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Mitsuo Ochi

Publications and source records attributed to Mitsuo Ochi.

At least 19 recordsLinked to original sources
PubMed2006

Conservative surgery for well-differentiated liposarcomas of the extremities adjacent to major neurovascular structures.

BACKGROUND: There is no clear consensus as to the appropriate nomenclature and the best surgical strategy for well-differentiated liposarcomas. A wide surgical excision is recommended over marginal resection for local control of well-differentiated liposarcomas. However, this surgical procedure should be reconsidered for lesions, which come into contact with major neurovascular structures. METHODS: Between 1998 and 2004, 12 well-differentiated liposarcomas of the extremities were treated at our institute. Among them, nine lesions (75%) adjacent to major nerves or blood vessels were marginally resected with careful dissection of these critical structures. The clinical outcomes were reviewed for a mean follow-up time of 4 years. RESULTS: Seven patients continued to be disease-free without any loss of limb function. One patient developed a local recurrence 30 months postoperatively. The other patient with a foot lesion involving the fourth metatarsal bone has experienced slight difficulty in gait-balancing due to the fourth toe amputation, but remains free of disease. The local control rate was 88.9%, even though seven lesions were resected with positive surgical margins. CONCLUSIONS: Our findings suggested that well-differentiated liposarcomas frequently arise in close proximity to major nerves or blood vessels. Marginal resection alone seems to be adequate for these lesions to preserve critical structures.

Adult↗
PubMed2006

Postoperative segmental C5 palsy after cervical laminoplasty may occur without intraoperative nerve injury: a prospective study with transcranial electric motor-evoked potentials.

STUDY DESIGN: Intraoperative neurophysiologic monitoring with transcranial electric motor-evoked potentials was performed on patients who underwent cervical laminoplasty at a university hospital in a prospective study. OBJECTIVE: To evaluate the usefulness of intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials for prediction of the occurrence of segmental motor paralysis after cervical laminoplasty. SUMMARY OF BACKGROUND DATA: Segmental motor paralysis occasionally occurs among patients who undergo expansive laminoplasty for cervical myelopathy, and it has been attributed to nerve root lesions caused by either a traumatic surgical technique or a tethering effect after decompression. METHODS: Sixty-two consecutive patients (47 men and 15 women; mean age 64 years [range 32-89]) who were scheduled to undergo cervical laminoplasty under intraoperative spinal cord monitoring with transcranial electric motor-evoked potentials were included in this study. Transcranial electrical stimulations were delivered through pin-type electrodes, and the evoked potentials were recorded over the deltoid, biceps, and triceps muscles in the bilateral upper extremities and thoracic spinal cord. RESULTS: Intraoperative evoked potentials were successfully recorded in all muscles in 57 patients (92%), and incomplete evoked potentials were recorded in the remaining 5 patients. No critical decrease in the amplitude of the evoked potentials was observed in any of the 62 patients. All patients showed sufficient postoperative recovery from their clinical symptoms; however, postoperative transient C5 palsy occurred in 3 patients. CONCLUSIONS: No abnormalities were observed on transcranial electric motor-evoked potential monitoring, even in those patients who developed postoperative transient C5 palsy. These results suggest that the development of postoperative C5 palsy after cervical laminoplasty is not associated with intraoperative injury of the nerve root or the spinal cord, although the precise mechanism of its development is still unclear. Surgeons should be aware that C5 palsy is a possible complication of cervical laminoplasty, even in the absence of intraoperative nerve injury.

Adult↗
PubMed2006

A prospective study of 3-day versus 2-week immobilization period after anterior cruciate ligament reconstruction.

