Pain Drawing in the Assessment of Nerve Root Compression in the Degenerative Spondylosis

Study Design: A retrospective study. Objectives: To explore the pattern of pain distribution in HNP and spinal stenosis with or without degenerative spondylolisthesis (DS), and to evaluate the diagnostic value of pain drawings in predicting the presence of a painful nerve root. Summary of Literature Review: The usefulness of pain drawing as a tool to predict the presence of painful nerve root compression is unclear. Materials and Methods: Fifty-seven patients (27 HNP, 21 pure spinal stenosis, and 9 spinal stenosis with DS) with leg pain were recruited. The presence of painful nerve root compression was judged based on MRI and clinical findings. Each grid of the pain drawing is assigned an area code, and discriminant analysis was performed to explore indications of painful nerve root. Diagnostic values were evaluated by calculating sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results: Pain distribution was characterized by a dermatomal pattern in HNP and variable in the spinal stenosis group. Paresthesia on the sole was extracted as a discriminant factor indicating painful compression of the S1 nerve root. In HNP, the sensitivity, specificity, PPV, and NPV of this factor were 62%, 100%, 100%, and 74% respectively. In the spinal stenosis group, they were 80%, 56%, 27%, and 93%, respectively. Conclusions: The pain drawing can help assess painful nerve root compression as well as confirm the pattern of pain distribution.