Medical devices and related methods for the treatment of spinal conditions are described herein. In one embodiment, a method includes disposing at least a portion of a support member into a space between adjacent spinous processes. The support member defines a lumen between a proximal end and a distal end of the support member. An expandable member is inserted through the lumen of the support member such that a distal end portion of the expandable member is disposed outside a distal end of the lumen and a proximal end portion of the expandable member is disposed outside a proximal end of the lumen. The distal end portion and the proximal end portion of the expandable member are then expanded such that each of the distal end portion and the proximal end portion of the expandable member has an outer diameter greater than an outer diameter of the support member.