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Dive into the research topics where Yasuo Ito is active.

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Featured researches published by Yasuo Ito.


Spine | 2009

Does high dose methylprednisolone sodium succinate really improve neurological status in patient with acute cervical cord injury?: a prospective study about neurological recovery and early complications.

Yasuo Ito; Yoshihisa Sugimoto; Masao Tomioka; Nobuo Kai; Masato Tanaka

Study Design. Consecutive cohort study. Objective. To reconsider effects of the Second National Acute Spinal Cord Injury Study. Summary of Background Data. High dose methylprednisolone sodium succinate (MPSS) for the patients with acute spinal cord injury has been considered standard treatment in the several countries. However, many authors have criticized the effect of MPSS because of lack of evidence about neurologic improvement and the high incidence of complications. Methods. During 2-year, all patients with cervical cord injury were treated with MPSS within 8 hours of their injuries based on the Second National Acute Spinal Cord Injury Study protocol (MPSS group). During the next 2-year, all patients were treated without MPSS (non-MPSS group). There were 38 patients in the MPSS group and 41 in the non-MPSS. Early spinal decompression and stabilization was performed as soon after injury in both the groups. Results. According to The American Spinal Injury Association (ASIA) motor score, there was an average improvement by 3 months postinjury of 12.4 points in the MPSS group and 13.8 points in the non-MPSS group. In patients with complete motor loss, average ASIA motor score improved 9.0 points in the MPSS group and 12.6 points in the non-MPSS group. For patients with incomplete motor loss, average ASIA motor score improvement was 14.1 and 15.5 points in the MPSS and non-MPSS groups, respectively. In the MPSS group, 19 patients developed pneumonia, 13 developed urinary tract infections, and 5 developed wound infections. Incidence of pneumonia was significantly increased with the use of MPSS medication. Conclusion. We found no evidence supporting the opinion that high-dose MPSS administration facilitates neurologic improvement in patients with spinal cord injury. We believe MPSS should be used under limited circumstances because of the high incidence of pulmonary complication.


The Spine Journal | 2002

Pathogenesis and diagnosis of delayed vertebral collapse resulting from osteoporotic spinal fracture

Yasuo Ito; Yasuhiro Hasegawa; Kazukiyo Toda; Shinnosuke Nakahara

BACKGROUND CONTEXT In recent years there have been an increasing number of reports on surgical cases involving delayed neurological deficits caused by vertebral collapse after osteoporotic vertebral fracture. PURPOSE We do not yet know which patients are most susceptible to delayed vertebral collapse and subsequent neurological deficits, or whether this pathological condition can be prevented or predicted. In this study, we investigated the mechanism of progression and radiographic features characteristic of this disease, and we report here the predictive or risk factors for delayed osteoporotic vertebral collapse. STUDY DESIGN Retrospectively, we investigated the pathogenesis and diagnosis of delayed vertebral collapse with neurological deficit resulting from osteoporosis. PATIENT SAMPLE A total of 28 patients (7 men and 21 women) with neurological deficits resulting from vertebral collapse caused by osteoporotic vertebral fractures were the subjects for this study. OUTCOME MEASURES Comparisons and investigations about clinical features and radiographic findings between the patient group of delayed vertebral collapse with neurological deficits and the group of osteoporotic spinal fracture with no neurological deficits. METHODS The following factors were examined: the cause of injury; the length of time from injury, or the onset of pain, to the onset of neurological symptoms; radiographic findings obtained during the above period; the clinical course of vertebral fracture on plain X-ray films; time of appearance of the intravertebral cleft, and its localization and changes. RESULTS Six patients were hospitalized and prescribed a period of 2 weeks of bed rest followed by the fitting of a corset; seven outpatients were corseted but not prescribed bed rest; 15 patients were given medication only at an outpatient clinic. At radiography, intravertebral clefts were detected in 22 patients (79%) during the period from the appearance of pain to the onset of neurological deficit. In 14 patients (50%) who were radiographed every 1 to 2 weeks from the injury to the onset of neurological symptoms, the course of progression to collapse of the vertebral body could be observed. CONCLUSION Initial correct diagnosis and immobilization are important in preventing the delayed collapse with neurological deficit. The presence of an intravertebral cleft and instability of the affected vertebra represent risk factors for vertebral collapse with neurological deficit, requiring careful observation.


