All About Liposuction: Part 1

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ALL ABOUT LIPOSUCTION: PART 1


Liposuction is the most common cosmetic surgical procedure worldwide. It provides effective contouring of the torso, extremities and jawline in properly selected patients. Tumescent liposuction, a local anesthesia technique, and superwet liposuction, a systemic anesthesia technique are the most common methods. The safety profile of both methods is excellent, but local anesthesia avoids the specific risks associated with general anesthesia. The most common complications of liposuction are contour irregularities and transient bruising. No technology to date appears to give superior results over conventional methods.

INTRODUCTION
The surgical removal of subcutaneous fat utilizing a blunt cannula attached to a suction device is termed liposuction. Synonymous terms include suction lipectomy and suction-assisted lipectomy (SAL). Lipoplasty, a broader term, defines any procedure that alters the contours of subcutaneous fat deposits by either the removal or addition of fat (liposuction and autologous fat transfer are both examples of lipoplasty). Lipolysis reflects the direct ablation of adipocytes by any method.

Liposuction is the most commonly performed cosmetic surgical procedure worldwide. Among North American women, breast augmentation is the only surgical procedure that approaches it’s popularity (1). At present, indications for liposuction are purely cosmetic and there appears to be no medical benefit from these procedures. Frequently treated areas include fat deposits of the torso, extremities and submandibular regions.

HISTORY
Liposuction evolved from blind sharp excisional procedures. In 1929, Charles Dujarrier, a French surgeon attempted the first contouring procedure of the inner thigh fat deposits introducing a sharp curette subcutaneously via a small skin incision (2). Tragically, hemorrhage ensued and the case ended with amputation. Blinded sharp excisional procedures were revisited several times in subsequent decades with various devices and they uniformly were abandoned due to bleeding-related complications. Giorgio Fischer, an Italian gynecologist, introduced suction as an adjunct to sharp curettage in the mid-1970s (3).

Ives Gerard Illouz of France, introduced the first technique of modern liposuction in the late 1970s (4). Unlike his predecessors, Illouz utilized blunt suction cannulas and high-powered suction to dislodge and remove subcutaneous fat. The technique utilized 10-mm cannulas and general endotracheal anesthesia. It was associated with significant blood loss which became the limiting factor in the extent of the surgery performed. The technique was later termed dry liposuction reflecting the fact that no fluids were injected into the targeted fat layers prior to suctioning. Subsequent modifications to the technique included the instillation of a small volume of saline, with or without hyaluronidase, into the fat layer as a lubricant to facilitate cannula motion; this became known as wet liposuction.

Pierre Fournier, a surgeon trained by Illouz, introduced syringe liposuction and syringe transplantation of the extracted fat. He coined the term liposculpture to describe his system (5). Further refinement of the wet liposuction technique involved the addition of epinephrine as a vasoconstrictor to the wetting solution by Gregory Hetter of Las Vegas, in the early 1980s (6).

The mid-1980s marked the modern era of hemostatic liposuction techniques. Central to these methods was the instillation of larger volumes of fluid with epinephrine into the targeted fat layers. Jeffrey Klein, an American dermatologist, introduced a purely local anesthesia technique termed tumescent liposuction in 1985 (7). Klein’s technique utilized lidocaine in larger volumes and higher total doses and smaller caliber cannulas than had previously been used and it continues to demonstrate the best safety profile for any method of liposuction surgery. Superwet liposuction, also introduced in the mid-1980s, is a technique utilizing general or regional anesthesia in conjunction with lower volumes and concentrations of lidocaine solution than tumescent liposuction. It displays excellent hemostasis and a degree of postoperative analgesia, but carries the risks associated with general or regional anesthesia.

WHO IS A GOOD LIPOSUCTION CANDIDATE?
The best candidates for liposuction are physically fit, weight stable and nonobese displaying localized fat deposits and minimal skin laxity. Patients in suboptimal health and those who require intense perioperative surveillance are not good prospects for this type of surgery.

A complete documented medical evaluation should precede any surgery of any kind. Any anatomic distortion (hernias, etc) with the potential to increase the risk of injury should be assessed and managed by appropriate means prior to surgery. Bloodwork analyses for signs of infection, anemia, blood clotting issues and liver disease are standard. Pregnancy testing is performed on the day of surgery. If the physician performing the medical evaluation is not the surgeon and is unfamiliar with liposuction, basic relevant details of the planned anesthetic agents and surgical interventions should be provided along with the request for medical clearance.

