Virtual reality technology and force feedback technology are novel human-machine interaction technologies. The virtual surgery simulation training system combined with these two technologies provides a new method for orthopedic surgery training, which can improve the training efficiency,thereby reducing the training costs and shortening the growth cycle of young orthopedic surgeons. In recent years, the virtual drilling bone surgery simulation technology have been researched broadly and obtained a preliminary application. In this paper, the existing research statusof virtual bone drilling operation depended on visuo-haptic techniques were studied, classified and summarized, the main content focused on three key techniques: bone modeling, drilling bone force prediction model and tactile simulation, and then analyzed the advantages and disadvantages of existing methods. Finally,some perspectives for related technology development trend of the virtual simulation bone drilling surgery in future was pointed out.

OBJECTIVETo observe the long-term efficacy and safety of telbivudine (LdT) for pregnant women with chronic hepatitis B (CHB) and their children born from the treatment period.

METHODSA total of 118 pregnant women with CHB were enrolled in the study and provided informed consent for participation. The women opted for participation in the treatment group (7 =73; LdT 600 mg once daily, starting in early pregnancy and continued until after delivery) or in the control group (n =45; no LdT treatment). All newborns were given active and passive immunization upon birth and tested for serum hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), anti-hepatitis B core antibody (anti-HBc), anti-hepatitis B surface antibody (anti-HBs) and HBV DNA at 0, 1, 7 and 12 months of age. The Paediatrics Neuropsychological Development Scale for Children aged 0 - 6 (5 items) established by the Capital Institute was used to test the children; in addition, the children were evaluated by observation for action ability (fine and gross motor skills), adaptability, language ability and social behaviour. Total IQ was estimated as a developmental quotient (DQ) by using the equation: points from the 5 scale items actual age in months * 100.

RESULTSThe LdT group included 69 women with successful pregnancies, 1 case of miscarriage and 3 cases that were lost to follow-up. The control group included 34 women with successful pregnancies, 4 cases of miscarriage, 1 case with fatal outcome, and 6 cases of no pregnancy. Compared to the control group, the LdT group had a significantly higher successful pregnancy rate (x² =4.86 in the LdT group, P < 0.05). In addition, the LdT group had a significantly higher rate of term delivery (53 cases vs. 34 cases, x² = 6.38, P < 0.05). The neonates born to the women in the LdT group included 53 cases of weakly-negative HBsAg at birth and 1 case at 1 month old, as well as negativity for HBV DNA, and HBsAg remaining weakly positive at 6 months old; the intrauterine infection rate was 1.8% and no case of deformity occurred.Among the 34 neonates in the control group, 6 showed HBsAg positivity at 1 month old, and the HBsAg positivity remained for all 6 at 6 months old; the intrauterine infection rate was 16.6%, which was significantly higher than that of the LdT group (x² = 5.10, P < 0.05). The neonates in the LdT group had a significantly higher anti-HBs production rate at 1 year old than those in the control group (98.1% (52/53 vs. 82.4% (28/34). X² = 4.87, P < 0.05). The neonates in the LdT group showed normal growth and development for all 53 cases of young children, and IQ levels of excellent for 3 cases, smart for 8 cases, normal for 40 cases, and low for 2 cases. The neonates in the control group showed normal growth and development for all 34 cases of young children, and IQ levels of excellent for 2 cases, smart for 4 cases, normal for 27 cases, and low for 1 case.

CONCLUSIONChildbearing chronic HBV patients treated with LdT had higher rates of successful pregnancy, blocking of intrauterine infection and anti-HBs reduction compared to their untreated counterparts. The children bom to LdT-treated women showed no difference in long-term growth and development and total IQ from the children born to the untreated women with chronic HBV.

Adolescent ; Adult ; Antiviral Agents ; adverse effects ; therapeutic use ; Female ; Hepatitis B, Chronic ; drug therapy ; Humans ; Infant ; Infant, Newborn ; Infectious Disease Transmission, Vertical ; prevention & control ; Pregnancy ; Pregnancy Complications, Infectious ; drug therapy ; Thymidine ; adverse effects ; analogs & derivatives ; therapeutic use ; Young Adult