Cancellous allogenic and autologous bone grafting ensure comparable tunnel filling results in two-staged revision ACL surgery.

OBJECTIVES: Patients with recurrent instability after anterior cruciate ligament (ACL) reconstruction often present with enlarged or misplaced tunnels and bone grafting is required prior to the actual revision reconstruction. Autologous bone grafting features limited quantity and donor site morbidity. These problems may be eliminated utilizing cancellous bone allografts, but their efficiency and reliability have not been investigated systematically. The aim of the present study was to compare tunnel filling rates attained by utilizing either allogenic or autologous cancellous bone grafts. MATERIALS AND METHODS: A total of 103 consecutive patients were enrolled retrospectively. All patients suffered from recurrent instability and underwent either allogenic or autologous cancellous bone grafting. Computed tomography (CT) was carried out before and after the bone grafting procedure. Based on preoperative CT scans, positioning and maximum diameter of the femoral and tibial tunnels were determined. Tunnel filling rates were calculated as a ratio of pre- and postoperative tunnel volumes. Primary outcome was the tibial tunnel filling rate. Femoral filling rates and density of the grafted bone were assessed secondarily. RESULTS: Preoperative CT scans revealed no significant differences between the two groups regarding distribution of misplacement and widening of the femoral or tibial tunnel. Postoperative CT scans were conducted after an interval of 5.2 months. Tunnel filling rates of 74.5% (± 14.3) femoral and 85.3% (± 10.3) tibial were achieved in the allogenic compared to 74.3% (± 15.9) femoral and 84.9% (± 9.4) tibial in the autologous group. With p values of 0.85 at the femur and 0.83 at the tibia, there were no significant differences between the groups. The density of the grafted bone revealed significantly higher values in the allogenic group. CONCLUSIONS: Utilizing cancellous bone allografts in two-staged revision ACL surgery provides for sufficient and reproducible filling of enlarged or misplaced tunnels. The filling rates are comparable to those achieved with autologous bone grafting. Advantages of allografts are the unrestricted quantity and the absence of any harvesting procedure.

Intraoperative fluoroscopy during MPFL reconstruction improves the accuracy of the femoral tunnel position.

PURPOSE: Reconstruction of the medial patellofemoral ligament (MPFL) has been established as standard of care for patellofemoral instability. An anatomic femoral tunnel position has been shown to be a prerequisite for restoration of patellofemoral stability and biomechanics. However, the incidence of malpositioning of the femoral tunnel during MPFL reconstruction continues to be notable. Palpation of anatomic landmarks and intraoperative fluoroscopy are the two primary techniques for tunnel placement. The aim of this study was to compare the accuracy of these two methods for femoral tunnel placement. METHODS: From 2016 to 2017, 64 consecutive patients undergoing MPFL reconstruction for patelllofemoral instability were prospectively enrolled. During surgery, the presumed femoral MPFL insertion was identified by both palpation of anatomic landmarks and using fluoroscopy, both of these points were separately documented on true lateral radiographs. They were then analysed and deviations from the Schoettle's Point were measured as anterior-posterior and proximal-distal deviations. A tunnel position within a radius of 7 mm around the Schoettle's Point was designated as an "accurate tunnel position". RESULTS: Compared to the method of palpation, fluoroscopy led to significantly more anatomic femoral tunnel positoning (p < 0.0001). The mean proximal-distal and anterior-posterior distances between the femoral insertion site identified by palpation and the Schoettle's Point were 5.7 ± 4.5 mm (0.3-20.3 mm) and 4.1 ± 3.7 mm (0.1-20.3 mm), respectively, versus 1.7 ± 0.9 mm (0.1-3.6 mm) and 1.8 ± 1.3 mm (0.1-4.8 mm) for fluoroscopy, respectively. Using fluoroscopy, all femoral insertion sites were identified within a 7 mm radius around the centre of the Schoettle's Point. In contrast, only 52% (33) of femoral insertion sites identified by palpation were within this radius. These data were independent of patients' age, gender and BMI. No improvement in accuracy of femoral tunnel positions was detected over time. CONCLUSIONS: The main finding of this study was that, compared to the method of palpation of anatomic landmarks, the use of intraoperative fluoroscopy in MPFL reconstruction leads to more accurate femoral tunnel positioning. Based on these results, the use of intraoperative fluoroscopy has to be recommended for femoral tunnel placement in daily surgical practice to minimize the incidence of malpositioning and to restore native patellofemoral biomechanics. STUDY DESIGN: Level III Case-control study.

