Excisional Procedures: Liposuction





Key Points





  • If there is significant pitting (>8–10 mm in depth) of the lymphedematous limb, conservative treatment (combined physiotherapy) is indicated to remove the lymph and transfer the lymphedema to a non-pitting state, which indicates that any remaining excess volume consists of lymphedema-induced adipose tissue.



  • Liposuction for lymphedema is indicated when pitting is absent or minimal.



  • Tumescent solution (1–2 L) injected to subcutaneous tissue combined with tourniquet use decreases blood loss.



  • A power-assisted liposuction device is useful for shortening the operation time and decreasing the surgeon’s fatigue.



  • A custom-made compression sleeve and glove is applied intraoperatively.



  • The lifelong use (24 hours/day) of compression garments is mandatory for maintaining the effect of liposuction for limb lymphedema. Changes in the compression garments are required to adjust for limb volume changes.



Introduction


Liposuction techniques have proved to be a valuable tool in various aspects of reconstructive surgery. There is some controversy regarding liposuction as a treatment for late-stage lymphedema. While it is clear that conservative therapies such as complex decongestive therapy (CDT) and controlled compression therapy (CCT) should be tried in the first instance, options for the treatment of late-stage lymphedema that is not responding to these treatments are not so clear. Surgical procedures have been developed and described to address various clinical aspects of the pathophysiology of lymphedema. Microsurgical techniques and conservative treatment are promoted to provide physiologic drainage of excessive lymphatic fluid in the early stages of lymphedema. In late-stage cases though, adipose tissue deposition and sometimes fibrosis are the predominant manifestations of the disease process and cannot be removed by conservative treatment or microsurgical reconstructions. Surgical therapies aimed at adipose tissue removal can provide significant symptom relief for affected patients. Liposuction enables complete removal of the deposited adipose tissue, leading to complete volume reduction in late-stage lymphedema. In addition, liposuction techniques may be useful adjuncts after physiologic procedures to optimize surgical outcomes in early-stage lymphedema.


Concepts


Adipose Tissue Hypertrophy


Various possible explanations exist for the hypertrophy of adipose tissue seen in lymphedema. There is a physiologic imbalance of blood flow and lymphatic drainage, resulting in the impaired clearance of lipids and their uptake by macrophages. There is increasing support for the view that the fat cell is an endocrine organ and a cytokine-activated cell, and chronic inflammation may play a role in the alterations seen in the disease process. Also, previous research has highlighted the relationship between slow lymph flow and adiposity, as well as that between structural changes in the lymphatic system and adiposity. Other supported findings for adipose tissue hypertrophy include the following:




  • The findings of increased adipose tissue in intestinal segments in patients with inflammatory bowel disease (Crohn disease), known as “fat wrapping,” have clearly shown that inflammation plays an important role.



  • Consecutive analyses of the content of the aspirate removed under bloodless conditions using a tourniquet showed a high content of adipose tissue (mean, 90%).



  • In Graves ophthalmopathy with exophthalmos, adipocyte-related immediate early genes are overexpressed and cysteine-rich, angiogenic inducer 61 may play a role in both orbital inflammation and adipogenesis.



  • Tonometry can distinguish if a lymphedematous arm is harder or softer than the normal one. Patients with a harder arm compared with the healthy one have excess adipose tissue.



  • An investigation with volume-rendering computed tomography in 11 patients also showed a significant preoperative increase in adipose tissue of 81% in the swollen arm, followed by a normalization at 3 months paralleling the complete reduction of the excess volume.



  • Analyses with dual-energy X-ray absorptiometry in 18 women with postmastectomy arm lymphedema showed a significant increase in adipose tissue in the non-pitting swollen arm before surgery. Postoperative analyses showed normalization at 3 months. This effect was seen also at 12 months. These results paralleled the complete reduction of the excess volume.



  • A functional inactivation of a single allele of the homeobox gene prospero-related homeobox (Prox)1 led to adult-onset obesity due to abnormal lymph leakage from mispatterned and ruptured lymphatic vessels.



  • Parathyroid hormone–like hormone can inhibit adipogenesis and is downregulated both in active and chronic ophthalmopathy, indicating the possibility of an increased risk of adipogenesis.



