Decompression corrective osteotomy of the distal radius for treatment of the DRUJ-incongruency and impingement syndrome with focus on posttraumatic cases.

INTRODUCTION: Posttraumatic or congenital ulna-minus variance with altered shape of the sigmoid notch and increased tension of the distal oblique band of the interosseous membrane (DIOM) can lead to painful impingement in the distal radioulnar joint (DRUJ) during rotation and loading of the forearm. As an operative treatment concept, a new method was described in 2016. Its goal is to restore the osseous congruency, which is required for normal painless function. The hypothesis is based on remodelling of the joint surface and the decompression of the DRUJ by releasing the DIOM. The purpose of this study is to analyze the results of performed operations with detailed focus on posttraumatic cases. MATERIALS AND METHODS: The indication for the operation is the impingement and incongruency in the DRUJ with ulna-minus variance. The surgical procedure is based on shortening and closed-wedge osteotomy of the distal radius with an ulnar translation of the radial shaft. Fifty-nine operations were performed between 2011 - 2022 on 52 patients (13 men, 39 women). Twenty-four patients were operated on the right side, 21 on the left side and 7 bilaterally. In 45 cases the operation was indicated because of congenital, in 12 cases due to posttraumatic incongruency and in 2 cases because of iatrogenic impingement after previously performed excessive ulnar shortening osteotomy. Modified Mayo-Wrist-Score, patient questioning, VAS and ROM were used to evaluate the results. RESULTS: Significant reduction of pain on VAS from 7.22 to 1.98 (p < .001) was achieved. The pre- and postoperative range of motion did not show any significant changes (mean total arc of motion 301,94° vs. 295,20°, p = .300). Specific complications we observed included a too distally performed osteotomy, DRUJ instability, de Quervain´s tenosynovitis, persistent pain and conversion into an ulna-plus variance. CONCLUSION: Under consideration of the indication criteria and correct execution of the osteotomy, in about 90 % of the cases this operation leads to good-to-excellent results with pain reduction and improvement of weight-bearing and power. The preoperative examination, verification of the DRUJ stability and the radiological diagnostics are crucial for a good outcome.

Variations of the extrapsoas course of the lumbar plexus with implications for the lateral transpsoas approach to the lumbar spine: a cadaveric study.

BACKGROUND: Together with an increased interest in minimally invasive lateral transpsoas approach to the lumbar spine goes a demand for detailed anatomical descriptions of the lumbar plexus. Although definitions of safe zones and essential descriptions of topographical anatomy have been presented in several studies, the existing literature expects standard appearance of the neural structures. Therefore, the aim of this study was to investigate the variability of the extrapsoas portion of the lumbar plexus in regard to the lateral transpsoas approach. METHODS: A total of 260 lumbar regions from embalmed cadavers were utilized in this study. The specimens were dissected as per protocol and all nerves from the lumbar plexus were morphologically evaluated. RESULTS: The most common variation of the iliohypogastric and ilioinguinal nerves was fusion of these two nerves (9.6%). Nearly in the half of the cases (48.1%) the genitofemoral nerve left the psoas major muscle already divided into the femoral and genital branches. The lateral femoral cutaneous nerve was the least variable one as it resembled its normal morphology in 95.0% of cases. Regarding the variant origins of the femoral nerve, there was a low formation outside the psoas major muscle in 3.8% of cases. The obturator nerve was not variable at its emergence point but frequently branched (40.4%) before entering the obturator canal. In addition to the proper femoral and obturator nerves, accessory nerves were present in 12.3% and 9.2% of cases, respectively. CONCLUSION: Nerves of the lumbar plexus frequently show atypical anatomy outside the psoas major muscle. The presented study provides a compendious information source of the possibly encountered neural variations during retroperitoneal access to different segments of the lumbar spine.

[Treatment of Congenital Ulnar Impingement Syndrome by Corrective Osteotomy of the Distal Radius - Clinical Results]. / Therapie des kongenitalen ulnaren Impingement-Syndroms durch dekomprimierende Korrekturosteotomie des distalen Radius ­ klinische Ergebnisse.

