Spine Surgery and Related Research
Online ISSN : 2432-261X
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  • Makoto Takeuchi, Akihiro Nagamachi, Keisuke Adachi, Kazumasa Inoue, Ya ...
    Article ID: 2017-0071
    [Advance publication] Released: May 29, 2018
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    Introduction: A high-intensity zone (HIZ) in an intervertebral disc of the lumbar spine is a high-intensity signal located in the posterior annulus fibrosus on T2-weighted magnetic resonance imaging (MRI). There is limited information on the prevalence of HIZ in the lumbar spine according to age. The aim of this cross-sectional study was to investigate the prevalence of HIZ in the lumbar spine by age and the correlation between HIZ and other degenerative findings, such as disc degeneration, disc bulging and herniation, and changes in adjacent vertebral endplates on lumbar MRI.

    Methods and Methods: We retrospectively reviewed MRI studies of 305 patients (1525 discs) with low back pain, leg pain, or numbness. The prevalence of HIZ was calculated in 5 age groups (<20, 20–39, 40–59, 60–79, 80–91 years).

    Results: The number of patients in the 5 age groups was 19, 38, 69, 145, and 36, respectively. The prevalence of HIZ in the 5 age groups was 11.8%, 47.3%, 52.2%, 42.8%, and 50.0%, respectively. Disc degeneration was observed in 58.1% and 39.2% of discs with and without HIZ, respectively; disc bulging and herniation was observed in 63.9% and 41.1% and intensity changes at adjacent end plates in 11.6% and 10.0%, respectively.

    Conclusion: Prevalence of HIZ from the third decade of life onward was around 50%, with no significant change in prevalence beyond the age of 20 years. HIZ was correlated with disc degeneration, disc bulging, and disc herniation in patients with LBP, leg pain, or numbness.

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  • Koki Abe, Kazuhide Inage, Sumihisa Orita, Yoshihiro Sakuma, Hirohito K ...
    Article ID: 2017-0094
    [Advance publication] Released: May 29, 2018
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    Introduction: Thus far, few reports have described the time series histological variations in injured paravertebral muscle tissues for long durations, considering the type of pain.

    Purpose: To evaluate histological changes in injured paravertebral muscles and dominant nerves considering the type of pain.

    Methods: We used 59 eight-week-old male Sprague-Dawley rats. A 115-g weight was dropped from a height of 1 m on the right paravertebral muscle. Fluoro-Gold (FG), a sensory nerve tracer, was injected into this muscle. Hematoxylin and eosin (HE) staining and nerve growth factor (NGF) immunostaining of the muscle were performed for histological evaluation. L2 dorsal root ganglia (DRG) on both sides were resected, and immunohistochemical staining was performed for calcitonin gene-related peptide (CGRP, a pain-related neuropeptide) and for activating transcription factor 3 (ATF3, a neuron injury marker). Each examination was performed at 3 days, 1–3 weeks, and 6 weeks after injury.

    Results: HE staining of the paravertebral muscle indicated infiltration of inflammatory cells and the presence of granulation tissue in the injured part on the ipsilateral side at 3 days and 1 week after the injury. Fibroblasts and adipocytes were present at 2–3 weeks. At 6 weeks, the injured tissue was almost completely repaired. NGF was detected at 2–3 weeks post injury and appeared to colocalize with fibroblasts, but was not observed at 6 weeks post injury. The percentage of cells double-labeled with FG and CGRP in FG-positive cells of the primary muscle was significantly higher in the injured side at 3 days and 1–3 weeks post injury (P < 0.05). However, at 6 weeks, no significant difference was observed. No significant expression of ATF3 was observed.

    Conclusions: These results suggest that sensitization of the dominant nerve in the DRG, in which NGF may play an important role, can protract pain in injured muscles.

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  • Yoichiro Hatta, Hitoshi Tonomura, Masateru Nagae, Ryota Takatori, Yasu ...
    Article ID: 2017-0097
    [Advance publication] Released: May 29, 2018
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    Introduction. Favorable short-term outcomes have been reported following muscle-preserving interlaminar decompression (MILD), a less invasive decompression surgery for lumbar spinal canal stenosis (LSCS). However, there are no reports of mid- to long-term outcomes. The purpose of this study was to evaluate the clinical outcomes five or more years after treatment of LSCS with MILD.

    Methods. Subjects were 84 cases with LSCS (44 males; mean age, 68.7 years) examined five or more years after MILD. All patients had leg pain symptoms, with claudication and/or radicular pain. The patients were divided into three groups depending on the spinal deformity: 44 cases were without deformity (N group); 20 had degenerative spondylolisthesis (DS group); and 20 had degenerative scoliosis (DLS group). The clinical evaluation was performed using Japanese Orthopedic Association (JOA) scores, and revision surgeries were examined. Changes in lumbar alignment and stability were evaluated using plain radiographs.

    Results. The overall JOA score recovery rate was 65.5% at final follow-up. The recovery rate was 69.5% in the N group, 65.2% in the DS group, and 54.0% in the DLS group, with the rate of the DLS group being significantly lower. There were 16 revision surgery cases (19.0%): seven in the N group (15.9%), three in the DS group (15.0%) and six in the DLS group (30.0%). There were no significant differences between pre- and postoperative total lumbar alignment or dynamic intervertebral angle in any of the groups, slip percentage in the DS group, or Cobb angle in the DLS group.

    Conclusions. The mid-term clinical results of MILD were satisfactory, including in cases with deformity, and there was no major impact on radiologic lumbar alignment or stability. The clinical outcomes of cases with degenerative scoliosis were significantly less favorable and the revision rate was high. This should be taken into consideration when deciding on the surgical procedure.

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  • Masatoshi Morimoto, Toshinori Sakai, Tsuyoshi Goto, Kosuke Sugiura, Hi ...
    Article ID: 2017-0099
    [Advance publication] Released: May 29, 2018
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    Introduction: Recent advances in diagnostic imaging, such as computed tomography (CT) and magnetic resonance imaging (MRI), have allowed early diagnosis of lumbar spondylolysis (LS). However, few outpatient clinics are equipped with such imaging apparatuses and must rely on plain radiographs for the diagnosis of LS. The aim of this retrospective study was to identify how accurately fracture lines can be detected on plain radiographs in patients with LS.

    Methods: Patients with a diagnosis of LS were staged as early, progressive, or terminal. We evaluated whether fracture lines could be detected on plain radiographs and compared the detection rates under the following conditions: two directions including anteroposterior and lateral views (2 views), four directions including both oblique views (4 views), four directions including dynamic lateral views (4-D views), and all six directions (6 views).

    Results: In early LS, the fracture line detection rate was 11.4% using 2 views, 20.5% using 4 views and 4-D views, and 22.7% using 6 views. In progressive LS, the fracture line detection rate was 54.2% using 2 views, 70.8% using 4-D views, 75.0% using 4 views, and 79.2% using 6 views. The respective detection rates for terminal LS were 85.0%, 100%, 100%, and 100%.

    Conclusions: Although terminal LS was diagnosed accurately on plain radiographs in all patients, the detection rates were only 22.7% and 79.2% in patients with early and progressive LS, respectively. These results suggest that plain radiographic films can no longer be considered adequate for early and accurate diagnosis of LS. Advanced imaging procedures, such as MRI in the early diagnosis or CT for persistent cases, are recommended to obtain an accurate diagnosis of early stage LS in pediatric patients requiring conservative treatment to achieve bony healing.

