This study aims to establish a high-performance size-exclusion chromatography (HPSEC) method for determining the content of the classical swine fever virus (CSFV) E2 protein and screen the optimal stabilizer to enhance the stability of this protein. The optimal detection conditions were determined by optimizing the composition of the mobile phase, and characteristic chromatographic peaks were identified by SDS-PAGE and Western blotting. The specificity, repeatability, precision, linearity, limit of detection (LOD), and limit of quantitation (LOQ) of the method were assessed. The method established was used to determine the content of CSFV E2 protein antigen and vaccine. Differential scanning fluorimetry (DSF) was employed to screen the buffer system, pH, and salt ion concentrations, and sugar, amino acid, and alcohol stabilizers were further screened. The results showed that using a 200 mmol/L phosphate buffer provided the best column efficiency. An antigen-specific chromatographic peak appeared at the retention time of 18 min, which was identified as the CSFV E2 protein by SDS-PAGE and Western blotting. The method exhibited high specificity for detecting the CSFV E2 protein, with no absorbance peak observed in the blank control. The relative standard deviation (RSD) of the peak area for six repeated injections of the CSFV E2 protein was 0.74%, indicating good repeatability of the method. The RSD for repeated detection of two different concentrations of CSFV E2 protein samples by different operators at different time points was less than 2%, suggesting good intermediate precision of the method. The peak area of the CSFV E2 protein was linearly related to its concentration, with the regression equation showing R² of 1.000. The LOD and LOQ of the method were 14.88 μg/mL and 29.75 μg/mL, respectively. Application of the developed method in the detection of three batches of CSFV E2 protein antigen and three batches of vaccine demonstrated results consistent with those from the bicinchoninic acid (BCA) assay, which meant that the method could accurately determine the content of CSFV E2 protein antigen and vaccine. The DSF method identified 50 mmol/L Tris-HCl at pH 8.0 as the optimal buffer, and the addition of sugar and alcohol stabilizers further improved the stability of the CSFV E2 protein. The HPSEC method established in this study is simple, fast, and exhibits good accuracy and repeatability, enabling precise measurement of the CSFV E2 protein content. It is expected to play a crucial role in the quality control of the CSFV E2 vaccine. Furthermore, the strategy for improving the CSFV E2 protein stability, identified through DSF screening, has significant implications for enhancing the stability of the CSFV E2 vaccine.
Classical Swine Fever Virus/chemistry* ; Chromatography, Gel/methods* ; Animals ; Swine ; Viral Envelope Proteins/immunology*

Objective:To explore the clinical characteristics and prognosis of primary renal dedifferentiated liposarcoma.Methods:A retrospective analysis was conducted on the clinical data of 10 patients diagnosed with renal dedifferentiated liposarcoma in the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2023. The cohort consisted of 8 males and 2 females, with a mean age of (59.0±6.8) years. Tumors were located in the left kidney in 8 cases and in the right kidney in 2 cases. Presentations included flank or abdominal masses in 4 patients, back pain in 3 patients, and asymptomatic in 3 patients. Imaging studies revealed solitary lesions in 9 cases and multiple lesions in 1 case. The maximum tumor diameter ranged from 95 to 178 mm, with a median of 119.5 mm. CT showed tumors within the renal parenchyma with unclear boundaries and displayed a "slow in, slow out" pattern of gradual enhancement. Clinical staging revealed T 2N 0M 0 in 3 cases, T 3N 0M 0 in 4 cases, T 4N 0M 0 in 3 cases, and T 2N 1M 0 in 1 case. Nine patients underwent radical nephrectomy, including 4 laparoscopic surgeries, 4 open surgeries, and 1 robotic-assisted with thrombectomy. One patient, presenting with multiple lymph node metastases confirmed by PET-CT, underwent a diagnostic biopsy. Postoperative pathological features, follow-up and prognosis were analyzed. Results:Pathological specimens appeared grayish-red, grayish-yellow or grayish-white cut surfaces with soft to moderate texture. Microscopically, tumor cells were ovoid or short spindle-shaped with significant atypia and cytoplasmic vacuoles, with visible pathological mitoses. Six cases showed only dedifferentiated components with tumor giant cells and multinucleated giant cells resembling pleomorphic undifferentiated sarcoma, with focal tumor necrosis. Fluorescence in situ hybridization showed MDM2 gene amplification in all cases. All cases were diagnosed as primary renal dedifferentiated liposarcoma. Pathological staging showed 4 cases as pT 2N 0M 0, 3 cases as pT 3N 0M 0, 2 cases as pT 4N 0M 0, and 1 case lacked pathological staging due to biopsy only. Five patients received postoperative adjuvant therapy, including two pT 2N 0M 0 cases who received immunotherapy and apatinib treatment respectively, with no recurrence. One pT 3N 0M 0 case received anlotinib treatment, with local recurrence after 12 months, followed by radiofrequency ablation combined with chemotherapy. Two pT 4N 0M 0 cases received ifosfamide combined with