Feasibility study on the clinical application of CT-based synthetic brain T1-weighted MRI: comparison with conventional T1-weighted MRI.

OBJECTIVES: This study aimed to examine the equivalence of computed tomography (CT)-based synthetic T1-weighted imaging (T1WI) to conventional T1WI for the quantitative assessment of brain morphology. MATERIALS AND METHODS: This prospective study examined 35 adult patients undergoing brain magnetic resonance imaging (MRI) and CT scans. An image synthesis method based on a deep learning model was used to generate synthetic T1WI (sT1WI) from CT data. Two senior radiologists used sT1WI and conventional T1WI on separate occasions to independently measure clinically relevant brain morphological parameters. The reliability and consistency between conventional and synthetic T1WI were assessed using statistical consistency checks, comprising intra-reader, inter-reader, and inter-method agreement. RESULTS: The intra-reader, inter-reader, and inter-method reliability and variability mostly exhibited the desired performance, except for several poor agreements due to measurement differences between the radiologists. All the measurements of sT1WI were equivalent to that of T1WI at 5% equivalent intervals. CONCLUSION: This study demonstrated the equivalence of CT-based sT1WI to conventional T1WI for quantitatively assessing brain morphology, thereby providing more information on imaging diagnosis with a single CT scan. CLINICAL RELEVANCE STATEMENT: Real-time synthesis of MR images from CT scans reduces the time required to acquire MR signals, improving the efficiency of the treatment planning system and providing benefits in the clinical diagnosis of patients with contraindications such as presence of metal implants or claustrophobia. KEY POINTS: • Deep learning-based image synthesis methods generate synthetic T1-weighted imaging from CT scans. • The equivalence of synthetic T1-weighted imaging and conventional MRI for quantitative brain assessment was investigated. • Synthetic T1-weighted imaging can provide more information per scan and be used in preoperative diagnosis and radiotherapy.

Comparison of the prognostic factors of total en bloc spondylectomy and total piecemeal spondylectomy in patients with Enneking stage III giant cell tumor in the thoracic and lumbar spine.

PURPOSE: To compare total en bloc spondylectomy with marginal margins against piecemeal spondylectomy with intralesional margins in the surgical treatment of Enneking stage III spinal giant cell tumor (GCT) in terms of local recurrence. METHODS: A retrospective survival analysis of patients with Enneking stage III GCT who underwent TES with marginal margins or total piecemeal spondylectomy with intralesional margins was performed between January 2006 and April 2020. Local recurrence-free survival (LRFS) was the time between the date of surgery and recurrence. Factors with p-values < 0.05 in the univariate analysis were included in the multivariate analysis using proportional hazard analysis. RESULTS: Sixty patients (25 men and 35 women) with a mean age of 35.6 (range 11-71) years were included. The mean follow-up duration was 93 (range 24-198) months. Two patients were lost to follow-up 6 and 14 years after the procedure. Over a 10-year period, the recurrence rate was 13.3%. The 2-, 5-, and 10-year LRFS rates were 95%, 88%, and 78%, respectively. Univariate analysis identified total piecemeal spondylectomy and no adjuvant radiotherapy as prognostic factors for LRFS. Multivariate Cox-regression models showed a significant association between local recurrence and total piecemeal spondylectomy and no adjuvant radiotherapy. CONCLUSION: TES with marginal margins is better than total piecemeal spondylectomy with intralesional margins owing to its lower postoperative recurrence rate. Adjuvant radiotherapy should be administered to reduce postoperative recurrence rates.

Complications and prognosis of primary thoracic and lumbar giant cell tumors treated by total tumor resection.

