[C2 pedicle screw insertion assisted by mobilization of the vertebral artery in cases with high-riding vertebral artery].

Objective: To examine the feasibility, safety, and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with high-riding vertebral artery (HRVA). Methods: The clinical data of 12 patients with basilar invagination and atlantoaxial dislocation underwent atlantoaxial reduction and fixation in the Department of Neurosurgery, the First Affiliated Hospital of University of Science and Technology of China between January 2020 and November 2021 were retrospectively analyzed. All patients had high-riding vertebral artery on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 10 females aged (48.0±12.8) years (range: 17 to 67 years). After correction of vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including the anterior atlantodental interval (ADI), the distance of the odontoid tip above the Chamberlain line, the clivus-canal angle, were collected and compared by paired t-test. Results: Mobilization of the high-riding vertebral artery was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were achieved in all 12 patients. All patients achieved bone fusion 6 months after surgery. No looseness and shift in internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative ADI decreased from (6.1±1.9) mm to (2.0±1.2) mm (t=6.73, P<0.01), the distance of the odontoid tip above the Chamberlain line decreased from (10.4±2.5) mm to (5.5±2.3) mm (t=7.12, P<0.01), the clivus-canal angle increased from (123.4±11.1) ° to (134.7±9.6) ° (t=2.50, P=0.032), the JOA score increased from 13.3±2.1 to 15.6±1.2 (t=6.99, P<0.01). Conclusion: The C2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.

Molecular diversity and distribution of anammox community in sediments of the Dongjiang River, a drinking water source of Hong Kong.

AIMS: The aim of this study was to characterize anaerobic ammonium oxidation (anammox) community in sediments of the Dongjiang River, a drinking water source of Hong Kong. METHODS AND RESULTS: The diversity and distribution of the anammox community were investigated based on a comparative analyses of 16S rRNA and hydrazine oxidation (hzo) genes of anammox bacteria. Candidatus Brocadia and two new anammox bacterial clusters were detected based on phylogenetic analysis of 16S rRNA genes. In contrast, the targeting of hzo genes indicated the presence of only Candidatus Jettenia with four different clusters. It was found that the sequence diversities of hzo genes were higher than those of the 16S rRNA genes. The abundance of anammox bacteria varied significantly among the sediment samples based on qPCR. Pearson correlation analysis indicated that nitrite concentration was the key factor influencing the abundance of anammox bacteria. The redundance analysis (RDA) confirmed that the combination of the contents of nitrite and nitrate, and the ratio of total nitrogen vs total carbon (TN/TC) had significant impact on the anammox bacterial community structure. CONCLUSIONS: The results revealed that the diverse anammox bacteria were present in sediments of the Dongjiang River, and the community structures were associated with varied environmental factors caused by urban pollutant invasion. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first report about the distribution of anammox bacterial community in sediments of the Dongjiang River, which provides helpful information of anammox niche specificity and influencing factors in the river ecosystem.

Pediatric cerebrovascular diseases: report of 204 cases.

OBJECTIVE: To investigate the epidemiology of pediatric cerebrovascular diseases. METHODS: Retrospective review of clinical data for 204 pediatric patients under the age of 18 treated for cerebrovascular disease at Huashan Hospital within the past 13 years. RESULTS: Mean age was 12.7 years and male-to-female ratio was 1.91:1. Onset of symptoms was acute or subacute in 73.5% (150/204). Main clinical manifestations include: headaches (70.6%), vomiting (50.0%), loss of consciousness (22.5%), convulsions (21.6%), and focal neurological deficits (13.2%). The most common etiologies were: arteriovenous malformations (42.2%; 86/204), cavernomas (16.2%; 33/204), aneurysms (8.8%; 18/204), and Moyamoya disease (5.9%; 12/204). The cause remained unknown in 21% (43/204). CONCLUSIONS: As the main neurological medical center in the southern part of China, the statistics of Huashan Hospital could be representative. The epidemiology of pediatric cerebrovascular diseases has its own specificity. Pediatric cerebrovascular disease must be diagnosed in a timely manner and treated urgently, according to the distinct clinical features of the pediatric patient.