Clinical assessment of efficacy of poly-L-lactide sternal pin on sternal stability and post-operative pain: a prospective randomized trial in cardiovascular surgery

BACKGROUND: Although the incident rate is low, sternal dislocation and dehiscence due to unstable sternal fixation after cardiovascular surgery could cause potentially lethal complications. Thus, to enforce the stability of closed sternum, the sternal pins have been utilized at surgeon’s discretion. However, there is no randomized clinical trial to test whether these pins are effective to stabilize a sternum. Hence, this study aimed to examine the clinical efficacy of bioabsorbable poly-L-lactide (PLLA) sternal pins in reinforcing sternal stability and preventing instability of the sternum after full sternotomy. METHODS: We conducted a single institutional, prospective, randomized, single-blinded clinical study involving 100 patients who underwent an initial cardiovascular surgery via sternotomy. Patients were randomly allocated into two groups: with (group P) and without (group N) PLLA sternal pins, at 1:1 ratio from November 2013 to April 2016. Sternal deviation and stability were assessed with postoperative computed tomography (CT) at two postures to put shear stress on the sternum. Additionally, information on patient demographic indices was obtained prospectively, and patient’s pain intensity was assessed with numerical rating scoring system during rehabilitation. Furthermore, propensity score matching was performed for further comparative sub-analysis. RESULTS: Ninety-one patients (43 in group P and 48 in group N) were analyzed using the intention-to-treat method. Group N had a significantly higher proportion of males (P=0.015) and ischemic disease as a primary diagnosis (P=0.040) than group P. Postoperative CT showed that the degree of sternal deviation and stability were comparable between the groups. Similarly, the numerical rating score of pain during rehabilitation showed no difference between the groups. Even after adjusting for patient characteristics using propensity score matching method, no significant differences in sternal gaps, stability, and numerical rating score of pain were observed. Of note, no material-related adverse event such as wound infection was found. CONCLUSIONS: We could not identify the efficacy of the sternal pin in enforcing sternal stability based on CT measurements with mild shear stress on sternum after cardiovascular surgery. Nevertheless, our results with no adverse events might encourage further investigations with a more specific cohort who is susceptible to infection but requires an additional sternal fixation. TRIAL REGISTRATION: This study was registered in University Hospital Medical Information Network Clinical Trial Registry (UMIN000017357).