BACKGROUND: Spinal giant cell tumor (SGCT) is a relatively rare primary tumor. En bloc resection is the preferred surgical procedure for it due to its aggressiveness, meanwhile leading to more complications. We reported the characteristics of perioperative complications and local control of total tumor resection including en bloc resection and piecemeal resection for primary thoracic and lumbar spinal giant cell tumors in a single center over 10 years. METHODS: This is a retrospective cross-sectional and cohort study. Forty-one consecutive patients with SGCTs who underwent total tumor resection from 2010 to 2020 at our institution and were followed up for at least 24 months were reviewed. Surgery data, complication characteristics and local tumor control were collected and compared by different surgical procedure. RESULTS: Forty-one patients were included, consisting of 18 males and 23 females, with a mean age of 34.2 years. Thirty-one had thoracic vertebra lesions, and 10 had lumbar vertebra lesions. Thirty-five patients were primary cases, and 6 patients were recurrent cases. Eighteen patients were treated by total en bloc spondylectomy (TES), 12 patients underwent en bloc resection according to WBB surgical system, and 11 patients underwent piecemeal resection. The average surgical time was 498 min, and the mean estimated blood loss was 2145 ml. A total of 58 complications were recorded, and 30 patients (73.2%) had at least one perioperative complication. All patients were followed up after surgery for at least 2 years. A total of 6 cases had postoperative internal fixation failure, and 4 cases presented local tumor recurrence (9.8%). CONCLUSIONS: Although the surgical technique is difficult and accompanied by a high rate of perioperative complications, en bloc resection can achieve favorable local control in SGCT. When it is too difficult to complete en bloc resection, thoroughly piecemeal resection without residual is also acceptable, given the relatively low recurrence rate.

Postoperative alterations of sagittal cervical alignment and risk factors for cervical kyphosis in 124 Lenke 1 adolescent idiopathic scoliosis patients.

BACKGROUND: This study aims to analyze postoperative changes of cervical sagittal curvature and to identify independent risk factors for cervical kyphosis in Lenke type 1 adolescent idiopathic scoliosis (AIS) patients. METHODS: A total of 124 AIS patients who received all-pedicle-screw instrumentation were enrolled. All patients were followed up for at least 2 years. The following parameters were measured preoperatively, immediately after the operation, and at the last follow-up: pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), global thoracic kyphosis (GTK), proximal thoracic kyphosis (PrTK), T1-slope, cervical lordosis (CL), McGregor slope (McGS), sagittal vertical axis (SVA), C2-7 SVA (cSVA), and main thoracic angle (MTA). Statistical analysis was performed to evaluate postoperative alterations of and correlations between the parameters and to identify risk factors for cervical kyphosis. Statistical significance was set at P < 0.05. RESULTS: After the operation, PrTK and T1-slope significantly increased (3.01 ± 11.46, 3.8 ± 10.76, respectively), cervical lordosis improved with an insignificant increase (- 2.11 ± 13.47, P = 0.154), and MTA, SS, and LL decreased significantly (- 33.68 ± 15.35, - 2.98 ± 8.41, 2.82 ± 9.92, respectively). Intergroup comparison and logistic regression revealed that preoperative CK > 2.35° and immediate postoperative GTK < 27.15° were independent risk factors for final cervical kyphosis, and △T1-slope < 4.8° for a kyphotic trend. CONCLUSIONS: Postoperative restoration of thoracic kyphosis, especially proximal thoracic kyphosis, and T1-slope play a central role in cervical sagittal compensation. Preoperative CK, postoperative small GTK, and insufficient △T1-slope are all independent risk factors for cervical decompensation.

Surgical complications of extraspinal tumors in the cervical spine: a report of 110 cases and literature review.

PURPOSE: To assess the safety of surgical intervention for extraspinal tumors in the cervical spine. METHODS: 110 consecutive patients were enrolled and followed-up at least 12 months or until death. The complication rates and risk factors were documented and analyzed. RESULTS: The quality of life in the surviving patients was significantly improved. The overall local recurrence rate was 17.3%. Twenty percent of patients developed distant metastasis. The perioperative mortality rate (30 days after surgery) was 0.9%. The complication related mortality was 1.8%. The rates of overall complication and major complication were 41.8% and 20.9%, respectively. The independent predictors for overall complications were Karnofsky score <60, multisegmental resection, and operation time >3 h. The independent predictors of major complications were comorbidity, tumor location at C1-C2, and combined approach. CONCLUSIONS: Surgery for cervical spine tumor could improve the quality of life, though it might be accompanied with high morbidity and mortality. It is a highly demanding procedure; however, it can be performed to an acceptable degree of safety.

Prognostic Factors in Surgical Patients with Chordomas of the Cervical Spine: A Study of 52 Cases from a Single Institution.

