BACKGROUND:Osteoporosis is defined as a chronic metabolic bone disease,and a large amount of evidence has shown that gut microbiota is involved in osteoporosis.However,the causal relationship between gut microbiota and osteoporosis is yet unclear.OBJECTIVE:To evaluate the potential causal relationship between gut microbiota and osteoporosis using the two-sample Mendelian randomization.METHODS:Pooled statistics from the MiBioGen Consortium's Genome-Wide Association Analysis(GWAS)of gut microbiota and GWAS data from the UK Biometric Sample database for osteoporosis were used.Inverse variance weighting(IVW),MR-Egger regression,weighted median,weighted model and simple model were used to study the causal relationship between gut microbiota and osteoporosis.Sensitivity analysis was used to test whether the results of Mendelian randomization are reliable.RESULTS AND CONCLUSION:The inverse variance weighted method showed that there was a causal relationship between gut microbiota and osteoporosis.Among them,the R7 genus of Christensenaceae(MR Egger:β=-0.007;IVW:β=-0.004,P=0.028),Coprococus 3(MR Egger:β=-0.008;IVW:β=-0.003,P=0.046)and Trichospirillum(MR Egger:β=-0.009;IVW:β=-0.004,P=0.003)may be protective factors for osteoporosis,while Hotella(MR Egger:β=0.006;IVW:β=0.002,P=0.033)and Eubacterium oxyoxide(MR Egger:β=0.001;IVW:β=0.003,P=0.046)may be potential risk factors for osteoporosis.Eubacterium oxyoxide and Hotella can increase the risk of osteoporosis,while R7 of Christensenaceae,Coprococcus 3 and Spirillum can reduce the risk of osteoporosis.Whether this conclusion also applies to non-European populations will need to be verified in the future by large clinical trials in different groups.

BACKGROUND:Osteoporosis is defined as a chronic metabolic bone disease,and a large amount of evidence has shown that gut microbiota is involved in osteoporosis.However,the causal relationship between gut microbiota and osteoporosis is yet unclear.OBJECTIVE:To evaluate the potential causal relationship between gut microbiota and osteoporosis using the two-sample Mendelian randomization.METHODS:Pooled statistics from the MiBioGen Consortium's Genome-Wide Association Analysis(GWAS)of gut microbiota and GWAS data from the UK Biometric Sample database for osteoporosis were used.Inverse variance weighting(IVW),MR-Egger regression,weighted median,weighted model and simple model were used to study the causal relationship between gut microbiota and osteoporosis.Sensitivity analysis was used to test whether the results of Mendelian randomization are reliable.RESULTS AND CONCLUSION:The inverse variance weighted method showed that there was a causal relationship between gut microbiota and osteoporosis.Among them,the R7 genus of Christensenaceae(MR Egger:β=-0.007;IVW:β=-0.004,P=0.028),Coprococus 3(MR Egger:β=-0.008;IVW:β=-0.003,P=0.046)and Trichospirillum(MR Egger:β=-0.009;IVW:β=-0.004,P=0.003)may be protective factors for osteoporosis,while Hotella(MR Egger:β=0.006;IVW:β=0.002,P=0.033)and Eubacterium oxyoxide(MR Egger:β=0.001;IVW:β=0.003,P=0.046)may be potential risk factors for osteoporosis.Eubacterium oxyoxide and Hotella can increase the risk of osteoporosis,while R7 of Christensenaceae,Coprococcus 3 and Spirillum can reduce the risk of osteoporosis.Whether this conclusion also applies to non-European populations will need to be verified in the future by large clinical trials in different groups.