BACKGROUND: In 2016, a new method was described to treat the painful impingement syndrome of the DRUJ: decompression corrective osteotomy of the distal radius. Clinical symptoms are based on a positive compression test; pain occurs with weight-bearing on the forearm. This phenomenon is seen in conjunction with a deformed sigmoid notch together with ulna minus-variance, which leads to increased tension in the distal oblique bundle of the interosseous membrane. The etiology of the condition can be either congenital, post-traumatic, or iatrogenic. Through the proposed osteotomy, decompression in the DRUJ is achieved. This study summarises the results of these surgical procedures performed in our hand centre exclusively in cases of congenital origin. PATIENTS UND METHODS: Remodelling of the DRUJ is achieved through the shortening of the distal radius together with closed wedge osteotomy. Relief of the interosseous membrane is accomplished by ulnar translation of the radial shaft. This study only included patients with congenital incongruency in the DRUJ. The results were evaluated using a visual analogue scale (VAS) and the Krimmer Wrist Score and by measuring the preoperative and postoperative range of motion as well as grip strength. RESULTS: Within 11 years, 45 procedures were performed with our method on 38 patients, of which 17 were treated on the right side, 14 on the left side, and 7 bilaterally. In cases of bilateral incongruency, only the symptomatic side was treated. The statistical evaluation showed a significant reduction of pain on the VAS from 7.2 to 2 (p<0.001). No significant changes were seen in the range of motion (p=0.812). The Krimmer Wrist Score showed good to excellent results in almost 90% of cases. CONCLUSION: If the indication criteria are met, contraindications are avoided and the osteotomy is correctly performed, this technique leads to an improvement of patients' functionality and quality of life. From a preventive viewpoint, the influence on the progression of the degenerative changes is yet to be demonstrated in further studies. At any rate, this is a safe procedure, which leaves the path open for other possible options.

Copper Phosphinate Complexes as Molecular Precursors for Ethanol Dehydrogenation Catalysts.

Nowadays, the production of acetaldehyde heavily relies on the petroleum industry. Developing new catalysts for the ethanol dehydrogenation process that could sustainably substitute current acetaldehyde production methods is highly desired. Among the ethanol dehydrogenation catalysts, copper-based materials have been intensively studied. Unfortunately, the Cu-based catalysts suffer from sintering and coking, which lead to rapid deactivation with time-on-stream. Phosphorus doping has been demonstrated to diminish coking in methanol dehydrogenation, fluid catalytic cracking, and ethanol-to-olefin reactions. This work reports a pioneering application of the well-characterized copper phosphinate complexes as molecular precursors for copper-based ethanol dehydrogenation catalysts enriched with phosphate groups (Cu-phosphate/SiO2). Three new catalysts (CuP-1, CuP-2, and CuP-3), prepared by the deposition of complexes {Cu(SAAP)}n (1), [Cu6(BSAAP)6] (2), and [Cu3(NAAP)3] (3) on the surface of commercial SiO2, calcination at 500 °C, and reduction in the stream of the forming gas 5% H2/N2 at 400 °C, exhibited unusual properties. First, the catalysts showed a rapid increase in catalytic activity. After reaching the maximum conversion, the catalyst started to deactivate. The unusual behavior could be explained by the presence of the phosphate phase, which made Cu2+ reduction more difficult. The phosphorus content gradually decreased during time-on-stream, copper was reduced, and the activity increased. The deactivation of the catalyst could be related to the copper diffusion processes. The most active CuP-1 catalyst reaches a maximum of 73% ethanol conversion and over 98% acetaldehyde selectivity at 325 °C and WHSV = 2.37 h-1.

Propylene Metathesis over Molybdenum Silicate Microspheres with Dispersed Active Sites.

In this work, we demonstrate that amorphous and porous molybdenum silicate microspheres are highly active catalysts for heterogeneous propylene metathesis. Homogeneous molybdenum silicate microspheres and aluminum-doped molybdenum silicate microspheres were synthesized via a nonaqueous condensation of a hybrid molybdenum biphenyldicarboxylate-based precursor solution with (3-aminopropyl)triethoxysilane. The as-prepared hybrid metallosilicate products were calcined at 500 °C to obtain amorphous and porous molybdenum silicate and aluminum-doped molybdenum silicate microspheres with highly dispersed molybdate species inserted into the silicate matrix. These catalysts contain mainly highly dispersed MoOx species, which possess high catalytic activity in heterogeneous propylene metathesis to ethylene and butene. Compared to conventional silica-supported MoOx catalysts prepared via incipient wetness impregnation (MoIWI), the microspheres with low Mo content (1.5-3.6 wt %) exhibited nearly 2 orders of magnitude higher steady-state propylene metathesis rates at 200 °C, approaching site time yields of 0.11 s-1.

