Axis Screws: Surgical Results and Complications of a Large Case Series

Introduction: Spinal diseases such as trauma, congenital malformations, tumors and inflammatory disorders may lead to cervical instability involving the axis, requiring surgical fixation. Axis instrumentation using screws is a challenge but safe and efficient technique to stabilize this segment.

Objective: To present the surgical results of patients who underwent axis screw instrumentation, discussing surgical nuances and complications of the techniques used.

Methods: We performed a retrospective study of patients who underwent spinal surgery with axis instrumentation using pars, pedicle or laminar screws.

Results: Sixty-five patients with complete data were found in our database. Forty patients were male (61.5%), and twenty-five were female (38.5%). The average age was 42.2 years. The most common cause of mechanical instability was spinal cord trauma involving the axis (36 patients – 55.4%), followed by congenital craniocervical malformation (12 patients – 18.5%). Thirty-seven patients (57%) required concomitant C1 fusion. Bilateral axis fixation was performed in almost all cases. Twenty-three patients (35.4%) underwent bilateral laminar screws fixation; pars screws were used in twenty-two patients (33.8%) and pedicular screws were used isolated in only three patients (4.6%). In fourteen cases (21.5%), we performed a screw hybrid construction: lamina and pars (eight cases), pedicle and pars (three cases), pedicle and lamina (one case), bilateral pars and lamina (one case) and bilateral lamina and pars (one case). In three cases (4.6%), we had to use unilateral screw fixation: two with one laminar screw and one with pars screw. A total of 132 axis screws were used considering all the patients. There was no neurological worsening or complications directly related to the use of axis screws, such as vertebral artery injury. The most common complication was superficial wound infection in three cases (4.6%). One patient had a pars screw pull-out during follow-up, but was not reoperated once she had only mild cervical pain. One patient with a C2 pedicle screw had a canal violation but was not reoperated either, once the patient was asymptomatic.

Conclusion: Axis screw instrumentation is a safe and efficient method for cervical stabilization. Laminar and pars screws were the most commonly used techniques. The choice of the screw fixation technique must be based on the anatomical peculiarities of each patient and surgeon’s preference.