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Related Experiment Video

Updated: May 23, 2026

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

Published on: May 31, 2017

Biomechanical analysis of second-generation headless compression screws.

Soroush Assari¹, Kurosh Darvish, Asif M Ilyas

¹Department of Mechanical Engineering, Temple University, Philadelphia, PA 19122, USA.

|April 10, 2012

Summary

Second-generation headless compression screws (SG-HCS) offer improved biomechanical performance over first-generation designs. The Mini-Acutrak 2 screw demonstrated superior compression force and reliability in osteoporotic bone models.

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Last Updated: May 23, 2026

An Anesthesia, Surgery, and Harvest Method for the Evaluation of Transpedicular Screws Using an In Vivo Porcine Lumbar Spine Model

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Minimally Invasive Treatment for Thoracolumbar Burst Fracture Using Sagittal Alignment Screws and A Trauma Reduction Device

Minimally Invasive Treatment for Thoracolumbar Burst Fracture Using Sagittal Alignment Screws and A Trauma Reduction Device

Published on: November 8, 2024

Area of Science:

Orthopedic biomechanics
Biomaterials and implant design
Surgical fixation techniques

Background:

Headless compression screws (HCS) are standard for small bone and articular fracture fixation.
Newer second-generation HCS (SG-HCS) aim for enhanced biomechanical properties.
Comparative analysis of SG-HCS biomechanical efficiency is needed.

Purpose of the Study:

To compare the biomechanical efficiencies of various SG-HCS.
To evaluate the performance of first-generation versus second-generation HCS.

Main Methods:

Five HCS types were tested: four SG-HCS (Mini-Acutrak 2, Twinfix, Kompressor Mini, HCS 3.0) and one first-generation (Herbert-Whipple).
Tests were conducted on polyurethane foam blocks simulating osteoporotic bone with a transverse fracture.
Compression force and fastening torque were measured during insertion, with and without pre-drilling.

Main Results:

Mini-Acutrak 2 generated the highest compression force (45.41 ± 0.88 N); Herbert-Whipple generated the lowest (13.44 ± 2.35 N).
SG-HCS showed a slight, non-significant increase in compression force without pre-drilling, but a significant increase in fastening torque.
Over-fastening significantly reduced compression force in Twinfix and Kompressor screws, highlighting potential misleading torque measurements.

Conclusions:

All SG-HCS outperformed the first-generation Herbert-Whipple screw in biomechanical characteristics.
Mini-Acutrak 2 exhibited maximum compression, reliability, and sustainability due to its variable pitch design.
Independently rotating trailing head screws (Twinfix, Kompressor Mini) showed compression loss with over-fastening; fastening torque can be an unreliable indicator of compression.