Objective:To investigate the clinical significance of a new classification system for atlas fractures based on pre- and post-treatment CT features, with a focus on diagnosis and treatment.Methods:A retrospective analysis was conducted on 75 cases of cervical vertebra fractures treated at the Sixth Hospital of Ningbo City between January 2015 and December 2020. The study included 44 males and 31 females, with an average age of 53.3±13.0 years (range: 27-81 years). The fractures were classified according to the Landells classification, resulting in 12 cases of type I, 13 cases of type II, 33 cases of type III, 9 cases that were difficult to classify due to fracture lines located at anatomical junctions, and 8 cases that could not be classified using the Landells classification due to diverse injury mechanisms. To establish a new preliminary classification for cervical vertebra fractures, the researchers considered whether the fracture line in the CT images involved the facet joint surface of the atlas, the impact on bilateral half-rings, and the displacement distance of the fracture ends. Five spinal surgeons were randomly selected to classify the CT images of the 75 patients using the new classification method. After one month, the imaging data of the 75 cases of cervical vertebra fractures were randomized and reclassified to assess the reliability and repeatability of the classification.Results:The new cervical vertebra fracture classification method comprised three types based on whether the fracture line involved the facet joint surface of the atlas: type A (no involvement of the facet joint surface of the atlas), type B (involvement of one side of the facet joint surface with intact contralateral half-ring), and type C (involvement of one side of the facet joint surface with fractured contralateral half-ring). Additionally, based on the maximum displacement distance between the fracture ends (>4 mm), six subtypes were identified: subtype 1 (≤4 mm displacement) and subtype 2 (>4 mm displacement). Consequently, the subtypes were classified as A1, A2, B1, B2, C1, and C2. According to the new classification method, the 75 patients included 17 cases of A1, 12 cases of A2, 7 cases of B1, 13 cases of B2, 12 cases of C1, and 14 cases of C2. The classification demonstrated excellent consistency, as assessed by the five doctors, with Kappa values of 0.85 and 0.91 for reliability and repeatability, respectively. At the final follow-up, all conservatively treated patients achieved bone healing, while four surgically treated patients experienced non-union of the fracture ends but exhibited good fusion between the atlas and axis. The remaining surgically treated patients achieved bony union without complications such as loosening or fracture of internal fixation.Conclusion:The new cervical vertebra fracture classification method, based on CT imaging features, comprehensively covers common clinical cases of cervical vertebra fractures and demonstrates excellent consistency. It provides valuable clinical guidance for the diagnosis and treatment of cervical vertebra fractures.

Objective:To study the early predictive value of urine neutrophil gelatinase-associated lipoprotein (NGAL) and kidney injury molecule-1 (KIM-1) for acute kidney injury (AKI) in neonates with severe asphyxia.Method:From January 2019 to June 2020, neonates with severe asphyxia admitted to our hospital within 6 hours after birth were enrolled in the study. The dynamic changes of urine NGAL and KIM-1 at admission, 24 h, 48 h and 1 w after birth were examined. Neonates were assigned into AKI group and non-AKI group according to the clinical practice guidelines for AKI issued by KDIGO (Kidney Disease: Improving Global Outcome). The sensitivity and specificity of NGAL and KIM-1 predicting AKI at different time points were evaluated using ROC curve and area under curve (AUC).Result:According to the diagnostic criteria of neonatal AKI, 9 cases were in the AKI group and 42 cases in the non-AKI group, and the incidence of AKI was 17.6%. Urine NGAL was significantly increased in AKI group at admission and 24 h after birth compared with the non-AKI group [(115.6±75.5) ng/ml vs. (49.8±29.0) ng/ml, (90.7±35.6) ng/ml vs. (55.6±30.7) ng/ml] ( P<0.05). No significant differences existed at 48 h and 1 w after birth between the two groups. At 24 h after birth, urine KIM-1 in the AKI group was significantly higher than the non-AKI group [(808.3±555.3) pg/ml vs. (318.4±234.0) pg/ml, P<0.05] and no significant differences existed between the two groups at admission, 48 h and 1 w after birth. The AUC of NGAL predicting AKI at admission, 24 h, 48 h and 1w after birth were 0.804 (95% CI 0.573~1.000), 0.792 (95% CI 0.580~1.000), 0.732 (95% CI 0.517~0.947) and 0.551(95% CI 0.371~0.730), respectively. The AUC of KIM-1 predicted AKI at admission, 24 h, 48 h and 1 w after birth was 0.860 (95% CI 0.676~1.000), 0.824 (95% CI 0.655~0.993), 0.768 (95% CI 0.622~0.914), 0.622 (95% CI 0.392~0.852), respectively. Conclusion:At admission, 24 h and 48 h after birth, urine NGAL and KIM-1, as kidney injury markers, may predict the occurrence of AKI after severe neonatal asphyxia.

