Objective:To study the risk factors of metabolic bone disease (MBD) associated fracture in very low birth weight premature infants.Methods:From January 2012 to December 2019, premature infants (gestational age <32 weeks, birth weight <1 500 g) were admitted to our hospital and followed-up regularly for 1.5 years (once every month within first 6 months, then once every 3 months). The infants were assigned into two groups according to X-ray diagnosis: the fracture group and the non-fracture group. The clinical data of the two groups were compared and the risk factors of fracture were analyzed.Results:A total of 62 preterm infants with MBD were included in this study, including 11 in the fracture group and 51 in the non-fracture group. The risk factors of MBD associated fracture included intrauterine growth restriction (IUGR), birth weight <1 000 g, gestational age, respiratory support duration and total parenteral nutrition (TPN) duration ( P<0.05). Logistic regression analysis showed that IUGR ( P<0.05, OR=2.159, 95% CI 1.536~2.759) and TPN duration ( P<0.05, OR=1.143, 95% CI 1.042~1.270) were independent risk factors for fracture. Serum alkaline phosphatase (ALP) in the fracture group was significantly higher than the non-fracture group and 25(OH)VitD was significantly lower than the non-fracture group ( P<0.05). Conclusions:IUGR and TPN duration are risk factors for MBD associated fracture in preterm infants. As biochemical markers of bone metabolism, ALP and 25(OH)VitD levels have clinical value predicting MBD associated fracture.

Objective:To evaluate the effect of dexmedetomidine on the blood concentrations of ropivacaine during sciatic nerve block in rabbits.Methods:Twelve New Zealand rabbits of both sexes, weighing 2-3 kg, were randomly divided into ropivacaine group (R group) and ropivacaine mixed with dexmedetomidine group (RD group). The right femoral vein was cannulated for blood sampling in both groups, 0.375% ropivacaine 3 ml was injected around the left sciatic nerve in group R, and 0.375% ropivacaine 3 ml containing 1.5 μg/kg dexmedetomidine was injected instead in group RD.Blood samples from the right femoral vein were collected before nerve block (T 0) and at 15, 30, 45, 60, 120 and 180 min after nerve block (T 1-6) for determination of plasma concentrations of ropivacaine using high-performance liquid chromatography after centrifugation, and concentration-time curves were plotted. Results:Compared with group R, the blood concentrations of ropivacaine were significantly decreased at T 1-3 ( P<0.05), no significant change was found in the blood concentrations of ropivacaine at T 4-6 ( P>0.05), the peak blood concentration of ropivacaine was significantly decreased ( P<0.01), and no significant change was found in the time to peak blood concentrations of ropivacaine or area under the concentration-time curves in group RD ( P>0.05). Conclusions:Dexmedetomidine can decrease the blood concentrations of ropivacaine during sciatic nerve block in rabbits.

Objective The aim of this study was to explore the impact of implant robots on the oral func-tion and aesthetic effects of immediate implant patients in the aesthetic area of anterior teeth.Methods A total of 68 patients with single anterior tooth defects admitted to the hospital from January 2021 to January 2023 were enrolled and divided into a study group of 34 cases and a control group of 34 cases randomly.In the study group,anterior tooth immediate implantation was performed with the assistance of an oral implantation robot,while the control group underwent conventional immediate anterior tooth implantation.The implantation accuracy,postopera-tive bite function,aesthetic restoration,and occurrence of complications were compared between the two groups,and complications were all recorded.Results After final restoration,all patients were followed up for 2 years,and the implant success rate was 100%(68/68 cases).The study group exhibited significantly lower postoperative apical point error and implant angle error compared to the control group(P＜0.05).There was no significant differ-ence in speech clarity,bite pressure,and pain intensity between the two groups(P＞0.05).The ratio of implant bite pressure to that of the contralateral homonymous tooth was higher in the study group than in the control group(P＜0.05).The postoperative pink esthetic score(PES)and white esthetic score(WES)in the study group were higher than those in the control group(P＜0.05).There was no statistically significant difference in the incidence of complications between the two groups(P＞0.05).Patient satisfaction in the study group was higher than that in the control group(P＜0.05).Conclusion The use of oral implantation robots for immediate implantation in the aesthetic zone of anterior teeth resulted in higher intraoperative positioning accuracy and yielded favorable outcomes in postoperative restoration of bite function and aesthetics.