Platelet rich plasma for the prevention of osteoradionecrosis. A double blinded randomized cross over controlled trial

Abstract

Osteoradionecrosis of the jaws is a complication of radiotherapy and controversy remains about the management of teeth in the field of radiotherapy. Platelet rich plasma has been advocated in multiple surgical sites, both bone and soft tissue, to promote healing and reduce complications. A randomized double blinded controlled trial was performed on patients receiving bilateral radiotherapy that affected the mandible who required pre treatment dental extractions. One side received platelet rich plasma and the other acted as a control. Twenty-two patients were recruited over 12 months and over a 5-year period following treatment three developed osteoradionecrosis (14%). Platelet rich plasma failed to show any benefit in the prevention of osteoradionecrosis. Nor was there any benefit in pain scores or mucosal healing on sides that were treated with platelet rich plasma. Platelet rich plasma fails to show a benefit in the prevention of osteoradionecrosis. The rate of osteoradionecrosis is high compared to other published series and the prophylactic removal of molar teeth should be questioned as a preventative measure.

Introduction

Radiotherapy is an integral component of the management of head and neck cancer. Although recent advances in delivery techniques have minimized damage to surrounding tissues, the side effects of treatment remain significant. The mandible, in particular, is sensitive to radiotherapy and osteoradionecrosis (ORN) remains one of the most feared complications of treatment. Its incidence ranges from 5 to 15% depending on the series and considerable controversy remains with regards to the management of the dentition in the mandible prior to radiotherapy . The rate of ORN is lower in patients who are edentulous at the time of presentation and the practice of dental extraction of even pathologically normal ‘in field’ teeth is widespread prior to radiotherapy in an attempt to minimize the risk. Recent studies have called into question this practice .

The exact pathogenesis of radiotherapy in ORN is unknown, though an evolution from M arx ‘s ‘hypoxic, hypocellular and hypovascular’ theory towards the fibroatrophic theory of D elanian & L efaix is underway. Irrespective of the pathogenesis of ORN, there is little argument that an adequate healing time is required between dental extractions and the commencement of radiotherapy. Primary mucosal coverage of extraction sockets is thought to be important, though the importance of the underlying bone remodelling, which can go on for months, is unknown.

Platelet rich plasma (PRP) is an autologous blood product created by spinning whole blood in a centrifuge to isolate a platelet rich ‘buffy coat’. Platelets contain growth factors including platelet derived growth factor (PDGF), transforming growth factor beta (TGFβ) and vascular endothelial growth factor (VEGF). The use of PRP has been extensively promoted for improving the survival of bone grafts, in dental implantology, cosmetic surgery and orthopaedic procedures . Despite good theoretical reasons for efficacy, there is still controversy surrounding its use and the majority of published studies are case series or unblinded trial. Systematic reviews have failed to show the benefit of PRP in bone grafting of the maxillary sinus , face lift surgery , and fracture healing .

The principal aim of this study was to determine whether PRP in dental extraction sockets prior to radiotherapy could help to prevent ORN of the mandible. The secondary aim of the study was to determine its effects on wound pain.

Materials and methods

The study design was a double blinded randomized cross over controlled trial. Ethical approval was granted by the Royal Brisbane Hospital Human Research and Ethics Committee.

Patients were recruited from the Hospital’s head and neck clinic in 2003 over a 12-month period. At the time of recruitment, prophylactic dental extractions were performed for posterior mandibular teeth in the field of radiotherapy. All patients had a diagnosis of head and neck cancer that required bilateral external beam radiotherapy and affected the posterior mandible.

Patients were offered participation in the study if they met the following inclusion criteria: the ability to comprehend the study and give informed consent; bilateral posterior mandibular teeth in the field of radiotherapy; and were aged over 18 years at the time of diagnosis. Patients were excluded from the study if they had: overtly pathologic teeth with either periodontal or periapical infection; a history of radiotherapy to the head and neck.