Objective:To explore the difference in properties of anterior occipital condyle plate screws compared with common anterior occipitalcervical fusion internal fixation.Methods:A 28-year-old healthy adult male volunteer's CT data of the occiput and neck was selected to establish finite element models：including the normal model，simple artificial vertebral fixation model（special-shaped titanium cage+clival screws），anterior occipital condyle plate and screw fixation model，and clival plate and screw fixation model，then a 50 N gravity and a torque of 1.5 N m were exerted upon the upper surface of the occipital bone to make the model produce flexion and extension，lateral bending and rotation. The motion range，internal fixation stress distribution and occipital bone stress distribution of each model under varying conditions were compared.Results:Under the conditions of flexion，extension，lateral bending and rotation，the range of motion of the normal model was 18.65°，15.35°，9.82° and 34.68°，respectively；that of the simple artificial vertebral fixation model was 3.20°，3.63°，2.94° and 3.92°，respectively；that of the clival plate and screw fixation model was 0.40°，0.50°，0.35° and 0.89°，respectively；that of the anterior occipital condylar plate and screw fixation model was 0.27°，0.33°，0.13° and 0.30°，respectively. Compared with the simple artificial vertebral fixation model，the range of motion of the clival plate and screw fixation model decreased by 87.5%，86.2%，88.1% and 77.3% in flexion，extension，lateral bending and rotation. The range of motion of the anterior occipital condylar plate and screw fixation model decreased by 91.5%，90.1%，95.6% and 92.3%，respectively. Under the conditions of flexion and extension，lateral bending and rotation，the stress peak of the simple artificial vertebral fixation model was 52.3 MPa，51.9 MPa，52.6 MPa，respectively；that of the clival plate and screw fixation was 100.1 MPa，158.1 MPa，170.6 MPa，respectively；that of the anterior occipital condylar plate and screw fixation was 114.2 MPa，62.9 MPa，132.9 MPa，respectively. Under the condition of flexion and extension，lateral bending and rotation，the stress peak of the occipital bone in the simple artificial vertebral body internal fixation model was 52.9 MPa，50.9 MPa and 62.3 MPa，respectively；that of the clival plate and screw fixation model was 19.7 MPa，55.9 MPa and 38.3 MPa，respectively；that of the anterior occipital condylar plate and screw fixation model was 37.8 MPa，15.0 MPa and 16.3 MPa，respectively. The stress in bone near the hypoglossal canal was close to 0 MPa，much smaller than the stress peak in occipital bone.Conclusion:Anterior occipital condylar plate and screw fixation in front of the special-shaped titanium cage can improve the stability of occipitocervical fusion with little effect on the occipital bone and hypoglossal canal or without obvious stress concentration，and hence is a safe and reliable anterior fixation method for upper cervical spine instability.

Objective:To investigate the safety of posterior atlantoaxial transarticular screw combined with atlas pedicle screw fixation in Chinese.Methods:CT data of upper cervical spine in 48 patients were collected from Ningbo No.6 Hospital, including 26 males and 22 females aged 26-58 years [(37.3±13.5)years]. All CT data was transformed into 3D dimensional model and inserted with virtual screws by Mimics 19.0. Firstly, the vertical plane P 1 and the horizontal plane P 2 of the atlas were built in those atlantoaxial models, secondly the atlantoaxial transarticular screw S 0 was inserted by Margel method, and it's insertion point was located at 3 mm lateral and 2 mm cephalad in the C 2 inferior articular process. Finally, four atlas pedicle screws were inserted at the midline of atlas lateral mass. The four screws are inserted as follows. S 1: the screw was tangent to the lateral side of the S 0 or the medial of the atlas pedicle. S 2: the screw was tangent to the lateral wall of the atlas pedicle. S 3: the screw was tangent to the upper wall of the atlas pedicle. S 4: the screw was tangent to the inferior wall of the atlas pedicle. The angles between S 1, S 2 and P 1 as the camber angle, and the angle between S 3, S 4 and P 2 as the gantry angle were measured. Then the safety range of camber angle and gantry angle were calculated, and the screw length of S 1, S 2, S 3 and S 4 was measured. In all models, the camber angle and gantry angle of the screws were adjusted an interval of 2°, the number of successful cases was calculated and the success rate of insertion was calculated. Results:All 3D models were inserted successfully. The minimum value, maximum value and safety range of the camber angle of atlas pedicle screws were (-6.7±5.2)°, (10.4± 4.3)°, (17.1±3.7)°, respectively; and of the gantry angle were (-0.5±3.5)°, (11.0±5.8)°, (11.5±4.9)°, respectively. The length of screw placement was S 1: (31.1±2.4)mm, S 2: (28.3±2.5)mm, S 3: (29.2±3.8)mm, S 4: (29.6±3.0)mm, respectively ( P<0.05). When the camber angle was from -1°to 5°, the success rate of screw placement was 87.5%; when inserting with 2° camber angle, the success rate was 100%; when the gantry angle was 5°, the success rate was 93.8%. Conclusion:The posterior atlantoaxial transarticular screw combined with atlas pedicle screw can achieve satisfy insertion length and success rate.

