[Feasibility, efficacy and safety of transbrachial access for interventional therapy on paravalvular leak post surgical valve replacement].

Objective: To investigate the feasibility, efficacy and safety of transbrachial access for interventional therapy on prosthetic paravalvular leak (PVL) post surgical valve replacement. Methods: This is a retrospective study. Patients with PVL after surgical valve replacement who underwent interventional therapy via the brachial artery approach in Structural heart disease center of Fuwai hospital between August 2017 and October 2019, were included. All patients underwent puncture of the brachial artery under local anesthesia, angiography and transcatheter closure procedure were performed. The procedure was performed under transthoracic echocardiography (TTE) guidance. Baseline data, operation data and pre-and post-operative TTE examination results were collected and analyzed. Postoperative complications were recorded and operational adverse events were obtained during follow up in the outpatient department after discharge. The operation success rate was calculated, which was defined as the degree of perivalvular regurgitation decrease by 1 grade and above according to TTE without interfering the valve movement and coronary artery blood flow within 30 days after occluder placement. Results: A total of 10 patients were enrolled in this study, the mean age was (57.5±14.6) years, and 6 patients were males. There were 7 cases with aortic PVL, and 3 cases with mitral PVL. Except for one patient who was converted to the femoral vein-transseptal approach, the other 9 patients were successfully implanted with the devices via the brachial artery approach. The operation time was (103.3±34.0) minutes, and there was no need for rigorous bed rest after the operation. The median hospital stay was 7.5 (3.0, 9.8) days. The operation success rate was 9/10 via the brachial artery approach. The differences in the degree of perivalvular regurgitation, New York Heart Association (NYHA) classification, left ventricular end diastolic diameter and left atrial diameter before and after operation were statistically significant (all P<0.05). One case developed new hemolysis with renal insufficiency on the second day after procedure and discharged after successful dialysis. Another case experienced complication of brachial artery pseudoaneurysm after procedure and discharged after successful treatment with thrombin injection. The mean follow-up time was (14.3±7.9) months. During the follow-up, NYHA classification remained as Ⅰ/Ⅱ in 9 patients, no operational adverse events were observed. Conclusions: Transbrachial access for interventional therapy on PVL post surgical valve replacement is a feasible, effective, and safe procedure. It has the advantages of simplifying the operation process and reducing postoperative bed rest time.

In Vivo changes in the lengths of carpal ligaments after mild dorsal angulation of distal radius fractures.

The need for surgical correction in patients with malunion with mild dorsal angulation after a distal radius fracture is controversial. We specifically investigated in vivo changes in the lengths of carpal ligaments in a group of patients with mild-degree dorsal angulation following a distal radial fracture. We obtained computed tomography scans of both wrists in eight patients, whose distal radius on one side had united with dorsal angulation from 10° to 20°. The three-dimensional images of the carpus were reconstructed and the lengths of wrist ligaments were measured based on known anatomical landmarks. Compared with the contralateral uninjured side, the dorsal radiocarpal ligament and ulnotriquetral ligament were substantially lengthened (p < 0.05) and the long radiolunate ligament was substantially shortened (p < 0.05) at most wrist positions except extension. However, five other ligaments that we measured did not show significant differences in length compared with those of the uninjured side (p > 0.05). The lengths of some ligaments are substantially altered even by mild dorsal angulation of the distal radius, while the lengths of most other ligaments are not substantially affected.

Digital oedema, adhesion formation and resistance to digital motion after primary flexor tendon repair.

The development of digital oedema, adhesion formation, and resistance to digital motion at days 0, 3, 5, 7, 9 and 14 after primary flexor tendon repairs using 102 long toes of 51 Leghorn chickens was studied. Oedema presented as tissue swelling from days 3 to 7, which peaked at day 3. After day 7, oedema was manifest as hardening of subcutaneous tissue. The degree of digital swelling correlated with the resistance to tendon motion between days 3 and 7. At day 9, granulation tissues were observed around the tendon and loose adhesions were observed at day 14. Resistance to digital motion increased significantly from day 0 to day 3, but did not increase between days 3 and 9. The early postoperative changes appear to have three stages: initial (days 0-3, increasing resistance with development of oedema), delayed (days 4-7, higher resistance with continuing oedema) and late (after day 7-9, hardening of subcutaneous tissue with development of adhesions).

