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L N Hopkins

Publications and source records attributed to L N Hopkins.

At least 91 records · Page 5Linked to original sources
PubMed1996

Misdiagnosis of symptomatic cerebral aneurysm. Prevalence and correlation with outcome at four institutions.

BACKGROUND AND PURPOSE: It is not known what fraction of patients with symptomatic cerebral aneurysms are misdiagnosed at initial medical presentation. It is also not clear whether misdiagnosed patients more frequently deteriorate before definitive aneurysm diagnosis and therapy or achieve a poorer outcome than correctly diagnosed patients. METHODS: We reviewed records of consecutive patients with symptomatic cerebral aneurysms managed by four tertiary-care neurosurgical services during a recent 19-month period. Clinical course and outcome were analyzed according to misdiagnosis or correct diagnosis at initial medical evaluation. RESULTS: Fifty-four of 217 patients (25%) were misdiagnosed at initial medical evaluation, including 46 of 121 patients (38%) initially in good clinical condition (clinical grade 1 or 2). Forty-six of 54 patients (85%) in the misdiagnosis group were initially grade 1 or 2 compared with 75 of 163 patients (46%) with correct initial diagnosis (P < .01). Twenty-six of 54 misdiagnosed patients (48%) deteriorated or rebled before definitive aneurysm treatment compared with 4 of 165 correctly diagnosed patients (2%) (P < .001). Among patients initially presenting as clinical grade 1 or 2, overall good or excellent outcome was achieved in 91% of those with correct initial diagnosis and 53% of patients with initial misdiagnosis (P < .001). Deterioration before correct diagnosis accounted for 16 of 67 patients (24%) with poor or worse final outcome in this series. CONCLUSIONS: Patients in good clinical condition with symptomatic cerebral aneurysms were commonly misdiagnosed. Misdiagnosed patients were more likely than correctly diagnosed patients to deteriorate clinically and had a worse overall outcome. Misdiagnosed cases accounted for a significant fraction of overall poor outcomes among consecutive cases of symptomatic aneurysms.

Adult↗
PubMed1996

Vascular neurosurgery: aneurysms, arteriovenous malformations, subarachnoid hemorrhage, and intracranial hemorrhage.

Cerebrovascular disease continues to be a major source of morbidity and mortality in our aging population. Endovascular therapy for the treatment of cerebral aneurysms and associated vasospasm is gaining credibility. Some arteriovenous malformations considered inoperable in the past can now be successfully treated using multimodality therapy. Quantitative measurement of cerebral blood flow is helping to identify patients at risk of ischemic events and defining new guidelines for intervention. New noninvasive imaging modalities may replace conventional angiography for surgical disease. Advances in technology continue to improve our ability to treat cerebrovascular disease prior to irreversible ischemic events.

Cerebral Hemorrhage↗
PubMed1996

FasTRACKER-18.

Explore the source record for details and available documents.

Catheterization, Peripheral↗
PubMed1996

Thrombolysis of the cervical internal carotid artery before balloon angioplasty and stent placement: report of two cases.

The application of endovascular techniques to the treatment of cervical carotid artery bifurcation atherosclerosis has been delayed because of the fear of causing embolic events while traversing the diseased portion of the artery with an angioplasty balloon catheter. Symptomatic carotid arteries often contain fresh or partially digested intraluminal thrombus. Before we cross certain carotid bifurcation lesions with angioplasty catheters, we deliver 100,000 to 200,000 units of urokinase in an attempt to digest loose thrombus. We have witnessed changes in the angiographic appearance of the diseased portion of the vessel after urokinase treatment, such as widening of the lumen, that suggest clot lysis. We present two patients who had symptomatic internal carotid artery stenosis. Angiography showed irregular narrowing of the internal carotid artery origin. One patient was selected for angioplasty instead of carotid endarterectomy because of severe cardiac risk factors. The other patient had major angiographic risk factors manifested by poor collateral circulation. The angiographic findings and history of transient ischemic attacks led us to suspect the presence of soft, loose plaque debris or thrombus in both cases. Therefore, we performed thrombolysis with urokinase before angioplasty. Repeat angiography showed widening of the arterial lumen and smoothing of the plaque profile. Subsequent angioplasty and stent placement were uneventful. Intraarterial thrombolysis can produce a change in the angiographic appearance of symptomatic atherosclerotic lesions of the cervical carotid artery bifurcation. Digestion of intralesional thrombus may provide a safer environment for deployment of endovascular remodeling devices by decreasing the likelihood of embolic phenomena. We believe thrombolysis should be done before angioplasty in select patients.

