The postoperative clinical effects of utilizing 3D printed (Ti6Al4V) interbody fusion cages in posterior lumbar fusion: A retrospective cohort study.

BACKGROUND: The research focused on the postoperative effect of using interbody fusion cage in lumbar posterior lamina decompression and interbody fusion with pedicle screw by comparing the postoperative effect of using 3D printing (Ti6Al4V) and PEEK material interbody fusion cage. METHODS: Ninety-one patients with lumbar degenerative diseases from the Department of Spine Surgery of Tianjin Hospital were included in the study cohort. They were divided into 3D group (n = 39) and PEEK group (n = 52) according to the use of interbody fusion cage. The imaging data of the patients were collected and the postoperative data of the 2 groups were compared to evaluate patients' health status and the recovery of lumbar structure and function after operation. RESULTS: Combined with the degree of fusion, the clinical effect of 3D printing titanium alloy interbody fusion cage was comprehensively judged. At the last follow-up, the JOA score, ODI index, VAS, prolo function score, and SF-36 scale of the 2 groups showed that the clinical symptoms were better than those before operation (P < .05). The height of intervertebral disc, the area of intervertebral foramen and the physiological curvature of lumbar vertebrae increased in varying degrees after operation (P < .05). At the last follow-up, the vertebral cage fusion rates were as high as 89.13% and 90.91% in the 3D and PEEK groups, with collapse rates of 6.5% and 4.5%, respectively. There were 10 cases of cage displacement in 3D group and 7 cases of cage displacement in PEEK group. There was no significant difference between the 2 groups (P > .05). CONCLUSIONS: In conclusion, 3D printed (Ti6Al4V) interbody fusion cage can obtain good clinical effect in the surgical treatment of lumbar degenerative diseases. Posterior lumbar lamina decompression, bilateral pedicle screw fixation combined with 3D printed cage interbody fusion is excellent in rebuilding the stability of lumbar vertebrae. 3D printed interbody fusion cage can be an ideal substitute material for intervertebral bone grafting. The stable fusion time of interbody fusion cage after lumbar fusion is mostly from 3 months to half a year after operation.

Risk Factors for Residual Back Pain After PVP Treatment for osteoporotic Thoracolumbar Compression Fractures: A Retrospective Cohort Study.

OBJECTIVES: To explore the risk factors of residual back pain after percutaneous vertebroplasty (PVP) in patients with osteoporotic vertebral compression fracture (OVCF). METHODS: We retrospectively reviewed the records of 675 patients with OVCF treated with PVP from January 2015 to January 2020. Postoperative back pain intensity was assessed by the VAS score. Residual back pain was defined as the presence of postoperative moderate-severe pain (average VAS score≥4), and the variables included patient characteristics, baseline symptoms, imaging data and operation-related factors. Risk factors were identified with univariate and multivariate logistic regression analysis. RESULTS: Residual back pain occurred in 46 of the 675 patients included in the study, with an incidence rate of 6.8%. Multivariate logistic regression analysis showed that low Pre-BMD (OR = 3.576, P = 0.041), multiple vertebral fractures (OR = 2.795, P = 0.026), posterior fascia injury (OR = 4.083, P = 0.032), cement diffusion volume rate <0.2 (OR = 3.507, P = 0.013), facet joint violation (OR = 11.204, P < 0.001), and depression (OR = 3.562, P = 0.035) were positively correlated with residual back pain after PVP. CONCLUSIONS: Low pre-BMD (pre-bone mineral density), multiple vertebral fractures, posterior fascia injury, cement diffusion volume rate <0.2, facet joint violation and depression were the independent risk factors of residual back pain after PVP.

Theoretical and experimental investigations on rotary ultrasonic surface micro-machining of brittle materials.

Many brittle materials, such as single-crystal materials, amorphous materials, and ceramics, are widely used in many industries such as the energy industry, aerospace industry, and biomedical industry. In recent years, there is an increasing demand for high-precision micro-machining of these brittle materials to produce precision functional parts. Traditional ultra-precision micro-machining can lead to workpiece cracking, low machined surface quality, and reduced tool life. To reduce and further solve these problems, a new micro-machining process is needed. As one of the nontraditional machining processes, rotary ultrasonic machining is an effective method to reduce the issues generated by traditional machining processes of brittle materials. Therefore, rotary ultrasonic micro-machining (RUµM) is investigated to conduct the surface micro-machining of brittle materials. Due to the small diameter cutting tool (<500 µm) and high accuracy requirements, the impact of input parameters in the rotary ultrasonic surface micro-machining (RUSµM) process on tool deformation and cutting quality is extremely different from that in rotary ultrasonic surface machining (RUSM) with relatively large diameter cutting tool (∼10 mm). Up till now, there is still no investigation on the effects of ultrasonic vibration (UV) and input variables (such as tool rotation speed and depth of cut) on cutting force and machined surface quality in RUSµM of brittle materials. To fill this knowledge gap, rotary ultrasonic surface micro-machining of the silicon wafer (one of the most versatile brittle materials) was conducted in this study. The effects of ultrasonic vibration, tool rotation speed, and depth of cut on tool trajectory, material removal rate (MRR), cutting force, cutting surface quality, and residual stress were investigated. Results show that the ultrasonic vibration could reduce the cutting force, improve the cutting surface quality, and suppress the residual compressive stress, especially under conditions with high tool rotation speed.

Efficient chemoenzymatic synthesis of UDP-α-6-N3-glucose.

A novel chemo-enzymatic synthetic method for UDP-α-6-N3-glucose was developed by combining the versatility of chemical synthesis and natural enzyme stereo-selectivity of Bifidobacterium longum (BLUSP). This flexible and efficient platform expanded the substrate scope for UDP-sugars on an improved scale, particularly for UDP-sugar substrates containing bioorthogonal functional groups.