients receiving ketorolac than in patients receiving only narcotics. Six weeks after surgery 5 (19.2%) patients who received only narcotics were troubled by persistent back pain. By contrast, all patients who received ketorolac were free of back pain at follow-up (p = 0.03). CONCLUSIONS: These results suggest that ketorolac, when used with PRN narcotics, is more effective than PRN narcotics alone for postoperative pain following lumbar disc surgery. In addition, this strategy also may contribute to early discharge from hospital after lumbar disc surgery.

Adult↗

PubMed1999

Cerebral cortical neuron apoptosis after mild excitotoxic injury in vitro: different roles of mesencephalic and cortical astrocytes.

OBJECTIVE: Increasing evidence supports the presence of neuronal apoptosis after ischemic or excitotoxic brain injury. Astrocytes, which exhibit significant regional differences in function, may exert a protective effect on neurons exposed to ischemic injury. We examined the effects of astrocytes derived from different regions of the central nervous system on neuronal apoptosis after mild excitotoxic injury in tissue culture. METHODS: Purified astrocyte cultures derived from P4 rat cerebral cortex or mesencephalon showed transient cell swelling but no cell death when exposed to 50 micromol/L glutamate for 5 minutes. When mixed neuronal/glial cocultures were exposed to the same glutamate dose, neuron death was observed. Necrotic and apoptotic cell death during 24 hours was examined using morphological criteria, nuclear staining, triphosphate nick end labeling, and trypan blue exclusion. RESULTS: We found that cortical neurons that elaborate a more extensive dendritic arbor when grown on homotypic astrocytes are more likely to undergo apoptosis than neurons with a limited dendritic arbor grown on heterotypic astrocytes. By contrast, a similar number of neurons undergo necrotic cell death. CONCLUSION: This finding may be associated with 1) increased vulnerability of neurons with a more elaborate dendrite structure to mild excitotoxic injury, or 2) regional differences in the ability of astrocytes to attenuate apoptosis.

Animals↗

PubMed1998

Risks and benefits of diagnostic angiography after aneurysm surgery: a retrospective analysis of 597 studies.

INTRODUCTION: Cerebral angiography performed after aneurysm surgery can identify causes of morbidity and mortality that may be corrected. The risks and benefits of angiography that is performed after aneurysm surgery, however, have not been clearly defined. We therefore reviewed our experience with postoperative angiography to determine its dangers and benefits. METHODS: During 10 years, 543 consecutive patients received treatment for cerebral aneurysms. A retrospective analysis of 597 diagnostic angiograms obtained after aneurysm surgery for 494 of these patients was performed. RESULTS: Catheter-induced vessel spasm and dissection, occurring most frequently in the internal carotid artery, were observed in seven (1.2%) and six (1%) studies, respectively. No angiography-associated strokes were identified. No association between age, smoking, hypertension, blood pressure, atherosclerosis, or severe vasospasm and angiographic complications was observed. Aneurysm remnants were identified in 36 (5.7%) of the 637 aneurysms that were surgically treated. Atherosclerosis (P < 0.01) or multiple clip applications (P < 0.01) were significantly associated with aneurysm remnants. Angiographic vessel occlusion was observed in 28 (5.7%) patients and resulted in stroke in 14 of these patients. Vessel occlusion was significantly associated with increasing aneurysm size (P < 0.001), atherosclerosis (P < 0.001), temporary clips (P < 0.001), multiple clips (P=0.03), multiple clip applications (P=0.001), and a new postoperative neurological deficit (P=0.002). Severe vasospasm and newly identified aneurysms were observed in 51 and 16 patients, respectively. CONCLUSION: Angiography after aneurysm surgery is safe and can be routinely performed. Angiography after aneurysm surgery should be particularly considered for patients with large aneurysms or cerebrovascular atherosclerosis and for those who develop new postoperative neurological deficits.

