Prognosis of cervical myelopathy based on diffusion tensor imaging with artificial intelligence methods.

Diffusion tensor imaging (DTI) has been proposed for the prognosis of cervical myelopathy (CM), but the manual analysis of DTI features is complicated and time consuming. This study evaluated the potential of artificial intelligence (AI) methods in the analysis of DTI for the prognosis of CM. Seventy-five patients who underwent surgical treatment for CM were recruited for DTI imaging and were divided into two groups based on their one-year follow-up recovery. The DTI features of fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity were extracted from DTI maps of all cervical levels. Conventional AI models using logistic regression (LR), k-nearest neighbors (KNN), and a radial basis function kernel support vector machine (RBF-SVM) were built using these DTI features. In addition, a deep learning model was applied to the DTI maps. Their performances were compared using 50 repeated 10-fold cross-validations. The accuracy of the classifications reached 74.2% ± 1.6% for LR, 85.6% ± 1.4% for KNN, 89.7% ± 1.6% for RBF-SVM, and 59.2% ± 3.8% for the deep leaning model. The RBF-SVM algorithm achieved the best accuracy, with sensitivity and specificity of 85.0% ± 3.4% and 92.4% ± 1.9% respectively. This finding indicates that AI methods are feasible and effective for DTI analysis for the prognosis of CM.

Robust spinal cord resting-state fMRI using independent component analysis-based nuisance regression noise reduction.

BACKGROUND: Physiological noise reduction plays a critical role in spinal cord (SC) resting-state fMRI (rsfMRI). PURPOSE: To reduce physiological noise and increase the robustness of SC rsfMRI by using an independent component analysis (ICA)-based nuisance regression (ICANR) method. STUDY TYPE: Retrospective. SUBJECTS: Ten healthy subjects (female/male = 4/6, age = 27 ± 3 years, range 24-34 years). FIELD STRENGTH/SEQUENCE: 3T/gradient-echo echo planar imaging (EPI). ASSESSMENT: We used three alternative methods (no regression [Nil], conventional region of interest [ROI]-based noise reduction method without ICA [ROI-based], and correction of structured noise using spatial independent component analysis [CORSICA]) to compare with the performance of ICANR. Reduction of the influence of physiological noise on the SC and the reproducibility of rsfMRI analysis after noise reduction were examined. The correlation coefficient (CC) was calculated to assess the influence of physiological noise. Reproducibility was calculated by intraclass correlation (ICC). STATISTICAL TESTS: Results from different methods were compared by one-way analysis of variance (ANOVA) with post-hoc analysis. RESULTS: No significant difference in cerebrospinal fluid (CSF) pulsation influence or tissue motion influence were found (P = 0.223 in CSF, P = 0.2461 in tissue motion) in the ROI-based (CSF: 0.122 ± 0.020; tissue motion: 0.112 ± 0.015), and Nil (CSF: 0.134 ± 0.026; tissue motion: 0.124 ± 0.019). CORSICA showed a significantly stronger influence of CSF pulsation and tissue motion (CSF: 0.166 ± 0.045, P = 0.048; tissue motion: 0.160 ± 0.032, P = 0.048) than Nil. ICANR showed a significantly weaker influence of CSF pulsation and tissue motion (CSF: 0.076 ± 0.007, P = 0.0003; tissue motion: 0.081 ± 0.014, P = 0.0182) than Nil. The ICC values in the Nil, ROI-based, CORSICA, and ICANR were 0.669, 0.645, 0.561, and 0.766, respectively. DATA CONCLUSION: ICANR more effectively reduced physiological noise from both tissue motion and CSF pulsation than three alternative methods. ICANR increases the robustness of SC rsfMRI in comparison with the other three methods. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:1421-1431.

Clinical and radiological outcomes of selective fusion for rotatory olisthesis in degenerative lumbar scoliosis: a retrospective cohort study.