BACKGROUND: The recurrence rate of cervical chordomas is high, and hence it is important to discern the prognostic factors for local relapse and overall survival (OS). METHODS: A retrospective review of 52 patients with cervical chordoma operated in our institution from January 1999 to March 2015 was performed. The association of clinicopathologic characteristics with local relapse-free survival (LRFS) and OS was analyzed. Univariate analysis was performed to determine whether tumor characteristics and types of therapy affected prognosis, and a multivariate Cox proportional hazard model was developed to further investigate local recurrence and mortality. RESULTS: Mean follow-up time was 50 months. The cumulative 5- and 10-year LRFS was 35 and 0%, respectively, while the cumulative 5- and 10-year OS was 69 and 53%, respectively. The univariate analysis identified contiguous segments involved, intralesional surgical margin at primary surgery, primary surgery in local hospital, incisional biopsy, and without adjuvant radiotherapy as negative prognostic factors for LRFS, whereas for OS, only tumor location in the upper cervical spine was statistically significant. In the multivariate analysis, contiguous vertebral segments involved, intralesional surgical margins, and incisional biopsy were identified as negative prognostic factors for LRFS, whereas for OS, again only tumor location in the upper cervical spine was statistically significant. CONCLUSIONS: Contiguous vertebral segments involved, intralesional surgical margin, without adjuvant radiotherapy, and incisional biopsy significantly increase local recurrence, while tumor location in the upper cervical spine significantly increases tumor-related mortality. Thus, computed tomography-guided fine-needle aspiration biopsy and total spondylectomy with marginal excision may improve survival of patients with cervical chordoma.

Differences in calcification and osteogenic potential of herniated discs according to the severity of degeneration based on Pfirrmann grade: a cross-sectional study.

BACKGROUND: Herniated discs may exhibit calcification, and calcified discs may complicate surgical treatment. However, the osteogenic potential and expression of osteogenic markers in degenerative discs of different degenerative grades are still unclear. Our purposes are to study the differences in calcification rate and osteogenic potential of herniated discs according to different degenerative grades. METHODS: Fifty-eight lumbar intervertebral discs were removed from 41 patients. After grading according to the Pfirrmann scale, calcification was analyzed by micro computed tomography (µ-CT), and expression of osteogenic markers was analyzed by immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR). Data from µ-CT scans were compared with the Kruskal-Wallis test. The Mann-Whitney test was applied to compare data between any two groups. Differences in osteogenic mRNA expression in different regions of the removed discs (posterior vs. anterior) were analyzed by paired t tests. Differences in the posterior portion of removed discs of different Pfirrmann grades were analyzed by one-way analysis of variance (ANOVA), and comparisons of data between discs of any two grades were completed with least significant difference (LSD) tests. RESULTS: Significant differences in calcification according to µ-CT scanning were observed between discs of different degenerative grades. Nearly half of the discs of Pfirrmann grade V showed the highest degree of calcification compared to Pfirrman grade II discs. Bone morphogenetic protein (BMP)-2, Osterix, and Osteocalcin were detected histologically in discs of Pfirrmann grades III-V. Alkaline phosphatase (ALP) expression was observed in discs showing evidence of calcification. The qPCR analysis showed that BMP-2, Osterix, and Osteocalcin were expressed in most degenerated discs. We also observed greater expression of these osteogenic markers in the posterior portion of removed discs than in the anterior portion. CONCLUSIONS: The osteogenic potential of degenerated intervertebral discs appears to increase with the severity of degeneration and to be greater in the tissue near the spinal canal than in tissue in the inner portion of the disc.

Primary tumors of the spine: a review of clinical features in 438 patients.

