Foam Delivery Research Articles

A mechanism for improved talc pleurodesis via foam delivery

Talcum powder is recognized as the leading drug for pleurodesis, a treatment of choice for malignant pleural effusions. Recently, it was shown that hydrogel foam delivery systems significantly enhanced the number of adhesions between the chest wall and the lung in a New Zealand rabbit model due to the sol-gel transition. However, many questions still remain regarding the cause of improved efficacy, such as: (1) Would only hydrogel foams improve the efficacy of talc pleurodesis? (2) Is it possible to achieve the same efficacy of hydrogels using non-hydrogel foams? 3) What are the physicochemical properties that can be correlated to the efficacy of talc pleurodesis? In this study, we use non-hydrogel foam formulations to determine the efficacy of pleurodesis. Foam stability and rheology of the formulations were correlated to adhesion formation. The results clearly suggest a correlation of pleurodesis efficacy to the viscosity and modulus of the foam delivery system.

Prototype continuous microwave foam-mat dryer: design and fabrication.

A prototype microwave foam mat dryer with continuous operation was fabricated for tomato and guava. Results of preliminary studies on microwave foam mat drying of tomato and guava were used to design the prototype. The continuous foaming operation was achieved with the help of a submersible pump controlled by a time switch which ensured the delivery of pulp into foaming container and streamlined the delivery of foam on the drying surface (belt). The drying section presented a combination of hot air and microwaves, which resulted in accelerated heating and subsequently drying of the foam. Dried flakes were collected at the exit with the scrapper blade, which ensured appreciable recovery. The quality evaluation of guava pulp and tomato pulp dried at different microwave powers and inlet air temperatures revealed that the products dried at 1000W microwave power and 50°C exhibited excellent physicochemical properties in both the cases. Performance evaluation study depicted that the capacity of the dryer for guava drying was 4.84l/h, the final moisture retention in the dried powder was 0.059g H2O/g d.m, recovery was 98.34% and energy consumption was 1.32kWh/l. Similarly, for tomato drying the capacity, final moisture content, recovery and energy consumption were 4.03l/h, 0.062g H2O/g d.m, 91.29% and 1.49kWh/l respectively.

The efficacy of hydrogel foams in talc Pleurodesis

BackgroundMalignant pleural effusions are a serious complication of many late stage cancers that adversely affect quality of life. Pleurodesis with talc slurry is a standard treatment option, but clinical failures occur, possible due to poor talc delivery. A novel drug-delivery system was developed that fills the entire thoracic cavity with a liquid foam containing talc. The foam is designed to gel and adhere to the tissue walls at body temperature, to improve talc deposition and efficacy.MethodsRheology, foam stability, and ex-vivo coating and bio-adhesion studies were performed on three concentrations of a novel hydrogel talc foam system that was developed to improve delivery of talc to the pleural surfaces. A New Zealand rabbit model of pleurodesis was used to evaluate effectiveness of the foams at inducing adhesion formation and compared to talc slurry. The rabbits were recovered after they had one of the test agents instilled into their pleura, and then sacrificed after 28 days. Pleurodesis was assessed by a blinded pathologist using a standardized pathological scoring system.ResultsAll talc foam formulations produced foams that gelled at physiological temperatures and were relatively stable for at least two hours. As the concentration of the formulation increased the gelation temperature decreased and the foam adhesiveness increased. Rabbits that received talc foam had significantly greater adhesion formation than talc slurry (mean score of 2.21 vs. 1.18 (p < 0.05)). Rabbits that received the 20% foam developed the most adhesions.ConclusionsThis study demonstrates that our triblock copolymer hydrogel foam delivery system enhances adhesion formation in an experimental model. This novel approach can have important clinical impact, potentially improving efficacy of existing therapies and reducing the need for more invasive treatments.

Application of reinforcement learning to fire suppression system of an autonomous ship in irregular waves

In fire suppression, continuous delivery of water or foam to the fire source is essential. The present study concerns fire suppression in a ship under sea condition, by introducing reinforcement learning technique to aiming of fire extinguishing nozzle, which works in a ship compartment with six degrees of freedom movement by irregular waves. The physical modeling of the water jet and compartment motion was provided using Unity 3D engine. In the reinforcement learning, the change of the nozzle angle during the scenario was set as the action, while the reward is proportional to the ratio of the water particle delivered to the fire source area. The optimal control of nozzle aiming for continuous delivery of water jet could be derived. Various algorithms of reinforcement learning were tested to select the optimal one, the proximal policy optimization.

