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Hirotaka Asato

Publications and source records attributed to Hirotaka Asato.

At least 19 recordsLinked to original sources
PubMed2006

Extensive actinomycosis of the face requiring radical resection and facial nerve reconstruction.

We present a case of extensive actinomycosis of the face, which appeared after dental surgery. Since antibiotic therapy was ineffective, the lesion was radically resected, and the skin, soft tissue and facial nerve were reconstructed using a free rectus abdominis musculocutaneous flap and simultaneously harvested intercostal nerves. Successful reanimation of the face was achieved 14 months postoperatively.

Actinomycosis↗
PubMed2006

Cartilage tissue engineering using human auricular chondrocytes embedded in different hydrogel materials.

To seek a suitable scaffold for cartilage tissue engineering, we compared various hydrogel materials originating from animals, plants, or synthetic peptides. Human auricular chondrocytes were embedded in atelopeptide collagen, alginate, or PuraMatrix, all of which are or will soon be clinically available. The chondrocytes in the atelopeptide collagen proliferated well, while the others showed no proliferation. A high-cell density culture within each hydrogel enhanced the expression of collagen type II mRNA, when compared with that without hydrogel. By stimulation with insulin and BMP-2, collagen type II and glycosaminoglycan were significantly accumulated within all hydrogels. Chondrocytes in the atelopeptide collagen showed high expression of beta1 integrin, seemingly promoting cell-matrix signaling. The N-cadherin expression was inhibited in the alginate, implying that decrease in cell-to-cell contacts may maintain chondrocyte activity. The matrix synthesis in PuraMatrix was less than that in others, while its Young's modulus was the lowest, suggesting a weakness in gelling ability and storage of cells and matrices. Considering biological effects and clinical availability, atelopeptide collagen may be accessible for clinical use. However, because synthetic peptides can control the risk of disease transmission and immunoreactivities, some improvement in gelling ability would provide a more useful hydrogel for ideal cartilage regeneration.

Atrial Appendage↗
PubMed2006

Hepatic artery reconstruction with double-needle microsuture in living-donor liver transplantation.

In living-donor liver transplantation (LDLT), reconstruction of the hepatic artery is challenging because the recipient artery is located deep in the abdominal cavity and the operating field is limited. Also, the hepatic artery of the graft is short and the recipient artery is occasionally damaged. To overcome these difficulties, we developed a double-needle microsuture technique for artery reconstruction. A total of 161 adult patients received 163 LDLTs using this new technique. The first suture was placed at the most difficult point in the artery to be visualized through the microscope. Each stitch was placed from the inner side of the arterial wall to the outer side. The posterior stitch was tied pulling toward the back. The subsequent sutures were advanced anteriorly on either side adjacent to the previous suture. Hepatic artery thrombosis occurred in 4 patients (2.5%), only 2 (1.2%) of which were associated with arterial reconstruction. Intimal dissection developed in the recipient artery in 2 patients (1.2%). Three (50%) of these 6 complications occurred more than 10 days after LDLT. In conclusion, this suturing technique allows for safe intimal adaptation even when the arterial tunica intima is separated from the tunica media, because all stitches are carried from inside of the vessel to the outside, contributing to more satisfactory results.

Adult↗
PubMed2006

One-stage reconstruction of facial paralysis associated with skin/soft tissue defects using latissimus dorsi compound flap.

Neurovascular free muscle transfer is now the mainstay for smile reconstruction in the treatment of established facial paralysis. Since facial paralysis due to ablative surgery or some specific disease sometimes accompanies defects of the facial skin and soft tissue, simultaneous reconstruction of defective tissues with facial reanimation is required. The present paper reports results for 16 patients who underwent reconstruction by simultaneous soft tissue flap transfer with latissimus dorsi muscle for smile reconstruction of the paralysed face. Soft tissue flaps comprised skin paddle overlying the latissimus dorsi muscle (n=6), serratus anterior musculocutaneous flap (n=5), serratus anterior muscle flap (n=2), and latissimus dorsi perforator-based flap with a small muscle cuff (n=3). The latissimus dorsi muscle can be elevated as a compound flap of various types, and thus offers the best option as a donor muscle for facial reanimation when soft tissue defects require simultaneous reconstruction.

Adolescent↗
PubMed2006

Volumetric changes in the transferred flap after anterior craniofacial reconstruction.