The gliding force and work of flexion in the early days after primary repair of lacerated flexor tendons: an experimental study.

We measured the resistance to tendon mobilisation within the first 5 days after primary repair of digital flexor tendons of chickens. Forty-six long toes of 23 chickens were assigned to six surgical groups and one unoperated control group. The tendons were partially lacerated and surgically repaired. The resistance to simulated active digital flexion was assessed in six operated groups at 0, 1, 2, 3, 4 and 5 days postoperatively. The force of tendon motion and work of flexion increased gradually from day 0 to day 5. The force and work at days 4 and 5 were significantly higher than those at days 0 and 1. No statistical difference was found in the resistance at days 0, 1, 2 and 3. Our results indicate that the gliding resistance gradually increases over the first 5 days after surgery and suggest that tendon motion may be started after the first 3 days, to avoid moving during this period of increased resistance with increased risk of tendon rupture.

Medial sural artery perforator flap for repair of the hand.

We report our experience of using the medial sural artery perforator flap in the reconstruction of soft tissue defects in the hand in seven cases with 1 to 2 year follow-up. The flap is harvested from the posteromedial aspect of the leg, just below the knee and superficial to the medial head of the gastrocnemius muscle. It is based on the perforator arteries and veins supplied by the medial sural artery. The flaps ranged in size from 14 x 10 cm to 8 x 6 cm. The donor area was closed directly or by a skin graft. All but one flap survived. The cosmetic results were satisfactory and without apparent bulkiness. Similarity of colour and thickness of the donor and recipient sites are advantages. We feel that this new flap is a satisfactory option for use in the hand, particularly for extended soft tissue defects on the dorsal hand.

Biomechanical analysis of a modification of Tang method of tendon repair.

We report a modification of the original Tang technique of tendon repair which uses fewer sutures and has fewer knots on the tendon surface. The modified method consists of six longitudinal and two horizontal strands that form an "M" configuration within the tendon and four dorsal longitudinal strands made with a single looped suture. Thirty-six fresh pig flexor tendons were divided and repaired with either the modified Tang or the Tang method. The tendons were subjected to linear or 90 degrees angular loading in an Instron tensile machine. The gap formation strength and ultimate strength of the modified Tang repair was statistically identical to those of the Tang method under linear tension. Under angular tension, the ultimate strength of the modified Tang method was greater than that of the Tang method.

Dorsal-enhanced sutures improve tension resistance of tendon repair.

Thirty-six fresh pig flexor tendons were repaired using either the modified Kessler method or the Tang method. Nine tendons from each group were tested in an Instron tensile testing machine with the tendons passing 90 degrees around a pulley. The other nine tendons from each group were pulled linearly by the testing machine. The 2 mm gap formation force of the tendons repaired with the modified Kessler and Tang methods and pulled at 90 degrees were 64%+/-5% and 79%+/-9% respectively of those forces recorded during linear testing. The ultimate strengths of tendons repaired by the modified Kessler and Tang methods and pulled at 90 degrees were 76%+/-6% and 81%+/-8% respectively of the forces measured during linear testing. The percentage gap formation and ultimate strength of the Tang method was significantly higher than that of the modified Kessler suture when the tendons were pulled around a pulley. This demonstrates that the Tang suture, with its main components in the dorsal part of the repaired tendon, has greater tension resistance capacity than conventional tendon sutures which are placed in the middle of the tendon. This study suggests that dorsally-enhanced multiple tendon sutures are better placed to sustain the tension generated during active finger flexion.

Effects of tension direction on strength of tendon repair.

