Publications by authors named "Satoshi Nori"

65 Publications

Can Postoperative Distal Adding-On be Predicted in Lenke Type 1B and 1C Curves with Intraoperative Radiographs?

Spine (Phila Pa 1976) 2021 Jul 16. Epub 2021 Jul 16.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan Department of Environmental and Occupational Health, School of Medicine, Toho University. Tokyo, Japan.

Study Design: A retrospective study of consecutive collected data.

Objective: To investigate risk factors for postoperative distal adding-on (DA) in Lenke Type 1B and 1C curves using intraoperative radiographs.

Summary Of Background Data: In adolescent idiopathic scoliosis (AIS), DA radiographic complication can negatively affect postoperative clinical results. However, few studies have focused on assessing risk factors for DA using intraoperative radiographs.

Methods: We retrospectively evaluated 69 AIS patients with Lenke Type 1B or 1C curves who underwent posterior selective thoracic fusion. We divided patients into DA and non-DA groups based on radiograph data at 2-year follow-up using Wang et al. (Spine 2011) definition of DA. We compared coronal radiographic parameters, including relative positions of end vertebra (EV), stable vertebra (SV), neutral vertebra (NV), and last touching vertebra (LTV) to lowest instrumented vertebra (LIV), and intraoperative radiographic parameters, between the two groups.

Results: DA was present in 13 patients (18.8%) at 2-year follow-up. The mean LIV-EV, LIV-NV, LIV-SV, and LIV-LTV relative positions were significantly smaller in the DA group than in the non-DA group. Multivariate analysis showed that LIV-LTV was significantly associated with DA (DA:-0.2 ± 0.7, non-DA: 0.6 ± 0.7). Intraoperative radiographs showed that the mean angulation of the first disc below the LIV after final adjustment was significantly larger in the DA group (2.3° ± 1.1°) than in the non-DA group (0.9° ± 0.7°). Patients whose angulation of the first disc below the LIV was more than 3° were significantly associated with DA.

Conclusion: The LIV selected at more cranial to the LTV may be a risk factor for postoperative DA in Lenke Type 1B and 1C curves. Moreover, it was suggested that LIV extension might be considered when the first disc's angulation below the LIV is > 3° in intraoperative radiographs.Level of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000004174DOI Listing
July 2021

Neurorehabilitation using a voluntary driven exoskeletal robot improves trunk function in patients with chronic spinal cord injury: a single-arm study.

Neural Regen Res 2022 Feb;17(2):427-432

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Body weight-supported treadmill training with the voluntary driven exoskeleton (VDE-BWSTT) has been shown to improve the gait function of patients with chronic spinal cord injury. However, little is known whether VDE-BWSTT can effectively improve the trunk function of patients with chronic spinal cord injury. In this open-label, single-arm study, nine patients with chronic spinal cord injury at the cervical or thoracic level (six males and three females, aged 37.8 ± 15.6 years, and time since injury 51.1 ± 31.8 months) who underwent outpatient VDE-BWSTT training program at Keio University Hospital, Japan from September 2017 to March 2019 were included. All patients underwent twenty 60-minute gait training sessions using VDE. Trunk muscular strength, i.e., the maximum force against which patient could maintain a sitting posture without any support, was evaluated in four directions: anterior, posterior, and lateral (right and left) after 10 and 20 training sessions. After intervention, lateral muscular strength significantly improved. In addition, a significant positive correlation was detected between the change in lateral trunk muscular strength after 20 training sessions relative to baseline and gait speed. The change in trunk muscular strength after 20 training sessions relative to baseline was greatly correlated with patient age. This suggests that older adult patients with chronic spinal cord injury achieved a greater improvement in trunk muscle strength following VDE-BWSTT. All these findings suggest that VDE-BWSTT can improve the trunk function of patients with chronic spinal cord injury and the effect might be greater in older adult patients. The study was approved by the Keio University of Medicine Ethics Committee (IRB No. 20150355-3) on September 26, 2017.
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http://dx.doi.org/10.4103/1673-5374.317983DOI Listing
February 2022

Upper End Vertebra of Proximal Thoracic Curve At T1 is a Novel Risk Factor of Postoperative Shoulder Imbalance in Lenke Type 2 Adolescent Idiopathic Scoliosis.

Global Spine J 2021 Jun 14:21925682211023049. Epub 2021 Jun 14.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Study Design: Retrospective single-center study.

Objective: We investigated the risk factors of postoperative shoulder imbalance (PSI) in patients with Lenke type 2 adolescent idiopathic scoliosis (AIS) including the position of preoperative upper end vertebra (UEV).

Methods: Seventy-five patients with Lenke type 2 AIS who underwent posterior correction and fusion surgeries from 2008 to 2018 were included. We included only patients whose upper instrumented vertebrae were at T2. The patients were divided into 2 groups based on radiographic shoulder height (RSH) at final follow-up, namely PSI group and non-PSI group, and PSI was defined as RSH > 10 mm. UEV, RSH, Cobb angle, curve flexibility, T1 and T2 tilt, correction rate, Risser grade, Scoliosis Research Society-22 scores, and demographic data were compared between the groups using independent tests or chi-square tests. Variables with value < 0.20 in univariate analysis were assessed in logistic regression analysis.

Results: Thirty-four patients in the PSI group and 37 patients in the non-PSI group were analyzed. Univariate analysis revealed that there were more patients with UEV at T1 (PSI: 85%, non-PSI: 54%, < 0.01) and Risser grade ≥ 3 (PSI: 88%, non-PSI: 62%; < 0.05) in the PSI group than in the non-PSI group. Logistic regression analysis revealed that UEV at T1 (odds ratio [OR] = 4.1 [1.2-14.4], < 0.05) and Risser grade ≥ 3 (OR = 3.9 [1.1-14.5], < 0.05) are significantly associated with PSI.

Conclusions: UEV at T1 and Risser grade ≥ 3 at the time of surgery are significant risk factors of PSI.
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http://dx.doi.org/10.1177/21925682211023049DOI Listing
June 2021

Spontaneous Reduction of Chiari Malformation and Syringomyelia After Posterior Spinal Fusion for Scoliosis: A Case Report.

JBJS Case Connect 2021 06 11;11(2). Epub 2021 Jun 11.

Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Case: A 22-year-old skeletally mature man with scoliosis accompanied by syringomyelia associated with Chiari malformation type 1 was presented to our hospital. Because the maximal syrinx/cord ratio was small, and he had no neurological deficit, he underwent corrective surgery without the treatment of the syringomyelia.

Conclusion: The scoliosis was corrected without any neurological complications. Magnetic resonance imaging taken 8 days after the surgery showed the reduction of the size of the syringomyelia. The syringomyelia almost disappeared at the 8-year follow-up.
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http://dx.doi.org/10.2106/JBJS.CC.20.00779DOI Listing
June 2021

Cervical intramedullary recurrent Ewing sarcoma after 10-year disease-free survival in an adult: a case report and review of literature.

Spinal Cord Ser Cases 2021 May 27;7(1):45. Epub 2021 May 27.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Introduction: Intramedullary metastasis of Ewing sarcoma is extremely rare. Here, we report an adult case of cervical intramedullary recurrent Ewing sarcoma after a 10-year disease-free survival after the initial surgery for a thoracic lesion.

Case Presentation: A 39-year-old man with a history of surgery and chemoradiotherapy for thoracic Ewing sarcoma ten years ago presented with neck pain and incomplete motor paralysis in the right upper extremity, which had suddenly appeared three months before. Cervical magnetic resonance imaging revealed a tear-drop-shaped intramedullary lesion at the C3 level accompanied by diffuse edematous change. Because of the rapid progression of his myelopathy, he underwent surgery for this intramedullary lesion. Intraoperatively, the tumor exhibited an orangish exophytic appearance. The unclearness of the tumor boundary compelled us to perform a partial resection. The histopathology showed the tumor comprised small round atypical cells with immunoreactivity for Nkx2.2 and CD99, diagnosing a metastatic Ewing sarcoma. Postoperatively, although his myelopathy improved transiently and adjuvant chemotherapy radiation was undergone, he died of cranial dissemination of the tumor two months and a half later.

Discussion: To our knowledge, 31 cases of primary and only 4 cases of recurrent intramedullary spinal Ewing sarcoma have been reported to date; however, this is the first case of recurrent intramedullary Ewing sarcoma with a 10-year disease-free survival. Sadly, the prognosis of the current case was extremely poor. There is no clear treatment guideline for recurrent intramedullary Ewing sarcoma because of its rarity, and further collection of similar cases would be required.
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http://dx.doi.org/10.1038/s41394-021-00406-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8160263PMC
May 2021

Coronal Plane Gap Increases Postoperative Pseudoarthrosis after Lateral Interbody Fusion for Adult Spinal Deformity.

Asian Spine J 2021 May 6. Epub 2021 May 6.

Department of Orthopaedic Surgery, Keio University School of Medicine, Shinjuku, Japan.

Study Design: This is a retrospective study.

Purpose: This study aims to evaluate the risk factor associated with pseudoarthrosis after placement of lateral interbody fusion (LIF) cages for adult spinal deformity (ASD) treatment.

Overview Of Literature: LIF technique is widely used for ASD correction. Furthermore, pseudoarthrosis is a major complication of fusion surgery required for revision surgery.

Methods: This study included 42 patients with ASD (two men and 40 women; 112 segments; mean, 68.5±8.4 years; and mean follow-up, 31.6±17.0 months) who underwent LIF and posterior correction surgery. The concave slot of the LIF cage was filled with an autologous iliac crest bone graft (IBG), and the convex slot with a porous hydroxyapatite/collagen (HAp/Col) composite was soaked with bone marrow aspirate. Endplate injury, the gap between vertebral endplate and cage in the coronal or sagittal plane, and fusion status were evaluated using computed tomography multiplanar reconstruction at 12 months after surgery. Moreover, the associated risk factors for pseudoarthrosis were analyzed.

Results: Fusion at LIF segments were observed in 71.4% segments at 12 months after surgery. Fusion on the concave slot (autologous IBG side), convex slot (porous HAp/Col composite side), and both concave and convex slots were observed in 66.1%, 37.5%, and 36.6% of patients, respectively. Moreover, pseudoarthrosis was observed in 28.6% at 12 months after surgery. Consequently, logistic regression analysis of the fusion at the LIF segment revealed that the gap between the LIF cage and endplate in the coronal plane (p=0.030; odds ratio, 0.183; 95% confidence interval, 0.030-0.183) was significantly associated with pseudoarthrosis at the LIF segments.

Conclusions: ASD surgery fusion rate using LIF cages was 71.4% at 12 months after surgery. The fusion rate was higher on the concave slot filled with autologous IBG than on the convex slot filled with a porous HAp/Col composite. The gap in the coronal plane was a risk factor for pseudoarthrosis at the LIF segment.
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http://dx.doi.org/10.31616/asj.2020.0336DOI Listing
May 2021

K-line (-) in the neck-flexed position negatively affects surgical outcome of expansive open-door laminoplasty for cervical spondylotic myelopathy.

J Orthop Sci 2021 Apr 14. Epub 2021 Apr 14.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan. Electronic address:

Background: The K-line in the neck-flexed position (FK-line) on radiography reflects dynamic factors and cervical alignment. Although the FK-line has been reported to affect the neurological recovery after muscle-preserving selective laminectomy for cervical spondylotic myelopathy (CSM), its influence on surgical outcomes after expansive open-door laminoplasty (ELAP) has not been investigated.

Methods: We reviewed the surgical outcomes in 81 patients with multilevel CSM who underwent C4-C6 ELAP combined with C3 and C7 partial laminectomy using a laminoplasty plate and were followed up for at least 2 years. We defined the K-line (-) as some portion of a bony spur or the vertebral body crossing the FK-line, whereas the FK-line (+) was defined as that never crossing the FK-line. Patients were divided into the FK-line (+) (n = 61) and FK-line (-) groups (n = 20), and the surgical outcomes were compared between the groups. A multivariate analysis was performed to identify the factors that influenced the neurological outcomes.

