The broad use of the Pm8 resistance gene in wheat resulted in hypermutation of the AvrPm8 gene in the powdery mildew pathogen

BACKGROUND

Worldwide wheat production is under constant threat by fast-evolving fungal pathogens. In the last decades, wheat breeding for disease resistance heavily relied on the introgression of chromosomal segments from related species as genetic sources of new resistance. The Pm8 resistance gene against the powdery mildew disease has been introgressed from rye into wheat as part of a large 1BL.1RS chromosomal translocation encompassing multiple disease resistance genes and yield components. Due to its high agronomic value, this translocation has seen continuous global use since the 1960s on large growth areas, even after Pm8 resistance was overcome by the powdery mildew pathogen. The long-term use of Pm8 at a global scale provided the unique opportunity to study the consequences of such extensive resistance gene application on pathogen evolution.

RESULTS

Using genome-wide association studies in a population of wheat mildew isolates, we identified the avirulence effector AvrPm8 specifically recognized by Pm8. Haplovariant mining in a global mildew population covering all major wheat growing areas of the world revealed 17 virulent haplotypes of the AvrPm8 gene that grouped into two functional categories. The first one comprised amino acid polymorphisms at a single position along the AvrPm8 protein, which we confirmed to be crucial for the recognition by Pm8. The second category consisted of numerous destructive mutations to the AvrPm8 open reading frame such as disruptions of the start codon, gene truncations, gene deletions, and interference with mRNA splicing. With the exception of a single, likely ancient, gain-of-virulence mutation found in mildew isolates around the world, all AvrPm8 virulence haplotypes were found in geographically restricted regions, indicating that they occurred recently as a consequence of the frequent Pm8 use.

CONCLUSIONS

In this study, we show that the broad and prolonged use of the Pm8 gene in wheat production worldwide resulted in a multitude of gain-of-virulence mechanisms affecting the AvrPm8 gene in the wheat powdery mildew pathogen. Based on our findings, we conclude that both standing genetic variation as well as locally occurring new mutations contributed to the global breakdown of the Pm8 resistance gene introgression.

Global genomic analyses of wheat powdery mildew reveal association of pathogen spread with historical human migration and trade

The fungus Blumeria graminis f. sp. tritici causes wheat powdery mildew disease. Here, we study its spread and evolution by analyzing a global sample of 172 mildew genomes. Our analyses show that B.g. tritici emerged in the Fertile Crescent during wheat domestication. After it spread throughout Eurasia, colonization brought it to America, where it hybridized with unknown grass mildew species. Recent trade brought USA strains to Japan, and European strains to China. In both places, they hybridized with local ancestral strains. Thus, although mildew spreads by wind regionally, our results indicate that humans drove its global spread throughout history and that mildew rapidly evolved through hybridization.

The fungus Blumeria graminis f. sp. tritici causes wheat powdery mildew disease. Here, Sotiropoulos et al. analyze a global sample of 172 mildew genomes, providing evidence that humans drove global spread of the pathogen throughout history and that mildew rapidly evolved through hybridization with local fungal strains.

Host Adaptation Through Hybridization: Genome Analysis of Triticale Powdery Mildew Reveals Unique Combination of Lineage-Specific Effectors

The emergence of new fungal pathogens through hybridization represents a serious challenge for agriculture. Hybridization between the wheat mildew (Blumeria graminis f. sp. tritici) and rye mildew (B. graminis f. sp. secalis) pathogens has led to the emergence of a new mildew form (B. graminis f. sp. triticale) growing on triticale, a man-made amphiploid crop derived from crossing rye and wheat, which was originally resistant to the powdery mildew disease. The identification of the genetic basis of host adaptation in triticale mildew has been hampered by the lack of a reference genome. Here, we report the 141.4-Mb reference assembly of triticale mildew isolate THUN-12 derived from long-read sequencing and genetic map-based scaffolding. All 11 triticale mildew chromosomes were assembled from telomere-to-telomere and revealed that 19.7% of the hybrid genome was inherited from the rye mildew parental lineage. We identified lineage-specific regions in the hybrid, inherited from the rye or wheat mildew parental lineages, that harbor numerous bona fide candidate effectors. We propose that the combination of lineage-specific effectors in the hybrid genome is crucial for host adaptation, allowing the fungus to simultaneously circumvent the immune systems contributed by wheat and rye in the triticale crop. In line with this, we demonstrate the functional transfer of the SvrPm3 effector from wheat to triticale mildew, a virulence effector that specifically suppresses resistance of the wheat Pm3 allelic series. This transfer is the likely underlying cause for the observed poor effectiveness of several Pm3 alleles against triticale mildew and exemplifies the negative implications of pathogen hybridizations on resistance breeding.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

A highly differentiated region of wheat chromosome 7AL encodes a Pm1a immune receptor that recognizes its corresponding AvrPm1a effector from Blumeria graminis

Pm1a, the first powdery mildew resistance gene described in wheat, is part of a complex resistance (R) gene cluster located in a distal region of chromosome 7AL that has suppressed genetic recombination. A nucleotide-binding, leucine-rich repeat (NLR) immune receptor gene was isolated using mutagenesis and R gene enrichment sequencing (MutRenSeq). Stable transformation confirmed Pm1a identity which induced a strong resistance phenotype in transgenic plants upon challenge with avirulent Blumeria graminis (wheat powdery mildew) pathogens. A high-density genetic map of a B. graminis family segregating for Pm1a avirulence combined with pathogen genome resequencing and RNA sequencing (RNAseq) identified AvrPm1a effector gene candidates. In planta expression identified an effector, with an N terminal Y/FxC motif, that induced a strong hypersensitive response when co-expressed with Pm1a in Nicotiana benthamiana. Single chromosome enrichment sequencing (ChromSeq) and assembly of chromosome 7A suggested that suppressed recombination around the Pm1a region was due to a rearrangement involving chromosomes 7A, 7B and 7D. The cloning of Pm1a and its identification in a highly rearranged region of chromosome 7A provides insight into the role of chromosomal rearrangements in the evolution of this complex resistance cluster.

[Successful treatment of a geriatric COVID-19 patient with severe chest trauma : An interdisciplinary case report]

Die Coronaviruserkrankung 2019 (COVID-19) ist eine neu auftretende Infektionskrankheit, die sich weltweit rasch ausgebreitet hat und zu einer hohen Morbidität und Mortalität führt. Klinische Erfahrungen bezüglich des chirurgischen Managements bei COVID-19-Patienten mit schwerem Thoraxtrauma sind limitiert. Hier wird über das interdisziplinäre Management einer geriatrischen COVID-19-Patientin nach schwerem Thoraxtrauma mit pulmonaler Symptomatik bei traumatisch instabiler Rippenserienfraktur und begleitendem Hämatothorax berichtet.

Single residues in the LRR domain of the wheat PM3A immune receptor can control the strength and the spectrum of the immune response

The development of improved plant nucleotide-binding, leucine-rich repeat (LRR) immune receptors (NLRs) has mostly been based on random mutagenesis or on structural information available for specific receptors complexed with the recognized pathogen effector. Here, we use a targeted mutagenesis approach based on the natural diversity of the Pm3 powdery mildew resistance alleles present in different wheat (Triticum aestivum) genotypes. In order to understand the functional importance of the amino acid polymorphisms between the active immune receptor PM3A and the inactive ancestral variant PM3CS, we exchanged polymorphic regions and residues in the LRR domain of PM3A with the corresponding segments of PM3CS. These novel variants were functionally tested for recognition of the corresponding AVRPM3^A2/F2 avirulence protein in Nicotiana benthamiana. We identified polymorphic residues in four regions of PM3A that enhance the immune response, but also residues that reduce it or result in complete loss of function. We found that the identified critical residues in PM3A modify its activation threshold towards different protein variants of AVRPM3^A2/F2 . PM3A variants with a lowered threshold gave a stronger overall response and gained an extended recognition spectrum. One of these variant proteins with a single amino acid change was stably transformed into wheat, where it conferred race-specific resistance to mildew. This is a proof of concept that improved PM3A variants with an enlarged recognition spectrum can be engineered based on natural diversity by exchanging single or multiple residues that modulate resistance function.

