Platelet Rich Plasma ("PRP")
Platelet rich plasma (PRP) is human blood that is spun down and separated producing a concentration of platelets above baseline values. Platelets are the clotting cells of our blood, but they also have shown great potential in enhancing muscle, tendon, and ligament healing. Studies suggest that growth factors released by platelets recruit reparative cells and may augment tissue repair and accelerate the rate of soft tissue healing.
Figure 1: Composition of blood
PRP has been used in surgery to augment shoulder rotator cuff and Achilles tendon repair. PRP has also shown great promise when injected into chronically injured tendons and muscles (e.g. forearm extensor tendons in tennis elbow) when proper healing has not taken place.
Many clinical trials are underway to determine the full spectrum of use for PRP. In a spine practice, clinicians have noted anecdotally promising results when PRP is injected into spinal ligaments or intra-articularly into facet joints and/or intervertebral discs when other traditional treatments have failed.
PRP is prepared by taking a sample of a patient’s own blood and placing it in a centrifuge to separate the red blood cells from white blood cells and platelets. With further concentration, plasma is divided into platelet-poor and platelet-rich portions. The platelet-rich portion is then collected and injected back into the injured tendon, ligament, muscle, joint, or disc that has been determined to be a source of pain and is not-healing appropriately. When structures around the spine are being injected, x-ray (i.e. fluoroscopy) guidance is usually employed to assure safe and proper placement of the PRP at the affected site. In the extremities, ultrasound-guidance is commonly used to inject PRP into the appropriate tendon, ligament or joint that is being targeted.
Figure 2: PRP Injection
Since PRP is derived entirely from a patient’s own blood, it is considered extremely safe without significant short or long-term adverse effects. Patients who receive injections of PRP may note temporary pain and soreness at the injection site, but this is usually short-lived. Prior to, and after injections, patients should refrain from using non-steroidal or steroidal anti-inflammatory medications as these drugs may impede the healing process. Continuing a well-designed course of physical therapy and avoidance of aggressive physical activity or overloading the injected tissues is advised in the weeks that follow the injections.
It has not been proven as to how long to wait after injections until positive results are seen or even how often injections need to be performed to see results. These are questions that will need to be answered in the literature moving forward. In general, PRP is not considered a first line treatment and is usually considered after other more traditional treatments have failed.
