Hapln1 promotes dedifferentiation and proliferation of iPSC-derived cardiomyocytes by promoting versican-based GDF11 trapping.

Hyaluronan and proteoglycan link protein 1 (Hapln1) supports active cardiomyogenesis in zebrafish hearts, but its regulation in mammal cardiomyocytes is unclear. This study aimed to explore the potential regulation of Hapln1 in the dedifferentiation and proliferation of cardiomyocytes and its therapeutic value in myocardial infarction with human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) and an adult mouse model of myocardial infarction. HiPSC-CMs and adult mice with myocardial infarction were used as in vitro and in vivo models, respectively. Previous single-cell RNA sequencing data were retrieved for bioinformatic exploration. The results showed that recombinant human Hapln1 (rhHapln1) promotes the proliferation of hiPSC-CMs in a dose-dependent manner. As a physical binding protein of Hapln1, versican interacted with Nodal growth differentiation factor (NODAL) and growth differentiation factor 11 (GDF11). GDF11, but not NODAL, was expressed by hiPSC-CMs. GDF11 expression was unaffected by rhHapln1 treatment. However, this molecule was required for rhHapln1-mediated activation of the transforming growth factor (TGF)-ß/Drosophila mothers against decapentaplegic protein (SMAD)2/3 signaling in hiPSC-CMs, which stimulates cell dedifferentiation and proliferation. Recombinant mouse Hapln1 (rmHapln1) could induce cardiac regeneration in the adult mouse model of myocardial infarction. In addition, rmHapln1 induced hiPSC-CM proliferation. In conclusion, Hapln1 can stimulate the dedifferentiation and proliferation of iPSC-derived cardiomyocytes by promoting versican-based GDF11 trapping and subsequent activation of the TGF-ß/SMAD2/3 signaling pathway. Hapln1 might be an effective hiPSC-CM dedifferentiation and proliferation agent and a potential reagent for repairing damaged hearts.

Avulsion fracture of the anterior superior iliac crest following autograft for anterior lumbar fusion: case report and literature review.

Avulsion fracture of the anterior superior iliac crest (ASIC) following autogenous bone grafting for anterior lumbar fusion (ALF) is an extremely rare complication. We describe a very rare case of avulsion fracture of the ASIC following autograft for ALF in a revision surgery for treating lumbar tuberculosis. A 68-year-old woman with lumbar tuberculosis underwent posterior debridement and posterior iliac crest bone graft fusion; however, her lumbar tuberculosis recurred 9 months after surgery. She then underwent a lumbar revision surgery, including removal of the posterior instrumentation and debridement, followed by anterior L2 corpectomy, debridement, anterior left iliac crest bone graft fusion, and internal fixation. When walking for the first time on postoperative day 3, she experienced a sharp, sudden-onset pain in the anterior iliac crest harvest area. X-ray revealed an avulsion fracture of the ASIC. Considering her failure to respond to conservative treatment for one week and large displacement of the fracture ends, an open reduction and internal fixation surgery was scheduled. Her pain symptoms were significantly relieved after the operation. Although rare, fracture of the ASIC following autograft for ALF should not be ignored. Fracture of the ASIC is usually treated conservatively. Additional surgical treatment is required only when intractable pain fails to respond to conservative treatment or when there is a large displacement of fracture ends that are not expected to heal spontaneously.

Mechanical bone strength decreases considerably after microwave ablation-Ex-vivo and in-vivo analysis in sheep long bones.

BACKGROUND: Bone metastases are on the rise due to longer survival of cancer patients. Local tumor control is required for pain relief. Microwave ablation (MWA) is a technique for minimally invasive local tumor treatment. Tumor tissue is destroyed by application of local hyperthermia to induce necrosis. Given the most common setting of palliative care, it is generally considered beneficial for patients to start mobilizing directly following treatment. No data on mechanical strength in long bones after MWA have been published so far. MATERIALS AND METHODS: In- and ex-vivo experiments on sheep tibias were performed with MWA in various combinations of settings for time and power. During the in-vivo part sheep were sacrificed one or six weeks after ablation. Mechanical strength was examined with a three-point bending test for ablations in the diaphysis and with an indentation test for ablations in the metaphysis. RESULTS: MWA does not decrease mechanical strength in the diaphysis. In the metaphysis strength decreased up to 50% six weeks after ablation, which was not seen directly after ablation. CONCLUSION: MWA appears to decrease mechanical strength in long bone metaphysis up to 50% after six weeks, however strength remains sufficient for direct mobilization. The time before normal strength is regained after the remodeling phase is not known.