epirubicin and pirarubicin combined with lobaplatin respectively, with one case showing no progression at 11 months follow-up, and another case developing splenic metastasis 3 months post-surgery, followed by chemotherapy combined with targeted therapy, surviving for 20 months. Among the 4 cases without adjuvant therapy, two pT 2N 0M 0 cases developed multiple metastases within 1 month post-surgery and received immunotherapy combined with targeted therapy and/or chemotherapy, surviving 4-5 months.One of the two pT 3N 0M 0 cases developed local recurrence 2 months post-surgery and received chemotherapy, surviving 6 months, and another pT 3N 0M 0 case developed gluteal subcutaneous metastasis 1 month post-surgery and received immunotherapy combined with targeted therapy, surviving 8 months.One non-surgical pT 2N 1M 0 patient received chemotherapy and survived for 15 months. All patients were followed up for 4-52 months, with a median follow-up time of 11 months. At the last follow-up, 6 patients died and 4 survived. Conclusions:Primary renal dedifferentiated liposarcoma is clinically rare, with atypical symptoms and difficult preoperative diagnosis, relying on pathology for confirmation. Radical nephrectomy is the main treatment method, but surgery alone has poor prognosis with high recurrence and metastasis rates. Adjuvant therapy based on surgery may improve patient prognosis.Larger sample studies are needed for confirmation.

Objective:To explore the clinical characteristics and prognosis of primary renal dedifferentiated liposarcoma.Methods:A retrospective analysis was conducted on the clinical data of 10 patients diagnosed with renal dedifferentiated liposarcoma in the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2023. The cohort consisted of 8 males and 2 females, with a mean age of (59.0±6.8) years. Tumors were located in the left kidney in 8 cases and in the right kidney in 2 cases. Presentations included flank or abdominal masses in 4 patients, back pain in 3 patients, and asymptomatic in 3 patients. Imaging studies revealed solitary lesions in 9 cases and multiple lesions in 1 case. The maximum tumor diameter ranged from 95 to 178 mm, with a median of 119.5 mm. CT showed tumors within the renal parenchyma with unclear boundaries and displayed a "slow in, slow out" pattern of gradual enhancement. Clinical staging revealed T 2N 0M 0 in 3 cases, T 3N 0M 0 in 4 cases, T 4N 0M 0 in 3 cases, and T 2N 1M 0 in 1 case. Nine patients underwent radical nephrectomy, including 4 laparoscopic surgeries, 4 open surgeries, and 1 robotic-assisted with thrombectomy. One patient, presenting with multiple lymph node metastases confirmed by PET-CT, underwent a diagnostic biopsy. Postoperative pathological features, follow-up and prognosis were analyzed. Results:Pathological specimens appeared grayish-red, grayish-yellow or grayish-white cut surfaces with soft to moderate texture. Microscopically, tumor cells were ovoid or short spindle-shaped with significant atypia and cytoplasmic vacuoles, with visible pathological mitoses. Six cases showed only dedifferentiated components with tumor giant cells and multinucleated giant cells resembling pleomorphic undifferentiated sarcoma, with focal tumor necrosis. Fluorescence in situ hybridization showed MDM2 gene amplification in all cases. All cases were diagnosed as primary renal dedifferentiated liposarcoma. Pathological staging showed 4 cases as pT 2N 0M 0, 3 cases as pT 3N 0M 0, 2 cases as pT 4N 0M 0, and 1 case lacked pathological staging due to biopsy only. Five patients received postoperative adjuvant therapy, including two pT 2N 0M 0 cases who received immunotherapy and apatinib treatment respectively, with no recurrence. One pT 3N 0M 0 case received anlotinib treatment, with local recurrence after 12 months, followed by radiofrequency ablation combined with chemotherapy. Two pT 4N 0M 0 cases received ifosfamide combined with epirubicin and pirarubicin combined with lobaplatin respectively, with one case showing no progression at 11 months follow-up, and another case developing splenic metastasis 3 months post-surgery, followed by chemotherapy combined with targeted therapy, surviving for 20 months. Among the 4 cases without adjuvant therapy, two pT 2N 0M 0 cases developed multiple metastases within 1 month post-surgery and received immunotherapy combined with targeted therapy and/or chemotherapy, surviving 4-5 months.One of the two pT 3N 0M 0 cases developed local recurrence 2 months post-surgery and received chemotherapy, surviving 6 months, and another pT 3N 0M 0 case developed gluteal subcutaneous metastasis 1 month post-surgery and received immunotherapy combined with targeted therapy, surviving 8 months.One non-surgical pT 2N 1M 0 patient received chemotherapy and survived for 15 months. All patients were followed up for 4-52 months, with a median follow-up time of 11 months. At the last follow-up, 6 patients died and 4 survived. Conclusions:Primary renal dedifferentiated liposarcoma is clinically rare, with atypical symptoms and difficult preoperative diagnosis, relying on pathology for confirmation. Radical nephrectomy is the main treatment method, but surgery alone has poor prognosis with high recurrence and metastasis rates. Adjuvant therapy based on surgery may improve patient prognosis.Larger sample studies are needed for confirmation.