An improved method of delivering a sclerosing agent for the treatment of malignant pleural effusion.

BackgroundMalignant pleural effusion (MPE) is a devastating sequela associated with cancer. Talc pleurodesis is a common treatment strategy for MPE but has been estimated to be unsuccessful in up to 20–50% of patients. Clinical failure of talc pleurodesis is thought to be due to poor dispersion. This monograph reports the development of a foam delivery system designed to more effectively coat the pleural cavity.MethodsC57BL/6 mice were injected with Lewis lung carcinoma (LL/2) cells intrapleurally to induce MPE. The mice then received either normal saline (NS) control, foam control (F), talc slurry (TS, 2 mg/g) or talc foam (TF, 2 mg/g). Airspace volume was evaluated by CT, lungs/pleura were collected, and percent fibrosis was determined.ResultsThe TF group had significantly better survival than the TS group (21 vs 13.5 days, p < 0.0001). The average effusion volume was less in the talc groups compared to the control group (140 vs 628 μL, p < 0.001). TF induced significant lung fibrosis (p < 0.01), similar to TS. On CT, TF significantly (p < 0.05) reduced loss of right lung volume (by 30–40%) compared to the control group. This was not seen with TS (p > 0.05).ConclusionsThis report describes using a novel talc foam delivery system for the treatment of MPE. In the LL/2 model, mice treated with the TF had better survival outcomes and less reduction of lung volume than mice treated with the standard of care TS. These data provide support for translational efforts to move talc foam from animal models into clinical trials.

A Novel Triblock Copolymer Hydrogel Foam Delivery System to Improve Talc Pleurodesis Efficacy

A Novel Triblock Copolymer Hydrogel Foam Delivery System to Improve Talc Pleurodesis Efficacy

Experimental study and implementation of a novel internal foam spraying system for roadheaders

Foam technology utilizes the good coverage of foam to form a closed space around dust sources. The foam then wets the dust particles, causing them to adhere before they spread into the air, resulting in better dust control than with water sprays. In the process of foam dust control at a heading face, the foam spray trajectory is highly influenced by the wind, making it difficult to focus foam on the dust sources, which wastes the foam and reduces dust control efficiency. To resolve this problem, the idea of transporting foam to the cutting head through the roadheader’s inner pipeline is proposed. To adapt to the high resistance of foam delivery in the roadheader’s inner pipeline, according to the water and air supply of the heading face, a table water-jet suction device and porous spiral coupling foaming device were designed, and the working conditions were tested using a self-designed experiment system in the laboratory. The results showed that the foaming agent could be automatically added into the device at a working water flow rate of 1–1.6m3/h at a ratio of 1%. The optimum air flow was 45–50m3/h, in which range the foam expansion ratio reached the maximum and the outlet pressure demand was satisfied. Field application showed that the new foam method had a better dust control efficiencies than traditional foam methods.

Progression of wet granulation in a twin screw extruder comparing two binder delivery methods

The two available wetting methods for twin screw granulation, namely foam delivery and liquid injection, were studied in detail by examining granule development along the screws as powder formulation and screw design were varied. Granulation profiles were determined by particle size analysis of samples along the screws collected using the “screw pullout” technique. Analysis of the particle size and porosity of produced granules revealed only minor differences between the two methods of wetting despite the larger dropsize of liquid injection compared to foam delivery. Excipients like microcrystalline cellulose or hydroxypropyl methyl cellulose with poor spreading properties, quantified by their specific penetration time and nucleation ratio, made the differences more apparent. The general similarities in granulation independent of wetting method implied that binder dispersion in an extruder was dominated by mechanical dispersion. Screw design (i.e., location of kneading block) had the dominant effect on the granulation process in this study. © 2014 American Institute of Chemical Engineers AIChE J, 61: 780–791, 2015

Comment to: Catheter-directed foam sclerotherapy for insufficiency of the great saphenous vein: occlusion rates and patient satisfaction after one year, by Williamsson C, Danielsson P, Smith L. Phlebology 2012:1-6.

