Engineering a triple-functional magnetic gel driving mutually-synergistic mild hyperthermia-starvation therapy for osteosarcoma treatment and augmented bone regeneration.

Malignant bone tumors result in high rates of disability and death and are difficult to treat in terms of killing tumors and repairing bone defects. Compared with other hyperthermia strategies, magnetic hyperthermia has become an effective therapy for treating malignant bone tumors due to its lack of depth limitations. However, tumor cells express heat shock protein (HSP) to resist hyperthermia, which reduces its curative effect. Competitive ATP consumption can reduce HSP production; fortunately, the basic principle of starvation therapy by glucose oxidase (GOx) is consuming glucose to control ATP production, thereby restricting HSP generation. We developed a triple-functional magnetic gel (Fe3O4/GOx/MgCO3@PLGA) as a magnetic bone repair hydrogels (MBRs) with liquid‒solid phase transition capability to drive magneto-thermal effects to simultaneously trigger GOx release and inhibit ATP production, reducing HSP expression and thereby achieving synergistic therapy for osteosarcoma treatment. Moreover, magnetic hyperthermia improves the effect of starvation therapy on the hypoxic microenvironment and achieves a reciprocal strengthening therapeutic effect. We further demonstrated that in situ MBRs injection effectively suppressed tumor growth in 143B osteosarcoma tumor-bearing mice and an in-situ bone tumor model in the rabbit tibial plateau. More importantly, our study also showed that liquid MBRs could effectively match bone defects and accelerate their reconstruction via magnesium ion release and enhanced osteogenic differentiation to augment the regeneration of bone defects caused by bone tumors, which generates fresh insight into malignant bone tumor treatment and the acceleration of bone defect repair.

Advanced polymer hydrogels that promote diabetic ulcer healing: mechanisms, classifications, and medical applications.

Diabetic ulcers (DUs) are one of the most serious complications of diabetes mellitus. The application of a functional dressing is a crucial step in DU treatment and is associated with the patient's recovery and prognosis. However, traditional dressings with a simple structure and a single function cannot meet clinical requirements. Therefore, researchers have turned their attention to advanced polymer dressings and hydrogels to solve the therapeutic bottleneck of DU treatment. Hydrogels are a class of gels with a three-dimensional network structure that have good moisturizing properties and permeability and promote autolytic debridement and material exchange. Moreover, hydrogels mimic the natural environment of the extracellular matrix, providing suitable surroundings for cell proliferation. Thus, hydrogels with different mechanical strengths and biological properties have been extensively explored as DU dressing platforms. In this review, we define different types of hydrogels and elaborate the mechanisms by which they repair DUs. Moreover, we summarize the pathological process of DUs and review various additives used for their treatment. Finally, we examine the limitations and obstacles that exist in the development of the clinically relevant applications of these appealing technologies. This review defines different types of hydrogels and carefully elaborate the mechanisms by which they repair diabetic ulcers (DUs), summarizes the pathological process of DUs, and reviews various bioactivators used for their treatment.

Application of the cortical bone trajectory technique in posterior lumbar fixation.

The cortical bone trajectory (CBT) is a novel technique in lumbar fixation and fusion. The unique caudocephalad and medial-lateral screw trajectories endow it with excellent screw purchase for vertebral fixation via a minimally invasive method. The combined use of CBT screws with transforaminal or posterior lumbar interbody fusion can treat a variety of lumbar diseases, including spondylolisthesis or stenosis, and can also be used as a remedy for revision surgery when the pedicle screw fails. CBT has obvious advantages in terms of surgical trauma, postoperative recovery, prevention and treatment of adjacent vertebral disease, and the surgical treatment of obese and osteoporosis patients. However, the concept of CBT internal fixation technology appeared relatively recently; consequently, there are few relevant clinical studies, and the long-term clinical efficacy and related complications have not been reported. Therefore, large sample and prospective studies are needed to further reveal the long-term complications and fusion rate. As a supplement to the traditional pedicle trajectory fixation technique, the CBT technique is a good choice for the treatment of lumbar diseases with accurate screw placement and strict indications and is thus deserving of clinical recommendation.

Injectable versatile liquid-solid transformation implants alliance checkpoint blockade for magnetothermal dynamic-immunotherapy.

