Non-invasive Skin Tightening The gold standard for skin laxity - TopicsExpress



          

Non-invasive Skin Tightening The gold standard for skin laxity is surgical redraping. The gold standard for facial skin tightening is ablative laser resurfacing. But, they require long downtime and there is high risk of side effects. Non-ablative technologies: induce thermal injury to the dermis without epidermal vaporization. Surface cooling may be used to protect the epidermis. Thermal collagen remodeling All skin-tightening devices work by delivering heat energy to the skin or underlying structure. This creates mechanical and biochemical effects. Mechanism of action: When collagen fibers become heated to specific temp. the intermolecular hydrogen bonds become broken Collagen fibers contract (they become thicker & shorter). Delayed remodeling (neocollagenesis) via wound healing response. If too much heat is delivered: collagen fibers will denature completely, and scarring will occur. If too little energy delivered: no tissue response. Collagen contraction is determined by temp. and exposure time. Optimal collagen shrinkage temp.: 57-61 C. Optimal exposure time = several seconds. Imp. Rule: for every 5C decrease in temp. a tenfold increase in exposure time is needed to achieve equivalent amount of collagen contraction. Thus: if exposure time is in msec. shrinkage temp. >85C. And: if exposure time is over several seconds shrinkage temp.at 65C. non-ablative therapies : 1. Initiate new collagen formation. 2. Prevent photodamage progress. Pt./physician must expect moderate improvement. Dark skinned candidates cant be treated with non-ablative modalities that selectively heat melanin. Most common side effect is hyperpigmentation. (Resolves after 4-8 weeks with appropriate app. of suppressors of melanin synthesis) Mid IR laser (minimize direct melanin targeting) can be used in pt. with darker skin types. However, risk of thermal damage can occur for high fluence. Use non-cryogen skin cooling. Fillers & botox can be combined with non-ablative laser/light. Non-ablative resurfacing should be performed last, to min. the risk of neurotoxin diffusion which should cease by 1 hr. after the injection. Contraindications: 1. Active infection. 2. Recently used isotretinoin/Oral retinoids. 3. Pacemakers. 4. Recent rejuvenation Procedures. Pt. selection: Most promising pt. are young pt. with lesser degree of skin laxity. Pt. with skin laxity without significant muscular attachment can get very good results. Very old pt. with severe sagging & wrinkles are not suitable for non-surgical ttt. Select pt. who wants moderate degree of tightening with little/no downtime. It is essential to take standardized photos before & after ttt. Younger pt. respond better than older pt. wrong. Response to skin tightening devices is determined by the skin quality, not the age of the pt. Older pt. with bad skin quality are less amenable to heat induced tissue tightening, because heat-labile collagen bonds are replaced by irreducible multivalent cross-links as the tissue ages. Pt. must know that max. results are slow (3-6 month.) Clinical studies show significant improvements but most pt. show mild improvements. The key to success is related to pt. selection & management of the expectations. Pt. expectation management (realistic expected results): Small no. of pt. get no results. Ttt is not substitute of facelift. Non-ablative skin tightening alone is not effective for the textural aspects of photoaging including wrinkles & pigmentary alterations. Pt. expect at least a period of year or more before touch-up ttt are required. Results should not be expected to be similar to those seen after surgical or even ablative techniques. Physicians must appreciate the limitations of each device. No. of ttt required is not standard for all cases. Long term improvements differ from pt. to the other. Devices for Non-invasive Skin Tightening: I. Rf RF energy is energy in the electromagnetic spectrum ranging from 3 KHz to 300 MHz. When RF electric current flows in tissue, Heat is generated from natural resistance (impedance) of the tissue as governed by ohms law. i.e: electrical energy is converted into heat energy. The amount of heat generated is relative to frequency, amount of current, time of exposure and the impedance of the tissue. Generated heat becomes distributed through three dimensional volumes of tissue at controlled depth. Tissue is made up of multiple layers, each layer has different resistance to RF current. Structures of high impedance are more susceptible to heating. Note: fat, bone & dry skin have high impedance electric current flow around them rather than through them. But: WET Skin: has much lower impedance, thus, allow more flow of current. Thus, the use of coupling fluid/gel is imp. with RF procedures. Imp. Note: tissue temp. influences conductivity & electrical current distribution. Rule: every 1C inc. in tissue temp. Lowers skin impedance by 2%. Thus: surface cooling will inc. resistance to electric current near the epidermis & the current will be driven inside the tissue, increasing the penetration depth. Prewarmed target structures will have less impedance, thus, greater current flow through them. Therefore some RF devices are accompanied with some sort of light source to selectively heat target structures selective RF !!! Best pt. for RF skin tightening: Mild to moderate solar elastosis & skin laxity. a. MONO-polar RF : Deliver radiofrequency energy to skin which will convert into heat energy because of the tissue natural resistance. Tissue resistance to current flow results in uniform volumetric heat produced at the dermis & subcutaneous fat. Electric current passes through a single electrode