Treatment of acute distal biceps tendon ruptures - A survey of the British Elbow and Shoulder Society surgical membership

Background

Acute distal biceps tendon ruptures result in weakness and deformity. While in other jurisdictions the rate of surgical repair has outpaced rises in incidence, UK practice for distal biceps tendon ruptures is unknown. The aim of this survey was to characterise current UK clinical practice.

Methods

An online survey was sent to the surgeon members of the British Elbow and Shoulder Society. Questions covered respondent demographics, clinical decision making, surgical experience and willingness to be involved in future research.

Results

A total of 242 surgeons responded; 99% undertook acute distal biceps tendon repairs with 83% repairing at least half of all distal biceps tendon ruptures, and 84% of surgeons would have their own, hypothetical, acute distal biceps tendon rupture repaired in their dominant arm and 67% for their non-dominant arm. Patient age, occupation and restoration of strength were the commonest factors underpinning a recommendation of surgical fixation. Most surgeons (87%) supported a national trial to study operative and non-operative treatments.

Conclusions

UK upper limb surgeons currently advise surgical repair of acute distal biceps tendon ruptures for the majority of their patients. This is despite a paucity of evidence to support improved outcomes following surgical, rather than non-operative, management. There is a clear need for robust clinical evaluation in this area.

The use of a patch to augment rotator cuff surgery - A survey of UK shoulder and elbow surgeons

Background

Rotator cuff tears are a common cause of shoulder pain and can result in prolonged periods of pain, disability and absence from work. Rotator cuff repair surgery is increasingly used in an attempt to resolve symptoms but has failure rates of around 40%. There is a pressing need to improve the outcome of rotator cuff repairs. Patch augmentation increasingly being used within the NHS in an attempt to reduce repair failures. The aim of this survey was to determine current UK practice and opinion relating to the factors that influence choice of patch, current patient selection and willingness to assist with generation of improved evidence.

Methods

An online survey was sent to the surgeon members of the British Elbow and Shoulder Society (BESS). Questions covered respondent demographics, experience with patches, indications for patch augmentation and willingness to be involved in a randomised trial of patch augmented rotator cuff surgery.

Results

The response rate was 105/550 (19%). 58% of respondents had used a patch to augment rotator cuff surgery. 70% of patch users had undertaken an augmented repair within the last 6 months. A wide surgical experience in augmentation was reported (ranging 1 to 200 implants used). However, most surgeons reported low volume usage, with a median of 5 rotator cuff augmentation procedures performed. At least 10 different products had been used. Most of the patches used were constructed from human decellularised dermis tissue, although porcine derived and synthetic based patches had also been used. Only 3–5% stated they would undertake an augmented repair for small tears across ages, whereas 28–40% and 19–59% would do so for large or massive tears respectively. When assessing patient suitability, patient age seemed relevant only for those with large and massive tears. Half of the surgeons reported an interest in taking part in a randomised controlled trial (RCT) evaluating the role of patch augmentation for rotator cuff surgery, with a further 22% of respondent’s undecided.

Conclusions

A variety of patches have been used by surgeons to augment rotator cuff repair with a wide range of operator experience. There was substantial uncertainty about which patch to use and differing views on which patients were most suitable. There is a clear need for robust clinical evaluation and further research in this area.

Time-resolved laser-induced desorption spectroscopy (LIDS) for quantified in-situ hydrogen isotope retention measurement and removal from plasma facing materials

A laboratory scale laser induced thermal desorption spectroscopy system is developed and tested on tungsten-deuterium and titanium-deuterium codeposits, and its feasibility as a hydrogenic inventory measurement diagnostic is demonstrated over a range of retention values from 5 × 10¹⁹ m^-2 to 7 × 10²³ m^-2 for absorbed laser power densities as low as 8 MW m^-2. Codeposit layer samples are grown by magnetron sputtering and immersed in a weak argon rf plasma. A 1 kW fiber laser (λ = 1100 nm) heats the samples up to a peak surface temperature ranging from 900 to 1500 K using pulse widths of 0.5 and 1 s. Spectral line emission from Balmer series Dα and Hα from thermally desorbed deuterium and hydrogen, as well as line emission from argon, are monitored as a function of time using an optical spectrometer with maximum temporal resolution of 1 ms. To correct for wall recycling and pumping speed, and to accurately measure the time evolution of the laser-induced thermal desorption, the raw Dα signal is deconvolved with the system response function, which is obtained by injecting a short burst of D₂ to approximate an impulse. Calibration is done with a standard D₂ leak, and laser induced desorption spectroscopy deuterium retention values are found to be in good agreement with companion measurements made using conventional temperature programmed desorption on samples from the same codeposit batch.

