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Background Radical resection is the first-line option in managing cervical primary chondrosarcoma. Favorable anterior reconstruction is challenging after multilevel total spondylectomy in the cervical spine. Objective To illustrate the application of piezoelectric surgery and three-dimensional (3D) printing techniques in spine surgery. Methods A 27-yr-old patient was referred to our center with complaints of nocturnal neck pain and right upper extremity weakness. A 2-stage radical tumor resection was conducted using piezoelectric surgery with pathologically tumor-free margins. A 3D-printed titanium microporous prosthesis (3D-PTMP) was designed to reconstruct the anterior column of the cervical spine between C1 and T1 for stability. Results The whole intraoperative blood loss was 2300 mL over the 2 procedures. The patient had an uneventful recovery, regaining ambulatory status 3 wk after the 2 operations without ventilator support or other severe complications. By the final 14-mo follow-up, the patient had achieved marked pain relief and favorable neurological improvement; a postoperative computed tomography scan indicated a good position of the 3D-printed construct between the endplates with no sign of tumor recurrence or implant subsidence. Conclusion The applications of piezosurgery in total spondylectomy and in 3D-PTMP in reconstruction can be a favorable alternative for managing multilevel cervical spinal tumors. Further studies are warranted to validate this surgical strategy.

Multi-level reconstruction incorporating the chest wall and ribs is technically demanding after multi-segmental total en bloc spondylectomy (TES) of thoracic spinal tumours. Few surgical techniques are reported for effective reconstruction. A novel and straightforward technical reconstruction through posterior-lateral approach was presented to solve the extensive chest wall defect and prevent occurrences of severe respiratory dysfunctions after performing TES. The preliminary outcomes of surgery were reviewed. Multi-level TES was performed for five patients with primary or recurrent thoracic spinal malignancies through posterior-lateral approach. The involved ribs and chest wall were removed to achieve tumour-free margin. Then titanium mesh with allograft bone and pedicle screw-rod system were adopted for the circumferential spinal reconstruction routinely. Titanium rods were modified accordingly to attach to the screw-rod system proximally, and the distal end of rods was dynamically inserted into the ribs. The mean surgery time was 6.7 hours (range 5–8), with the average blood loss of 3260 ml (range 2300–4500). No severe neurological complications were reported while three patients had complaints of slight numbness of chest skin (no. 1, 3, and 5). No severe respiratory complications occurred during peri-operative period. No implant failure and no local recurrence or distant metastases were observed with an average follow-up of 12.5 months. The single-stage reconstructions incorporating spine and chest wall are straightforward and easy to perform. The preliminary outcomes of co-reconstructions are promising and favourable. More studies and longer follow-up are required to validate this technique.

Giant cell tumor of the bone (GCTB) is a locally aggressive tumor with a certain distant metastatic rate. For sacral GCT (SGCT) and pelvic GCT (PGCT), surgery has its limitations, especially for unresectable or recurrent tumors. Selective arterial embolization (SAE) is reported to be an option for treatment in several cases, but there are few systematic reviews on the effects of SAE on SGCT and/or PGCT. Medline and Embase databases were searched for eligible English articles. Inclusion and exclusion criteria were conducted before searching. All the clinical factors were measured by SPSS software, with P‐values ≤0.05 considered statistically significant. A total of 9 articles were retrieved, including 44 patients receiving SAE ranging from 1 to 10 times. During the mean follow‐up period of 85.8 months, the radiographic response rate was 81.8%, with a local control and overall survival rate of 75% and 81.8%, respectively. No bowel, bladder, or sexual dysfunction was observed. Three patients developed distant metastases and finally died. Patients with primary tumors tended to have better prognosis than those with recurrence (P = 0.039). The favorable outcomes of SAE suggest that it may be an alternative treatment for SGCT and PGCT patients for whom surgery is not appropriate.

