Blind versus ultrasound-guided maxillary nerve block in donkeys

  • Usama Hagag
    Correspondence: Usama Hagag, Department of Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Beni-Suef University, Al Shamla st., Beni-Suef 62511, Egypt.
    Department of Surgery, Anesthesiology and Radiology, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
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  • Mohamed G. Tawfiek
    Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Beni-Suef University, Beni-Suef, Egypt
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      To describe the ‘blind’ and ultrasound-guided approaches to block the maxillary nerve in donkeys. To compare the success and complication rates between the ‘blind’ and ultrasound-guided techniques based on staining of nerves and other structures in cadavers and assessing level of analgesia in live animals.

      Study design

      Prospective anatomical and experimental study.


      Eighteen cadaver heads and nine adult live donkeys.


      Phase 1: the anatomical characteristics of the maxillary nerve and its related structures were investigated within the pterygopalatine fossa in five cadavers. Phase 2: 0.1 mL of methylene blue dye was injected blindly and via ultrasound guidance in 13 cadavers to stain the left and right maxillary nerves, respectively. Nerve staining and dye spreading were evaluated through cadaver dissection. Phase 3: the former procedures were applied in nine live donkeys using lidocaine hydrochloride 2% and the onset of analgesia was verified through needle pricking at the naris.


      Ultrasound-guided deposition of methylene blue dye in cadavers and lidocaine injection in live animals were successful in all instances (accuracy = 100%) without inadvertent vascular penetration. Using the ‘blind’ technique, misdirection and intravascular deposition of dye were reported in four cadavers (accuracy = 69.2%) and neurovascular trauma was observed in live donkeys (five cases). Loss of cutaneous sensation in the ipsilateral naris was earlier in the ultrasound-guided approach (10.9 ± 1.8 minutes) than in the ‘blind’ technique (27.8 ± 3.2 minutes; p < 0.001).

      Conclusions and clinical relevance

      An ultrasound-guided maxillary nerve blockade proved very practical and can be used to block the maxillary nerve with a high degree of accuracy while avoiding vascular penetration. Further studies are mandatory to validate its analgesic effectiveness in clinical situations.


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        • Bardell D.
        • Iff I.
        • Mosing M.
        A cadaver study comparing two approaches to perform a maxillary nerve block in the horse.
        Equine Vet J. 2010; 42: 721-725
        • Campoy L.
        • Bezuidenhout A.J.
        • Gleed R.D.
        • et al.
        Ultrasound-guided approach for axillary brachial plexus, femoral nerve, and sciatic nerve blocks in dogs.
        Vet Anaesth Analg. 2010; 37: 144-153
        • Casati A.
        • Baciarello M.
        • Di Cianni S.
        • et al.
        Effects of ultrasound guidance on the minimum effective anesthetic volume required to block the femoral nerve.
        Br J Anaesth. 2007; 98: 823-827
        • Echeverry D.F.
        • Gil F.
        • Laredo F.
        • et al.
        Ultrasound-guided block of the sciatic and femoral nerves in dogs: a descriptive study.
        Vet J. 2010; 186: 210-215
        • Echeverry D.F.
        • Gil F.
        • Laredo F.
        • et al.
        Ultrasound-guided ‘two-in-one’ femoral and obturator nerve block in the dog: an anatomical study.
        Vet Anaesth Analg. 2012; 39: 611-617
        • Falyar C.R.
        Ultrasound in anesthesia: applying scientific principles to clinical practice.
        AANA J. 2010; 78: 332-340
        • Gray A.T.
        Ultrasound-guided regional anesthesia: Current state of the art.
        Anesthesiology. 2006; 104: 368-373
        • Joubert K.E.
        • Briggs P.
        • Gerber D.
        • et al.
        The sedative and analgesic effects of detomidine-butorphanol and detomidine alone in donkeys.
        J S Afr Vet Assoc. 1999; 70: 112-118
        • König H.E.
        • Liebich H.G.
        Veterinary Anatomy of Domestic Mammals: Textbook and Colour Atlas.
        6th edn. Schattauer GmbH, Germany2014
        • Lizarraga I.
        • Beths T.
        A comparative study of xylazine-induced mechanical hypoalgesia in donkeys and horses.
        Vet Anaesth Analg. 2012; 39: 533-538
        • Lizarraga I.
        • Sumano H.
        • Brumbaugh G.W.
        Pharmacologic and pharmacokinetic differences between donkeys and horses.
        Equine Vet Educ. 2004; 16: 102-112
        • Michela R.E.
        • Blanco-Murcia J.
        • Villaescusa F.A.
        • et al.
        Ultrasound-guided anesthetic blockade of the pelvic limb in calves.
        Vet J. 2014; 200: 434-439
        • O'Neill H.D.
        • Garcia-Pereira F.L.
        • Mohakumar P.S.
        • et al.
        Ultrasound-guided injection of the maxillary nerve in the horse.
        Equine Vet J. 2014; 46: 180-184
        • Oberndorfer U.
        • Marhofer P.
        • Bösenberg A.
        • et al.
        Ultrasonographic guidance for sciatic and femoral nerve blocks in children.
        Br J Anaesth. 2007; 98: 797-801
        • Sites B.D.
        • Brull R.
        Ultrasound guidance in peripheral regional anesthesia: philosophy, evidence-based medicine, and techniques.
        Curr Opin Anaesthesiol. 2006; 19: 630-639
        • Staszyk C.
        • Bienert A.
        • Bäumer W.
        • et al.
        Simulation of local anaesthetic nerve block of the infraorbital nerve within the pterygopalatine fossa: anatomical landmarks defined by computed tomography.
        Res Vet Sci. 2008; 85: 399-406
        • Taylor T.S.
        • Matthews N.S.
        • Blanchard T.
        Introduction to donkeys in the U.S.: elementary assology.
        New Engl J Large Anim Health. 2001; 1: 21-28
        • Tremaine W.H.
        Local analgesic techniques for the equine head.
        Equine Vet Educ. 2007; 19: 495-503
        • Williams S.R.
        • Chouinard P.
        • Arcand G.
        • et al.
        Ultrasound guidance speeds execution and improves the quality of supraclavicular block.
        Anesth Analg. 2003; 97: 1518-1523