Abstract】 Objective To investigate the clinical methods to improve the survival rate of fat free grafting. Methods Various methods were used to perform granulated fat free grafting in clinical practice, and the actual clinical results of each method were compared to find out the best operation method. Results The morphology of the recipient areas in the drug and control groups at 3 and 6 months after surgery and 72 hours after grafting were compared, and 70% and 60% of the original morphology was maintained; 40% and 30%, respectively. The average number of injections required was 2 , 4 , respectively. Conclusion Vascular dilation drugs and low negative pressure fat extraction and fat grafting with plasma can significantly improve the survival rate of fat grafting.
[Keywords] Granulated fat, free graft, survival rate
The clinical study for survival rate of free autogenous pellet fat graft LIU Wen-ge ,LIU Ling. Huangsi Aesthetic Surgery Hospital, Beijing 100011,China
[Abstract】 Objective To investigate a new technique to increase survival rate of free autogenous pellet fat graft. methods usie many methods to graft Results after 3 and 6 months ,the volume rate of treatment group and control group were 70%, 60%; 40% The number of fat injection were 2, 4 . Conclusion some drug and, low negative pressure and plasma can enhance the survival rate of free autogenous pellet fat graft.
[Key words】 Pellet fat; Free graft; Survival rate
Free fat autologous grafting is widely used in plastic surgery to repair various soft tissue depressions or defects in recent years because of its abundant tissue sources, easy operation, safety and reliability, repeatable injection, easy shaping, and especially because the procedure is less traumatic for the recipient and does not leave scarring [1]. However, how to improve the survival rate of fat grafting has been the key of the operation. In recent years, we have used various methods to perform fat grafting in 587 patients with body depressions, and the methods to improve the survival rate of their grafts are analyzed as follows.
Clinical data
From February 2000 to March 2007, a total of 587 cases of free granular fat autografting were performed, 26 males and 561 females, aged 16-76 years old, with an average of 42 years old. The surgical classification by grafting site was (individual patients had multiple sites filled at the same time):
1 Head: 16 cases of traumatic scalp depression.
2 Temporal filling 210 cases.
3 Face: 162 cases of nasolabial folds; 87 cases of subzygomatic folds; 84 cases of interbrow folds; 65 cases of subeyebag folds; 22 cases of traumatic forehead depression; 16 cases of upper lid depression due to excessive fat removal by blepharoplasty, 12 cases of orbital fat regression secondary to age-related aging or dysplasia; 32 cases of lower lid depression secondary to eyebag surgery; 2 cases of unilateral atrophy of the cheek due to trauma; 6 cases of congenital unilateral facial atrophy 8 cases; 8 cases of sunken cheeks caused by excessive liposuction; 4 cases of sunken jaws caused by excessive osteotomy of the mandibular angle; 22 cases of granular fat injection rhinoplasty; 32 cases of jaw augmentation; 8 cases of lip augmentation; 6 cases of lip bead augmentation; 2 cases of earlobe augmentation.
4 Trunk and extremities: 62 cases of filling the depression of upper buttocks; 12 cases of augmentation of pubic mound; 12 cases of augmentation of labia majora; 8 cases of penis enlargement; 18 cases of vaginal wall injection; 6 cases of breast injection; 3 cases of claw-shaped hand augmentation.
Methodology and results
I. Effect of drugs on the survival of granular fat grafting
The 196 patients were divided into drug group (161 cases) and blank control group (32 cases).
The drug regimen for the drug group was: intravenous antibiotics 1 day before and intraoperatively and postoperatively, generally 1-2 grams of cefadroxil, and 100-200 ML/day of of ofloxacin for those allergic to it. Intraoperatively and 5 days postoperatively intravenous vitamin C 2 g and chuanxiongzine 2-6 ml daily. from the 6th postoperative day, oral vitamin E-C combination and compound salvia tablets for one month. The addition of hormonal drugs and sodium bicarbonate to the expansion fluid injected into the donor area was prohibited, and the fat granules were cleaned with 160,000 units/500ML concentration of Gentamicin saline or 100ML of Ofloxacin/1000ML of saline. Basic fibroblast growth factor (bFGF) was added to the cleaned fat pellets.
