Biomedical subjects

Nobuhiko Sugano

Publications and source records attributed to Nobuhiko Sugano.

At least 19 recordsLinked to original sources

PubMed2007

Suctioning prevents emboli during insertion of acetabular components without holes.

Embolic events can occur when inserting uncemented press-fit acetabular components (cups), especially those without holes. However, there is a paucity of literature regarding prevention of embolic events. We asked whether suctioning in the acetabulum might be as effective as suctioning during femoral insertion. We compared embolic events in 30 hips (27 patients) (Group 1) that had conventional press-fit cup fixation without holes, with 30 hips (27 patients) (Group 2) treated by suctioning from a cannula in the ilium during cup impaction. We evaluated embolic events using transesophageal echocardiography, blood gas (PaO2, PaCO2), and blood pressure preoperatively and 5 minutes after cup placement. Echocardiography showed less severe embolic events in Group 2 (23%) than in Group 1 (100%). The decrease in rate of the PaO2 and the blood pressure from baseline to 5 minutes after cup placement were lower in Group 2 than in Group 1. Our data suggest the suctioning technique is effective to reduce embolic events by cup without holes which may cause intraoperative embolic complications.

Acetabulum↗

PubMed2006

Molecular properties and intracellular localization of rat liver nuclear scaffold protein P130.

We examined the molecular basis of rat P130, a nuclear scaffold protein, and its functions. P130 comprising 845 amino acid residues possesses several functional domains and yields an electrophoretically distinctive isoform, P123, by altering its phosphorylation status in association with translocation across the nuclear membrane and from the digitonin-extractable fraction of the nucleus to the nuclear scaffold. The functional domains, NLS, NES, and zinc-finger bearing DNA-binding domains, ZF1 and ZF2, aid these translocations. P130 binds RNA through two RNA-binding domains (RB1 and RB2) similar to those of hnRNPs I and L. Microsome- and polysome-localized P130 and P123 were found in rat liver and Ac2F hepatoma cells. This localization required prior entry of P130 to the nucleus, but did not require RB1 and RB2. Thus, P130 initially purified from rat liver nuclear scaffold has the potential to play a variety of roles in biological events not only in the nuclear scaffold but also in various subcellular compartments. P130 (AB205483) is identical to matrin 3 (M63485 and BC062231), although the primary structure of rat matrin 3 has been revised, since it was first published.

Amino Acid Sequence↗

PubMed2006

Serious metallosis of a metal head due to fragmented ceramic screws in a cemented THA.

We reported a rare revision case necessitated by massive metallosis of a metal head due to a fragmented ceramic screw which had been extraarticularily used in the primary THA here and reviewed previous literature about metallosis of metal heads associated with ceramic materials. The ceramic screw had been used for the fixation of a bone graft and reattachment of the greater trochanter in the primary THA. Scanning electron microscope analysis revealed large alumina ceramic particles embedded on the bearing surface of the polyethylene. It has previously been pointed out that metallosis of an inner head occurred in bipolar case due to a fracture of the ceramic screws in contact with a proximally migrated outer head. However, this case showed that if a ceramic screw fragmented even though it was used outside of the hip joint, the fragments could migrate into bearing surface and cause serious metallosis of the metal head. Thus, we recommend that surgeons should pay special attention to the radiographic signs of ceramic failure or metallosis such as a change of the metal head contour, if an aseptic loosening or severe osteolysis is observed in a THA in which ceramic materials were used near the hip joint. And, when a surgical revision is planned, the surgeon should be prepared to exchange with a new ceramic head.

Bone Screws↗

PubMed2006

Longitudinal quantitative evaluation of lesion size change in femoral head osteonecrosis using three-dimensional magnetic resonance imaging and image registration.

It remains controversial whether some lesions of femoral head osteonecrosis regress during the natural course of the disease. With image registration, accurately matched image sets of the same subject can be acquired at different times. We applied image registration to evaluate lesion size change and assessed accuracy and usefulness compared to volume measurements and a conventional method. We also investigated whether lesions regress with this technique and with volume measurements. Baseline and 1 year minimum follow-up scans were conducted on 25 patients (31 hips) without radiological evidence of collapse. A three-dimensional (3D) spoiled gradient recalled echo sequence was used in the coronal direction (slice thickness = 2 mm; slice pitch = 1 mm). Size change was evaluated on all contiguous pairs of matched images after image registration. As a conventional method, coronal images (slice thickness = 5 mm) were reconstructed, and size change was evaluated on the five representative coronal slices. Evaluation with the conventional method identified eight lesions with apparent reduction; assessments using image registration and volume measurements identified three lesions, all within a year of initial steroid treatment and remaining at ARCO stage I at follow up. Evaluation of lesion size change using image registration was comparable to volume measurements. Inaccurate estimation of lesion size change due to mismatching of slice planes can be excluded. We demonstrated that some early lesions detected less than a year after initial steroid treatment can show size reduction with image registration as well as with volume measurements.

