Prevention of postoperative bleeding in anticoagulated patients undergoing oral surgery: use of platelet-rich plasma gel

The impact of submucosal PRP injection on wound healing after endoscopic sinus surgery: a randomized clinical trial

PURPOSE

Chronic rhinosinusitis (CRS) is a prevalent chronic disease observed on a global scale. The utilization of endoscopic sinus surgery (ESS) has gained significant recognition as an effective intervention for individuals with CRS and nasal polyps who have not responded to conventional treatments. The need (or not) for revision surgery frequently relies on the promotion of optimal wound healing. The impact of platelet-rich plasma (PRP) on tissue healing has been extensively examined in various surgical fields.

METHODS

The present prospective study involved 30 patients suffering with nasal polyposis who underwent endoscopic sinus surgery. 15 patients were assigned to the PRP group, and 15 patients to the control group. The clinical follow-up of the patients took place at specific intervals, at weeks 1, 2, 3, 4, 8, and 12 after the surgical procedure. The evaluator identified the existence of adhesions, crusting, bleeding, granulation and infection using a visual analogue scale score. The patients also completed the SNOT 22 questionnaire prior to surgery and at each postoperative visit.

RESULTS

The present study observed a lower incidence of adhesion, infection, hemorrhage and granulation in the PRP group. Furthermore, a statistically significant difference was detected between the groups.

CONCLUSION

Based on the findings of the present investigation, it seems that platelet-rich plasma (PRP) is beneficial on wound healing during the early stages following the surgical procedure. The technique is characterized by its limited invasiveness, which contributes to its low risk profile and the achievement of clinically good outcomes.

Is L-PRF an effective hemostatic agent in single tooth extractions? A cohort study on VKA and DOAC patients

OBJECTIVES

The aim of this clinical observational study was to assess the efficacy of L-PRF as a hemostatic agent in patients under treatment with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs).

MATERIALS AND METHODS

Patients under oral anticoagulant therapy (VKA or DOACs) who needed a single simple tooth extraction were enrolled. L-PRF plug was positioned inside the alveolus and secured with non-absorbable sutures. Surgical time, pain-VAS, paracetamol intake, intra-operative, post-operative biological complications, and bleeding events have been registered.

RESULTS

A total of 112 patients (59 patients for DOAC and 53 for VKA group) were enrolled. Post-operative bleeding was recorded in nine patients (17%) for VKA group and nine patients (15.3%) for DOACs group. None of the patients needed a medical support for managing of bleeding. Seven days after surgery, no cases of post-extractive complications occurred.

CONCLUSIONS

The use of L-PRF resulted in limited mild late post-operative bleedings without the need of medical intervention.

CLINICAL RELEVANCE

The use of L-PRF can be adopted for an uneventful post-operative curse in anticoagulated patients without chasing their therapy for single tooth extraction.

Perioperative Management of Antithrombotic Therapy: An American College of Chest Physicians Clinical Practice Guideline

BACKGROUND

The American College of Chest Physicians Clinical Practice Guideline on the Perioperative Management of Antithrombotic Therapy addresses 43 Patients-Interventions-Comparators-Outcomes (PICO) questions related to the perioperative management of patients who are receiving long-term oral anticoagulant or antiplatelet therapy and require an elective surgery/procedure. This guideline is separated into four broad categories, encompassing the management of patients who are receiving: (1) a vitamin K antagonist (VKA), mainly warfarin; (2) if receiving a VKA, the use of perioperative heparin bridging, typically with a low-molecular-weight heparin; (3) a direct oral anticoagulant (DOAC); and (4) an antiplatelet drug.

METHODS

Strong or conditional practice recommendations are generated based on high, moderate, low, and very low certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology for clinical practice guidelines.

RESULTS

A multidisciplinary panel generated 44 guideline recommendations for the perioperative management of VKAs, heparin bridging, DOACs, and antiplatelet drugs, of which two are strong recommendations: (1) against the use of heparin bridging in patients with atrial fibrillation; and (2) continuation of VKA therapy in patients having a pacemaker or internal cardiac defibrillator implantation. There are separate recommendations on the perioperative management of patients who are undergoing minor procedures, comprising dental, dermatologic, ophthalmologic, pacemaker/internal cardiac defibrillator implantation, and GI (endoscopic) procedures.

CONCLUSIONS

Substantial new evidence has emerged since the 2012 iteration of these guidelines, especially to inform best practices for the perioperative management of patients who are receiving a VKA and may require heparin bridging, for the perioperative management of patients who are receiving a DOAC, and for patients who are receiving one or more antiplatelet drugs. Despite this new knowledge, uncertainty remains as to best practices for the majority of perioperative management questions.

Is alteration in single drug anticoagulant/antiplatelet regimen necessary in patients who need minor oral surgery? A systematic review with meta-analysis

OBJECTIVE

This study aimed to systematically review literature about the effect of alteration of the pharmacological regimen in adult patients using anticoagulants or antiplatelets who need minor oral surgery.

MATERIAL AND METHODS

A search strategy was performed in three databases-PubMed-Medline, Scopus, and Embase-and included randomized clinical trials (either parallel or crossover), involving individuals under anticoagulant or antiplatelet therapy who underwent oral surgeries. Studies comprised two groups: those who stopped their medication prior to the dental procedure (control) or those who did not (test). Meta-analyses were conducted for the pooled risk ratio (RR) between the groups. Subgroup analyses were performed for anticoagulant and antiplatelet therapies.

RESULTS

Thirteen studies were included. It was found that patients who did not stop therapy had 157% higher intraoperative bleeding occurrences (95%CI: 1.40-4.71). In the subgroup analysis, warfarinazed patients showed significantly higher occurrences of intraoperative bleeding when compared with the control (RR: 1.79; 95%CI: 1.00-3.21). Conversely, there was no statistically significant difference in postoperative bleeding between the groups (RR: 0.81; 95%CI: 0.54-1.22; p = 0.42).

CONCLUSION

Minor oral surgeries can be safely performed in patients under antiplatelets or anticoagulants without drug regimen modification. Because these patients tend to bleed more during procedures, use of local hemostatic measures is strongly advised.

CLINICAL RELEVANCE

Management of patients under antiplatelet or anticoagulant drugs is still challenging in clinical practice. However, clinicians may perform minor oral surgeries safely without changing the pharmacological regimen. Use of local hemostatic measures is strongly advised during these procedures.

International normalized ratio (INR) values in patients receiving oral vitamin K antagonists and undergoing oral surgery: A clinical audit

INTRODUCTION

Dental extractions can be safely carried out on patients under vitamin K antagonists (VKAs) therapy, without stopping or changing the dosage, but the international normalized ratio (INR) needs to be monitored on the day of the intervention, showing adequate rates before proceeding.

