Surgical Intervention for Osteoporotic Vertebral Burst Fractures in Middle-low Lumbar Spine with Special Reference to Postoperative Complications Affecting Surgical Outcomes

Abstract

The purpose of this study was to investigate the clinical and radiological features of osteoporotic burst fractures affecting levels below the second lumbar (middle-low lumbar) vertebrae, and to clarify the appropriate surgical procedure to avoid postoperative complications. Thirty-eight consecutive patients (nine male, 29 female; mean age: 74.8 years; range: 60-86 years) with burst fractures affecting the middle-low lumbar vertebrae who underwent posterior-instrumented fusion were included. Using the Magerl classification system, these fractures were classified into three types: 16 patients with superior incomplete burst fracture (superior-type), 11 patients with inferior incomplete burst fracture (inferior-type) and 11 patients with complete burst fracture (complete-type). The clinical features were investigated for each type, and postoperative complications such as postoperative vertebral collapse (PVC) and instrumentation failure were assessed after a mean follow-up period of 3.1 years (range: 1-8.1 years). All patients suffered from severe leg pain by radiculopathy, except one with superior-type fracture who exhibited cauda equina syndrome. Nineteen of 27 patients with superior- or inferior-type fracture were found to have spondylolisthesis due to segmental instability. Although postoperative neurological status improved significantly, lumbar lordosis and segmental lordosis at the fused level deteriorated from the postoperative period to the final follow-up due to postoperative complications caused mainly by PVC (29%) and instrument failure (37%). Posterior-instrumented fusion led to a good clinical outcome; however, a higher incidence of postoperative complications due to bone fragility was inevitable. Therefore, short-segment instrument and fusion with some augumentation techniqus, together with strong osteoporotic medications may be required to avoid such complications.

Keywords: middle-low lumbar spine; osteoporotic vertebral burst fracture; posterior decompression and fusion.

Fig. 1.

Preoperative MRI images showing the three types of burst fracture according to the Magerl classification system. (A) Superior-type patient with superior incomplete burst fracture (arrow). (B) Inferior-type patient with inferior incomplete burst fracture (arrow). (C) Complete-type patient with complete burst fracture (arrow). Arrowheads indicate regions of collapse. MRI: magnetic resonance imaging.

Fig. 2.

Case of an 85-year-old woman with L3 complete burst fracture (complete-type) and old compression fractures at L4 with degenerative spondylolisthesis, who was presented with severe low back pain and bilateral radicular thigh pain. (A) Preoperative lateral plain radiograph, showing L3 vertebral collapse with spondylolisthesis at L4–5. (B) Preoperative sagittal T₂-weighted MR image showing multiple canal stenosis at L2–3, L3–4 and L4–5 levels with vertebral cleft sign (arrows) at L3. (C) Preoperative myelogram showing L3 collapse and complete block at L2–3. (D) Preoperative axial CT scan showing L3 collapse with bilateral pedicle fracture (arrowhead) and canal stenosis due to bony fragments (arrows). (E and F) Coronal (E) and sagittal (F) radiographs at final follow-up, showing successful fusion after PLIF at L2–3, L3–4 and L4–5 levels despite pedicle screw loosening with a change of placement status (arrowhead). PLIF: posterior lumbar interbody fusion.

Fig. 3.

Surgical intervention algorithm for osteoporotic vertebral burst fractures in middle-low lumbar spine. PLF: posterolateral fusion, PLIF, posterior lumbar interbody fusion; VP: vertebroplasty.