MRI-based interpretable radiomics nomogram for discrimination between Brucella spondylitis and Pyogenic spondylitis.

Background: Pyogenic spondylitis (PS) and Brucella spondylitis (BS) are commonly seen spinal infectious diseases. Both types can lead to vertebral destruction, kyphosis, and long-term neurological deficits if not promptly diagnosed and treated. Therefore, accurately diagnosis is crucial for personalized therapy. Distinguishing between PS and BS in everyday clinical settings is challenging due to the similarity of their clinical symptoms and imaging features. Hence, this study aims to evaluate the effectiveness of a radiomics nomogram using magnetic resonance imaging (MRI) to accurately differentiate between the two types of spondylitis. Methods: Clinical and MRI data from 133 patients (2017-2022) with pathologically confirmed PS and BS (68 and 65 patients, respectively) were collected. We have divided patients into training and testing cohorts. In order to develop a clinical diagnostic model, logistic regression was utilized to fit a conventional clinical model (M1). Radiomics features were extracted from sagittal fat-suppressed T2-weighted imaging (FS-T2WI) sequence. The radiomics features were preprocessed, including scaling using Z-score and undergoing univariate analysis to eliminate redundant features. Furthermore, the Least Absolute Shrinkage and Selection Operator (LASSO) was employed to develop a radiomics score (M2). A composite model (M3) was created by combining M1 and M2. Subsequently, calibration and decision curves were generated to evaluate the nomogram's performance in both training and testing groups. The diagnostic performance of each model and the indication was assessed using the receiver operating curve (ROC) with its area under the curve (AUC). Finally, we used the SHapley Additive exPlanations (SHAP) model explanations technique to interpret the model result. Results: We have finally selected 9 significant features from sagittal FS-T2WI sequences. In the differential diagnosis of PS and BS, the AUC values of M1, M2, and M3 in the testing set were 0.795, 0.859, and 0.868. The composite model exhibited a high degree of concurrence with the ideal outcomes, as evidenced by the calibration curves. The nomogram's possible clinical application values were indicated by the decision curve analysis. By using SHAP values to represent prediction outcomes, our model's prediction results are more understandable. Conclusions: The implementation of a nomogram that integrates MRI and clinical data has the potential to significantly enhance the accuracy of discriminating between PS and BS within clinical settings.

The Potential of a CT-Based Machine Learning Radiomics Analysis to Differentiate Brucella and Pyogenic Spondylitis.

Background: Pyogenic spondylitis (PS) and Brucella spondylitis (BS) are common spinal infections with similar manifestations, making their differentiation challenging. This study aimed to explore the potential of CT-based radiomics features combined with machine learning algorithms to differentiate PS from BS. Methods: This retrospective study involved the collection of clinical and radiological information from 138 patients diagnosed with either PS or BS in our hospital between January 2017 and December 2022, based on histopathology examination and/or germ isolations. The region of interest (ROI) was defined by two radiologists using a 3D Slicer open-source platform, utilizing blind analysis of sagittal CT images against histopathological examination results. PyRadiomics, a Python package, was utilized to extract ROI features. Several methods were performed to reduce the dimensionality of the extracted features. Machine learning algorithms were trained and evaluated using techniques like the area under the receiver operating characteristic curve (AUC; confusion matrix-related metrics, calibration plot, and decision curve analysis to assess their ability to differentiate PS from BS. Additionally, permutation feature importance (PFI; local interpretable model-agnostic explanations (LIME; and Shapley additive explanation (SHAP) techniques were utilized to gain insights into the interpretabilities of the models that are otherwise considered opaque black-boxes. Results: A total of 15 radiomics features were screened during the analysis. The AUC value and Brier score of best the model were 0.88 and 0.13, respectively. The calibration plot and decision curve analysis displayed higher clinical efficiency in the differential diagnosis. According to the interpretation results, the most impactful features on the model output were wavelet LHL small dependence low gray-level emphasis (GLDN). Conclusion: The CT-based radiomics models that we developed have proven to be useful in reliably differentiating between PS and BS at an early stage and can provide a reliable explanation for the classification results.

Development and validation of a novel nomogram to predict the risk of the prolonged postoperative length of stay for lumbar spinal stenosis patients.

