Publications by authors named "Kei Matsuki"

13 Publications

  • Page 1 of 1

In vivo measurement of distance between scapular neck and polyethylene insert during active external rotation in shoulders with Grammont type reverse prosthesis.

Clin Biomech (Bristol, Avon) 2021 Apr 26;84:105341. Epub 2021 Mar 26.

Department of Mechanical & Aerospace Engineering, University of Florida, 330 MAE-A P.O. Box 116250, Gainesville, FL 32611-6250, USA.

Background: Scapular notching is a frequently observed complication after reverse shoulder arthroplasty. Impingement of the humeral plastic insert against the scapular neck is believed to be the cause of notching. There have been no in vivo studies that analyzed the positional relationship between the scapular neck and humeral insert. The purpose of this study was to measure the distance between the scapular neck and insert in shoulders with Grammont-type prostheses during active external rotation at the side.

Methods: Eighteen shoulders with Grammont-type prostheses were enrolled in this study. There were 13 males and 5 females, and the mean age at surgery was 74 years (range, 63-91). Fluoroscopic images were recorded during active external rotation at the side from maximum internal to external rotation at an average of 14 months (range, 7-24) after surgery. Implant kinematics were determined with three-dimensional models of the implants and fluoroscopic images using model-image registration techniques. Based on the implant kinematics, the closest distance between the scapular neck and insert was computed at each 5° increment of glenohumeral internal/external rotation.

Results: Mean glenohumeral abduction during rotation was 17°-22°. The mean distance between the neck and insert was approximately 1 mm throughout the activity. The separation distance tended to narrow with arm external rotation, but the change was not significant.

Interpretation: The small distance between the scapular neck and insert in early post-operative reverse shoulder arthroplasty patients may be associated with the high incidence of scapular notching in Grammont-type prostheses.
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http://dx.doi.org/10.1016/j.clinbiomech.2021.105341DOI Listing
April 2021

Procedure-Related Complications and Survival after Gastrostomy: Results from a Japanese Cohort.

Ann Nutr Metab 2020 24;76(6):413-421. Epub 2021 Feb 24.

Department of Gastroenterology and Hepatology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.

Introduction: In 2010, a large-scale multi-institutional study in Japan showed a good prognosis for percutaneous endoscopic gastrostomy (PEG). However, the function and efficacy of PEG are not fully understood by patients, families, and health-care professionals; thus, the number of PEG treatments in Japan has declined. Therefore, we aimed to investigate the safety of the PEG procedure and subsequent survival after PEG.

Methods: In total, 249 PEGs were performed at Juzenkai Hospital from 2005 to 2017. PEG was originally performed using the pull method and then by a modified introducer method from mid-2011. We examined procedure-related complications and survival rates after PEG.

Results: Fifty-one (20.5%) procedure-related complications occurred; emergency surgery was required in 4 cases. Infections accounted for 76.5% (39/51) of complications. More infections occurred with the pull method than with the modified introducer method. The 1-year survival rate was 66.8%; the median survival time was 678 days. Nine patients (3.6%) died within 30 days; no deaths were directly related to PEG. Sex, age, and albumin level before surgery significantly influenced the prognosis.

Conclusion: Due to changes in the PEG insertion method and other factors, PEG has become a safer treatment method. Additionally, PEG-based nutritional supplementation is associated with adequate survival.
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http://dx.doi.org/10.1159/000513616DOI Listing
February 2021

Accuracy of High-Throughput Nanofluidic PCR-Based Pneumococcal Serotyping and Quantification Assays Using Sputum Samples for Diagnosing Vaccine Serotype Pneumococcal Pneumonia: Analyses by Composite Diagnostic Standards and Bayesian Latent Class Models.

J Clin Microbiol 2018 05 25;56(5). Epub 2018 Apr 25.

