Venomoids - A Practitioner's View
Reproduced with permission of Raymond Hoser
For more than 20 years, reptile enthusiasts have dreamt of making dangerously venomous snakes harmless.
Several reasons actually.
Besides the obvious one of public safety in that "fixed" snakes could be shown without risk, the desire to render snakes harmless to humans was also sought for the snake's benefit in that they could be effectively "deshackled" from pinning and hooking, both handling methods giving snakes pain, and instead free-handled mid body in the same way harmless snakes usually are, giving the snakes less stress and hence increasing their long-term health and longevity
Fang removal isn't an option as these regrow and so the focus was then on the surgical removal of venom glands.
In recent years and with the aid of modern medical techniques, herpetologists and veterinary surgeons have actually attempted to do this, in that they tried to surgically remove the venom glands and leave the snake alive and intact.
Until early 2004 the operation had been trialled with mixed results in the USA, UK and at least once in Australia. The only reported Australian attempt was by Sydney herpetologist David Millar and resulted in two Tiger snakes dying prematurely and hence was an abject failure.
In the USA where more attempts were done at the operation, the results were somewhat better, some vets reported up to a 50% success rate, in that nearly half the snakes operated on actually survived.
These snakes became known in the trade as "Venomoid". Due to the high mortality of snakes, the procedure was generally regarded as cruel and shunned by most reptile people.
The operation procedure was essentially as follows:
A snake is sedated, usually by gas, such as Isoflurane as this is least problematic in terms of dosage. (Injectable sedatives are unreliable for reptiles and the result is often under or overdose, the former leading to an unsedated reptile and the latter in death).
Once sedated, the snake is laid out on the operating table, usually tied down with stockings, with gas tubed into the windpipe to keep the reptile sedated.
The snake's head is then cut open and the venom glands are removed.
Due to the siting of the glands at the top of the back of the head, this area is cut and then stitched up after the operation to remove the venom glands.
Notwithstanding the best veterinary methods, mortality of snakes tended to be due to sedation mishaps or more commonly due to post-operation infections, as well as a smattering of stress-related matters such as non-feeding leading to a downhill spiral in health until death from secondary infection.
Using lateral thinking, Australian herpetologist Raymond Hoser analysed the venomoid operating procedure as known and tried to eliminate all the known problems likely to cause death.
Most importantly however was the simple realisation that it'd be possible to remove the venom glands by going through the roof of the mouth (including through an intervening wall of muscle tissue) instead of through the top of the skull.
Analysis of (mouth-rot) infections in snakes mouths and their successful treatment by hobbyists with generic antibiotics showed that the snake's mouth had a tremendous ability to heal and at high speed.
This contrasted sharply with the fact that snakes external scales have limited healing ability and are constrained by the shedding cycle which for most snakes usually runs only every two to three months.
This contrasting fact alone is what pointed Raymond Hoser to look seriously at doing a venom gland removal operation by going through the roof of the mouth.
There were other factors favoring the method of going through the roof of the mouth.
Unlike scales on the top or side of the head which would be sunken after an operation, complete with wounds and naturally attract dust, dirt and even coagulated blood at the incision site, the top of the mouth when sutured would naturally not attract these things.
Being inside the mouth, the wound would in effect be protected from environmental dusts and hazards. Being on the roof of the mouth, the pus and other debris would naturally drain away from the wound and down the throat or out of the sides of the mouth.
The net result of course would be a self-cleaning wound.
However the idea of operating on the roof of the mouth (cutting it) was unusual in snake surgery in that it presented a new logistical problem in terms of sedation.
The method of choice (gas) was no longer viable. In virtually all other reptile operations, the sedation means (gas and/or tube) is not in the way of where the cutting is being done. However in the planned operation, the snake would have to have it's head affixed to the surface upside down (to yield the area to be cut) and the tube of gas would have to move into the air and bend downwards (in a virtual right-angle) in order to run down the windpipe which sits at the base of the rear of the mouth.
The logistics got worse when it is realised that the mouth would also have to be held open by some means.
To make things worse, this tube would run over the general area to be cut; the venom glands being sited literally to either side of the tube and within millimeters, making cutting problematic, especially as the flesh is parted to yield the tubular venom glands.
As a result of this technical difficulty and general inertia at trying new things, the idea of venom gland removal by going through the roof of the mouth had until 2004 been rejected by herpetologists and veterinary surgeons and had not been tried previously.
This did not however dissuade Raymond Hoser from trying to deal with the other technical issues facing the idea of internal cutting to remove the venom glands.