Objective:To investigate the efficacy of screw-rod fixation and fusion in revision surgery after percutaneous vertebroplasty (PVP) or percutaneous kyphoplasty(PKP) for osteoporotic vertebral fractures (OVFs).Methods:A retrospective case series study was carried out on clinical data of 19 patients treated by revision surgery after PVP or PKP at Zhejiang Ningbo No.6 Hospital from January 2014 to December 2017. There were 5 males and 14 females, with age of (70.7±6.0)years (range, 58-81 years). Injured segment was located at T 9 in 1 patient, T 11 in 3, T 12 in 5, L 1 fracture in 5, L 2 in 2, L 3 in 2 and L 4 in 1. Caused for revision and operation methods were as follows, 5 patients underwent debridement, screw-rod fixation and fusion due to infection, 9 patients underwent osteotomy due to progressive kyphosis, screw-rod fixation and fusion, 5 patients underwent spinal canal decompression, screw-rod fixation and fusion due to neurological dysfunction. The operation time, intraoperative blood loss, and perioperative complications were recorded. The white blood cell (WBC), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were used to evaluate the control of infection before operation, before discharge and at postoperative 3 months. The changes in Cobb angle were measured before and after operation and at the final follow-up. The American spinal injury association (ASIA) scale, visual analog scale (VAS) and Oswestry disability index (ODI) were evaluated at the final follow-up. Results:All patients were followed up for 24-46 months [(32.7±8.3)months]. The revision operation time was 135-320 minutes [(226.3±75.6)minutes]. The intraoperative blood loss was 350-1 500 ml [(825.5±230.6)ml]. There were 1 patient with poor wound healing, 2 with pulmonary infection, and 2 with hardware loosening. The WBC, ESR and CRP decreased from preoperative (9.2±1.7)×10 9/L, (88.7±19.2)mm/h, (58.7±22.9)mg/L to (7.3±0.9)×10 9/L, (42.5±13.7)mm/h, (37.3±16.3)mg/L before discharge, and (6.6±0.7)×10 9/L, (26.8±9.5)mm/h, (17.8±8.6)mg/L at postoperative 3 months ( P<0.01). The Cobb angle improved from preoperative (29.3±5.2)° to (4.8±1.2)° ofter operation and (7.3±1.6)° at the final follow-up ( P<0.05). The patients with ASIA grade C ( n=2) and grade D ( n=1) improved to grade E, and the patients with ASIA grade C ( n=2) improved to grade D at the final follow-up. Imagines showed good bone fusion in all patients at the last follow-up. The mean VAS decreased from preoperative (7.5±0.8)points to (2.1±0.5)points at the last follow-up ( P<0.05). The ODI decreased from preoperative (60.7±15.2)% to (19.9±5.9)% at the last follow-up ( P<0.05). Conclusion:For patients with OVFs undergoing revision surgery after PVP or PKP, debridement, kyphosis correction, spinal canal decompression combined with screw-rod fixation and fusion can reduce infection, correct kyphotic deformity, improve neurological function, relieve pain and improve quality of life.