OBJECTIVES

This study aims at evaluating INR values, measured before oral surgery procedures, to assess the rate of patients, under VKAs therapy, outside the therapeutic range.

MATERIALS AND METHODS

A clinical audit was carried out involving patients under VKAs, who needed minor oral surgery procedures, over a period of 18 months. The patient was instructed to not modify or suspend VKAs prior to the intervention. Before surgery, each patient fulfilled a questionnaire on dietary and oral hygiene habits, and a blood sample was collected for INR assessment (cut-off value for surgical procedure ≤3.5).

RESULTS

One hundred twenty-two patients were enrolled: 69 (56.6%) had an INR value within the established therapeutic range, 53 (43.4%) were out of range. No intra- or postsurgical major bleeding was recorded.

CONCLUSIONS

INR, measured on the same day of oral surgery, has the potential to prevent bleeding complications by the identification of those patients out of range, who may require adjusting the drug therapeutic dosage.

Mechanical and structural properties of leukocyte- and platelet-rich fibrin membranes: An in vitro study on the impact of anticoagulant therapy

OBJECTIVE AND BACKGROUND

Little is known about structural and mechanical properties of leukocyte- and platelet-rich fibrin (L-PRF) membranes and even less about the influence of antithrombotic drugs on L-PRF. The aim of this in vitro study is therefore to investigate mechanical properties, fibrin structure and cell content of L-PRF membranes and the impact of anticoagulant therapy on L-PRF.

METHODS

Blood samples were obtained from 12 volunteers and supplemented with either no, 1.25 IU, 2.5 IU, 5 IU, or 10 IU enoxaparin. L-PRF membranes were characterized with tensile testing, scanning electron microscopy, and measurement of platelets and leukocytes. Control and enoxaparin-supplemented L-PRF membranes were compared.

RESULTS

At 10 IU enoxaparin, no L-PRF membranes could be generated, whereas the low doses of 1.25 and 2.5 IU had no influence on L-PRF properties. The mechanical properties, fibrin networks, and number of platelets and leukocytes of 5 IU supplemented membranes were unlike the control membranes, but were not found to be significantly different because of limited sampling and inter- and intra-variability.

CONCLUSION

Low doses of the anticoagulant enoxaparin do not affect mechanical properties, fibrin network, nor cellular content of L-PRF, whereas high doses impair L-PRF generation.

Use of Platelet-Rich Plasma and Platelet-Rich Fibrin in Dentistry and Oral Surgery: Introduction and Review of the Literature

Platelet concentrates, mostly represented by platelet-rich plasma and platelet-rich fibrin, have gained significant interest in various medical and oral disciplines because of their potential to stimulate and boost regeneration of hard and soft tissues. Prepared from the patient’s own blood, they have been tested and used in various different surgical fields including oral and maxillofacial surgery. The effects of these biomaterials are described to be a result of the large concentration of platelets which contain a wide range of growth factors. The aim of this article is to introduce the principle and function of these platelet concentrates, to review their preparation, and to provide a comprehensive examination of the published oral and maxillofacial literature on this subject.

Anticoagulation Use prior to Common Dental Procedures: A Systematic Review

Currently, the number of patients on oral anticoagulation is increasing. There is a paucity of data regarding maintaining oral anticoagulation (especially novel oral anticoagulants) around the time of specific dental procedures. A dentist has three options: either to stop anticoagulation, to continue it, or to bridge with heparin. A systematic review of 10 clinical trials was conducted to address this issue. It was found that continuing anticoagulation during dental procedures did not increase the risk of bleeding in most trials. Although none of the studies reported a thromboembolic event after interruption of anticoagulation, the follow-up periods were short and inconsistent, and the heightened thromboembolic risk when stopping anticoagulation is well known in the literature. Heparin bridging was associated with an increased bleeding incidence. We recommend maintaining oral anticoagulation with vitamin K antagonists and novel oral anticoagulants for the vast majority of dental procedures along with the use of local hemostatic agents.

Advances in surgical applications of growth factors for wound healing

Growth factors have recently gained clinical importance for wound management. Application of recombinant growth factors has been shown to mimic cell migration, proliferation, and differentiation in vivo, allowing for external modulation of the healing process. Perioperative drug delivery systems can enhance the biological activity of these growth factors, which have a very short in vivo half-life after topical administration. Although the basic mechanisms of these growth factors are well understood, most have yet to demonstrate a significant impact in animal studies or small-sized clinical trials. In this review, we emphasized currently approved growth factor therapies, including a sustained release system for growth factors, emerging therapies, and future research possibilities combined with surgical procedures. Approaches seeking to understand wound healing at a systemic level are currently ongoing. However, further research and consideration in surgery will be needed to provide definitive confirmation of the efficacy of growth factor therapies for intractable wounds.

Non-Transfusional Hemocomponents: From Biology to the Clinic-A Literature Review

Non-transfusional hemocomponents for surgical use are autogenous products prepared through the centrifugation of a blood sample from a patient. Their potential beneficial outcomes include hard and soft tissue regeneration, local hemostasis, and the acceleration of wound healing. Therefore, they are suitable for application in different medical fields as therapeutic options and in surgical practices that require tissue regeneration.

Comparison between intra-articular platelet-rich plasma injection versus hydrocortisone with local anesthetic injections in temporomandibular disorders: A double-blind study

Introduction:

Temperomandibular joint (TMJ) is subjected to many disorders commonly called Temperomandibular disorders (TMDs); such as TMJ hypermobility, ankylosis, internal derangement, degenerative joint disease. Internal derangement is characterized by abnormal relationship of articular disc to the condyle and disc to fossa. In past many non-invasive conservative treatment modalities were tried out for its treatment which are joint unloading, use of anti-inflammatory agents, physiotherapy etc. Now a days corticosteroids and platelet rich plasma (PRP) has been proposed as an alternative therapeutic agent. We aimed to assess whether intra articular injection of PRP in TMJ minimises the symptoms of internal derangements as compared to injection of hydrocortisone with local anaesthetic.

Materials and Methods:

Twenty patients for a total of 32 joints with reducible anterior disc location were divided in two groups. One group received PRP injection and the other received hydrocortisone with local anaesthetic for arthroscopy in their affected joints. Both patients and operator were blinded to the contents of injections. The patients were assessed for pain, maximum inter-incisal mouth opening and TMJ sound.

Results:

In the group of PRP injection, pain was markedly reduced than the group of hydrocortisone with local anesthetic; mouth opening was increased similarly in both groups and TMJ sound was experienced lesser in patients who received PRP.

Conclusion:

Injections of PRP were more effective in reducing the symptoms, as compared to hydrocortisone with local anaesthetics.

