Unpinch the symptomatic pincer nail

Many a pincer nail can reside relatively unnoticed, curled in a nail bed and requiring no treatment, but when such nails become symptomatic, surgical treatment is necessary with a main goal of targeting the widened nail matrix, according to Nathaniel J. Jellinek, M.D., a dermatologist at Rhode Island Hospital, Providence.

Pincer nails are nails that have become deformed with an increased, transverse over-curvature, with causes ranging from fungal disease or psoriasis, medications such as beta-blockers, or tumors or cysts.

Most commonly, however, particularly in toenails, the causes are biomechanical or arthritic changes. In such cases, the distal phalanx develops a lateral bone spur that widens the distal portion of the phalanx. This causes the nail matrix to widen and the nail becomes too wide for the nail bed.

Instead, the underlying problems should be treated. If the cause is a fungal infection, an antifungal medication should be used; if it is psoriasis, psoriasis medication should be used; and if it is a tumor, the tumor should be addressed.

For the biomechanical or arthritic causes, surgical treatment offers an effective and permanent resolution. However, since surgery on the lateral bone can carry the risk of injuring a lateral ligament, Dr. Jellinek recommends the surgical approach of narrowing the nail matrix.

The approach involves using a local anesthetic and distal wing block and then taking off one sixth of the plate with a nail splitter in order to isolate the affected side. Dr. Jellinek removes both sides if the pincer is bilateral, or one side if it is unilateral.

Using 90 percent phenol in three cycles of 60 seconds each, Dr. Jellinek then performs a partial matrixectomy that addresses the widening nail growth center, and depending on how affected the nail bed is, lateral nail folds may also need to be repaired. Occasionally, the distal phalanx shows a dorsal osteophyte, which may be rongeured.

Making sure to remove all of the lateral matrix is of particular importance, Dr. Jellinek says.

"It's important to eradicate the entire lateral matrix horn, because if you leave a remnant, patients may recur with a cyst post-operatively," he says.

To do so, he uses a normal, cotton-tipped applicator for two cycles, followed by a small, foam-tipped applicator designed for inner ear procedures to target the final remnants of the nail matrix.

"The surgery is minimally invasive and, in my experience, people usually do quite well and with a good result post-operatively," Dr. Jellinek says.