Results: The FK-line (-) group had a smaller C2-C7 angle, smaller C7 slope, greater postoperative increase in the C2-C7 sagittal vertical axis, greater kyphosis in cervical flexion and less lordosis in cervical extension, and higher incidence of postoperative residual spinal cord compression. The preoperative-to-postoperative changes in the Japanese Orthopedic Association (JOA) score and JOA score recovery rate (RR) were lower in the FK-line (-) group. The multiple linear regression analysis revealed that the K-line (-) (β = -0.327, P = 0.011) and high signal intensity (SI) changes on T2-weighted imaging (WI) combined with the low SI changes on T1-WI in the spinal cord (β = -0.320, P = 0.013) negatively affected the JOA score RR.

Conclusions: The FK-line can be used for patients with CSM as a simple indicator of neurological outcomes after ELAP.
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http://dx.doi.org/10.1016/j.jos.2021.02.005DOI Listing
April 2021

Surgical resection of arteriovenous fistula at the cauda equina.

Spinal Cord Ser Cases 2021 Apr 13;7(1):29. Epub 2021 Apr 13.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Introduction: Although spinal arteriovenous fistula (AVF) has been reported widely, AVF at the cauda equina is quite rare. We described a case of AVF at the cauda equina that was fed by the distal radicular artery (DRA).

Case Presentation: A 50-year-old woman presented with sudden weakness of the lower extremities. Magnetic resonance imaging (MRI) revealed a lesion with a highly intense signal at the conus medullaris, which was surrounded by several low-intensity signals (flow voids). Digital subtraction angiography revealed AVF at the cauda equina and that it was fed by the DRA, which was directly fed by the L3 segmental artery. We performed surgical resection of the AVF while monitoring motor-evoked potentials. The patient's postoperative course was uneventful, and her neurological symptoms gradually resolved. MRI 2 years after surgery showed the disappearance of both intramedullary edema and the flow voids.

Discussion: For the AVF, located at the cauda equina and fed by the DRA in this case, surgical resection or endovascular embolization could have been selected. We performed open surgery to achieve complete obliteration of the AVF, which led to postoperative functional recovery without any adverse events. However, only a limited number of AVFs at the level of the cauda equina have been reported, and treatment standards have not been established. Further studies of AVFs at the cauda equina are necessary to clarify the epidemiological characteristics and clinical outcomes with an appropriate sample size.
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http://dx.doi.org/10.1038/s41394-021-00400-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8044232PMC
April 2021

Gorham-Stout Disease Resulting in Spinal Deformity Treated by Fusion Surgery Combined With Everolimus Therapy: A Case Report.

JBJS Case Connect 2021 03 3;11(1). Epub 2021 Mar 3.

Department of Orthopedic Surgery, Keio University School of Medicine, Shinjuku, Tokyo, Japan.

Case: Gorham-Stout disease (GSD) is a rare disorder characterized by progressive localized osteolysis and lymphatic malformation. A 26-year-old woman with GSD presented to our hospital with a Cobb angle of 100° and a kyphosis angle of 88°. Everolimus therapy was initiated to control the disease prior to surgery. After halo-gravity traction for 4 weeks, we performed anterior and posterior spinal fusion. Postoperative computed tomography revealed satisfactory bone union and no significant loss of correction 1 year post-surgery.

Conclusion: This case suggests that anterior and posterior spinal fusion combined with everolimus therapy can be a therapeutic option for GSD.
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http://dx.doi.org/10.2106/JBJS.CC.20.00296DOI Listing
March 2021

Does Selective Posterior Correction and Fusion Surgery Influence Cervical Sagittal Alignment In Patient With Lenke Type 5 Adolescent Idiopathic Scoliosis? - A 5-Year Follow Up Retrospective Cohort Study.

Spine (Phila Pa 1976) 2021 Jan 25. Epub 2021 Jan 25.

Department of Orthopaedic Surgery, National Hospital Organization, Murayama Medical Center, Tokyo, Japan Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan Department of Orthopaedic Surgery, Fujita Health University, Aichi, Japan.

Study Design: A retrospective comparative study.

Objective: To examine the changes in cervical sagittal alignment (CSA) following surgical correction in a patient with Lenke type 5 adolescent idiopathic scoliosis (AIS) and evaluate any possible factors influencing postoperative CSA.

Summary Of Background Data: Few studies have assessed the association between CSA and thoracic or lumbar sagittal alignment in AIS patients with major thoracolumbar/lumbar curve who underwent posterior correction and fusion surgery.

Methods: 66 patients with Lenke type 5 AIS (2 males and 64 females, the mean age at surgery of 16.2 years) were included in this study. They were followed up for minimum 5 years after surgery. Multiple linear regression analysis was used to evaluate possible factors influencing the postoperative CSA. To determine the influence of upper end vertebra (UEV) level on postoperative CSA, the subjects were divided into two groups according to UEV level of ≥ T9 or ≤ T10. The outcome variables were compared between the two groups and analyzed for changes in various spinal sagittal profiles using radiographic outcomes.

Results: Multiple linear regression analysis revealed that preoperative T10-L2 kyphosis and LL were significantly correlated with postoperative C2-7 lordosis. However, CSA did not significantly change at 5 years after surgery. Sub-analysis of the cohort revealed that in the UEV ≥ T9 group, the mean thoracic kyphosis significantly increased from 20.3 ± 10.6° to 24.0 ± 8.9° and the mean C2-7 lordosis also significantly increased from -12.5 ± 8.3° to -4.3 ± 10.3° at 5-year postoperatively. SRS-22 outcomes were comparable between the groups.

Conclusion: We indicated that the CSA was not influenced by surgical correction in most Lenke type 5 AIS patients. However, in a patient whose UEV was located at T9 or higher levels, CSA was influenced through the changes in thoracic kyphosis following posterior correction surgery.Level of Evidence: 4.
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http://dx.doi.org/10.1097/BRS.0000000000003967DOI Listing
January 2021

How Pre-Operative Motor Weakness Affects the Extent of Recovery After Elective Spine Surgery in Patients with Degenerative Lumbar Spinal Stenosis.

Spine (Phila Pa 1976) 2021 Jan 25. Epub 2021 Jan 25.

Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo JAPAN.

Study Design: Retrospective review.

Objective: This study sought to determine how baseline motor weakness (MW) affects elective spine surgery in patients with degenerative lumbar spinal stenosis (LSS).

