invention can be facilitated by imaging in this context the spine can be imaged using any suitable technology including but not limited to 2d 3d fluoroscopy ct mri ultrasound or with direct visualization with fiber optic or microsurgical techniques stereotactic or computerized image fusion techniques are also suitable fluoroscopy is currently particularly well suited to the techniques disclosed herein fluoroscopic equipment is safe and easy to use readily available in most medical facilities relatively inexpensive in a typical procedure using direct biplane fluoroscopic guidance and local anesthesia the epidural space is accessed adjacent to the surgical site as described above if the injected medium is radio opaque as are for example myelographic contrast media the margins of the expanded epidural space will be readily visible using fluoroscopy or ct imaging thus the safety zone created by the present contrast guided dural compression techniques can reduce the risk of damage to the spinal cord during procedures to remove or displace portions of the ligamentum flavum and or laminae in order to treat spinal stenosis if desired the injected medium can be provided as a re absorbable water soluble gel so as to better localize the safety zone at the site of surgery and reduce leakage of this protective layer from the spinal canal an injectable gel is a significant improvement on prior epidural injection techniques the gel is preferably substantially more viscid than conventional contrast media and.