Early Sternal Bone Healing after Thermoreactive Nitinol Flexigrip Sternal Closure

Abstract

Purpose: Thermoreactive nitinol Flexigrip has been developed to ensure better fixation than conventional wire closure. To verify the advantage of Flexigrip over the conventional wiring, we compared early sternal bone healing on computed tomography (CT).

Methods: A prospective cohort study enrolled the first consecutive 80 patients with wiring and the second consecutive 44 patients undergoing Flexigrip sternal closure. The primary endpoint was sternal healing evaluated quantitatively using a 6-point scale and measured gaps/offsets of the sternal halves at 6 levels on CT scans on the 14th postoperative day. Secondary endpoints included pain scores and sternal complications 1 month after surgery.

Results: Compared with the patients of wiring, those who received Flexigrips showed higher 6-point scores at most sternum levels, less frequent gaps (52% vs 70%, p = 0.04), lower offsets (3.3 ± 0.9 mm vs 4.3 ± 0.7 mm, p <0.001) at the manubrium, and less frequent gaps (25% vs 43%, p = 0.04) and offsets (2.3% vs 24%, p = 0.002) at the middle of sternum. The pain scores and sternal complication rates were similar between both groups.

Conclusion: CT evaluation 2 weeks after surgery revealed that Flexigrip sternal closure showed less gaps and offsets of the sternal halves, suggesting faster sternal bone union when compared to the wiring.

Keywords: Flexigrip; gap; offset; sternal closure; wiring.

Fig. 1. The left figure shows six levels for evaluating sternal bone healing on CT. The right figure shows the quantitative parameters of the axial sections on CT for evaluating sternal bone healing at each level. CT: computed tomography

Fig. 2. The sternal closure methods using Flexigrip and the sizes of the used Flexigrips. Blue indicates stainless wires and red indicates Flexigrips. ICS: intercostal space