Spine Surgery and Related Research
Online ISSN : 2432-261X
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  • Hiroyuki Takashima, Tsuneo Takebayashi, Mitsunori Yoshimoto, Maki Onod ...
    Article ID: 2017-0069
    [Advance publication] Released: April 07, 2018
    JOURNALS FREE ACCESS ADVANCE PUBLICATION

    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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  • Shigeru Hirabayashi
    Article ID: 2017-0061
    [Advance publication] Released: March 15, 2018
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    Introduction: Double-door laminoplasty (DDL) of the cervical spine (Kurokawa's method) was developed as one of posterior decompression surgical methods in the late 1970s and after then has been modified by adding various procedures such as the posterior muscle handling and the use of artificial spacers.

    There are three principles of DDL: First, to decompress the cervical spinal cord by central splitting of the spinous processes and laminae, preserving those lengths as much as possible and widening the spinal canal space symmetrically. Second, to maintain the widened spinal canal space steadily by fixing spacers made of hydroxyapatite the contour is almost the same as the widened space. Third, to re-suture the semispinalis muscles to the C2 spinous process to restore the strength of the posterior cervical muscles.

    Technical note: The important technical points in performing osteotomy are as follows: At each vertebra, osteotomy is performed from the caudal side and gradually proceeds to the cranial side because there is a space between the lamina and the dura mater at the caudal side and the osteotomy can be safely made. The surgeon must pay attention to the changes in color of the osteotomy site from red of cancellous bone, to white of the inner cortex, and finally to yellow of the yellow ligament and extradural fat tissue. Attention must be paid to the changes in sound and tactile sensation delivered from the air-drill when completing osteotomy of the inner cortex of lamina. By moving an air-drill slowly, tactile sensation can be more sensitive. During osteotomy, the process must be checked frequently by touching the inner cortex of the lamina with a probe.

    Conclusion: At present, DDL is a useful surgical method for cervical myelopathy at multiple level lesions.

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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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  • Grant D. Shifflett, Sravisht Iyer, Peter B. Derman, Philip K. Louie, H ...
    Article ID: 2017-0077
    [Advance publication] Released: March 15, 2018
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    Axial neck pain can frequently be a vexing clinical problem for practitioners. Cervical spine surgery is generally regarded as less successful for axial neck pain than arm complaints. Although only few case series exist in the literature, there is evidence to suggest that upper cervical radiculopathy could be an important, treatable source of axial neck pain. Unlike patients with axial neck pain, patients with radiculopathy usually present with unilateral pain, particularly in the trapezial, parascapular, mid clavicular, or even in the form of suboccipital headaches. Similar to other regions of the cervical spine, initial imaging often consists of plain radiographs of the cervical spine, with the use of magnetic resonance imaging (MRI) or computed tomography (CT) if further evaluation of the pathology is warranted. Selective injections and electromyography can be used in conjunction with the imaging studies to aid with proper diagnosis. The surgical management of upper cervical radiculopathy is reserved for patients who fail to improve with non-operative modalities. Anterior cervical discectomy and fusion (ACDF) remain the most commonly performed and most reliable procedure for the treatment of cervical radiculopathy. Wide decompression of disc material from uncinate to uncinate is performed with or without a foraminotomy on the symptomatic side to address anterior compressive pathology. Artificial disc replacement (ADR) has been recently introduced in hopes of maintaining motion at the pathologic levels. Young patients (<40 years old) with minimal facet joint arthrosis are best indicated for this surgery. Posterior cervical foraminotomy avoids many approach related complications associated with anterior surgery and is the preferred approach when anterior surgery is contraindicated. Very few studies with small sample sizes (likely due to underdiagnosis) make it difficult to perform a comparative analysis of the different types of procedures. Ultimately, an accurate diagnosis is likely the most important predictor of a positive surgical outcome.

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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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  • Yoshiharu Kawaguchi
    Article ID: 2017-0007
    [Advance publication] Released: February 28, 2018
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    This is a review paper on the topic of genetic background of degenerative disc diseases in the lumbar spine. Lumbar disc diseases (LDDs), such as lumbar disc degeneration and lumbar disc herniation, are the main cause of low back pain. There are a lot of studies that tried to identify the causes of LDDs. The causes have been categorized into environmental factors and genetic factors. Recent studies revealed that LDDs are mainly caused by genetic factors. Numerous studies have been carried out using the genetic approach for LDDs. The history of these studies is divided into three periods: (1) era of epidemiological research using familial background and twins, (2) era of genomic research using DNA polymorphisms to identify susceptible genes for LDDs, and (3) era of functional research to determine how the genes cause LDDs. This review article was undertaken to present the history of genetic approach to LDDs and to discuss the current issues and future perspectives.

