竹下 克志

IntroductionMicroendoscopic techniques through a unilateral paramedian approach or muscle-preserving techniques using a microscope have been reported as minimally invasive spinal decompression procedures for the cervical spine. In this study, we developed a novel technique, cervical microendoscopic interlaminar decompression (CMID) through a midline approach, for treating cervical compression myelopathy. MethodsA total of 29 consecutive patients with single- or two-level cervical compression myelopathy were reviewed. For the single-level cases (e.g., C5-C6), a midline skin incision, approximate to 2 cm in length, was made at the spinal level to be decompressed (C5-C6) under fluoroscopic guidance. The nuchal ligament was longitudinally cut, and tips of the spinous processes (C5 and C6) were exposed. A 16-mm tubular retractor was inserted between the tips of the C5 and C6 spinous processes. A dome-like laminectomy of C5, partial laminectomy of the upper part of C6, and flavectomy were performed. For the two-level cases (e.g., C4-C5 and C5-C6), the decompression procedure was completed by splitting the spinous process (C5). Pre- and postoperative neurologic status was evaluated using the Japanese Orthopedic Association (JOA) score. Neck and arm pain was also evaluated using a numerical rating scale (NRS). ResultsOverall, 10 patients underwent single-level decompression, and 19 patients underwent two-level decompression. The average age was 67 years (range: 40-83 years), and the mean follow-up period was 11 months (range: 4-14 months). The average pre- and postoperative JOA scores were 10.2 and 13.5, with a mean recovery rate of 49%. The mean preoperative and postoperative NRS scores were 3.5 and 1.5 for neck pain and 4.6 and 2.9 for arm pain, respectively. One patient showed transient mild weakness of the leg that recovered neurologically within a few weeks. No other postoperative complications were observed. ConclusionThis procedure revealed good short-term surgical results. This technique has advantages including (1) a symmetrical orientation of the surgical field, (2) an intermuscular incision that minimizes blood loss and muscle trauma, and (3) the ability to safely complete the decompression procedure without retracting the cervical spinal cord compared with the unilateral approach. Although long-term surgical results are required, this technique is not only safe but also minimally invasive as a treatment for cervical compression myelopathy.

BACKGROUND CONTEXT: The incidence and relevant risk of ischemic stroke after cervical spine trauma remain unknown. PURPOSE: To examine the incidence of ischemic stroke during hospitalization in patients with cervical spine injury, and analyze the impact of different types of cervical spine injuries on the occurrence of ischemic stroke. STUDY DESIGN: Retrospective analysis of data abstracted from the Diagnosis Procedure Combination database, a nationally representative database in Japan. PATIENT SAMPLE: We included all patients hospitalized for any of the following traumas: fracture of cervical spine (International Classification of Diseases, 10th Revision codes: S120, S121, S122, S127, S129); dislocation of cervical spine (S131, S133); and cervical spinal cord injury (SCI) (S141). OUTCOME MEASURES: Outcome measures included all-cause in-hospital mortality and incidence of ischemic stroke (I63) during hospitalization. METHODS: We analyzed the effects of age, sex, comorbidities, smoking status, spinal surgery, consciousness level at admission, and type of cervical spine injury on outcomes. RESULTS: We identified 11,005 patients with cervical spine injury (8,031 men, 2,974 women; mean [standard deviation] age, 63.5 [18] years). According to the types of cervical spine injury, we stratified the patients into three groups: cervical fracture and/or dislocation without SCI (2,363 patients); cervical fracture and/or dislocation associated with SCI (1,283 patients); and cervical SCI without fracture and/or dislocation (7,359 patients). Overall, ischemic stroke occurred in 115 (1.0%) patients during hospitalization (median length of stay, 26 days). In-hospital death occurred in 456 (4.1%) patients. Multivariate analyses showed that ischemic stroke after cervical spine injury was significantly associated with age, diabetes, and consciousness level at admission. The highest in-hospital mortality was observed in patients with cervical fracture and/or dislocation associated with SCI (7.6%), followed by cervical SCI without fracture and/or dislocation (4.0%), and cervical fracture and/or dislocation without SCI (2.6%). Unlike mortality, risks of stroke did not vary significantly among the three groups. CONCLUSIONS: This analysis revealed that ischemic stroke after cervical spine injury was not uncommon and was associated with increased mortality and morbidity. Occurrence of ischemic stroke was significantly associated with age, comorbidities such as diabetes, and consciousness level at admission, but not with the type of spine injury. (C) 2014 Elsevier Inc. All rights reserved.

Study Design. A retrospective study. Objective. To investigate the morphology of the cervical spine in patients with athetoid cerebral palsy (CP), and to evaluate its relationship with the breach of cervical pedicle screws. Summary of Background Data. Cervical pedicle screws have been increasingly used in surgery for patients with CP, but screw misplacement is not uncommon. Although the altered morphology of the cervical spine in patients with CP may result in this high breach rate, few studies have examined the cervical pedicle profile. Methods. We retrospectively analyzed 31 patients with cervical myelopathy with CP, as well as 30 patients with cervical spondylotic myelopathy (CSM), who underwent posterior decompression surgery. The pedicle outer diameter, inner diameter, transverse angle and lateral mass deformity were investigated by obtaining preoperative computed tomographic scans. The accuracy of the placement of 56 pedicle screws used in fusion surgery for 12 patients with CP was also analyzed using postoperative computed tomographic scans. Results. The outer diameter of the pedicle in CP was in the range from 3.3 to 9.6 mm, and was larger than that in CSM at all cervical levels except for C7. Pedicle sclerosis was more frequently observed in CP than in CSM (23% vs. 7.3%, P < 0.001). The transverse angle at C3 and C4 was larger, and lateral mass deformity was more frequently observed in CP than in CSM. The critical breach of pedicle screws in CP was found in 29%. A multivariate analysis revealed that pedicle sclerosis was associated with an increased risk of breach (odds ratio: 6.3; 95% confidence interval: 1.03-39.0; P = 0.047). Conclusion. The pedicle diameter in patients with CP was relatively large, but pedicle sclerosis, a wide transverse angle and lateral mass deformity were frequently observed. Sclerotic pedicles were associated with a higher risk of critical breach.

Objective To examine the magnitude of the adverse impact of high-dose methylprednisolone treatment in patients with acute cervical spinal cord injury (SCI). Methods We examined the abstracted data from the Japanese Diagnosis Procedure Combination database, and included patients with ICD-10 code S141 who were admitted on an emergency basis between 1 July and 31 December in 2007-2009. The investigation evaluated the patients' sex, age, comorbidities, Japan Coma Scale, hospital volume and the amount of methylprednisolone administered. One-to-one propensity-score matching between high-dose methylprednisolone group (>5000 mg) and control group was performed to compare the rates of in-hospital death and major complications (sepsis; pneumonia; urinary tract infection; gastrointestinal ulcer/bleeding; and pulmonary embolism). Results We identified 3508 cervical SCI patients (2652 men and 856 women; mean age, 60.8 +/- 18.7 years) including 824 (23.5%) patients who received high-dose methylprednisolone. A propensity-matched analysis with 824 pairs of patients showed a significant increase in the occurrence of gastrointestinal ulcer/bleeding (68/812 vs 31/812; p<0.001) in the high-dose methylprednisolone group. Overall, the high-dose methylprednisolone group demonstrated a significantly higher risk of complications (144/812 vs 96/812; OR, 1.66; 95% CI 1.23 to 2.24; p=0.001) than the control group. There was no significant difference in in-hospital mortality between the high-dose methylprednisolone group and the control group (p=0.884). Conclusions Patients receiving high-dose methylprednisolone had a significantly increased risk of major complications, in particular, gastrointestinal ulcer/bleeding. However, high-dose methylprednisolone treatment was not associated with any increase in mortality.