BACKGROUND: Lumber spinal stenosis (LSS) is the increasingly reason for spine surgery for elder patients since China is facing the fastest-growing aging population. The aim of this research was to create a model to predict the probabilities of requiring a prolonged postoperative length of stay (PLOS) for lumbar spinal stenosis patients, minimizing the healthcare burden. METHODS: A total of 540 LSS patients were enrolled in this project. The outcome was a prolonged PLOS after spine surgery, defined as hospitalizations ≥ 75th percentile for PLOS, including the day of discharge. The least absolute shrinkage and selection operator (LASSO) was used to identify independent risk variables related to prolonged PLOS. Multivariable logistic regression analysis was utilized to generate a prediction model utilizing the variables employed in the LASSO approach. The receiver operating characteristic (ROC) curve's area under the curve (AUC) and the calibration curve's respective curves were used to further validate the model's calibration with predictability and discriminative capabilities. By using decision curve analysis, the resulting model's clinical effectiveness was assessed. RESULTS: Among 540 individuals, 344 had PLOS that was within the usual range of P75 (8 days), according to the interquartile range of PLOS, and 196 had PLOS that was above the normal range of P75 (prolonged PLOS). Four variables were incorporated into the predictive model, named: transfusion, operation duration, blood loss and involved spine segments. A great difference in clinical scores can be found between the two groups (P < 0.001). In the development set, the model's AUC for predicting prolonged PLOS was 0.812 (95% CI: 0.768-0.859), while in the validation set, it was 0.830 (95% CI: 0.753-0.881). The calibration plots for the probability showed coherence between the expected probability and the actual probability both in the development set and validation set respectively. When intervention was chosen at the potential threshold of 2%, analysis of the decision curve revealed that the model was more clinically effective. CONCLUSIONS: The individualized prediction nomogram incorporating five common clinical features for LSS patients undergoing surgery can be suitably used to smooth early identification and improve screening of patients at higher risk of prolonged PLOS and minimize health care.

Research progress of Chiari malformation type I and atlantoaxial instability / 中华骨科杂志

Chiari malformation (CM) is a group of congenital cerebellar tonsillar hernia malformations involving the craniocervical junction. Chiari malformation type I (CMI) is the most common in clinic, however its pathogenesis is still unclear, and there is no consensus on the surgical treatment standard of CMI. At present, the most widely accepted is the theory of posterior fossa incompatibility, so doctors at home and abroad use posterior fossa decompression (PFD) and posterior fossa compression with duraplasty (PFDD) as the gold standard for surgical treatment, and have their own experience and technical improvement. However, the volume of the posterior cranial fossa in some patients is no different from that in healthy people, and about 30% of the patients with CMI have poor results after posterior cranial fossa decompression. As a result, this operation cannot treat all patients with CMI. In recent years, with the development of imaging, the progress of diagnostic technology and the deepening of understanding of CM, some studies have shown that CMI may be related to atlantoaxial instability, and proposed that CMI is the secondary factor of atlantoaxial instability, and atlantoaxial fusion is the standard of surgical treatment, which has caused great controversy in academic circles. Different clinical research results of scholars support or oppose this theory: some studies have shown that the clinical symptom relief rate of patients with CMI treated with atlantoaxial fusion is 96.9%; another study showed that 70% of patients with CMI underwent atlantoaxial fusion had improved neurological function, but the overall postoperative effect was not satisfactory. In short, CMI is related to many diseases and its clinical manifestations are complex. Therefore, individualized management and treatment should be carried out in combination with the clinical manifestations and auxiliary examination results of patients.

Prediction of Sacral Screw Loosening after Lumbosacral Surgeries Involving Rigid Fixation of Sacral Bone Using Preoperative Computed Tomography Scans.

