32. The effect of transpedicular injection of rhBMP-2 injection on prevention of proximal junctional kyphosis

BACKGROUND CONTEXT

Several studies have explored strategies to prevent proximal junctional kyphosis (PJK). Our study introduces a novel strategy to address the unresolved issue of PJK in ASD, utilizing recombinant human bone morphogenetic protein-2 (rhBMP-2).

PURPOSE

This study aimed to investigate the preventive effects of upper instrumented vertebrae (UIV) rhBMP-2 injection on PJK and proximal junctional failure (PJF) and to determine whether UIV bone density significantly increases locally.

STUDY DESIGN/SETTING

A retrospective and prospective case-control study.

PATIENT SAMPLE

The sample consists of 154 patients with ASD (adult spine deformity)

OUTCOME MEASURES

Incidence of PJK and PJF and change in the Hounsfield unit of UIV after 1 year of follow-up

METHODS

All surgeries were performed with instrumentation and fusion from iliac to T10. In the experimental group, consisting of 25 patients with ASD, rhBMP-2 injection was administered to the vertebral body of UIV. To minimize performance bias, the control-1 group included 66 patients who had undergone ASD surgery by the same surgeon in the year preceding the commencement of the study. Control-2 consisted of 63 patients who had undergone ASD surgery by the same surgeon during the year following the end of the study for experimental group. Postoperatively, we evaluated the presence of PJK and PJF, change in the Hounsfield unit (HU) of UIV after 1 year of follow-up. The control-1 group was respectively collected data and the experimental group and control-2 group were prospectively collected data.

RESULTS

When comparing baseline characteristics with control groups, a significant difference was observed only in BMI with control-1 (p=0.006), control-total (control-1 + control-2, p=0.026) having a higher BMI than the study group. In the group that received rhBMP-2 at UIV, there were 3 cases (12.0%) of PJK, whereas the control-1 and control-2 had 26 cases (39.4%, BMI-adjusted p=0.010) and 20 cases (31.7%, BMI-adjusted p=0.078), respectively. In the control-total group (combining control-1 and control-2 groups), there were 46 cases (35.7%, BMI-adjusted p=0.025) of PJK. Regarding HU measurements, the UIV that received rhBMP-2 showed a statistically significant increase compared with the preoperative values one year after surgery (p=0.001).

CONCLUSIONS

Injection of rhBMP-2 at the UIV effectively increased trabecular bone density at the UIV, thereby significantly contributing to the prevention of PJK.

FDA Device/Drug Status

This abstract does not discuss or include any applicable devices or drugs.