Evaluating Effectiveness of Axiostat Hemostatic Material in achieving Hemostasis and Healing of Extraction Wounds in Patients on Oral Antiplatelet Drugs

AIM

The aim of this study was to evaluate the efficacy of Axiostat Hemostatic Dental dressing in achieving hemostasis postextraction and determining its effect on pain and healing of the extraction wound, compared with control, i.e., conventional method of extraction in patients on oral antiplatelet therapy.

MATERIALS AND METHODS

Totally, 40 patients on oral antiplatelet drugs were included in the study and overall 80 extractions were done applying split mouth study design, without altering patient's drug regime. Extraction sites were divided into two groups: Group I received Axiostat Hemostatic Dental Dressing (study site), and group II received conventional method; pressure pack with sterile gauze under biting pressure followed by suturing if required (control site) was used to attain hemostasis.

RESULTS

Extraction sites treated with Axiostat Hemostatic Dressing achieved hemostasis earlier (mean 1 minute 13 seconds) compared with control sites (mean = 14 minutes 1 second), which was also statistically significant (p < 0.001). Postoperative pain was considerably lower and significantly better healing was seen in the study group (p < 0.001) compared with the control.

CONCLUSION

Axiostat demonstrated to be an effective hemo-static agent that considerably lessens the bleeding time in patients on oral antiplatelet drugs postextraction. In addition, it even offered minimal postoperative pain and improved healing of the extraction wound. On comparing the results of this study with our study on HemCon Dental Dressing, Axiostat Dental Dressing (ADD) is found to be as effective and at par in achieving hemostasis in patients on oral antiplatelet therapy.

CLINICAL SIGNIFICANCE

The past few decades have seen an upsurge in use of low-dose aspirin either alone or in combination with other drugs. When these patients require dental/maxillofacial treatment, earlier concept of stopping these medications is associated with increased risk of thromboembolic event. The present study highlights an alternative approach using ADD which aids in quick hemostasis, accentuates healing, and reduce postoperative pain.

Concise Review: The Use of Adipose-Derived Stromal Vascular Fraction Cells and Platelet Rich Plasma in Regenerative Plastic Surgery

Tissue engineering has emerged at the intersection of numerous disciplines to meet a global clinical need for technologies to promote the regeneration of tissues. Recently, many authors have focused their attention on mesenchymal stem/stromal cells (MSCs) for their capacity to differentiate into many cell lineages. The most widely studied cell types are bone marrow mesenchymal stem cells and adipose-derived stem cells (ASCs), which display similar results. Biomaterials, cells, and growth factors are needed to design a regenerative plastic surgery approach in the treatment of organ and tissue defects, but not all tissues are created equal. The aim of this article is to describe the advances in tissue engineering through the use of ASCs, platelet rich plasma, and biomaterials to enable regeneration of damaged complex tissue. Stem Cells 2017;35:117-134.

Hemostasis and Post-operative Care of Oral Surgical Wounds by Hemcon Dental Dressing in Patients on Oral Anticoagulant Therapy: A Split Mouth Randomized Controlled Clinical Trial

INTRODUCTION

Hemostasis is a fundamental management issue post-operatively in minor oral surgical procedures. To ensure safety and therapeutic efficacy in patients, under oral anti coagulant therapy, is complicated by necessity for frequent determination of prothrombin time or international normalised ratio.

AIM

The aim of the study was to determine whether early hemostasis achieved by using Hemcon Dental Dressing (HDD) will affect post-operative care and surgical healing outcome in minor oral surgical procedures.

MATERIALS AND METHODS

A total of 30 patients, aged 18 years to 90 years, except those allergic to seafood, who consented to participate, were enrolled into this study. Patients were required to have two or more surgical sites so that they would have both surgical and control sites. All patients taking Oral Anticoagulation Therapy (OAT) were included for treatment in the study without altering the anticoagulant regimens. Institutional Review Board approval was obtained for the same. The collected data was subjected to statistical analysis using unpaired t-test.

RESULTS

All HDD surgically treated sites achieved hemostasis in 1.49 minutes and control wounds in 4.06 minutes (p < 0.001). Post-operative pain at HDD treated sites (1.87,1.27 on 1st and 3rd day respectively) was significantly lower than the control sites (4.0,1.87 on 1st and 3rd day respectively) p-value (0.001, 0.001 respectively). HDD treated oral surgery wounds achieved statistically significant improved healing both at 1st and 3rd post-operative days (p <0.0001).

CONCLUSION

The HDD has been proven to be a clinically effective hemostatic dressing material that significantly shortens bleeding time following minor oral surgical procedures under local anaesthesia, including those patients taking OAT. Patients receiving the HDD had improved surgical wound healing as compared to controls.

Dental extraction in patients receiving dual antiplatelet therapy

Background

Dual anti platelet therapy consists of administering antiplatelet (antiaggregant) drugs (clopidogrel and aspirin) to prevent thrombotic processes, as a preventative measure in patients with acute coronary disease, or in patients subjected to percutaneous coronary intervention.

Objectives

The purpose of this study was to evaluate the efficacy of a protocol for performing dental extraction in patients receiving dual anti platelet therapy.

Material and Methods

Thirty-two patients undergoing dental extractions were included in the study. The variables evaluated were: collagen-epinephrine fraction, collagen- adenosine diphosphate fraction, surgical surface, post-surgical measures, and adverse effects. Alveolar sutures and gauzes impregnated with an antifibrinolytic agent (tranexamic acid), which the patient pressed in place for 30 minutes, were applied to all patients as post-surgical measures. Descriptive statistics were calculated and analyzed with Student’s t-test to compare pairs of quantitative variables; simple regression analysis was performed using Pearson’s correlation coefficient. Statistical significance was set at p<0.05.

Results

Collagen/epinephrine fraction was 264.53±55.624 seconds with a range of 135 to 300 seconds, and collagen/ADP fraction was 119.41±44.216 seconds, both values being higher than normal. As a result of the post-surgical measures taken, no patients presented postoperative bleeding, hematoma or infection.

Conclusions

Dental extraction was safe for patients receiving dual anti-platelet therapy when using sutures and gauze impregnated with tranexamic acid, which the patient pressed in place for 30 minutes.

Key words: Aspirin, clopidogrel, tranexamic acid, dental extraction, platelet function.

Assessment of bleeding during minor oral surgical procedures and extraction in patients on anticoagulant therapy

Introduction:

The risk of postoperative hemorrhage from oral surgical procedures has been a concern in the treatment of patients who are receiving long-term anticoagulation therapy. A study undertaken in our institution to address questions about the amount and severity of bleeding associated with minor outpatient oral surgery procedures by assessing bleeding in patients who did not alter their anticoagulant regimen.

