Pulsed carbon dioxide laser for cartilage vaporization and subchondral bone perforation in horses. Part I: Technique and clinical results.

The research article explores the use of a rapidly pulsed carbon dioxide laser for intra-articular use in horses. The study found that the laser vaporizes cartilage effectively but penetrates bone poorly, which potentially limits its application in certain procedures.

Research Method

• The researchers used a lensed 5 mm laser probe attached to a hand-held carbon dioxide laser for this study. This probe was inserted into one intercarpal joint of eight horses, under arthroscopic guidance.
• In four horses, a cartilage crater 1 cm in diameter was created to the level of the subchondral bone of the articular surface of the third carpal bone using the laser.
• In the other four horses, the laser was directed perpendicular to the articular surface of the third carpal bone. The laser was then activated to penetrate the cartilage and subchondral bone.
• The intercarpal joint of the opposite carpus in each horse was subjected to arthroscopic examination and insertion of the laser probe, without activating the laser, for control purposes.

Results and Conclusions

• After eight weeks of clinical evaluation, horses were euthanatized for the examination of the joints radiographically, grossly, and histologically. This allowed researchers to further examine the effect of the laser on cartilage and bone.
• The pulsed carbon dioxide laser vaporized cartilage readily but penetrated bone poorly, indicating a limitation with bone operations.
• Cartilage vaporization did not result in greater swelling, heat, pain on flexion, lameness, or synovial fluid reaction than the control procedure. This suggests the process may not induce any additional adverse side effects compared to regular procedures.
• However, laser drilling resulted in a shallow, charred hole with a tenacious carbon residue. Combined with thermal damage to deeper bone, this led to increased swelling, mild lameness and persistent synovitis.
• In conclusion, the researchers suggest that the carbon dioxide laser is a valuable tool for removal of cartilage, especially in inaccessible regions of diarthrodial joints. However, the data suggests it may not penetrate bone effectively to be useful in subchondral drilling procedures.