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  • Laxmikant Dagdia, Terufumi Kokabu, Manabu Ito
    Article ID: 2017-0100
    [Advance publication] Released: May 29, 2018
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    Although adult spinal deformity (ASD) has become a global health problem, the classification system and optimal surgical treatment for ASD is yet to be standardized worldwide. A significant part of the population, as high as 10%, in industrialized societies will be aged above 65 years within the next 10 years. Herein, a systematic review of the scientific literature related to the classification and treatment of ASD was conducted wherein historical to the most recent classifications of ASD were reviewed. By discussing the benefits and limitations of the previous classification systems and considering the factors affecting the clinical outcomes of surgical treatment of ASD, this article would like to propose future directions for the development of a new classification system for ASD.

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  • Hirosuke Nishimura, Shinjiro Fukami, Kenji Endo, Hidekazu Suzuki, Yasu ...
    Article ID: 2018-0005
    [Advance publication] Released: May 29, 2018
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    This was a study of the case of a 60-year-old woman who presented with a six-month history of headache and numbness radiating to the right arm. MRI revealed a fusiform intramedullary spinal tumor spanning C2 to C5 at the hospital where she first presented. As her right upper limb weakness had presented gradually, she visited our hospital after one and a half years. Neurological examination revealed muscle weakness in the right deltoid, but no sensory disturbance.

    The patient underwent a C2-C6 total laminectomy and posterior midline myelotomy from the posterior median fissure of the spinal cord. The intraoperative histological diagnosis was glioma.

    Pathological findings in low magnification demonstrated clusters of small uniform nuclei embedded in a dense and fibrillary matrix in hematoxylin-eosin staining (H.E.). On immunohistochemical staining, the tumor cells were weakly positive for glial fibrillary acidic protein (GFAP), but negative for the epithelial membrane antigen (EMA). The histopathological findings were consistent with the diagnosis of a subependymoma. However, the MIB-1 labeling index was of moderately high level up to approximately 8%.

    In this case, we performed total resection because the tumor had rapidly increased in size and was of atypical form in histological findings.

    It should be minded that some of subependymomas have a possibility of rapidly increasing in size with progressing neurological deficits.

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  • Hiroaki Manabe, Toshinori Sakai, Fumitake Tezuka, Kazuta Yamashita, Yo ...
    Article ID: 2018-0015
    [Advance publication] Released: May 29, 2018
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    Introduction: C4 radiculopathy due to cervical spondylosis has rarely been reported as a cause of hemidiaphragmatic paralysis.

    Case Report: A 70-year-old man presented with hemidiaphragmatic paralysis due to right C3-C4 foraminal stenosis. The diagnosis was made preoperatively from findings on plain chest radiographs, respiratory function tests, and electrophysiologic tests. All the patient's test results and symptoms improved immediately after surgical treatment for cervical spondylosis.

    Conclusions: Although it may be difficult to make a correct diagnosis based only on radiological findings at the cervical spine, we should be aware of the existence of this entity and pay close attention to chest radiographs.

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  • Shigeru Hirabayashi, Tomoaki Kitagawa, Iwao Yamamoto, Kazuaki Yamada, ...
    Article ID: 2018-0016
    [Advance publication] Released: May 29, 2018
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    Postoperative C5 palsy (C5 palsy) is defined as de novo or aggravating muscle weakness mainly at the C5 region with slight or no sensory disturbance after cervical spine surgery. The features of C5 palsy are as follows: 1) one-half of patients are accompanied by sensory disturbance or intolerable pain at the C5 region; 2) 92% of patients have hemilateral palsy; 3) almost all palsy occurs within a week after surgery; 4) the incidence is almost the same between the anterior and posterior approaches to the cervical spine; 5) the prognosis is relatively good even in patients with severe muscle weakness. Even now, the precise causes of C5 palsy have not yet been revealed. From the viewpoint of the kinds of nerve tissue involved, the uncertain causes of C5 palsy are divided into two theories: 1) the segmental spinal cord disorder theory and 2) the nerve root injury theory. In the former, the segmental spinal cord, particularly the anterior horn cells, is thought to be chemically damaged because of preoperative ischemia and/or the aggression of reactive oxygen during postoperative reperfusion. By contrast, in the latter, the anterior rootlet and/or nerve root are believed to be mechanically damaged because of compression force and/or distraction force. In this theory, the features of C5 palsy can be well explained from anatomical viewpoints. Additionally, various countermeasures have been proposed, such as the intermittent relaxation of the tension of the hooks to the multifidus muscles during surgery; prophylactic foraminotomy to decompress C5 nerve root; prevention of excessive posterior shift of the spinal cord, which may cause the tethering effect of the nerve root; and prevention of excessive postoperative lordotic alignment of the cervical spine. These countermeasures have been proved effective, and may support the nerve root injury theory as the main conjectured theory on the causes of C5 palsy.

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  • Ryunosuke Fukushi, Satoshi Kawaguchi, Goichi Watanabe, Keiko Horigome, ...
    Article ID: 2018-0017
    [Advance publication] Released: May 29, 2018
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    Introduction: Vertebral fractures associated with ankylosing spinal disorders pose significant diagnostic and therapeutic challenges. Notably, the ankylosed spine remains in ankylosis after fracture treatment, and the underlying susceptibility to further fractures still remains. Nevertheless, information is scarce in the literature concerning patients with ankylosing spinal disorders who have multiple episodes of vertebral fractures.

    Case report: Case 1 involves an 83-year-old male patient with diffuse idiopathic skeletal hyperostosis (ankylosis from C2 to L4) who had three episodes of vertebral fractures. The first episode involved a C5–C6 extension-type fracture, which was treated with posterior segmental screw instrumentation. Five years later, the patient sustained a three-column fracture at the L1 vertebra following another fall. The fracture was managed with percutaneous segmental screw instrumentation. One year and two months postoperatively, the patient fell again and had a refracture of the healed L1 fracture. The patient was treated with a hard brace, and the fracture healed. Case 2 involves a 76-year-old female patient with ankylosing spondylitis (ankylosis from C7 to L2) who had two episodes. At the first episode, she suffered paraplegia due to a T8 vertebra fracture. The patient was treated with laminectomy and posterior segmental screw instrumentation. The patient recovered well and had all the hardware removed at 10 months postoperatively. Five years later, she had another fall and suffered a three-column fracture at L1. The patient underwent percutaneous segmental screw instrumentation. The patient required revision surgery with L1 laminectomy and L1 right pediclectomy for persistent right inguinal pain. At one-year follow-up, the patient recovered well, and the fracture healed.

    Conclusion: The abovementioned cases show that an age older than 75 years and a long spinal ankylosis from the cervical spine to the lumbar spine may serve as risk factors for the repetition of vertebral fractures associated with ankylosed spinal disorders.

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  • Norito Hayashi, Hideaki Iba, Kazuhiro Ohnaru, Kazuo Nakanishi, Toru Ha ...
    Article ID: 2017-0062
    [Advance publication] Released: April 27, 2018
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    Introduction. There are patients with lumbar disc herniation (LDH) having contralateral sciatic symptoms although the mechanisms of this clinical feature are still not well understood. The purpose of this study was to investigate these mechanisms by microendoscopic findings.

    Methods. Patients were performed microendoscopic surgery using over-the-top approach (ME-OTT), with laminoplasty, extirpation of herniation, and observation of the contralateral nerve root. The over-the-top approach was applied through the same incision from the herniation side. Clinical results were assessed according to the clinical scoring system established by the Japanese Orthopedic Association (JOA) score.

    Results. This study consisted of five patients, with the average age of 55.6 years old. The mean preoperative JOA score was 13 points. Three cases were Grade II and two were Grade III degrees of disc herniation. Levels of herniation were one at L3–4 and four at L4–5. Remission of sciatic symptoms was obtained in all cases after surgery. The average and percent improvements (%IP) of JOA scores at 2 months after surgery were 27.8 points and 92%, respectively. By the approach from the herniation side using ME-OTT, image around the contralateral nerve root was obtained without radical intervention. By ME-OTT, redness of the nerve root and fibrosis around the symptomatic nerve root were identified, whereas inflammatory changes were not apparent on the ipsilateral nerve root.