Between November 2007 and October 2008, 100 consecutive symptomatic patients with verified axial reflux in the GSV were treated with a catheter-directed foam sclerosation technique (CDS). CDS delivers the foam during a short period of time directly to the intended site, along the length of the GSV, with less impact from surrounding factors. The catheter induces a vasospasm which might further enhance drug interaction with the vein wall. Median age was 52.5 years (range 18&ndash;92), 28 men and 72 women. All patients had visible varicose veins. Twenty-three had recurrent varicose veins. The treatment was performed in the outpatient clinic by a team consisting of two vascular surgeons and two nurses. Exclusion criteria were allergy to polidocanol, a very tortuous vein (which could make the catheters impossible to advance) or a GSV diameter exceeding 10 mm at the terminal valve. The skin was infiltrated with local anesthesia. The vein was accessed by a micro-puncture introducer set and a 0.35 Fr guide wire was advanced proximally under US surveillance and positioned at the SFJ. A catheter was introduced over the guide wire and positioned approximately 2 cm distal to the SFJ and the guide wire was removed. The table was slightly tilted to elevate the leg to empty the GSV. Ten mL sclerosing foam (SF) was made by mixing 2 mL chilled 3% polidocanol and 8 mL air. The SFJ and site of puncture was compressed for five minutes and the thigh massaged to fill superficial varicosites with foam. No additional local injection of foam was given. All patients wore two-layer short stretch compression bandages for one to five days after treatment. Evaluation with US was performed at two weeks and at one year after treatment. Foam delivery along the GSV was technically successful in 94 of the 100 patients. The median time for the procedure was 22 (8&ndash;90) min. The complete treatment exceeded 30 min in 20 patients, but only in two patients following the 50th patient. At the US control two weeks after treatment, the GSV was completely occluded in 92 of the 94 successfully treated patients. At the one-year follow-up, 84% (79/94) were satisfied with the result. The one-year US showed that 70% (64/91) of the GSVs were completely occluded, 15% (14/91) of the GSVs were recanalized and 14% (13/91) were partly occluded. No major complications occurred such as visual disturbance, pulmonary embolism, DVT or infection. Two patients had superficial thrombophlebitis; at the one-year follow-up 26 patients had pigmentations to some extent. The cost for the drugs and the single-use medical material was calculated to be 106 EUR.

Foam-Assisted Delivery of Nanoscale Zero Valent Iron in Porous Media

AbstractFoam is potentially a promising vehicle to deliver nanoparticles for vadose-zone remediation because foam can overcome the intrinsic problems associated with solution-based delivery, such as preferential flow and contaminant mobilization and spreading. In this work, the feasibility of using foam to deliver nanoscale zero valent iron (nZVI) in unsaturated porous media was investigated. Foam generated using the surfactant sodium lauryl ether sulfate (SLES) showed excellent ability to carry nZVI. SLES and nZVI concentrations in the foaming solutions did not affect the percentages of nZVI concentrations in foam relative to nZVI concentrations in the solutions. When foams carrying nZVI were injected through the unsaturated columns, the fractions of nZVI exiting the column were much higher than those when nZVI was injected with liquid. The enhanced nZVI transport implies that foam delivery could significantly increase the radius of influence of injected nZVI. The type and concentrations of surfactants a...

Modeling foam delivery mechanisms in deep vadose-zone remediation using method of characteristics

This study investigates foam delivery mechanisms in vadose-zone remediation by using Method of Characteristics (MoC), a mathematical tool long been used for the analysis of miscible and immiscible flooding in porous media in petroleum industry. MoC converts the governing material-balance partial differential equations into a series of ordinary differential equations, and the resulting solutions are in a form of wave propagation (more specifically, for chemical species and phase saturations) through the system as a function of time and space.Deep vadose-zone remediation has special features compared to other conventional remediation applications. They include, not limited to, a high level of heterogeneity, a very dry initial condition with low water saturation (Sw), pollutants such as metals and radionuclides fully dissolved in groundwater, and a serious concern about downward migration during the remediation treatments. For the vadose-zone remediation processes to be successful, the injected aqueous phase should carry chemicals to react with pollutants and precipitate them for immobilization and stabilization purposes. As a result, foams are believed to be an effective means, and understanding foam flow mechanism in situ is a key to the optimal design of field applications.Results show that foam delivery mechanism is indeed very complicated, making the optimum injection condition field-specific. The five major parameters selected (i.e., initial saturation of the medium, injection foam quality, surfactant adsorption, foam strength, and foam stability) are shown to be all important, interacting with each other. Results also imply that although dry foam injection is generally recommended, too dry injection condition is found to hurt this process due to slow foam propagation.