Spine | 2014

Multicenter Prospective Nonrandomized Controlled Clinical Trial to Prove Neurotherapeutic Effects of Granulocyte Colony-stimulating Factor for Acute Spinal Cord Injury: Analyses of Follow-up Cases After at Least 1 Year

Taigo Inada; Hiroshi Takahashi; Masashi Yamazaki; Akihiko Okawa; Tsuyoshi Sakuma; Kei Kato; Mitsuhiro Hashimoto; Koichi Hayashi; Takeo Furuya; Takayuki Fujiyoshi; Junko Kawabe; Chikato Mannoji; Tomohiro Miyashita; Ryo Kadota; Yukio Someya; Osamu Ikeda; Masayuki Hashimoto; Kota Suda; Tomomichi Kajino; Haruki Ueda; Yasuo Ito; Takayoshi Ueta; Hideki Hanaoka; Kazuhisa Takahashi; Masao Koda

Study Design. An open-labeled multicenter prospective nonrandomized controlled clinical trial. Objective. To confirm the feasibility of using granulocyte colony-stimulating factor (G-CSF) for treatment of acute spinal cord injury (SCI). Summary of Background Data. We previously reported that G-CSF promotes functional recovery after compression-induced SCI in mice. On the basis of these findings, we conducted a multicenter prospective controlled clinical trial to assess the feasibility of G-CSF therapy for patients with acute SCI. Methods. The trial ran from August 2009 to March 2011, and included 41 patients with SCI treated within 48 hours of onset. Informed consent was obtained from all patients. After providing consent, patients were divided into 2 groups. In the G-CSF group (17 patients), G-CSF (10 &mgr;g/kg/d) was intravenously administered for 5 consecutive days, and in the control group (24 patients), patients were similarly treated except for the G-CSF administration. We evaluated motor and sensory functions using the American Spinal Cord Injury Association score and American Spinal Cord Injury Association impairment scale at 1 week, 3 months, 6 months, and 1 year after onset. Results. Only 2 patients did not experience American Spinal Cord Injury Association impairment scale improvement in the G-CSF group. In contrast, 15 patients in the control group did not experience American Spinal Cord Injury Association impairment scale improvement. In the analysis of increased American Spinal Cord Injury Association motor score, a significant increase in G-CSF group was detected from 1 week after the administration compared with the control group. After that, some spontaneous increase of motor score was detected in control group, but the significant increase in G-CSF group was maintained until 1 year of follow-up. Conclusion. Despite the limitation that patient selection was not randomized, the present results suggest the possibility that G-CSF administration has beneficial effects on neurological recovery in patients with acute SCI. Level of Evidence: 3


Journal of Orthopaedic Science | 2009

Deep venous thrombosis in patients with acute cervical spinal cord injury in a Japanese population: assessment with Doppler ultrasonography

Yoshihisa Sugimoto; Yasuo Ito; Masao Tomioka; Masato Tanaka; Yasuhiro Hasegawa; Kie Nakago; Yukihisa Yagata