Adolescent↗

PubMed2006

Hydrolyses of calcium phosphates-allografts composite in physiological solutions.

Hydrolysis of calcium phosphates cement- allografts composite in calf serum and that in saline were examined in comparison with those of the calcium phosphates cement in both the solutions. The calcium phosphates cement consists of alpha-tricalcium phosphate (alpha-TCP), tetracalcium phosphate (TetCP), dicalcium phosphate dihydrate (DCPD), and hydroxyapatite (HAP), which is clinically used as Biopex. In the hydrolyses of Biopex-allografts composite in both the solutions, the calcium phosphates cement was transformed into HAP. On the other hand, in the hydrolyses of Biopex, HAP was formed after 1 day and octacalcium phosphate (OCP) was gradually formed after 7 days. In the presence of allografts, plate-like crystals were deposited and in the absence of allografts, needle-like crystals were deposited in both the solutions. By the addition of allografts, the hydrolysis process of the calcium phosphates cement was significantly changed.

Biocompatible Materials↗

PubMed2006

Comparison between hand rasping and robotic milling for stem implantation in cementless total hip arthroplasty.

We evaluated the effects of conventional hand rasping and robotic milling on the clinical and radiographic results of cementless total hip arthroplasty, with the same computed tomography (CT)-based 3-dimensional preoperative planning using a ROBODOC workstation (Integrated Surgical Systems, Davis, Calif). The robotic milling group consisted of 78 hips, and the hand-rasping group 78 hips. The radiographic findings from the preoperative planning and postoperative CT data were evaluated using the most accurate CT images reconstructed by the ROBODOC workstation. The robotic milling group showed significant superior Merle D'Aubigne hip score at 2 years. In the robotic milling group, there were no intraoperative femoral fractures, and a radiographically superior implant fit was obtained. Hand rasping had the potential to cause intraoperative femoral fractures, undersizing of the stem, unexpectedly higher vertical seating, and unexpected femoral anteversion causing inferior implant fit.

Adult↗

PubMed2006

Multidetector-CT evaluation of bone substitutes remodeling after revision hip surgery.

UNLABELLED: We evaluated remodeling of grafted bone substitutes after revision hip arthroplasty using serial examinations of multidetector-row computed tomography imaging. Ten patients (12 hips) had cementless revision surgery with grafting of beta-tricalcium phosphate granules and pastelike calcium phosphate cement in bone defects around the femoral component. At 3 weeks and 1 year postoperatively, the patients were evaluated using multidetector-row computed tomography imaging with a metal artifact minimizing protocol. New bone formation and changes in volume of beta-tricalcium phosphate and calcium phosphate cement were measured. At 1 year postoperatively, beta-tricalcium phosphate had decreased more than calcium phosphate cement. The residual volumes of calcium phosphate cement and beta-tricalcium phosphate were 78% (range, 37%-96%) and 30% (range, 10%-62%) of the initial grafted volume, respectively. The volume of the new bone that formed after absorption of beta- tricalcium phosphate was 34% (range, 11%-76%) of the initial beta-tricalcium phosphate volume. Use of cement in prior operations was an unfavorable factor in graft remodeling after revision surgery. Multidetector-row computed tomography is a promising tool for evaluating bone stock restoration of patients and influential factors of bone remodeling, and for clarifying remodeling patterns of various bone substitutes. LEVEL OF EVIDENCE: Therapeutic study, Level IV (case series). See the Guidelines for Authors for a complete description of levels of evidence.

Aged↗

PubMed2006

Does alendronate prevent collapse in osteonecrosis of the femoral head?

