Devices and methods for the treatment of abnormal spinal stability and stenosis of the spinal canal by the implantation of orthopedic devices between skeletal segments. In one embodiment, a device is disclosed to rigidly fixate the spinous processes of two vertebral bones relative one another. A first member of the device is advanced across an interspinous space, rotated, and/or advanced onto the contralateral side of the spinous processes. A second member of the device is also advanced onto the ipsilateral side of the spinous processes and forcibly captures the spinous processes between the first and second members. A protrusion extends from the first and/or second devices configured to embed into the bone of the spinous processes thereby increasing the immobilization strength of the device. The implant may be further configured to contain a bone forming material to form a fusion between the first and the second vertebral bones.