Hydraulic properties of bentonite buffer material beyond 100 °C.

Bentonite buffer materials are important components of engineered barrier systems for the disposal of high-level radioactive waste produced during nuclear power generation. The design temperature of the buffer material is < 100 °C, and increasing the design temperature can reduce the required disposal area. This characteristic necessitates the evaluation of the thermal-hydraulic-mechanical properties of the buffer at temperatures above 100 °C to increase its target temperature. Therefore, the hydraulic properties of Gyeongju (KJ) bentonite buffer material were evaluated in this study, including the soil-water characteristic curve (SWCC) and hydraulic conductivity. An experimental system was manufactured to measure the suction and saturated hydraulic conductivity of KJ bentonite buffer material above 100 °C; the relative humidity of KJ bentonite buffer material was measured at 25-149 °C with an initial water content of 0, 0.06, and 0.12 under constant saturation conditions. The suction decreased as the temperature increased (10%-25% reduction at 99 °C-149 °C). The Van-Genuchten SWCC fitting parameters were also derived at 25 °C-149 °C using previously reported and newly generated experimental results, and the applicability of the modified Van-Genuchten SWCC model in this temperature range was verified. The hydraulic conductivity was proportional to temperature up to 100 °C, in agreement with the theoretical model results. Between 100 °C and 150 °C, the hydraulic conductivity increased nonlinearly because of molecular motion and structural changes inside the sample.

Reverse Sural Artery Island Flap With Skin Extension Along the Pedicle.

The distally based sural flap is an efficient flap for reconstruction of soft tissues defects of lower limb. The unstable vascular pedicle, however, is prone to compression by the subcutaneous tunnel, especially when a long pedicle covers the distal area of the foot. The aim of the present study was to introduce a modified surgical technique that leaves the skin extension over the pedicle and to report the clinical results of this modification. A total of 25 consecutive patients with a mean age of 51.7 ± 14.7 years underwent surgery. We modified the conventional sural flap technique by leaving a skin extension over the entire length of the pedicle, creating a fasciocutaneous vascular pedicle. The postoperative flap survival rates, complications, and the characteristics of the flaps such as flap size, pedicle length, and the most distal area that could be covered with this modification, were reviewed. At the last clinical follow-up examination, all the flaps survived, although partial necrosis was observed in 2 (8%) cases. Four cases of venous congestion developed but healed without additional complications. The mean flap size was 5.9 ± 1.8 × 9.2 ± 2.7 cm. With this modification, the sural flap could cover the defect located in extreme distal areas, such as the medial forefoot and dorsum of the first metatarsophalangeal joint, with a longer pedicle (≤27 cm) in 7 patients (28%). A skin extension along the pedicle achieved the favorable survival rate of the sural flap and successfully extended the surgical indications to more distal areas.

Uncalcified Synovial Chondromatosis in the Pisotriquetral Joint.

Synovial chondromatosis is a rare lesion in the wrist, but some cases in the distal radioulnar joint have been reported and previous case reports emphasize joint calcifications, shown on preoperative plain radiographs. We report an extremely uncommon case of synovial chondromatosis in the pisotriquetral joint, in which radiographs and magnetic resonance imaging did not demonstrate apparent calcified bodies. In our case, for the accurate diagnosis and treatment, surgical exploration of the joint and synovectomy with removal of loose bodies was performed.

Comparison of Flexor Tendon Suture Techniques Including 1 Using 10 Strands.

