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Biomedical subjects

Henry H Woo

Publications and source records attributed to Henry H Woo.

15 recordsLinked to original sources
PubMed2006

Endovascular reconstruction with the Neuroform stent as monotherapy for the treatment of uncoilable intradural pseudoaneurysms.

OBJECTIVE: Intradural pseudoaneurysms have a malignant natural history and can be difficult to treat if parent vessel deconstruction is not feasible. These lesions often involve a long arterial segment and lack a defined saccular component that would safely accommodate the introduction of embolization coils. The current report describes the successful endovascular treatment of these lesions using a strategy of Neuroform stent reconstruction. METHODS: A retrospective review of the prospectively maintained Neuroform databases from our two institutions identified all intracranial aneurysms treated with the Neuroform stent alone, without embolization coils. The clinical charts, procedural data, and angiographic results were reviewed. RESULTS: Over a 38-month study period (10/02-2/06), 266 aneurysms were treated with the Neuroform stent. Of these, 10 were small "uncoilable" intradural pseudoaneurysms associated with subarachnoid hemorrhage. These lesions were treated using a strategy of endovascular stent reconstruction of the diseased vascular segment with one or more Neuroform stents (without concomitant coil embolization). Seven pseudoaneurysms were treated in the context of acute or subacute subarachnoid hemorrhage, and three were associated with a remote history of subarachnoid hemorrhage. Periprocedural complications occurred in two patients (clinically silent, intraprocedural thromboembolic event successfully treated with intra-arterial abciximab, symptomatic postprocedural stent thrombosis with successful thrombolysis, and excellent neurological recovery). Both complications occurred in patients with ruptured aneurysms and could be attributed to inadequate platelet inhibition at the time of the initial procedure. Follow-up conventional angiographic examinations were available for all 10 patients with pseudoaneurysms (1-18.5 mo; average, 9.0 mo). In nine cases, the aneurysms improved at follow-up, with either complete (n = 5) or near complete (n = 4) resolution. In one case, short-term follow-up (1 mo) demonstrated no significant change. No patient has rehemorrhaged after treatment. CONCLUSION: Endovascular Neuroform stent reconstruction represents an optimal strategy for the management of intradural pseudoaneurysms that require a constructive treatment strategy and are too small to accommodate the introduction of embolization coils. Nine out of 10 patients in the current series treated with this strategy demonstrated some degree of endovascular remodeling with either complete (n = 5) or partial (n = 4) angiographic resolution at follow-up. No rehemorrhages were encountered. Adequate antiplatelet therapy, even in the setting of acute subarachnoid hemorrhage, is prerequisite for the avoidance of thromboembolic complications.

Adolescent↗
PubMed2006

The role of neuroendovascular therapy for the treatment of brain arteriovenous malformations.

Neuroendovascular embolization represents a critical component of the multidisciplinary management of cerebral arteriovenous malformations. Safe and effective embolization may be performed only in the context of a well-designed, rational treatment plan that is fundamentally based on a clear understanding of the natural history of the lesion, as well as the cumulative risks of multimodality treatment. This article outlines the role of neuroendovascular embolization in arteriovenous malformation therapy with a specific emphasis on decision making in the context of formulating a treatment plan. The authors also provide a summary of the available embolic agents and their technical application, potential intraprocedural and periprocedural complications, and postprocedural management.

Blood Vessel Prosthesis↗
PubMed2005

Optical coherence tomography: a new method to assess aneurysm healing.

OBJECT: Aneurysmal subarachnoid hemorrhage affects approximately 10/100,000 people per year. Endovascular coil embolization is used increasingly to treat cerebral aneurysms and its safety and durability is rapidly developing. The long-term durability of coil embolization of cerebral aneurysms remains in question; patients treated using this modality require multiple follow-up angiography studies and occasional repeated treatments. METHODS: Optical coherence tomography (OCT) is an emerging imaging modality that uses backscattered light to produce high-resolution tomography of optically accessible biological tissues such as the eye, luminal surface of blood vessels, and gastrointestinal tract. Vascular OCT probes in the form of imaging microwires are presently available--although not Food and Drug Administration-approved--and may be adapted for use in the cerebral circulation. In this study the authors describe the initial use of OCT to make visible the neck of aneurysms created in a canine model and treated with coil embolization. Optical coherence tomography images demonstrate changes that correlate with the histological findings of healing at the aneurysm neck and thus may be capable of demonstrating human cerebral aneurysm healing. CONCLUSIONS: Optical coherence tomography may obviate the need for subsequent follow-up angiography studies as well as aid in the understanding of endovascular tissue healing. Data in this study demonstrate that further investigation of in vivo imaging with such probes is warranted.