Post-thrombotic syndrome: a clinical review

Up to half of patients with proximal deep vein thrombosis (DVT) will develop post-thrombotic syndrome (PTS) despite optimal anticoagulant therapy. PTS significantly impacts upon quality of life and has major health-economic implications. This narrative review describes the pathophysiology, risk factors, and diagnosis, prevention and treatment of PTS, to improve our understanding of the disease and guide treatment. Relevant articles were identified through systematic searches of the PubMed, EMBASE and Cochrane databases between 1966 and November 2011. Studies were included for detailed assessment if they met the following criteria: published in English, human study participants, study population aged > 18 years, and lower limb post-thrombotic syndrome. All non-systematic reviews and single patient case reports were excluded. Recurrent thrombosis, thrombus location and obesity are major risk factors, whereas the importance of gender and age remain uncertain. The diagnosis of PTS is based on clinical findings in patients with a known history of DVT. Several clinical scales have been described, with the Villalta Score gaining increasing popularity. Adequate anticoagulation and use of elastic compression stockings (ECS) following DVT can reduce the incidence of PTS. Catheter-directed thrombolysis and mechanical thrombectomy of acute DVT may preserve valvular function. Studies to date of these techniques are encouraging, and have reported improved hemodynamics and a reduced incidence of PTS. The management of established PTS is challenging. Compression therapy, aimed at reducing the underling venous hypertension, remains the mainstay of treatment. This is despite a paucity of high-quality evidence to support its use. Pharmacologic and surgical treatments have also been described, with a number of studies citing symptomatic improvement.

Capillary electrophoretic application of 1-alkyl-3-methylimidazolium-based ionic liquids

Ionic substances with melting points at or close to room temperature are referred to as ionic liquids. Interest in ionic liquids for their potential in different chemical processes is increasing, because they are environmentally benign and are good solvents for a wide range of both organic and inorganic materials. In this study, a capillary electrophoretic method for resolving phenolic compounds found in grape seed extracts is reported. The method, in which 1-alkyl-3-methylimidazolium-based ionic liquids are used as the running electrolytes, is simple and reproducible. The separation mechanism seems to involve association between the imidazolium cations and the polyphenols. The role of the alkyl substituents on the imidazolium cations was investigated and will be discussed.

Structural and spectroscopic studies of the versatile coordination chemistry of the chiral ligand N,N-bis(1-propan-2-onyl oxime)-L-methionine N'-methylamide with Ni(II) and Zn(II)

The potentially pentadentate, chiral ligand N,N-bis(1-propan-2-onyl oxime)-L-methionine N'-methylamide (L-MABO) shows remarkable versatility in its coordination chemistry with Ni(II) and Zn(II). In the crystal structure of the ZnCl2 complex of L-MABO, the ligand coordinates to the metal only through its three nitrogen donor groups (one amine and two oximes), with two chloride anions completing the distorted trigonal bipyramidal coordination sphere. In the NiCl2 complex, the three nitrogen donors and the thioether sulfur coordinate, along with two chlorides. The crystal structure of the Ni(NO3)2 complex contains two independent molecules, one of which coordinates the three nitrogens, the thioether sulfur, and the amide oxygen of L-MABO in addition to one nitrate anion. The second molecule coordinates the three nitrogen donors, the amide oxygen, one nitrate anion, and a methanol molecule. Thus, in only three crystal structures, L-MABO demonstrates its ability to provide N3, N3S, N3O, and N3OS donor sets. The thioether-bound complexes are unusual in that they have a predominantly nitrogen environment with a nickel-thioether bond that is not constrained by surrounding donor groups in a macrocyclic or linear polydentate motif. Comparison of the thioether-coordinated and methanol-coordinated molecules in the Ni(NO3) salt of L-MABO demonstrate the effect of the thioether bond on the relative "hardness" of the nickel. The electronic absorption and circular dichroism spectra of the aqueous solutions of the nickel complexes are interpreted in terms of a "descent in symmetry" model based on successive C3v and Cs distortions from octahedral geometry. These ligand field spectra indicate that in aqueous solution all ligand groups except for the three nitrogens of L-MABO are displaced by water. In acetonitrile, the non-nitrogen donors in the nitrate salt may also be displaced, while the chlorides remain coordinated.

The effect of protonation on [Mn(IV)(μ2-O)] 2 complexes

The series of complexes [Mn(IV)(X-SALPN)(μ2-O)]2, 1: X=5-OCH3; 2: X=H; 3: X=5-Cl; 4: X=3,5-diCl; 5: X=5-NO2, contain [Mn2O2](4+) cores with Mn-Mn separations of 2.7 Å. These molecules can be protonated to form [Mn(IV)(X-SALPN)(μ2-O,OH)]2 (+) in which a bridging oxide is protonated. The pKa values for the series of [Mn(IV)(X-SALPN)(μ2-O,OH)]2 (+) track linearly versus the shift in redox potential with a slope of 84 mV/pKa. This observation suggests that the [Mn2O2](4+) core can be considered as a unit in which the free energy of protonation is directly related to the ability to reduce the Mn(IV) ion. The marked sensitivity of the reduction potential to the presence of protons presents a mechanism in which an enzyme can control the oxidizing capacity of an oxo manganese cluster by the degree and timing of oxo bridge protonation.

