{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T15:23:49Z","timestamp":1774452229033,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T00:00:00Z","timestamp":1774224000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Animals"],"abstract":"<jats:p>Regional anaesthesia of the equine anogenital tract is limited to local infiltration, extradural, blind palpation and nerve stimulator-guided techniques which risk iatrogenic damage, recumbency and ataxia. This study aimed to describe and assess the feasibility of transcutaneous ultrasound-guided (USG) pudendal nerve staining in equine cadavers. An initial pilot phase used two fresh equine cadavers and one standing unsedated horse to image the intrapelvic anatomy using ultrasound. One fixed equine cadaver specimen was also dissected to identify the pudendal nerve and refine the dissection approach. The main study of six fresh equine cadavers used ultrasound to identify the landmarks of pelvic brim, pelvic urethra, rectum and semimembranosus musculature. Bilateral USG injection of 15 mL of methylene blue dye was performed, followed by anatomical dissection. The pudendal nerve was stained in 41.7% of injections, with an average staining length of 8.26 cm. Landmarks guiding dye injection were reliably imaged in all cadavers. Imaging of the pudendal nerve was not possible. Staining of the sciatic nerve did not occur. Transcutaneous USG pudendal nerve staining with methylene blue dye (15 mL) is possible in equine cadavers. However, this technique cannot be currently recommended. Further refinement in cadavers is necessary to improve the staining success rate.<\/jats:p>","DOI":"10.3390\/ani16060995","type":"journal-article","created":{"date-parts":[[2026,3,23]],"date-time":"2026-03-23T15:54:53Z","timestamp":1774281293000},"page":"995","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Preliminary Investigation of a Transcutaneous Ultrasound-Guided Technique for Pudendal Nerve Block in Six Horse Cadavers"],"prefix":"10.3390","volume":"16","author":[{"given":"Elliot","family":"Pye","sequence":"first","affiliation":[{"name":"The Royal (Dick) School of Veterinary Studies, Easter Bush Campus, The University of Edinburgh, Roslin EH25 9RG, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Miguel Gozalo","family":"Marcilla","sequence":"additional","affiliation":[{"name":"The Royal (Dick) School of Veterinary Studies, Easter Bush Campus, The University of Edinburgh, Roslin EH25 9RG, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9270-8609","authenticated-orcid":false,"given":"Juliet C.","family":"Duncan","sequence":"additional","affiliation":[{"name":"The Royal (Dick) School of Veterinary Studies, Easter Bush Campus, The University of Edinburgh, Roslin EH25 9RG, UK"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2026,3,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"32","DOI":"10.1177\/0310057X0903700115","article-title":"A prospective randomised controlled trial of ultrasound guided versus nerve stimulation guided distal sciatic nerve block at the popliteal fossa","volume":"37","author":"Braak","year":"2009","journal-title":"Anaesth. Intensive Care"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"K\u00fcls, N., Trujanovic, R., Otero, P.E., and Larenza-Menzies, M.P. (2020). Ultrasound-Guided Transversus Abdominis Plane Block in Shetland Ponies: A Description of a Three-Point Injection Technique and Evaluation of Potential Analgesic Effects. J. Equine Vet. Sci., 90.","DOI":"10.1016\/j.jevs.2020.102994"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Leigh, H., Gozalo Marcilla, M., Esteve, V., Bautista, \u00c1.J.G., Gimenez, T.M., and Viscasillas, J. (2021). Description of a novel ultrasound guided peribulbar block in horses: A cadaveric study. J. Vet. Sci., 22.","DOI":"10.4142\/jvs.2021.22.e22"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1111\/evj.12106","article-title":"Ultrasound-guided injection of the maxillary nerve in the horse","volume":"46","author":"Mohankumar","year":"2014","journal-title":"Equine Vet. J."