Adolescent↗

PubMed1998

Comparison of balloon angioplasty and papaverine infusion for the treatment of vasospasm following aneurysmal subarachnoid hemorrhage.

OBJECT: The purpose of this study was to test the hypothesis that balloon angioplasty is superior to papaverine infusion for the treatment of proximal anterior circulation arterial vasospasm following subarachnoid hemorrhage (SAH). Between 1989 and 1995, 125 vasospastic distal internal carotid artery or proximal middle cerebral artery vessel segments were treated in 52 patients. METHODS: Blood flow velocities of the involved vessels were assessed by using transcranial Doppler (TCD) monitoring in relation to the day of treatment with balloon angioplasty or papaverine infusion. Balloon angioplasty and papaverine infusion cohorts were compared based on mean pre- and posttreatment velocity at 24 and 48 hours using the one-tailed, paired-samples t-test. Balloon angioplasty alone was performed in 101 vessel segments (81%) in 39 patients (75%), whereas papaverine infusion alone was used in 24 vessel segments (19%) in 13 patients (25%). Although repeated treatment after balloon angioplasty was needed in only one vessel segment, repeated treatment following papaverine infusion was required in 10 vessel segments (42%) in six patients because of recurrent vasospasm (p < 0.001). Seven vessel segments (29%) with recurrent spasm following papaverine infusion were treated with balloon angioplasty. Although vessel segments treated with papaverine demonstrated a 20% mean decrease in blood flow velocity (p < 0.009) on posttreatment Day 1, velocities were not significantly lower than pretreatment levels by posttreatment Day 2 (p = 0.133). Balloon angioplasty resulted in a 45% mean decrease in velocity to a normal level following treatment (p < 0.001), a decrease that was sustained. CONCLUSIONS: Balloon angioplasty is superior to papaverine infusion for the permanent treatment of proximal anterior circulation vasospasm following aneurysmal SAH.

Adult↗

PubMed1998

Management of cerebral aneurysms. How can current management be improved?

In the present article, we have reviewed potential avenues for improvement in the care of and present management of patients with cerebral aneurysms. Opportunities exist in areas of prevention, systems approach and organization of centers, physician and patient education, screening, and advances in surgical and endovascular therapy. All such advances, however, depend on rigorous academic evaluation. This issue represents a review of the current management of cerebral aneurysms, hopefully providing a basis for future improvements in the treatment of these lesions.

Case Management↗

PubMed1998

Management of the ruptured aneurysm.

Rupture of cerebral aneurysms is a complex and devastating pathophysiologic event. The successful management of aneurysm rupture requires a dedicated multidisciplinary team. This article reviews pathophysiology; clinical grading that can be used to predict outcome and guide therapy; factors that may affect outcome such as rebleeding, poor clinical grade, intracerebral hemorrhage, intraventricular hemorrhage, and acute hydrocephalus; preoperative care and assessment; pharmacological therapy; anesthetic, surgical, and endovascular considerations; and postoperative care following aneurysm rupture.

Aneurysm, Ruptured↗

PubMed1998

Subarachnoid hemorrhage and cerebral aneurysms in the elderly.

Advanced age is associated with a less favorable outcome following aneurysmal SAH, in large part, because of associated medical conditions. Nevertheless, available data suggest that elderly patients often benefit from aggressive treatment and that a reasonable outcome at a reasonable cost can be expected in selected patients. Emerging technologies such as endovascular treatment of ruptured and unruptured aneurysms continue to improve treatment options in the elderly population. Physiologic rather than chronologic age together with the patient's clinical condition and personal and family considerations should form the basis of any recommended treatment approach in the elderly patient with a cerebral aneurysm.

Age Factors↗

PubMed1998

Perioperative and intensive care unit care of patients with aneurysmal subarachnoid hemorrhage.