Clumsiness and numbness of the upper extremity is one of the most common complaints of patients with cervical myelopathy. However, most previous evaluations after cervical laminoplasty have only been based on physicians' points of view. We used Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) self-report questionnaire, which was designed to measure physical function and symptoms in people with upper-limb disorders to evaluate functional outcomes after laminoplasty. Ninety-four patients who underwent laminoplasty for cervical myelopathy and replied to the questionnaire were included in this study. The average age was 62 years, and mean follow-up period was 61 months. The Japanese Orthopedic Association (JOA) score, Neck Disability Index (NDI), Short-Form Health Questionnaire of 36 questions (physical component score, PCS), upper-extremity pain (Numerical Rating Scale), and QuickDASH (0-100, 0 being least severe) were used to evaluate surgical outcomes. Satisfaction with treatment was also investigated, and internal consistency and criterion-related validity were evaluated. The QuickDASH cutoff value for patient satisfaction was determined by receiver operating characteristic curve (ROC) analysis. The mean total JOA scores were 10 before and 13 after surgery, and average postoperative QuickDASH score was 30. Cronbach alpha of the QuickDASH was 0.94. QuickDASH was significantly correlated with JOA score for upper-extremity motor and sensation, NDI, PCS, and pain. Cutoff value of the QuickDASH was 34.0 by ROC analysis. Significantly better QuickDASH scores were found for patients who were satisfied with treatment than for those who were not, whereas JOA score for upper-extremity motor function did not show a significant difference. QuickDASH had significant correlations with disease-specific JOA scores and other generic outcome measures. Moreover, QuickDASH significantly reflected patients' satisfaction with treatment, whereas the JOA score for upper-extremity motor function did not. QuickDASH was useful in evaluating upper-extremity functional outcomes after cervical laminoplasty.

Objectives. This study aimed to estimate the prevalence, magnitude, and direction of the associations among disability, pain intensity, number of pain sites, and health-related quality of life (HRQoL) in patients reporting low back pain (LBP) as their primary pain. Methods. In January 2009, an Internet survey was performed for randomly selected adults aged 20-79 years who were registered as Internet research volunteers. Of 20 044 respondents, individuals with LBP as the primary pain were analyzed for associations among disability, number of pain sites, and HRQoL. Factors associated with low HRQoL were examined using multiple logistic regression modeling. Results. Of the 20 044 respondents, 25.2 % (n = 5060) reported LBP and 13.5 % (n = 2696) reported LBP as their primary pain. Among those with LBP as the primary pain, HRQoL decreased with increase in disability and number of pain sites. In multivariate analyses, disability [adjusted odds ratio (aOR), 2.93-4.58], number of pain sites (aOR, 1.42-6.12), pain intensity >= 7 (aOR, 1.88), and age >= 60 years (aOR, 1.55) were associated with low HRQoL. Conclusions. Approximately 13.5 % of patients reported LBP as their primary pain. Disability with absence from social activity and >= 7 pain sites were strongly associated with low HRQoL.

An outcome measure to evaluate the neurological function of patients with cervical myelopathy was proposed by the Japanese Orthopaedic Association (JOA score) and has been widely used in Japan. However, the JOA score does not include patients' satisfaction, disability, handicaps, or general health, which can be affected by cervical myelopathy. In 2007, a new outcome measure, the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire (JOACMEQ), which is a self-administered questionnaire, was developed. However, the influence of age and gender on the scores has not been fully examined. The purpose of this study was to establish the standard value of the JOACMEQ by age using healthy volunteers. This study was conducted in 23 university hospitals and their affiliated hospitals from September to December 2011. The questionnaire included 24 questions for evaluation of physical function of the cervical spine and spinal cord. A total of 1,629 healthy volunteers were recruited for the study. The ages ranged from 20 to 89 years old. The volunteers comprised 798 men and 831 women. In the elderly healthy volunteers, the JOACMEQ scores decreased with age. In general, the scores for cervical spine function and upper/lower extremity function were retained up to the 60s, then decreased in the 70s and 80s. The scores for quality of life were retained up to the 70s; however, the score for bladder function was retained up to the 40s, then declined with age from the 50s to 80s. The standard values of the JOACMEQ by age were established. Differences in the scores were found among different generations. Patients with cervical myelopathy should be evaluated with this new self-administered questionnaire taking into account the standard values according to different ages.

We report the case of a female who presented with progressive fusion and an enlargement of the cervical vertebrae. Her cervical deformity gradually progressed with age, and the abnormal bony protrusion into the spinal canal caused myelopathy. We resected the affected vertebrae to decompress the spinal cord and performed combined anterior-posterior spinal fusion. The progression of the spinal deformity and enlargement of vertebrae stopped after surgery. The enlargement of vertebrae in the present case resembled that observed in Proteus syndrome; however, autonomous vertebral fusion has not been reported previously in patients with this condition. Our report may help expand the knowledge on developmental spine disorders.

Study Design. Two-year, prospective cohort data collected for the Japan epidemiological research of Occupation-related Back pain study were used for the analysis. Objective. To identify potential risk factors for the development of new-onset sciatica in initially symptom-free Japanese workers with no history of sciatica. Summary of Background Data. Although the associations between individual and occupational factors and cases of new-onset sciatica are established, the effect of psychosocial factors on the development of sciatica has still not been adequately clarified. Methods. In total, 5310 participants responded to a self-administered baseline questionnaire (response rate: 86.5%). Furthermore, 3194 (60.2%) completed both 1- and 2-year follow-up questionnaires. The baseline questionnaire assessed individual characteristics, ergonomic work demands, and work-related psychosocial factors. The outcome of interest was new-onset sciatica with or without low back pain during the 2-year follow-up period. Incidence was calculated for participants who reported no low back pain in the preceding year and no history of lumbar radicular pain (sciatica) at baseline. Logistical regression assessed risk factors associated with new-onset sciatica. Results. Of 765 eligible participants, 141 (18.4%) reported a new episode of sciatica during the 2-year follow-up. In crude analysis, significant associations were found between new-onset sciatica and age and obesity. In adjusted analysis, significant associations were found for obesity and mental workload in a qualitative aspect after controlling for age and sex. Consequently, in multivariate analysis with all the potential risk factors, age and obesity remained statistically significant (odds ratios: 1.59, 95% confidence interval: 1.01-2.52; odds ratios: 1.77, 95% confidence interval: 1.17-2.68, respectively). Conclusion. In previously asymptomatic Japanese workers, the risk of developing new-onset sciatica is mediated by individual factors. Our findings suggest that the management of obesity may prevent new-onset sciatica.

Objectives: The aim of this study was to evaluate the validity and reliability of the Japanese version of the painDETECT questionnaire (PDQ-J). Materials and Methods: The translation of the original PDQ into Japanese was achieved according to the published guidelines. Subsequently, a multicenter observational study was performed to evaluate the validity and reliability of PDQ-J, including 113 Japanese patients suffering from pain. Results: Factor analysis revealed that the main component of PDQ-J comprises two determinative factors, which account for 62% of the variance observed. Moreover, PDQ-J revealed statistically significant correlation with the intensity of pain (Numerical Rating Scale), Physical Component Score, and Mental Component Score of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). The Cronbach alpha for the total score was 0.78 and for the main component was 0.80. In the analysis of test-retest method, the intraclass correlation coefficient between the two scores was 0.94. Conclusions: We demonstrated the validity and reliability of PDQ-J. We encourage researchers and clinicians to use this tool for the assessment of patients who suffer suspected neuropathic pain.

Rigid screw fixation of C2 including transarticular screw and pedicle screw contain the risk of vertebral artery (VA) injury. On the other hand, translaminar screws are considered to be safer for patients with anomalous VA. But C2 translaminar screw placement was limited in patients who have thin laminas and there is marked variation in C2 laminar thickness. Appropriate C2 fixation method for a patient who has thin laminas and high-riding VA together was controversial. Here, we present a case of an elderly Asian woman who had thin laminas and high-riding VA together with progressive myelopathy to report a first case of C2 spinous process screw insertion. Although the stability and safety of C2 spinous process screw was reported in cadaver series, there was no clinical report to our knowledge. Spinous process screw can be an option of C2 fixation for patients with high-riding VA and severe degenerated cervical spines including thin C2 laminas.

