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Biomedical subjects

F T Charbel

Publications and source records attributed to F T Charbel.

At least 19 recordsLinked to original sources
PubMed2002

Spontaneous disappearance of vein of galen malformation and posterior fossa venous pouch.

Cerebrovascular anomalies remain an issue of controversy regarding diagnosis, classification, and treatment. We report the first case of total and asymptomatic regression and disappearance of a vein of Galen malformation associated with a posterior fossa venous pouch. Different aspects of the vein of Galen are discussed together with emphasis on the underlying mechanisms of spontaneous thrombosis and regression.A 4-month-old boy presented with macrocrania and signs of intracranial hypertension. Computerized tomography disclosed two masses, the first was a giant aneurysmal dilatation in the posterior fossa, and the second was a gigantic pouch at the level of the vein of Galen. Hydrocephalus was treated by ventriculo-peritoneal shunting. Two months later, the shunt was revised, and posterior fossa was explored without active treatment. Both abnormalities regressed spontaneously. No recurrence occurred, and the child remained neurologically intact. Total disappearance of the masses as well as normal brain and cerebrovascular anatomy were confirmed by angiography, MRI, and MRA. Over a follow-up period of 17 years, the patient did not develop complications. He had perfect clinical tolerance and resumed a normal life.

Cerebral Veins↗
PubMed2001

Guglielmi detachable coiling for intracranial aneurysms: the story so far.

Spontaneous rupture of cerebral aneurysms typically results in subarachnoid hemorrhage. The primary goal of treatment of cerebral aneurysms is to prevent future rupture. Surgical clipping had been the mainstay of treatment of both ruptured and unruptured cerebral aneurysms. In 1991, Guglielmi detachable coil (GDC) embolization was introduced as an alternative method for treating selected patients with aneurysm. The goal of the treatment is prevent the flow of blood into the aneurysm sack by filling the aneurysm with coils and thrombus. Theoretically, there are several advantages of GDC over surgery. These procedures are performed under general anesthesia with the standard transfemoral approaches used in diagnostic angiography. Since its inception, GDC embolization has evolved as a result of both clinical experience and the introduction of technological improvements. We are now better at selecting aneurysms appropriate for coiling, which also have wide necks. Advances in GDC technology have also improved this method of treatment. Over the last several years, the number of coil sizes has been increased, multidimensional coils allowing safer initial coil placement have become available, and, more recently, softer coils have been introduced. Our current approach is to have both surgical and endovascular options for patients.

Cerebral Hemorrhage↗
PubMed2001

Closed chest hypothermic circulatory arrest for complex intracranial aneurysms.

BACKGROUND: Recent advances in techniques of cardiopulmonary bypass permitted hypothermic circulatory arrest (HCA) using groin cannulation with the chest closed (CC-HCA) and without direct access to the heart. Herein we describe our experience with this technique for complex intracranial aneurysms. METHODS: Between 1992 and 1999, 16 patients (4 men and 12 women) with a mean age of 52 years (range 32 to 61 years) with complex intracranial aneurysms underwent resection or clipping of their aneurysms at our institution using the technique of CC-HCA and groin cannulation. Groin access was obtained with 16F to 19F arterial and 18F to 20F venous cannulas placing the tips at the aortoiliac and atriocaval junctions, respectively. Patients were cooled to a nasopharyngeal temperature of 16 degrees C. RESULTS: Mean circulatory arrest time was 32 minutes. No patient required conversion to standard sternotomy and central cannulation. There were no intraoperative deaths. The 30-day hospital mortality was 2 of 16 patients (12%). Of the 14 surviving patients (88%), 1 developed bilateral third nerve palsy and another left hemiparesis that improved on follow-up. Both were discharged to an extended care facility and continued to do well at home after discharge. Two patients developed deep venous thrombosis postoperatively and required anticoagulation. All patients continued to do well at a mean follow-up of 42 months. CONCLUSIONS: The less invasive technique of CC-HCA through groin cannulation avoids complications associated with a sternotomy, is safe and is associated with little morbidity, reduced operative time, and early hospital discharge and rehabilitation.

Adult↗
PubMed2001

Bedside external ventricular drain placement for the treatment of acute hydrocephalus.

