Effect of Inter-spinous Processes Separation on Morphologic Change of LFJ and Intervertebral Foramen

Objective To observe the effect of inter-spinous process separation on morphologic change of lumbar facet joints(LFJ) and intervertebral foramen.Methods A total of 6 human fresh cadaveric spines with all the ligaments kept were used in this research.LFJ relative displacement and intervertebral foramen height and width change were measured when L3/4,L4/5 spinous process were separated.Result L3/4,L4/5 intervertebral foramen height increase and LFJ displacement obviously improved,when the spinous processes were distracted 2 mm and 4 mm.There was no obvious difference in the intervertebral foramen width when the spinous processes were distracted 2 mm,but the intervertebral foramen width increase significantly when Inter-spinous processes were separated 4 mm.Conclusion Inter-spinous process separation can effectively improve LFJ displacement,increase the intervertebral foramen height,but the inter-spinous process separation should be wide enough to the increase of the intervertebral foramen width.