Shota Ikegami

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Papers by Shota Ikegami

Mini Open Foraminotomy for Cervical Radiculopathy: A Comparison of Large Tubular and TrimLine Retractors

Asian spine journal, 2015

Retrospective chart review. A comparison of mini open foraminotomy (MOF) for cervical radiculopat... more Retrospective chart review. A comparison of mini open foraminotomy (MOF) for cervical radiculopathy using either large tubular (LT) or TrimLine (TL) retractors. Posterior foraminotomy relieves compression of the cervical nerve root in radiculopathy patients. However, invasion of the paravertebral muscle may cause major problems in these patients. To address these problems, we performed MOF. Twenty cervical radiculopathy patients (16 male and 4 female) who underwent MOF between May 2004 and August 2011 were assigned to LT and TL groups. Each group contained 10 subjects. Surgical and clinical outcomes were compared. The average operating time in the TL group was significantly shorter than that in the LT group. The final follow-up mean neck disability indices significantly improved compared to the preoperative values (LT group, 12.0±7.8 vs. 28.0±9.4; TL group, 6.0±5.9 vs. 21.9±10). The final follow-up neck pain visual analog scale (VAS) scores also decreased significantly from the preo...

The Pathophysiology and Progression of Hip Osteoarthritis Accompanied with Joint Pain are Potentially Due to Bone Alterations - Follow-up Study of Hip OA Patients

The open rheumatology journal, 2014

This study examined hip osteoarthritis (OA) patients with joint pain and accompanying signal chan... more This study examined hip osteoarthritis (OA) patients with joint pain and accompanying signal changes detected by magnetic resonance imaging (MRI). A total of 19 hip OA patients with suddenly occurring or worsening pain regardless of Kellgren-Lawrence grading were enrolled. The patients were monitored using MRI, plain radiographs, and the Denis pain scale for a minimum of 6 months. The patients were classified into 2 groups: those whose pain improved during conservative treatment (Group A) and those whose pain persisted (Group B). Joint pain disappeared or was markedly improved in all 10 cases in Group A. Radiographic OA progression occurred in 7 of 8 cases with available radiographs. Hip MRI was performed on 7 of 10 patients, among whom bone signal changes disappeared in 6 patients. One patient exhibited persisting bone signal alterations although joint pain had completely disappeared. In Group B, joint pain remained in all 9 cases. Radiographic OA progression occurred in 8 of 9 cas...

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Skip pedicle screw fixation combined with Ponte osteotomy for adolescent idiopathic scoliosis

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2014

This study aimed to determine whether Ponte osteotomy combined with skip pedicle screw fixation (... more This study aimed to determine whether Ponte osteotomy combined with skip pedicle screw fixation (SPSF) can improve the correction rate and restore thoracic kyphosis for patients with adolescent idiopathic scoliosis. Surgical time, blood loss, preoperative Cobb angle of the main thoracic curve, flexibility, Cobb angle at 1 year after surgery, thoracic curve correction rate, and Cincinnati correction index (CCI) were determined for both the Ponte (n = 17) and non-Ponte (control; n = 21) groups. Furthermore, kyphotic angles at T5-T12 before and 1 year after the surgery were measured. The following measurements were obtained for the Ponte and control groups, respectively: surgical time, 236 ± 13 and 187 ± 9 min; blood loss, 1,141 ± 150 and 745 ± 120 g; preoperative Cobb angle of the main thoracic curve, 52.5° ± 10.4° and 51.5° ± 9.2°; flexibility, 31.7 ± 13.2 and 45.1 ± 12.3% (p = 0.003); thoracic curve correction rate, 62.0 ± 2.5 and 63.6 ± 2.5%; CCI, 2.2 ± 0.2 and 1.5 ± 0.1 (p = 0.003...