Purpose Clear cell sarcoma (CCS) is a rare high-grade malignant tumor accounting for less than 1% of all soft tissue sarcomas. CCS in the spine is much rarer and poorly understood. The objective of our study is to discuss clinical characteristics, surgical management and outcomes of spinal CCS. Methods Between October 2011 and December 2014, five patients with spinal CCS underwent surgical treatment in our center. Five cases from literature focusing on the spinal CCS were also reviewed. We retrospectively analyzed clinical data and outcome of all ten patients to present our understanding of spinal CCS. Results Three en bloc and two piecemeal resections were performed successfully. The syndromes of all the patients were obviously relieved after operation. The mean follow-up period was 24.4 months (range 10–41 months). Two patients died of lung metastasis 10 and 26 months after operation respectively. One patient was alive with tumor recurrence. Other two patients were alive with no evidence of disease at last follow-up. Conclusions Prognosis of spinal CCS tend to be worse than CCS in common sites. En bloc resection could be regarded as the first treatment option. Tumor size, tumor location, preoperative neurological status and resection mode might be the potential prognostic factors of spinal CCS.

OBJECTIVEThe objective of this study was to investigate the effect of long-term bisphosphonate treatment on reducing local recurrence of sacral giant cell tumors (GCTs) after nerve-sparing surgery.METHODSThirty-five consecutive patients with sacral GCTs who received treatment in Shanghai Changzheng Hospital between January 2000 and December 2010 were included in this study. Between January 2007 and December 2010, 19 patients received bisphosphonates following nerve-sparing surgery. Before January 2007, 16 patients received nerve-sparing surgery alone, and these cases were included as the control group. The difference in clinical data between the groups was compared by Student's t-test and 2-tailed chi-square or Fisher's exact test. The postoperative recurrence-free survival (RFS) and overall survival (OS) rates were estimated by the Kaplan-Meier method and compared between the groups by log-rank test. A p value < 0.05 was considered statistically significant.RESULTSAll of the patients had relatively good nerve function. The clinical data were homogeneous between the groups. The local recurrence rate was 10.53% (2 of 19) in the bisphosphonate treatment group and 43.75% (7 of 16) in the control group. The log-rank test showed that the 3-year RFS and 3-year OS in the bisphosphonate treatment group were significantly higher than those in the control group (RFS 89.5% vs 56.3%, p = 0.04; OS 100% vs 81.3%, p = 0.05).CONCLUSIONSThe long-term use of bisphosphonates after nerve-sparing surgery is a viable option for the treatment of sacral GCTs. This approach could reduce local recurrences while preserving nerve function.

A retrospective study.To describe a new surgical technique for total en bloc spondylectomy (TES) of the fifth lumbar (L5) tumor and evaluate the efficacy and safety of this new technique.TES has been considered an optimal treatment for tumor, including certain spinal tumors, but it requires a combined posterior-anterior approach, which is often complicated by a long operation time, considerable blood loss and severe trauma.Seven patients with primary or solitary metastatic tumors of L5 were treated with this new technique in our center between March 2014 and November 2017. The critical points were fabrication of the iliac graft, dissection, resection, and reconstruction. Other parameters including surgical time, blood loss, complications, pre- and postoperative neurological function, tumor control, and overall survival (OS) were presented and analyzed.All the included patients received one stage TES. The mean surgical time was 365.7 minutes with an average blood loss of 2514.3 mL. No serious perioperative complication was observed or reported during the mean follow-up period of 27.4 months. Wound disruption occurred in one patient and numbness of the left lower limb in another, but both recovered rapidly after appropriate management. Adventitial avulsion of the abdominal aorta occurred during dissection in one patient. Two patients died during the follow-up period due to advanced malignancy. One patient was alive but developed a newly diagnosed thoracolumbar tumor in 40 months. The other four patients recovered well without evidence of disease. All patients were able to walk independently 3 to 4 weeks after operation, with satisfied fusion of the iliac grafts in a mean period of 6.7 months after operation. No evidence of internal fixation failure occurred.This new technique offers satisfactory surgical exposure, total en bloc spondylectomy, reliable reconstruction, and good tumor control for certain L5 tumors through the posterior-only approach.4.