Reaction of ethanesulfenyl chloride with 2-methoxy-5,6-dihydro-2H-pyran

The reaction of ethanesulfenyl chloride with 2-methoxy-5,6-dihydro-2H-pyran gives only 4β-chloro-3α-ethylthio-2β-methoxytetrahydropyran. A rationale is presented to explain the observed highly selective reaction.

Some reactions of 2,4-dimethoxytetrahydropyrans

Acid-catalyzed elimination of methanol from 2,4-dimethoxytetrahydropyran (1) produces 2-methoxy-5,6-dihydro-2H-pyran (3) rather than the expected olefin 4-methoxy-3,4-dihydro-2H-pyran (2).The reaction of 1,3-dibromo-5,5-dimethylhydantoin with 3 in ether – methanol gives a 2:1 mixture of the isomers 3β-bromo-2α,4α-dimethoxytetrahydropyran (5a) and 3α-bromo-2α,4β-dimethoxytetrahydropyran (5b) respectively. A rationale is given to explain the preponderance of 5a over 5b and the highly selective attack of the bromine of the hydantoin and the methanol on C-3 and C-4 respectively of the double bond of 3. Reduction of 5ab with zinc in ethanol provides only compound 3.The room temperature reaction of 1 in a mixture of water and 1,2-dimethoxyethane containing Amberlite IR-120, produces 2-hydroxy-4-methoxytetrahydropyran (6) as an equilibrium mixture of cis and trans isomers in the ratio 1:1. This gave a value of 0.9 kcal/mole for the anomeric effect in 6. Pyrolysis of the derivative, 2-acetoxy-4-methoxytetrahydropyran failed to produce the olefin 2 and resulted only in extensive decomposition.

Concerning the mechanism of the addition of ethanesulfenyl chloride to 3,4-dihydro-2H-pyran

The nuclear magnetic resonance spectrum, at −40°, of the crude mixture obtained by the reaction of ethanesulfenyl chloride with 3,4-dihydro-2H-pyran at −40° clearly supports the view that the product is trans-2-chloro-3-ethylthiotetrahydropyran. The possibility that there is initial formation of 3-chloro-2-ethylthiotetrahydropyran followed by its rapid rearrangement to 2-chloro-3-ethylthiotetrahydropyran is ruled out because of the stability of 3-chloro-2-ethylthiotetrahydropyran to distillation under vacuum. The latter compound is obtained as a mixture of cis and trans isomers by the reaction of ethyl mercaptan with 5-chloro-3,4-dihydro-2H-pyran in the presence of sulfur dioxide.

The preparation of 3-alkylthio-2-methoxytetrahydropyrans

The reaction of alkylsulfenyl chlorides with 3,4-dihydro-2H-pyran, followed by treatment of the product with sodium methoxide, gave, highly stereoselectively, trans-3-alkylthio-2-methoxytetrahydropyrans. Purification by distillation under a vacuum at temperatures above 55° resulted in the elimination of methyl alcohol to produce 5-(alkylthio)-3,4-dihydro-2H-pyrans in a good yield. At lower temperatures, the more volatile homologues could be distilled undecomposed, but these had undergone thermal isomerization to a mixture of cis- and trans-3-alkylthio-2-methoxytetrahydropyrans. The conformational preference of these isomers is discussed.

REARRANGEMENT OF ALLYL 2,6-DICHLOROPHENYL ETHER ON COLUMN PACKINGS DURING GAS–LIQUID CHROMATOGRAPHIC ANALYSIS

At temperatures above 175° and with packed columns, rearrangement of allyl 2,6-dichlorophenyl ether occurs during gas–liquid chromatographic analysis with a contact time of no more than 4 min. For example, at a temperature of 205° with Gas Chrom P as packing material, about 7% of the ether is changed, but the packing 20% Apiezon L on Gas Chrom P increases this to about 50%. Products characteristic of both thermal and acid-catalyzed rearrangements are obtained. The number of such products increases to a maximum of five as the temperature is increased to 228°.Accordingly, the results of gas–liquid chromatographic analysis of mixtures obtained from the Claisen rearrangement of allyl phenyl ethers must be interpreted with care if unchanged ether is present.

CONCERNING THE PREPARATION OF p-ALLYLPHENOL FROM SAFROLE BY SODIUM – LIQUID AMMONIA REDUCTION

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