Animals↗
PubMed2005

Stent-assisted angioplasty of intracranial vertebrobasilar atherosclerosis: midterm analysis of clinical and radiologic predictors of neurological morbidity and mortality.

BACKGROUND AND PURPOSE: Initial reports of stent-assisted angioplasty for intracranial vertebrobasilar atherosclerosis suggest this is a feasible treatment, but there have been little data regarding predictors of success or failure. We analyzed a series of patients for independent predictors of neurologic morbidity and mortality. METHODS: Patient charts and angiograms from 39 patients who underwent intracranial angioplasty and stent placement of vertebrobasilar stenoses were retrospectively reviewed to obtain clinical and detailed angiographic data on potential predictors of neurologic morbidity and mortality. Univariate analyses of these predictors were performed with either Fisher's exact test or simple logistic regression. Multivariate analysis was subsequently performed on the statistically significant predictors. RESULTS: Complete clinical data were obtained for 39 patients, and angiographic review was possible for 35 of them. Angiography revealed severe intracranial vertebral (n = 18), basilar (n = 15), or basilar and vertebral (n = 2) stenoses. Two patients (5.1%) died in the periprocedural period, nine patients (23.1%) had neurologic complications, and one patient (2.6%) had transient neurologic symptoms. Univariate analysis revealed female sex, diabetes, and failure of coumadin or heparin therapy were associated with neurologic morbidity, whereas female sex, Mori B lesion, and length-to-stenosis ratio were associated with mortality. The presence of diabetes was the only independent predictor of neurologic morbidity and mortality. CONCLUSION: Because of the limited number of patients available for analysis, the only independent predictor of neurologic morbidity and mortality was diabetes, but several other predictors showed trends that deserve further review in future series.

Angioplasty↗
PubMed2005

Y-configured dual intracranial stent-assisted coil embolization for the treatment of wide-necked basilar tip aneurysms.

OBJECTIVE: Despite advances in both the surgical and endovascular treatment of intracranial aneurysms, wide-necked basilar tip aneurysms (i.e., basilar tip aneurysms in which both posterior cerebral arteries emanate from the base of a wide-necked aneurysm) represent a subset of aneurysms that continues to pose technical challenges in treatment. We sought to demonstrate the safety and short-term durability of a novel dual stent-assisted coil embolization technique. METHODS: Two Neuroform stents (Boston Scientific/Target, Fremont, CA) were deployed in the posterior cerebral arteries and the basilar artery, one passing through the interstices of the other in a Y-configuration, thereby recreating an aneurysm neck and enabling safe coil delivery while preserving the parent vessels. RESULTS: Seven patients with unruptured, asymptomatic, wide-necked basilar tip aneurysms involving both posterior cerebral arteries and ranging in size from 7 to 20 mm underwent treatment with this stent-assisted coiling technique. Two stents were successfully deployed in six of the patients and one stent was successfully deployed in the seventh. One patient developed a transient internuclear ophthalmoplegia, and another experienced transient partial right oculomotor nerve palsy. All aneurysms had complete or near-complete embolization with the initial procedure. Follow-up angiography performed 6 months (six patients) and 1 year (one patient) after treatment demonstrated coil compaction and slight recanalization in one patient and recanalization requiring retreatment in another. All patients were neurologically intact at least 6 months after the initial procedure, as well as subsequent procedures, without clinical signs of subarachnoid hemorrhage. CONCLUSION: These initial technical and clinical results are highly encouraging, and this technique may significantly improve the endovascular treatment of intracranial aneurysms.

Balloon Occlusion↗
PubMed2004

A novel endovascular treatment of a wide-necked basilar apex aneurysm by using a Y-configuration, double-stent technique.

Wide-necked bifurcation aneurysms remain a formidable challenge to the neuroendovascular surgeon. A 36-year-old woman with a wide-necked basilar bifurcation aneurysm was unsuccessfully treated by endovascular methods, despite the use of the balloon-remodeling technique. Successful coiling was ultimately achieved by use of a Y-configuration double stent-assisted technique. This novel method of using self-expanding stents may represent a significant advance in the management of basilar apex and other bifurcation aneurysms.

Adult↗
PubMed2003

Use of a wedged microcatheter for curative transarterial embolization of complex intracranial dural arteriovenous fistulas: indications, endovascular technique, and outcome in 21 patients.

