CT Lesion Model-Based Structural Allografts: Custom Fabrication and Clinical Experience.

BACKGROUND: Patients requiring knee and hip revision arthroplasty often present with difficult anatomical situations that limit options for surgery. Customised mega-implants may be one of few remaining treatment options. However, extensive damage to residual bone stock may also be present, and in such cases even customised prosthetics may be difficult to implant. Small quantities of lost bone can be replaced with standard allografts or autologous bone. Larger defects may require structural macro-allografts, sometimes in combination with implants (allograft-prosthesis composites). METHODS: Herein, we describe a process for manufacturing lesion-specific large structural allografts according to a 3D, full-scale, lithographically generated defect model. These macro-allografts deliver the volume and the mechanical stability necessary for certain complex revisions. They are patient-and implant-matched, negate some requirements for additional implants and biomaterials and save time in the operating theatre by eliminating the requirement for intra-operative sizing and shaping of standard allografts. CONCLUSION: While a robust data set from long-term follow-up of patients receiving customised macro-allografts is not yet available, initial clinical experience and results suggest that lesion-matched macro-allografts can be an important component of revision joint surgery.

Coding of tissue preparations with eurocode in Germany.

SUMMARY: A safe look back of products requires their unique identification. Blood products are encoded in Germany with Eurocode since 1987. EU Directives 2004/23/EC und 2006/86/EC demanded unique identification and safe look back procedure also for tissues and cells. Eurocode IBLS e.V. and the DGTI working parties 'Tissue Preparations' and 'Automation and Data Processing' supplemented the already available Eurocode nomenclature for blood products with further data structures for tissue preparations and deliberated the federal authorities during the EU hearings. In result all EU member states can administer the coding system oneself, but have to take care about the 'key code' structure as defined and the common part at the begin of the ID number of the preparations. Eurocode today offers an EU-conform coding system considering various aspects of blood, tissue and cell preparations in an ISO-standardized form.

"Eurocode International Blood Labeling System" enables unique identification of all biological products from human origin in accordance with the European Directive 2004/23/EC.

Due to their limited availability and compatibility, biological products must be exchanged between medical institutions. In addition to a number of national systems and agreements which strive to implement a unique identification and classification of blood products, the ISBT 128 was developed in 1994, followed by the Eurocode in 1998. In contrast to other coding systems, these both make use of primary identifiers as stipulated by the document ISO/IEC 15418 of the International Organization for Standardization (ISO), and thus provide a unique international code. Due to their flexible data structures, which make use of secondary identifiers, both systems are able to integrate additional biological products and their producers. Tissue and cells also constitute a comparable risk to the recipient as that of blood products in terms of false labeling and the danger of infection. However, in contrast to blood products, the exchange of tissue and cells is much more intensively pursued at the international level. This fact is recognised by Directives 2004/23/EC and 2006/86/EC of the European Union (EU), which demand a standardized coding system for cells and tissue throughout the EU. The 2008 workshop agreement of the European Committee for Standardization (CEN) was unique identification by means of a Key Code consisting of country code corresponding to ISO 3166-1, as well as competent authority and tissue establishment. As agreed at the meeting of the Working Group on the European Coding System for Human Tissues and Cells of the Health and Consumers Directorate-General of the European Commission (DG SANCO) held on 19 May 2010 in Brussels, this Key Code could also be used with existing coding systems to provide unique identification and allow EU traceability of all materials from one donation event. Today Eurocode already uses country codes according to ISO 3166-1, and thus the proposed Key Code can be integrated into the current Eurocode data structure and does not need to be introduced separately. The Eurocode product classification for all products is based on its own unique coding system, which can be accessed over the internet by all users who are not themselves members of Eurocode. In summary, it can be said that the standardized single coding system for tissues and cells requires only unique sections in the data structure such the Key Code to fulfil the requirements of the EU Directive. Thus, various systems currently in place in different EU member states can continue to operate if the Key Code as suggested by the EU is integrated into them. The classification and description of each product characteristic is currently being discussed by the DG SANCO Working Group on the European Coding System for Human Tissues and Cells. Following intensive scrutiny in light of the stipulations laid out in EU Directives 2004/23/EC and 2006/86/EC as well as the CEN/ISSS workshop agreements, the Germany Federal Ministry for Health and organisations representing German tissue establishments under the responsibility of the German Society of Transfusion Medicine and Immunohematology, Working Party "Tissue preparations" proposed in 2009 that Eurocode be adopted for the donor identification and product coding of tissue and cells in Germany. The technical details for implementation have already been completed and are presented in the current article.

No influence of collagenous proteins of Achilles tendon, skin and cartilage on the virus-inactivating efficacy of peracetic acid-ethanol.

