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Home / Equine Research Bank / Animals (Basel) / Comparing Blind and Ultrasound-Guided Retrobulbar Nerve Bloc...
Animals : an open access journal from MDPI2022; 12(2); 154; doi: 10.3390/ani12020154

Comparing Blind and Ultrasound-Guided Retrobulbar Nerve Blocks in Equine Cadavers: The Training Effect.

Abstract: In standing ophthalmic surgery in horses, a retrobulbar nerve block (RNB) is often placed blindly for anesthesia and akinesia. The ultrasound (US)-guided RNB may have fewer complications, but the two techniques have only been compared once in equine cadavers. This study compares the techniques for success and complication rates and analyzes the effect of training on US guidance. Twenty-two equine cadavers were divided into three groups: blind RNBs were performed bilaterally in eight cadavers, US-guided RNBs were performed bilaterally in seven cadavers, and after US-guided training, blind RNBs were performed bilaterally in seven cadavers. All RNBs were performed by the same two inexperienced operators, and a combination of contrast medium (CM; 1.25 mL) and methylene blue dye (1.25 mL) were injected (2.5 mL total volume). Needle positioning in the periorbita and the distance of the CM to the optic foramen were assessed using computerized tomography (CT). Dye spreading was evaluated by dissection. In group 1, 37.5% of the injections were in the optimal central position in the periorbita; in group 2, 75% and in group 3, 71.4%. There was no significant difference between the groups regarding needle position (groups 1 and 2 = 0.056; groups 1 and 3 = 0.069, groups 2 and 3 = 0.8). The mean CM distribution distance was not significantly different between all groups. Group 1 had 18.75% intraocular injections versus 0% in group 2 and 7.1% in group 3 (not significant). US guidance showed no significant increases in accuracy nor decreases in complications. However, the effects on accuracy showed a trend towards significant improvement, and larger scale follow-up studies might show significant training effects on US guidance.
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Publication Date: 2022-01-09 PubMed ID: 35049776PubMed Central: PMC8772549DOI: 10.3390/ani12020154Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research compared the effectiveness and safety of two anesthesia techniques in horse eye surgery: a blind retrobulbar nerve block (RNB) and an ultrasound-guided RNB. The study also investigated how training can influence the accuracy of using ultrasound guidance. The results showed no significant difference in accuracies or complications between the techniques, but showed potential for improvement with further training in ultrasound guidance.

Details of the Research

  • The research was conducted on Twenty-two equine (horse) cadavers. The cadavers were divided into three groups: those that received blind RNBs, those that received ultrasound-guided RNBs, and those that received blind RNBs after ultrasound-guided training.
  • Each RNB was performed by the same two operators, who had no prior experience. A combination of contrast medium and methylene blue dye were injected. Needle positioning and the proximity of the contrast medium to the optic foramen were evaluated using Computerized Tomography (CT). Dissection was used to evaluate dye spreading.

Research Results

  • In the first group (blind RNBs without training), 37.5% of the injections were optimally placed in the central position of the periorbita, a section of the eye. In the second group (ultrasound-guided RNBs), this figure rose to 75%. In the final group (blind RNBs post-training), the figure was 71.4%.
  • There was no significant difference in needle position between the groups. Similarly, the average distribution distance of the contrast medium was not significantly different across all groups.
  • In the first group, there were 18.75% intraocular injections, compared to 0% in the second group and 7.1% in the third group. Despite the apparent trend, the differences were not statistically significant.
  • While no significant changes in accuracy or complication levels were seen with ultrasound guidance, there was a trend towards potentially significant improvements with additional training in this technique.

Implication of Results

  • The use of ultrasound-guided RNB compared to blind RNB did not significantly improve accuracy nor decrease complications in equine ophthalmic surgeries, according to the parameters of this study.
  • However, the process did show a non-significant trend towards improved results with ultrasound-guided training, which suggests that further large-scale studies might confirm the effectiveness of such training.

