Publications by authors named "Mitsuyuki Nagashima"

7 Publications

  • Page 1 of 1

Dynamic analysis of the ulnar nerve and cubital tunnel morphology using ultrasonography; A cadaveric study.

J Shoulder Elbow Surg 2022 Jul 8. Epub 2022 Jul 8.

Department of Orthopedic Surgery, Nara Medical University, Kashihara, Japan.

Background: The causes of ulnar neuropathy at the elbow are unclear. The authors hypothesized that the humeral trochlea protrudes into the cubital tunnel during elbow flexion and causes a dynamic morphologic change of the ulnar nerve in the cubital tunnel.

Methods: An ultrasonic probe was fixed to the ulnar shafts of 10 fresh cadavers with an external fixator, and dynamic morphology of the cubital tunnel and ulnar nerve was observed. The distance from the Osborne band to the trochlea (OTD), distance from ulnar nerve center to the trochlea (UTD), and short and long axis diameters of the nerve at 30°, 60°, 90°, 120° of elbow flexion were recorded. We compared the OTD, UTD, and the flattening of the ulnar nerve between angle of flexion using single factor analysis of variance. Correlation between the ulnar nerve flattering, OTD, and UTD was examined using Spearman's correlation coefficient. A p value less than 0.05 was used to denote statistical significance.

Results: Flattening of the ulnar nerve progressed with increasing elbow flexion and was significantly different between 0° and 60°, 90°, and 120° (p = 0.03 at 60º, p < 0.01 at 90º and 120º). OTD decreased with elbow flexion, and there was a significant difference among all elbow flexion angles (all p < 0.01). UTD decreased significantly from 0° flexion value to 90° flexion value (p = 0.03). Flattering of the nerve was significantly correlated with the OTD (r = 0.66, p < 0.01).

Conclusions: A positive correlation was found between the protrusion of the humeral trochlea into the cubital tunnel during elbow flexion and ulnar nerve flattening using cadaveric elbow and ultrasonography.
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http://dx.doi.org/10.1016/j.jse.2022.05.026DOI Listing
July 2022

Simultaneous Bilateral Chronic Volar Lunate Dislocation: A Case Report.

JBJS Case Connect 2022 04 15;12(2). Epub 2022 Jun 15.

Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Nara, Japan.

Case: A 24-year-old professional judo competitor suffered injuries to both the wrists when he fell on his back while lifting a 90-kg barbell in the bilateral dorsiflexed wrist position. Simultaneous bilateral volar lunate dislocation had been missed for a year. The degenerated lunates were simultaneously removed using a palmar approach. At 12 months postoperatively, the patient returned to judo competitions without pain. Radiography showed no progression of the intercarpal alignment abnormality.

Conclusion: Simultaneous bilateral chronic volar lunate dislocation is extremely rare. Long-term follow-up is necessary to check for carpal alignment.
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http://dx.doi.org/10.2106/JBJS.CC.22.00094DOI Listing
April 2022

Acromioclavicular joint instability on cross-body adduction view: the biomechanical effect of acromioclavicular and coracoclavicular ligaments sectioning.

BMC Musculoskelet Disord 2022 Mar 23;23(1):279. Epub 2022 Mar 23.

Department of Orthopedic Surgery, Nara Medical University, 840 Shijoutyou, Kashihara City, Nara, 634-5821, Japan.

Background: The acromioclavicular (AC) and coracoclavicular (CC) ligaments are important stabilizers of the AC joint. We hypothesized that AC and trapezoid ligament injuries induce AC joint instability and that the clavicle can override the acromion on cross-body adduction view even in the absence of conoid ligament injury. Accordingly, we investigated how sectioning the AC and CC ligaments contribute to AC joint instability in the cross-body adduction position.

Methods: Six fresh-frozen cadaveric shoulders were used in this study, comprising five male and one female specimen, with a mean age of 68.7 (range, 51-87) years. The left side of the trunk and upper limb, and the cervical and thoracic vertebrae and sternum were firmly fixed with an external fixator. The displacement of the distal end of the clavicle relative to the acromion was measured using an electromagnetic tracking device. We simulated AC joint dislocation by the sequential resection of the AC ligament, AC joint capsule, and CC ligaments in the following order of stages. Stage 0: Intact AC and CC ligaments and acromioclavicular joint capsule; stage 1: Completely sectioned AC ligament, capsule and joint disc; stage 2: Sectioned trapezoid ligament; and stage 3: Sectioned conoid ligament. The superior clavicle displacement related to the acromion was measured in the horizontal adduction position, and clavicle overriding on the acromion was assessed radiologically at each stage. Data were analyzed using a one-way analysis of variance and post-hoc tests.