The risk of transmitting human pathogenic viruses via allogeneic musculoskeletal tissue transplants is a problem requiring effective inactivation procedures. Virus safety of bone transplants was achieved using peracetic acid (PAA)-ethanol sterilisation. Proteins are known to have an adverse effect on the virus-inactivating capacity of PAA. Therefore we investigated virus inactivation by PAA in collagenous tissues. Achilles tendon, skin and cartilage were cut into small pieces, lyophilised and contaminated with pseudorabies virus (PRV) or porcine parvovirus (PPV). The inactivating capacity of PAA-ethanol was investigated by determining virus titres in the supernatant or the tissue pellet at different time-points. In all virus-contaminated tissue samples treatment for 10 min with PAA-ethanol resulted in titre reductions by a factor of >10(3). PRV was rapidly inactivated below the detection limit (< or =2.8 x 10(1) TCID(50)/ml). After 240 min a reduction by a factor of >10(4) was obtained for PPV in all samples, but a residual infectivity remained. Collagenous proteins of Achilles tendon, skin and cartilage had no adverse effect on the virus-inactivating capacity of PAA. PAA-ethanol used in the production process at the Charité tissue bank can therefore be recommended for treatment of non-osseous musculoskeletal tissues.

Distraction forces on repaired bucket-handle lesions in the medial meniscus.

BACKGROUND: Numerous studies have investigated the biomechanical properties of meniscal repair techniques. One of the most commonly discussed parameters is the failure load in the axis of insertion, although little is known about the distraction forces actually occurring at repaired bucket-handle lesions. HYPOTHESIS: There are clinically relevant distraction forces on repaired meniscus bucket-handle lesions. STUDY DESIGN: Controlled laboratory study. METHODS: Meniscus bucket-handle lesions were created and repaired in human cadaveric knees with a vertical suture made from a braided steel wire. A small-sized load sensor was connected to the wire at the periphery of the meniscus. The distraction forces acting on the lesion were measured at different knee joint angles (0 degrees -120 degrees of flexion) with internal and external rotation and with and without weight loading. Forces in excess of 10 N were considered to have clinical relevance. RESULTS: Mean forces on the meniscus repair ranged from 1.64 to 4.72 N. Irrespective of the modalities (ie, different flexion angles, weight load, direction of rotation), it was found that the forces were well below the cutoff value of 10 N (P < .01). Increasing flexion angles generally did not cause an increase in distraction forces. CONCLUSION: The data suggest that distraction forces are not the primary factor in the mechanical stability of meniscal repair. It must therefore be assumed that other factors such as shear forces are of greater significance. CLINICAL RELEVANCE: The results may help to validate the biomechanical properties of different meniscal repair techniques.

A method for the determination of the residual chloroform in defatted cancellous bone transplants.

The removal of fat from cancellous bone tissue promotes the clinical healing of the transplant and improves the penetration of chemical sterilisation media into the tissue. Treatment using chloroform/methanol (2:1, 2 h) is frequently used as a defatting procedure. Eight rinses with methanol followed by two rinses with aqua ad iniectabilia (20 min each, with ultrasonic effect) ensure depletion in the level of chloroform from defatted cancellous bone to a concentration below 25 ppm (limit value). For the necessary routine quality checks on the production process, a gas chromatography method has been developed that determines the level of chloroform in cancellous bone, for which the detection limit is 0.003 ppm.

Peracetic acid-ethanol treatment of allogeneic avital bone tissue transplants--a reliable sterilization method.

OBJECTIVES: Based on the European Standard EN 1040, the validation guidelines of the German Federal Institute for Drugs and Medical Devices and CPMP guidelines we tested the antimicrobial effectiveness of a peracetic acid-ethanol sterilization procedure (PES) in allogenic avital bone transplants. STUDY DESIGN: Delipidated human bone spongiosa cubes (15 x 15 x 15 mm) served as tissue. Three enveloped viruses (human immunodeficiency virus type 2, pseudorabies virus, bovine virus diarrhoea virus) and three non-enveloped viruses (hepatitis A virus, poliovirus, porcine parvovirus) were used. The reduction of virus infectivity was measured as TCID50/ml in neutralized supernatants and bone homogenates. Staphylococcus aureus. Enterococcus faecium, Pseudomonas aeruginosa. Bacillus subtilis. Clostridium sporogenes, Mycobacterium terrae. Candida albicans, Aspergillus niger as well as spores of Bacillus subtilis were tested additionally. PES led to a reduction of virus titres by more than 4 log10. Only HAV showed a reduction below 4 log10 (2.87) with residual infectivity. After including a delipidating step for HAV-infected cells, a reduction of over 7 log10 HAV titre was found. For viable bacteria, fungi and spores a titre reduction below the detection level (5 log10) was achieved after an incubation time of 2 hours. CONCLUSIONS: The peracetic acid-ethanol procedure proved to be a reliable method for the sterilization of human bone transplants (layer thickness < or = 15 mm). However, additional safety measures (anamnestic informations, infectious serology, HIV-/HBV-/HCV-PCR in case of multiorgan donors) should be taken.

Good preservation of initial mechanical properties in lipid-extracted, disinfected, freeze-dried sheep patellar tendon grafts.