    Conclusions. Operative treatment of LDH with contralateral symptoms by ME-OTT was a useful procedure for decompression and observation of the affected nerve root. Asymptomatic disc herniation, "silent disc herniation," was considered at the herniation side since there were less inflammatory changes around the ipsilateral nerve root. In contrast, compression of dura toward the opposite side by disc herniation could have led to mechanical stress against the contralateral nerve root and triggered inflammation at lateral recess, resulting in radicular pain.

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  • Gaurav Raj Dhakal, Santosh Paudel, Siddharth Dhungana, Ganesh Gurung, ...
    Article ID: 2017-0087
    [Advance publication] Released: April 27, 2018
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    Background: Outcome of spine injury treated in resource constrained regions may not be the same as in developed nations. The aim of the present study was to study the epidemiological characteristics, delay, complications, and outcome of surgically treated dorsal and lumbar trauma.

    Methods: Retrospective study of dorsal and lumbar spine injury patients treated between December 2015 and August 2017. Patients were segregated into four groups based on the timing of surgery: 0 ̶ 2 days, 3 ̶ 7 days, 8 ̶ 30 days, and more than 31 days. Only one operating room twice a week was allotted to spine surgery, and spine had to compete with orthopedic and surgical trauma for admission and surgery.

    Results: Ninety-one patients (male 61) with mean age 33 years were operated for dorsal and lumbar spine injuries. 84% of the total patients sustained a fall, and 86.8% were from the periphery. Though 69.2% presented within 2 days, only 4.4% were operated within 2 days. Majority of the delay was due to unavailability of the operating room followed by financial constraints. Twenty-seven patients had complete deficit, 32 incomplete deficit, and 32 normal neurology. Four patients operated within 2 days improved their neurology, 7 incomplete deficit patients in 3 ̶ 7 days group improved, 6 in 8 ̶ 30 days group improved, whereas no patient in more than 31 days group improved. Overall 53.1% of neurologically incomplete deficit patients improved if operated within 30 days. No neurological improvement was seen in the 27 complete deficit patients. Wound infection, pulmonary contusion, and deep vein thrombosis were seen in 3 patients.

    Conclusion: As expected 95.6% of our patients were treated more than 3 days after injury and 60% more than a week later, which may not be acceptable in advanced countries. Despite the delay, 53.1% had an improvement in neurology when operated within 30 days. Hence, surgery still holds the hope of neurological recovery and quicker rehabilitation.

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  • Narihito Nagoshi, Ken Ishii, Kaori Kameyama, Osahiko Tsuji, Eijiro Oka ...
    Article ID: 2017-0088
    [Advance publication] Released: April 27, 2018
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    Introduction. Intramedullary lesions and tumors are generally accessed by a posterior approach. However, if the lesion is located on the ventral side of the spinal cord, a posterior resection with myelotomy poses technical difficulties. We report two cases of complete resection of a cervical ventral intramedullary cavernous hemangioma using an anterior approach.

    Case reports. Two cases of intramedullary cavernous hemangioma located on the ventral side of the spinal cord were successfully treated by total resection with anterior cervical corpectomy followed by anterior spinal fusion with an autologous bone strut from the iliac crest. In both cases, the postoperative course was uneventful, and there was no neurological deficit. Bony fusion was achieved, and there was no recurrence or complication during a follow-up period of at least two years.

    Conclusions. Here, we describe an anterior approach for total resection of cavernous hemangiomas on the ventral side of the cervical spinal cord. Outcomes were stable two years after the operations. Although the method should be assessed with more patients and a longer follow-up time, this anterior approach may be useful for the radical resection of a vascular malformation or tumor.

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  • Kazunari Takeuchi, Toru Yokoyama, Takuya Numasawa, Kan-ichiro Wada, Ta ...
    Article ID: 2017-0090
    [Advance publication] Released: April 27, 2018
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    Introduction. Difficulties with neck mobility often interfere with patients´ activities of daily living (ADL) after cervical posterior spine surgery. The range of motion of the cervical spine decreases markedly after multilevel cervical posterior decompression and fusion (PDF). However, details regarding the limitations of cervical spine function due to postoperative reduced neck mobility after multilevel PDF are as yet unclarified. The present study aimed to clarify the quality of life and its related factors after PDF, and the optimal fixed neck position in multilevel PDF that minimizes the limitations of ADL accompanying markedly reduced postoperative neck mobility.

    Methods. Limitations of ADL involving neck extension, rotation, and flexion were investigated in 32 consecutive patients who underwent C2-T1 PDF using the responses to the cervical spine function domain of the Japanese Orthopedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ). The EuroQol 5 Dimension, Japanese Orthopedic Association score, and five domains of the JOACMEQ were also investigated. We investigated the risk factors regarding the fixed neck position in PDF for the impossibility to perform ADL involving each of three movements using cut-off values obtained from receiver-operating characteristic curves.

    Results. Postoperative comprehensive quality of life was significantly related to neurological improvements and to poor outcomes of cervical spine function after PDF. The significant risk factors for impossibility to perform ADL involving neck rotation were a C2-C7 lordotic angle ≥ 6° (P = 0.0057) or a proportion coefficient of C2-T1 tilt angle/C2-C7 lordotic angle ≤ 1.8 (P = 0.0024). There were no significant risk factors for impossibility to perform ADL involving neck extension or flexion.

    Conclusions. The optimal fixed neck position in C2-T1 PDF to reduce postoperative limitations of ADL involving neck mobility is a C2-C7 lordotic angle of less than 6°, or a C2-T1 tilt angle (°) of greater than 1.8 × the C2-C7 lordotic angle (°).

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  • Shoichiro Takei, Masayuki Miyagi, Wataru Saito, Takayuki Imura, Gen In ...
    Article ID: 2017-0093
    [Advance publication] Released: April 27, 2018
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    Introduction: Patients with spinal muscular atrophy (SMA) usually have progressive scoliosis. Although fusion of the sacrum or pelvis has been recommended for correcting pelvic obliquity (PO), the procedure is invasive. This study determined as to whether performing instrumentation to the fifth lumbar vertebra (L5) is safe and effective for scoliosis in patients with SMA.

    Methods: Twelve patients with SMA underwent posterior spinal fusion and stopping instrumentation at the L5 level. We evaluated age at surgery, the duration of surgery, blood loss, complications, preoperative and postoperative Cobb angles, and PO.

    Results: The mean age at surgery was 11.4 years; the mean duration of surgery was 319 minutes, and the mean blood loss was 1170 mL. The Cobb angle improved from 97.3° to 39.1° at 1 month postoperatively (correction rate, 60.9%) and to 42.3° at the final follow-up. PO was corrected from 27.8° to 13.1° at 1 month postoperatively (correction rate, 51.7%) and to 19.8° at the final follow-up. No complications were reported. All patients showed improvement in low back pain, with reduced difficulty while sitting. However, >10% correction loss of PO was observed in 6 patients with high preoperative PO.

    Conclusions: The correction rate of scoliosis in SMA patients with posterior spinal fusion and instrumentation to the L5 level was acceptable, and no complications occurred. Scoliosis associated with SMA was more rigid and severer than scoliosis associated with Duchenne muscular dystrophy. Correction rates of the Cobb angle and PO in SMA patients with instrumentation to L5 were similar to those in SMA patients with instrumentation to the sacrum or pelvis. Correction loss of PO was greater in patients with high preoperative PO than in those with low preoperative PO. Instrumentation and fusion to L5 for scoliosis in patients with SMA seems safe and effective, except in cases of high preoperative PO.