The Impact of Pinless Navigation in Conventionally Aligned Total Knee Arthroplasty.

BACKGROUND: Restoration of the mechanical axis is a main objective in total knee replacement (TKR). Aim of this study was to analyse the verification tool of a pinless navigation system in conventional TKR (cTKR). METHODS: In a prospective study, 147 TKR were performed by conventional technique. Using the "pinless verification" mode of a smartphone based navigation system, the cutting block position and final resection plane for distal femur and proximal tibial resection were measured. If necessary, the block position or resection level were optimized, corrections were protocolled. Postoperatively, standardized radiographs were performed. RESULTS: In 65.3%, intraoperative measurements changed the surgical procedure (corrections: 20.4% femoral, 25.9% tibial, 19% both). The additional time for surgery compared to cTKR averaged 6 minutes (79 ± 15 versus 73 ± 17 minutes). Using navigation data, the final femoral and tibial axes were in 93% within a range of ±2°. A mean difference of 1.4° and 1.6° could be shown between the final measurement of the navigation system and the postoperative mLDFA and mMPTA. CONCLUSION: Intraoperative pinless navigation has impact on the surgical procedure in the majority of cTKR. It represents a less time-consuming tool to improve implant position while maintaining the routine of conventional technique.

Aggressiveness of Colletotrichum sublineola Strains from Sorghum bicolor and S. halepense to Sweet Sorghum Variety Sugar Drip, and Their Impact on Yield.

Sweet sorghum (Sorghum bicolor) has been grown in the southeastern United States for more than 150 years on a relatively limited scale, primarily for forage and for the production of table syrup. However, interest in the crop has increased recently due to its potential as a feedstock for biofuels. Colletotrichum sublineola is the causal agent of anthracnose on cultivated sorghum and on the wild sorghum relative Johnsongrass (S. halepense). Anthracnose is an important disease of grain sorghum worldwide, but little is known about its impact on sweet sorghum in the U.S. The aggressiveness of four C. sublineola isolates collected from sweet and grain sorghum and from Johnsongrass at various locations across Kentucky was measured as disease incidence and severity on the susceptible heirloom sweet sorghum inbred Sugar Drip in inoculated field trials. The isolate from sweet sorghum was the most aggressive, while the two Johnsongrass isolates caused only minimal disease symptoms. Disease incidences of up to 99%, and severities of up to 16.7% of leaf area affected, had no negative effect on the yield of biomass, grain, juice, or Brix. Removal of sorghum seed heads increased Brix in the stalks and leaves, but did not affect susceptibility to anthracnose. The same group of fungal isolates was evaluated for aggressiveness in greenhouse assays on juvenile plants, and in the laboratory on seedlings and detached leaf sheaths. These protocols will be useful for prescreening sorghum germplasm for new sources of resistance or for characterizing the aggressiveness of new fungal isolates.

Demonstration of an SOA-assisted open metro-access infrastructure for heterogeneous services.

An open converged metro-access network approach allows for sharing optical layer resources like fibers and optical spectrum among different services and operators. We demonstrated experimentally the feasibility of such a concept by the simultaneous operation of multiple services showing different modulation formats and multiplexing techniques. Flexible access nodes are implemented including semiconductor optical amplifiers to create a transparent and reconfigurable optical ring network. The impact of cascaded optical amplifiers on the signal quality is studied along the ring. In addition, the influence of high power rival signals in the same waveband and in the same fiber is analyzed.