Cite This Article

APA
Hermans H, Lloyd-Edwards RA, Ferrão-van Sommeren AJH, Tersmette AA, Schouten JCM, Serra Bragança FM, van Loon JPAM. (2022). Comparing Blind and Ultrasound-Guided Retrobulbar Nerve Blocks in Equine Cadavers: The Training Effect. Animals (Basel), 12(2), 154. https://doi.org/10.3390/ani12020154

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 12
Issue: 2
PII: 154

Researcher Affiliations

Hermans, Hanneke
  • Department of Clinical Sciences, Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112-114, 3584 CM Utrecht, The Netherlands.
Lloyd-Edwards, Ralph A
  • Department of Clinical Sciences, Diagnostic Imaging, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 108, 3584 CM Utrecht, The Netherlands.
  • VetCT, St John's Innovation Centre, Cowley Road, Cambridge CB4 0WS, UK.
Ferrão-van Sommeren, Aukje J H
  • Diergeneeskundig Centrum Maas en Waal, Klepperheide 16, 6651 KM Druten, The Netherlands.
Tersmette, Anne A
  • Department of Clinical Sciences, Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112-114, 3584 CM Utrecht, The Netherlands.
Schouten, Jacobine C M
  • Department of Clinical Sciences, Anatomy and Physiology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CM Utrecht, The Netherlands.
Serra Bragança, Filipe M
  • Department of Clinical Sciences, Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112-114, 3584 CM Utrecht, The Netherlands.
van Loon, Johannes P A M
  • Department of Clinical Sciences, Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112-114, 3584 CM Utrecht, The Netherlands.
  • Sporthorse Medical Diagnostic Centre (SMDC), Hooge Wijststraat 7, 5384 RC Bernheze, The Netherlands.

Conflict of Interest Statement

The authors declare no conflict of interest.

