An Extremely Rare Case of Cementless Third Generation Corail Stem Neck Fracture With Fractographic Analysis.

The cementless Corail stem is one of the most frequently implanted stems and has undergone several design changes. Currently in use is the third generation, named Corail AMT. Until now, only one third-generation Corail stem neck fracture has been described in 2020. In our paper, we present an almost identical complication with an additional analysis of the fracture using a scanning electron microscope. The revision surgery consisted of changing the broken implant with a Corail revision stem, along with replacing the polyethylene liner and the femoral head with new one, after which the patient achieved a full recovery. According to the available literature, this is the second case of this extremely rare complication.

How to treat jatrogenic ureteral injury after posterior spinal surgery? Case report and review of literature.

Introduction: Entry into the retroperitoneal space during open posterior spinal surgery introduces the rare possibility of iatrogenic ureteral injury. Case presentation: We describe a case of ureteral injury after spinal surgery in a 49-year-old female with persistent lumbar pain and high fever 2 weeks after spinal surgery. After admission to the urology department, a computer tomography scan was performed and revealed right-side hydronephrosis grade III and large retroperitoneal fluid collection. After radiological confirmation of right ureteral injury, a ureteral stent was placed, but 4 weeks later, ureteral stricture was confirmed on antegrade pyelography. Therefore, surgical ureteroplasty was indicated 2 months after initial admission to the urology department. Six weeks later, the stent was removed, and intravenous pyelography revealed a normal ureteral passage. Conclusion: There should be a low threshold for ureteral injuries after spinal cord surgery in patients with high fever and elevated blood creatinine levels.

Determining the Role of Acicular Ferrite Carbides in Cleavage Fracture Crack Initiation for Two Medium Carbon Microalloyed Steels.

Two medium-carbon microalloyed steels with a predominant acicular ferrite microstructure were investigated in this study in order to determine the initial micro-crack formation mechanism and the role of acicular ferrite structure in cleavage fracture. In order to ensure cleavage fracture, samples were investigated at -196 °C for uniaxial tension and four point bending fracture. Previous investigations have shown that cleavage fracture for steels with a predominant acicular ferrite microstructure has not been initiated by the fracture of coarse TiN particles as in ferrite-pearlite, bainite, or martensitic microalloyed steels. The average maximal thickness of cementite plates measured in this work is 0.798 µm and 0.966 µm, for V and TiV steel, respectively. The corresponding stress values required for their fracture according to Griffith's equation are 1970 MPa and 1791 MPa, respectively. Estimated values of the effective surface energy for the V steel with an average cementite volume fraction of 3.8% range from 40 Jm-2 to 86 Jm-2, and for the TiV steel with an average cementite volume fraction of 18.3% range from 55 Jm-2 to 82 Jm-2. The fracture of coarse cementite plates was found to not to be responsible for the cleavage fracture initiation in case of both steels.

Cleavage Fracture of the Air Cooled Medium Carbon Microalloyed Forging Steels with Heterogeneous Microstructures.

Cleavage fracture of the V and Ti-V microalloyed forging steels was investigated by the four-point bending testing of the notched specimens of Griffith-Owen's type at -196 °C, in conjunction with the finite element analysis and the fractographic examination by scanning electron microscopy. To assess the mixed microstructure consisting mostly of the acicular ferrite, alongside proeutectoid ferrite grains and pearlite, the samples were held at 1250 °C for 30 min and subsequently cooled instill air. Cleavage fracture was initiated in the matrix under the high plastic strains near the notch root of the four-point bending specimens without the participation of the second phase particles in the process. Estimated values of the effective surface energy for the V and the Ti-V microalloyed steel of 37 Jm-2 and 74 Jm-2, respectively, and the related increase of local critical fracture stress were attributed to the increased content of the acicular ferrite. It was concluded that the observed increase of the local stress for cleavage crack propagation through the matrix was due to the increased number of the high angle boundaries, but also that the acicular ferrite affects the cleavage fracture mechanism by its characteristic stress-strain response with relatively low yield strength and considerable ductility at -196 °C.