STUDY DESIGN: Retrospective cohort study. PURPOSE: To investigate the long-term clinical and radiological outcomes of selective fusion for rotatory olisthesis (RO) in degenerative lumbar scoliosis (DLS). OVERVIEW OF LITERATURE: DLS is often associated with RO, and selective fusion of RO is a common surgical treatment option. However, the clinical and radiological outcomes remain controversial. METHODS: A cohort of 54 consecutive patients with DLS and RO was included in the study. All the included patients underwent selective RO fusion and at least 2 years of follow-up. They were divided into two groups: group 1 with a curve <30° and group 2 with a curve ≥30°. The clinical outcomes were evaluated by the Oswestry Disability Index (ODI) and Numerical Rating Scale. The radiological assessment included RO location, offset and subluxated-disc orientation, Cobb angle, and coronal as well as sagittal alignments. RESULTS: The offset value was greater in group 2 than in group 1 (13.4±4.7 mm vs. 9.3±3.5 mm, p<0.001). The subluxated disc was mainly oriented to the concave side in group 2 (15/21) but to the convex side in group 1 (20/33) (p =0.022). Group 2 had a higher rate of postoperative adjacent RO than group 1 (14/21 vs. 1/33, p<0.001). The ODI was comparable between both groups preoperatively but higher at the final follow-up in group 2 (34.9±9.5) than in group 1 (24.4±6.2). In the multiple logistic regression analysis, the thoracolumbar/lumbar curve was identified as the risk factor for postoperative adjacent RO (odds ratio, 1.400; p=0.007). The receiver operating characteristic analysis verified it with an area under the curve of 0.960 (p<0.001). CONCLUSIONS: The clinical and radiological outcomes were maintained well in group 1 but not in group 2. Selective RO fusion in DLS with a lumbar curve <30° is a rational option. However, it should be avoided in those with a lumbar curve >30° because of a higher complication rate and a worse clinical outcome at the final follow-up.

The Concept of Lamina-Pedicle Perpendicularity: Part 1. Lumbar Spine.

STUDY DESIGN: Retrospective radiographic study. PURPOSE: We hypothesized that the pedicle is almost perpendicular to the interlaminar line in the sagittal plane of the lumbar vertebrae. The current study aimed to define the lumbar lamina-pedicle inclination to verify the right-angle concept and to estimate the safety zones of sagittal inclination during pedicle screw insertion. To the best of our knowledge there are no previous similar studies. OVERVIEW OF LITERATURE: Based on our observations in different spinal disorders including deformities, we noted that following a sagittal (cranial-caudal) trajectory perpendicular to the interlaminar line joining the two adjacent vertebrae would work well in most of the vertebral levels. METHODS: This was a retrospective study on normal lumbar spine lateral radiographs of patients who presented with low back pain and were reviewed by two observers. Different inclination angles were constructed to estimate the safety zones of the pedicle screws' sagittal inclination. RESULTS: Radiographs of 30 consecutive patients, 25 females and five males, with a mean age of 39.43±11.18 years, were studied. The mean angle of the interlaminar line and the pedicle axis was almost orthogonal at all the levels, with a range of 89.16°-94.63°, which was not affected by the lumbar sagittal profile. The safety zones of the pedicle screws were measured, and they revealed a safe sagittal range of 19.73°-24.40° if the screw was inserted from the pedicle axis, 21.03°-22.59° if inserted from the most cephalic part, and 13.31°-17.03° if inserted from the most caudal part. CONCLUSIONS: Our results confirmed the perpendicularity of the interlaminar line with the pedicle axis in the lumbar spine at all the levels. The interlaminar line is a useful guide for pedicle screw sagittal inclination.

The Concept of Lamina-Pedicle Perpendicularity: Part 2: Thoracic Spine.

STUDY DESIGN: Retrospective radiographic study. PURPOSE: The hypothesis of this study was that the pedicle axis (PA) is almost perpendicular to the interlaminar line (ILL) in the sagittal plane of the thoracic vertebrae. The objective of the current study was to define the thoracic lamina-PA inclination in order to verify the right-angle concept and to estimate the safety zones for sagittal inclination during pedicle screw insertion. The authors, to the best of their knowledge, are unaware of previous similar studies. OVERVIEW OF LITERATURE: Based on the study's observations of different spinal disorders, including deformities, it was noted that following a sagittal cranial-caudal trajectory perpendicular to the ILL and joining the two adjacent thoracic vertebrae would work well at most vertebral levels. METHODS: This was a retrospective study on the computed tomography (CT) chest scans of patients with no spinal pathologies. The ILL-PA, superior and inferior safe angles of the pedicle screw trajectories, and the exit zone of the screw perpendicular to the ILL were reviewed by two observers via three-dimensional multiplanar reconstruction mode of the Horos DICOM software (https://horosproject.org/). RESULTS: The CT chest images of 30 consecutive patients (20 males and 10 females) with a mean age of 49.87±15.48 years (range, 24-74 years) were evaluated. The mean ILL-PA angle was almost orthogonal for all levels. This angle ranged between 86.21°±3.01° at D5 and 90.59°±2.72° at D10. The safety zones of the sagittal inclination of the pedicle screws were demonstrated. The results revealed that the least safe angle was when the screw was directed cranially along the middle part of the pedicle between 4.43°±0.75° at D8 and 6.94°±1.19° at D11. CONCLUSIONS: The results of this study confirmed the ILL-PA angle perpendicularity in the thoracic spine at all levels. The ILL is a useful guide for pedicle screw sagittal inclination.