Department of Clinical Medicine, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan

The lack of reliable diagnostic tests for detecting vaccine serotype pneumococcal pneumonia (VTPP) remains a challenging issue in pneumococcal vaccine studies. This study assessed the performances of high-throughput nanofluidic PCR-based pneumococcal serotyping and quantification assay methods using sputum samples (the nanofluidic sputum quantitative PCR [Sp-qPCR] assay) to diagnose 13-valent pneumococcal conjugate VTPP compared with the performance of the serotype-specific urinary antigen detection (UAD) assay using urine samples. Adult pneumonia patients from Japan were enrolled in this study between September 2012 and August 2014. Sputum samples were subjected to the nanofluidic Sp-qPCR assay, quantitatively cultured, and serotyped by the Quellung reaction (SpQt). Urine samples were tested by the UAD method. The diagnostic performances of these tests were assessed using composite reference standards and Bayesian latent class models (BLCMs). Among 244 total patients, 27 (11.1%) tested positive with the UAD assay, while 16 (6.6%) and 34 (13.9%) tested positive with the SpQt and nanofluidic Sp-qPCR assays, respectively, with a cutoff value of ≥10 DNA copies/ml, which showed the maximum value of the Youden index. Using BLCMs, the estimated prevalence for VTPP was 12.9%, and the nanofluidic Sp-qPCR assay demonstrated the best performance (sensitivity, 90.2%; specificity, 96.9%), followed by UAD (sensitivity, 75.6%; specificity, 97.9%) and SpQt (sensitivity, 45.8%; specificity, 99.5%). However, when a higher cutoff value of ≥10 DNA copies/ml was applied, the performance of UAD became comparable to that of Sp-qPCR. The vaccine serotype-specific pneumococcal DNA load in sputum among UAD-positive patients was 3 logs higher than that among UAD-negative patients ( = 0.036). The nanofluidic Sp-qPCR assay may be accurate and useful for detecting VTPP among adults.
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http://dx.doi.org/10.1128/JCM.01874-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5925721PMC
May 2018

In vivo kinematics of early-stage osteoarthritic knees during pivot and squat activities.

Gait Posture 2017 10 4;58:214-219. Epub 2017 Aug 4.

Department of Mechanical and Aerospace Engineering, University of Florida, 330 MAE-A P.O. Box 116250, Gainesville, FL 32611-6250, USA.

Kinematic changes have been shown to accompany severe knee osteoarthritis, but no studies have analyzed early-stage osteoarthritic knee kinematics in the transverse plane during functional activities. The purpose of this study was to analyze kinematics of early-stage osteoarthritic knees using model registration techniques. Fifteen early-stage osteoarthritic knees from eight females with a mean age of 52 years old (range, 43-57years old) were involved in this study. A radiologist confirmed with plain radiographs that knees had Kellgren-Lawrence grade-1 or -2 arthritic changes. Fluoroscopic images of squat and pivot activities were recorded for each subject. Three-dimensional surface models of the distal femur and proximal tibia were created from CT images, and anatomic coordinate systems were embedded in each model. The three-dimensional position and orientation of the femur and the tibia were determined using model-image registration techniques, and tibial anteroposterior translation and internal/external rotation relative to the femur were calculated. The contact points of the medial and lateral femoral condyle were also computed. Compared to healthy knees, osteoarthritic knees showed lateral contact points that were significantly shifted anteriorly in both pivot (P<0.001) and squat (P=0.001) activities and greater tibial external rotation in pivot activity (P=0.007). The medial contact point location was similar to healthy knees, but the amount of anteroposterior translation was smaller (P<0.001). These kinematic changes might change stress distributions in the medial compartment during weight-bearing activities. The changes in kinematics possibly have some influence on initiation or progression of knee osteoarthritis.
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http://dx.doi.org/10.1016/j.gaitpost.2017.07.116DOI Listing
October 2017

In vivo 3D analysis of clavicular kinematics during scapular plane abduction: comparison of dominant and non-dominant shoulders.

Gait Posture 2014 18;39(1):625-7. Epub 2013 Jul 18.

Department of Mechanical and Aerospace Engineering, University of Florida, 330 MAE-A P.O. Box 116250, Gainesville, FL 32611-6250, USA; Department of Orthopaedic Surgery, Teikyo University Chiba Medical Center, Ichihara, Chiba, Japan. Electronic address:

The purpose of this study was to evaluate side-to-side differences in three-dimensional clavicle kinematics in normal shoulders during dynamic scapular plane elevation using model-image registration techniques. Twelve healthy males with a mean age of 32 years (range, 27-36 years old) were enrolled in this study. Clavicle rotations were computed with bilateral fluoroscopic images and CT-derived bone models using model-image registration techniques and compared between dominant and nondominant shoulders. There was no difference in retraction between both shoulders. The clavicle in dominant shoulders was less elevated during abduction than in nondominant shoulders (P=0.03). Backward rotation angles of dominant shoulders were significantly smaller than those of nondominant shoulders throughout the activity (P=0.03). Clavicular kinematics during scapular plane abduction were different according to hand-dominance.
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http://dx.doi.org/10.1016/j.gaitpost.2013.06.021DOI Listing
July 2014

Development of a novel in silico docking simulation model for the fine HIV-1 cytotoxic T lymphocyte epitope mapping.