The ongoing circulating energy loss, low reactive oxygen species (ROS) accumulation and poor immunogenicity of tumors make it difficult to induce sufficient immunogenic cell death (ICD) in the tumor immunosuppressive microenvironment (TIME), resulting in unsatisfactory immunotherapy efficacy. Furthermore, for highly malignant tumors, simply enhancing ICD is insufficient for exhaustively eliminating the tumor and inhibiting metastasis. Herein, we propose a unique magnetothermal-dynamic immunotherapy strategy based on liquid-solid transformation porous versatile implants (Fe3O4/AIPH@PLGA) that takes advantage of less energy loss and avoids ongoing circulating losses by minimally invasive injection into tumors. In addition, the magnetothermal effect regresses and eliminates tumors that are not limited by penetration to simultaneously trigger 2,2'-azobis[2-(2-imidazolin-2-yl) propane] dihydrochloride (AIPH) decomposition and generate a large amount of oxygen-irrelevant free radicals and heat shock protein (HSP) accumulation by heating, evoking both intracellular oxidative stress and endoplasmic reticulum (ER) stress to induce large-scale ICD and enhance tumor immunogenicity. More importantly, in orthotopic bilateral breast tumor models, a significant therapeutic effect was obtained after combining amplified ICD with CTLA4 checkpoint blockade. The 21-day primary and distant tumor inhibition rates reached 90%, and the underlying mechanism of the effective synergetic strategy of inducing the T-cell-related response, the immune memory effect and TIME reprogramming in vivo was verified by immune cell analyses. This remarkable therapeutic effect provides a new direction for antitumor immunotherapy based on magnetothermally controlled oxygen-independent free radical release.

Overexpression of TP53INP2 Promotes Apoptosis in Clear Cell Renal Cell Cancer via Caspase-8/TRAF6 Signaling Pathway.

Clear cell renal cell cancer (ccRCC) is a tumor of high malignancy, which can escape apoptosis. The tumor protein p53-inducible nuclear protein 2 (TP53INP2), known as an autophagy protein, is the essential part for autophagosome formation and sensitizes cells to apoptosis. Our study is aimed at exploring the role of TP53INP2 in ccRCC. We have identified the autophagy-related genes (ARGs) of differential expression in ccRCC patients with the help of the TCGA database by bioinformatics analysis. Our assays of quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were for the determination on the both levels of mRNA and protein. Overexpression of TP53INP2 on cellular proliferation, migration, and apoptosis of ccRCC was verified in the ways of performing CCK-8, wound scrape, transwell and flow cytometry assays in vitro, and a mice tumor model in vivo. Transmission electron microscopy was used to measure autophagy formation. The underlying mechanisms of TP53INP2 on ccRCC were determined via coimmunoprecipitation. TP53INP2 was found highly associated with an outcome of worse overall survival (OS) in Kaplan-Meier curves, and this parameter in ccRCC tissues was also lower than the normal tissues. Overexpression of TP53INP2 inhibited ccRCC cellular proliferation, migration, and invasion, as well as the tumor growth of mice. Those cells treated with autophagy inhibitor chloroquine (CQ) or TP53INP2 increased the apoptosis rate. TP53INP2 promoted autophagy formation and elevated the ratio of LC3 II/LC3 I. However, TP53INP2 did not significantly decrease the p-mTOR level. In addition, TP53INP2 activates the expressions of caspase-3, caspase-8, and PARP. Caspase-8 and TNF receptor associated factor 6 (TRAF6) were found to bind to each other in the presence of TP53INP2. TP53INP2 induces apoptosis in ccRCC cells through caspase-8/TRAF6 pathway, rather than the autophagy-dependent pathway.

Mitochondrial Glutathione Depletion Nanoshuttles for Oxygen-Irrelevant Free Radicals Generation: A Cascaded Hierarchical Targeting and Theranostic Strategy Against Hypoxic Tumor.

An oxygen-irrelevant free radicals generation strategy has shown great potential in hypoxic tumor therapy. However, insufficient tumor accumulation, nonspecific intracellular localization, and the presence of highly reductive mitochondrial glutathione (GSH) dramatically hamper the free radicals therapeutic efficacy. Herein, a hierarchical targeting system was constructed by Fe-doped polydiaminopyridine nanoshuttles, indocyanine green (ICG), and an oxygen-irrelevant radicals generator (AIPH) to possess a negative charge. An acid-specific charge-reverse capability of the shuttles was achieved to enhance cell uptake in the tumor microenvironment (TME). In addition, the iron release occurs only in the acidic TME, which can be used as acidity enhancers to strengthen the charge-reverse process, thereby leading to more efficient tumor internalization and deep penetration. Moreover, such a nanosystem has significantly improved the delivery efficiency of nanoshuttles (16.06%) in the tumor tissues at 24 h postinjection, much higher than that of naked Fe-doped polydiaminopyridine (6.59%). More importantly, the nanoshuttles enable simultaneously mitochondria targeting and corresponding GSH depleting capability to show advantages in free radicals-based therapy after charge reversion, leading to a powerful tumor inhibition rate (>95%). The prescence of iron could allow for magnetic resonance imaging, while ICG allowed for photoacoustic imaging and fluorescence imaging to guide the therapeutic process. The remarkable features of the nanoshuttles may open a new avenue to explore an oxygen-irrelevant free radicals generating system for accurate cancer theranostics.