Ten-year risk of osteoporotic fractures in postmenopausal Chinese women according to clinical risk factors and BMD T-scores: a prospective study.

UNLABELLED: Independent risk factors for osteoporotic fracture were identified for a Southern Chinese postmenopausal population. Clinical risk factor assessment with or without BMD measurement was shown to be an effective predictor of 10-yr risk of osteoporotic fracture and provides a more accessible tool for patient evaluation. INTRODUCTION: Asian-specific data on risk factors for osteoporosis remain sparse. However, risk factor assessment, in addition to BMD measurement, is increasingly recognized as a reliable predictor of absolute osteoporotic fracture risk. The purpose of this prospective study was to determine the specific independent risk factors for osteoporotic fracture and to predict the 10-yr risk of osteoporotic fracture in the postmenopausal Southern Chinese population. MATERIALS AND METHODS: A total of 1435 community-dwelling, postmenopausal, treatment-naive women were recruited. Baseline demographic characteristics and clinical risk factors were obtained, and BMD at the spine and hip was measured. Subjects were followed for outcomes of incident low trauma fracture. Ten-year risk of osteoporotic fracture was predicted from the risk factor assessment and BMD measurement by Cox proportional hazards models. RESULTS: The mean age of subjects was 63.4 +/- 8.3 yr. After 5.0 +/- 2.3 yr (range, 1.0-11.0 yr) of follow-up, 80 nontraumatic new fractures were reported during follow-up. Eight independent clinical risk factors identified at baseline were found to be significant predictors of osteoporotic fracture, with the most important being use of walking aids (RR, 4.2; 95% CI, 2.7-6.7; p < 0.001) and a history of fall (RR, 4.0; 95% CI, 2.5-6.2; p < 0.001). Other predictive factors included being homebound, calcium intake < 400 mg/d, age > 65 yr, history of fracture, and BMI < 19 kg/cm(2). Subjects with three to eight clinical risk factors had a predicted 10-year risk of osteoporotic fracture of 25%, which increased to 30% if they also had total hip BMD T-score

Amplitude of Low Frequency Fluctuation (ALFF) in the Cervical Spinal Cord with Stenosis: A Resting State fMRI Study.

Cervical spondylotic myelopathy (CSM) is a common spinal cord dysfunction disease with complex symptoms in clinical presentation. Resting state fMRI (rsfMRI) has been introduced to study the mechanism of neural development of CSM. However, most of those studies focused on intrinsic functional connectivity rather than intrinsic regional neural activity level which is also frequently analyzed in rsfMRI studies. Thus, this study aims to explore whether the level of neural activity changes on the myelopathic cervical cord and evaluate the possible relationship between this change and clinical symptoms through amplitude of low frequency fluctuation (ALFF). Eighteen CSM patients and twenty five healthy subjects participated in rsfMRI scanning. ALFF was investigated on each patient and subject. The results suggested that ALFF values were higher in the CSM patients at all cervical segments, compared to the healthy controls. The severity of myelopathy was associated with the increase of ALFF. This finding would enrich our understanding on the neural development mechanism of CSM.

A correlation study between in-brace correction, compliance to spinal orthosis and health-related quality of life of patients with Adolescent Idiopathic Scoliosis.

