Endovenous laser coagulation: asymmetrical heat transfer (modeling in water)

Минаев, В. П.; Минаев, Н. В.; Богачев, В. Ю.; Kaperiz, K. A.; Yusupov, V. I.

doi:10.1007/s10103-020-03184-y

Cited by 8 publications

(6 citation statements)

References 17 publications

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“…Использование водопоглощаемых излучений позволило осуществить моделирование происходящих при ЭВЛК процессов в реальном времени с использованием оптических методов регистрации [27,28]. В этих экспериментах использовались излучения с длинами волн λ = 1,55 и 1,94 мкм, а также замороженная плазма донорской крови после ее размораживания.…”

Section: развитие метода эндовенозной лазерной коагуляцииunclassified

“…Прозрачность и минимальное рассеяние в плазме позволили использовать оптическую регистрацию. В ходе экспериментов исследовали теплоперенос при фиксированном положении световодов в плазме, налитой в кювету [27]. В другой работе исследовались процессы, происходящие в процессе моделирования ЭВЛК, при этом вена моделировалась стеклянной трубкой с внутренним диаметром 3,75 мм [28].…”

Section: развитие метода эндовенозной лазерной коагуляцииunclassified

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Endovenous laser coagulation of varicose veins: evolution continues

Минаев¹,

Богачев

Kaperiz

2023

Ambulatornaya khirurgiya

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The article discusses the evolution of the endovenous laser ablation technique for the treatment of varicose vein disease of lower extremities. The history of studies aimed at improving the endovenous laser ablation is provided. The authors described the features of endovenous laser ablation with wavelengths from λ = 0.445 to 1.94 μm, alongside with edge- and radial-emitting working fibers, as well as fibers with radiation absorption at its distal end. The physical and biophysical mechanisms of the most popular to-date method for outpatient treatment of varicose vein disease of lower extremities are reviewed. The propagation process of laser radiation in the scattering medium is described, and the important role of the radiation scattering effect on the depth of its penetration into biological tissues is shown. The processes that take place during endovenous laser ablation are considered. The difference in physical processes that take place during the use of laser radiation mainly absorbed by hemoglobin (hemoglobin-absorbed range) and by water (water-absorbed range) is described. Expedience of simulating the processes that take place during endovenous laser ablation with the use of blood plasma has been substantiated. The blood plasma simulation demonstrated the decisive action of laser-induced boiling on thermal damage to the vein wall, which causes its fibrous transformation. It has been shown that the use of radial-emitting fibres during intense boiling generates steam bubbles around the site of radiation coupling. The contents of such steam bubbles do not absorb radiation, which thus reaches the venous wall, causing its symmetrical thermal damage. The advantages of using water-absorbing radiation with a wavelength of λ = 1.94 μm in conjunction with a radial-emitting fibre have been substantiated.

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Section: развитие метода эндовенозной лазерной коагуляцииunclassified

Endovenous laser coagulation of varicose veins: evolution continues

Минаев¹,

Богачев

Kaperiz

2023

Ambulatornaya khirurgiya

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“…There are many different forms of EVLA and RFA. In the most basic forms, EVLA fibres can be bared-tipped, 4 jacket-tipped (to reduce vein wall contact), 82 tulip-tipped (to prevent all vein wall contact), 83 or radial (to direct the laser energy laterally directly into the vein wall) 82 - with the advent of a single ring or double ring radial fibre 84 available. RFA devices can be monopolar 85 or bipolar 86 which pass electric current through the vein wall at radiofrequency rates to cause heating, or segmental where a coil of metal at the end of the device is heated by radiofrequency current and heat is passed into the vein wall by simple conduction.…”

