Viskoelastik Malzemeli Kemik-plak Sisteminin Performans Açısından Değerlendirilmesi

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2008Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2008Bu çalışmada, prototipi üretilmiş viskoelastik malzemeli kemik plağı, sonlu elemanlar yöntemi kullanılarak performansı açısından değerlendirilmiştir. Bu amaçla, viskoelastik malzemeli, Ti alaşımlı ve paslanmaz çelikten (316L) imal edilmiş kemik plaklarının uzun tibia kemiğine vidalarla bağlanmış üç boyutlu sonlu elemanlar modeli ANSYS programı kullanılarak oluşturulmuş ve aynı yükleme ve sınır koşulları altında gerilme analizleri yapılmıştır. İyileşmenin olmadığı durum için plakların orta kesitlerinde meydana gelen maksimum çekme ve basma gerilmeleri teorik olarak hesaplanmıştır. Elde edilen sonuçların nümerik sonuçlarla uyuştuğu görülmüştür. Kemiğin iyileşmesi sürecinde kırık ara yüzeyinde meydana gelen gerilmeler üç farklı kemik-plak sistemi içinde incelenmiş, elde edilen sonuçlar grafiksel olarak gösterilerek karşılaştırılmıştır. Viskoelastik malzemeli kemik plağının, paslanmaz çelik ve Ti alaşımlı kemik plağına kıyasla kırık ara bölgesinde gerilme kalkanını azaltarak iyileşmeyi hızlandıracak daha büyük basma gerilmeleri meydana getirdiği tespit edilmiştir.In this study, the bone plate with viscoelastic material, prototype of which was made, was evaluated in terms of its performance. For this reason, 3D finite element models of the bone plate with viscoelastic material and traditional bone plates, made of stainless steel (316L) and Ti alloy, have been developed by using ANSYS program and their stress analyses have been carried out under the same loading and boundary conditions. Maximum compressive and tensile stresses occurring in the middle sections of the bone plates in the beginning (there is no callus formation) have been calculated theoretically. These values have been compared with analysis results so that it could be verified that the results of numerical study were reasonable. Compressive stresses occurring in the intact portion of the bone (tibia) and at the fractured interface at the different stage of bone-healing have been investigated for all the three types of fixation. The results obtained have been compared and shown in graphs. It has been determined that the bone plate with viscoelastic material offers less stress-shielding to the bone, providing higher compressive stress at the fractured interface to induce accelerated healing in comparison with Ti alloy and stainless steel bone plate

Transmural migration of a surgical compress into the stomach after splenectomy: a case report

A surgical compress retained in the abdominal cavity following surgery is a serious problem. Here, we describe a 33-year-old female who was admitted with abdominal pain, vomiting, no passage of gas or feces, and abdominal distension for 3 days. She had a splenectomy at another medical center 4 years previously. An upright plain abdominal film revealed small bowel obstruction with marked small bowel air-fluid levels. The physical examination revealed muscular guarding and rebound tenderness in the periumbilical region. Therefore, a laparotomy was performed. A surgical compress was removed at enterotomy and the final diagnosis was gossypiboma. Because a retained surgical compress may lead to medicolegal problems, it is important to count the material used before and after a surgical procedure to reduce the risk of this problem