BACKGROUND: It has been proposed that in-brace correction is the best guideline for prediction of the results of brace treatment for patients with Adolescent Idiopathic Scoliosis (AIS). However, bracing may be a stressful experience for patients and bracing non-compliance could be psychologically related. The purpose of this study was to assess the correlation between brace compliance, in-brace correction and QoL of patients with AIS. METHODS: Fifty-five patients with a diagnosis of AIS were recruited. All were female and aged 10 years or above when a brace was prescribed, none had undergone prior treatment, and all had a Risser sign of 0-2 and a Cobb angle of 25-40°. The patients were examined in three consecutive visits with 4 to 6 months between each visit. The Chinese translated Trunk Appearance Perception Scale (TAPS), the Chinese translated Brace Questionnaires (BrQ) and the Chinese translated SRS-22 Questionnaires were used in the study. The in-brace Cobb angle, vertebral rotation and trunk listing were also measured. Patients' compliance, in-brace correction and patients' QoL were assessed. To identify the relationship among these three areas, logistic regression model and generalized linear model were used. RESULT: For the compliance measure, a significant difference (p = 0.008) was detected on TAPS mean score difference between Visit 1 and Visit 2 in the least compliant group (0-8 hours) and the most compliant group (17-23 hours). In addition, a significant difference (p = 0.000) was detected on BrQ mean score difference between Visit 2 and Visit 3 in the least compliant group (0-8 hours) and the most compliant group (17-23 hours). For the orthosis effectiveness measure, no significant difference was detected between the three groups of bracing hours (0-8 hours, 9-16 hours, 17-23 hours) on in-brace correction (below 40% and 40% or above). For the QoL measure, no significant difference was detected between the two different in-brace correction groups (below 40% and 40% or above) on QoL as reflected by the TAPS, BrQ and SRS-22r mean scores. CONCLUSION: The results showed a positive relationship between patients' brace wear compliance and patients' QoL. Poor compliance would cause a lower QoL.

Time-frequency feature of intraoperative somatosensory evoked potential signals.

The purpose of this paper is to investigate the time-frequency analysis of somatosensory evoked potentials (SEP) and its potential application to intraoperative spinal cord monitoring. In this study, SEP signals were recorded from 97 adolescent patients undergoing surgical correction of idiopathic scoliosis. The time-frequency distributions of SEP were observed during surgery by analysing averaged SEP signals with Short Time Fourier Transform (STFT). Main peak in time-frequency interpretation of SEP was measured in peak time, peak frequency and peak power. The changes of these parameters were compared with the changes of latency and amplitude. The results showed that changes in peak times and peak powers were found to correlate to the changes of latency and amplitude, respectively. However, the peak time showed more variability than the latency (p<0.01), while the peak power showed significantly lower variability than the amplitude (p<0.01). The peak frequency of SEP seems to be unchanged during surgery. Time-frequency analysis of SEP waveform gives stable and easily identifiable characteristics, and also shows higher specificity than amplitude and latency. Applying time-frequency analysis to SEP may improve the reliability of intraoperative spinal cord monitoring.

Selection of floating-point or fixed-point for adaptive noise canceller in somatosensory evoked potential measurement.

Adaptive noise canceller (ANC) has been used to improve signal to noise ratio (SNR) of somsatosensory evoked potential (SEP). In order to efficiently apply the ANC in hardware system, fixed-point algorithm based ANC can achieve fast, cost-efficient construction, and low-power consumption in FPGA design. However, it is still questionable whether the SNR improvement performance by fixed-point algorithm is as good as that by floating-point algorithm. This study is to compare the outputs of ANC by floating-point and fixed-point algorithm ANC when it was applied to SEP signals. The selection of step-size parameter (micro) was found different in fixed-point algorithm from floating-point algorithm. In this simulation study, the outputs of fixed-point ANC showed higher distortion from real SEP signals than that of floating-point ANC. However, the difference would be decreased with increasing micro value. In the optimal selection of micro, fixed-point ANC can get as good results as floating-point algorithm.

Treatment of stiff thoracic scoliosis by thoracoscopic anterior release combined with posterior instrumentation and fusion.

BACKGROUND: Thoracoscopic anterior release has been shown that it can effectively improve spinal flexibility in animal and human cadaveric studies, and has been advocated for use in patients with scoliosis. This prospective case series aims to investigate the improvement of the spinal flexibility and the effectiveness in deformity correction by anterior thoracoscopic release and posterior spinal fusion. METHODS: Eleven patients with stiff idiopathic thoracic scoliosis underwent anterior thoracoscopic release followed by posterior instrumentation. The average number of discs excised was five. Spinal flexibility was assessed by the fulcrum bending technique. Cobb angle before and after the anterior release was compared. RESULTS: The patients were followed for an average of 5.6 years (range 2.2 to 8.1 years). Fulcrum bending flexibility was increased from 39% before the thoracoscopic anterior spinal release to 54% after the release. The average Cobb angle before anterior release was 74 degrees on the standing radiograph and 45 degrees with the fulcrum-bending radiograph. This reduced to 34 degrees on the fulcrum-bending radiograph after the release, and highly corresponded to the 31 degrees measured at the post-operative standing radiograph. CONCLUSION: It was demonstrated in patients with stiff idiopathic thoracic scoliosis that thoracoscopic anterior spinal release can effectively improve the spinal flexibility and increase the correction of the spinal deformity.