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Search Results: 1 - 10 of 420 matches for " Yukihide Iwamoto "
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The 45-Degree Arthroscope Improves Visualization of the Femoral Attachment of the Anterior Cruciate Ligament  [PDF]
Ken Okazaki, Shuichi Matsuda, Yasutaka Tashiro, Yukihide Iwamoto
Surgical Science (SS) , 2012, DOI: 10.4236/ss.2012.31007
Abstract: Background: Exposure of the insertion site of the anterior cruciate ligament (ACL) is important for appropriate tunnel placement in ACL reconstruction surgery. However, observing the femoral ACL insertion site via the standard anterolateral portal is sometimes difficult. In this study, we compared views of the femoral ACL insertion site between 30-degree and the 45-degree arthroscopes. Methods: We first inserted the 30-degree and the 45-degree arthroscope into the anterolateral portal of a knee simulator in which we had drawn a lattice pattern on the lateral intercondylar notch based on the quadrant method. Next, we compared the arthroscopic views provided by the 30-degree and 45-degree arthroscopes during ACL reconstruction surgery by measuring the area of the lateral intercondylar notch visible through each of the arthroscopes. Results: In the knee simulator, the 45-degree arthroscope showed the entire area of the lateral intercondylar notch, whereas the 30-degree arthroscope had to be introduced more deeply to show the most superior and posterior quadrant, where the attachment of the anteromedial bundle of ACL is located. During the ACL reconstruction, the area of the lateral intercondylar notch in the field of view was larger through the 45-degree arthroscope than through the 30-degree arthroscope. Conclusion: The 45-degree arthroscope provides a better view of the femoral ACL insertion site via the anterolateral portal, which may be helpful during ACL reconstruction.
Mutation analysis of the Gadd45 gene at exon 4 in atypical fibroxanthoma
Akio Sakamoto, Shizuka Akieda, Yoshinao Oda, Yukihide Iwamoto, Masazumi Tsuneyoshi
BMC Dermatology , 2009, DOI: 10.1186/1471-5945-9-1
Abstract: Immunohistochemical expression of Bax was analyzed in 7 cases of AFX, and in 7 cases of benign fibrous histiocytoma (BFH) used as a comparison. The expression pattern of Bax was compared to previously reported p53 and Gadd45 expressions in a correspondent series. Mutation of the Gadd45 gene at exon 4 was also analyzed in AFX.AFX and BFH showed immunoreactivities respectively for Bax (3/7, 0/7), Gadd45 (4/7, 1/7) and p53 (2/7, 0/7). There was no exact correlation between p53 expression and Bax or Gadd45 expression. However, the pattern of expression between Bax and Gadd45 was also the same, with the exception of one case. No mutation of the Gadd45 gene at exon 4 was observed in a series of 6 AFX cases where DNA was available (0/6).These results suggest a possible association between Bax and Gadd45 in AFX, and may refute any possibility of dysfunction of Gadd45 in terms of gene mutation, at least at exon 4 of the Gadd45 gene.Atypical fibroxanthoma (AFX) is a nodular ulcerative lesion arising from the sun-exposed skin of the head and neck, typically in the elderly [1,2]. Solar elastosis associated with UV-radiation has been commonly observed in AFX cases [3]. Association between AFX and ultraviolet (UV) radiation has been suspected. On the other hand, in its less common forms with weakened association with UV, AFX occurs on the extremities and the trunk [1,2]. AFX is composed of spindle, plump, epithelioid and bizarre cells, in various proportions, arranged in haphazard, vaguely fascicular or storiform patterns. These histological features of AFX mimic those of high-grade sarcoma, such as malignant fibrous histiocytoma or leiomyosarcoma [2,4], which occurs deep within soft tissue.The tumor-suppressor protein p53 is a transcriptional activator which is involved in cell-cycle control, DNA repair, apoptosis and chromosome/genome instability. UV-induced p53 gene mutations occurring at dipyrimidine sites have been demonstrated in AFX, suggesting a central role for UV radiat
