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Dive into the research topics where Katsuyuki Iwatsuki is active.

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Featured researches published by Katsuyuki Iwatsuki.


PLOS ONE | 2013

Targeting Anti-Inflammatory Treatment Can Ameliorate Injury-Induced Neuropathic Pain

Katsuyuki Iwatsuki; Tetsuya Arai; Hideyuki Ota; Shuichi Kato; Tadahiro Natsume; Shigeru Kurimoto; Michiro Yamamoto; Hitoshi Hirata

Tumor necrosis factor-α plays important roles in immune system development, immune response regulation, and T-cell-mediated tissue injury. The present study assessed the net value of anti-tumor necrosis factor-α treatment in terms of functional recovery and inhibition of hypersensitivity after peripheral nerve crush injury. We created a right sciatic nerve crush injury model using a Sugita aneurysm clip. Animals were separated into 3 groups: the first group received only a skin incision; the second group received nerve crush injury and intraperitoneal vehicle injection; and the third group received nerve crush injury and intraperitoneal etanercept (6 mg/kg). Etanercept treatment improved recovery of motor nerve conduction velocity, muscle weight loss, and sciatic functional index. Plantar thermal and von Frey mechanical withdrawal thresholds recovered faster in the etanercept group than in the control group. On day 7 after crush injury, the numbers of ED-1-positive cells in crushed nerves of the control and etanercept groups were increased compared to that in the sham-treated group. After 21 days, ED-1-positive cells had nearly disappeared from the etanercept group. Etanercept reduced expression of interleukin-6 and monocyte chemotactic and activating factor-1 at the crushed sciatic nerve. These findings demonstrate the utility of etanercept, in terms of both enhancing functional recovery and suppressing hypersensitivity after nerve crush. Etanercept does not impede the onset or progression of Wallerian degeneration, but optimizes the involvement of macrophages and the secretion of inflammatory mediators.


Journal of Bone and Joint Surgery-british Volume | 2013

Simple debridement has little useful value on the clinical course of recalcitrant ulnar wrist pain

Takanobu Nishizuka; Masahiro Tatebe; Hitoshi Hirata; Takaaki Shinohara; Michiro Yamamoto; Katsuyuki Iwatsuki

The purpose of this study was to evaluate treatment results following arthroscopic triangular fibrocartilage complex (TFCC) debridement for recalcitrant ulnar wrist pain. According to the treatment algorithm, 66 patients (36 men and 30 women with a mean age of 38.1 years (15 to 67)) with recalcitrant ulnar wrist pain were allocated to undergo ulnar shortening osteotomy (USO; n = 24), arthroscopic TFCC repair (n = 15), arthroscopic TFCC debridement (n = 14) or prolonged conservative treatment (n = 13). The mean follow-up was 36.0 months (15 to 54). Significant differences in Hand20 score at 18 months were evident between the USO group and TFCC debridement group (p = 0.003), and between the TFCC repair group and TFCC debridement group (p = 0.029). Within-group comparisons showed that Hand20 score at five months or later and pain score at two months or later were significantly decreased in the USO/TFCC repair groups. In contrast, scores in the TFCC debridement/conservative groups did not decrease significantly. Grip strength at 18 months was significantly improved in the USO/TFCC repair groups, but not in the TFCC debridement/conservative groups. TFCC debridement shows little benefit on the clinical course of recalcitrant ulnar wrist pain even after excluding patients with ulnocarpal abutment or TFCC detachment from the fovea from the indications for arthroscopic TFCC debridement.


Global Spine Journal | 2015

Spontaneously Resolved Recurrent Cervical Epidural Hematoma in a 37-Week Primigravida.