Roles of p38 MAPK signalling in intervertebral disc degeneration.

Intervertebral disc degeneration (IVDD) is a common degenerative disease mediated by multiple factors. Because of its complex aetiology and pathology, no specific molecular mechanisms have yet been identified and no definitive treatments are currently available for IVDD. p38 mitogen-activated protein kinase (MAPK) signalling, part of the serine and threonine (Ser/Thr) protein kinases family, is associated with the progression of IVDD, by mediating the inflammatory response, increasing extracellular matrix (ECM) degradation, promoting cell apoptosis and senescence and suppressing cell proliferation and autophagy. Meanwhile, the inhibition of p38 MAPK signalling has a significant effect on IVDD treatment. In this review, we first summarize the regulation of p38 MAPK signalling and then highlight the changes in the expression of p38 MAPK signalling and their impact on pathological process of IVDD. Moreover, we discuss the current applications and future prospects of p38 MAPK as a therapeutic target for IVDD treatment.

Does the Choice of Operative Side Affect the Clinical Outcome of Unilateral Percutaneous Kyphoplasty for Osteoporotic Vertebral Compression Fracture?

BACKGROUND: Studies have found that the rate of improvement in pain after percutaneous kyphoplasty (PKP) is 49% to 90%, and there are still some patients who may continue to sustain intractable back pain after surgery. OBJECTIVES: To compare the clinical efficacy and imaging results between unilateral PKP performed from the symptom-dominating side and the non-dominating side in OVCF treatment. STUDY DESIGN: Prospective study. SETTING: All data were from Honghui Hospital in Xi'an. METHODS: One hundred forty-two patients of osteoporotic vertebral compression fracture (OVCF) treated with unilateral PKP were eventually recruited and randomly assigned to either the A or B group. Patients in group A received PKP from the symptom-dominating side; patients in group B received PKP from the symptom non-dominating side. The demographic characteristics, related surgical information, and complications observed within both groups were recorded. The clinical outcomes evaluation included the visual analog scale (VAS) score for low back pain and the Oswestry Disability Index (ODI). Evaluation of imaging results included anterior height (AH), kyphosis angulation (KA), and contralateral distribution rate of bone cement. RESULTS: One hundred eighteen patients (48 men and 70 women; age range: 60-83 years), including 59 patients in the A group and 59 patients in the B group, were available for the complete assessment. There were 5 cases and 7 cases of bone cement leakage in groups A and B, respectively, which were asymptomatic para-vertebral or inter-vertebral leakage without intra-spinal leakage. Compared with the preoperative data, significant improvements in the VAS scores and ODI were observed at each follow-up interval. The VAS score and ODI in the A group were significantly lower than in the B group only within 2 months (P < 0.05). Compared with the preoperative data, the AH and KA in the 2 groups were improved (P < 0.05). There was no significant difference in AH and KA between the 2 groups at each follow-up interval (P > 0.05). LIMITATIONS: A single-center study. CONCLUSIONS: The unilateral PKP performed via the symptom-dominating side can effectively relieve back pain and improve the patient's quality of life at the early stage.

Screw Pullout Strength After Pedicle Screw Reposition: A Finite Element Analysis.

