Avaliação do bloqueio do músculo quadrado lombar no manejo da dor miofascial em pacientes com lombalgia crônica

Abstract

Low back pain is a frequent reason for visits to healthcare services, generating significant costs. It is suggested that up to 80% of chronic low back pain (CLBP) cases involve myofascial pain syndrome (MPS), which is often underdiagnosed. The quadratus lumborum muscle (QLM) block appears to have an important effect in relieving CLBP with both MPS-related and nonspecific components. The objective was to evaluate the effectiveness of a simple quadratus lumborum block with ropivacaine in reducing pain in patients with CLBP, as well as its impact on patients' functionality and quality of life. This was a randomized, double-blind, concealed allocation clinical trial conducted at the pain clinic of Walter Cantídio University Hospital – UFC (HUWC) from August 2024 to December 2024. Thirty patients were evaluated, divided into 2 groups of 15 patients each, undergoing a type 3 QLM block using 2% ropivacaine guided by ultrasound (anesthetic group - AG) and 0.9% saline solution (saline group - SG), with a 30-day washout period, crossover, and reevaluation 30 days after the new intervention. Primary outcome: pain (measured by the Brief Pain Inventory - BPI). Secondary outcomes: functionality (measured by WHODAS), anxiety and depression (assessed by the Beck Inventories for anxiety and depression). There was an improvement in pain, with a reduction in all BPI scores (AG 5.27 ± 3.51 vs SG 8.63 ± 1.97, p=0.033), as well as in anxiety and depressive symptoms, and improved functionality across several WHODAS 2.0 categories, especially in mobility (AG 30 ± 26 vs SG 61 ± 16, p=0.005). It is concluded that the QLM block has significant potential in the treatment of CLBP with an MPS component, standing out as an outpatient procedure with positive effects on pain, functionality, sleep, anxiety, and depression scores.