Recent progress in vestibular prosthesis / 临床耳鼻咽喉头颈外科杂志

Bilateral vestibulopathy（BVP） is one of the common diseases in the vestibular nervous system, with an incidence rate of about 4%-7% in the population, which can lead to a variety of body dysfunctions. At present, there are two main treatment methods for BVP. One is vestibular rehabilitation. However, only part of BVP patients can finally benefit from vestibular rehabilitation, and most patients will remain with permanent vestibular dysfunction. Benefiting from the maturity of cochlear implant technology, European and American countries took the lead in the development of vestibular prosthesis（VP） technology to restore the vestibular function in patients with BVP. This review will focus on the development history, principles, future applications and the related research progress of VP in China.

Stochastic discrete epidemic modeling of COVID-19 transmission in the Province of Shaanxi incorporating public health intervention and case importation

Before the lock-down of Wuhan/Hubei/China, on January 23rd 2020, a large number of individuals infected by COVID-19 moved from the epicenter Wuhan and the Hubei province due to the Spring Festival, resulting in an epidemic in the other provinces including the Shaanxi province. The epidemic scale in Shaanxi was comparatively small and with half of cases being imported from the epicenter. Based on the complete epidemic data including the symptom onset time and transmission chains, we calculate the control reproduction number (1.48-1.69) in Xian. We could also compute the time transition, for each imported or local case, from the latent, to infected, to hospitalized compartment, as well as the effective reproduction number. This calculation enables us to revise our early deterministic transmission model to a stochastic discrete epidemic model with case importation and parameterize it. Our model-based analyses reveal that the newly generated infections decay to zero quickly; the cumulative number of case-driven quarantined individuals via contact tracing stabilize at a manageable level, indicating that the intervention strategies implemented in the Shaanxi province have been effective. Risk analyses, important for the consideration of "resumption of work", show that a large second outbreak is expected if the level of case importation remains at the same level as between January 10th and February 4th 2020. However, if the case importation decreases by 30%, 60% and 90%, the second outbreak if happening will be of small-scale assuming contact tracing and quarantine/isolation remain as effective as before. Finally, we consider the effects of intermittent inflow with a Poisson distribution on the likelihood of multiple outbreaks. We believe the developed methodology and stochastic model provide an important model framework for the evaluation of revising travel restriction rules in the consideration of resuming social-economic activities while managing the disease control with potential case importation.

Morphological differences of proximal femoral medullary cavity in elderly patients and its effect on proximal femoral nail fixation / 中华创伤杂志

Objective To investigate the morphological differences of proximal femoral medullary cavity in elderly patients with intertrochanteric fracture and its effect on the treatment efficacy of proximal femoral nail antirotation (PFNA). Methods A retrospective case series study was conducted on the clinical data of 112 elderly patients with intertrochanteric fracture of the femur from December 2012 to January 2017, including the preoperative and postoperative hip joints orthotopic X ray (including the proximal femur), lateral X ray, and pelvic orthotopic X ray films. The proximal femoral canal flare index (CFI) and the metaphyseal canal flare index (MCFI) were measured. The proportion of patients with different types of medullary cavity and the gender difference were analyzed according to Dorr typing. The fractures were classified according to the modified Evans classification. Operation time, fracture reduction quality, tip apex distance (TAD), incidence of intraoperative split fracture around the rotors, postoperative fracture reduction loss rate, weight bearing time, and fracture healing time were recorded. Results The proximal femoral canal flare index (CFI) was significantly correlated with the intramedullary diameter above the lesser trochanter, the inner diameter of the affected side medullary cavity isthmus, and metaphyseal canal flare index (MCFI) (P ＜0.01). There was clear difference in gender in terms of the medullary cavity diameter 20 mm above the middle point of lesser trochanter, medullary isthmus internal diameter, the medullary cavity diameter 20 mm below the middle point of lesser trochanter, CFI, and MCFI. Thereinto, there was significant difference in the medullary cavity diameter 20 mm above the middle point of lesser trochanter [male (52.6 ± 6.4) mm, female: (49.9 ± 5.4) mm], the medullary cavity diameter 20 mm below the middle point of lesser trochanter [male: (26.5 ± 3.7) mm, female: (23.1 ±2.8)mm], and MCFI (male:2.0 ±0.3, female:2.2 ±0.2). No significant difference between the medullary isthmus internal diameter and CFI was found (P＞0.05). In this group, the medullary cavity of proximal femur was classified by Dorr: the proportion of funnel type, normal type, and chimney type was 5.4％ (6/112), 73.2％ (82/112), and 21.4％ (24/112), respectively. There was no significant difference in the modified Evans fracture stability among different morphological types of the proximal femoral medullary cavity. The difference of weight bearing time between normal group and chimney group was statistically significant [normal type: (21.4±16.9)d, chimney type: (45.5 ± 11.2)d] (P ＜ 0.05), but there were no significant differences in operation time, reduction quality, TAD, intraoperative incidence of cleavage fracture incidence, reduction loss rate, and healing time between the two groups (P＞0.05). Conclusions The occurrence and development of osteoporosis can cause significant changes in the morphology of proximal femoral medullary cavity, mainly manifesting as the gradual increase of the proportion of chimney type. The efficacy of PFNA in treatment of the intertrochanteric fracture is satisfactory. However, the risk of intraoperative cleavage fracture and postoperative reduction loss should be taken seriously.

In vitro study on physical and chemical properities of calcium phosphate cement/amifostine complex and on vitality of cultured cells / 生物医学工程学杂志

This study was designed to assess the feasibility of calcium phosphate cement/amifostine complex as a new material for filling the bone defect caused by tumor resection. Mixed-molding method was used, the mass ratios of 0%, 0.1%, 0.5%, 1%, 2% of amifostine/calcium phosphate cement complex being adopted. The curing time, mechanical strength, porosity, scanning electron micrograph, osteosarcoma cells' vitality and vascular endothelial cells' vitality relevant to the complex in vitro were observed. Calcium phosphate cement being loaded with 0.1% and 0.5% amifostine did not affect the curing time, strength, pore size and porosity of calcium phosphate bone cement. In addition proliferation and differentiation of osteosarcoma cells and vascular endothelial cells were not affected. These data suggest that phosphate cement containing 0.1% and 0.5% amifostine be of significance in the treatment regimen as bone defect filling materials..

Drug delivery of CPC/cisplatin complex in vitro and its ability to repair bone defect and eliminate tumor in vivo / 中南大学学报(医学版)

Objective To explore the best mass ratio of calcium phosphate cement (CPC) / cisplatin complex filling and to repair bone defect caused by tumor resection. Methods Mixed-molding method was used to obtain cisplatin/calcium phosphate cement complex at 0, 0.1%, 0.2%, and 0.4% mass ratio. Drug concentration was determined by atomic absorption spectrophotometry. Bone defect of rabbits and osteosarcoma of rats were prepared. We implanted CPC and CPC/cisplatin complex to observe the repair of bone defect and the inhibition of tumor in vivo. Results CPC containing 0.1% ～ 0. 2 % cisplatin not only repaired the bone defect in rabbits but also eliminated osteosarcoma in rats. Conclusion CPC containing 0.1% ～ 0. 2 % cisplatin can repair bone defect and eliminate tumor without influencing the prosthetic precess.