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  • Ko Ishida, Yoichi Aota, Naoto Mitsugi, Takashi Kuniya, Takaaki Morii, ...
    Article ID: 2017-0011
    [Advance publication] Released: February 28, 2018
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    Purpose: To assess the bone fusion rates and clinical results of two surgical methods (pedicle screw claw-hook fixation and pedicle screw hook fixation) of lumbar spondylolysis repair.

    Methods: A multicenter database of surgical patients with lumbar spondylolysis was reviewed. All patients < 20 years old with a minimum of 6 months of follow-up and computed tomography images were included. Operation time and blood loss amount were investigated. Visual analogue scale (VAS; 0_10) scores for lower back pain were evaluated to assess clinical results.

    Results: A total of 17 patients met the inclusion criteria. Pedicle screw hook fixation was performed in five patients (the hook group), and pedicle screw claw-hook fixation was performed in 13 patients (the claw-hook group). One patient was included in both groups because each method was performed at different lumbar levels (L4 and L5). The bone fusion rates at 3, 6, and 9 months after surgery were significantly higher in the claw-hook group than those in the hook group. Operation time and blood loss amount were not significantly different between the groups. VAS scores improved in the claw-hook group but not in the hook group because of a small number of patients.

    Conclusions: Pedicle screw claw-hook fixation was more effective than pedicle screw hook fixation in terms of bone fusion rates.

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  • Kazuki Fujimoto, Kazuhide Inage, Toru Toyoguchi, Yawara Eguchi, Sumihi ...
    Article ID: 2017-0016
    [Advance publication] Released: February 28, 2018
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    Introduction

    Osteoporosis and sarcopenia are said to be similar disorders. However, few reports have described the effects of anti-osteoporosis drugs on muscle mass in clinical practice.

    Methods

    We selected 150 postmenopausal women with osteoporosis treated by minodronate (osteoporosis medication [OM] group) and 50 postmenopausal women without osteoporosis who did not receive treatment (no osteoporosis [NO] group). The OM group was further divided into two treatment subgroups: a combination of monthly minodronate and daily activated vitamin D vs. monthly minodronate alone. We measured lumbar spine and femoral neck bone mineral density (BMD) with dual-energy X-ray absorptiometry and muscle mass of the upper limbs, lower limbs, and trunk with bioelectrical impedance analysis at baseline and after 6 months.

    Results

    The OM and NO groups contained 130 and 37 patients, respectively (mean age: 73.9 ± 8.3 and 74.1 ± 10.0 years, respectively). In the OM group, lumbar spine BMD significantly increased after 6 months, while lower limb muscle mass significantly decreased. In the NO group, lumbar spine BMD and lower limb muscle mass did not significantly change after 6 months. In the OM group, BMD of the lumbar spine significantly increased but the lower limb muscle mass significantly decreased after 6 months relative to the NO group. In the combination therapy subgroup of the OM group muscle mass decreased significantly less than in the minodronate-alone subgroup.

    Conclusions

    In postmenopausal women with osteoporosis, minodronate can increase BMD but cannot increase muscle mass. However, simultaneous use of activated vitamin D can suppress muscle mass decrease. The combination of activated vitamin D and minodronate may be useful for treating osteoporosis in postmenopausal women.

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  • Shigeto Ebata, Tetsuro Ohba, Hirotaka Haro
    Article ID: 2017-0036
    [Advance publication] Released: February 28, 2018
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    Introduction: To comprehensively investigate the anatomy of the neuromuscular, visceral, vascular, and urinary tissues and their general influence on lateral lumbar interbody fusion (LLIF) surgery in the presence or absence of spinal deformity.

