Injectable and In Situ Formed Dual-Network Hydrogel Reinforced by Mesoporous Silica Nanoparticles and Loaded with BMP-4 for the Closure and Repair of Skull Defects.

Bone defects are a common and challenging orthopedic problem with poor self-healing ability and long treatment cycles. The difficult-to-heal bone defects cause a significant burden of medical expenses on patients. Currently, biomaterials with mechanical stability, long-lasting action, and osteogenic activity are considered as a suitable way to effectively heal bone defects. Here, an injectable double network (DN) hydrogel prepared using physical and chemical cross-linking methods is designed. The first rigid network is constructed using methylpropenylated hyaluronic acid (HAMA), while the addition of chitosan oligosaccharide (COS) forms a second flexible network by physical cross-linking. The mesoporous silica nanoparticles (MSN) loaded with bone morphogenetic protein-4 (BMP-4) were embedded into DN hydrogel, which not only enhanced the mechanical stability of the hydrogel, but also slowly released BMP-4 to achieve long-term skull repair. The designed composite hydrogel showed an excellent compression property and deformation resistance. In vitro studies confirmed that the HAMA/COS/MSN@BMP-4 hydrogel had good biocompatibility and showed great potential in supporting proliferation and osteogenic differentiation of mouse embryo osteoblast precursor (MC3T3-E1) cells. Furthermore, in vivo studies confirmed that the DN hydrogel successfully filled and closed irregular skull defect wounds, effectively promoted bone regeneration, and significantly promoted bone repair compared with the control group. In addition, HAMA/COS/MSN@BMP-4 hydrogel precursor solution can quickly form hydrogel in situ at the wound by ultraviolet light, which can be applied to the closure and repair of wounds of different shapes, which provides the new way for the treatment of bone defects.

Application of Artificial Dermis Combined With a Medial Flap From the Second Toe to Repair Degloving Injury of the Fingertip.

There is no standard technique for repairing degloving injuries of the fingertip. Nail bed flap transplantation is a common surgical technique to address this injury, but this procedure inevitably damages the donor site in the toe. This article describes a surgical technique that can restore the appearance of the injured fingernail and preserve the length and function of the injured finger without damaging the toenail.

Forefoot Replantation in a 3-Year-Old Boy: Case Report.

Few reports about successful forefoot replantation in children have been published. In this article, we present a case of a 3-year-old boy with severe complete amputation of the left forefoot from a crushed and degloved injury in a motorcycle accident. The replantation was successfully performed, even though total ischemia time lasted 8 hours, of which 4 hours was cold ischemia time. The child was able to walk without significant difficulties from 4 months postoperatively and led a normal life in school at 2 years of follow-up. In this case, we present the replantation of a high-velocity traumatic partial foot amputation in a child with excellent function and cosmetic outcome.

Supermicrosurgery in fingertip defects-split tibial flap of the second toe to reconstruct multiple fingertip defects: A case report.

BACKGROUND: Injuries to multiple fingertips pose a significant treatment dilemma. Numerous reconstructive options exist, all with the ultimate goal of restoring function and sensibility to the injured fingertips. CASE SUMMARY: A 24-year-old male suffered injury to multiple fingertips of the right hand, resulting in exposed distal phalanges of the middle, ring, and small fingers. The amputated distal stumps were not possible for replantation. Free flap coverage was selected in order to achieve better functional outcome. The fingertip defects were covered by performing a right second toe split tibial flap using local anesthesia at the harvest site and brachial plexus nerve block for the right upper extremity. At 6-month follow-up, all three of the reconstructed fingertips had some preserved nail growth, Semmes-Weinstein Monofilaments testing was equal to the contralateral side and the Static Two-Point Discrimination were comparable to the contralateral side. CONCLUSION: This report provides a novel reconstructive option for the management of multiple fingertip injuries and demonstrates the utility of supermicrosurgery in management of these injuries.