The purpose of this retrospective study was to evaluate the results of external ventricular drain (EVD) placement for the management of hydrocephalus. We present our experience with 103 consecutive cases over one year, 56 of which had subarachnoid hemorrhage (SAH). Short tunnel ventriculostomy was performed at the bedside in the neurosurgical intensive care unit (NSICU), using sterile technique. Long-term care included meticulous site care by a dedicated NSICU nurse, daily cultures and prophylactic antibiotics. The average duration of EVD was 10.7 days (range 1-28 days). There was one case of positive cerebrospinal fluid (CSF) culture. Additional complications included one small intraparenchymal hematoma and two cases of EVD disconnection. No patient died form EVD-associated complications. No rebleed from aneurysmal SAH was seen. There was no correlation between the duration of EVD and infection. We conclude that placement of short EVD in the NSICU is safe and can be maintained for the required duration of treatment with minimum infection rate.

Acute Disease↗
PubMed2001

Computerized hemodynamic evaluation of the cerebral circulation for bypass.

This article describes details of the application of computer modeling of cerebral blood circulation. A brief review of the different computer modeling techniques and the current models used today for predicting surgical options for bypass surgery are presented. The use of phase contrast MR for estimating intracranial flow rates makes these models even more accurate. Two case studies are presented with computer simulation results with verification of predicted outcome both clinically and from actual flow of measurements.

Brain↗
PubMed2000

Hemodynamics of in-tandem stenosis of the internal carotid artery: when is carotid endarterectomy indicated?

BACKGROUND: Recent publications have pointed out the importance of evaluating patients with in-tandem stenosis and in particular the association of moderate stenosis of the extracranial internal carotid artery (ICA) with moderate or severe stenosis of the intracranial internal carotid artery. Such evaluations are needed in symptomatic patients before planning carotid endarterectomies because observations have shown that in some cases the removal of an extracranial lesion does not necessarily improve these symptoms. This paper examines the hemodynamic effects of in-tandem stenosis in the internal carotid artery. METHODS: Equations describing flow in arteries are modified to accommodate two regions of stenosis in tandem. An equivalent value of stenosis is derived such that two stenoses in tandem behave as a single stenosis with similar hemodynamic properties. The solution to this problem is solved mathematically and this was used to analyze the observations made in five studies published on in-tandem stenosis of the internal carotid artery. RESULTS: Equivalent stenoses for various values of extracranial and intracranial stenoses are presented. It was found that two stenotic lesions in tandem are not equivalent to a simple summation of both values. A graphical solution is presented to show the hemodynamic effects of both stenoses. CONCLUSIONS: The most critical determinant of hemodynamic compromise when two lesions are in tandem is the larger one. Hence removal of a more proximal lesion may have little effect on a larger distal lesion if the symptoms are due to hypoperfusion. It is important that one distinguish between hypoperfusion and thromboembolic causes of the symptoms. No conclusions about the risk of thromboembolic events after a carotid endarterectomy in the setting of a distal stenosis can be made from this study.

Aged↗
PubMed2000

Surgery following endovascular coiling of intracranial aneurysms.

BACKGROUND: Surgery for intracranial aneurysms that have been treated by endovascular coiling is a new challenge for neurosurgeons and the need for it will undoubtedly continue to increase. The indications for, timing, and technique of surgery in our experience are described. METHODS: We have reviewed our experience with 11 patients who underwent surgery following endovascular coiling with Guglielmi detachable coils (GDCs) of an aneurysm. We analyzed the indications for surgery, surgical techniques used, and patient outcome. RESULTS: There were nine female and two male patients. The mean age was 49 years (range 13 to 67 years). The intervals between coiling and surgery were 1, 2, 3, 4, 7, 7, 10, and 14 days, 6 weeks, 2, 18, and 25 months. The indications for surgery were partial treatment (3), growth of residual neck (2), persistent mass effect of a giant aneurysm (1), mass effect from the coil ball (2), coil migration (2), and coil protrusion with embolic event (1). The coils were removed at the time of surgery from 9 of 11 aneurysms before clipping. In two cases it was possible to place a clip across the neck of the aneurysm without removing the coils, as the coils no longer occupied the neck. There were two permanent deficits directly related to the endovascular procedures. Two other patients who presented with subarachnoid hemorrhage had residual neurological deficits post surgery and one patient with a giant aneurysm had persistent visual loss. CONCLUSION: Surgery remains a viable option at any time for treating aneurysms that have been previously treated by GDC placement. The operative approach is determined by the need for coil removal and the duration since coiling.

Adolescent↗
PubMed2000

Brain tissue PO(2), PCO(2), and pH during cerebral vasospasm.