Effects of melatonin on the in vitro growth of early antral follicles and maturation of ovine oocytes

This study aimed to evaluate the effect of melatonin on the in vitro culture and maturation of isolated sheep early antral follicles. Isolated early antral follicles were cultured for 12 d in α-minimum essential medium (MEM⁺) alone (control) or α-MEM⁺ added with fixed different concentrations (100, 500, or 1,000 pg/mL) or a sequential concentration of melatonin (MelSeq; day 6 = 100; day 12 = 500 pg/mL). The percentage of morphologically normal follicles was higher (P < 0.05) in 500 pg/mL melatonin than the other treatments at 6 d. Mel 500 also showed a higher rate of fully grown oocytes (P < 0.05) than other treatments. After in vitro culture, reactive oxygen species (ROS) levels in oocytes were similar between Mel 500 and MelSeq, with both being lower (P < 0.05) than other treatments. Oocytes cultured in both Mel 500 and Mel 1000 showed glutathione peroxidase levels similar (P > 0.05) to the control group and higher (P < 0.05) than other treatments. Mitochondrial activity was similar (P > 0.05) among control, Mel 500, and Mel 1000 treatments. Mel 500 treatment presented a higher percentage of germinal vesicle breakdown oocytes than the control group and similar percentages to the other treatments. Follicles cultured in melatonin followed by oocyte maturation with the addition of 500 pg/mL melatonin in maturation medium showed increased (P < 0.05) levels of mitochondrial activity compared to α-MEM⁺ alone. In conclusion, the concentration of 500 pg/mL of melatonin promotes development and decreases ROS levels of ovine oocytes from in vitro grown early antral follicles. Moreover, melatonin increases mitochondrial activity and promotes the acquisition of meiotic competence of these oocytes.

Melatonin improves development, mitochondrial function and promotes the meiotic resumption of sheep oocytes from in vitro grown secondary follicles

The aim of this study was to evaluate follicular survival and development of ovine isolated secondary follicles cultured in medium containing fixed or sequential concentrations of melatonin and further oocyte maturation. Isolated secondary follicles were cultured for 18 days in α-MEM⁺ alone (control) or with different concentrations of melatonin (100, 500 or 1000 pg/mL) or sequential concentrations of melatonin (Mel Seq: Day 6 = 100; Day 12 = 500; Day 18 = 1000 pg/mL). The percentages of morphologically normal follicles and antral cavity formation increased significantly in 1000 pg/mL melatonin compared to the other treatments. After 18 days, 1000 pg/mL melatonin (Mel 100) showed a greater (P < 0.05) follicular diameter than α-MEM⁺, 100 and 500 pg/mL melatonin. In addition, the concentration of 500 pg/mL melatonin showed a higher (P < 0.05) percentage of fully grown oocytes than α-MEM⁺, Mel 100 and Mel Seq treatments. After oocyte maturation, the levels of ROS were lower (P < 0.05) in 1000 pg/mL melatonin (Mel 1000) than in other treatments. Both Mel 1000 and Mel Seq treatments showed significantly higher levels of mitochondrial activity than other treatments. There were no significant differences between 500 and 1000 pg/mL melatonin regarding meiotic stages. In conclusion, the concentration of 1000 pg/mL melatonin maintains survival, promotes follicular development and increases the levels of active mitochondria after in vitro culture of sheep secondary follicles. Moreover, this concentration promotes the meiotic competence of oocytes and decreases the production of ROS during oocyte maturation.

A chromosome-scale genome assembly reveals a highly dynamic effector repertoire of wheat powdery mildew

Blumeria graminis f. sp. tritici (B.g. tritici) is the causal agent of the wheat powdery mildew disease. The highly fragmented B.g. tritici genome available so far has prevented a systematic analysis of effector genes that are known to be involved in host adaptation. To study the diversity and evolution of effector genes we produced a chromosome-scale assembly of the B.g. tritici genome. The genome assembly and annotation was achieved by combining long-read sequencing with high-density genetic mapping, bacterial artificial chromosome fingerprinting and transcriptomics. We found that the 166.6 Mb B.g. tritici genome encodes 844 candidate effector genes, over 40% more than previously reported. Candidate effector genes have characteristic local genomic organization such as gene clustering and enrichment for recombination-active regions and certain transposable element families. A large group of 412 candidate effector genes shows high plasticity in terms of copy number variation in a global set of 36 isolates and of transcription levels. Our data suggest that copy number variation and transcriptional flexibility are the main drivers for adaptation in B.g. tritici. The high repeat content may play a role in providing a genomic environment that allows rapid evolution of effector genes with selection as the driving force.

Multiple pairs of allelic MLA immune receptor-powdery mildew AVRA effectors argue for a direct recognition mechanism

Nucleotide-binding domain and leucine-rich repeat (NLR)-containing proteins in plants and animals mediate intracellular pathogen sensing. Plant NLRs typically detect strain-specific pathogen effectors and trigger immune responses often linked to localized host cell death. The barley Mla disease resistance locus has undergone extensive functional diversification in the host population and encodes numerous allelic NLRs each detecting a matching isolate-specific avirulence effector (AVRA) of the fungal pathogen Blumeria graminis f. sp. hordei (Bgh). We report here the isolation of Bgh AVRa7, AVRa9, AVRa10, and AVRa22, which encode small secreted proteins recognized by allelic MLA7, MLA9, MLA10, and MLA22 receptors, respectively. These effectors are sequence-unrelated, except for allelic AVRa10 and AVRa22 that are co-maintained in pathogen populations in the form of a balanced polymorphism. Contrary to numerous examples of indirect recognition of bacterial effectors by plant NLRs, co-expression experiments with matching Mla-AVRa pairs indicate direct detection of the sequence-unrelated fungal effectors by MLA receptors.

Non-parent of Origin Expression of Numerous Effector Genes Indicates a Role of Gene Regulation in Host Adaption of the Hybrid Triticale Powdery Mildew Pathogen

Powdery mildew is an important disease of cereals. It is caused by one species, Blumeria graminis, which is divided into formae speciales each of which is highly specialized to one host. Recently, a new form capable of growing on triticale (B.g. triticale) has emerged through hybridization between wheat and rye mildews (B.g. tritici and B.g. secalis, respectively). In this work, we used RNA sequencing to study the molecular basis of host adaptation in B.g. triticale. We analyzed gene expression in three B.g. tritici isolates, two B.g. secalis isolates and two B.g. triticale isolates and identified a core set of putative effector genes that are highly expressed in all formae speciales. We also found that the genes differentially expressed between isolates of the same form as well as between different formae speciales were enriched in putative effectors. Their coding genes belong to several families including some which contain known members of mildew avirulence (Avr) and suppressor (Svr) genes. Based on these findings we propose that effectors play an important role in host adaptation that is mechanistically based on Avr-Resistance gene-Svr interactions. We also found that gene expression in the B.g. triticale hybrid is mostly conserved with the parent-of-origin, but some genes inherited from B.g. tritici showed a B.g. secalis-like expression. Finally, we identified 11 unambiguous cases of putative effector genes with hybrid-specific, non-parent of origin gene expression, and we propose that they are possible determinants of host specialization in triticale mildew. These data suggest that altered expression of multiple effector genes, in particular Avr and Svr related factors, might play a role in mildew host adaptation based on hybridization.