Renal artery revascularization after unsuccessful percutaneous therapy: a single centre experience.

PURPOSE: This retrospective review describes the long time effect of surgical revascularization after unsuccessful early or mid-term failure of percutaneous transluminal renal angioplasty (PTRA). METHODS: From January 1995 to January 2005, 60 out of 696 patients operated due to renal artery occlusive disease (17 fibromuscular dyplasia (FMD): mean age, 33.4 years; 43 atherosclerotic disease (ASD): mean age, 62.46 years) after unsuccessful PTRA underwent surgical revascularization for renal artery stenosis at our institution. The mean duration from failed PTRA to operation was 1.74 years. Out of the 68 renal arteries, 44 were pretreated with angioplasty alone (19, FMD; 25, ASD), and 24 were treated with PTRA and stent (all ASD). Operative management, response of renal function and hypertension as well as survival were compared to the literature. RESULTS: Fifty-nine per cent (n = 40) of the renal arteries were treated by transaortic thrombendarterectomy, 37% (n = 25) by bypass. Thirty-day and in-hospital mortality was 0% in all pretreated patients; after a mean of 4.16 years, it was 16.6% (only atherosclerotic). There was a significant decrease in systolic blood pressure values for all patients early after surgery as well as in follow-up. Creatinine remained stable in the patients with FMD, and there was an insignificant increase in creatinine level in the atherosclerotic patients. Hypertension was improved or healed in 32.5% of all pretreated patients, in cases with FMD in 54%, in atherosclerotic cases in 22.2%. Re-stenoses occurred in 26% of cases with FMD and in 18% of patients with atherosclerotic RAS. CONCLUSION: Surgical renal artery revascularization after failed PTRA is feasible and safe and systolic blood pressure can be lowered. The higher rate in re-stenoses in both the literature as well as in our own experience may be explained by the alterations in the renal artery after interventional treatment.

[Development of neointimal matrix after incorporation of modern alloplastic prostheses: comparison between ePTFE and Dacron]. / Entwicklung neointimaler Matrix nach Einheilen moderner Prothesen: Vergleich zwischen ePTFE und Dacron.

BACKGROUND: In the therapy for peripheral arterial occlusive disease there remain inadequacies in the use of alloplastic material concerning thrombogenicity and biological compliance. In the 1960s, Sparks tried to combine the advantages of alloplastic prostheses with those of autologous reconstructions by using incorporated prostheses. No extensive myointimal hyperplasia was noted, but besides infections aneurysmatic dilatation were limiting factors in clinical practice. MATERIAL AND METHODS: The incorporation of modern alloplastic prostheses without connection to circulation concerning the thickness of neointima as well as the percentage of smooth muscle cells was examined in a dog model. RESULTS: The thickness of the neointima increased significantly in Dacron grafts with a peak on day 70 (p = 0.022), additionally a significantly greater percentage of smooth muscle cells was noted in Dacron grafts after 44 and 58 days (p = 0.008, p = 0.036). CONCLUSION: Due to the decreased thickness of the incorporating matrix as well as the lower percentage of smooth muscle cells, PTFE grafts should be preferred for peripheral arterial revascularisation.

The incidence of iliac aneurysms in patients with abdominal aortic aneurysms: comparison of four centers in Europe and the USA.

