The diagnostic nerve block of the sesamoidean nerve: desensitized structures and possible clinical applications.

The research article discusses a technique developed to block the sesamoidean nerve, a branch of the palmar nerve, which controls sensations in the proximal sesamoid bone and nearby regions. This was tested on ponies and horses experiencing lameness to determine what structures are affected and the potential clinical applications of this technique.

Study Design and Methods

• The researchers studied the sesamoidean nerve in horses, which branches from the palmar nerve and leads to the proximal sesamoid bone.
• To understand what structures this nerve innervates, a technique to block the nerve was developed and tested in different cases of pony and horse lameness.
• They observed the effects of this nerve block in ponies with an artificially induced lameness, located either in the lateral proximal sesamoid bone or in the lower part of the lateral branch of the suspensory ligament.
• Additionally, they assessed its effectiveness in horses suffering from sesamoidosis, a common disorder affecting the sesamoid bones.

Findings and Observations

• The study found that lameness caused by inserting an artificial expansion plug into the proximal sesamoid bone could be significantly reduced through the use of a sesamoidean nerve block.
• However, the technique only partially alleviated lameness caused by localized tendonitis in the lateral branch of the suspensory ligament.
• In horses with sesamoidosis, lameness improved by an average of approximately 30% after the nerve block was implemented.

Conclusions and Clinical Applications

• The study concluded that the sesamoidean nerve contains sensory fibers that control the proximal sesamoid bone. Therefore, blocking this nerve can help alleviate pain specifically originating from this bone or its adjacent areas.
• The sesamoidean nerve block was not significantly effective for horses with sesamoidosis, suggesting that the main source of pain in these cases is likely not located in the proximal sesamoid bone.
• Despite this, the specificity of the sesamoidean nerve block makes it a useful technique for determining the specific location of lameness in the fetlock area of a horse. Thus, it has potential clinical applications in diagnosing and treating lameness conditions.