Acute fatal group A Streptococcal primary peritonitis following vaginal delivery.

Acute primary peritonitis due to group A streptococci (GAS) is a rare but life-threatening disease most often seen in case of liver cirrhosis or nephrotic syndrome. The specific mechanism of this infection remains unknown and according to the literature hematogenous, lymphatic, retrograde inoculation from the genitourinary tract and translocation of intestinal tract flora have all been proposed. We report a case of a 37-year-old previously healthy patient who presented to the emergency, four days after vaginal delivery, with abdominal pain and septic shock. Acute peritonitis was diagnosed and peritoneal and blood culture revealed group A streptococci. Unfortunately, the patient died within 12 h despite adequate resuscitation and antimicrobials. The present case report highlights the importance of an early diagnosis with an adequate therapy in case of GAS peritonitis after vaginal delivery.

A comparative study of tapped and untapped pilot holes for bicortical orthopedic screws - 3D finite element analysis with an experimental test.

The aim of this study was to compare the screw-to-bone fixation strength of two insertion techniques: self-tapping screw (STS) and non-self-tapping screw (NSTS). Finite element analysis (FEA) was used for the comparison by featuring three tests (insertion, pull-out and shear) in a human tibia bone model. A non-linear material behavior with ductile damage properties was chosen for the modeling. To validate the numerical models, experimental insertion and pull-out tests were carried out using a synthetic bone. The experimental and numerical results of pull-out tests correlated well. Thread forming was successfully simulated during the insertion process of STS and NSTS. It is demonstrated that the STS generates higher insertion torque, induces a higher amount of stress after the insertion process and relatively more strength under the pull-out and shear tests than the NSTS. However, the NSTS induces more stiffness under the two tests (pull-out and shear) and less damage to the screw-bone interface compared to the STS. It is concluded that the use of STS ensures tighter bony contact and enables higher pull-out strength; however, the use of NSTS improves the stiffness of the fixation and induces less damage to the cortical bone-screw fixation and thus minimum risk is obtained in terms of bone necrosis.