Concerns have emerged that epidural catheters may cause tattoo pigment to enter interspinous ligaments and other areas, potentially leading to health problems. There is consensus that epidural catheters should not be placed through irritated or infected tattoos. However, harm has not been clearly documented when placing epidural catheters through healthy tattooed skin; a review in the American Association of Nurse Anesthetists Journal concluded that "epidural catheter placement through lumbar tattoos is a practitioner's decision based on clinical judgment".[9] In Current Opinion in Anesthesiology, Frédéric J. Mercier and Marie-Pierre Bonnet state that the evidence for complications when placing epidural catheters is unconvincing, but advocate avoiding the practice owing to the lack of long-term evidence.[10]