The goal of craniofacial reconstruction is not only life-saving but also facial aesthetics. From this viewpoint the authors evaluated the facial symmetry of patients after craniofacial reconstruction. The subjects were seven patients reconstructed after craniofacial resections. Their CT or MR images were evaluated just after surgery, 1 month after surgery, and 6 months after surgery. Based on these images, the proportion of simple area (PSA) and the proportion of overlapped area (POA) were calculated. The PSA is the proportion of the reconstructed quarter to the contralateral one, and the POA is the proportion of the overlapped area in the reconstructed quarter to the normal one. These values were assessed in two groups: five patients without and two with split calvarial bone grafts. Results demonstrated that the volumetric change of the reconstructed face with the bone graft was relatively stable.

Adolescent↗
PubMed2006

Clinical evaluation and morbidity of 201 free jejunal transfers for oesophagopharyngeal reconstruction during the 20 years 1984-2003.

We evaluated 192 patients who had 201 free jejunal transfers for oesophagopharyngeal reconstruction during the 20 years 1984-2003. The main postoperative complications were thrombosis, leaks, and stenosis. In this series, the rate of thrombosis was 7/201 (3.5%), that of leaks was 17/201 (8.5%), and that of stenosis was 25/201 (13.0%). When we assessed the relation between pre-existing conditions, surgical techniques, and these complications, we found only one significant difference: a history of alcohol misuse was associated with a reduction in the incidence of thrombosis. The surgical techniques did not affect the development of leaks or stenosis, which means that a complicated surgical technique is unnecessary.

Adult↗
PubMed2006

Availability of end-to-side arterial anastomosis to the external carotid artery using short-thread double-needle microsuture in free-flap transfer for head and neck reconstruction.

We seldom have difficulties in the selection of appropriate recipient arteries for microvascular free flap transfer in the head and neck region because many sizable branches (branch artery) of the external carotid artery (ECA) or subclavian artery are available. However, we occasionally encountered the lack of an appropriate recipient artery, especially in secondary reconstruction or reconstruction following the extensive ablation of recurrent cancer. For these challenging cases, we have used end-to-side arterial anastomosis directly to the ECA. Between July 1997 and December 2004, end-to-side anastomosis of the flap artery to the ECA was employed in 16 cases. The reason for its use included the marked size discrepancy between the jejunal artery and branch artery in 4 jejunal transfer cases, the lack of 2 appropriate recipient arteries for double free flap transfers in 1 case, and the lack of an available branch artery as a recipient due to poor regional conditions in 11 cases. Fifteen of 16 flaps underwent an uneventful postoperative course, except 1 whose flap artery was pressed by the submandibular gland and sustained thrombosis 3 days postoperatively. In this case, however, the flap survived perfectly after prompt thrombectomy and reanastomosis. Eventually, all 16 flaps survived completely. We reconfirmed the availability of end-to-side anastomosis to the ECA when a suitable branch artery is not available. Although end-to-side anastomosis to the ECA is laborious compared with end-to-end anastomosis, our newly developed short-thread double-needle microsuture combined with the back-wall-first technique helps to ensure easier anastomosis. Using this device, because all stitches are carried from inside the vessel to outside, the surgeon can place the first stitch at any point on the posterior wall and advance the next suture to the preferred site of the previous suture, and suturing can be performed more safely even in cases where the tunica intima is separated from the tunica media due to arteriosclerosis, previous irradiation, or surgery.

Adolescent↗
PubMed2005

Choice of osseous and osteocutaneous flaps for mandibular reconstruction.

Microvascular free flap transfer currently represents one of the most popular methods for mandibular reconstruction. With the various free flap options now available, there is a general consensus that no single kind of osseous or osteocutaneous flap can resolve the entire spectrum of mandibular defects. A suitable flap, therefore, should be selected according to the specific type of bone and soft tissue defect. We have developed an algorithm for mandibular reconstruction, in which the bony defect is termed as either "lateral" or "anterior" and the soft-tissue defect is classified as "none," "skin or mucosal," or "through-and-through." For proper flap selection, the bony defect condition should be considered first, followed by the soft-tissue defect condition. When the bony defect is "lateral" and the soft tissue is not defective, the ilium is the best choice. When the bony defect is "lateral" and a small "skin or mucosal" soft-tissue defect is present, the fibula represents the optimal choice. When the bony defect is "lateral" and an extensive "skin or mucosal" or "through-and-through" soft-tissue defect exists, the scapula should be selected. When the bony defect is "anterior," the fibula should always be selected. However, when an "anterior" bone defect also displays an "extensive" or "through-and-through" soft-tissue defect, the fibula should be used with other soft-tissue flaps. Flaps such as a forearm flap, anterior thigh flap, or rectus abdominis musculocutaneous flap are suitable, depending on the size of the soft-tissue defect.

Bone Transplantation↗
PubMed2005

Double vascular pedicled free jejunum transfer for total esophageal reconstruction.

