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BackgroundCardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication following cardiac surgery. Early prediction of CSA-AKI is of great significance for improving patients' prognoses. The aim of this study is to systematically evaluate the predictive performance of machine learning models for CSA-AKI.MethodsCochrane Library, PubMed, EMBASE, and Web of Science were searched from inception to 18 March 2022. Risk of bias assessment was performed using PROBAST. Rsoftware (version 4.1.1) was used to calculate the accuracy and C-index of CSA-AKI prediction. The importance of CSA-AKI prediction was defined according to the frequency of related factors in the models.ResultsThere were 38 eligible studies included, with a total of 255,943 patients and 60 machine learning models. The models mainly included Logistic Regression (n = 34), Neural Net (n = 6), Support Vector Machine (n = 4), Random Forest (n = 6), Extreme Gradient Boosting (n = 3), Decision Tree (n = 3), Gradient Boosted Machine (n = 1), COX regression (n = 1), κNeural Net (n = 1), and Naïve Bayes (n = 1), of which 51 models with intact recording in the training set and 17 in the validating set. Variables with the highest predicting frequency included Logistic Regression, Neural Net, Support Vector Machine, and Random Forest. The C-index and accuracy wer 0.76 (0.740, 0.780) and 0.72 (0.70, 0.73), respectively, in the training set, and 0.79 (0.75, 0.83) and 0.73 (0.71, 0.74), respectively, in the test set.ConclusionThe machine learning-based model is effective for the early prediction of CSA-AKI. More machine learning methods based on noninvasive or minimally invasive predictive indicators are needed to improve the predictive performance and make accurate predictions of CSA-AKI. Logistic regression remains currently the most commonly applied model in CSA-AKI prediction, although it is not the one with the best performance. There are other models that would be more effective, such as NNET and XGBoost.Systematic review registrationhttps://www.crd.york.ac.uk/; review registration ID: CRD42022345259.

Xuedong Shi,1,* Yaosheng Liu,2,* Yunpeng Cui,1 Haifeng Qin,3 Shaoxing Yang,3 Mingxing Lei4 1Department of Orthopedic Surgery, Peking University First Hospital, Beijing, People’s Republic of China; 2Department of Orthopedic Surgery, The Fourth Medical Center of Chinese PLA General Hospital, Beijing, People’s Republic of China; 3Department of Pulmonary Neoplasms Internal Medicine, The Fifth Medical Center of the Chinese PLA General Hospital, Beijing, People’s Republic of China; 4Department of Orthopedic Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yaosheng LiuDepartment of Orthopedic Surgery, The Fourth Medical Center of Chinese PLA General Hospital, No. 8, Fengtaidongda Road, Beijing 100071, People’s Republic of ChinaTel/Fax +86-10-66947017Email 632763246@qq.comPurpose: The study aims to investigate and compare the efficacy and safety of intraoperative 125I implantation and postoperative irradiation after surgical decompression and stabilization in the treatment of patients with metastatic epidural spinal cord compression (MESCC).Methods: The study retrospectively enrolled 122 MESCC patients treated with surgical decompression and pedicle stabilization combined with 125I brachytherapy (the brachytherapy group) or postoperative radiotherapy (the irradiation group). Operation time, intraoperative blood loss, pain relief, postoperative ambulatory status, postoperative survival outcome, complications, and length of hospitalization were collected and compared between the two groups. Ten potential risk factors were analyzed for postoperative survival outcome.Results: No significant difference was found in baseline characteristics between the two groups (P> 0.05). Postoperative VAS score was significantly decreased, as compared with preoperative scores in both groups (P˂0.001). The VAS in the brachytherapy group was significantly lower than that in the irradiation group at postoperative 1 month, 3 months, and 6 months (P˂0.05). The postoperative ambulatory rates were 90.0% (54/60) in the brachytherapy group and 83.9% (52/62) in the irradiation group (P=0.32). The median overall survival time was similar between the two groups (7.43 months vs 7.27 months, P=0.37). Of all patients in the brachytherapy group, 25.0% (15/60) of patients suffered from complications, while 46.8% (29/62) of patients had complications in the irradiation group (P=0.0086). According to the multiple Cox regression, primary sites (P=0.038), ECOG performance status (P=0.014), and visceral metastases (P=0.0016) showed significance for postoperative survival outcome.Conclusion: Surgical decompression and spine stabilization combined with 125I brachytherapy is a relatively safe and useful method in MESCC patients.Keywords: metastatic epidural spinal cord compression, 125I brachytherapy, radiotherapy, surgical decompression and spine stabilization, prognosis

