“…26,27 Other studies used other types of tubes: Putterman-Gladstone tube in 6 studies 11,17,23,28,41,45 ; silicone or polythene tubes in 6 studies 30,35,38,47,50,52 ; 3 studies used mucus membrane techniques. 32,49,54 Endoscopy-assisted approach Twenty-one (39%) studies 5,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] reported using a nasal endoscope or a combination of a non-endoscopy-assisted and endoscopy-assisted approach during the procedure. All these studies used Pyrex tubes and were published from 2000 onward.…”