Dorsal Subaxial Cervical Instrumentation Techniques

Adaptations in cervical instrumentation techniques have provided a wide range of capabilities for spinal reconstruction. For instance, multiplanar and multisegmental instability are successfully treated with cervical fixation. Internal stabilization has the advantage of providing neural protection until fusion occurs, lessening the number of fused segments, facilitating immediate postoperative mobilization, and minimizing the need for external orthoses. Posterior cervical fixation techniques have been developed, and each has unique advantages and disadvantages.

This chapter discusses posterior cervical instrumentation techniques, including etiologies of subaxial cervical instability and operative techniques for instrumentation, with a particular emphasis on modern instrumentation techniques and emerging technologies. This chapter will also emphasize complication management and avoidance. Although biomechanical concerns are critical in the selection of the proper method of stabilization, they are discussed only briefly in this chapter and covered more extensively in the chapter on cervical construct planning.

Trauma

Posterior cervical instrumentation is commonly used in a trauma setting. The main goals in the management of cervical spine injuries are realignment, decompression of the neural elements, and stabilization. If the spine is adequately aligned, without the need for decompression, then external immobilization with a collar may be all that is required to protect the neural elements. Posterior cervical spine instrumentation should be considered in trauma patients who require an open reduction or a dorsal cervical decompression. Many patients can achieve long-term stabilization with fixation across the affected levels; however, it may be necessary to incorporate additional levels or a combined anterior-posterior approach, depending on the fracture pattern and extent of instability ( Fig. 107.1 ).

Tumor

The instability caused by tumor erosion of the bony elements, or secondary to decompressive techniques used in tumor resection, can be successfully managed with posterior cervical instrumentation. Depending on surgeon preference, some elect to pursue laminectomies with or without facet resection for tumor resection, with the plan for delayed instrumentation only in the setting of progressive deformity. Some surgeons argue that the absence of instrumentation allows a more straightforward evaluation of the tumor on postoperative magnetic resonance imaging (MRI) compared with hardware artifact that is seen on MRI after instrumentation. Other surgeons, including us, and other centers prefer to place instrumentation at the time of an index tumor resection. The number of motion segments to be instrumented depends on the location and extent of tumor involvement. Commonly, multilevel anterior corpectomy (>2 levels) and cage reconstruction for an anterior approach for tumor resection warrant posterior supplementation with hardware. Most spine surgeons recommend posterior subaxial instrumentation that bridges any anterior cage reconstruction for a three-level corpectomy or more ( Fig. 107.2 ).