title: Defining the local nerve blocks for feline distal thoracic limb surgery: a cadaveric study.
abstract: Though controversial, onychectomy remains a commonly performed distal thoracic limb surgical procedure in cats. Peripheral nerve block techniques have been proposed in cats undergoing onychectomy but evidence of efficacy is lacking. Preliminary tests of the described technique using cadavers resulted in incomplete staining of nerves. The aim of this study was to develop nerve block methods based on cadaveric dissections and test these methods with cadaveric dye injections.
  
  
  
  Ten pairs of feline thoracic limbs (n = 20) were dissected and superficial branches of the radial nerve (RSbr nn.), median nerve (M n.), dorsal branch of ulnar nerve (UDbr n.), superficial branch of palmar branch of ulnar nerve (UPbrS n.) and deep branch of palmar branch of ulnar nerve (UPbrDp n.) were identified. Based on these dissections, a four-point block was developed and tested using dye injections in another six pairs of feline thoracic limbs (n = 12). Using a 25 G × 5/8 inch needle and 1 ml syringe, 0.07 ml/kg methylene blue was injected at the site of the RSbr nn., 0.04 ml/kg at the injection site of the UDbr n., 0.08 ml/kg at the injection site of the M n. and UPbrS n., and 0.01 ml/kg at the injection site of the UPbrDp n. The length and circumference of each nerve that was stained was measured.
  
  
  
  Positive staining of all nerves was observed in 12/12 limbs. The lengths stained for RSbr nn., M n., UDbr n., UPbrS n. and UPbrDp n. were 34.9 ± 5.3, 26.4 ± 4.8, 29.2 ± 4.0, 39.1 ± 4.3 and 17.5 ± 3.3 mm, respectively. The nerve circumferences stained were 93.8 ± 15.5, 95.8 ± 9.7, 100 ± 0.0, 100 ± 0.0 and 93.8 ± 15.5%, respectively.
  
  
  
  This described four-point injection method may be an effective perioperative analgesia technique for feline distal thoracic limb procedures.
authors.affiliation: Comparative Pain Research Laboratory, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA.
authors.forename: Masataka
authors.initials: M
authors.lastname: Enomoto
authors.affiliation: Comparative Pain Research Laboratory, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA Center for Comparative Medicine and Translational Research, Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA Center for Pain Research and Innovation, UNC School of Dentistry, Chapel Hill, NC, USA.
authors.forename: B Duncan X
authors.initials: BD
authors.lastname: Lascelles
authors.affiliation: Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA mgerard@ncsu.edu.
authors.forename: Mathew P
authors.initials: MP
authors.lastname: Gerard
mesh_terms: D000818:Animals; D002102:Cadaver; D002415:Cats / Q000033:anatomy & histology*; D005260:Female; D005552:Forelimb / Q000294:innervation* / Q000601:surgery; D008297:Male; D008475:Median Nerve / Q000033:anatomy & histology; D009407:Nerve Block / Q000662:veterinary*; D011826:Radial Nerve / Q000033:anatomy & histology; D014459:Ulnar Nerve / Q000033:anatomy & histology