The effects of intrathecal administration of betamethasone over the dogs' spinal cord and meninges

Abstract

Purpose:To determinate the potential clinical and histological changes due the injection of betamethasone, when administered into the canine intrathecal space. Methods: Twenty one animals were included in a random and blind manner in the study. After general anesthesia, intrathecal puncture was performed and 1 ml of the random solution was injected. The G1 dogs received 0.9% saline solution, the G2 dogs received 1.75 mg betamethasone and the G3 dogs received 3.5 mg of betamethasone. The animals were clinically evaluated for 21 days and then sacrificed. The lumbar and sacral portions of the spinal cord were removed for light microscopy histological analyses. Results: No clinical changes were observed in any of the animals included in this study. No histological changes were observed in G1 animals. Inflammatory infiltration was observed in two dogs, one in G2, another in G3. Hemorrhage and necrosis were also seen in the G2 dog which inflammatory infiltration was detected. In other two dogs, one from G2 and another from G3, there was discreet fibrosis and thickness of the arachnoid layer which was focal in one and diffuse in the other. Conclusion: Intrathecal administration of betamethasone caused histological changes in the spinal cord and meninges in some of the dogs involved in this study. Key words: Adrenal Cortex Hormones. Betamethasone. Toxicity. Arachnoiditis. Dogs. RESUMOObjetivo: Determinar possíveis alterações clínicas e histológicas determinadas pela administração da betametasona no espaço subaracnóideo de cães. Métodos: Vinte e um cães foram incluídos no estudo de forma aleatória e encoberta. Depois de anestesiados, os cães foram submetidos a punção subaracóidea com injeção de 1 ml da solução sorteada. Os animais receberam solução salina 0,9% em G1, betametasona na dose de 1,75 mg em G2 e betametasona na dose de 3,5 mg em G3. Todos os animais foram mantidos em observação clínica por 21 dias, sendo posteriormente sacrificados. Porções da medula espinhal e sacral foram removidas para análise histológica por microscopia óptica. Resultados: Não foram detectadas alterações clínicas em quaisquer dos animais incluídos no estudo. Da mesma forma, nenhum animal do G1 apresentou alterações histológicas. Infiltração inflamatória foi observada em dois cães, um do G2 e outro e G3. No cão do G2 onde a infiltração inflamatória foi observada ocorreu, conjuntamente, hemorragia e necrose. Em dois cães, um de G2 e outro de G3, observou-se discreta fibrose e espessamento da aracnóide, sendo focal em um e difusa no outro. Conclusão: A administração subaracnóidea de betametasona determinou alterações histológicas em medula e meninges de alguns dos cães envolvidos no estudo.

The effect of epidurally administered dexamethasone with lignocaine for post-operative analgesia in dogs undergoing ovariohysterectomy. A dose-response study

“…intrathecal but not epidural, administration of methylprednisolone and betamethasone at high doses and continuously showed dosedependent intrathecal inflammatory reactions in dogs [25][26][27] . However, neuronal injuries, demyelination, or gliosis were not clinically observed in any animal in these studies.…”

Ovariohisterektomi Yapılan Köpeklerde Propofol Uygulamasını Takiben Bupivacaine ya da Ropivacainin İntratekal Uygulamasının Etkileri

“…It can lead to the development of hypotension, migration of local anesthetic towards the cranial area, and respiratory depression due to blockage of the diaphragm and intercostal muscles, possibly resulting in death. Therefore, the choice of local anesthesia for spinal or IT anesthesia is critical [1][2][3][6][7][8][9] . There are many studies where the advantages of bupivacaine and ropivacaine are demonstrated [1,2,16,17] .…”

“…Five minutes later, dogs were placed in the prone position. IT anesthesia was performed under aseptic conditions with either 20 mg [1] (4 mL as total dose) bupivacaine (Marcaine®, 5 mg/mL Astra Zenaca) or 30 mg [1] (4 mL as total dose) ropivacaine (Naropin® 7.5 mg/mL, Astra Zenaca) injected into the L7-S1 or L6-L7 as previously described [1,3,5,7,8] . If the spinal puncture was suspicious or unsuccessful, it was not insisted and abandoned.…”

“…If it cannot be sure that it has been entered, it should be abandoned. In this case, alternatively it can be entered in the L6-L7 range [8] . To perform the spinal puncture, the two tuberosities of the iliac bone and of the spinal process of the last lumbar vertebra are identified.…”

“…By sliding the finger in the cephalic direction, the next intervertebra space is L6-L7; this is the site where the puncture is performed using a disposable 20-25 G spinal needle which is inserted through median access at approximately 45°. After crossing the arachnoids membrane, the needle mandrel is removed to obtain free CSF leakage-proof of correct needle placement [1,3,[6][7][8][9] . Propofol, a weak analgesic, has been preferred before anesthesia to ensure quick recovery and minimal side effects, patient comfort, safety and immobility.…”