Epidural gas-containing pseudocyst leading to lumbar radiculopathy: A case report.

BACKGROUND: Lumbar radiculopathy is a common symptom in the clinic and is often caused by lumbar disc herniation or osteophytes compressing the nerve root; however, it is rare for nerve roots to be compressed by epidural gas. Few symptomatic epidural gas-containing pseudocyst cases have been reported. Furthermore, the reported cases were due to a mix of gas and obvious osteophytes; therefore, it was hard to rigorously conclude that gas was the factor responsible for radiculopathy. We provide evidence that because no epidural gas accumulated before radiculopathy occurred and the symptoms were relieved after removal of the gas, the epidural gas-containing pseudocyst was the root cause of radiculopathy in this case. CASE SUMMARY: An 87-year-old man with a 3-wk history of right radiating pain was admitted to our hospital. Computed tomography (CT) and magnetic resonance imaging (MRI) examinations showed a vacuum phenomenon and huge lesions with low signal intensity located in the same area where the pain occurred. After carefully checking the images acquired in the last 3 mo, we found an abdominal CT examination performed 40 d prior because of abdominal pain. The CT images showed no gas-containing pseudocyst in the epidural space and notably, he had no leg pain at the time. To ensure a low-intensity intervention and complete decompression of the nerve, percutaneous endoscopic lumbar nerve decompression surgery was advised. A gas-containing pseudocyst was identified under endoscopy. The symptoms were relieved after surgery, and the postoperative images showed total disappearance of the vacuum phenomenon and lesions with low signal intensity on CT and MRI. Histological examination showed that the sampled gas-containing pseudocyst tissue was fibrous connective tissue. CONCLUSION: This case thoroughly illustrates that an epidural gas-containing pseudocyst can result in radiculopathic pain through a comprehensive evidence chain. Percutaneous endoscopic decompression is a minimally invasive and effective treatment method.

A Three-in-One Strategy: Injectable Biomimetic Porous Hydrogels for Accelerating Bone Regeneration via Shape-Adaptable Scaffolds, Controllable Magnesium Ion Release, and Enhanced Osteogenic Differentiation.

The repair of bone defects with irregular shapes, particularly in a minimally invasive manner, remains a major challenge. For synthetic bone grafts, injectable hydrogels are superior to conventional scaffolds because they can adapt satisfactorily to the defect margins and can be injected into deeper areas of injury via a minimally invasive procedure. Based on the poly(lactide-co-glycolide)(PLGA)/1-methyl-2-pyrrolidinone solution reported in our previous study, we successfully synthesized injectable MgO/MgCO3@PLGA (PMM) hydrogels, namely, injectable biomimetic porous hydrogels (IBPHs), to accelerate bone regeneration. In addition to exhibiting excellent injectability, PMM hydrogels could transform into porous scaffolds in situ through a liquid-to-solid phase transition and completely fill irregular bone defects via their superb shape adaptability. Moreover, sustainable and steady release of Mg2+ was achieved by regulating the weight ratio of the incorporated MgO and MgCO3 particles. Via controlled release of Mg2+, PMM hydrogels significantly promoted proliferation, osteogenic differentiation, migration, and biomineral deposition of immortalized mouse embryonic fibroblasts. More importantly, micro-CT imaging and histological analysis indicated that concomitant with their gradual degradation, PMM hydrogels effectively stimulated in situ bone regeneration in rat calvarial defects with an increase in the bone volume fraction of almost 2-fold compared with that in the control group. These findings suggest that injectable PMM hydrogels can satisfactorily match bone defects and form porous scaffolds in situ and can significantly promote bone regeneration via controllable Mg2+ release. The remarkable features of IPBHs may open a new avenue for the exploration of in situ repair systems for irregular bone defects to accelerate bone regeneration and have great potential for clinical translation.

Posterior Percutaneous Transpedicular Endoscopic Approach for Treating Single-Segment Cervical Myelopathy.