Ethanol Dehydrogenation over Copper-Silica Catalysts: From Sub-Nanometer Clusters to 15 nm Large Particles.

Non-oxidative ethanol dehydrogenation is a renewable source of acetaldehyde and hydrogen. The reaction is often catalyzed by supported copper catalysts with high selectivity. The activity and long-term stability depend on many factors, including particle size, choice of support, doping, etc. Herein, we present four different synthetic pathways to prepare Cu/SiO2 catalysts (∼2.5 wt % Cu) with varying copper distribution: hydrolytic sol-gel (sub-nanometer clusters), dry impregnation (A̅ = 3.4 nm; σ = 0.9 nm and particles up to 32 nm), strong electrostatic adsorption (A̅ = 3.1 nm; σ = 0.6 nm), and solvothermal hot injection followed by Cu particle deposition (A̅ = 4.0 nm; σ = 0.8 nm). All materials were characterized by ICP-OES, XPS, N2 physisorption, STEM-EDS, XRD, RFC N2O, and H2-TPR and tested in ethanol dehydrogenation from 185 to 325 °C. The sample prepared by hydrolytic sol-gel exhibited high Cu dispersion and, accordingly, the highest catalytic activity. Its acetaldehyde productivity (2.79 g g-1 h-1 at 255 °C) outperforms most of the Cu-based catalysts reported in the literature, but it lacks stability and tends to deactivate over time. On the other hand, the sample prepared by simple and cost-effective dry impregnation, despite having Cu particles of various sizes, was still highly active (2.42 g g-1 h-1 acetaldehyde at 255 °C). Importantly, it was the most stable sample out of the studied materials. The characterization of the spent catalyst confirmed its exceptional properties: it showed the lowest extent of both coking and particle sintering.

Smart Modulators Based on Electric Field-Triggering of Surface Plasmon-Polariton for Active Plasmonics.

Design and properties of a plasmonic modulator in situ tunable by electric field are presented. Our design comprises the creation of periodic surface pattern on the surface of an elastic polymer supported by a piezo-substrate by excimer laser irradiation and subsequent selective coverage by silver by tilted angle vacuum evaporation. The structure creation was confirmed by AFM and FIB-SEM techniques. An external electric field is used for fine control of the polymer pattern amplitude, which tends to decrease with increasing voltage. As a result, surface plasmon-polariton excitation is quenched, leading to the less pronounced structure of plasmon response. This quenching was checked using UV-Vis spectroscopy and SERS measurements, and confirmed by numerical simulation. All methods prove the proposed functionality of the structures enabling the creation smart plasmonic materials for a very broad range of advanced optical applications.

New Adamantane-like Silicophosphate Cage and Its Reactivity toward Tris(pentafluorophenyl)borane.

The condensation reaction between Ph2Si(OC(O)CH3)2 and OP(OSiMe3)3 leads to elimination of CH3C(O)OSiMe3 and the formation of the new silicophosphate cage molecule Ph12Si6P4O16 (1) with an adamantane-like core possessing four terminal P═O moieties and six O-SiPh2-O bridging groups. Compound 1 was further reacted with the Lewis acid B(C6F5)3. We observed adduct formation by coordination through the P═O→B bonds and isolated and structurally characterized two new molecules. In the first of them, the adamantane-like cage is preserved and three phosphoryl oxygen atoms coordinate to boranes, forming Ph12Si6O16P4·3B(C6F5)3 (2); the remaining P═O group is inverted toward the cage center pointing along a C3 molecular axis. The molecule is chiral, and the compound 2 crystallizes as a conglomerate of homochiral crystals. Enantiomers 2M and 2P were both structurally characterized. The second adduct resulted from an unexpected reorganization of the Si-O-P linkages in the adamantane cage during the reaction of 1 with 4 equiv of B(C6F5)3. The bis-adduct Ph6Si3O8P2·2B(C6F5)3 (3) was formed with an inorganic core representing half of the parent molecule 1.