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Biomedical subjects

N Isshiki

Publications and source records attributed to N Isshiki.

At least 55 records · Page 3Linked to original sources
PubMed1991

Special instruments for laryngeal framework surgery.

Thyroplasties involve a variety of delicate surgical techniques that affect the outcome decisively. In particular, opening a window in the thyroid cartilage, undermining around the window frame and fixation of a window plug in thyroplasty, and passing a suture through the muscular process and thyroid ala are some examples of difficult procedures. Several instruments were devised to facilitate such procedures. They include a special raspatory, an ultrasonic osteotome for cartilage cutting, a narrow polyvinyl tube for suture passing, a suture holder for passing through the muscular process, and a wound retractor for arytenoid adduction. These were found useful in minimizing soft tissue damage and in precise performance of the procedures.

Humans↗
PubMed1990

Laryngeal pacing in unilateral vocal cord paralysis. An experimental study.

In an attempt to remobilize a unilaterally paralyzed vocal cord, experiments were made in five adult dogs. Adduction of the paralyzed vocal cord for phonation in synchrony with the intact cord was achieved by electrical stimulation of the adductor muscles that was triggered by the signals from the cricothyroid muscle. The difference in the level of action potentials of the cricothyroid muscle between during phonation and during respiration was used for setting the threshold so as to differentiate phonation from respiration. Nearly synchronous movement of the two vocal cords thereby attained during phonation greatly improved the voice quality that was hoarse without the paced stimulation.

Action Potentials↗
PubMed1990

Clinical evaluation of a new bilayer "artificial skin" composed of collagen sponge and silicone layer.

A bilayer "artificial skin" composed of an outer layer of silicone and an inner sponge layer of collagen and chondroitin sulphate has been developed by modifying the technique proposed by Yannas et al. (1980). Following experimental successes, the "artificial skin" was applied clinically. It was placed on the skin defects of 10 patients. Three weeks after application the outer layer of silicone sheet was peeled off and thin split thickness skin was grafted onto the newly synthesised dermis-like tissue. Secondary skin grafts took perfectly in all cases and postoperative appearance was satisfactory.

Adolescent↗
PubMed1990

Influence of glycosaminoglycans on the collagen sponge component of a bilayer artificial skin.

A bilayer artificial skin composed of a silicone membrane and a collagen sponge layer containing glycosaminoglycans (GAGs) was first developed by Yannas and Burke. They reported that GAGs contained in the collagen sponge layer contributed to the function of the artificial skin. In an attempt to assess the effect of GAGs in the collagen sponge layer, the electron microscopic structure, mechanical strength of collagen sponges, and cell proliferation were examined in vitro, using four kinds of collagen sponges containing: no GAG, chondroitin 6-sulphate (C6S), dermatan sulphate (DER), and hyaluronic acid (HYA). The results indicated that: (1) addition of GAGs scarcely affected the mechanical structure of collagen sponges; (2) addition of C6S and DER reinforced mechanical strength, while addition of HYA did not; (3) addition of C6S and DER significantly decreased cell proliferation.

Artificial Organs↗
PubMed1990

Experimental study of a newly developed bilayer artificial skin.

A bilayer artificial skin composed of an outer layer of silicone polymer and an inner sponge layer of collagen containing chondroitin 6-sulphate was developed by modifying the technique proposed by Yannas et al. The artificial skin was placed on the skin defects on the backs of rats. Histological observation indicated that fibroblasts and capillaries infiltrated into the pores and filled in lattice spaces, resulting in synthesis of the connective tissue matrix and absorption of the original network of collagen and chondroitin 6-sulphate. Epidermal cells migrated from the edge of the wound between the two layers. Post-operative contracture in the wound with the artificial skin was significantly less than in the control.

Animals↗
PubMed1990

Distally based lateral calcaneal flap.

In our cadaver dissection, the connection between the lateral calcaneal artery, the lateral tarsal artery, and the branch of the lateral plantar artery was corroborated, indicating possible reverse blood flow in the lateral calcaneal artery. The distally based lateral calcaneal flap has been successfully used in 2 patients. Vascular anatomy, indication, and technical points of the surgery as well as advantages and disadvantages of the flap are discussed.

Adult↗
PubMed1990

Effects of lateral manual compression upon glottic incompetence: objective evaluations.

