A Rare Case of Craniocervical Penetrating Injury by a Steel Bar.

RATIONALE: Non-missile penetrating injuries caused by foreign bodies, such as knives or sharp wood, are infrequent. We report a 49-year-old male suffering from severe craniocervical penetrating injury by a steel bar was successfully treated by surgery. CHIEF COMPLAINT: The male patient was a 49-year-old builder. Although working on the construction site, an approximately 60 cm steel bar penetrated the patient's brain vertically through the left top of the head presenting with unconsciousness and intermittent irritability. DIAGNOSIS: Computed tomography of the head showed the entrance and exit of the skull damaged by the steel bar. Three-dimensional reconstruction showed that the steel bar entered the skull from the posterior left coronal suture and penetrated the ipsilateral occipital bone, about 5 cm into the neck soft tissue. INTERVENTION: We successfully performed the operation and removed the steel bar. OUTCOMES: The patient was followed up for 5 years; muscle strength returned to normal. LESSONS: Penetrating injuries caused by steel bars are rare, which always cause severe intracranial injury combined with peripheral tissue injury, by sharing our experience in the treatment of this rare case, we hope to provide a reference for similar injuries in the future.

In-situ re-melting and re-solidification treatment of selective laser sintered polycaprolactone lattice scaffolds for improved filament quality and mechanical properties.

Selective laser sintering (SLS) is a promising additive manufacturing technique that produces biodegradable tissue-engineered scaffolds with highly porous architectures without additional supporting. However, SLS process inherently results in partially melted microstructures which significantly impair the mechanical properties of the resultant scaffolds for potential applications in tissue engineering and regenerative medicine. Here, a novel post-treatment strategy was developed to endow the SLS-fabricated polycaprolactone (PCL) scaffolds with dense morphology and enhanced mechanical properties by embedding them in dense NaCl microparticles for in-situ re-melting and re-solidification. The effects of re-melting temperature and dwelling time on the microstructures of the SLS-fabricated filaments were studied. The results demonstrated that the minimum requirements of re-melting temperature and dwelling time for sufficient treatment were 65 °C and 5 min respectively and the size of the SLS-fabricated filaments was reduced from 683.3 ± 28.0 µm to 601.6 ± 17.4 µm. This method was also highly effective in treating three-dimensional (3D) PCL lattice scaffolds, which showed improved filament quality and mechanical properties after post-treatment. The treated PCL scaffolds with an initial compressive modulus and strength of 3027.8 ± 204.2 kPa and 208.8 ± 14.5 kPa can maintain their original shapes after implantation in vivo for 24 weeks. Extensive newly-grown tissues were found to gradually penetrate into the porous regions along the PCL filaments. Although degradation occurred, the mechanical properties of the implanted constructs stably maintained. The presented method provides an innovative, green and general post-treatment strategy to improve both the filament quality and mechanical properties of SLS-fabricated PCL scaffolds for various tissue engineering applications.