The Accuracy and Safety of Free-Hand C7 Laminar Screw Fixation: A Clinical Study of 43 Consecutive Patients.

Abstract

Study design: Retrospective case series.

Background: C7 laminar screw is a feasible substitute for C7 pedicle screw with the potential to decrease neurovascular complications and minimize the requirement for intraoperative fluoroscopic guidance. Nevertheless, the clinical evidence regarding their accuracy and safety is still limited.

Objective: To evaluate the accuracy and safety of free-hand placement of C7 laminar screw in a series of consecutive patients.

Methods: This study included 43 patients who underwent posterior cervical fixation with C7 laminar screw using a free-hand technique. A total of 61 C7 laminar screws and their direction and degree of laminar cortical violation were evaluated for their accuracy and safety by postoperative computed tomography scan. Neurovascular complications were also evaluated.

Results: Out of the 61 screws, 14 (23%) penetrated the laminar cortical wall, with 3 dorsal and 11 ventral breaches. Of those 14 screws, 11 screws (18%) experienced a breach of <50% of screw diameter, whereas 3 screws (5%) fell between 50% and 100% breach. No screws resulted in complete cortical violation. There were no instances of neurovascular complications. There was no mechanical complication requiring revision surgery.

Conclusions: Free-hand C7 laminar screw fixation demonstrated acceptable accuracy and safety. Despite a frequent occurrence of laminar cortical breach (25%) with our free-hand technique, there was no clinically relevant neurovascular or mechanical complications occurred. This technique may offer a feasible option for C7 posterior fixation alternative to pedicle screw, especially in situations where advanced imaging guide is unavailable.