BACKGROUND: The purpose of the present study was to assess brain tissue monitoring for detection of ischemia due to vasospasm in aneurysmal subarachnoid hemorrhage (SAH) patients. METHODS: After obtaining informed consent, a burr hole was made in 10 patients and a Neurotrend 7 probe was inserted ipsilateral to the region of SAH. In eight patients the probe was inserted during surgery for clipping the aneurysm and in two patients the probe was inserted in the neurosurgery ICU. Brain tissue gases and pH were collected over 6-hour periods for 7 to 10 days until the termination of monitoring. The onset of vasospasm was confirmed by angiography and xenon computed tomography (Xe/CT) cerebral blood flow studies. RESULTS: Seven patients did not develop vasospasm during monitoring and were considered as controls. In this group, brain tissue oxygen pressure (PO(2)) remained above 20 mmHg, carbon dioxide pressure (PCO(2)) stabilized at 40 mmHg and pH remained between 7.1 and 7.2. In three patients who developed vasospasm during monitoring, PO(2) was not different from the control group. However, PCO(2) increased to 60 mmHg and pH decreased to 6.7 (p < 0.001). CONCLUSION: In this study, patients with SAH who developed vasospasm had significantly lower brain tissue pH and higher PCO(2) compared to controls. However, there was no significant change in PO(2) levels associated with vasospasm. Brain tissue monitoring can provide an indication of ischemia during vasospasm.

Aged↗
PubMed2000

Techniques of coiling cerebral aneurysms.

BACKGROUND: More than 200 aneurysms have been coiled at the UIC Medical Center within the last 5 years. We describe in detail the technical factors that increase the chance of complete occlusion of a cerebral aneurysm with coils. Aneurysms selected for coiling have good geometry or are in a location that is difficult to reach surgically. Patients with medical conditions that preclude surgical treatment may also undergo coiling. METHODS: Patients with aneurysms, either ruptured or unruptured, are treated under general anesthesia, fully anticoagulated and deeply paralyzed. Coiling is done under simultaneous biplane roadmapping. After the first coil has created a mesh, the aneurysm is densely packed with soft coils of decreasing diameter, until no more coils can be deployed into the aneurysm. RESULTS: The morbidity and mortality rates associated with the coiling procedure have continuously decreased over the last 5 years. The morphological outcomes have improved, due to extensive use of the remodeling technique and to advancements in materials, such as refinements in the coils themselves or the availability of over-the-wire balloon catheters in different sizes and hydrophilic wires with complex tip configurations. Twenty-one percent of the aneurysms were considered to be incompletely occluded immediately after coiling. Of this group, one-third of the aneurysms were found to be completely occluded on follow-up angiograms by 6 months; these have remained occluded. One-third were more than 95% occluded after the coiling procedure; in these patients, the dome was completely occluded, but there was a small neck remnant, which has remained stable in all patients on control angiograms obtained at 6 months and 1, 2, and 4 years; none have rebled. These patients are followed medically. The remaining one-third of the aneurysms in this subgroup were less than 95% occluded, although the dome was completely thrombosed. None of them have rebled, but the neck remnant in most has regrown over a period ranging from 6 months to 2 years. These patients have undergone a second treatment-either surgical clipping, permanent occlusion of the parent vessel, or repeat coiling using the remodeling technique. The overall rebleeding rate of incompletely occluded aneurysms is extremely low (less than 1%). CONCLUSION: The low morbidity and mortality rates and the good morphological outcome obtained in most cases make coiling a reasonable alternative to surgical clipping in properly selected cases.

Embolization, Therapeutic↗
PubMed2000

Improved phase-contrast flow quantification by three-dimensional vessel localization.

In this paper, a method of three-dimensional (3D) vessel localization is presented to allow the identification of a vessel of interest, the selection of a vessel segment, and the determination of a slice orientation to improve the accuracy of phase-contrast magnetic resonance (PCMR) angiography. A marching-cube surface-rendering algorithm was used to reconstruct the 3D vasculature. Surface-rendering was obtained using an iso-surface value determined from a maximum intensity projection (MIP) image. This 3D vasculature was used to find a vessel of interest, select a vessel segment, and to determine the slice orientation perpendicular to the vessel axis. Volumetric flow rate (VFR) was obtained in a phantom model and in vivo using 3D localization with double oblique cine PCMR scanning. PCMR flow measurements in the phantom showed 5. 2% maximum error and a standard deviation of 9 mL/min during steady flow, 7.9% maximum error and a standard deviation of 13 mL/min during pulsatile flow compared with measurements using an ultrasonic transit-time flowmeter. PCMR VFR measurement error increased with misalignment at 10, 20, and 30 degrees oblique to the perpendicular slice in vitro and in vivo. The 3D localization technique allowed precise localization of the vessel of interest and optimal placement of the slice orientation for minimum error in flow measurements.

