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PubMed2004

PV1 is a key structural component for the formation of the stomatal and fenestral diaphragms.

PV1 is an endothelial-specific integral membrane glycoprotein associated with the stomatal diaphragms of caveolae, transendothelial channels, and vesiculo-vacuolar organelles and the diaphragms of endothelial fenestrae. Multiple PV1 homodimers are found within each stomatal and fenestral diaphragm. We investigated the function of PV1 within these diaphragms and their regulation and found that treatment of endothelial cells in culture with phorbol myristate acetate (PMA) led to upregulation of PV1. This correlated with de novo formation of stomatal diaphragms of caveolae and transendothelial channels as well as fenestrae upon PMA treatment. The newly formed diaphragms could be labeled with anti-PV1 antibodies. The upregulation of PV1 and formation of stomatal and fenestral diaphragms by PMA was endothelium specific and was the highest in microvascular endothelial cells compared with their large vessel counterparts. By using a siRNA approach, PV1 mRNA silencing prevented the de novo formation of the diaphragms of caveolae as well as fenestrae and transendothelial channels. Overexpression of PV1 in endothelial cells as well as in cell types that do not harbor caveolar diaphragms in situ induced de novo formation of caveolar stomatal diaphragms. Lastly, PV1 upregulation by PMA required the activation of Erk1/2 MAP kinase pathway and was protein kinase C independent. Taken together, these data show that PV1 is a key structural component, necessary for the biogenesis of the stomatal and fenestral diaphragms.

Animals↗
PubMed1997

Fenestrated oculomotor nerve caused by internal carotid-posterior communicating artery aneurysm: case report.

OBJECTIVE AND IMPORTANCE: The fenestrated oculomotor nerve associated with the internal carotid-posterior communicating artery aneurysm is very rare. CLINICAL PRESENTATION: A 48-year-old woman had a history of subarachnoid hemorrhage caused by a ruptured right middle cerebral artery aneurysm, which was wrapped with good postoperative course. Twenty years later, the patient suffered frontal headache with a mild oculomotor nerve paresis in the right side. Follow-up neuroimaging studies demonstrated a de novo right internal carotid-posterior communicating artery aneurysm. INTERVENTION: The aneurysm was exposed and clipped via a right pterional route. The fenestrated oculomotor nerve associated with the aneurysm was confirmed at surgery. CONCLUSION: We speculated that the fenestration was most likely caused, by the growth of the aneurysm.

Carotid Artery Diseases↗
PubMed1998

Pars interarticularis fenestration in the treatment of foraminal lumbar disc herniation: a further surgical approach.

OBJECTIVE: A new surgical approach to foraminal disc herniation is proposed. METHODS: The procedure was performed in 28 patients during a span of 3 years. The herniation was purely foraminal in 18 patients and mainly foraminal with a definite extraforaminal component in the other 10 patients. Surgical treatment was offered only after 6 weeks of therapy with anti-inflammatory drugs and strict bed rest had proved to be ineffective. SURGICAL TECHNIQUE: To unroof the foraminal compartment, an ovoid fenestration (10 x 5 mm) is cut, with its major longitudinal axis at the level of the pars interarticularis, just medially and slightly off-center under the lateral isthmic notch, i.e., below the pedicle projection. This fenestration exposes the foraminal root compressed by the herniated disc, which can be easily removed. RESULTS: Treatment was successful in all patients, with swift remission of pain and only mild postoperative discomfort. All patients resumed their occupations as usual within 10 to 30 days after the operation, according to type of work. Mean follow-up is 24 months (range, 12-36 mo), without any return of pain. CONCLUSION: We propose pars interarticularis fenestration because it spares, with minimal bone removal, the facet joints and the anatomic continuity of the pars interarticularis, yet properly exposes the foraminal compartment both medially and laterally and thereby permits optimal removal of the disc herniation.

Adult↗
PubMed1999

Does lamina terminalis fenestration reduce the incidence of chronic hydrocephalus after subarachnoid hemorrhage?

