The Experimental Study Of The Bacteriology Of The Recipient Bed Of The Ruptured Expanded Flap And The Clinical Study Of The Ear Reconstruction About The Ruptured Postauricular Expanded Flap

Ear reconstruction is considered as one of the most complicated andchallenging technique in plastic surgery due to the histologic andanatomic properties of the ear. Successful ear reconstruction lies in twocrucial factors, the well sculptured framework and its overlying skin. Atpresent, autogenous rib cartilage is most favorable choice for frameworkmaterial, the "golden standard". The auricular framework of Medpor isthe beneficial supplement. However, whatever kind of framework isselected, the recipient bed must be germ free condition.As to the overlying skin, the skin in the mastoid area has goodtexture and color in harmony with the ear surface, therefore, it is the firstchoice for skin coverage during ear reconstruction. But the insufficientskin does also puzzles the plastic surgeons. The soft tissue expansionsolves part of the question and makes the reconstruction of the congenitaland acquired auricular deformities adjunct with tissue expansion as abetter technique.But the rupture of the expanded postauricular flap appears sometimes in clinic. When the expanded flap ruptured, the recipient bedbecame an open space. In that condition, whether the germ free conditionof the recipient bed changed, what it changed remain unknown at present.Because it is closely related to the success or failure of the operation, theknowledge is very important to the clinic. In addition, there is no study onwhich are the dangerous factors of the rupture of the postauricular flapand how to prevented and treated when it came at present. This study isaimed at investigating how to gain a perfect treatment plan when theexpanded postauricular flap ruptured by experimental and clinical studyin order to provide guidance to the plastic surgeons.The experimental study was mainly aimed at revealing whether thebacteria existed at the recipient bed, where they were, what they were andwhich antibiotics they were sensitive, and the relations between therupture time and the states mentioned above.So, we selected the New Zealand White rabbits as experimentalanimals. Firstly, 50ml expander was inserted in head of each of theanimals, and expanded regularly. After the expander were well expandedabout one month later, the 22 rabbits were made as ruptured expandedflap animal models according to same standard(the location and the sizeof the rupture) and were randomly classified into four groups (the othertwo were excluded from the experiment because one was deadunexpectedly and the other was excluded because of it's exposure of the filling port.), named as A group, B group, C group and D group.In group A, there were 5 animals and the rupture lasted one week. Ingroup B, there were 6 animals and the rupture lasted two weeks. In groupC, there were 6 animals and the rupture lasted three weeks. In group D,there were 5 animals and the rupture lasted four weeks.Then, the lengths of the skin-capsule composite tissue around therupture of each group were measured. When taking the rupture as thecenter, the tissues of the recipient bed were divided into six parts fromcenter to edge: the inflammatory reaction skin-capsule composite tissuearound the rupture, the ring-1 skin-capsule composite tissue, the ring-2skin-capsule composite tissue, the ring-3 skin-capsule composite tissue,the other left skin-capsule composite tissue and the capsular compositetissue of the floor of the recipient bed. The specimens were taken fromthese parts. The specimens included the specimens of the skin-capsulecomposite tissue and the scrapings of the of the surface of the capsule ofeach part with a swab of within the sterile operative field.All the specimens were quantificationally examined with Cooney'smethod and qualitatively examined for gram smear and aerobic andanaerobic cultures. All these examinations were under the supervision ofa senior microbiologist. After the specimens mentioned above weretaken, a small mass of the rabbit autogenous cartilage and Medpor wereimplanted into the recipient bed. At days 7 and 14 after the implantation, the specimens also were taken from the recipient bed. The specimensincluded the tissues from the floor of the bed and materials implanted.The tissues were examined according to the methods used above. Thematerials were examined by conventional light microscopy.The experiment results revealed that:①with the extension of therupture time, the length of the inflammatory reaction skin-capsulecomposite tissue gradually increased, the significant differences existedbetween each group(p＜0.05).②with the extension of the rupture time,the bacterial number in the recipient bed tissue increased.③when theexpanded flap ruptured, there would be two states at the floor of therecipient bed, infection or infection free. If the rupture time lasted morethan three weeks, the infectious ratio of the floor would increasesignificantly (17% vs 100%;P＜0.05). when the floor infection did exist,bacteria could be found in all parts of the tissues of the recipient bed. Ifthe floor didn't infect, the bacteria exist within the scope 0.Scm longerthan the inflammatory reaction skin-capsule composite tissues.④themain kind of bacteria was gram-positive bacteria. The bacteria wassensitive to the Vancomycin and Cidomycin.⑤the examine to therecipient bed at days 7 and 14 with the tissues of the recipient bed and thematerials implanted found no germ.In the clinical study, firstly, the factors that related to the rupture ofthe expanded postauricular flap, such as the common situation, the riskfactors, the course of the rupture, the treatments to the rupture, were summarized. Then, according to clinical facts and results of theexperiments, the rupture of the expanded postauricular flap was dividedinto four degrees, theⅠ-Ⅳ. At the same time, the principles of treatmentof auricular reconstruction were made according to the degree of therupture:①As to theⅠandⅡdegrees of the rupture, the principle was thatclosing the rupture as soon as possible, administering the sensitiveantibiotics via vein, removing the unhealthy tissues around the ruptureand reconstructing the ear with autogenous cartilage or Medporframework emergently.②As to theⅢdegree of the rupture, theprinciple was that closing the rupture as soon as possible, administeringthe sensitive antibiotics via vein, removing the unhealthy tissues aroundthe rupture radically and reconstructing the ear with autogenous cartilageor Medpor framework emergently when the redness and the swelling ofthe local tissues disappeared.③As to theⅣdegree of the rupture, theprinciple was that closing the rupture as soon as possible, administeringthe sensitive antibiotics via vein, removing expander and unfolding theexpanded flap, reconstructing the ear with autogenous cartilage orMedpor framework 3 months later or so.Based on the principles above, 67 patients of the congenital andacquired ear deformities with ruptured expanded postauricular flaps weretreated. As a result, in this series, the number of the patients withⅠandⅡdegree of rupture was 43. the number withⅢdegree of rupture was 17,the number withⅣdegree was 7. The number of the patients withautogenous cartilage auricular framework was 50. The number withMedpor auricular framework was 10. The number with expanded flapunfolded was 7. All the patients were left the hospital after the sutureremoved without any problems.Complications appeared in 4 cases. They were 2 cases of infectionappeared 20 and 30 days postoperation respectively, 1 case of hemotoma, incision decoherence and dissatisfied appearance of the reconstructed earrespectively. All the complication didn't affect the final results aftereffective treatments. The cases were followed up in this series, rangingfrom 3-40 months. The visible resorption and distortion of the cartilageauricular framework didn't happen. No Medpor auricular frameworkinfected. The shapes of the reconstructed ears were nature. Thearchitectures of the reconstructed ears were clear. There was noangulation deformity of the reconstructed ears. The size and location ofthe reconstructed ears was symmetry roughly.This study first took the rabbits as the experimental animals, thendeveloped the ruptured expanded flap animal models. Based on this, thebacteriology of the recipients bed of the ruptured expanded flap wasinvestigated. The investigation was a very important guidance todetermine the treatment plan of the ear reconstruction when the expandedpostauricular flap ruptured. The study results were put into the clinicpractice and developed a set of principles of treatments of the earreconstruction when the expanded postauricular flap ruptured. Accordingto the principles, good results were gained in clinic.