An implant assembly for implantation between upper and lower spinous processes includes an interspinous implant and a removable clip. The implant may have an interspinous portion having upper and lower surfaces for engagement with the respective upper and lower spinous process, and a thickness therebetween sufficient to restore anatomical tension to the supra-spinous posterior ligament. Upper and lower pairs of lugs extend from the interspinous portion for interfacing with the respective spinous processes. One or more of the lugs of each pair is movable between an insertion configuration and a retention configuration substantially perpendicular to the retention configuration. The removable clip engages the relevant lugs to selectively retain the same in the insertion configuration.