UNLABELLED: Progression of collapse in osteonecrosis of the femoral head is related to the repair response, especially bone resorption around the necrotic region. A preliminary clinical study was done to determine whether systemic alendronate would prevent collapse and lead to pain relief in patients with osteonecrosis of the femoral head. Fourteen patients (20 hips) with osteonecrosis of the femoral head received daily administration of 5 mg alendronate (alendronate group) for 1 year. Eight patients (13 hips) with osteonecrosis of the femoral head did not receive alendronate (control group). All patients had measurements of biochemical markers of bone turnover at entry into the study, and the patients in the alendronate group repeated the measurements at 3 months, 6 months, and 12 months. All patients had clinical and plain radiographic examinations at entry into the study and at 3 months, 6 months, and 12 months. The alendronate group showed a greater decrease of biochemical marker of bone resorption than biochemical marker of bone formation. The alendronate group showed a lower frequency of collapse of the femoral head and reported less hip pain than the control group. Our results suggest alendronate has the potential to prevent collapse of the femoral head, even with extensive necrosis, presumably by inhibiting bone resorption in the necrotic region. LEVEL OF EVIDENCE: Therapeutic study, level II (prospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Adolescent↗

PubMed2006

The custom femoral component is an effective option for congenital hip dysplasia.

Although custom-designed femoral prostheses seem more likely to be successful than off-the-shelf components for treatment of patients with osteoarthritis secondary to congenital hip dysplasia, published short-term results of custom stems with a smooth surface or titanium proximal mesh pads are no better than results for off-the-shelf components. To determine whether cementless custom femoral components with sandblasted surfaces provide better results than other custom stems, we prospectively evaluated 77 consecutive patients (99 hips) with a mean age of 54 years who had osteo-arthritis secondary to congenital hip dysplasia. The mean followup was 9 years 3 months. Forty-seven hips were classified as having Crowe Type I deformity, 41 were classified as having Crowe Type II deformity, and 11 were classified as having Crowe Type III deformity. The average Harris hip score was 97.6 points at the last followup. Radiographically, 88 hips (89%) showed bone ongrowth, seven hips (7%) showed stable fibrous fixation, and four hips (4%) showed unstable fixation. There were two intraoperative femoral fractures and varus malpositioning of four stems in the hips with stable fibrous fixation and the unstable hips. One femoral component was revised 6 years postoperatively. Although the anatomic cementless custom-designed femoral components with sandblasted surfaces provided favorable results in patients with Crowe Types I, II, and III deformities, intra-operative technical errors prevented bone ongrowth fixation.

Adult↗

PubMed2006

Spontaneous regression of steroid-related osteonecrosis of the knee.

It is unknown whether lesions of steroid-related osteonecrosis of the knee increase or decrease in size during the course of the disease after diagnosis. We sought to determine whether steroid-related osteonecrosis of the knee would have spontaneous changes in size, and if so, the factors affecting the change. We performed baseline and followup (minimum of 1 year) magnetic resonance imaging scans on 30 knees of 17 patients. We then used image registration techniques to match two sets of images. Lesion size change was evaluated on all contiguous pairs of matched magnetic resonance images. Fourteen Stage 1 (preradiographic stage) knees in seven patients showed spontaneous incomplete regression without subsequent collapse. These patients had early steroid-related lesions detected within 3 years after starting steroid treatment and all showed bilateral and multifocal involvement; lesion regression occurred regardless of location. The initial size and location of the lesions and discontinuing steroid administration did not seem to affect regression. Regression can occur in some patients with early steroid-related osteonecrosis of the knee, and the time between initiation of steroid treatment and its diagnosis might be the most significant predictive factor.

Adolescent↗

PubMed2006

Computer-assisted spherical osteotomy with a curved-bladed Tuke Saw.

Techniques for spherical osteotomy, such as rotational acetabular osteotomy, can help orthopaedic surgeons correct bony deformities and remove spherical acetabular components. Curved chisels are used during a spherical osteotomy, but they require skill and have a potential risk of damaging blood vessels or nerves. In order to perform a precise, quick and safe spherical osteotomy, we have developed a novel computer-assisted surgical tool using a vibrating bone saw, the Tuke Saw, with a curved blade that operates under the guidance of an optical navigation system. In this study, the accuracy and ease of use of this curved-bladed Tuke Saw in spherical osteotomy were examined in comparison with the conventional curved chisel. Using these surgical tools, hemispherical osteotomies were performed on rectangular parallelepiped Sawbones blocks and rotational acetabular osteotomies were performed on cadaveric pelves. The distance error with the curved-bladed Tuke Saw was significantly smaller than that with the curved chisel, and the procedure time with the Tuke Saw was approximately half that with the chisel. It can thus be concluded that the curved-bladed Tuke Saw is more accurate and easier to use than the conventional curved chisel.