Patellar tendon allografts can be used for anterior cruciate reconstruction to avoid morbidity of autografts on the donor side. Secondary processing of allografts is important for reducing immunological reactions, bacterial contamination and improving storage. We analyzed the effects of processing on the mechanical properties of patellar tendon grafts in 20 sheep. Group I (n = 10) was deep-frozen at -80 degrees C. Group II (n = 10) was processed by a lipid extraction/ freeze-drying method, including iodoacetic acid disinfection. The contralateral tendons, freeze-dried by dehydration in a vacuum at -50 degrees C for 3 hours, served as controls. We measured failure stress: group I (53, SD 14 MPa), control (26, SD 15 MPa) (p = 0.04); group II (49, SD 13 MPa), control (28, SD 5 MPa) (p = 0.08). Failure strain, normalized stiffness, and energy to failure were similar in the groups. Our method of extended processing did not change the properties of the deep-frozen patellar tendons. Therefore in vivo experiments can be used when studying the effects of transplantation on mechanical properties.

Reconstruction of the frontal calvarian continuity in a child using a freeze-preserved autogenous bone graft.

Today, extended craniofacial defects in childhood can be treated by using modern techniques of bone banking and osteosynthesis, of particular importance when the restoration needs to consider calvarial growth. This is a report of an 8-year-old boy whose right frontal bone was removed during primary multidisciplinary trauma care. The bone was stored at a tissue bank using sterilization and freeze-dried preservation. Nine months later the graft was replaced and fixed with resorbable miniplates. Postoperatively no complications were observed and the (auto)graft has taken well. There was symmetrical craniofacial growth as well as a good aesthetic result three years after reconstruction.

Effect of gamma irradiation on human cortical bone transplants contaminated with enveloped and non-enveloped viruses.

In the production of bone grafts intended for transplantation, basic safety measures to avoid the transmission of pathogens are selection and serological screening of donors for markers of virus infections. As an additional safety tool we investigated the effect of gamma irradiation on the sterility of human bone diaphysis transplants and evaluated its impact on the virus safety of transplants. Model viruses were included in the study to determine the dose necessary to achieve a reduction factor for the infectivity titres of at least 4 log(10) at a temperature of -30+/-5 degrees C. The following viruses were used: human immunodeficiency virus type 2 (HIV-2), hepatitis A virus (HAV), and poliovirus (PV-1), and the following model viruses: pseudorabies virus (PRV) as a model for human herpesviruses, bovine viral diarrhoea virus (BVDV) for HCV, and bovine parvovirus (BPV) for parvovirus B19. A first approach was to determine the D(10) values (kGy) for the different viruses (virus inactivation kinetics: BPV 7.3; PV-1 7.1; HIV-2 7.1; HAV 5.3; PRV 5.3; BVDV <3.0 kGy). Based on these results, inactivation of these viruses was studied in experimentally contaminated human bone transplants (femoral diaphyses). For BPV, the most resistant one of the viruses studied, a dose of approximately 34 kGy was necessary to achieve a reduction of infectivity titres of 4 log(10). We therefore recommend a dose of 34 kGy for the sterilisation of frozen bone transplants.

Clinical efficacy and compatibility of allogeneic avital tissue transplants sterilized with a peracetic acid/ethanol mixture.

In the course of the past 20 years a quantity of approximately 60,000 allogeneic avital tissue grafts sterilized with the peracetic acid-ethanol method (PES) were transplanted successfully. Based on a retrospective report of clinical experience of the years 1997-2001 on the overall scope of tissue grafts manufactured by the Tissue Banks of the University Hospital Charité and the German Institute for Cell and Tissue Replacement, the clinical efficacy and side effects of 18.3% (3.087/16.823) of all transplants were studied. Cancellous (1.601/3.087) and cortical (291/3.087) bone transplants as well as amnion (1.027/3.087) constituted the greatest part. In 91% of the examined patients (2.369/2.592) tissue integration ratios ranging from good up to very well could be observed. The transplant function of defect replacement or of a spacer respectively could be obtained for all types of tissue. The clinical effect caused by the transplant resulted in more than 99% of the transplants in primary integration or in the desired aim of the therapy (defect replacement, stabilization in case of palliative operations, etc.). In less than 1% (9/2.592) of cases a secondary healing occurred for cancellous bone transplantations or, revisional operations became necessary. In all cases severe side effects, in particular transmission of infectious diseases or transplant rejections, were not observed.

The establishment of a network of European human research tissue banks.

This is a report of a workshop held on the establishment of human research tissue banking which was held in Levi, Finland 21-24 March 2002. There were 21 participants from 7 European countries. This meeting was attended by representatives from academia, research tissue banks and from the Biotech and Pharmaceutical Industries. The principal aim of the workshop was to find a way to progress the recommendations from ECVAM workshop 44 (ATLA 29, 125-134, 2001) and ECVAM workshop 32 (ATLA 26, 763-777, 1998). The workshop represented the first unofficial meeting of the European Network of Research Tissue Banks (ENRTB) steering group. It is expected that in the period preceding the next workshop the ENRTB steering group will co-ordinate the ethical, legislative and organisational aspects of research tissue banking. Key issues dealt with by the Levi workshop included the practical aspects of sharing expertise and experiences across the different European members. Such collaboration between research tissue banks and end users of such material seeks to ultimately enable shared access to human tissue for medical and pharmaco-toxicological research while maintaining strict adherence to differences in legal and ethical aspects related to the use of human tissue in individual countries.