BACKGROUND: With the development of nanotechnology, silk fibroin/nano-hydroxyapatite composite materials used for tissue repair have been reported; however, there are few reports on its use in spinal stability.OBJECTIVE: To explore the feasibility of silk fibroin/nano-hydroxyapatite composite materials for the initial segmental stability of the reconstructed spine.METHODS: Thirty-six New Zealand rabbits were randomly divided into three groups, and the L4/5 nucleus pulposus was removed in all the animals. Autologous bone group was implanted with autologous bone, experimental group implanted intervertebrally with silk fibroin/nano-hydroxyapatite composite material, and control group implanted with hydroxyapatite.At 12 weeks after implantation, lumbar interbody fusion was observed using X-ray, the spinal stability of the fusion segments was measured by biomechanical test, and histologically, bone graft fusion and material degradation at the surgical site were observed.RESULTS AND CONCLUSION: (1) X-ray observation: In the autologous bone group, the experimental group and the control group, there were respectively 11, 7, 2 rabbits meeting the standard of fusion. (2) Biomechanical test: The spinal activity during flexion-extension was significantly lower in the experimental group than the autogenous bone group and control group (P < 0.05). (3) Histological observation: Bony union was found at the junction between the iliac bone and surrounding tissues in the autologous bone group, and a large number of bone cells and fibroblasts were found around the new bone, while woven bone was found inside. The material was partially degraded in the experimental group,fibrous tissues were visible in the surrounding tissue, new woven bone was found inside, and pit cells and bone cells were scattered. Blood vessel growth around the material was visible in the control group, and a large number of macrophages were found inside the material. To conclude, the silk fibroin/nano-hydroxyapatite composite material has good biocompatibility and mechanical properties, which could rebuild the initial segmental stability in the rabbit spine in the short time.

Objective:To explore the clinical characteristics of children with Streptococcus pneumoniae cellulitis. Methods:The bacterial culture information management system in 18 children′s hospitals from January 2012 to December 2017 were reviewed.Among 1 138 children diagnosed with invasive pneumococcal disease(IPD), 7 cases were hospitalized with cellulitis.Clinical information was collected and analyzed.Results:Seven cases of Streptococcus pneumoniae cellulitis accounted for 0.6%(7/1 138 cases) of 1 138 IPD cases in 18 hospitals.There were 5 males and 2 females.The onset age was from 1 month to 6 years old, and the median age was 2 years old.There were 4 cases in rural areas and 3 cases in urban areas.Langerhans cell histiocytosis (LCH) was found in 1 case.Clinical manifestations: fever, local swelling and pain with infection.The focus of cellulitis: orbital cellulitis in 2 cases, buccal infection in 2 cases, upper extremity, head and buttock infection in 1 case, respectively.At the beginning of the disease: 2 cases of orbital cellulitis were accompanied by nasosinusitis and suppurative otitis media, 1 case was treated with acute periapical inflammation, 1 case was 10 months after chemotherapy.Type of infection: 6 cases were complicated with bloodstream infection, 2 cases with bacterial meningitis and 1 case with pneumonia.Other culture results: 6 cases of Streptococcus pneumoniae were cultured in peripheral blood, 2 cases were positive in local pus culture.Drug sensitivity test: 6 cases were sensitive to Penicillin and Cephalosporin (Cefotaxime/Ceftriaxone), 1 case was resistant.Treatment: 3 patients were treated with Cephalosporins alone, 2 cases with Cephalosporins and Penicillins, 2 cases with Vancomycin and Meropenem for meningitis, 3 cases with local abscess by incision and drainage, 2 cases with meningitis in Intensive Care Unit, and 1 case with endotracheal intubation and ventilator assisted ventilation.The average length of stay was 14.3 days(5-41 days). Discharge outcome: 6 cases improved and 1 case died. Conclusions:Cellulitis is a rare type of infection in children with IPD.It is mainly found in the head, face and around the orbit.It may be accompanied by bloodstream infection or bacterial meningitis.Most of them have a good prognosis.

Objective:To investigate the clinical features, diagnosis, treatment and prognosis of children with osteomyelitis caused by Streptococcus pneumonia. Methods:The demographic characteristics, diagnosis, clinical manifestations, imaging features, treatment and short-term prognosis of Streptococcus pneumonia osteomyelitis cases in 18 children′s hospitals from January 2012 to December 2017 were retrospectively collected and analyzed. Results:A total of 9 cases were enrolled, with a median age of 1 year and 3 months.Four children had underlying diseases.The main manifestations were local swelling, pain, limited mobility (9 cases) and fever (8 cases). Sites of infection included humerus (4 cases), femur (3 cases) and tibiofibula (2 cases), and 8 cases were complicated with septic arthritis; The laboratory tests showed increased white blood cells (8 cases, median 22.02×10 9/L), C-reactive protein (7 cases, median 55.44 mg/L) and erythrocyte sedimentation rate (6 cases, median 70 mm/1 h) of those patients.Five patients received monotherapy in the initial treatment regimen with cephalosporins. Then the therapeutic schedules were adjusted according to the culture and antibiotic sensitivity. All patients were treated with puncture, incision drainage or fenestrating decompression.Eight patients were cured and discharged finally. Conclusions:Streptococcus pneumonia osteomyelitis is more common in younger children and may have no risk factors.The common infection site is long bone metaphysis, and those patients are easily complicated with septic arthritis.Antibiotic combined with surgical treatment are crucial to a good outcome.