Primary spinal tumors are rare. Current knowledge on this subject is therefore limited due to the lack of study with large cohort. This study is prompted to share our data on clinical profiles of primary spinal tumors collected from a large series of patients. Clinical manifestations of 438 consecutive patients were summarized retrospectively with statistical analysis. In the spine, benign tumor is more common than malignant. The most prevalent tumor is giant cell tumor. Tumors predominately occur between the age of 18 and 59 and the risk of malignancy increases significantly after 40. Main symptoms include local pain and neurological symptoms with frequent occurrence of neurological deficits and pathological fracture. Pain is caused by tumor expansion, pathological fracture and nerve entrapment. Occurrence of neurological deficits is significantly related to patent's age and the region of involvement. Giant cell tumor is associated with the highest incidence of neurological fracture with significance. Duration of symptom is 6 months on average. The most affected region is the cervical spine, followed by the thoracic and the lumbar spine. Tumors at the sacrum and coccyx are more likely to be malignant. Malignant tumors have significantly higher incidence of involvement at multiple levels than benign tumors. This study contributes by improving our understanding of this rare clinical entity.

[Efficacy and survival rate analysis of lung cancer with spinal metastases].

OBJECTIVE: To explore the efficacy of surgical treatment and the prognosis factors of spinal metastases secondary to lung cancer. METHODS: From April 2005 to April 2012, 35 patients diagnosed as spinal metastases secondary to lung cancer were reviewed retrospectively. All the patients were divided into surgical group and conservative group. Severity of pain, neurological status and quality of life preoperatively and postoperatively were compared; and the relevance between their survival time and radiotherapy, medical therapy (chemotherapy and/or targeted therapy), surgical treatment, quality of life, and neurological status were evaluated. RESULTS: Of all the patients, 28 (80%, 28/35) had been followed up. The surgical group contained 22 cases and the conservative group 6. The severity of pain and quality of life improved significantly in the surgical group. The median of visual analog scale for pain reduced from 7 points to 3 points (z = 4.143, P < 0.05); the median of Karnorfsky performance score increased from 50 points to 60 points (z = 3.825, P < 0.05). For the 13 patients in the surgical group who had neurological deterioration, the improvement of Frankel grade was statistically different (z = 2.530, P < 0.05). The survival analysis indicated that medical therapy had significant association with longer survival (P = 0.001). However, surgery, radiotherapy, neurological status and quality of life had no direct relations with survival time. CONCLUSION: Surgical treatment for spinal metastases secondary to lung cancer can effectively relieve the pain, improve the quality of life and neurological status. The survival time is largely influenced by medical therapy.

Radial Undersampled MRI Reconstruction Using Deep Learning With Mutual Constraints Between Real and Imaginary Components of K-Space.

The deep learning method is an efficient solution for improving the quality of undersampled magnetic resonance (MR) image reconstruction while reducing lengthy data acquisition. Most deep learning methods neglect the mutual constraints between the real and imaginary components of complex-valued k-space data. In this paper, a new complex-valued convolutional neural network, namely, Dense-U-Dense Net (DUD-Net), is proposed to interpolate the undersampled k-space data and reconstruct MR images. The proposed network comprises dense layers, U-Net, and other dense layers in sequence. The dense layers are used to simulate the mutual constraints between real and imaginary components, and U-Net performs feature sparsity and interpolation estimation for k-space data. Two MRI datasets were used to evaluate the proposed method: brain magnitude-only MR images and knee complex-valued k-space data. Several operations were conducted for data preprocessing. First, the complex-valued MR images were synthesized by phase modulation on magnitude-only images. Second, a radial trajectory based on the golden angle was used for k-space undersampling, whereby a reversible normalization method was proposed to balance the distribution of positive and negative values in k-space data. The optimal performance of DUD-Net was demonstrated based on a quantitative evaluation of inter-method and intra-method comparisons. When compared with other methods, significant improvements were achieved, PSNRs were increased by 10.78 and 5.74dB, whereas RMSEs were decreased by 71.53% and 30.31% for magnitude and phase image, respectively. It is concluded that DUD-Net significantly improves the performance of MR image reconstruction.

Posterior thoracic antedisplacement and fusion surgery for a special type of ossification of the posterior longitudinal ligament in the thoracic spine: indications and preliminary clinical results of 2-year follow-up.