    Methods: We retrospectively reviewed 100 consecutive surgery cases for lumbar degenerative disease of patients aged on average 70.5 years and of which 67 were women. A sagittal vertical axis deviation of more than 50 mm was defined as adult spinal deformity (ASD: 50 patients). The degenerative disease of the other patients was defined as lumbar spinal stenosis (LSS: 50 patients). We analyzed the relative anatomical position of the psoas major muscle, lumbar plexus, femoral nerves, inferior vena cava, abdominal aorta and its bifurcation, ureter, testicular or ovarian artery, kidney and transverse abdominal muscle in patients with ASD or with LSS, using preoperative magnetic resonance imaging (MRI).

    Results: For patients with ASD, the L4-5 intervertebral disk was closer to the lumbar nerve plexus than it was in those with LSS (p < 0.0001), and a rising psoas sign at the L4-5 disk was significantly more frequent in patients with ASD than in those with LSS (p < 0.05). The aortic bifurcation frequently appeared at the level of L4-5 in patients with either degenerative disease, so the common iliac artery may pass near the disk. The inferior vena cava passed closer to the center of the L4-5 disk in patients with ASD than it did in those with LSS (p < 0.05). The transverse abdominal muscle at L2-3, L3-4, and L4-5 was closer to and less than 3 mm from the kidneys in many more patients with ASD than was the case for patients with LSS (p = 0.3, p < 0.05, p = 0.29, respectively).

    Conclusions: We recommend careful preoperative MRI to determine the location of organs to help to avoid intraoperative complications during LLIF surgery, especially for patients with ASD.

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  • Hiroaki Kimura, Shunsuke Fujibayashi, Bungo Otsuki, Shuichi Matsuda
    Article ID: 2017-0043
    [Advance publication] Released: February 28, 2018
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    Introduction: Pyogenic arthritis in the spinal facet joint is rare, although the wide availability of magnetic resonance imaging (MRI) has increased the detection rate. Pyogenic arthritis of a lumbar facet joint is often combined with abscesses in the paraspinal muscles and epidural space. However, there is no report of pyogenic arthritis of a lumbar facet joint causing a retroperitoneal abscess. We report on a patient with pyogenic lumbar facet arthritis, which caused a huge retroperitoneal abscess.

    Case Reports: The patient was a 67-year-old woman with a 3-week history of fever and pain in her lower back, left lower abdomen, and left thigh. Blood tests revealed high levels of inflammatory markers. Computed tomography (CT) showed a huge retroperitoneal abscess, and MRI of the lumbosacral spine showed an abscess at the left L5/S facet joint, that had invaded into the paraspinal muscles, epidural space, and retroperitoneal space. We diagnosed pyogenic arthritis of a lumbar facet joint combined with abscesses in the paraspinal muscles, epidural space, and retroperitoneal space. CT-guided percutaneous drainage of the retroperitoneal abscess was performed, and the patient was treated with antibiotics. The bacterial strain cultured was Streptococcus pneumoniae. The patient recovered after 10 weeks of antibiotic treatment combined with additional CT-guided percutaneous drainage.

    Conclusions: Pyogenic arthritis of a lumbar facet joint can cause a retroperitoneal abscess through the vertebral foramen as well as the more common abscesses in the paravertebral muscles and epidural space, and the finding of MRI is characteristic. The clinician should suspect of pyogenic arthritis of a lumbar facet joint in a patient presenting with retroperitoneal abscesses that are not secondary to diseases of kidney or gastrointestinal tract.

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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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  • Yusuke Yamamoto, Eiichiro Iwata, Hideki Shigematsu, Hiroshi Nakajima, ...
    Article ID: 2017-0052
    [Advance publication] Released: February 28, 2018
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    Introduction To identify the temporal comparison of biochemical markers for early detection of surgical site infection (SSI) following instrumented spinal fusion that are not affected by operative factors.

    Materials and methods We reviewed data on C-reactive protein level and total white blood cell count and differential count before instrumented spinal fusion and at 1, 4, and 7 days postoperatively. The 141 patients in our sample were divided into an SSI group (patients who developed deep SSI) and a non-SSI group. We investigated the peak or nadir value day and identified those not affected by operative circumstances (operating time, intraoperative blood loss, and number of fusion segments) in the non-SSI group. If there was a significant difference between the peak or nadir value day and the next survey day, we considered the temporal comparison between these unaffected markers as an indicator of SSI and examined the usefulness of these indicators by calculating sensitivity and specificity. Furthermore, we investigated the usefulness of the combination of these markers (if even each one marker was recognized, we considered it positive).