Objective: To find a preoperative computed tomography-based method to predict the incidence of sacral screw loosening and assist surgical planning. Methods: Surgically treated patients for degenerative lumbosacral disorders with rigid pedicle screw fixation of patients with L5-S1 vertebra in our center from January 2016 to January 2021 were retrospectively included in the current study. CT scan attenuation of the horizontal plane of the sacrum was measured with Hounsfield units (HU). Postoperative X-ray tests were used to diagnose screw loosening. The data was analyzed by independent sample t-tests, X 2 analysis, Pearson correlation analysis, and ROC curve analysis. Results: A total of 162 (114 male, 48 female, average age 63.7 ± 7.3 years) patients were included in the final analysis. Significant differences were found between the screw loosening group and nonloosening group concerning the HU value of the sacrum at the horizontal plane (P < 0.01). In ROC curve analysis, AUC was 0.674 (95% CI: 0.592-0.756). A cutoff of 200 HU provided 64.8% sensitivity and 62.4% specificity, and a cutoff of 150 HU provided 90.2% sensitivity. Conclusions: Analyzing 162 patients with at least 12 months of follow-up, we propose cutoff CT attenuation values of 200 HU and 150 HU to take moderate and radical measures of screw augmentation to prevent screw loosening in the sacral bone.

Development and validation of a diagnostic model for differentiating tuberculous spondylitis from brucellar spondylitis using machine learning: A retrospective cohort study.

Background: Tuberculous spondylitis (TS) and brucellar spondylitis (BS) are commonly observed in spinal infectious diseases, which are initially caused by bacteremia. BS is easily misdiagnosed as TS, especially in underdeveloped regions of northwestern China with less sensitive medical equipment. Nevertheless, a rapid and reliable diagnostic tool remains to be developed and a clinical diagnostic model to differentiate TS and BS using machine learning algorithms is of great significance. Methods: A total of 410 patients were included in this study. Independent factors to predict TS were selected by using the least absolute shrinkage and selection operator (LASSO) regression model, permutation feature importance, and multivariate logistic regression analysis. A TS risk prediction model was developed with six different machine learning algorithms. We used several metrics to evaluate the accuracy, calibration capability, and predictability of these models. The performance of the model with the best predictability was further verified with the area under the curve (AUC) of the receiver operating characteristic (ROC) curve and the calibration curve. The clinical performance of the final model was evaluated by decision curve analysis. Results: Six variables were incorporated in the final model, namely, pain severity, CRP, x-ray intervertebral disc height loss, x-ray endplate sclerosis, CT vertebral destruction, and MRI paravertebral abscess. The analysis of appraising six models revealed that the logistic regression model developed in the current study outperformed other methods in terms of sensitivity (0.88 ± 0.07) and accuracy (0.79 ± 0.07). The AUC of the logistic regression model predicting TS was 0.86 (95% CI, 0.81-0.90) in the training set and 0.86 (95% CI, 0.78-0.92) in the validation set. The decision curve analysis indicated that the logistic regression model displayed a higher clinical efficiency in the differential diagnosis. Conclusions: The logistic regression model developed in this study outperformed other methods. The logistic regression model demonstrated by a calculator exerts good discrimination and calibration capability and could be applicable in differentiating TS from BS in primary health care diagnosis.

Imaging study of simple Chiari malformation type I and atlantoaxial instability / 中华骨科杂志

