Intrathecal anaesthesia in Tegus (Salvator merianae)

Hello there! In this video, we show you the intrathecal anaesthesia in Tegus (Salvator merianae). This procedure has been used for surgery in tail, cloaca, hind limbs and distal part of the coelomic cavity in lizards.

Spinal anaesthesia in reptiles is a bit different from mammalian because the reptilian spinal cord has no subarachnoid space. Thus, they have two meninges: the outer membrane is the dura mater and the inner membrane the leptomeninx, and cerebrospinal fluid flows between them. So, it is correct to say intrathecal anaesthesia rather than epidural anaesthesia in reptiles.

The spinal cord of reptiles extends to the tail's tip, and they do not have a cauda equina. Furthermore, in many reptilian species, the spinal cord only fills a portion of the spinal canal, with as much as 50% of the canal available in some species.

To perform this technique, we have to puncture any intervertebral space after asepsis. The size needle and syringe should be selected according to the animal’s size. We have used to use 28G ½ inch needle in 1mL syringe. After perforation, we advance the needle into the spinal canal at 30-45o angle. Sometimes we can see cerebrospinal fluid comes up to the syringe. That’s fine. Some blood may come up as well. If an excessive amount of blood is aspirated, the needle should be repositioned until no further blood is aspirated. We must inject anaesthetic solution after 15-20 seconds.

The local anaesthetic drugs recommended are the same as in mammals. We can define drug volume based on the animal’s weight, being 0,1mL/kg, producing motor block on the tail, cloaca, hind limbs and distal part of the coelomic cavity. This technique is pretty the same as in red-eared slider.

About drug doses, we can use lidocaine (2 - 4 mg/kg) which promotes motor block for about one hour, or bupivacaine (1 mg/kg), lasted about 2 – 3 hours.

Do you want to see how to do it? Go the the video

To watch other procedures, go to this link!


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