Brachial Plexus Exploration in Cats

The brachial plexus is the main nerve 'junction box' to the forelimb. Nerve related problems such as numbness or loss of function in a front leg are possible indications for checking the integrity of the brachial plexus. However, exploration of the brachial plexus in the cat is a little used technique to directly visualize the brachial plexus and check it for injury or cancer. 

The most common problem is usually traumatic, often with a closed injury (ie. the skin is not broken) when the cat's front leg gets pulled forcibly away from the body. Alternatively, cancer of the brachial plexus may be suspected. In both situations, advanced imaging techniques such as an MRI scan should give the clinician the relevant information and more. Thus open exploration has been largely superseded or is reserved for cases where forelimb amputation is likely to be needed anyway. 

The cat is given a full general anesthetic. The fur in the region of the armpit, forearm, and chest wall is clipped and the skin scrubbed. Under aseptic conditions, the surgeon makes a curved incision in the axillae, corresponding to the location of the brachial plexus. 

The plexus itself is a web-like arrangement of nerves threading into the deeper muscles, and it is time-consuming and delicate work to follow all the nerves. The surgeon is alert for signs of pathology such as swelling (that could indicate inflammation or cancer) or broken nerve roots. 

If lacerated nerves are located, an attempt to repair them may be made. The surgical site is then closed and the cat woken from the anesthetic. 

Even in human medicine, the role of brachial plexus exploration is controversial. This is because spontaneous nerve repair may take place, so in the rare cases where nerves are surgically repaired, it is hard to know if the patient might have recovered anyway. 

Recovery from anesthesia should be uneventful. The cat has skin sutures in place for 10 to 14 days. 

Brachial plexus exploration would be done by a specialist veterinary consultant in neurology. As such, the cost of the initial consultation is around $200. The surgery itself is time-consuming and an invoice for $1,500 to $2,000 is to be expected. 

The cost of an MRI scan varies depending on the veterinary center, but expect to pay $600 to $1,700.

Modern imaging techniques such as MRI scans have largely superseded the need for direct visualization of the brachial plexus. Indeed, imaging provides superior access as the nerves can be followed deep into the muscles, giving extra information above what can be seen with the naked eye. 

Surgical exploration would be beneficial if there was a surgical option for repair. But even under these circumstances there is a strong argument for a MRI scan to plan the surgery, thus making the exploration part redundant. 

The commonest cause of brachial plexus avulsion is a cat that does the splits on a slippery floor, trauma to the forelimb (such as a traffic accident), or cruelty. Sensible precautions such as carpeting floors and supervising cats whilst outdoors help protect a cat from physical injury.