An injectable, flexible interspinous process device and a delivery system. The interspinous process device is flexible and can be fillable in situ with a desired amount of biocompatible material. The interspinous process device has a container portion. A support element, such as a self-expanding mesh, is used in conjunction with the container to provide added structural support. The mesh also facilitates deployment of the device when it is properly positioned. A conduit may be coupled to the interspinous process to fill the device. A delivery system is also provided for delivering the flexible interspinous process device to the desired location. The delivery system includes an outer catheter that is disposed over the interspinous process device to maintain it in the undeployed state and thus facilitate delivery of the device to the desired location. An inner removable sleeve and a guidewire may also be used with the delivery system.