BACKGROUND: Standard posterior percutaneous endoscopic cervical discectomy (PECD) is considered an effective minimally invasive surgery. Although standard PECD can be used to treat radiculopathy with relatively minimal trauma, it is still a challenge to use this approach for treating myelopathy. OBJECTIVE: This report is aimed at first describing a posterior transpedicular approach under endoscopy for myelopathy and evaluating the feasibility and short-term clinical effects of this approach. METHODS: In our retrospective analysis between Feb. 2016 to Mar. 2017, 16 patients managed with PECD using the posterior transpedicular approach for symptomatic single-segment myelopathy. Surgery involved drilling 1/2 to 2/3 of the medial portion of the pedicle under endoscopy to provide sufficient space and an appropriate angle for inserting the endoscope into the spinal canal, followed by ventral decompression of the spinal cord. Computed tomography and magnetic resonance imaging were used to evaluate pedicle healing and spinal cord decompression. The primary outcomes included a visual analog scale (VAS) scores of axial neck pain and Japanese Orthopaedic Association (JOA) scores of neurological conditions. RESULTS: All patients completed a 1-year follow-up examination. The mean duration of surgery was 95.44 ± 19.44 min (52-130 min). The fluoroscopy duration was 5.88 ± 1.05 (4-7). The VAS scores of axial pain significantly improved from 6.94 ± 0.75 preoperatively to 2.88 ± 1.22 postoperatively (P < 0.05). The mean JOA scores improved from 8.50 ± 1.12 preoperatively to 14.50 ± 1.46 at the final follow-up (P < 0.05). The effects were excellent in 8 cases, good in 6 cases, and fair in 2 cases. After partial pedicle excision, the width of the remaining pedicle was 1.70 ± 0.22 mm postoperatively and significantly recovered to 3.38 ± 0.49 mm at the 1-year follow-up. There were no surgery-related complications, such as dural tearing, spinal cord injury, nerve root injury, pedicle fracture, and cervical hematocele or infection. CONCLUSIONS: The posterior transpedicular approach is an effective method for the treatment of myelopathy in select patients and is a supplement to the described surgical approach for PECD.

Endoscopically-Assisted Percutaneous Unilateral Atlantoaxial Screw-Rod Nonfusion Fixation Treatment for Type II Odontoid Fractures in Geriatric Patients: Case Series and Technical Note.

BACKGROUND: Considerable controversy exists regarding the optimal treatment for type II odontoid fractures in geriatric patients. Surgical intervention can help patients return to their prior level of function as rapidly as possible while avoiding the morbidity and mortality associated with prolonged and bedbound hospitalization. However, the optimal treatment is still a difficult choice for patients with increased risk from anesthesia. OBJECTIVES: The objective of our study was to describe an innovative method of endoscopically-assisted percutaneous unilateral C1 lateral mass screw and C2 pedicle screw-rod nonfusion fixation for type II odontoid fractures in geriatric patients. STUDY DESIGN: A case series design and technical notes. SETTING: This study took place at Second Affiliated Hospital of Chongqing Medical University. METHODS: Seven geriatric patients (> 65 years) with type II odontoid fractures and an American Society of Anesthesiologists (ASA) score of 2 or higher received endoscopically-assisted percutaneous unilateral atlantoaxial screw-rod nonfusion fixation. After surgery, all patients were required to wear a rigid collar full-time for 12 weeks. Intraoperative data, the bone union time, American Spinal Injury Association (ASIA) scale scores, Neck Disability Index (NDI) scores, and postoperative complications were collected for assessment.RESULTS The surgical goal was successfully achieved in all patients, 3 of whom had high ASA scores (>= 3) and underwent surgery under local anesthesia. The operative time ranged from 112 to 169 minutes (mean, 131.1 minutes). No neurovascular complications were observed intraoperatively or postoperatively. All patients rapidly returned to their prior level of function and were followed up for 12 to 24 months (average: 16.9 months). Bone union was achieved in all patients. LIMITATIONS: This study is limited by being a retrospective study. CONCLUSIONS: Endoscopically-assisted percutaneous unilateral atlantoaxial screw-rod nonfusion fixation is a feasible technique for type II odontoid fractures in geriatric patients. This method offers a compromise between non-operative and operative treatment and allows geriatric patients to rapidly return to their prior level of function. KEY WORDS: Endoscopically-assisted surgery; geriatric patient; percutaneous atlantoaxial fixation; type II odontoid fracture; unilateral nonfusion fixation.