OBJECTIVE: The incidence of chronic hydrocephalus requiring cerebrospinal fluid shunting was analyzed for a prospective series of 52 consecutive patients with ruptured cerebral aneurysms who underwent fenestration of the lamina terminalis during early microsurgical aneurysm repair. We hypothesized that, by creating an anterior ventriculocisternostomy, fenestration of the lamina terminalis would facilitate cerebrospinal fluid dynamics and decrease the risk of subsequent hydrocephalus. METHODS: Patients were enrolled according to the following criteria: 1) age more than 40 years; 2) admission Hunt and Hess Grade 2 to 4; 3) initial subarachnoid hemorrhage severity of Fisher Grade 3 or 4; and 4) early microsurgical repair of an anterior circulation aneurysm. RESULTS: The mortality rate in this series was 9.6%. Of the 47 surviving patients, 32 (68%) were discharged with a Glasgow Outcome Scale score of 5, 10 (21%) with a Glasgow Outcome Scale score of 4, and 5 (11%) with a Glasgow Outcome Scale score of 3. The follow-up period ranged from 12 to 60 months. Chronic hydrocephalus was radiographically and clinically evident in 3.8% of the total population. Shunt surgery was performed for two patients who exhibited symptoms resulting from hydrocephalus, corresponding to 4.2% of the surviving patients. CONCLUSION: Estimates from the most recently published studies indicate that an incidence of chronic post-subarachnoid hemorrhage hydrocephalus (requiring shunt surgery) of 15 to 20% is representative for an average contemporary population of patients with aneurysmal subarachnoid hemorrhage. The lower incidence of chronic hydrocephalus observed in this series possibly reflects the favorable effect of lamina terminalis fenestration on cerebrospinal fluid dynamics.

Adult↗
PubMed1987

Reconstruction of orbital wall fenestrations with polyglactin 910 film.

Medial orbital wall fenestrations were created bilaterally in 16 adult cats. The fenestrations were reconstructed with polyglactin 910 film, Dacron-reinforced silicone sheeting, or no implant. Polyglactin 910 was found to be well tolerated in this traumatized area of paranasal sinus bone and soft tissue and was totally absorbed in 4 months. Dacron-reinforced silicone sheeting induced a long-standing acute inflammatory reaction in a similar milieu. Partial osseus replacement of the orbital fenestrations occurred in all animals, but it was accompanied by distortion and erosion in apposition to the silicone sheeting. The study does not answer the question of whether orbital contour will be maintained on a long-term basis adjacent to a pneumatized sinus following reconstruction with a bioabsorbable implant.

Animals↗
PubMed2006

Clinical experience with a customized fenestrated endograft for juxtarenal abdominal aortic aneurysm repair.

Despite the numerous stent-graft devices available, unsuitable anatomy is still the greatest exclusion criterion for endovascular abdominal aortic aneurysm (AAA) repair (EVAR). The present report describes an on-site preprocedural customization of a conventional Zenith stent-graft device just before the endovascular procedure that includes the creation of fenestrations and scallops as necessary for the patient's anatomy. Three patients with difficult anatomy in whom conventional AAA repair posed a high degree of risk were treated with customization of the stent-graft device to fit disparate renal arteries. A single fenestration for the left renal artery was made in two cases, and a single scallop was made in the other case to accommodate the superior mesenteric artery. Gold beads were used to mark the location of the fenestration and scallop. The three cases were successfully performed without perceptible endoleaks in the follow-up period, which ranged from 4 to 14 months. No procedure-related complications were detected; however, pneumonia developed in one patient 3 weeks after EVAR. The initial results with this technique are encouraging, and the role of EVAR can be significantly increased with the use of this customization technique when the interventionalist does not have access to the commercially available devices or when the waiting time is too prolonged to accommodate the patient's clinical situation.

Aged↗
PubMed1992

Endothelial fenestration of the alveolar capillaries in interstitial fibrotic lung diseases.