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  • Ivan Sekiguchi, Naoki Takeda, Naoki Ishida
    Article ID: 2018-0002
    [Advance publication] Released: April 27, 2018
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    Introduction. In an attempt to increase anchoring strength of posterior instrumentation in spine with compromised bone quality, we introduced diagonal trajectory pedicle screwing (hooking screws) that do not rely on screw thread purchase in bone but rather hook onto the strong posterior elements of vertebrae from inside the bone.

    Methods. Between November 2016 and July 2017 we treated eight patients, mean age 80 years old (75–86 years old) with compromised bone quality for spinal instability. The diagnosis was osteoporotic fracture nonunion in three, ankylosed spine fracture in three, pyogenic spondylitis in two cases. All spines were percutaneously instrumented. Groove-entry technique was used for down-going thoracic screws. No additional hooks, cables, or any other augmentation was used. All patients were mobilized on post-operative day 1.

    Results. 84 screws were inserted overall. Groove-entry technique was used for 42 screws insertion. On average, 5.3 spinal segments were fixed per case. Mean operation time was 252 min (46 min per one spinal segment). Mean intraoperative bleeding was 112 ml per case (21 ml per one fixed spinal segment). All cases achieved bony union of the fracture site or across the destroyed intervertebral disk. Mean time to union was 4 months postop (3–7 months). All patients were ambulatory at the time of discharge. No nerve injury, no skin irritation caused by implants, no screw loosening, no screw pullout, no loss of correction, and no junctional kyphosis were noted in this series.

    Conclusion. Diagonal screw instrumentation (our hooking screws and groove-entry technique) appears to provide sufficient anchoring strength while being minimally invasive and possibly helpful in prevention of junctional kyphosis.

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  • Yoshihiro Matsumoto, Kenichi Kawaguchi, Jun-ichi Fukushi, Makoto Endo, ...
    Article ID: 2018-0004
    [Advance publication] Released: April 27, 2018
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    Purpose: To investigate the clinical outcome and prognostic factors of malignant spinal dumbbell tumors (m-SDTs).

    Methods: We retrospectively reviewed the clinical outcome of 22 consecutive cases of m-SDTs and analyzed the prognostic factors associated with worse outcome.

    Results: Nineteen of the 22 cases were managed with surgery (86%), and gross total resection (GTR) was achieved in four cases (21%). The duration of overall survival (OS) ranged from 3 to 140 months, with a median survival time of 15.3 months. The 5 year OS rate was 55.6%. In multivariate analysis, histological subtype (high-grade malignant peripheral nerve sheath tumor) (hazard ratio [HR] 14.9, p = 0.0191), GTR (HR 0.07, p = 0.0343), and presence of local recurrences (HR 11.2, p = 0.0479) were significant and independent predictors of OS.

    Conclusions: On the basis of clinical data, we propose that GTR and prevention of local recurrence may improve the clinical outcome of m-SDTs.

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  • Tatsuto Takeuchi, Keiichi Shigenobu
    Article ID: 2018-0010
    [Advance publication] Released: April 27, 2018
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    Introduction: Spinal subdural abscess (SSA) or empyema is a rare pathology and its exact incidence is unknown. Staphylococcus aureus (S aureus) is the most frequently responsible organism. The patients with SSA may have one or more predisposing immunosuppressive conditions. However, here we report a rare case of SSA following food intoxication without any significant comorbidities.

    Case report: A 42-year-old healthy man presenting with fever, severe low back pain (LBP), and trunk motion restriction was transferred to our hospital. He had been treated for an unknown fever after food intoxication in another hospital. Eighteen days earlier, he and his colleagues together ate raw horse meat and briefly boiled chicken breast. They all had food intoxication on the following day. Subsequently, our patient began to have a high fever and severe LBP. Laboratory data showed leukocytosis of 16,000/mm3. Also, the C-reactive protein was elevated to 26 mg/dL. The blood culture result was consistent with S aureus. Magnetic resonance imaging (MRI) showed focal epidural fluid collection that appeared contiguous with the subdural fluid collection through a dural defect in the axial plane on T2-weighted (T2W) images. An emergent surgery was performed. Frank pus was expressed from the epidural space as well as from the subdural space through the defect. The pus later grew S aureus. The patient was started on antibiotic therapy postoperatively. The patient completely recovered 1 month after surgery.

    Conclusion: SSA following food intoxication is a very rare case. SSA can be identified with a small dural defect and the intrathecal fluid collection compressing the cauda equina in the axial plane on T2W magnetic resonance images. Having suspicion of epidural abscess and likewise subdural abscess and making an early diagnosis using MRI and an emergent surgery are important when the clinician notices a febrile patient with severe LBP and trunk motion stiffness.

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  • Hiroyuki Takashima, Tsuneo Takebayashi, Mitsunori Yoshimoto, Maki Onod ...
    Article ID: 2017-0069
    [Advance publication] Released: April 07, 2018
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    Introduction: Gender differences may play a role in the pathogenesis of lumbar spinal stenosis. However, few reports that discuss the effects of gender differences in ligamentum flavum (LF) hypertrophy have been published, and no study has investigated the relationship between LF thickness and the quantitative value of intervertebral disc (IVD) degeneration. This study aimed to investigate the impact of gender on the pathomechanisms underlying LF hypertrophy, focusing on the relationship among LF thickness, IVD degeneration, and age.

    Methods: The subjects include 100 patients with low back pain and leg numbness, tingling, or pain. We measured LF thickness and the T2 values of IVDs using MR imaging and analyzed the relationship among LF thickness, T2 values of IVDs, and age. The interclass correlation coefficient (ICC) was calculated as the inter-rater reliability between the LF thickness values measured by two investigators.

    Results: ICC was calculated for the two measurements of LF thickness (r = 0.923, 95% CI: 0.907–0.936). No statistically significant difference in the T2 values of IVDs was observed between females and males from L2/3 to L5/S. There were significantly negative linear correlations between LF thickness and the T2 values of IVDs at all levels, but this correlation was not observed in females at L4/5. There were significantly negative linear correlations between age and the T2 values of IVDs from L2/3 to L5/S for all patients, females, and males (r = 0.422–0.756). In addition, there were significantly positive linear correlations between age and LF thickness from L2/3 to L4/5 for all patients (r = 0.329–0.361) and females (r = 0.411–0.481). Correlations were not observed for males at all levels or for all patients at L5/S.

    Conclusions: The relationships identified among LF thickness, age, and IVD degeneration suggest that gender differences play a role in the pathogenesis of LF hypertrophy.

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  • Mitsuyoshi Matsumoto, Masayuki Miyagi, Wataru Saito, Takayuki Imura, G ...
    Article ID: 2017-0075
    [Advance publication] Released: April 07, 2018
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    Purpose: Patients with neuromuscular disorders sometimes show progressive spinal scoliosis. The surgery for neuromuscular scoliosis (NMS) has high rates of complications. In this study, we elucidated the perioperative complications in patients with NMS.

    Methods: We included 83 patients with NMS (58 boys and 25 girls; 61 with muscular dystrophy, 18 with spinal muscular atrophy, and 4 others) who had undergone posterior fusion surgery for scoliosis. We evaluated the perioperative complications (within 3 months), age at time of surgery, operative time, blood loss, preoperative %VC and FEV1.0 (%) for pulmonary function, and preoperative ejection fraction (EF) for cardiac function.

