Felis ISSN 2398-2950

Anesthesia: peripheral nerve block - pelvic limb

Synonym(s): Peripheral nerve block of the pelvic limb; PNB

Contributor(s): Enzo Vettorato, Luis Campoy

Introduction

  • Local anesthesia Local anesthesia: overview or loco-regional anesthesia Local anesthesia: intravenous regional anesthesia (IVRA) is a technique to induce a reversible absence of sensation (anesthesia) in a defined part of the body (local).
  • Peripheral nerve block (PNB) is the administration of a local anesthetic drug in proximity of a peripheral nerve to inhibit the conduction of the impulse through it.
  • If an adequate amount of a local anesthetic drug is injected in the proximity of a sensory nerve desensitization of the area served by the relevant nerve will occur.
  • If an adequate amount of a local anesthetic drug is injected in the proximity of a motor nerve paralysis will occur.

Uses

  • PNB techniques are used to provide intraoperative anesthesia and, depending on the local anesthetic drug used and the length of the surgery, postoperative analgesia.
  • PNB can be used to provide anesthesia and analgesia and muscle relaxation for both orthopedic and soft tissue surgery of the pelvic limb.

Advantages

  • Cheap and relatively easy to perform.
  • Produce intraoperative antinociception and, depending on drugs used and duration of the surgery, postoperative analgesia.
  • Allow performing surgical procedures under sedation or lighter plane of anesthesia, therefore decreasing the potential cardio-respiratory effects associated with general anesthesia General anesthesia: overview.
  • Might decrease postoperative opioid consumption producing postoperative analgesia.
  • Minimal systemic side effects have been reported, if not overdosed or accidently injected intravenously.
  • Compared to epidural Anesthesia: epidural, PNB allows a more selective blockade, therefore the animal can still be ambulatory on 3 legs during the postoperative period.
  • Reduced risk of urinary retention.

Disadvantages

  • Failure of the block: if the animal is not fully anesthetized it is advisable assessing the quality and the extension of the block using pin-prick technique or hemostatic forceps before starting the surgery.
  • Depending on type of surgery and animal's demeanour the administration of sedative Sedation or sedative protocol or general anesthetic in conjunction with local anesthetic technique might be necessary.
  • Toxic plasma levels of a local anesthetic can produce neurological and cardiovascular signs especially if injected intravenously. Therefore, aspiration before injection is advisable to decrease the risk of accidental intravascular injection.
  • If the animal is sedated, intraoperative movement can occur even if the local anesthetic technique is 100% successful.
  • Epidural spread has been described blocking the nerves within the psoas compartment (lumbar plexus). This might increase the risk of hypotension, therefore monitoring of arterial blood pressure Arterial blood pressure: oscillometric is advisable.

Requirements

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Preparation

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Procedure

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Aftercare

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Haro P, Laredo F, Gil F et al (2013) Ultrasound-guided dorsal approach for femoral nerve blockade in cats: an imaging study. J Feline Med Surg 15 (2), 91-98 PubMed.
  • Portela D, Otero P E, Briganti A et al (2013) Femoral nerve block: a novel psoas compartment lateral pre-iliac approach in dogs. Vet Anaesth Analg 40 (2), 194-204 PubMed.
  • Vettorato E, De Gennaro C, Okushima S et al (2013) Retrospective comparison of two peripheral lumbosacral plexus blocks in dogs undergoing pelvic limb orthopaedic surgery. J Small Anim Pract 54 (12), 630-637 PubMed.
  • Campoy L, Martin-Flores M, Ludders J W et al (2012) Procedural sedation combined with locoregional anesthesia for orthopedic surgery of the pelvic limb in 10 dogs: case series. Vet Anaesth Analg 39 (4), 436-440 PubMed.
  • Campoy L, Martin-Flores M, Ludders J W et al (2012) Comparison of bupivacaine femoral and sciatic nerve block versus bupivacaine and morphine epidural for stifle surgery in dogs. Vet Anaesth Analg 39 (1), 91-98 PubMed.
  • Haro P, Laredo F, Gil F et al (2012) Ultrasound-guided block of the feline sciatic nerve. J Feline Med Surg 14 (8), 545-52 PubMed.
  • Mahler S P (2012) Ultrasound guidance to approach the femoral nerve in the iliopsoas muscle: a preliminary study in the dog. Vet Anaesth Analg 39 (5), 550-554 PubMed.
  • Mahler S P & Adogwa A O (2008) Anatomical and experimental studies of brachial plexus, sciatic, and femoral nerve-location using peripheral nerve stimulation in the dog. Vet Anaesth Analg 35 (1), 80-89 PubMed.
  • Denny N M & Harrop-Griffiths W (2005) Location, location location! Ultrasound imaging in regional anaesthesia. Br J Anaesth 94 (1), 1-3 PubMed.

Other sources of information

  • Campoy L & Mahler S (2013) The pelvic limb. In: Small Animal Locoregional Anesthesia and Analgesia. Wiley-Blackwell.
  • Seco O et al (2013) Ultrasound-guided Peripheral Nerve Blocks. In: Small Animal Locoregional Anesthesia and Analgesia.Wiley-Blackwell.


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