through the whole body to a grounding pad. It targets deeper, volumetric heating via the rotational movement of water molecules in the alternating current of the electromagnetic field. Thus: high density of power close to electrodes surface with the potential of deep penetration of tissue heating. Collagen contracts immediately & continues for 6 month. The more heat produced, the more collagen formed & the greater the pain generated. Topical anesthesia is required to dec. pt. discomfort. Surface cooling is used to protect the outer layers of skin. If the heat is too much: denaturation of contractile proteins, fat necrosis, burn & scar. Lower energy & multiple passes decreased the RF-associated discomfort. Tissue arcing: occur if the handpiece is not properly placed in contact with the skin burn & scar. Thermage FDA approved in 2006 Mechanism: lysis of the adipocyte membrane. Uses capacitive coupled electrode at 6 Mhz. (Capacitive electrode allows electric energy to be distributed across large area so that the generated heat energy will not be concentrated in a small spot at the contact surface, thus protect the skin from burning.) Disposable adhesive membrane acts as grounding pad to close the cct. This device is very painful if used with high energy and may make fat necrosis or atrophic scars. Thus, user must use low power and make multiple passes to achieve the best results. Results: very good skin tightening of face, eyelids, abdomen & extremities. b. FRACTIONAL RF Electric current passes between 2 electrodes at a fixed distance. Here: current flow is more controlled than mono-polar RF. Depth of penetration = half the distance bet. the 2 electrodes. Depth of penetration also depends on the type of tissue serving as the conduction medium. USES a microneedle electrode array to deliver bi-polar Rf energy into the reticular dermis while bypassing the epidermis and the papillary dermis. E-PRIME: 32 microneedles, 250 Um diameter, 1.25 mm spaced, 6mm long, 3mm is insulted. Each needle is independently powered by the generator. RF is applied for time that is enough for the temp. conduction to expand the damage zone in all directions. Epidermal cooling is achieved via integrated thermokinetic cooling bar on the applicator. Real temp. monitoring maintain a target temp. of approximately 70C regardless of varying skin conditions . Results are satisfying for pt.s c. Vac. Assisted bi-polar RF: Vacuum suctions a fold of skin in alignment bet. the 2 electrodes of RF. Vacuum suction inc. blood flow & make mechanical stress on fibroblasts leading to increased collagen formation. Adv.: 1. avoid non-targeted structures (muscle, fascia & bone) 2. overcome the limited depth of penetration of bi-poar RF & reduce RF energy. 3. max. results 4. max. pt. comfort during the session. Results: 1. Significant improvement in skin texture. 2. Short term tightening 3. Long term tightening. (due to wound healing response) Devices = aluma by luminous, velashape by syneron, ultrashape V3 by ultrashape, tite FX by invasix. Velasmooth/velashape (for body only) IR light (700-2000 nm) + vac. + bi-polar RF + ROLLERS During treatment the applied suction pulls the skin into a chamber in the middle of the treatment cavity, where the skin is exposed to IR light and RF while its surface temperature is being monitored. Mechanism of action: Optical IR energy targets mainly the dermal water the RF energy targets the hypodermis by controlled thermal stress. Applying thermal energy to the dermis causes dermal tightening and contraction & activates the dermal fibroblasts (the cells that produce collagen) to stimulate and promote neocollagenesis (new collagen formation). Neocollagenesis is potentiated by increased dermal vascularity secondary to the thermal stress induced. The vacuum potentiates neocollagenesis via the mechanical stress imposed on dermal fibroblasts. Neocollagenesis and collagen contraction further contribute to enrichment and strengthening of the otherwise loose connective tissue fibrous septae. Vacuum and mechanical massage increase blood vessel and lymphatic circulation and lymphatic drainage The resulting simultaneous increase in the dermal collagen and ground substance content, connective tissue architecture, and the decrease in subcutaneous fat tissue volume allow for improvement in skin laxity. Results: moderate skin tightening. ULTRASHAPE (for body only): Version 3 (2010) : Advanced focused ultrasound technology and vacuum-assisted radio frequency. Providing a good solution for skin tightening. Treatment protocol: 1. Tightening and tissue preparation with suction-coupled RF. preheating the tissue increases local blood circulation and creates mild edema producing a more “wet environment” in the target tissue enhance the cavitational mechanical effects of focused ultrasound treatment. 2. Immediate fat cell destruction to reduce localized fatty areas with the focused ultrasound. 