Forceful manual compression of the thyroid and cricoid cartilages modifies the position, shape, and tension of the vocal folds. This is the basis of the four laryngeal manual compression tests, adjunctive examinations used as a means of preoperative assessment of patients for medialization laryngoplasty, ie, Isshiki thyroplasty types I and IV and arytenoid adduction. The laryngeal manual compression tests are simple to perform and noninvasive. Each of the four examinations yields valuable information on the effects on the voice of changes in vocal cord characteristics produced by manual compression. In this report, one of the four tests, lateral manual compression, is evaluated objectively with well-attested methods of videostroboscopic, aerodynamic, and acoustic analysis. The technique of performing lateral manual compression is described, and advantages and disadvantages are noted and compared in 10 patients. Preliminary findings in 4 patients in this group indicate that medialization laryngoplasty should be considered when test results are conclusive of effective glottic closure. Data derived in this preliminary study will be augmented as patients are added to the series.

Adult↗
PubMed1990

Technique of total ear reconstruction with open framework, composite pseudomeatus graft, and postauricular transposition flap.

Modifications of Tanzer's technique of total reconstruction of the auricle are described, emphasizing the construction of a deep conchal cavity and pseudomeatus, with ample projection of the auricle. To obtain a more prominent projection of the auricle, a transposition flap from retroinfra-auricular skin is used, with placement of small cartilage props beneath the framework. The depth of the conchal cavity is enhanced by excavation of soft tissues and placement of an additional cartilage graft at the posterior wall of the choncha. The external meatus is imitated by a cone-shaped composite graft taken from the cymba of the opposite ear.

Child↗
PubMed1989

Significance of reactive oxygen species in distal flap necrosis and its salvage with liposomal SOD.

In an attempt to elucidate whether reactive oxygen species (ROS) have a role in causing distal necrosis of random pattern flaps, and to develop measures to prevent necrosis, three experiments were made using a rat flap model. The flap-salvaging effect of liposomal superoxide dismutase (L-SOD) was assessed. The results were as follows: (1) Measurements of changes in cutaneous blood flow in a flap, with time, revealed an initial remarkable decrease followed by gradual but significant increase in the distal portion 24 hours after operation. (2) The SOD activity in the flap continued to decrease gradually with time until 24 hours after operation both in L-SOD treated and control groups. However, SOD activity in L-SOD treated flaps was always significantly higher than in the control. (3) S-D value (survival length minus dye distance) was significantly greater in the L-SOD treated flap than in the control flap, indicating a significant effect of L-SOD in preventing the expected flap necrosis. These results suggest a possible role, in causing flap necrosis, of ROS which are generated by reperfusion following ischaemia, and the effectiveness of L-SOD in salvaging distal flap necrosis.

Animals↗
PubMed1989

Recent modifications in thyroplasty type I.

Among thyroplasties, type I is the most frequently used for medialization of the vocal cord. Follow-up study on patients indicated that reversion of voice can occur after operation. Revision was done in five cases with improvement of voice. On the basis of this experience, modifications were made in the technique of thyroplasty type I. They include 1) cutting the calcified cartilage with minimal intervention in the soft tissue, 2) fixation of the window with a silicone plug to enhance medialization, and 3) overmedialization of the vocal cord and definition of criteria for it that can be used during surgery.

Female↗
PubMed1988

Experimental study on "delay" phenomenon in relation to flap width and ischaemia.

The present investigation was designed to clarify what induces circulatory enhancement in the delay procedure. Two different sizes of a bipedicle flap were prepared in rats and the blood flow was measured at the centre of the flaps. The delay effect, that is, elongation of the survival length, was significantly less in the wide flap than in the narrow flap, though the two flap groups had almost identical levels of central ischaemia when averaged for each group. On the basis of ischaemic level, the flaps, regardless of size, were classified into two groups: more and less ischaemic than the mean. The delay effects noted in the more ischaemic flaps were not significantly different from those in the less ischaemic flaps. These results indicate that flap width has more influence on the delay effect than the degree of ischaemia.

Animals↗
PubMed1988

Repair of subglottic stenosis with a free perichondrial graft.

A case of tracheal stenosis was reconstructed, after trough formation, with a chondromucosal flap which was developed by submucous perichondrial grafting. At the first stage, a free perichondrial graft from the pinna was transplanted into the buccal submucosal layer. About 10 months later, when sufficient neocartilage had formed, the chondromucosal composite graft was transferred from the buccal region to the paratracheal subcutaneous region with the mucosa facing deeply. Finally, 4 weeks later the tracheal trough was closed with a composite rotation flap which incorporated the skin, neocartilage and mucosa. The postoperative course was uneventful and a wide tracheal lumen with a firm framework and mucous lining was confirmed by both fibrescopic and radiographic examination.