Hemangioma of the penile head is rare. This paper reported a patient, 16 years old, who was admitted to hospital due to the discovery of multiple masses on the head of the penis for more than two years. Physical examination showed that three vascular mass-like masses were distributed along the coronal sulcus at the 3, 9, and 12 points of the penile head, and the larger one was about 10 mm×5 mm size, blue-purple, soft, and painless. Ultrasound examination suggested that the patient had a penile head hemangioma. Surgical resection was performed, and the postoperative pathological diagnosis was penile head hemangioma.The follow-up of 3 months showed that the wound healed well without recurrence, and the penile head appearance was not obviously deform.

Objective:To explore the clinicopathological features and prognosis of renal mucinous tubular spindle cell carcinoma (MTSCC).Methods:The clinical data of 16 patients with MTSCC admitted to the First Affiliated Hospital of Zhengzhou University from July 2013 to July 2022 were retrospectively analyzed. There were six male cases and ten female cases. The mean age was (56.4±11.4) years old. Among them, 10 cases were asymptomatic, two complained of hematuria, three complained of lumbar pain, and one complained of lower limb pain. Twelve cases underwent preoperative enhanced CT examination, 6 cases of ultrasound examination, 3 cases of MRI examination, and 1 case of bone scan. Imaging manifestations showed that the masses were round or round-like with clear borders. Two cases combined with hemorrhage and three cases combined with calcification. Five cases showed exophytic growth, 10 cases partially exophytic, and 1 case completely endophytic. The maximum diameter of the tumor was (65.7±27.4) mm. The tumors were located in the left kidney in 11 cases and in the right kidney in 5 cases. The tumors were mildly delayed-enhancing under enhanced CT, long/short T1 signal mixed with long/short T2 signal under MRI, and diffusion-limited high signal under DWI. The tumors were hypoechoic masses without obvious blood flow signals under ultrasound. Twelve cases were diagnosed as renal occupying neoplasms, 2 cases were suggested as lack of blood supply renal tumor, and one was considered renal tumor rupture and bleeding. In one case, a bone scan suggested metastasis to the thoracic spine and pelvis. The metastatic renal tumor was diagnosed, and a renal puncture was performed to clarify the pathology. Eleven patients underwent laparoscopic radical nephrectomy, and 4 patients underwent partial nephrectomy. One case was metastasized without surgery and treated with apatinib mesylate and zoledronic acid.Results:The postoperative pathological specimens showed grayish, grayish-yellow, or grayish-red masses with a soft or medium texture. No perinephric, ureteral, or adrenal invasion was seen in all tumors. Microscopically, the tumor cells were round and ovoid. The tumor cells were arranged in tubular and striated shapes, and mucus pools were locally visible. No sarcomatous component was seen in all tumors. There were 9 patients with pT 1N 0M 0, 6 patients with pT 2N 0M 0, and 1 patient with pT 1N 0M 1. After operation, 2 patients with pT 2N 0M 0, who underwent laparoscopic radical nephrectomy were treated with pazopanib and sunitinib, respectively. All patients were followed up for a median of 50.7(25.8, 75.0)months, 15 patients were free of recurrent metastases, and 1 patient with pre-puncture metastasis died due to tumor progression of multiple pulmonary and bone metastases, with a survival of 16.9 months. Conclusions:Renal MTSCC is rare, mostly found on physical examination, with female patients predominantly, and imaging shows a lack of blood supply tumor. Surgery is the primary treatment method. Partial nephrectomy or radical nephrectomy could be chosen according to the tumor stage, kidney function, and patient's underlying condition, and patients have a good prognosis.