Background: The purpose of this study was to examine how complications in older adults undergoing orthopaedic surgery vary as a function of age, comorbidity, and type of surgical procedure. Methods: We abstracted data from the Japanese Diagnosis Procedure Combination database for all patients aged >= 50 who had undergone cervical laminoplasty, lumbar decompression, lumbar arthrodesis, or primary total knee arthroplasty (TKA) between July 1 and December 31 in the years 2007 to 2010. Outcome measures included all-cause in-hospital mortality and incidence of major complications. We analyzed the effects of age, sex, comorbidities, and type of surgical procedure on outcomes. Charlson comorbidity index was used to identify and summarize patients' comorbid burden. Results: A total of 107,104 patients were identified who underwent cervical laminoplasty (16,020 patients), lumbar decompression (31,605), lumbar arthrodesis (18,419), or TKA (41,060). Of these, 17,339 (16.2%) were aged 80 years or older. Overall, in-hospital death occurred in 121 patients (0.11%) and 4,448 patients (4.2%) had at least one major complication. In-hospital mortality and complication rates increased with increasing age and comorbidity. A multivariate analysis showed mortality and major complications following surgery were associated with advanced age (aged >= 80 years; odds ratios 5.88 and 1.51), male gender, and a higher comorbidity burden (Charlson comorbidity index >= 3; odds ratio, 16.5 and 5.06). After adjustment for confounding factors, patients undergoing lumbar arthrodesis or cervical laminoplasty were at twice the risk of in-hospital mortality compared with patients undergoing TKA. Conclusions: Our data demonstrated that an increased comorbid burden as measured by Charlson comorbidity index has a greater impact on postoperative mortality and major complications than age in older adults undergoing orthopaedic surgery. After adjustment, mortality following lumbar arthrodesis or cervical laminoplasty was twice as high as that in TKA. Our findings suggest that an assessment of perioperative risks in elderly patients undergoing orthopaedic surgery should be stratified according to comorbidity burden and type of procedures, as well as by patient's age.

STUDY DESIGN.: A retrospective multicenter study. OBJECTIVE.: To identify risk factors for postoperative complications associated with growing-rod (GR) surgery for early-onset scoliosis (EOS). SUMMARY OF BACKGROUND DATA.: Results and complications of GR surgery for EOS have not been adequately studied. METHODS.: We evaluated clinical and radiographical results from 88 patients with EOS who underwent GR surgery in 12 spine centers in Japan. The mean age at the time of initial surgery was 6.5 ± 2.2 years (range, 1.5-9.8 yr) and the mean follow-up period was 3.9 ± 2.6 years (range, 2.0-12.0 yr). Risk factors for postoperative complications were analyzed using binomial multiple logistic regression analysis. We considered the potential factors of sex, age, number of rod-lengthening procedures, whether a pedicle screw foundation was used, the uppermost level of the proximal foundation and lowermost level of the distal foundation, Cobb angles of the proximal thoracic, main thoracic, and lumbar curves, and the kyphosis angles in the proximal, main thoracic, thoracolumbar, and lumbar spine. Kaplan-Meier analysis was used to determine the complication-free survival rate of GR surgery as a function of the number of surgical procedures. RESULTS.: Complications affected 50 of the patients (57%) and were associated with 119 of 538 surgical procedures, with 86 implant-related failures (72%), 19 infections (16%), 3 neurological impairments (3%), and 11 other complications. The most frequent implant-related failure was dislodged implant (71%) and 95% of the dislodgements occurred at the proximal foundation. Kaplan-Meier analysis demonstrated a linear decrease in complication-free rates as the number of rod-lengthening procedures increased. Binomial multiple logistic regression analysis found the following significant independent risk factors: 6 or more rod-lengthening procedures (odds ratio [OR], 6.534), an increase of every 20 in the proximal thoracic Cobb angle (OR, 3.091), and an increase of every 25 in the lumbar lordosis angle (OR, 2.607) in the preoperative condition. CONCLUSION.: Increases in the upper thoracic scoliotic curve, thoracic kyphosis, and number of rod-lengthening procedures are positively associated with an increased risk of complications after GR surgery for EOS.Level of Evidence: 4 © 2013, Lippincott Williams &amp Wilkins.

The Neck Disability Index (NDI) is one of the most widely used questionnaires for neck pain. The purpose of this study was to validate the Japanese NDI. We performed two surveys with an 8-week interval in 130 patients with neck pain, radiculopathy and myelopathy. We asked patients to answer two versions of the Japanese NDI: the original NDI, which had been completed by a forward-backward translation procedure, and the modified NDI, which has the phrase "because of neck pain" to the phase "because of neck pain or numbness in the arm." The other parameters examined were the strength of pain and numbness, the Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire, the Hospital Anxiety and Depression Scale, and Short Form 36. Attending surgeons judged the symptom severity. Patients were asked to report the patient global impression of change (PGIC) at the second survey. The internal consistency, criterion-related and discriminative validity, and reliability were evaluated. The original NDI and the modified NDI were 26.9 +/- A 17.1 and 29.9 +/- A 15.5, respectively. The Cronbach alpha values of the original NDI and the modified NDI were 0.92 and 0.89, respectively. Both versions of the NDI had good to excellent correlative coefficients with the related domains. The modified NDI had a higher validity for numbness and mental health-related QOL. The symptom severity was significantly correlated with the modified NDI. The intraclass correlation coefficients of the two surveys of the modified and original NDI were comparable. The effect sizes of the modified and the original NDI were 0.64 and 0.55, respectively. Spearman's rho between the change of the NDI and the PGIC was 0.47 in the original NDI and 0.59 in the modified NDI. We demonstrated the validity, reliability and responsiveness of the Japanese NDI. The modified NDI was more strongly correlated with numbness and mental health-related QOL.

INTRODUCTION Abiotrophia species have been referred to as nutritionally variant streptococci because of their fastidious nutritional requirements for growth. Abiotrophia species are difficult to identify with conventional solid culture. PRESENTATION OF CASE A 48-year-old woman was admitted to our hospital with severe low back pain and body temperature of 38.2 C. Magnetic resonance imaging revealed edema and contrast enhancement of the L4 and L5 vertebral bodies with high signal intensity in the L3-4 and L4-5 intervertebral discs on the T2-weighted images. The patient underwent needle biopsy of the L3-4 disk. Cultures of disk biopsy samples and blood yielded gram positive cocci in short chains with scanty growth on chocolate agar. Further subculture with supplemented medium and subsequent 16S ribosomal RNA gene sequencing identified the pathogen as Abiotrhophia adiacens. The patient was treated with intravenous ampicillin. At 6-month follow-up, the patient was free of symptoms. DISCUSSION Causative microorganisms remain unidentified in 25-40% of spinal infection cases. Abiotrophia species grow poorly on conventional solid media, and require pyridoxal or thiol group supplementation. Use of Brucella HK agar or GAM agar plate is helpful for detection of Abiotrophia species. We first confirmed the diagnosis by direct identification of Abiotrophia adiacens from infected disk. Abiotrophia species are one of the major pathogens of infective endocarditis accounting for 5% of cases. Considering their fastidious nature, it is likely that most cases of Abiotrophia discitis are falsely classified as culture-negative discitis therefore, their role in pyogenic discitis may be underestimated. CONCLUSION Subculture using nutritionally supplemented media is crucial for their identification. © 2013 The Authors.