BackgroundDeep venous thrombosis (DVT) and pulmonary thromboembolism are major complications in patients with acute spinal cord injury. The incidence of DVT in patients with a spinal cord injury has ranged from 5% to 26% in several countries; however, the incidence in Japan is unknown.MethodsWe retrospectively assessed 52 patients with acute cervical spinal cord injury. According to the American Spinal Injury Association Impairment Scale (AIS) at admission, 17 patients were grade A, 15 grade B, 17 grade C, and 3 grade D.These patients were assessed for a DVT using color Doppler ultrasonography (US) regardless of whether they were symptomatic. As standard protocol, we perform Doppler US 5 days after injury; however, this retrospective research included patients who were assessed 2–13 days after injury.ResultsIn this study, 11 of 52 (21%) patients had DVT. Three patients had DVT of the right leg, six of the left leg, and two of bilateral legs. There were two proximal-type DVTs and nine distal-type DVTs. No patients had a symptomatic thrombopulmonary embolism. In all, 10 of 41 (24%) men had DVT and 1 of 11 (9%) women had DVT (P = 0.26). A total of 7 of 32 (22%) patients who had complete motor palsy (AIS A or B) had DVT, and 4 of 20 (20%) with incomplete motor palsy (AIS C or D) had DVT (P = 0.58). DVT was found 2–13 days after injury.ConclusionsIn this study of the Japanese population, 11 of 52 (21%) patients with acute cervical spinal cord injury had DVT. Several studies showed there were no differences in the incidence of DVT between patients with complete or incomplete palsy, and our study showed the same results. Many asymptomatic patients had DVT, so asymptomatic patients should not be neglected.


Spine | 2009

Cervical cord injury in patients with ankylosed spines: progressive paraplegia in two patients after posterior fusion without decompression.

Yoshihisa Sugimoto; Yasuo Ito; Masato Tanaka; Masao Tomioka; Yasuhiro Hasegawa; Kie Nakago; Yukihisa Yagata; Toshifumi Ozaki

Study Design. Case report and clinical discussion. Objective. To describe technical pitfall to treat 2 cervical cord injuries, including dislocations in patients with ankylosed spine due to diffuse idiopathic skeletal hyperostosis (DISH) or ossification of the posterior longitudinal ligament (OPLL). Summary of Background Data. DISH and OPLL are disease processes similar in pathology, which can lead to unexpected fractures due to low-energy trauma. In reported cases of fracture of the ankylosed spine in patients with DISH or OPLL, increasing lever arm and a grossly unstable fracture occurred. However, the actual surgical intervention for these fractures and spinal cord injuries was not discussed. Methods. We report 2 cervical cord injuries, including dislocations in patients with ankylosed spine due to DISH or OPLL. Results. Two patients underwent posterior fusion without decompression; however, postoperative progressive paraplegia still occurred. There were 3 points in common: these patients had ankylosed spines due to DISH or OPLL; they were elderly and had spinal canal stenosis; and after undergoing posterior fusion without decompression, their bilateral, lower extremity palsies worsened after surgery. Cervical alignment was slightly different after posterior fusion, and this change concentrated in one segment because adjacent vertebral bodies were ankylosed, and thus, immoveable. Additionally, this stress caused infolding of the ligamentum flavum with resultant spinal cord compression. Conclusion. In these cases, we recommend posterior fusion and decompression such as laminoplasty to avoid worsening palsy.


Spine | 2012

Biomechanical comparison of occiput-C1-C2 fixation techniques: C0-C1 transarticular screw and direct occiput condyle screw

Tomoyuki Takigawa; Peter Simon; Alejandro A. Espinoza Orías; Jae Taek Hong; Yasuo Ito; Nozomu Inoue; Howard S. An

Study Design. In vitro human cadaveric biomechanical study. Objective. The objective was to evaluate and compare the construct stability of occiput-C1–C2 fixation provided by C0–C1 transarticular screws or occipital condyle screws. Summary of Background Data. The placement of an occipital plate is commonly recommended in occipitocervical fixation surgery. However, there are unique clinical situations in which the placement of the occipital plate may not be possible or may have already failed. For these situations, 2 novel techniques that use the occipital condyle have been recently introduced: (1) C0–C1 transarticular screws fixation and (2) direct occipital condyle screws and C1 lateral mass screws fixation. However, there is a lack of thorough biomechanics studies of these techniques. Methods. Nondestructive kinematic tests and destructive tests were conducted in 16 fresh frozen cadaveric spines. As a nondestructive kinematic test, a pure moment of up to 2.0 N·m was applied in smooth continuous flexion/extension, lateral bending, and axial rotation motions. In addition to an intact-state case, a total of 5 different constructs (standard occipital plate, C0–C1 transarticular screws with/without occipital plate, and occipital condyle screws with/without occipital plate) were tested after destabilization of C0–C1 and C1–C2. All constructs had C2 pedicle screws fixation, and occipital condyle screws were incorporated with C1 lateral screws. Results. All fixation techniques significantly reduced ranges of motion compared with the intact state. In comparison with the standard occipital plate construct, the 2 novel techniques showed higher stability in axial rotation and lower stability in lateral bending. In both nondestructive and destructive tests, there were no statistical differences between C0–C1 transarticular screw construct and occipital condyle screw construct. Conclusion. The C0–C1 transarticular screw technique and direct occipital condyle screw with C1 lateral mass screw technique can be salvage fixation methods when occipital plate fixation is not feasible.