Section: Treatmentsmentioning

confidence: 99%

Current Best Practice in the Management of Varicose Veins

Whiteley¹

2022

CCID

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This article outlines the current best practice in the management of varicose veins. “Varicose veins” traditionally means bulging veins, usually seen on the legs, when standing. It is now a general term used to describe these bulging veins, and also underlying incompetent veins that reflux and cause the surface varicose veins. Importantly, “varicose veins” is often used for superficial venous reflux even in the absence of visible bulging veins. These can be simply called “hidden varicose veins”. Varicose veins usually deteriorate, progressing to discomfort, swollen ankles, skin damage, leg ulcers, superficial venous thrombosis and venous bleeds. Patients with varicose veins and symptoms or signs have a significant advantage in having treatment over conservative treatment with compression stockings or venotropic drugs. Small varicose veins or telangiectasia without symptoms or signs can be treated for cosmetic reasons. However, most have underlying venous reflux from saphenous, perforator or local “feeding veins” and so investigation with venous duplex should be mandatory before treatment. Best practice for investigating leg varicose veins is venous duplex ultrasound in the erect position, performed by a specialist trained in ultrasonography optimally not the doctor who performs the treatment. Pelvic vein reflux is best investigated with transvaginal duplex ultrasound (TVS), performed using the Holdstock-Harrison protocol. In men or women unable to have TVS, venography or cross-sectional imaging is needed. Best practice for treating truncal vein incompetence is endovenous thermal ablation. Increasing evidence suggests that significant incompetent perforating veins should be found and treated by thermal ablation using the transluminal occlusion of perforator (TRLOP) approach, and that incompetent pelvic veins refluxing into symptomatic varicose veins in the genital region or leg should be treated by coil embolisation. Bulging varicosities should be treated by phlebectomy at the time of truncal vein ablation. Monitoring and reporting outcomes is essential for doctors and patients; hence, participation in a venous registry should probably be mandatory.

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“…Endovenous laser ablation (EVLA) in recent years has observed a trend towards using longer wavelength laser systems in combination with a radial-emitting fibre [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. Because of a higher coefficient of absorption in water for 1940 nm as compared to other wavelengths [ 15 , 16 , 17 , 18 ], and radial dissipation of the light energy with radial emitting fibres, the desired ablation of the vein wall can be achieved with lower power levels with thermal changes predominantly limited to the intima and media [ 19 , 20 ]. This translates in a clinical setting into high occlusion rates, low postoperative pain and low complication rates [ 14 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Prospects of Endovenous Laser Ablation (EVLA) Standardization—Mid-Term Results of a Four-Zone Dosimetry Guiding Tool for 1940 nm Laser

Setia

Dikic²,

Demhasaj³

et al. 2023

JCM

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Background: Heterogeneity regarding dosimetry and reporting of endovenous laser ablation (EVLA) mandates the development of a standardized protocol. This study presents the mid-term results of EVLA with 1940 nm-laser and radial-fibre, supported by a four-zone dosimetry tool. Materials and methods: Four anatomical dosimetry zones for great saphenous veins (GSV) and two for small saphenous veins (SSV) were defined with set power levels. Zone-1G (4 W) extended from the inguinal ligament to the apex of femoral triangle, Zone-2G (4 W) from the apex of femoral triangle to the upper border of patella. Zone-3G (3 W) from the patella to the tibial tuberosity. Zone-4G (2 W) extended from the tibial tuberosity to the ankle. Zone-1S from the sapheno-popliteal junction to the tibial tuberosity. Zone-2S from the tibial tuberosity to the ankle. Power was increased by 1 W for veins >10 mm and decreased by 1 W when fibre sticking was encountered. Pullback-velocity was max. 1 mm/s. Results: A total of 152 consecutive patients (185 procedures) were recruited. Mean follow-up time was 11.9 months. Mean linear endovenous energy density for GSV was Zone-1G:42 J/cm, Zone-2G:33 J/cm, Zone-3G:27 J/cm, Zone-4G:22 J/cm, Zone-1S:34 J/cm, Zone-2S:27 J/cm. Occlusion rates were 98.9% (1-month) and 93.7% (12-months). Complications at 1 M were low, namely laser-induced paraesthesia (LIP) 2.2% and endovenous heat-induced thrombosis (EHIT) 1.6%. Persistent LIP (12 M) was observed in 0.5%. Conclusion: The proposed four-zone guiding tool is a step towards standardizing dosimetry and documentation for EVLA with 1940 nm. This strategy shows good mid-term results with minimal complications. Long-term follow-up and application in further centres are necessary to prove its reproducibility. Such a guiding tool could improve the ability to analyse, compare and review different EVLA wavelengths and fibre types.

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Endovenous laser coagulation: asymmetrical heat transfer (modeling in water)

Cited by 8 publications

References 17 publications

Endovenous laser coagulation of varicose veins: evolution continues

Endovenous laser coagulation of varicose veins: evolution continues

Current Best Practice in the Management of Varicose Veins

Prospects of Endovenous Laser Ablation (EVLA) Standardization—Mid-Term Results of a Four-Zone Dosimetry Guiding Tool for 1940 nm Laser

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