    Results Four biochemical markers of SSI were selected: neutrophil percentage at postoperative day 4 more than day 1 (sensitivity 36%, specificity 95%), neutrophil count at postoperative day 4 more than day 1 (sensitivity 46%, specificity 93%), lymphocyte percentage at postoperative day 4 less than day 1 (sensitivity 36%, specificity 90%), and lymphocyte count at postoperative day 4 less than day 1 (sensitivity 36%, specificity 90%). The combination of these markers showed sensitivity 100%, specificity 80%, respectively.

    Conclusions Four markers are reliable indicators for early detection of SSI following spinal instrumented fusion because they are not affected by operative factor. The combination of each indicator had both high sensitivity and specificity. Therefore, it is reliable and much useful for early detection of SSI.

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  • Hirokazu Inoue, Hideaki Watanabe, Hitoshi Okami, Atsushi Kimura, Atsus ...
    Article ID: 2017-0054
    [Advance publication] Released: February 28, 2018
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    Introduction: Pulmonary embolism (PE) is a risk of mortality following spine surgery. Many studies have demonstrated that deep venous thrombosis (DVT) may affect and actually advance to PE, but few studies have shown how venous thromboembolism (VTE), including PE and DVT, affect blood markers after spine surgery. In this study, we examined changes in blood markers with PE or DVT after low-risk spine surgery, namely cervical laminoplasty or lumbar laminectomy.

    Methods: Seventy-two spine surgery patients were studied. A 16-row multidetector computed tomography was performed before and 3 d after the surgery. Patients with a history of cerebral vascular accident or arterial thrombotic episode or pre-surgical asymptomatic PE or DVT were excluded. Plasma levels of soluble fibrin monomer complex, D-dimer, plasminogen activator inhibitor type-1 (PAI-1), and white blood cell and platelet counts were measured preoperatively and postoperatively at days 1, 3, and 7.

    Results: No patient developed symptomatic post-surgical VTE. Six patients with asymptomatic PE and six with asymptomatic DVT were detected post-surgery, including one patient with both. D-dimer postoperatively at days 3 and 7 was significantly higher in the post-op PE group than in the no-PE group. PAI-1 preoperatively was significantly higher in the DVT and VTE groups than in the no-DVT and no-VTE groups.

    Conclusions: Elevated D-dimer at postoperative days 3 and 7 is a predictive factor for the early diagnosis of PE after spine surgery. Moreover, elevated PAI-1 preoperatively is a predictive factor for the early diagnosis of DVT and VTE. Consequently, PE may occur through a pathway other than DVT.

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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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  • Naoki Okamoto, Seiichi Azuma
    Article ID: 2017-0064
    [Advance publication] Released: February 28, 2018
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    Introduction

    During upper cervical anterior fusion involving C2, the branches of the superior laryngeal and hypoglossal nerves traversing the operative field are at risk for injury, mainly from excessive retraction and/or incidental ligation. These injuries would cause postoperative dysphagia and/or dysphonia that are often transient but might sometimes persist for several months. The aim of this study was to describe our modified approach for upper cervical anterior fusion and to examine the surgical outcomes and postoperative complications in a small case series.

    Methods

    Four patients underwent upper cervical anterior fusion at our institution. Detaching the omohyoid and sternohyoid muscles from the hyoid bone increased the mobility of the hyoid bone and enabled visualization of the thyrohyoid membrane. This maneuver facilitated access to C2 without excessive retraction to the larynx and the hypoglossal nerve traversing above the hyoid bone. Moreover, this maneuver enabled easy identification and dissection of the internal branch of the superior laryngeal nerve piercing the thyrohyoid membrane.

    Results

    Three patients underwent C2-3 fusion and one patient underwent C2-5 fusion followed by instrumentation. In all patients, wide, adequate exposure of C2 and proper instrumentation was achieved, and both the internal branch of the superior laryngeal nerve and the hypoglossal nerve were identified and preserved. No patient experienced remarkable postoperative dysphagia, dyspnea, and dysphonia. Solid union was achieved in all patients.

    Conclusions

    The technique of detaching the infrahyoid muscles from the hyoid bone during upper cervical anterior fusion involving C2 reduced the traction force to the larynx and the hypoglossal nerve, enabled easy identification of the internal branch of the superior laryngeal nerve, and prevented postoperative complications, such as dysphagia.

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