    Results: There were 5 (6%) major complications, including pneumonia and a cardiovascular complication requiring intensive care unit (ICU) care, and 15 (18%) minor complications including viral enteritis and a urinary tract infection. Overall, there were 20 (24%) complications. Three of the 5 major complications were pulmonary. The mean age at the time of surgery was 13.7 y, operative time was 304 min, and blood loss was 1530 ml. The mean preoperative %VC was 41%, FEV1.0 was 91%, and EF was 60%. When we separated the patients into a group with major complications (n = 5) and a group without major complications (n = 78), the preoperative %VC in the group with major complications (23%) was significantly lower than that in the group without (42%) (p < 0.05). However, operative time, blood loss, preoperative FEV1.0 (%) and EF between the two groups were not significantly different (p > 0.05).

    Conclusion: Compared with the previous findings of the perioperative complication rate (45%–74%) for NMS, the complication rate was remarkably low in this case series. Because of advances in medical skills, including anesthesia and surgical instruments, surgery for NMS appears to be safe. However, patients with NMS with complications demonstrated severe restrictive ventilatory impairment preoperatively. Therefore, we should be vigilant for perioperative pulmonary complications especially in patients with NMS and preoperative severe restrictive ventilatory impairment.

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  • Tatsuya Yasuda, Tomohiko Hasegawa, Yu Yamato, Daisuke Togawa, Sho Koba ...
    Article ID: 2017-0081
    [Advance publication] Released: April 07, 2018
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    Object

    Correction of lumbar lordosis is the primary goal of surgical treatment of adult spinal deformity. However, only limited research has evaluated the effects of this correction on the adaptive curvature of the thoracic spine. The purpose of this study is to evaluate the change in thoracic curvature after corrective surgery to restore lumbar lordosis in patients with adult spinal deformity.

    Methods

    We completed a retrospective analysis of the radiological data of 65 patients, ≥50 years old, who underwent corrective surgery of lumbar spine lordosis from any level below T8 to the ilium. Patients with insufficient correction, defined by a pelvic incidence minus lumbar lordosis angle (PI-LL) > 10°, were excluded, with the data of 43 patients included in the analysis. The following radiological measures of spinal alignment were measured at three time points, preoperatively, on the first day of standing postoperatively and at 2 years post-surgery: sagittal vertical axis (SVA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), and PI-LL.

    Results

    Postoperative change in TK was correlated to preoperative TK and age. The increase in TK was larger for patients <75 years of age, increasing from 23.1° to 38.0° after surgery and to 46.7° at 2-years postoperatively. In contrast, for patients >75 years, TK remained largely unchanged at 37.8° just after surgery but increased substantively to 50.1° at the 2-year follow-up. The postoperative change in TK immediately after surgery was determined using equation "predict change in TK = −0.21 × age − 0.6 × preoperative TK + 41.8" by multiple regression analysis.

    Conclusion

    Reciprocal change in TK after lumbar spine correction is correlated to preoperative TK and age.

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  • Seiichi Odate, Jitsuhiko Shikata, Tsunemitsu Soeda
    Article ID: 2017-0084
    [Advance publication] Released: April 07, 2018
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    Introduction: Dropped head syndrome (DHS) after cervical laminoplasty (LAMP) is a rare complication, and no etiologies or surgical strategies have been reported. We present a patient who developed catastrophic DHS after LAMP despite having preoperative cervical lordosis that is known to be suitable for LAMP. We describe a hypothesis concerning the possible mechanism responsible for the DHS and a surgical strategy for relieving it.

    Case Report: A 76-year-old woman underwent LAMP for cervical spondylotic myelopathy. She achieved satisfactory improvement of neurological symptoms immediately after surgery. However, her neurological symptoms began to gradually deteriorate. She exhibited a dropped head and complained of difficulty maintaining horizontal gaze. Postoperative images showed a focal cervical kyphotic deformity causing anterior shift of the head, and recurrence of spinal cord compression was observed. She underwent additional surgeries for three times, but none of them restored her to baseline status. Retrospectively, the preoperative loading axis of the head existed anteriorly, and she also had a high T1 slope because of rigid thoracic kyphosis. Her preoperative hyper cervical lordosis was compensation for the global spinal malalignment. After LAMP, in accordance with decreases in her cervical lordosis, her head shifted anteriorly. The abnormal lever arm acting on the neck put further stress on the neck extensors, and the overstretched neck extensors possibly no longer generated enough power to raise the head. Uncompensated very high T1 slope because of marked thoracic kyphosis plus invasion of the posterior extensor mechanism by LAMP may have contributed to her catastrophic DHS development.

    Conclusions: In the treatment of cervical myelopathy, posterior decompression alone should be applied carefully to elderly patients with cervical sagittal imbalance even if they have apparent cervical lordosis. Once DHS occurs because of cervical sagittal imbalance, normalization of global spinal balance through corrective osteotomy may be indispensable for a successful outcome.

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  • Manabu Mukai, Masayuki Miyagi, Tomohisa Koyama, Takayuki Imura, Kuniak ...
    Article ID: 2017-0085
    [Advance publication] Released: April 07, 2018
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    Introduction: Spontaneous spinal epidural hematomas (SSEHs) are rare in childhood, especially in infants.

    Case report: We present the case of a 17-month-old-boy with trisomy 21 and a large SSEH. He was hospitalized for acute onset paraplegia after 6 days of irritability. Nine days after symptom onset, magnetic resonance imaging (MRI) of the spine revealed an extensive epidural hematoma between C7 and T5 causing severe spinal cord compression. After a coagulation disorder was ruled out (12 days after onset), he underwent emergency hemilaminectomy with evacuation of the hematoma. His neurologic impairment gradually improved, and 4 months after surgery he was back to his neurologic baseline. At 18 months after surgery, he was walking independently, although he had some developmental disabilities due to trisomy 21.

    Conclusion: Only 20 cases of SSEH in infancy have been previously reported, and this is the first report of SSEH in an infant with developmental disabilities. Because of the non-specific symptoms and difficulty obtaining MRIs in infants, particularly in those with developmental disabilities, the diagnosis and treatment of SSEH may be delayed. However, early diagnosis with MRI and early evacuation of SSEH in patients with severe neurological impairments is important for good outcomes. Attention must be paid to postoperative spinal deformity in infants.

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  • Sumihisa Orita, Miyako Suzuki, Kazuhide Inage, Yasuhiro Shiga, Kazuki ...
    Article ID: 2017-0086
    [Advance publication] Released: April 07, 2018
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    Introduction: Osteoporosis can produce a persistent state of pain known as osteoporotic pain. One proposed mechanism of this pathology is increased calcitonin gene-related peptide (CGRP; a marker related to inflammatory pain) expression in the dorsal root ganglia (DRG) innervating osteoporotic vertebrae. Alternatively, a previous study revealed that axial loading caused osteoporotic pain in a rodent model of coccygeal vertebrae compression. Because this compression model is associated with trauma, additional mechanistic studies of osteoporotic pain in the absence of trauma are required. The current study aimed to evaluate the expression and relative distribution of transient receptor potential vanilloid 4 (TRPV4), a pain-related mechanoreceptor, in ovariectomized (OVX) osteoporotic rats.

    Methods: CGRP-immunoreactive (-ir) and TRPV4-ir DRG neurons innervating the L3 vertebrae of Sprague-Dawley rats were labeled with a neurotracer, FluoroGold. Intravertebral pH was also measured during the neurotracer procedure. TRPV4-ir/CGRP-ir FluoroGold-positive DRG neurons were quantified in sham control and OVX rats (n = 10, ea). The threshold for statistical significance was set at P < 0.05.

    Results: There was no statistical difference in the number of FluoroGold-positive DRG neurons between groups; however, there were significantly more CGRP-ir/TRPV4-ir FluoroGold-positive DRG neurons in the OVX group compared with the sham control group (P < 0.05) as well as the significantly increased molecular production of each peptide. Intravertebral pH was also lower in the OVX group compared with the sham control group (P < 0.05).