Archives of Orthopaedic and Trauma Surgery | 2009

Safety of atlantoaxial fusion using laminar and transarticular screws combined with an atlas hook in a patient with unilateral vertebral artery occlusion (case report)

Yoshihisa Sugimoto; Masato Tanaka; Kazuo Nakanishi; Haruo Misawa; Tomoyuki Takigawa; Yasuo Ito; Toshifumi Ozaki

Objective and importanceA disadvantage of transarticular and C2 pedicle screws is vertebral artery (VA) injury as a result of screw misplacement. If unilateral occlusion of the VA is present, VA injury of the dominant side will cause fatal complications as a result of collateral flow insufficiency. Several authors have recently reported the usefulness of C2 laminar screws because of their safety on VA injury. We used transarticular and C2 laminar screws combined with the atlas hook in a patient with C1-2 instability and unilateral VA occlusion, in order to reduce the risk of further VA injury.Clinical presentationA 64-year-old woman with rheumatoid atlantoaxial subluxation complained of cervical myelopathy and neck pain. Preoperative MR angiography showed a left side VA occlusion.TechniqueThe patient underwent atlantoaxial, posterior fusion using a transarticular screw on the side of the occlusion and a C2 laminar screw on the dominant side combined with a bilateral atlas hook. The transarticular screw was inserted using a navigation system and image intensifier, and the laminar screw was inserted free hand. Bone grafting from the iliac crest was performed.ConclusionTransarticular and C2 laminar screws fixation combined with the atlas hook in a patient with unilateral VA occlusion is a useful technique, in order to reduce the risk of further VA injury.


Spine | 2010

Risk Factors for Lumbosacral Plexus Palsy Related to Pelvic Fracture

Yoshihisa Sugimoto; Yasuo Ito; Masao Tomioka; Masato Tanaka; Yasuhiro Hasegawa; Kie Nakago; Yukihisa Yagata

Study Design. A retrospective study. Objective. We assessed risk factors for lumbosacral plexus palsy related to pelvic fracture that can be evaluated during the acute injury phase with diagnostics such as computed tomography (CT). Summary of Background Data. Many patients with pelvic fracture are in vital shock, with polytrauma and loss of consciousness, making an accurate neurologic examination very difficult in the emergency room. Methods. This study included 22 patients who had AO classification type B or C pelvic fractures. The 22 patients had 27 posterior osteoligamentary lesions. The average injury severity score (ISS) was 27.5 (range, 16–50). Age, sex, ISS, suicidal jump, longitudinal displacement, sacral transverse fracture, pubic fracture, lumbar transverse process fracture, type of pelvic fracture (AO), and type of sacral fracture (Denis) were examined for a correlation with the lumbosacral plexus palsy. Using coronal reconstruction CT, we considered a 10 mm or greater displacement at the sacrum or sacroiliac joint to be a longitudinal displacement. Transverse sacral fracture was diagnosed by sagittal reconstruction CT. Results. Of the 22 patients, 5 (22.7%) had lumbosacral plexus palsy (8 of 27 pelvic fractures) detected during treatment. The incidence of lumbosacral plexus palsy was not related to age, sex, ISS. Incidence of palsy was significantly higher when the patients affected side had longitudinal displacement. Patients who had made a suicidal jump or had a sacral transverse fracture also had a significantly higher risk for lumbosacral plexus palsy. Palsy was not related to the type of pelvic fracture (AO) or sacral fracture (Denis). Conclusion. In this study, longitudinal displacement of the pelvis, transverse sacral fracture, and trauma from a suicidal jump were risk factors for lumbosacral plexus palsy. These risk factors were helpful in our examination of patients who had severe pelvic fracture with loss of consciousness.


