How Should We Grade Lumbar Disc Herniation and Nerve Root Compression? A Systematic Review

MRI is the gold standard for evaluating the relationship of disc material to soft tissue and neural structures. However, terminologies used to describe lumbar disc herniation and nerve root compression have always been a source of confusion. A clear understanding of lumbar disc terminology among clinicians, radiologists, and researchers is vital for patient care and future research. Through a systematic review of the literature, the purpose of this article is to describe lumbar disc terminology and comment on the reliability of various nomenclature systems and their application to clinical practice. PubMed was used for our literature search using the following MeSH headings: Magnetic Resonance Imaging and Intervertebral Disc Displacement and Lumbar Vertebrae and terms nomenclature or grading or classification. Ten papers evaluating lumbar disc herniation/nerve root compression using different grading criteria and providing information regarding intraobserver and interobserver agreement were identified. To date, the Combined Task Force (CTF) and van Rijn classification systems are the most reliable methods for describing lumbar disc herniation and nerve root compression, respectively. van Rijn dichotomized nerve roots from definitely no root compression, possibly no root compression, indeterminate root compression, possible root compression, and definite root compression into no root compression (first three categories) and root compression (last two categories). The CTF classification defines lumbar discs as normal, focal protrusion, broad-based protrusion, or extrusion. The CTF classification system excludes disc bulges, which is a source of confusion and disagreement among many practitioners. This potentially accounts for its improved reliability compared with other proposed nomenclature systems. The main issue in the management of patients with lumbar disc disease and nerve root compression is correlation of imaging findings with clinical presentation and symptomatology to guide treatment and intervention. Although it appears that the most commonly supported nomenclatures have strong interobserver reliability, the classification term disc bulges is a source of confusion and disagreement among many practitioners. Additional research should focus on the clinical application of the various nomenclatures.