A light and electron microscopy study was performed on endothelial cells of alveolar capillaries in biopsied lung tissues obtained from 28 patients with interstitial fibrotic lung diseases, including idiopathic pulmonary fibrosis, sarcoidosis, hypersensitivity pneumonitis, chronic eosinophilic pneumonia, collagen vascular diseases and acute interstitial pneumonia. In the relatively early stages of acute interstitial pneumonia, hypersensitivity pneumonitis and other diseases, the cytoplasms of the endothelial cells appeared swollen and electron-lucent and occasionally showed degeneration and necrosis. Although mitosis was not evident in the endothelium at any disease stage, some capillary endothelial cells showed regeneration. Furthermore, although rarely, they showed obvious phenotypic transformation into diaphragmed fenestrae in some limited segments of fibrotic lungs in the 20 of the 28 patients examined. The frequency of endothelial fenestration seemed to be correlated with the degree of interstitial fibrosis along the alveolar walls. In such fibrotic lung tissues, cuboidal metaplastic cells of bronchiolar origin proliferated on the luminal side. The mechanism of endothelial fenestration in the alveolar capillaries is assumed to be comparable with cuboidal metaplasia of alveolar epithelial cells. The alveolar capillary endothelium is recruited from the bronchiolar capillaries via bronchopulmonary anastomoses unless endothelial repair occurs in situ. Regenerating endothelial cells move into the alveolar capillary tubes along the remnant sleeves of the basement membrane. New endothelial processes finally display their original fenestrated structure while secreting irregular fragments of basement membrane during implantation in the capillary beds.

Adult↗
PubMed1991

Power drills to fenestrate exposed bone to stimulate wound healing.

Power drills can be used to stimulate the formation of granulation tissue over exposed cortical bone. These tools allow for the rapid fenestration and selective abrasion of large areas of exposed bone; fenestration and abrasion create the multiple bleeding points essential for the production of granulation tissue. The granulation tissue thus produced is allowed to grow out through the holes to cover bone. This procedure can be performed in an outpatient setting, usually without the need for either local or general anesthesia; it is particularly useful for patients considered to be poor risks for general anesthesia. Healing by granulation tissue is a somewhat slow process, but it has a high success rate, causes few complications, and produces very good cosmetic results. Two cases illustrate the method of fenestration of exposed cranial bone to stimulate granulation tissue. Specific instructions describe the needed care of exposed bone.

Aged↗
PubMed2002

Transhepatic closure of a post-fontan hepatic veins to left atrium fenestration in visceral heterotaxia and dextrocardia.

This article reports on the transhepatic closure of post-Fontan hepatic veins to left atrium fenestration in a 13-year-old girl with left atrial isomerism, dextrocardia, azygos continuation to the left superior vena cava, and median liver. The transhepatic route seemed to be the less tortuous access to the fenestration which was previously partially occluded with a CardioSeal device. The hepatic veins were entered at the left abdominal side using fluoroscopic guidance and the fenestration was uneventfully occluded with an Amplatzer septal occluder device.

Adolescent↗
PubMed2005

"Taking in the waist": adjusting the size of a stented fontan fenestration.

Early spontaneous closure of a fenestration following Fontan palliation may complicate the postoperative management of such patients. The creation of a fenestration in the catheterization laboratory with an intravascular stent may improve these patients' hemodynamic status. The aim of this study is to present a new technique to reduce the diameter of stented Fontan fenestrations in those patients in whom the stent diameter is functionally made too large.

Adult↗
PubMed1996

Treatment of labial fenestration of maxillary central incisor.

A case of external inflammatory root resorption and labial fenestration in a maxillary central incisor is presented. The root canal was dressed with pure calcium hydroxide mixed with normal saline for 1 month before it was obturated with gutta percha and apicoectomy surgery undertaken to attempt primary closure of the fenestration. The PDL and the fenestration healed uneventfully.

Alveolar Bone Loss↗
PubMed1990

Relief of mesenteric ischemia in type III aortic dissection with percutaneous fenestration of the aortic septum.

Subacute mesenteric ischemia developed 2 months after initial presentation in a patient with a type III aortic dissection. Percutaneous transfemoral fenestration of the septum between the true and false lumens resulted in resolution of clinical, angiographic, and manometric signs of ischemia. Continued expansion of the false lumen required aortic resection and graft replacement of the distal thoracic and abdominal aorta 2 months after the fenestration procedure. At operation, the fenestration site appeared as a 2-cm horizontal tear in the aortic septum, free of adherent thrombus and unrelated to expansion of the false lumen.

Aortic Dissection↗
PubMed2005

VEGF-dependent plasticity of fenestrated capillaries in the normal adult microvasculature.