    Conclusion: Sensory neurons innervating osteoporotic vertebrae exhibited increased expression of co-localized CGRP and TRPV4 in OVX osteoporotic rats. Additionally, intravertebral pH was low in the vicinity osteoporotic vertebrae. Considering that TRPV4 is a mechanosensitive nociceptor that is activated in acidic environments, its upregulation may be associated with the pathology of osteoporotic pain derived from microinflammation involved in osteoporosis.

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  • William Luo, Christina Cui, Sina Pourtaheri, Steven Garfin
    Article ID: 2017-0089
    [Advance publication] Released: April 07, 2018
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    Introduction. Vertebral compression fracture incidence is rising with the growth of the geriatric population and is one of the leading disabilities in healthcare. However, the literature is conflicted on the benefits of vertebral augmentation versus nonoperative care for these fractures. The purpose of the current study was to perform a review of all meta-analyses in the literature comparing vertebral augmentation to nonoperative care and descriptively report the results.

    Methods. A review of all meta-analyses evaluating trials of vertebral augmentation compared with nonoperative care was performed. The primary outcome studied was pain. Secondary outcomes were quality of life (QoL) metrics and functional outcomes.

    Results. Ten studies met the inclusion criteria. Besides two sham procedure studies, the remaining literature concluded that vertebral augmentation was superior to nonoperative care for reducing back pain. The reporting of secondary outcomes, such as QoL metrics and functional outcomes, was heterogeneous among the studies. Studies that reported these secondary outcomes, however, did identify some early benefit in vertebral augmentation.

    Conclusions. The current literature suggests vertebral augmentation is more effective in improving pain outcomes compared with nonoperative management. While more studies are needed to conclusively assess vertebral augmentation's efficacy in improving functional outcome and QoL, the meta-analyses surveyed here suggest that at least some benefit exists when assessing these two outcomes.

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  • Sean M. Rider, Shuichi Mizuno, James D. Kang
    Article ID: 2017-0095
    [Advance publication] Released: April 07, 2018
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    Intervertebral disc degeneration is a well-known cause of disability, the result of which includes neck and back pain with associated mobility limitations. The purpose of this article is to provide an overview of the known molecular mechanisms through which intervertebral disc degeneration occurs as a result of complex interactions of exogenous and endogenous stressors. This review will focus on some of the identified molecular changes leading to the deterioration of the extracellular matrix of both the annulus fibrosus and nucleus pulposus. In addition, we will provide a summation of our current knowledge supporting the role of associated DNA and intracellular damage, cellular senescence's catabolic effects, oxidative stress, and the cell's inappropriate response to damage in contributing to intervertebral disc degeneration. Our current understanding of the molecular mechanisms through which intervertebral disc degeneration occurs provides us with abundant insight into how physical and chemical changes exacerbate the degenerative process of the entire spine. Furthermore, we will describe some of the related molecular targets and therapies that may contribute to intervertebral repair and regeneration.

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  • Kotaro Satake, Tokumi Kanemura, Hiroaki Nakashima, Yoshimoto Ishikawa, ...
    Article ID: 2017-0096
    [Advance publication] Released: April 07, 2018
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    Purpose

    This retrospective study was performed to evaluate the clinical influence of - and to identify the risk factors for nonunion of transpsoas lateral lumbar interbody fusion (LLIF) with use of allograft.

    Methods

    Sixty-three patients who underwent transpsoas LLIF (69.8 ± 8.9 years, 21 males and 42 females, 125 segments) were followed for a minimum 2 years postoperatively. For all LLIF segments, polyetheretherketone (PEEK) cages packed with allogenic bone were applied with supplemental bilateral pedicle screws (PSs). Bone bridge formation was evaluated by computed tomography (CT) 2 years postoperative, and a segment without any bridge formation was determined to be a nonunion. Sixty-one participants (96.8%) were classified into two groups for clinical evacuation: Group N that contained one or more nonunion segments and Group F that contained no nonunion segment. Visual analogue scales (VAS) scores and the effective rates of the five domains of the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) were compared between Groups N and F. The risk factors for nonunion were determined by univariate and multivariate analyses.

    Results

    Twenty segments (16%) were diagnosed as nonunion. There were no significant differences in all VAS scores, and the ratio of effective cases in all domains of JOABPEQ between Group N (n = 14) and F (n = 47). Multivariate analysis identified percutaneous PS (PPS) usage (odds ratio [OR]: 3.14, 95% confidence interval: 1.13–8.68, p = 0.028) as a positive risk factor for nonunion.

    Conclusions

    We should be aware of the higher nonunion rate in the LLIF segments supplemented with PPS, though nonunion does not affect significantly clinical outcomes at 2 years postoperative.

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  • Katsuhito Yoshioka, Hideki Murakami, Satoru Demura, Satoshi Kato, Nori ...
    Article ID: 2017-0045
    [Advance publication] Released: March 15, 2018
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    Introduction: The majority of diffuse idiopathic skeletal hyperostosis (DISH) involving the anterior margin of the cervical vertebrae is asymptomatic, but it can cause dysphagia. Improvements in swallowing after surgical treatment have been reported in several case series. However, the appropriate amount of osteophyte resection for this disease in terms of the pathophysiology of dysphagia is still unknown. The current report describes the appropriate surgical procedure for dysphagia secondary to anterior cervical hyperostosis, and discusses the etiology of dysphagia.

    Methods: This is a retrospective review of four patients who presented with complaints of dysphagia secondary to anterior cervical hyperostosis. All patients underwent videofluoroscopic esophagrams (VFEs) to identify the specific region associated with the dysphagia. Esophageal obstruction was present at C3-4 in two patients and at C4-5 in two patients. Three patients underwent localized and limited resection of the anterior cervical osteophytes. One patient underwent total resection of the anterior cervical osteophytes, because re-ossification had occurred after a previous resection.

    Results: Postoperative VFE demonstrated an improvement in swallowing in the three patients who underwent limited resection of the osteophytes. The patient who underwent total resection of the osteophytes did not experience a full recovery of normal swallowing function. We concluded that the dysphagia was caused by both osteophyte obstruction and neuropathy resulting from the previous surgery or inflammation secondary to osteophyte irritation.

    Conclusions: Localized and limited resection of anterior cervical osteophytes is recommended and should be considered for patients with dysphagia from anterior cervical hyperostosis.

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  • Takashi Hirai, Toshitaka Yoshii, Hiroyuki Inose, Tsuyoshi Yamada, Masa ...
    Article ID: 2017-0048
    [Advance publication] Released: March 15, 2018
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    Introduction. Patients treated with revision surgery after lumbar decompression with fusion typically have persistent low back pain and lower extremity numbness compared with patients treated with only primary surgery. No well-designed study has investigated the persistence and degree of pain after revision surgery following instrumented operation. The purpose of this study is to compare residual pain among patients who underwent reoperation and those who underwent only primary surgery for lumbar degenerative disorder using patient-based evaluation.

    Methods. We reviewed 350 consecutive patients (143 men, 207 women, mean age 63 years) treated with primary lumbar instrumented surgery between October 2010 and February 2014 at our institution and followed up for ≥2 years postoperatively. Patients were categorized into three groups based on number of levels fused: 1-segment, 2-segment, and ≥3-segment fusion (1F, 2F, and ≥3F groups, respectively). We used the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and visual analog scales (VASs) for low back pain and lower extremity pain to evaluate pain intensity pre- and postoperatively.

    Results. Salvage surgery for late-phase complications was required in 5 cases (2.4%), 6 cases (11.3%), and 11 cases (12.1%) in the 1F, 2F, and ≥3F groups, respectively. In the 1F and 2F groups, patients treated with revision surgery had unsatisfactory improvement in the pain domain of JOABPEQ and VASs for low back pain and lower extremity pain compared with patients with only primary short fusion surgery. The ≥3F group showed no significant differences between patients who underwent reoperation and those who underwent only primary surgery.