Objective: To compare the clinical efficacy of posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or iliac bone graft for atlantoaxial instability. Methods: A retrospective case-control study was conducted to analyze the clinical data of 56 patients with atlantoaxial instability admitted to the Sixth Hospital of Ningbo from September 2014 to October 2016. There were 35 males and 21 females, with the age range from 9 to 59 years [(50.3±3.2)years]. A total of 26 patients were treated with posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft (complex group), while 30 patients were treated with iliac bone graft (ilium group). Patients showed different degrees of neck pain and limited neck activity preoperatively. X-ray films and three-dimensional CT examination of the cervical spine were taken before and after operation for evaluating the atlantoaxial reduction, bone graft fusion and internal fixation. The operation time, intraoperative bleeding, bone fusion time, visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) score, atlantodental interval (ADI) and axial symptoms were compared between the two groups, and the complications were recorded. Results: Both groups were followed up for 24-30 months, with an average of 27.4 months. In the complex group and the ilium group, the operation time was (2.21±0.25)hours and (2.72±0.26)hours (P<0.01); the intraoperative blood loss was (227.3±45.4)ml and (277.7±43.4)ml, respectively (P<0.05); the bone fusion time was (6.9±0.5)months and (8.1±1.8)months (P>0.05), respectively. In the complex group, the VAS was (5.45±0.69)points before operation, (2.64±0.51)points at the follow-up one month after operation, (0.91±0.7)points at the follow-up 12 months after operation, and (0.45±0.16)points at the follow-up 24 months after operation; and in the ilium group, the VAS was (5.18±0.75)points, (2.45±0.52)points, (1.27±0.19)points and (0.41±0.18)points correspondingly. In terms of VAS, there were significant differences before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). In the complex group, the JOA score was (10.82±0.35)points before operation, (12.73±0.65)points at the follow-up one month after operation, (15.18±0.61)points at the follow-up 12 months after operation, and (15.64±0.15)points at the follow-up 24 months after operation; and in the ilium group, the JOA score was (10.73±1.19)points, (13.01±0.63)points, (14.73±0.91)points and (15.55±0.51)points correspondingly. In terms of JOA score, there were significant differences between before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). In the complex group, the ADI was (2.28±0.59)mm before operation, (1.83±0.56)mm at the follow-up one month after operation, (1.71±0.56)mm at the follow-up 12 months after operation, and (1.59±0.67)mm at the follow-up 24 months after operation; and in the ilium group, the ADI was (2.23±0.60)mm, (1.80±0.18)mm, (1.67±0.69)mm and (1.62±0.53)mm correspondingly. In terms of ADI, there were significant differences between before and after operation within each group (P<0.01), while there were no significant differences between the two groups at different time points (P>0.05). The axial symptom scores were graded as excellent in 23 patients and good in three patients of the complex group while excellent in 21 patients and good in nine patients in the ilium group (P>0.05). There were no patients with spinal nerve injury caused by pedicle screw placement after operation. One patient in the ilium group had incision errhysis and recovered after dressing change, and other patients had no incision infection. Conclusions For atlantoaxial instability, posterior atlantoaxial screw-rod fixation combined with spinous process muscle-vessel complex bone graft or autogenous iliac bone graft can both achieve satisfactory clinical results. The spinous process-muscle-vascellum complex graft has less operation time and intraoperative bleeding than the autogenous iliac bone graft, which can be a feasible alternative operation.