Establishment of an animal model of a pasteurized bone graft, with a preliminary analysis of muscle coverage or FGF-2 administration to the graft
Tatsuya Yoshida, Akio Sakamoto, Nobuaki Tsukamoto, Koichi Nakayama, Yukihide Iwamoto
Journal of Orthopaedic Surgery and Research , 2009, DOI: 10.1186/1749-799x-4-31
Abstract: Forty pasteurized intercalary bone grafts of the Wistar rat femur treated at 60°C for 30 min were reimplanted and stabilized with an intramedullary nail (1.1 mm in diameter). Some grafts were not covered by muscle after the implantation, so that they could act as a clinical model for wide resection, and/or these were soaked with FGF-2 solution prior to implantation. The grafts were then divided into 3 groups, comprising 12 grafts with muscle-covering but without FGF-2 (MC+; FGF2-), 12 grafts without muscle-covering and without FGF-2 (MC-; FGF2-) and 16 grafts without muscle covering but with FGF-2 (MC-; FGF2+).At 2 weeks after grafting, the pasteurized bone model seemed to be successful in terms of eliminating living cells, including osteocytes. At 4 weeks after grafting, partial bone incorporation was observed in half the (MC+; FGF2-) cases and in half the (MC-; FGF2+) cases, but not in any of the (MC-; FGF2-) cases. At 12 weeks after grafting, bone incorporation was seen in 3 out of 4 in the (MC+; FGF2-) group (3/4: 75%) and in 3 out of 8 in the (MC-; FGF2+) group (3/8: 38%). However, most of the grafted bones without FGF-2 were absorbed in all the cases, massively, regardless of whether there had been muscle-covering (MC+; FGF2-; 4/4: 100%) or no muscle-covering (MC-; FGF2-; 4/4: 100%), while bone absorption was noted at a lower frequency (2/8: 25%) and to a lower degree in the (MC-; FGF2+) group.In conclusion, we have established an animal pasteurized bone graft model in rats. Pasteurized bone was able to maintain bone induction ability. Despite the low number of cases in each group, the results of each group suggest that muscle-covering has an effect on bone incorporation, but that it is not able to prevent bone absorption to the pasteurized bone. However, an application of FGF-2 may have a positive effect on bone incorporation and may be able to prevent bone absorption of the graft in cases of pasteurized bone graft.Pasteurized bone grafting is a method of hea
Nonossifying fibroma presenting as an aneurysmal bone cyst: a case report
Sakamoto Akio,Ishii Takeaki,Oda Yoshinao,Iwamoto Yukihide
Journal of Medical Case Reports , 2012, DOI: 10.1186/1752-1947-6-407
Abstract: Introduction Nonossifying fibroma is a common fibrous bone lesion in children that occurs in the metaphysis of the long bones of the lower extremities. The lesion rarely leads to aneurysmal bone cyst, which is characterized as a blood-filled space. Case presentation We present the case of a 13-year-old Japanese boy with a complaint of discomfort in the thigh and a small, well-defined, osteolytic lesion with cortical thinning located in the medullary space of the distal diaphysis of the femur. At 10-month follow-up, the size of the lesion had increased. Gadolinium-enhanced magnetic resonance imaging failed to detect any solid area. Curettage and bone graft were performed and confirmed a blood-filled cystic lesion. The pathological diagnosis of the cyst wall was that of nonossifying fibroma, suggesting aneurysmal bone cyst as a secondary change. An aneurysmal bone cyst is rarely found secondary to nonossifying fibroma, and the diaphyseal location is atypical for nonossifying fibroma, both of which made diagnosis challenging. Conclusion The current case is a reminder to clinicians that, although rare, nonossifying fibroma can be associated with aneurysmal bone cyst, and both can occur in the diaphysis of long bones.