BACKGROUND CONTEXT: Despite potentially devastating consequences, pulmonary embolism (PE) in patients undergoing spinal surgery remains poorly understood. To the best of our knowledge, few large studies have examined the prevalence and risk factors of PE after spinal surgery. PURPOSE: To investigate the prevalence of symptomatic PE in patients undergoing elective spinal surgery and to identify clinical variables associated with the occurrence of postoperative PE. STUDY DESIGN: A retrospective analysis of data abstracted from the diagnosis procedure combination (DPC) database, a nationally representative database in Japan. PATIENT SAMPLE: We included all patients with a diagnosis of spinal canal stenosis, disc herniation, spondylosis, spondylolisthesis, trauma, metastatic tumor, or infection who underwent spinal surgery between July 1 and December 31 of 2007 and 2008, respectively. OUTCOME MEASURES: The primary end point was defined as the occurrence of postoperative PE during hospitalization. The secondary end point was in-hospital death after postoperative PE. METHODS: We analyzed the association between the occurrence of postoperative PE and clinical variables recorded in the DPC database, including age, sex, comorbidities, location of surgery, primary diagnosis, anterior/posterior approach, use of instrumentation, and duration of anesthesia. RESULTS: A total of 47,743 patients were identified. Of these, 50 (0.10%) developed PE and four died as a result of PE. Logistic regression analyses revealed that occurrence of PE was associated with older age (70 years or older; odds ratio [OR], 3.15; 95% confidence interval [CI], 1.15-8.69; p=5.026) and longer anesthesia time (more than 360 minutes; OR, 2.19; 95% CI, 0.88-5.44; p=5.092). Patients with trauma were significantly more likely to have a PE than those with spinal canal stenosis (0.27% vs. 0.09%; OR, 2.86; 95% CI, 1.14-7.18; p=5.026). CONCLUSIONS: This retrospective analysis of a nationally representative database identified older age, longer anesthesia time, and spinal trauma as risk factors for increased incidence of postoperative PE. Surgeons should be aware of the increased risk of postoperative PE in these subgroups of patients. (C) 2012 Elsevier Inc. All rights reserved.

Neck pain is a common health problem that restricts activities of daily living. The Neck Disability Index (NDI) was developed to assess disability in patients with neck pain. The normative score and the cut-off value are mandatory to assess an individual patient or a certain patient group for clinically important neck pain with disability, by distinguishing it from nonsignificant pain. The objective of the present study was to determine the normative score and the cut-off value of the NDI. A total of 1,200 participants who registered with an internet research company were interviewed on the website about their episodes of neck pain during the previous 4 weeks, and completed the online NDI questionnaire. If the participants reported neck pain, they were also asked about the disability in activity of daily living it caused, and the presence of associated symptoms in upper limbs. Disability was defined according to the consensus study on the standardization of back pain definitions. The normative score was determined by calculating the mean in the participants, and the cut-off value was determined by the receiver-operating characteristic curve analysis. The prevalence of neck pain was 37.8 %. Demographic data of the participants also indicated that they were representative of the normal population in Japan. The mean score was 6.98, and the median was 2. The NDI score was higher in middle age, and at its peak in the 50s age group (50-59 years of age). The female mean was significantly higher. The NDI score was higher in those with upper limb symptoms. We have determined the cut-off value of the NDI to detect neck pain associated with disability to be 15. The normative score and the cut-off value of the NDI were determined. Our cut-off value is potentially useful in evaluating the therapeutic effectiveness of various interventions for neck pain.

Study Design. A retrospective comparative study. Objective. To investigate natural course and prognostic factors in patients with mild forms of cervical spondylotic myelopathy (CSM), focusing on intramedullary increased signal intensity (ISI) on T2-weighted magnetic resonance imaging. Summary of Background Data. Long-term natural course of mild forms of CSM, especially with ISI on magnetic resonance imaging, remains uncertain. Methods. Patients with CSM who visited our institution between 1992 and 2004 and did not undergo surgery at first visit were retrospectively reviewed. The inclusion criteria were as follows: (1) motor function Japanese Orthopedic Association scores of 3 or more in both upper and lower extremities and (2) cervical spinal cord compression with ISI on T2-weighted magnetic resonance imaging. There were 45 patients, with a mean follow-up period of 78 months (range, 24 208). We investigated long-term natural history by setting the timing of conversion to surgery due to neurological deterioration as an end point. We further compared prognostic parameters between patients who converted to surgery and those who continued to be followed up nonsurgically. Results. Sixteen patients gradually deteriorated and underwent decompression surgery, whereas 27 patients did not. Apart from these, 2 patients with acute spinal cord injury after minor trauma underwent surgery. Kaplan-Meier survival analysis revealed that 82% or 56% of patients did not require surgery 5 or 10 years after the initial treatment, respectively. As for prognostic factors, Cox proportional hazard analysis revealed that total cervical range of motion (hazard ratio: 3.25), segmental kyphosis in the maximum compression segment (hazard ratio: 4.51), and local slip (hazard ratio: 4.67) were statistically significant. Conclusion. Fifty-six percent of patients with clinically mild CSM with ISI had not deteriorated or undergone surgery at 10 years. Large range of motion, segmental kyphosis, and instability at the narrowest canal were considered to be adverse prognostic factors.

The Oswestry Disability Index (ODI) is one of the most common scoring systems used for patients with low back pain (LBP). Although the normative score of the ODI was reported to be 10.19 in a review article, no study has calculated the normative score after adjusting the value based on the age distribution. In addition, none of the previous studies has estimated the cut-off value which separates LBP with disability from LBP without disability. The purpose of this study was to estimate the normative score by adjusting the data for age distribution in Japan, and to determine the cut-off value which separates LBP with disability from LBP without disability. We conducted an internet survey on LBP using the Japanese version of the ODQ. A total of 1,200 respondents, composed of 100 males and 100 females in each age group (from the 20s to 70s), participated in this study. We also asked them to provide information about their backgrounds. We estimated the normative score after correcting for the age distribution of Japan. We also estimated the ODI of those with or without disability, the factors associated with the ODI, and the cut-off value which separates LBP with disability from LBP without disability. The participants' backgrounds were similar to the national survey. The normative score of the ODI was estimated at 8.73. The ODI of the LBP with disability group was 22.07. Those with sciatica and obese subjects showed higher ODI than those without. The optimal cut-off value was estimated to be 12. We defined the normative score and the cut-off value of the ODI.

Study Design. Two-year, prospective cohort data from the Japan epidemiological research of occupation-related back pain study were used for this analysis. Objective. To examine the association between a new onset of low back pain (LBP) with disability and potential risk factors among initially symptom-free Japanese workers. Summary of Background Data. Despite strong evidence that psychosocial issues may influence LBP onset among symptom-free persons, these and other LBP risk factors have not been well investigated in the Japanese workplace. Methods. Of 5310 participants responding to a self-administered baseline questionnaire (response rate: 86.5%), 3194 (60.2%) completed both 1- and 2-year follow-up questionnaires. The baseline questionnaire assessed individual characteristics, ergonomic work demands, and work-related psychosocial factors. The outcome of interest was new-onset LBP with disability during the follow-up period. Incidence was calculated for the participants who reported no LBP during the past year at baseline. Logistic regression was used to explore risk factors associated with new-onset LBP with disability. Results. Of 836 participants who were symptom-free during the preceding year, 33 (3.9%) reported LBP with disability during the 2-year follow-up. In univariate analyses, "history of LBP," "frequent lifting," " interpersonal stress at workplace," and " monotonous tasks" were all significant predictors of LBP incidence. All of these factors remained statistically significant or almost significant in the multivariate analysis adjusting for the other variables as well as age and sex: adjusted odds ratio (OR) and 95% confidence interval (95% CI) for history of LBP (OR: 3.25, 95% CI: 1.53-6.91), frequent lifting (OR: 3.77, 95% CI: 1.16-12.3), interpersonal stress at workplace (OR: 2.42, 95% CI: 1.08-5.43), and monotonous tasks (OR: 2.21, 95% CI: 0.99-4.94). Conclusion. Both ergonomic and work-related psychosocial factors may predict the development of LBP with disability among previously asymptomatic Japanese workers. Thus, workplace interventions aimed at reducing the incidence of LBP should focus on both ergonomic and psychosocial stress.

Paralysis in spinal metastasis is often caused by anterior dural compression, and anterior approach has been frequently chosen for decompression despite its dreadful complications. On the other hand, the effectiveness of posterior indirect decompression has not specifically established. The objective of the present study was to investigate the anatomical patterns of dural compression, and to clarify the effectiveness of posterior surgery for anterior lesions. We retrospectively analyzed the anatomical patterns of spinal metastasis on MRI images and the neurological recovery in the paralytic patients who underwent posterior decompression and fusion surgery with intraoperative radiation therapy. The recovery rate was compared between those with an anterior or circumferential dural compression (A+), who were indirectly decompressed, and those with a posterior and/or lateral dural compression (A-), who were directly decompressed. A total of 135 cases were included in the study, and 81.5% had anterior dural compression (A+). In the A+ group, 88.2% of preoperatively non-ambulatory cases regained the gait. Full recovery was achieved in 50% of preoperatively ambulatory cases. These rates were not significantly different from those in the A- group. The rate of gait regain was diminished in the surgeries of the middle thoracic spine (T5-8). Most spinal metastases cause paralysis by anterior compression; however, the result of posterior indirect decompression was similar to that of posterior direct decompression, although kyphosis negatively affected the result. Anterior decompression might not always be necessary for soft tumor compression as long as the adjuvant therapy is effective for the local control.