Objective:To investigate the current status of hospitalized neonatal death of different gestational ages in Shaanxi Province.Methods:All neonatal deaths in six hospitals in Shaanxi Province from 2016 to 2020 were retrospectively analyzed, and the differences in perinatal complications, the causes of death, and the age at death were compared using Chi-square (or Fisher's exact ) test. Results:(1) Totally, 220 488 neonates were delivered in the obstetric department of the six hospitals during the study period; 71 782 out of them were admitted to the neonatal department. While 424 neonatal death was reported, giving the total hospitalized neonates mortality rate of 5.5‰ (394/71 782), which included 152 deaths of transferred patients ( n=9 103, 16.7‰), 226 premature (53.3%), 196 term (46.2%), and two post-term infants (0.5%). (2) Among mothers of dead neonates, 73.6% were found to have at least one perinatal complication. The most common one was fetal distress (146 cases, 34.4%), followed by gestational diabetes mellitus (113 cases, 26.7%), amniotic fluid abnormalities ( n=73, 17.2%), maternal infectious diseases ( n=71, 16.8%), and hypertensive disorders in pregnancy (HDP) ( n=52, 12.3%). The lower the gestational age, the higher the proportion of multiple pregnancies and assisted reproduction technology applied (Fisher exact test, P<0.05). On the contrary, the higher the gestational age, the higher the cesarean section rate ( χ 2=26.69, P<0.001). HDP was more likely to occur in the gestational age of 28-31 +6 and 32-34 +6 weeks ( χ 2=37.16, P<0.001), and amniotic fluid abnormalities were more likely to occur in those over 37 weeks ( χ 2=27.47, P<0.001). (3) The five leading causes of neonatal death were neonatal respiratory distress syndrome (NRDS, n=100, 23.6%), neonatal asphyxia ( n=88, 20.8%), maternal infectious diseases ( n=80, 18.9%), and birth defects ( n=54, 12.7%), and pulmonary hemorrhage ( n=22, 5.2%). The first three causes of death in term and post-term infants were neonatal asphyxia ( n=65, 32.8%), birth defects ( n=42, 21.2%), and infectious diseases ( n=26, 13.1%). NRDS ( n=83, 36.7%), infectious diseases ( n=54, 23.9%), and neonatal asphyxia ( n=23, 10.2%) were the three leading causes of death of premature babies. (4) Out of the 326 (76.9%) neonatal deaths within seven days after birth, 162 (38.2%) died within 24 h after birth and 164 cases (38.7%) between one to seven days after birth. Conclusions:Most neonatal deaths occurred among preterm ones and within seven days after birth, whose mothers suffered perinatal complications. The causes of neonatal death vary among different gestational age groups.

