Lymphoscintigraphic Appraisal of the Lower Limbs After Liposuction

Methods 

Radiologic Procedure 

The patients underwent two lymphoscintigraphic tests using the same methodology. The first test was conducted one week before liposuction and the second was conducted three months postoperatively. The examinations were performed at the Department of Nuclear Medicine of the Federal University of São Paulo Medical School.

For the lymphoscintigraphic examination, 37 megabecquerels (MBq) of technetium-99m–labeled dextran 70 was injected subcutaneously into four areas that were predefined by the surgeons: the right lateral (area 1), right medial (area 2), left medial (area 3), and left lateral (area 4) surfaces; 9.25 MBq (250 μCi) of dextran 70 was injected into each area (Figure 1). A gamma camera attached to a computer with a low-energy collimator was used to capture the lymphoscintigraphic images.

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Figure 1. Areas predefined by the surgeons. Area 1, Right lateral surface. Area 2, Right medial surface. Area 3, Left medial surface. Area 4, Left lateral surface.

The patients were placed in the supine position and the head of the equipment was placed over the injected and pelvic regions. Immediately after injection of the radiopharmaceutical, an initial dynamic study lasting one hour was performed (one frame per minute). At the end of this dynamic study, the images taken during the last five minutes were grouped so as to acquire an initial static image at one hour. After this first static image, the patients were released and asked to return at the end of another hour to obtain a second static two-hour image taken with the patient in the same position. Curves of activity over time in the areas of interest, traced over the sites of injection, were obtained. From these, the half-time (T½) of drainage (the time necessary to reduce the initial radioactivity by half) and the percentage of elimination from each area starting from the static images (that is, clearance of the radiopharmaceutical in each area) were also obtained.

The percentage indexes of clearance of each area were calculated using the following formula:

The negative clearance is less clearance of the radiopharmaceutical from the region. The Wilcoxon signed-rank test was used for the comparison of differences between measurements.

Results 

The quantitative analysis comparing calculation values of the average time of the radiopharmaceutical acquisition curve and clearance in the areas of lymphoscintigraphic interest both before and three months after liposuction using the Wilcoxon signed-rank test did not show statistically significant results (Table).

Table. Wilcoxon signed-rank test analysis of T½ and clearance of radioactivity of the determined regions pre- and postliposuction per lymphoscintigraphic examination

	Determined regions examined for percentage of clearance	Preliposuction examinations × postliposuction examinations, calculated P (critical z = 1.96)
	Area 1
	T½	.866
	One hour, %	.866
	Two hours, %	.398
	Area 2
	T½	.735
	One hour, %	.735
	Two hours, %	.310
	Area 3
	T½	.735
	One hour, %	1.00
	Two hours, %	.612
	Area 4
	T½	.499
	One hour, %	.398
	Two hours, %	.866

T½, time necessary to reduce initial radioactivity by 50%; critical Z, statistical parameter.

Discussion 

Liposuction was first proposed in Italy by Giorgio Fischer in 1974 and was later used in aesthetic surgery by the French plastic surgeon Yves Illouz in 1978.3 Since that time, the techniques and materials employed in conventional liposuction have undergone modifications aimed at reducing the risk, trauma, and bleeding associated with the procedure and improving the aesthetic results. These alternative techniques include vibroliposuction and ultrasound-assisted liposuction.4 No matter the method used, the objective is to remove adiposities located in various regions of the body.

In this study, conventional liposuction was employed because, in our opinion, it involves less risk and trauma and therefore results in lower levels of blood loss while providing good aesthetic results. Conventional liposuction was performed after infiltration of a vasoconstrictor. Lysis was promoted with removal of adipose cells by horizontal movements of a cannula connected to a suction pump.

Some injury to both the lymphatic structures and the subcutaneous cellular tissue is unavoidable with this procedure and these injuries are associated with bleeding and edema. In most cases, edema regresses in about three months, but it may persist for a longer period of time in some patients. However, the degree of injury to the lymphatic structures caused by the cannula, the suction procedure, or both is difficult to measure, which is what motivated us to perform this study.

Assessment of the degree of injury to the lymphatic system is important because of the susceptibility of the system to the trauma associated with liposuction, the irreversibility of any injuries that occur, and, consequently, the possibility of some degree of lymphedema.

The lymphatic system of the lower limbs and other body areas display similar anatomic and histologic characteristics. Anatomically, this system originates in the microcirculation within the lymphatic capillaries, which are similar to the blood capillaries. These lymphatic capillaries coalesce and form the vessels and pre- and postnodular lymphatic collectors, depending on their relationship with the lymph nodes. The lymph collectors have valves, so that the segment delimited by a proximal and a distal valve configures the motor unit of the system (termed the lymphangion), which propels the lymph.5 The lymph is transported to the lymphatic trunks from the vessels and collectors and later to the ducts, reaching the blood stream through the venous system. Histologically, the basal membrane of the lymphatic capillaries is either fragile or lacking and displays a unit of elastic fibers that form filaments. The latter permit broad openings between the junctions of the endothelial cells that, when open, allow for the absorption of large molecules. When closed, they admit the passage of fluids and small molecules. Eighty percent of the lymph vessels run along the internal surface of the thigh, and 20% are on the lateral surface.5

The objective of our investigation was to use lymphoscintigraphy to evaluate the lower limbs after liposuction, because this region has the largest deposits of localized adiposities. Lymphoscintigraphy was the method of choice for this evaluation because it permits visualization of the lymphatic system and analysis of its function. In addition, it was not very invasive and it was safe, easy to repeat, and well-tolerated by patients.6, 7, 8, 9, 10 This procedure has also been used to evaluate the lymphatic function both before and after treatment for lymphedema, using either a pneumatic compression pump10, 11 or by manual lymph drainage.12, 13

Another method for the evaluation of the lymphatic system is lymphography. Its complications, however, are well-known and include allergic reactions to the contrasts in general, pulmonary complications, accidental intravenous injections, extravasation and perivenous injection, pulmonary embolism, infection, and lymphangitis. In addition, lymphography is performed in stages, including surgical dissection of the lymphatic channels at the extremity, so it is a more invasive examination.14, 15, 16, 17

The choice of a three-month postoperative period for lymphoscintigraphy was based on the fact that in most cases, the edema has regressed by this time. Lymphoscintigraphy could have been repeated at a later time if the three-month results had been clinically significant or if postoperative edema had persisted for more than three months. Because neither of these conditions occurred, there was no need for further lymphoscintigraphy during our final follow-up at 12 months postoperatively.

Conclusions 

Our results showed that a nonsignificant reduction in postoperative lymphatic drainage was evident in comparison to the preoperative lymphoscintigraphic assessment. This reduction could be explained by the surgical trauma, even though the surgery caused no permanent injury of the lymphatic vessel. Another possible explanation of this temporary reduction in lymphatic drainage is the postoperative edema itself, which might have compressed the lymph vessels, thereby reducing their function. We can conclude, therefore, that liposuction on the medial and lateral surface of the lower limbs does not decrease lymphatic drainage, as shown by lymphoscintigraphic analysis three months postoperatively.