What is Platelet Rich Plasma?
Platelet-rich plasma (PRP) is a practical application of tissue engineering. Although a formal definition was lacking (and many still use the term loosely) Dr Marx (the originator of the procedure) has recently revised the original definition. He now defines PRP as “the generation of 5ml of autologous plasma with a platelet count above 1 000 000/µl”.
How do we obtain PRP?
PRP must be harvested from the patient in whom it is to be used. There are essentially 2 processes that can be applied: The first is filtration, where the platelets are trapped in a filter system and then re-suspended. The second involves some form of differential centrifugation. There are a number of “PRP Kits” which are available for commercial use.
I personally use the differential centrifugation method. I draw blood in citrated glass tubes and then place these tubes in a table top centrifuge. I subject these tubes to a “soft spin” (1000g.min) to separate the plasma from the red cell mass. The plasma is removed and placed into another citrated glass tube and subjected to a “hard spin” (4600g.min) to obtain a platelet pellet and platelet poor plasma (PPP). The pellet is then re-suspended in a small volume of the PPP to obtain PRP.
In previous work which I presented at several scientific meetings, I have demonstrated that my PRP method’s platelet counts had a mean of 1 115 600/µl (range 906 000 – 1 463 000) and the mean relative concentration was 3.5 fold (range 3.31 – 3.72), which satisfies the present definition for PRP.
How does PRP work?
PRP works by amplifying the body’s normal and natural wound healing response mechanisms. This results in the deposition of new collagen and tightening of collagen. Platelets are the very first activators of this complex cascade of events – they are the “homing beacons” of the wound healing process. By concentrating the platelets and applying them to an area of tissue, the body will elicit a wound healing response. This response is proportionate to an injury in which the same amount of platelets would have been liberated.
What is PRP used for?
Because of the increased wound healing response, PRP is often used for chronic and slowly healing wounds. Areas such as diabetic foot ulcers, pressure ulcers and chronic venous ulcers are common uses. In areas where a more rapid healing response after injury is required, PRP is often used as an adjunct. Areas such as ligament tears and even early stage arthritis may be treated. The main use for plastic surgery is for aesthetic benefit. As the process ends with new collagen being laid down, it seems logical to use this for skin rejuvenation. The areas around the eyes, the face and the hands are excellent target areas for this, with improvement in fine lines and wrinkles. An effect on hair growth has also been demonstrated as it prolongs the growing phase of the hair.
How is the Procedure done?
The PRP is harvested as above and I mix in a modest volume of local anaesthesia. Using a 25G cannula (TSK Steri-glide is my preference) via a few tiny needle holes, the treatment area is flooded in the plane immediately below the skin in many passes. The entire procedure takes about 45 minutes to complete and is done under local anaesthesia only, as an outpatient. The procedure itself is minimally painful, but some tenderness due to the normal (and required) inflammatory process may be noted for several days after the procedure, in addition to swelling. Bruising does sometimes occur, but is usually self-limiting within 1-2 weeks.
How long does it take to see results?
Patient may be initially very pleased with the result, but this is because of the additional fluid volume and subsequent swelling. As this fades, the treated area may look like it is returning to normal, but only because the collagen has yet to be deposited. It takes at least 3 months before the results can be appreciated, but the results are gentle, natural and progressive, which make them appealing to many patients, who are seeking such results. Patients who want rapid and radical results will be disappointed and should consider other options, such as fillers.