Triangle Tip-Jet Knife used as "probe mode" can reduce the risk of mucosal damage during incision and tunneling phase of POEM procedures.

Peroral endoscopic myotomy (POEM) is a minimally invasive endoscopic technique for the treatment of achalasia and its use has been widely spread in recent years1,2. The Triangle Tip-Jet (TTJ) (Olympus Triangle TipKnife-J, KD645L) has become very popular in this field and currently one of the most used knives for POEM procedures. It has the capability of knife dissection along with submucosal injection and its triangle tip shape is especially useful for pulling tissue during the myotomy phase. However, its length may be too long in situations such as tight esophagogastric junction (EGJ), narrow submucosa due to fibrosis, trimming after mucosal incision and/or less experienced endoscopists3 in which preserving the integrity of the mucosa is vitally important. Distal attachment conical caps like ST Hood (DH28GR,29CR; Fujifilm, Tokyo, Japan) are commonly used for POEM, resting the distal end of the TTJ on the cap, with only the triangular tip protruding. By using straight caps, you can get a wider view and greater maneuverability, however is more difficult to calculate the distance between the triangle tip and the distal attachment end due to its straight shape. The T-shape of the distal TTJ tip was designed for its use in an open position. In this way, while using straight caps and/or less experiences endoscopists during challenging procedures (tight EGJ, submucosal fibrosis) can make them feel unsafe during incision and/or tunneling phase. Herein, we suggest the use of the TTJ knife in "probe mode"4 to reduce the distal knife length from 4.5 mm to 0.3 mm, thus allowing a greater control of the knife tip (Fig 2). In addition, the TTJ probe mode can be safely used with both contact and non-contact currents, which are becoming increasingly popular in recent years.