Mathematical modeling of 980‐nm and 1320‐nm endovenous laser treatment

Mordon, Serge; Wassmer, Benjamin; Zemmouri, J.

doi:10.1002/lsm.20476

Cited by 63 publications

(58 citation statements)

References 39 publications

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“…−7 m 2 /s, a typical value for blood [8], a=0.2 mm, i.e., taken as equal to the radius of the fiber, L 0 =1 cm, V=1,073 K (800°C) or 1,273 K (1,000°C), a venous radius of r=1.5 mm (assuming that the diameter of the treated vein is the diameter of the catheter, in our case 3 mm, caused by the tumescent anesthesia that increases the perivenous pressure), but also 2.5 mm (Fig. 3), the vein radius used in the experiments by Disselhoff et al [9], and close to the tube radius of 3 mm used by Proebstle et al [11], and v=1 mm/s, 2 mm/s, and 3 mm/s.…”

Section: Figure 2 Shows Some Results For κ=14×10mentioning

confidence: 99%

“…Nevertheless, it cannot be excluded that they are another contributing EVLA mechanism. Although Mordon et al [8], Disselhoff et al [9] and Fan and Anderson [12] provided arguments against the thermal efficacy of steam bubbles, the further unraveling of the complex mechanisms of EVLA calls for identification of the thermal consequences of propagating and collapsing steam bubbles, a project in progress in our group.…”

Section: Discussionmentioning

confidence: 99%

“…First, direct absorption of the laser light transmitted through the fiber tip, scattered by the blood and reaching the venous wall, which was previously discussed by Mordon and colleagues [8]. Second, heat diffusion from the hot fiber tip towards the venous wall, which consequences have not been considered so far.…”

Section: Hypothesismentioning

confidence: 99%

“…Despite consensus on the requirement of a thermally injured venous wall, the uncertainty relates to the mechanism or mechanisms that cause the thermal injury. Here, direct absorption of the scattered laser light by the venous wall [8,9], steam bubble generation at the fiber tip and their subsequent propagation to, and distal collapse at, the wall [10,11], and direct contact of the fiber tip with the wall [12], have been suggested as contributing mechanisms. Notably, however, exceedingly high temperatures of the fiber tip during laser irradiation in blood have also been reported, at 810 nm [9,13], 980 nm [10], and 1,064 nm [14].…”

Section: Introductionmentioning

confidence: 99%

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Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

et al. 2009

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Lower-extremity venous insufficiency is a common condition, associated with considerable health care costs. Endovenous laser ablation is increasingly used as therapy, but its mechanism of action is insufficiently understood. Here, direct absorption of the laser light, collapsing steam bubbles and direct fiber-wall contact have all been mentioned as contributing mechanisms. Because fiber tips have reported temperatures of 800-1,300°C during endovenous laser ablation, we sought to assess whether heat conduction from the hot tip could cause irreversible thermal injury to the venous wall. We approximated the hot fiber tip as a sphere with diameter equal to the fiber diameter, having a steady state temperature of 800°C or 1,000°C. We computed venous wall temperatures due to heat conduction from this hot sphere, varying the pullback velocity of the fiber and the diameter of the vein. Venous wall temperatures corresponding to irreversible injury resulted for a 3 mm diameter vein and pullback velocities <3 mm/s but not for 5 mm and ≥1 mm/s. The highest wall temperature corresponded to the position on the wall closest to the fiber tip, hence it moves longitudinally in parallel with the moving fiber tip. We concluded that heat conduction from the hot fiber tip is a contributing mechanism in endovenous laser ablation.

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Section: Figure 2 Shows Some Results For κ=14×10mentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Hypothesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

et al. 2009

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“…Early success with this device prompted development of other devices that supplied wavelengths (WLs) more specific to the hemoglobin chromophore (810-, 940-, and 980-nm devices) in an effort to achieve 100% saphenous vein closure (2)(3)(4)(5)(6)(7). In contrast to these laser systems, the 1320-and 1470-nm WL laser systems affect interstitial water (8,9). Goldman (6) introduced the 1320-nm WL, which better exploits water as the energy-absorbing molecule.…”

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confidence: 99%

The effect of laser wavelength on postoperative pain score in the endovenous ablation of saphenous vein insufficiency