Objective:To compare the efficacy and safety of programmed death-1(PD-1)inhibitors in combination with chemotherapy versus chemotherapy alone in patients with metastatic bladder cancer.Methods:A retrospective analysis was performed on the clinical data of 77 cases of metastatic bladder cancer who were admitted to the First Affiliated Hospital of Zhengzhou University from January 2014 to October 2022. According to the different clinical treatment regimens, they were divided into two groups. Patients treated with PD-1 inhibitors combined with gemcitabine and cisplatin (GC) regimen were referred to as IGC group, and patients who received GC chemotherapy alone were referred to as GC group. There were 24 cases in IGC group, including 18 males and 6 females, with a median age of 60 (56, 67) years old. Seventeen cases had a history of smoking. Fifteen cases had an Eastern Cooperative Oncology Group (ECOG) score of 0 and 9 cases had a score of 1. Twenty-three cases suffered distant metastasis (stage M 1). Two cases suffered lymph node metastasis only, 6 cases with liver metastasis, 8 cases with lung metastasis, and 8 cases with bone metastasis. There were 53 cases in GC group, including 45 males and 8 females, with a median age of 63 (55, 69) years old. Thirty-one cases had a history of smoking. Thirty cases had an ECOG score of 0 and 23 cases had a score of 1, 48 cases suffered stage M 1, 2 cases suffered lymph node metastasis only. Nineteen cases suffered liver metastasis. Twenty-seven cases suffered lung metastasis. And 23 cases suffered bone metastasis. There was no statistically significant difference in the above general information between the two groups ( P>0.05). Kaplan-Meier method was used to plot the survival curves, and the difference of median progression-free survival (mPFS) and median overall survival (mOS) between the two groups was compared by log-rank test. Finally, the difference in adverse reactions between the two groups was compared. Results:The objective response rate (ORR) was 41.7% and the disease control rate (DCR) was 87.5% in the IGC group.As a comparison, the ORR was 43.4% and the DCR was 83.0% in the GC group. The differences in ORR ( P=0.887) and DCR ( P=0.871) between the two groups were not statistically significant. All patients were followed up for 3 to 45 months, with a median follow-up time of 24 (14, 43) months. The mPFS was 7.0 (95% CI 5.7-8.3) months in the GC group and 8.0 (95% CI 3.0-13.1) months in the IGC group, and the difference was statistically significant between the two groups ( P=0.026). The mOS of patients in the GC group was 16.0 (95% CI 14.4-17.6) months, the mOS was not yet reached in the IGC group, and patients in the IGC group had longer mOS with a statistically significant difference ( P=0.022). All patients experienced treatment-related adverse reactions. Grade 3-4 adverse reactions occurred in 8 cases (33.3%) in the IGC group and in 16 cases (30.2%) in the GC group, and no adverse reaction-related deaths were observed( P=0.992). The most common adverse reactions in both groups were anemia, including 18 cases (75.0%) in IGC group and 38 cases (71.7%) in GC group. There were 4 cases (16.7%) of grade 1-2 hypothyroidism in the IGC group but no patients with hypothyroidism were found in the GC group, and the difference was statistically significant ( P=0.012). There were 8 cases (33.3%) and 4 cases (7.5%) of grade 1-2 skin adverse reactions in the IGC and GC groups, respectively, and the difference was statistically significant ( P=0.011). The immune-related adverse reactions of PD-1 inhibitors in IGC group were 1 case of hyperthyroidism (4.2%), 4 cases of hypothyroidism (16.7%), 1 case of adrenal insufficiency (4.2%), and 1 case of immune colitis (4.2%). Conclusions:Compared with chemotherapy alone, PD-1 inhibitors combined with chemotherapy for metastatic bladder cancer can effectively prolong the mPFS and median mOS. The adverse reactions of the two groups were tolerable, and there was no significant difference in the incidence of grade 3-4 adverse reactions. In general, PD-1 inhibitors combined with chemotherapy in the treatment of metastatic bladder cancer is safe and feasible, but attention should be paid to the immune-related adverse reactions of PD-1 inhibitors.

Objective:To investigate the clinicopathological characteristics, treatment methods and prognosis of renal primary neuroendocrine neoplasms.Methods:The clinical data of 42 patients with renal neuroendocrine neoplasms admitted to the First Affiliated Hospital of Zhengzhou University from October 2011 to June 2021 were retrospectively analyzed.There were 17 males and 25 females. The median age was 60.0 (50.0, 67.0) years old.The CT enhancement scan lesion was slightly intensified with less intensification than normal renal parenchyma.The clinic manifestation included lumbar abdominal pain in 7 cases, hematuria in 3 cases, abdominal distension in 1 cases, and asymptomatic in 8 cases. The average diameter of tumor was 8.0 (4.0, 10.0) cm. The tumor of 13 cases was in the left, and 6 cases was in the right. 