BACKGROUND: The purpose of this study was to compare the anatomy of the aortoiliac vessels in patients scheduled for infrarenal abdominal aortic aneurysm (AAA) repair in four different countries. MATERIAL AND METHODS: Consecutives series of 100 preoperative CT-scans were evaluated at each center. Diameters of the suprarenal aorta, maximal diameter of the aneurysm, right and left common and external iliac artery as well as the hypogastric arteries were recorded and compared between each center. RESULTS: Configuration of the AAA above bifurcation was similar at each center. The dimensions of the aortic bifurcation and the common iliac arteries were different among the centers. Common iliac arteries with diameters over 25 mm were significantly more common at center 1 (p < 0.001, p = 0.002 and p < 0.001). Among centers 2, 3 and 4 there was no significant difference in common iliac diameters. CONCLUSIONS: Configuration of the iliac arteries in AAA was significantly different for Swiss patients compared to American, Austrian and German patients. Reasons for these differences are unclear, epidemiological or genetic factors may be responsible.

[Interdisciplinary operative procedure-pelvis and abdomen]. / Operative Interdisziplinarität-Becken und Abdomen.

Surgery for tumors in the abdomen, retroperitoneum, and pelvis requires technical skills and expertise sometimes beyond the capability of a single surgeon. This holds especially true if curative tumor resection involves replacement of arteries and veins, which needs careful planning to avoid long periods of ischemia, and the selection and provision of vascular substitutes according to anatomical position, postsurgical therapy, and adjuncts to avoid thrombosis and infection of vascular grafts. Since the works of Fortner, the value of close collaboration between general and vascular surgeons has been demonstrated, but many of the former even today continue to attempt the operation alone, although the result is not always a masterpiece. The authors refer to their experience in major tumor surgery in either the single management of vascular complications or collaboration. The potential value of close collaboration is presented by negative examples, and a plea is made for a less "eminence"-based management of these sometimes difficult cases, which is based on vast positive experience with vascular diseases of the aorta and the visceral and iliac arteries and veins, including safety measures and adjuncts.

Hemodynamically relevant hematuria several months after biopsy of a kidney graft: an unusual cause.

We report the case of a 52-year-old female patient, who after a complicated living donor kidney transplantation, underwent kidney biopsy for suspected rejection. Duplex scanning revealed a small, asymptomatic arteriovenous (AV) fistula which was assessed as being hemodynamically unimportant. During follow-up, several urinary tract infections occurred and recurrent short episodes of hematuria were attributed to cystitis, urethritis and urosepsis. Eight months later, the patient developed suddenly massive hematuria, tamponade of the urinary bladder and hemorrhagic shock as well as urosepsis. Duplex sonography showed a massive pseudoaneurysm in addition to the AV fistula. Arteriography confirmed the Duplex sonographic findings and embolization was performed after treatment of concomitant urosepsis. The fistula was closed completely and bleeding ceased. Although AV fistulas are rare complications of kidney biopsies and in most cases they remain asymptomatic, life-threatening hematuria can present several months after a biopsy due to the development of a pseudoaneurysm. Concomitant infectious complications of the urinary tract, bleeding disorders and other factors can be misleading during the assessment of the cause of gross hematuria. Regular Duplex sonographic follow-up examinations in patients with AV fistulas are advisable.

[Aortoiliac reconstruction after kidney transplantation. Strategies to avoid ischemic damage of the transplant]. / Rekonstruktion der aortoiliakalen Strombahn bei Patienten nach Nierentransplantation. Strategien zur Vermeidung einer ischämischen Transplantatschädigung.

