Objective: To introduce the application of negative pressure aspiration method for the treatment of lymphedema of the extremities. Methods: Thirty-five cases of lymphedema of the extremities were treated by aspiration method, in which multiple small incisions were made in the swollen parts of the extremities, suction tubes were inserted, and the stagnant lymphatic fluid and hyperplastic adipose tissue were aspirated under negative 0.8-0.9 atmospheric pressure, with postoperative compression therapy. RESULTS: At 3-6 months of follow-up, the limbs were significantly reduced in size and softened in texture, and significant recent results were achieved. Conclusion: Negative pressure suction method for limb lymphedema with small incision and light trauma is a safe and effective treatment method for patients with non-severe fibrosis, and its immediate effect is obvious, while the long-term effect needs further observation. Limb lymphedema is divided into primary and secondary. Primary lymphedema is divided into early-onset and late-onset according to its early onset; secondary lymphedema is commonly seen after mastectomy, axillary lymph node dissection with radiation therapy, pelvic surgery, filarial infection and so on. Its pathogenesis is slow and persistent, and can be divided into three stages: lymphatic fluid accumulation, adipose tissue hyperplasia, and fibrosis [1]. Currently, there is a lack of effective treatment for lymphedema [1-4]. Non-surgical treatment includes bed rest, limb massage, elevation of the affected limb, compression therapy, as well as baking and microwave irradiation, which are effective in preventing the formation of lymphedema and treating mild lymphedema, while surgical treatment is required for severe lymphedema that has formed. Surgical methods include subcutaneous lymphatic fluid drainage implantation, superficial and deep fascial traffic surgery, lymphatic venous system anastomosis and surgical excision [1-8]. Lymphatic venous system anastomosis is divided into venous and lymphatic duct anastomosis, lymph node anastomosis, collecting lymphatic duct anastomosis and collecting lymphatic duct anastomosis depending on the surgical operation, but the long-term results are uncertain and there are many controversies. Surgical resection is often incomplete, requiring multiple operations, and there are many surgical complications such as lymphatic fistula, scar growth, infection, and skin breakdown. Recently, we applied the negative pressure suction method to treat lymphedema of the extremities with small incisions and light trauma, and achieved significant recent results with a follow-up of 3-6 months, and the relevant information is initially reported as follows. Data and methods 1: Clinical data Since February 1999, 35 cases of lymphedema of the extremities were treated by negative pressure suction method, including 16 cases of lymphedema of the upper extremities and 19 cases of lymphedema of the lower extremities. Among the upper limb lymphedema, there was 1 case of congenital lymphedema and 15 cases of postoperative breast cancer; among the lower limb lymphedema, there were 11 cases of congenital lymphedema and 8 cases of secondary lymphedema. 2: Surgical method The patients in this group did not undergo strict conservative treatment such as bed rest and elevation of the affected limbs 1-2 weeks before surgical treatment. The surgery was performed under general anesthesia without any injection of local anesthetics, saline and epinephrine before aspiration. The affected limb was elevated, a tourniquet was applied, and no blood expulsion was performed. Multiple small incisions, each approximately 0.5 cm in length, are made starting at the distal end of the limb and progressing from distal to proximal, with clear lymphatic fluid visible when the skin is cut. A suction tube is inserted and a negative pressure aspirator is turned on to remove the subcutaneous fat and the accumulated lymphatic fluid at a pressure of minus 0.8-0.9 atmospheres. Under the tourniquet, the aspirate consists of yellow fat particles and colorless lymphatic fluid, and the aspirate becomes bloody after releasing the tourniquet. Generally, 10-15 small incisions are required for unilateral upper limbs and 15-20 small incisions for unilateral lower limbs. The aspiration tubes are 2 mm, 2.5 mm and 3 mm in diameter with 1 or 2 lateral openings at the tip. The thin aspiration tubes are used for the dorsum of the fingers and the dorsum of the toes and the thick aspiration tubes are used for the upper forearm and the leg. The incision is not sutured to facilitate drainage, and the tourniquet is released after postoperative pressure bandaging with cotton pads and elastic bandages starting from the end of the limb. The affected limb is elevated postoperatively and antibiotics are applied perioperatively to prevent infection. The maximum aspiration volume was 3000 ml and the minimum was 350 ml. 2 cases of postoperative blood transfusion were performed with aspiration volumes exceeding 2500 ml. 3: Postoperative management Postoperative antibiotics and drugs such as ketamine were applied. On the first postoperative day, if there was more exudation, a new dressing was added to the original dressing. On the third postoperative day, the dressing was changed, the wound was examined, and the exudation had been significantly reduced, and