OBJECT: The aim of this study was to describe the application of a novel transarterial approach to curative embolization of complex intracranial dural arteriovenous fistulas (DAVFs). This technique is particularly useful in patients harboring high-grade DAVFs with direct cortical venous drainage or for whom transvenous coil embolization is not possible because of limited sinus venous access to the fistula site due to thrombosis or stenotic changes. METHODS: Twenty-three DAVFs in 21 patients were treated using a transarterial N-butyl cyanoacrylate (NBCA) embolization technique with the aid of a wedged catheter. In all patients, definitive treatment involved two critical steps: 1) a microcatheter was wedged within a feeding artery, establishing flow-arrest conditions within the catheterized vessel distal to the microcatheter tip; and 2) NBCA was injected under these resultant flow-arrest conditions across the pathological arteriovenous connection and into the immediate draining venous apparatus, definitively occluding the fistula. Patient data were collected in a retrospective manner by reviewing office and inpatient charts and embolization reports, and by directly analyzing all procedural and diagnostic angiograms. Eight patients presented with the principal complaint of tinnitus/bruit, five with intracranial hemorrhage, four with cavrnous sinus syndrome, and one each with seizures, ataxia, visual field loss, and hiccups. The parent (recipient) venous structure of the DAVFs in this study included 11 leptomeningeal veins, eight transverse/sigmoid sinuses, three cavernous sinuses, and one sphenoparietal sinus. The NBCA permeated the arteriovenous shunt, perifistulous network, and proximal draining vein in all DAVFs. Occlusion was confirmed on postembolization angiography studies. No complication occurred in any patient in this series. There has been no recurrence during a mean follow up of 18.7 months (range 2-46 months). CONCLUSIONS: Transarterial NBCA embolization with the aid of a wedged catheter in flow-arrest conditions is a safe and an effective treatment for intracranial DAVFs.

Adolescent↗
PubMed2002

Why not use a small incision to treat large hydroceles?

BACKGROUND: Operative treatment of large hydroceles generally requires a large incision. METHODS: A technique is described which permits a traditional Jaboulay's or Lord's repair to be done through a 3 cm incision. RESULTS: Twenty patients with large hydroceles were operated on from June 2000 to November 2001 using this technique and to date, only one patient has had a recurrence. There has been no occurrence of either scrotal wound infection or haematoma -formation. CONCLUSIONS: A hydrocele repair of the surgeon's choice can be done safely through a 3 cm incision.

Humans↗
PubMed2002

Interactive use of cerebral angiography and magnetoencephalography in arteriovenous malformations: technical note.

OBJECTIVE: To minimize the risks associated with treating cortical cerebral arteriovenous malformations (AVMs), we developed a technique combining functional imaging and cerebral angiography. The functional loci obtained by performing magnetoencephalography (MEG) are projected onto stereoscopic pairs of a stereotactically derived digital subtraction angiogram. The result is a simultaneous three-dimensional perspective of the angioarchitecture of an AVM and its relationship to the sensorimotor cortex. METHODS: Eight patients underwent multimodality brain imaging, including magnetic resonance imaging, functional mapping via MEG, and stereotactic angiography using a modified Compass fiducial system (Compass International, Rochester, MN). The coordinates derived by performing MEG were superimposed onto stereotactic, stereoscopic, angiographic pairs using custom-made distortion correction and coordinate transfer software. RESULTS: The magnetoencephalographic angiogram allowed simultaneous viewing of the angioarchitecture of the AVM nidus, the feeding vessels, and the draining veins and their relationship to the normal cerebral vasculature and functional cortex. This imaging technique was particularly valuable in identifying en passant vessels that supplied functional cortex and was used during the treatment of these lesions. CONCLUSION: The techniques of MEG and cerebral angiography were combined to provide simultaneous viewing of both modalities in a three-dimensional perspective. This technique can aid in risk stratification in the management of patients with cerebral AVMs. In addition, this technique can facilitate the selective targeting of vessels, thus potentially reducing the risks associated with embolization of these formidable lesions.

Adolescent↗
PubMed2002

Treatment of giant intracranial aneurysms with saphenous vein extracranial-to-intracranial bypass grafting: indications, operative technique, and results in 29 patients.

