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Zinc and its alloys are considered to be next-generation materials for fabricating absorbable biomedical devices. However, cytotoxicity has been reported to be associated with rapid degradation. To address these issues, a composite coating (PLA/Li-OCP) consisting of CaHPO 4 conversion coating (Ca-P) and polylactic acid (PLA) decorated with Li-octacalcium phosphate particles was constructed on pure zinc. The immersion tests showed that the presence of Ca-P coating and PLA/Li-OCP coating on pure zinc could reduce the pH value. Compared with Ca-P coating, the introduction of the PLA/Li-OCP film on the Ca-P-coated samples could enhance the corrosion resistance, and there was one order of magnitude decrease in the corrosion current density. The cytocompatibility assay suggested that the PLA/Li-OCP coating favored the cell viability and upregulated the expression of related osteogenic-genes including RUNX2, OCN, and BMP. Therefore, the presence of the PLA/Li-OCP coating on pure zinc could effectively improve the degradation rate and cytocompatibility of pure zinc.

Methylprednisolone sodium phosphate (MP) is an anti-inflammatory corticosteroid which is used in the treatment of spinal cord injury (SCI), however the overdose of MP has toxic effects Therefore it is prerequisite to develop novel approaches to overcome the side effects of MP and enhance its efficacy. In the present work, we have developed alkaline phosphatase (ALP) trigger self-assembly system of oligopeptides to physically entrap and locally deliver MP. The synthesis of Nap-Phe-Phe-Tyr(H2PO3)-OH (1P) was achieved using solid phase peptide synthesis and was characterized using mass spectroscopy. The 1P is a hydrogelator, which in presence of ALP self-assembles to form the hydrogel. During the self-assembly of 1P, MP was physically entrapped without losing the physical strength of hydrogel as revealed in the rheology study. The consistency of this hydrogel and the structure was characterized using circular dichroism. The MP was released from the hydrogel in a sustain manner and 80% of the drug release was observed at 120 h. The MP + 1P were non-toxic to the cells at lower concentration however toxicity increases with the increase in concentration of MP. Further, the in-vivo administration of MP + 1P significantly reduces the pro-inflammatory cytokines and the histological analysis revealed improvement in the SCI. In conclusion, it could be stated that the synthesis of 1P for the delivery of MP provides the novel opportunity in for the treatment of SCI.

Objective To develop a novel semi‐cannulated lateral mass screw (SC‐LMS) for cervical posterior fixations and compare the fixation stability and safety of SC‐LMS with regular solid lateral mass screw (S‐LMS) in bone cement augmentation and pullout strength using fresh cadaveric cervical vertebrae. Methods The conventional multiaxial screw for cervical lateral mass fixation was modified to a cannulated screw with two lateral holes, used for bone cement injection in situ. Eight fresh human cervical vertebrae (C3, C4, and C5) were collected and used. μCT scan was performed to evaluate the bone quality of the lateral masses, including bone mineral density (BMD), trabecular thickness (Tb.Th), and trabecular separation (Tb.Sp). SCLMS or S‐LMS were randomly inserted into the paired cervical vertebrae and pulled out as a screw loosening model. These screws were reinserted in with bone cement augmentation, scanned by μCT to obtain the bone cement distribution along the screws, and pulled out to test the screw purchase strength. Results Fmax values exhibited strong positive correlations with the local BMD (𝑟 = 0.8640, p < 0.0001) and Tb.Th (𝑟 = 0.6795, p = 0.0038), whereas a negative correlation with Tb.Sp (𝑟 = −0.5567, p = 0.0251). A significant difference was observed between the Fmax before and after PMMA injection on the SC‐LMS side (p = 0.019). The SC‐LMS exhibited lower risk of cement leakage than S‐LMS after PMMA injection, and a positive correlation was observed between 𝐹max and the distribution volumes on the SC‐LMS side. Conclusion The novel SC‐LMS provides more robust fixation stability and is safer than the S‐LMS for PMMA augmentation, which may be related to the cement‐screw‐cement‐bone complex formation.