BACKGROUND: Aggressive early rehabilitation is recommended after reconstruction of the anterior cruciate ligament (ACL) using a patellar tendon-bone graft. However, rehabilitation after reconstruction of ACL using the multistranded hamstring is controversial. In this study, we compared the clinical results of 3-day immobilization after reconstruction of ACL using the multistranded hamstring, with those of 2-week immobilization prospectively. METHODS: A total of 30 consecutive patients with ruptured ACL underwent single-socket ACL reconstruction. 10 male and 5 female patients (mean age of 29.2+/-10.0 years) were prospectively randomized for a 3-day immobilization period, and 6 male and 9 female patients (mean age of 27.3+/-10.9 years) were randomized for a 2-week immobilization period. We measured the anterior laxity with a KT-2000 arthrometer, joint position sense, and thigh muscle strength at 3, 6 and 12 months after surgery. RESULTS AND CONCLUSIONS: There were no statistically significant differences between the two groups. We concluded that the post-operative 3-day immobilization period is preferable to the longer 2-week period in our rehabilitation program from the viewpoint of psychological load to the patients and the duration of hospitalization after ACL reconstruction using multistranded hamstring tendons.

Adolescent↗
PubMed2006

Surgical outcome of posterior decompression for cervical spondylosis with unilateral upper extremity amyotrophy.

STUDY DESIGN: Case studies of patients with cervical spondylosis with unilateral upper extremity amyotrophy. OBJECTIVE: To clarify the surgical outcome of posterior decompression for this amyotrophy. SUMMARY OF BACKGROUND DATA: Cervical spondylosis sometimes causes a characteristic severe muscular atrophy without sensory disturbance or lower-extremity dysfunction, which is the so-called "cervical spondylotic amyotrophy." However, response to treatment, especially to posterior decompression, has not been well understood. METHOD: This study included 32 patients. All underwent posterior cervical laminoplasty, and 22 patients had an additional foraminotomy. Preoperative and postoperative muscle power and results of imaging and electrophysiologic studies were evaluated. The follow-up period averaged 78 months. Whether impingement was against the ventral nerve root (VNR) or anterior horn (AH) in the spinal cord was assessed according to these findings. These cases were divided into proximal type and distal type according to the most severely atrophic muscle and compared statistically. RESULTS: Severe preoperative muscle atrophy was observed in the deltoid and biceps muscles of 24 patients (proximal type) and in the forearm and hand muscles of 8 patients (distal type). Impingements against the VNR and AH were observed in 21 and 28 cases, respectively, and 17 cases had impingement of both the VNR and AH. Improvements in muscle atrophy after surgery were observed in 25 cases. In proximal-type patients, muscle power improved in 92% of cases but was improved in only 38% of the distal-type cases. CONCLUSIONS: Laminoplasty and foraminotomy were effective in the treatment of most patients with this syndrome, although the outcome in the distal type was inferior to that in the proximal type.

Adult↗
PubMed2006

Relationship between the shape of tibial spurs on X-ray and meniscal changes on MRI in early osteoarthritis of the knee.

OBJECTIVE: The purpose of this study was to evaluate the relationship between the shape of tibial spurs on plain X-rays and the meniscal changes on magnetic resonance imaging (MRI) in early osteoarthritis of the knee. MATERIALS AND METHODS: Sixty-three patients (age range, 40 to 59 years; average, 51.8) underwent X-ray and MRI examinations of their knees. Ligament injuries caused by trauma and Kellgren Radiographic Grades III and IV on X-ray were excluded. The shapes of the medial and lateral tibial spurs on X-ray were classified into four types: (a) normal type; (b) horizontal type, in which the spur protruded horizontally; (c) upward type, in which the spur protruded upward; and (d) downward type, in which the spur protruded downward. The femorotibial angle (FTA) on the X-rays was also measured. The medial and lateral meniscal displacement rates on MRI were measured by the proportion by which the meniscal lesion protruded from the edge of the tibial joint surface to the overall meniscal width. The medial and lateral meniscal signal changes on MRI were classified into three types: (a) normal type; (b) intrameniscal type, which showed a high signal within the meniscus; and (c) tear type, which showed a high signal extending to the tibial joint surface. The relationships between the shape of the medial and lateral tibial spur classification on X-ray, the medial and lateral meniscal displacement rates on MRI, the medial and lateral meniscal signal changes on MRI and the FTA were evaluated statistically. RESULTS: Statistically significant correlations were observed between the medial tibial spur classification on X-ray, the medial meniscal displacement rate on MRI and the medial meniscal signal change classification on MRI. In the downward type of medial tibial spur, the medial meniscal displacement rate (50.46+/-17.95%) and the percentage (8 out of 8 cases; 100%) involving the tear type of medial meniscus were greater than the other types. Statistical significance was not observed among the lateral tibial spur classification on X-ray, the lateral meniscal displacement rate on MRI and the lateral meniscal signal change classification on MRI. However, in the horizontal type of lateral tibial spur, the percentage (7 out of 10 cases; 70%) involving the tear type of lateral meniscus was greater than the other types. Correlations tended to be observed between the medial meniscal displacement rate on MRI and the FTA. CONCLUSIONS: In this study, there was a relationship between the shape of the tibial spur on X-ray and the meniscal changes on MRI in early osteoarthritis of the knee. The shape of the medial tibial spur on X-ray can be a useful indicator for predicting the progression of osteoarthritis of the knee. A downward type of medial tibial spur classification on X-ray may be a risk factor for developing severe osteoarthritis of the knee.