OBJECTIVE: The treatment of giant intracranial aneurysms is a challenge because of the limitations and difficulty of direct surgical clipping and endovascular coiling. We describe the indications, surgical technique, and complications of saphenous vein extracranial-to-intracranial bypass grafting followed by acute parent vessel occlusion in the management of these difficult lesions. METHODS: Between January 1990 and December 1999, 29 patients with giant intracranial aneurysms underwent 30 saphenous vein bypass grafts followed by immediate parent vessel occlusion. There were 11 men and 18 women with a mean follow-up period of 62 months. Twenty-five patients harbored aneurysms involving the internal carotid artery, 2 had middle cerebral artery aneurysms, and 2 had aneurysms in the basilar artery. Serial cerebral or magnetic resonance angiograms were obtained to assess graft patency and aneurysm obliteration. RESULTS: All 30 aneurysms were excluded from the cerebral circulation, with 28 vein grafts remaining patent. Two patients had graft occlusions: one because of poor runoff and the other because of misplacement of a cranial pin during a bypass procedure on the contralateral side. Other surgical complications included one death from a large cerebral infarction, homonymous hemianopsia from thrombosis of an anterior choroidal artery after internal carotid artery occlusion, and temporary hemiparesis from a presumed perforator thrombosis adjacent to a basilar aneurysm. CONCLUSION: With appropriate attention to surgical technique, a saphenous vein extracranial-to-intracranial bypass followed by acute parent vessel occlusion is a safe and effective method of treating giant intracranial aneurysms. A high rate of graft patency and adequate cerebral blood flow can be achieved. Thrombosis of perforating arteries caused by altered blood flow hemodynamics after parent vessel occlusion may be a continuing source of complications.

Cerebral Arteries↗
PubMed2002

Role of frameless stereotaxy in the surgical treatment of cerebral arteriovenous malformations: technique and outcomes in a controlled study of 44 consecutive patients.

OBJECTIVE: To describe a frameless stereotactic technique used to resect cerebral arteriovenous malformations (AVMs) and to determine whether frameless stereotaxy during AVM resection could decrease operative times, minimize intraoperative blood losses, reduce postoperative complications, and improve surgical outcomes. METHODS: Data for 44 consecutive patients with surgically resected cerebral AVMs were retrospectively reviewed. The first 22 patients underwent resection without stereotaxy (Group 1), whereas the next 22 patients underwent resection with the assistance of a frameless stereotaxy system (Group 2). RESULTS: The patient characteristics, AVM morphological features, and percentages of preoperatively embolized cases were statistically similar for the two treatment groups. The mean operative time for Group 1 was 497 minutes, compared with 290 minutes for Group 2 (P = 0.0005). The estimated blood loss for Group 1 was 657 ml, compared with 311 ml for Group 2 (P = 0.0008). Complication rates, residual AVM incidences, and clinical outcomes were similar for the two groups. CONCLUSION: Frameless stereotaxy allows surgeons to 1) plan the optimal trajectory to an AVM, 2) minimize the skin incision and craniotomy sizes, and 3) confirm the AVM margins and identify deep vascular components during resection. These benefits of stereotaxy were most apparent for small, deep AVMs that were not visible on the surface of the brain. Frameless stereotaxy reduces the operative time and blood loss during AVM resection.

Adolescent↗
PubMed2002

A comparison of techniques for eliciting patient preferences in patients with benign prostatic hyperplasia.

PURPOSE: We compared the Health Utility Index (HUI), EuroQol (EQ-5D) and time trade-off methods to identify the most suitable technique for collecting preference data in a clinical trial of patients with benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: A total of 29 men with symptomatic BPH were interviewed by a single trained interviewer who collected demographic data and administered EQ-5D and time trade-off questionnaires. Participants self-administered the HUI and a symptom severity index, the International Prostate Symptom Score (I-PSS) questionnaire. Utility values for current patient health states obtained from the HUI, EQ-5D and time trade-off questionnaires were compared and their relationship with I-PSS data was examined using Spearman's correlation coefficients. Administration time and patient assessments of the relevance of the questions were also compared for the 3 methods. RESULTS: Although mean utility values for HUI, EQ-5D and 1-year time trade-off were similar, only utility values elicited using time trade-off with a 1-year time frame significantly correlated with symptom scores. The 1 and 10-year time trade-off derived values were reasonable predictors of the I-PSS with multiple correlation coefficient values of 0.379 and 0.265, respectively. All participants indicated that the HUI and EQ-5D were appropriate for assessing BPH, while approximately 10% considered time trade-off questions irrelevant. Average completion time for the HUI, time trade-off and EQ-5D questionnaires was 31, 25 and 10 minutes, respectively. CONCLUSIONS: Because only time trade-off resulted in utility values that significantly correlated with symptom scores, we recommend its use for estimating utility in clinical trials of BPH.

Adult↗