3. Tightening and expedited fat clearance with the focused ultrasound To increase blood circulation and stimulate localized lymphatic drainage and accelerate fat clearance for even better and more consistent results. Proper patient positioning is a critical factor for a successful treatment. Complications: erythema, blistering & dermal erosion. Tite FX (for body only) Tite FX = vac. + bi-polar RF + hi-voltage electroporation pulse handpiece for body (contour+cellulite) handpiece for face (tightening) TiteFX uses suction coupled RF to preheat the dermis and first 15 to 20 mm of fat. and uses a precise thermistor built inside the suction cavity to monitor the uniform and even skin temperature and suction distribution. The device is very fast the temperatures very uniform the treatment is tolerable no “hot spots” no pain d. HYBRID (mono+bi) Deliver different depths of current to the skin. Mono for deep heating. Bi for superficial heating It makes tissue tightening & volume reduction. Devices = accent by alma. e. Combined RF & optical energy devices: Two forms of energy act synergistically to generate heat. Target structures -that are Prewarmed with the optical energy- will have lower impedance & will be selectively more heated with the RF current. Adv.: less RF energy is required to make proper collagen denaturation and remodeling. Imp. Note: all skin tightening devices using RF, US, & IR light are safe in all skin types except technologies that use optical component absorbed by the pigment (ipl). Fluence is inc. according to pt. pain tollerence immediate erythema & edema. RF+Diode light : moderate improvement after 3 month, but improvement slightly reduced after 6 month. RF+IPL: moderate improvement, but scars & crust may occur. RF+IR: moderate improvement. Devices = galaxy, aurora, Polaris, refirme, by syneron II. Light therapy a. IR Laser Some non-ablative lasers with wavelength in the near IR spectrum (target water) are marked for facial wrinkles. 1064 nm chromophores: melanin, hemoglobin, water. They are ineffective when used on body for skin tightening.(nd:yag) Next generation of these devices have longer wavelengths and are more effective when used on body for skin tightening. 1320, 1440, 1450, 1540 nm primary chromophore : water. Moderate improvement of wrinkles & skin laxity. Combing laser with epidermal ttt gives betters results & higher patient satisfaction. b. IR Light Broad band IR 800-1800 nm IR targets water causing collagen denaturation collagen remodeling. To get best results : Use low fluence with high no. of pulses , 2 passes for full area & extra passes on areas that need immediate contraction . Sess. is not painful. IR gradually heats the dermis - with (pre, parallel & post) cooling to protect the epidermis. Immediate results are visible after first sess., though, multiple ttt are required to get optimal results. Clinical skin tightening doesnt correlate with immediate positive histological findings. Full clinical effect take weeks or months to be reached because of the delayed wound healing response. Minor erythema may appear, also few blisters may be observed. Devices : 1. titan by cutera (1100-1800 nm) 2. starlux IR by palomar (fract. 850-1350 nm). 3. Skintyte by sciton (800-1400 nm) c. IPL : Ipl mechanism: use selective photothermolysis to induce collagen remodeling. Heating of water in the dermis tissue contraction improvement in skin laxity. The subsequent inflammatory reaction induced dermal remodeling. Deliver energy deep in the dermis creating volumetric uniform heating of the tissue. Result = skin tightening after 3-6 months after treatment. d. LLLT (LLLT) is defined as treatment with a dose rate that causes no immediate detectable temperature rise of the treated tissue and no macroscopically visible changes in tissue structure. Laser dosage Unit is expressed as joules per centimeter squared, and the dosage is calculated as the laser power measured in milliwatts, multiplied by treatment time in seconds, and divided by the area of the laser spot directed toward the tissue. Photobiomodulation via an external light delivery system represents a unique and misunderstood sector of medicine. Studies continually affirm that light has the capacity to penetrate the skin barrier and trigger real and measurable photochemical responses within the targeted tissue. A report documented improved contour and skin retraction. Well selected patients are generally satisfied with results. under promote & guarantee the min. e. LED No pain Large surface area can be treated simultaneously LED = blue, yellow, red, green & IR. POWER = mW. MECH.: unclear, photomodulation of cell receptors. Non-thermal interaction with extracellular matrix & fibroblast remodel existing collagen, inc. collagen production by fibroblasts, inhibit collagenase activity rhytid reduction. Yellow (588 nm) improves pore size, skin tone & texture: clinical trialsno significant skin changes. 633 nm , 3 ttt./week for 4 weeks moderate wrinkle improvement. III. US High intensity focused US Friction is created between molecules leading to secondary generation of heat. Theoretically, this leads to immediate tissue contraction & delayed collagen remodeling with coagulative change limited to the focal region of the US field. In reality, cellular changes depend on the rise in temp. & the exposure duration & range from total necrosis to ultrastructural cell damage with modulation of cellular cytokine expression. Frequency in MEGA Hz (not khz to avoid cavitation effect) range with msec. pulses at low energy (max. 10 j). Depth & volume of the thermal lesions are determined by: a. The preset focus depth. (focus @ mid to deep dermis) b. Frequency of the probe (High frequency superficial effect thinner skin) (Low frequency deep effect thicker skin.) c. Characteristics of the tissue being treated. *** Adv.: a. high penetration depth b. Controlled focal tissue injury= selective absorption of US energy in the area of geometric focus of the beam. c. No secondary scatter /absorption in the dermis/epidermis. d. Long term results. Results may be seen 90 days after the treatment. Significant improvement in brow elevation, nasolabial folds & jaw line. Histological evaluation showed greater dermal collagen with thickening of the dermis & straightening of elastic fibers in the reticular dermis after treatment. Temporary nerve side effects may occur. Optimal treatment parameters are still being developed. Devices = ULTHERA.
Posted on: Sat, 25 Jan 2014 12:25:01 +0000

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