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"525","DOI":"10.1016\/j.vaa.2025.06.005","article-title":"The Confidential Enquiry into Perioperative Equine Fatalities: Phase 4 (CEPEF4). A worldwide observational, prospective, multicentre cohort study in 2025","volume":"52","author":"Redondo","year":"2025","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"578","DOI":"10.1136\/inp.e7507","article-title":"Sedation and analgesia in the standing horse 2. Local anaesthesia and analgesia techniques","volume":"34","author":"Michou","year":"2012","journal-title":"Practice"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.cveq.2016.11.001","article-title":"Nonsteroidal Anti-inflammatory Drug Use in Horses","volume":"33","author":"Knych","year":"2017","journal-title":"Vet. Clin. N. Am. Equine Pract."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"493","DOI":"10.1016\/j.cveq.2010.07.002","article-title":"Opioid Analgesia in Horses","volume":"26","author":"Clutton","year":"2010","journal-title":"Vet. Clin. N. Am. Equine Pract."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"133","DOI":"10.1016\/j.cvfa.2015.09.003","article-title":"Ultrasound-Guided Nerve Block Anesthesia","volume":"32","author":"Re","year":"2016","journal-title":"Vet. Clin. N. Am. Food Anim. Pract."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1053\/j.ctep.2007.05.008","article-title":"Epidural and Spinal Anesthesia and Analgesia in the Equine","volume":"6","author":"Natalini","year":"2007","journal-title":"Clin. Tech. Equine Pract."},{"key":"ref_11","unstructured":"Budras, K.D., Sack, W.O., and Rock, S. (2007). Chapter 9: Pelvis, Inguinal Region, and Urogenital Organs. Anatomy of the Horse, CRC Press LLC. [5th ed.]."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1016\/j.tvjl.2016.10.004","article-title":"Development of a peripheral nerve stimulator-guided technique for equine pudendal nerve blockade","volume":"217","author":"Gallacher","year":"2016","journal-title":"Vet. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"457","DOI":"10.1016\/0093-691X(85)90052-4","article-title":"Pudendal and caudal rectal nerve blocks in the horse\u2014An anesthetic procedure for reproductive surgery","volume":"24","author":"Schumacher","year":"1985","journal-title":"Theriogenology"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"901","DOI":"10.1177\/1098612X13485482","article-title":"Development of an ultrasound-guided technique for pudendal nerve block in cat cadavers","volume":"15","author":"Adami","year":"2013","journal-title":"J. Feline Med. Surg."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"340","DOI":"10.1177\/1098612X13509082","article-title":"Ultrasound-guided pudendal nerve block in cats undergoing perineal urethrostomy: A prospective, randomised, investigator-blind, placebo-controlled clinical trial","volume":"16","author":"Adami","year":"2014","journal-title":"J. Feline Med. Surg."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"81","DOI":"10.21608\/avmj.2017.170961","article-title":"Ultrasound-Guided Pudendal Nerve Block in Male Donkeys","volume":"63","author":"Nazih","year":"2017","journal-title":"Assiut Vet. Med. J."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1016\/j.vaa.2024.10.132","article-title":"Ultrasound-guided pudendal block in the dog: A cadaver study and case report","volume":"52","author":"Duffee","year":"2024","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"438","DOI":"10.1016\/j.vaa.2025.03.012","article-title":"Ultrasound-guided ischiorectal fossa block targeting the pudendal nerve in dogs: A cadaveric study","volume":"52","author":"Zumstein","year":"2025","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"236","DOI":"10.1016\/j.vaa.2024.11.043","article-title":"Description of an ultrasound-guided technique for pudendal nerve block in sheep","volume":"52","author":"Re","year":"2025","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"610","DOI":"10.1097\/AAP.0000000000000447","article-title":"Pudendal versus caudal block in children undergoing hypospadias surgery: A randomized controlled trial","volume":"41","author":"Kendigelen","year":"2016","journal-title":"Reg. Anesth. Pain. Med."