RESEARCH DESIGN: Finite element analysis based on computed tomography images from the lumbar spine. OBJECTIVE: Determined the pullout strength of unsatisfactorily placed screws and repositioned screws after unsatisfactory place in lumbar spine surgery. BACKGROUND: Pedicle screws are widely used to stabilize the spinal vertebral body. Unsatisfactory screws could lead to surgical complications, and may need to be repositioned. Screw removal and reposition, however, may decrease pullout strength. METHODS: We conducted a three-dimensional finite element analysis based on high-resolution computed tomography images from a 39-year-old healthy woman. Pullout strength was determined with the screw placed in different orientations at the same entry point (as selected by the Magerl method), as well as after removal and reposition. The material properties of the vertebral body and the screw were simulated by using grayscale values and verified data, respectively. A load along the screw axis was applied to the end of the screw to simulate the pullout. RESULTS: The pullout strength was 1840.0 N with the Magerl method. For unsatisfactorily placed screws, the pullout strength was 1500.8 N at 20% overlap, 1609.6 N at 40% overlap, 1628.9 N at 60% overlap, and 1734.7 N at 80% overlap with the hypothetical screw path of the Magerl method. For repositioned screws, the pullout strength was 1763.6 N, with 20% overlap, 1728.3 N at 40% overlap, 1544.0 N at 60% overlap, and 1491.1 N at 80% overlap, with the original path. Comparison of repositioned screw with unsatisfactorily placed screw showed 14.04% decrease in pullout strength at 80% overlap, 5.21% decrease at 60% overlap, 7.37% increase at 40% overlap, and 17.51% increase at 20% overlap, with the screw path of the Magerl method. CONCLUSIONS: Removal and reposition increased the pullout strength at 20% and 40% overlap, but decreased the pullout strength at 60% and 80% overlap. For clinical translation, we recommend removal and reposition of the screw when the overlap is in the range of 20% to 40% or less. In vitro specimen studies are needed to verify these preliminary findings.

OECs Prevented Neuronal Cells from Apoptosis Partially Through Exosome-derived BDNF.

It is known that neurotrophic factors are a major source of the neuroprotective effects of olfactory ensheathing cells (OECs). However, the form of neurotrophic factors that originate from OECs is not fully understood. Our previous study demonstrated that OECs could secrete exosome (OECs-Exo), which provided neuroprotection by switching the phenotype of macrophages/microglia. Considering that exosomes could also be taken up by neurons, we explored the direct effect of OECs-Exo on neuronal survival and the underlying mechanism. Electron microscopy, nano-traffic analysis, and Western blotting were applied to identify the OECs-Exo. The effect of OECs-Exo on neuronal survival was tested by flow cytometry and TUNEL staining. Western blotting and ELISA were used to detect neurotrophic factors in purified OECs-Exo. We first isolated OECs-Exo and found that OECs-Exo exerted protective effects on neuronal survival in response to TNF-α challenge. Brain-derived neurotrophic factor (BDNF) was then identified in OECs-Exo, and its receptor TrkB in neurons was activated by OECs-Exo treatment. Furthermore, we demonstrated that OECs prevented TNF-α-induced apoptosis in neurons partially through exosome-derived BDNF. Our data showed that OECs attenuated TNF-α-induced apoptosis in neurons partially through OEC-Exo-derived BDNF, which might provide a novel strategy for the neuroprotective effect of OEC-Exo-based treatment.

Bioprinting for bone tissue engineering.

The shape transformation characteristics of four-dimensional (4D)-printed bone structures can meet the individual bone regeneration needs, while their structure can be programmed to cross-link or reassemble by stimulating responsive materials. At the same time, it can be used to design vascularized bone structures that help establish a bionic microenvironment, thus influencing cellular behavior and enhancing stem cell differentiation in the postprinting phase. These developments significantly improve conventional three-dimensional (3D)-printed bone structures with enhanced functional adaptability, providing theoretical support to fabricate bone structures to adapt to defective areas dynamically. The printing inks used are stimulus-responsive materials that enable spatiotemporal distribution, maintenance of bioactivity and cellular release for bone, vascular and neural tissue regeneration. This paper discusses the limitations of current bone defect therapies, 4D printing materials used to stimulate bone tissue engineering (e.g., hydrogels), the printing process, the printing classification and their value for clinical applications. We focus on summarizing the technical challenges faced to provide novel therapeutic implications for bone defect repair.

lncRNA HHIP-AS1/HHIP modulates osteogenic differentiation of BM-MSCs by regulating Hedgehog signaling pathway.