Growth inhibition and stimulation of Shewanella oneidensis MR-1 by surfactants and calcium polysulfide

Foam delivery technology (FDT) uses surfactant based foam to immobilize subsurface contaminants in situ. Where traditional approaches are impractical, FDT has the potential to overcome many of the technical challenges facing the remediation of contaminated deep vadose zone environments. However, little is known about the effects these reactive chemicals may have on microorganisms inhabiting the contaminated subsurface. In addition, there are currently no standard assays to assess microbial responses to subsurface remedial treatments while these agents are under development. The objective of this study was to develop a rapid laboratory assay to assess the potential growth inhibition and/or stimulation of microorganisms following exposure to candidate FDT components. Calcium polysulfide (CPS) and several surfactants (i.e. sodium laureth sulfate (SLES), sodium dodecyl sulfate (SDS), cocamidopropyl betaine (CAPB) and NINOL40-CO) have diverse chemistries and are candidate components of FDT. Shewanella oneidensis MR-1 cultures were exposed to a range of concentrations of these chemicals to determine the minimum bactericidal concentration (MBC) and the growth and viability potential of these components. Concentrations of SDS higher than 700μM were toxic to S. oneidensis MR-1 growth over the course of four days of exposure. The relative acute toxicity order for these compounds was SDS⪢CPS⪢NINOL 40-CO>SLES≥CAPB. Dose dependent growth decreases (20–100mM) were observed in the CAPB and SLES treated cultures and both CPS and NINOL 40-CO were toxic at all concentrations tested (1.45–7.25mM CPS). Both SLES (20–100mM) and SDS at lower concentrations (20–500μM) were stimulatory to S. oneidensis MR-1 indicating a capacity to be used as a carbon source. These studies also identified potentially key component characteristics, such as precipitate formation and oxygen availability, which may prove valuable in assessing the response of subsurface microorganisms. This benchtop system provides a capability to assess adverse microbial-remediation responses and contributes to the development of in situ remedial chemistries before they are deployed in the field.

Pilot Study Evaluation of Standard Laparoscopic Suturing and a Novel Parenchymal Apposition Mechanism for Minimally Invasive Renal Reconstruction

The most technically demanding portion of a laparoscopic partial nephrectomy is the renorrhaphy. The purpose of this study was to determine whether a parenchymal apposition mechanism (PAM) device would be as effective as standard laparoscopic technique (SLT) with respect to efficiency, capability, and safety of renal defect closure. In this pilot study, participants were recruited to perform surgical reconstruction of a standardized renal parenchymal defect with both SLT and the PAM. The PAM prototype was engineered using two salmon egg hooks connected by absorbable suture and placed within a V-shaped foam delivery mechanism. After hook placement, tensioning of the connecting suture using a Weck clip apposed the defect edges. Each participant performed a single closure with SLT and with the PAM device of a standardized defect in ex vivo porcine kidneys. Closure time, tissue trauma/damage during closure, and the intraparenchymal pressure were recorded. A total of 13 subjects, 7 medical students, 3 residents, 2 fellows, and 1 attending were enrolled. There was no statistical difference between the two methods of closure in average time for closure. In a subgroup analysis of subjects who had performed laparoscopic reconstructive procedures as the primary surgeon, SLT was significantly faster than PAM (P=.036). Mean pressures achieved in attempted closure using SLT and PAM were not significantly different (0.38 N for both groups; P=.99). The mean parenchymal trauma rating was not significantly different between the groups; however, the upper limit of the range of trauma ratings was greater in the standard closures. This pilot study demonstrated the feasibility of PAM use in an ex vivo porcine kidney model. Additional testing and continued design modifications are necessary to explore its use in laparoscopic reconstruction of the kidney and other organs.