A double vascular pedicled free jejunum was transferred in two patients with complete esophageal defect. When the stomach and colon, which are usually employed for esophageal reconstruction, cannot be used due to previous operations or for other reasons, the jejunum is the next alternative. However, pedicled jejunal transposition is limited in length and may not reach a suitable level over the lower cervical esophagus, even if the distal portion is supercharged. Under such circumstances, a long jejunal segment with two vascular pedicles can be transferred as a free flap and used to reconstruct the whole esophagus in one stage. The paper describes two cases and discusses the advantages of double vascular pedicled free jejunum transfer.

Aged↗
PubMed2005

Posterior tibial adiposal flap for repair of wide, full-thickness defect of the Achilles tendon.

Wide, full-thickness defects on the posterior aspect of the distal lower leg involving the Achilles tendon are usually repaired with free fasciocutaneous flaps or local skin flaps. The former require microvascular techniques; there is a donor-site scar due to skin grafting; and a longer operating time. The latter results in a wide scar near the donor defect. The authors developed a new reconstructive procedure using local fascia turned over to create a new Achilles tendon, and wrapping it with a posterior tibial adiposal island flap based on the dominant perforator of the posterior tibial artery, which was elevated from the medial aspect of the lower leg. The advantages of this method are that no donor scar appeared on the posterior aspect of the lower leg, and there was no need for microvascular techniques. This method is especially suitable for young women.

Achilles Tendon↗
PubMed2005

Craniofacial anomalies of the cultured mouse embryo induced by inhibition of sonic hedgehog signaling: an animal model of holoprosencephaly.

The pathogenesis of holoprosencephaly is multifactorial, and blockage of Sonic hedgehog signaling is one of the most important causative factors in animal models and human cases. In this study, the authors analyzed facial anomalies of mouse embryos, which were cultured in vitro and exposed to cyclopamine, an alkaloid blocker of Sonic hedgehog signaling. When cultured with cyclopamine for embryonic day 8.5 to 10.5, the whole body size was smaller than normal, and the distance and angle between the nasal placodes were remarkably reduced. Extension of the cranial surface vessels also was noted. No cyclopia was observed. Migration of the cranial neural crest cells seemed to be intact. Expressions of Patched-1 and Gli-1, downstream genes of Sonic hedgehog signaling, also were down-regulated in in situ hybridization and real-time reverse transcriptase-polymerase chain reaction analyses. The authors consider that these facial anomalies represent milder phenotypes of holoprosencephaly.

Animals↗
PubMed2005

Revisional operations improve results of neurovascular free muscle transfer for treatment of facial paralysis.

BACKGROUND: Neurovascular free muscle transfer is currently the mainstay for smile reconstruction. However, problems such as excessive muscle bulk and dislocation of the transferred muscle attachment have been described. Furthermore, dynamic movements of the transferred muscle are sometimes too strong or too weak, resulting in facial asymmetry. In these cases, secondary revisional operations for the transferred muscle are required after neurovascular free muscle transfer. This report describes revisional operative procedures in detail and examines the extent of improvement of the smile by comparing preoperative and postoperative results. METHODS: Of 468 patients in whom neurovascular free muscle transfer was performed between 1977 and 2000, a total of 183 received revisional operations for the transferred muscle. Operations included revision of muscle attachment in 129 patients, debulking of the cheek in 114 patients, and fascia graft in 21 patients. RESULTS: Evaluation with the grading scale was performed in 117 of the 183 patients. Grading improved in 59 patients and worsened in seven patients. The remaining 51 patients displayed no change in grading. Differences between preoperative and post-operative grading were compared statistically, and revisional operations improved the grading score. CONCLUSIONS: Revisional operations are effective and important as secondary operations after neurovascular free muscle transfer. However, care must be taken not to damage the neurovascular pedicles.

Adult↗
PubMed2005

Secondary reconstruction of failed esophageal reconstruction.

Between June 1992 and November 2002, 17 patients underwent secondary reconstruction of circumferential esophageal defects due to the failure of immediate reconstruction following ablation of thoracic esophageal cancer. Salvage reconstruction was achieved using free jejunal transfer in 13 patients (including long segment with double vascular pedicle in 2 cases), skin and/or musculocutaneous flap in 2 cases, and jejunal pull-up in 2 cases. In 5 patients, the second salvage surgery was required because of the failed first salvage. However, successful restoration of the esophagus and peroral alimentation was finally achieved in 16 of 17 patients, except 1 patient with several salvage operations using skin and musculocutaneous flap because the gut was unusable. We concluded that the preferred first choice for salvage restoration is free jejunal transfer. If the length of the esophageal defect is extensive, colonic interposition or jejunal pedicle with microvascular anastomosis for supercharging is the next option. If these procedures cannot be used, the transfer of a long jejunal segment with double vascular pedicles is recommended. Reconstruction using skin and/or musculocutaneous flap is the final option. As primary wound closure is often difficult in secondary reconstruction of the esophagus, a pectoralis major musculocutaneous flap is reliable to cover the reconstructed esophagus because skin flaps located in the neck region may be damaged by neck dissection or irradiation, and coverage of the anastomosis with muscle between the digestive tracts is effective to prevent leakage.