PLoS One 2012 27;7(7):e41703. Epub 2012 Jul 27.

Institute of Tropical Medicine, Nagasaki University, Nagasaki City, Nagasaki, Japan.

Introduction: Class I HLA's polymorphism has hampered CTL epitope mapping with laborious experiments. Objectives are 1) to evaluate the novel in silico model in predicting previously reported epitopes in comparison with existing program, and 2) to apply the model to predict optimal epitopes with HLA using experimental results.

Materials And Methods: We have developed a novel in silico epitope prediction method, based on HLA crystal structure and a peptide docking simulation model, calculating the peptide-HLA binding affinity at four amino acid residues in each terminal. It was applied to predict 52 HIV best-defined CTL epitopes from 15-mer overlapping peptides, and its predictive ability was compared with the HLA binding motif-based program of HLArestrictor. It was then used to predict HIV-1 Gag optimal epitopes from previous ELISpot results.

Results: 43/52 (82.7%) epitopes were detected by the novel model, whereas 37 (71.2%) by HLArestrictor. We also found a significant reduction in epitope detection rates for longer epitopes in HLArestrictor (p = 0.027), but not in the novel model. Improved epitope prediction was also found by introducing both models, especially in specificity (p<0.001). Eight peptides were predicted as novel, immunodominant epitopes in both models.

Discussion: This novel model can predict optimal CTL epitopes, which were not detected by an existing program. This model is potentially useful not only for narrowing down optimal epitopes, but predicting rare HLA alleles with less information. By introducing different principal models, epitope prediction will be more precise.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0041703PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3407191PMC
April 2013

Dynamic in vivo glenohumeral kinematics during scapular plane abduction in healthy shoulders.

J Orthop Sports Phys Ther 2012 Feb 25;42(2):96-104. Epub 2011 Oct 25.

Teikyo University Chiba Medical Center, Department of Orthopaedic Surgery, Ichihara, Chiba, Japan.

Study Design: Controlled laboratory study.

Objectives: To measure superior/inferior translation and external rotation of the humerus relative to the scapula during scapular plane abduction using 3-D/2-D model image registration techniques.

Background: Kinematic changes in the glenohumeral joint, including excessive superior translation of the humeral head and inadequate external rotation of the humerus, are believed to be a possible cause of shoulder impingement. Although many researchers have analyzed glenohumeral kinematics with various methods, few articles have assessed dynamic in vivo glenohumeral motion.

Methods: Twelve healthy males with a mean age of 32 years (range, 27-36 years) were enrolled in this study. Fluoroscopic images of the dominant shoulder during scapular plane elevation were taken, and computed tomography-derived 3-D bone models were matched with the silhouette of the bones in the fluoroscopic images using 3-D/2-D model image registration techniques. The kinematics of the humerus relative to the scapula were determined using Euler angles.

Results: On average, there was 2.1 mm of initial humeral translation in the superior direction from the starting position to 105° of humeral elevation. Subsequently, an average of 0.9 mm of translation in the inferior direction occurred between 105° and maximum arm elevation. The average amount of external rotation of the humerus was 14° from the starting position to 60° of humeral elevation. The humerus then rotated internally an average 9° by the time the shoulder reached maximum elevation. These changes in superior/inferior translation and external/internal rotation were statistically significant (P<.001 and P = .001, respectively), based on 1-way repeated-measures analysis of variance.

Conclusion: The observed glenohumeral translations and rotations characterize healthy shoulder function and serve as a preliminary foundation for quantifying pathomechanics in the presence of glenohumeral joint disorders.
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http://dx.doi.org/10.2519/jospt.2012.3584DOI Listing
February 2012

Living-donor lobar lung transplantation for pulmonary alveolar proteinosis in an adult: report of a case.

Surg Today 2011 Aug 20;41(8):1142-4. Epub 2011 Jul 20.

Division of Surgical Oncology, Department of Translational Medical Science, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki, 852-8501, Japan.