Perforation Rates of Cervical Pedicle Screw Insertion by Disease and Vertebral Level

The Spine Journal, 2010

Different perforation rates for cervical pedicle screws by disease are expected in relation to bo... more Different perforation rates for cervical pedicle screws by disease are expected in relation to bone quality and pedicle morphology; however, no report comparing pedicle screw perforation rate by disease had previously been published. This study investigated the perforation rates of pedicle screws inserted to cervical pedicle by disease and vertebral level using a CT-based navigation system. Fifty-three patients who underwent cervical pedicle screw insertion using CT based navigation system were studied. Diseases included rheumatoid arthritis (RA) (24 cases), destructive spondyloarthropathy (DSA) (10), cervical spondylotic myelopathy (CSM) (9), spine tumor (6), and cervical spondylotic myelopathy associated with athetoid cerebral palsy (CP) (4). Screw perforation rates for cervical pedicle screws were studied. Major perforation was defined as perforation 50% of screw diameter or more. Major perforation rate by disease from C3 to C7 was as follows: spine tumor (0/24, 0%), RA (2/59, 3.4%), DSA (3/65, 4.6%), CP (2/20, 10.0%), and CSM (6/40, 15.0%). There were no clinically important complications such as vertebra arterial injury, spinal cord injury, or nerve root injury caused by any screw perforation. Major perforation rate by vertebral level was: C2(2/30, 6.7%), C3(4/49, 8.2%), C4(6/43, 14.0%), C5(1/32, 3.1%), C6(1/41, 2.4%), and C7(1/45, 2.2%), showing highest rate for C4, followed by C3. Cervical pedicle screw perforation rate by disease was higher in CSM compared to RA and DSA. The perforation rate by vertebral level was higher for C4 and C3, in this order.

Bone alterations are associated with ankle osteoarthritis joint pain

Scientific Reports, 2016

The etiology of ankle osteoarthritis (OA) is largely unknown. We analyzed 24 ankle OA of 21 patie... more The etiology of ankle osteoarthritis (OA) is largely unknown. We analyzed 24 ankle OA of 21 patients diagnosed by plain radiographs using magnetic resonance imaging (MRI). Ankle joint pain disappeared in 22 out of 24 joints by conservative treatment. MRI bone signal changes in and around the ankle joints were observed in 22 of 24 joints. Bone signal changes along the joint line were seen in 10 of 11 joints as a Kellgren-Lawrence (KL) grade of II to IV. Such signal changes were witnessed in only 4 of 13 joints with KL grade 0 or I. In the talocrural joint, bone alterations occurred in both tibia and talus bones through the joint line in cases of KL grade III or IV, while focal bone alterations were present in the talus only in KL grade I or II cases. Sixteen of 24 joints exhibited intraosseous bone signal changes, which tended to correspond to joint pain of any ankle OA stage. Our results suggest that bone alterations around the ankle joint might be one of the etiologies of OA and associated with ankle joint pain.

Clinical Implications of Hip Flexion in the Measurement of Spinal Bone Mineral Density

Journal of Clinical Densitometry, 2016

The aim of this study was to investigate if differences in leg positioning affect spinal bone min... more The aim of this study was to investigate if differences in leg positioning affect spinal bone mineral density (BMD) measurements and the detection of low bone mass. Subjects included 1039 Japanese patients, 878 women and 161 men (mean ages: 67 and 71 years, respectively). Spinal BMD (L1-4) was measured using dual-energy X-ray absorptiometry (DXA) with patients lying in 2 different positions: (1) supine on the scanning table with hips flexed and knees flexed over a 90° support pad (the standard position) and (2) simply supine (the supine position). Predictive indices were calculated for spinal DXA acquired with patients in the supine position. A BMD T-score of -2.5 or lower was set as the threshold for low bone mass. For the standard and the supine positions during scanning in women, BMDs were 0.911 and 0.915 g/cm(2), respectively; in men, they were 1.117 and 1.124 g/cm(2), respectively. The estimated systematic bias in BMD between the positions was 0.42% (95% confidence interval: 0.24, 0.59; p = 0.009). Random errors in the densitometry measurements for the standard and supine positions were 0.66% and 0.84%, respectively. There was no significant difference between the errors (p= 0.164). The likelihood ratios of a positive and negative test for the detection of low bone mass following supine DXA were 121.0 and 0.066, respectively, compared with results acquired using the standard position. In conclusion, DXA measurements acquired with patients in the supine position slightly overestimated BMD vs the standard position. However, the clinical equivalency between the positioning methods for DXA is preserved to the extent that low bone mass can be reliably detected in the supine position.