Adult↗
PubMed2006

Magnetic targeting of bone marrow stromal cells into spinal cord: through cerebrospinal fluid.

We established a new magnetic targeting system in which bone marrow stromal cells migrate through the cerebrospinal fluid to the desired site in the spinal cord in rats. Subarachnoid injection has been reported as a minimally invasive method of transplantation of bone marrow stromal cells for spinal cord injury. It may be, however, less effective than direct injection into the spinal cord in terms of cell delivery. After implantation of a magnet, subarachnoid injection of bone marrow stromal cells labeled with magnetic beads was performed. Greater numbers of bone marrow stromal cells aggregated on the surface of the spinal cord owing to the magnetic force. This targeting system may be a useful tool in minimally invasive transplantation of bone marrow stromal cells for the treatment of spinal cord injury.

Animals↗
PubMed2006

Augmentation of tendon attachment to porous ceramics by bone marrow stromal cells in a rabbit model.

Tendon attachment to interconnected porous calcium hydroxyapatite ceramics (IP-CHA) with cultured bone marrow stromal cells (BMSC) was analysed. The purpose of this study was to evaluate whether BMSC in IP-CHA could augment the tendon attachment to IP-CHA histologically and biomechanically. Eighteen Japanese white rabbits were used. Cultured BMSCs were subcultured in IP-CHA. The grafted tendon and IP-CHA with BMSC complex were implanted in a bone defect of the knee [BMSC(+) group]. In the contralateral knee, a tendon and IP-CHA without BMSC complex were implanted [BMSC(-) group]. Histological findings of the interface between the tendon and IP-CHA were similar in the two groups 3 weeks after the operation. However, 6 weeks after the operation, more abundant bone formation around the tendon was observed in the BMSC(+) group. The direct apposition of the tendon to bone in pores and collagen fibre continuity between the tendon and fibrous tissue in pores were observed. In biomechanical evaluation, the maximum pull-out load of the tendon from the IP-CHA in the BMSC(+) group was significantly higher than that in the BMSC(-) group 6 weeks after the operation. BMSCs cultured in IP-CHA could augment tendon attachment to IP-CHA.

Animals↗
PubMed2006

Painful os intermetatarseum in athletes: report of four cases and review of the literature.

INTRODUCTION: A painful os intermetatarseum, which described the compression of the deep peroneal nerve by an os intermetatarseum, is a very rare condition. The authors reported four cases of painful os intermetatarseum in athletes and reviewed the present literature. CASE PRESENTATION: We present four cases of a painful os intermetatarseum in athletes, who complained of pain over the dorsum of their foot associated with paresthesias in the first web space. Surgical excision of the os intermetatarseum relieved the pain in all patients. All patients returned to previous sporting activities. CONCLUSION: We should consider a painful os intermetatarseum as being the cause of dorsal foot pain in athletes, and surgical excision of the os intermetatarseum is effective for these patients.

Adolescent↗
PubMed2006

Temporal change of joint position sense after posterior cruciate ligament reconstruction using multi-stranded hamstring tendons.