Assessment of imatinib as first-line treatment of chronic myeloid leukemia: 10-year survival results of the randomized CML study IV and impact of non-CML determinants

Chronic myeloid leukemia (CML)-study IV was designed to explore whether treatment with imatinib (IM) at 400 mg/day (n=400) could be optimized by doubling the dose (n=420), adding interferon (IFN) (n=430) or cytarabine (n=158) or using IM after IFN-failure (n=128). From July 2002 to March 2012, 1551 newly diagnosed patients in chronic phase were randomized into a 5-arm study. The study was powered to detect a survival difference of 5% at 5 years. After a median observation time of 9.5 years, 10-year overall survival was 82%, 10-year progression-free survival was 80% and 10-year relative survival was 92%. Survival between IM400 mg and any experimental arm was not different. In a multivariate analysis, risk group, major-route chromosomal aberrations, comorbidities, smoking and treatment center (academic vs other) influenced survival significantly, but not any form of treatment optimization. Patients reaching the molecular response milestones at 3, 6 and 12 months had a significant survival advantage. For responders, monotherapy with IM400 mg provides a close to normal life expectancy independent of the time to response. Survival is more determined by patients' and disease factors than by initial treatment selection. Although improvements are also needed for refractory disease, more life-time can currently be gained by carefully addressing non-CML determinants of survival.

The Impact of Steroidal Glycoalkaloids on the Physiology of Phytophthora infestans, the Causative Agent of Potato Late Blight

Steroidal glycoalkaloids (SGAs) are plant secondary metabolites known to be toxic to animals and humans and that have putative roles in defense against pests. The proposed mechanisms of SGA toxicity are sterol-mediated disruption of membranes and inhibition of cholinesterase activity in neurons. It has been suggested that phytopathogenic microorganisms can overcome SGA toxicity by enzymatic deglycosylation of SGAs. Here, we have explored SGA-mediated toxicity toward the invasive oomycete Phytophthora infestans, the causative agent of the late blight disease in potato and tomato, as well as the potential for SGA deglycosylation by this species. Our growth studies indicate that solanidine, the nonglycosylated precursor of the potato SGAs α-chaconine and α-solanine, has a greater physiological impact than its glycosylated forms. All of these compounds were incorporated into the mycelium, but only solanidine could strongly inhibit the growth of P. infestans in liquid culture. Genes encoding several glycoside hydrolases with potential activity on SGAs were identified in the genome of P. infestans and were shown to be expressed. However, we found no indication that deglycosylation of SGAs takes place. We present additional evidence for apparent host-specific adaptation to potato SGAs and assess all results in terms of future pathogen management strategies.

Development and evaluation of a secondary reference panel for BCR-ABL1 quantification on the International Scale

Molecular monitoring of chronic myeloid leukemia patients using robust BCR-ABL1 tests standardized to the International Scale (IS) is key to proper disease management, especially when treatment cessation is considered. Most laboratories currently use a time-consuming sample exchange process with reference laboratories for IS calibration. A World Health Organization (WHO) BCR-ABL1 reference panel was developed (MR¹–MR⁴), but access to the material is limited. In this study, we describe the development of the first cell-based secondary reference panel that is traceable to and faithfully replicates the WHO panel, with an additional MR^4.5 level. The secondary panel was calibrated to IS using digital PCR with ABL1, BCR and GUSB as reference genes and evaluated by 44 laboratories worldwide. Interestingly, we found that >40% of BCR-ABL1 assays showed signs of inadequate optimization such as poor linearity and suboptimal PCR efficiency. Nonetheless, when optimized sample inputs were used, >60% demonstrated satisfactory IS accuracy, precision and/or MR^4.5 sensitivity, and 58% obtained IS conversion factors from the secondary reference concordant with their current values. Correlation analysis indicated no significant alterations in %BCR-ABL1 results caused by different assay configurations. More assays achieved good precision and/or sensitivity than IS accuracy, indicating the need for better IS calibration mechanisms.

Secondary malignancies in chronic myeloid leukemia patients after imatinib-based treatment: long-term observation in CML Study IV

Treatment of chronic myeloid leukemia (CML) has been profoundly improved by the introduction of tyrosine kinase inhibitors (TKIs). Long-term survival with imatinib is excellent with a 8-year survival rate of ∼88%. Long-term toxicity of TKI treatment, especially carcinogenicity, has become a concern. We analyzed data of the CML study IV for the development of secondary malignancies. In total, 67 secondary malignancies were found in 64 of 1525 CML patients in chronic phase treated with TKI (n=61) and interferon-α only (n=3). The most common malignancies (n⩾4) were prostate, colorectal and lung cancer, non-Hodgkin's lymphoma (NHL), malignant melanoma, non-melanoma skin tumors and breast cancer. The standardized incidence ratio (SIR) for all malignancies excluding non-melanoma skin tumors was 0.88 (95% confidence interval (0.63-1.20)) for men and 1.06 (95% CI 0.69-1.55) for women. SIRs were between 0.49 (95% CI 0.13-1.34) for colorectal cancer in men and 4.29 (95% CI 1.09-11.66) for NHL in women. The SIR for NHL was significantly increased for men and women. An increase in the incidence of secondary malignancies could not be ascertained. The increased SIR for NHL has to be considered and long-term follow-up of CML patients is warranted, as the rate of secondary malignancies may increase over time.

Avirulence Genes in Cereal Powdery Mildews: The Gene-for-Gene Hypothesis 2.0

The gene-for-gene hypothesis states that for each gene controlling resistance in the host, there is a corresponding, specific gene controlling avirulence in the pathogen. Allelic series of the cereal mildew resistance genes Pm3 and Mla provide an excellent system for genetic and molecular analysis of resistance specificity. Despite this opportunity for molecular research, avirulence genes in mildews remain underexplored. Earlier work in barley powdery mildew (B.g. hordei) has shown that the reaction to some Mla resistance alleles is controlled by multiple genes. Similarly, several genes are involved in the specific interaction of wheat mildew (B.g. tritici) with the Pm3 allelic series. We found that two mildew genes control avirulence on Pm3f: one gene is involved in recognition by the resistance protein as demonstrated by functional studies in wheat and the heterologous host Nicotiana benthamiana. A second gene is a suppressor, and resistance is only observed in mildew genotypes combining the inactive suppressor and the recognized Avr. We propose that such suppressor/avirulence gene combinations provide the basis of specificity in mildews. Depending on the particular gene combinations in a mildew race, different genes will be genetically identified as the "avirulence" gene. Additionally, the observation of two LINE retrotransposon-encoded avirulence genes in B.g. hordei further suggests that the control of avirulence in mildew is more complex than a canonical gene-for-gene interaction. To fully understand the mildew-cereal interactions, more knowledge on avirulence determinants is needed and we propose ways how this can be achieved based on recent advances in the field.

[Elastic Stable Intramedullary Nailing (ESIN) of Metatarsal Fractures]

AIM

In the treatment of metatarsal fractures, the objective is early restoration of the physiological painless function of the foot. While undisplaced metatarsal fractures can be treated non-surgically, displaced fractures are a valid indication for reduction and internal fixation. Whereas plate fixation may lead to soft tissue irritation involving tendon adhesions and scar formation, retrograde percutaneous pinning may harm the intact metatarsophalangeal joint and lead to joint stiffness. We have therefore used the technique of elastic stable intramedullary nailing (ESIN) with titanium elastic nails (TEN) to achieve minimally invasive, antegrade splinting of short metatarsal shaft and neck fractures.

METHOD

Within 7 years, ESIN was performed in 22 patients. The surgical technique is presented and the functional results and complications were retrospectively evaluated using the AOFAS Midfoot Score.

RESULTS

Nineteen patients were analysed after an average follow-up of 25.6 ± 21.3 months (range: 3-72 months). The mean AOFAS score was 93.9 ± 10.4 (range 62-100) points. One case of skin irritation required TEN shortening. Pseudarthrosis, secondary fracture dislocation and nail breakage were not observed. After TEN removal 13.4 ± 12.9 (range: 5-52) weeks after implantation, no refracture occurred.

