Clear criteria needed for treating severe laminitis
By ANDREW POYNTON FWCF
When not to proceed with
Where it is obvious that there is
irreparable damage within the hoof, patient welfare is such that it is inhumane to
continue to proceed such as devastating total hoof sloughing and gangrene.
If the horse has a metabolic condition that is erratic and untreatable, no amount
treatment is going to resolve the condition; also in geriatric meltdown where the
horse’s organs are failing.
The importance of radiography for accurate diagnosis, prognosis and treatment is
essential. In the acute and post-acute laminitic, only x-ray will reveal what is
happening internally before the external signs become full-blown, such as solar prolapse
or a depression developing at the
coronary border. Precisely how much P3 movement has occurred needs to be known.
Latero-medial radiographs are predominantly most important. Dorso-palmer images can
be useful also, as optimum foot balance is even more critical in laminitic case.
When working from X-ray, the farrier
needs to take reference of the
original dimensions of the hoof in relation to the phalanges, take measurements and
put markers or reference points on the hoof before cutting, otherwise accurate trimming
will not be possible.
So long as the outline of the hoof and bones are visible, measurements and reference
can be taken from them. If the X-ray images have been enlarged or reduced it is helpful
to be informed of what ratio it is, ideally 1:1 actual size.
To identify abnormality, first normality should be studied.
Abnormality is noticed as divergent faces of P3 and the vertical face of the dorsal
hoof wall and the distal tip of P3 closer to the sole (rotation).
Phalangeal rotation is recognised by P3 angle greater than P2 and divergent from
the hoof wall.
Capsular rotation is recognised where the dorsal wall deviates but the phalangeal
alignment remains straight; this is less severe than phalangeal rotation.
Increased distance between the wall and P3 combined with a reduction of distance
between the base of P3 and the sole where greater detachment of the lamella bond
has occurred is recognised as distal displacement
often described as ‘sinking’. Latero- medial displacement is also common.
These descriptions are not mutually
exclusive but are combined in many clinical cases.
More severe cases may reveal any of the following: perforated soles, P3 protruding,
the proximal border of the hoof wall jamming against the extensor process, greater
between P3 and the wall and below P3 and the sole, which may be seromas or sites
of infection, seen as dark pockets on x-ray.
At the coronary border, lesions detaching the hoof from the coronary corium; this
can be partial or in some cases extending from heel
to heel, such cases are usually terminal and about to slough (lose) the hoof.
A clear x-ray of this will show a dark line at the coronary border and a crumpled
step at this juncture along with P3 unusually deep in the hoof.
Recovery or euthanasia:
This can be quite a rollercoaster ride. Some horses that suffer a devastating onset
and severe rotation or sinking, will develop deep seated infections, sole prolapse
and rapid disintegration of the hoof.
This is the turning point one way or the other. Either the infection and pain can
be managed and they recover or this is the point that treatment is terminated and
euthanasia is implemented.
Unnecessary hoof removal can reduce the horse’s chance of recovery.
Anything that is undermined, dead or detrimental needs removal, as and when, is down
to the experience of the practitioners involved.
Relevance of size and weight:
Miniature Shetlands that succumb to laminitis have a small cube of a hoof; their
bones may rotate within the hoof but seldom descend through the soles.
The physical weight of the pony is not adequate to punch a hole through the sole;
proportionately they have a thick, strong sole in ratio to their size compared to
a large warmblood or draught horse; these ponies are relatively easy to treat.
However, when it comes to the large warmblood draught horse, or very fat cob, they
are more difficult to manage.
Why might this be?
I believe if it was more fully understood that the weight of the horse bearing down
through the bone column is the major destructive force following laminal breakdown,
and if P3 descent is to have the best chance of being arrested, it needs firm neutralising
resistance from below, from the earliest time possible.
If this approach was broadly adopted I wonder if more large laminitics would be viewed
with more optimism.
WHEN considering treating severe laminitic cases, there needs to be clear criteria
for proceeding and initially a tripartite agreement on the way forward is desirable.
The veterinary surgeon, farrier and owner should discuss the level of commitment
in time, care and finance and agree to work together; without this, it is futile
proceeding. Is there light at the end of the tunnel? What is a realistic prognosis?
In considering this, it is worth adhering to the basic sentiment of the Hippocratic
Oath to ‘never do harm’.
The first and most important factor is the welfare of the patient.
Is the pain manageable? Is there infection that can be managed and are there still
adequate signs of life to reinstate recovery, whether it is full or partial?
This is dependent on good blood supply and freedom from physical constriction.
What and when are the signs? There must be potential of new growth from the coronary
border of the hoof.
If a collar of horn can regenerate from heel to heel, then there is potential for
new hoof growth.
If there is brief break in horn growth and a fault between old and new horn, the
new hoof growth often recovers very well.
Even chronic cases with prolonged constriction to the horn, producing papillae of
the coronary corium may recover if trimmed sympathetically, but some endure stunted
and permanently deformed growth.
These cases can be treated to maintain paddock soundness for a valuable brood mare
only whilst hoof reconstruction and remedial support shoeing is maintained.
In the first of a two-part feature on the treatment of severe laminitics, Andrew
Poynton FWCF of Poynton Ltd, discusses the parameters for commencing treatment.
A foot with the greater part of the hoof sloughed, within a month of treatment commencing.
The same foot recovering five weeks later
Shows a severe case of rotation
Foot 13 months after start of treatment, 12 months after the first picture (top)
This article first appeared in Horse Health Magazine, May/ June 2010