Instrumented lumbar procedures are performed to augment fusion and provide stability, although the specific indications and added benefits of instrumentation are routinely debated. Historically, instrumentation of the spine began with wiring techniques by Hadra in 1891 (1) to stabilize a fracture-dislocation of the cervical spine. As knowledge of anatomy and biomechanics has improved, the concepts and designs of instrumentation have developed throughout the last century, for both anterior and posterior procedures, including hooks and rods, sublaminar wiring, transpedicular fixation, facet screws, interbody cages, anterior screws with plates or rods, as well as various combinations thereof. Techniques to implant such devices have also been modified or created, varying from traditional open to endoscopic approaches for anterior procedures, minimally invasive tube surgery and the Wiltse approach for posterior procedures and, recently, the introduction of surgical navigation systems to assist with placement of spinal instrumentation.

In order for patients to achieve the maximum benefit from any given surgical procedure, the surgeon must have a clear understanding of the indications and risks associated with the selected procedure. Minimizing risk is the foundation of the Hippocratic Oath, “First do no harm.” To do so, one must have a thorough understanding of the relevant anatomy, the procedure itself, and the risks and benefits associated with the use of instrumentation and its alternatives, and then one must apply this knowledge to the correctly selected patient.

The role of instrumentation in lumbar procedures remains somewhat controversial with certain lumbar pathologies. Of the recent prospective randomized trials, conflicting conclusions have been made regarding instrumented versus noninstrumented fusions in the lumbar and lumbosacral spine. Fischgrund et al. (2) reported successful fusion rates of 82% and 45% in instrumented versus noninstrumented degenerative lumbar spondylolisthesis with spinal stenosis, respectively. In a prospective, randomized trial, Zdeblick (3) reported arthrodesis in 65% of noninstrumented, 77% of semirigid, and 95% of rigidly instrumented cases. Conversely, Thomsen et al. (4) found no significant difference in both outcomes and fusion rates in instrumented and noninstrumented fusions with arthrodesis achieved in 68% and 85%, respectively.

Thorough, critical review of the literature is necessary to draw any significant, applicable conclusions regarding the effects of surgical treatment and outcomes. Bono and Lee (5) performed a critical analysis of trends in fusion for degenerative disc disease, concluding that greater use of technology has been noted in the literature and trends toward increased fusion rates; however, the clinical and functional benefits are not yet clear. The authors also point to multiple weaknesses in the spinal literature, with articles lacking information such as the type of instrumentation used, graft location, fusion rate, graft source and brace type, or simply failing to state clearly the study methodology. As such, reviewing and comparing outcomes (which are also quite variable) between studies is limited.

Regardless of these recognized weaknesses in determining
the optimum surgical indications for instrumentation, its role still exists, and the surgeon must recognize potential complications when using instrumentation to augment fusion. The goal of this chapter is to cover the incidence of complications related to lumbar pedicle instrumentation, the relevant anatomy, and how to prevent and manage these complications when they occur.