OBJECTIVES: To describe a novel technique, posterior thoracic antedisplacement and fusion (PTAF), for a special type of ossification of the posterior longitudinal ligament in the thoracic spine (T-OPLL), and to evaluate its safety and efficacy. METHODS: From July to December 2020, five consecutive patients with beak-type T-OPLL located at the thoracic vertebral body (VB) level underwent PTAF surgery. Their demographic data, radiological parameters, perioperative complications, and surgery-related findings were recorded and analyzed. The surgical outcomes were assessed using a modified Japanese Orthopedic Association (mJOA) scale, and the recovery rate (RR) was calculated using the Hirabayashi's method. RESULTS: All patients were followed up for at least two years. The mean thickness of OPLL was 9.4 ± 1.0 mm, and the OPLL spinal canal occupying ratio was 67.7% ± 8.5%. Postoperatively, the mean antedisplacement distance of OPLL was 8.1 ± 1.8 mm, and the average shortened distance of the spinal column was 6.0 ± 1.13 mm. The mean operation time and blood loss were 158.2 ± 26.3 min and 460 ± 89.4 mL, respectively. Perioperative complications were cerebrospinal fluid leakage and instrument failure, 2 cases each. The mean mJOA score was increased from 3.6 ± 2.9 before surgery to 9.4 ± 3.0 at the last follow-up, and the average RR was 84.2 ± 30.5%. CONCLUSION: The preliminary clinical outcomes indicate that PTAF is a safe and effective method for the treatment of beak-type T-OPLL, which has its apex located at the VB level and has a high spinal canal occupation ratio.

[Medical therapy of polyostotic fibrous dysplasia of the spinal column].

OBJECTIVE: To discuss treatments of spinal polyostotic fibrous dysplasia (PFD) and their clinical outcomes. METHODS: A group of spinal PFD patients treated in orthopaedic department of Peking University Third Hospital from January 2005 to December 2010 was retrospectively reviewed. There were 3 males and 1 female. The age was 53, 17, 32, 38 years, respectively. Two cases underwent preoperative CT-guided biopsy and the other two had previous pathologic results. All the patients complained localized pain and VAS (visual analogue scale) ranged from 3 to 5. All the cases had pathologic fractures and 3 cases had neurological impairment. The surgical procedures for each patient were as follows: lesion resection combined with cervicothoracic fixation and fusion; reduction combined with occipitocervical fixation and fusion; vertebroplasty (VP); VP combined with posterior decompression and fixation. RESULTS: Fibrous dysplasia in each patient was confirmed by postoperative pathological examination. The operation time was 420, 150, 120, 300 minutes and blood loss was 3 400, 500, 200, 2 000 mL. The follow-up period was 84, 24, 34, 12 months. The primary symptoms were fully relieved without any surgery related complication. There was no symptom recurrence or lesion progress during the follow-up. No signs of radiological improvements (filling of lytic lesion, cortical thickening, or both) were detected. CONCLUSION: Spinal PFD is a rare disease and mostly affects adults. Conventional excision therapy is an effective and reliable treatment for spinal PFD, but vertebroplasty is less invasive. VP alone might be more appropriate for patients complaining only pain symptoms and/or with pathologic fractures. VP combined with limited decompression and stabilization may be more suitable for patients with neurological deficits.

The automatic evaluation of steno-occlusive changes in time-of-flight magnetic resonance angiography of moyamoya patients using a 3D coordinate attention residual network.

Background: Moyamoya disease (MMD) is a rare cerebrovascular occlusive disease with progressive stenosis of the terminal portion of internal cerebral artery (ICA) and its main branches, which can cause complications, such as high risks of disability and increased mortality. Accurate and timely diagnosis may be difficult for physicians who are unfamiliar to MMD. Therefore, this study aims to achieve a preoperative deep-learning-based evaluation of MMD by detecting steno-occlusive changes in the middle cerebral artery or distal ICA areas. Methods: A fine-tuned deep learning model was developed using a three-dimensional (3D) coordinate attention residual network (3D CA-ResNet). This study enrolled 50 preoperative patients with MMD and 50 controls, and the corresponding time of flight magnetic resonance angiography (TOF-MRA) imaging data were acquired. The 3D CA-ResNet was trained based on sub-volumes and tested using patch-based and subject-based methods. The performance of the 3D CA-ResNet, as evaluated by the area under the curve (AUC) of receiving-operator characteristic, was compared with that of three other conventional 3D networks. Results: With the resulting network, the patch-based test achieved an AUC value of 0.94 for the 3D CA-ResNet in 480 patches from 10 test patients and 10 test controls, which is significantly higher than the results of the others. The 3D CA-ResNet correctly classified the MMD patients and normal healthy controls, and the vascular lesion distribution in subjects with the disease was investigated by generating a stenosis probability map and 3D vascular structure segmentation. Conclusions: The results demonstrated the reliability of the proposed 3D CA-ResNet in detecting stenotic areas on TOF-MRA imaging, and it outperformed three other models in identifying vascular steno-occlusive changes in patients with MMD.

