Lumbar spondylolysis is a fatigue fracture of the pars interarticularis that is common during adolescent athletes. It is known that bilateral spondylolysis with combination of acute phase on one side and pseudarthrosis phase on another side at the first visit is common. And the union rate of the combination with conservative treatment is significantly lower than that with conventional treatment. The purpose of this study was to determine the factors that inhibit union of the acute phase side with conservative treatment in spondylolysis with combination of acute phase on one side and pseudarthrosis phase on another side
Methods: Among lumbar spondylolysis patients of high school age or younger who presented with low back pain after April 2014, 37 cases of bilateral spondylolysis in which one side was acute and the contralateral side was pseudarthrosis at the initial visit were included. The subjects were divided into two groups: 10 cases in which union was achieved with conservative treatment (U group) and 27 cases in which was resulted in non-union(P group). The analysis items were L5 or non-L5, presence or absence of spina bifida occulta (SBO), and progressive stage or not about pathological stage. The Fisher exact test was used as the statistical method for comparison.
Results: In the U group, 7 patients was on L5 and 3 patients was on non-L5, and in the P group, 23 patients was on L5 and 4 patients was on non-L5 (P=0.36, significance level P<0.05). Regarding SBO, 5 patients had SBO and 5 patients did not in the U group, while 17 patients had SBO and 10 patients did not in the P group (P=0.71). Regarding pathological stave, in the U group, 2 patients was progressive stage disease and 8 patients was not, while 19 patients had progressive stage disease and 8 patients was not in the P group (P=0.01).
Discussion: The results of the present study showed that in bilateral spondylolysis with contralateral pseudarthrosis, there were significantly more progressive stages of acute lesions in the group in which union was not finally achieved. The treatment plan should be based on the information that union is difficult to obtain in progressive stage lumbar spondylolysis in which the contralateral side is pseudarthrosis.