Multifunctional bone cement for synergistic magnetic hyperthermia ablation and chemotherapy of osteosarcoma.

Myelosuppression, gastrointestinal toxicity and hypersensitivities always accompany chemotherapy of osteosarcoma (OS). In addition, the intricate karyotype of OS, the lack of targeted antitumor drugs and the bone microenvironment that provides a protective alcove for tumor cells reduce the therapeutic efficacy of chemotherapy. Here, we developed a multifunctional bone cement loaded with Fe3O4 nanoparticles and the antitumor drug doxorubicin (DOX/Fe3O4@PMMA) for synergistic MH ablation and chemotherapy of OS. The localized intratumorally administered DOX/Fe3O4@PMMA can change from liquid into solid at the tumor site via a polyreaction. The designed multifunctional bone cement was constructed with Fe3O4 nanoparticles, PMMA, and an antitumor drug approved by the U.S. Food and Drug administration (FDA). The injectability, magnetic hyperthermia (MH) performance, controlled drug release profile, and synergistic therapeutic effect of DOX/Fe3O4@PMMA in vitro were investigated in detail. Furthermore, the designed DOX/Fe3O4@PMMA controlled the release of DOX, enhanced the apoptosis of OS tissue, and inhibited the proliferation of tumor cells, demonstrating synergistic MH ablation and chemotherapy of OS in vivo. The biosafety of DOX/Fe3O4@PMMA was also evaluated in detail. This strategy significantly reduced surgical time, avoided operative wounds and prevented patient pain, showing a great clinical translational potential for OS treatment.

Modified K-Hole Percutaneous Endoscopic Surgery for Cervical Foraminal Stenosis: Partial Pediculectomy Approach.

BACKGROUND: Percutaneous endoscopic cervical discectomy has evolved as an efficient, minimally invasive spine surgery for radiculopathy caused by soft and/or osseous foraminal stenosis. Although interlaminar access can be used to resect lateral herniated lesions or osteophytes located in the foramina, with limited operative space, nerve retraction may be unavoidable. This procedure may injure the nerve root and cause postoperative arm pain, numbness, and muscle weakness, especially when the herniation is located in the ventral nerve root or when there is a massive osteophyte in the foramina. However, posterior partial cervical pediculectomy under endoscopy provides a new approach to effectively reduce or even avoid nerve retraction and reduce the potential risk of nerve injury. OBJECTIVES: This report presents a partial pediculectomy approach and compares the clinical outcomes of different surgical methods, including posterior percutaneous endoscopic cervical discectomy (P-PECD) and P-PECD combined with partial pediculectomySTUDY DESIGN: This study used a retrospective comparative study design. SETTING: This study took place at the Second Affiliated Hospital of Chongqing Medical University. METHODS: From February 2015 to March 2017, 84 patients with single-level and unilateral soft and/or osseous cervical foraminal stenosis were recruited. Patients were treated with P-PECD (40 patients) and P-PECD combined with partial pediculectomy (44 patients). Postoperative clinical outcomes were assessed using the modified MacNab grading criteria and the Visual Analog Scale (VAS) at different times after surgery. The surgery duration, dosage of postoperative analgesic medication, duration of hospital stay, and postoperative complications were recorded. RESULTS: The mean duration of the conventional P-PECD surgery was 74.48 ± 7.08 minutes, which was significantly longer (P = 0.002) than that observed for the P-PECD with partial pediculectomy (66.00 ± 9.62 minutes). The analgesic dosage in the conventional P-PECD group was significantly higher than that in the partial pediculectomy group (9.14 ± 3.07 units vs. 5.71 ± 3.41 units; P = 0.001). The hospital stay in the conventional P-PECD group was significantly longer than that in the partial pediculectomy group (3.86 ± 0.85 days vs. 3.24 ± 0.83 days; P = 0.022). The VAS scores at 1 day, 3 days, and 7 days after surgery in the conventional P-PECD group were significantly higher than those in the partial pediculectomy group (all P < 0.001). The modified MacNab grading criteria showed no significant difference at each follow-up (P = 1). The incidence of complications in the P-PECD with partial pediculectomy group (2/44, 4.55%) was significantly lower than that in the conventional P-PECD group (4/40, 10.0%), including complications of increased pain, increased numbness, and worsening of muscle weakness. LIMITATIONS: This study is limited by being a retrospective study, and by having a small sample size and a short follow-up period. CONCLUSIONS: As an alternative to the P-PECD surgical technique, P-PECD with partial pediculectomy effectively reduced the postoperative complications and may be preferable when considering the surgery duration, postoperative hospital stay, analgesic dosage, and postoperative VAS score. KEY WORDS: Cervical disc herniation, foraminal stenosis, percutaneous endoscopic cervical discectomy, PECD, P-PECD, partial pediculectomy.

