Degenerative lumbar spinal stenosis: current strategies in diagnosis and treatment

Abstract

Introduction: Although the aging of the population is causing a dramatic rise in the incidence of lumbar spinal stenosis, the indications and options for surgical treatment are not clearly defined.

Methods: In an attempt to aid clinical decision making, a selective literature review was conducted, taking into account the guidelines of the Association of the Scientific Medical Societies in Germany (AWMF).

Results: In degenerative lumbar spinal stenosis hypertrophy of the facet joints and yellow ligaments brings about constriction of the spinal canal, leading to back pain and activity-dependent lower limb symptoms (neurogenic claudication). If conservative treatment fails, an imaging study, usually magnetic resonance imaging, is required. In the case of severe symptoms the progressive underlying degeneration necessitates surgical treatment. Minimally invasive fenestration techniques are usually employed to decompress the spinal canal; in the presence of instability, fusion is indicated.

Discussion: Despite the proven superiority of surgery in the management of refractory lumbar spinal stenosis, there is a lack of evidence-based data regarding the different surgical treatment options. The evaluation of modern, minimally invasive techniques is thus difficult.

Keywords: fenestration; fusion; laminectomy; lumbar spinal stenosis; neurogenic claudication; surgery.

Figure 1

Schematic axial representation of the degenerative changes to the lumbar spine. Narrowing of the spinal canal (red) develops subsequent to disk protrusion (blue), hypertrophy of the facet joints (gray), and hypertrophy or folding in of the ligamentum flavum (yellow). Depending on the location of the changes, the lateral recess and/or neuroforamina may also undergo narrowing (orange). Lumbar olisthesis or instability can also result in a narrowing of the spinal canal and especially the neuroforamina.

Figure 2

Algorithm for the treatment of lumbar spinal stenosis (adapted from [3]). NSAIDs, non-steroidal anti-inflammatory drugs

Figure 3

Postmyelographic computed tomography scan before (a) and immediately after decompressing lumbar spinal stenosis by means of laminectomy (b), bilateral fenestration (c), and unilateral fenestration with undercutting contralateral decompression (d). The decompression techniques are illustrated with corresponding schematic representations of access (green). Laminectomy of the spinal canal decompresses a longer section of the spine, whereas fenestration techniques are limited to the level of the intervertebral space and the hypertrophied facet joints.

Figure 4

Algorithm for additional stabilization in the subgroup of patients with lumbar spinal stenosis and complicating factors in the sense of instability (TLIF/PLIF: transforaminal/posterior lumbar interbody fusion). An orientation aid is given with regard to the selection of the stabilization procedure on the basis of different individual variables. In the authors’ experience, most patients follow the highlighted treatment pathway.