Subjects and Methods:

Eighty-three patients receiving long-term anticoagulant therapy visited Department of Oral and Maxillofacial Surgery from May 2010 to October 2011 for extractions and minor oral surgical procedures. Each patient was required to undergo preoperative assessment of prothrombin time (PT) and measurement of the international normalized ratio. Fifty-six patients with preoperative PT values within the therapeutic range 3–4 were included in the study. The patients’ age ranged between 30 and 75 years. Application of surgispon was done following the procedure. Extraction of teeth performed with minimal trauma to the surrounding tissues, the socket margins sutured, and sutures removed after 5 days.

Results:

There was no significant incidence of prolonged or excessive hemorrhage and wound infection and the healing process was normal.

Platelet-rich preparations to improve healing. Part II: platelet activation and enrichment, leukocyte inclusion, and other selection criteria

Multiple platelet-rich preparations have been reported to improve wound and bone healing, such as platelet-rich plasma (PRP) and platelet rich fibrin (PRF). The different methods employed during their preparation are important, as they influence the quality of the product applied to a wound or surgical site. Besides the general protocol for preparing the platelet-rich product (discussed in Part 1 of this review), multiple choices need to be considered during its preparation. For example, activation of the platelets is required for the release and enmeshment of growth factors, but the method of activation may influence the resulting matrix, growth factor availability, and healing. Additionally, some methods enrich leukocytes as well as platelets, but others are designed to be leukocyte-poor. Leukocytes have many important roles in healing and their inclusion in PRP results in increased platelet concentrations. Platelet and growth factor enrichment reported for the different types of platelet-rich preparations are also compared. Generally, TGF-β1 and PDGF levels were higher in preparations that contain leukocytes compared to leukocyte-poor PRP. However, platelet concentration may be the most reliable criterion for comparing different preparations. These and other criteria are described to help guide dental and medical professionals, in large and small practices, in selecting the best procedures for their patients. The healing benefits of platelet-rich preparations along with the low risk and availability of simple preparation procedures should encourage more clinicians to incorporate platelet-rich products in their practice to accelerate healing, reduce adverse events, and improve patient outcomes.

Anti-hemorrhagic agents in oral and dental practice: an update

Many oral surgeons in their daily practice have the problem of controlling postoperative bleeding. In surgical, oral and maxillofacial practice, standard anti-hemorrhagic protocols, especially in high risk patients, are obviously required and need to be continuously updated. The purpose of this review is to give a rational insight into the management of bleeding in oral and dental practice through modern drugs and medical devices such as lysine analogues and serine protease inhibitors, desmopressin, fibrin sealants, cyanoacrylates, gelatins, collagen and foams, protein concentrates, recombinant factors, complementary and alternative medicine and other compounds.

P.R.L. platelet rich lipotransfert: our experience and current state of art in the combined use of fat and PRP

The authors report their experience about the use of P.R.L. PLATELET RICH LIPOTRANSFERT method (platelet rich plasma mixed fat grafting) in 223 patients affected by soft tissue defects (ulcers, Romberg syndrome, Hemifacial atrophy, loss of substance, and signs of aging). This paper introduces the reader to PRP therapy and reviews the current literature on this emerging treatment modality, showing at the current clinical use of PRP in plastic and reconstructive surgery, with description of innovative methods and future prospects. This technique provides a promising alternative to surgery by promoting safe and natural healing. Here recent studies concerning the use of PRP in the treatment of chronic ulcers and soft tissue defect are reviewed.

Dental extraction in the thrombocytopenic patient is safe and complications are easily managed

PURPOSE

To characterize bleeding risk and management of bleeding in thrombocytopenic patients undergoing dental extraction.

MATERIALS AND METHODS

This retrospective cohort study included 68 patients with hematologic disease and concomitant thrombocytopenia undergoing dental extractions. The inclusion criterion was a platelet count of 100,000/μL or less at the time of consultation or extraction. Patients using anticoagulation therapy were excluded from the study. Predictors measured were age, gender, platelet count, platelet transfusion before or during surgery, local hemostatic measurements at the time of surgery (absorbable hemostat or antifibrinolytic rinse), number of teeth extracted, diagnosis, and extraction type. The primary outcome was postoperative bleeding requiring intervention. A secondary outcome was surgical site infection. Descriptive and bivariate statistics were computed and the P value was set at .05. No logistic regression was used based on the distribution of outcomes.

RESULTS

Sixty-eight patients underwent extraction of 200 teeth. Five (7.4%) had postoperative bleeding that was always controlled with routine intervention. Mean platelet count was 44,647/μL. Bleeding was more frequent with lower platelet levels (P = .048). Thirty-two patients received platelet transfusion and 26 received local measures. Platelet transfusion and local hemostatic measures had no effect on bleeding outcomes.

CONCLUSION

Surgical and routine extractions are safe procedures in patients with thrombocytopenia, and postoperative bleeding is typically well handled with simple local measures. The benefits of pre- or intraoperative platelet transfusion are unclear in this population. Likewise, the benefit of prophylactic local hemostatic measures is unclear and should be based on the surgeon's discretion and experience.

Growth-promoting action and growth factor release by different platelet derivatives

Abstract Platelet derivatives are commonly used in wound healing and tissue regeneration. Different procedures of platelet preparation may differentially affect growth factor release and cell growth. Preparation of platelet-rich fibrin (PRF) is accompanied by release of growth factors, including platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF) and transforming growth factor β1 (TGFβ1), and several cytokines. When compared with the standard procedure for platelet-rich plasma (PRP), PRF released 2-fold less PDGF, but >15-fold and >2-fold VEGF and TGFβ1, respectively. Also, the release of several cytokines (IL-4, IL-6, IL-8, IL-10, IFNγ, MIP-1α, MIP-1β and TNFα) was significantly increased in PRF-conditioned medium (CM), compared to PRP-CM. Incubation of both human skin fibroblasts and human umbilical vein endothelial cells (HUVECs) with PRF-derived membrane (mPRF) or with PRF-CM enhanced cell proliferation by >2-fold (p<0.05). Interestingly, PRP elicited fibroblast growth at a higher extent compared to PRF. At variance, PRF effect on HUVEC growth was significantly greater than that of PRP, consistent with a higher concentration of VEGF in the PRF-CM. Thus, the procedure of PRP preparation leads to a larger release of PDGF, as a possible result of platelet degranulation, while PRF enhances the release of proangiogenic factors.

Effectiveness of Hemcon Dental Dressing versus Conventional Method of Haemostasis in 40 Patients on Oral Antiplatelet Drugs

OBJECTIVES

The purpose of the study was to evaluate the effectiveness of the HemCon Dental Dressing (HDD) in controlling post extraction bleeding and to ascertain its role in healing of extraction wounds, as compared to control.

