Eficácia de três técnicas anestésicas na dor originada do casco em equinos

Abstract

The aim of the present study was to evaluate the effectiveness of the navicular bursa (NB), distal interphalangeal joint (DIJ) and deep digital flexor tendon sheath anesthesia (DDFTS) in horses with hoof pain. The effect of navicular bone and DIJ radiographic lesions on the block efficacy was also evaluated. Criterion of inclusion was a lameness improvement of 70% or higher until 15 minutes ( ) after palmar digital nerve (PDN) block. Based on that, fifteen horses with grade III forelimb lameness were selected. Blocks were performed separately in different trials with a minimum of 8-hour interval between each one. The first trial started with the PDN block, and the NB, DIJ and DDFTS anesthesia were conducted randomly among trials 2, 3 and 4. Moreover, the influence of exercise over lameness intensity was evaluated by trotting horses in a fifth trial without any block. The objective assessment of each trial was performed before, 5, 10, 15, 20, 30 and 60 after each block. The radiographic exam was performed at the NB trial. Horses were grouped according to degree of improvement, or by radiographic lesions, and an exact Fisher s test was used to compare frequencies with significance of p<0.05. NB and DIJ anesthesia presented similar effect at improvement rates of 50% or higher. However, NB was more effective in improve lameness above 70% at 10 (p=0.03). The highest improvement means for NB was at 5 (70.88%) and 10 (72.33%), and at 15 (58.76%) and 20 (56.17%) for DIJ anesthesia. The DDFTS block was less effective than NB and DIJ when evaluating lameness improvement above 50% or 70%. DIJ anesthesia was inferior to PDN block in ameliorate lameness more than 50 and 70% up to 20 minutes. The highest means of improvement for DDFTS block was at 5 (25.22%) and 10 (26.42%), and better responses were observed in horses with DDFT effusion. The exercise demonstrated low interference in reducing lameness since no improvement above 50% was observed, and additionally seven (46.66%) horses increased lameness intensity overtime. Navicular bone and DIJ lesions were observed in 40% of the horses, and in 53.33% horses had lesions identified only on the navicular bone. No difference on efficacy was observed when grouped horses according to radiographic lesions. NB and DIJ anesthesia showed improvement means above 50% until 30 . Objective assessment of hoof anesthesia technics demonstrated that NB and DIJ have similar efficacy in reducing hoof lameness and both technics were superior to the DDFTS block. The selection of hoof blocks order should be based on a thorough clinical examination, since it allows selection of pertinent blocks for each case. Moreover, hoof blocks should always start from the most to the least specific block and if possible carry them at different times.