Eficacy Of Dexamethasone And Hyperbaric Oxygen On Survival Of Dorsal Subdermal Vascular Network In Rats

Objective : This study was designed to determine if steroid or hyperbaric improved SVN(subdermal vascular network ) skin flap survival in rats ,and if steroid and hyperbaric oxygen (HBO) showed an additive beneficial effect. To help the surgery to use steroids or HBO and both of the two in their patients.Metheds :SVN skin flaps were made on the 40wister white rats dorsum. (1) The design of the groups: All the animals were divided into four groups randomly : group A is control group ,skin flap alone ,group B is flap plus DEX , group C is flap plus HBO , group D is flap plus HBO plus DEX. (2)The design of the svn: All animals were anesthetized with inject 5% sodium pentobarbital (10mg/kg) into the visceral cavity . Hair was clipped from the dorsum and the skin prepped with alcohol. Cranially based ,2.5×10 cm dorsal subdermal vascular network skin flaps were outline with methylene blue according to bony scapular landmarks . The flap was sharply incised and elevated between dartos and subdermal vascular network, then sutured to its bed . After the flaps were sutured in their original position , they were binding up with a certain depression and the proximal svn depression is higher than the distal end. (4)Animals received HBO (group B and group D) were subjected to two 90-minetes treatments of 100% O₂ at 2.4 atm per day for 9 consecutive days. The first treatment was begun within 8 hours after flap elevation . All the dexamethasone-treated animals (group B and group D) received intramuscular injection of dexamethasone(5mg/kg per injection 24 hours before flap elevation, and the seven days of postoperative time .Those animals not receive dexamethasone (group A and group C ) received intramuscular injection of an equal volume of saline solution placebo at the same dosage schedule .(4) On the 9th postoperative day ,we measured the surviving flap area and the new growth number of capvasculor and the height of meat tissue and the number of the infiltrated neutrophilic granulocyte in the svn.Results : The mean surviving flap area for group A was 10.9cm ,for group B it was 15.77> cm ,for group C it was .17.6n . cm . ,and for group D it was .17 cm . The approximately 20 % to 27 % improvement in surviving flap area was highly statistically significant (p < 0.01) when compared with controls . And there is statistically significant results between group C or D and B. However , no statistically significant difference was found between the two group C and D treatment modalities . All the dexamethasone-treated animals flap have less infiltrated neutrophilic granulocyte in the svn and than the animals without the dexamethasone-treat. The number of new growth capvascular in group B^ C and D is more than the control group rat. The height of meat tissue is as same as the the new growth number of capvascular in the four groups.Conclusion: These findings indicate that in a rat dorsal skin flap model, steroids or HBO improve skin flap viability, and steroids alone is not as efficacious as HBO or as steroids combined with HBO .We can choose one of the two to use to improve the more survival of the patients SVN skin flap.