BACKGROUND: lncRNA, a type of non-coding RNA, plays an important role in the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BM-MSCs). In this study, lncRNA and mRNA microarrays were performed to study the change of gene expression during osteogenic differentiation of BM-MSCs. We focused on Hedgehog interacting protein (HHIP), because HHIP mRNA and lncRNA HHIP-AS1 were gradually down-regulated on days 0, 7, and 14 during osteogenic differentiation. In addition, the gene coding lncRNA HHIP-AS1 is located on the anti-sense of Hhip gene, implying the potential interaction between lncRNA HHIP-AS1 and HHIP mRNA. METHODS: BM-MSCs with over-expressed or silenced lncRNA HHIP-AS1 were constructed to explore the biological role of HHIP-AS1 in osteogenic differentiation. BM-MSCs were lysed to determine the alkaline phosphatase activity. Fluorescence in situ hybridization and immunofluorescence were performed to analyze HHIP-AS1, HHIP, RUNX2 and osteocalcin. RESULTS: Overexpression of lncRNA HHIP-AS1 increased HHIP expression, which suppressed Hedgehog signaling pathway, as indicated by the reduction of SMO, Gli1 and Gli2. The suppression of Hedgehog signal was associated with the inhibited osteogenesis. HHIP knockdown abolished the suppression of osteogenesis induced by lncRNA HHIP-AS1 overexpression. Through binding to HHIP mRNA, lncRNA HHIP-AS1 recruited ELAVL1 to HHIP mRNA, whereby increasing the mRNA stability and the protein level. CONCLUSIONS: This study revealed that down-regulation of HHIP due to lncRNA HHIP-AS1 reduction promoted the osteogenic differentiation of BM-MSCs though removing the suppression of Hedgehog signal.

Necroptosis of nucleus pulposus cells involved in intervertebral disc degeneration through MyD88 signaling.

Background context: Low back pain, affecting nearly 40% of adults, mainly results from intervertebral disc degeneration (IVDD), while the pathogenesis of IVDD is still not fully elucidated. Recently, some researches have revealed that necroptosis, a programmed necrosis, participated in the progression of IVDD, nevertheless, the underlying mechanism remains unclear. Purpose: To study the mechanism of necroptosis of Nucleus Pulposus (NP) cells in IVDD, focusing on the role of MyD88 signaling. Study design: The expression and co-localization of necroptotic indicators and MyD88 were examined in vivo, and MyD88 inhibitor was applied to determine the role of MyD88 signaling in necroptosis of NP cells in vitro. Methods: Human disc specimens were collected from patients receiving diskectomy for lumbar disc herniation (LDH) or traumatic lumbar fractures after MRI scanning. According to the Pfirrmann grades, they were divided into normal (Grades 1, 2) and degenerated groups (4, 5). Tissue slides were prepared for immunofluorescence to assess the co-localization of necroptotic indicators (RIP3, MLKL, p-MLKL) and MyD88 histologically. The combination of TNFα, LPS and Z-VAD-FMK was applied to induce necroptosis of NP cells. Level of ATP, reactive oxygen species (ROS), live-cell staining and electron microscope study were employed to study the role of MyD88 signaling in necroptosis of NP cells. Results: In vivo, the increased expression and co-localization of necroptotic indicators (RIP3, MLKL, p-MLKL) and MyD88 were found in NP cells of degenerated disc, while very l low fluorescence intensity in tissue of traumatic lumbar fractures. In vitro, the MyD88 inhibitor effectively rescued the necroptosis of NP cells, accompanied by increased viability, ATP level, and decreased ROS level. The effect of MyD88 inhibition on necroptosis of NP cells was further confirmed by ultrastructure of mitochondria shown by Transmission Electron Microscope (TEM). Conclusion: Our results indicated that the involvement of MyD88 signaling in the necroptosis of NP cells in IVDD, which will replenish the pathogenesis of IVDD and provide a novel potential therapeutic target for IVDD.

Clinical Efficacy and Safety of Surgical Treatments in Patients With Pure Cervical Radiculopathy.

Background: Traditionally paired meta-analysis revealed inconsistencies in the safety and effectiveness of surgical interventions. We conducted a network meta-analysis to assess various treatments' clinical efficacy and safety for pure cervical radiculopathy. Methods: The Embase, PubMed, and Cochrane Library databases were searched for randomized controlled trials (RCTs) comparing different treatment options for patients with pure cervical radiculopathy from inception until October 23, 2021. The primary outcomes were postoperative success rates, postoperative complication rates, and postoperative reoperation rates. The pooled data were subjected to a random-effects consistency model. The protocol was published in PROSPERO (CRD42021284819). Results: This study included 23 RCTs (n = 1,844) that evaluated various treatments for patients with pure cervical radiculopathy. There were no statistical differences between treatments in the consistency model in terms of major clinical effectiveness and safety outcomes. Postoperative success rates were higher for anterior cervical foraminotomy (ACF: probability 38%), posterior cervical foraminotomy (PCF: 24%), and anterior cervical discectomy with fusion and additional plating (ACDFP: 21%). Postoperative complication rates ranked from high to low as follows: cervical disc replacement (CDR: probability 32%), physiotherapy (25%), ACF (25%). Autologous bone graft (ABG) had better relief from arm pain (probability 71%) and neck disability (71%). Among the seven surgical interventions with a statistical difference, anterior cervical discectomy with allograft bone graft plus plating (ABGP) had the shortest surgery time. Conclusions: According to current results, all surgical interventions can achieve satisfactory results, and there are no statistically significant differences. As a result, based on their strengths and patient-related factors, surgeons can exercise discretion in determining the appropriate surgical intervention for pure cervical radiculopathy.Systematic Review Registration: CRD42021284819.