We investigated changes of tensile strength in tendon repair according to tension direction. Thirty-six fresh-frozen digital flexor tendons were divided into 4 groups with 9 tendons each. The tendons were repaired by the modified Kessler method. Sutured tendons were pulled against pulleys at angles of 0 degrees, 30 degrees, 60 degrees, and 90 degrees to the direction of the pull of the testing machine in the 4 groups, respectively. The repaired tendons were tested in a tensile machine to determine 2-mm gap formation force and ultimate strength of the tendons. The 2-mm gap formation force and ultimate strength in the tendons pulled at 0 degrees were statistically higher than those in the tendons pulled at 30 degrees, 60 degrees, and 90 degrees. The 2-mm gap formation force of the tendons pulled at 30 degrees, 60 degrees, and 90 degrees was 86% +/- 10%, 73% +/- 9%, and 64% +/- 8% of that at 0 degrees, respectively. Ultimate strength of tendons pulled at 30 degrees, 60 degrees, and 90 degrees was 89% +/- 9%, 82% +/- 11%, and 76% +/- 8% of that at 0 degrees, respectively. Values of the 2-mm gap formation force and ultimate strength were statistically the lowest in the group with a pulling angle of 90 degrees. There was no statistically significant difference in repair strength between tendons tested at 0 degrees and those in the model without pulleys. The strength of tendon repair changed considerably according to direction of tension added to the tendons. The gap formation force and ultimate strength decreased as angles of tension increased. The results imply that a repaired tendon will be weakened as the finger is increasingly flexed. The decrease in repair strength should therefore be considered in planning a tendon suture to tolerate active finger flexion and a tendon motion protocol after primary tendon repair.

Effect of A3 pulley and adjacent sheath integrity on tendon excursion and bowstringing.

The effect of the A3 pulley and adjacent sheath integrity on tendon function at the proximal interphalangeal (PIP) joint was investigated in 21 fingers in 7 fresh-frozen cadaver hands. Excursions of the flexor digitorum profundus (FDP) tendons were measured when the tendons were pulled to produce PIP joint flexion of 110 degrees from a resting position of 0 degrees. Excursions of the FDP tendons in 10 fingers were tested within the intact sheath and after incision of the A3 pulley, of the A3 pulley with its proximal sheath up to the distal border of the A2 pulley, and of the sheath between the A2 and A4 pulleys. Eleven fingers were tested after incision of the A3 pulley, of the A3 pulley and its distal sheath up to the A4 pulley, and of the sheath from the A3 to A4 pulleys. Excursions of the FDP tendons increased to 103% +/- 3% after incision of the A3 pulley, 110% +/- 4% after incision of the A3 pulley and its proximal sheath, and 107% +/- 6% after incision of the A3 pulley and its distal sheath. Excursions increased to 116% +/- 6% after incision of the sheath from the A3 to A4 pulleys and to 119% +/- 3% after incision of the sheath between the A2 and A4 pulleys. Tendon bowstringing was 0.3 mm after incision of the A3 pulley, 0.6 mm after incision of the A3 pulley with its distal sheath, 0.8 mm after incision of the pulley with its proximal sheath, 1.4 mm after incision of the sheath from the A3 to A4 pulleys, and 1.6 mm after incision of the sheath between the A2 and A4 pulleys. The results suggest that the sheath adjacent to the A3 pulley plays an important role in restraining tendon bowstringing at the PIP joint, whereas the A3 pulley alone is of little importance. This study elucidates the role of individual parts of the sheath around the PIP joint in maintaining tendon function and may guide decisions regarding the area and length of the sheath feasible for surgical release or requiring repair in the treatment of tendon lacerations.

Biomechanical evaluation of flexor tendon repair techniques.

