Gas shadows
The main method of assessing the need for a dorsal
wall resection is by taking radiographs, the presence of a 'gas' shadow will
reveal the presence of a void under the hoof wall. Until the hoof wall
is resected it's impossible to tell what is contained within the gas
shadow. Serum, blood and literally gas can be confined under the hoof
wall, these entrapped products can be extremely painful and prevent the
application of support under the foot until it is relieved.
What ever is found after the resection many equines show a significant
reduction in pain regardless of what is released.
With the vascular
crisis theory when little or no exudate is released after a dorsal wall
resection, it is difficult to
explain why resected feet are less painful, but with the dorsal wall
lifting theory this pain relief can be attributed to the removal of the
extension forced being exerted onto the laminae by the lifting dorsal wall
and the upwards pressure of the sole.
If there is any suspicion of entrapped gas or fluid
under the dorsal wall, it's vital that a resection is preformed,
particularly if a heart bar shoe or similar support shoe is to be
applied to the foot, failing to resection the dorsal wall will intensify
the pressure of the
entrapped fluids and increase the pain levels, this is often
miss-interpreted as the laminitis getting more severe. |