A total of 29 patients who had undergone posterior cruciate ligament (PCL) reconstruction using multi-stranded hamstring tendons were prospectively followed-up for joint stability and proprioceptive function at a minimum of 24 months after surgery. We measured temporal changes of the posterior laxity by stress radiography and the KT-2000 arthrometer, and we also measured joint position sense for an average of 42 months (range 24-78 months). In terms of results, improvement of joint stability was observed postoperatively and maintained over 2 years after PCL reconstruction, although posterior stability in the reconstructed knee was not identical to the contralateral normal knee. Although joint position sense worsened just after reconstruction, it gradually recovered from 18 months after surgery. However, proprioceptive function after PCL reconstruction did not recover to the same level as in the contralateral normal knee even over 24 months after surgery.

Adolescent↗
PubMed2006

Natural history of bone bruises after acute knee injury: clinical outcome and histopathological findings.

The purpose of this paper is to review the scientific literature on the natural history of bone bruises and the experimental studies regarding the histopathological effects of impaction load on articular cartilage and subchondral bone. Bone bruises with subchondral or osteochondral injuries, or geographic bone bruises seemed to be persistent for years after trauma on MRI. Biopsy samples of the articular cartilage overlying the bone bruise lesions showed degeneration or necrosis of chondrocytes and loss of proteoglycan. Experimental studies using a single impact load revealed chondrocytes death, alteration of the mechanical properties of cartilage explants and/or an increase in the thickness of subchondral bone. These data are indicative of a significant injury to normal articular cartilage homeostasis, and support the suggestion that severe bone bruise is a precursor of early degenerative changes. We recommend delaying return to full weightbearing status when a severe bone bruise is detected to prevent further collapse of subchondral bone and further aggravation of articular cartilage injury.

Acute Disease↗
PubMed2006

Mobilization of bone marrow-derived mesenchymal stem cells into the injured tissues after intraarticular injection and their contribution to tissue regeneration.

The purpose of present study was to evaluate active mobilization effect of mesenchymal stem cells (MSCs) into injured tissues after intraarticular injection of MSCs, and to evaluate their contribution to tissue regeneration. MSCs, which were obtained from green fluorescent protein (GFP) transgenic Sprague-Dawley (SD) rat and cultivated, were injected into normal SD rats in which multiple tissues had been injured including anterior cruciate ligament (ACL), medial meniscus, and articular cartilage of the femoral condyles. At 4 weeks after injection of MSCs, fluorescent microscopic observation, immunohistochemical or histological examinations were performed to evaluate mobilization of MSCs into injured tissue and their contribution to tissue regeneration. In the group of 1 x 10(6) MSCs injection, GFP positive cells could mobilize into the injured ACL alone in all 8 knees. In the group of 1 x 10(7) MSCs injection, GFP positive cells were observed in the injured site of ACL in all 8 knees and in the injured site of medial meniscus and cartilage of femoral condyles in 6 of 8 knees. More interestingly, extracellular matrix stained by toluidine blue was present around GFP positive cells in the injured femoral condyles cartilage and medial meniscus, indicating tissue regeneration. Intraarticularly injected MSCs could mobilize into the injured tissues, and probably contributed to tissue regeneration. This study demonstrated the possibility of intraarticular injection of MSCs for the treatment of intraarticular tissue injuries including ACL, meniscus, or cartilage. If this treatment option is established, it can be minimally invasive compared to conventional surgeries for these tissues.

Animals↗
PubMed2006

Effects of CD44 antibody-- or RGDS peptide--immobilized magnetic beads on cell proliferation and chondrogenesis of mesenchymal stem cells.