Results: Superior displacement was 0.3 mm at stage 1, 6.5 mm at stage 2, and 10.7 mm at stage 3. On the cross-body adduction view, there was no distal clavicle overriding at stages 0 and 1, and distal clavicle overriding was observed in five cases (5/6: 83%) at stage 2 and in six cases (6/6: 100%) at stage 3.

Conclusion: We found that AC and trapezoid ligament sectioning induced AC joint instability and that the clavicle could override the acromion on cross-body adduction view regardless of conoid ligament sectioning. The traumatic sections of the AC and trapezoid ligament may lead to high grade AC joint instability, and the distal clavicle may subsequently override the acromion.
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http://dx.doi.org/10.1186/s12891-022-05245-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8943985PMC
March 2022

Arthroscopic Lunate Excision Provides Excellent Outcomes for Low-Demand Patients with Advanced Kienböck's Disease.

Arthrosc Sports Med Rehabil 2021 Oct 28;3(5):e1387-e1394. Epub 2021 Aug 28.

Department of Orthopedic Surgery, Nara Medical University, Nara, Japan.

Purpose: To examine the clinical outcomes of arthroscopic lunate excisions for advanced Kienböck's disease.

Methods: Fifteen patients (six men and nine women; mean age: 65 years; range: 48-83 years) with advanced Kienböck's disease, who underwent arthroscopic lunate resection between April 2008 and March 2016, were reviewed clinically and radiographically after a follow-up of >2 years (mean: 29 months; range: 24-60 months). Clinical parameters, such as wrist range of motion, grip strength, Disabilities of the Arm, Shoulder, and Hand (DASH) score, and patient-rated wrist evaluation (PRWE) score were evaluated. Radiographic parameters included radioscaphoid angle, scaphocapitate angle, carpal height ratio, ulnar-triquetrum distance, and the scaphoid-triquetrum distance. Wilcoxon's signed-rank test was used to compare measurement results.

Results: During the final follow-up, patients exhibited significant improvements, such as 42.9° in wrist range of motion ( = .009), 24.5% of the contralateral side in grip strength ( = .001), 26.2 points in DASH score ( = .002), and 37.8 points in PRWE score ( .001), compared with the preoperative values. The radioscaphoid and scaphocapitate angles significantly increased by 4.8° ( = .0027) and 3.7° ( = .0012), respectively. The carpal height ratio, ulnar-triquetrum distance, and scaphoid-triquetrum distance significantly decreased by 0.05 ( .001), 2.6 mm ( .001), and 1.3 mm ( = .0012), respectively.

Conclusions: Our results suggest that arthroscopic lunate excisions provided excellent postoperative pain relief and functional recovery within 2 years of follow-up. Changes in carpal alignment and stress concentration on the radial side of the carpal bones could occur in the long term; however, arthroscopic lunate excision can be a good surgical option for treating low-demand patients with advanced Kienböck's disease.

Level Of Evidence: Level IV, therapeutic case series.
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http://dx.doi.org/10.1016/j.asmr.2021.06.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8527252PMC
October 2021

Treatment of painful median nerve neuroma using pedicled vascularized lateral antebrachial cutaneous nerve with adipofascial flap: a cadaveric study and exploration of clinical application.

J Plast Surg Hand Surg 2022 Apr 9;56(2):74-78. Epub 2021 Jun 9.

Department of Orthopaedic Surgery, Nara Medical University, Kashihara, Japan.

The most common procedure for the treatment of painful median nerve neuroma is coverage with vascularized soft tissue following external neurolysis. However, the ideal treatment should include reconnecting the proximal and distal stumps of the damaged nerve to allow the growth of regenerating axons to their proper targets for a functional recovery. We developed a useful technique employing radial artery perforator adipofascial flap including the lateral antebrachial cutaneous nerve (LABCN) to repair the median nerve by vascularized nerve grafting and to achieve coverage of the nerve with vascularized soft tissue. In an anatomical study of 10 fresh-frozen cadaver upper extremities, LABCN was constantly bifurcated into two branches at the proximal forearm (mean: 8.2 cm distal to the elbow) and two branches that run in a parallel manner toward the wrist. The mean length of the LABCN branches between the bifurcating point and the wrist was 18.2 cm, which enabled inclusion of adequate length of the LABCN branches into the radial artery perforator adipofascial flap. The diameters of the LABCN branches (mean: 1.7 mm) were considered suitable to bridge the funiculus of the median nerve defect after microsurgical internal neurolysis. In all cadaver upper extremities, the 3-cm median nerve defect at the wrist level could be repaired using the LABCN branches and covered with the radial artery perforator adipofascial flap. On the basis of this anatomical study, the median nerve neuroma was successfully treated with radial artery perforator adipofascial flap including vascularized LABCN branches.
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http://dx.doi.org/10.1080/2000656X.2021.1933994DOI Listing
April 2022

Biomechanical comparison of arthroscopic and open lunate excisions in the cadaveric wrist.