$Research paper thumbnail of Risk factors of adjacent vertebral collapse after percutaneous vertebroplasty for osteoporotic vertebral fracture in postmenopausal women$

Risk factors of adjacent vertebral collapse after percutaneous vertebroplasty for osteoporotic vertebral fracture in postmenopausal women

BMC Musculoskeletal Disorders, 2016

Recently percutaneous vertebroplasty (PVP) was frequently performed for treatment of osteoporotic... more Recently percutaneous vertebroplasty (PVP) was frequently performed for treatment of osteoporotic vertebral fractures (VFs). It is widely accepted that new compression fractures tend to occur adjacent to the vertebral bodies, typically within a month after PVP. To determine the risk factors among several potential predictors for de novo VFs following PVP in patients with osteoporosis. We retrospectively screened the clinical results of 88 patients who had been treated by PVP. Fifteen cases were excluded due to non-union. Of the remaining 73 patients, 19 (26.0 %) later returned with pain due to a new vertebral compression fracture. One patient with a non-adjacent fracture and 2 patients with adjacent factures occurring 3 months later were excluded from the study. The 9 male patients were excluded to avoid gender bias. Ultimately, we divided the 61 remaining postmenopausal female patients (mean age: 78.9 years) into the collapse group (14 patients) who had experienced adjacent vertebral collapse after PVP and the non-collapse group (47 patients) who had not. Logistic regression analysis was performed to identify the risk factors for new VFs after PVP. All 14 cases of adjacent VF occurred within the first month after surgery. The collapse group had significantly advanced age, higher urinary N-terminal cross-linking telopeptide of type I collagen, and lower lumbar and hip bone mineral density (BMD) scores as compared with the non-collapse group. The odds ratios for age, lumbar, total hip, femoral neck, and trochanteric BMD were 4.5, 8.2, 4.5, 7.2, and 9.6, respectively. Positive likelihood ratios suggested that age more than 85 years, lumbar BMD less than 0.700 [-2.6SD], total hip BMD less than 0.700 [-1.8SD], neck BMD less than 0.600 [-2.1], and trochanter BMD less than 0.600 conferred an elevated risk of adjacent VF. Our study revealed that advanced age and decreased lumbar and hip BMD scores most strongly indicated a risk of adjacent VF following PVP.

Changes in serum vitamin D and PTH values using denosumab with or without bisphosphonate pre-treatment in osteoporotic patients: a short-term study

BMC endocrine disorders, Jan 15, 2015

Denosumab is a fully human monoclonal antibody that inhibits receptor activator of nuclear factor... more Denosumab is a fully human monoclonal antibody that inhibits receptor activator of nuclear factor kappa-β ligand (RANKL). Previous reports have shown that denosumab treatment of osteoporotic patients decreases bone resorption and fracture risk, but there have been no clinical studies on changes in bone turnover markers, 1,25(OH)2D3, or parathyroid hormone (PTH) in denosumab therapy with or without bisphosphonate (BP) pre-treatment in Japan. Here, we report such findings in 22 patients (11 in the denosumab alone group and 11 in the BP pre-treated group) with osteoporosis following 4 months of treatment. Bone metabolism had been inhibited by prior BP administration in the BP pre-treated group. The bone resorption markers serum tartrate-resistant acid phosphatase type 5b and urinary type I collagen cross-linked N-telopeptide were significantly decreased from baseline values for the entire study period in both groups. The bone formation marker bone alkaline phosphatase was significantly...