Blood Flow Velocity↗
PubMed2000

Hypoxic brain tissue following subarachnoid hemorrhage.

BACKGROUND: Subarachnoid hemorrhage can lead to cerebral ischemia and irreversible brain injury. The purpose of this study was to determine whether subarachnoid hemorrhage produces changes in brain tissue oxygen pressure, carbon dioxide pressure, or pH during surgery for cerebral aneurysm clipping. METHODS: After institutional review board approval and patient consent, 30 patients undergoing craniotomy for cerebral aneurysm clipping were studied, 15 without and 15 with subarachnoid hemorrhage. Patients with subarachnoid hemorrhage were prospectively separated into groups with modest (Fisher grade 1 or 2; n = 8) and severe bleeds (Fisher grade 3; n = 7). After a craniotomy, a probe was inserted into cortex tissue supplied by the artery associated with the aneurysm. Baseline measures were made in the presence of a 4% end-tidal desflurane level. The end-tidal desflurane level was increased to 9% before clipping of the aneurysm, and a second tissue measurement was made. RESULTS: The median time of surgery after subarachnoid hemorrhage was 2 days, ranging from 1 to 13 days. During baseline anesthesia, brain tissue oxygen pressure was 17+/-9 mm Hg (mean +/- SD) in control patients, 13+/-9 mm Hg in those with Fisher grade 1 or 2 hemorrhage, and 7+/-6 mm Hg in those with Fisher grade 3 hemorrhage (P<0.05 compared with control). Brain tissue pH was 7.10+/-0.10 in control patients, 7.14+/-0.13 in those with Fisher grade 1 or 2 hemorrhage, and 6.95+/-0.18 in those with with Fisher grade 3 hemorrhage (P<0.05). At a 9% end-tidal desflurane level, brain tissue oxygen pressure increased to 19+/-9 mm Hg and brain tissue pH increased to 7.11+/-0.11 in patients with Fisher grade 3 hemorrhage (P<0.05 for both increases). CONCLUSION: These results show that subarachnoid hemorrhage can significantly decrease brain tissue oxygen pressure and pH related to the severity of the bleed. Increasing the desflurane concentration to 9% increased brain tissue oxygen pressure in all patients and brain tissue pH in patients with subarachnoid hemorrhage with baseline acidosis.

Adult↗
PubMed2000

What percentage of surgically clipped intracranial aneurysms have residual necks?

OBJECTIVE: To determine the angiographically proven rate and persistence of occlusion of intracranial aneurysms after surgical clipping as reported in the literature. This should establish a basis for comparing surgery with new endovascular methods of treatment. METHODS: We reviewed the literature published during the period from 1979 through 1999, dividing the articles into two groups. The first group of articles reported patients undergoing surgical treatment with immediate postoperative angiography. The second group of articles documented symptomatic recurrence or regrowth of aneurysms that were surgically treated previously. The data from these articles are presented for analysis. RESULTS: During the period 1979 to 1999, six series of patients undergoing surgical treatment of aneurysms with immediate postoperative angiography were reported. These reported series comprised a total of 1,397 patients, of whom 1,370 underwent postoperative angiography demonstrating 1,569 clipped aneurysms. Residual filling was found in 82 aneurysms (5.2%) on postoperative angiography. Of the 1,370 patients, only 124 patients with 169 aneurysms were reported to have had any long-term angiographic follow-up. The second group consisted of 226 patients representing six reported groups of patients, who either presented up to 24 years after aneurysm clipping with recurrent symptoms of hemorrhage or mass effect, or had important findings on intraoperative and postoperative angiograms. CONCLUSION: The lack of information regarding both the frequency of residual filling or regrowth and long-term angiographic follow-up of patients with surgically treated aneurysms makes meaningful comparison between surgical treatments and new treatment methods for intracranial aneurysms difficult or impossible. Detailed analysis with high-quality angiography should be performed to determine the success of surgical treatment.

Cerebral Angiography↗
PubMed2000

Giant anterior communicating artery aneurysm infiltrated with a primary cerebral lymphoma: case report.