Risk factors for proximal junctional kyphosis after posterior long-segment internal fixation for chronic symptomatic osteoporotic thoracolumbar fractures with kyphosis.

BACKGROUND: This study aimed to analyze the risk factors for proximal junctional kyphosis (PJK) for patients with chronic symptomatic osteoporotic thoracolumbar fractures (CSOTLF) and kyphosis who underwent long-segment internal fixation. METHODS: We retrospectively reviewed the records of patients with CSOTLF complicated with kyphosis who underwent posterior multilevel internal fixation in our hospital between January 2013 and January 2020. The patients' age, sex, body mass index (BMI), bone mineral density (BMD), smoking status, cause of injury, comorbidities, injury segments, and American Spinal Injury Association (ASIA) grading non-surgical data; posterior ligament complex (PLC) injury, upper and lower instrumented vertebral position (UIV and LIV, respectively), number of fixed segments surgical data, proximal junctional angle (PJA), sagittal vertebral axis (SVA), pelvic incidence (PI), lumbar lordosis (LL), pelvic incidence-lumbar lordosis mismatch (PI-LL), pelvic tilt (PT), and sacral slope (SS) surgical indicators were collected. Patients were divided into postoperative PJK and non-PJK groups. RESULTS: This study included 90 patients; among them, 30 (31.58%) developed PJK postoperatively. All patients were followed up for > 24 months (mean 32.5 months). Univariate analysis showed significant differences in age, BMI, BMD, PLC injury, UIV, and LIV fixation position, number of fixation stages, and preoperative PJA, SVA, PI-LL, and SS between the two groups (P < 0.05). Additionally, no significant differences were observed in sex, smoking, cause of injury, complications, injury segment ASIA grade, and preoperative PT between the two groups (P > 0.05). Multifactorial logistic regression analysis showed that age > 70 years (OR = 32.279, P < 0.05), BMI > 28 kg/m2 (OR = 7.876, P < 0.05), BMD T value < - 3.5 SD (OR = 20.836, P < 0.05), PLC injury (OR = 13.981, P < 0.05), and preoperative PI-LL > 20° (OR = 13.301, P < 0.05) were risk factors for PJK after posterior long-segment internal fixation in elderly patients with CSOTLF complicated with kyphosis. CONCLUSION: CSOTLF patients undergoing posterior long segment internal fixation are prone to PJK, and age > 70 years, BMI > 28 kg/m2, BMD T value < - 3.5 SD, preoperative PI-LL > 20° and PLC injury may increase their risk.

RP11-867G2.8 promotes EMT and chordoma malignant phenotypes by enhancing FUT4 mRNA stability and translation.

Chordoma is a rare bone tumor, and the recurrence rate of chordoma is high, the treatment is difficult, and the prognosis is poor. Therefore, it is of great significance to find key target genes for the treatment of chordoma. Microarray was used to analyze the significant gene associated with chordoma. Western blot and RT-PCR were used to detect protein and mRNA expression levels of RP11-867G2.8 and FUT4. Fluorescence in situ hybridization (FISH) assay was used to locate the position of RP11-867G2.8 in chordoma cells. MTT assay, colony formation assay, transwell assay and Xenograft Mouse Model were used to clarify the function of RP11-867G2.8 and FUT4. RNA pull-down, RNA immunoprecipitation, RNA stability assay and polysome profiling analysis were used to clarify the relationship between RP11-867G2.8 and FUT4. We found that RP11-867G2.8 is highly expressed in chordoma tissues and cells, and RP11-867G2.8 overexpression promotes the malignant biological behavior of chordoma cells. RP11-867G2.8 overexpression alters the expression pattern of genes modulating signaling pathway. FUT4 is accumulated in chordoma tissues, and RP11-867G2.8 is antisense RNA of FUT4. RP11-867G2.8 can bind to FUT4 mRNA, increasing FUT4 mRNA stability and facilitating translation of FUT4. RP11-867G2.8 binds to EIF4B and PABPC1, which increases the translation of FUT4. Further studies found that FUT4 silence counteracts the effect of RP11-867G2.8 in vivo and in vitro. Our results suggest that RP11-867G2.8 promotes the development and progression of chordoma by up-regulating the expression of FUT4.