Bony findings detected by MRI may reflect the pathophysiology of osteoarthritis with thumb carpometacarpal joint pain

International journal of rheumatic diseases, Jan 18, 2015

Osteoarthritis (OA) is the most common skeletal disease worldwide. Although thumb carpametacarpal... more Osteoarthritis (OA) is the most common skeletal disease worldwide. Although thumb carpametacarpal joint (CMJ) OA is also frequently encountered, the etiologies remain largely unknown. We analyzed 20 patients who had thumb CMJ OA with accompanying joint pain and categorized a total of 37 thumbs according to the Eaton and Littler staging system. In patients with advanced OA, bone alterations as detected by magnetic resonance imaging (MRI) were observed in almost all of the painful joints. The frequency of bone alterations in the thumb CMJ increased with OA severity. In contrast, MRI revealed no bone alterations in thumbs with no pain and less pain in bilateral thumb basal pain, even in radiographically advanced OA. While the incidence of bone cysts in the CMJ was higher with OA staging, OA severity had no apparent correlation with pain. Thus, it is possible that the cause of thumb CMJ pain in advanced OA is bone alterations.

What Components Comprise the Measurement of the Tibial Tuberosity-Trochlear Groove Distance in a Patellar Dislocation Population?

The Journal of bone and joint surgery. American volume, Jan 2, 2015

The tibial tuberosity-trochlear groove distance is used as an indicator for medial tibial tubercl... more The tibial tuberosity-trochlear groove distance is used as an indicator for medial tibial tubercle transfer; however, to our knowledge, no studies have verified whether this distance is strongly affected by tubercle lateralization at the proximal part of the tibia. We hypothesized that the tibial tuberosity-trochlear groove distance is mainly affected by tibial tubercle lateralization at the proximal part of the tibia. Forty-four patients with a history of patellar dislocation and forty-four age and sex-matched controls were analyzed with use of computed tomography. The tibial tuberosity-trochlear groove distance, tibial tubercle lateralization, trochlear groove medialization, and knee rotation were measured and were compared between the patellar dislocation group and the control group. The association between the tibial tuberosity-trochlear groove distance and three other parameters was calculated with use of the Pearson correlation coefficient and partial correlation analysis. The...

Efficacy of Erythropoietin-Beta Injections During Autologous Blood Donation Before Spinal Deformity Surgery in Children and Teenagers

Spine, 2015

Retrospective observational study OBJECTIVE.: To clarify the efficacy of recombinant human erythr... more Retrospective observational study OBJECTIVE.: To clarify the efficacy of recombinant human erythropoietin-beta (EPO-beta) injections during autologous blood donation (ABD) before spinal deformity surgery in children and teenagers. ABD is preferred for spinal deformity surgery. A few studies have assessed the usefulness of preoperative ABD with EPO-beta in anemic patients. Fifty-six spinal deformity surgery patients (41 females, 15 males; median age: 15 yrs; range, 5-19 yrs) underwent preoperative ABD. ABD was performed weekly according to the patient's body weight with a subcutaneous EPO-beta injection (24,000 U). The collected blood volumes were compared among the low hemoglobin (low-Hb) (<13 g/dL), mid-Hb (13-13.9 g/dL), and high-Hb (≥14 g/dL) groups using the Kruskal-Wallis test. The effects of EPO-beta injection on the Hb levels were estimated using a linear mixed model. The patients underwent a median of four ABD collections (range, two to six). The median collected volu...

A case series of pregnancy- and lactation-associated osteoporosis and a review of the literature

by Hiroyuki Kato and Shota Ikegami

Therapeutics and clinical risk management, 2015

The syndrome of pregnancy- and lactation-associated osteoporosis is a rare disorder whose precise... more The syndrome of pregnancy- and lactation-associated osteoporosis is a rare disorder whose precise etiology and treatment are largely unknown. We herein report two such cases occurring in the early postpartum period that led to multiple fragility compression fractures. Combination therapy of vitamin D and vitamin K enabled a marked gradual increase in bone mineral density.