Risk Factors and Three Radiological Predictor Models for the Progression of Proximal Junctional Kyphosis in Adult Degenerative Scoliosis Following Posterior Corrective Surgery: 113 Cases With 2-years Minimum Follow-Up.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To identify risk factors and predictive models for proximal junctional kyphosis (PJK) in a long-term follow-up of patients with adult degenerative scoliosis (ADS) following posterior corrective surgeries. MATERIALS AND METHODS: A consecutive 113 ADS patients undergoing posterior corrective surgery between January 2008 and April 2019 with minimum 2-year follow-up were included. All patients underwent preoperative, postoperative, and final follow-up by X-ray imaging. Multivariate logistic analysis was performed on various risk factors and radiological predictor models. RESULTS: PJK was identified radiographically in 46.9% of patients. Potential risk factors for PJK included postoperative thoracic kyphosis (TK) (P < .05), final follow-up Pelvic Tilt (PT) (P < .05), PT changes at final follow-up (P < .05), age over 55 years old at the surgery (P < .05), theoretical thoracic kyphosis-actual thoracic kyphosis mismatch (TK mismatch) (P < .05) and theoretical lumbar lordosis-acutal lumbar lordosis mismatch (LL mismatch) (P < .05). As for the predictive models, PJK was predictive by the following indicators: preoperative global sagittal alignment ≥45° (Model 1), postoperative pelvic incidence-lumbar lordosis mismatch (PI-LL)≤10° and postoperative PI-LL overcorrection (Model 2), and TK+LL≥0° (Model 3) (P < .05). Postoperative TK mismatch (OR = 1.064) was independent as risk factors for PJK, with the cut-off values respectively set at -28.56° to predict occurrence of PJK. CONCLUSION: The risk of radiographic PJK increases with an age over 55 years old and higher postoperative TK. In addition, postoperative TK mismatch is an independent risk factor for developing PJK. All three predictive models could effectively indicate the occurrence of PJK.

Computer-Aided Diagnosis of Spinal Tuberculosis From CT Images Based on Deep Learning With Multimodal Feature Fusion.

Background: Spinal tuberculosis (TB) has the highest incidence in remote plateau areas, particularly in Tibet, China, due to inadequate local healthcare services, which not only facilitates the transmission of TB bacteria but also increases the burden on grassroots hospitals. Computer-aided diagnosis (CAD) is urgently required to improve the efficiency of clinical diagnosis of TB using computed tomography (CT) images. However, classical machine learning with handcrafted features generally has low accuracy, and deep learning with self-extracting features relies heavily on the size of medical datasets. Therefore, CAD, which effectively fuses multimodal features, is an alternative solution for spinal TB detection. Methods: A new deep learning method is proposed that fuses four elaborate image features, specifically three handcrafted features and one convolutional neural network (CNN) feature. Spinal TB CT images were collected from 197 patients with spinal TB, from 2013 to 2020, in the People's Hospital of Tibet Autonomous Region, China; 3,000 effective lumbar spine CT images were randomly screened to our dataset, from which two sets of 1,500 images each were classified as tuberculosis (positive) and health (negative). In addition, virtual data augmentation is proposed to enlarge the handcrafted features of the TB dataset. Essentially, the proposed multimodal feature fusion CNN consists of four main sections: matching network, backbone (ResNet-18/50, VGG-11/16, DenseNet-121/161), fallen network, and gated information fusion network. Detailed performance analyses were conducted based on the multimodal features, proposed augmentation, model stability, and model-focused heatmap. Results: Experimental results showed that the proposed model with VGG-11 and virtual data augmentation exhibited optimal performance in terms of accuracy, specificity, sensitivity, and area under curve. In addition, an inverse relationship existed between the model size and test accuracy. The model-focused heatmap also shifted from the irrelevant region to the bone destruction caused by TB. Conclusion: The proposed augmentation effectively simulated the real data distribution in the feature space. More importantly, all the evaluation metrics and analyses demonstrated that the proposed deep learning model exhibits efficient feature fusion for multimodal features. Our study provides a profound insight into the preliminary auxiliary diagnosis of spinal TB from CT images applicable to the Tibetan area.