Surgical treatment of the lower cervical brucellosis with osteoporosis in the northwest region of China: review of 22 cases.

OBJECTIVE: To analyze the surgical treatment of patients with cervical brucellosis with osteoporosis over a 4-year period in Northwest China. METHODS: From 2013 to 2018, 22 patients (12 males and 10 females) with lower cervical spine brucellosis (C3-C7) underwent anterior lesion debridement, decompression, bone grafting and internal fixation combined with posterior bone graft fusion and internal fixation (ADDF+PIF). The follow-up period averaged 37.4 months (ranging from 24 to 57 months). RESULTS: Involvement of 1 vertebra was observed in 3 patients, involvement of 3 vertebrae was observed in 9 patients, and involvement of 3 vertebrae was observed in 10 patients. Before surgery, 1 patient had Frankel grade B, 2 had grade C, 9 had grade D, and 10 had grade E. In the final follow-up, 12 patients had neurological deficits, 10 patients improved by one grade, 6 patients improved by two grades, and the neurological status of 6 patients remained unchanged. In all cases, it was observed that bone fusion required 6.8 months on average. The kyphosis Cobb angle was enhanced from an average of 11.5° preoperatively (range 0°-24°) to 0.13° postoperatively (range 1°-5°), and there was no vital loss of correction in the follow-up. CONCLUSIONS: ADDF+PIF is an effective and safe treatment for patients with lower cervical brucellosis with osteoporosis.

[A case-control study of minimally invasive transforaminal interbody fusion with the assistance of robot and traditional fluoroscopy in the treatment of single-space lumbar disc herniation].

OBJECTIVE: To compare the safety and nail placement accuracy of fluoroscopy-assisted and robot-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of single-space lumbar disc herniation. METHODS: The clinical data of 52 patients with single-space lumbar disc herniation treated by MIS-TLIF from March 2019 to February 2020 were retrospectively analyzed. Among them, 24 patients were treated by robot-assisted MIS-TLIF(group A) and 28 patients were treated by fluoroscopy-assisted MIS-TLIF (group B). The intraoperative blood loss, operation time, intraoperative fluoroscopy times, preoperative and postoperative visual analogue scale(VAS), Japanese Orthopaedic Association(JOA) scores and operation-related complications were recorded in two groups. Gertzbein-Robbins grade according to CT scan was used to evaluate the nail placement after operation. Grade A and B were evaluated as satisfactory nail placement, and grade C, D, and E were evaluated as error placement. Babu's method was used to evaluate the screw's invasion to the superior articular process. RESULTS: The operation time, intraoperative blood loss and intraoperative fluoroscopy times in group A were less than those in group B(P<0.05).VAS and JOA scores of all patients at the final follow-up were significantly improved compared with those before operation(P<0.05), but there was no statistically significant difference between the groups(P>0.05). There were 96 and 112 screws in group A and group B, respectively. Three days after operation, according to the Gertzbein-Robbins grade to evaluate the nail placement accuracy, there were 90 screws of grade A, 5 of grade B, 1 of grade C, no grade D and E in group A;there were 84 screws of grade A, 16 of grade B, 8 of grade C, 4 of grade D, no grade E in group B;the difference between two groups was statistically significant(Z=-3.709, P=0.000). The satisfactory rate of screw placement in group A was 98.96% (95/96), and that of group B was 89.29% (100/112), the difference between two groups was statistically significant (χ2=8.254, P=0.004). Three days after operation, the invasion of superior facet joints by pedicle screws was evaluated according to Babu's method, including 90 screws in grade 0, 4 in grade 1, 2 in grade 2, and 0 in grade 3 in group A;86 in grade 0, 12 in grade 1, 10 in grade 2 and 4 in grade 3 in group B, and the difference was statistically significant(Z=-3.433, P=0.001). There were no serious spinal cord, nerve and vascular injuries and other operation-related complications caused by screw implantation failure in both groups. All patients were followed up from 6 to 12(9.06±1.60) months. The neurological symptoms improved well after operation. During the follow-up period, there was no recurrence of symptoms, loosening or breakage of the internal fixation. CONCLUSION: Compared with the traditional fluoroscopy-assisted MIS-TLIF, the spinal robot-assisted MIS-TLIF not only has more minimally invasive and safer, but also has higher accuracy in nail placement, lower incidence of upper articular process invasion, and more accurate decompression targets, which can be used for minimally invasive treatment of single-space lumbar disc herniation.