Clin Biomech (Bristol, Avon) 2021 04 26;84:105343. Epub 2021 Mar 26.

Department of Orthopaedic Surgery, Nara Medical University, 840 Shijo-cho, Kashihara, Nara, Japan.

Background: In advanced Kienböck disease, unreconstructible lunate should be excised as a salvage procedure. There is a lack of information about the biomechanical approaches evaluating the carpal kinematics after lunate excision. We hypothesized that arthroscopic lunate excision would not break the ring structure of the proximal carpal row, preventing carpal instability. We aimed to investigate changes in carpal kinematics following arthroscopic and open lunate excisions.

Methods: We used upper extremities from five fresh cadavers and simulated arthroscopic and open lunate excisions. Arthroscopic lunate excision was performed to preserve the attachment sites of intrinsic and extrinsic carpal ligaments to the lunate. Open lunate excision was conducted with sectioning of the intrinsic and extrinsic carpal ligaments. Using a three-dimensional space electromagnetic tracking device, rotation angles of the scaphoid and triquetrum and the change of scaphotriquetrum distance were measured under axial loading. We compared the rotation angles and the change of scaphotriquetrum distance among intact wrists, open, and arthroscopic lunate excisions.

Findings: No Significant differences in the rotation angle of the scaphoid and triquetrum or the change of scaphotriquetrum distance were found between intact wrist and arthroscopic lunate excision. The triquetrum significantly dorsiflexed and supinated in wrists with open lunate excisions compared with intact wrists. Significant differences in the change of scaphotriquetrum distance were found between intact and openly excised wrists and between arthroscopic and open excisions.

Interpretation: Arthroscopic lunate excision potentially prevented kinematic change of the proximal carpal row under axial loading by maintaining the integrity of attachment sites of carpal ligaments.
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http://dx.doi.org/10.1016/j.clinbiomech.2021.105343DOI Listing
April 2021

Impacted intraarticular fragments of distal radius fractures: A radiographic characterization and analysis of reliability and diagnostic accuracy.

J Orthop Sci 2022 Mar 9;27(2):384-388. Epub 2021 Mar 9.

Department of Orthopedic Surgery, Nara Medical University, Kashihara, Nara, 634-8522, Japan.

Background: Reduction using ligamentotaxis may not be effective enough to treat impacted intraarticular fragments of distal radius fractures. Articular incongruence resulting from the loss of reduction is a risk factor for postoperative osteoarthritis and worse clinical outcome. This study aimed to analyze the radiographic characterization of the impacted intraarticular fragments of distal radius fractures using two/three-dimensional computed tomography (CT). Further, we assessed the reliability and diagnostic accuracy in detecting the fragments using plain radiographs.

Methods: We analyzed 167 three-dimensional CT images of the intraarticular distal radius fractures and selected 12 fractures with impacted intraarticular fragments. We recorded the location, size, and displacement of the fragment using CT images. In addition, six examiners evaluated 25 fractures including those 12 fractures having the fragments using plain radiographs for detecting the fragments and their displacements. Further, we evaluated the reliability and diagnostic accuracy of the plain radiographs in the detection of the fragment.

Results: Fifteen impacted intraarticular fragments were found in 12 wrists. The displacement of the scaphoid facet fragment was significantly larger than that of the lunate facet fragment in CT measurement (7.0 mm and 3.6 mm). Inter and intraobserver reliability of the diagnosis for the fragment in plain radiographs were poor and fair (κ: 0.14 and κ:0.27). Diagnostic accuracy in detecting the fragment in plain radiographs generated mean sensitivity: 0.4, mean specificity: 0.73, and mean accuracy: 0.58. The mean sensitivity in detecting a lunate facet fragment was lower than that of a scaphoid facet fragment in plain radiographs (0.24 and 0.44).

Conclusion: Impacted intraarticular fragments were found in 7% of intraarticular distal radius fractures. We observed low reliability and sensitivity in detecting the fragment using plain radiographs. Preoperative recognition of the fragments using plain radiograph were difficult, even though the magnitude of step-off of the scaphoid facet fragment was large.
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http://dx.doi.org/10.1016/j.jos.2020.12.029DOI Listing
March 2022
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