Ultrasound-guided rectus sheath block injections in miniature swine cadavers: technique description and distribution of two injectate volumes

Published:January 11, 2022DOI:



      To describe a technique for ultrasound-guided rectus sheath block in pigs and the distribution of two injectate volumes.

      Study design

      Experimental study.


      A total of 11 Hanford miniature pig cadavers.


      The lateral border of each rectus abdominis muscle in 10 freshly euthanized pigs was visualized with a 6-15 MHz linear ultrasound probe. A spinal needle was inserted 1 cm cranial to the umbilicus, in-plane and medial to the probe, and advanced dorsal-to-lateral until the tip was ventral to the internal rectus sheath. Pigs were injected bilaterally with high volume (HV; 0.8 mL kg−1) and low volume (LV; 0.5 mL kg−1), of 1:1 solution of 1% methylene blue and 0.5% bupivacaine (1 mg kg−1) diluted with 0.9% saline. Nerve staining > 1 cm circumferentially was determined by dissection 15 minutes postinjection. The Clopper–Pearson method was used to calculate 95% confidence intervals (CI) for proportions of stained nerves. In another pig, a 1:1 solution of 1% methylene blue and 74% ioversol contrast was injected, and computed tomography performed at 15 minute intervals after injection.


      Nerve staining for thoracic (T) spinal nerves T9, T10, T11, T12, T13 and T14 occurred 20%, 60%, 90% 100%, 100% and 50%, and 0%, 20%, 90%, 100%, 100% and 50% of the time in HV and LV treatments, respectively. More nerves were stained in treatment HV in 4/10 animals (40%, 95% CI: 12%, 74%) than in treatment LV (0%, 95% CI: 0%, 31%). The greatest spread of injectate occurred within the first 15 minutes after injection.

      Conclusions and clinical relevance

      Staining of T11–T14 nerves was the same in both treatments but more T9–T10 nerves were stained by the higher volume. Based on distribution of dye, a rectus sheath block may only provide ventral abdominal analgesia cranial to the umbilicus in pigs.


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        • Anil L.
        • Anil S.S.
        • Deen J.
        Pain detection and amelioration in animals on the farm: issues and options.
        J Appl Anim Welf Sci. 2005; 8: 261-278
        • Baldo C.F.
        • Almeida D.
        • Wendt-Hornickle E.
        • Guedes A.
        Transversus abdominis plane block in ponies: a preliminary anatomical study.
        Vet Anaesth Analg. 2018; 45: 392-396
        • Bashandy G.M.
        • Elkholy A.H.
        Reducing postoperative opioid consumption by adding an ultrasound-guided rectus sheath block to multimodal analgesia for abdominal cancer surgery with midline incision.
        Anesth Pain Med. 2014; 4e18263
        • Bradbury A.G.
        • Eddleston M.
        • Clutton R.E.
        Pain management in pigs undergoing experimental surgery; a literature review (2012-4).
        Br J Anaesth. 2016; 116: 37-45
      1. Bradley OC (1922) The Topographical Anatomy of the Thorax and Abdomen of the Horse. W. Green & Son, Scotland.

        • Bruggink S.M.
        • Schroeder K.M.
        • Baker-Herman T.L.
        • Schroeder C.A.
        Weight-based volume of injection influences cranial to caudal spread of local anesthetic solution in ultrasound-guided transversus abdominis plane blocks in canine cadavers.
        Vet Surg. 2012; 41: 455-457
      2. Callan RJ, Hackett RP, Fubini SL (2017) Surgery of the swine reproductive system and urinary tract. In: Farm Animal Surgery (2nd edn). Fubini SL, Ducharme NG (eds). Elsevier, USA. pp. 617–632.

        • Castel D.
        • Sabbag I.
        • Meilin S.
        The effect of local/topical analgesics on incisional pain in a pig model.
        J Pain Res. 2017; 10: 2169-2175
      3. Curnutte M (2014) The big problem with mini-pigs. National Geographic Accessed 9 April 2021.