OBJECTIVE AND IMPORTANCE: Central nervous system lymphomas exhibit angiotropic characteristics. Nevertheless, direct association with an intracranial aneurysm is very rarely reported. We present a case of a giant aneurysm infiltrated with a large cell non-Hodgkin's lymphoma. The incidence of primary central nervous system lymphoma is increasing, and similar cases may become more frequent in the future. CLINICAL PRESENTATION: A 65-year-old man had presented with a giant anterior cerebral artery aneurysm, new onset of seizures, aphasia, and hemiparesis. The aneurysm was treated with Guglielmi detachable coils. Six months later, the patient exhibited fever and neurological deterioration. Magnetic resonance images suggested an enhancing lesion posterior to the neck of the aneurysm. Antibiotic treatment given elsewhere was unsuccessful. INTERVENTION: A craniotomy for a suspected abscess was performed, with removal of the aneurysm and clipping of the neck. The aneurysm sac appeared to be filled with thrombus and pus. The results of aerobic, anaerobic, and fungal cultures were negative. Postoperative magnetic resonance images demonstrated a residual mass, posterior to the aneurysm within the striatum and the internal capsule. Histological examination of the aneurysm wall revealed a large B-cell lymphoma. The diagnosis was confirmed by a stereotactic biopsy. Radiation therapy resulted in a transient decrease in the size of the lesion. CONCLUSION: Although the tumor was not apparent on the initial imaging studies, it may have been the cause of the patient's presenting symptoms. Infiltration of the aneurysm wall by the lymphoma also raises the possibility of a causal relationship. As the incidence of primary central nervous system lymphoma is reported to be on the increase, awareness this uncommon association of an aneurysm and malignant lymphoma is of value.

Aged↗
PubMed1999

What does measurement of brain tissue pO2, pCO2 & pH add to neuromonitoring?

In this paper the rationale behind utilizing the brain tissue measurements of oxygen, carbon dioxide, pH and temperature is evaluated in the context of ischemia. These parameters were measured using an intraparenchymal multi-parametric brain tissue monitor (Paratrend 7). The need to establish the relevance of this type of monitoring becomes acute as further experience is gained using this kind of technology. Our experience with such a device is presented and is illustrated with two clinical cases. The potential caveats and areas of possible future work are also delineated.

Acute Disease↗
PubMed1999

Juxtaorbital en plaque meningiomas. Report of four cases and review of literature.

Juxtaorbital spheroid wing or ridge meningiomas are the most common of the basal meningiomas. These are at times meningiomas en plaque, which in most patients do not have significant intracranial component. This article reviews the literature on en-plaque meningiomas and discusses the role of MR imaging and CT in the diagnosis of en-plaque meningiomas of the paraorbital region. The role of fat-suppression, gadolinium-enhanced, T1-weighted MR imaging is emphasized.

Adult↗
PubMed1999

Measurement of ischemia by changes in tissue oxygen, carbon dioxide, and pH.

BACKGROUND: We evaluated the ability of brain tissue oxygen pressure (PO2), carbon dioxide pressure (PCO2), and pH to detect regional ischemia produced by temporary brain artery occlusion, compared with a group without artery occlusion. METHODS: Patients undergoing craniotomy for cerebrovascular surgery were recruited for this study. A 0.5-mm-diameter probe was inserted into brain tissue to measure PO2, PCO2, and pH continuously. Group 1 (n = 15) did not receive brain artery occlusion during their surgical procedure. In Group 2, brain artery occlusion was produced for aneurysm clipping (n = 10) or extracerebral to intracerebral artery bypass (n = 3). Mean arterial pressure was maintained above 90 mmHg in both groups. Measurements were made after artery occlusion or sham treatment and compared with baseline. RESULTS: Under baseline conditions, tissue PO2, PCO2, and pH were not different between the groups. In Group 2, brain artery occlusion for a median time of 7 minutes (range, 2-48 min) significantly decreased PO2 and pH and increased PCO2 compared with baseline. There were no significant changes in Group 1. During artery occlusion, PO2 decreased below 10 mmHg and/or pH decreased below 7.0 in 8 of 13 patients. CONCLUSIONS: Regional brain ischemia can be consistently detected and treated by monitoring tissue metabolism. It will be necessary in the future to identify critical levels and duration of decreases in PO2 and pH that lead to irreversible neuronal injury.

Brain↗