Ultrasound-guided brachial plexus block and suspected Horner's syndrome in an alpaca ( Vicugna pacos) undergoing traumatic scapulo-humeral luxation reduction and articular capsule reconstruction

Open Vet J. 2022 Nov-Dec;12(6):1035-1038. doi: 10.5455/OVJ.2022.v12.i6.32. Epub 2022 Dec 22.


Background: Alpacas are becoming more and more diffused as pets in Europe and United Kingdom, and it is not uncommon to deal with these species in large animal referral hospitals. Unfortunately, pain assessment and treatment in llamoids remain challenging, due to their instinct of hiding signs of pain and the lack of relevant scientific literature.

Case description: This report describes the use of an ultrasound-guided brachial plexus block as part of a multimodal analgesic strategy in an alpaca undergoing surgical right shoulder luxation repair. Based on the intra-operative cardiovascular stability, the post-operative comfort level, and the minimal amount of systemic analgesics needed, it can be concluded that the block appeared effective and contributed to the peri-operative pain management. After recovery from general anesthesia, drooping of the right upper eyelid was observed and persisted for approximately 10 hours. This finding could be interpreted as a Horner's syndrome-like clinical sign and be a minor complication of the block, as previously described in other species.

Conclusion: Despite the minor complication here reported, and the difficulty in assessing intra- and post-operative nociception and pain in camelids, it can be concluded that the use of a brachial plexus block could be a valuable option when desensitization of the forelimb is required.

Keywords: Acute pain; Alpaca; Analgesia; Anesthesia; Regional anesthesia.

Publication types

  • Case Reports

MeSH terms

  • Analgesics
  • Animals
  • Brachial Plexus Block* / adverse effects
  • Brachial Plexus Block* / veterinary
  • Camelids, New World*
  • Horner Syndrome* / diagnosis
  • Horner Syndrome* / etiology
  • Horner Syndrome* / veterinary
  • Humerus
  • Pain / complications
  • Pain / veterinary
  • Ultrasonography, Interventional / veterinary


  • Analgesics