Cheek↗
PubMed1987

Distally based dorsalis pedis island flap for coverage of the distal portion of the foot.

A distally based dorsalis pedis island flap is described which has been successfully used for reconstructing the distal portion of the foot in two patients with amputation of all 5 toes. The indication for this flap is a wide skin defect of the distal half of the dorsal foot without history of local vascular disorder. The arterial inflow of the flap comes from the posterior tibial artery via the deep plantar branch of the dorsalis pedis artery, while the venous drainage is most likely to be through the venae comitantes of the dorsalis pedis artery to those of the deep branch.

Adult↗
PubMed1987

Effect of intravenous prostaglandin E1 on experimental flaps.

Prostaglandin E1 (PGE1) is a kind of prostaglandin that produces vasodilation of the peripheral vessels and platelet disaggregation, similar to prostacyclin (PGI2). The effects of PGE1 administered intraarterially or intravenously on peripheral vascular disease have been reported by many authors. In this investigation, 2 experiments were designed to assess the effect of intravenous infusion of PGE1 on the experimental skin flaps in rabbits. In the first experiment, the blood flow in the flap was measured before and after the administration of PGE1 by using the technique of clearance of hydrogen gas, which was generated by electrolysis. The result indicated a biphasic effect of PGE1 on the blood flow in the flap. That is, the low dose (3 micrograms per kilogram per hour) increased the blood flow on the critical line of the dye distance, while the high dose (20 micrograms per kilogram per hour) decreased it. The second experiment, in which the survival length was measured, indicated the practical effect of intravenous infusion of PGE1 on flap survival.

Alprostadil↗
PubMed1987

Long-term survival of a free split-thickness skin graft on a large seroma.

A free skin graft about 12 cm in diameter transplanted after excision of a Bowen's carcinoma on the back totally survived for a long period on seroma and was confirmed to have revascularization from the host skin margin. Repeated evacuations of the fluid and subsequent pressure dressings failed to cause adherence of the graft to the bed, even on the thirty-ninth postoperative day. Histologic examination of the graft and the bed revealed partial epithelialization on the face-to-face surfaces, to which no adherence was attributed. The incomprehensible phenomenon in this unusual clinical case evokes a new interest in the mechanism of free skin graft survival, particularly in the phase of serum imbibition.

Back↗
PubMed1987

The use of subcutaneous pedicle flaps in the treatment of postburn scar contractures.

Subcutaneous pedicle flaps, which were usually applied to repair small skin defects in the face or the fingertip, have been used with success in the treatment of 17 postburn scar contractures, with the exception of one partial flap necrosis. The results indicate the reliability and usefulness of this technique in the treatment of scar contractures, even in the extremities or the trunk. Subcutaneous pedicle flaps are effective for relatively wide contractures or quadratic contractures. When the skin tension across the contracture line is too great to use any local flap, such as a Z-plasty or V-Y plasty, the subcutaneous pedicle flap is particularly useful, because it can be freely designed in an area where the tension is small. When the flap contains some superficial scarring, the subcutaneous pedicle flap is preferred over other local flaps because of the superior vascularity and mobility.

Abdomen↗
PubMed1986

Surgical techniques for a deep concha, a pseudomeatus, and high projection in congenital microtia.

Some modified surgical techniques are described for constructing a deep conchal cavity and pseudomeatus and obtaining high auricular projection in congenital microtia. At the primary operation, a rather small portion of the microtic vestige is utilized for the lobule by switching, sparing the skin for the concha, with no free skin graft used. For higher projection of the auricle, three-dimensional transposition of a retroinfraauricular flap together with cartilage pieces underneath is applied to the cephaloauricular sulcus. A deep conchal cavity is constructed by further removal of the soft tissue there, transplantation of a cartilage for building a high posterior wall of the concha. The external meatus is successfully imitated by transplantation of a cone-shaped composite graft taken from the cymba of the opposite ear. The retroinfraauricular flap, the reconstruction of a deep concha, and the composite graft technique were successfully used in 55, 16, and 11 ears, respectively.

Cartilage↗