the limb continued to be dressed with pressure. At this time, the limb had become significantly thinner, and after seeing the effect, the patient’s confidence in treatment was strengthened and it was easy to cooperate with further treatment. The antibiotics were stopped on the 5th postoperative day, and the elastic bandage was replaced with an elastic cuff, and the wound was discharged after about 10 days of basic healing, followed by outpatient visits. In six cases, during the application of the elastic bandage, the upper and lower extremities moved, causing the bandage to accumulate at the joint and obstructing venous return, causing swelling of the distal extremity, which was relieved after loosening the bandage. Conclusion The aspiration method was applied to treat 16 cases of upper limb lymphedema and 19 cases of lower limb lymphedema, including 1 case of primary upper limb, 15 cases of postoperative breast cancer, 11 cases of primary lower limb, 7 cases of post-inguinal lymphatic dissection, and 1 case of post filarial infection. The wound generally healed in about 10 days, with the longest being 18 days in one case of secondary lymphedema of the lower extremity. No lymphatic fistula or postoperative infection occurred in this group of patients. At a follow-up of 3-6 months, all achieved significant recent treatment results. The circumference of the affected limb decreased and approached that of a normal limb, with significant improvement in appearance, softening of texture, and relief of limb distension and pain (Figure 1), and there were no episodes of dermatitis during the follow-up period. one patient had acute upper limb lymphedema due to tumor dissemination and cancer thrombus formation after breast cancer surgery, and the upper limb swelled again one month after aspiration. Discussion The treatment of lymphedema is a difficult problem. At present, although lymphedema can be divided into obstructive and primary lymphedema according to the cause, the same treatment methods are still used clinically [1]. Massage and compression bandaging of the affected limb can prevent and treat mild lymphedema, and baking and microwave therapy are also used to treat mild lymphedema, but non-surgical treatment requires long-term persistence and cannot be curative, and most patients undergo repeated and multiple treatments and eventually still have swollen limbs with severe fibrosis and have to resort to surgical treatment. Finding a simple and effective surgical method is the common desire of both doctors and patients. It was recognized early that the clinical manifestation of lymphedema was only the accumulation of lymphatic fluid in the subcutaneous soft tissues and the proliferation of fat and fibrous tissue, not involving the deep fascia and the muscle tissue under it. As a result, attempts were made to create functional lymphatic communication by implanting drains under the skin and by communicating between the superficial and deep fascia in an attempt to drain the lymphatic fluid from the superficial fascia to the deep fascia and return it through the deep fascia. Due to the uncertainty of the effect, it has not been clinically promoted and is still reported sporadically. Although the mechanism of lymphedema confined to subcutaneous tissues only is not clear, the fact that lymphedema is confined within subcutaneous tissues constitutes an objective basis for the treatment of lymphedema by aspiration. With the development of microsurgical techniques, domestic and foreign people became enthusiastic about lymphatic venous system anastomosis for the treatment of lymphedema, which is considered to be a treatment method in accordance with the physiological condition [4, 6, 8], with venous and lymphatic vessels, collecting lymphatic vessels, collecting lymphatic vessels, lymph node anastomosis, etc. Its surgical operation is technically difficult, with good results in the near future and undetermined results in the long term. O’Brien et al [4], the founder of lymphatic venous anastomosis, reported 52 cases of lymphatic venous anastomosis with compression therapy, with no improvement in 30 cases at 3-year follow-up and an average 44% reduction in edema volume (596 ml) in the remaining 22 cases. Recently, O’Brien improved his method by performing partial resection followed by lymphatic vein anastomosis [5]. Lin Weilong et al [6] reported that after 9-15 years of follow-up with snapped set lymphatic vein anastomosis, 59.4% of patients had complete control of the dermatomal episode, 28.1% had occasional dermatomal episodes, and 12.5% were ineffective, while the limb circumference was only reduced by 0.5-2 cm. improvements in the anastomosis method are still being worked on to improve the quality of the anastomosis [8]. On the other hand, surgical excision for lymphedema has a long history of partial excision, subcutaneous debridement, limb autologous skin reimplantation, and free skin grafting, and the therapeutic effect depends on the thoroughness of the surgery and the size of the excision [3]. Miller et al [3] applied a fractionated wide excision method to completely remove the subcutaneous tissue from the ankle to the groin, with a mean follow-up of 14 years, and achieved satisfactory results. However, surgical excision is traumatic, complications such as lymphatic leakage, scar growth, and skin breakdown may