PURPOSE: To compare mechanical properties of a multistrand suture technique for flexor tendon repair with those of conventional suture methods through biomechanical and clinical studies. METHODS: We describe a multistrand suture technique that is readily expandable from 6 to 10 strands of core suture. For biomechanical evaluation, 60 porcine flexor tendons were repaired using 1 of the following 6 suture techniques: Kessler (2-strand), locking cruciate (4-strand), Lim/Tsai's 6-strand, and our modified techniques (6-, 8-, or 10-strand). Structural properties of each tenorrhaphy were determined through tensile testing (ultimate failure load and force at 2-mm gap formation). Clinically we repaired 25 flexor tendons using the described 10-strand technique in zones I and II. Final follow-up results were evaluated according to the criteria of Strickland and Glogovac. RESULTS: In the biomechanical study, tensile properties were strongly affected by repair technique; tendons in the 10-strand group had approximately 106%, 66%, and 39% increased ultimate load to failure (average, 87 N) compared with those in the 4-, 6-, and 8-strand groups, respectively. Tendons in the 10-strand group withstood higher 2-mm gap formation forces (average, 41 N) than those with other suture methods (4-strand, 26 N; 6-strand, 27 N; and 8-strand, 33 N). Clinically, we obtained 21 excellent, 2 good, and 2 fair outcomes after a mean of 16 months (range, 6-53 mo) of follow-up. No patients experienced poor results or rupture. CONCLUSIONS: The 10-strand suture repair technique not only increased ultimate strength and force at the 2-mm gap formation compared with conventional suture methods, it also showed good clinical outcomes. This multistrand suture technique can greatly increase the gap resistance of surgical repair, facilitating early mobilization of the affected digit. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

A retrospective analysis of 154 arterialized venous flaps for hand reconstruction: an 11-year experience.

BACKGROUND: The purpose of this study was to present the authors' 11-year clinical experience involving 154 cases of arterialized venous flaps for hand reconstruction. METHODS: The authors classified the venous flaps based on their size and composition. According to their size, flaps smaller than 10 cm were classified as small (n = 48), flaps larger than 25 cm were classified as large (n = 42), and those in between were classified as medium (n = 64). Classified according to their composition, there were 88 cases (57.1 percent) of venous skin flaps, 28 cases (18.2 percent) of innervated venous flaps, 15 cases (9.7 percent) of tendocutaneous venous flaps, and 17 cases (11 percent) of conduit venous flaps to repair arterial defects. There were six cases (3.9 percent) of composite venous flaps. RESULTS: The success rate of the flap transfer was 98.1 percent. The incidence of partial flap necrosis was 5.2 percent. The mean number of included veins was 2.17 for a small flap, 2.60 for a medium-sized flap, and 4.07 for a large flap (p < 0.01). The mean area of flap necrosis was 45.0 percent, 31.67 percent, and 18.75 percent for small, medium, and large flaps, respectively (p = 0.807). In eight cases of innervated venous flaps, the average static two-point discrimination was 10 mm (range, 8 to 15 mm). In 12 cases of tendocutaneous venous flaps, active range of motion at the proximal interphalangeal, distal interphalangeal, and metacarpophalangeal joints was 60, 20, and 75 degrees, respectively. CONCLUSIONS: The authors conclude that the arterialized venous flap is a valuable and effective tool for reconstructing complex hand injuries and may have a more comprehensive set of indications.

Immediate partial great toe transfer for the reconstruction of composite defects of the distal thumb.

BACKGROUND: Thumb defects distal to the interphalangeal joint do not cause any disability; therefore, any consideration to reconstruct the thumb is governed by the lifestyle and cultural background of the patient. This study presents the excellent results achieved by immediate partial great toe-to-hand transfer to reconstruct acute composite defects of the distal thumb. METHODS: Fifty-three patients with amputation or crush injury of the distal thumb who underwent partial great toe-to-hand transfer at the authors' institute over an 11-year period were reviewed. Based on the amputation level of the distal thumb, the authors classified the injuries into three groups. Operative techniques used were osteo-onychocutaneous flap with partial or whole toenail from the great toe and partial great toe transfer with arthrodesis of the interphalangeal joint. Overall results were evaluated in terms of success rate, incidence of emergency reexploration, and number and type of secondary operation. Static two-point discrimination, range of motion, pinch strength, and subjective satisfaction were also evaluated. RESULTS: The success rate of immediate partial great toe-to-hand transfer was 100 percent. The incidence of inflammation and the reexploration rate were not significantly different from those in previously reported articles. In 35 cases where postoperative follow-up was possible, static two-point discrimination, total active range of motion, and pinch strength were generally excellent and the majority of the patients were satisfied with the final outcome. CONCLUSION: Immediate reconstruction with partial great toe transfer is an excellent option for reconstruction of composite defects of the distal thumb, not only for aesthetic reasons but also for functional purposes.