Acta Neurochirurgica | 2010

Vertebral rotation during pedicle screw insertion in patients with cervical injury

Yoshihisa Sugimoto; Yasuo Ito; Masao Tomioka; Tetsuya Shimokawa; Yasuyuki Shiozaki; Tetsuro Mazaki; Masato Tanaka

BackgroundCervical pedicle screws, when misplaced, tend to perforate laterally. One of the reasons for lateral perforation is vertebral rotation during screw insertion. However, actual vertebral rotation during pedicle screw insertion is unknown. In this study, we measured vertebral rotation during pedicle screw insertion in patients with cervical injury.MethodsWe inserted 76 pedicle screws into 38 vertebrae (C2 to C7) in 17 patients. All patients had some type of cervical injury. Screws were placed using intraoperative acquisition of data acquired with the isocentric C-arm fluoroscope (Iso-C3D) and computer navigation. We made screw holes using an image-guided awl, and we took images of cervical vertebrae in the neutral and rotational positions using navigation. Images of 76 insertions and rotational positions were taken while each cervical vertebra was under maximum stress at the time we were making the pedicle hole by awl.ResultsAverage cervical vertebra rotation was 10.6° (range 6 to 17) at C2, 9.1° (5 to 13) at C3, 7.8° (6 to 9) at C4, 6.7° (4 to 11) at C5, 4.9° (2 to 8) at C6, and 2.8° (0 to 4) at C7. Vertebrae in the upper and middle cervical spine rotated more than the lower cervical spine vertebrae. Of the 76 pedicle screws inserted into vertebrae between C2 and C7, 74 screws (97.4%) were classified as grade 1 (no pedicle perforation).ConclusionsIn this study, upper and middle cervical vertebrae in patients with neck injuries rotated more than the lower vertebrae. We should be especially careful of cervical rotation during screw insertion from C2 to C6, so as to prevent vertebral artery injury.


Journal of Spinal Disorders & Techniques | 2014

Minimally Invasive Spinopelvic Fixation for Unstable Bilateral Sacral Fractures.

Koichiro Koshimune; Yasuo Ito; Yoshihisa Sugimoto; Takeshi Kikuchi; Takuya Morita; Shoichiro Mizuno; Toshifumi Ozaki

Study Design:Retrospective case series. Objective:We present a minimally invasive spinopelvic fixation technique for unstable bilateral sacral fractures and describe a technical report. Summary of Background Data:Unstable sacral fractures are severe injuries with high mortality and morbidity due to pain and malunion. Galveston technique is useful for rigid fixation of an unstable sacral fracture. However, wound-related complications with this technique have been relatively common because of extensive contusion of the skin or poor blood supply after embolization. Materials and Methods:There were 34 patients with unstable pelvic fractures between 2005 and 2012. We performed conventional open surgery between 2005 and 2009. Minimally invasive spinopelvic fixation was performed between 2009 and 2012. Minimally invasive technique needs 4 small, lateral incisions for percutaneous lumbar pedicle screw insertion. We pushed a pure titanium rod into the paravertebral muscle. Results:The average surgical time was 345 minutes in the conventional fixation and 208 minutes with the minimally invasive fixation. The average intraoperative bleeding was 520 mL in the conventional fixation and 290 mL in minimally invasive fixation. When comparing deep wound infection, 3 of 8 (38%) patients who received conventional fixation had methicillin-resistant Staphylococcus aureus infections, whereas nobody who received the minimally invasive fixation acquired infection. Bony union was achieved in 15 of the 16 patients. Conclusions:In this study, minimally invasive spinopelvic fixation required a shorter surgical time, incurred less bleeding, and had a lower infection rate than fixation with the conventional Galveston technique.

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