2
Medical and Surgical Applications of Autologous Blood Concentrates
The literature on PRP demonstrates the diversity of its clinical applications. Separate chapters in this text are devoted to clinical uses of PRP in plastic surgery and in oral, periodontal, and maxillofacial surgeries. Separate chapters are required because, for example in plastic surgery, there is a lengthy history of topical use of a variety of forms of platelet concentrates for skin wound healing, and there is a rapidly growing popularity of PRP use for esthetic and cosmetic purposes.1,2 There is a similarly lengthy history of various forms of PRP being used in a variety of periodontal and dentoalveolar procedures as well as in bone grafting, implant surgery, and reconstructive surgery.3,4
Since its first surgical application in the late 1980s for autologous transfusion support in open-heart procedures, PRP has been used in a variety of clinical settings because of its ability to enhance tissue repair and healing at wound sites.5 In April 2015, the National Center for Biotechnology Information listed more than 280 books, over 7,700 scientific and medical abstractions/citations, and more than 21,400 full-text journal articles on PRP, in a wide variety of fields, including cardiothoracic surgery, cosmetics, dentistry, maxillofacial surgery, neurosurgery, ophthalmology, orthopedics, otolaryngology, sports medicine, urology, and wound healing.
The application of PRP at wound sites is only natural because wound healing starts with the formation of a blood clot; the degranulation of platelets and the release of platelet growth factors regulate the wound healing process. The mechanisms of tissue repair that are aided by platelet-derived growth factors include cell migration and proliferation, the formation of new blood vessels from existing ones, extracellular matrix formation, and the remodeling of cells (Fig 2-1).
Over the last 30 years, the clinical use of PRP through various preparations and for a variety of therapies has grown in importance due mainly to the platelet growth factors released by PRP. These growth factor proteins exert tremendous influence on blood coagulation/clotting, immunities, angiogenesis, and wound healing. The concentration of platelets through cell sequestration to levels over 300 times their normal strength (with resultant concentrations in growth factors) allows clinicians to apply the concentrates to a number of wound healing therapies, including skin ulcers, oral and maxillofacial surgery and implantology, orthopedic surgery, burn treatment and the treatment of other wounds difficult to heal, soft tissue disease and injuries, and tissue engineering.6
This chapter focuses on the clinical application of PRP in the historically significant and wide-reaching medical areas of cardiothoracic surgery and orthopedics, respectively, as well as a number of miscellaneous clinical applications, including bone surgery, chronic wound healing, general surgery, neurosurgery, ophthalmology, otolaryngology, podiatry, and urology.
Cardiothoracic Surgery
Since the late 1980s, cardiac physicians have used cell-saving machines and platelet-rich plasmapheresis (allogeneic red blood cells and platelet concentrates) as methods to control nonsurgical bleeding after cardiopulmonary bypass (CPB) as well as postsurgical platelet dysfunction. Autologous blood components—including PRP, platelet-poor plasma (PPP), and red blood cell concentrate—are produced presurgically for postsurgical infusion to combat platelet dysfunction and bleeding.7 PRP has been used in cardiovascular surgery to maintain hemodynamic stability in patients following CPB.
FIG 2-1 Wound healing mechanisms of tissue repair that are enhanced by the application of PRP.
Box 2-1 Effects of platelet-rich plasmapheresis and PRP transfusion on cardiopulmonary bypass surgery outcomes8
• Reduces postoperative blood loss
• Reduces postoperative fresh frozen plasma transfusion
• Reduces postoperative red blood cell transfusion
• Reduces postoperative allogeneic red blood cell transfusion
A 2019 meta-analysis of randomized controlled clinical trials (RCTs) concluded that conducting platelet-rich plasmapheresis before CPB and transfusing PRP after reversal of heparin could reduce postoperative blood loss and hence the need for blood transfusions (Box 2-1).8 The study examined 15 RCTs with a total of 1,002 patients. Half of the patients (501) received PRP and the other half served a