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Biomedical subjects

Y Hirase

Publications and source records attributed to Y Hirase.

At least 19 recordsLinked to original sources
PubMed1997

Salvage of fingertip amputated at nail level: new surgical principles and treatments.

In this study, a new classification of fingertip amputation based on the surgical treatment is reported. Specifically, the necessity for special procedures to prevent venous congestion in fingertip replantation at the nail bed level was studied. There are some reports of successful replantations without venous anastomoses. In order to avoid technical factors, clinical cases operated on by a single surgeon were evaluated to determine what treatment is necessary for amputations at various levels to avoid necrosis due to venous congestion. During the 5-year period from October 1987 to October 1992, 150 replantations in 137 patients were performed, including 49 fingertip replantations in 45 patients who were operated on consecutively by a single surgeon. The distal phalanx (DP) of the finger was classified as zone DP-I, IIA, IIB, and III from distal to proximal. This classification was based not only on the amputation level but also on the difference in surgical treatment. For amputations of zone DP-I, which extends from the fingertip to the most distal dividing point of the digital artery, the amputated fingertip is attached without vascular anastomosis and the whole finger is wrapped in aluminium foil and cooled in ice water for 3 days. For amputations of zone DP-IIA and IIB, anastomosis of the digital artery is performed in the central portion of the palmar region of the finger, but Kirschner wire fixation is not performed so as not to disturb the venous drainage through the medullary cavity. For amputations of zone DP-IIA, special treatment is not necessary for venous congestion, and for those of zone DP-IIB partial resection of the nail is done if necessary. For zone DP-II amputations, venous anastomosis must be performed for salvage. All patients were operated on according to the procedures based on this classification and final survival rate was 91.5%.

Adult↗
PubMed1996

Long-term cryopreserved allogeneic nervous and vascular tissue transfers in monkeys.

Four adult Japanese monkeys were used. Donor tissues were harvested from the radial artery, saphenous vein and median nerve, 10 cm in length, and cryopreserved at -196 degrees C in a stepwise manner for long-term preservation for more than 6 months. After rapid thawing of the tissue, the allogeneic tissue transfer was performed of the radial artery to the radial artery, the saphenous vein to the ulnar artery and the median nerve to the median nerve between male and female monkeys. After one year follow-up, angiography was performed and the transferred tissue was harvested for scanning electron microscopic examination and histological examination. As a result, the allogeneic artery in the radial artery was completely patent with no stenosis, whereas there was obstruction of the allogeneic vein in the ulnar artery. Good axonal recovery of the median nerve was observed on histological examination. The cellular structure of neurovascular tissue can be maintained even after long-term cryopreservation. The antigenicity of tissue may be reduced significantly by being frozen, and cryopreserved allogeneic artery can be transferred successfully without the use of immunosuppressive agents. In this report, clinical aspects and the great potential of allogeneic neurovascular tissue transfer, especially in combination with arterial transfer, using cryopreservation are discussed.

Animals↗
PubMed1994

Experimental study of cryopreserved allogeneic transfer of vessel: preliminary report.

It has long been known that the antigenicity of tissues is depressed when they are kept at a very low temperature. In this study, Lewis rats and Brown Norway (B.N.) rats were used because these species are significantly dissimilar at the major histocompatibility complex (MHC) Femoral arteries were harvested from Lewis rats, frozen while lowering the temperature in a stepwise fashion to -70 degrees C. After three weeks of cryogenic storage, the arteries were transplanted into Lewis and B.N. rats. At various times from the first to the twelfth week after surgery, grafted vessels were observed, and pathological and electron microscopic studies were carried out. The vessels were found to be in good condition at the end of the 12 week observation period. These results strongly suggest that prolonged cryopreservation of vessels makes allotransplantation without immunosuppression possible.

Animals↗
PubMed1994

Extended palmar advancement flap with V-Y closure for finger injuries.

The technique of using volar advancement flaps with V-Y closure to the fingers is described. It is possible to perform volar flap advancements up to 15 mm and use V-Y closures in the distal palm, avoiding a skin graft. This method is based on knowledge of the vascular anatomy of the finger dorsum, to avoid devitalising dorsal skin. This method was applied to 14 fingers of 13 patients including finger amputations, claw nail deformities, and skin defects of the middle phalanx. Favourable results were observed.

