Local anaesthetics for regional and intra‐articular analgesia in the horse

Abstract

Summary During the course of a lameness examination, intra‐articular or perineural administration of a local anaesthetic is often necessary to isolate the source of pain causing lameness. Local anaesthetics are useful for intraoperative and post‐operative pain relief and may allow for elimination of, or a decrease in, general anaesthesia. Within recent years, new information has become available concerning the use of local anaesthetics for localisation of pain and for palliation of pain. New information indicates that Lidocaine is less efficacious than mepivacaine or ropivacaine in ameliorating lameness caused by pain. After administering a nerve block, loss of skin sensation may not correlate with loss of pain causing lameness. Local anaesthetic solution must be deposited within the sheath of the neurovascular bundle to be effective. The dose of a local anaesthetic, which is a factor of volume and concentration, affects potency and duration of a nerve block. Local anaesthetics are toxic to chondrocytes and synoviocytes. Lidocaine and bupivacaine appear to be more toxic than mepivacaine or ropivacaine. The clinical significance of the toxic effect of a single intra‐articular injection of local anaesthetic is yet to be determined. Sodium bicarbonate can be added to a local anaesthetic solution to increase its potency and speed of onset. Epinephrine added to local anaesthetic solution prolongs and intensifies its analgesic effect. Mixing quick‐acting, short‐duration and slow‐acting, long‐duration local anaesthetics will not result in a quick‐acting, long‐duration drug combination.

Anatomical position of the palmar/plantar nerves at the metacarpal/metatarsal distal level in horses: An in vivo study by means of ultrasonography

“…Thus, using a shorter needle in the proximodistal direction, depositing the anaesthetic subcutaneously (observing the characteristic increase in volume), is important to avoid a vascular puncture, which would result in hematomas, interfering with the anaesthetic effect or even intravascular injection. Vascular puncture occurs with some frequency and can lead to hematoma formation, which invariably hinders the action of the local anaesthetic either by dilution or formation of clots, preventing the anaesthetic diffusion, in addition to the aesthetic component affected by the presence of bleeding, even small, if the owner is following the examination (Bassage & Ross, 2011; Schumacher & Boone, 2021).…”

“…Perineural injections with anaesthetics to aid in the diagnosis of lameness in horses are widely used (Maia et al, 2020; Schumacher & Boone, 2021; Stover, 2003), being convenient in cases in which the origin and specific region of lameness have not yet been recognized even after appropriate anamnesis and detailed physical examination (Baxter & Stashak, 2011). The expectation after performing these blocks is that the animal will stop lameness, normally supporting the affected limb when the area containing the lesion is desensitized (Dyson & Kidd, 1993; Schumacher & Boone, 2021). The principle of local anaesthetics is that, when applied locally, they have a reversible effect on neural impulse conduction (Taylor & McLeod, 2020).…”

Use of an ultrasound‐guided sciatic and saphenous nerve block as a part of the multimodal analgesic management in a cria for the stabilisation of a left tibial eminence avulsion fracture

“…Locoregional anaesthesia minimises intraoperative nociceptive input, reduces postoperative pain, decreases the risk of the patient developing chronic pain and can also have a minimal alveolar concentration (MAC) sparing effect 3 . Locoregional anaesthesia has been successfully used to control pain in many different species undergoing many different procedures 3–5 . In small animals, it also has been shown to reduce the dose or frequency of administration of systemic analgesic drugs such as opioids 6,7 .…”

“…3 Locoregional anaesthesia has been successfully used to control pain in many different species undergoing many different procedures. [3][4][5] In small animals, it also has been shown to reduce the dose or frequency of administration of systemic analgesic drugs such as opioids. 6,7 The combined ultrasound (US)-guided sciatic and saphenous nerve block has been shown to be successful in desensitising the stifle in dogs, providing appropriate intraoperative and postoperative analgesia following arthroscopy and tibial plateau levelling osteotomy (TPLO).…”

In vitro and in vivo Effects of a Single Dose of Bupivacaine 5% on Donkey Chondrocytes

“…Arthroscopic knee surgery is a commonly performed orthopedic surgery ( 1 , 2 ). Postoperative pain and delay of recovery are common consequences of such surgery in humans and animals ( 3 , 4 ). Single intra-articular (IA) administration of long-acting local anesthetics is a widely utilized approach for pre- and post-operative analgesia after arthroscopic surgeries due to simplicity and low economic costs ( 5 ).…”