METHODS

The 40 participants in the study were all receiving oral antiplatelet therapy (OAT). A total of 80 extractions were conducted without altering the patients' drug therapy. The extraction sites were divided into 2 groups: one group received a HDD, and the control group where the conventional method of pressure pack with sterile gauze under biting pressure (followed by suturing if required) was used to achieve haemostasis.

RESULTS

All HemCon treated sites achieved haemostasis sooner (mean = 53 seconds) than the control sites (mean = 918 seconds) which was statistically significant (P <0.001). Postoperative pain in the HDD group (1.74) was also significantly lower than in the control group (5.26) (P <0.001). Approximately 72.5% of HDD-treated sites showed significantly better postoperative healing when compared to the control site (P <0.001).

CONCLUSION

HDD proved to be an excellent haemostatic agent that significantly shortened the bleeding time following dental extraction in patients on OAT. Additionally, HDD offered significantly improved post-operative healing of the extraction socket and less postoperative pain.

Oral surgery for patients on anticoagulant therapy: current thoughts on patient management

Minor oral surgical procedures make up a significant part of the daily practice of dentistry. With the increased sophistication of medical technology and medications there is increased likelihood of performing surgery on patients who are being treated for conditions that require some type of anticoagulant therapy. These patients are at an increased risk for perioperative bleeding or thrombotic complications if anticoagulation is discontinued or the dosage is adjusted. Therefore, a fine balance needs to be obtained and adequate preparation of these patients is the key to establishing this balance. This article reviews suggested approaches to the management of such patients.

BLOOD-DERIVED, TISSUE ENGINEERING BIOMATERIALS

Fibrin sealant and platelet gels are human blood-derived, biodegradable, non toxic, surgical products obtained by mixing a fibrinogen concentrate or a platelet rich plasma with thrombin, respectively. Fibrin sealant is now a well known surgical tool increasingly used to stop or control bleeding, or to provide air and fluid tightness in many surgical situations. Platelet gels are newly developed preparations that are of specific interest because they contain numerous physiological growth factors and cytikines that are released upon the activation of blood platelets by thrombin. These growth factors, including PDGF, TGF-β 1, BMP, and VEGF have been shown to stimulate cell growth and differentiation with special clinical benefits for soft and bony tissue healing and regeneration. Platelet gels allow surgeons to manipulate the cellular environment of surgical sites and to guide tissue regeneration. A specific interest of such products is observed for the induction of osteogenesis and chondrogenesis. Advances in the preparation, clinical use, and safety of these two important classes of blood-derived biomaterials are reviewed.

Perioperative management of antithrombotic therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

This guideline addresses the management of patients who are receiving anticoagulant or antiplatelet therapy and require an elective surgery or procedure.

METHODS

The methods herein follow those discussed in the Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines article of this supplement.

RESULTS

In patients requiring vitamin K antagonist (VKA) interruption before surgery, we recommend stopping VKAs 5 days before surgery instead of a shorter time before surgery (Grade 1B). In patients with a mechanical heart valve, atrial fibrillation, or VTE at high risk for thromboembolism, we suggest bridging anticoagulation instead of no bridging during VKA interruption (Grade 2C); in patients at low risk, we suggest no bridging instead of bridging (Grade 2C). In patients who require a dental procedure, we suggest continuing VKAs with an oral prohemostatic agent or stopping VKAs 2 to 3 days before the procedure instead of alternative strategies (Grade 2C). In moderate- to high-risk patients who are receiving acetylsalicylic acid (ASA) and require noncardiac surgery, we suggest continuing ASA around the time of surgery instead of stopping ASA 7 to 10 days before surgery (Grade 2C). In patients with a coronary stent who require surgery, we recommend deferring surgery > 6 weeks after bare-metal stent placement and > 6 months after drug-eluting stent placement instead of undertaking surgery within these time periods (Grade 1C); in patients requiring surgery within 6 weeks of bare-metal stent placement or within 6 months of drug-eluting stent placement, we suggest continuing antiplatelet therapy perioperatively instead of stopping therapy 7 to 10 days before surgery (Grade 2C).

CONCLUSIONS

Perioperative antithrombotic management is based on risk assessment for thromboembolism and bleeding, and recommended approaches aim to simplify patient management and minimize adverse clinical outcomes.

The Effect of Platelet-rich Plasma on Wounds of OLETF Rats Using Expression of Matrix Metalloproteinase-2 and -9 mRNA

Background

Complicated diabetic patients show impaired, delayed wound healing caused by multiple factors. A study on wound healing showed that platelet-rich plasma (PRP) was effective in normal tissue regeneration. Nonetheless, there is no evidence that when plateletrich plasma is applied to diabetic wounds, it normalizes the diabetic wound healing process. In this study, we have analyzed matrix metalloproteinase (MMP)-2, MMP-9 expression to investigate the effect of PRP on diabetic wounds.

Methods

Twenty-four-week-old male Otsuka Long-Evans Tokushima Fatty rats were provided by the Tokushima Research Institute. At 50 weeks, wounds were arranged in two sites on the lateral paraspinal areas. Each wound was treated with PRP gel and physiologic saline gauze. To determine the expression of MMP-2, MMP-9, which was chosen as a marker of wound healing, reverse transcription polymerase chain reaction (RT-PCR) was performed and local distribution and expression of MMP-2, MMP-9 was also observed throughout the immunohistochemical staining.

Results

RT-PCR and the immunohistochemical study showed that the levels of MMP-2, MMP-9 mRNA expression in PRP applied tissues were higher than MMP-2, MMP-9 mRNA expression in saline-applied tissues. MMP-9 mRNA expression in wounds of diabetic rats decreased after healing began to occur. But no statistical differences were detected on the basis of body weight or fasting blood glucose levels.

Conclusions

This study could indicate the extracellular matrix-regulating effect observed with PRP. Our results of the acceleration of wound healing events by PRP under hyperglycemic conditions might be a useful clue for future clinical treatment for diabetic wounds.

Successful management of bleeding after dental procedures with application of blood stopper: a single center prospective trial

AIM

Ankaferd Blood Stopper (ABS), as an herbal complementary medicine, has been approved for the management of clinical hemorrhages in Turkey, including dental interventions. Basic, preclinical and clinical studies disclosed the settings of the topical hemostatic use of ABS. The aim of this study is therefore to assess the efficacy and safety of ABS as an antihemorrhagic agent in the bleedings associated with dental procedures in patients with normal and impaired hemostasis.

MATERIALS AND METHODS

ABS has been topically applied by homogeneously spraying to the 113 patients during dental interventions within its on-label indications. A median of 0.5 ml (IQR:0.5-1 ml) ABS was administered after tooth extraction with prolonged hemorrhages.

