Spinous process morphometry for interspinous device implantation in korean patients

Objective: To analyze the interspinous distance and the height, length, and thickness of the lumbar spinous process for interspinous device implantation in Korean patients. Methods: Morphometric data obtained from plain radiographs of the lumbar and sacral spine were analyzed. The study included 60 matched subjects who visited an outpatient clinic for back pain. Exclusion criteria included collapsed intervertebral disc, lumbarization, and sacralization. There were 34 men and 26 women; age range was the 20s to 70s, with 10 subjects in each decade. The interspinous distance and height, length, and thickness of the lumbar spinous process were obtained on lateral radiographs using an image analysis program (M-view 5.4; Marotech). Results: The largest interspinous distance was at L2-3, with a mean of 12 mm (range 6-22 mm), and the smallest distance was at L5-S1, with a mean of 8 mm (range 3-16 mm). The interspinous distance became shorter from L1-2 to L5-S1. A negative correlation was noted between age and interspinous distance in the L1-5 levels (L1-2, y = -0.11x + 17.27, r² = 0.34, P < 0.0001; L2-3, y = -0.07x + 15.68, r ² = 0.12, P = 0.0058; L3-4, y = -0.08x + 14.39, r² = 0.27, P < 0.0001; L4-5, y = -0.05x + 11.65,r² = 0.096, P = 0.0158; L5-S1, y = -0.02x + 9.25, r² = 0.028, P = 0.1982). Conclusions: There is a decreasing trend in the interspinous distance in the L1-5 levels with advancing years. Taking progressive collapse of the interspinous distance with the aging process into consideration, interspinous implants should be carefully selected in younger patients.