Endoscopic decompression for intraforaminal and extraforaminal nerve root compression
Toshio Doi, Katsumi Harimaya, Yoshihiro Matsumoto, Osamu Tono, Kiyoshi Tarukado, Yukihide Iwamoto
Journal of Orthopaedic Surgery and Research , 2011, DOI: 10.1186/1749-799x-6-16
Abstract: The records from seventeen consecutive patients treated with endoscopic posterior decompression without fusion for intaforaminal and extraforaminal nerve root compression in the lumbar spine (7 males and 10 females, mean age: 67.9 ± 10.7 years) were retrospectively reviewed. The surgical procedures consisted of lateral or translaminal decompression with or without discectomy. The following items were investigated: 1) the preoperative clinical findings; 2) the radiologic findings including MRI and computed tomography-discography; and 3) the surgical outcome as evaluated using the Japanese Orthopaedic Association scale for lower back pain (JOA score).All patients had neurological findings compatible with a radiculopathy, such as muscle weakness and sensory disturbance. MRI demonstrated the obliteration of the normal increased signal intensity fat in the intervertebral foramen. Ten patients out of 14 who underwent computed tomography-discography exhibited disc protrusion or herniation. Selective nerve root block was effective in all patients. During surgery, 12 patients were found to have a protruded disc or herniation that compressed the nerve root. Sixteen patients reported pain relief immediately after surgery.Intraforaminal and extraforaminal nerve root compression is a rare but distinct pathological condition causing severe radiculopathy. Endoscopic decompression surgery is considered to be an appropriate and less invasive surgical option.Intraforaminal and extraforaminal nerve root compression at lumbar lesions is much rarer than intraspinal canal lesions, making the diagnosis difficult [1]. The difficulties in making a correct diagnosis could unfortunately result in a failed lumbar spine surgery.Surgical intervention is considered for patients with severe radiculopathy that does not respond to conservative treatment. As interverebral foraminal nerve entrapment mostly affects the elderly, it is better to choose a minimally-invasive surgical procedure. Consequentl
Right thoracic curvature in the normal spine
Toshio Doi, Katsumi Harimaya, Hiromichi Mitsuyasu, Yoshihiro Matsumoto, Keigo Masuda, Kazu Kobayakawa, Yukihide Iwamoto
Journal of Orthopaedic Surgery and Research , 2011, DOI: 10.1186/1749-799x-6-4
Abstract: For normal spinal measurements, 1,200 patients who underwent a posteroanterior chest radiographs were evaluated. These consisted of 400 children (ages 4-9), 400 adolescents (ages 10-19) and 400 adults (ages 20-29), with each group comprised of both genders. The exclusion criteria were obvious chest and spinal diseases. As side curvature is minimal in normal spines and the range at which curvature is measured is difficult to ascertain, first the typical curvature range in scoliosis patients was determined and then the Cobb angle in normal spines was measured using the same range as the scoliosis curve, from T5 to T12. Right thoracic curvature was given a positive value. The curve pattern was organized in each collective three groups: neutral (from -1 degree to 1 degree), right (> +1 degree), and left (< -1 degree).In child group, Cobb angle in left was 120, in neutral was 125 and in right was 155. In adolescent group, Cobb angle in left was 70, in neutral was 114 and in right was 216. In adult group, Cobb angle in left was 46, in neutral was 102 and in right was 252. The curvature pattern shifts to the right side in the adolescent group (p < 0.01) and in adult group (p < 0.001) compared to the child group. There was no significant difference in curvature pattern between adolescent and adult group.Based on standing chest radiographic measurements, a right thoracic curvature was observed in normal spines after adolescence.Coronal side curvature deformity, trunk asymmetry, and spinal body rotation are observed in patients with adolescent idiopathic scoliosis (AIS). Many studies have been conducted to elucidate the etiology of scoliosis [1,2]. In spite of these numerous investigations, it is still unclear why AIS begins in adolescence and why right thoracic scoliosis is more common than left thoracic scoliosis.Trunk asymmetry [1,3,4], right thoracic vertebral rotation [5], and right thoracic curvature have been reported in the normal spine [6,7]. Trunk asymmetry is promi
Long-term follow-up on the use of vascularized fibular graft for the treatment of congenital pseudarthrosis of the tibia
