The Attallah screw: Where safety meets robustness in posterior subaxial cervical instrumentation

TL;DR

The study compares the Attallah screw with lateral mass and pedicle screws for cervical spine fixation, focusing on insertion torque and safety.

Contribution

The Attallah screw is introduced as a novel fixation method combining the safety of lateral mass screws with the strength of pedicle screws.

Findings

Attallah screws showed similar peak insertion torque to pedicle screws at C3, C4, and C7, but not at C5 and C6.

Pedicle screws had higher peak insertion torque than lateral mass screws from C4 to C7.

Attallah screws outperformed lateral mass screws only at C7 in terms of insertion torque.

Abstract

Posterior fixation of the subaxial cervical spine (SCS) commonly relies on the application of lateral mass screws (LMS), with pedicle screws being a less prevalent alternative. The present study provides another option: A recently introduced novel approach, the Attallah screw, intended to ensure a safety profile comparable to that of LMS, combined with a strength profile similar to that of pedicle screws. The focus of the present study is the comparative analysis of peak insertion torques for these three screw types. Employing standard surgical techniques and instruments, Attallah screws were scheduled for insertion on the right side of the SCS in 15 cadavers, pedicle screws on the left side in 8 cadavers, and LMS on the left side in the remaining 7 cadavers. The peak insertion torque was recorded using an electronic torque screwdriver. The results revealed that the peak insertion torques were similar in the pedicle and the Attallah screw at C3, C4 and C7, but differed at C5 (mean ± SD; pedicle, 79.5±19.6 cNm; Attallah, 56.7±18.5 cNm; P=0.029) and C6 (pedicle, 85.4±28.7 cNm; Attallah, 49.8±17.9 cNm; P=0.004) in favor of the superior pedicle screw measurements. The peak insertion torques of the pedicle screw were superior to the corresponding data from the LMS from C4 to C7. By contrast, the peak insertion torques of the Attallah screw were only superior to those of the LMS at C7 (Attallah, 69.5±24.5 cNm; lateral mass, 40.5±21.4 cNm; P=0.030), although similar trends were observed at the other cervical levels. On the whole, the findings presented herein indicate the level-dependent superior robustness of the Attallah screw as a posterior cervical fixation method compared to the LMS. However, from a biomechanical perspective, the pedicle screw remains the preeminent choice for fixation within the C5-C6 range.

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