occur, and the diseased tissue is difficult to be completely excised, requiring multiple operations. The aspiration method for lymphedema is one of the surgical resection methods, which has been proved by our clinical practice to be small incision, mild trauma, safe and effective, and can be repeated several times for patients with severe recurrence. The application of aspiration can remove the lymphatic fluid and hyperplastic adipose tissue accumulated in the subcutaneous tissue, effectively reduce the swelling of the limb and improve the appearance [1-2]. Since the lymphatic fluid accumulated under the skin is removed, the breeding ground for bacterial growth is removed, and the onset of dermatophytosis can be controlled after the procedure. Given that lymphedema is confined within the superficial subcutaneous fascia, Miller et al [3] recently suggested that the main component of lymphatic fluid production is located within the superficial fascia and that deep subfascial tissues such as muscle do not produce lymphatic fluid. Therefore, we believe that negative pressure suction removes most of the lymphatic fluid-producing tissues along with lymphatic fluid and hyperplastic adipose tissue, and the therapeutic effect depends on the thoroughness of subcutaneous tissue removal as much as the resection method. The developmental process of lymphedema [2] is first manifested by inadequate compensatory function or obstruction of lymphatic vessels, obstruction of lymphatic fluid return, stagnation in subcutaneous tissue, phagocytosis of lipid components within the lymphatic fluid by macrophages and adipocytes, hyperplasia of subcutaneous adipose tissue, and chronic swelling. Tissue swelling at this stage consists mainly of stagnant lymphatic fluid and hyperplastic adipose tissue. Later, the high protein content in the lymphatic fluid stimulates fibroblasts, which leads to active fibroblast proliferation, tissue fibrosis, rough and hardened skin, and “rubbery legs”. Because of the difference in treatment, Miller [3] referred to the former stage as lipedema to distinguish it from lymphedema in the general sense. The negative pressure aspiration method is suitable for the lipedema stage of lymphedema, and the recent effect on lymphedema limb reduction with obvious fibrosis is not ideal, whether the removal of stagnant lymphatic fluid through aspiration can improve the onset of dysentery and control or even alleviate limb fibrosis needs further study. Compression therapy plays a pivotal role in the treatment process [1-2, 5], and compression should be maintained by wearing an elastic sleeve and sock for a long time after surgery, tailored to the size of the limb whenever possible. Extensive peeling of the skin from the deep fascia, a relative excess of skin, and the appearance of wrinkles can be observed during surgery after aspiration, and the subcutaneous space is quickly filled with tissue fluid without the use of pressure bandages. Postoperatively, the limb was uniformly wrapped with pressure from the distal part of the limb, and within 2 weeks the limb was further reduced and could reach the same size circumference as the healthy side. Since our follow-up period was only 6 months at the longest, its long-term results need further observation. There were no serious complications in our group, one 14-year-old female with lower limb lymphedema reported numbness in the lower leg after surgery, which disappeared one week after surgery, and two patients with upper limb lymphedema complained of local pain after surgery, which disappeared within 2 weeks. brorson et al [1] reported 28 cases of upper limb lymphedema after breast cancer treatment by aspiration without complications, and the maximum aspiration volume reached 3850 ml. analysis of the reasons The reason is that the lymphatic fluid and adipose tissue accumulated under the skin were removed after aspiration, and with pressure dressing, the wound had already healed before a certain amount of lymphatic fluid had accumulated, so it was not easy to develop lymphatic fistula. In addition, because of the high pressure of lymphatic fluid in the body at the beginning, the surgery is an inside-out flow process, and as long as attention is paid to aseptic operation, infection is not likely to occur. The aspiration process should be performed with longitudinal suction, according to the anatomical position, to prevent damage to well-known superficial veins and dermal nerves. Frick [9] applied a cadaveric study to investigate the relationship between negative pressure aspiration methods and lymphatic tissue injury in the lower extremity, and pointed out that aspiration direction parallel to the longitudinal axis of the lower extremity can preserve most of the lymphatic vessel tissue and reduce lymphatic tissue injury; aspiration direction perpendicular to the longitudinal axis of the lower extremity has the greatest damage to lymphatic tissue. In his review of Frick’s paper, Mladick [10] clearly stated that he always kept the aspiration direction in line with the longitudinal axis of the limb in the treatment of lower limb lymphedema by aspiration. The treatment of lymphedema by aspiration inevitably destroys the original lymphatic vessels while removing lymphatic fluid and adipose tissue, and its long-term effects on lymphatic return are unclear and need to be further investigated.