Vertical grooving in the treatment of equine laminitis

Introduction

The dorsal wall lifting theory can be summarised as ‘rapid heel growth causing a painful distortion of the dorsal hoof wall’. To test this hypothesis, the heel and toe areas of the hoof wall were separated by a deep grooves on each side of the dorsal wall, this disunited each heel from the dorsal hoof wall. The majority of cases showed a subsequent reduction in pain and this was interpreted as confirmation that early hoof capsule distortion was traumatising the laminae, these results also help support the dorsal wall lifting theory.

Testing the dorsal wall lifting theory

When ‘grooving’ was used to test the dorsal wall lifting theory, over 80% of laminitic animals showed a reduction in pain within fourteen days of being grooved. Both acute and chronic cases benefited from the procedure. This improvement was interpreted as confirmation that hoof distortion was contributing to the pain experienced by the laminitic animals. To date over thirty acute laminitic cases have been grooved, the majority showing a marked improvement within the fourteen-day period. Unfortunately, several of the most severely affected animals failed to respond and were subjected to euthanasia, despite receiving all the other normally accepted veterinary treatments for laminitis.

Over one hundred chronic cases have also been grooved, again approximately 80% showing a general reduction in pain within fourteen days. The procedure was first used in 1998.

Several months after grooving, some grooves can be seen to have visibly closed at their distal border (Fig 2). It is also interesting to note that some chronic laminitic cases became lamer as the top of the groove grew down the hoof, when the top of the groove was extended back up to the coronary band lameness subsided. All these findings are consistent with a model of laminitis based on hoof distortion.

It must be remembered that the grooving procedure is addressing the effects of rapidly heel growth and not removing the cause. With a better understanding of what is taking place during laminitis, more effective methods of controlling hoof distortion may be found.

Dorsal wall resections

Removal of the dorsal wall by dorsal wall resection is well known to give pain relief when sepsis or other fluids are given exit. In many cases a resection fails to reveal any trapped fluids to justify performing the procedure, but many owners will report that the resection provided pain relief to the laminitic animal. The removal of the dorsal wall can be justified using the dorsal wall lifting theory, as a removed dorsal wall can’t exert a lifting force onto the underlying laminae.

Veterinary clinical care

The clinical care of all laminitic horses and ponies is the responsibility of the individual animals veterinary surgeon, grooving should only be performed as part of the veterinary surgeons prescribed regime of treatment.

Grooving procedure

The primary objectives of the grooving procedure are to minimise the painful distortion of the hoof capsule and prevent the progression of the condition. The earlier this can be performed in the acute stage, the sooner the animal will receive pain relief.

Grooves were cut using a very sharp farrier’s drawknife, this was usually well accepted by the animal as the grooving procedure does not directly cause pain (Fig. 3).

Groove positioning

The grooves were positioned medial and lateral to the dorsal hoof surface, approximately midway between the toe and heel regions of the hoof, staring 1cm distal to the coronary band and extending to the ground surface (Fig. 4  x-x). The grooves were cut either in alignment with the horn fibres (Fig. 4 B) or directly downwards (Fig. 4 A). The groove penetrated into the hoof until the non-pigmented epidermal laminae became visible but not deep enough to cause bleeding, although bleeding may sometimes happen. As there is a small risk of making the foot bleed during the insertion of the grooves, it is advisable to tell the owner that this may happen before commencing.

The exact positioning of the grooves depends on how the feet are to be shod afterwards, as it is preferable that the shoe is not nailed on each side of the groove, this effectively reduces the efficiency of the groove. Heart bar shoes require nail positioning towards the heel, therefore the grooves may be placed further forward. If the animal is to be shod with normal shoes the grooves can be positioned just palmer the last nail position.

When trimming the feet prior to shoeing, care must be taken not to lower the heels if there is any indication of a history of upright conformation or flexural deformities.

Styrofoam pads avoid the nailing problem altogether in the short term and offer several other advantages for the acute laminitic (Fig 5). They provide a soft, shock absorbing covering to the foot surface. The pad compress at the toe, leaving the heel raised, this can be useful if there is uncertainty about the involvement of the deep digital flexor tendon. There is also a tendency for the foot to retain moisture under the plastic tape used to hold the Styrofoam pads on the feet, this hydrates the hoof in the grooves, enabling them to close and absorb the changes in hoof shape.

Caution when grooving

Long term chronic laminitic cases may appear as good candidates for the grooving procedure but a great deal of care must be taken in selecting a particular laminitic animal for grooving. If there is any indication of a previous history of upright conformation, flexor tendon involvement (flexural deformity) or previous excessive heel lowering, before the onset of laminitis, then caution should be taken before grooving is undertaken. As these are all indications that this case of laminitis may have been caused mechanically and the dorsal wall may be overloaded, grooving would then concentrate all the horses’ weight onto the dorsal wall, with the grooves preventing the heel laminae carrying any transferred weight from the dorsal wall. Under these circumstances lameness will be intensified by the grooving procedure and it is therefore contraindicated.

Please refer to:- Unilateral Laminitis and remember these long-term cases do not respond well to conventional laminitis therapies and will therefore seem likely candidates for the grooving procedure due to the long-standing nature of their condition.