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Fibrin plays a crucial role in peripheral nerve regeneration, which could occur spontaneously in the format of longitudinally oriented fibrin cables during the initial stage of nerve ...regeneration. This fibrin cable can direct migration and proliferation of Schwann cells and axonal regrowth, which is very important to nerve regeneration. In the present study, we prepared a three-dimensional hierarchically aligned fibrin nanofiber hydrogel (AFG) through electrospinning and molecular self-assembly to resemble the architecture and biological function of the native fibrin cable. The AFG displayed a hierarchically aligned topography as well as low elasticity (∼1.5kPa) that were similar to nerve extracellular matrix (ECM) and the native fibrin cable. Rapid, directional cell adhesion and migration of Schwann cells (SCs) and dorsal root ganglions were observed in vitro. The AFG was then used as a potential intraluminal substrate in a bioengineered chitosan tube to bridge a 10-mm-long sciatic nerve gap in rats. We found that the AFG served as a beneficial microenvironment to support SCs cable formation and axonal regrowth within 2weeks. Further histological and morphological analyses as well as electrophysiological and functional examinations were performed after AFG implantation for up to 12weeks. The results from morphological analysis and electrophysiological examination indicated that regenerative outcomes achieved by our developed graft were close to those by an autologous nerve graft, but superior to those by hollow chitosan tubes (hCST) and random fibrin nanofiber hydrogel (RFG). Our results demonstrate that the AFG creates an instructive microenvironment by mimicking the native fibrin cable as well as the oriented and soft features of nerve ECM to accelerate axonal regrowth, thus showing great promising potential for applications in neural regeneration.
In peripheral nervous system defect repair, a wide variety of strategies have been proposed for preparing functionalized nerve guidance conduits (NGC) with more complex configurations to obtain optimal repair effects. Longitudinally oriented fibrin cables were reported to form spontaneously during the initial stages of peripheral nerve regeneration in an empty NGC, which can direct the migration and proliferation of Schwann cells and promote axonal regrowth. Therefore, based on the biomimetic idea, we prepared a three-dimensional hierarchically aligned fibrin nanofiber hydrogel (AFG) through electrospinning and molecular self-assembly, resembling the architecture and biological function of the native fibrin cable and serving as an intraluminal filling to accelerate axon regeneration. We found that the AFG was a beneficial microenvironment to support SCs cable formation and accelerate axonal regrowth with improved motor functional recovery.
MINI: A 3D printing technology is proposed for reconstructing multilevel cervical spine (C2-C4) after resection of metastatic papillary thyroid carcinoma. The personalized porous implant printed in ...Ti6AL4V provided excellent physicochemical properties and biological performance, including biocompatibility, osteogenic activity, and bone ingrowth effect.
A unique case report.
A three-dimensional (3D) printing technology is proposed for reconstructing multilevel cervical spine (C2-C4) after resection of metastatic papillary thyroid carcinoma in a middle-age female patient.
Papillary thyroid carcinoma is a malignant neoplasm with a relatively favorable prognosis. A metastatic lesion in multilevel cervical spine (C2-C4) destroys neurological functions and causes local instability. Radical excision of the metastasis and reconstruction of the cervical vertebrae sequence conforms with therapeutic principles, whereas the special-shaped multilevel upper-cervical spine requires personalized implants. 3D printing is an additive manufacturing technology that produces personalized products by accurately layering material under digital model control via a computer. Reporting of this recent technology for reconstructing multilevel cervical spine (C2-C4) is rare in the literature.
Anterior-posterior surgery was performed in one stage. Radical resection of the metastatic lesion (C2-C4) and thyroid gland, along with insertion of a personalized implant manufactured by 3D printing technology, were performed to rebuild the cervical spine sequences. The porous implant was printed in Ti6AL4V with perfect physicochemical properties and biological performance, such as biocompatibility and osteogenic activity. Finally, lateral mass screw fixation was performed via a posterior approach.
Patient neurological function gradually improved after the surgery. The patient received 11/17 on the Japanese Orthopedic Association scale and ambulated with a personalized skull-neck-thorax orthosis on postoperative day 11. She received radioiodine I therapy. The plane x-rays and computed tomography revealed no implant displacement or subsidence at the 12-month follow-up mark.
The presented case substantiates the use of 3D printing technology, which enables the personalization of products to solve unconventional problems in spinal surgery.
5.
Death happening due to massive hemorrhage has been involved in military conflicts, traffic accidents, and surgical injuries of various human disasters. Achieving rapid and effective hemostasis to ...save lives is crucial in urgent massive bleeding situations. Herein, a covalent cross‐linked AG‐PEG glue based on extracellular matrix‐like amino‐gelatin (AG) and PEG derivatives is developed. The AG‐PEG glue gelatinizes fast and exhibits firm and indiscriminate close adhesion with various moist tissues upon being dosed. The formed glue establishes an adhesive and robust barrier to seal the arterial, hepatic, and cardiac hemorrhagic wounds, enabling it to withstand up to 380 mmHg blood pressure in comparison with normal systolic blood pressure of 60–180 mmHg. Remarkably, massive bleeding from a pig cardiac penetrating hole with 6 mm diameter is effectively stopped using the glue within 60 s. Postoperative indexes of the treated pig gradually recover and the cardiac wounds regrow significantly at 14 days. Possessing on‐demand solubility, self‐gelling, and rapid degradability, the AG‐PEG glue may provide a fascinating stop‐bleeding approach for clinical hemostasis and emergency rescue.