Objective Surgical site infection (SSI) after spinal surgery is still a persistent worldwide health concern as it is a worrying and devastating complication. The number of samples in previous studies is limited and the role of conservative antibiotic therapy has not been established. This study aims to evaluate the clinical efficacy and feasibility of empirical antibiotic treatment for suspected early‐onset deep spinal SSI. Methods We conducted a retrospective study to identify all cases with suspected early‐onset deep SSI after lumbar instrumented surgery between January 2009 and December 2018. We evaluated the potential risks for antibiotic treatment, examined the antibiotic treatment failure rate, and applied logistic regression analysis to assess the risk factors for empirical antibiotic treatment failure. Results Over the past 10 years, 45 patients matched the inclusion criteria. The success rate of antibiotic treatment was 62.2% (28/45). Of the 17 patients who failed antibiotic treatment, 16 were cured after a debridement intervention and the remaining one required removal of the internal fixation before recovery. On univariate analysis, risk factors for antibiotic treatment failure included age, increasing or persisting back pain, wound dehiscence, localized swelling, and time to SSI (cut‐off: 10 days). Multivariate analysis revealed that infection occurring 10 days after primary surgery and wound dehiscence were independent risk factors for antibiotic treatment failure. Conclusion Appropriate antibiotic treatment is an alternative strategy for suspected early‐onset deep SSI after lumbar instrumented surgery. Antibiotic treatment for suspected SSI occurring within 10 days after primary surgery may improve the success rate of antibiotic intervention. Patients with wound dehiscence have a significantly higher likelihood of requiring surgical intervention. Empirical antibiotic treatment is an alternative strategy for suspected early‐onset SSI. Wound dehiscence and infection occurring 10 days after primary surgery were highly suggested for aggressive surgical intervention. Antibiotic treatment prior to surgical debridement did not increase the difficulty of surgical intervention.

Objective This study aimed to investigate the strength of a novel micro‐dynamic pedicle screw by comparing it to the traditional pedicle screw. Methods Forty‐five lumbar vertebrae received a traditional pedicle screw on one side and a micro‐dynamic pedicle screw on the other side as follows (traditional group vs micro‐dynamic group): 15 vertebrae underwent instant pull‐out testing; 15 vertebrae underwent 5000‐cyclic fatigue loading testing; and 15 vertebrae underwent 10,000‐cyclic fatigue loading testing and micro‐computed tomography (micro‐CT) scanning. The peek pull‐out force and normalized peek pull‐out force after instant pull‐out testing, 5000‐cyclic and 10,000‐cyclic fatigue loading testing were recorded to estimate the resistance of two types of screws. Bone mineral density was recorded to investigate the strength of the different screws in osteoporotic patients. And the semidiameter of the screw insertion area on micro‐CT images after fatigue were compared to describe the performance between screw and bone surface. Results The bone mineral density showed a weak correlation with peek pull‐out force (r = 0.252, P = 0.024). The peek pull‐out force of traditional pedicle screw after 10,000‐cyclic fatigue loading were smaller than that of instant pull‐out test in both osteoporotic (P = 0.017) and healthy group (P = 0.029), the peek pull‐out force of micro‐dynamic pedicle screw after 10,000‐cyclic fatigue loading was smaller than that in instant pull‐out test in osteoporotic group (P = 0.033), but no significant difference in healthy group (P = 0.853). The peek pull‐out force in traditional group and micro‐dynamic group underwent instant pull‐out testing (P = 0.485), and pull‐out testing after 5000‐cyclic fatigue loading testing (P = 0.184) did not show significant difference. However, the peek pull‐out force in micro‐dynamic group underwent pull‐test after 10,000‐cyclic fatigue loading testing was significantly greater than that measured in traditional group (P = 0.005). The normalized peek pull‐out force of traditional groups underwent instant pull‐out testing, pull‐out test after 5000‐cyclic and 10,000‐cyclic fatigue loading testing significantly decreased as the number of cycles increased (P < 0.001); meanwhile, the normalized peek pull‐out force of micro‐dynamic groups remained consistent regardless of the number of cycles (P = 0.133). The semidiameter after the fatigue loading test of the traditional screw insertion area was significantly larger than that of the micro‐dynamic screw insertion area (P = 0.013). Conclusion The novel micro‐dynamic pedicle screw provides stronger fixation stability in high‐cyclic fatigue loading and non‐osteoporotic patients versus the traditional pedicle screw, but similar resistance in low‐cycle fatigue testing and osteoporotic group vs the traditional pedicle screw.

PurposeThe aim is to compare the pathogen detection performance of metagenomic next-generation sequencing (mNGS) and the culturing of percutaneous needle biopsy samples obtained from an individual with a suspected spinal infection.MethodsA retrospective study of 141 individuals with a suspected spinal infection was conducted, and mNGS was performed. The microbial spectra and detection performance between mNGS and the culturing-based method were compared, and the effects of antibiotic intervention and biopsy on the detection performance were assessed.ResultsThe microorganisms isolated most commonly via the culturing-based method were Mycobacterium tuberculosis (n = 21), followed by Staphylococcus epidermidis (n = 13). The most common microorganisms detected via mNGS were Mycobacterium tuberculosis complex (MTBC) (n = 39), followed by Staphylococcus aureus (n = 15). The difference in the type of detected microorganisms between culturing and mNGS was observed only in Mycobacterium (P = 0.001). mNGS helped identify potential pathogens in 80.9% of cases, which was significantly higher than the positivity rate of 59.6% observed for the culturing-based method (P < 0.001). Moreover, mNGS had a sensitivity of 85.7% (95% CI, 78.4% to 91.3%), a specificity of 86.7% (95% CI, 59.5% to 98.3%), and sensitivity gains of 35% (85.7% vs. 50.8%; P < 0.001) during culturing, while no differences were observed in the specificity (86.7% vs. 93.3%; P = 0.543). In addition, antibiotic interventions significantly lowered the positivity rate of the culturing-based method (66.0% vs. 45.5%, P = 0.021) but had no effects on the results of mNGS (82.5% vs. 77.3%, P = 0.467).ConclusionThe use of mNGS could result in a higher detection rate compared to that observed with the culturing-based method in an individual with spinal infection and is particularly valuable for evaluating the effects of a mycobacterial infection or previous antibiotic intervention.