  • Adipogenesis in response to lymphatic fluid stasis is associated with a marked mononuclear cell inflammatory response.



  • Lymphatic fluid stasis potently upregulates the expression of fat differentiation markers both spatially and temporally.



  • The underlying pathophysiology of lymphedema drives adipose-derived stem cells toward adipogenic differentiation.



  • Recent findings have shown that adipose tissue is also increased in the muscles of the lymphedematous arm.



Clinicians often believe that the swelling of a lymphedematous extremity is purely due to the accumulation of lymph fluid, which can be removed by the use of noninvasive conservative regimens, such as CDT and CCT. These therapies work well when the excess swelling consists of accumulated lymph but do not work when the excess volume is dominated by adipose tissue and related fibrosis. Conservative treatment and microsurgical procedures using lymphovenous shunts, lymph vessel transplantation, and vascularized lymph node transfer do not remove adipose tissue.


Regional Anatomy


The superficial lymphatic system consists of a fine dermal network draining to the lymphatics surrounding the major superficial veins, such as the cephalic vein or great saphenous vein. The deep lymphatic system is located under the muscle fascia and follows the major blood vessels. The superficial and deep lymphatic system drain to regional lymph node basins located along the lymphatic vessels (popliteal, inguinal fossae, and axilla), transporting the lymph through the lymph nodes on its way to the larger lymphatic vessels and ducts (the thoracic duct on the left side and the right lymphatic duct on the right side), which ultimately transports the lymph to the venous system by emptying into the venous angles in the neck (junction of the internal jugular vein and the subclavian vein).


Starling’s equation describes how the transcapillary exchange is regulated. Changes in the hydrostatic and colloid osmotic pressures affect the fluid exchange between blood and tissue, and thus the amount of interstitial fluid. Knowledge of this regulation is the basis of treating patients with edema (see Box 24.1 ).



Box 24.1

Starling’s Equation



<SPAN role=presentation tabIndex=0 id=MathJax-Element-1-Frame class=MathJax style="POSITION: relative" data-mathml='Jv=Kf((Pc–Pt)−Kd(Poc–Pot))’>Jv=Kf((PcPt)Kd(PocPot))Jv=Kf((Pc–Pt)−Kd(Poc–Pot))
Jv=Kf((Pc–Pt)−Kd(Poc–Pot))


Jv represents the fluid flow. Kf and Kd are filtration and osmotic reflection constants, respectively. Pc – Pt is the difference between the hydrostatic pressure between the capillaries and interstice. Poc – Pot is the difference in colloid osmotic pressure between the capillaries and interstice.



The equation shows that changes in hydrostatic pressure—as in venous stasis, or in protein concentration, as in liver, kidney, or bowel disease—are essential for fluid regulation on the capillary level. The proteins in the interstitial fluid are normally transported with the lymph. If lymph transport is obstructed, then the proteins stay behind and bind to liquid. Chronic inflammation likely plays a critical role in the formation of adipose tissue. Over time, the subcutaneous lymphedema becomes more compact and is dominated by adipose tissue, while the element of pitting usually decreases, even without treatment. The increased protein concentration in the interstice leads to increased fibrosis.


Patient Selection


Removal of excess adipose tissues via a surgical approach seems logical when conservative treatment has not achieved satisfactory reduction of the excess volume, and the patient has subjective discomfort of a heavy arm or leg.


Although basic in concept, multiple considerations are given to selecting the appropriate candidate for liposuction. Liposuction should not be performed in a patient with pitting edema, as it is dominated by accumulated lymph, which can be removed by conservative treatment.


The first and most important goal is to transform a pitting edema into a non-pitting one by conservative regimens like CDT or CCT. “Pitting” means that a depression is formed after pressure on the edematous tissue by the thumb, resulting in lymph fluid being forced into the surrounding tissues ( Fig. 24.1A ). To standardize the pitting test, one presses as hard as possible with the tip of the thumb on the region to be investigated for 1 minute, and the amount of depression can be estimated in millimeters. Very congested legs may need 3 minutes to show pitting. Other forms of swelling, which are dominated by hypertrophied adipose tissues, show little or no pitting ( Fig. 24.1B ).


Jun 23, 2021 | Posted by in CARDIAC SURGERY | Comments Off on Excisional Procedures: Liposuction
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