Medications, supplements, herbs and other substances with the capacity to thin the blood should be discontinued in advance of surgery. Substances which interact negatively with anesthetic agents and perioperative medications should also be avoided. If they cannot be discontinued or substituted, the surgical plan will need to be modified, delayed or withheld. Cigarette smoking is not a contraindication to liposuction, but smokers typically display a thinner dermis and less skin elasticity which both increase the likelihood of postoperative skin wrinkling.

Expectations and motivations need to be explored in depth when considering aesthetic procedures of any type. Unrealistic expectations will never be fulfilled by surgery even if executed to perfection by any medical or aesthetic standard. Liposuction is not a remedy for interpersonal conflicts. Similarly, patients seeking weight loss are best served by dietary counseling, the implementation of an appropriate exercise program and, if necessary, bariatric surgery. Liposuction does not generate long-lasting results or significant weight loss in the presence of poor eating habits and physical inactivity.

WHAT TYPES OF ANESTHESIA ARE USED FOR LIPOSUCTION?
Liposuction may be performed with local anesthesia with or without sedation, with epidural anesthesia or with general anesthesia. Each modality has its advantages, disadvantages, inherent risks and suitability for the unique demands of each operation and patient. In the United States, the majority of liposuction cases utilize lidocaine-based instillations into the targeted fat layers as the sole anesthetic (tumescent liposuction) or as an adjunct to general anesthesia (superwet liposuction). In Central and South America, the superwet technique is frequently performed with epidural anesthesia. Regardless of technique, the surgical team should be knowledgeable and prepared and the facility should be equipped to manage all potential adverse drug effects.

Tumescent local anesthesia, as introduced by Klein and as most commonly prepared, consists of lidocaine hydrochloride, sodium bicarbonate and epinephrine diluted in normal saline. The target concentration of lidocaine varies depending on the expected sensitivity of the surgical site, but varies little from patient to patient. The target volume of tumescent anesthesia at the surgical site is neither a fixed number nor a fixed ratio of fluid to estimated fat volume; it is determined by the achievement of palpable tumescence (uniform swelling) of the area, which is determined, in turn, by the elasticity , density and size of the targeted fat deposit. Lidocaine administered in this fashion displays a peak serum level 12 hours post-infiltration and complete elimination by 36 hours post-infiltration; it is metabolized through the liver (8) .

Superwet liposuction utilizes an instillation of the same ingredients as tumescent local anesthesia albeit at a lower concentration of lidocaine and a much lower volume since the surgical anesthesia is conducted by general or epidural modalities. The purpose of superwet infiltration of the targeted fat layers is primarily the hemostasis generated by the epinephrine in the solution and secondarily the postoperative pain reductiona produced by the lidocaine. In some instances, such as with lidocaine allergy, no lidocaine is employed in the solution.

THE ANATOMY OF FAT
Subdermal fat throughout the trunk and extremities exists in compartments within a connective tissue matrix termed the superficial fascial system (SFS) that extends from the subdermis to the muscle fascia (9). The SFS consists of horizontal sheets of membranous connective tissue connected by vertical and oblique septa. Scarpa’s fascia of the lower abdomen is an example of a well-defined horizontal sheet of the SFS. In other areas these sheets may be multiple and less distinct. As adiposity increases, the layers of fat within the SFS increase in thickness (10).

Within each layer, adipose tissue is organized into large visible subunits of varying size termed fat pearls. Fat pearls are composed of smaller ovoid subunits with a pasty consistency known as fat lobules and typically are not visible individually without magnification. Fat lobules consist of clusters of adipocytes and are supplied with capillaries and sometimes nerves (11). Fat tissue tissue demonstrate contains both mature adipocytes and adult stem cells; the latter have the capacity to form muscle and bone (12).

TECHNIQUES OF LIPOSUCTION
Basic techniques of modern liposuction utilize steel blunt suction cannulas of diameters ranging from 1 to 10 mm. Cannulas 2mm or narrower are termed microcannulas. Cannulas larger than 5mm are not commonly used when utilizing purely local anesthesia. Narrower cannulas offer more control whereas wider cannulas offer faster extraction. Cannulas are designed to be connected to either suction tubing or syringes. Suction tubing is connected to an aspiration pump.

Small skin incisions serve as entry ports for liposuction cannulas. These incisions are most commonly made with either skin punches or a scalpel and whenever possible are hidden within bikini lines, skin folds, scars or tattoos. Skin punch incisions are preferred when the surgeon wishes the sites to remain open for postoperative drainage.