A new bioglue is composed of amidated‐gelatin and Tetra‐PEG‐SS for rapid hemostasis in massive hemorrhage. The amino terminals in gelatin quickly react with active ester moieties in the PEG‐SS, endowing the amino‐gelatin‐PEG glue firm and indiscriminate adhesion with various moist tissues (e.g., adhesively sealing cardiac hemorrhagic wounds). The bioglue provides a fascinating hemostatic approach for clinical hemostasis and emergency rescue.
Current simultaneous localization and mapping (SLAM) algorithms perform well in static environments but easily fail in dynamic environments. Recent works introduce deep learning-based semantic ...information to SLAM systems to reduce the influence of dynamic objects. However, it is still challenging to apply a robust localization in dynamic environments for resource-restricted robots. This paper proposes a real-time RGB-D inertial odometry system for resource-restricted robots in dynamic environments named Dynamic-VINS. Three main threads run in parallel: object detection, feature tracking, and state optimization. The proposed Dynamic-VINS combines object detection and depth information for dynamic feature recognition and achieves performance comparable to semantic segmentation. Dynamic-VINS adopts grid-based feature detection and proposes a fast and efficient method to extract high-quality FAST feature points. IMU is applied to predict motion for feature tracking and moving consistency check. The proposed method is evaluated on both public datasets and real-world applications and shows competitive localization accuracy and robustness in dynamic environments. Yet, to the best of our knowledge, it is the best-performance real-time RGB-D inertial odometry for resource-restricted platforms in dynamic environments for now. The proposed system is open source at: https://github.com/HITSZ-NRSL/Dynamic-VINS.git
Transplantation of a biosynthetic nerve conduit carrying neuro-protective cytokines is promising for treating peripheral nerve injury. Here we developed a novel strategy for repairing sciatic nerve ...injury by EPO-loaded Chitosan nerve conduit (EPO/Chi) and sandwiched-in transplantation of mesenchymal stem cells (MSCs). Then, the beneficial effect of EPO/Chi + MSCs on nerve regeneration was also further investigated by in vitro cellular experiments. In vivo experiment showed that combination of EPO-loaded Chitosan nerve conduit with MSCs could significantly accelerate nerve healing and improve morphological repair. Furthermore, the in vitro cellular experiments results demonstrated that the loaded EPO in nerve conduit could significantly reinforce the repair performance of both MSCs and Schwann cells, which may also contribute to the therapeutic outcome of the EPO/Chi + MSCs strategy. Collectively, the EPO-loaded nerve conduit and sandwiched-in transplantation of MSCs we reported in the study may represent a new potential strategy for peripheral nerve reconstruction.
To evaluate the clinical efficacy of the Medial Sustain Nail (MSN) for medial comminuted trochanteric fractures fixation in comparison to Proximal Femoral Nail Antirotation (PFNA) through a clinical ...study.
A non-inferiority randomized controlled trial was conducted at a single centre between July 2019 and July 2020. Fifty patients diagnosed comminuted trochanteric fractures were randomly assigned to either the MSN group (n = 25) or the PFNA group (n = 25). A total of forty-three patients were included in the final study analysis. The primary outcome measure was Short Form 36 health surgery physical component summary (SF-36 PCS) score. Secondary outcomes included the Oxford Hip Scores (OHS), weight bearing, complication relate to implant and so on. This study was not blined to surgeons, but to patients and data analysts.
The MSN demonstrated significantly better functional outcomes as measured by SF-36 PCS and OHS at six months postoperative compared to PFNA (p < 0.05). Union of fractures in the MSN group reached 90.9% at three months after surgery, whereas the PFNA group achieved a union rate of 57.1% (p < 0.05). Furthermore, weight-bearing time of MSN group was earlier than PFNA group (p < 0.05). Additionally, complications related to implant usage were more prevalent in the PFNA group (33.3%) compared to the MSN group (4.5%) (p < 0.05).
MSN exhibited superior quality of life outcomes compared to PFNA at six months postoperative. This indicates that MSN effectively reconstructs medial femoral support in patients with comminuted trochanteric fractures, which facilitates early weight-bearing and accelerates the recovery process.
Trial registration number: NCT01437176, Date of the trial registration:2011-9-1, Date of commencement of the study:2011-9, Date of enrolment/recruitment of the study subjects:2019-7.
To compare the effectiveness of arthroscopic and conservative treatments in patients with knee osteoarthritis (KOA) with 5 years of follow-up.
Patients diagnosed with Kellgren-Lawrence grade 2 to 4 ...KOA who underwent arthroscopic or conservative treatment from May 2005 to May 2012 were included. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) total score was collected 1, 2, 3, 4, and 5 years after the initial treatment, and the number of patients who underwent total knee arthroplasty (TKA) at every time point was recorded.
