Percutaneous vertebroplasty for osteoporotic vertebral compression fracture with intravertebral cleft associated with delayed neurologic deficit

Abstract

Introduction: The number of cases of osteoporotic vertebral compression fracture (OVCF) with intravertebral cleft (IVC) with delayed neurologic deficit (DND) is increasing as the population ages. However, the cause of DND is poorly understood, and no definitive treatment of the disease has been established. The purpose of this study was to clarify the radiographic parameters contributing to the occurrence of DND, and to evaluate the efficacy and safety of percutaneous vertebroplasty for this pathology.

Methods: Percutaneous vertebroplasty was prospectively performed for 244 patients with OVCF with IVC; 30 had DND and 214 did not. Radiographic parameters of local kyphotic angle, percent spinal canal compromise and intravertebral instability were investigated for correlations to DND. Procedural outcomes were evaluated using visual analog scale (VAS), Oswestry Disability Index (ODI), and modified Frankel grades.

Results: Before vertebroplasty, no substantial difference in local kyphotic angle was seen between OVCF with IVC with and without DND, but percent spinal canal compromise and intravertebral instability were greater in OVCF with IVC with DND (P < 0.001). After vertebroplasty, 25 of 30 cases (84%) of OVCF with IVC with DND achieved clinically meaningful improvement (CMI), but 5 (17%) did not. Patients with CMI showed substantial improvements in intravertebral instability (P < 0.001), and no change in local kyphotic angle or percent spinal canal compromise. In five patients without CMI, four showed an initial improvement, but subsequent vertebral fracture adjacent to the treated vertebra caused neurologic re-deterioration. One patient with percent spinal canal compromise 54.9% and intravertebral instability 4° achieved no neurologic improvement following vertebroplasty. No serious complications or adverse events related to the procedure were encountered.

Conclusions: Intravertebral instability is the dominant cause of DND. Percutaneous vertebroplasty appears effective and safe in the treatment of OVCF with IVC with DND. Patients with less intravertebral instability and severe spinal canal compromise could be candidates for conventional surgical treatment.

Fig. 1

The following sequence of images illustrates a patient with osteoporotic vertebral compression fracture with intravertebral cleft. a The fracture compresses through the intravertebral cleft beneath the superior endplate, demonstrating the maximal degree of height loss on lateral radiography with the patient in a sitting position. b The fracture plane gaps open because the patient is undergoing reformatted CT in a supine position (arrow). c Sagittal T2-weighed MR image demonstrating an area of hyperintensity within a region of hypointensity (arrow). d Sagittal fat-suppressed contrast-enhanced MR image revealing an intravertebral cleft as a non-contrast area (arrow)

Fig. 2

Three radiographic parameters demonstrating a “local kyphotic angle” (α°) measured using Cobb’s method with the patient in a sitting position and b “percent spinal canal compromise” calculated by dividing the area of intrusion by the total spinal canal area multiplied by 100. The total canal area is outlined by the solid line; the area of the retropulsed vertebral wall is demarcated by the dotted line. Areas of the spinal canal and retropulsed posterior wall are calculated from the total number of pixels per cross-sectional area (pixel/mm²). a, c “Intravertebral instability”, defined as the difference between local kyphotic angle on lateral radiography with the patient in a sitting position (α°) and that on a sagittal reformatted CT scan in a supine position (β°); α°–β°

Fig. 3

Post-procedural scores of VAS, ODI, and numeric neurologic functional grade in patients with CMI. VAS score for low back pain (a) and ODI (b) were improved immediately after vertebroplasty (P < 0.001). Numeric neurologic functional grade (c) gradually improved after the intervention (1 month: P = 0.005; 6–24 months: P < 0.001) for comparison with baseline scores. Results are expressed as mean ± standard deviation (SD). VAS visual analog scale, DND delayed neurologic deficit, CMI clinically meaningful improvement, ODI Oswestry disability index