Konik ve silindirik pedikül vidalarının sıyırma dirençleri ve direngenliklerinin karşılaştırmalı biyomekanik analizi

Yıl 2019, Cilt: 12 Sayı: 3, 367 - 377, 31.12.2019

Ömer Polat , Ali Rıza Gezici Özhan Merzuk Uçkun , Osman Arıkan Nacar

https://doi.org/10.26559/mersinsbd.605225

Öz

Amaç: Transpediküler enstrümantasyonda konik
ve silindirik pedikül vidaları sık kullanılmaktadır. Vidaların mekanik
performansı kemik-vida yüzeyinin biyomekanik özellikleri ve vidanın fiziksel
yapısı ile ilişkilidir. Bu çalışmada, konik ve silindirik pedikül vidalarının
biyomekanik açıdan farklarının olup olmadığının araştırılması amaçlandı. Yöntem: İskelet maturasyonunu
tamamlamış, 400-600 kg ağırlığında 24–32 haftalık danalardan elde edilmiş taze lomber
vertebralar kullanıldı. Toplam 24
vertebranın her iki pedikülüne (48 pedikül) vida yerleştirilerek biyomekanik
testler uygulandı. Vidaların maksimum giriş tork değerleri analog tork metre kullanılarak
kaydedildi. Rijid
tespitin sağlanması için polimetilmetakrilat içeren metal kutuların içerisine
gömülü vertebradaki pedikül vidaları mekanik test makinasına bağlanarak sıyırma
direnci ölçüldü. Bulgular: Konik
vidaların sıyırma dirençlerinin ve direngenliklerinin ilk atım ve tekrarlayan
atımlarda silindirik vidalara göre yüksek olduğu, ancak aradaki farkın
istatistiksel olarak anlamlı olmadığı tespit edildi (p>0.05). Maksimum giriş
tork değeri ise konik vidalarda silindirik vidalara göre istatistiksel olarak
anlamlı düzeyde yüksek idi (p=0.04). Vidaların 180º ve 360°geri çekimli sıyırma
direnci ve direngenlik verileri arasında istatistiksel olarak anlamlı fark
olmadığı tespit edildi (p>0.05). Sonuç:
Konik vidaların silindirik vidalara göre daha dirençli tutunma verilerine
sahip olmalarının yanı sıra, aynı delikten yapılan çoklu vida atımlarında ya da
geri çekilme işlemi sonucunda vidalar arasında sıyrılma verileri açısından
belirgin bir fark izlenmemiş olması, konik vidaların gelecekte daha sık
kullanılacaklarını düşündürmektedir. 

Anahtar Kelimeler

Transpediküler fiksasyon, Konik vida, Silindirik vida, Biyomekanin analiz

A comparative biomechanical analysis of pull-out resistance and stiffness of conical and cylindrical pedicle screws

Öz

Aim:
Conical and cylindrical pedicle screws are frequently used
in transpedicular instrumentation. The mechanical performance of screws is
associated with the biomechanical properties of the bone–screw surface and the
physical structure of the screw. The purpose of this study was to investigate
whether conical and cylindrical pedicle screws differ in their biomechanical
properties. Methods: Fresh lumbar
vertebrae were obtained from 24–32-week-old calves that completed skeletal
maturation and weighed 400–600 kg. Screws were placed on both pedicles (48
pedicles) of total 24 vertebrae, and biomechanical tests were performed. The
maximum input torque values of the screws were recorded using an analog torque
meter. Pull-out resistance was measured by attaching pedicle screws in the
vertebra. The vertebral pedicle screws were embedded into metal boxes
containing polymethyl-methacrylate to provide rigid fixation to a mechanical
tester. Results: Pull-out resistance
and stiffness were higher in conical screws than in cylindrical screws in the
first and repetitive insertions; however, the difference was not statistically
significant (p>0.05). The maximum input torque was significantly higher
(p=0.04) in conical screws than in cylindrical screws. No significant
difference (p>0.05) was observed between pull-out resistance and stiffness
values of the screws with 180° and 360° back-outs. Conclusion: Conical screws had more resistant fixation data than
cylindrical screws, and there was no significant difference between the screws
in terms of pull-out resistance data due to multiple screw insertions performed
from the same hole or due to the back-out procedure; this indicates that
conical screws are likely be used more frequently in the future.

Anahtar Kelimeler

Transpedicular fixation, conical screw, cylindrical screw, biomechanical analysis

Kaynakça

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