Aged↗
PubMed1995

Delayed recanalization of a cerebral arteriovenous malformation following angiographic obliteration with polyvinyl alcohol embolization.

BACKGROUND: The efficacy of embolization of cerebral arteriovenous malformations (AVMs) is presently being evaluated. Embolization of single pedicle AVMs may produce complete angiographic obliteration and has been suggested as the sole therapy for treating these lesions. METHODS: A 17-year-old female presented with a left intraventricular and intraparenchymal cerebral hemorrhage resulting from a 1 cm left posterior choroidal AVM. She subsequently underwent polyvinyl alcohol (PVA) embolization of the AVM with complete angiographic obliteration. RESULTS: At 9 months follow-up, no evidence of recanalization of the AVM nidus was seen. Two years later, recanalization of the nidus was seen; and the patient received radiosurgical treatment. The natural history of previously embolized AVMs is reviewed and the mechanisms for recanalization are discussed. CONCLUSION: We recommend that patients with angiographic obliteration of AVMs receive further treatment, preferably resection, or be followed with serial angiography.

Adolescent↗
PubMed1995

Implementation of region-of-interest fluoroscopy by using the road mapping mode of a real-time digital radiographic unit.

In region-of-interest (ROI) fluoroscopy, a filter is used to greatly attenuate the x-ray beam outside the ROI and digital image processing is used to equalize the displayed brightness. The method is applicable to real-time imaging procedures such as vascular interventions for which a high-quality image is essential only over an ROI (eg, near the catheter tip), whereas the noise-degraded periphery may be acceptable for visualizing landmarks. Use of ROI fluoroscopy can greatly reduce radiation exposure to the patient and to staff while image quality in the ROI is maintained or improved. Exposure reduction factors greater than 5 were demonstrated for coil placement in a canine aneurysm model by using standard digital angiographic equipment operating in the road mapping mode. Potential applications for which future work will determine the clinical acceptability of ROI fluoroscopy include many of the highest-dose interventional procedures, in addition to general gastrointestinal fluoroscopy.

Animals↗
PubMed1995

Angioplasty for symptomatic radiation-induced extracranial carotid artery stenosis: case report.

A patient with cervical lymphoma received chemotherapy and radiation to the neck. He later presented with crescendo transient ischemic attacks. Angiography demonstrated bilateral cervical carotid stenosis, which was presumed to be the result of previous radiation therapy. Percutaneous transluminal angioplasty with balloon dilation of the symptomatic lesion resulted in an immediate cessation of the patient's transient ischemic attacks. Nine months later, he developed a symptomatic cervical carotid stenosis of the contralateral carotid artery, which also was treated successfully with angioplasty, resulting in a good clinical outcome. The patient has experienced no further ischemic events in the 2 years after treatment.

Adult↗
PubMed1995

Lumbar discectomy: use of an epidural morphine sponge for postoperative pain control.

A technique for extended ambulatory epidural pain control after lumbar discectomy is described; preliminary results with 45 patients are reported; and alternative methods of narcotic analgesia are reviewed. In this technique, an absorbable gelatin sponge (Gelfoam, Upjohn Co., Kalamazoo, MI) is contoured to the laminotomy defect, placed in methylprednisolone acetate (40-80 mg), and then injected with 2 to 4 mg of preservative-free morphine (a small needle was used to fill the sponge). The sponge is placed over the defect before closure. A review of office and hospital records was conducted. The series consisted of 33 men and 12 women (mean age, 39 yr; range, 24-57 yr); records showed narcotic use in 34 patients (parenteral in 3) and work-related injuries in 14 patients. Thirty-three patients were ambulatory postoperatively on the day of surgery; all were ambulatory by postoperative day (POD) 1. On the day of surgery, 18 patients did not require any postoperative analgesics; on POD 1, 22 patients did not require analgesics. Six patients received parenteral narcotics; four received one dose only, and two had two or more doses. Thirty-one patients were discharged from the hospital on POD 1, and 10 were discharged POD 2. The other patients were discharged from the hospital on POD 3 (three patients) or POD 4 (one patient). When they were discharged, all patients received a limited supply of acetaminophen with codeine for pain control at home. After discharge, phone follow-up (at 1 week) and office follow-ups (at 3-5 weeks) revealed only one patient with more than mild discomfort. Three patients required one-time bladder catheterization, and one patient had presumed discitis 1 month postoperatively. In a control group who had undergone surgery 3 months previously, the average day of discharge had been POD 3.07; no control patient had been discharged on POD 1, and only 20% had been discharged on POD 2. This method provides effective, safe, and extended analgesia after lumbar discectomy.