Background: The impact of dialysis dependence on perioperative risks following spinal surgery is not fully understood. The purposes of the present study were to determine the perioperative risks in dialysis-dependent patients treated with spinal surgery and to examine whether the presence of destructive spondyloarthropathy further increases perioperative risks. Methods: We examined abstracted data from the Diagnosis Procedure Combination database in a retrospective analysis of a nationally representative inpatient database. The survey of the database is conducted annually for a six-month period between July 1 and December 31. The data from 2007 and 2008 were used for this study. We included all patients who had undergone any combination of,laminectomy, laminoplasty, discectomy, and/or spinal arthrodesis. For analysis, dialysis-dependent patients were further classified into subgroups with or without destructive spondyloarthropathy. Results: We identified 51,648 eligible patients (30,743 men and 20,905 women; mean age, sixty-two years), including 869(1.7%) who were dialysis-dependent. Of the latter, ninety-five had destructive spondyloarthropathy. Overall in-hospital mortality was 0.41%. Dialysis-dependent patients had a significantly higher in-hospital mortality rate than non-dialysis-dependent patients. After adjustment, dialysis-dependent patients remained at a tenfold higher risk for in-hospital death. Dialysis-dependent patients were also at significantly greater risk for postoperative major complications. The rate of complications in dialysis-dependent patients with destructive spondyloarthropathy was 65% higher than that in those without destructive spondyloarthropathy, but this difference did not reach significance. Conclusions: Dialysis-dependent patients had a tenfold higher risk of in-hospital death than did non-dialysis-dependent patients. Dialysis-dependent patients were also more likely to have major complications such as cardiac events, sepsis, and respiratory complications. Our data also indicate that the presence of destructive spondyloarthropathy is associated with a higher rate of postoperative complications in dialysis-dependent patients.,

Study Design. Retrospective analysis. Objective. We evaluated the aorta safety in placement of a right pedicle screw in scoliotic patients. Summary of Background Data. Past reports emphasized the aorta risk in placing pedicle screws on the concave left side in right thoracic scoliosis. However, risk on the right side has drawn limited interest. Methods. Thirty-four scoliotic patients with an average age of 18.0 years were evaluated. The Cobb angle averaged 59.0 degrees +/- 14.0 degrees. From computed tomographic data, we evaluated the aorta location relative to the spine at each level from T4 to L4 and simulated placement of a right pedicle screw with a direction different from the ideal trajectory. Sensitivity analysis was performed independently by variable direction errors and screw length: the maximum error of trajectory was set to 5 degrees in the medial direction and to 5 degrees, 10 degrees, or 20 degrees in the lateral direction, and a screw length was set at 40, 45 or 50 mm. We defined "aorta-at-risk" when a patient has some level where a simulated pedicle screw involves the aorta, and compared the curve characteristics (the apical vertebral translation, the Cobb angle and the Nash-Moe grade) between the aorta-at-risk cases and the aorta-no-risk cases. Results. In left thoracic or lumbar curves, the aorta often resided in front of right pedicles at the periapical level. In a scenario of a simulated pedicle screw with a maximum error of 20 degrees in the lateral direction and a screw length of 50 mm, the aorta was at risk in 7 (33%) of 21 left lumbar curves. Curve characteristics of the aorta-atrisk cases at L1 were a larger apical vertebral translation (P = 0.003), a larger Cobb angle (P = 0.006), and a larger Nash-Moe grade (P = 0.017) compared with those of the aorta-no-risk cases. Conclusion. Surgeons need to pay attention to the position of the aorta in placing a pedicle screw on the right at the periapical level of a left curve either in thoracic or lumbar spine.

Object. The aim of this study was to evaluate the outcomes of fusion surgery in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to identify factors significantly related to surgical outcomes. Methods. The study included 76 patients (34 men and 42 women with a mean age of 56.3 years) who underwent fusion surgery for T-OPLL at 7 spine centers during the 5-year period from 2003 to 2007. The authors evaluated the patient demographic data, underlying disease, preoperative comorbidities, history of spinal surgery, radiological findings, surgical methods, surgical outcomes, and complications. Surgical outcomes were assessed using the Japanese Orthopaedic Association (JOA) scale score for thoracic myelopathy (11 points) and the recovery rate. Results. The mean JOA scale score was 4.6 +/- 2.1 points preoperatively and 7.7 +/- 2.5 points at the time of the final follow-up examination, yielding a mean recovery rate of 45.4% +/- 39.1%. The recovery rates by surgical method were 38.5% +/- 37.8% for posterior decompression and fusion, 65.0% +/- 35.6% for anterior decompression and fusion via an anterior approach, 28.8% +/- 41.2% for anterior decompression via a posterior approach, and 57.5% +/- 41.1% for circumferential decompression and fusion. The recovery rate was significantly higher in patients without diabetes mellitus (DM) than in those with DM. One or more complications were experienced by 31 patients (40.8%), including 20 patients with postoperative neurological deterioration, 7 with dural tears, 5 with epidural hematomas, 4 with respiratory complications, and 10 with other complications. Conclusions. The outcomes of fusion surgery for T-OPLL were favorable. The absence of DM correlated with better outcomes. However, a high rate of complications was associated with the fusion surgery. (DOI: 10.3171/2011.6.SPINE10816)

Study Design. Retrospective multicenter study. Objective. To review the clinical characteristics of traumatic cervical spinal cord injury (SCI) associated with ossification of the posterior longitudinal ligament (OPLL). Summary of Background Data. Despite its potentially devastating consequences, there is a lack of information about acute cervical SCI complicated by OPLL. Methods. This study included consecutive patients with acute traumatic cervical SCI (Frankel A, B, and C) who were admitted within 48 hours of injury to 34 spine institutions across Japan. For analysis of neurologic outcome, patients who had completed at least a 6-month follow-up were included. Neurologic improvement was defined as at least one grade conversion in Frankel grade. Results. A total of 453 patients were identified (367 men, 86 women; mean age, 59 years). OPLL was found in 106 (23%) patients (87 men, 19 women; mean age, 66 years). Most of the patients with OPLL (94 of 106) were without bone injury, presenting with incomplete SCI. The prevalence of OPLL reached 34% in SCI without bone injury. The cause of SCI was predominantly falls (74%). Only 25% of the patients were aware of OPLL. Half of the OPLL patients reported gait disturbance before injury. Forty-eight (52%) OPLL patients without bone injury underwent surgery (median, 13.5 days after injury), mostly laminoplasty. Overall, no significant difference was noted in neurologic improvement between surgery group and conservative group. However, further stratification showed that surgery was associated with greater neurologic recovery in patients who had gait disturbance before injury (P = 0.04). Conclusion. Prevalence of OPLL among cervical SCI was alarmingly high, especially in those without bone injury. Most of cervical SCI associated with OPLL were incomplete, without bone injury, and caused predominantly by low-energy trauma. The majority of the patients were unaware of OPLL. Surgery produced better neurologic recovery in patients who had gait disturbance before injury.