        • de Miguel-Garcia C.
        • Whyte M.
        • St James M.
        • Ferreira T.H.
        Effect of contrast and local anesthetic on dye spread following transversus abdominis plane injection in dog cadavers.
        Vet Anaesth Analg. 2020; 47: 391-395
        • Drożdżyńska M.
        • Monticelli P.
        • Neilson D.
        • Viscasillas J.
        Ultrasound-guided subcostal oblique transversus abdominis plane block in canine cadavers.
        Vet Anaesth Analg. 2017; 44: 183-186
      4. Dyce KM, Sack WO, Wensing, CJG (1996) Textbook of Veterinary Anatomy (2nd edn). Dyce KM , Sack WO , Wensing CJG (eds). Saunders, USA. pp. 789.

      5. Dyce KM, Sack WO, Wensing CJG (2010) Textbook of Veterinary Anatomy (4th edn). Dyce KM , Sack WO , Wensing CJG (eds). Saunders Elsevier, USA. pp. 762.

        • Ekstrand C.
        • Sterning M.
        • Bohman L.
        • Edner A.
        Lumbo-sacral epidural anaesthesia as a complement to dissociative anaesthesia during scrotal herniorrhaphy of livestock pigs in the field.
        Acta Vet Scand. 2015; 57: 33
      6. Evans HE, de Lahunta A (2017) The skeletal and muscular systems. In: Guide to the Dissection of the Dog (8th edn). Evans HE, de Lahunta A (eds). Elsevier, USA. pp. 6–95.