Adult↗
PubMed1995

Balloon test occlusion of the internal carotid artery with hypotensive challenge.

PURPOSE: To evaluate the usefulness of provocative testing with hypotensive challenge during balloon test occlusion of the internal carotid artery before carotid sacrifice and to correlate tolerance of balloon test occlusion with clinical outcome after carotid artery sacrifice. METHODS: Forty-seven consecutive cases of balloon test occlusions performed at our institution during the past 4 years were retrospectively reviewed. Occlusion was performed under normotensive conditions with distal perfusion of heparinized saline for 20 minutes, or until a deficit was perceived. If 20 minutes of normotension was tolerated, hypotension was induced to two thirds of mean arterial pressure for 20 minutes, or until a deficit was perceived. RESULTS: Of 47 patients, 4 (9%) had deficits at normotension. Of the remaining 43 patients, 9 (21%) had deficits at hypotension. One patient with a positive hypotensive test occlusion underwent carotid artery sacrifice after extracranial-intracranial bypass without sequelae. In one of the 19 patients who clinically tolerated test occlusion with hypotension and had carotid sacrifice (surgical ligation of the intracranial carotid artery), a mild embolic stroke developed, probably from the giant carotid wall aneurysm. This patient fully recovered; MR imaging showed mild changes consistent with emboli distal to the aneurysm. Symptomatic complications were noted in 2 (4%) patients, and asymptomatic arterial dissections were noted in 3 (6%) patients. CONCLUSION: Balloon test occlusion with hypotensive challenge is safe, economical, and greatly increases the sensitivity of balloon test occlusion. The predictive value of a negative test is high. However, to determine the test's specificity compared with quantitative imaging, controlled trials will be necessary.

Adult↗
PubMed1995

Self-expanding nitinol stents in canine vertebral arteries: hemodynamics and tissue response.

PURPOSE: To evaluate the hemodynamics and tissue response associated with stent placement in low-flow-velocity arteries. METHODS: Six self-expanding nitinol stents (5.5 mm caliber) were implanted transfemorally within the proximal segments of vertebral arteries (2.5 mm diameter) in six adult dogs during anticoagulative protection. RESULTS: Control angiograms demonstrated patency and 20% dilatation of all stented arteries. One artery was partially thrombosed 1 week later and subsequently showed a 50% stenosis. Throughout the observation period (4 to 9 months after stenting), the other five arteries remained patent without significant narrowing (< or = 15%). Small cervical muscle branches originating from the vertebral arteries within the stented segments remained patent. No major branch occlusions of the vertebrobasilar system were detected. Stent migration or kinking did not occur. MR studies of the brain 4 months after implantation revealed no infarcted areas. These findings were confirmed with brain sections. Stented artery specimens showed delayed stent dilatation. A comparison of the total mean thickness of intima covering the five 30- to 40-mm stents removed at 4, 6, and 9 months showed no significant difference (338, 332, and 389 microns, respectively). Histologic findings verified the macroscopic impression of a thicker intima at the inner curve of the stented artery segments and at the junctions of the stent filaments. The shortest (10 mm) stent had the thinnest neointimal growth (155 microns). Stented vessels showed compression of the media with atrophy, but without necrosis or perforation. Scanning electron photomicrographs revealed intact endothelial cell linings with typical elongated cells. CONCLUSIONS: No significant risk of thromboembolic events exists after implanting these nitinol stents in nonatherosclerotic vertebral arteries in dogs. Thicker neointimal growth after stenting may result from either low wall shear stress with possible flow separation or from changes in the shape and size of the stent, or both.