RESULTS

After the administration, bleeding stopped in less than 10 seconds in 59 (52.2%) patients, and below 22.5 seconds (IQR: 18, 8-30) in 54 patients (47.8%). A total of 141 procedures were performed in these 113 patients, and nearly 72.5 ml ABS was used with a total cost of 98 €.

CONCLUSION

ABS as a new herbal medicine was found to be an effective method for controlling bleeding related to dental procedures. No patient had wound infection and the healing process appeared to be normal. Topical ABS could be useful for the local hemostasis and wound healing in periodontal surgeries.

CLINICAL SIGNIFICANCE

In this prospective study ABS, for the first time, has demonstrated its potential for being an effective hemostatic agent for the management of bleedings due to dental procedures.

Prevention of hemorrhagic complications after dental extractions into open heart surgery patients under anticoagulant therapy: the use of leukocyte- and platelet-rich fibrin

Leukocyte- and platelet-rich fibrin (L-PRF) is a biomaterial commonly used in periodontology and implant dentistry to improve healing and tissue regeneration, particularly as filling material in alveolar sockets to regenerate bone for optimal dental implant placement. The objective of this work was to evaluate the use of L-PRF as a safe filling and hemostatic material after dental extractions (or avulsions) for the prevention of hemorrhagic complications in heart surgery patients without modification of the anticoagulant oral therapy. Fifty heart surgery patients under oral anticoagulant therapy who needed dental extractions were selected for the study. Patients were treated with L-PRF clots placed into 168 postextraction sockets without modification of anticoagulant therapy (mean international normalized ratio  =  3.16 ± 0.39). Only 2 patients reported hemorrhagic complications (4%), all of which resolved a few hours after the surgery by compression and hemostatic topical agents. Ten patients (20%) showed mild bleeding, which spontaneously resolved or was resolved by minimal compression less than 2 hours after surgery. No case of delayed bleeding was reported. The remaining 38 patients (76%) showed an adequate hemostasis after the dental extractions. In all cases, no alveolitis or painful events were reported, soft tissue healing was quick, and wound closure was always complete at the time of suture removal one week after surgery. The proposed protocol is a reliable therapeutic option to avoid significant bleeding after dental extractions without the suspension of the continuous oral anticoagulant therapy in heart surgery patients. Other applications of the hemostatic and healing properties of L-PRF should be investigated in oral implantology.

Is autologous platelet concentrate beneficial for post-extraction socket healing? A systematic review

The aim of this systematic review was to assess if the use of autologous platelet concentrates may be beneficial to the healing of extraction sockets. Medline, Embase and Cochrane Central Register of Controlled Trials were searched using a combination of specific search terms. Hand searching of the relevant journals and of the bibliographies of reviews was also performed. Prospective comparative studies evaluating the effect of a platelet concentrate on fresh extraction sockets were included. Outcome variables related to hard and soft tissue healing, aesthetics and postoperative discomfort were considered. A methodological study quality assessment was made. The initial search yielded 425 articles, eight were finally included. 207 tooth extractions (104 tests and 103 controls) in 115 patients were evaluated. The articles provided a broad range of variable outcomes to assess the regenerative potential of platelet concentrate and its possible benefits to the treatment. Favourable effects on hard and soft tissue healing and postoperative discomfort reduction were often reported. A large heterogeneity was found regarding study design, sample size, surgical techniques and methods for preparing platelet concentrates. Standardization of experimental design is needed in order to detect the true effect of platelet concentrates in regenerative procedures of extraction sockets.

Peri-operative management of ophthalmic patients taking antithrombotic therapy

Increasing number of patients presenting for ophthalmic surgery are using oral anti-coagulant and anti-platelet therapy. The current practice of discontinuing these drugs preoperatively because of a presumed increased risk of bleeding may not be evidence-based and could pose a significant risk to the patient's health. To provide an evidence-based review on the peri-operative management of ophthalmic patients who are taking anti-thrombotic therapy. In addition, we briefly discuss the underlying conditions that necessitate the use of these drugs as well as management of the operative field in anti-coagulated patients. A semi-systematic review of literature was performed. The databases searched included MEDLINE, EMBASE, database of abstracts of reviews of effects (DARE), Cochrane controlled trial register and Cochrane systematic reviews. In addition, the bibliographies of the included papers were also scanned for evidence. The published data suggests that aspirin did not appear to increase the risk of serious postoperative bleeding in any type of ophthalmic surgery. Topical, sub-tenon, peri-bulbar and retrobulbar anaesthesia appear to be safe in patients on anti-thrombotic (warfarin and aspirin) therapy. Warfarin does not increase the risk of significant bleeding in most types of ophthalmic surgery when the INR was within the therapeutic range. Current evidence supports the continued use of aspirin and with some exceptions, warfarin in the peri-operative period. The risk of thrombosis-related complications on disruption of anticoagulation may be higher than the risk of significant bleeding by continuing its use for most types of ophthalmic surgery.

Autologous platelet-derived growth factors (platelet-rich plasma) as an adjunct to mucosal advancement flap in high cryptoglandular perianal fistulae: a pilot study

AIM

The aim of this study was to explore autologous platelet-rich plasma as an adjunct to the staged mucosal advancement flap in the treatment of perianal fistulae.

METHOD

Between February 2006 and May 2007, 10 patients with fistula tracts transversing from the middle-third or upper part of the anal sphincter were treated for at least 3 months with noncutting setons prior to definitive closure by autologous platelet-rich plasma as an adjunct to a mucosal advancement flap. Five patients smoked tobacco.

RESULTS

The study group consisted of six women and four men with a median age of 44 (range 30-75) years and a median follow up of 26 (range 17-32) months. One (10%) patient had a recurrent fistula. No new continence disorders developed after definitive treatment in both groups.

CONCLUSION

Platelet-rich plasma as an adjunct to a staged mucosal advancement flap for the treatment of perianal cryptoglandular fistulae is a promising treatment modality and seems to establish a high healing rate.

The dental patient on oral anticoagulant medication: a literature review

Specific diseases and medications may considerably influence the delivery of oral care and the course of dental therapy. The purpose of this literature review is to examine the relationship between oral anticoagulant medication and dental treatment. Electronic and manual searches were conducted for clinical studies in the English literature for the years 1988-2010. The review process provided a total of 110 pertinent literature references, out of which 38 studies dealt with oral anticoagulants and dental treatment. Different treatment strategies relative to dental periprocedural anticoagulation regimens have been identified, and their accompanying thromboembolic and bleeding risks are being presented and discussed. Regarding to what extent a safe and successful dental treatment in patients on anticoagulant medication is feasible, the level of evidence is lacking. Until high-level data are provided, an individualised treatment approach after consultation with the physician of the patient is highly recommended.

