[Case-control study on endplate injury of lumbar spine with two different intervertebral fusion methods]

To summarize and compare the endplate injury occurrence characteristics and clinical results of transforaminal intervertebral fusion combined with pedicle screw fixation through intermuscular approach and oblique lateral intervertebral fusion combined with pedicle screw fixation in the treatment of lumbar disease.

A retrospective analysis of 213 cases of lumbar disease admitted from January 2016 to June 2019, including 73 males and 140 females. The age ranged from 24 to 81 years old, with an average of(54.9±10.5) years old. The courses of disease ranged from 6 to 180 months, with an average of (40.30±28.71) months. There were 35 cases of degenerative lumbar intervertebral disc disease, 22 cases of giant lumbar disc herniation, 15 cases of discogenic low back pain, 9 cases of primary lumbar intervertebral inflammation at the turn of inflammation, 52 cases of lumbar spinal stenosis, 47 cases of lumbar degenerative spondylolisthesis, 33 cases of lumbar spondylolysis with or without spondylolisthesis. There were 191 cases of single-segment lesions, including 5 cases on L2, 3, 24 cases on L3, 4, 162 cases on L4, 5. And there were 22 cases of two-segment lesions, including 3 cases on L2, 3 and L3, 4, and 19 cases on L3, 4 and L4, 5. One hundred and ten cases were taken by bilateral pedicle screw fixation and interbody fusion under the posterior muscle space approach (abbreviated as posterior fusion group), and 103 cases were taken by oblique lateral interbody fusion combined with bilateral pedicle screw fixation under the posterior muscle space approach (oblique lateral fusion group). Observed the characteristics of endplate injury in the two groups, and compared the clinical and imaging results and complications of the two groups.

There were 8 cases of endplate injury occurred in 9 segments in the posterior fusion group. According to the number of cases, the incidence rate was 7.27%(8/110), 1 case was male, 7 cases were female, with an average age of (63.22±3.51) years old. Among the 8 cases, there were 7 cases of bone loss or osteoporosis before the operation, 5 cases using banana fusion cages, 3 cases using anatomical fusion cages. Three cases occurred in the upper endplate of the vertebral body and 6 cases in the inferior endplate of the vertebral body. In the oblique lateral fusion group, there were 21 cases of endplate injury in 24 segments, and the incidence rate was 20.39%(21/103). There were 4 males and 17 females, with an average age of (62.50±5.02) years old. Among the 21 cases, 16 cases were bone loss or osteoporosis before operation. There were 5 cases used large fusion cages, 4 cases had abnormal endplate anatomy, and 3 cases had iliac crest hypertrophy. It occurred in 20 segments of the upper endplate of the vertebral body, and 4 segments of the lower endplate of the vertebral body. Two of the 21 cases of endplate injury combined with vertebral body fractures. The incidence of endplate injury of the posterior fusion group was significantly lower than that of the oblique lateral fusion group. No incision infection occurred in the two groups, the follow-up time was ranged from 12 to 48 months, and the median follow-up period was 12 months. In the follow-up, 22 cases occurred fusion cage subsidence in the posterior fusion group, 43 cases in the oblique lateral fusion group, and 1 case in each group occurred fusion cage displacement. There was no loosening, displacement or breakage of the internal fixation. The incidence of complications in the oblique lateral fusion group 33.98%(35/103) was significantly higher than that in the posterior fusion group 23.64%(26/110), P=0.039. The height of the intervertebral space in both groups recovered well after the operation, but it was lost to varying degrees during follow-up. The fusion rate of the posterior fusion group was 94.5%(104/110), and 96.1%(99/103) in the oblique lateral fusion group(P=0.083). At the latest follow-up, the clinical symptoms of the two groups of patients were significantly improved.

Two methods in treating single or two-segment lumbar spine lesions obtained good clinical effects. The characteristics of endplate injury in the two fusion methods are not completely the same. Although the endplate injury did not affect the final clinical results of the two fixed fusion methods, it still needs to be paid attention to and emphasize the prevention and effective treatment of endplate injury, especially for oblique lateral intervertebral fusion.