Background Reconstruction of thoracolumbar structural stability is a formidable challenge for spine surgeons after vertebral body tumor resection. Various disadvantages of the currently used expandable or nonexpandable cages have limited their clinical applications. We sought to develop a novel prosthesis for clinical use and assess its preliminary clinical outcome in reconstruction of thoracolumbar structural stability after spinal tumor resection. Methods Using data obtained from a retrospective analysis of the morphological characteristics of the thoracolumbar vertebrae and endplates in previously reported studies, we modified the nano-hydroxyapatite/polyamide-66 (n-HA/PA66) strut into a novel height-adjustable vertebral body. A retrospective study was performed of 7 patients who had undergone reconstruction of thoracolumbar structural stability with this novel prosthesis from August 2016 to January 2017. Results A novel height-adjustable vertebral body (AHVB) composed of n-HA/PA66 with 2 separate components with a 163° contact surface at each end was manufactured. The height-adjustable range was 28–37 mm. No significant implant-related complications were observed in the process of operation. All patients experienced a significant reduction in pain, with the visual analog scale score decreasing from 7.9 to 4.0. Neurological improvement was assessed using the Frankel grading system after surgery. Postoperative radiographic and computed tomography/magnetic resonance imaging findings indicated that the operated segment was stable, the outcome of kyphosis correction was good, and no prosthesis subsidence or dislocation was observed. Conclusion This novel prosthesis has many advantages in the reconstruction of height, lordosis, and alignment after thoracolumbar spinal tumor resection and has a favorable prospect for clinical application.

Hydraulic Engine Mounts (HEM) are important vibration isolation components with compound structure in the vehicle powertrain mounting system. They have the characteristic that large damping and high dynamic stiffness in the high frequency region, and small damping and low dynamic stiffness in the low frequency region, which can meet the requirements of the vehicle powertrain mounting system better. The method to identify the lumped parameters of the HEM is not only the necessary work for the analysis and calculation in dynamic performance and can also provide the theory for the performance optimization and structure optimization of product in the future. The parameter identification method based on coupled fluid-structure interaction (FSI) and finite element analysis (FEA) was established in this study to identify the equivalent piston area of the rubber spring, the volume stiffness of the upper chamber, as well as the inertia coefficient and damping coefficient of the liquid through the inertia track. The simulated dynamic characteristic curves of the HEM with the parameters identified are in accordance with the measured dynamic characteristic curves well.

On basis of IGBT control technology, a novel neutral grounding impedance optimal control system is proposed in this paper. The method is implemented by passive IGBT circuit to compensate the capacitive current in distribution network. When the operation of distribution network is normal, the IGBT circuit is off, the power frequency overvoltage will not be produced; when the single-phase grounding fault occurs, the IGBT circuit is on, the arc-suppression coil is put into operation, then through the corresponding control strategy of the IGBT on-off control, the grounding fault current can be fully compensated, fault arc can be extinguished instantaneously. The theory analysis and the MATLAB simulation results show that the proposed method has quick speed, wide adjustment range and low cost, the inductor-current can be adjusted continuously, the grounding fault current can be compensated effectively.

Electronic Current Transformer (ECT) is an important equipment when constructing a major digital substation. The power supply of the ECT is intended solely for providing the DC power supply that could ensure the data collecting system's normal working. And which is the key way to ensure the reliability and accuracy of ECT. A new model of the power supply based on the characteristics of ECT is proposed: the UPS system, which utilizes a special current transformer and optical power supply as an overall. In order to fit for the urgent requirement of the digital substation, a hardware circuits is designed to realize the proposal. the research of electronic current transformer ECT attracts more and more attention.