Objective:To investigate the relationship between simple Chiari malformation type I (CMI) and atlantoaxial instability from the imaging point of view.Methods:A retrospective analysis were performed on 46 patients diagnosed with simple CMI from January 2014 to December 2020. Forty-six normal people matched for age and sex were selected as the normal control group, while 30 patients with atlantoaxial dislocation were selected as the dislocation group. The degree of atlantoaxial joint degeneration in each group was assessed according to Weishaupt degeneration grading; the atlantoaxial joint angulation angle was measured in the control group of patients with simple CMI; and the sagittal imaging parameters of cervical spine X-ray were measured, including C 0-C 1 Cobb angle, C 0-C 2 Cobb angle, C 1-C 2 Cobb angle, C 1-C 7 Cobb angle, C 2-C 7 Cobb angle, C 7 Slope, C 2 Tilt, spino cranial angle (SCA), and C 2-C 7 sagittal vertebral axis (SVA). All radiographic parameters were measured twice independently by two spine surgeons, and intraclass correlation coefficient (ICC) were determined to demonstrate intra- and inter-observer reliability. Results:ICC ranged between 0.842 and 0.974 in the current study, demonstrating "excellent" reliability of radiographic measurements. No significant difference was noted regarding age and the distribution of genders among the three groups. There were significant differences in the distribution of Weishaupt degeneration grading of atlantoaxial joints between simple CMI, normal and dislocation group ( H=53.68, P<0.001 on the left side; H=43.39, P<0.001 on the right side). There were significant differences in the degree of atlantoaxial joint degeneration between the normal group and dislocation group (left, Z=6.60, P<0.001; right, Z=6.29, P<0.001); There were significant differences in the degree of atlantoaxial joint degeneration between the normal group and simple CMI patients (left, Z=5.31, P<0.001; right, Z=4.13, P<0.001); There were significant differences in the degree of atlantoaxial joint degeneration between simple CMI and dislocation group (left, Z=3.20, P=0.001; right, Z=3.15, P=0.002). There were significant difference in the angulation angle of the atlantoaxial articular surface between the normal group and simple CMI patients (left, Z=3.32, P<0.001; right, Z=5.74, P<0.001). There were significant differences in C 0-C 1 Cobb angle ( t=2.41, P=0.018), C 1-C 7 Cobb angle ( t=2.88, P=0.005), C 2-C 7 Cobb angle ( t=3.29, P=0.001), and C 2-C 7 SVA ( t=2.87, P=0.005) between the normal group and simple CMI patients, but there was no significant difference in other parameters. Conclusion:The degree of atlantoaxial joint degeneration in patients with simple CMI is higher than that in normal people, the angulation angle is larger, and the cervical lordosis is larger, suggesting that there may be atlantoaxial joint instability. This study provides further evidence that Chiari malformation type I is associated with atlantoaxial instability.

Comparative study of native vertebral osteomyelitis and pyogenic postoperative and analysis of prognostic factors / 中华骨科杂志

Objective:To compare the microbiology, clinical characteristics and therapeutic efficacy of native suppurative spondylitis (NVO) and postoperative suppurative spondylitis (PVO), and analyze the factors affecting the prognosis.Methods:All patients with suppurative spondylitis were retrospectively analyzed from December 2010 to December 2019. A total of 46 patients were enrolled in this study. They were divided into two groups. There were 30 cases in NVO group, 18 males and 12 females; The age was 50.47±20.45 years, aged 15-73 years. There were 16 cases in PVO group, 10 males and 6 females; The age was 52.13±18.80 years, aged 14-73 years. In group NVO, 23 cases (76.7%) were in lumbar vertebrae, 5 cases (16.7%) in thoracic vertebrae and 2 cases (6.7%) in cervical vertebrae; in group PVO, 11 cases (68.8%) in lumbar vertebrae and 5 cases (31.2%) in thoracic vertebrae. Twenty-eight patients had neurological dysfunction before surgery. There were 25 cases of grade D (16 cases in group NVO and 9 cases in group PVO) and 3 cases of grade C (1 case in group NVO and 2 cases in group PVO), following the instructions of American Spinal Injury Association (ASIA) neurological function classification. All patients were given bed rest, nutritional support and antibiotic therapy; surgical treatment for patients with poor outcomes or aggravated symptoms. The patients were followed up after operation, the observation indexes included leukocyte count, erythrocyte sedimentation rate and C -reactive protein to evaluate the postoperative curative effect. The internal fixation device was evaluated for looseness and fracture by imaging examination. At the same time, the changes of visual analogue scale, ASIA neurological function grade were recorded to evaluate the clinical efficacy.Results:Two patients in NVO group were treated with antibiotics, and all the other patients successfully completed the operation. The diseased tissues were sent for pathological examination during the operation. The results showed that they were diagnosed as suppurative spondylitis. All patients were followed up for 12-24 months. Both groups were treated with intravenous and oral antibiotics, and the time of antibiotic treatment in group PVO was longer than that in group NVO without significant difference ( t=1.74, P=0.088). The leukocyte, C-reactive protein, erythrocyte sedimentation rate, visual analogue scale (VAS), were significantly improved in both groups at different time points after operation ( P<0.05) . There was no significant difference in leukocyte, C -reactive protein, erythrocyte sedimentation rate or VAS score between the two groups at the same time point after operation ( P>0.05). The neurological function of patients after operation was significantly improved compared with that before operation. In group NVO, 16 cases recovered from ASIA grade D to grade E, 1 case from grade C to grade D; 9 cases in group PVO recovered from grade D to grade E and 2 cases recovered from grade C to grade D. Till the last follow-up, 3 patients in group NVO recurred, the recurrence rate was 10% (3/30); 7 patients in group PVO recurred, the recurrence rate was 43.8%; the recurrence rate of group PVO was higher than that of group NVO, the difference was statistically significant (χ 2=5.14, P=0.023). Among 39 patients with spinal internal fixation, 12.8% (1 NVO, 4 PVO) had recurrent infection after internal fixation. Therefore, re-operation was performed to remove the internal fixator for infection control, patients recovered after conservative treatment such as immobilization and systemic anti-infection By univariate analysis, multiple vertebral involvement and abscess formation ( OR=11.00, P=0.006; OR=9.00, P=0.047) were significantly associated with pyogenic spondylitis recurrence; there was a tendency for pyogenic spondylitis recurrence among microbial infection ( OR=1.87, P=0.416), spinal prosthesis ( OR=7.20, P=0.074) and allogenic bone ( OR=1.78, P=0.478), yet not obvious. Multivariate analysis indicated that multiple vertebral involvement ( OR=10.49, P=0.038) was a risk factor for pyogenic spondylitis recurrence. Conclusion:The treatment of PVO is more challenging than NVO, especially in the cases of spinal implant infection. Although the antibiotic treatment time of PVO is longer than that of NVO, the recurrence rate of PVO is higher. Longer antibiotic therapy and, if necessary, surgical debridement or removal of implants are important approaches to successful treatment of PVO.

