Ex vivolaser lipolysis assisted with radially diffusing optical applicator

Abstract

Laser-assisted lipolysis has been implemented to reduce body fat in light of thermal interactions with adipose tissue. However, using a flat fiber with high irradiance often needs rapid cannula movements and even undesirable thermal injury due to direct tissue contact. The aim of the current study was to explore the feasibility of a radially diffusing optical applicator to liquefy the adipose tissue for effective laser lipolysis. The proposed diffuser was evaluated with a flat fiber in terms of temperature elevation and tissue liquefaction after laser lipolysis with a 980-nm wavelength. Given the same power (20 W), the diffusing applicator generated a 30% slower temperature increase with a 25% lower maximum temperature (84±3.2°C in 1 min; p<0.001) in the tissue, compared with the flat fiber. Under the equivalent temperature development, the diffuser induced up to fivefold larger area of the adipose liquefaction due to radial light emission than the flat fiber. Ex vivo tissue tests for 5-min irradiation demonstrated that the diffuser (1.24±0.15 g) liquefied 66% more adipose tissue than the flat fiber (0.75±0.05 g). The proposed diffusing applicator can be a feasible therapeutic device for laser lipolysis due to low temperature development and wide coverage of thermal treatment.

Microfocusing sapphire capillary needle for laser surgery and therapy: Fabrication and characterization

“…In order to introduce a fiber into tissues, it is often equipped with the needles or catheters, which should be removed before the exposure in order to avoid radiation losses [6]. Since the fibers are in contact with tissue, there is a problem of their damage during tissue coagulation and ablation; therefore, if possible, fibers should be protected with special introducers [12][13][14][15][16][17], which have to meet the list of requirements, that is, withstand high temperatures, demonstrate biocompatibility and chemical inertness, particularly in contact with in vivo tissues and blood, have high mechanical strength and transparency in the visible and near-infrared ranges.…”

“…Majority of instruments for laser therapy solve the problem of diffuse tissue irradiation [9,10,12,[33][34][35], because, on the one hand, it increases the treated volume of tissue, and, on the other hand, redistributes laser power and protects the instrument and the fiber from the overheating at particular points. Nevertheless, a problem of the precise irradiation of a small tissue area with a focused and collimated light beam also exists, for example, for the purposes of local ablative therapy [36,37], interstitial LTT of metastatic brain and liver tumors [38][39][40], or even optogenetics [41,42].…”

Optimization of sapphire capillary needles for interstitial and percutaneous laser medicine

“…8 These methods are minimally invasive (i.e., they limit the size of tissue damage and thus reduce the healing time of wounds, associated pain, and the risk of infection), which makes them rather attractive in the modern treatment strategies. PDT is extensively applied for cancer treatment, [9][10][11][12][13] whereas LTT provides treatment of varicose vein, 14 lipolysis, 15 epilepsy, 16 as well as cancers of the skin, 8 pancreas, 17 liver, 18 prostate, 19 lung, 20 breast, 21 and brain. [22][23][24] Both PDT and LTT admit interstitial application, turning into interstitial photodynamic therapy (I-PDT) [25][26][27] and laser interstitial thermal therapy (LITT), [28][29][30] aimed to deliver laser radiation directly to the internal region of interest (ROI) without an extensional surgical incision, using optical fibers.…”

“…2 In some cases, fiber can be protected from interaction with aggressive biological environments, as well as from overheating by special caps or domes. 15,32 Such protectors often enable circulation of a liquid coolant, 20,33,34 but complicate the instrument as well. An essential aspect of LITT is that a volume of the tissue ablation is limited mainly by the maximal power of light source that can be applied without a carbonization of surrounded tissues.…”

Spatial effect of conical angle on optical-thermal distribution for circumferential photocoagulation

“…Recently, diffusing optical applicators have been developed and investigated for the treatment of tubular tissue such as photodynamic therapy, nasopharyngeal carcinoma treatment [5], laser lipolysis [6], endovenous laser ablation [7], and tracheal stenosis treatment [8]. However, these developments are partly finished and their availability on the market is still unsatisfactory.…”