CONCLUSION

Antegrade, minimally invasive, elastic stable intramedullary nailing of short metatarsal shaft and neck fractures using titanium nails (TEN) is a safe surgical procedure and achieves primary functional stability. It reliably leads to fracture healing and produces good functional results.

[The "Muffplastik"--a Fasciocutaneous Reconstruction Technique in a Case of Extensive Soft Tissue Defect of the Distal Forearm--Historical Technique or Salvage Procedure?]

We present a case of a distant pedicled flap to reconstruct a defect at the distal upper extremity. We used this flap as a salvage procedure to treat a patient in the intensive care unit who was in a reduced general condition with numerous comorbidities that made regional or free microvascular flaps hazardous.

Identification of invasive fungal diseases in immunocompromised patients by combining an Aspergillus specific PCR with a multifungal DNA-microarray from primary clinical samples

The increasing incidence of invasive fungal diseases (IFD), most of all invasive aspergillosis (IA) in immunocompromised patients emphasises the need to improve the diagnostic tools for detection of fungal pathogens. We investigated the diagnostic performance of a multifungal DNA-microarray detecting 15 different fungi [Aspergillus, Candida, Fusarium, Mucor, Rhizopus, Scedosporium and Trichosporon species (spp.)] in addition to an Aspergillus specific polymerase chain reaction (PCR) assay. Biopsies, bronchoalveolar lavage and peripheral blood samples of 133 immunocompromised patients (pts) were investigated by a multifungal DNA-microarray as well as a nested Aspergillus specific PCR assay. Patients had proven (n = 18), probable (n = 29), possible (n = 48) and no IFD (n = 38) and were mostly under antifungal therapy at the time of sampling. The results were compared to culture, histopathology, imaging and serology, respectively. For the non-Aspergillus IFD the microarray analysis yielded in all samples a sensitivity of 64% and a specificity of 80%. Best results for the detection of all IFD were achieved by combining DNA-microarray and Aspergillus specific PCR in biopsy samples (sensitivity 79%; specificity 71%). The molecular assays in combination identify genomic DNA of fungal pathogens and may improve identification of causative pathogens of IFD and help overcoming the diagnostic uncertainty of culture and/or histopathology findings, even during antifungal therapy.

[Bilateral Dislocation Fracture of the Humeral Head (Right AO 11C3.3; Left AO 11A1.3) without Direct Trauma Due to First Clinical Manifestation of Seizure - a Case Report and Review of the Literature]

The incidence of fractures among epileptics is frequent and mostly occurs by direct trauma due to falls caused by seizures. The risk of fractures is estimated to be 50 % higher in epileptics than in the general population. Most of the fractures affect the proximal femora and the hip joint. Dorsal shoulder dislocations occur frequently in epileptics. If they occur bilaterally, this is pathognomonic for seizuring. Besides this, shoulder dislocation and bilateral dislocation fractures of the humeral head, however, are far more rare even among epileptics but pathognomonic for seizure. In this case report we present a female patient with bilateral dislocation fracture of the humeral head due to first clinical manifestation of a tonic-clonic seizure without direct trauma.

Perioperative management and outcome of fracture treatment in patients with haemophilia without inhibitors

INTRODUCTION

Fractures in persons with haemophilia (PWH) are not uncommon and require an interdisciplinary approach to maintain haemostasis during surgical treatment.

AIM

The aim of this study was to evaluate the perioperative management and outcome in PWH following fracture fixation compared to a matched non-haemophilic control group.

METHODS

A cohort of 44 PWH who underwent 46 surgical fracture fixations was retrospectively compared to 46 non-haemophilic patients (matched-pair controls). Patients were classified according to the fracture localization: (i) proximal upper extremity (PrUEx; n = 7), (ii) distal upper extremity (DiUEx; n = 12), (iii) proximal lower extremity (PrLEx; n = 13) and (iv) distal lower extremity (DiLEx; n = 14). Both groups were assessed for length of hospital stay, duration of surgery, drainage use and complication rates.

RESULTS

There was no significant difference regarding the duration of the preoperative hospital stay between PWH and controls. Only PWH who were operated at the DiUEx stayed significantly longer in hospital (4.8 ± 3.7 days) than controls (2.2 ± 2.3 days; P = 0.039). Operation time was significantly longer in PWH with fractures treated at the DiLEx (64.9 ± 26.6 min) compared to the controls (49.8 ± 37.9 min; P = 0.035). Neither frequency nor duration of surgical drainage placement differed significantly between the two groups. The overall complication rate in both groups was low without a statistically significant difference.

CONCLUSION

An optimal interdisciplinary perioperative management provided the surgical treatment of fractures in PWH can be performed safely with a low complication rate.

[Impact of Preoperative Knee Stiffness on the Postoperative Outcome after Total Knee Arthroplasty in Patients with Haemophilia]

INTRODUCTION

Total knee arthroplasty (TKA) is an effective treatment option for patients with end-stage haemophilic arthropathy of the knee. However, the procedure is technically challenging, as knee motion is often restricted before the operation and complication rates are then thought to be higher than for patients with a normal range of motion (ROM). There is very limited information on the outcome of TKA in haemophilic patients presenting with stiff knees. The objective of the present study was to retrospectively analyse and compare the clinical results after TKA in haemophiliacs with stiff and non-stiff knees.

PATIENTS AND METHODS

The results of 50 TKA procedures in 41 haemophilic patients were retrospectively evaluated at a mean follow-up of 7.2 ± 4.9 years (range 2-25 years). 20 patients presenting with 23 stiff knees - defined by a preoperative ROM of 50° or less - were compared with 21 patients with 27 non-stiff knees. Knee motion (ROM, flexion, extension), Knee Society Score (KSS/KSS function), pain status (visual analogue scale, VAS), number of bleedings and patient satisfaction were evaluated.

RESULTS

The complication rate was 12 %, including two haematomas, one aseptic loosening, and three periprosthetic infections. The overall mean ROM increased from 58.6 ± 34.2° (range 0-120°) preoperatively to 85.9 ± 23.4 (35-130°) postoperatively (p < 0.005). Mean KSS and KSS function improved from 30.6 ± 11.0 points (range 10-49) and 43.4 ± 9.3 points (range 15-65) to 79.3 ± 9.6 points (range 49-95) and 68.9 ± 11.0 points (45-90), respectively (p < 0.005). The mean VAS score decreased significantly from 7.9 ± 0.8 points (range 6-9) to 1.8 ± 1.1 points (range 0-4; p < 0.005). In comparison to the non-stiff group, patients with stiff knees showed a significantly greater mean improvement in ROM (46.3 ± 21.8° [range - 10-85°] vs. 9.4 ± 16.9° [range - 30-35°]), flexion (32.8 ± 19.6° [range - 10-85°] vs. 5.2 ± 16.2° [range - 40-35°]), and flexion contracture (13.5 ± 9.6° [range 5-30°] vs. 5.9 ± 6.7° [range 5-20°]). Both KSS and KSS function were significantly inferior in stiff knees than with non-stiff knees. Nine patients with knee stiffness who underwent additional v-y quadricepsplasty to lengthen the extensor mechanism developed a mean extensor lag of 7-0° ± 4-8° (range 5-15°). At final follow-up, 37/41 patients were satisfied or very satisfied with the surgical result.

CONCLUSION

TKA in haemophilic patients presenting with haemophilic arthropathy of the knee results in significant improvements in function and reduced pain. Although the ultimate clinical outcome in stiff knees is inferior to that with non-stiff knees, joint replacement surgery can be successfully performed in patients with restricted preoperative range of motion. Vy-quadricepsplasty for to facilitate exposure is associated with the development of a postoperative extensor lag and should therefore be performed restrictively. Patient satisfaction after TKA was equally high in the two groups.