Unilateral or bilateral posterior fenestration debridement and bone graft fusion for the treatment of lumbosacral brucellosis spondylitis / 中华骨科杂志

Objective:To analyze the application and clinical efficacy of one-stage unilateral or bilateral fenestration, debridement, interbody fusion combined with posterior internal fixation for the treatment of lumbosacral brucellosis spondylitis.Methods:All patients with lumbosacral brucellosis spondylitis were retrospectively analyzed, who underwent fenestration, debridement, interbody fusion combined with posterior internal fixation from June 2013 to June 2019. A total of 48 patients were enrolled in this study. According to the surgical method, they were divided into two groups. Unilateral fenestration group: 27 cases of one-stage posterior unilateral fenestration, debridement, interbody fusion combined with posterior internal fixation were performed, 21 males and 6 females, aged 23-71 years; Bilateral fenestration group: 21 cases of one-stage posterior bilateral fenestration, debridement, interbody fusion combined with posterior internal fixation were performed, aged 26-58 years. There were 16 males and 5 females. The preoperative and postoperative clinical symptoms, neurological function, C-reactive protein, the surgery duration time, the blood loss, and erythrocyte sedimentation rate were observed. The internal fixation device was evaluated for looseness or fracture by imaging examination. The Bridwell classification criteria were used to evaluate the bone graft fusion. Postoperative complications were also assessed.Results:All patients completed the operation successfully, and the diseased tissues were sent for pathological examination during the operation, and all of them were diagnosed as brucellosis. All patients were followed up for 12-48 months (mean 23.7 ±6.3 months). C-reactive protein, erythrocyte sedimentation rate, Visual Analogue Scale (VAS), Oswestry Disability Index (ODI) and Japanese Orthopaedic Association Scores (JOA) were significantly improved in both groups at different time points after operation. There was no significant difference in the general condition before operation between the two groups ( P>0.05). The mean operation time and mean blood loss were 120.5±34.1 min and 214.4±150.2 ml, in the unilateral fenestration group; 187.1±30.3 min and 455.8±250.5 ml in the bilateral fenestration group; and the difference was significant ( t=8.123, t=2.962, P<0.05) . The postoperative lumbar and leg pain were significantly relieved. There was no significant difference in C-reactive protein, erythrocyte sedimentation rate, VAS, ODI and JOA scores between the two groups at the same time point. In the bilateral fenestration group, one patient developed incision infection half a month after the operation, who underwent debridement and drainage, and finally cured. There was no significant difference in the time of bone graft fusion between the two groups ( t=0.542, P>0.05). At the last follow-up, all the patients were completely fused. Conclusion:Unilateral or bilateral fenestration, debridement and bone graft fusion and internal fixation for the treatment of lumbosacral brucellosis spondylitis can achieve good clinical results, and the former has the advantages of short operation time and low cost.