A 43-year-old woman with pulmonary alveolar proteinosis (PAP) was successfully treated with living-donor lobar lung transplantation (LDLLT). The patient's PAP had been diagnosed at age 35. She had been treated with repeated bronchoalveolar lavage and granulocyte-macrophage colony-stimulating factor (GM-CSF) inhalation therapy despite having no serum anti-GM-CSF autoantibodies. At age 42, her respiratory condition became critical and she underwent transplantation from two donors. While careful observation was needed for the recurrence of PAP in the transplanted lungs, she was functioning well without oxygen therapy 1 year after transplantation. This appears to be the first report of LDLLT for PAP in an adult.
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http://dx.doi.org/10.1007/s00595-010-4411-0DOI Listing
August 2011

Comparison of MRI-based assessment systems for osteoarthritic knees: the irregularity index system and WORMS.

J Orthop Sci 2011 Jul 12;16(4):369-75. Epub 2011 May 12.

Department of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba, 260-8670, Japan.

Purpose: Several MRI-based evaluation systems for osteoarthritis (OA) of the knee have been developed. Among them the whole-organ magnetic resonance imaging score (WORMS), which evaluates the status of the entire knee joint, appears to be representative. We developed an irregularity index system to measure irregularities of the contours of the femoral condyle on MRI. Only the contour of the condyle was assessed by the irregularity index, whereas several items comprising the knee joint were taken into account by WORMS. This study compared the irregularity index and WORMS in terms of their correlations with clinical scores.

Methods: Thirty-one medial-type OA knees were studied. Kellgren-Lawrence grading was used for X-ray grading: 8 were grade II, 11 were grade III, and 12 were grade IV. Japanese Orthopaedic Association scores and Japanese knee osteoarthritis measure scores were used for clinical assessments. We determined the correlations between MRI-based assessment scores and clinical scores.

Results: Both the irregularity index and WORMS exhibited positive correlations with these clinical scores. The irregularity index was associated with bone cysts of the medial compartment and menisci in the articular features of WORMS.

Conclusions: These MRI-based methods are useful for evaluating OA severity. However, the irregularity index may have advantages over WORMS because of its semi-automatic features.
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http://dx.doi.org/10.1007/s00776-011-0062-2DOI Listing
July 2011

In vivo 3-dimensional analysis of scapular kinematics: comparison of dominant and nondominant shoulders.

J Shoulder Elbow Surg 2011 Jun 30;20(4):659-65. Epub 2010 Dec 30.

Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA.

Background: Alterations in scapular motion frequently are seen in association with various shoulder disorders. It is common clinically to compare the pathological shoulder with the contralateral shoulder, in spite of arm dominance, to characterize the disorder. However, there have been few articles that test the underlying assumption that dominant and nondominant shoulders exhibit comparable dynamic kinematics. The purpose of this study was to compare the 3-dimensional (3-D) scapular kinematics of dominant and nondominant shoulders during dynamic scapular plane elevation using 3-D-2-D (2-dimensional) registration techniques.

Materials And Methods: Twelve healthy males with a mean age of 32 years (range, 27-36) were enrolled in this study. Bilateral fluoroscopic images during scapular plane elevation and lowering were taken, and CT-derived 3-D bone models were matched with the silhouette of the bones in the fluoroscopic images using 3-D-2-D registration techniques. Angular values of the scapula and scapulohumeral rhythm were compared between dominant and nondominant shoulders with statistical analysis.

Results: There was a significant difference in upward rotation angles between paired shoulders (P < .001), while significant differences were not found in the other angular values and scapulohumeral rhythm. The dominant scapulae were 10° more downwardly rotated at rest and 4° more upwardly rotated during elevation compared to the nondominant scapulae.

Discussion/conclusion: Scapular motion was not the same between dominant and nondominant arms in healthy subjects. The dominant scapula was rotated further downward at rest and reached greater upward rotation with abduction. These differences should be considered in clinical assessment of shoulder pathology.
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http://dx.doi.org/10.1016/j.jse.2010.09.012DOI Listing
June 2011

Two cases of synovial haemangioma of the knee joint: Gd-enhanced image features on MRI and arthroscopic excision.

Knee 2011 Dec 30;18(6):509-11. Epub 2010 Oct 30.

Dept. of Orthopaedic Surgery, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan.

