Adjustable surgical sling

A method of implanting a sling assembly comprising:

• implanting a sling assembly under a patient's bladder neck or urethra wherein the sling assembly comprises:
• a urethral support sling having first and second ends and an expandable chamber located intermediate to the first and second ends, the expandable chamber including upper and lower sides wherein:
• the upper side is substantially flat when the expandable chamber is inflated;
• the upper and lower sides are attached at one or more locations internal to the expandable chamber;
• and
• the one ore more locations include at least one through passage forming a perforation through the chamber, the perforation having at least one side wall extending between the upper side and the lower side and defining an external surface of the expandable chamber;
• and
• expanding the chamber.