Osteoid osteoma presenting as thoracic scoliosis

by Hiroyuki Kato and Shota Ikegami

The spine journal : official journal of the North American Spine Society, Jan 2, 2015

Osteoid osteoma of the thoracic spine is relatively uncommon and is often difficult to diagnose, ... more Osteoid osteoma of the thoracic spine is relatively uncommon and is often difficult to diagnose, especially when patients do not complain of pain. To describe an unusual case of scoliosis due to osteoid osteoma of the thoracic spine that was challenging to diagnose. Case report of a 12-year-old girl who presented with scoliosis due to osteoid osteoma of the thoracic spine without apparent pain. Diagnosis of the lesion was made using computed tomography (CT) and Magnetic resonance imaging as well as the SRS-22 patient-based questionnaire. A preoperative CT myelogram revealed a mass lesion in the lamina of the 10(th) thoracic vertebra that was considered to be osteoid osteoma. This diagnosis was histologically confirmed following tumor excision. The patient's spinal deformity and SRS-22 scores were both improved at 5 months postoperatively. Osteoid osteoma of the thoracic spine may present as non-painful scoliosis. Tumor resection is effective. Clinicians should bear this uncommon...

Mini Open Foraminotomy for Cervical Radiculopathy: A Comparison of Large Tubular and TrimLine Retractors

by Hiroyuki Kato and Shota Ikegami

Asian spine journal, 2015

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Bone Alterations in Painful Osteoarthritic Shoulder

Journal of Case Reports, 2015

This report describes shoulder osteoarthritis due to bone alterations which were confirmed radiog... more This report describes shoulder osteoarthritis due to bone alterations which were confirmed radiographically. We report an 85 year old Japanese female with right shoulder pain. Radiographic findings showed bone signal changes using magnetic resonance imaging (MRI) and accumulation by bone scintigraphy in the affected area. The screening of other joint (left shoulder) showed no such changes. So, bone alterations may be involved in pathogenesis of shoulder osteoarthritis presenting with pain, which we want to emphasize in this case. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (creativecommons.org/licenses/by/3.0) Conflict of interest: None declared | Source of funding: Nil | DOI: http://dx.

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Osteoarthritis in the forefoot accompanied with joint pain is potentially associated with bone alterations

by Shota Ikegami and Hiroyuki Kato

International Journal of Diagnostic Imaging, 2015

The skeletal muscle cross sectional area in long-term bisphosphonate users is smaller than that of bone mineral density-matched controls with increased serum pentosidine concentrations

by Hiroyuki Kato and Shota Ikegami

Bone, Jan 21, 2015

Bisphosphonates are effective in increasing bone mineral density (BMD), but fragility fractures c... more Bisphosphonates are effective in increasing bone mineral density (BMD), but fragility fractures can still occur despite bisphosphonate treatment. The purpose of this study was to determine if long-term bisphosphonate users have characteristic findings in the musculoskeletal system, which could put them at risk of developing typical or atypical femoral fractures. We recruited 40 female patients who had taken bisphosphonates for more than 3years. The control group included 60 volunteers who were matched by age, body mass index, and dual-energy X-ray absorptiometry-derived BMDs. We measured the skeletal muscle cross sectional area around the proximal thigh and buckling ratio of the femoral neck using quantitative computed tomography (qCT) and several biochemical markers of bone metabolism. Those parameters were compared between the groups. While no significant differences of buckling ratio derived from qCT were detected, the skeletal muscle cross sectional area was significantly smalle...

Comparison of Spinous Process-Splitting Laminectomy versus Conventional Laminectomy for Lumbar Spinal Stenosis

by Hiroyuki Kato and Shota Ikegami

Asian spine journal, 2014

Seventy-five patients who had been treated for lumbar spinal stenosis (LSS) were reviewed retrosp... more Seventy-five patients who had been treated for lumbar spinal stenosis (LSS) were reviewed retrospectively. Invasion into the paravertebral muscle can cause major problems after laminectomy for LSS. To address these problems, we performed spinous process-splitting laminectomy. We present a comparative study of decompression of LSS using 2 approaches. There are no other study has investigated the lumbar spinal instability after spinous process-splitting laminectomy. This study included 75 patients who underwent laminectomy for the treatment of LSS and who were observed through follow-ups for more than 2 years. Fifty-five patients underwent spinous process-splitting laminectomy (splitting group) and 20 patients underwent conventional laminectomy (conventional group). We evaluated the clinical and radiographic results of each surgical procedure. Japanese Orthopaedic Association score improved significantly in both groups two years postoperatively. The following values were all significa...

