Disc Fenestration in Cats

Disc disease is less common in the cat than the dog, and occurs rarely. 

Pressure from a bulging disc presses on the spinal cord resulting in pain, and in the worst cases, paralysis. There are a number of different surgical techniques used to treat disc disease, of which fenestration is the most straightforward. 

Discus fenestration is a technique whereby the surgeon makes a small opening or 'window' through the fibrous outer ring (annulus fibrosus) of the disc, in order to remove the gel-like central core (nucleus pulposus). 

This is a preventative procedure to reduce the risk of disc prolapse in patients with a known risk. 

Disc fenestration does not need special equipment but is a highly skilled procedure. Experienced surgeons in first opinion practice may be comfortable performing this operation or alternatively referral to a specialist may be preferred. 

An MRI or CT scan help localize troublesome discs. The patient is given a full general anesthetic, the hair clipped along the area of interest and the skin aseptically prepared. 

The surgeon makes a long skin incision running parallel to the spine. Then the musculature overlying the spine is gently dissected away to give good visualization of the disc. A burr is used to drill into the disc material and give the gel-like core a way out that doesn't impinge on the spinal cord. 

This is repeated for every disc in the area of interest, such as the neck, or lower back. 

It is a reasonable assumption that if one or two discs have already herniated, then others may follow. More complex surgery may be need, such as a hemi-laminectomy, for those discs which have already herniated, and then fenestration performed on the neighboring discs as a preventative measure. 

Disc fenestration removes the core of the disc, and therefore removes a future hotspot of trouble. It is an extremely effective procedure when performed successfully.

It is essential that the cat rests for a period of time following surgery. The clinician will supply a bespoke physiotherapy routine with passive exercises to help maintain muscle tone. Some cats require disc surgery to decompress the spine and attempt to reverse paralysis. In these cats, any improvement or return of nerve function is likely to be slow. In these patients, a urinary catheter may be placed in order to empty the bladder comfortably, and antibiotic provided because of an increased risk of urinary infections. 

The cat must not lick the sutures, and must wear a T-shirt or cone to protect the incision. Skin sutures are removed after 10 to 14 days and the rehabilitation program continued for as long as necessary. 

Disc surgery requires careful planning, using sophisticated imaging to locate the trouble spots. An MRI or CT scan comes in around $1,000 to 1,500. The cost of surgery itself is likely to be around $2,000 upwards. 

As with any surgery there are risks involved. These include incomplete removal of the disc material and accidental injury to the spinal cord during the procedure. In the worst case scenario this could lead to partial or complete paralysis of the region supplied by those nerves.

Once performed, the beneficial effects are permanent. 

Disc fenestration is major surgery. In cats with back pain due to disc disease, it is appropriate to try medical therapy and rest first, in all but the most severely affected. Pain killing medication can help reduce muscle spasm, which in turn reduces the compressive forces on vertebrae which are squeezing on the disc. 

It may be that inherited factors predispose some cats to disc disease. Therefore, cats who have suffered from episodes of disc disease should not be bred from.