Summary Of Background Data: Favourable clinical outcomes have been described for elective spine surgery in patients with LSS. However, the way pre-operative MW affects the patient's health-related quality of life (HRQoL) after surgery is not well understood.

Methods: A retrospective review of prospectively collected data from 305 surgically treated patients with LSS who had 2-year follow-up was performed (age 71 ± 9 years, male 62%). Demographic, radiographic, and clinical outcomes were analysed at baseline and at 1-year, 2-year, and 3-year post-operation. the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) was used to assess the HRQoLs. The HRQoLs were compared between those with or without pre-op MW. Adjusted multivariate logistic regression analyses (MRAs) were performed to determine whether MW affected HRQoLs.

Results: 116 patients (38%) were categorized as MW+. The patient background including age, sex, presence of degenerative spondylolisthesis, type of surgery, and presence of neurological claudication, were similar between the 2 groups. However, the 1-, 2-, and 3-year post-operative VAS of back pain, leg pain, leg numbness, JOABPEQ lumbar function, social life, mental health, and walking ability were all inferior in the MW+ group, whereas a similar percentage of patients achieved a minimum clinically important difference in all subdomains at 3 years. The adjusted MRA showed that having ≥2 muscles with MW, and severity of MW (MMT grade) were independent risk factors for both difficulty climbing stairs and walking >15 minutes. (muscles with MW≥2; stair climbing: OR 6.4[2.3-17.4], walking: OR 3.2[1.4-7.3], severity of MW; stair climbing: OR 2.5[1.4-4.4], walking: OR 2.2[1.3-3.7]).

Conclusions: The patients with baseline MW had inferior HRQoL for up to 3 years compared to that of those without MW; however, the amount of improvement in HRQoL was comparable. Timely follow-up is important to find out the deterioration of motor function.Level of Evidence: 4.
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http://dx.doi.org/10.1097/BRS.0000000000003964DOI Listing
January 2021

Baseline severity of myelopathy predicts neurological outcomes after posterior decompression surgery for cervical spondylotic myelopathy: a retrospective study.

Spinal Cord 2021 May 25;59(5):547-553. Epub 2021 Jan 25.

Keio Spine Research Group (KSRG), Tokyo, Japan.

Study Design: Retrospective multicenter study.

Objectives: To identify the usefulness of the baseline severity of myelopathy for predicting surgical outcomes for cervical spondylotic myelopathy (CSM).

Setting: Seventeen institutions in Japan.

Methods: This study included 675 persons with CSM who underwent posterior decompression. According to baseline severity, the individuals were divided into the mild (Japanese Orthopaedic Association [JOA] score ≥ 14.5), moderate (JOA score = 10.5-14), and severe (JOA score ≤ 10) groups. Surgical outcomes and clinical variables were compared between the groups. Logistic regression analysis was used to develop a prediction model for unsatisfactory symptom state (postoperative JOA score ≤ 14, residual moderate or severe myelopathy).

Results: The mean (±standard deviation) age was 67 ± 12 years. The participants in the severe group were older than those in the mild group. Postoperative JOA scores were higher in the mild group than in the severe group. According to multivariate logistic regression analysis, the prediction model included preoperative JOA scores (odds ratio [OR] 0.60; 95% confidence interval [CI] 0.55-0.67) and age (OR 1.06, 95% CI 1.04-1.08). On the basis of the model, a representative combination of the thresholds to maximize the value of "sensitivity - (1 - specificity)" demonstrated a preoperative JOA score of 11.5 as a predictor of postoperative unsatisfactory symptom state in people around the mean age of the study cohort (67 years).

Conclusions: The combination of the baseline severity of myelopathy and age can predict postoperative symptom states after posterior decompression surgery for CSM.
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http://dx.doi.org/10.1038/s41393-020-00603-3DOI Listing
May 2021

Grade III intradural extramedullary anaplastic ependymoma managed with near-complete resection and adjuvant radiotherapy: a case report.

Spinal Cord Ser Cases 2021 Jan 19;7(1). Epub 2021 Jan 19.

Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.

Introduction: Of the 23 cases of spinal intradural-extramedullary ependymomas which have been reported to date, 11 were diagnosed as anaplastic. Here we present a very rare case of a thoracic intradural-extramedullary (not intramedullary) anaplastic ependymoma in an adult along with a literature review.

Case Presentation: A 29-year-old man presented with rapidly progressive gait disturbance, a sensory-deficit below the trunk and urination disorders that had begun a few months earlier. Magnetic resonance imaging of his thoracic spine revealed a dorsal-located intradural-extramedullary tumor at T4-5. The rapid deterioration of his symptoms within several months led him to refer to our department for surgery. Within one month the size of tumor increased to involve the T4-6 level, consequently worsening his gait disturbance. He underwent surgery and tumor mass was resected. However, there was leptomeningeal dissemination of the tumor cells on the surface of cord. A near-total resection was therefore achieved. Histopathology revealed the resected specimen had immunoreactivity for EMA/Vimentin/CD56/CD99/S-100/GFAP, with a Ki-67 index of ~35%. These factors led to the diagnosis of anaplastic ependymoma. Seven weeks postoperatively he received adjuvant radiotherapy to the whole brain and the whole spinal cord. He recovered as an independent ambulator without recurrence 1 year postoperatively.

Discussion: Because of their rarity, there are no clear treatment or adjuvant therapy guidelines for spinal anaplastic ependymoma. Adjuvant radiotherapy to the whole brain and spinal cord was necessarily indicated after near-total resection. Although the patient's condition has not recurred 1 year after surgery, careful and serial follow-up is necessary for this individual.
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http://dx.doi.org/10.1038/s41394-020-00367-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7815824PMC
January 2021

Characterization of Patients with Poor Risk for Clinical Outcomes in Adult Symptomatic Lumbar Deformity Surgery.

Spine (Phila Pa 1976) 2021 Jun;46(12):813-821

Department of Orthopedic Surgery, Keio University School of Medicine, Shinjuku City, Tokyo, Japan.

Study Design: Retrospective review of 159 surgically treated consecutive adult symptomatic lumbar deformity (ASLD) (65 ± 9 years, female: 94%) from a multicenter database.

Objective: The aim of this study was to provide a comprehensive analysis of the risk of a poor clinical outcome in ASLD surgery.