Adolescent↗
PubMed1994

Secondary correction of the bilateral cleft lip nose by excision of the columellar forked flap and nasal remodelling with reverse-U flaps: a preliminary report.

Although the forked flap procedure has been widely used as a technique to lengthen the columella in the bilateral cleft lip deformity, often the results are unfavourable. We describe a technique to achieve a more natural shape, in which the unsatisfactory forked flap is excised and the columella is reconstructed by mobilization and rotation of nasal skin, combined with bilateral reverse-U flaps. Five consecutive patients who underwent this secondary correction procedure are presented.

Adolescent↗
PubMed1993

A combination surgical method for preaxial polydactyly of the foot.

A combination procedure was performed on the medial two toes in a 6-month-old child with preaxial polydactyly of the left foot. The first toe had the appearance of a cosmetically intact great toe, but the second toe had better function. A method to combine the advantages of these two toes was therefore applied, with favorable results seen at 1.5 years after surgery.

Follow-Up Studies↗
PubMed1993

Complete congenital duplication with incomplete separation of a lower extremity.

A case of a boy with complete duplication of the lower extremity and separation below the lower leg was described. Although x-ray examination revealed no femur, operation revealed a cartilage expected to become the femur in the future. A classification of duplication and separation of the lower extremity is proposed. The method and course of treatment in the present case were described in detail, including the application of tissue expanders on the deformity of the knee joint accompanied by a shortening of the sciatic nerve.

Congenital Abnormalities↗
PubMed1992

Microsurgical use of polydioxanone (PDS) suture: an experimental report.

Although many technological advances have been made in surgical materials, nylon is still the main suture material use for microvascular surgery. This study sought to evaluate polydioxanone (PDS) sutures for use in microvascular anastomoses. Twenty-eight male Sprague-Dawley rats were used in this experiment. Spatula-type needles with 9-0 PDS suture were used to anastomose the right femoral arteries, with 9-0 nylon used on the left side. The arteries were observed for 1, 2, 3, 4, 8, 12, and 16 weeks after surgery to determine arterial patency and to evaluate vascular pathology. Results were comparable between PDS and nylon. We suggest that if the suture material is redesigned to allow smooth passage through the tissue, and if the needle used in conjunction with the suture is improved, PDS may offer an excellent material for microvascular anastomosis.

Anastomosis, Surgical↗
PubMed1992

Clinical characteristics of vascular leiomyoma of the upper extremity: report of 11 cases.

Clinical features of vascular leiomyoma of the upper extremity which have not been described or have been described incorrectly are documented with a report of 11 consecutive cases seen within the past 11 years. All patients were followed without recurrence or surgical morbidity. Vascular leiomyoma has been described as a painful nodule found more frequently on the extensor surfaces, but in our experience spontaneous or paroxysmal pain is exceptional and the tumour tends to be located on the volar surface when it is in the hand. In the digit, they tend to be found at the base away from the midline, and not seen distal to the DIP joint.

Adolescent↗
PubMed1992

Vascular anatomy of the finger dorsum and a new idea for coverage of the finger pulp defect that restores sensation.

The cutaneous vascular anatomy of the finger dorsum was studied by dissection under loupe magnification of 71 fingers from 19 preserved cadaver hands. All specimens were injected with red latex or epoxy resin through a cannula in the brachial artery to identify the small vessels. The finger dorsum was supplied by the terminal branches from the dorsal metacarpal artery around the metacarpophalangeal joint. Other areas were nourished by the dorsal cutaneous branch from the proper palmar digital artery. There were two or three dorsal branches in the proximal phalangeal region and two in the middle phalangeal region. On the basis of these findings, we have developed a new method for one-stage reconstruction of finger pulp defect that restores sensation. Our innervated reverse vascular pedicle digital island flap includes the dorsal digital nerve and the proper palmar digital artery as a retrograde vascular pedicle. We have used the technique in three patients, with excellent results. The advantage of this procedure is that it provides a one-stage reconstruction of the pulp defect and restores sensation. The disadvantage is that the procedure requires neurorrhaphy.

Adult↗
PubMed1991

Methanol in urine as a biological indicator of occupational exposure to methanol vapor.