References

This article includes 35 references
  1. Ghadiali Q, Ghadiali LK, Schiff WM, Odel JG. CONTRALATERAL ANESTHESIA IN TWO PATIENTS AFTER RETROBULBAR BLOCK.. Retin Cases Brief Rep 2018 Spring;12(2):97-99.
    doi: 10.1097/ICB.0000000000000455pubmed: 27749747google scholar: lookup
  2. Kostadinov I, Hostnik A, Cvenkel B, Potočnik I. Brainstem Anaesthesia after Retrobulbar Block.. Open Med (Wars) 2019;14:287-291.
    doi: 10.1515/med-2019-0025pmc: PMC6419387pubmed: 30886900google scholar: lookup
  3. Kumar CM, Dowd TC. Complications of ophthalmic regional blocks: their treatment and prevention.. Ophthalmologica 2006;220(2):73-82.
    doi: 10.1159/000090570pubmed: 16491028google scholar: lookup
  4. Palte HD. Ophthalmic regional blocks: management, challenges, and solutions.. Local Reg Anesth 2015;8:57-70.
    doi: 10.2147/LRA.S64806pmc: PMC4550180pubmed: 26316814google scholar: lookup
  5. Rizzo S, Giorni A, Savastano A. Imaging of Ocular Perforation After Retrobulbar Block.. JAMA Ophthalmol 2016 Nov 10;134(11):e162716.
    doi: 10.1001/jamaophthalmol.2016.2716pubmed: 27832280google scholar: lookup
  6. Marhofer P, Harrop-Griffiths W, Kettner SC, Kirchmair L. Fifteen years of ultrasound guidance in regional anaesthesia: part 1.. Br J Anaesth 2010 May;104(5):538-46.
    doi: 10.1093/bja/aeq069pubmed: 20364022google scholar: lookup
  7. Marhofer P, Harrop-Griffiths W, Willschke H, Kirchmair L. Fifteen years of ultrasound guidance in regional anaesthesia: Part 2-recent developments in block techniques.. Br J Anaesth 2010 Jun;104(6):673-83.
    doi: 10.1093/bja/aeq086pubmed: 20418267google scholar: lookup
  8. Marhofer P, Greher M, Kapral S. Ultrasound guidance in regional anaesthesia.. Br J Anaesth 2005 Jan;94(1):7-17.
    doi: 10.1093/bja/aei002pubmed: 15277302google scholar: lookup
  9. Stoppini R, Gilger BC. Equine ocular examination basic techniques. In: Gilger B.C., editor. Equine Ophthalmology. 3rd ed. John Wiley & Sons Inc.; Hoboken, NJ, USA: 2017. pp. 1–39.
  10. Hermans H, Veraa S, Wolschrijn CF, van Loon JPAM. Local anesthetic techniques for the equine head, towards guided techniques and new applications. Equine Vet. Educ. 2019;31:432–440.
    doi: 10.1111/eve.12757google scholar: lookup
  11. Tremaine WH. Local analgesic techniques for the equine head. Equine Vet. Educ. 2007;19:495–503.
    doi: 10.2746/095777307X207114google scholar: lookup
  12. O'Neill HD, Garcia-Pereira FL, Mohankumar PS. Ultrasound-guided injection of the maxillary nerve in the horse.. Equine Vet J 2014 Mar;46(2):180-4.
    doi: 10.1111/evj.12106pubmed: 23679076google scholar: lookup
  13. Campoy L, Morris TB, Ducharme NG, Gleed RD, Martin-Flores M. Unilateral cervical plexus block for prosthetic laryngoplasty in the standing horse.. Equine Vet J 2018 Nov;50(6):727-732.
    doi: 10.1111/evj.12956pubmed: 29675966google scholar: lookup
  14. Küls N, Trujanovic R, Otero PE, Larenza-Menzies MP. 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 2020 Jul;90:102994.
    doi: 10.1016/j.jevs.2020.102994pubmed: 32534772google scholar: lookup
  15. Morath U, Luyet C, Spadavecchia C, Stoffel MH, Hatch GM. Ultrasound-guided retrobulbar nerve block in horses: a cadaveric study.. Vet Anaesth Analg 2013 Mar;40(2):205-11.
    doi: 10.1111/j.1467-2995.2012.00780.xpubmed: 23057999google scholar: lookup
  16. Leigh H, Gozalo-Marcilla M, Esteve V, Gutiérrez Bautista ÁJ, Martin Gimenez T, Viscasillas J. Description of a novel ultrasound guided peribulbar block in horses: a cadaveric study.. J Vet Sci 2021 Mar;22(2):e22.
    doi: 10.4142/jvs.2021.22.e22pmc: PMC8007447pubmed: 33774938google scholar: lookup
  17. Labelle AL, Clark-Price SC. Anesthesia for ophthalmic procedures in the standing horse.. Vet Clin North Am Equine Pract 2013 Apr;29(1):179-91.
    doi: 10.1016/j.cveq.2012.12.001pubmed: 23498052google scholar: lookup
  18. de Linde Henriksen M, Brooks DE. Standing ophthalmic surgeries in horses.. Vet Clin North Am Equine Pract 2014 Apr;30(1):91-110.
    doi: 10.1016/j.cveq.2013.11.012pubmed: 24680208google scholar: lookup
  19. Menzies RA, Easley J. Standing equine dental surgery.. Vet Clin North Am Equine Pract 2014 Apr;30(1):63-90.
    doi: 10.1016/j.cveq.2013.11.002pubmed: 24680207google scholar: lookup
  20. McKinney RA. The retrobulbar block: A review of techniques used and reported complications. Equine Vet. Educ. 2020;33:332–336.