PMMA-Fe3O4 for internal mechanical support and magnetic thermal ablation of bone tumors.

Background: Minimally invasive modalities are of great interest in the field of treating bone tumors. However, providing reliable mechanical support and fast killing of tumor cells to achieve rapid recovery of physical function is still challenging in clinical works. Methods: A material with two functions, mechanical support and magnetic thermal ablation, was developed from Fe3O4 nanoparticles (NPs) distributed in a polymethylmethacrylate (PMMA) bone cement. The mechanical properties and efficiency of magnetic field-induced thermal ablation were systematically and successfully evaluated in vitro and ex vivo. CT images and pathological examination were successfully applied to evaluate therapeutic efficacy with a rabbit bone tumor model. Biosafety evaluation was performed with a rabbit in vivo, and a cytotoxicity test was performed in vitro. Results: An NP content of 6% Fe3O4 (PMMA-6% Fe3O4, mFe: 0.01 g) gave the most suitable performance for in vivo study. At the 56-day follow-up after treatment, bone tumors were ablated without obvious side effects. The pathological examination and new bone formation in CT images clearly illustrate that the bone tumors were completely eliminated. Correspondingly, after treatment, the tendency of bone tumors toward metastasis significantly decreased. Moreover, with well-designed mechanical properties, PMMA-6%Fe3O4 implantation endowed tumor-bearing rabbit legs with excellent bio-mimic bone structure and internal support. Biosafety evaluation did not induce an increase or decrease in the immune response, and major functional parameters were all at normal levels. Conclusion: We have presented a novel, highly efficient and minimally invasive approach for complete bone tumor regression and bone defect repair by magnetic thermal ablation based on PMMA containing Fe3O4 NPs; this approach shows excellent heating ability for rabbit VX2 tibial plateau tumor ablation upon exposure to an alternating magnetic field (AMF) and provides mechanical support for bone repair. The new and powerful dual-function implant is a promising minimally invasive agent for the treatment of bone tumors and has good clinical translation potential.

An artificially engineered "tumor bio-magnet" for collecting blood-circulating nanoparticles and magnetic hyperthermia.

It is a great challenge to directly endow a tumor with specific functions for theranostic treatment. In this study, we report on a novel approach to transform a tumor into a "bio-magnet", to be magnetized on demand, in order to create an intrinsic tumor magnetic field that would collect magnetic nanoparticles (MNPs) circulating in the blood and achieve simultaneous magnetic hyperthermia. This was achieved by the localized intratumoral injection of liquid Nd2Fe14B/Fe3O4-PLGA, followed by solvent exchange that induces a liquid-to-solid transformation. After the magnetism charging process, the solid Nd2Fe14B/Fe3O4-PLGA implant was endowed with permanent magnetic properties and in situ created the magnetic field within the tumor tissue, making the tumor a "bio-magnet". After the creation of the bio-magnet, intravenously injected MNPs accumulated into the tumor tissue due to the tumor magnetic field. Importantly, both the in vitro and ex vivo results demonstrated the high efficiency of the implanted bio-magnet for magnetic hyperthermia. This new approach achieves magnetic targeting by creating a tumor "bio-magnet", which generates a strong magnetic field within the tumor, paving a new way for the development of an efficient targeting strategy for tumor therapy.

Biomechanical Study of Novel Unilateral Fixation Combining Unilateral Pedicle and Contralateral Translaminar Screws in the Subaxial Cervical Spine.

INTRODUCTION: In several situations, the stability of the subaxial cervical spine is damaged and involves the lateral mass of 1 side; in these cases, a pedicle screw (PS) or lateral mass screw (LMS) may not be suitable for placement on the affected side. Therefore, salvage short-segment fixation with satisfactory stability is needed when bilateral fixation is not feasible. METHODS: Seven fresh-frozen human cervical spine specimens were used to test the 3-plane range of motion (ROM) of the C4-C5 segment. Quasistatic 2-Nm flexibility testing was performed in the following sequence: 1) intact; 2) destabilization (using 3-column injury models) treated with bilateral mass screws (BMSs); 3) destabilization treated with a unilateral PS combined with a contralateral translaminar screw (UPS+CTLS); and 4) destabilization treated with bilateral PSs (BPSs). Then, a pullout strength test was performed for the PSs, LMSs, and translaminar screws (TLSs) using 7 isolated C4 and C5 vertebrae. RESULTS: The UPS+CTLS group showed no significant difference from the BMS group in the 3-plane ROM or from the BPS group in the axial rotation or flexion-extension ROM but showed a significantly greater lateral bending ROM than did the BPS group. The pullout strength test showed that both C4 and C5 TLSs had strength similar to that of LMSs but poorer than that of PSs. CONCLUSIONS: Fixation with the hybrid UPS+CTLS construct performed as well as BMS fixation in our biomechanical tests and may play a clinical role when BPS or BMS placement is not feasible for short-segment fixation.