Aged↗
PubMed2005

A revised method for pharyngoesophageal reconstruction using free jejunal transfer.

Pharyngoesophageal reconstruction using free jejunal transfer is a reliable procedure, but the achievement of perfect functional results is still challenging. We present a devised method. Jejunoesophageal anastomosis is performed after 2 longitudinal incisions are made at the side corners of the esophageal stump. This maneuver not only enlarges the size of the esophageal stump but also provides a "Z-plasty-like" effect, which reduces the risk of delayed stricture formation. The pharyngojejunal anastomosis is performed in an end-to-end manner. Irrespective of the highest point of the pharyngeal defect, a longitudinal incision is made at the edge of the jejunal graft corresponding to the midpoint of the back wall of the pharyngeal stump. With this concept, considerable longitudinal tension is placed on the posterior side of the jejunal graft, whereas moderate tension is placed on the anterior side of the graft, which prevents the fistula formation that tends to occur in the anterior suture line. Twenty patients underwent the reconstruction using this operative procedure. In all cases, postoperative deglutition was satisfactory without jejunal redundancy or constriction. We believe that our method can be applied in most cases of pharyngoesophageal defects, providing simple and reasonable reconstruction using free jejunal transfer with stable results.

Aged↗
PubMed2005

Synergistic effects of FGF-2 with insulin or IGF-I on the proliferation of human auricular chondrocytes.

Chondrocyte preparation with the safety and efficiency is the first step in cartilage regenerative medicine. To prepare a chondrocyte proliferation medium that does not contain fetal bovine serum (FBS) and that provides more than a 1000-fold increase in cell numbers within approximately 1 month, we attempted to use the medium containing 5% human serum (HS), but it exerted no more than twofold increase in 2 weeks. To compensate for the limited proliferation ability in HS, we investigated the combinational effects of 12 factors [i.e., fibroblast growth factor (FGF)-2, insulin-like growth factor (IGF)-I, insulin, bone morphogenetic protein-2, parathyroid hormone, growth hormone, dexamethasone, 1alpha25-dihydroxy vitamin D3, L-3,3',5'-triodothyronine, interleukine-1 receptor antagonist, 17beta-estradiol, and testosterone] on the proliferation of human auricular chondrocytes by analysis of variance in fractional factorial design. As a result, FGF-2, dexamethasone, insulin, and IGF-I possessed promotional effects on proliferation, while the combination of FGF-2 with insulin or IGF-I synergistically enhanced the proliferation. Actually, the chondrocytes increased 7.5-fold in number in 2 weeks in a medium containing 5% HS with 10 ng/ml FGF-2, while the cell number synergistically gained a 10-12-fold increase with 5 microg/ml insulin or 100 ng/ml IGF-I in the same period. The proliferation effects were more enhanced at a concentration of 100 ng/ml for FGF-2, and especially for the combination of 100 ng/ml FGF-2 and 5 microg/ml insulin (approximately 16-fold within 2 weeks). In the long-term culture with repeated passaging, this combination provided more than 10,000-fold within 8 weeks (i.e., passage 4). Thus, we concluded that such a combination of FGF-2 with insulin or IGF-I may be useful for promotion of auricular chondrocyte proliferation in a clinical application for cartilage regeneration.

Adolescent↗
PubMed2004

Hepatic arterial anatomy for right liver procurement from living donors.

Living donor liver transplantation (LDLT) using right liver grafts is now widely performed. Anatomic classifications of the hepatic artery for right liver procurement, however, are limited. In this study, celiac and mesenteric angiograms of 223 consecutive living donors in a single institution were evaluated. Details of the arterial anastomosis and results were reviewed in 72 patients who underwent primary LDLT using right liver grafts. There was a 6% incidence of hepatic arterial bifurcations that might provide multiple orifices in a right liver graft. Only one right liver graft (1%) had multiple arterial orifices. Single arterial anastomosis without interposition was possible in all patients with right liver grafts and none of them were complicated with hepatic arterial thrombosis. Single arterial anastomosis, therefore, has a high probability of success in right liver graft implantation.

Adolescent↗