Comparison of degenerative lumbar spondylolisthesis and isthmic lumbar spondylolisthesis: effect of pedicle screw placement on proximal facet invasion in surgical treatment.

BACKGROUND: Pedicle screw invasion of the proximal articular process will cause local articular process degeneration and acceleration, which is an important factor affecting adjacent segment degeneration. Although lumbar spondylolisthesis is a risk factor for screw invasion of the proximal joint, there is no clear conclusion regarding the two different types of spondylolisthesis. Therefore, the purpose of this study was to explore the influence of pedicle screw placement on proximal facet invasion in the treatment of degenerative spondylolisthesis and isthmic spondylolisthesis. METHODS: In total, 468 cases of lumbar spondylolisthesis treated by decompression and fusion in our hospital from January 2017 to January 2020 were included in this retrospective study. Among them, 238 cases were degenerative spondylolisthesis (group A), and 230 cases were isthmic spondylolisthesis (group B). Sex, age, body mass index, bone mineral density, preoperative visual analog scale (VAS) and Oswestry Disability Index (ODI) scores, postoperative VAS and ODI scores at 1 month and 3 months, and angle of the proximal facet joint at the last follow-up were recorded and compared between the two groups. The degree of pedicle screw invasion of the proximal facet joint was graded and compared by the SEO grading method. RESULTS: There were no significant differences in sex, age, body mass index, bone mineral density, preoperative VAS and ODI scores, or proximal facet joint angle between the two groups (P > 0.05). There was no significant difference in VAS and ODI scores between the two groups at 1 month and 3 months after the operation (P > 0.05). The VAS score of group A at the last follow-up was 1 (1,2). The VAS score of group B at the last follow-up was 3 (1,3). The ODI score of group A at the last follow-up was 6(4,26). The ODI score of group B at the last follow-up was 15(8,36). The VAS and ODI scores of the two groups at the last follow-up were significantly different (P < 0.05). According to the SEO grading method, the invasion of the proximal articular process by pedicle screw placement in group A involved 320 cases in grade 0, 128 cases in grade I and 28 cases in grade II. In group B, there were 116 cases in grade 0, 248 cases in grade I and 96 cases in grade II, with a significant difference (P < 0.01). CONCLUSION: In summary, a certain number of cases involving screws invading the proximal facet joint occurred in the two different types of lumbar spondylolisthesis, but the number in the isthmic spondylolisthesis group was significantly higher than that in the degenerative spondylolisthesis group, which caused more trauma to the proximal facet joint and significantly affected the patient prognosis.

Multivariate analysis of pedicle screw invasion of the proximal facet joint after lumbar surgery.

