Advanced Techniques in Dermatologic Surgery - part 4

106 Sattler Figure 7 Endoscopic picture after complete liposuction of the lateral lower leg demon-strating of persisting fibrous tissue without adipocytes. fluid is removed, manual tissue stabilization (discussed below) performed by an assistant compensates the developing laxity of the skin turgor. Postoperatively, a thorough drainage of tumescent solution must be achieved by leaving the incision sites open and wearing compression garments. Figure 8 Formation of a subcutaneous scar 12 months after liposuction. Photograph taken during abdominoplasty. Liposuction 107 Technical Developments To obtain an atraumatic suction technique, technical developments led to an improvement of cannulas and liposuction-assisting devices. Manual Liposuction, 24-Hole Cannulas Ifcorrecttumescentlocalanesthesiaisperformed,thensuctioncanbedone withthin,blunt-tippedcannulas.Theconnectivetissuecanfurtherbespared when cannulas with multiple suction holes are used (24-hole cannulas). After building up the suction force, a number of holes (10–12,12–16) willbeoccludedbyfibroustissue.Theremainingholesstayeffectiveinlipo-suctioning, so the cannula cannot build up a higher suction force due to occlusion of the holes. As the suction force decreases, the holes that were previously blocked will reopen. When using two- or three-hole cannulas, it easily happens that all holes are occluded simultaneously. In this case, the suction force increases rapidly thus reinforcing the occlusion. Liposuction can be con-tinued only after cleaning of the cannula or destruction of the blocking tissue. The developed suction force in a 24-hole cannula is just strong enough to remove the fat cells but too weak to suck in and destroy fibrous tissue or vessels. In this way, blockage of the cannula and destruction of the connective tissue is prevented and the treatment is subtler. Ultrasound-Assisted Liposuction (UAL) To facilitate fat aspiration in difficult areas such as the male breast or back or in secondary sites, a number of new suction devices were devel-oped starting in the late1980s. In 1987, Scuderi and DeVita (12) and Zocchi (13) first described a method of homogenizing the fat with ultrasound waves. The suction cannu-laswereattached to an ultrasound generator and ultrasound waves sent into the tissue supposedly destroy the adipocytes. There are some severe disadvantages when using this technique. The cannulas must have a comparatively larger volume. A large number of seromas and skin burns and persisting hypo- or hyperaesthesias as a result of destruction of the myelin sheath of peripheral nerves were reported (14). There was even speculation about a potential carcinogenic risk. Therefore, the American Society of Dermatologic Surgery rates ultrasound assisted liposuction as an experimental method with no extended clinical use (15,16). Powered Liposuction/Vibrating Cannulas In 1995, Charles Gross (17), an ENT surgeon at the University of Virginia, described a new technique he used in liposuction of the neck called ‘‘lipo-shaving.’’ An engine-powered cannula with an integrated rotating blade was used to destroy adipocytes under direct visual or endoscopic control. 108 Sattler Figure 9 Demonstration of vibrating cannula technique. This idea started the invention of a new generation of cannulas, first with rotating blades but later with oscillating blades. The latest development is cannulas without blades but with a vibrat-ing grip that leads to vibration of the cannula when passing through the tissue (Fig. 9). One rationale behind the use of vibrating cannulas is the different inertness of various materials whereas, the cannula passes fibrous tissue without damaging it, the homogenized fat can be aspirated. The other aspect that aids this effect is the difference in velocity of the vibra-tion and the presence of the suction force. If the vibration speed is higher than the speed of the airflow of the suction, the suction can only withdraw the liberated, homogenized fat. The cannula will escape and spare the tissue structures that have tight attachments. Vibrating cannulas facilitate the treatment of fibrous or pretreated areas. Because they pass easily through the tissue and do not tangle with the fibers, they make the procedure more comfortable for the patient and the surgeon. Severe complications have not been reported. Further improvements of the cannulas and grips are expected, which will lead to a wide spread usage of this suction device as it shows greater benefits in achieving good operative outcome (18). Table 3 Sattler’s Tumescent Solution with Reduced Prilocaine Prilocaine 1% Epinephrine 1:1000 Sodium bicarbonate 8.4% Triamcinolon-acetonide 10mg Physiologic saline (NaCl 0.9%) 40.0mL 1.0mL 6.0mL 1.0mL 1000.0mL 1048.0mL solution 0.038% Liposuction 109 Table 4 Tumescent Solution After Schneider-Affeld and Friedrich Prilocaine 2% Lidocaine 2% Epinephrine 1:1000 Sodium bicarbonate 8.4% Triamcinolon-acetonide 40mg Physiologic saline (NaCl 0.9%) 10.0mL 10.0mL 0.66mL 6.0mL 0.33mL 1000.0mL 1026,99mL solution 0.037% Endoscopic Liposuction Liposuction is an operation without direct visual control. Endoscopic liposuction can be used to visualize what is happening in the subcuta-neous space during liposuction. This method helped to control the tech-nique and quality of liposuction and to give a further understanding of physiodynamic processes in the adipose tissue. It is not routinely used clinical procedure, but has helped in the development of new, useful lipo-suction devices. Refinements of the Tumescent Solution In the course of time, the original Klein tumescent solution was modified by various working groups. Wefirstreplacedlidocaineaslocalanestheticwithprilocainebecauseof its lower systemic plasma levels, which is relevant when using large volumes. As a result of clinical observations, prilocaine could be reduced by 20% from the initial 50 mL/L to 40 mL/L, which resulted in a reduced local anesthetic concentration of 0.038% (Table 3). Table 5 Volumes of Tumescent Solution: Comparison of 1992 and 1997 Recommendations Abdomen Hips (both sides) Waist (both sides) Lateral thigh (both sides) Ventral thigh (both sides) Medial thigh (both sides) Knee (both sides) Male breast (both sides) Neck 1992 1997 800–1000mL 5000mL 400–1000mL 5000mL 400–1000mL 3000mL 500–1200mL 4000mL 600–1200mL 4000mL 255–700mL 3000mL 200–500mL 2000mL 300–800mL 3000mL 100–200mL 800mL 110 Sattler In clinical trials, Schneider-Affeld and Friedrich combined lido-caine and prilocaine to decrease the side effects of a single agent. Their solution is shown in Table 4. As a consequence of reduction of the local anesthetic concentration and the growing knowledge of delayed absorption, the quantities of tumescent solution used in one session could be raised. The possibility to use more quantities of tumescent solution widens the therapeutic range. Today, up to 6 liters of tumescent solution are used in one session. Figure 10 Modern liposuction equipment with infiltrating pump connected to a Stenger distributor, a suction system, and warming devices for tumescence solution. ... - tailieumienphi.vn