Successful disinfection of femoral head bone graft using high hydrostatic pressure

Abstract

The current standard for sterilization of potentially infected bone graft by gamma irradiation and thermal or chemical inactivation potentially deteriorates the biomechanical properties of the graft. We performed an in vitro experiment to evaluate the use of high hydrostatic pressure (HHP); which is widely used as a disinfection process in the food processing industry, to sterilize bone grafts. Four femoral heads were divided into five parts each, of which 16 were contaminated (in duplicate) with 105–107 CFU/ml of Staphylococcus epidermidis, Bacillus cereus, or Pseudomonas aeruginosa or Candida albicans, respectively. Of each duplicate, one sample was untreated and stored similarly as the treated sample. The remaining four parts were included as sterile control and non-infected control. The 16 parts underwent HHP at the high-pressure value of 600 MPa. After HHP, serial dilutions were made and cultured on selective media and into enrichment media to recover low amounts of microorganism and spores. Three additional complete femoral heads were treated with 0, 300 and 600 MPa HHP respectively for histological evaluation. None of the negative-control bone fragments contained microorganisms. The measured colony counts in the positive-control samples correlated excellent with the expected colony count. None of the HHP treated bone fragments grew on culture plates or enrichment media. Histological examination of three untreated femoral heads showed that the bone structure remained unchanged after HHP. Sterilizing bone grafts by high hydrostatic pressure was successful and is a promising technique with the possible advantage of retaining biomechanical properties of bone tissue.

Systematic enhancement of microbial decontamination efficiency in bone graft processing by means of high hydrostatic pressure using Escherichia coli as a model organism

“…35,47 Considering the few other studies on the major hurdles, as suggested by the varying success rates. 18,37,41 From a biomechanical point of view, an application of up to 600 MPa would be acceptable. Biomechanical integrity of various musculoskeletal tissues has been proven to sustain even when hydrostatic pressures of up to 600 MPa were applied.…”

“…If an allograft is treated with peracetic acid/ethanol, gamma irradiation, or humid heat, using the bone tissue in load-bearing defect regions might not be possible. 3,18,19 Additionally, processing of musculoskeletal tissues often involves a decellularization step to minimize possible immunological reactions by the recipient by maintaining only the immunologically inert extracellular matrix. 1 Processing technologies that combine effective decellularization and sterilization, but preserve the biomechanical integrity, are required.…”

“…However, only a few studies investigated the decontaminating effects of HHP in bone processing, with varying success rates. 18,37,40,41 Establishing a fast and linear bone graft processing method that retains biomechanical integrity, keeps the immunogenic burden low, and reduces bioburden might benefit patient's health and safety after allogeneic bone reconstruction. The potential capability to improve tissue preservation in a one-step treatment covering both devitalization and decontamination makes HHP treatment worth studying as a processing technique.…”

Osteogenic differentiation of mesenchymal stem cells cultured on allogenic trabecular bone grafts treated with high hydrostatic pressure

“…For HHP it was already shown that pressures up to 600 MPa can successfully disinfect bone contaminated with bone specific pathogens. 14,45 However, those pressure levels lead to necrosis of cells, which in turn results in the release of damage associated molecular patterns resulting in the activation of the immune system of the host. 20,46 Therefore, it would be optimal, to develop a process protocol to which cells react primarily apoptotic and a decontaminating effect can be achieved.…”

Safety and Reoperation Rates in Non-instrumented Lumbar Fusion Surgery: Secondary Report From a Randomized Controlled Trial of ABM/P-15 vs Allograft With Minimum 5 years Follow-Up

“…However, harvesting and utilizing allograft is labor intensive as it has to be processed, and the donor must be screened at least twice for potential contagious diseases. 10,11 Another drawback is the numerous reports on inferior fusion rates compared to autograft. 12 For these reasons, a readily available bone graft extender, enhancer or substitute would be a welcome addition to the available options for the spine surgeons performing fusions.…”