Outcome after total knee arthroplasty in haemophilic patients with stiff knees

INTRODUCTION

Advanced haemophilic arthropathy of the knee is associated with progressive joint stiffness. Results after total knee arthroplasty (TKA) in stiff knees are considered to be inferior compared to those with less restricted preoperative range of motion (ROM). There is only very limited data on the results of primary TKA in haemophilic patients with stiff knees.

AIM

The purpose of this retrospective study was to evaluate the clinical outcome after TKA performed in haemophilic patients with preoperative ROM of 50° or less.

METHODS

Twenty one patients (23 knees) undergoing TKA with stiff knees were retrospectively evaluated. Mean follow-up was 8.3 years (range, 2-25). Clinical assessment included ROM, degree of flexion contracture and complication rate. Functional evaluation and pain status were assessed using the Knee Society's Scoring System (KSS).

RESULTS

Range of motion improved from 26.7° preoperatively to 73.0° postoperatively. Flexion contracture decreased from 21.7° to 8.3°. KSS increased from 22.9 to 72.9 points. Evaluation of pain revealed a decrease from 8.4 points preoperatively to 2.1 points postoperatively. All these differences were statistically significant (P < 0.005). The complication rate was 8.7% including one late periprosthetic infection, and one aseptic implant loosening. Nine patients who required VY-quadricepsplasty for knee exposure developed a mean postoperative extensor lag of 7°.

CONCLUSION

Total knee arthroplasty in haemophilic patients presenting with stiff knees results in significant improvement of function and reduction in pain. Although the clinical outcome is inferior compared to nonstiff knees reported in the literature, joint replacement surgery can be successfully performed in this particular group of patients.

Interferon alpha 2 maintenance therapy may enable high rates of treatment discontinuation in chronic myeloid leukemia

A minority of chronic myeloid leukemia (CML) patients is capable of successfully discontinuing imatinib. Treatment modalities to increase this proportion are currently unknown. Here, we assessed the role of interferon alpha 2a (IFN) on therapy discontinuation in a previously reported cohort of 20 chronic phase CML patients who were treated upfront with IFN alpha plus imatinib followed by IFN monotherapy to maintain cytogenetic or molecular remission (MR) after imatinib discontinuation. After a median follow-up of 7.9 years (range, 5.2-12.2), relapse-free survival was 73% (8/11 patients) and 84% (5/6 patients) for patients who discontinued imatinib in major MR (MMR) and MR4/MR4.5, respectively. Ten patients discontinued IFN after a median of 4.5 years (range, 0.24-9.3). After a median of 2.8 years (range, 0.7-5.1), nine of them remain in ongoing treatment-free remission with MR5 (n=6) and MR4.5 (n=3). The four patients who still administer IFN are in stable MR5, MR4.5, MR4, and MMR, respectively. In conclusion, an IFN/imatinib induction treatment followed by a temporary IFN maintenance therapy may enable a high rate of treatment discontinuation in CML patients in at least MMR when stopping imatinib.

Dual glutathione-S-transferase-θ1 and -μ1 gene deletions determine imatinib failure in chronic myeloid leukemia

Approximately 40% of patients with chronic myeloid leukemia (CML) receiving imatinib fail treatment. There is an increased risk of CML in subjects with (i) deletions of genes encoding glutathione-S-transferase (GST)-θ1 (GSTT1) and -μ1, (GSTM1) and (ii) the GST-π1 (GSTP1) single-nucleotide polymorphism (SNP) Ile105Val (GSTP1*B; rs1695); however, their effects on imatinib treatment outcome are not known. Here, we assess the role of these GSTs in relation to imatinib treatment outcome in 193 CML patients. Deletion of GSTT1 alone, or in combination with deletion of the GSTM1 gene, significantly increased the likelihood of imatinib failure (P = 0.021 and P < 0.001, respectively). The GSTP1*B SNP was not associated with time to imatinib failure. Losses of the GSTT1 and GSTM1 genes are therefore important determinants of imatinib failure in CML. Screening for GSTT1 and GSTM1 gene deletions during diagnosis may identify patients who may be better treated using an alternative therapy.

[Evaluation of radiation exposure of personnel in an orthopaedic and trauma operation theatre using the new real-time dosimetry system "dose aware"]

AIM

There is a positive correlation between operation time and staff exposure to radiation during intraoperative use of C-arm fluoroscopy. Due to harmful effects of exposure to long-term low-dose radiation for both the patient and the operating team it should be kept to a minimum. AIM of this study was to evaluate a novel dosimeter system called Dose Aware® (DA) enabling radiation exposure feedback of the personal in an orthopaedic and trauma operation theatre in real-time.

METHOD

Within a prospective study over a period of four month, DA was applied by the operation team during 104 orthopaedic and trauma operations in which the C-arm fluoroscope was used in 2D-mode. During ten operation techniques, radiation exposure of the surgeon, the first assistant, the theatre nurse and the anaesthesiologist was evaluated.

RESULTS

Seventy-three operations were analysed. The surgeon achieved the highest radiation exposure during dorsolumbar spinal osteosynthesis, kyphoplasty and screw fixation of sacral fractures. The first assistant received a higher radiation exposure compared to the surgeon during plate osteosynthesis of distal radius fractures (157 %), intramedullary nailing of pertrochanteric fractures (143 %) and dorsolumbar spinal osteosynthesis (240 %). During external fixation of ankle fractures (68 %) and screw fixation of sacral fractures (66 %) radiation exposure of the theatre nurse exceeded 50 % of the surgeon's radiation exposure. During plate osteosynthesis of distal radius fractures (157 %) and intramedullary splinting of clavicular fractures (115 %), the anaesthesiologist received a higher radiation exposure than the surgeon.

CONCLUSION

The novel dosimeter system DA provides real-time radiation exposure feedback of the personnel in an orthopaedic and trauma operation theatre for the first time. Data of this study demonstrate that radiation exposure of the personnel depends on the operation type. The first assistant, the theatre nurse and the anaesthesiologist might be exposed to higher radiation doses than the surgeon. DA might help to increase awareness concerning irradiation in an orthopaedic and trauma operation theatre and might enhance staff compliance in using radiation protection techniques.

A certified plasmid reference material for the standardisation of BCR-ABL1 mRNA quantification by real-time quantitative PCR

Serial quantification of BCR–ABL1 mRNA is an important therapeutic indicator in chronic myeloid leukaemia, but there is a substantial variation in results reported by different laboratories. To improve comparability, an internationally accepted plasmid certified reference material (CRM) was developed according to ISO Guide 34:2009. Fragments of BCR–ABL1 (e14a2 mRNA fusion), BCR and GUSB transcripts were amplified and cloned into pUC18 to yield plasmid pIRMM0099. Six different linearised plasmid solutions were produced with the following copy number concentrations, assigned by digital PCR, and expanded uncertainties: 1.08±0.13 × 10⁶, 1.08±0.11 × 10⁵, 1.03±0.10 × 10⁴, 1.02±0.09 × 10³, 1.04±0.10 × 10² and 10.0±1.5 copies/μl. The certification of the material for the number of specific DNA fragments per plasmid, copy number concentration of the plasmid solutions and the assessment of inter-unit heterogeneity and stability were performed according to ISO Guide 35:2006. Two suitability studies performed by 63 BCR–ABL1 testing laboratories demonstrated that this set of 6 plasmid CRMs can help to standardise a number of measured transcripts of e14a2 BCR–ABL1 and three control genes (ABL1, BCR and GUSB). The set of six plasmid CRMs is distributed worldwide by the Institute for Reference Materials and Measurements (Belgium) and its authorised distributors (https://ec.europa.eu/jrc/en/reference-materials/catalogue/; CRM code ERM-AD623a-f).