Synovial haemangioma of the knee joint is a relatively rare benign condition with around 200 reported cases. We have recently encountered two cases of synovial haemangioma of the knee joint which preoperative MRI had assessed as highly suspect and which arthroscopic resection and subsequent histological examinations confirmed as synovial hemangiomas. Published studies have identified the following as characteristic MRI features of synovial haemangioma: homogenous low intensity to iso-intensity on T1 sequence; and heterogeneous high intensity with low-intensity septa or spots within the lesion on T2 sequence. However, several other intra-knee disorders mimic these characteristics. In our two cases, we found that gadolinium (Gd)-enhanced images, which have been relatively rarely discussed in the literature, were useful for making the diagnosis and for determining the extent of this condition. These images also were very helpful during arthroscopic excision of the lesion. Nonetheless, even after Gd enhancement, differentiating between malignant conditions such as synovial sarcoma and haemangioma solely from MRI findings is still difficult.
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http://dx.doi.org/10.1016/j.knee.2010.10.004DOI Listing
December 2011

In vivo 3D kinematics of normal forearms: analysis of dynamic forearm rotation.

Clin Biomech (Bristol, Avon) 2010 Dec 8;25(10):979-83. Epub 2010 Aug 8.

Department of Mechanical and Aerospace Engineering, University of Florida, 330 MAE-A PO Box 116250, Gainesville, FL 32611-6250, USA.

Background: Forearm rotation is an indispensable activity of daily living and comprises complex motions with rotational and translational components. It is thought that changes in these motions with injury or disease may affect diagnostic indices. Several studies have assessed in vivo forearm kinematics with static conditions, but dynamic forearm kinematics have not yet been reported. The purpose of this study was to analyze forearm kinematics during dynamic rotation using radiographic 3D-2D registration methods.

Methods: Ten forearms of five healthy males with the mean age of 37 years old were enrolled. Lateral fluoroscopic images were taken during forearm rotation from maximum supination to maximum pronation with their elbows flexed to approximately 45°. Geometric bone models were created from CT scans of the humerus, the radius and the ulna. Three-dimensional kinematics were determined using 3D-2D model registration techniques with the images and models, and the arc of axial rotation of the radius, volar/dorsal translation of the ulna at the distal radioulnar joint and rotation axis of forearm were computed.

Findings: The radial rotation arc was 157°. The ulna translated 3.9 mm (SD 1.5mm) dorsally during activity. The rotation axis of the forearm passed through the center of the radial head and the ulnar head at the 1.9 mm (SD 0.7 mm) posterior from its geometric centroid.

Interpretation: The posteriorly deviated rotation axis at the ulnar head may result in the ulnar head translating dorsally during pronation. These data provide a basis for objective assessment of pathological forearm function.
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http://dx.doi.org/10.1016/j.clinbiomech.2010.07.006DOI Listing
December 2010

Objective assessments of medial osteoarthritic knee severity by MRI: new computer software to evaluate femoral condyle contours.

Int Orthop 2010 Aug 8;34(6):811-7. Epub 2009 Sep 8.

Department of Orthopedic Surgery, Graduate School of Medicine, Chiba University, Chuo-ku, Chiba, Japan.

An irregular contour of the medial femoral condyle (MFC) on magnetic resonance imaging (MRI) appears to indicate the severity of medial-type knee osteoarthritis (OA). The purpose of this study was to establish a system to enable objective assessments of OA knee severity using newly developed software that semi-automatically measures irregularity of the MFC. (1) We evaluated 48 patients aged 50-83 years with 55 knees of medial-type OA. The following scores were recorded: Lysholm score, visual analogue scale (VAS) and the Japanese Knee Osteoarthritis Measure (JKOM). MFC irregularity was automatically calculated by newly programmed computer software. Four parameters for condyle irregularity were calculated: (a) the average thickness of the contour (ATC), (b) the ratio of the upper surface length to the lower surface length of the contour (RUL), (c) average squared thickness of the contour (ASTC) and (d) standard deviation of the contour thickness (SDC). (2) Nine knees that underwent total knee arthroplasty were further analysed histopathologically and compared with irregularity score. Statistically, the RUL and SDC were significantly correlated with the Lysholm score, VAS and JKOM, with good reliability. Histological examinations showed that an irregular contour reflected the density of cystic lesions formed in subchondral bone. An irregularity of MFC on MRI is correlated with OA disease severity clinically and histopathologically. The new computer software is useful to objectively assess OA disease severity.
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http://dx.doi.org/10.1007/s00264-009-0864-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989011PMC
August 2010