An Imaging Anatomical Study on Percutaneous Kyphoplasty for Lumbar Via a Unilateral Transverse Process-Pedicle Approach

In Brief Study Design. An imaging anatomical measurement. Objective. To investigate the anatomical feasibility of percutaneous kyphoplasty for lumbar osteoporotic vertebral compression fractures via a unilateral transverse process-pedicle approach (TPA). Summary of Background Data. Kyphoplasty via a unilateral approach has been reported and good clinical results have been achieved. However, because of the lack of an anatomical study, these approaches have yet to be popularized. Methods. A total of 150 lumbar vertebral bodies of 30 patients were simulated kyphoplasty on the computed tomographic scans through conventional transpedicle approach (CTA) and the TPA, respectively. Anatomical parameters including the distance between the entry point and the midline of the vertebral body, the puncture inclination angle, and the success rate of puncture were measured and compared. Results. The distance between the entry point and the midline from L1 to L5 lumbar levels varied from 20.6 ± 2.2 mm to 28.6 ± 2.9 mm in the CTA group and from 23.6 ± 2.2 mm to 33.6 ± 2.9 mm in the TPA group. The entry point from L1 to L5 in the TPA group was 3.0 ± 2.1 mm to 5.1 ± 2.7 mm more lateral than that in the CTA group. The medial inclination angles from L1 to L5 were 30.2° ± 6.4° to 47.7° ± 5.4° in the TPA and 15.3° ± 6.0° to 22.8° ± 8.7° in the CTA group. The inclination angles in the TPA group were greater than that in the CTA group and the safe range of the puncture angles was also wider. The success rate was 51.7% in the CTA group and 87.7% in the TPA group. Conclusion. The entry point through a TPA was localized at the midline of the transverse process, 3.0 to 5.1 mm outside the lateral margin of the pedicle projection. Compared with CTA, the puncture inclination angle in the TPA approach was much larger with a wider safe puncture range. The TPA approach allowed an easy puncture to meet or surpass the midline of the lumbar vertebral body. Level of Evidence: N/A We report an imaging anatomy study of the characteristics of percutaneous kyphoplasty through a transverse process-pedicle approach (TPA) approach, compared with a conventional transpedicle approach. We found that puncture via a TPA approach was easier and safer to reach to or surpass the midline of the lumbar vertebral body.