[Thromboembolic complications 6 months after plate osteosynthesis of a mid-clavicular fracture]

A 32-year-old patient suffered from progredient intermittent claudication of the left arm 6 months after plate fixation of a midshaft clavicular fracture (OTA classification type A). The radiological analysis revealed a subacute stenosis of the left subclavian artery, caused by a granuloma at the tip of a protruding screw, which triggered recurrent emboli and symptoms. Reperfusion was achieved by catheter embolectomy and complete removal of the plate. The case shows that, when performing plate osteosynthesis of clavicular fractures, special consideration has to be given to the length and protrusion of the applied screws. Due to the anatomic proximity not only acute, but also subsequent irritation of the subclavian vessels is possible.

MDR1 expression predicts outcome of Ph+ chronic phase CML patients on second-line nilotinib therapy after imatinib failure

In the face of competing tyrosine kinase inhibitors (TKIs), identification of chronic myeloid leukemia (CML) patients expecting favorable response to second-line treatment is warranted. At the time of imatinib resistance, the investigation of multidrug-resistance protein 1 (MDR1) and BCR-ABL yielded the following results: (i) Patients with high MDR1 transcript levels showed superior response at 48 months as compared with low-level MDR1 patients: major molecular response (MMR) in 41% vs 16% (P=0.014), complete cytogenetic response (CCyR) in 58% vs 39% (P=0.044), and progression-free survival (PFS) in 67% vs 46% (P=0.032). (ii) Patients with BCR-ABL(IS) <28% achieved higher MMR rates (48% vs 21%, P=0.009). (iii) PFS at 48 months was associated with in vitro resistance of BCR-ABL kinase domain mutations: 63% (no mutation) vs 61% (sensitive, intermediately sensitive or unknown IC50 (median inhibitory concentration)) vs 23% (resistant, P=0.01). (iv) Single-nucleotide polymorphisms (SNPs) at positions 1236 and 2677 were associated with higher MDR1 expression in comparison to wild type. (v) Nilotinib was able to impede proliferation of MDR1-overexpressing imatinib-resistant cells. High MDR1 gene expression might identify patients whose mode of imatinib resistance is essentially determined by increased efflux activity of MDR1 and therefore can be overcome by second-line nilotinib treatment.

A phase 2 trial of ponatinib in Philadelphia chromosome-positive leukemias

BACKGROUND

Ponatinib is a potent oral tyrosine kinase inhibitor of unmutated and mutated BCR-ABL, including BCR-ABL with the tyrosine kinase inhibitor-refractory threonine-to-isoleucine mutation at position 315 (T315I). We conducted a phase 2 trial of ponatinib in patients with chronic myeloid leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph-positive ALL).

METHODS

We enrolled 449 heavily pretreated patients who had CML or Ph-positive ALL with resistance to or unacceptable side effects from dasatinib or nilotinib or who had the BCR-ABL T315I mutation. Ponatinib was administered at an initial dose of 45 mg once daily. The median follow-up was 15 months.

RESULTS

Among 267 patients with chronic-phase CML, 56% had a major cytogenetic response (51% of patients with resistance to or unacceptable side effects from dasatinib or nilotinib and 70% of patients with the T315I mutation), 46% had a complete cytogenetic response (40% and 66% in the two subgroups, respectively), and 34% had a major molecular response (27% and 56% in the two subgroups, respectively). Responses were observed regardless of the baseline BCR-ABL kinase domain mutation status and were durable; the estimated rate of a sustained major cytogenetic response of at least 12 months was 91%. No single BCR-ABL mutation conferring resistance to ponatinib was detected. Among 83 patients with accelerated-phase CML, 55% had a major hematologic response and 39% had a major cytogenetic response. Among 62 patients with blast-phase CML, 31% had a major hematologic response and 23% had a major cytogenetic response. Among 32 patients with Ph-positive ALL, 41% had a major hematologic response and 47% had a major cytogenetic response. Common adverse events were thrombocytopenia (in 37% of patients), rash (in 34%), dry skin (in 32%), and abdominal pain (in 22%). Serious arterial thrombotic events were observed in 9% of patients; these events were considered to be treatment-related in 3%. A total of 12% of patients discontinued treatment because of an adverse event.

CONCLUSIONS

Ponatinib had significant antileukemic activity across categories of disease stage and mutation status. (Funded by Ariad Pharmaceuticals and others; PACE ClinicalTrials.gov number, NCT01207440 .).

[Elastic titanium nails for minimally invasive intramedullary splinting of metacarpal fractures]

AIM

The goal in treatment of metacarpal fractures is to restore the normal function of the hand. Although a majority of these fractures can be treated non-operatively, surgery is recommended for displaced fractures and in case of a patient wish for primary stability for practise. A poor clinical outcome is described for metacarpal shortening of more than 5 millimeters and for rotational deformity. Whereas plate osteosynthesis may lead to soft tissue irritation involving tendon adhesions and scar formation, we have used the elastic stable intramedullary nailing [ESIN] technique using titanium elastic nails (TEN) for intramedullary splinting of short metacarpal shaft and neck fractures.

METHOD

Within 5 years, ESIN was performed in 95 patients. The operative technique was evaluated retrospectively concerning its functional results and complications.

RESULTS

Sixty-three patients were analysed after an average follow-up of 14.0 ± 5.2 weeks. The mean DASH-Score was 2.3 ± 3.9 points. We saw one implant out-of-position and three cases of skin irritation affording TEN shortening. Two superficial wound infections were treated conservatively. Pseudarthrosis and nail breakage were not observed. After TEN removal 9 ± 2.4 weeks post implantationem no refracture occurred.

CONCLUSION

Minimally invasive intramedullary stabilisation of short metacarpal shaft and neck fractures with a TEN is a safe surgical technique and achieves primary stability for practise. It reliably leads to fracture healing and produces excellent functional results.

[Basic principles of surgical treatment of bone metastases]

Due to an increased life expectancy and improved oncological treatment, the necessity for surgical treatment of bone metastases has increased as well. Ideally, therapy should concentrate on the improvement of the patient's quality of life while preferably being interdisciplinary. The type and extent of surgical therapy depend on the prognosis, tumor entity, localization of the tumor as well as on the patient's general condition. The main aims of surgical treatment is to reduce pain and preserve or restore function and mobility. After the contribution on spinal metastases in the last volume, this article focusses on metastases of the extremities and the pelvis. Pathologic fractures with an unclear oncological situation should be examined thoroughly before any surgical treatment is performed. In case of doubt, a biopsy should be performed. Depending on the individual prognosis, possible options for extremity surgery are (compound) osteosynthesis and implantation of a tumor endoprosthesis. The latter should be preferred for patients with a favorable prognosis and long life expectancy. To avoid revision surgery, the selected implant should outlast the patient's remaining life expectancy.

Early molecular and cytogenetic response is predictive for long-term progression-free and overall survival in chronic myeloid leukemia (CML)

In the face of competing first-line treatment options for CML, early prediction of prognosis on imatinib is desirable to assure favorable survival or otherwise consider the use of a second-generation tyrosine kinase inhibitor (TKI). A total of 1303 newly diagnosed imatinib-treated patients (pts) were investigated to correlate molecular and cytogenetic response at 3 and 6 months with progression-free and overall survival (PFS, OS). The persistence of BCR-ABL transcript levels >10% according to the international scale (BCR-ABL(IS)) at 3 months separated a high-risk group (28% of pts; 5-year OS: 87%) from a group with >1-10% BCR-ABL(IS) (41% of pts; 5-year OS: 94%; P=0.012) and from a group with ≤1% BCR-ABL(IS) (31% of pts; 5-year OS: 97%; P=0.004). Cytogenetics identified high-risk pts by >35% Philadelphia chromosome-positive metaphases (Ph+, 27% of pts; 5-year OS: 87%) compared with ≤35% Ph+ (73% of pts; 5-year OS: 95%; P=0.036). At 6 months, >1% BCR-ABL(IS) (37% of pts; 5-year OS: 89%) was associated with inferior survival compared with ≤1% (63% of pts; 5-year OS: 97%; P<0.001) and correspondingly >0% Ph+ (34% of pts; 5-year OS: 91%) compared with 0% Ph+ (66% of pts; 5-year OS: 97%; P=0.015). Treatment optimization is recommended for pts missing these landmarks.