Duman

Yıldırım²,

Saba³

et al. 2013

Diagn Interv Radiol

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ORIGINAL ARTICLE PURPOSE Endovenous laser ablation has replaced surgical methods in the treatment of saphenous insufficiency. The aims of this study were to compare the effectiveness of 1470-and 980-nm wavelength (WL) laser systems, to compare the postoperative complication rates, and to determine the effect of laser WL on postoperative pain scores. MATERIALS AND METHODSBetween October 2010 and November 2011, 79 consecutive patients with saphenous vein insufficiency were examined. The patients who received the 980-nm treatment were defined as Group 1; 54 extremities of 47 patients were treated in this group. The patients who received the 1470-nm treatment were defined as Group 2; 36 extremities of 32 patients were treated in this group. RESULTSEarly technical success was 100% in both groups. Both major and minor complications were seen in Group 2. The complications in Group 1 were mostly major; however, three minor complications were reported in this group. The complication rates of the two groups were not significantly different. There was no statistically significant difference between the pain scores of the two groups. CONCLUSION Early postoperative pain was the major factor that impaired quality of life. There was no relationship between the postoperative pain scores and laser WL or energy density. The laser WL did not affect technical success or occurrence of complications. Use of a suitable energy density resulted in complete occlusion in all patients with saphenous vein insufficiency. Lower extremity venous insufficiency is a very common medical condition that affects approximately 25% of females and 15% of males (1). Great saphenous vein reflux is the most common underlying cause of symptomatic varicose veins. Other causes are reflux in other truncal veins, such as the small saphenous vein, the anterior or posterior thigh circumflex vein, the Giacomini vein, and perforating veins. Treatment options for varicose veins include conservative management, minimally invasive procedures, and surgery.In 1999, Salat (2) first reported the delivery of endoluminal laser energy with an 810-nm diode laser for the treatment of varicose veins. Early success with this device prompted development of other devices that supplied wavelengths (WLs) more specific to the hemoglobin chromophore (810-, 940-, and 980-nm devices) in an effort to achieve 100% saphenous vein closure (2-7). In contrast to these laser systems, the 1320-and 1470-nm WL laser systems affect interstitial water (8, 9). Goldman (6) introduced the 1320-nm WL, which better exploits water as the energy-absorbing molecule. Two comparative studies indicated that patients treated with water-specific laser WLs reported less postoperative pain, used less painkillers, and were less likely to have ecchymosis (8, 10).There is increasing focus on reducing postoperative pain and bruising, while maintaining high saphenous vein ablation rates. Because the 1470-nm WL is absorbed by water at a level 40-times more than the 980-nm WL, the manufacturer hypothesized that it woul...

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Endovenous Laser Therapy – Application Studies, Clinical Update, and Innovative Developments

Sroka

Schmedt

2012

Handbook of Biophotonics

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Endovenous laser therapy (ELT) was introduced in clinical practice as a therapy for incompetent veins about 10 years ago. One characteristic of ELT is the broad spectrum of different treatment protocols by means of a variety of laser systems together with manifold application forms. A variety of light dosimetric concepts are under investigation. Endoluminal laser treatment of incompetent great saphenous veins of patients suffering from varicosis is a promising new procedure offering fewer side effects than conventional surgical stripping methods. Clinical results with effective, relatively pain‐free occlusion of incompetent varicose veins have been observed, and also undesired side effects such as ecchymosis, phlebitis, and recanalization. In recent years, systematic experimental investigations and the analysis of clinical results have increased the understanding of the interrelation between the clinical and physical aspects, followed by continuous optimization of ELT. The use of infrared wavelengths and radial irradiation concepts, together with continuous moving of the optical fiber, seems to reduce possible side effects. In this way, ELT treatment becomes a more standardized effective method for the treatment of varicose veins. In future, randomized controlled studies are required to compare optimized ELT treatment with other endoluminal modalities and conventional surgery.

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Mathematical modeling of 980‐nm and 1320‐nm endovenous laser treatment

Cited by 63 publications

References 39 publications

Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

Heat conduction from the exceedingly hot fiber tip contributes to the endovenous laser ablation of varicose veins

The effect of laser wavelength on postoperative pain score in the endovenous ablation of saphenous vein insufficiency

Endovenous Laser Therapy – Application Studies, Clinical Update, and Innovative Developments

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