Objective: To investigate the accuracy and feasibility of individual 3D printing model for pedicle screw placement in treating patients with upper cervical spine fracture. Methods: A retrospective case control study was conducted to analyze the clinical data of 30 patients with upper cervical spine fracture admitted to Ningbo No.6 Hospital from August 2013 to December 2018. There were 19 males and 11 females, aged 45-67 years with an average age of 53.5 years. The 15 patients in the study group were treated with pedicle screw fixation and another 15 patients in the control group were treated with traditional freehand screw fixation. A total of 120 pedicle screws were implanted, with 60 screws in each group. The operation time, intraoperative blood loss, preoperative and postoperative visual analogue score (VAS), Japan Orthopedic Association (JOA) score were recorded. The position and grade of screws were evaluated according to Kawaguchi's evaluation method of screw grade after operation. The patients took monthly reexamination for the first three months after discharge. In the first two months after discharge, the patients took X-ray examination for observation of screw loosening or rupture of internal fixation. At the third month after operation, the patients took CT of cervical spine for observation of bone healing and fusion. Results: The mean follow-up duration was 17.8 months (range, 13-21 months). The study group had shorter operation time (99.13±3.04)minutes compared with the control group (107.00±6.92) minutes (P<0.01). There were no significant differences in intraoperative blood loss, preoperative VAS, JOA scores before operation and 1 year after operation between the two groups (P>0.05), but the VAS in study group was significantly lower than that in control group (P<0.05). In the study group, the VAS score 1 year after operation [(2.3±0.5)points] was lower than that before the operation [(7.7±0.7)points], and the JOA score [(16.8±0.4)points] was significantly higher than that before the operation [(15.9±0.7)points](P<0.01). In the control group, the VAS 1 year after operation [(2.5±0.5)points] was significantly lower than that before operation [(7.5±0.5)points] (P<0.01), and the JOA score [(16.5±0.5)points] was significantly higher than that before operation [(15.9±0.8)points] (P<0.05). In the study group, according to the CT results, there were 28 atlas pedicle screws of grade 0 (93.3%), two of grade 1 (6.7%), 0 of grade 2, 0 of grade 3, and there were 27 axial pedicle screws of grade 0 (90.0%), three of grade 1 (10.0%), 0 of grade 2, and 0 of grade 3. In the control group, there were 25 atlas pedicle screws of grade 0 (83.3%), four of grade 1 (13.3%), one of grade 2 (3.4%), 0 of grade 3, and there were 27 axial pedical screws of grade 0 (90.0%), three of grade 1 (10.0%), 0 of grade 2, and 0 of grade 3. There was no significant difference in the accuracy of pedicle screw placement between the two groups (P>0.05). No serious complications such as spinal cord or vertebral artery injury occurred. At 3 months after operation, CT showed that the fracture of cervical vertebra healed. Conclusion Individualized 3D printed cervical spine model can guide the pedicle screw placement for upper cervical spine fracture, which can shorten the operation time, reduce the postoperative pain of patients, improve the accuracy of screw placement, and reduce the risks related to operation.

Objective: To investigate the efficacy of microscope-assisted free-hand atlantal pedicle screw technique for unstable atlas burst fracture. Methods: A retrospective case control study was conducted to analyze the clinical data of 48 patients with unstable atlas burst fracture admitted to Ningbo No.6 hospital from January 2016 to June 2018. There were 32 males and 16 females, aged 24-72 years [(49.5±15.2 years)]. A total of 22 patients were treated with the technique of atlas screw placement by drill under microscope (Group A), including 14 males and eight females, aged 24-68 years. Twenty six patients (Group B) were treated with atlantal pedicle screw placement by hand, including 18 males and 8 females, aged 26-72 years [(50.7±15.4 years)]. The operation time, intraoperative blood loss and the times of intraoperative fluoroscopy were compared between the two groups. X-ray and CT were reexamined to evaluate the accuracy of screw placement within one week after operation. The visual analogue score (VAS) and cervical dysfunction index (NDI) were compared before operation and 1 year after operation. The intraoperative complications were recorded. One year after operation, X-ray and CT were reexamined to observe fracture healing, atlantoaxial fusion and failure of internal fixation. Results: Group A was followed up for 12-24 months [(18.4±6.8)months], and Group B for 12-24 months [(17.4±7.2)months]. The amount of intraoperative bleeding [(180.5±60.8) ml] and the times of intraoperative fluoroscopy [(1.3±0.8) times] in Group A were significantly lower than those in Group B [(280.1±80.2) ml, (2.2±0.8) times] (P<0.05), but there was no significant difference in the time of operation and the accuracy of screw placement (P>0.05). There were statistically significant differences in VAS and NDI before operation and one year after operation in both groups (P<0.05), but there was no significant difference between the two groups (P>0.05). No serious complications such as vertebral artery, nerve root and spinal cord injury occurred. One year follow-up CT showed healed fracture or continuous bone bridge passing through the atlantoaxial intervertebral space. Except for one patient in Group B with lost reduction, other patients had no loosening or fracture of internal fixation. Conclusion Compared with screw placement by hand, the pedicle screw placement by drill under the microscope can reduce the amount of bleeding and the times of fluoroscopy.