Akio Sakamoto, Tatsuya Yoshida, Yoshio Uchida, Tetsuo Kojima, Hideaki Kubota, Yukihide Iwamoto
Journal of Orthopaedic Surgery and Research , 2008, DOI: 10.1186/1749-799x-3-13
Abstract: Five girls and 3 boys with CPT were treated by vascularized fibular grafting (VFG). The average age at VFG was 7.0 years (range: 1.9–11.5 years) with an average follow-up term of 11.7 years (range: 4.9–19.6 years). Five of the children had undergone multiple operations before VFG, while the other 3 had no such history.Bone consolidation was obtained in all cases after an average term of 6.6 months (range: 4–10 months); this was with the first VFG in 7 cases but with the second VFG in 1 case. Complication of stress fracture and ankle pain occurred in 1 and 3 cases, respectively, only in cases undergoing multiple operations. Leg-length discrepancy was more prominent in the patients with multiple previous operations (mean: 7.5 cm), than in the cases with no prior surgery (mean: 0.7 cm).The long-term results of VFG for CPT were excellent, especially in the cases, with no prior surgery. VFG should be considered as a primary treatment option for CPT.Congenital pseudoarthrosis of the tibia (CPT) is one of the most difficult conditions to treat. The natural history is persistent instability and progressive deformity [1,2]. CPT is known to accompany NF1 (neurofibromatosis type 1), also called von Recklinghausen disease. Treatment options vary, including both surgical and non-surgical approaches. Surgical techniques of vascularized fibular grafting (VFG), intramedullary stabilization and external fixation have been reported to be relatively successful in the treatment of CPT [3-9].We previously reported the cases of 5 patients with CPT for whom good short-term results were obtained with the use of VFG [3]. However, long-term follow-up studies of VFG, particularly identifying limb-length discrepancy, residual angular deformity and the rates of refracture are necessary. All of those complications can compromise the functional outcome, even though pseudarthrosis may demonstrate bone consolidation [2,10]. In this study, the long-term results of VFG were evaluated for 5 previously
Dedifferentiated chondrosarcoma with leukocytosis and elevation of serum G-CSF. A case report
Akio Sakamoto, Hidetaka Yamamoto, Kazuhiro Tanaka, Shuichi Matsuda, Katsumi Harimaya, Yoshinao Oda, Masazumi Tsuneyoshi, Yukihide Iwamoto
World Journal of Surgical Oncology , 2006, DOI: 10.1186/1477-7819-4-37
Abstract: We report the case of a 72-year-old man with dedifferentiated chondrosarcoma characterized by dedifferentiated components of malignant fibrous histiocytoma- or osteosarcoma-like features in addition to conventional chondrosarcoma, arising from his pelvic bone. After hemipelvectomy, when local recurrence and metastasis were identified, leukocytosis appeared and an elevated level of serum granulocyte-colony-stimulating factor (G-CSF) was also recognized. The patient died of multiple organ failure 2 months after surgery. Autopsy specimens showed that the histological specimens of the recurrence and metastasis were dedifferentiated components, without any conventional chondrosarcoma components. G-CSF was expressed only in the dedifferentiated components, not in the chondrosarcoma components, immunohistochemically.This is the first report of chondrosarcoma, or any other primary bone tumor, with leukocytosis, probably stimulated by tumor-produced G-CSF from the dedifferentiated components.Granulocyte-colony stimulating factor (G-CSF) enhances differentiation along the neutrophil lineage, and accelerates maturation of metamyelocytes into mature neutrophils. G-CSF also prolongs the survival of neutrophils and their precursors, including stem cells[1]. Consequently, G-CSF is known to function as a hematopoietic growth factor and it is known to be responsible for leukocytosis. Normally, the serum G-CSF level is very low [2]. Production of granulocyte colony-stimulating factor (G-CSF) by tumor cells was first identified in lung carcinoma in 1977 [3]. G-CSF-producing tumors associated with leukocytosis include various types of malignancies, including lung caner [4,5], colon cancer [4], stomach cancer [4], thyroid caner [6], cervical cancer [7], malignant fibrous histiocytoma of soft tissue [8].Dedifferentiated chondrosarcoma accounts for approximately 10% of all chondrosarcomas [9]. Dedifferentiated chondrosarcoma shows both a rapid growth rate and metastatic spread, and it has