This study investigates therapeutic efficacy of photothermal therapy (PTT) in an orthotropic xenograft model of bone metastasis of breast cancer. The near-infrared (NIR) irradiation on Multi-Walled Carbon Nanotubes (MWNTs) resulted in a rapid heat generation which increased with the MWNTs concentration up to 100 μg/ml. MWNTs alone exhibited no toxicity, but inclusion of MWNTs dramatically decreased cell viability when combined with laser irradiation. Thermographic observation revealed that treatment with 10 μg MWNTs followed by NIR laser irradiation resulted in a rapid increase in temperature up to 73.4±11.98 °C in an intraosseous model of bone metastasis of breast cancer. In addition, MWNTs plus NIR laser irradiation caused a remarkably greater suppression of tumor growth compared with treatment with either MWNTs injection or NIR irradiation alone, significantly reducing the amount of tumor-induced bone destruction. All these demonstrate the efficacy of PTT with MWNTs for bone metastasis of breast cancer.

Objectives To describe the morphometry of iliac columns for transiliac screw and to testify the conformity among the anatomic measurement, two-dimensional (2D) and three-dimensional (3D) computed tomography. Methods We evaluated the length, inner width, and angle of three screw trajectories starting at the iliac tubercle, posterior superior iliac spine, and posterior inferior iliac spine toward the anterior inferior iliac spine. Measurements were made on specimen, two- and 3D computed tomography using 18 embalmed cadaveric pelves. Results There was no significant difference among three measure methods. The path between the posterior superior iliac spine and anterior inferior iliac spine had the largest iliac column length, with 135 mm in male and 110 mm in female. The canal allowed placement of 8-mm screw in male and 6.5 mm in female with the angle of 25° laterally directed from the midsagittal plane. The line between the posterior inferior iliac spine and anterior inferior iliac spine was below or just located at the top of greater sciatic notch in the majority measurements. The safe section for transiliac screw approximately located above the greater sciatic notch and could be divided into anterior and posterior parts. Conclusion The measurements among anatomic measurement, 2D and 3D computed tomography are consistent. The screw path from the posterior superior iliac spine toward anterior inferior iliac spine provided the longest anchor site. At the same time, the line between the posterior inferior iliac spine and anterior inferior iliac spine is not available for transiliac screw insertion of eastern population. The posterior of the safe section also can be regarded as another ilium anchorage area for transiliac screws.

Purpose In unique clinical situations where C1–C2 anterior transarticular screw (ATS) fixation is not available or has failed, an anterior transarticular crossing screw (ATCS) with transcorporal pathway of the screws inside the contralateral promontory of C2 may enhance the stabilization and achieve atlantoaxial arthrodesis. The present study was to describe a novel technique of ATCS fixation for atlantoaxial joint instability and its applied anatomy, and compared it with ATS fixation method. Methods Direct measurements using digital calipers and a goniometer were conducted on 30 pairs of dried human C1 and C2 vertebrae. The ATS and ATCS with screws ( Φ 4.0 mm) were performed on 11 fresh cervical spine specimens. The screw lengths in the C1 and C2, and screw entry angles of the ATS and ATCS were measured, respectively. Cadaver specimens were dissected to observe the incidence of violation to the important structures surrounding the ATS and ATCS fixation technique. Results There was enough osseous space for ATCS placement. The lateral and incline angle of the ATCS was 36.2° and 28.7°, respectively. Screw purchase in C2 of the ATCS (25.6 mm) was greater than that of the ATS (11.4 mm). The ATCS C1 purchase (14.8 mm) was similar to the ATS C1 purchase (14.9 mm). No violation to the vertebral artery groove, the spinal canal or the atlanto-occipital joint was observed after the ATCS placement. Conclusion Anterior transarticular crossing screw is a feasible and viable option for atlantoaxial fixation in selected cases. This technique achieved remarkable longer screw purchase and could enhance the atlantoaxial stability.