Control group: only antibiotics were used, and the dosing method was the same as that of the drug group.
The cases selected in the two groups were as identical as possible in terms of the conditions of the donor-recipient area and the amount of fat injected. The changes in the morphology of the recipient area and the average number of repeat injections needed to reach the ideal condition at 3 and 6 months after surgery were observed as indicators of the difference in efficacy between the two.
Table 1 The effect of drug to granular fat autologous free graft (based on the volume of the recipient area at 72 hours postoperatively)
Tab 1 The effection of drug to the free autogenous pellet fat graft
Group Postoperative distant morphology of the recipient area as a percentage of the recipient area morphology at 72 hours postoperatively Number of injections
Drug group 70% (3 months) 60% (6 months) 2
Control group 40% (3 months) 30% (6 months) 4
Effect of fat particle collection method on graft viability
The results showed that, excluding the effect of the above mentioned drugs on grafting, the survival rate of grafting was higher with a thicker needle (4 mm diameter) than with a finer needle (2 mm diameter) for fat aspiration. The thicker the needle used to inject fat into the recipient area, the higher the survival rate, and a 2-mm diameter needle is preferable to a 12-gauge needle; a 7-gauge needle should be avoided.
The survival rate of the whole cut fat is higher than that of the fat collected by negative pressure aspiration, which is processed into small pieces of about 2 mm in diameter with sharp blades and ophthalmic shears and then injected into the graft. However, this method is only suitable for small doses of fat transplantation. In this case, we made a 1 cm incision at the umbilical fossa in 6 patients with lip augmentation, cut the fat block, processed it into appropriate fat globules according to the patient’s condition, and implanted it under the lip bead through an intraoral incision, with good postoperative survival without secondary injection.
In addition, the higher the negative pressure when suctioning and collecting fat from the donor area, the lower the survival rate. In this study, it was found that the fat grafting survival rate of 20 ml syringe was higher than that of 60 ml syringe due to low negative pressure.
The relationship between the cleaning method of fat particles and the survival rate
Fat grafting is particularly vulnerable to environmental contamination, and the higher the contamination rate, the higher the rate of liquefaction and necrosis after grafting. Therefore, the cleaning should be done in a closed syringe and mainly remove the upper layer of oil containing tissue composed of broken fat cells. Treatment of this layer is very simple, i.e., it is not moved into a smaller syringe before the final injection or the syringe is kept in a nearly vertical position, and then the last 0.5 ml of contents is not injected. Sometimes core aspiration can also be used to remove this oil-containing upper layer component. The plasma component of the collected adipose fluid is retained, and studies now show that this plasma component can act as a “soil” to facilitate the survival of adipocytes in the new environment of the recipient area. The survival rate of fat cell grafts containing a light red blood component was higher than that of fat grafts completely cleansed of the blood component down to pure golden fat particles in 421 patients. No fat washing or other preparation is usually required when using the swelling technique, and there is no evidence that washing the fat results in better assimilation of the graft. Only if the collected fat contains a significant amount of blood does it need to be gently cleaned with saline or Lingual fluid injected into the syringe containing the fat.
IV. Relationship between fat graft viability and donor-recipient area
1 The closer the distance between the donor and recipient areas, the higher the survival rate.
2 Under the same conditions, the richer the blood flow between the donor and recipient areas, the higher the survival rate of the graft. We have filled the temporal area and cheeks with fat from the scalp taken during wrinkle reduction and the absorption rate was very low.
3 In addition, the movement condition of the recipient area also affects the survival of fat, and the survival rate is low in areas with high or frequent activity. The survival rate of cheek grafting is lower than that of temporal area and scalp due to chewing or speaking activities. The breast area has a lower survival rate than the mons pubis due to the constant breathing movement of the thorax.