Acetabulum↗

PubMed2006

Soft-tissue balance evaluation system for total hip arthroplasty by intraoperative contact pressure measurement at the hip joint.

We developed a system for measurement of contact pressure at the hip joint surfaces that enables checking of the artificial hip joint condition during surgery. First, we constructed the pressure sensor that forms the artificial joint. We installed eight small pressure sensors to the spherical head component, a part of the ball-socket joint. Next, we developed software for recording and visualizing the detected pressures that were recorded every 1 ms. The pressure distribution was displayed with the 3D computer graphics in real-time. The system enabled intuitive recognition of pressure direction 3-dimensions. Next, using the system, we conducted measurements during total hip arthroplasty. Although it requires some improvements in its measurement accuracy, the system allows real-time acquisition of information on the artificial hip joint in real-time. Further improvements of the calibration method should enable more accurate measurements. As a complete system, it will be a useful tool for selecting an appropriate implant that fits a patient's hip joint or for estimating the risk of complications after surgery.

Arthroplasty, Replacement, Hip↗

PubMed2005

Application of 3D-MR image registration to monitor diseases around the knee joint.

PURPOSE: To estimate the accuracy and consistency of a method using a voxel-based MR image registration algorithm for precise monitoring of knee joint diseases. MATERIALS AND METHODS: Rigid body transformation was calculated using a normalized cross-correlation (NCC) algorithm involving simple manual segmentation of the bone region based on its anatomical features. The accuracy of registration was evaluated using four phantoms, followed by a consistency test using MR data from the 11 patients with knee joint disease. RESULTS: The registration accuracy in the phantom experiment was 0.49+/-0.19 mm (SD) for the femur and 0.56+/-0.21 mm (SD) for the tibia. The consistency value in the experiment using clinical data was 0.69+/-0.25 mm (SD) for the femur and 0.77+/-0.37 mm (SD) for the tibia. These values were all smaller than a voxel (1.25 x 1.25 x 1.5 mm). CONCLUSION: The present method based on an NCC algorithm can be used to register serial MR images of the knee joint with error on the order of a sub-voxel. This method would be useful for precisely assessing therapeutic response and monitoring knee joint diseases; normalized cross-correlation; accuracy.

Algorithms↗

PubMed2005

Gait analysis system for assessment of dynamic loading axis of the knee.

The purpose of this study was (1) to demonstrate a computer-assisted gait analysis system that can visualize the locus of the dynamic loading axis on the proximal tibia joint surface, and (2) to assess the accuracy of this system in a patient with bilateral knee osteoarthritis (OA). This system uses force plate data, CT skeletal structure data and motion capture data obtained from an infrared position sensor. The relative positions between bones and markers were used to calculate skeletal model movement based on movement of the markers. The locus of the dynamic loading axis on the knee joint was defined as the point on the proximal tibia joint surface that intersected with the loading axis of the lower limb, which passed through the centre of the femoral head and the centroid of multiple points surrounded by the distal tibia joint surface contour. To assess the accuracy of this system, open MRI was used to evaluate positions of skin markers against bones in six healthy volunteers. The locus in a patient was affected by differences between the varus knee with medial compartment OA on the non-operative side and the knee treated with high tibial osteotomy (HTO) on the opposite side. At knee flexion angles of 0 degrees, 15 degrees and 30 degrees, the mean value of measurement error for point locations on the locus was within 5.6% of joint width in the lateral direction (JWLD) on the proximal tibia joint. This system can provide clinically useful information for evaluation of the dynamic loading axis on the knee joint surface.

Aged↗

PubMed2005

Change in the locus of dynamic loading axis on the knee joint after high tibial osteotomy.

The purpose of this study was to visualise the locus of the dynamic loading axis on the knee joint, and to evaluate changes in this locus during gait after high tibial osteotomy (HTO) in three patients who underwent HTO for medial compartment osteoarthritis (OA) of a varus knee. The bone structure of the lower limb and the relative position of skin markers were acquired from CT images. Motion capture data was acquired using spherical skin markers. Skeletal model movement during gait was calculated based on the movement of the markers. The locus of the dynamic loading axis on the knee joint was defined as the point on the proximal tibia joint surface that intersected with the loading axis of the lower limb, which passed through the centre of the femoral head and the centroid of multiple points surrounded by the distal tibia joint surface contour. This system was able to visualise the locus of the dynamic loading axis on the knee joint and not only lateral but also anterior-posterior direction movement. After HTO, the locus shifted from a medial and posterior area of the medial joint edge of the knee to a central area of the knee joint surface. This indicates that HTO shifted the dynamic loading axis. Lateral movement of the dynamic loading axis in the early stance phase of gait was reduced within a year after HTO.