The process of liposuction necessitates a back and forth motion of the cannula as suction simultaneously holds fat tissue in the lateral apertures of the cannula shaft. This action results in the avulsion of small parcels of fat from its connective tissue attachments creating tunnels through this matrix along the path(s) taken by the instrument. Tunneling creates narrow channels devoid of fat which collapse under the weight of the overlying tissue and is the mechanism by which contouring is achieved. The process typically does not damage blood vessels and nerves because they offer greater resistance to avulsion and because the cannula apertures do not have sharpened edges. The combination of fat and fluid removed as a result of this process is termed the lipoaspirate and over time it separates into a yellow supernatant fat layer and a blood-tinged infranatant fluid layer. When the back and forth cannula action is generated exclusively by the motion of the surgeon’s hand the process is called manual liposuction. When the cannula action is generated by a motorized handle, the process is known as power-assisted liposuction (PAL).

Control over the direction of the liposuction cannula is the cornerstone of both safety and an adequate cosmetic result. The nondominant hand plays a central role in this process by continuously confirming depth, direction and by detecting and protecting vital local anatomy. Under most circumstances, the motion of the cannula is parallel to the underlying muscle fascia and the process proceeds in horizontal planes starting in the deeper fat layers.

The endpoint of the liposuction process is variable and is determined by a combination of the patient’s wishes, the nature of the skin and fat layers, underlying musculoskeletal architecture and the need to develop symmetry. For example, when treating the inner or outer thigh fat deposits, a relatively large amount of fat intentionally is left behind to preserve the characteristic female contours while, when treating the abdomen very little fat is preserved in order to enhance the definition of muscle lines.

Total removal of the subcutaneous fat is never the goal of the procedure and if pursued is likely to produce irreversible and unsightly injury to the overlying skin. It is prudent to leave a thin layer of superficial subcutaneous fat intact as a means of protecting the delicate subdermal blood vessels and minimizing the risk of dermal trauma which most frequently manifests as skin wrinkling. At surgery, the thickness of the subcutaneous fat layers is determined by the pinch test - pinching the fat deposits between the fingertips as they are gradually reduced.

The upper limit of fat volume that may safely be removed in a single liposuction session has not yet been defined by science, but in some instances has been constrained by law. For example, in California, it is deemed unprofessional to extract more than 5,000 mL total aspirate volume per procedure outside of an acute care hospital (SB 450 Speier Bill, adopted August 31, 1999), and in Florida, it is prohibited to exceed 4,000 mL total fat aspirate volume in an office surgical facility in tumescent liposuction procedures (64B89-9.009, Standard of Care for Office Surgery, adopted February 17, 2000). In practical terms, purely tumescent liposuction inherently is limited by lidocaine dosing constraints. Nonetheless, it would be difficult to assert that the removal of a fixed volume of fat produces the same degree of surgical trauma in people of vastly different size and whether removed from a single area or multiple sites.

REFERENCES
  • 1.Cosmetic Surgery National Data Bank. 2008 Statistics. American Society for Aesthetic Plastic Surgery 2009. P. 3.
  • 2.Comiskey C. Cosmetic surgery in Paris in 1926: the case of the amputated leg. J Women’s History 2004;16(3):30-54.
  • 3.Fischer A, Fischer GM. Revised technique for cellulitis fat reduction in riding breeches deformity. Bull Int Acad Cosmetic Surg 1977;2:40.
  • 4.Illouz YG. Une nouvelle technique pour les lipodystrophies localisées. La Revue de Chirurgie Esthétique de Langue Française 1980;6(19):10-2.
  • 5.Fournier P. Liposculpture: Ma technique. Paris: Librairie Arnette 1990.
  • 6.Hetter GP. The effect of low-dose epinephrine on the hematocrit drop following lipolysis. Aesthetic Plast Surg 1984;8(1):19-21.
  • 7.Klein JA. Tumescent technique for liposuction surgery. Am J Cosm Surg 1987;4:263-7.
  • 8.Klein JA. Tumescent technique for regional anesthesia permits lidocaine doses of 35 mg/kg for liposuction. J Dermatol Surg Oncol 1990;16:248-63.
  • 9.Lockwood TE. Superficial fascial system (SFS) of the trunk and extremities: A new concept. Plast Reconstr Surg 1991;87(6):1009-18.
  • 10.Avelar J. Regional distribution and behavior of the subcutaneous tissue concerning selection and indication for liposuction. Aesthetic Plast Surg 1989;13(3):155-65.
  • 11.Klein JA. Subcutaneous fat: Anatomy and histology. In: Tumescent technique: Tumescent anesthesia and microcannular liposuction. Philadelphia: Mosby; 2000. P. 213-21.
  • 12.Kaminski M, Lopez deVaughn RM. The anatomy and physiology metabolism/nutrition of subcutaneous fat. In: Shiffman MA, DiGiuseppe A, editors. Liposuction: Principles and practice. Berlin: Springer; 2006. P. 17-25.
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Jersey City OB/GYN