Application of platelet-rich plasma in maxillofacial surgery: clinical evaluation

The authors report their experience on 15 cases, including reconstructive surgery of the jaws, postextraction alveolar bone regeneration, and oral implantology. The aim of the study was to evaluate the different effects on jaws' bone regeneration with or without the use of local application of platelet-rich plasma (PRP). The results we report showed the efficacy of the PRP treatment: postoperative patients' satisfaction and low-morbidity course confirmed the quality of the results. The article will help the reader to (1) understand the PRP preparation, (2) find local applications in oral and maxillofacial surgery, and (3) evaluate the general effect of PRP.

Platelet-rich plasma diminishes calvarial bone repair associated with alterations in collagen matrix composition and elevated CD34+ cell prevalence

The interaction between platelets and both type I and III collagens plays an important role in modulating platelet adhesion and aggregation, also contributing to the chemotaxis of CD34+ cells. The interaction with type III collagen can maintain high levels of collagen and alter the biology of bone repair when the PRP is used. The aim of this study was to evaluate the effect of platelet-rich plasma (PRP) and autograft on the presence of type III and type I collagens, the ratio between them, as well as the presence of CD34+ progenitor cells, while comparing these results by means of a histomorphometric analysis of the bone tissue. Four bone defects (8.0mm in diameter and 2.0mm in depth) were produced on the calvarium of 23 rabbits. The surgical defects were treated with either autogenous bone grafts, autogenous bone grafts with PRP and PRP alone. Animals were euthanized at 2, 4 or 6 weeks post-surgery. Histological, histomorphometric and immunohistochemical analyses were performed to assess repair time, as well as the expression of type I and III collagens, and number of progenitor CD34+ cells. Data were analyzed using the ANOVA and Student-Newman-Keuls test (alpha=5%). An enlarged granulation and medullary tissue areas in the PRP groups were observed. The use of PRP in this study hindered bone deposition, also enhanced type III to type I collagen ratio and the chemotaxis of CD34+ progenitor cells, similarly to a thrombogenic effect.

Application of platelet-rich plasma in plastic surgery: clinical and in vitro evaluation

The clinical use of platelet-rich plasma (PRP) for a wide variety of application has been reportedly employed most prevalently in problematic wounds, maxillofacial and hemi-facial atrophy, Romberg Syndrome, and diabetic foot ulcers. To our knowledge, PRP has never been described in the enhancement of fat grafting during tissue-engineering application in vivo. The authors describe the preparation of PRP and its use in a series of 43 patients who underwent plastic, reconstructive, and maxillofacial surgery for chronic lower extremity ulcers (n = 18) and multiple facial applications (n = 25). PRP mixed with fat grafting was used in 76% patients affected by multiple facial diseases and in 88.9% patients affected by lower extremity ulcers. PRP injection alone was used in the remaining patients. The authors observed that after a 7.1-week and 9.7-week (average) course of twice-daily wound treatment with PRP suspended on a collagen base, 61.1% and 88.9% of chronic lower extremity ulcers underwent to 100% reepithelization compared with 40% and 60% of controls (n = 10) treated with hyaluronic acid and collagen medication. In patients treated with reconstructing three-dimensional projection of face by fat grafting and PRP, we observed a 70% maintenance of contour restoring and three-dimensional volume after 1 year compared to only 31% of controls (n = 10) treated with fat grafting alone. In vitro, PRP induced a significant increase in the number of adipose-tissue-derived stem cells compared to control cultures. These results documented that PRP accelerates chronic skin ulcer reepithelization and improves maintenance and function of fat graft in patients who underwent plastic reconstructive surgery, possibly by stimulating adipose-tissue-derived stem cell proliferation.

Scintigraphic evaluation of early osteoblastic activity in extraction sockets treated with platelet-rich plasma

PURPOSE

The aim of this study was to investigate the early effect of platelet-rich plasma (PRP) on osteoblastic activity during the healing process of soft tissue impacted mandibular third molar extraction sockets by means of bone scintigraphy.

PATIENTS AND METHODS

Twelve patients with bilaterally soft tissue impacted mandibular third molars were included in the study. The impacted right and left mandibular third molars were surgically extracted in the same session. PRP was administered randomly into the extraction sockets in the study (S) group whereas the extraction sockets in the control (C) group were left without PRP treatment. Scintigrams were obtained in the first and fourth weeks after surgery to evaluate the osteoblastic activity within extraction sockets in both groups.

RESULTS

Scintigraphic findings of postoperative first and fourth weeks did not show significantly increased osteoblastic activity between S group and C group (P > .05). However, the osteoblastic activity in both groups significantly increased in postoperative week 4 in comparison to week 1 (P < .05).

CONCLUSION

The application of PRP alone into soft tissue impacted mandibular third molar extraction sockets failed to increase the osteoblastic activity in postsurgical weeks 1 and 4 in comparison to non-PRP-treated sockets.

The usefulness of 111indium-oxine autologous platelet gel graft imaging to evaluate osteoinduction in patients undergoing surgery of jaw bone defects

Autologous platelet gel (AGP) is a source of concentrated growth factors contained in the platelet granules used to enhance bone quality and, especially, quicken bone formation in regeneration techniques, and also ameliorate the haemostasis in anti-coagulated patient management. The purpose of this study is to describe a technique to perform labelling of autologous platelet-gel with 111In -Oxine and to evaluate its usefulness, as a marker of bone osteoinduction by means of scintigraphy, after in vivo application in patients with jaw bone defects following cystic lesion enucleation and the extraction of deeply impacted lower third molar. All patients included in the study presented mandible bone defects following cyst enucleation or deeply impacted lower third molar extraction. In sterile conditions, 111In-Oxine AGP was added during the bone-milling phase of the graft preparation and then applied to the bone defects. The scintigraphy was performed 2 hours after the application of labelled AGP (early scan) and at 24, 48, 72, 384 hours (delayed scan). At early scan all the patients presented a high concentration of 111In-Oxine AGP, which was easily recognized at the level of jaw defect. Limited diffusion of AGP was seen in the tissue surrounding the bone defect; this activity was attributed to the presence, in the PRP, of a quote of autologous granulocytes, as marker of inflammatory process, which was labelled with 111In-Oxine. In order to demonstrate the persistence and stability of labelling AGP, abdominal scintigraphies were performed to assess the presence of activity in the liver, spleen and bone marrow. None of the patients presented appreciable activity in these organs. The labelled AGP topically applied showed high uptake values, without statistically significant activity in the surrounding tissues or in critical organs during the early phase, as well as in delayed controls, and confirmed a very low grade of loss of 111In-Oxine from the bone defect. The scintigraphy represents a useful method of assessing the success of surgical procedure for jaw bone defects performed with autogenous grafts. It is well accepted by the patients, offering at the same time a sensitive method of studying uptake of topically applied AGP and to follow up kinetics of AGP in order to correlate quantitative data of the platelet gel life span with evolution of the bone remodelling process. Finally, the labelled granulocytes around the bone defect allow to assess the inflammatory process evolution derived from the surgical technique.

