Objective To evaluate the correction rate,accuracy of pedicle screw fixation and overall clinical efficacy of intravertebral osteotomy and internal fixation surgery with the assistance of 3D printing guide plates in treatment of severe kyphosis.Methods A single-center nonrandomized clinical pilot study was conducted on 19 patients(8 males and 11 females)with severe kyphosis undergoing intravertebral osteotomy between December 2018 and June 2023.Seven of them(CAD group)had preoperative planning with computer-aided design(CAD)and intraoperative guidance of individualized 3D printing guide plates.And another 12 patients(control group)were corrected with conventional pedicle screw placement.Postoperative evaluation included assessment of posterior Cobb angle,spinal angular correction rate,accuracy of pedicle screw placement and Oswestry Dysfunction Index(ODI)questionnaire.Results The 19 patients were at a mean age of 48.0 years,and followed up for 26.4(9～54)months.All of them achieved relatively satisfactory corrective results,with those of the CAD group having a correction rate of 96.83％and those of the control group of 86.61％.There were no statistical differences in average intraoperative blood loss(857 vs 1 045 mL)and average operative time(344 vs 402 min),but significant difference was observed in average length of hospital stay(11 vs 18 d,P＜0.05)between the 2 groups.A total of 278 nails were placed in this study,including 70 guide-assisted pedicle screws,97.1％of which were grade A or B.In the control group,208 pedicle screws were placed,93.8％of which were grade A or B.Postoperative CT/X-ray scanning displayed that both groups achieved certain correction for kyphosis.No obvious difference was found in the average spinal angular correction(43.37° vs 36.10°),and significantly higher correction rate was seen in the CAD group than the control group(96.83％vs 86.61％,P＜0.01).The ODI value was notably lower in the CAD group than the control group(P＜0.05).Conclusion CAD-assisted preoperative planning,surgical simulation and individualized 3D printing guide plates can promote surgical correction and accuracy of pedicle screw placement and improves the quality of life of patients with severe kyphotic deformity.

The mammalian central nervous system (CNS) is considered an immune privileged system as it is separated from the periphery by the blood brain barrier (BBB). Yet, immune functions have been postulated to heavily influence the functional state of the CNS, especially after injury or during neurodegeneration. There is controversy regarding whether adaptive immune responses are beneficial or detrimental to CNS injury repair. In this study, we utilized immunocompromised SCID mice and subjected them to spinal cord injury (SCI). We analyzed motor function, electrophysiology, histochemistry, and performed unbiased RNA-sequencing. SCID mice displayed improved CNS functional recovery compared to WT mice after SCI. Weighted gene-coexpression network analysis (WGCNA) of spinal cord transcriptomes revealed that SCID mice had reduced expression of immune function-related genes and heightened expression of neural transmission-related genes after SCI, which was confirmed by immunohistochemical analysis and was consistent with better functional recovery. Transcriptomic analyses also indicated heightened expression of neurotransmission-related genes before injury in SCID mice, suggesting that a steady state of immune-deficiency potentially led to CNS hyper-connectivity. Consequently, SCID mice without injury demonstrated worse performance in Morris water maze test. Taken together, not only reduced inflammation after injury but also dampened steady-state immune function without injury heightened the neurotransmission program, resulting in better or worse behavioral outcomes respectively. This study revealed the intricate relationship between immune and nervous systems, raising the possibility for therapeutic manipulation of neural function via immune modulation.