A method for inserting an interspinous spinal implant into an opened gap between first and second spinous processes of adjacent superior and inferior vertebras, respectively includes the following. First forming an opened gap between a first spinous processes of a superior vertebra and a second spinous processes of an adjacent inferior vertebra by first inserting a decompression knife into diseased areas of the adjacent superior and inferior vertebras, then cutting fascia tissue, then separating soft tissue from bone by rocking the decompression knife back and forth, and then inserting a broach cutter into the diseased areas of the adjacent superior and inferior vertebras and cutting interspinous ligament between the adjacent superior and inferior vertebras. Next, determining and selecting an appropriate sized and shaped interspinous spinal implant for the opened gap by inserting a sizing tool into the opened gap, and sizing the opened gap with the sizing tool. Next, inserting the selected interspinous spinal implant into the opened gap with an insertion tool, and then compressing first and second elongated components of the interspinous spinal implant onto first and second opposite sides of the first and second spinous processes with a compressor tool, respectively. Finally, locking the interspinous spinal implant onto the first and second spinous processes of the adjacent superior and inferior vertebras with a locking driver.