Lateral mass lesions of the C1 vertebra: a modified "far lateral" approach.

Purpose: The surgical removal of lateral mass lesions is demanding due to their close anatomical relationship with the vertebral artery, upper spinal cord as well as overlying muscular structures. Usually a dorsal approach will be performed to reach the lateral mass. The disadvantage of this approach is the extensive mobilization of the neck muscles required to allow exposure of the lateral mass, which can be accompanied by severe muscular atrophy due to the damage of the local innervation. Additionally, management of the exposure of the vertebral artery is hindered by the dorsal approach.

Methods: A modified "far lateral" approach with complete resection of the lateral mass of C1 followed by a substitute with a Harms cage is presented.

Results: A 54-year-old woman was suffering from severe neck pain accompanied by a progressive sliding of her head and the visual axis to the right hand side. MRI as well as CT scans showed an osteolytic destruction of the right lateral mass of C1. After occipito-cervical fusion the osteolytic lateral mass was removed using a far lateral approach to the upper cervical spine. The patient recovered immediately after surgery, the neck pain improved and the lateral bending of the head was balanced.

Conclusions: This far lateral approach offers the advantage of direct visualization of the lateral aspect of the upper cervical spine with the opportunity for local stabilization at the center of rotation.