The Influence of Thread Tap Mismatch on Pedicle Screw Pullout Strength

• Autor(a) principal: Pinheiro,Rômulo Pedroza
• Data de Publicação: 2022
• Outros Autores: Miranda,Raffaello de Freitas, Shimano,Antonio Carlos, Chandanson,Thibault, George,Keri, Defino,Helton L.A.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Brasileira de Ortopedia (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0102-36162022000200327
• topic: spinal fusion; pedicle screw; bone screws; biomechanical phenomena/ physiology

Abstract Objective We aimed to study the “in vitro” pullout strength of SpineGuard/Zavation Dynamic Surgical Guidance Z-Direct Screw (DSG Screw, SpineGuard Inc, Boulder, Colorado, USA), a screw designed to be inserted using a direct insertion technique. Methods Dynamic Surgical Guidance Screws of 5.5 and 6.5 mm were introduced into polyurethane blocks with a density of 10 PCF (0,16g/cm3). According to the experimental group, screws were inserted without pilot hole, with pilot without tapping, undertapping and line-to-line tapping. Screw pullout tests were performed using a universal test machine after screw insertion into polyurethane blocks. Results Screws inserted directly into the polyurethane blocks without pilot hole and tapping showed a statistically higher pullout strength. Insertion of the screw without tapping or with undertapping increases the pullout screw strength compared with lineto-line tapping. Conclusion Dynamic Surgical Guidance Screw showed the highest pullout strength after its insertion without pilot hole and tapping.