Study design: Prospective consecutive series.
Objective: To evaluate the efficacy of minimal invasive surgery for acute lumbar fractures by means of balloon kyphoplasty with calcium phosphate plus segmental short posterior instrumented fusion.
Summary of background data: In the surgical treatment of lumbar fractures with short pedicle screw instrumentation, the failure to support the anterior spinal column often results in loss of correction. Transpedicular augmentation techniques with bone and bone substitutes have been attempted whereas kyphoplasty has been increasingly used to augment fractured vertebral body.
Methods: Eighteen consecutive patients with an average age of 64 +/- 15 years, who sustained lumbar (L1-L4) burst and severe compression fracture were included in this prospective study. On admission, 2 (11%) of 18 patients had incomplete neurologic impairment. All patients underwent bilateral balloon kyphoplasty with calcium phosphate bone cement to reduce segmental kyphosis and restore vertebral body height and segmental pedicle screw instrumentation and fusion. Gardner kyphosis angle, anterior (AVBHr) and posterior vertebral body height ratio (PVBHr), and spinal canal encroachment (SCE) were calculated before to after surgery. VAS and SF-36 were used to evaluate functional outcome.
Results: All patients were operated within 24 hours after admission and were followed for an average 22 months (17-28 months) after index surgery. Operating time and blood loss averaged 45 minutes and 70 mL, respectively. VAS and SF-36 (role physical and bodily pain domains) were significantly improved after surgery. Both patients with incomplete neurologic lesions recovered, whereas no neurologic deterioration was observed in any case. Segmental kyphosis improved from an average preoperative kyphosis of 16 to 2 degrees after surgery (P < 0.000). AVBHr improved from an average before surgery 0.57 to 0.87 (P < 0.000) after surgery, whereas PVBHr improved from 0.93 before surgery to 0.98 (P < 0.05) after surgery. SCE was reduced from an average 25% before surgery to 19% (P < 0.07) after surgery. Bone cement leakage was observed anteriorly to the fractured vertebral body or to the adjacent superior disc in 4 patients without clinical sequelae, whereas 3 pedicle screws were malpositioned medially to the pedicle in 3 patients without neurologic impairment or associated complaints. Posterolateral radiologic fusion was achieved within 6 to 8 months after index operation. There was no instrumentation failure or loss of sagittal curve and vertebral height correction.
Conclusion: Balloon kyphoplasty with calcium phosphate cement combined with posterior segmental short minimal invasive fixation for fresh burst and severe compression lumbar fractures provided excellent immediate reduction of post-traumatic segmental kyphosis with simultaneous reduction of spinal canal encroachment and restoration of vertebral body height in the fracture level.