C1 lateral mass screws for posterior segmental stabilization of the upper cervical spine and a new method of three-point rigid fixation of the C1-C2 complex

Abstract

-Objective: To describe our experience with C1 lateral mass screws as part of a construct for C1-2 stabilization and report an alternate method of C1-C2 complex three-point fixation. Method: All patients that had at least one screw placed in the lateral mass of C1 as part of a construct for stabilization of the C1-C2 complex entered this study. In selected patients who had a higher chance of nonunion an alternate construct was used: transarticular C1-C2 screws combined with C1 lateral mass screws. Results: Twentyone C1 lateral mass screws were placed in 11 patients. In three patients the alternate construct was used. All patients had a demonstrable solid and stable fusion on follow-up. Conclusion: C1 lateral mass screws are safe and provide immediate stability. The use of C1-C2 transarticular screws combined with C1 lateral mass screws is a feasible and also an excellent alternative for a three-point fixation of the C1-C2 complex.KEY WORDS: C1 lateral mass, C1 lateral mass screws, C1-C2 instability, C1-C2 transarticular screws, atlantoaxial stabilization, cervical spine instrumentation. Parafusos na massa lateral de C1 para instrumentação segmentar da coluna cervical alta e um novo método de fixação em três pontos do complexo C1-C2RESUMO -Objetivo: Descrever nossa experiência com o uso de parafusos na massa lateral de C1 como parte de uma montagem para estabilização do complexo C1-C2 e relatar uma fixação alternativa em três pontos do complexo C1-C2. Método: Todos os pacientes em que pelo menos um parafuso na massa lateral de C1 foi colocado como parte de uma montagem para estabilização C1-C2 entraram neste estudo. Em certos pacientes com maior chance de não-união, uma montagem alternativa foi usada: parafusos transarticulares C1-C2 associados a parafusos na massa lateral de C1. Resultados: Foram colocados 21 parafusos na massa lateral de C1 em 11 pacientes e em três pacientes foi usada a montagem alternativa. Todos os pacientes evoluíram para uma união sólida e estável. Conclusão: Parafusos na massa lateral de C1 são seguros e conferem estabilidade imediata. Parafusos na massa lateral de C1 combinados a parafusos transarticulares são exequíveis e também excelente alternativa para fixação rígida em três pontos do complexo C1-C2. PALAVRAS-CHAVE: massa lateral de C1, parafusos na massa lateral de C1, instabilidade C1-C2, parafusos transarticulares C1-C2, estabilização atlantoaxial, instrumentação da coluna cervical.Atlantoaxial instability can be caused by trauma, infection, tumors, arthritis, congenital anomalies, iatrogenic (odontoidectomy) or other less common conditions. Most commonly instability at the C1-C2 complex requires internal fixation not only for immediate stability but also to provide long-term immobility so as to attain a solid fusion. Wiring techniques such as the Gallie, Brooks and modified Brooks are known to provide less than optimal immobilization of the C1-C2 complex not only for axial rotation but also for lateral bending and flexion-extension 1,2 . Newer internal fixation technique...

C2 Nerve Root Sectioning in Posterior Atlantoaxial Instrumented Fusions: A Structured Review of Literature

“…Case reports were excluded and a given series had to report on at least 10 patients to be included. Articles that included posterior cervical instrumentation and fusion at subaxial or occipital levels were included only if the data on patients undergoing C1-2 fusions were separated or those studies specifically describing the consequences of C2 nerve section or preservation for the insertion of C1 lateral mass screws (4,12,32,47). The data from these four studies were used only for the dependent variable outcomes of vertebral artery injury from C1 screw insertion, screw malpositioning, and C2 nerve outcomes.…”

Morphometric Study of Axis Vertebra in Subjects of Indian Origin

“…[12] Instability at the atlas and axis requires internal fixation not only for immediate stability, but also to provide long-term immobility so as to attain a solid fusion. [13] There are a wide variety of surgical techniques to achieve this, including anterior odontoid screw fixation or posterior fusion methods such as Gallie-type fusion, BrookeJenkins technique, interlaminar clamps or Sonntag's modified Gallie fusion. [14] Previously wiring methods like sublaminar, spinous process, tension band, facet and triple wiring were done.…”

Undetected Vertebral Artery Groove and Foramen Violations During C1 Lateral Mass and C2 Pedicle Screw Placement

“…To date, 3 studies [13][14][15] have assessed the accuracy of C1 and C2 screw insertion, using postoperative CT scans. Stulik et al 13 reported in a retrospective study that all 56 C1 lateral mass screws (100%) were positioned correctly and only 3 of 56 screws (5.4%) placed into C2 were malpositioned.…”