1.The cause of incisional fat liquefaction
Incisional fat liquefaction mostly occurs in obese patients, and the mechanism is not clear. The reason may be related to the poor blood flow of the adipose tissue itself, and the surgery cut off the blood vessels crossed with the incision, so that its blood flow is even reduced. The nutrients needed in the healing process of the incision are partly provided by the diffusion of the skin layer and the anterior sheath layer. Once the nutrients provided by the blood transport and diffusion are not enough to meet the needs, the fat cells become necrotic and liquefied due to lack of nutrients, and aseptic inflammation occurs, which delays the healing of the incision.
Various mechanical stimuli, such as superficial burns of subcutaneous fat and degeneration of some fat cells due to high temperature generated by high-frequency electric knife, as well as rough operation, pulling hook and squeeze, incomplete hemostasis, ligation of large tissues, direct hemostasis by electric knife, and dehydration of tissues due to prolonged exposure of incision, all aggravate the obstruction of blood transport and oxidative decomposition of adipose tissue. This may be the main mechanism of fat liquefaction. The reason for the higher incidence of incisional liquefaction in obese patients is that the fat layer is too thick and the lack of nutrition is more obvious after the injury.
In order to expose well, it is inevitable to move the hook back and forth, sometimes pulling hard, which makes the tissue compression injury more serious. The tissue compression injury itself can lead to slow healing. In addition, patients with diabetes, hypertension and arteriosclerosis have poor peripheral circulation, poor tissue resistance and healing ability, which is also one of the reasons for incisional fat liquefaction.
2. Diagnosis of incisional fat liquefaction
Patients at high risk for the above-mentioned causes should be closely observed after surgery to detect and treat the incision as early as possible. Diagnosis conditions
(1) Formation of inflammation and edema in the incision 5-7 d after surgery;
(2) The patient has complaints of incisional pain of varying degrees, but the body temperature and local skin temperature are normal;
(3) No inflammatory reaction in the appearance of the incision, free sensation on subcutaneous palpation, and fluctuating sensation when fluid is formed in the middle and late stages;
(4) The incision is punctured or propped open and a yellowish, clear ooze containing fat droplets is seen;
(5) No signs of necrosis on the incision edge and subcutaneous tissue, but poor healing and free subcutaneous tissue; normal blood picture, large amount of fat droplets on microscopic examination of exudate, and no bacterial growth on 3 consecutive cultures.
3.Treatment of incisional fat liquefaction
Early treatment and adequate drainage are the key to treatment. The early or late treatment is closely related to the healing of the incision. Because the liquefied fat accumulation in the incision is not easily confined, it may spread to the surrounding adipose tissue to accelerate the liquefaction. After the small amount of liquefied fat is drained in the early stage, the cavity will be small and can be healed in one phase after pressure bandaging. If there is more exudate, some or all of the sutures should be removed decisively and drainage should be strengthened.
Unobstructed drainage can prevent the aggravation of fat liquefaction and promote the growth of granulation tissue. However, it is not advisable to let nature take its course and drain passively. We used hypertonic saline to clean the lumen and filled the drainage with hypertonic saline and Bevacor gauze. The healing period was shortened by 29.31% compared with the previous application of hypertonic saline drainage alone, which was a significant difference. Some patients with early detection of the incision were able to heal in one stage and were discharged on schedule.
The reason is that hypertonic saline can dehydrate local tissues and promote the early detachment of necrotic tissues; the composition of Beflex is topical recombinant bovine basic fibroblast growth factor, which has the effect of promoting the repair and regeneration of cells derived from mesoderm and ectoderm (such as epithelial cells, dermal cells, fibroblasts, vascular endothelial cells). Therefore, it has the effect of promoting capillary regeneration, accelerating the growth of granulation tissue and tissue repair. It can improve the local blood flow in the fat liquefaction area and accelerate the healing speed significantly compared with the previous report of 10-14d. And the scar reaction is light, which makes the incision more beautiful.
4.Prevention of incisional fat liquefaction
Prevention of incisional fat liquefaction should start from the perioperative period and surgical operation.
(1) Preoperative treatment of primary disease. Diabetic patients should control their blood sugar to below 10mmol/L, preferably below 8mmol/L. It is best to perform the surgery 1 to 2 weeks after the blood glucose is controlled to the ideal range, because although the blood glucose can be controlled in a short period of time, the tissue metabolism needs longer time to return to normal. Ambulatory monitoring of glycated hemoglobin can guide clinical treatment. For patients with hypertension and coronary artery disease, it is necessary to add drugs to improve microcirculation and increase tissue resistance while controlling blood pressure and correcting myocardial ischemia.
(2) Use the electric knife sparingly or correctly in the process of entering the abdomen. Damage to the dermis not only aggravates the scar reaction and affects the aesthetics of the incision, but more importantly, it destroys part of the exogenous nutrition pathway in the fat healing process, so the skin should not be cut with an electric knife. The fat layer should be cut in layers to avoid prolonged stay of the electric knife and repeated cutting. A small amount of bleeding should be stopped by compression, and active bleeding points should not be stopped directly by the electric knife, but only by clamping the bleeding point and indirect electrocoagulation. Avoid using violence and repeatedly moving the hook to minimize the pressure injury to the tissue.
(3) After suturing the anterior rectus abdominis sheath, the incision is wiped with gauze and rinsed with plenty of saline to remove as much necrotic fat as possible. The subcutaneous fascial layer and the lower 1/3 of the fat layer were tightly sutured without leaving a dead space. The remaining subcutaneous tissue is then sutured in full, and if there is bleeding, the bleeding is tightly stopped to avoid accumulation of blood under the skin.
(4) Suturing and knotting should be done gently to reduce fatty tissue cuts. Tie the knot loosely to the principle that the incision is close together, too loose subcutaneous fluid is easy to accumulate, too tight to affect the local blood flow.
(5) Immediately after surgery, use the palm of the hand to compress around the incision for 5 min to avoid subcutaneous blood leakage, which can reduce subcutaneous fluid accumulation. For high-risk incisions postoperative infrared radiation, close observation, timely treatment, so as not to delay the healing of the incision, causing unnecessary pain and economic burden to the patient. If the subcutaneous fatty tissue is too thick, it is estimated that there is a possibility of fat liquefaction, a rubber sheet should be placed under the skin to drain the necrotic material and exudate, and then removed after 24 to 48 hours.