Objective: Mitochondrial dysfunction, oxidative stress and nucleus pulposus (NP) cell apoptosis are important contributors to the development and pathogenesis of intervertebral disc degeneration (IDD). Here, we comprehensively evaluated the effects of mitochondrial dynamics, mitophagic flux and Nrf2 signalling on the mitochondrial quality control, ROS production and NP cell survival in in vitro and ex vivo compression models of IDD and explored the effects of the mitochondria‐targeted anti‐oxidant MitoQ and its mechanism.Material and methods: Human NP cells were exposed to mechanical compression to mimic pathological conditions.Results: Compression promoted oxidative stress, mitochondrial dysfunction and NP cell apoptosis. Mechanistically, compression disrupted the mitochondrial fission/fusion balance, inducing fatal fission. Concomitantly, PINK1/Parkin‐mediated mitophagy was activated, whereas mitophagic flux was blocked. Nrf2 anti‐oxidant pathway was insufficiently activated. These caused the damaged mitochondria accumulation and persistent oxidative damage. Moreover, MitoQ restored the mitochondrial dynamics balance, alleviated the impairment of mitophagosome‐lysosome fusion and lysosomal function and enhanced the Nrf2 activity. Consequently, damaged mitochondria were eliminated, redox balance was improved, and cell survival increased. Additionally, MitoQ alleviated IDD in an ex vivo rat compression model.Conclusions: These findings suggest that comodulation of mitochondrial dynamics, mitophagic flux and Nrf2 signalling alleviates sustained mitochondrial dysfunction and oxidative stress and represents a promising therapeutic strategy for IDD; furthermore, our results provide evidence that MitoQ might serve as an effective therapeutic agent for this disorder.

Objective: To determine whether more precise cup positioning can be achieved with robot‐assisted total hip arthroplasty (THA) as compared to conventional THA.Methods: In this study, between July 2019 and May 2021, 93 patients aged 23–75 years with osteonecrosis of the femoral head (ONFH) and adult developmental dysplasia of hip who underwent first hip surgery were included in the study. They were randomly assigned to either the robotic‐assisted THA group (n = 45) or the conventional THA group (n = 48). After the operation, all patients were given routine rapid rehabilitation guidance. The duration of operation was recorded to estimate the learning curve through cumulative summation analysis. We compared the demographics, duration of operation, cup positioning, leg length discrepancy, hip offset, and Harris Hip Score between robot‐assisted THA and manual THA. Precision in the positioning of the acetabular prosthesis using the MAKO system was also compared between the two groups.Results: The mean duration of operation for the robot‐assisted THA group was 91.37 ± 17.34 min (range: 63 to 135 min), which was significantly higher than that for the conventional THA group. When the number of procedures was increased to 13, the duration of operation in the robot‐assisted group decreased significantly and gradually became stable. In terms of duration of operation, robot‐assisted THA was associated with a learning curve of 13 cases. The mean amount of bleeding in the robot‐assisted THA group was not significantly different from that in conventional THA group (328 ± 210 ml vs 315 ± 205 ml) (p = 0.741). There was no significant difference in the proportion of prostheses located within Lewinnek's safe zone between robot‐assisted THA group and conventional THA group (69.81% vs 64.41%). The leg length discrepancy (LLD) was significantly smaller in the robot‐assisted THA group than in the conventional THA group (p < 0.001), but both were within acceptable limits (10 mm). The inclination and anteversion angles of the acetabular prosthesis planned before operations were correlated with the actual measurement (r = 0.857 p < 0.001, r = 0.830, p < 0.001). After surgery, none of the patients experienced hip dislocation, aseptic loosening, or periprosthetic infection during the 3 months of follow‐up.Conclusion: The proportion of acetabular prostheses in the Lewinnek's safety zone was higher and the extent of LLD was significantly lower in the robot‐assisted THA group, as compared to the same metrics in the conventional THA group. The MAKO robot improved the accuracy of implant placement in THA.

Physiological studies in humans proved that the central nervous system automatically integrates the information from different sensory systems. Inspired by the integration mechanism, this study aims to yield accurate perception of the surgical field during milling operation. The dynamic model of surgical milling process is developed theoretically, and the model considers the influence of the unbalance in the rotating machine and the time-variant cutting force. On the basic of the theoretical analysis, the monitoring of the milling process can be realized to determine the state of the operation. An accelerometer and a microphone are used to measure the acceleration of the milling device and the sound pressure generated during bone milling separately, and then the correlation coefficient between the harmonics in the two signals is fed into the artificial neural network. The output of the artificial neural network is used to determine whether the milling device is cutting the cortical bone, the cancellous bone, the muscle or nothing (i.e. idle running). The experimental results in in vitro porcine spines show that the proposed method is very sensitive to the phenomenon of tissue wrapping in the surgical field, and it can identify the predetermined states correctly.

Cervical spondylotic myelopathy (CSM) is a common disease of the elderly that is characterized by gait instability, sensorimotor deficits, etc. Recurrent symptoms including memory loss, poor attention, etc. have also been reported in recent studies. However, these have been rarely investigated in CSM patients. To investigate the cognitive deficits and their correlation with brain functional alterations, we conducted resting-state fMRI (rs-fMRI) signal variability. This is a novel indicator in the neuroimaging field for assessing the regional neural activity in CSM patients. Further, to explore the network changes in patients, functional connectivity (FC) and graph theory analyses were performed. Compared with the controls, the signal variabilities were significantly lower in the widespread brain regions especially at the default mode network (DMN), visual network, and somatosensory network. The altered inferior parietal lobule signal variability positively correlated with the cognitive function level. Moreover, the FC and the global efficiency of DMN increased in patients with CSM and positively correlated with the cognitive function level. According to the study results, (1) the cervical spondylotic myelopathy patients exhibited regional neural impairments, which correlated with the severity of cognitive deficits in the DMN brain regions, and (2) the increased FC and global efficiency of DMN can compensate for the regional impairment.