Following recruitment, patients were randomized at the time of surgery to receive PRP to either the right or left side. The surgical technique consisted of atraumatic extraction, limited alveoloplasty and primary closure. The treatment side received PRP harvested using the 3i PCCS system according to the manufacturer’s instructions, placed in the sockets with cellulose foam, and activated with the patient’s whole blood and calcium chloride. The control side received cellulose foam only. The patient was blinded as to the side and all surgical procedures were carried out by the senior author (CA).

Assessment was undertaken by either of two experienced surgical trainees who were blinded as to the side receiving PRP. Patients were reviewed at 2 weeks, then 2, 6, 9 and 12 months. A 5-year review of all patient notes was undertaken to determine survival and late development of ORN. Data were collected on bone exposure and pain (self reported via a Likert scale ranging from 1 to 10).

ORN was defined as exposed bone in a field of radiotherapy persisting for more than 3 months. Additional data were collected on demographic details, tumour, nodes, metastases (TNM) status, duration between dental extraction and commencement of radiotherapy and dose/fields of radiotherapy.

Fisher’s exact test was used to determine whether there were any differences between the treatment side and the presence of ORN. To determine whether there were any differences in the pain scores of the treatment sides, a paired-samples t test was used to assess the differences over the five time-points. Independent sample t tests were used to assess differences in the time of dental extraction and dose radiation to ORN and no ORN patients. All statistical analyses were performed in SPSS Statistics Version 17.0.

Materials and methods

The study design was a double blinded randomized cross over controlled trial. Ethical approval was granted by the Royal Brisbane Hospital Human Research and Ethics Committee.

Patients were recruited from the Hospital’s head and neck clinic in 2003 over a 12-month period. At the time of recruitment, prophylactic dental extractions were performed for posterior mandibular teeth in the field of radiotherapy. All patients had a diagnosis of head and neck cancer that required bilateral external beam radiotherapy and affected the posterior mandible.

Patients were offered participation in the study if they met the following inclusion criteria: the ability to comprehend the study and give informed consent; bilateral posterior mandibular teeth in the field of radiotherapy; and were aged over 18 years at the time of diagnosis. Patients were excluded from the study if they had: overtly pathologic teeth with either periodontal or periapical infection; a history of radiotherapy to the head and neck.

Following recruitment, patients were randomized at the time of surgery to receive PRP to either the right or left side. The surgical technique consisted of atraumatic extraction, limited alveoloplasty and primary closure. The treatment side received PRP harvested using the 3i PCCS system according to the manufacturer’s instructions, placed in the sockets with cellulose foam, and activated with the patient’s whole blood and calcium chloride. The control side received cellulose foam only. The patient was blinded as to the side and all surgical procedures were carried out by the senior author (CA).

Assessment was undertaken by either of two experienced surgical trainees who were blinded as to the side receiving PRP. Patients were reviewed at 2 weeks, then 2, 6, 9 and 12 months. A 5-year review of all patient notes was undertaken to determine survival and late development of ORN. Data were collected on bone exposure and pain (self reported via a Likert scale ranging from 1 to 10).

ORN was defined as exposed bone in a field of radiotherapy persisting for more than 3 months. Additional data were collected on demographic details, tumour, nodes, metastases (TNM) status, duration between dental extraction and commencement of radiotherapy and dose/fields of radiotherapy.

Fisher’s exact test was used to determine whether there were any differences between the treatment side and the presence of ORN. To determine whether there were any differences in the pain scores of the treatment sides, a paired-samples t test was used to assess the differences over the five time-points. Independent sample t tests were used to assess differences in the time of dental extraction and dose radiation to ORN and no ORN patients. All statistical analyses were performed in SPSS Statistics Version 17.0.

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Jan 26, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Platelet rich plasma for the prevention of osteoradionecrosis. A double blinded randomized cross over controlled trial
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