        • Freenan H.T.
        • Newman J.A.
        Rib and vertebral numbers in swine.
        Can J Anim Sci. 1962; 42: 232-239
        • Freitag F.A.V.
        • Muehlbauer E.
        • Gaio T.D.
        • et al.
        Evaluation of injection volumes for the transversus abdominis plane block in dog cadavers: a preliminary trial.
        Vet Anaesth Analg. 2021; 48: 142-146
        • Gutierrez K.
        • Dicks N.
        • Glanzner W.G.
        • et al.
        Efficacy of the porcine species in biomedical research.
        Front Genet. 2015; 6: 293
        • Hamill J.K.
        • Rahiri J.L.
        • Liley A.
        • Hill A.G.
        Rectus sheath and transversus abdominis plane blocks in children: a systematic review and meta-analysis of randomized trials.
        Paediatr Anaesth. 2016; 26: 363-371
        • Harper R.A.
        • Pfeiffer F.M.
        • Choma T.J.
        The minipig as a potential model for pedicle screw fixation: morphometry and mechanics.
        J Orthop Surg Res. 2019; 14: 246
        • Hocking G.
        • Wildsmith J.A.
        Intrathecal drug spread.
        Br J Anaesth. 2004; 93: 568-578
        • Khan S.
        • Cipriano C.
        • Marks J.M.
        • Schomisch S.J.
        Porcine abdominal wall simulator for laparotomy incision and closure.
        Surg Innov. 2015; 22: 426-431
        • Kuls N.
        • Trujanovic R.
        • Otero P.E.
        • Larenza-Menzies M.P.
        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; 90: 102994
        • Manassero A.
        • Bossolasco M.
        • Meineri M.
        • et al.
        Spread patterns and effectiveness for surgery after ultrasound-guided rectus sheath block in adult day-case patients scheduled for umbilical hernia repair.
        J Anaesthesiol Clin Pharmacol. 2015; 31: 349-353
        • Melesse D.Y.
        • Chekol W.B.
        • Tawuye H.Y.
        • et al.
        Assessment of the analgesic effectiveness of rectus sheath block in patients who had emergency midline laparotomy: Prospective observational cohort study.
        Int J Surg Open. 2020; 24: 27-31
        • Michielsen A.J.H.C.
        • Rodrigo-Mocholí D.
        • Cornillie P.
        • et al.
        Description of different ultrasound guided transversus abdominis plane block in pig cadavers – a pilot study.
        Vet Anaesth Analg. 2021; 48: 470-477
        • Mirra A.
        • von Rotz A.
        • Schmidhalter M.
        • et al.
        Ultrasound-guided lateral and subcostal transversus abdominis plane block in calves: a cadaveric study.
        Vet Anaesth Analg. 2018; 45: 384-391
        • Moura E.C.R.M.
        • Honda C.A.O.
        • Bringel R.C.T.
        • et al.
        Minimum effective concentration of bupivacaine in ultrasound-guided femoral nerve block after arthroscopic knee meniscectomy- a randomized, double-blind, controlled trial.
        Pain Physician. 2016; 19: E79-E86
        • Park S.J.
        • Kim H.J.
        • Yang H.M.
        • et al.
        Impact of simulation-based anesthesiology training using an anesthetized porcine model for ultrasound-guided transversus abdominis plane block.
        J Int Med Res. 2020; 48 (300060519896909)
        • Raymond S.A.
        • Steffensen S.C.
        • Gugino L.D.
        • Strichartz G.R.
        The role of length of nerve exposed to local anesthetics in impulse blocking action.
        Anesth Analg. 1989; 68: 563-570
        • Rohrer G.A.
        • Nonneman D.J.
        • Wiedmann R.T.
        • Schneider J.F.
        A study of vertebra number in pigs confirms the association of vertnin and reveals additional QTL.
        BMC Genet. 2015; 16: 129
        • Saller A.M.
        • Werner J.
        • Reiser J.
        • et al.
        Local anesthesia in piglets undergoing castration-a comparative study to investigate the analgesic effects of four local anesthetics on the basis of acute physiological responses and limb movements.
        PLoS One. 2020; 15e0236742
        • Schroeder C.A.
        • Snyder L.B.
        • Tearney C.C.
        • et al.
        Ultrasound-guided transversus abdominis plane block in the dog: an anatomical evaluation.
        Vet Anaesth Analg. 2011; 38: 267-271
        • St James M.
        • Ferreira T.H.
        • Schroeder C.A.
        • et al.
        Ultrasound-guided rectus sheath block: an anatomic study in dog cadavers.
        Vet Anaesth Analg. 2020; 47: 95-102
        • Sviggum H.P.
        • Niesen A.D.
        • Sites B.D.
        • Digler J.A.
        Trunk blocks 101: transversus abdominis plane, ilio-inguinal–iliohypogastric, and rectus sheath blocks.
        Int Anesthesiol Clin. 2012; 50: 74-92
        • Takeda A.
        • Ferraro L.H.
        • Rezende A.H.
        • et al.
        Minimum effective concentration of bupivacaine for axillary brachial plexus block guided by ultrasound.
        Braz J Anesthesiol. 2015; 65: 163-169
        • Uppal V.
        • Sancheti S.
        • Kalagara H.
        Transversus abdominis plane (TAP) and rectus sheath blocks: a technical description and evidence review.
        Curr Anesthesiol Rep. 2019; 9: 479-487
        • Zhang L.C.
        • Liu X.
        • Liang J.
        • et al.
        Quantitative trait loci for the number of vertebrae on Sus scrofa chromosomes 1 and 7 independently influence the numbers of thoracic and lumbar vertebrae in pigs.
        J Integr Agric. 2015; 14: 2027-2033
        • Zhu J.L.
        • Wang X.T.
        • Gong J.
        • et al.
        The combination of transversus abdominis plane block and rectus sheath block reduced postoperative pain after splenectomy: a randomized trial.
        BMC Anesthesiol. 2020; 20: 22
        • Zoff A.
        • Laborda-Vidal P.
        • Mortier J.
        • et al.
        Comparison of the spread of two different volumes of contrast medium when performing ultrasound-guided transversus abdominis plane injection in dog cadavers.
        J Small Anim Pract. 2017; 58: 269-275