Anterior Transcorporeal Approach to Percutaneous Endoscopic Cervical Diskectomy for Single-Level Cervical Intervertebral Disk Herniation: Case Series with 2-Year Follow-Up.

OBJECTIVE: To examine the effects of anterior transcorporeal percutaneous endoscopic cervical diskectomy (ATPECD) for the treatment of single-level cervical intervertebral disk herniation (CIDH) with a focus on its safety, feasibility, clinical efficacy, and specific possible complications. METHODS: A series of 35 patients with symptomatic single-level CIDH were enrolled to be treated with ATPECD. Neck and arm pain was measured using the visual analog scale. Quality of life was measured using the bodily pain and physical function on the SF-36. The average disk height and vertical vertebral body height were recorded. Bone healing was evaluated on the basis of postoperative computed tomography. RESULTS: Successful removal of the herniated disk was confirmed in all 35 cases. At 2 years, the patients showed a significant treatment effect in the visual analog scale and body pain and physical function portions of the SF-36 (1.14 ± 0.60 vs. 7.62 ± 0.61, 63.92 ± 6.74 vs. 32.55 ± 6.80, and 82.14 ± 6.22 vs. 34.43 ± 4.50, respectively, P < 0.01). Mean preoperative disk height was 6.79 ± 0.37 mm, which decreased to 6.34 ± 0.46 mm 2 years post operation (6.6% decrease). Preoperative surgical vertebral body height also decreased from preoperation (15.79 ± 0.52 mm) to 2 years post operation (15.12 ± 0.38 mm) (4.2% decrease). Three surgery-related complications were observed (8.6%). CONCLUSIONS: Preliminary clinical experience with ATPECD shows that it is safe, effective, feasible, and minimally invasive. Although it has some disadvantages, such as the need for repeated fluoroscopy, some minor complications, and nonsymptomatic disk height decreases, ATPECD can supplement minimally invasive surgeries in selected cases of CIDH.

Treatment of Single-Level Thoracic Tuberculosis by Percutaneous Endoscopic Débridement and Allograft via the Transforaminal Approach Combined with Percutaneous Pedicle Screw Fixation: A Multicenter Study with a Median Follow-Up of 36 Months.

OBJECTIVE: To examine effects of percutaneous endoscopic débridement and allograft via the transforaminal approach combined with percutaneous pedicle screw fixation as treatment for single-level thoracic tuberculosis. METHODS: This multicenter retrospective analysis included 75 patients with single-level thoracic tuberculosis who underwent percutaneous endoscopic débridement and allograft via the transforaminal approach combined with percutaneous pedicle screw fixation and were followed for >36 months between January 2012 and December 2014. RESULTS: Follow-up was 36-48 months (average 41.1 ± 2.2 months). Intraoperative blood loss was low (average 30.5 ± 7.9 mL), and bed rest time was short (average 1.5 ± 0.3 days). No recurrence was observed in all 75 patients. Except for 3 patients, almost all patients (96%) achieved grade I or II fusion in interbody bone grafting. Segmental Cobb angle was 13.5° ± 4.1° before surgery, 10.5° ± 3.7° immediately after surgery, and 11.7° ± 3.9° at 36 months of follow-up. All patients achieved complete recovery of neurologic function (American Spinal Injury Association grade E), including 15 patients with spinal cord injury (American Spinal Injury Association grade D) before surgery. The visual analog scale and 36-Item Short-Form Health Survey scores significantly improved at 1, 3, 12, and 36 months of follow-up. No complications related to internal fixation occurred within the follow-up period; complication rate was 9.0%. CONCLUSIONS: Median follow-up clinical experience with percutaneous endoscopic débridement and allograft via the transforaminal approach combined with percutaneous pedicle screw fixation indicates that the technique is safe, effective, feasible, and minimally invasive.

A Novel Posterior Trench Approach Involving Percutaneous Endoscopic Cervical Discectomy for Central Cervical Intervertebral Disc Herniation.