Enhanced remedial amendment delivery to subsurface using shear thinning fluid and aqueous foam

A major issue with in situ subsurface remediation is the ability to achieve an even spatial distribution of remedial amendments to the contamination zones in an aquifer or vadose zone. Amendment delivery to the aquifer using shear thinning fluid and to the vadose zone using aqueous foam has the potential to enhance the distribution. 2-D saturated flow cell experiments were conducted to evaluate the enhanced fluid sweeping over heterogeneous system, improved contaminant removal, and extended amendment presence in low-permeability zones achieved by shear thinning fluid delivery. Unsaturated column and flow cell experiments were conducted to investigate the improvement on contaminant mobilization mitigation, amendment distribution, and lateral delivery implemented by foam delivery. It was demonstrated that the shear thinning fluid injection enhanced the fluid sweeping and increased the delivery of remedial amendment into low-perm zones. The presence of amendment distributed by the shear thinning fluid in the low-permeability zones was increased. Foam delivery was shown to mitigate the mobilization of highly mobile contaminant from sediments. It also achieved more uniform amendment distribution in a heterogeneous unsaturated system, and demonstrated remarkable increasing in lateral distribution of the injected liquid compared to direct liquid injection.

Clinical Evaluation of 35% Urea in a Water-Lipid–Based Foam Containing Lactic Acid for Treatment of Mild-to-Moderate Xerosis of the Foot

We evaluated 35% urea in a water-lipid-based foam delivery system containing lactic acid in participants with mild-to-moderate xerosis of the foot. This 4-week open-label study enrolled 12 participants with xerosis of the foot; six participants were diabetic and six were nondiabetic. Study medication was applied to the affected area twice daily. All adverse events were recorded. Disease severity was measured at baseline and at the end of treatment by Investigator's Global Assessment, and investigator's and participant's signs and symptoms scores. At 4 weeks, compliance and participant satisfaction were determined from participant diaries and a 16-item survey instrument, respectively. Ten participants completed the study. No adverse reactions were noted with application of the foam. All of the participants who completed the study experienced an improvement in xerosis. The median Investigator's Global Assessment score decreased significantly from baseline to the end of treatment (P = .005). The investigator and participants observed significant improvement (P < .05) in redness, scaling, and cracking from baseline to the end of treatment. Compliance with the regimen was good, and participants expressed satisfaction with the product. Thirty-five percent urea in a water-lipid-based foam delivery system containing lactic acid can be an appropriate treatment option for mild-to-moderate xerosis of the foot.

Foam, a promising vehicle to deliver nanoparticles for vadose zone remediation

Foam delivery of remedial amendments for in situ immobilization of deep vadose zone contaminants can overcome the intrinsic problems associated with solution-based delivery, such as preferential flow and contaminant mobilization. In this work, the feasibility of using foam to deliver nanoparticles in unsaturated porous media was investigated. Carboxyl-modified polystyrene latex microspheres were used as surrogates for nanoparticles of remediation purposes. Foams generated from the solutions of six commonly available surfactants all had excellent abilities to carry the microspheres. The presence of the microspheres did not reduce the stabilities of the foams. When microsphere-laden foam was injected through the unsaturated columns, the fractions of microspheres exiting the column were much higher than that when the microsphere water suspensions were injected through the columns. The enhanced microsphere transport implies that foam delivery could significantly increase the radius of influence of injected nanoparticles of remediation purposes. Reduced tension at air–water interfaces by the surfactant and increased driving forces imparted on the microspheres at the interfaces by the flowing foam bubbles may have both contributed to the enhanced transport. Preliminary tests also demonstrated that foam can carry significant fractions of zero valent iron nanoparticles at concentrations relevant to field remediation conditions (up to 5.3gL−1). As such, this study demonstrates that surfactant foam is potentially a promising vehicle to deliver nanoparticles for vadose zone remediation.

Key Observations of Liquefied Natural Gas Vapor Dispersion Field Test with Expansion Foam Application

Expansion foam has been recommended as one of the safety provisions for mitigating accidental liquefied natural gas (LNG) releases. However, the effectiveness of foam in achieving this objective has not been sufficiently reported in outdoor field tests. This paper investigates the effects of expansion foam application on LNG vapor dispersion in field experiments, which were performed at the Brayton Fire Training Field. Specifically, this study aimed to obtain key parameters such as temperature changes of methane and foam, and the extent reduction of vapor concentration for evaluating the use of foam to control the vapor hazard from spilled LNG. In addition, the underlying mechanisms of foam when it contacts with an LNG pool and foam breaking rates were also investigated. Results showed that expansion foam was effective in increasing the buoyancy of LNG vapor by raising the temperature of the vapor permeated through the foam layer, and ultimately decreasing the methane concentrations in the downwind direction. On the basis of these findings, several recommendations were made for improving foam delivery methods and foam properties which can be used for controlling LNG vapor dispersion.