Unlike during development, blood vessels in the adult are generally thought not to require VEGF for normal function. However, VEGF is a survival factor for many tumor vessels, and there are clues that some normal blood vessels may also depend on VEGF. In this study, we sought to identify which, if any, vascular beds in adult mice depend on VEGF for survival. Mice were treated with a small-molecule VEGF receptor (VEGFR) tyrosine kinase inhibitor or soluble VEGFRs for 1-3 wk. Blood vessels were assessed using immunohistochemistry or scanning or transmission electron microscopy. In a study of 17 normal organs after VEGF inhibition, we found significant capillary regression in pancreatic islets, thyroid, adrenal cortex, pituitary, choroid plexus, small-intestinal villi, and epididymal adipose tissue. The amount of regression was dose dependent and varied from organ to organ, with a maximum of 68% in thyroid, but was less in normal organs than in tumors in RIP-Tag2-transgenic mice or in Lewis lung carcinoma. VEGF-dependent capillaries were fenestrated, expressed high levels of both VEGFR-2 and VEGFR-3, and had normal pericyte coverage. Surviving capillaries in affected organs had fewer fenestrations and less VEGFR expression. All mice appeared healthy, but distinct physiological changes, including more efficient blood glucose handling, accompanied some regimens of VEGF inhibition. Strikingly, most capillaries in the thyroid grew back within 2 wk after cessation of treatment for 1 wk. Our findings of VEGF dependency of normal fenestrated capillaries and rapid regrowth after regression demonstrate the plasticity of the adult microvasculature.

Aging↗
PubMed1997

A fiber matrix model for the filtration through fenestral pores in a compressible arterial intima.

We advance a new hypothesis to explain the changes in hydraulic conductivity of an intact artery wall with transmural pressure previously observed by Tedgui and Lever [Am. J. Physiol. 247 (Heart Circ. Physiol. 16): H784-H791, 1984] and Baldwin and Wilson [Am. J. Physiol. 264 (Heart Circ. Physiol. 33): H26-H32, 1993]. This hypothesis suggests that compaction due to pressure loading of the proteoglycan matrix in the arterial intima near fenestral pores of the internal elastic lamina (IEL) leads to a narrowing of the pore entrance area and a large decrease in local intrinsic Darcy permeability of the matrix. To quantitatively assess the feasibility of this mechanism, a local two-dimensional model is proposed to study filtration flow in the vicinity of fenestral pores in a compressible intima. Using a heterogenous fiber matrix theory, we first predict the change in Darcy permeability with intimal thickness (Li). The model then calculates local velocity profiles and pressure distributions in the intima and media. The results show a marked nonlinear steepening of intimal pressure profiles near fenestral pores when the intima thins at higher luminal pressures. The predicted relative change in resistances of the IEL (with intima, R(I)) and of the media (Rm) shows a steep increase in R(I)/Rm when Li is <20% of its unstressed value. Numerical results also suggest that intimal compression has a limiting behavior in which the much stiffer collagen fibrils inhibit further compaction at high pressures after the proteoglycan matrix is maximally compressed. Predictions are also presented to show how different transmural pressures alter growth of an intimal horseradish peroxidase spot that derives from a localized (a single cell's boundary) endothelial leakage. Such a prediction is amenable to experimental verification.

Animals↗
PubMed1985

Fenestrated capillaries in human parietal and rabbit diaphragmatic peritoneum.

Samples of parietal peritoneum from 20 patients (11 of them chronic uremics) and biopsies of diaphragmatic peritoneum from 5 apparently normal female New Zealand rabbits were examined by electron microscopy. One out of 20 patients and 3 out of 5 rabbits showed fenestrated capillaries. This report is the first published demonstration of the existence of fenestrated capillaries in human parietal and rabbit diaphragmatic peritoneum. They represented a small fraction of the peritoneal microvascular bed which was mainly formed by capillaries of the continuous type. Fenestrae of the observed fenestrated capillaries showed diaphragms. Results of this study indicate that different peritoneal microvascular segments can show different microvascular ultrastructures and possibly have a different physiology and different mechanisms of transperitoneal transfer of water and solutes.

Animals↗
PubMed1990

Baffle fenestration with subsequent transcatheter closure. Modification of the Fontan operation for patients at increased risk.

