Technologie implementace Kirschnerových drátů při zevní skeletální fixaci

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book

Czech

Tato práce se zabývá vývojem nového druhu K-drátu a jeho testováním v podmínkách laboratorních, klinických in vitro a in vivo pro použití v úrazové chirurgii, dětské ortopedii a an klinikách. Nejvyššího přínosu dosahuje při aplikaci v Ilizarově externé transoseální fixaci dlouhých kostí. Četné testy prokázaly mimořádně nízké zavádění síly a krouticí momenty potřebné pro inserci těchto K-drátů (35.23+-1.43 N, 0.064+-0.007 Nm, která je provázena nízkou inserční prací (32.6+-2.5) J, a nejnižším oteplením v místě zavádění(63+-3C). MKP analýza potvrdila vysokou odolnost tohoto K-drátu proti přetížení, což činí K-drát odolný a spolehlivý pro namáhání. Výsledky byly potvrzeny na řadě našich a zahraničních pracovišť.

This thesis deals with development of a new Kirschner wire (K-wire) design and its experimental testing in laboratory conditions and clinics for the use in orthopaedics, surgery, traumatology and clinics. The work contains general principles of Ilizarov external transosseous long bone fixation, bone drilling and pin implant insertion. Some mechanical engineering methods for the external skeletal implant insertion have been used, mainly based on insertion into polymethylmetacrylate, pig and goat bones (tibias). Numerous tests of the K-wire performance tested in vitro and in vivo are described. The novel type of K-wire can be characterised by its superior position and statistically significant (Scheffé multiple range test, confidence level 95%) lowest effort to insertion, expressed in terms of axial force (35.23+-1.43 N, torque moment 0.064+-0.007 Nm, work needed for its insertion 32.6+-.5 J, and the lowest elevation of temperature (63+-3C) measured in the place of insertion compared to the current types of K-wires (trocar, diamond) under the same cutting conditions. Two methods for drilling conditions optimising concluded in the lowest insertion energy for the lowest feeds and speeds, with no significant anomaly due to e.g. specific cutting force for drilling of such tissues. Scanning electron microscopy was used for morphology of drilled bone surfaces. Finite element analysis confirmed an excellent drilling performance and endurance of the new drilling tips as had been predicted on the base of tool life testing (more than 35 holes in a hard cortical bone). A study of threaded variants of K-wires to improve anchoring performance of the implant in the bone was included also. The range of pull-out forces reached the intervals 1 792+-341 (proximal part), 2 385+-200 (medial part) and 1 312+-322 (distal part) of pig tibia, but a reduction of 20 % of tensile strength due to thread cold rolling should be taken into consideration. No significant evidences have been found for cyclical dynamic loading of K-wire-bone interface, coursed by mechanical phenomena (stress, wear). Partially threaded olive K-wires were compared to a tension band wire fixation of cadaver human oleocran with encouraging results. A study of residual torque moments for K-wires and Orthofix screw pins when clinically extracting in the end of healing was done. The work integrates selected results of the new K-wire (Czech patent pending) achieved by the author in the Czech Republic and in the Great Britain, The University of Sheffield, Clinical Science Centre.

K wire, Ilizarov, fixation

PÍŠKA, M.

2002

1. 11. 2000

VUT IUM Brno

Brno

80-214-1948-2

Habilitační a inaugurační spisy, sv.62

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http://www.fme.vutbr.cz