Platelet Rich Plasma
The third form of RIT is platelet rich plasma (PRP). This form of RIT is the one most widely used now by top athletes, and the one being researched in a number of universities and medical centers in various parts of the world. PRP is made from concentrated platelets derived from the patient's own blood. In this therapy a small sample of the patient's blood is drawn from their forearm and then spun at high speed in a centrifuge to separate out and concentrate the platelets. Platelets are one of the main cell lines in our blood, the other two being white and red blood cells manufactured in bone marrow. After injury, it is the platelets' function to form a clot to stop bleeding as well as to release certain growth factors that activate the healing mechanism of the body. Inside platelets are alpha granules, which contain cytokines, growth factors and bioactive proteins essential for tissue repair and healing. All of the chemical messengers contained within platelets appear to exert bioregulatory actions, which affect soft tissue and cartilage repair, inflammation, bone healing, wound healing and post-operative blood loss. PRP has also been shown to have antibacterial and antifungal properties. The platelets are often injected into areas where it is difficult for blood to naturally go thus promoting soft tissue and bone healing in these difficult to heal areas, i.e., the rotator cuff, tennis elbow, patella tendon, achilles tendon and plantar fascia, etc.
Dr. Allan Mishra and other researchers at Stanford University in Palo Alto, California have offered a commonly-accepted medical hypothesis for PRP's healing mechanism on tendon, muscle and ligament regeneration. They hypothesize PRP is delivered to the tissue in its inactivated form. The collagen in connective tissue activates the platelets, which then release their cytokines and growth factors. These chemical messengers signal genes to augment the healing stage and activate local stem cells. This causes stem cells to migrate from the local blood and bone marrow to the treatment site. The stem cells then become cartilage, ligament, tendon or muscle cells as needed at the injury site. At the same time, the cytokines and growth factors downgrade the local inflammation. They mitigate the internal war between the bad proteins, which slowly chew up the joint cartilage in severe osteoarthritis and the good proteins, which stops this degeneration. Without this help, in a typical knee with osteoarthritis it takes approximately five years from symptom onset to knee replacement, which becomes necessary when the cartilage is gone and the knee joint is bone on bone. The desired end result of PRP therapy is functional repair of an injured tendon, muscle or joint cartilage allowing it to bear greater mechanical stress during activity without pain.
Modern centrifuge-centered PRP was initially used over 20 years ago in the dental community to enhance wound healing in cancer patients who needed jaw reconstruction. The first report about PRP was published in January, 1987, in the International Journal of Artificial Organs by Dr. M. Ferrari and his associates following open heart surgery during which PRP was used to avoid excessive blood loss. Up to this point patients undergoing open-heart surgery would commonly need large transfusions of other donor's blood products to survive the surgery. At that time platelets were considered to function primarily as an aid to clotting. However, after Dr. Ferrari's work, it was shown that the post-op heart patients using PRP not only required fewer blood transfusions, they also healed quicker, required less pain medication and suffered significantly fewer infections.
There were other early studies on the successful use of PRP for the treatment of chronic non-healing skin ulcers. The patients in these studies had received standard wound care for an average of approximately four years. With the addition of platelet-derived growth factors, the mean time to 100% healing was decreased to a remarkable ten weeks. No abnormal cell growth or scar tissue was observed. There were other early studies that showed that PRP greatly improved the ability of skin grafts to hold and heal in burn patients.
Following these initial studies, the use of PRP expanded across many medical fields. PRP has been used in cardiovascular surgery, neurosurgery, ophthalmology, urology, ear, nose and throat surgery, and cosmetic surgery. It is now beginning to be used in sports medicine and orthopedic surgery. It is also being investigated for dry eyes, neurology, spinal disc and bone regeneration and for gastric ulcers.
A PRP injection contains two to 14 times the concentration of platelets found in normal blood and it appears that these platelets release protein and other particles that help the body to start a process of self-healing without triggering a clotting response. The procedure can be done in a doctor's office in thirty to sixty minutes and, as previously mentioned, some athletes have reported being back to their game as quickly as two days after the procedure, although three to ten days of downtime and six weeks away from rigorous training is more common.
PRP, platelet rich plasma, can be used in any situation where a doctor could use prolotherapy. PRP treatment generally costs about twice as much as prolotherapy because of the extra equipment and time needed to prepare the PRP solution. Most physicians who offer their patients both treatments reserve PRP for larger tendon and muscle tears, for severe ligament sprains, for any cartilage tear or defect and for more advanced arthritis of a joint. Also critical to treatment selection is the size of the area being treated. Most large spine treatments require multiple injections into several ligaments over the bony structures that cover the spine. The standard amount of solution needed to perform a spine treatment could be anywhere between 10-40 milliliters (mls) whereas the standard PRP solution obtained at one time is 7cc. Consequently if PRP is going to be used in the spine, its use will be injected into the most unstable spinal segment and the rest of the area can be treated with prolotherapy during the same treatment session.
Numerous physicians have been working with PRP to establish its effectiveness including Dr. Allan Mishra, a professor of orthopedics at Stanford University. Currently the Food and Drug Administration has approved PRP only for bone healing, not for soft tissue repair and even then most insurance companies may decline to cover it because they deem it "experimental". However, the consumer needs to understand all PRP and PRP treatments are not the same. Most PRP authorities agree PRP injection should be guided by ultrasound or x-ray to ensure accurate delivery of the medication. Whether the PRP should be used with an activator or buffering agent still needs to be worked out in clinical research trials. However, in either case it doesn't seem to cause harm or prolong recovery. Opinions vary about the optimal concentration of PRP. A body's normal platelet concentration is approximately 200,000 platelets per milliliter of blood. Researchers recommend a minimum four-to-five fold increase in platelet concentration for an improved healing affect. This is a minimal level where one type of tissue believed to be important in the healing cascade has been shown to regenerate in the literature. PRP preparations below this level do not influence the growth of this tissue any better than a control. Is the level of PRP concentration vitally important in healing outcomes? We don't know yet and anecdotally, doctors from a major university admitted PRP systems from those that make very concentrated PRP and those that don't both seem to work equally well in their athletic patient population. The bottom line is we still have a lot to learn about what type of PRP will emerge as the best one for treating various musculoskeletal conditions.