Inflatable retention system for enteral feeding device

An inflatable retention system for an enteral feeding tube having a base deployed outside the human body and an indwelling retainer which is deployed within a lumen of the body by insertion through a stoma from outside the body, the retention system comprising:

• a tube having a proximal end, a distal end, an external tube diameter, and tube walls defining a feeding lumen and an inflation lumen;
• and
• an inflatable balloon located at a distal end of the tube in fluid communication with the inflation lumen, the balloon having thin, flexible walls, each wall ranging from about 5 micrometers to about 100 micrometers in thickness, and a collapsed, non-inflated state such that the tube and the thin, flexible walls of the balloon can pass through an orifice having a diameter not more than about 20 percent greater than the external diameter of the tube, a predetermined spheroid shape, a reserve volume having a lower limit that is greater than 0.5 milliliters of a fluid and an upper limit at a transition between a non-distended state and a distended state of the balloon in which a fluid in the balloon is under no pressure, and a predetermined fill volume about 1.01 to about 1.5 times greater than an upper limit of the reserve volume, such that upon inflation with a fluid to pressurize fluid in the balloon, the balloon assumes a stable spheroid shape and exhibits a substantially linear pressure versus volume curve to at least the predetermined fill volume.