Foam Delivery of Amendments for Vadose Zone Remediation: Propagation Performance in Unsaturated Sediments

Foam delivery of remedial amendments is potentially useful for vadose zone remediation because aqueous amendments are delivered while a low water content is maintained in the treated zones. The transport behavior of foam in the vadose zone has not been well studied. Benchtop‐scale column tests were conducted to investigate foam transport, foaming gas and liquid propagation, pressure buildup and distribution, the influence of foam quality and sediment permeability on foam injection pressure, and liquid uptake and distribution during foam flow in unsaturated sediments. Results indicated that under unsaturated conditions, the foaming gas front traveled much faster than the foam front where bubble rupture was significant. A liquid front was formed ahead of the foam flow front. The accumulated liquid in this front was mainly composed of the water injected with the foam. The foam injection pressure was primarily attributed to the resistance to foam flow by the sediment but not to the movement of the water ahead of the foam front. The foam had a high effective viscosity compared with water. A near‐linear pressure distribution within the foam‐occupied column section was observed. At a fixed injection rate, higher foam quality resulted in lower injection pressure. Higher permeability sediments did not necessarily have a lower foam injection pressure because other factors, such as the foam injection rate, foam bubble diameter, and sediment pore size, also influenced the pressure. In the foam flushed region, the liquid uptake and water content distribution in the sediment was negligibly affected by the initial water content and the foam injection rate within the ranges tested in this study. The implications of these findings to field remediation application were considered.

Foam granulation: Binder dispersion and nucleation in mixer-granulators

Traditional wet granulation method involves spraying of liquid binder onto a moving powder bed to granulate the powder particles in the granulator. A new alternative method of wet granulation has been developed where foam delivery of binder is used to granulate the powder particles. This study investigated binder distribution in wet granulation and focused on the nucleation stage, where nuclei are formed during the initial binder distribution. Nucleation experiments were used to study the formation of nuclei by the foam and spray delivery methods in a high shear mixer-granulator. The distribution of foams on a dynamic powder bed were also investigated by filming small portion of foams as they penetrated into moving powder beds under different powder flow conditions in a high shear mixer-granulator. Nucleation experiments in this study show that foam delivery tends to create a narrower nuclei size distribution during the early stage of wet granulation process compared to spray delivery at the same processing conditions, demonstrating the potential of foam granulation in achieving improved binder distribution. For foam delivery, the nuclei formation is influenced by the foam properties and powder flow conditions in the granulator. The experiments show that the narrowest nuclei size distribution is obtained by granulating with high-quality foam and intensive powder mixing conditions. Coarser nuclei are formed when low-quality foam is dispersed in a less intensively agitated powder. The interactions of foam quality and the powder flow pattern are discussed and two distinct wetting and nucleation mechanisms are proposed: (1) under bumping flow, a low-quality foam tends to induce localised wetting and nucleation. The wetting and nucleation is “foam drainage” controlled. (2) Under roping flow, foam will be dispersed by the motion of the agitated powder. The wetting and nucleation is “mechanical dispersion” controlled.

Catheter-directed foam sclerotherapy of incompetent saphenous reflux: early results

To describe observation of availability of catheter-directed foam sclerotherapy for the great saphenous vein varicosis. A selective series of 30 patients of vein varicosis were treated with foam sclerotherapy using a standard technique for foam delivery from April 2008 to August 2008. Patients were treated with 1% polidocanol foam through a catheter, which was inserted percutaneously over a guidewire in the great saphenous vein (GSV). All successfully treated patients were examined by colour duplex two weeks after the procedure. Thirty patients with an insufficiency reflux of the GSV were treated with the catheter-directed foam sclerotherapy. Primary technical success was achieved in all the patients. The concentrations (1.0%) and doses (6 to 8 ml) of polidocanol was mainly we used. Five patients experienced transient scotomas and developed segmental phlebitis of a collateral vein. The intervention was well tolerated in all patients without the occurrence of serious side effects. In 27 of the 30 treated patients (90%), a closure of the GSV was found at control visits 2 weeks, 3 months after treatment. The use of an endovascular catheter inserted percutaneously over a guidewire is feasible in most patients and has resulted in high primary occlusion rates.