Katsuyuki Iwatsuki; Masao Deguchi; Hitoshi Hirata; Toshihisa Kanamono

Study Design Case report. Objective To describe a patient with a recurrent spontaneous spinal epidural hematoma (SSEH) during pregnancy that had spontaneous remission. Methods A 27-year-old primigravida at 37 weeks’ gestation suddenly felt a strong left shoulder pain without any trauma. She had a history of fenestration for a spontaneous cervical hematoma when she was 18 years old. An emergency magnetic resonance imaging revealed a recurrence of the cervical epidural hematoma at the C4–T1 level, but she had no paralysis. Results The patient subsequently underwent a cesarean section and delivered a healthy male infant. Her spinal epidural hematoma disappeared. Multislice computed tomography showed no evidence for a vascular malformation or tumor. Three years after the initial cesarean section, she underwent a second one and delivered another male infant. Conclusions We report on a rare case of recurrent SSEH during pregnancy with no neurologic deficits that was treated nonoperatively with close observation and resulted in spontaneous resolution. In such patients with no neurologic deficits, nonoperative management with close observation may be a reasonable alternative.


Pain | 2014

Pathological mechanism of musculoskeletal manifestations associated with CRPS type II: An animal study

Hideyuki Ota; Tetsuya Arai; Katsuyuki Iwatsuki; Hideki Urano; Toshikazu Kurahashi; Shuichi Kato; Michiro Yamamoto; Hitoshi Hirata

&NA; Vicarious facilitation of responses to pain at the spinal level can be diminished by top‐down attentional processes directed toward meaning of expressions. &NA; Patients with complex regional pain syndrome (CRPS) often complain of abnormal sensations beyond the affected body part, but causes of this spread of musculoskeletal manifestations into contiguous areas remain unclear. In addition, immobilization can predispose to the development of CRPS. We examined functional, biochemical, and histological alterations in affected parts, including contiguous zones, using an animal model. Ten‐week‐old male Wistar rats were assigned to 5 groups: a normal group receiving no treatment, a sham operation group with surgical exploration, an immobilization group with surgical exploration plus internal knee joint immobilization, a surgical neuropathy group prepared by spinal nerve ligation (SNL) of the left L5 nerve root, and a surgical neuropathy + immobilization group with simultaneous SNL and knee joint immobilization. Mechanical allodynia and knee contracture were compared between groups, and tissues were harvested for histological assessments and gene and protein expression analyses. Neither surgical procedures nor immobilization induced detectable mechanical sensitivity. However, the addition of nerve injury resulted in detectable mechanical allodynia, and immobilization not only accelerated hyperalgesia, but also resulted in muscle fibrosis. Nerve growth factor (NGF) and other mediators of neurogenic inflammation were highly expressed not only in denervated muscles, but also in innervated muscles in contiguous areas, suggesting the spread of NGF production beyond the myotome of the injured nerve. Transforming growth factor &bgr; was involved in the development of contracture in CRPS. These findings imply that neuroinflammatory components play major roles in the progression and dispersion of both sensory pathologies and pathologies that are exacerbated by immobilization.


Journal of Hand Surgery (European Volume) | 2014

Comparative responsiveness of the Hand 20 and the DASH-JSSH questionnaires to clinical changes after carpal tunnel release:

Katsuyuki Iwatsuki; K. Nishikawa; M. Chaki; A. Sato; Akimasa Morita; Hitoshi Hirata

This study compared the responsiveness of the Hand 20 and the Japanese version of the disabilities of the arm, shoulder and hand (DASH-JSSH) questionnaires in carpal tunnel syndrome. The scores before and 3 months after surgery were used to calculate the standardized response mean and effect size. Of 57 patients enrolled in the study, 13 underwent open carpal tunnel release and 44 had endoscopic carpal tunnel release. The standardized response mean and the effect size of the Hand 20 scale were 0.60 and 0.54, respectively, and those of the disabilities of the arm, shoulder and hand scale were 0.39 and 0.36, respectively. Compared with the Disabilities of the Arm, Shoulder and Hand questionnaire, the Hand 20 questionnaire appears to have better responsiveness for assessing the effect of treatment by carpal tunnel release.


Journal of Hand Surgery (European Volume) | 2014

Ulnar impaction syndrome: incidence of lunotriquetral ligament degeneration and outcome of ulnar-shortening osteotomy.