Study Design. Retrospective multi-institutional study. Objective. To investigate the incidence of neurological deficits after cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL). Summary of Background Data. According to analysis of long-term results, laminoplasty for cervical OPLL has been reported as a safe and effective alternative procedure with few complications. However, perioperative neurological complication rates of laminoplasty for cervical OPLL have not been well described. Methods. Subjects comprised 581 patients (458 men and 123 women; mean age: 62 + 10 years; range: 30-86 years) who had undergone laminoplasty for cervical OPLL at 27 institutions between 2005 and 2008. Continuous-type OPLL was seen in 114, segmental-type in 146, mixed-type in 265, local-type in 24, and not judged in 32 patients. Postoperative neurological complications within 2 weeks after laminoplasty were analyzed in detail. Cobb angle between C2 and C7 (C2/C7 angle), maximal thickness, and occupying rate of OPLL were investigated. Pre- and postoperative magnetic resonance imaging was performed on patients with postoperative neurological complications. Results. Open-door laminoplasty was conducted in 237, double-door laminoplasty in 311, and other types of laminoplasty in 33 patients. Deterioration of lower-extremity function occurred after laminoplasty in 18 patients (3.1%). Causes of deterioration were epidural hematoma in 3, spinal cord herniation through injured dura mater in 1, incomplete laminoplasty due to vertebral artery injury while making a trough in 1, and unidentified in 13 patients. Prevalence of unsatisfactory recovery not reaching preoperative level by 6-month follow-up was 7/581 (1.2%). Mean occupying rate of OPLL for patients with deteriorated lower-extremity function was 51.2 +/- 13.6% (range, 21.0%-73.3%), significantly higher than the 42.3 +/- 13.0% for patients without deterioration. OPLL thickness was also higher in patients with deterioration (mean, 6.6 +/- 2.2 mm) than in those without deterioration (mean, 5.7 +/- 2.0 mm). No significant difference in C2/C7 lordotic angle was seen between groups. Conclusion. Although most neurological deterioration can be expected to recover to some extent, the frequency of short-term neurological complications was higher than the authors expected.

Spinal extradural arachnoid cysts are thought to be extradural arachnoid pouches that communicate with the intraspinal subarachnoid space through a small dural defect. The mainstay of current treatment is resection of the cyst wall followed by obliteration of the communicating pedicle. Despite it:; clinical importance, the communicating pedicle of the cyst is often elusive. The authors report a 57-year-old woman with an extradural arachnoid cyst with intractable back pain and progressive motor weakness. Preoperative imaging studies, including phase-contrast MRI, failed to identify the communicating pedicle. Intraoperative Doppler ultrasonography clearly demonstrated the pulsatile influx of cerebrospinal fluid into the cyst. A flap-like structure was also noted near the pedicle; this structure appeared to act as a one-way valve. Doppler ultrasonography may be a helpful adjunct for identifying the location of elusive communication in a spinal extradural arachnoid cyst. (c) 2010 Elsevier Ltd. All rights reserved.

Study Design. Retrospective analysis. Objective. To evaluate movement of the aorta in patients with scoliosis who have undergone the posterior correction and fusion. Summary of Background Data. Surgeons check preoperative imaging for pedicle screw placement, but past analyses indicated that the aorta shifts after scoliosis surgery. Few studies, however, evaluated the aorta movement in detail. Methods. A total of 22 patients with a right thoracic curve underwent posterior instrumentation and fusion. The average age at surgery was 17.2 years. The average of the preoperative Cobb angle was 65.2 degrees which decreased to 20.0 degrees. Computed-tomographic data were analyzed by multiplanar reconstruction. In our coordinate system, the middle of the base of the left superior facet was set as the origin and a line connecting the middle points of both bases of the superior facets was defined as the X-axis. We defined the angle and the distance to describe the aorta position and analyzed the movement of the aorta relative to the spine. Deformity parameters were examined to determine their correlation with the aorta parameters. We simulated variable pedicle screw placement and defined a warning pedicle when the aorta enters the expected area of the screw and examined them in 24 scenarios. Results. The aorta moved 4.7 +/- 3.0 mm on an average. The aorta had a tendency to migrate in the anteromedial direction and this movement correlated with preoperative apical vertebral translation, preoperative sagittal alignment, and change of sagittal alignment. The ratio of warning pedicles at the middle thoracic level (T7-T9) increased after deformity correction. Conclusion. The aorta moved anteromedially relative to the spine after the posterior correction and the risk of the aorta by a pedicle screw increased by correction of the deformity at the middle thoracic spine. Surgeons are recommended to anticipate the aorta movement in the surgical planning.

A retrospective study was performed to determine the sensitivities of the pyramidal signs in patients with cervical myelopathy, focusing on those with increased signal intensity (ISI) in T2-weighted magnetic resonance imaging (MRI). The relationship between prevalence of the pyramidal signs and the severity of myelopathy was investigated. We reviewed the records of 275 patients with cervical myelopathy who underwent surgery. Of these, 143 patients were excluded from this study due to comorbidities that might complicate neurological findings. The MR images of the remaining 132 patients were evaluated in a blinded fashion. The neurological findings of 120 patients with ISI (90 men and 30 women; mean age 61 years) were reviewed for hyperreflexia (patellar tendon reflex), ankle clonus, Hoffmann reflex, and Babinski sign. To assess the severity of myelopathy, the motor function scores of the upper and lower extremities for cervical myelopathy set by the Japanese Orthopaedic Association (m-JOA score) were used. The most prevalent signs were hyperreflexia (94%), Hoffmann reflex (81%), Babinski sign (53%), and ankle clonus (35%). Babinski sign (P < 0.001), ankle clonus, and Hoffmann reflex showed significant association with the lower m-JOA score. Conversely, no association was found with the upper m-JOA score. In patients with cervical myelopathy, hyperreflexia showed the highest sensitivity followed by Hoffmann reflex, Babinski sign, and ankle clonus. The prevalence of the pyramidal signs correlated with increasing severity of myelopathy. Considering their low sensitivity in patients with mild disability, the pyramidal signs may have limited utility in early diagnosis of cervical myelopathy.

Object. The aim in this prospective study was to determine the morphological limitations of laminoplasty for cervical ossification of the posterior longitudinal ligament (OPLL) by using intraoperative ultrasonography and to investigate correlations between ultrasonographic findings and 2-year follow-up results. Methods. Included in this study were 40 patients who underwent double-door laminoplasty for cervical myelopathy due to OPLL. Intraoperative ultrasonography was used to evaluate posterior shift of the spinal cord after the posterior decompression procedure. To determine the decompression status of the cord, the authors classified ultrasonographic findings into 3 types on the basis of the presence or absence of spinal cord contact with OPLL after decompression: Type 1, noncontact; Type 2, contact and apart; and Type 3, contact. Patients were divided accordingly into Group 1, showing Type I or 2 findings, representing sufficient decompression; and Group 2, showing Type 3 findings with insufficient decompression. Preoperative sagittal alignment of the cervical spine (C2-7 angle) and preoperative maximal thickness of OPLL were compared between groups. The authors also investigated the morphological limitations of laminoplasty and 2-year follow-up results by using the Japanese Orthopedic Association (JOA) scoring system. Results. According to receiver operating characteristic curve analysis, an OPLL maximal thickness > 7.2 mm was a cutoff value for insufficient decompression. However, sufficient or insufficient decompression did not correlate with 2-year results, as determined by JOA scores. The C2-7 angle had no impact on ultrasonographic findings. Conclusions. Laminoplasty has a morphological limitation for thick OPLLs, and a thickness > 7.2 mm represents a theoretical cutoff for residual cord compression after laminoplasty. According to 2-year results, however, laminoplasty can remain the first choice for any type of multiple-level OPLL. (DOI: 10.3171/2010.3.SPINE09680)

Parameters of the position of the aorta in previous reports were determined for anterior surgery. This study evaluated the relative position of the aorta to the spine by new parameters, which could enhance the safety of pedicle screw placement. Three parameters were defined in a new Cartesian coordinate system. We selected an entry point of a left pedicle screw as the origin. The transverse plane was determined to include both the bases of the superior facet and to be parallel to the upper endplate of the vertebral body. A line connecting the entry points of both sides was defined as the X-axis. The angle formed by the Y-axis and a line connecting the origin and the center of the aorta was defined as the left pedicle-aorta angle. The length of a line connecting the origin and the aorta edge was defined as the left pedicle-aorta distance. Distance from the edge of the aorta to the X-axis was defined as the pedicular line-aorta distance. These parameters were measured preoperatively in 293 vertebral bodies of 24 patients with a right thoracic curve. We simulated the placement of the pedicle screw with variable length and with some direction error. We defined a warning pedicle as that when the aorta enters the expected area of the screw. Sensitivity analysis was performed to find the warning pedicle ratio in 12 scenarios. The left pedicle-aorta angle averaged 29.7A degrees at the thoracic spine and -16.3A degrees at the lumbar spine; the left pedicle-aorta distance averaged 23.7 and 55.2 mm; the pedicular line-aorta distance averaged 18.3 and 51.0 mm, respectively. The ratio of warning pedicles was consistently high at T4-5 and T10-12. When a left pedicle screw perforates an anterior/lateral wall of the vertebral body, the aorta may be at risk. These new parameters enable surgeons to intuitively understand the position of the aorta in surgical planning or in placement of a pedicle screw.

