Experimental Study Of The Vacuum Drainage In The Congested Flap On The Animal Models

Objective:In order to explore a simple and effective method to treatvenous congested flap and to provide new ideas and theoretical basis forfurther guidance of onclinical work, we expect to observe themicrocirculation changes of the congested flap after treatment of venouscongestion microcirculation Through the following methods.(1)observe themorphological changes of the flap by placing vacuum drainage in differentgroups and different location;(2)observe the congested flap's changes ofmicrocirculation and oxygen metabolism by placing vacuum drainage indifferent groups and different location;(3) compared the different effect ofmicrocirculation and oxygen metabolism between the method of vacuumdrainage and recanalization of veinMethods:1Experiment animals:40healthy and clean New Zealand long-eared rabbits,the male and the female half, body mass2.5~3kg.2The animal model formation: The belly hair of whites rabbits weredepilated by8%sodium sulfide three days before operation. The area is frombilateral inguinal upward to xiphoid levels, both sides of hair removal toaxillary line range. They were washed by warm water and dry naturally, thenthey were bandaged by the gauze and flexible net to prevent the abdominalskin injured by the cage. The rabbits were anesthetized with Xylazine andketamine which are mixed by the ratio of1:1by muscle injection inaccordance with0.2ml/kg, and there was another anesthetized everyhour(0.1ml/kg). The rabbits were lay down by supine position, fixed andsterilized by0.5%iodophor after successful anesthesia, formed an about12cm×4cm island flap under the lower abdomen taking the Shallow vein inabdominal wall as the pedicle. Then we deal with the vascular according to different group.3Experimental animals grouping: Each New Zealand long-eared rabbits dotwo lower abdominal skin flap, using random number allocation method, the80flaps divided into four groups, that is the control group, the proximaldrainage group,the distal drainage group and the recanalization of vein group.Each group has20flaps in which12for scanning and8for drawing materials.4Laser Doppler scanning: The rabbits' flaps were scanning by LaserDoppler scanning imager made by Denmark. In the group of scanning theflaps were scanned by laser Doppler respectively after2h,4h,8h,24h,3daysand7days.5Drawing materials from the flap: In the four groups there are32flaps wereformed for drawing materials at the time point of immediate postoperativeperiod,4h,8h,24h,3days,7days. We divided flap into upper,middle,below areas, and0.5×0.5cm skin were cut in various regions at the same timepoint.6Testing methods and observation index:6.1The specific area of flap was scanned by the laser Doppler scanningimager and the microcirculation blood flow data results of flap were recorded.6.2flap maleic dialdehyde(MDA) spectrophotometry test: First didhomogenate treatment to the tissue taken from flap, then got the supernatantsafter bathing and centrifuging. According the requirement of MDA kit, we didthe spectrophotometry test and calculated the MDA content.7Analysis of results: All the test data were expressed with mean±standarddeviation(X±S), dealed with by using SPSS13.0software, significanceanalysis by using the contrast statistics significance with the test P＜0.05.Results:1General observation results: Four hours after flap formed every groups'flap swelling, especially the control group which area is the most swelling;24hours later the groups flap swelling further increased, and flap of the controlgroup swollen more apparent,at the same time about1/3distal area of thecolor was dark purple, patchy dark brown crusts formed. Flaps of the proximal and the distal drainage group and the recanalizationof vein group were lighter swelling and less dark purple area than the controlgroup. The distal group's drainage fluid is about2ml, significantly more thanthe proximal drainage group.3days later the dark purple regional boundary was obvious in each group,and the dark purple regional of flap of the proximal and distal drainage groupwas less than the control group.7days later black crusts formed in the part ofthe distal part of the flap.2Laser Doppler image results:2.1Distal1/3region of flap4h,8h,24h,3d and7d after operation, thecomparisons of the flap microcirculation blood flow data results between theproximal drainage group,the distal drainage group,the recanalization of veingroup and the control group were statistically significant(P<0.05).24h afteroperation, the comparisons of the data results between the distal drainagegroup,the recanalization of vein group and the proximal drainage group wasstatistically significant(P<0.05).(Groups of multiple comparison s-n-kmethod).2.2Middle1/3region of flap4h,8h,24h,3d and7d after operation, thecomparisons of the flap microcirculation blood flow data results between theproximal drainage group,the distal drainage group,the recanalization of veingroup and the control group were statistically significant(P<0.05).3d afteroperation, the comparisons of the data results between the distal drainagegroup,the recanalization of vein group and the proximal drainage group wasstatistically significant(P<0.05).(Groups of multiple comparison s-n-kmethod).2.3Proximal1/3region of flap4h,8h,24h,3d and7d after operation, thecomparisons of the flap microcirculation blood flow data results between theproximal drainage group,the distal drainage group,the recanalization of veingroup and the control group were statistically significant(P<0.05).3d and7dafter operation, the comparisons of the data results between the proximaldrainage group,the recanalization of vein group and the distal drainage group were statistically significant(P<0.05).(Groups of multiple comparison s-n-kmethod).3MDA test results: We respectively measured the data results of MDAcontent in the distal middle and proximal areas, there was statistical significantbetween them (P<0.05). MDA content reached its peak in each group3dayslater. There was statistically significant between the recanalization of veingroup and the proximal drainage group,the distal drainage group (P<0.05).After3days there was no statistically significant between them(P>0,05).(Groups of multiple comparison s-n-k method).Conclusion:1The vacuum drainage can effectively reduce the swelling and congestionof the congested flap.2The obstacle of oxygen metabolism caused by the lack of oxygen mayoccur in the earlier period of the congested flap, the damage of the distal offlap will be hurted more obviously. Lack of oxygen in the flap ofrecanalization of vein may be caused by the secondary damage to the distalflap3Placing the vacuum drainage in the early period at the bottom of distal flapcan effectively improve the blood circulation of the distal.; placing thevacuum drainage under the pedicle of flap will active the blood circulation ofthe proximal, and do good to the healing of the flap. In the distal area of flap,there is no difference between the vacuum drainage and the recanalization, soit can effectively promote the healing the distal flap in the later period andimprove the survival rate of treatment to the congested flap.