[Replacement of the comminuted radial head fracture by a bipolar radial head prosthesis]

OBJECTIVE

Radial head arthroplasty as a treatment of non-reconstructable, comminuted fractures of the radial head in order to achieve elbow stability and to prevent secondary complications, such as valgus elbow instability and radius proximalization.

INDICATIONS

In acute trauma, a radial head fracture not suitable for internal fixation without (Mason grade III) and with (Mason grade IV) concomitant destabilizing injury, Essex-Lopresti injury, sequelae following radial head resection (e.g., elbow instability or wrist pain), failed reconstruction of the radial head, and tumor-associated radial head or neck resection.

CONTRAINDICATIONS

General medical contraindications for surgical intervention, cobalt-chromium allergy, and osteoporosis of the proximal radius.

SURGICAL TECHNIQUE

In supine position, a lateral or posterolateral approach at the elbow was used. The annular ligament was exposed and the radial neck identified just above the bicipital tuberosity. In pronation of the forearm in order to protect the radial nerve, the medullary canal was prepared using rasps. The size of the implant was determined using trial stems. A distance of 0.5 mm between the head of the prosthesis and the capitulum humeri was recommended. After using a small bone plug, the prosthesis was cemented with respect to the anatomical radial curvature. After reconstruction of the annular ligament, the stability of the elbow was verified. In case of instability, the medial collateral ligament was reconstructed and afterwards the wound closed.

POSTOPERATIVE MANAGEMENT

Early mobilization begins the day after surgery. In case of additional injuries, the elbow was supported by an above-elbow cast for 3-4 weeks. To prevent heterotopic ossification, nonsteroidal antiinflammatory drugs were used for up to 4 weeks with gastric protection.

RESULTS

A total of 13 patients with 15 radial head prosthesis were analyzed at a mean follow-up of 29.5±20.8 months. In all patients, the elbow was stable. Subjectively, good and excellent results were found with one exception. Compared to the pretrauma status, the subjective rate was 78±12%. Based on the Radin and Riseborough score, 6 of the results were good and 9 were fair. According to the Broberg and Morrey score, 1 result was very good, 8 were good, and 6 were fair. The mean DASH score was 9.9±9.7 points. Two temporary nerve lesions were observed. Five patients were diagnosed with heterotopic ossification stage I, while 2 patients were classified with stage II on the Brooker scale.

Evaluation of a new computer-assisted surgical planning and navigation system based on two-dimensional fluoroscopy for insertion of a proximal femoral nail: an experimental study

Pertrochanteric femoral fractures are common and intramedullary nailing is an accepted method for their surgical treatment. Accurate placement of the implant is essential to ensure fixation. The conventional technique can require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based on two-dimensional fluoroscopy for guide wire placement in the femoral neck has been developed, in order to perform intramedullary pertrochanteric fracture fixation using the proximal femoral nail (PFNA). The planning process was supported by a 'zero-dose C-arm navigation' system. The PFNA was inserted into 12, intact, femoral sawbones guided by the computer-based navigation, and into 12, intact, femoral sawbones using a conventional fluoroscopic-assisted technique. Guide wire and subsequent blade placement in the femoral neck was evaluated. The computer-assisted technique achieved a significant decrease in the number of required fluoroscopic images and in the number of guide wire passes. The obtained average blade placement accuracy in the femoral neck was equivalent to the conventional technique. The operation time was significantly longer in the navigation-assisted group. The addition of computer-assisted planning and surgical guidance to the intramedullary nailing of pertrochanteric femoral fractures offers a number of clinical benefits based on the results of this sawbone study. Further studies including fractured sawbones and cadaver models with extension of the navigation process to all steps of PFNA introduction and with the goal of reducing operation time are indispensable before integration of this navigation system into clinical practice.

Evaluation of a fluoroscopy-based navigation system enabling a virtual radiation-free preview of X-ray images for placement of cannulated hip screws. A cadaver study

Accurate placement of cannulated screws is essential to ensure fixation of medial femoral neck fractures. The conventional technique may require multiple guide wire passes, and relies heavily on fluoroscopy. A computer-assisted planning and navigation system based on 2D fluoroscopy for guide wire placement in the femoral neck has been developed to improve screw placement. The planning process was supported by a tool that enables a virtual radiation-free preview of X-ray images. This is called "zero-dose C-arm navigation". For the evaluation of the system, six formalin-fixed cadaveric full-body specimens (12 femurs) were used. The evaluation demonstrated the feasibility of fluoroscopically navigated guide wire and implant placement. Use of the novel system resulted in a significant reduction in the number of fluoroscopic images and drilling attempts while achieving optimized accuracy by attaining better screw parallelism and enlarged neck-width coverage. Operation time was significantly longer in the navigation assisted group. The system has yielded promising initial results; however, additional studies using fractured bone models and with extension of the navigation process to track two bone fragments must be performed before integration of this navigation system into the clinical workflow is possible, and these studies should focus on reducing the operation time.

[Evaluation of a 2D fluoroscopy-based navigation system for insertion of the dynamic hip screw (DHS): an experimental study]

PURPOSE

Dynamic hip screw (DHS) insertion for the fixation of lateral femoral neck fractures is an accepted surgical treatment method. A computer-assisted planning and navigation system based on 2D fluoroscopy has been developed for guidewire insertion in order to perform screw placement. The image acquisition process was supported by a radiation-saving procedure called "zero-dose C-arm navigation". The aim of this study was to evaluate this new system.

MATERIALS AND METHODS

In the context of a sawbone study, we inserted dynamic hip screws. The procedure was performed under navigation control and in the conventional technique in 12 sawbones. Both procedures were performed in an open and closed technique.

RESULTS

The computer-assisted technique significantly reduced the number of intraoperative fluoroscopic images (open technique: -8.1 ± 0.5; p < 0.001 - closed technique: -12.3 ± 3.7; p < 0.001) and the number of guidewire passes (open technique: -1.3 ± 1.2; p < 0.05 - closed technique: -1.5 ± 1.2; p < 0,05). There was no difference with respect to precision in both groups. The operation time was significantly longer in the navigation-assisted groups (open technique: + 14.6 ± 5.4 min; p < 0.001 - closed technique: + 13 ± 3 min; p < 0.001).

CONCLUSION

The addition of computer-assisted planning and surgical guidance supported by "zero-dose C-arm navigation" may be useful for the fixation of lateral femoral neck fractures by the DHS as it reduces the amount of fluoroscopic images and requires fewer drill tracks. Further studies with the goal of reducing the operation time are necessary.

[Evaluation of a 2D fluoroscopy-based navigation system for insertion of femoral neck screws. An experimental study]

INTRODUCTION

The aim of this study was the evaluation of a new computer-assisted planning and navigation system based on 2D-fluoroscopy for guidewire insertion in order to perform cannulated screw placement into the femoral neck. The image acquisition process was supported by a radiation-saving procedure called Zero-dose C-arm navigation.

MATERIAL AND METHODS

In the context of a sawbone study, we performed insertion of 3 cannulated screws positioned under navigation control as well as using the conventional technique in 12 sawbones. Both procedures were performed using open and closed techniques.