    Conclusion. Low back pain and lower extremity pain often persist after revision surgery in patients treated with short fusion (≤2-segment) operation. We need to follow pain states in such patients.

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  • Costansia Bureta, Hiroyuki Tominaga, Takuya Yamamoto, Ichiro Kawamura, ...
    Article ID: 2017-0057
    [Advance publication] Released: March 15, 2018
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    Introduction: One complication after scoliosis surgery is ileus; however, few reports have described the frequency of and risk factors for this complication. We conducted a retrospective clinical study with logistic regression analysis to confirm the frequency of and risk factors for ileus after scoliosis surgery.

    Methods: After a retrospective review of data from patients who underwent surgical correction of spinal deformity from 2009 to 2014, 110 cases (age range, 4–73 yr; median, 14 yr) were included in the study. We defined postoperative ileus (POI) as a surgical complication characterized by decreased intestinal peristalsis and the absence of stool for more than 3 days postoperatively. Various parameters were compared between patients with POI and those without POI. Logistic regression analysis was performed to assess the risk factors associated with ileus; a P value of <0.05 was considered statistically significant.

    Results: Fifteen of 110 (13.6%) cases developed POI. The median height, weight, operation time, and blood loss volume of the patients with versus without POI were 146 versus 152 cm, 39.0 versus 44.0 kg, 387 versus 359 min, and 1590 versus 1170 g, respectively. There were no significant differences between patients with versus without POI in the measured parameters, with the exception of patient height, bed rest period, and presence of neuromuscular scoliosis. Multiple logistic regression analysis revealed neuromuscular scoliosis as a significant risk factor for POI (odds ratio, 4.21; 95% CI, 1.23–14.40).

    Conclusions: Our findings indicate a high probability of POI after scoliosis surgery, with an incidence of 13.6%. Neurogenic scoliosis, but not lowest instrumented vertebra or correction rate, was a risk factor for POI after scoliosis surgery. Digestive symptoms should be carefully monitored after surgery, particularly in patients with neuromuscular scoliosis.

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  • Kazuyuki Otani, Shigeo Shindo, Koichi Mizuno, Kazuo Kusano, Norihiko M ...
    Article ID: 2017-0059
    [Advance publication] Released: March 15, 2018
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    Introduction: Pedicle subtraction osteotomy (PSO) is performed to correct sagittal plane deformity. This procedure is useful with revision cases in which the number of intact discs for correction is limited.

    Methods: Forty-four patients (10 male and 34 female) with minimum follow-up of 2 years were reviewed; all had undergone PSO revision surgery for kyphosis following previous lumbar fusion surgery. The average age at operation was 72.8 years (range 42–85 years), and the average follow-up period was 4.1 years (2–9 years). The average fusion level was 7.5 (4–13 level), and the average previously fused level was 2.4 (1–7 level).

    Results: The average operation time was 424 min, and average blood loss was 2880g. The average JOA score of 14.0 before operation changed to 21.8 at 1-year follow-up and to 20.7 at final follow-up. The average recovery rate at final follow-up was 45.7%. Four patients underwent re-operations for proximal junctional kyphosis and 3 patients for rod fracture. The fusion rate was 88.6%, and 13 patients (29.5%) developed subsequent vertebral fracture. The average PI-LL (Pelvic incidence minus Lumbar lordosis) at pre-op of 52.9 degrees changed to 3.8 degrees at post-op, to 13.4 degrees at 1-year follow-up, and to 14.8 degrees at final follow-up. The average correction at the PSO site was 36.0 degrees at post-op, 36.7 degrees at 1-year follow-up, and 37.0 degrees at final follow-up. The average sagittal vertical axis at pre-op of 145.0 mm decreased to 51.2 mm at 1-year follow-up; however, it increased to 75.3 mm at final follow-up.

    Conclusion: PSO for correction of kyphosis following previous lumbar fusion surgery was an effective procedure without correction loss at the local osteotomy site; however, its surgical invasiveness and complication rate were high. Subsequent vertebral fracture, adjacent segment degeneration, and rod fracture contribute to deterioration of outcome that is evident at long-term follow-up.

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  • Satoshi Baba, Yoshihiro Matsumoto, Shinji Tomari, Takahiro Yasuhara, H ...
    Article ID: 2017-0068
    [Advance publication] Released: March 15, 2018
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    Introduction

    Several reports have demonstrated the surgical treatment strategy for patients with dialysis-associated spondylosis in the cervical spine (CDAS) with destructive spondyloarthropathy (DSA). However, studies focusing on the clinical outcome of patients with CDAS without DSA remain scarce. We aimed to review the treatment strategy of patients with CDAS but without DSA.

    Methods

    The clinical data and surgical records of consecutive patients with CDAS without DSA (n = 9; D-group) and cervical spondylotic myelopathy (CSM) (n = 30; C-group) who underwent modified double-door laminoplasty (DDL) were reviewed retrospectively. We investigated four radiologic factors in the pre-and postoperative periods that have been reported to be the risk factors for worsening of clinical symptoms in various studies and examined statistical comparison between the D and C groups.

    Results

    In the D group, the pre- versus postoperative C2–C7 sagittal angles were not significantly different, and only two patients (22%) had kyphosis postoperatively. There was a significant difference in the pre- and postoperative C2–C7 angles in the two groups (P = 0.031).

    Regarding the change in segmental alignment, the local open angle increased at the C4/C5 level in the D group. Also there was a significant difference in the local angles between the two groups at C4/5 and C5/6 (P = 0.00038, and 0.037), suggesting that postoperative segmental mobility at C4/5 and C5/6 was higher in the D group than in the C group.

    Conclusions

    In the present study, DDL in patients with CDAS without DSA did not adversely affect the postoperative alignment and stability compared with CSM patients with CSM. However, patients in the D group may have a chance to develop DSA change at the C4/5 level in the future, and careful long-term follow-up is warranted.

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  • Hidekazu Suzuki, Kenji Endo, Yasunobu Sawaji, Yuji Matsuoka, Hirosuke ...
    Article ID: 2017-0074
    [Advance publication] Released: March 15, 2018
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    Background

    Most people in modern societies spend the majority of their time sitting. However, sagittal spinal alignment is usually analyzed in the standing position. For understanding the symptoms associated with postural changes, this alignment is better to be analyzed in various positions. The purpose of this study was to investigate lumbo-pelvic relationships between standing up and sitting (sit-to-stand) motion.

    Methods

    The study subjects were 25 healthy young adult volunteers without any spinal symptoms. The following parameters were measured, namely, intervertebral range of motion (IV ROM), lumbar lordotic angle (L1L5), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI), on lateral whole-spine radiographs while sitting upright, sitting anterior flexed (anteflexed), standing anteflexed, and standing upright.

    Results

    The measurements of spinopelvic parameters during sit-to-stand motion (sitting upright, sitting anteflexed, standing anteflexed, standing upright, respectively) were as follows: L1L5 (7.9, −4.4, 3.1, 31.9) and PT (31.5, 26.5, 11.9, 7.7). Regarding IV ROM, the lumbar segmental ROM after seat-off was wider than before seat-off (sitting anteflexed). In particular, the L4-L5 segments had a wide ROM from standing anteflexed to standing upright.

    Conclusion

    The pelvis was retroverted in the sitting upright position and gradually anteverted during sit-to-stand motion. Lumbar lordosis decreased in the sitting upright position, temporarily decreased further (sitting anteflexed), and then increased in the standing position (standing anteflexed and standing upright). The mechanical loads on lumbosacral segments were greater after seat-off due to the reverse movement between upper lumbar and pelvic segments.

