Search

Objective: To evaluate the preliminary outcomes of tetrafocal (three osteotomies) and pentafocal (four osteotomies) bone transport using Ilizarov technique for the treatment of distal tibial defect and describe the surgical technique.Methods: A total of 12 eligible patients with distal tibial defect > 6 cm caused by direct trauma or posttraumatic osteomyelitis who were admitted to our institution from January 2017 to January 2019 were treated by tetrafocal or pentafocal bone transport using Ilizarov technique. Detailed demographic data, including age, sex, etiology, defect size, number of osteotomies (three or four), external fixation time (EFT) and external fixation index (EFI), were collected, and the bone and functional outcomes were evaluated by the Association for the Study and Application of the Method of Ilizarov (ASAMI) scoring system. Complications during the surgery and the follow-up period were recorded and evaluated by the Paley classification at a minimum follow-up of two years after removal of the fixator.Results: There were 9 men and 3 women with an average age of 37.4±7.8 years. The etiology included posttraumatic osteomyelitis in 8 cases and posttraumatic bone loss in 4 cases. The mean bone defect after radical debridement was 7.1±0.6 cm. Tetrafocal bone transport was applied in 9 cases, and pentafocal bone transport was applied in 3 cases. The average EFT and EFI were 5.2±0.8 months and 0.7±0.2 months/cm, respectively. The average time of follow-up after removal of the external fixator was 28.5±3.3 months without recurrence of osteomyelitis. The bone results were good in 7 cases, fair in 4 cases, and poor in 1 case, and the functional results were good in 5 cases, fair in 6 cases, and poor in 1 case. The most common complication was pin tract infection, which occurred in all cases, but there were no major complications, such as nerve or vascular injury.Conclusion: Tetrafocal and pentafocal bone transport using Ilizarov technique could be an alternative treatment option in selected cases with distal tibial defect > 6 cm. It could shorten the distraction period, fasten regeneration, and reduce the associated complications. [ABSTRACT FROM AUTHOR]

The intermingling of regenerated nerve fibers inside nerve grafts is the main reason for mismatched nerve fibers. This is one of the key factors affecting limb function recovery after nerve injury. Previous research has shown that the accuracy of axon regeneration can be improved by a bionic structural implant. To this aim, iodine and freeze-drying high-resolution micro-computed tomography was performed to visualize the 3D topography of the New Zealand rabbit sciatic nerve (25 mm). A series of 1-, 2-, 3-, and 4-custom anatomy-based nerve conduits (CANCs) were fabricated based on the anatomical structure of the nerve fascicle. The match index, luminal surface, and mechanical properties of CANCs were evaluated before implanting in a 10-mm gap of the sciatic nerve. Recovery was evaluated by histomorphometric analyses, electrophysiological study, gastrocnemius muscle weight recovery ratio, and behavioral assessments at 12 and 24 weeks postoperatively. The accuracy of nerve regeneration was determined by changes in fluorescence-labeled profile number during simultaneous retrograde tracing. Our results showed that the optimal preprocessing condition for high-resolution micro-computed tomography visualization was treatment of the sciatic nerve with 40% Lugol's solution for 3 days followed by lyophilization for 2 days. In vitro experiments demonstrated that the match index was highest in the 3-CANC group, followed by the 2-, 1-, and 4-CANC groups. The luminal surface was lowest in the 1-CANC group. Mechanical properties (transverse compressive and bending properties) were higher in the 3- and 4-CANC groups than in the 1-CANC group. In vivo experiments demonstrated that the recovery (morphology of regenerated fibers, compound muscle action potential, gastrocnemius muscle weight recovery ratio, pain-related autotomy behaviors, and range of motion) in the 3-CANC group was superior to the other CANC groups, and achieved the same therapeutic effect as the autograft. The simultaneous retrograde tracing results showed that the percentages of double-labeled profiles of the 2-, 3-, and 4-CANC groups were comparatively lower than that of the 1-CANC group, which indicates that regenerated nerve fascicles were less intermingled in the 2-, 3-, and 4-CANC groups. These findings demonstrate that the visualization of the rabbit sciatic nerve can be achieved by iodine and freeze-drying high-resolution micro-computed tomography, and that this method can be used to design CANCs with different channels that are based on the anatomical structure of the nerve. Compared with the 1-CANC, 3-CANC had a higher match index and luminal surface, and improved the accuracy of nerve regeneration by limiting the intermingling of the regenerated fascicles. All procedures were approved by the Animal Care and Use Committee, Xinjiang Medical University, China on April 4, 2017 (ethics approval No. IACUC20170315-02)., Competing Interests: None

Osteosarcoma is the most common bone cancer in children and adults. However, its pathogenesis, especially molecular mechanisms remain elusive. In current study, we screened GEO Database and found a poorly studied protein Neurensin-2 (NRSN2), which is highly expressed in osteosarcoma tissues. Neurensin-2 (NRSN2) is a small neuronal membrane protein and localized in small vesicles in neural cells, previous study found that it has been implicated in hepatocellular carcinoma (HCC) and non-small cell lung cancer (NSCLC). We here report that the expression of NRSN2 is more commonlyelevated in 18 fresh osteosarcoma tissues. Furthermore, both loss- and gain-functions assays revealed that NRSN2 could promote osteosarcoma cell proliferation and growth both in vitro and in vivo. In addition, we further found that those effects on osteosarcoma by NRSN2 are associated with the dysregulated PI3K/AKT/mTOR signaling and Wnt/β-catenin signaling. In conclusion, our study found a novel oncogenic protein, NRSN2, which promotes osteosarcoma cell proliferation and as a membrane protein, NRSN2 also could be a potential treatment target for osteosarcoma.