Subarachnoid hemorrhage (SAH) is a complex pathophysiological event that results in a number of intracranial and systemic alterations. The effective management of SAH has its foundation in the prevention, early diagnosis, and correction of complications. Successful outcome in these compromised patients requires close monitoring and intensive care. This article will review the pathophysiology of SAH, identify the most common medical and neurological events that complicate SAH, examine the impact of secondary cerebral insults after aneurysm rupture, and outline current ICU care for SAH.

Cerebrovascular Circulation↗

PubMed1998

Surgical approaches to basilar bifurcation aneurysms.

Basilar bifurcation aneurysms are technically challenging and their treatment is often associated with greater morbidity than aneurysms located in the anterior circulation. These lesions can be treated using surgical, endovascular, or a combination of techniques. Several surgical approaches have evolved to treat basilar bifurcation aneurysms; none, however, is suitable for all aneurysms in this location. This article reviews the natural history, clinical presentation, evaluation, and selection of treatment approach and details various surgical techniques. The use of endovascular techniques is reviewed briefly.

Basilar Artery↗

PubMed1997

Cerebral arteriovenous oxygen difference: a predictor of cerebral infarction and outcome in patients with severe head injury.

Jugular bulb oxygen monitoring can be used to estimate the adequacy of cerebral blood flow to support cerebral metabolism after severe head injury. In the present study, the authors studied the cerebral arteriovenous oxygen difference (AVDO[2]) before and after treatment in 32 head-injured patients (Glasgow Coma Scale scores < or = 8) to examine the relationships among AVDO and cerebral perfusion pressure (CPP), delayed cerebral infarction, and outcome. Fifteen patients (Group A) underwent craniotomy for hematoma evacuation and 17 (Group B) received mannitol for sustained intracranial hypertension (intracranial pressure > 20 mm Hg, > 10 minutes). Radiographic evidence of delayed cerebral infarction was observed in 14 patients. Overall, 17 patients died or were severely disabled. Cerebral AVDO(2) was elevated before craniotomy or mannitol administration; the mean AVDO(2) for all patients before treatment was 8.6 +/- 1.8 vol%. Following craniotomy or mannitol administration, the AVDO(2) decreased in 27 patients and increased in five patients (mean AVDO(2) 6.2 +/- 2.1 vol% in all patients; 6 +/- 1.9 vol% in Group A; and 6.4 +/- 2.4 vol% in Group B). The mean CPP was 75 +/- 9.8 mm Hg and no relationship with AVDO(2) was demonstrated. Before treatment, the AVDO(2) was not associated with delayed cerebral infarction or outcome. By contrast, a limited improvement in elevated AVDO(2) after craniotomy or mannitol administration was significantly associated with delayed cerebral infarction (Group A: p < 0.001; Group B: p < 0.01). Similarly, a limited improvement in elevated AVDO(2) after treatment was significantly associated with an unfavorable outcome (Group A: p < 0.01; Group B: p < 0.001). In conclusion, these findings strongly indicate that, despite adequate cerebral perfusion, limited improvement in elevated cerebral AVDO(2) after treatment consisting of either craniotomy or mannitol administration may be used to help predict delayed cerebral infarction and poor outcome after traumatic brain injury.

Adult↗

PubMed1996

Reactive astroglia support primary dendritic but not axonal outgrowth from mouse cortical neurons in vitro.

Reactive astrocytes are thought to be impediments to axon regrowth following injury to the mammalian central nervous system. Axon and dendrite growth, however, appear to be differently controlled by normal astrocytes in vitro. To determine whether reactive astrocytes differ in their ability to support axons or dendrites, embryonic (E18) mouse cortical neurons were cocultured with P4 and P12 rat astroglial cells derived from normal or lesioned cortex. After 5 days in vitro, axon and dendrite outgrowth from isolated neurons was quantified with double-labeling immunohistochemical techniques. Reactive astrocytes were able to maintain primary dendrite growth, principally primary dendrite number. Axon elongation, however, was significantly reduced on both neonatal and more mature reactive astrocytes. These results indicate that reactive astrocytes may exhibit separate mechanisms to control dendrite and axon growth.