Summary Of Background Data: Poor-risk patients with ASLD remain poorly characterized.

Methods: ASLD was defined as age >40 years with a lumbar curve ≥30° or C7SVA ≥5 cm and Scoliosis Research Society 22 (SRS22) pain or function <4. Poor outcome was defined as 2y SRS22 total <4 or pain, function or satisfaction ≤3. The outcomes of interest included age, sex, body mass index, bone mineral density, Schwab-SRS type, frailty, history of arthroplasty, upper-instrumented vertebral, lower-instrumented vertebral, levels involved, pedicle subtraction osteotomy, lumbar interbody fusion, sagittal alignment, global alignment and proportion (GAP) score, baseline SRS22r score, estimated blood loss, time of surgery, and severe adverse event (SAE). Poisson regression analyses were performed to identify the independent risks for poor clinical outcome. A patient was considered at poor risk if the number of risks was >4.

Results: All SRS22 domains were significantly improved after surgery. In total, 21% (n = 34) reported satisfaction ≤3 and 29% (n = 46) reported pain or function ≤3. Poisson regression analysis revealed that frailty (odds ratio [OR]: 0.2 [0.1-0.8], P = .03), baseline mental-health (OR: 0.6 [0.4-0.9], P = .01) and function (OR: 1.9 [1.0-3.6], P < .01), GAP score (OR: 4.6 [1.1-18.7], P = .03), and SAE (OR: 3.0 [1.7-5.2], P < .01) were identified as independent risk for poor clinical outcome. Only 17% (n = 6) of the poor-risk patients reached SRS22 total score >4.0 at 2 years.

Conclusion: The overall clinical outcome was favorable for ASLD surgery. Poor-risk patients continue to have inferior outcomes, and alternative treatment strategies are needed to help improve outcomes in this patient population. Recognition and optimization of modifiable risk factors, such as physical function and mental health, and reduced SAEs may improve overall clinical outcomes of ASLD surgery.Level of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003927DOI Listing
June 2021

Residual lumbar curvature that developed during adolescence accelerates intervertebral disc degeneration in adulthood.

Spine Deform 2021 May 27;9(3):711-720. Epub 2020 Nov 27.

Department of Orthopaedic Surgery, Keio University School of Medicine, 35 Shinanomachi, Shinjyuku-ku, Tokyo, 160-8582, Japan.

Purpose: To elucidate the influence of spinal deformity in adolescent idiopathic scoliosis (AIS) on lumbar intervertebral disc (IVD) degeneration in adulthood using magnetic resonance imaging (MRI).

Methods: A total of 102 patients (8 men, 94 women; mean age, 31.4 years) who had developed idiopathic scoliosis at the age of 10-18 years and underwent preoperative lumbar spine MRI at the age of ≥ 20 were included in the study. Twenty volunteers (3 men, 17 women; mean age, 33.6 years) without scoliosis were assessed as controls. We divided the adult scoliosis patients into two groups: Group A consisted of patients with lumbar modifier A, and Group BC consisted of those with modifiers B and C. IVD degeneration from L1/2 to L5/S1 was assessed by MRI. The Scoliosis Research Society-22 (SRS-22) patient questionnaire was used in the patients' clinical assessment.

Results: There were 40 patients in the Group A and 62 in the Group BC. Compared to the control groups, significant IVD degeneration was observed at L2/3 and L3/4 in Group A, and at all levels except for L5/S1 in Group BC. The proportion of degenerated IVDs patients (Grades 1c and 2) was significantly higher in Group BC than those in Group A at L3/L4 and L4/L5. Furthermore, the severity of IVD degeneration was significantly greater in the group BC than in the group A at all levels, except for L5/S1, especially in patients aged > 30 years. The mean scores of all subdomains in the SRS-22 questionnaire were comparable between the two groups.

Conclusion: Our study showed that the residual lumbar curvature from AIS may have accelerated IVD degeneration in adulthood, especially in patients aged > 30 years.

Level Of Evidence: III.
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http://dx.doi.org/10.1007/s43390-020-00252-9DOI Listing
May 2021

Metabolic Syndrome is a Predisposing Factor for Diffuse Idiopathic Skeletal Hyperostosis.

Neurospine 2021 Mar 17;18(1):109-116. Epub 2020 Nov 17.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Objective: Diffuse idiopathic skeletal hyperostosis (DISH) causes spinal ankylosis, which can result in patients suffering specific spinal fractures that lead to a reduction in the activities of daily life in older patients. Currently, DISH is associated with diabetes mellitus and cardiovascular disease; however, the association between DISH and metabolic syndrome has not been established. The purpose of this study was to investigate a potential association between DISH and metabolic syndrome.

Methods: We retrospectively reviewed clinical data from consecutive subjects undergoing the musculoskeletal health medical checkups, and enrolled 327 subjects (174 men and 153 women; mean, 63.4 ± 13.7-years). Subjects who had spinal ankylosis at least 4 contiguous vertebral bodies were classified as the DISH group (n = 39) while the others were part of the non-DISH group (n = 288). The definition of the metabolic syndrome comes from diagnostic criteria used by the Japanese Society for Internal Medicine. Age, sex, body max index (BMI), hematological evaluation, blood pressure, presence of metabolic syndrome, the visceral fat area on abdominal computed tomography, and spinal epidural lipomatosis (SEL) on magnetic resonance imaging were evaluated.

Results: Compared to the non-DISH group, in the DISH group, mean age (DISH group, 74.3 years; non-DISH group, 1.9 years; p < 0.001), male prevalence were higher (DISH group, 82.1%; non-DISH group, 49.3%; p < 0.001), and BMI was greater (DISH group, 24.8; non-DISH group, 23.0; p = 0.006). the metabolic syndrome was more frequently observed in DISH group (28.9%) than in the non-DISH group (16.0%) (p = 0.045). The visceral fat area was significantly larger in the DISH group than in the non-DISH group (DISH group, 130.7 ± 58.2 cm2; Non-DISH group, 89.0 ± 48.1 cm2; p < 0.001). The prevalence of SEL was similar between the 2 groups (10.3% in the DISH group vs. 8.7% in the nonDISH group; p = 0.464). Poisson regression analysis revealed that the metabolic syndrome was significantly associated with DISH with odds ratio of 2.0 (95% confidence interval, 1.0-3.7; p = 0.004).

