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Biomedical subjects

Masato Kurokawa

Publications and source records attributed to Masato Kurokawa.

7 recordsLinked to original sources

Nonmicrosurgical replantation using a subcutaneous pocket for salvage of the amputated fingertip.

PURPOSE: The pocket principle suggested by Brent in 1979 is an alternative method for use when microsurgical replantation is not feasible. The application and the amputation level for which the method is available, however, have not been well examined. METHODS: Between 1999 and 2003 we treated 6 patients (7 fingers) by nonmicrosurgical replantation using a subcutaneous pocket (the Brent technique). All patients had sustained complete fingertip amputations across or proximal to the lunula in digits other than the thumb. In every case the amputation was a crush or avulsion-type injury and microsurgical replantation was not feasible; however, cosmetic symmetry was desired strongly by the patient. RESULTS: Of the 7 fingers only one survived completely but became atrophic after 4 months. One finger developed necrosis involving less than half of the replant but a hooked nail deformity developed. Two fingers developed partial necrosis involving more than half of the replant but both fingers were missing the fingernail and the cosmetic results were not acceptable. Three fingers developed total necrosis. In addition a slight flexion contracture not improved with therapy in the digits was noted in 4 patients. CONCLUSIONS: The Brent technique should be performed scrupulously for fingertip amputation across or proximal to the lunula because of the poor survival rate and the possibility of contracture in the digits or other proximal joints.

Adult↗

The PNB classification for treatment of fingertip injuries: the boundary between conservative treatment and surgical treatment.

The PNB classification, which was advocated by Evans and Bernadis, separates the injuries into their effects on 3 components of the fingertip: pulp, nail, and bone. Because each component is subdivided into 7 or 8 items, this can describe fingertip injuries more precisely. Between 1997 and 2003, we treated 381 fingertip injuries (279 males, 102 females; average age, 41.2 years) in our facilities. A 3-digit number was provided for each of the 381 cases in accordance with the PNB classification. We extracted patients in whom amputated tissues did not exist, and predicted the boundary between conservative treatment and surgical treatment by individually comparing the curative results of the same type of injuries. In conclusion, PNB 355-366 and PNB 455-466 were most suitable for surgical treatment, and the boundaries between surgical treatment and conservative treatment were PNB 386 and 666 and 700. The results, which are the criteria for surgical treatment, are summarized as follows; 1) More than two thirds of the distal phalanx remains. 2)The nail bed defect ranges from one third to half. If the defect is more or less than the criteria, the surgical treatment is less significant. Recognition of the boundary and prevention from unnecessary surgical treatment leads to minimum invasive surgery for fingertip injuries.

Adolescent↗

Production and characterization of a silk-like hybrid protein, based on the polyalanine region of Samia cynthia ricini silk fibroin and a cell adhesive region derived from fibronectin.

There are a variety of silkworms and silk fibroins produced by them. Silks have many inherent suitable properties for biomaterials. In this paper, a novel silk-like hybrid protein, [DGG(A)(12)GGAASTGRGDSPAAS](5), which consists of polyalanine region of silk fibroin from a wild silkworm, Samia cynthia ricini, and cell adhesive region including Arg-Gly-Asp (RGD) sequence, derived from fibronectin, was designed and produced. The genes encoding the hybrid protein were constructed and expressed in Escherichia coli. The main conformation of the polyalanine region, that is, either alpha-helix or beta-sheet, could be easily controlled by treatment with different acidic solvents, trifluoroacetic acid or formic acid, respectively. This structural change was monitored with 13C CP/MAS NMR. Higher cell adhesive and growth activities of the hybrid protein compared with those of collagen were obtained.

Animals↗

Successful replantation of an amputated leg with severe crush and avulsion injury in an elderly patient: case report.

An amputated leg with severe crush and avulsion injury was replanted in a 57-year-old man. Since the skin and soft tissue around the ankle became necrotic 11 days postoperatively, a flow-through forearm free flap was transferred into the defect, preserving the blood circulation to the replanted leg. Seven weeks after the replantation, sural nerve cable grafts were interposed between both amputated edges of the tibial nerve. As the function of the ankle joint did not recover, arthrodesis of the ankle joint was performed 7 months after the replantaion. As a result, the patient could walk 1 year postoperatively.

Amputation, Traumatic↗

A method for correcting an inverted nipple with an artificial dermis.

Various methods have been reported to correct an inverted nipple. Although a satisfactory outcome has been reported with most techniques, each method carries a drawback inherent in the technique itself, including complicated operative technique, sensory disturbance of the nipple, marked scarring of the nipple areola and other donor regions, destruction of breast function, and incomplete correction. This report describes a simple method for correcting an inverted nipple. It incorporates a new concept of using artificial dermis for tissue augmentation and is performed without sacrificing any donor site and complex design. It was applied to four nipples in two nulliparous cases. For all four corrected inverted nipples, good results were obtained, and there have been no complications. There were no deformities of the nipples or the areolas after this procedure, and the surgical scars were inconspicuous.

Adult↗