Since sleep apnea is a risk factor for high mortality of rheumatoid arthritis (RA) patients, this study examined the prevalence in RA patients with occipitocervical lesions, and the associated radiographic features. Twenty-nine RA patients requiring surgery for progressive myelopathy due to occipitocervical lesions (3 males, 26 females, average age 65 years) were preoperatively evaluated. Twenty-three (79%) had sleep apnea defined as apnea-hypopnea index > 5 events per hour measured by a portable monitoring device, and all of them were classified as the obstructive type. Among gender, age, bone mass index (BMI), and radiographic parameters related to occipitocervical lesions: atlantodental interval (ADI), cervical angles (O/C1, C1/2, and C2/6), and cervical lengths (O-C2 and O-C6), the ADI and cervical lengths were shown to be significantly associated with the presence of sleep apnea by parametric statistical analysis. Since there were positive correlations between the ADI and cervical lengths by Pearson's test, we performed a multivariate logistic regression analysis after adjustment for confounding factors and found that small ADI was the principle parameter associated with sleep apnea. We therefore conclude that the prevalence of sleep apnea is higher than that in a general RA population that was reported previously, and believe that occipitocervical lesions are an independent risk factor for this condition. Small ADI and short neck, secondary to the vertical translocation by RA, may cause obstructive sleep apnea, probably through mechanical or neurological collapse of the upper airway.

The authors developed an original procedure, modified fenestration with restorative spinoplasty (MFRS) for the treatment Of lumbar spinal stenosis. The first step is to cut the spinous process in an L-shape, which is caudally reflected. This procedure allows easy access to the spinal canal, including lateral recesses, and makes it easy to perform a trumpet-style decompression of the nerve roots without violating the facet joints. After the decompression of neural tissues, the spinous process is anatomically restored (spinoplasty). The clinical outcomes at 2 years were evaluated using the Japanese Orthopaedic Association (JOA) scale and patients' satisfaction. Radiological follow-up included radiographs and CT. Between January 2000 and December 2002, 109 patients with neurogenic intermittent claudication with or without mild spondylolisthesis underwent MFRS. Of these, 101 were followed up for at least 2 years (follow-up rate 93%). The average score on the self-administered JOA scale in 89 patients without comorbidity causing gait disturbance improved from 13.3 preoperatively to 22.9 at 2 years' follow-up. Neurogenic intermittent claudication disappeared in all cases. The patients' assessment of treatment satisfaction was "satisfied" in 74 cases, "slightly satisfied" in 12, "slightly dissatisfied" in 2, and "dissatisfied" in I case. In 16 cases (18%), a minimum progression of slippage occurred, but no symptomatic instability or recurrent stenosis was observed. Computed tomography showed that the lateral part of the facet joints was well preserved, and the mean residual ratio was 80%. The MFRS technique produces an adequate and safe decompression of the spinal canal, even in patients with narrow and steep facet joints in whom conventional fenestration is technically demanding. (DOI: 10.3171/2009.2.SPINE08358)

Study Design. A morphometric study of thoracic and lumbar spine in scoliosis. Objective. The purpose of the present study was to evaluate the appropriate values of diameter, length, and direction of pedicle screws with a straightforward trajectory in scoliosis. Summary of Background Data. Several authors have analyzed the pedicle shape and evaluated the feasibility of pedicle screws in the scoliotic spine. To date, however, none of them have reported analysis by multiplanar reconstruction of computed tomography. Methods. Computed tomography with a thickness of 1.25 mm was obtained before surgery in 41 Japanese with scoliosis. A total of 1100 pedicles were evaluated by simulating screw placement with the straightforward approach in a multiplanar reconstruction image. We chose the optimal slice where the insertion point and direction were determined to get the largest diameter of a screw in every vertebra. Length from the insertion point to the tip of the simulated screw was measured. Results. Screws of L1 and L2 were significantly smaller than those of T12 and L3 (P < 0.001). On the concave side, 37% of T3-T9 pedicles did not accept a 4-mm diameter screw even with 25% expansion. Length on the convex side was shorter at T5 and T7-T9 than that on the concave side (P < 0.05). On the convex side, 11% at T4-T8 vertebrae did not accept a 25-mm length screw. Average angle of screws of T1, T2, and L5 was greater than 15 and 17% of the screws at T7-T10 were placed in the lateral direction. Conclusion. In T3-T9 on the concave side, pedicle screws with a straightforward trajectory are not held within 37% of pedicles even with plastic deformation. We recommend that surgeons consider combined use of various types of anchoring when preoperative evaluation reveals narrow pedicles for screw placement.

Study Design. A retrospective review of 10 consecutive patients with a noninflammatory retro-odontoid pseudotumor. Objective. To examine the radiographic characteristics in patients with a retro-odontoid pseudotumor and to evaluate the efficacy of posterior fusion. Summary of Background Data. A retro-odontoid pseudotumor, a reactive fibrocartilaginous mass, is known to develop after chronic atlantoaxial instability; however, one-third of the reported cases showed no overt atlantoaxial instability. The pathomechanism for such "atypical" cases remains unclear, although altered cervical motion secondary to ossification of the anterior longitudinal ligament (OALL) or severe spondylosis has been implicated. Methods. We reviewed the charts and radiographs of 10 patients with a retro-odontoid pseudotumor who underwent surgery. Preoperative radiographs were evaluated for atlas-dens interval (ADI), presence of OALL, range of motion, and segmental motion adjacent to the atlantoaxial joint. Computed tomography was evaluated for degenerative changes of zygapophysial joints. Results. There were 6 men and 4 women. Atlantoaxial instability (ADI >4 mm) was observed in 2 patients. ADI was less than 3 mm in 5 patients. Frequent association of OALL (6 patients) and marked decrease in C2 to C7 range of motion (mean, 17.6; range, 3-36) were noted. Ankylosis of O-C1 was observed in 4 patients and C2 to C3 in 6. Severe degenerative change of C2 to C3 zygapophysial joint was observed in 4 patients. The patients underwent occipito-cervical fusion (9 patients) or direct removal of the pseudotumor (1 patient). Postoperative magnetic resonance imaging invariably demonstrated the mass regression. Conclusion. Retro-odontoid pseudotumors were not always associated with radiographic atlantoaxial instability. Our data indicate that extensive OALL and ankylosis of the adjacent segments are risk factors for the formation of the pseudotumor. Retro-odontoid pseudotumors may develop as an "adjacent segment disease" after altered biomechanics of the cervical spine, especially those in the adjacent segments. Posterior fusion was effective even in cases without radiographic atlantoaxial instability.

Study Design. Randomized controlled trial. Objective. To examine the effect of limaprost, an oral prostaglandin (PG) E1 derivative, on health-related quality of life (HRQOL) in patients with symptomatic lumbar spinal stenosis (LSS), compared to etodolac, a NSAID. Summary of Background Data. Limaprost, an oral PGE1 derivative, was developed in Japan to treat numerous ischemic symptoms of thromboangiitis obliterans (TAO) and LSS. Previous studies have demonstrated the effectiveness of limaprost in the symptoms in patients with LSS. However, the evidence for effect on patient-reported outcomes, such as patient's HRQOL or satisfaction, is limited. Methods. This study was conducted at 4 study sites in Japan. Briefly, inclusion criteria were: age between 50 and 85 years; presence of both neurogenic intermittent claudication (NIC) and cauda equina symptoms (at least presence of bilateral numbness in the lower limbs); and MRI-confirmed central stenosis with acquired degenerative LSS. Limaprost (15 mu g/d) or etodolac (400 mg/d) was administered for 8 weeks. The primary outcome was Short Form (SF)-36, and the secondary outcomes were the verbal rating scale of low back pain and leg numbness, walking distance, subjective improvement, and satisfaction. Results. A total of 79 participants were randomized (limaprost: etodolac = 39: 40). Thirteen participants withdrew from the study (limaprost: etodolac = 5: 8) and 66 completed the study (limaprost: etodolac = 34: 32). Comparisons showed that limaprost resulted in significantly greater improvements in the SF-36 subscales of physical functioning, role physical, bodily pain, vitality, and mental health. Limaprost was also significantly better than etodolac for leg numbness, NIC distance, and subjective improvement and satisfaction. In the subgroup analysis stratified by symptom severity, limaprost seemed more effective for milder symptoms. No serious adverse effects were reported in either treatment group. Conclusion. In this study, limaprost was found to be efficacious on most outcome measures, such as HRQOL, symptoms and subjective satisfaction, in LSS patents with cauda equina symptoms.