},{"key":"ref_21","doi-asserted-by":"crossref","unstructured":"Mantica, G., Leonardi, R., Diaz, R., Malinaric, R., Parodi, S., Tappero, S., Paraboschi, I., \u00c1lvarez-Maestro, M., Yuen-Chun Teoh, J., and Garriboli, M. (2022). Reporting ChAracteristics of cadaver training and sUrgical studies: The CACTUS guidelines. Int. J. Surg., 101.","DOI":"10.1016\/j.ijsu.2022.106619"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1016\/j.jclinane.2010.12.005","article-title":"Analgesic efficacy of ultrasound-guided regional anesthesia: A meta-analysis","volume":"23","author":"Gelfand","year":"2011","journal-title":"J. Clin. Anesth."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"630","DOI":"10.1097\/ACO.0b013e3280101423","article-title":"Ultrasound guidance in peripheral regional anesthesia: Philosophy, evidence-based medicine, and techniques","volume":"19","author":"Sites","year":"2006","journal-title":"Curr. Opin. Anaesthesiol."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"581","DOI":"10.1136\/rapm-2021-102506","article-title":"Anatomical basis of fascial plane blocks","volume":"46","author":"Chin","year":"2021","journal-title":"Reg. Anesth. Pain. Med."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"439","DOI":"10.1016\/j.vaa.2023.05.003","article-title":"A non-inferiority study comparing the ultrasound-guided parasacral with a novel greater ischiatic notch plane approach in canine cadavers","volume":"50","author":"Koehler","year":"2023","journal-title":"Vet. Anaesth. Analg."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"111","DOI":"10.1515\/macvetrev-2015-0064","article-title":"Pudendal nerve block in male goats: Comparison of ischiorectal fossa and ischial arch approaches using low volume 1% lignocaine hydrochloride","volume":"39","author":"Fazili","year":"2016","journal-title":"Maced. Vet. Rev."},{"key":"ref_27","unstructured":"Dugdale, A.H.A., Beaumont, G., Bradbrook, C., and Gurney, M. (2020). Local Anaesthetic Techniques: Horses. Veterinary Anaesthesia Principles to Practice, Wiley-Blackwell. [2nd ed.]."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/S0749-0739(02)00010-X","article-title":"Epidural anesthesia and analgesia in horses","volume":"18","author":"Robinson","year":"2002","journal-title":"Vet. Clin. Equine Pract."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"567","DOI":"10.1111\/eve.12911","article-title":"The outcomes of epidural anaesthesia in horses with perineal and tail melanomas: Complications associated with ataxia and the risks of rope recovery","volume":"31","author":"Bird","year":"2019","journal-title":"Equine Vet. Educ."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"374","DOI":"10.1093\/bjaed\/mkw026","article-title":"Challenges, solutions, and advances in ultrasound-guided regional anaesthesia","volume":"16","author":"Henderson","year":"2016","journal-title":"BJA Educ."},{"key":"ref_31","unstructured":"Pye, E., Gozalo Marcilla, M., and Duncan, J.C. (2022, January 1\u20132). Ultrasound-guided brachial plexus block in a Miniature Shetland Pony: A case report. Proceedings of the Association of Veterinary Anaesthetists\u2019 Meeting, Bern, Switzerland."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"498","DOI":"10.1111\/vec.12102","article-title":"Evaluation of ultrasound-guided vascular access in dogs","volume":"23","author":"Chamberlin","year":"2013","journal-title":"J. Vet. Emerg. Crit. Care"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1016\/j.vaa.2021.11.004","article-title":"Development of an ultrasound-guided transgluteal injection of the pudendal nerve in cats: A cadaveric study","volume":"49","author":"Briley","year":"2022","journal-title":"Vet. Anaesth. Analg."}],"container-title":["Animals"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2615\/16\/6\/995\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T14:22:12Z","timestamp":1774448532000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2615\/16\/6\/995"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,23]]},"references-count":33,"journal-issue":{"issue":"6","published-online":{"date-parts":[[2026,3]]}},"alternative-id":["ani16060995"],"URL":"https:\/\/doi.org\/10.3390\/ani16060995","relation":{},"ISSN":["2076-2615"],"issn-type":[{"value":"2076-2615","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,3,23]]}}}