Medium to long term follow-up of survival and quality of life in patients with primary tumors of the cervical spine: Experience From a large single center.

Objectives: To evaluate the survival and medium to long term health-related quality of life (HRQoL) of patients with primary cervical spinal tumors in a cross-sectional study and to identify any significant associations with demographic or clinical characteristics. Methods: Patients diagnosed with primary cervical spinal tumors were retrospectively enrolled and their clinical, radiologic, and follow-up data (specifically the EQ-5D questionnaire) were collected. Univariate and multivariate Cox time-dependent regression analyses were performed to examine the significance of certain variables on overall survival. Univariate and multivariate logistic regression analyses were conducted to identify variables significant for overall HRQoL and each dimension of the EQ-5D. Results: A total of 341 patients were enrolled in the study with a mean follow-up of 70 months. The diagnosis was benign in 246 cases, malignant in 84, and unconfirmed in 11. The 5-year overall survival rate was 86% and the 10-year overall survival rate was 65%. Multivariate analysis suggested that surgical treatment (P = 0.002, hazard ratio [HR] = 0.431, 95% CI. [0.254, 0.729]), benign and malignant tumors [P < 0.001, HR = 2.788, 95% CI. (1.721, 4.516)], tumor and surrounding normal tissue boundary [P = 0.010, HR = 1.950, 95% CI. (1.171, 3.249)], and spinal instability [P = 0.031, HR = 1.731, 95% CI. (1.051, 2.851)] still had significant effects on survival. Conclusions: In this cross-sectional study, we evaluated the survival period and medium and long-term health-related quality of life of patients with primary tumors of the cervical spine, and analyzed the significant related factors of tumor clinical characteristics. Surgery, myelopathy, malignancy, spinal pain relieved by lying down or supine position, and tumor infiltration on MRI were significant predictors for overall survival. Enneking stage and age were significant predictors for HRQoL.

Effect of Tungsten Species on Selective Hydrogenolysis of Glycerol to 1,3-Propanediol.

Glycerol, as the major byproduct of biodiesel industry, is a cheap and green chemical feedstock. Following the expanded production of biodiesel, the oversupply of glycerol has led to increasing research of the catalytic conversion of glycerol. The selective hydrogenolysis of glycerol is an economical and sustainable way to produce 1,3-propanediol, which experiences a global growing demand, and valorize glycerol. However, the secondary hydroxy group of glycerol is sterically hindered by two primary hydroxy groups. As a result, 1,2-propanediol is the preferential product rather than 1,3-propanediol during conventional hydrogenolysis of glycerol. Currently, tungsten-containing bifunctional catalysts with metal and Brønsted acid sites are considered as a highly effective and atom-economical catalytic system for the selective hydrogenolysis of glycerol to 1,3-propanediol. Therefore, this Minireview summarized various tungsten-containing bifunctional catalysts for the hydrogenolysis of glycerol in detail and deeply discussed the relationship between tungsten species, metal active sites, and glycerol for selectively producing 1,3-propanediol.

Sagittal en bloc resection of primary tumors in the thoracic and lumbar spine: feasibility, safety and outcome.

This study is to test feasibility, safety and the outcome of sagittal en bloc resection of paravertebral primary tumors in the thoracic and the lumbar spine. Sagittal en bloc resection was planned based on WBB classification and performed via combined anterior-posterior or anterior-posterior-lateral approach in 9 consecutive patients with aggressive benign or malignant paravertebral primary tumors in the thoracic and lumbar spine. Surgical margins were evaluated both radiologically and histopathologically. Follow-up data regarding survival rate, local control, morbidity, hardware failure and postoperative function were collected at around 2 years after surgery. En bloc resection was achieved in all patient with wide margin in 7/9 patients, marginal and intralesional margin in 2/9 patients. Survival rate and local control rate were 100%. There were 4/9 cases of major complications and 2/9 cases of minor complications with an overall morbidity rate of 67% (6/9). All but one patient with intraoperative spinal cord injury were free of neurological deficits and fully mobile in absence of any indication of hardware failure. With a careful choice of surgical procedure, sagittal en bloc resection of paravertebral primary tumor in the thoracic and lumbar spine is feasible, safe and effective.