Aged↗

PubMed2005

Application of three-dimensional magnetic resonance image registration for monitoring hip joint diseases.

The purpose of this study was to estimate the accuracy of a method in which three-dimensional (3D) magnetic resonance (MR) volume registration is used for monitoring hip joint disease. Data were analyzed using a normalized cross-correlation (NCC) algorithm involving a user-selected 3D box including the proximal femur. Most of the femoral head was not included in the 3D box because it can become deformed during the course of disease. The accuracy of registration around the femoral head was evaluated using five phantoms and clinical MR data of 17 patients with hip joint disease. In the phantom experiment, registration accuracy was evaluated using four fiducial markers attached to the femoral head. In the experiment using clinical data, registration accuracy was evaluated using a landmark in the femoral head. The registration accuracy in the phantom and clinical experiment was 0.43+/-0.18 mm (S.D.) and 1.12+/-0.46 mm (S.D.), respectively. The former is a value less than half the minimum dimension of a voxel (1.25 x 1.25 x 1.0 mm). Although the latter is slightly larger than the minimum dimension of a voxel, actual errors would be smaller because of the uncertainty in landmark localization. In conclusion, the present method based on an NCC algorithm can be used to accurately register serial MR images of the femoral heads with an error on the order of a voxel. We believe that this method is sufficiently accurate for monitoring hip joint diseases.

Algorithms↗

PubMed2005

Fat-suppressed 3D spoiled gradient-echo MRI and MDCT arthrography of articular cartilage in patients with hip dysplasia.

OBJECTIVE: Our objective was to assess the diagnostic ability of MDCT arthrography for acetabular and femoral cartilage lesions in patients with hip dysplasia. MATERIALS AND METHODS: A disorder of the articular cartilage was evaluated in 20 hips of 18 patients with acetabular dysplasia who did not have osteoarthritis or who had early stage osteoarthritis before undergoing pelvic osteotomy surgery. The findings on fat-suppressed 3D fast spoiled gradient-echo MRI and MDCT arthrography of the hip were evaluated by two independent observers, and sensitivity, specificity, and accuracy were determined using arthroscopic findings as the standard of reference. Kappa values were calculated to quantify the level of interobserver agreement. RESULTS: The sensitivity and specificity for the detection of any cartilage disorder (grade 1 or higher) were (observer 1/observer 2) 49%/67% and 89%/76%, respectively, on MRI, and 67%/67% and 89%/82%, respectively, on CT arthrography. The sensitivity and specificity for the detection of cartilage lesions with substance loss (grade 2 or higher) were (observer 1/observer 2) 47%/53% and 92%/87%, respectively, on MRI, and 70%/79% and 93%/94%, respectively, on CT arthrography. CT arthrography provided significantly higher sensitivity in the detection of grade 2 or higher lesions than MRI for both observers. Interobserver agreement in the detection of grade 2 or higher cartilage lesions was moderate (kappa = 0.53) on MRI and substantial (kappa = 0.78) on CT. CONCLUSION: MDCT arthrography is a sensitive and reproducible method for assessing articular cartilage lesions with substance loss in patients with hip dysplasia.

Adolescent↗

PubMed2005

Estimation of dislocation after total hip arthroplasty by 4-dimensional.

We constructed a 4-dimensional musculoskeletal model for patients who have undergone total hip arthroplasty (THA), which aimed to simulate the movement of the patient's inner body structure and estimate the complications that can arise with THA. The model reflects patient-specific characteristics of the bone geometry, implant alignment and hip movement. In order to estimate the direction of the muscle force and the length of the muscles, we developed a string-type muscle model that represents the route of the muscles. The strings expand and contract according to the movement of the origin and insertion location of the muscle. We developed models for the seven muscles related to movement of the hip joint. By using this model, clinicians will be able to predict the possibility of dislocation or recognize the actual causes of dislocation, as well as any possible influences the muscle may have on dislocation.

Arthroplasty, Replacement, Hip↗