Diagnostic nerve blocks in the management of low back pain secondary to facet joint syndrome. / Bloqueos diagnósticos en el manejo del paciente con lumbalgia secundaria a síndrome facetario.

Low back pain is currently one of the main public health problems. Among the multiple causes, pain in the zygapophysial joints, also called facets or posterior vertebral joints, are an important cause, usually secondary to osteoarthritis. The source of low back pain is often difficult to find, making the therapeutic approach to the patient sub-optimal. Diagnostic blocks are a very important tool in establishing an adequate treatment for patients with low back pain, as long as they are performed accurately, with an adequate local anaesthetic volume, with a suitable image and fluoroscopic projection and its result are precisely interpreted. In this article a review is presented on the importance of diagnostic blocks, as well as how they should be performed in order to obtain the maximum information and the greatest therapeutic benefit.

Validity and reliability of the Spanish-language version of the self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) pain scale. / Validación y fiabilidad de la versión española de la escala autoadministrada de Evaluación de Signos y Síntomas Neuropáticos de Leeds (S-LANSS).

INTRODUCTION: The self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) scale is a tool designed to identify patients with pain with neuropathic features. OBJECTIVE: To assess the validity and reliability of the Spanish-language version of the S-LANSS scale. METHODS: Our study included a total of 182 patients with chronic pain to assess the convergent and discriminant validity of the S-LANSS; the sample was increased to 321 patients to evaluate construct validity and reliability. The validated Spanish-language version of the ID-Pain questionnaire was used as the criterion variable. All participants completed the ID-Pain, the S-LANSS, and the Numerical Rating Scale for pain. Discriminant validity was evaluated by analysing sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC). Construct validity was assessed with factor analysis and by comparing the odds ratio of each S-LANSS item to the total score. Convergent validity and reliability were evaluated with Pearson's r and Cronbach's alpha, respectively. RESULTS: The optimal cut-off point for S-LANSS was ≥12 points (AUC=.89; sensitivity=88.7; specificity=76.6). Factor analysis yielded one factor; furthermore, all items contributed significantly to the positive total score on the S-LANSS (P<.05). The S-LANSS showed a significant correlation with ID-Pain (r=.734, α=.71). CONCLUSION: The Spanish-language version of the S-LANSS is valid and reliable for identifying patients with chronic pain with neuropathic features.