Ventricular dysfunction, elevated pulmonary vascular resistance, and residual distal pulmonary artery distortion contribute to early mortality after a Fontan operation; they may be transient or reversible. A baffle fenestration, allowing right-to-left shunting, maintains cardiac output and limits right atrial pressure. A baffle fenestration was surgically created at the time of a modified Fontan repair in 20 consecutive patients. Risk factors included pulmonary artery pressure of 18 mm Hg or more, end-diastolic pressure of 12 mm Hg or more, valvar regurgitation, pulmonary artery distortion, pulmonary vascular resistance of 2 Woods' units or more, ventricular outflow obstruction, and complex anatomy. Nineteen of 20 patients survived. After the operation, mean arterial oxygen saturation was 86%, mean right atrial pressure was 15 mm Hg, and mean duration of pleural effusions was 6 days. Twelve of 19 survivors tolerated early test occlusion and had permanent transcatheter umbrella closure. Four patients failed early test occlusion, with a significant decrease in venous O2 saturation and a rise in central venous pressure, due to ventricular dysfunction, pulmonary artery distortion, or aortopulmonary collaterals. Three of four had successful late closure of the fenestration after correction of these abnormalities.

Cardiac Catheterization↗
PubMed2005

Total cavopulmonary connection flow with functional left pulmonary artery stenosis: angioplasty and fenestration in vitro.

BACKGROUND: In our multicenter study of the total cavopulmonary connection (TCPC), a cohort of patients with long-segment left pulmonary artery (LPA) stenosis was observed (35%). The clinically recognized detrimental effects of LPA stenosis motivated a computational fluid dynamic simulation study within 3-dimensional patient-specific and idealized TCPC pathways. The goal of this study was to quantify and evaluate the hemodynamic impact of LPA stenosis and to judge interventional strategies aimed at treating it. METHODS AND RESULTS: Simulations were conducted at equal vascular lung resistance, modeling both discrete stenosis (DS) and diffuse long-segment hypoplasia with varying degrees of obstruction (0% to 80%). Models having fenestrations of 2 to 6 mm and atrium pressures of 4 to 14 mm Hg were explored. A patient-specific, extracardiac TCPC with 85% DS was studied in its original configuration and after virtual surgery that dilated the LPA to 0% stenosis in the computer medium. Performance indices improved exponentially (R2>0.99) with decreasing obstruction. Diffuse long-segment hypoplasia was approximately 50% more severe with regard to lung perfusion and cardiac energy loss than DS. Virtual angioplasty performed on the 3-dimensional Fontan anatomy exhibiting an 85% DS stenosis produced a 61% increase in left lung perfusion and a 50% decrease in cardiac energy dissipation. After 4-mm fenestration, TCPC baffle pressure dropped by approximately 10% and left lung perfusion decreased by approximately 8% compared with the 80% DS case. CONCLUSIONS: DS <60% and diffuse long-segment hypoplasia <40% could be considered tolerable because both resulted in only a 12% decrease in left lung perfusion. In contrast to angioplasty, a fenestration (right-to-left shunt) reduced TCPC pressure at the cost of decreased left and right lung perfusion. These results suggest that pre-Fontan computational fluid dynamic simulation may be valuable for determining both the hemodynamic significance of LPA stenosis and the potential benefits of intervention.

Angioplasty↗
PubMed2000

Repair of mycotic paravisceral aneurysm with a fenestrated stent-graft.

PURPOSE: To report the successful endovascular repair of a mycotic paravisceral aneurysm using a fenestrated stent-graft. METHODS AND RESULTS: A 55-year-old white female with a history of rheumatoid arthritis presented with an 8-cm paravisceral aneurysm secondary to pneumonia complicated by empyema. Intravascular ultrasound identified a defect in the aortic wall at the level of the celiac axis. Repair was accomplished with a fenestrated stent-graft that excluded the aneurysm and maintained flow to the celiac axis and superior mesenteric artery. Recovery was uneventful and the patient was discharged in 2 days. Six-month follow-up computed tomographic scanning confirmed aneurysm exclusion and flow to the celiac and superior mesenteric arteries. There was no evidence of graft infection. The patient died from a clinically diagnosed myocardial infarction 10 months after the stent-graft repair. CONCLUSIONS: Fenestrated stent-graft repair may evolve into a useful technique for the treatment of mycotic paravisceral aneurysms.

Aneurysm, False↗