Other factors affecting the survival rate of fat grafting
Graft viability is also affected by age, the patient’s physical condition, postoperative dressing and fixation, and the nature of the depression or defect. Patients with high red blood cells or hemoglobin have a higher survival rate, while poor liver function or systemic diseases such as diabetes or kidney disease can reduce the survival rate. For example, in principle, breast implantation should not exceed 100ml at a time, and the ideal condition can be achieved by multiple injections with an interval of 2-3 months each time, and the injections should be done at multiple levels under the breast to avoid too many injections in one area and to increase the contact area between the fat and the normal tissue of the recipient area in order to improve the survival rate. It is difficult to implant free fat in scarred depressed areas.
Discussion
Neuber first reported performing autologous free fat grafting in 1893 and Bruning’s first fat injection method 20 years later when he placed small pieces of fat into a syringe for fat grafting to repair deformities after rhinoplasty [2]. Peer reported in 1950 that an average of 45% of free fat weight was lost about 1 year after filling [3]. Other reports have shown that surgically harvested fat is superior to that obtained by negative pressure suction in terms of volume maintenance. With the increasing sophistication of fat aspiration, Illou2 first described autologous grafting with large amounts of fat particles in the late 1970s [4]. In the 1930s to 1960s free fat grafting was widely used, and after the 1960s with the rise of anastomotic vascular greater omentum free grafting and the widespread use of silicone prosthesis and various artificial filling materials, fat grafting gradually decreased in clinical application due to more disadvantages. But in recent years, with the increase of complications of artificial materials and people’s excessive concern about their own health, free fat autografting is widely used in plastic surgery to repair various soft tissue depressions or defects due to abundant tissue sources, easy operation, safety and reliability, repeatable injection, easy shaping, especially the operation is less traumatic for the recipient and does not leave scarring. It is mainly used to repair subcutaneous depressed defects or deformities of the body. Most scholars believe that after fat free grafting, the fat cells are not viable, but the tissue cells of the host gradually grow into the graft site and obtain the fat released from the implanted fat cells after rupture to form new fat cells. 2. Partial cell viability theory In 1955, Peer proposed that fat free grafting After transplantation, a portion of the adipocytes close to the implant bed with blood movement can be viable, and blood circulation is established 4 days after transplantation. The smaller the trauma to the fat cells during surgery, the greater the percentage of viability. The isotopically labeled grafted adipocytes are visible 8 months after surgery and have the exact same morphology as normal adipocytes. The other part of the fat cells near the center of the transplanted block failed to establish blood flow in time. Aseptic necrosis occurred and free fat was released by rupture. One year later, it was observed that part of this free fat was carried away by the growing host tissue cells, while the other part became a fat cyst with an intact capsule wall and existed under the skin [5].
Fat grafting requires strict aseptic conditions and even minor infections can lead to fat necrosis and liquefaction, so the use of antimicrobials before and after the procedure, avoiding exposure of the collected fat to air and strict sealing are effective means to improve the survival rate of the graft. Another important survival condition for fat free grafting is that the implantation bed must be rich in blood flow. The survival rate of fat implantation in scarred areas is very low, so the use of blood-activating drugs such as Chuanxiongzin and compound salvia before and after surgery is effective in improving blood flow in the implantation bed. In the past, it was thought that transplanting free fat tissue at the suture after the main tendon or nerve suture could isolate the suture and surrounding tissues to prevent adhesions from occurring, but practice has shown that due to poor blood flow to the tendon or nerve of the implant bed, the fat cells are easily ruptured and liquefied, and the matrix is easily mechanized to form a scar, which instead easily causes adhesions [6].
References
1 Song Ruyao, Fang Changlin. Aesthetic plastic surgery. Beijing: Beijing Publishing House, 2002. 271-278.
2 Ira D. Papel, ed. and Cao Yilin, transl. Facial Plastic and Reconstructive Surgery. Jinan: Shandong Science and Technology Press, 2004.236-238.
3 Peer LA .Loss of weight and volume in human fat grafts.Plast Reconstr Surg 1995,5:217
4 Illouz YG.The fat cell “graft”: a new technique to fill depressions. Plast Reconstr Surg 1986,78:122-123.
5 McFarland JE. The free autogenous fat graft.
6 Walton R and Finesth F. Nereve grafting in the repair of complicated peripheral nerve trauma . J Trauma 1977,17:793.