Katsuyuki Iwatsuki; Masahiro Tatebe; Michiro Yamamoto; Takaaki Shinohara; Ryogo Nakamura; Hitoshi Hirata

PURPOSE We hypothesized that most patients with ulnar impaction syndrome have degenerative changes of the proximal lunotriquetral (LT) membrane and that ulnar-shortening osteotomy is an effective procedure in these patients. METHODS We retrospectively reviewed 50 wrists of 49 patients with idiopathic ulnar impaction syndrome who underwent an arthroscopic evaluation at the time of ulnar-shortening osteotomy, and subsequently at plate removal. Based on the Geissler classification, patients were divided into group A, normal, and group B, grades I to IV. The degree of degeneration of the proximal LT membrane at first-look arthroscopy was compared with that at second-look arthroscopy. RESULTS After ulnar-shortening osteotomy, both groups improved significantly in wrist range of motion and grip strength. According to the Mayo wrist score, 29, 18, and 3 patients showed excellent, good, and fair results, respectively. Of the 50 wrists, 25 had degenerative changes (group B) in the proximal LT membrane at the time of first-look arthroscopy. Of the 25 wrists in group B, 11 wrists improved based on the Geissler grade, 9 wrists showed no changes, and 2 wrists became worse. Clinically, patients demonstrated improvement after ulnar-shortening osteotomy regardless of the degree of degenerative LT ligament changes. CONCLUSIONS Degenerative LT membrane changes that were seen in about half of our patients were mostly of a mild nature, and the clinical outcomes of ulnar-shortening osteotomy were acceptable. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.


Journal of Orthopaedic Research | 2016

Interindividual anatomical variations affect the plate-to-bone fit during osteosynthesis of distal radius fractures.

Hidemasa Yoneda; Katsuyuki Iwatsuki; Tatsuya Hara; Shigeru Kurimoto; Michiro Yamamoto; Hitoshi Hirata

We hypothesized that interindividual variations in the teardrop, which represents the volar projection of the lunate facet of the distal radius, cause unsatisfactory fitting of the volar locking plate to the bone. This can cause flexor tendon ruptures. Herein, we conducted a cross‐sectional study and measured the ratio of teardrop height and the teardrop inclination angle as parameters of teardrop configuration for 200 standardized lateral radiographs (average age of the patients, 51 years). We also quantified the influence of the teardrop morphology by analyzing the fit of three locking plates to three radii with differing teardrop inclination angles using a three‐dimensional computer‐aided design system. The average ratios of the teardrop height and teardrop inclination angle were 0.42° (0.30–0.56°) and 28.8° (9.9–44.9°), respectively. The teardrop inclination angle was moderately correlated with age in men but not in women. In the plate‐to‐bone fit analyses, the fit of all the plates was significantly different between bones, with the configuration of the radius with the lowest teardrop inclination angle being the closest approximation to that of each plate. We demonstrated the interindividual variation in the shape of the teardrop and its influence on the fit of the volar plate, highlighting the importance of careful plate selection for achieving osteosynthesis of bones with a high teardrop inclination angle.


Clinical Neurology and Neurosurgery | 2016

Anterior interosseous nerve and posterior interosseous nerve involvement in neuralgic amyotrophy

Mao Akane; Katsuyuki Iwatsuki; Masahiro Tatebe; Takanobu Nishizuka; Shigeru Kurimoto; Michiro Yamamoto; Hitoshi Hirata

OBJECTIVES The aim of this study was to gain a better understanding of anterior interosseous nerve and posterior interosseous nerve involvement in neuralgic amyotrophy. METHODS In a retrospective chart review, 51 cases (49 patients) with anterior and posterior interosseous nerve syndrome were investigated in terms of their symptoms, course of disease, and prognosis. RESULTS Patients first presented with pain in 52.9% of cases. The location of the pain was distal to the shoulder in most cases (85.1%). Sensory involvement was found in 27.5% of patients, and patients with pain before paresis had fewer sensory symptoms (p=0.006). Neurolysis significantly improved Hand20 scores, but conservative treatment did not (p=0.020 vs. 0.204). CONCLUSIONS Patients with anterior interosseous nerve and posterior interosseous nerve affection in neuralgic amyotrophy had less pain. Neurolysis can be superior to conservative treatment in the patients with focal constrictions and no spontaneous recovery.


