An alternative way of C1 screwing: Supralaminar C1 lateral mass screws

This study involves literature review, technical note, and case series.

The objectives were to analyze indications and contraindications, advantages, and disadvantages for C1 lateral mass screw (LMS) insertion above or partially above the arch, to descript technical features, and to give examples of the practical application of this technique and investigated its safety.

A literature review was carried out in English and Russian in PubMed, Google Scholar, and eLibrary databases. We selected four patients, treated in our clinic, which was carried out partially supralaminar C1 LMS.

Only three descriptions of supralaminar C1 LMS were found in the literature. Four adult patients underwent posterior C1-C2 screw fixation with C1 LMS along the superior edge of the C1 arch at our clinic. Partially supralaminar C1 screws were inserted on one of the sides due to the difficulties of using classical techniques. The main reasons for supralaminar screw fixation were narrow C1 lamina, hypertrophied venous plexus, and intraoperative failures of classic techniques application (broken screw trajectory, profuse venous bleeding from the plexus). The average follow-up time for the patients was 2.7 years, no complications were noted, and all had a satisfactory spinal fusion.

The proposed types of C1 LMS above or partially above the C1 arch can be useful alternative method of C1 screwing in selected patients. Indications for the use of the supralaminar C1 LMS method can be narrow C1 posterior arch and pedicle, pronounced C1-C2 venous plexus, some V3 segment anomalies at C1 level, small arthritic inferior part of lateral mass, and intraoperative failures of classic techniques application.