Radiological studies and clinical significance on the middle height of fractured vertebral body for thoracolumbar fractures after posterior short-segment instrumentation

English Keywords:Thoracolumbar fracture  Short-segment instrumentation  Middle height of vertebral body  Endplate injury

English Abstract:

  【Abstract】 Objectives: To analyze the clinical outcome of short-segment pedicle screw fixation on the recovery of the middle height of fractured vertebral body in thoracolumbar fracture. Methods: From January 2011 to December 2012, 67 patients with thoracolumbar type A　spinal injuries were treated with short-segment fixation. There were 36 males and 31 females with a mean age of 37.8±7.5 years(range, 17-52 years). The types were T11-L2 single-segment vertebral fractures(AO type A) without serious neurologic deficits(ASIA type D, E). All patients were divided into two groups based on different instrumentations, group A(n=37) was treated with fixation via injured vertebra, whereas group B(n=30) skipping injured vertebra. By using the PACS imaging system to measure the anterior(Ha), middle(Hm) and posterior(Hp) height of fractured vertebral body, and the kyphotic Cobb angle on lateral　X-ray films at preoperation, 1 week of postoperation and final follow-up, then the compression ratios of Ha and Hm were calculated to observe the recovery of the middle height of fractured vertebral body. Results: The mean follow-up time was 26.5±8.9 months(range, 18-40 months). Regardless of fixation type, postoperative compression ratios of Ha or Hm and Cobb angle significantly decreased compared with preoperation(P<0.05). At preoperation, 1 week after operation and final follow-up, the compression ratio of Hm was (44.8±10.3)%, (31.6±7.1)% and (31.3±6.8)% respectively in group A, likewise (38.6±8.3)%, (32.0±8.4)% and (31.7±8.6)% respectively in group B. In terms of Hm, there was still 30% loss of height in two groups. Conclusions: Both two fixations can recover the height of fractured vertebral body and kyphosis Cobb angle, but there is obvious loss of height for Hm at postoperation.