Conclusion: Metabolic syndrome was significantly associated with DISH. Our data showed metabolic syndrome is potentially related to DISH.
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http://dx.doi.org/10.14245/ns.2040350.175DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8021843PMC
March 2021

Effectiveness of Duloxetine for Postsurgical Chronic Neuropathic Disorders after Spine and Spinal Cord Surgery.

Asian Spine J 2020 Nov 16. Epub 2020 Nov 16.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Study Design: This is a retrospective observational study with an outpatient setting.

Purpose: This study aimed to describe the effects of duloxetine (DLX) administration for postsurgical chronic neuropathic disorders (both pain and numbness) following spinal surgery in patients without depression.

Overview Of Literature: Although several reports indicated the potential of DLX to effectively treat postoperative symptoms as a perioperative intervention, there have been no reports of its positive effect on postsurgical chronic neuropathic disorders.

Methods: A total of 24 patients with postsurgical chronic pain and/or numbness numeric rating scale (NRS) scores of ≥4 were enrolled. All patients underwent spine or spinal cord surgery at Keio University Hospital and received daily administration of DLX for more than 3 months. The mean postoperative period before the first administration of DLX was 35.5±57.0 months. DLX was administered for more than 3 months at a dose of 20, 40, or 60 mg/day, and the degree of pain and numbness was evaluated using the NRS before administration and 3 months after administration. Effectiveness was defined as more than a 2-point decrease in the NRS score following administration.

Results: In terms of the type of symptoms, 15 patients experienced only numbness, eight experienced both pain and numbness, and one experienced only pain. Of the 24 patients, 19 achieved effective relief with DLX. DLX was effective for all patients with postsurgical chronic pain (n=9), and it reduced postsurgical chronic numbness in 18 of 23 patients. No significant difference was observed in background spinal disorders. DLX was not effective for five patients who complained only of postsurgical chronic numbness.

Conclusions: This study reports the effectiveness of DLX for postsurgical chronic neuropathic disorders. Although DLX reduced postsurgical chronic pain (efficacy rate=100%) and numbness (78.3%) in certain patients, further investigation is needed to determine its optimal use.
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http://dx.doi.org/10.31616/asj.2020.0191DOI Listing
November 2020

Diabetes Does Not Adversely Affect Neurological Recovery and Reduction of Neck Pain After Posterior Decompression Surgery for Cervical Spondylotic Myelopathy: Results From a Retrospective Multicenter Study of 675 Patients.

Spine (Phila Pa 1976) 2021 Apr;46(7):433-439

Department of Orthopedic Surgery, National Hospital Organization Murayama Medical Center, Tokyo, Japan.

Study Design: Retrospective multicenter study.

Objective: The aim of this study was to identify the impact of diabetes on surgical outcomes of posterior decompression for cervical spondylotic myelopathy (CSM).

Summary Of Background Data: Although some previous studies have reported surgical outcomes of posterior decompression for CSM in diabetic patients, their results were inconsistent.

Methods: We included 675 patients with CSM who underwent posterior decompression. Patients were divided into diabetic (n = 140) and nondiabetic (n = 535) groups according to the diabetic criteria for glucose intolerance. Surgical outcomes as assessed by the Japanese Orthopedic Association (JOA) scores and visual analog scale (VAS) for neck pain were compared between groups. Subsequently, the functional outcomes of diabetic patients were compared between the mild (n = 131) and moderately severe (n = 9) groups. All patients were followed up for at least 1 year after surgery.

Results: Compared with the nondiabetic group, the diabetic group showed lower pre- and postoperative JOA scores (P = 0.025 and P = 0.001, respectively) and a lower JOA score recovery rate (RR) (P = 0.009). However, the preoperative-to-postoperative changes in JOA scores in the diabetic and nondiabetic groups were not significantly different (P = 0.988). Pre- and postoperative VAS for neck pain and postoperative reduction of neck pain were comparable between groups (P = 0.976, P = 0.913 and P = 0.688, respectively). Although statistical analysis was not performed due to the small underpowered sample size, functional outcomes assessed by the JOA score RR (43.3 ± 37.1% vs. 45.3 ± 33.9%) and preoperative-to-postoperative changes in JOA scores (3.0 ± 2.2 vs. 2.7 ± 2.5) were similar between the mild and moderately severe diabetes groups.

Conclusion: CSM patients with diabetes experienced improvements in neurological function and neck pain as a result of posterior decompression to the same extent seen in patients without diabetes.Level of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003817DOI Listing
April 2021

Chin on Chest Deformity Caused by Upper Cervical Kyphosis Associated With Ankylosing Spondylitis: A Case Report.

Neurospine 2020 09 30;17(3):666-671. Epub 2020 Sep 30.

Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Chin on chest deformity caused by upper cervical kyphosis associated with ankylosing spondylitis is rare. A 66-year-old woman presented at our institute with chief complaints of difficulty in horizontal gaze and opening her mouth. Cervical radiographs showed a C0-2 angle of 1° on flexion and 7° on extension, and her chin-brow vertical angle was 49°. We planned fixation surgery at C0-5 posteriorly to prevent the progression of kyphosis, with slight correction of the kyphosis at C0-2. The correction was performed by pushing down the over lordotically contoured titanium rods connected to an occipital plate onto the C3-5 lateral mass screws, just like cantilever technique. No palpable cracking or loss of resistance was noticed during the correction. However, intraoperative radiographs revealed apparent anterior separation of the vertebral bodies between C3 and C4. Postoperative computed tomography images at the C3/4 level suggested hemorrhage from the fracture site. Tracheostomy was performed because of massive edema around the pharynx. To secure solid bone fusion, staged surgery to extend the fusion to T3 and to graft an additional iliac bone was performed. Fortunately, the C2-7 angle was corrected to 40°, and her chin-brow vertical angle was restored to 17° without any catastrophic complications. Although the patient finally obtained an ideal sagittal alignment, the surgeon should be aware that the technique had a higher perioperative risk for iatrogenic fracture, resulting in neurological and vascular injuries.
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http://dx.doi.org/10.14245/ns.2040502.251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7538344PMC
September 2020

Limited Cost Benefit of Lateral Interbody Fusion for Adult Spinal Deformity Surgery.

