Veterinary Anesthesia & Analgesia Support Group
Practical Information for the Compassionate Veterinary Practitioner
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Intratesticular Blocks


1)     Intratesticular blocks

a)      This is a very effective, low-cost application of local anesthetic agents

b)      Mix 1.0 mg/kg bupivacaine with 1.0 mg/kg lidocaine as your base

i)        Adding a mu agonist opioid has been shown to effectively double the duration of analgesia

ii)       Opioid options include 0.075 mg/kg morphine, 0.015 mg/kg hydromorphone, and 0.003 mg/kg buprenorphine

c)      Use a 25g or 27g 5/8” needle for most cats and a 22g 1 to 1 ½“ needle for dogs

d)      Place the needle through the testicle starting from the caudal pole aiming for the spermatic cord

e)      It is OK, even desirable, for the needle to exit the testicle proximally as it is the spermatic cord that will receive the direct clamp stimulation


i)        Inject, expecting firm backpressure, while withdrawing the needle

ii)      Expect to use about 1/3 to 1/2 of the drug volume per testicle leaving the organ firmly turgid

g)      Repeat for other testicle

h)      The left over drug can/should be used to place a dermal incisional block

i)       The total time for this procedure should be 1 to 2 minutes

j)       Drugs costs (lidocaine + bupivacaine):

i)        3 kg cat = $0.09

ii)      25 kg dog = $0.71

k)      Drugs costs (lidocaine + bupivacaine + hydromorphone):

i)        3 kg cat = $0.11

ii)      25 kg dog = $0.84


IT block in 16 kg canine Incisional block in 16 kg canine
IT block in mature cat
Click on the pictures to play the video. Note aspiration before injection.
These are large files - be patient.
Page areferences:
1 Buprenorphine added to the local anesthetic for axillary brachial plexus block prolongs postoperative analgesia. Candido KD, Winnie AP, Ghaleb AH, Fattouh MW, Franco CD: Reg Anesth Pain Med. 2002 Mar-Apr;27(2):162-7 
2 The addition of opioids to local anaesthetics in brachial plexus block: the comparative effects of morphine, buprenorphine and sufentanil. Bazin JE, Massoni C, Bruelle P, Fenies V, Groslier D, Schoeffler P: Anaesthesia. 1997 Sep;52(9):858-62
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Last modified: September 10, 2011 .