Microsurgery | 2014

Prostaglandin E1 alleviates neuropathic pain and neural dysfunction from entrapment neuropathy associated with diabetes mellitus.

Tadahiro Natsume; Katsuyuki Iwatsuki; Takanobu Nishizuka; Tetsuya Arai; Michiro Yamamoto; Hitoshi Hirata

In this report, we present the results of investigation of the effects of prostaglandin E1 (PGE1) on entrapment neuropathy using a diabetic rat. A total of 60 male Sprague‐Dawley rats were used in the study. The model of tibial nerve entrapment neuropathy associated with diabetes mellitus was created by streptozotocin‐induced diabetic rats reared in cages with wire grid flooring. Rats were assigned to four groups: nondiabetic (n = 15), untreated diabetic (n = 15), diabetic treated with 30 μg/kg PGE1 (n = 15), and diabetic treated with 100 μg/kg PGE1 (n = 15). Pain tests and electrophysiological tests were performed at 0, 2, and 4 weeks, and assessments of gait, histology, and mRNA expression levels were performed at 4 weeks after initiating the PGE1 administration. In the 30 and 100 μg groups, the mechanical withdrawal thresholds measured by pain tests at 4 weeks (36.2 ± 16.4 g and 31.7 ± 15.3 g, respectively) and the motor conduction velocity (24.0 ± 0.2 m/s and 24.4 ± 0.3 m/s, respectively) were significantly higher than the untreated diabetic group (all P < 0.05) and lower than the nondiabetic group (all P < 0.001). In the gait analysis, the mean intensities in the 30 and 100 μg group (128.0 ± 20.1 a.u. and 109.0 ± 27.8 a.u., respectively) were significantly higher than the untreated diabetic (P < 0.01) and were not significantly different from the nondiabetic group (P = 0.81). Fiber density (P = 0.46) and fiber diameter (P = 0.15) did not show any significant differences. PGE1 significantly decreased nerve growth factor (NGF) mRNA and increased vascular endothelial growth factor (VEGF) mRNA in the tibial nerve (both P < 0.01). In conclusion, neurological deteriorations of diabetic rats were alleviated with PGE1, which is associated with inhibition of NGF and enhancement of VEGF at the entrapment site.


Journal of Bone and Joint Surgery-british Volume | 2016

Effects of depression and inflammatory factors on chronic conditions of the wrist

Masahiro Tatebe; Katsuyuki Iwatsuki; Hitoshi Hirata; T. Oguchi; K. Tanaka; S. Urata

AIMS Chronic conditions of the wrist may be difficult to manage because pain and psychiatric conditions are correlated with abnormal function of the hand. Additionally, intra-articular inflammatory cytokines may cause pain. We aimed to validate the measurement of inflammatory cytokines in these conditions and identify features associated with symptoms. PATIENTS AND METHODS The study included 38 patients (18 men, 20 women, mean age 43 years) with a chronic condition of the wrist who underwent arthroscopy. Before surgery, the Self-Rating Depression Scale (SDS), Hand20 questionnaire and a visual analogue scale (VAS) for pain were used. Cytokine and chemokine levels in the synovial fluid of the wrist were measured using enzyme-linked immunosorbent assays and correlations between the levels with pain were analysed. Gene expression profiles of the synovial membranes were assessed using quantitative polymerase chain reaction. RESULTS Older patients had high pre-operative Hand20 scores. One-year post-operative Hand20 and VAS scores and pre-operative VAS scores correlated with SDS scores. Post-operative VAS scores negatively correlated with the expression of nerve growth factor and SDS scores positively correlated with the expression of tumour necrosis factor-alpha and negatively correlated with the expression of tumour necrosis factor-converting enzyme. CONCLUSION There was a positive correlation between depression and chronic conditions of the wrist. Levels of some cytokines correlate with pain and depression. Additionally, cytokines may be important in the assessment and treatment of chronic conditions of the wrist and depression. Cite this article: Bone Joint J 2016;98-B:961-8.

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