Interventional analgesic block in a dog with cauda equina syndrome. Case report / Bloqueio analgésico intervencionista em cão com síndrome da cauda equina. Relato de caso

ABSTRACT BACKGROUND AND OBJECTIVES: The cauda equina syndrome is a neurological condition prevalent in dogs which neurological signs are caused by the compression of the nerve roots located in the lumbosacral spinal canal and is frequently associated with pain, claudication, paresis or paralysis of the hindlimbs and changes in the functioning of the sphincters. The objective of this study was to check the effects of the epidural injection with the combination of dexamethasone, bupivacaine and morphine on the relief of pain and neurological signs in a dog with traumatic cauda equina syndrome. CASE REPORT: Case study of a 2-year old Red Heeler dog, weighing 16kg with a diagnosis of post-trauma cauda equina syndrome. The evaluation consisted of neurological and pain assessment (visual analog scale), quality of life ("5H2M") and infrared thermography. After the initial evaluation and authorization of the tutor, the dog was submitted to general anesthesia and a lumbosacral epidural block, guided by electrostimulation, with the association of dexamethasone, bupivacaine and morphine. After the procedure, the dog showed immediate remission of claudication, paresis and satisfactory analgesia on days 0, 15, 30 and 60 after the intervention. CONCLUSION: The epidural block was effective in improving pain, quality of life and neurological signs and may be an excellent alternative in dogs with pain syndromes associated with the spinal canal.

RESUMO JUSTIFICATIVA E OBJETIVOS: A síndrome da cauda equina é uma afecção neurológica prevalente em cães cujos sinais neurológicos são causados pela compressão de raízes nervosas localizadas no canal espinhal lombossacral sendo frequentemente associada à dor, claudicação, paresia ou paralisia de membros pélvicos e alterações do funcionamento dos esfíncteres. O objetivo deste estudo foi verificar os efeitos da injeção peridural com a associação de dexametasona, bupivacaína e morfina no alívio da dor e dos sinais neurológicos em um cão com síndrome da cauda equina de origem traumática. RELATO DO CASO: Estudo do caso de um animal da espécie canis familiaris, raça red heeler, fêmea, 2 anos de idade e 16kg de peso corporal com diagnóstico de síndrome da cauda equina pós-trauma. A avaliação consistiu no exame neurológico completo, avaliação de dor (escala analógica visual), de qualidade de vida ("5H2M") e por termografia infravermelha. Após a avaliação inicial e autorização do tutor, a cadela foi submetida à anestesia geral e a um bloqueio intervencionista peridural lombossacral, guiado por eletroestimulação, com a associação de dexametasona, bupivacaína e morfina. Após o procedimento, a cadela apresentou imediata remissão da claudicação, da paresia e uma satisfatória analgesia nos dias 0, 15, 30 e 60 após a intervenção. CONCLUSÃO: O bloqueio peridural intervencionista foi eficaz na melhora da dor, da qualidade de vida e dos sinais neurológicos, podendo ser uma excelente alternativa em cães com síndromes dolorosas associadas ao canal espinhal.

Ultrasound and gross anatomy of the brachial plexus and major nerves of the forelimb. An anesthetic approach using the domestic rabbit (Oyctolagus cuniculus) as an experimental model1

PURPOSE: To update the gross and sonographic anatomy and propose landmarks to perform ultrasound-guided (US-guided) axillary brachial plexus block (BPB) in rabbits. METHODS: Forty New Zeeland's rabbit (NZR) cadavers were dissected and the nerves were trimmed, identified, measured, and photographed. Additionally, in twenty NZRs, sonographic images of brachial plexus (BP) were performed through a simple-resolution ultrasound device. The US-guided block was achieved through a minimum volume of lidocaine necessary to surround the BP roots. The effectiveness of the brachial plexus block was assessed on sensitivity and motor functions. RESULTS: The BP resulted from connections between the ventral branches of the last four cervical spinal nerves and the first thoracic spinal nerve. In the axillary sonoanatomy, the BP appeared as an agglomerate of small, round hypoechoic structures surrounded by a thin hyperechoic ring. The amount of time and the minimum volume required to perform was 4.3 ± 2.3 min and 0.8 ± 0.3ml, respectively. CONCLUSIONS: The gross and sonographic anatomy of the BP showed uncommon morphological variations. Moreover, from sonographic landmarks, we showed complete reproducibility of the axillary US-guided brachial plexus block with simple resolution equipment and small volume of anesthetics required.

Pain assessment in cats undergoing ovariohysterectomy by midline or lateral celiotomy through use of a previously validated multidimensional composite pain scale

PURPOSE: To assess pain in the immediate postoperative period in cats submitted into two different celiotomy techniques for ovariohysterectomy. METHODS: Fourteen healthy female cats up to three years old with a mean weight 2.75kg, without breed specification, were used in this double blind experiment. The animals were randomly assigned to two treatments: I- ovariohysterectomy by lateral approach (LA) or II - by midline approach (MA). The anesthesia consisted of acepromazine (0.1 mg.kg-1) and midazolam (0.25mg.kg-1) followed isoflurane vaporization to induce and maintain hypnosis. A bolus of fentanyl (5μg.kg-1) was administered intravenously to provide intraoperative analgesia. After surgery, pain scores were assessed through a multidimensional composite pain scale at four different times. RESULTS: Generally all factors related to psychomotor changes and pain expression showed higher scores in cats neutered by LA, but only psychomotor changes and total pain score presented statistical differences (p<0.05). The animals that underwent lateral celiotomy showed higher pain scores, at 1, 4 and 6 hours after surgery. CONCLUSIONS: Multidimensional analgesic scales were highly reliable. There was a tendency for the cats neutered by lateral approach to suffer more postoperative pain, including requiring a large number of analgesic rescues. .

A cadaveric study to determine the minimum volume of methylene blue to completely color the nerves of brachial plexus in cats. An update in forelimb and shoulder surgeries

PURPOSE: To determine the minimum volume of methylene blue (MB) to completely color the brachial plexus (BP) nerves, simulating an effective anesthetic block in cats. METHODS: Fifteen adult male cat cadavers were injected through subscapular approach with volumes of 2, 3, 4, 5 and 6 ml in both forelimbs, for a total of 30 brachial plexus blocks (BPB). After infusions, the specimens were carefully dissected preserving each nervous branch. The measurement of the effective area was indicated by the impregnation of MB. Nerves were divided into four segments from the origin at the spinal level until the insertion into the thoracic limb muscles. The blocks were considered effective only when all the nerves were strongly or totally colored. RESULTS: Volumes of 2, 3 and 4 ml were considered insufficient suggesting a failed block, however, volumes of 5 and 6 ml were associated with a successful block. CONCLUSIONS: The injection of methylene blue, in a volume of 6 ml, completely colored the brachial plexus. At volumes of 5 and 6 ml the brachial plexus blocks were considered a successful regional block, however, volumes of 2, 3 and 4 ml were considered a failed regional block. .