Dentoalveolar Procedures for the Anticoagulated Patient: Literature Recommendations Versus Current Practice

PURPOSE

To evaluate the current practice of oral and maxillofacial surgeons in Michigan regarding perioperative warfarin therapy and dentoalveolar surgery in defined procedure risk groups.

MATERIALS AND METHODS

Surveys were distributed to all surgeons (n = 188) registered with the Michigan Society of Oral and Maxillofacial Surgeons. Low/moderate/high surgery risk groups were defined based on retrospective data accumulated for procedures on pretransplant liver failure patients. We requested the surgeon's maximum tolerated International Normalized Ratio (INR) for each risk group. In addition, surgeons were asked if their routine practice for each group included continuation or discontinuation of therapeutic warfarin perioperatively.

RESULTS

A 72.6% response rate was achieved. The average maximum INR cutoff values for the various risk groups were: low, 2.68; moderate, 2.28; and high, 2.01. Routine discontinuation of warfarin occurred in these groups 23.6%, 48.8%, and 70.5%, respectively. Using a paired t test, these results showed statistically significant differences in patient management practices (P < .001) between the low, moderate, and high risk groupings.

CONCLUSION

Lack of uniformity exists regarding warfarin therapy and dentoalveolar surgery. No studies to date involve significant numbers of moderate/high risk procedures to provide evidence-based support of safety with maintenance of therapeutic INR. For moderate or high risk procedures, the majority of surgeons prefer warfarin discontinuation with minimally therapeutic or subtherapeutic levels, a practice that secondarily increases risk for thromboembolism. Based on these preliminary data, we believe a prospective trial to elucidate stronger management guidelines for both the moderate and high risk surgery population is indicated.

Flow cytometric and morphological characterization of platelet-rich plasma gel

BACKGROUND OF PROBLEMS: Platelet-rich plasma (PRP) gel is derived from an autogenous preparation of concentrated platelets and is widely used in implant dentistry as a vector for cell growth factors. However, limited data are available on its structure and composition. The present study was aimed at providing a flow cytometric and ultrastructural characterization of PRP gel.

MATERIALS AND METHODS

Twenty PRP gel samples were obtained from healthy volunteers. These PRP gel specimens were prepared for transmission (TEM) and scanning electron microscopy (SEM) examination of their morphological ultrastructure. Flow cytometry with CD41-PE monoclonal antibody was used to detect platelet cells, as this antibody recognizes human-platelet-specific antigen CD41.

RESULTS

Both SEM and TEM showed that PRP gel contains two components: a fibrillar material with striated band similar to fibrin filaments, and a cellular component that contains human platelet cells. Both techniques indicated that no morphological elements were bound between the cellular component and the fibrillar material. The cells were confirmed as platelet cells by flow cytometric study after incubation with specific monoclonal antibody CD41-PE.

CONCLUSION

PRP gel contains a fibrillar and a cellular (largely human platelet cell) component. This unique structure may be capable of acting as a vehicle for carrying of cells that are essential for soft/hard tissue regeneration.

Effect of Platelet Rich Plasma and Fibrin Sealant on Facial Nerve Regeneration in a Rat Model

OBJECTIVE

To investigate the effects of platelet rich plasma (PRP) and fibrin sealant (FS) on facial nerve regeneration.

STUDY DESIGN

Prospective, randomized, and controlled animal study.

METHODS

Experiments involved the transection and repair of facial nerve of 49 male adult rats. Seven groups were created dependant on the method of repair: suture; PRP (with/without suture); platelet poor plasma (PPP) (with/without suture); and FS (with/without suture) groups. Each method of repair was applied immediately after the nerve transection. The outcomes measured were: 1) observation of gross recovery of vibrissae movements within 8-week period after nerve transection and repair using a 5-point scale and comparing the left (test) side with the right (control) side; 2) comparisons of facial nerve motor action potentials (MAP) recorded before and 8 weeks after nerve transection and repair, including both the transected and control (untreated) nerves; 3) histologic evaluation of axons counts and the area of the axons.

RESULTS

Vibrissae movement observation: the inclusion of suturing resulted in overall improved outcomes. This was found for comparisons of the suture group with PRP group; PRP with/without suture groups; and PPP with/without suture groups (P < .05). The PRP without suture group had a significantly greater degree of recovery than the PPP without suture group (P < .05), but it did not have better performance than suture group (P > .05). The movement recovery of the suture group was significantly better than the FS group (P = .014). The recovery of function of the PRP groups was better than that of the FS groups, although this did not reach statistical significance (P = .09). Electrophysiologic testing: there was a significantly better performance of the suture group when compared with the PRP and PPP without suture groups in nerve conduction velocity (P < .05). The PRP with suture group had the best results when compared with the suture as well as the PPP with suture groups in duration and latency-2 of MAP (P < .05). For the FS groups, no results were found demonstrating a biological effect. The PRP with suture group demonstrated the best performance in the latency-2 and the area under the curve of MAP when compared with the suture and FS with suture groups (P < .05). Histomorphometric analysis: PRP with suture demonstrated the greatest increase in axon counts when compared with suture, FS with suture, and PPP with suture groups (P < .05). There was no statistically significant difference seen in axon diameter.

CONCLUSION

The best results for the return of function in our rat facial nerve axotomy models occurred when the nerve ends were sutured together. At the same time, the data demonstrated a measurable neurotrophic effect when PRP was present, with the most favorable results seen with PRP added to suture. There was an improved functional outcome with the use of PRP in comparison with FS or no bioactive agents (PPP). FS showed no benefit over conventional suturing in facial nerve regeneration. Our study provides the potential of a new clinical application for PRP in peripheral nerve regeneration.

Platelet-rich plasma: a review of biology and applications in plastic surgery

Healing of hard and soft tissue is mediated by a complex array of intracellular and extracellular events that are regulated by signaling proteins, a process that is, at present, incompletely understood. What is certain, however, is that platelets play a prominent if not deciding role. Controlled animal studies of soft and hard tissues have suggested that the application of autogenous platelet-rich plasma can enhance wound healing. The clinical use of platelet-rich plasma for a wide variety of applications has been reported; however, many reports are anecdotal and few include controls to definitively determine the role of platelet-rich plasma. The authors describe platelet biology and its role in wound healing; the preparation, characterization, and use of platelet-rich plasma; and those applications in plastic surgery for which it may be useful.