Three hundred eighty-two patients (168 in the conservative group and 214 in the arthroscopy group) were included. Five years after the initial treatment, 32 of the 214 patients who underwent arthroscopy (15.0%) compared with 30 of the 168 patients in the conservative treatment group (17.9%) ultimately underwent TKA, with no statistically significant difference between groups (P = .20). The WOMAC score was significantly lower in the arthroscopy group than in the conservative group at year 1 (24.33 ± 21.56 vs 36.43 ± 16.22, respectively) and year 2 (26.31 ± 17.84 vs 35.41 ± 19.21, respectively). There were no significant between-group differences at years 3, 4, and 5.
Compared with conservative treatment, arthroscopy provided no benefit in decreasing or delaying arthroplasty surgery. However, arthroscopy had a greater ability to relieve symptoms at 1 and 2 years. Our results suggest that arthroscopy can relieve symptoms up to 2 years without elevating the risk of arthroplasty.
Level III, retrospective comparative study.
The biodegradable micelles, self-assembled by a reductive poly(β-hydroxyl amine), possess pH and redox dual-responsiveness for intracellular doxorubicin delivery.
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•A kind of cationic ...polymer is prepared by an effective amine-epoxy polymerization.•RPHA polymer contains many hydroxyl groups, disulfide linkages and tertiary amines.•RPHA micelles present the pH and redox dual-responsiveness in solutions.•These biocompatible micelles possess controllable drug release behaviors.•DOX-loaded micelles show a high cellular proliferation inhibition to cancel cells.
Development of multi-responsive biodegradable micellar drug delivery systems for targeted cancer chemotherapy remains a major challenge. Here we demonstrate a kind of pH and reduction dual-responsive cationic polymer via an effective amine–epoxy polymerization, which could self-assemble into the biodegradable micelles in an aqueous solution. On account of the tumor cells or tissues possessing low pH values and high concentrations of reductive agents, these micelles exhibited the specific tumor target ability and maximal drug-release controllability inside tumor cells upon changes in physical and chemical environments, but presented excellent stability at physiological conditions. CCK-8 assay showed that these DOX-loaded micelles had a similar cytotoxicity for MCF-7 tumor cells as the free DOX molecules while blank micelles were low toxic to the cells. Confocal laser scanning microscopy (CLSM) observation revealed that the drug-loaded micelles were quickly internalized by endosomes to effectively restrain the cancer cell growth. These results indicated these biodegradable micelles could be the novel and efficient dual-responsive nanocarriers to improve the drug delivery and enhance the antitumor efficacy.
First-aid for severe traumatic injuries in the battlefield or pre-hospital environment, especially for skin defects or visceral rupture, remains a substantial medical challenge even in the context of ...the rapidly evolving modern medical technology. Hydrogel-based biomaterials are highly anticipated for excellent biocompatibility and bio-functional designability. Yet, inadequate mechanical and bio-adhesion properties limit their clinical application. To address these challenges, a kind of multifunctional hydrogel wound dressing is developed with the collective multi-crosslinking advantages of dynamic covalent bonds, metal-catechol chelation, and hydrogen bonds. The mussel-inspired design and zinc oxide-enhanced cohesion strategy collaboratively reinforce the hydrogel's bio-adhesion in bloody or humoral environments. The pH-sensitive coordinate Zn
-catechol bond and dynamic Schiff base with reversible breakage and reformation equip the hydrogel dressing with excellent self-healing and on-demand removal properties. In vivo evaluation in a rat ventricular perforation model and Methicillin-resistant Staphylococcus aureus (MRSA)-infected full-thickness skin defect model reveal excellent hemostatic, antibacterial and pro-healing effectiveness of the hydrogel dressing, demonstrating its great potential in dealing with severe bleeding and infected full-thickness skin wounds.
Objective:
To analyze the biomechanical effects of proximal iatrogenic muscle-ligaments complex (MLC) damage on adjacent segments following posterior lumbar interbody fusion (PLIF) by finite element ...(FE) analysis.
Methods:
The multifidus muscle force was loaded in the validated intact lumbosacral finite element model. Based on whether undergoing PLIF or the proximal MLC damage, three models were established. Range of motion (ROM) and the maximum von Mises (VM) stress of adjacent segments were analyzed, as well as the average muscle force and work capacity in four loading directions.
Results:
PLIF results in significant changes in ROM and stress. ROM changed significantly in the upper adjacent segment, the PLIF model changed the most in extension, and the largest change in the lower adjacent segment occurred after MLC damage. The VM stress of the upper adjacent segment occurred in extension of the PLIF model, and that of the lower adjacent segment occurred in rotation after MLC damage. In flexion, ROM, and stress of the damaged MLC fusion model were significantly increased compared with the normal and PLIF models, there was a stepwise amplification. The average muscle force comparison of three models was 5.8530, 12.3185, and 13.4670 N, respectively. The total work capacity comparison was close to that of muscle force.
Conclusion:
PLIF results in increased ROM and the VM stress of adjacent segments, the proximal MLC damage will aggravate this change. This may increase the risk of ASD and chronic low back pain. Preserving the proximal MLC reduces the biomechanical effects on adjacent segments.
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