Objective. Type X collagen and runt-related transcription factor 2 (RUNX-2) are known to be important for chondrocyte hypertrophy during skeletal growth and repair and development of osteoarthritis (OA) in mice. Aiming at clinical application, this study was undertaken to investigate transcriptional regulation of human type X collagen by RUNX-2 in human cells. Methods. Localization of type X collagen and RUNX-2 was determined by immunohistochemistry, and their functional interaction was examined in cultured mouse chondrogenic ATDC-5 cells. Promoter activity of the human type X collagen gene (COL10A1) was examined in human HeLa, HuH7, and OUMS27 cells transfected with a luciferase gene containing a 4.5-kb promoter and fragments. Binding to RUNX-2 was examined by electrophoretic mobility shift assay and chromatin immunoprecipitation. Results. RUNX-2 and type X collagen were colocalized in mouse limb cartilage and bone fracture callus. Gain and loss of function of RUNX-2 revealed that RUNX-2 is essential for type X collagen expression and terminal differentiation of chondrocytes. Human COL10A1 promoter activity was enhanced by RUNX-2 alone and more potently by RUNX-2 in combination with the coactivator core-binding factor 0 in all 3 human cell lines examined. Deletion, mutagenesis, and tandem repeat analyses identified the core responsive element as the region between -89 and -60 bp (termed the hypertrophy box [HY box]), which showed specific binding to RUNX-2. Other putative RUNX-2 binding motifs in the human COL10A1 promoter did not respond to RUNX-2 in human cells. Conclusion. Our findings indicate that the HY box is the core element responsive to RUNX-2 in human COL10IA1 promoter. Studies on molecular networks related to RUNX-2 and the HY box will lead to treatments of skeletal growth retardation, bone fracture, and OA.

In this review, basic knowledge and recent innovation of surgical treatment for scoliosis will be described. Surgical treatment for scoliosis is indicated, in general, for the curve exceeding 45 or 50 degrees by the Cobb's method on the ground that: 1) Curves larger than 50 degrees progress even after skeletal maturity. 2) Curves of greater magnitude cause loss of pulmonary function, and much larger curves cause respiratory failure. 3) Larger the curve progress, more difficult to treat with surgery. Posterior fusion with instrumentation has been a standard of the surgical treatment for scoliosis. In modern instrumentation systems, more anchors are used to connect the rod and the spine, resulting in better correction and less frequent implant failures. Segmental pedicle screw constructs or hybrid constructs using pedicle screws, hooks, and wires are the trend of today. Anterior instrumentation surgery had been a choice of treatment for the thoracolumbar and lumbar scoliosis because better correction can be obtained with shorter fusion levels. Recently, superiority of anterior surgery for the thoracolumbar and lumbar scoliosis has been lost. Initial enthusiasm for anterior instrumentation for the thoracic curve using video assisted thoracoscopic surgery technique has faded out. Various attempts are being made with use of fusionless surgery. To control growth, epiphysiodesis on the convex side of the deformity with or without instrumentation is a technique to provide gradual progressive correction and to arrest the deterioration of the curves. To avoid fusion for skeletally immature children with spinal cord injury or myelodysplasia, vertebral wedge ostetomies are performed for the treatment of progressive paralytic scoliosis. For right thoracic curve with idiopathic scoliosis, multiple vertebral wedge osteotomies without fusion are performed. To provide correction and maintain it during the growing years while allowing spinal growth for early onset scoliosis, technique of instrumentation without fusion or with limited fusion using dual rod instrumentation has been developed. To increase the volume of the thorax in thoracic insufficiency syndrome associated with fused ribs and congenital scoliosis, vertical expandable prosthetic titanium ribs has been developed. © 2008 Maruyama and Takeshita licensee BioMed Central Ltd.

Study Design. Retrospective multi-institutional study Objective. To describe the surgical outcomes in patients with ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL) and to clarify factors related to the surgical outcomes. Summary of Background Data. Detailed analyses of surgical outcomes of T-OPLL have been difficult because of the rarity of this disease. Methods. The subjects were 154 patients with T-OPLL who were surgically treated at 34 institutions between 1998 and 2002. The surgical procedures were laminectomy in 36, laminoplasty in 51, anterior decompression via anterior approach in 25 and via posterior approach in 29, combined anterior and posterior fusion in 8, and sternum splitting approach in 5 patients. Instrumentation was conducted in 52 patients. Assessments were made on (1) The Japanese Orthopedic Association (JOA) scores (full score, 11 points), its recovery rates, (2) factors related to surgical results, and (3) complications and their consequences. Results. (1) The mean JOA score before surgery was 4.6 +/- 2.0 and, 7.1 +/- 2.5 after surgery. The mean recovery rate was 36.8% +/- 47.4%. (2) The recovery rate was 50% or higher in 72 patients (46.8%). Factors significantly related to this were location of the maximum ossification (T1-T4) (odds ratio, 2.43-4.17) and the use of instrumentation (odds ratio, 3.37). (3) The frequent complications were deterioration of myelopathy immediately after surgery in 18 (11.7%) and dural injury in 34 (22.1%) patients. Conclusion. The factors significantly associated with favorable surgical results were maximum ossification located at the upper thoracic spine and use of instrumentation. T-OPLL at the nonkyphotic upper thoracic spine can be treated by laminoplasty that is relatively a safe surgical procedure for neural elements. The use of instrumentation allows correction of kyphosis or prevention of progression of kyphosis, thereby, enhancing and maintaining decompression effect, and its use should be considered with posterior decompression.

Background. To establish a patient-oriented outcome measure for cervical myelopathy, a subcommittee of the Japanese Orthopaedic Association (JOA) developed a new scoring system to evaluate the overall clinical status of patients, which could be completed by patients themselves. The subcommittee completed three large-scale studies to select and modify questions derived from various preexisting outcome measures including Short Form-36, and then finalized and validated the questionnaire, which comprised 24 questions. Methods. The finalized questionnaire was administered to 369 patients with cervical myelopathy due to disc herniation, spondylosis, or ossification of posterior longitudinal ligament by randomly selected board-certified spine surgeons. Patients with different severities of myelopathy were included to insure accuracy and responsiveness of this questionnaire against patients' different neurological status. Results. Data of 236 patients were employed and were subjected to rigorous statistical analyses. There was no question that was difficult to answer and distribution of answers for each question was not concentrated to one choice, indicating the appropriateness of all 24 questions. Results of factor analysis suggested that the 24 questions could be divided into five different factors or functional domains. The factors were defined as follows: factor 1, lower extremity function; factor 2, quality of life; factor 3, cervical spine function; factor 4, bladder function; and factor 5, upper extremity function. Finally, equations that would yield scores for the five factors were assembled. The score to be used to represent the degree of patients' disability or status in each domain can be calculated by multiplying prefixed numbers of selected answers to questions by preassigned coefficients. Coefficients were defined to make the minimum score 0 and the maximum score 100. Conclusions. We have successfully established a questionnaire that is able to demonstrate the status of patients suffering cervical myelopathy from five different aspects represented by five intuitive numerical scores. The final issue to be confirmed is the responsiveness of this questionnaire to changes in patients' status after various surgical and nonsurgical treatments.