Animals↗

PubMed1996

The incidence of surgical complications is similar in good and poor grade patients undergoing repair of ruptured anterior circulation aneurysms: a retrospective review of 355 patients.

To determine how clinical grade after subarachnoid hemorrhage impacts operative characteristics and the incidence of intra- and postoperative surgical complications, we retrospectively compared the surgical management of all good grade (n = 224) and poor grade (n = 131) patients who suffered ruptured anterior circulation aneurysms between 1983 and 1993. The majority of good grade (74.2%) and poor grade (89.8%) patients underwent surgery < 3 days after subarachnoid hemorrhage. The results in this series demonstrate that severe cerebral swelling, often secondary to intracerebral hemorrhage, was significantly more frequent in poor grade patients. The incidence of complications, such as failure to occlude the aneurysm, major vessel occlusion, intraoperative aneurysm rupture, or surgical contusion, however, was similar in poor grade and good grade patients. We conclude, therefore, that except for severe cerebral swelling associated with intracerebral hemorrhage, the risk of surgical complications is similar in good and poor grade patients undergoing surgical repair of ruptured anterior circulation aneurysms.

Aneurysm, Ruptured↗

PubMed1996

Predicting outcome in poor-grade patients with subarachnoid hemorrhage: a retrospective review of 159 aggressively managed cases.

To determine what factors predict outcome, the authors retrospectively reviewed the management of all 159 poor-grade patients admitted to Harborview Medical Center at the University of Washington who suffered aneurysmal subarachnoid hemorrhage between 1983 and 1993. Favorable outcome (assessed by the Glasgow Outcome Scale) occurred in 53.9% of Hunt and Hess Grade IV, and 24.1% of Grade V patients. Outcome was largely determined by the initial hemorrhage and subsequent development of intractable intracranial hypertension or cerebral infraction. Using multivariate analysis, the authors developed three models to predict outcome. It was found that predicting outcome based only on clinical and diagnostic criteria present at admission may have resulted in withholding treatment from 30% of the patients who subsequently experienced favorable outcomes. It is concluded that aggressive management including surgical aneurysm obliteration can benefit patients with poor neurological grades and should not be denied solely on the basis of the neurological condition on admission.

Adolescent↗

PubMed1996

Predicting length of hospital stay and cost by aneurysm grade on admission.

To determine the relationship between clinical grade on admission and treatment cost after aneurysm rupture, the authors retrospectively examined the length of hospital stay (LOS) and total hospitalization costs (excluding professional fees) for 543 patients admitted for aneurysm surgery between 1983 and 1993. The overall median LOS was 18 days, with a range of 1 to 165 days. Increased median LOS correlated with Hunt and Hess Grades 0 to IV on admission (p < 0.001). Median LOS for Grade V patients was reduced, in part, because of early mortality. Increased treatment cost also correlated with worse admission clinical grade (p < 0.001). A significant proportion of total expenditures occurred early in the hospitalization for patients in all clinical grades. Identification of additional factors affecting the cost of aneurysm treatment is indicated to complement treatment outcome studies.

Adolescent↗

PubMed1995

Independent regulation of primary dendritic and axonal growth by maturing astrocytes in vitro.

Whereas axon growth is limited in the mature mammalian central nervous system (CNS), dendritic remodeling occurs throughout life. Since glia can regulate neurite growth during development, we tested whether glia from the mature CNS differ in their ability to support axon and dendrite growth. Cortical neurons were co-cultured with neonatal or mature astroglial, and dendrite and axon outgrowth quantified after 5DIV using immunohistochemical techniques. Primary dendritic growth was supported equally well by mature and immature astrocytes. By contrast, mature astrocytes demonstrated a reduced ability to support axon growth. We propose that the independent regulation of axon and dendrite growth by astrocytes provides a means by which the mature nervous system may adjust its function to activity and the environment.

Animals↗