    doi: 10.1111/eve.13351google scholar: lookup
  21. Yang VY, Eaton JS, Harmelink K, Hetzel SJ, Sanchez A, Lund JR, Smith LJ. Retrobulbar lidocaine injection via the supraorbital fossa is safe in adult horses but produces regionally variable periocular anaesthesia.. Equine Vet J 2021 Aug 16;.
    doi: 10.1111/evj.13496pubmed: 34396584google scholar: lookup
  22. Alhassan MB, Kyari F, Ejere HO. Peribulbar versus retrobulbar anaesthesia for cataract surgery.. Cochrane Database Syst Rev 2015 Jul 2;2015(7):CD004083.
    doi: 10.1002/14651858.CD004083.pub3pmc: PMC7175781pubmed: 26133124google scholar: lookup
  23. Eke T, Thompson JR. The National Survey of Local Anaesthesia for Ocular Surgery. II. Safety profiles of local anaesthesia techniques.. Eye (Lond) 1999 Apr;13 ( Pt 2):196-204.
    doi: 10.1038/eye.1999.50pubmed: 10450381google scholar: lookup
  24. Riad W, Akbar F. Ophthalmic regional blockade complication rate: a single center audit of 33,363 ophthalmic operations.. J Clin Anesth 2012 May;24(3):193-5.
    doi: 10.1016/j.jclinane.2011.07.012pubmed: 22459339google scholar: lookup
  25. Scholle TM. Anesthesia for Ocular Surgery.. Int Ophthalmol Clin 2020 Fall;60(4):41-60.
    doi: 10.1097/IIO.0000000000000337pubmed: 33093316google scholar: lookup
  26. Gilger B, Davidson M. How to prepare for ocular surgery in the standing horse. Proc. Am. Assoc. Equine Practnrs. 2002;48:266–271.
  27. Pollock PJ, Russell T, Hughes TK, Archer MR, Perkins JD. Transpalpebral eye enucleation in 40 standing horses.. Vet Surg 2008 Apr;37(3):306-9.
    doi: 10.1111/j.1532-950X.2008.00382.xpubmed: 18394080google scholar: lookup
  28. Stadler S, Dennler M, Hetzel U, Del Chicca F, Hoey S, Spiess BM, Voelter K, Pot SA. Sub-Tenon's injection in equine cadaver eyes: MRI visualization of anesthetic fluid distribution and comparison of two different volumes.. Vet Ophthalmol 2017 Nov;20(6):488-495.
    doi: 10.1111/vop.12452pubmed: 28008696google scholar: lookup
  29. Ahn J, Jeong M, Park Y, Lee Y, Lee E, Kim S, Lee I, Seo K. Comparison of systemic atracurium, retrobulbar lidocaine, and sub-Tenon's lidocaine injections in akinesia and mydriasis in dogs.. Vet Ophthalmol 2013 Nov;16(6):440-5.
    doi: 10.1111/vop.12026pubmed: 23347234google scholar: lookup
  30. Roman SJ, Chong Sit DA, Boureau CM, Auclin FX, Ullern MM. Sub-Tenon's anaesthesia: an efficient and safe technique.. Br J Ophthalmol 1997 Aug;81(8):673-6.
    doi: 10.1136/bjo.81.8.673pmc: PMC1722293pubmed: 9349156google scholar: lookup
  31. Chen XX, Trivedi V, AlSaflan AA, Todd SC, Tricco AC, McCartney CJL, Boet S. Ultrasound-Guided Regional Anesthesia Simulation Training: A Systematic Review.. Reg Anesth Pain Med 2017 Nov Dec;42(6):741-750.
    doi: 10.1097/AAP.0000000000000639pubmed: 28759501google scholar: lookup
  32. da Silva LCBA, Sellera FP, Gargano RG, Rossetto TC, Gomes GB, Miyahira FT, Futema F, Cortopassi SRG. Preliminary study of a teaching model for ultrasound-guided peripheral nerve blockade and effects on the learning curve in veterinary anesthesia residents.. Vet Anaesth Analg 2017 May;44(3):684-687.
    doi: 10.1016/j.vaa.2016.08.004pubmed: 28262499google scholar: lookup
  33. Shilo-Benjamini Y, Pascoe PJ, Maggs DJ, Kass PH, Wisner ER. Retrobulbar and peribulbar regional techniques in cats: a preliminary study in cadavers.. Vet Anaesth Analg 2013 Nov;40(6):623-31.
    doi: 10.1111/vaa.12060pubmed: 23782789google scholar: lookup
  34. Robertson SA. Standing sedation and pain management for ophthalmic patients.. Vet Clin North Am Equine Pract 2004 Aug;20(2):485-97.
    doi: 10.1016/j.cveq.2004.04.005pubmed: 15271436google scholar: lookup
  35. Sohn HJ, Moon HS, Nam DH, Paik HJ. Effect of volume used in sub-Tenon's anesthesia on efficacy and intraocular pressure in vitreoretinal surgery.. Ophthalmologica 2008;222(6):414-21.
    doi: 10.1159/000161556pubmed: 18849625google scholar: lookup

Citations

This article has been cited 1 times.
  1. Marzok M, Almubarak A, Elkhidr RY, Elkawi MA, El-Sherif MW. Ultrasound-guided peribulbar block in dromedary camels: a descriptive cadaveric study. BMC Vet Res 2025 Jul 2;21(1):431.
    doi: 10.1186/s12917-025-04891-wpubmed: 40605014google scholar: lookup
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