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  • Yuji Matsuoka, Kenji Endo, Hirosuke Nishimura, Hidekazu Suzuki, Yasuno ...
    Article ID: 2017-0078
    [Advance publication] Released: March 15, 2018
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    Background: Preoperative cervico-thoracic kyphosis and cervical regional positive imbalance are the risk factors for postoperative cervical kyphosis after expansive laminoplasty (ELAP). However, the relationship between preoperative global sagittal spinal alignment and postoperative cervical kyphosis in patients with cervical ossification of the posterior longitudinal ligament (OPLL) is unclear. The purpose of this study was to investigate the relationship between the onset of postoperative cervical kyphosis after ELAP and the preoperative global spinal sagittal alignment in patients with OPLL with normal sagittal spinal alignment.

    Methods: Sixty-nine consecutive patients without preoperative cervical kyphosis who underwent ELAP for OPLL and cervical spondylotic myelopathy (CSM) were enrolled. The global sagittal alignment radiography preoperatively and 1 year postoperatively were examined. The subjects were divided into a postoperative cervical lordosis group (LG) or a kyphosis group (KG) at 1 year postoperatively. The preoperative global sagittal spinal alignment between LG and KG in CSM and OPLL was compared.

    Results: The occurrence of cervical kyphosis after ELAP was 7 of 27 cases (25.9%) in OPLL and 13 of 42 cases (31.0%) in CSM. In patients with CSM in the KG, C7 the sagittal vertical axis (SVA) was smaller than in the LG. In patients with cervical OPLL in the KG, C2–C7 angle, C2–C7 SVA, and thoracic kyphosis (TK) were smaller than those in the LG. In OPLL, the age of the KG was younger than that of LG; however, this was not a significant difference in CSM.

    Conclusion: In patients with cervical OPLL without preoperative global spinal sagittal imbalance, preoperative small C2–C7 angle, C2–C7 SVA, TK, and younger age were typical characteristics of postoperative cervical kyphosis after ELAP.

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  • Keiji Nagata, Yuyu Ishimoto, Shinichi Nakao, Shoko Fujiwara, Toshiko M ...
    Article ID: 2017-0079
    [Advance publication] Released: March 15, 2018
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    Introduction: The aims of the present study were 1) to examine the association between neck and shoulder pain (NSP) and lifestyle in the general population and 2) to examine if sagittal spino-pelvic malalignment is more prevalent in NSP.

    Methods: A total of 107 volunteers (mean age, 64.5 years) were recruited in this study from listings of resident registrations in Kihoku region, Wakayama, Japan. Feeling pain or stiffness in the neck or shoulders was defined as an NSP. The items studied were: 1) the existence or lack of NSP and their severity (using VAS scale), 2) Short Form-36 (SF-36), 3) Self-Rating Questionnaire for Depression (SRQ-D), 4) Pain Catastrophizing Scale (PCS), 5) a detailed history consisting of 5 domains as being relevant to the psychosocial situation of patients with chronic pain, 6) A VAS of pain and numbness to the arm, and from thoracic region to legs. The radiographic parameters evaluated were also measured. Participants with a VAS score of 40 mm or higher and less were divided into 2 groups. Association of SF-36, SRQ-D, and PCS with NSP were assessed using multiple regression analysis.

    Results: In terms of QoL, psychological assessment and a detailed history, bodily pain in SF-36, SRQ-D, and family stress were significantly associated with NSP. A VAS of pain and numbness to the arm, and from thoracic region to legs, was significantly associated with NSP. There were no statistical correlations between the VAS and radiographic parameters of the cervical spine. Among the whole spine sagittal measurements, multiple logistic regression analysis showed that sacral slope (SS) and sagittal vertical axis (SVA) were significantly associated with NSP.

    Conclusion: In this study, we showed the factors associated with NSP. Large SS and reduced SVA were significantly associated with NSP, while cervical spine measurements were not.

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  • Shigeru Hirabayashi, Tomoaki Kitagawa, Iwao Yamamoto, Kazuaki Yamada, ...
    Article ID: 2017-0044
    [Advance publication] Released: February 28, 2018
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    Various methods via anterior or posterior approach with or without spinal stabilization have been performed in accordance with the level and configuration of ossification of the posterior longitudinal ligament (OPLL) as the decompression surgery for thoracic myelopathy due to OPLL. Among them, anterior decompression at the middle thoracic level (T4/T5-T7/T8) is especially difficult to perform because of the special anatomical structures, where the spinal alignment is kyphotic and the thoracic cage containing circulatory-respiratory organs exist nearby. Of the anterior decompression procedures at this level, the posterior approach has various advantages compared to the anterior one. In the anterior approach, the procedure is complicated and the effect of decompression of the spinal cord can be obtained only by direct resection or anterior floating of the OPLL. However, complications such as spinal cord injury and dural tear are most likely to occur at that time. On the contrary, in the posterior approach, the procedure is simple, and various options to obtain decompression can be selected from, these are, laminectomy, laminoplasty, dekyphosis surgery, staged decompression surgery (Tsuzuki's method), circumferential decompression via posterior approach alone (Ohtsuka's method), and circumferential decompression via combined posterior and anterior approaches (Tomita's method). Among them, in laminectomy, laminoplasty, and dekyphosis surgery, anterior decompression can be obtained to some extent without performing direct procedure on the OPLL. In Ohtsuka's method, complete decompression can be obtained via posterior approach alone, although it is somewhat technically demanding. It is preferable to drop the shaved down and separated OPLL anteriorly instead of trying to remove it completely to avoid complications, especially in patients with severe adhesion between the dura mater and OPLL.

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  • Kiyonori Yo, Eiki Tsushima, Yosuke Oishi, Masaaki Murase, Shoko Ota, Y ...
    Article ID: 2017-0060
    [Advance publication] Released: February 28, 2018
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    Introduction. Several measurement methods designed to provide an understanding of cervical sagittal alignment have been reported, but few studies have compared the reliabilities of these measurement methods. The purpose of the present study was to investigate the intraexaminer and interexaminer reliabilities of several cervical sagittal alignment measurement methods and of the rotated cervical spine using plain lateral cervical spine X-rays of patients with cervical spine disorders.

    Methods. Five different measurement methods (Borden's method; Ishihara index method (Ishihara method); C2-7 Cobb method (C2-7 Cobb); posterior tangent method: absolute rotation angle C2-7 (ARA); and classification of cervical spine alignment (CCSA)) were applied by seven examiners to plain lateral cervical spine X-rays of 20 patients (10 randomly extracted cases from a rotated cervical spine group and 10 from a nonrotated group) with cervical spine disorders. Case 1 and Case 2 intraclass correlation coefficients (ICCs) were used to analyze intraexaminer and interexaminer reliabilities. The necessary number of measurements and the necessary number of examiners were also determined. The target coefficient of correlation was set at ≥0.81 (almost perfect ICC).

    Results. In both groups, an ICC(1, 1) ≥ 0.81 was obtained with Borden's method, the Ishihara method, C2-7 Cobb, and ARA by all examiners. The necessary number of measurements was 1. With CCSA, a kappa coefficient of at least 0.9 was obtained. In both groups, with Borden's method, the Ishihara method, C2-7 Cobb, and ARA, the ICC(2, 1) was ≥0.9, indicating that the necessary number of examiners was 1. The standard error of measurement (SEM) was lowest with Borden's method, and the Ishihara method and C2-7 Cobb had almost the same values.

    Conclusions. Among cervical sagittal alignment measurement methods for cervical spine disorders, regardless of cervical spine rotation, Borden's method, Ishihara method, and C2-7 Cobb offer stronger reliability in terms of the ICC and SEM.

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