Fluoroscopically-guided injections to treat "kissing spine" disease.

BACKGROUND Any spine structure that is innervated by afferent nociceptive nerve fibers is a potential pain generator. In the lumbar spine, the most studied pain generators include: sacroiliac joints, the zygapophysial joints, the intervertebral discs, myofascial structures. Anomalous lumbosacral articulations, the spinous processes, and lumbar spine osteophytes are less commonly reported. OBJECTIVE To describe the diagnostic and therapeutic features of "kissing spine" disease or Baastrup's Sign with particular attention to MRI findings and fluoroscopically-guided injection therapy. DESIGN A series of 3 patients with axial low back pain presented with exam findings and MRI changes suggestive of pain emanating from adjacent spinous processes that appeared to be in direct contact or very closely opposed. This has been described in the literature as "kissing spine" disease or Baastrup's sign. Fluoroscopically-guided injections were performed and the responses were studied. RESULTS The 3 patients had MRI findings consisting of inflammation and/or edema in the spinous processes and surrounding soft tissues. Fluoroscopically-guided injections provided pain relief in all 3 patients. One patient with recurrent pain eventually underwent successful surgical resection of the involved spinous processes. CONCLUSION Painful adjacent and closely opposed spinous processes can be a source of axial low back pain. We have described MRI features and the responses to fluoroscopically-guided injections in 3 patients with this condition.