Yunpeng Cui,1,* Yuanxing Pan,1,* Mingxing Lei,2 Chuan Mi,1 Bing Wang,1 Xuedong Shi1 1Department of Orthopedic Surgery, Peking University First Hospital, Beijing, People’s Republic of China; 2Department of Orthopedic Surgery, Hainan Hospital of Chinese PLA General Hospital, Sanya, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xuedong ShiDepartment of Orthopedic Surgery, The Peking University First Hospital No. 8 Xishiku Street, Xicheng District Beijing 100032 People’s Republic of ChinaTel +86-010-83572211Email 172998774@qq.comPurpose: This study aims to develop an algorithm to predict cement injection volumes in patients with spine metastases treated with percutaneous vertebroplasty (PVP). Risk factors were also analyzed for intra-spinal canal cement leakages.Patients and Methods: A retrospective analysis of 584 vertebrae in 251 patients. Patients and vertebrae were divided into three groups based on grades of tumor invasion to the spinal cord. Patients with the complete posterior wall of vertebrae were classified into group A, patients without the complete posterior wall of vertebrae but with normal Dural sac were classified into group B, and patients with deformation of the Dural sac but without neurological symptom were classified into group C. We systematically reviewed demographic data, clinical parameters, radiology features, and cement leakages among the three groups. The multiple linear regressions were used to screen potential risk factors and develop the algorithm to predict injected cement volumes in vertebrae. Significant factors were included in the algorithm. Potential risk factors for intra-spinal canal cement leakage were analyzed using the multiple logistic regressions.Results: In the study, 17.1% (100/584) of vertebrae occurred cement leakages. Vertebrae in group C (28.6%, 8/28) had the highest cement leakage rate than patients in group A (14.4%, 61/424) and B (23.5%, 31/132) (P=0.014). Vertebrae in group C (14.3%, 4/28) were also more prone to intra-spinal canal leakages (P=0.003). The multiple logistic analysis showed that the Bilsky scale was significantly associated with intra-spinal canal cement leakages (P< 0.001). The multiple linear regression analysis showed that intercept (P< 0.001), treated vertebrae level (P< 0.001), cortical osteolytic destruction in posterior wall (P< 0.001), and Bilsky scale (P=0.014) were significant and those variables were included in the algorithm. The algorithm was Y=3.1627－0.8677×treated vertebrae level－0.6182×cortical osteolytic destruction in the posterior wall－0.2819×Bilsky scale.Conclusion: An algorithm is proposed and can be used to calculate cement injection volumes in spine metastases treated with PVP. This algorithm can facilitate surgical planning and guide cement injections. Bilsky scale is an independent risk factor for intra-spinal canal cement leakages. We do not recommend PVP treated in patients with a Bilsky scale of 2 and 3 mainly due to a high rate of intra-spinal canal cement leakages.Keywords: spinal metastases, percutaneous vertebroplasty, algorithm, intra-spinal canal leakages, risk factors

Many chemicalprofile agents have been widely adopted to control water content. Polymermicrosphere is a new potential profile control technology developed rapidly inrecent years. According to the diameter of reservoir rock throat, the polymermicrospheres matching the throat diameter are prepared by nano-micron materialsynthesis method. The mechanism of profile control is that the microspheres canmove freely in the porous media after entering the reservoir with injectedwater. The polymer microspheres accumulate in the throat to block up and causeresistance to the flow, so that the subsequent flow will turn around and flowaround. Because the microspheres have the certain degree of viscoelasticity,the microspheres will be elastic deformation as the plugging pressuredifference increases to a certain extent. Then the polymer microspherescontinue to migrate deeply through the throat, so as to achieve step-by-stepdeep profile control and flooding.In this article, divinylbenzene-co-acrylamide microspheres (DCAMs) with differentparticle size were firstly prepared by using dispersion polymerization. Thentheir physical properties such as chemical structure, micromorphology, particlesize and size distribution, swelling property and stability were reseached. Thecore displacement experiment under the simulated reservoir conditions was designedto analyze the recovery and profile modification performance of DCAMs.