6 cases were in T 1 stage, 11 cases were in T 2, 11 cases were in T 3, and 14 cases were in T 4.17 cases had lymph node metastasis, 11 cases had distant metastasis.The surgical method was radical nephrectomy in 27 cases, nephrectomy in 5 cases and interventional embolization in 4 case, and no operation in 6 cases, including 5 with chemotherapy alone and 1 with supportive care.Patients were classified by WHO Classification of renal tumors of the urinary system and the male reproductive organs (2016) into high-differentiated renal neuroendocrine tumors (NET, including carcinoid and atypical carcinoids) and high-grade renal neuroendocrine carcinoma (NEC, including small cell neuroendocrine carcinoma and large cell neuroendocrine carcinoma). The clinicopathological characteristics and prognosis of the 2 groups were compared, and the Cox proportional regression risk model was used to analyze the clinical factors affecting the prognosis. Results:In the NET group, 12 cases were carcinoids and 7 cases were atypical carcinoids. In the NEC group, 23 cases were small cell carcinomas.The mean Ki-67 index of 42 cases was 35% (4.5%, 62.5%). The proportion of positive expression of the neuroendocrine markers CD56, chromogranin A (CgA), and synapsin (Syn) were (37/42), (15/42), and (38/42), respectively. A total of 42 patients were followed up, and the median follow-up time was 60 (35, 99) months, and the median survival time was 25 (15, 60) months. The 3-year and 5-year overall survival rates were 40.0% and 21.2%. The 3-year and 5-year overall survival rates in the NET group were 72.6% and 42.3%.The 3-year and 5-year overall survival rates in the NEC groups were 6.3% and 0, respectively. The mean Ki-67 index was 3% (2%, 10%) in the NET group, 2 patients received postoperative chemotherapy and 3 patients had early progression after initial treatment.The mean Ki-67 index in the NEC group was 60% (40%, 80%), 15 patients received postoperative chemotherapy, and 13 patients had early progression of initial treatment.There were statistically differences in treatment method, postoperative chemotherapy, Ki-67 index, and early disease progression (all P <0.05) between the two groups.The results of univariate analysis showed that sex, age, early progression, treatment method, tumor differentiation, and Ki-67 index were all factors influencing patient prognosis (all P <0.05). Cox multivariate analysis showed that poorly differentiated NEC ( HR=13.964, P=0.003) and early progression ( HR=3.626, P=0.018) were independent risk factors for patient survival, and renal radical surgery ( HR=0.197, P=0.033) was independent protective factors for patient survival. Further subgroup analysis showed that the median survival time of the NEC patients with adjuvant chemotherapy after surgery was significantly longer compared with the patients without adjuvant chemotherapy (21 and 9 months, P=0.012). Conclusions:Primary renal neuroendocrine tumors are clinically rare, often manifested as lumbar and abdominal pain, and radical renal surgical treatment is preferred.The NET has a better prognosis and NEC prognosis is extremely poor, but NEC patients can have survival benefit from chemotherapy. NEC and early progression of the disease are independent prognostic risk factors, and radical renal surgical treatment is an independent protective factor for prognosis.

【Objective】 Until now, most clinical and basic studies on Kashin-Beck disease (KBD) have focused on the visible deformed extremities, and there is a lack of reports concerning their spinal features, especially for the atlantoaxial joint. The purpose of this study was to determine the prevalence and radiographic features of atlantoaxial dislocation (AAD) in KBD in adult patients. 【Methods】 The prevalence and radiographic features of AAD were determined by the basic information collected, clinical symptoms, and lateral and dynamic plain radiography in 111 KBD patient and 120 non-KBD participants. In the KBD group, AAD and non-AAD patients were compared in age, gender, height, weight, BMI, smoking history, chronic history, disease duration and grade of disease so as to identify the related factors of the occurrence of AAD. 【Results】 Symptoms at the neck or neurological manifestations were present in 17.5% (21/120) in the non-KBD population and 39.6% (44/111) patients with KBD. AAD case was not detected in the non-KBD population, while in 16.2% (18/111) of KBD patients in the endemic area. The prevalence was higher in the KBD patients than in the non-KBD population, and there was a significant difference in the detection rate of AAD between the two groups (χ²=21.10, P<0.001). Plain radiography demonstrated that there were 10 (55.6%) cases with separation of the odontoid process and the other 8 (44.4%) cases with hypoplasia of odontoid process. Anterior AAD was noted in 12 (66.7%) patients and posterior AAD in 6 (33.3%) cases based on the displacement direction, while 16 (88.9%) cases were reducible and 2 (11.1%) cases were irreducible on the basis of the reducibility. Comparing the 93 patients with non-AAD KBD patients and 18 patients with AAD patients, there was no significant difference in age, sex, BMI, history of medical disease or smoking (all P>0.05). There were significant differences in height, weight, disease duration and grade of disease between AAD and non-AAD patients (all P<0.05). 【Conclusion】 KBD can cause the occurrence of atlantoaxial dislocation by inducing separation or hypoplasia of the odontoid process. This research may provide clinical evidence for screening, earlier prevention and treatment of atlantoaxial dislocation in adult KBD patients.