A prospective randomized cohort study on 3D-printed artificial vertebral body in single-level anterior cervical corpectomy for cervical spondylotic myelopathy.

BACKGROUND: This was a prospective randomized cohort study aiming at examining the safety and efficacy of artificial vertebral body (AVB) fabricated by electron beam melting (EBM) in comparison to conventional titanium mesh cage (TMC) used in single-level anterior cervical corpectomy and fusion (SL-ACCF). METHODS: Forty patients with cervical spondylotic myelopathy (CSM) underwent SL-ACCF using either the EBM-AVB or the TMC. Patients were evaluated for their demographics, radiological characteristics, neurologic function [using the Japanese Orthopaedic Association (JOA) scale], and health-related quality-of-life (HRQoL) aspects [using the Short Form 36 (SF-36)] before and after the surgery and comparison was made between the two groups both at baseline and the last follow-up. The Student t-text, paired-sample t-text, and Fisher's exact test were used when appropriate to detect any statistical significance at the level of α=0.05. RESULTS: Post-operative recovery was uneventful for all patients and no revision surgery was required. There were no significant differences between the EBM-AVB group and the TMC group at baseline. Patients in both groups demonstrated significant improvement in cervical alignment, JOA score, and SF-36 score after the surgery. Six months post-operatively, patients in the EBM-AVB group were found to have significantly less loss of fusion height and lower incidence for severe implant subsidence compared with the TMC group. Patients in the two groups were comparable at the last follow-up regarding their rate of fusion, cervical alignment, JOA recovery rate, SF-36 score, and by Odom's criteria. CONCLUSIONS: For CSM patients undergoing SL-ACCF, the EBM-AVB group demonstrated comparable outcomes regarding patient cervical alignment, neurologic function, and HRQoL in comparison with the TMC group. Furthermore, the use of EBM-AVB was associated with decreased loss of the height of the fusion mass and a lower rate for severe implant subsidence.

Upper cervical spine reconstruction using customized 3D-printed vertebral body in 9 patients with primary tumors involving C2.

BACKGROUND: Reconstruction following resection of the primary tumors of the upper cervical spine is challenging, and conventional internal implants develop complications in this region. 3D printing, also known as additive manufacturing, can produce patient-specific porous implants in a particular shape for bone defect reconstruction. This study aimed to describe the clinical outcomes of upper cervical spine reconstruction using customized 3D-printed vertebral body in 9 patients with primary tumors involving C2. METHODS: Patients with primary tumors involving C2 who were treated in our institution between July 2014 and November 2018 were enrolled. A two-stage intralesional spondylectomy was performed using the posterior-anterior approach. Anterior reconstruction was accomplished using a customized 3D-printed vertebral body, which was fabricated by successive layering of melted titanium alloy powder using electron beam melting. No bone graft was used. RESULTS: Nine patients (2 males and 7 females) were included in the study with a mean age of 31.4 years (12 to 59 years). Seven patients demonstrated tumors located in C2 and 2 showed involvement of C2 and C3. During a mean follow-up of 28.6 months (range, 12-42 months), 1 patient died of systemic metastasis and 1 had local tumor recurrence, the other 7 patients were alive and functional in their daily living until the last follow-up without evidence of disease. The 3D-printed vertebral bodies were all stable with no sign of displacement or subsidence, evidence of implant osseointegration was observed on the imaging studies. For the posterior instrumentation systems, no screw loosening or rod breakage was found. CONCLUSIONS: Spinal reconstruction in the upper cervical region using customized 3D-printed vertebral body is reliable. The tailored shape matching with the contact surfaces and the porous structure conductive to osseointegration provide both short- and long-term stability to the implant.