The exposure-excretion relationship and possible health effects of exposure to methanol vapor were studied in 33 exposed workers during the second half of 2 working weeks. Urinary methanol concentrations were also determined in 91 nonexposed subjects. The geometric mean value for methanol in urine samples from the latter was less than 2 mg/l (95% upper limit of normal, less than 5 mg/l) when log-normal distribution was assumed. Among the exposed workers, the methanol level in urine samples collected prior to the work shift exceeded the 95% upper limit of normal. The time-weighted average intensity of exposure to methanol vapor was measured using personal sampling devices (in which water severed as an absorbent) in 48 cases of methanol exposure (i.e., 2 of the 33 exposed workers failed to provide urine samples, whereas 17 subjects were examined twice). Methanol concentrations in urine were determined in samples collected at the end of the shift from the 48 exposed cases as well as from 30 nonexposed controls. There was a significant correlation between the exposure to methanol vapor at concentrations of up to 5,500 ppm and the levels of methanol measured in the shift-end urine samples. The calculation indicated that a mean level of 42 mg methanol/l urine (95% confidence range, 26-60 mg/kg) was excreted in the shift-end urine sample following 8 h exposure to methanol at 200 ppm (the current occupational exposure limit). Dimmed vision and nasal irritation were among the most frequent symptoms complained during work. Three cases showing clinical signs of borderline significance were identified.

Adult↗
PubMed1991

Long-term follow-up of a patient with lateral calcaneal flaps for bilateral posterior heel necrosis.

Lateral calcaneal flaps were used to cover the skin necrosis of bilateral posterior heels, and a favorable result was obtained. During the first 5 years after surgery, the patient enjoyed hiking as before and made favorable progress, having no trouble in the region covered with the flap and attaining sensory cortical reorientation soon after surgery. Paresthesia of donor sites was reduced in its extent and caused no difficulties in everyday life, but it remained after the lapse of 5 years. The medical record of this patient during the 5 years is reviewed, and we discuss the indications of a lateral calcaneal flap.

Burns↗
PubMed1991

Subcutaneous pedicle hypothenar island flap.

The status of the blood supply to the hypothenar skin was investigated by anatomical and radiological studies. The investigation revealed that the hypothenar skin receives a rich blood supply from the arterial network by branches from the palmar ulnar artery of the little finger and the hypothenar branches. By making use of this abundance of vascular networking, a subcutaneous pedicle flap was obtained from this site. This method was clinically applied to 7 patients, and the procedures and advantages of the method are described.

Adolescent↗
PubMed1991

Composite reconstruction for chest wall and scalp using multiple ribs-latissimus dorsi osteomyocutaneous flaps as pedicled and free flaps.

A composite flap is presented based on the latissimus dorsi myocutaneous unit together with the underlying ninth to eleventh ribs. Three patients are presented. In two, a full-thickness chest-wall defect was present. In one, a full-thickness scalp and cranial defect was present. Use of the composite osteomyocutaneous latissimus dorsi free flap as a pedicled flap in two patients and as a free flap in one patient resulted in successful definitive reconstruction in all with no complications. This procedure necessitates no transplantation of soft tissue prior to bone grafting to maintain local vascularity, so the simultaneous one-stage reconstruction of an osseous-soft-tissue defect becomes possible easily.

Adult↗
PubMed1991

Double-layered free temporal fascia flap as a two-layered tendon-gliding surface.

We report the use of a two-layered free fascial flap consisting of temporoparietal and deep temporal fascia based on a single vascular pedicle, the superficial temporal artery and vein. The flap was used to reconstruct an extensive degloving injury of the dorsum of the hand, in which multiple intact extensor tendons lay fully exposed on all sides, with exposed bone beneath them. By sandwiching the tendons between the layers of vascularized fascia, gliding surfaces were provided, both superficial and deep to the exposed tendons. The single-stage reconstruction was completed with a split-thickness skin graft. The patient returned to heavy manual work within 12 weeks of injury. He obtained an excellent range of movement without the need for tenolysis.

Adult↗
PubMed1990

Secondary ear reconstruction using deep temporal fascia after temporoparietal fascial reconstruction in microtia.

As anatomical study of the temporoparietal fascia (TPF) has advanced, there have been several reports on one-stage reconstruction of microtia using the TPF. To our knowledge, however, no report has described how to do secondary reconstruction if partial necrosis occurs, exposing the cartilage frame. Recently we treated a case of microtia that had become partially necrotic after the patient underwent one-stage reconstruction using the TPF. The deep temporal fascia was elevated to cover the necrotic portion and ensure successful placement of the skin graft. This technique greatly enhances one-stage reconstruction of the auricle using a TPF flap.

Adult↗