This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Trauma, Subject name: Surgery
Negative pressure therapy is used in 
Select and explain. 
A. Bed sore in sacrum after debridment, B. After amputation, C. Chronic osteomyelitis wound, D. After split skin graft
A: Bed sore in sacrum after debridment
Answer: A: Bed sore in sacrum after debridment 
Explanation: Vaccum assisted closure Known as negative pressure wound closure Applying intermittent negative pressure of approximately - 125mmHg appears to hasten Debridement and the formation of granulation tissue in chronic wounds and ulcers A foam dressing is cut to size to fit the wound A perforated wound drain is placed over the foam and the wound is sealed with a transparent adhesive film. A vaccum is then applied to the drain. Negative pressure may act by decreasing oedema, by removing interstitial fluid and by increasing blood flow As a result bacterial counts decrease and cell proliferation increases thereby creating a suitable bed for graft or flap cover. Ref: Bailey and love 27th edition Pg no :30