Spine (Phila Pa 1976) 2021 Jan;46(1):48-53

Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo, Japan.

Study Design: Retrospective case series.

Objective: The aim of this study was to compare the utility and cost-effectiveness of multilevel lateral interbody fusion (LIF) combined with posterior spinal fusion (PSF) (L group) and conventional PSF (with transforaminal lumbar interbody fusion) (P group) in adult spinal deformity (ASD) surgery.

Summary Of Background Data: The clinical and radiographic outcomes of multilevel LIF for ASD have been reported favorable; however, the cost benefit of LIF in conjunction with PSF is still controversial.

Methods: Retrospective comparisons of 88 surgically treated ASD patients with minimum 2-year follow-up from a multicenter database (L group [n = 39] and P group [n = 49]) were performed. Demographic and radiographic data, health-related quality of life (HRQoL), and the direct hospitalization cost for the initial surgery and 2-year total hospitalization cost were analyzed.

Results: Analyses of sagittal spinal alignment showed no significant difference between the two groups at baseline and 2 years post-operation. Surgical time was longer in the L group (L vs. P: 354 vs. 268 minutes, P < 0.01), whereas the amount of blood loss was greater in the P group (494 vs. 678 mL, P = 0.03). The HRQoL was improved similarly at 2 years post-operation (L vs. P: SRS-22 total score, 3.86 vs. 3.80, P = 0.54), with comparable revision rates (L vs. P: 18% vs. 10%, P = 0.29). The total direct cost of index surgery was significantly higher in the L group (65,937 vs. 49,849 USD, P < 0.01), which was mainly due to the operating room cost, including implant cost (54,466 vs. 41,328 USD, P < 0.01). In addition, the 2-year total hospitalization cost, including revision surgery, was also significantly higher in the L group (70,847 vs. 52,560 USD, P < 0.01).

Conclusion: LIF with PSF is a similarly effective surgery for ASD when compared with conventional PSF. However, due to the significantly higher cost, additional studies on the cost-effectiveness of LIF in different ASD patient cohorts are warranted.

Level Of Evidence: 3.
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http://dx.doi.org/10.1097/BRS.0000000000003703DOI Listing
January 2021

A Rare Case of Proximal Junctional Failure with Delayed Infection after Adult Spinal Deformity Surgery: A Report of Two Cases.

Case Rep Orthop 2020 10;2020:8883828. Epub 2020 Jul 10.

Department of Orthopedic Surgery, Keio University School of Medicine, Japan.

Proximal junctional failure (PJF) is one of the most devastating complications that develop after adult spinal deformity (ASD) surgery. Here, we report 2 rare cases of PJF accompanied by delayed infection after ASD surgery with a review of the relevant literatures. Late-onset infection is an infrequent complication despite acute postoperative infection is common after posterior spinal instrumentation and fusion. Among them, delayed onset pyogenic spondylitis of the adjacent vertebra to the instrumented vertebrae is an extremely rare phenomenon. We do not have a clear explanation for this pathology. Since the delayed infections developed not in the fused segments but in the adjacent vertebra, the cause of the first case can be speculated as stimulation of low-virulent organisms to fester and hematogenous seeding and that of the second case as metal fretting and a sterile inflammatory response causing hematogenous microbial seeding, respectively. Additional studies on this phenomenon are warranted to elucidate the pathogenesis of this complication.
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http://dx.doi.org/10.1155/2020/8883828DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7369649PMC
July 2020

The effectiveness of chemonucleolysis with condoliase for treatment of painful lumbar disc herniation.

J Orthop Sci 2021 Jul 23;26(4):548-554. Epub 2020 Jul 23.

Department of Orthopaedic Surgery Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan. Electronic address:

Background: Chemonucleolysis with condoliase, which degrades chondroitin sulfate, could be a new, minimally invasive therapeutic option for patients with lumbar disc herniation (LDH). The purpose of this study was to analyze prognostic factors for clinical outcomes in LDH patients subjected to chemonucleolysis with condoliase.

Methods: Inclusion criteria for this procedure were 1) 18-70 years of age; 2) unilateral leg pain and positive straight leg raise (SLR) (<70°) or femoral nerve stretching test; 3) subligamentous extrusion verified on magnetic resonance imaging; 4) neurological symptoms consistent with a compressed nerve root on magnetic resonance imaging (MRI) images; and 5) minimum six months of follow-up. In total, 82 patients (55 men, 27 women; mean age, 47.2 ± 15.5 years; mean follow-up, 9.1 ± 3.0 months) who underwent chemonucleolysis with condoliase for painful LDH were included. An improvement of 50% or more in the Visual analogue scale (VAS) of leg pain was classified as effective.

Results: Seventy patients (85.4%) were classified into the effective (E) group and 12 patients (14.6%) into the less-effective (L) group. Surgical treatment was required in four patients. No severe adverse complications were reported; 41.3% of the patients developed disc degeneration of Pfirrmann grade 1 or more at the injected disc level. Univariate analysis revealed that young age (p = 0.036), without history of epidural or nerve root block (p = 0.024), and injection into the central portion of the intervertebral disc (p = 0.014) were significantly associated with clinical effectiveness. A logistic regression analysis revealed that injection into the central portion of the intervertebral disc (p = 0.049; odds ratio, 4.913; 95% confidence interval, 1.006-26.204) was significantly associated with clinical effectiveness.

Conclusions: Chemonucleolysis with condoliase is a safe and effective treatment for painful LDH; 85.4% of the patients showed improvement after the treatment without severe adverse events. To obtain the best outcome, condoliase should be injected into the center of the intervertebral disc.
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http://dx.doi.org/10.1016/j.jos.2020.06.004DOI Listing
July 2021

Concurrent dorsal subpial schwannoma and ventral meningioma arising at the same upper cervical level: a case report.

Spinal Cord Ser Cases 2020 07 15;6(1):64. Epub 2020 Jul 15.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Introduction: Multiple spinal cord tumors rarely occur without genetic predisposition, and concurrent tumors with discrete pathologies developed at the same spinal level are most rare. Here, we report a case of concurrent dorsal schwannoma and ventral meningioma arising at the same upper cervical level (C1-C2).