BACKGROUND: To analyze the risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery. METHODS: From January 2019 to January 2021, 1794 patients with lumbar degenerative disease, such as lumbar disc herniation, lumbar spinal stenosis and lumbar spondylolisthesis, were treated at our hospital. In all, 1221 cases were included. General data (sex, age, BMI), bone mineral density, proximal facet joint angle, degenerative lumbar spondylolisthesis, isthmic lumbar spondylolisthesis and fixed segment in the two groups were recorded. After the operation, vertebral CT of the corresponding surgical segments was performed for three-dimensional reconstruction and evaluation of whether the vertebral arch root screw interfered with the proximal facet joint. The included cases were divided into an invasion group and a noninvasion group. Univariate analysis was used to screen the risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery, and the selected risk factors were included in the logistic model for multivariate analysis. RESULTS: The single-factor analysis showed a significant difference in age, BMI, proximal facet joint angle, degenerative lumbar spondylolisthesis, and fixed segment (P < 0.1). Multifactor analysis of the logistic model showed a significant difference for age ≥ 50 years (P < 0.001, OR = 2.291), BMI > 28 kg/m2 (P < 0.001, OR = 2.548), degenerative lumbar spondylolisthesis (P < 0.001, OR = 2.187), gorge cleft lumbar relaxation (P < 0.001, OR = 2.410), proximal facet joint angle (35 ~ 45°: P < 0.001, OR = 3.151; > 45°: P < 0.001, OR = 3.578), and fixed segment (lower lumbar spine: P < 0.001, OR = 2.912). CONCLUSION: Age (≥ 50 years old), BMI (> 28 kg/m2), proximal facet joint angle (35 ~ 45°, > 45°), degenerative lumbar spondylolisthesis, isthmic lumbar spondylolisthesis and fixed segment (lower lumbar spine) are independent risk factors for pedicle screw invasion of the proximal facet joint after lumbar surgery. Compared with degenerative lumbar spondylolisthesis, facet joint intrusion is more likely in isthmic lumbar spondylolisthesis.

Analysis and comparison of a spinal cord injury model with a single-axle-lever clip or a parallel-moving clip compression in rats.

STUDY DESIGN: Experimental animal study. OBJECTIVES: To assess the feasibility of a custom-designed parallel-moving (PM) clip, compared with a single-axle-lever (SAL) clip, for the development of a compressional spinal cord injury (SCI) model in rats. SETTING: Hospital laboratory in China. METHODS: We used a PM clip and a SAL clip with same compression rate, to develop a SCI model in rats, and set a sham group as a blank control. Within 3 weeks, each group of rats was evaluated for behavioral (Basso-Beattie-Bresnahan locomotor rating score, BBB), and electrophysiological changes (somatosensory evoked potential), and historical staining to observe the differences between the three groups. In particular, the mechanical results of the PM group were calculated. RESULTS: The BBB scores for the SAL and PM groups were significantly lower than those for the sham group (P < 0.05), no significant difference between the two methods (P > 0.05), but the values corresponding to the PM group had smaller standard deviations. The interpeak-latency (IPL) was significantly prolonged (P < 0.0001) and the peak-peak amplitude (PPA) was significantly reduced (P < 0.01) in SAL and PM groups than those in the sham group, but there was no statistical difference in both IPL and PPA between the two SCI groups (P > 0.05). Histological staining showed obvious pathological changes in two SCI groups, and the shape of the lesion zone in the PM group was more symmetrical than that in the SAL groups. CONCLUSIONS: The use of a compressional SCI model in rats with the PM clip we designed is an appropriate method to quantify the injury. The degree of the injury caused by this clip is more stable and uniform than those with classical methods.

Relationship between degenerative scoliosis and lower extremity mechanical parameters based on EOS imaging system.

OBJECTIVE: This study aimed to assess the correlation between coronal imbalance and lower-limb physiological parameters in degenerative scoliosis using the biplanar whole body imaging system (EOS). MATERIALS AND METHODS: A total of 101 successive EOS images were selected between January 2018 and December 2021. Of the selected images, 63 patients were in the degenerative scoliosis group (DSG) and 38 patients were in the control group (CG). Two independent observers performed measurements of the parameters and compared the two groups. RESULTS: Among parameters examined, significant inter-group differences were found for coronal pelvic tilt angle (CPT), bilateral femoral length difference (ΔFL), and bilateral total lower limb length (ΔTL) difference. Additionally, the knee and ankle joints had more severe degeneration on the main curved side in patients with degenerative scoliosis. In the left curved group, 18 (42.86%) and 24 (57.1%) patients had more severe degeneration in the left knee and left ankle, respectively. In the right lateral bending group, 13 (61.9%) and 14 (66.7%) patients had more severe degeneration in the right knee and right ankle, respectively. Statistical differences were found in the degree of degeneration in both knee and ankle joints bilaterally. CONCLUSION: This study showed that biomechanical parameters of the lower limbs are affected in cases of degenerative scoliosis with altered coronal balance. The lower limb on the main curve side became shorter compared to its counterpart, and joint degeneration of the knee and ankle joints became more severe.