We regularly get cats referred for treatment of fractured jaws after being injured in road traffic accidents. We have been doing at least one of these cases every week for a month or two recently.
Fractures at the front of the lower jaw are usually straightforward to fix with wire or with a wire and a pin. Fractures further back in the jaw can be problematic. The jaw bone gets progressively less accessible the further back you go. The bone is small, it is not flat and it is not straight. There are teeth roots to contend with, and sometimes these fractures are open (bone is exposed). These issues complicate the placement of implants and increase the risk of complications. Luckily fractures at the back of the mouth are well surrounded by muscle and have a good blood supply, so getting them to heal isn’t usually the problem. The problem is getting them to heal straight. If the jaw doesn’t heal straight the teeth can conflict with each other. This is called a malocclusion. A deviated jaw also doesn’t look as nice and probably isn’t as comfortable.
A common approach to fractures at the back of the jaw is to stabilise any accompanying injuries at the front of the jaw, and then to line up the canine teeth in their proper position to achieve an acceptable occlusion. We then temporarily place wire between the upper jaw and the lower jaw to hold the mouth shut for 3 weeks or more while the injury at the back of the mouth heals naturally. Careful adjusting of the wire is required. The wire needs to be tight enough to maintain occlusion, but not so tight that breathing is compromised. These cases have obviously suffered head trauma and the airway through the nose is often less clear than normal. So we usually wait a few days before placing these wires to make the anaesthetic and the procedure as safe as we can make it. Skilled nurses, multiparameter monitoring equipment and supplemental oxygen tents are a huge help!
The wires are usually left protruding through the skin under chin. Although a little disconcerting for the owners this is well tolerated by the patients and has a number of advantages. Firstly it allows drainage of any fluid and debris that would otherwise accumulate as an abscess; secondly the wire twist knot remains stronger and tighter if it is not bent over; and finally, by leaving the wire “proud” we leave ourselves with something to grab when we come to remove it!
If the jaw is temporarily wired shut the patient obviously can’t eat normally. But even if the jaw isn’t wired shut, mouth injuries can stop cats eating normally, and it can be very difficult for owners and stressful for cats to be force fed by syringe.
We often place a feeding tube to allow the pet to receive food and water directly into the stomach via a syringe. One end of the tube sits in the stomach and the other end passes out through the left body wall just behind the ribs. We don’t need to open up the abdomen to place these tubes. Some owners choose to leave animals hospitalised while they are being tube fed. But once owners have been shown how to do this, most find it very simple and easy to do at home. Feeding patients through these tubes takes very little time or effort, but the feeding does need to be done several times a day, so it is something of a commitment.
The feeding tube stays in place at least until the jaw has healed enough to allow the removal of any implants that are obstructing normal ingestion of food. Wire removal usually need s second very short general anaesthetic. Once the animal is feeding normally, the tube feeding can be stopped.
These feeding tubes can be easily be removed a few weeks later when they are no longer needed, usually without a second anaesthetic. They are usually very well tolerated and we have known animals to have these tubes left in situ for many months (for other reasons) while still enjoying otherwise normal and active lives.
11th December 2013