We evaluated the efficacy of a novel mesenchymal stem cell (MSC) delivery system using an external magnetic field for cartilage repair in vitro. MSCs were isolated from the bone marrow of Sprague Drawley rats and expanded in a monolayer. To use the MSC delivery system, two types of MSC-magnetic bead complexes were designed and compared. Expanded MSCs were combined with small-sized (diameter: 310 nm) carboxyl group-combined (0.01-0.04 micromol/mg) magnetic beads, Ferri Sphere 100C, through either anti-rat CD44 mouse monoclonal antibodies or a synthetic cell adhesion factor, arginine (R)-glycine (G)-aspartic acid (D)-serine (S) (RGDS) peptide. Both cell complexes were successfully created, and were able to proliferate in monolayer culture up to at least day 7 after separation of magnetic beads from the cell surface, although the proliferation of the complexes was slower in the early period of culture than that of non-labeled rat MSCs (after 7 days of culture: proliferation of CD44 antibody-bead complexes, approximately 50%; RGDS peptide-bead complexes, 70% versus non-labeled rat MSCs, respectively). These complexes were seeded onto culture plates with or without an external magnetic force (magnetic flux density was 0.20 Tesla at a distance of 2 mm from plate base) generated by a neodymium magnet, and supplemented with chondrogenic differentiation medium. Both complexes could be attached and gathered effectively under the influence of the external magnet, and CD44-bead complexes could effectively generate chondrogenic matrix in monolayer culture. In a three-dimensional culture system, the production of a dense chondrogenic matrix and the expression of type II collagen and aggrecan mRNA were detected in both complexes, and the chondrogenic potential of these complexes was only a little less than that of rat MSCs alone. Thus, we conclude that due to the fact that MSC-RGDS peptide-bead complexes are composed using a biodegradable material, RGDS peptide, as a mediator, the RGDS peptide-bead complex is more useful for minimally invasive clinical applications using our design of magnetic MSC delivery system than CD44 antibody-beads.

Animals↗
PubMed2006

The long-term results of meniscus transplantation for articular cartilage defects in the knee joint.

The purpose of this study was to examine the long-term clinical results of meniscus transplantation for articular cartilage defects in the knee joint. The type of study was case series. From October 1990 to June 1995, eight cases underwent allogenic or autogenic meniscus transplantations for articular cartilage defects, and seven cases were available for follow-up evaluations. The age at surgery ranged from 14 to 42 years of age (average 22.5). In one case, transplantation of tissue-engineered cartilage was performed due to pain 5 years after surgery. The other six cases were followed up for 8-13 years (average 10.1). The size of the cartilage defect ranged from 1.0 to 6.3 cm2 (average 2.8 cm2). Patients were evaluated with the Lysholm score and MR images. We also performed arthroscopic examinations in three cases at the final evaluation. This study leads to the conclusion that meniscus transplantation for articular cartilage damage is not comparable to autologous chondrocyte transplantation. Two cases showed a good clinical outcome but the tissue remained as fibrocartilage tissue in the long-term.

Adolescent↗
PubMed2006

Retrograde drilling for osteochondral lesions of the talar dome.

BACKGROUND: For the treatment of osteochondral lesions of the talar dome without detachment of the cartilage, there is little information on whether transmalleolar drilling or retrograde drilling is more effective in terms of clinical and morphologic evaluations. HYPOTHESIS: Retrograde drilling may be more effective than transmalleolar drilling for lesions without cartilage detachment. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: Subjects were 30 patients with lesions on 1 foot of grade 0 or I, determined according to a modified Pritsch classification system. Nineteen patients underwent transmalleolar drilling (TMD group), and 11 patients underwent retrograde drilling (RD group). Ankle arthroscopy was performed 1 year postoperatively to evaluate cartilage conditions. RESULTS: Arthroscopic findings revealed that in the TMD group, 11 lesions (57.9%) were unchanged (grade I), and 8 lesions (42.1%) had deteriorated from grade 0 to I; in the RD group, 3 lesions (27.2%) had improved from grade I to 0, and 8 (72.8%) were unchanged (2 grade 0 lesions and 6 grade I lesions). There was a significant difference between the 2 groups in the distribution of cases that had improved, were unchanged, or had deteriorated (P < .0001). CONCLUSIONS: This study showed that compared with transmalleolar drilling, retrograde drilling for osteochondral lesions of the talar dome can improve the arthroscopic assessment of the lesions.