OBJECTIVE: This report describes a novel posterior trench approach involving percutaneous endoscopic cervical discectomy (PECD) for central cervical intervertebral disc herniation (CIVDH) and an evaluation of the feasibility, safety, and short-term clinical effect of this approach. BACKGROUND CONTEXT: Central CIVDH is considered the contraindication for posterior PECD. MATERIALS AND METHODS: A single-center retrospective observational study was performed with 30 patients managed with posterior PECD using the trench approach for symptomatic single-level central CIVDH. Primary outcomes included the measures of bodily pain and physical function based on the SF-36 and modified MacNab criteria. Radiographical follow-up included the static and dynamic cervical plain radiographs, computed tomographic scans, and magnetic resonance images. RESULTS: A positive clinical response for symptom relief was achieved in all patients. The postoperative MRI showed total removal of the herniated disc. CONCLUSIONS: As a supplement to the described surgical techniques of PECD, this trench approach provides novel access for the treatment of CIVDH, especially for the central type. The advantages of this technique include the provision of access to decompress the ventral region of the thecal sac and the ability to avoid damage to the facet joint. The steep learning curve might be a major disadvantage, and the sample volume is a limitation of the study; the effectiveness and reliability of the trench approach should be further verified in a comparative cohort study with a large volume of patients.

Usage of Bone Wax to Facilitate Percutaneous Endoscopic Cervical Discectomy Via Anterior Transcorporeal Approach for Cervical Intervertebral Disc Herniation.

BACKGROUND: Currently, anterior transdiscal access and posterior interlaminar approach are the main approaches for percutaneous endoscopic cervical discectomy (PECD). To overcome access shortcomings, we previously described a novel anterior endoscopic transcorporeal approach on a migrated cervical disc. We innovatively introduced bone wax into endoscopic surgery to aid hemostasis and facilitate the process of drilling an intracorporeal tunnel. METHODS: Five patients with cervical intervertebral disc herniation (CIDH) were treated by PECD via the anterior transcorporeal approach. During the operation, we marked the punctured tunnel with bone wax containing indigo carmine as a guide and smeared bone wax on the endoscopic burr to aid hemostasis. RESULTS: A satisfactory clinical outcome was observed in all 5 patients postoperatively; pain and neurologic condition were dramatically improved. Surgery-related complications, such as esophageal injury, vascular rupture, hematoma, intervertebral disc infection, or postoperative headache, were not encountered. A computed tomography scan was used to observe the process of bone healing. At 3-month postoperative follow-up, the bone defect within the drilling tunnel had partially shrank and was completely healed at 6 months postoperatively. CONCLUSIONS: The anterior endoscopic transcorporeal approach for PECD is a novel, valuable alternative for the treatment of CIDH. Bone wax could indeed facilitate the operation by guiding the drilling process and instantly controlling the bleeding without obvious interference with bone healing. Long-term follow-up is warranted in further clinical studies.

Percutaneous Endoscopic Retrieval of Intraspinal Cement Leakage: Technical Note.

OBJECTIVE: We sought to preliminarily explore the efficacy and safety of percutaneous endoscopic spinal surgery for epidural cement leakage. We report a case series of patients who underwent percutaneous retrieval of leaked epidural cement and achieved spinal decompression under endoscopy. METHODS: Five patients with neurologic impairment due to epidural cement leakage after percutaneous vertebroplasty were treated with percutaneous endoscopic spinal decompression. Computed tomography reconstruction and 3-dimensional imaging were used to evaluate the extruded material. During follow-up at 3, 6, and 12 months postoperatively, all patients were advised to undergo plain radiograph and computed tomography examinations. RESULTS: The leaked epidural cement was successfully removed in all patients under percutaneous endoscopy through a unilateral or bilateral approach. At the 12-month follow-up, the visual analog scale score of all patients improved. In addition, the neurologic function of each patient improved to at least 1 grade level, as evaluated using the American Spinal Injury Association. According to the modified MacNab criteria, 2 patients had excellent recovery, whereas the other 3 patients had good recovery. CONCLUSIONS: We described a novel and minimally invasive procedure to ameliorate intractable epidural cement extrusion. As an alternative to conventional laminectomy, percutaneous endoscopic retrieval achieved the targeted decompression without damaging the posterior lamina. Moreover, the whole operation was performed under regional anesthesia accompanied with dexmedetomidine sedation, allowed real-time neural function evaluation, and had lower risks of anesthesia-related complications, compared with general anesthesia.