INTRODUCTION: The rising life expectancy of patients undergoing kidney transplantation and the improvement in the function rate of the allografts have led to an increasing number of patients suffering from arteriosclerosis-related diseases of the aortoiliac arteries. In these particular cases, an interruption of the blood supply of the allograft is always necessary for operative repair of the aortic and iliac arteries. This means a high risk of ischemic damage to the transplanted kidney. PATIENTS AND METHODS: Between 1987 and 2000, 1,076 kidney transplantations were performed in our department. During this time, 14 reconstructive operations of the aortoiliac arteries were performed in 12 patients (6 women, 6 men, average age 55.2 (45-71) years). Operations were indicated in patients suffering from occlusive disease with imminent extremity or allograft loss, and symptomatic or asymptomatic aneurysms with a maximum diameter of more than 4 cm. In patients presenting with thoracoabdominal (1) and abdominal aortic aneurysms (3), protection of the transplanted kidney was performed by axilloiliac or axillofemoral bypass. Hypothermic flush-perfusion of the allograft containing PGE1 and heparin was performed in seven of nine operations for occlusive disease. RESULTS: None of the patients presented with a permanent decrease in kidney function, six patients showed temporary creatinine elevation, and in nine patients creatinine levels at discharge were lower than they were preoperatively. None of the patients died. CONCLUSION: Reviewing all reported methods of allograft protection, we recommend a three-step strategy including sequential clamp technique (ischemia < 30 min.), hypothermic flush-perfusion (ischemia < or = 60 min.), and temporary axilloiliac/femoral shunt (ischemia > 60 min), depending on the expected renal ischemia time.

Exploring the pathway structure of metabolism: decomposition into subnetworks and application to Mycoplasma pneumoniae.

MOTIVATION: Reconstructing and analyzing the metabolic map of microorganisms is an important challenge in bioinformatics. Pathway analysis of large metabolic networks meets with the problem of combinatorial explosion of pathways. Therefore, appropriate algorithms for an automated decomposition of these networks into smaller subsystems are needed. RESULTS: A decomposition algorithm for metabolic networks based on the local connectivity of metabolites is presented. Interrelations of this algorithm with alternative methods proposed in the literature and the theory of small world networks are discussed. The applicability of our method is illustrated by an analysis of the metabolism of Mycoplasma pneumoniae, which is an organism of considerable medical interest. The decomposition gives rise to 19 subnetworks. Three of these are here discussed in biochemical terms: arginine degradation, the tetrahydrofolate system, and nucleotide metabolism. The interrelations of pathway analysis of biochemical networks with Petri net theory are outlined.

Exploring the minimal substrate requirements for trans-cleavage by RNase P holoenzymes from Escherichia coli and Bacillus subtilis.

We analysed the processing of small bipartite model substrates by Escherichia coli and Bacillus subtilis RNase P and corresponding hybrid enzymes. We demonstrate specific trans-cleavage of a model substrate with a 4 bp stem and a 1 nucleotide (nt) 5' flank, representing to date the smallest mimic of a natural RNase P substrate that could be processed in trans at the canonical RNase P cleavage site. Processing efficiencies decreased up to 5000-fold when the 5' flank was shortened from 3 to 1 nt. Reduction of the 5' flank to 1 nt was more deleterious than reducing the stem from 7 to 4 bp, although the 4 bp duplex formed only transiently, in contrast to the stable 7 bp duplex. These results indicate that the crucial contribution of nt -2 in the single-stranded 5' flank to productive interaction is a general feature of A- and B-type bacterial RNase P enzymes. We also showed that an Rp-phosphorothioate modification at nt -2 interferes with processing. Bacterial RNase P holoenzymes are also capable of cleaving single-stranded RNA oligonucleotides as short as 5 nt, yielding RNase P-specific 5'-phosphate and 3'-OH termini, with measured turnover rates of up to 0.7 min-1. All cleavage sites were at least 2 nt away from the 5' and 3' ends of the oligonucleotides. Some cleavage site preferences were observed dependent on the identity of the RNase P RNA subunit.

Cooperation and competition in the evolution of ATP-producing pathways.

Heterotrophic organisms generally face a trade-off between rate and yield of adenosine triphosphate (ATP) production. This trade-off may result in an evolutionary dilemma, because cells with a higher rate but lower yield of ATP production may gain a selective advantage when competing for shared energy resources. Using an analysis of model simulations and biochemical observations, we show that ATP production with a low rate and high yield can be viewed as a form of cooperative resource use and may evolve in spatially structured environments. Furthermore, we argue that the high ATP yield of respiration may have facilitated the evolutionary transition from unicellular to undifferentiated multicellular organisms.