TECHNIQUE

Caudal Epidural Anaesthesia of Cattle 

Summary Information
Type of technique Health & Management / Ruminants Pain Management / INDIVIDUAL Technique:
Synonyms and Keywords --
Description Caudal epidural anaesthesia involves injection of local anaesthetic and/or other appropriate drugs into the epidural space at the sacro-coccygeal or first intercoccygeal junction in order to produce analgesia of the tail, perineum, genitalia and pelvic viscera. (B342.16.w16) 

"Providing that the concentration of the solution used is sufficient to paralyse the sensory fibres, skin analgesia will develop in the tail and croup as far as the mid-sacral region, the anus, vulva and perineum and the posterior aspect of the thighs. Paralysis of motor fibres will cause the anal sphincter to relax and the posterior part of the rectum to balloon. Defecation will be suspended, stretching of the vulva will produce no response and the vagina will dilate. During parturition straining ceases but uterine contractions are uninfluenced." (B205.12.w12)

  • Locate the first intercoccygeal space by either:
    • Raising and lowering the tail and palpating the depression and movement between the first and second coccygeal vertebrae: the first intercoccygeal space is the first obvious articulation caudal to the sacrum. (B205.12.w12, B342.16.w16); or
    • Standing to one side of the animal, along the line of the croup observe the prominence of the sacrum and caudal to this the next prominence which is the spine of the first coccygeal vertebra; the first intervertebral space is the depression immediately behind this prominence. (B205.12.w12); or
    • Palpate the caudal prominence of the tuberosity of the ischium and move about 10-11 cm forwards in a medium sized cow. A line drawn over the animal at this point will pass through the depression between the first and second coccygeal spines. (B205.12.w12)
  • Disinfect the skin over the first intercoccygeal space. (B342.16.w16)
  • Inject a small amount of local anaesthetic to desensitise the skin over the injection site and minimise reaction during insertion of the needle. (B205.12.w12, B342.16.w16, J234.12.w2)
  • Directly over the midline insert a 3.75 to 5cm long 18 gauge needle, directed at about 10 degrees to the vertical (right angles to the general plane of the croup), over the first intercoccygeal space. (B342.16.w16)
    • At about 15 degrees to the vertical, advancing the needle ventrally and cranially until the needle touches the floor of the spinal canal. (B205.12.w12)
      • Be prepared for sudden movement of the animal which may occur if the needle touches a cranial nerve. (B205.12.w12)
    • A 5 cm 18 gauge spinal needle with stylet may be used to avoid potential plugging of the needle with tissue which may then be transferred to the spinal canal on injection. (J234.12.w2)
  • When the needle contacts the floor of the vertebral canal, withdraw about 0.5 cm; the needle tip should then be in the epidural space of the neural canal. (B342.16.w16, J234.12.w2)
  • Aspiration of a few drops of anaesthetic solution from the hub into the needle (hanging drop technique), and minimal resistance to injection indicate correct placement. (B342.16.w16)
    • Suction with a syringe will not produce CSF or blood when the needle is placed correctly. J234.12.w2
    • Injection of 1 ml of air may be used to confirm low resistance to injection. (J234.12.w2)
  • Connect the syringe and inject slowly: 15 ml should take about 10-15 seconds. (B205.12.w12)
    • If attempted injection is met with resistance due to penetration of the needle into the intervertebral disc, withdraw slightly and attempt injection again. (B205.12.w12)
    • If blood appears at the needle hub due to penetration of a vein it should still be possible to make the injection, or the needle may be withdrawn, cleaned of blood clot and reinserted. (B205.12.w12)
  • 1.0 ml of 2% lidocaine hydrochloride per 100 kg bodyweight should produce anaesthesia extending cranially to the middle of the sacrum and ventrally over the perineum to the inner aspect of the thigh, without affecting hind limb motor coordination. (B342.16.w16, J234.12.w2)
    • Five to 10ml of 2% lidocaine (depending on the size of the animal) provides sensory analgesia
    • 2-3 ml of 2% lidocaine or 1.5-2ml of 3% is sufficient in a small cow. (B344.66.w66)
    • 2 ml of 2% plain lidocaine (no adrenaline) for a 75 kg ewe provides about two hours of anaesthesia of the perineal area and posterior reproductive tract. (J15.21.w4)
  • Onset of paralysis of the tail 60 to 90 seconds after injection confirms correct injection. (B205.12.w12). With 2% lidocaine analgesia persists for about 60 minutes with complete recovery after two hours (B342.16.w16); the effects may last for 30 to 150 minutes (B342.16.w16)
  • Maximum analgesia is reached after 5 to 10 minutes using 2% lidocaine (B205.12.w12); after 10 -20 minutes. (B342.16.w16)
    • If lidocaine with adrenaline (0.0125 ml of 1:80,000 adrenaline per ml of 2% lidocaine) is used, tail tone and motility are suppressed for more than 60 minutes. (B342.16.w16)

Alternative drugs:

  • Xylazine 0.05 mg/kg. Inject after diluting to 5ml in 0.9% saline. Provides analgesia of the perineum and reduces straining during parturition. (B205.12.w12)
    • Analgesia develops by 20 minutes after injection and lasts for about two hours. (B205.12.w12)
    • Tail is flaccid, mild ataxia may occur. (B205.12.w12)
    • Also mild sedation, decreased ruminal motility (therefore bloat), bradycardia and decreased mean arterial pressure, due to some systemic absorption. (B205.12.w12)
  • Medetomidine 0.015 mg/kg diluted to 5ml in 0.9% saline. (B205.12.w12)
    • Analgesia induced within 10 minutes and lasting for 412 +/-156 minutes (mean and standard deviation).
    • Mild to moderate sedation and mild ataxia due to some systemic absorption. (B205.12.w12)
  • Combined lidocaine and xylazine. 2% lidocaine at 0.22 mg/kg together with 10% xylazine at 0.05 mg/kg, combined into a total volume of 5.7 ml per 500 kg bodyweight, produced analgesia from the coccyx to T13, with faster onset than administration of xylazine (0.05 mg/kg) alone and longer lasting than lidocaine (0.22 mg/kg) alone. Onset of analgesia was at 5.1 +/- 0.9 minutes (mean +/SEM) which was not significantly different from the time for lidocaine alone (4.8 +/- 1.0 min) and lasted for 302.8 +/- 11 min, significantly longer than that for lidocaine 81.8 +/- 11.8 min or xylazine (252.9 +/- 18.9 min). Mild to moderate sedation and ataxia was noted with the drug combination. (J290.29.w1)

Continuous caudal epidural anaesthesia:

This technique involves placement of an epidural catheter for intermittent administration of local anaesthesia. It may be used in individuals with chronic rectal and vaginal prolapses (J234.12.w2)

  • The catheter is placed into the epidural space using a Tuohy needle 
  • Insert a 5 cm 17 gauge spinal needle (Tuohy needle) with the bevel directed craniad. (J234.12.w2)
  • Remove the stylet and inject 2 ml lidocaine solution to confirm that the tip is placed in the epidural space. (J234.12.w2)
  • Insert the catheter through the needle and advance 2-4 cm beyond the tip of the needle. (J234.12.w2)
  • Withdraw the needle leaving the catheter in place. (J234.12.w2)
  • Secure the catheter in position using adhesive tape sutured to the skin. (J234.12.w2)
  • The free catheter end must be protected to ensure that injections into the catheter will be sterile; for example the catheter may be capped and then wrapped in sterile gauze. (J234.12.w2)
  • Local analgesic solution is injected whenever the animal shows signs that sensation to the blocked region is returning, or at 2-4 hour intervals . (J234.12.w2)
Appropriate Use (?)
  • Used routinely for suturing tears in the perineum or vulva, perineal reconstruction, retraction of the uterine cervix, reduction of uterine prolapse, embryotomy etc. (B342.16.w16)
  • Adjunctive treatment in control of tenesmus associate with perineal, anal, rectal or vaginal irritation. (B342.16.w16)
  • "Provides excellent perineal analgesia and muscle relaxation, minimal cardiovascular and respiratory effects, and rapid recovery." (J234.12.w2)
  • Xylazine 0.05 mg/kg. Inject after diluting to 5ml in 0.9% saline. Provides analgesia of the perineum and reduces straining during parturition. (B205.12.w12)
    • Provides bilateral analgesia of dermatomes supplied by the caudal, caudal rectal, perineal, pudendal and caudal cutaneous femoral nerves. (B205.12.w12)
Notes
  • Strict asepsis must be employed when this technique is used. (B121.20.w20)
  • The level to which anaesthesia is produced depends on the total dose of local anaesthetic agent injected. (B342.16.w16)
  • With correct dosing, hind limb locomotor function and uterine motility are unaffected. (B342.16.w16)
Complications/ Limitations / Risk
  • Rare complications include postural instability, recumbency, haemorrhage if a venous sinus is punctured and infection if sterility is not maintained during the procedure. (J234.12.w2)
  • There is a risk of hindlimb ataxia if an epidural is used, which may increase the risk of the ewe accidentally smothering her lambs, or require the lambs to be removed temporarily. (J15.22.w2)
  • Infection of the epidural space has occurred in cattle following caudal epidural block, although only rarely. (B121.20.w20)
  • Doses greater than 10 ml of 2% lidocaine in cattle (of approximately 450 kg bodyweight) may result in hindlimb incoordination and recumbency. (J234.12.w2)
  • Preparations containing adrenaline (epinephrine) are not suitable for intra-articular, intravenous, epidural or intradigital administration. (B340.6.w6)
Equipment / Chemicals required and Suppliers
  • Disinfectant for skin preparation.
  • 2.5 cm, 25 gauge needle for skin analgesia.
  • Needle for injection into epidural space: 
    • 5 cm, 18 gauge spinal needle with stylet. (J234.12.w2)
    • 3.75 to 5cm long, 18 gauge needle. (B342.16.w16)
Expertise level / Ease of Use Procedure should only be undertaken by an individual with appropriate clinical training and practical experience; this would usually be a veterinarian or someone with advanced veterinary technician training.
  • Relatively simple. (B342.16.w16)
Cost/ Availability
  • Inexpensive; no sophisticated equipment is required. (B342.16.w16, J234.12.w2)
Legal and Ethical Considerations In some countries there may be legislation restricting the use of this type of technique to licensed veterinarians. For example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides, subject to a number of exceptions, that only registered members of the Royal College of Veterinary Surgeons may practice veterinary surgery." (see: LCofC1 - RCVS Guide to Professional Conduct 2000 - Treatment of Animals by Non-Veterinary Surgeons).).
Author Dr Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Graham Bilbrough MA, VetMB, CertVA, MRCVS (V.w69)
References B205.12.w12, B121.20.w20, B342.16.w16, B344.66.w66, J15.21.w4, J234.12.w2, LCofC1 

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