RESULTS

The computer-assisted technique significantly reduced the amount of intraoperative fluoroscopic images (open technique: -14±3 images, closed technique: -29.4±6 images). Drilling attempts were reduced in the computer-assisted groups (open technique: -1.2±1 attempts, closed technique: -1.7±1.5 attempts) and the femoral neck area covered by the screws was greater in the navigation-assisted groups (open technique: +32.1±16.3 mm(2), closed technique: +32.6±14.9 mm(2)), There was no difference concerning parallelism of the screws or perforation of femoral neck or head. The operation time was significantly longer in the navigation-assisted groups (open technique: +24.2±2.1 min, closed technique: +22.8±5.8 min).

CONCLUSION

The addition of computer-assisted planning and surgical guidance supported by Zero-dose C-arm navigation can be useful for the fixation of medial femoral neck fractures with cannulated screws. Further studies with the goal of reducing the operation time are indispensable before integrating this navigation system into the clinical workflow.

[Clinical results after replacement of comminuted radial head fractures (Mason III and IV) by the bipolar radial head prosthesis of Judet]

AIM

Long-term results after resection of comminuted fractures of the radial head (Mason III and IV) may lead to valgus elbow instability, radius proximalisation and rotatory instability. Radial head replacement has been used to prevent and treat these complications. The aim of this study was to define the value of the bipolar radial head prosthesis of Judet for treating comminuted fractures of the radial head.

METHOD

Over a 5-year period, 14 radial head prosthesis were implanted in 12 patients. Retrospectively, we studied the clinical and radiological results.

RESULTS

Eleven patients with thirteen implants were analysed at a mean follow-up of 33.4 +/- 20.4 months. In all patients, the elbow was stable. Subjectively, we found good and excellent results with one exception. Compared to the pre-trauma status, the subjective rate was 78 +/- 12 %. According to the score of Radin and Riseborough, five of the results were found to be good and eight to be fair. According to the Broberg and Morrey score, one result was found to be very good, seven to be good and five to be fair. The mean DASH score was 10.2 +/- 10.1 points. Two temporary nerve lesions were observed.

CONCLUSION

In comminuted fractures of the radial head (Mason III and IV), bipolar radial head replacement with the Judet prosthesis leads subjectively to very good and good and functionally to good and fair results on the medium-term view. Joint stability is achieved and secondary complications like valgus elbow deformity and proximal radial migration are prevented. Patients must be informed about the possibility of temporary nerve lesions, heterotopic ossification causing limitation of motion and the lack of long-term results.

[Parkinson's disease influences the perioperative risk profile in trauma patients]

AIM

Parkinson's disease (PD) is one of the most common degenerative diseases of the central nervous system affecting elderly patients with increasing demographic prevalence. The aim of this study was to define the perioperative risk profile in trauma patients suffering from Parkinson's disease in order to improve treatment options in these patients.

METHOD

Over a period of 13 years, 16 patients suffering from Parkinson's disease treated in the department of trauma surgery were retrospectively compared using matched-pair analysis with 16 controls not affected by PD. Both groups of patients were assessed regarding morbidity, length of treatment and rehabilitation.

RESULTS

Trauma patients suffering from Parkinson's disease showed an increase in morbidity risk. Postoperative falls occurred significantly, infections of the urinary tract and pneumonia tendentiously more often in PD patients. Postoperative stay and length of treatment were significantly longer in patients with PD. These patients also tended to stay longer preoperatively and remained longer in intensive care. PD patients required on-ward rehabilitation significantly more often.

CONCLUSION

Concomitant Parkinson's disease is a significant factor of perioperative morbidity in trauma patients. Perioperative morbidity in PD patients may be influenced by early diagnostic and therapeutic measures.

[Elastic titanium nails in minimally invasive osteosynthesis for mid-clavicular fractures]

BACKGROUND

In up to 31% of cases, conservative treatment of mid-clavicular fractures leads to unsatisfactory results. The aim of this study was to define the value of minimally invasive elastic stable intramedullary nailing (ESIN) of mid-clavicular fractures with titanium elastic nails.

MATERIAL AND METHODS

Within 5 years, ESIN was performed in 45 patients. We studied the functional results and complications.

RESULTS

Retrospectively we analysed the results of all patients at a mean follow-up of 24.7+/-2.4 months. Iatrogenic perforation of the lateral cortex occurred twice and medial migration in eight patients. Superficial skin infection developed in one. Nail breakage after fracture healing was observed twice. Twelve patients sustained clavicular shortening of > or =5 mm in relation to the intact contralateral side. After 6 months the mean constant score was 94.3+/-2 points, and the mean DASH score was 5.4+/-2.2 points.

CONCLUSION

Intramedullary stabilisation of mid-clavicular fractures with titanium elastic nails is a minimally invasive technique with good functional results. Patients must be informed about the possibility of open reduction in about half of the cases as well as shoulder asymmetry, migration of the nail, and iatrogenic nerve and vessel injury.

Recurrent finding of the FIP1L1-PDGFRA fusion gene in eosinophilia-associated acute myeloid leukemia and lymphoblastic T-cell lymphoma

The FIP1L1-PDGFRA fusion gene has been described in patients with eosinophilia-associated myeloproliferative disorders (Eos-MPD). Here, we report on seven FIP1L1-PDGFRA-positive patients who presented with acute myeloid leukemia (AML, n=5) or lymphoblastic T-cell non-Hodgkin-lymphoma (n=2) in conjunction with AML or Eos-MPD. All patients were male, the median age was 58 years (range, 40-66). AML patients were negative for common mutations of FLT3, NRAS, NPM1, KIT, MLL and JAK2; one patient revealed a splice mutation of RUNX1 exon 7. Patients were treated with imatinib (100 mg, n=5; 400 mg, n=2) either as monotherapy (n=2), as maintenance treatment after intensive chemotherapy (n=3) or in overt relapse 43 and 72 months, respectively, after primary diagnosis and treatment of FIP1L1-PDGFRA-positive disease (n=2). All patients are alive, disease-free and in complete hematologic and complete molecular remission after a median time of 20 months (range, 9-36) on imatinib. The median time to achievement of complete molecular remission was 6 months (range, 1-14). We conclude that all eosinophilia-associated hematological malignancies should be screened for the presence of the FIP1L1-PDGFRA fusion gene as they are excellent candidates for treatment with tyrosine kinase inhibitors even if they present with an aggressive phenotype such as AML.

Gene expression signature of primary imatinib-resistant chronic myeloid leukemia patients

Although the selective tyrosine kinase inhibitor imatinib is successfully used in the treatment of chronic myeloid leukemia (CML), inherent mechanisms confer primary resistance to leukemic patients. In order to search for potentially useful genes in predicting cytogenetic response, a retrospective gene expression study was performed. Leukocyte RNA isolated before imatinib from interferon-alpha-pretreated chronic phase CML patients (n=34) with or without major cytogenetic remission (< or =35% Philadelphia (Ph)+ metaphases) during the first year of treatment was comparatively analyzed using Affymetrix U133A chips. Using support vector machines for gene classification, an outcome-specific gene expression signature consisting of 128 genes was identified. Comparative expression data of specific genes point to changes in apoptosis (e.g. casp9, tumor necrosis factor receptor-associated protein 1, hras), DNA repair (msh3, ddb2), oxidative stress protection (glutathione synthetase, paraoxonase 2, vanin 1) and centrosomes (inhibitor of differentiation-1) within primary resistant patients. Independent statistical approaches and quantitative real-time reverse transcriptase-polymerase chain reaction studies support the clinical relevance of gene profiling. In conclusion, this study establishes a candidate predictor of imatinib resistance in interferon-alpha-pretreated CML patients to be subjected to future investigation in a larger independent patient cohort. The resulting expression signature point to involvement of BCR-ABL-independent mechanisms of resistance.