Alloys↗
PubMed1995

Endovascular management of giant intracranial aneurysms.

The role of endovascular therapy for the treatment of giant aneurysms is presently being defined. Results derived from the endovascular treatment of giant aneurysms must be compared to the effectiveness and safety of operative treatment and the natural history of the disease. Most reports on the results of endovascular aneurysm treatment are of patients who have failed operative intervention or in whom operative intervention was not attempted because of their poor medical condition or other factors. Thus, the results of these techniques are from a high-risk subgroup. In a recent series of 19 giant aneurysms treated by a variety of techniques, including coils, balloons, and rapidly solidifying polymers, one death resulted after aneurysm rupture during the procedure (86). However, the major cause of mortality was cardiopulmonary complications within the first 2 weeks after the procedure. At present, it may be appropriate to reserve endovascular techniques for patients with no other reasonable therapeutic option. As experience with these techniques is gained, a comparison must be undertaken in a series of patients clinically equivalent to those in surgical series. Presently, the consensus is that endovascular therapy for giant aneurysms is efficacious for parent-vessel occlusion after balloon test occlusion to assess tolerance to sacrifice. Endosaccular occlusion is most effective if the aneurysm contains little thrombus, as determined by the size of the aneurysm seen on CT or MRI (87), as compared to the angiographic image. Small-necked aneurysms are particularly suited to coil occlusion if the aneurysm can be tightly packed. In wide-necked aneurysms, coil occlusion is possible, although the risk of parent-vessel occlusion is high. We often perform balloon test occlusion of the vessel before placing coils in wide-necked aneurysms. Failure of endovascular therapy after complete angiographic obliteration is based on recanalization or regrowth, resulting from device migration or remodeling at the junction of the device with the inflow tract and aneurysm wall, or by migration of the device into thrombus. The effect of aneurysm remnants after balloon or coil occlusion will be determined by long-term follow-up, as emphasized by Fox et al. (20, 63). Whenever there is an aneurysm remnant, some risk of subsequent hemorrhage exists (66). Further device refinement will enhance the safety and effectiveness of the endovascular treatment of giant aneurysms. The use of combined endovascular and conventional surgical techniques may be an increasingly important option in the treatment of giant aneurysms. Endosaccular packing of an aneurysm with occlusive material may not provide the ability to completely exclude the aneurysm from the circulation, and thus, will not necessarily prevent the process of regrowth. A further limitation of the currently implemented endovascular treatment of aneurysms is that fluoroscopy does not provide detailed information of aneurysm remnants due to the superimposition of occlusive materials, which may necessitate the development of new real-time imaging modalities for interventional procedure, such as intravascular ultrasound and ultrafast-sequence MRI.

Angioplasty↗
PubMed1994

Endovascular embolization and surgical excision for the treatment of cerebellar and brain stem hemangioblastomas.

Hemangioblastomas are histologically benign tumors that comprise 7%-10% of all posterior fossa lesions in the adult. Treatment of these lesions is often complicated by significant vascularity and difficulty of surgical resection in sensitive neural tissue, especially when the tumor has a significant solid component. We report the combined use of endovascular embolization of feeding pedicles and subsequent operative resection in two patients with solid hemangioblastomas of the cerebellum and brain stem. Preoperative embolization facilitated operative excision in sensitive neural areas and allowed complete surgical resection of tumors involving the lateral brain stem and cervicomedullary junction. Goals of preoperative embolization are control of inaccessible arterial supply and reduction of tumor vascularity.

Adult↗
PubMed1994

Retrieval of a Guglielmi detachable coil after unraveling and fracture: case report and experimental results.

Unraveling and fracture of electrolytically detachable coils (Guglielmi detachable coils) may occur during treatment of intracerebral aneurysms. Retrieval of the detached coil is difficult using existing snare technology, and the intraluminal coil may cause parent vessel thrombosis or distal embolization. We report a case of unraveling and fracture of a Guglielmi detachable coil that was successfully retrieved using a dual guidewire technique. The technique was evaluated in an in vitro model using 10 coils of varying sizes and diameters, and allowed successful coil retrieval in all trials.

Aged↗
PubMed1994

Combined use of stents and coils to treat experimental wide-necked carotid aneurysms: preliminary results.