Immediate active mobilization of repaired tendons is thought to be the most effective way to restore function of injured flexor tendons. Sixty human flexor digitorum profundus tendons were used to evaluate techniques for active tendon motion. The tendons were divided equally into six groups, and each group was assigned to one of the following techniques: Kessler core suture plus running peripheral suture, Kessler plus cross-stitch suture, Kessler plus Halsted suture, Tang core suture plus running peripheral suture, Tang plus cross-stitch suture, or Tang plus Halsted suture. Immediately after tendon repair, an Instron tensile testing machine was used to measure the 2-mm gap formation force, ultimate strength, elastic modulus, and energy to failure of the tendons repaired by these techniques. Ultimate strength, elastic modulus, and energy to failure were measured in load displacement curve. Results showed that the ultimate strength of the Tang plus Halsted or cross-stitch was, respectively, 116.8 +/- 9.6 N and 94.6 +/- 7.8 N; and 2-mm gap formation force was, respectively, 86.6 +/- 4.9 N and 71.9 +/- 5.1 N. The Tang plus Halsted or cross-stitch methods had a statistically significant increase in ultimate strength and 2-mm gap formation force as compared with the Kessler core suture or Tang plus running peripheral suture method. Elastic modulus and energy to failure of the Tang plus Halsted or cross-stitch suture were statistically higher than those of other techniques. The Tang plus cross-stitch or Tang plus Halsted sutures had the highest strength among the tested methods and are appropriate techniques for tendon repair in which the goal is immediate active tendon motion.

Novel chiral imidazole cyclophane receptors: synthesis and enantioselective recognition for amino acid derivatives.

Novel chiral imidazole cyclophane receptors were synthesized by highly selective N-alkylation of the imadazolyl 1N-position of the bridged histidine diester 2 with the dibromide in the presence of NaH; these receptors exhibit good chiral recognition toward the enantiomers of L- and D-amino acid derivatives (up to KD/KL = 3.52, delta delta G0 = -3.11 kJ mol-1) in CHCl3 at 25.0 degrees C.

A biomechanical study of Tang's multiple locking techniques for flexor tendon repair.

This study was designed to biomechanically compare Tang's multiple looped locking techniques with various suture techniques for flexor tendon repair in the hand. Fifty flexor digitorum profondus tendons taken from pig toes were used as models; The tendons were transected in the middle part of zone 2 defined as the area beneath bifurcation of the flexor digitorum superficialis tendons, and were repaired by five different suture methods: (1) modified Kessler, (2) Tsuge's suture, (3) double Kessler, (4) modified Kessler plus Tsuge, and (5) Tang's suture. The repaired tendons were placed in an Instron tensile testing machine to determine the tensile properties of the repair. 2 mm gap formation force and ultimate tensile strength were measured during the test. Maximal work to failure were calculated according to area under the load-displacement curve of the test. 2 mm gap formation force was 21.5 N for the Kessler, 20.6 N for the Tsuge, 31.6 N for double Kessler, 30.9 N for the Kessler plus Tsuge and 41.4 N for the Tang. Ultimate tensile strength was 23.5 N for the Kessler, 22.9 N for the Tsuge, 34.5 N for the Kessler plus Tsuge and 45.6 N for the Tang. Statistically, Tang's suture had the greatest gap formation force, ultimate strength and energy for failure among the five techniques (p < 0.01 or p < 0.001). Gap formation force, ultimate strength and energy to failure for double Kessler or the Kessler plus Tsuge were significantly greater than those for the Kessler or the Tsuge (p < 0.05 or < 0.01). The tendons repaired by Tang's method tolerated a significantly higher tensile load (133 to 198% of the other techniques) than the other methods. Among the methods tested, Tang's multiple looped locking suture provides sufficient gap resistance and tensile strength that may be able to withstand early active mobilization after primary flexor tendon repair.

A new efficient synthetic method for 2- and 4-hydroxy-17 alpha-ethynylestradiol.

The reaction of ethyl magnesium bromide and 17 alpha-ethynylestradiol with formaldehyde in the presence of triethyl phosphate or hexamethylphosphoramide gave the 2- and 4-formyl-17 alpha-ethynylestradiol in high yield. Treatment of the formyl derivatives with an alkaline solution of hydrogen peroxide in tetrahydrofuran afforded the corresponding catechols in almost quantitative yield. This new synthetic method was far superior to other methods, especially concerning simplicity, selectivity, and high yields.