We have been testing the use of platelet – rich plasma (PRP) in hair transplant surgery. Before discussing PRP, it is useful to take a look at the hair transplantation process in general.
Although we may sometimes take it for granted, it is quite amazing that hair follicles can be cut out of one area of the scalp and placed into an incision in another part of the scalp, and survive. Graft survival has been an interesting topic for many years. We can divide these factors into three main categories: 1) follicle trauma 2) biochemical factors and 3) vascular factors (oxygenation / revascularization).
Follicle trauma refers to the transection, dehydration, and crushing that follicles can be subjected to during the surgery. Use of microscopes and follicular unit techniques minimizes transection. Keeping grafts moist throughout the process, especially graft placement, helps eliminate dehydration. Careful graft placement by an experienced placer will reduce crushing and damage to the graft. Most surgeons agree that reducing follicle trauma is the most important factor in determining graft survival.
Biochemical factors refer to the stress the hair follicles experience when they are kept out of the body for a period of time and then returned to the oxygenated graft bed. When tissue is outside the body, it undergoes “storage injury” due to cut off of oxygenated blood, lack of nutrients, and temperature/pH shifts. When this tissue is then put back in the body, it is re-exposed to oxygen, which sets off a spark of free radical production that may effect graft survival (“ischemia-reperfusion injury”). In our hair transplant clinic, we use tissue holding solutions which contain buffers, nutrients, and antioxidants which have been shown to reduce storage and ischemia-reperfusion injury. Most doctors use normal saline which lack these ingredients.
Vascular factors include the immediate post-operative oxygenation and successful revascularization of each graft. Unlike organ transplants where the transplanted organ is hooked up to a new blood supply, hair transplants are “free” grafts which are surgically implanted without re-attaching a new blood supply (because that would be impossible to do with hair follicles). Until this process is complete, the graft must survive by passively absorbing oxygen from the surrounding tissue. We have been using and testing a variety of techniques to â€˜prime the pump’ so to speak: topical hyperbaric oxygen, vasodilators, and angiogenesis stimulators. This is where platelet – rich plasma (PRP) comes in.
PRP was developed in the 1970's but has only recently become popular in many fields of medicine. It is being widely used and studied in orthopedic surgery, dental/maxillofacial surgery, and regenerative medicine to name a few. Basically, platelets are isolated by first drawing the patient’s blood and spinning it down using special centrifuging techniques. A small fraction of plasma enriched with platelets is drawn from this and then reintroduced at the surgical site. Because the entire process is carried out with sterile, disposable instruments and devices, there is no chance for contamination.