PURPOSE: To develop a new technique to treat wide-necked side-wall aneurysms, combining the implantation of intraarterial stents with the endosaccular placement of coils. METHODS: Bilateral side-wall aneurysms were surgically created on the carotid arteries of four dogs. In each animal, Guglielmi detachable coils were introduced into one of the aneurysms after implantation of a balloon-expandable Strecker stent within the parent artery, adjacent to the aneurysm orifice. The contralateral aneurysms were treated with coils alone. RESULTS: In two dogs, one of the stented and both nonstented aneurysms remained partially open for 4 weeks after subtotal packing with coils. In another two dogs, tight aneurysm packing with coils resulted in complete occlusion of all four aneurysms. Bulging of the coil mass resulted in 30% to 75% narrowing of the nonstented parent arteries. At 4 and 5 weeks, significant stenosis resulting from reactive hyperplasia was observed in all stented carotid arteries. CONCLUSION: Based on these preliminary results, we conclude that Guglielmi detachable coils can be introduced into an aneurysm cavity through Strecker stents. The stents allow tighter packing of wide-necked aneurysms by preventing coils from migrating or bulging into the parent arteries.

Aneurysm↗
PubMed1994

Neuroendovascular training.

Neuroendovascular therapy in North America is performed by neuroradiologists and neurosurgeons. Representatives of both specialties are working together in defining training standards to apply to practitioners from either field so that patient care can be improved and complications minimized. Perhaps the ideal combination of therapists may be neuroradiologists with imaging skills collaborating with clinically skilled neurosurgeons.

Education, Medical, Graduate↗
PubMed1993

Vascular and endovascular neurosurgery.

Vascular lesions of the central nervous system such as aneurysms, arteriovenous malformations, tumors, and fistulas are responsible for the majority of intracranial hemorrhages seen in the United States. Microneurosurgical techniques have enabled neurosurgeons to effectively manage the majority of these lesions. Over the past 15 years, microcatheter based treatment modalities have evolved which permit access of the distal intracranial and spinal circulation by percutaneous cannulation of the femoral artery or vein. Technologic developments in polymer science and advances in hydrophilic coatings have produced microcatheters less than 1 mm in diameter capable of reaching deep within the nidus of arteriovenous malformations or into the body of a cerebral aneurysm. Numerous thrombogenic devices are available that can be delivered through microcatheters to permanently occlude cerebral vascular abnormalities. Catheter technology perfected in the coronary circulation for the management of atherosclerotic disease has been used to treat similar lesions of the extracranial and intracranial cerebral circulation. Cerebral circulation angioplasty for vasospasm has become an accepted technique, and superselective drug delivery is growing in popularity. This chapter reviews the recent literature in vascular and endovascular neurosurgery in an attempt to familiarize the reader with recent advances in the management of cerebrovascular disease.

Angioplasty, Balloon↗
PubMed1993

Endovascular treatment of cerebral aneurysms. Diagnosis and treatment.

The endovascular treatment of cerebral aneurysms provides an alternative intervention when the morbidity and mortality rates associated with conventional surgery are excessively high. In cases of giant posterior circulation aneurysms, the morbidity and mortality rates for endovascular treatment rival those of open surgical procedures. Although endovascular treatments provide promise for the treatment of all cerebral aneurysms, present modalities are inadequate to replace existing surgical therapies. The exponential growth in the development of new catheter technologies and thrombotic devices should eventually provide reproducible and permanent occlusion of aneurysm cavities with morbidity and mortality rates that are lower than those of open surgery. Proper intensive care unit management is crucial for success. Protection from rebleeding after endovascular treatment is not guaranteed. Numerous reports of delayed hemorrhage after thrombogenic device placement were described in this review. Remodeling of platinum coils after placement in an aneurysm cavity results in recanalization and possible growth of the aneurysm. It is difficult to consider these patients protected from rebleeding. Recently the Food and Drug Administration prohibited the distribution of silicone balloons in the United States. Negotiations are underway to regain use of these devices. Electrically detachable coils represent a significant advance in the arsenal for endovascular treatment, although this device will not replace open surgery. Future developments in endovascular devices should provide irreversible thrombosis of cerebral aneurysms regardless of their size, configuration, or position.

Adult↗