Adolescent↗
PubMed2006

Knee joint position sense in compressive myelopathy.

STUDY DESIGN: The knee joint position sense (JPS) and kinesthesia were measured in patients with compressive myelopathy. OBJECTIVES: To find out how the knee JPS and kinesthesia are useful to evaluate lower limb function in patients with compressive myelopathy. SUMMARY OF BACKGROUND DATA: No previous reports have been written on the quantitative analysis of knee joint proprioception in myelopathy patients. METHODS: Twenty-one compressive myelopathy patients with a mean age of 64 years were studied. The measured values of JPS and kinesthesia were examined in relation to the following: lower limb function and central motor conduction time (CMCT). RESULTS: Inaccurate angles of the knee JPS in patients with severe walking disability were significantly larger than those in patients with mild disability. Inaccurate angles of the knee JPS in patients with severe sensory disturbance were significantly larger than those in patients with mild disturbance. CMCT showed a significant correlation to the knee JPS. CONCLUSIONS: The knee JPS was useful to evaluate lower limb function in patients with compressive myelopathy.

Adult↗
PubMed2006

Corticospinal tract conduction block results in the prolongation of central motor conduction time in compressive cervical myelopathy.

OBJECTIVE: The objective of this study was to analyze corticospinal function in patients with compressive cervical myelopathy and to elucidate the mechanism underlying its prolonged central motor conduction time (CMCT). METHODS: Motor evoked potentials following transcranial magnetic stimulation (TMS) and peripheral conduction time in the ulnar and tibial nerves following electrical stimulation were measured from the abductor digiti minimi (ADM) and abductor hallucis (AH) muscles in 24 patients with compressive cervical myelopathy and used to calculate CMCT. Spinal cord evoked potentials (SCEPs) following transcranial electric stimulation were recorded intraoperatively from the C2-3 to C6-7 intervertebral levels. Correlations between prolonged CMCT and SCEP values were then estimated. RESULTS: The shorter/longer CMCT between the patients' right and left ADM and AH were 8.5+/-2.9/11.5+/-3.3 and 16.2+/-3.1/18.4+/-3.3 ms, respectively (mean+/-SD). The SCEPs amplitude at C6-7, compared to C2-3, was 25.7+/-21.0%. The attenuation of SCEP amplitude, but not latency, at C6-7 correlated significantly with CMCT prolongation. CONCLUSIONS: Our data support the view that CMCT prolongation is primarily due to corticospinal conduction block, rather than conduction delay. SIGNIFICANCE: Insight was provided into the mechanism of corticospinal dysfunction in compressive cervical myelopathy.

Action Potentials↗
PubMed2006

Effects of interconnecting porous structure of hydroxyapatite ceramics on interface between grafted tendon and ceramics.

The purpose of this study was to evaluate histologically and biomechanically the interface between porous hydroxyapatite ceramics and a tendon grafted into ceramics, and to compare the interface in two ceramics with different porous structures: interconnected porous calcium hydroxyapatite ceramics (IP-CHA) with an effective porosity index (interpore diameter > 20 microm) of 63.6%, and porous calcium hydroxyapatite ceramics with less interconnection (HA-L) with an effective porosity index of 5.5%. The tendon-IP-CHA complex and the tendon-HA-L complex were implanted into the bone defects made in both knees of rabbits. With IP-CHA, abundant fibrous tissue, including vessels and collagen fiber continuity, was observed inside interface-region pores. The amount of osseous tissue in interface-region pores increased over time, and at 24 weeks after operation, the tendon was in direct contact with the osseous tissue in IP-CHA. With HA-L, the amount of fibrous tissue in interface-region pores was low and did not increase. The results of biomechanical analysis revealed that the maximum tendon pull-out load from IP-CHA was significantly higher than that from HA-L. With the porous hydroxyapatite ceramics having highly interconnecting porous structure, a bioactive interface was achieved between ceramics and grafted tendon. On the basis of these results, we conclude that bone defects, including tendon insertion, can be reconstructed using IP-CHA.

Animals↗