Dedifferentiated liposarcoma with leukocytosis. A case report of G-CSF-producing soft-tissue tumors, possible association with undifferentiated liposarcoma lineage
Akio Sakamoto, Hiroshi Matono, Tatsuya Yoshida, Kazuhiro Tanaka, Shuichi Matsuda, Yoshinao Oda, Yukihide Iwamoto
World Journal of Surgical Oncology , 2007, DOI: 10.1186/1477-7819-5-131
Abstract: We report the case of a 72-year-old man with dedifferentiated liposarcoma characterized by dedifferentiated components of malignant fibrous histiocytoma (MFH)-like features in addition to well-differentiated lipoma-like liposarcoma, arising from his upper arm. Preoperative laboratory data showed leukocytosis (103,700/μl). The serum level of G-CSF was also elevated (620 pg/ml [normal, <8 pg/ml]). Nine days after the surgery, the leukocytosis was relieved (WBC; 6,920/μl) and the elevated serum G-CSF level was significantly decreased (G-CSF; 12 pg/ml). One month after the surgery, leukocytosis gradually began to appear again. Three months after the surgery metastatic lung lesions were confirmed, and the patient subsequently died of respiratory problems. In the English literature regarding soft-tissue tumors with leukocytosis, including the current case, we could review a total of 6 cases of liposarcoma with leukocytosis. The subtype of these 6 liposarcoma cases was undifferentiated liposarcoma, comprising dedifferentiated liposarcoma in 4 cases and pleomorphic liposarcoma in 2 cases.Since the only other soft-tissue tumor that was associated with leukocytosis was MFH, and since MFH is characterized by the absence of any specific differentiation, we would like to propose a possible association between G-CSF-producing soft-tissue tumors and an undifferentiated liposarcoma lineage, such as dedifferentiated liposarcoma or pleomorphic liposarcoma.Granulocyte-colony-stimulating factor (G-CSF) enhances differentiation along the neutrophil lineage, and accelerates maturation of metamyelocytes into mature neutrophils. Consequently, G-CSF is known to function as a hematopoietic growth factor and it is known to be responsible for leukocytosis. G-CSF-producing tumors associated with leukocytosis include various types of malignancies. In epithelial cancers, the expression of G-CSF has been associated with poor differentiation and invasiveness [1-3]. However, it is a rare event among
Epithelioid sarcoma with muscle metastasis detected by positron emission tomography
Akio Sakamoto, Osamu Jono, Minako Hirahashi, Masafumi Oya, Yukihide Iwamoto, Ken Arai
World Journal of Surgical Oncology , 2008, DOI: 10.1186/1477-7819-6-84
Abstract: A 33-year-old man was referred to our institute with a diagnosis of Volkmann's contracture with the symptom of flexion contracture of the fingers associated with swelling in his left forearm. Magnetic resonance imaging (MRI) showed abnormal signal intensity, comprising iso-signal intensity on T1- and high-signal intensity on T2-weighted images surrounding the flexor tendons in the forearm. Diagnosis of epithelioid sarcoma was made by open biopsy, and amputation at the upper arm was then undertaken. [18F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) detected multiple lesions with an increased uptake in the right neck, the bilateral upper arms and the right thigh, as well as in the left axillary lymph nodes, with maximum standardized uptake value (SUVmax) ranging from 2.0 to 5.5 g/ml. Magnetic resonance imaging confirmed that there was a lesion within the right thigh muscle which was suggestive of metastasis, even though the lesion was occult clinically.Increased uptake on FDG-PET might be representative of epithelioid sarcoma, and for this reason FDG-PET may be useful for detecting metastasis. Muscle metastasis is not well documented in epithelioid sarcoma. Accordingly, the frequency of muscle metastasis, including occult metastasis, needs to be further analyzed.Epithelioid sarcoma was first described in 1970 [1]. Epithelioid sarcoma is an uncommon slow-growing malignant soft-tissue mass, usually found in the extremities, particularly in the hand and foot. The tumor is known to be associated with a high incidence of local recurrence and metastasis. The tumor is mostly prevalent in young adults aged between 20 and 40 years old [2]. The overall survival rates have been reported be 92.4%, 86.9% and 72.4% at 5, 10 and 15 years, respectively [3]. Epithelioid sarcoma has a diagnostic problem clinically, because its symptoms are sometimes similar to benign conditions, including inflammatory or granulomatous lesions [4].[18F]-2-fluoro-2-deoxy-D-glucose-p
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