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Mid-term results of computer-assisted cervical pedicle screw fixation

by Hiroyuki Kato and Shota Ikegami

Asian spine journal, 2014

A retrospective study. The present study aimed to evaluate mid-term results of cervical pedicle s... more A retrospective study. The present study aimed to evaluate mid-term results of cervical pedicle screw (CPS) fixation for cervical instability. CPS fixation has widely used in the treatment of cervical spinal instability from various causes; however, there are few reports on mid-term surgical results of CPS fixation. Record of 19 patients who underwent cervical and/or upper thoracic (C2-T1) pedicle screw fixation for cervical instability was reviewed. The mean observation period was 90.2 months. Evaluated items included Japanese Orthopaedic Association (JOA) score and C2-7 lordotic angle before surgery and at 5 years after surgery. Postoperative computerized tomography was used to determine the accuracy of screw placement. Visual analog scale (VAS) for neck pain and radiological evidence of adjacent segment degeneration (ASD) at the 5-year follow-up were also evaluated. Mean JOA score was significantly improved from 9.0 points before surgery to 12.8 at 5 years after surgery (p=0.001)...

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Elevation of serum alkaline phosphatase (ALP) level in postmenopausal women is caused by high bone turnover

by Hiroyuki Kato and Shota Ikegami

Aging clinical and experimental research, Jan 23, 2014

Most of the alkaline phosphatase (ALP) isoenzymes are derived from the bones and liver. High leve... more Most of the alkaline phosphatase (ALP) isoenzymes are derived from the bones and liver. High levels of ALP are often encountered during routine blood investigation in elderly patients. However, because ALP includes various isoenzymes from other tissues, an accurate diagnosis is usually not possible on the basis of elevated ALP alone. To identify the cause of increased ALP in postmenopausal women. We measured serum ALP in a group of 626 postmenopausal osteoporotic women before and after treatment with a bisphosphonate (either alendronate or risedronate). We analyzed the correlations between ALP levels and bone metabolic markers or hepatic function markers. The ALP and BAP levels of people in their 80s were significantly higher than those of people in their 60s. With bisphosphonate therapy, the BAP decreased, and the elevated ALP decreased to normal range levels. ALP was highly and significantly correlated with BAP both before and after treatment. The changes in levels of ALP correlat...

Mini Open Foraminotomy for Cervical Radiculopathy: A Comparison of Large Tubular and TrimLine Retractors

Asian spine journal, 2015

The Pathophysiology and Progression of Hip Osteoarthritis Accompanied with Joint Pain are Potentially Due to Bone Alterations - Follow-up Study of Hip OA Patients

The open rheumatology journal, 2014

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Skip pedicle screw fixation combined with Ponte osteotomy for adolescent idiopathic scoliosis

European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 2014

Perforation Rates of Cervical Pedicle Screw Insertion by Disease and Vertebral Level

The Spine Journal, 2010

Bone alterations are associated with ankle osteoarthritis joint pain

Scientific Reports, 2016

Clinical Implications of Hip Flexion in the Measurement of Spinal Bone Mineral Density

Journal of Clinical Densitometry, 2016

$Research paper thumbnail of Risk factors of adjacent vertebral collapse after percutaneous vertebroplasty for osteoporotic vertebral fracture in postmenopausal women$

Risk factors of adjacent vertebral collapse after percutaneous vertebroplasty for osteoporotic vertebral fracture in postmenopausal women

BMC Musculoskeletal Disorders, 2016