• Coccygeal epidurals for feline urethral obstruction (FUO)

    Feline urethral obstruction

    (FUO) is a common emergency condition seen in feline medicine.  This disease is not only life-threatening, but can be painful as well.  Once the acute obstruction has been relieved, the focus is often shifted to pain management to help reduce urethral spasm.  In this VetGirl podcast, we evaluate the use of a new pain management technique –  coccygeal epidurals – and how this easy to perform technique may benefit cats with FUO. For more information, check out our epidural video, where we walk through the steps of what you need and how to perform an epidural.

Here, a step-by-step approach:

• First, use a 2% preservative-free lidocaine at a dose of 0.1-0.2 mL/kg. This must be a sterile bottle. O’Hearn et al strongly suggested the use of preservative free lidocaine as the local anesthetic. If you don’t have this, you can use lidocaine that contains a preservative – provided it’s a new, unopened, sterile vial; this is b/c we’re only using a small volume and b/c we’re administering it in a caudal location.

• Sedate your cat. Once sedated, the patient is placed in ventral recumbency and the sacrococcygeal region surgically prepped. The injection site can be found by palpating the space between the sacrum and first coccygeal vertebra, which can be palpated as it moves when the tail is moved. Draping is not required and may interfere with the procedure, but aseptic technique is imperative!










Photo courtesy of Dr. Alex Molldrem

• After donning sterile gloves, the injection site is located just cranial to the first coccygeal vertebrae. Alternatively, the first or second coccygeal intervertebral space can be used. To facilitate this step, the tail can be manipulated by an assistant.

• A 25 gauge, 1 inch needle is inserted at a 30 to 45° angle at the midline of the sacro-coccygeal space (which is identified with the index finger of the other hand). While advancing the needle, a characteristic “pop” can be felt. This occurs as the needle penetrates the ligamentum flavum.










Photo courtesy of Dr. Alex Molldrem

• After entering the epidural space, a syringe is attached and gentle negative pressure applied. If blood or cerebrospinal fluid is obtained, the procedure needs to be started again.

• If no blood or any other fluid is aspirated, proceed to infuse the calculated volume into the epidural space. No resistance to injection should be noticed. Inappropriate infiltration into the subcutaneous tissue may create resistance. Voila – all done! The needle is removed after injection.

• You can tell if your epidural is working if you notice relaxation of the tail and rectum; also, pinching of the tail should not produce a response. If a pain response is elicited after 5 minutes of the first injection, a second injection can be attempted. Due to the increase risk of complications, no more than 2 attempts are recommended.

• Urethral de-obstruction can be performed after the lidocaine block has taken effect (which occurs within just minutes)

And with that, you just performed a coccygeal block, providing analgesia to the perineal region for approximately 1 hour. Don’t forget to follow up with additional analgesic therapy (e.g., buprenorphine 11-22 mcg/kg, IV q 6).

OHearn AK, Wright BD. Coccygeal epidural with local anesthetic for catheterization and pain management in the treatment of feline urethral obstruction. JVECC 2011;21(1):50-21.

  1. Pingback: How to perform a coccygeal block | VetGirl Vet CE Video

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