Case Presentation: A 55-year-old woman presented with neck pain and upper and lower extremity numbness for 1 year. Magnetic resonance imaging of the cervical spine showed a partially circumferential C-shaped intradural extramedullary tumor at C1-C2. The preoperative diagnosis based on imaging was intradural extramedullary meningioma with circumferential development. Surgical resection was performed, and dorsal subpial and ventral tumors were detected. Intraoperative pathological diagnosis was schwannoma for the dorsal tumor and meningioma for the ventral tumor. Both tumors were completely resected, followed by circumferential durotomy and duroplasty (Simpson grade 1 resection). Although symptoms related to cerebrospinal fluid hypovolemia occurred immediately after surgery, they disappeared within several days. At 2 years postoperatively, no local recurrence has been identified with mild kyphotic cervical malalignment.

Discussions: Only nine cases of concurrent multiple spinal tumors with discrete histopathological types at the same cervical level have been reported to date, however, this is the first case of meningioma combined with subpial schwannoma. Furthermore, although the ventral location of meningioma often compelled inadequate resection leaving behind a dura mater from which meningioma originated, a gross total resection including dura mater was achieved accompanied with circumferential duroplasty. Careful and sequential postoperative follow-up is ongoing for this individual.
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http://dx.doi.org/10.1038/s41394-020-0308-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7363873PMC
July 2020

Poor Prognostic Factors for Surgical Treatment of Spinal Intramedullary Ependymoma (World Health Organization Grade II).

Asian Spine J 2020 Dec 29;14(6):821-828. Epub 2020 May 29.

Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan.

Study Design: Single-center retrospective study.

Purpose: We aimed to explore the postoperative prognostic factors for spinal intramedullary ependymoma.

Overview Of Literature: Ependymoma (World Health Organization grade II) is the most frequent intramedullary spinal tumor and is treated by total resection. However, postoperative deterioration of motor function occasionally occurs.

Methods: Eighty patients who underwent surgical resection at Keio University and Fujita Health University in Tokyo, Japan between 2003 and 2015 with more than 2 years of follow-up were enrolled. A good surgical result was defined as an improvement in the modified McCormick Scale score by one grade or more or having the same clinical grade as was observed preoperatively. Meanwhile, a poor result was defined as a reduction in the McCormick Scale score of one grade or more or remaining in grade IV or V at final follow-up. Univariate and multivariate logistic regression analyses of the following factors were performed in the two groups: sex, age, preoperative Visual Analog Scale (VAS), tumor location, the extent of tumor resection, hemosiderin caps, cavity length, and tumor length on magnetic resonance imaging.

Results: At final follow-up, 15 patients were included in the poor results group and 65 in the good results group. In the univariate analysis, the factors related to poor results were as follows: higher age, preoperative McCormick Scale score severity, higher preoperative VAS, thoracic location, hemosiderin capped, and non-gross total resection (GTR). A multiple logistic regression analysis was conducted and showed that age, worse preoperative McCormick Scale score, and non-GTR were significant factors for poor prognosis.

Conclusions: The independent risk factors for motor deterioration after ependymoma resection were age, worse preoperative McCormick Scale score, and non-GTR. Early surgery for patients with even mild neurological disorders could facilitate functional outcomes. These results may contribute to determining the optimal timing of surgery for spinal intramedullary ependymoma.
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http://dx.doi.org/10.31616/asj.2020.0064DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7788358PMC
December 2020

Does K-line (-) in the Neck-flexed Position Predict Surgical Outcome of Cervical Spondylotic Myelopathy?: Results of a Multivariate Analysis After Muscle-preserving Selective Laminectomy.

Spine (Phila Pa 1976) 2020 Oct;45(19):E1225-E1231

Shiraishi Spine Clinic, Tokyo, Japan.

Study Design: A retrospective single-center study.

Objective: The aim of this study was to investigate the influence of the K-line in the neck-flexed position (flexion K-line) on the surgical outcome after muscle-preserving selective laminectomy (SL) for cervical spondylotic myelopathy (CSM).

Summary Of Background Data: Development of CSM is associated with dynamic factors and cervical alignment. The flexion K-line, which reflects both dynamic and alignment factors, provides an indicator of surgical outcome after posterior decompression surgery for patients with ossification of the posterior longitudinal ligament. However, the value of the flexion K-line for patients with CSM has not been evaluated.

Methods: Our study group included 159 patients treated with SL for CSM. Patients were divided into a flexion K-line (+) group and a flexion K-line (-) group. The influence of the flexion K-line on radiological and surgical outcomes was analyzed, with multivariate analysis conducted to identify factors affecting the surgical outcome.

Results: Patients in the flexion K-line (-) group were younger (P = 0.003), had a less lordotic cervical alignment (pre-and postoperatively, P < 0.001), a smaller C7 slope (pre-and postoperatively, P < 0.001), and a greater mismatch between the C7 slope and the C2-C7 angle (preoperatively, P = 0.047; postoperatively, P = 0.001). The postoperative increase in Japanese Orthopedic Association (JOA) score and the JOA score recovery rate (RR) were lower for the flexion K-line (-) than for the K-line (+) group (P < 0.001 and P < 0.001, respectively). On multivariate regression analysis, the flexion K-line (-) (β = -0.282, P < 0.001), high signal intensity (SI) changes on T2-weighted image (WI) combined with low SI changes on T1-WI in the spinal cord (β = -0.266, P < 0.001), and older age (β= -0.248, P = 0.001) were predictive of a lower JOA score RR.

Conclusion: The flexion K-line may be a useful predictor of surgical outcomes after SL in patients with CSM.

Level Of Evidence: 4.
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http://dx.doi.org/10.1097/BRS.0000000000003547DOI Listing
October 2020

Comparison between muscle-preserving selective laminectomy and laminoplasty for multilevel cervical spondylotic myelopathy.

Ann Transl Med 2020 Mar;8(5):160

Department of Orthopedic Surgery, Tokyo Dental College Ichikawa General Hospital, Chiba, Japan.

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http://dx.doi.org/10.21037/atm.2019.11.132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7154447PMC
March 2020
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