A Randomized Trial to Assess the Contribution of a Novel Thorax Support Vest (Corset) in Preventing Mechanical Complications of Median Sternotomy

Mechanical complications of median sternotomy are less frequent than infective complications, but are a significant cause of morbidity and, occasionally, of mortality in patients undergoing cardiac surgery [1, 2]. These complications can lead to a prolonged hospitalization and sometimes require surgical sternum revision [1, 2]. The increased utilization of resources in terms of the duration of hospitalization, staff work-hours, use of materials and of infrastructure, result in higher health care costs [1, 3]. The limitations imposed on the reimbursement of health care expenditures, especially in recent years, have heightened the importance of preventing post-sternotomy induced complications and the need to reduce re-admissions and mean hospitalization times whilst, at the same time, be able to provide the best patient recovery and subsequent quality of life [4]. Furthermore, anatomically imperfect sternal healing may cause chronic pain and affect the chest mobility for many subsequent years [5‐7].

The present research has a particular focus on mechanical sternal dehiscence [8], a topic only marginally treated by other papers [9‐11].

We have adopted the Posthorax support vest (Epple, Inc., Vienna, Austria) as its design stabilizes the sternum following sternotomy, relieves pressure on the suture wires and reduces pain when breathing, coughing, and during rehabilitation.

The aim of this study was to assess the prevention of mechanical complications of median sternotomy and the improvement of the anatomical sternum healing by means of the utilization of the Posthorax support vest and to evaluate its impact on in-hospital recovery in a group of patients at high risk for sternal dehiscence.

Patient clinical and operative characteristics are shown in Table 1. The average number of requests for supplemental analgesia was lower in group A compared to group B but the difference did not reach statistical significance (1.6 ± 0.4 vs. 2.0 ± 0.5, p = NS) (Table 2). However, a subgroup analysis demonstrated a significant decrease in requests for supplemental analgesia in favor of group A in the following subgroups: those of age <70 years (1.4 ± 0.1 vs. 2.3 ± 0.2, p = 0.002), males (1.3 ± 0.2 vs. 2.1 ± 0.1, p = 0.005), patients with weight ≥80 kg (1.7 ± 0.1 vs. 3.6 ± 0.2, p = 0.001) or with a BMI ≥25 (1.6 ± 0.2 vs. 3.3 ± 0.3, p = 0.005), those with COPD (1.9 ± 0.1 vs. 4.2 ± 0.2, p = 0.001), and those which underwent BIMA harvesting (1.4 ± 0.1 vs. 3.2 ± 0.2, p = 0.001) (Table 2). The mean VAS pain score was significantly lower in group A than in group B (2.4 ± 0.3 vs. 3.4 ± 0.6, p = 0.02), a difference which in the subgroup analysis was more pronounced in the following subgroups: those of age <70 years (2.4 ± 0.2 vs. 4.3 ± 0.4, p = 0.001), males (2.2 ± 0.1 vs. 3.6 ± 0.3, p = 0.005), patients with weight ≥80 kg (2.1 ± 0.3 vs. 4.2 ± 0.1, p = 0.001) or with BMI ≥25 (2.3 ± 0.2 vs. 4.3 ± 0.2, p = 0.001), those with COPD (3.1 ± 0.5 vs. 4.7 ± 0.6, p = 0.002), and those which underwent BIMA harvesting (1.8 ± 0.1 vs. 4.6 ± 0.7, p < 0.001) (Table 3). Given the overall significant difference demonstrated that there was a significant reduction in pain scores between group A and group B across all types of surgery including coronary artery bypass grafting (CABG), (1.8 ± 0.4 vs. 3.1 ± 0.6, p = 0.01), aortic valve replacement (AVR), (2.8 ± 0.4 vs. 3.7 ± 0.2, p = 0.05), mitral valve replacement or repair (MVR), (2.4 ± 0.2 vs. 3.4 ± 0.4, p = 0.02), ascending aorta/arch replacement (AAR), (2.8 ± 0.3 vs. 3.6 ± 1.1, p = 0.05), and in combined surgery (2.3 ± 0.3 vs. 3.4 ± 0.3, p = 0.02) (Table 3). The EQ-5D analysis of post-operative quality of life demonstrated significantly better results in terms of freedom of limitations in mobility (70 vs. 30%, p = 0.001) and self care (73.5 vs. 46.4%, p = 0.002), in totally limited activity (10.3 vs. 24.5%, p = 0.005), in freedom from pain (43.2 vs. 10.3%, p = 0.001), and in absence of anxiety (49.7 vs. 29.6%, p = 0.05) in group A compared to group B (Table 4). At discharge there were no cases of re-operation for mechanically induced sternum complication in group A vs. seven cases in group B (Table 5). At discharge, a sternotomy stripe of lucency >2 mm was observed in seven patients in group A and in 31 patients in group B (4.5 vs. 20%, p = 0.005), and a clear interruption/dislocation of the sternotomy line was observed in eight patients in group B and none in group A (5.2 vs. 0%) (Table 5). The average days of in-hospital stay were significantly lower in group A compared to group B (7 ± 2.7 vs. 12 ± 3.4, p = 0.02) (Table 5). None of the patients in group A vs. three patients of group B developed post-operative pneumonia. In group B, 16 patients were re-admitted during the follow-up period for post-sternotomy mechanically induced complications vs. six patients in group A (3.9 vs. 10.3%, p = 0.05) (Table 5). The mean post re-admission hospital stay was significantly lower in group A (8 ± 3.2 days) vs. group B (24 ± 7 days, p = 0.05) (Table 5). There were no other complications of any kind reported with the usage of the Posthorax sternum support vest in group A patients. The mean follow-up was 2.4 ± 2.1 years (range, 0.83–5.25 years). Freedom from mechanical events at 5 years was 95.8 ± 6.1 in GA and 84.7 ± 5.3 in GB (p < 0.001).

The Posthorax vest is the latest technological generation of sternum support corsets [18]. It has been designed to stabilize the sternum following sternotomy so as to avoid excessive stress on the sternum wires during bone healing [17]. It differs from other previous vest designs because its structure is open in the front and is not based on a circumferential elastic band design making it less restrictive [18]. This open structure is also more hygienic, as it avoids compression and contamination of the skin wound. The non-elastic band structure avoids harmful continuous compression on the thorax and interference with respiratory effort and only provides support during excessive chest stress such as when coughing, mobilizing, or performing rehabilitation exercises [18]. In other words, the patient’s chest is free to move during breathing and is only supported during excessive or non-physiological movement, thus reducing the potential risk of respiratory complications. None of the patients who utilized the Posthorax support vest in our series developed post-operative pneumonia or any other kind of complications associated with its use. Our findings concerning the incidence of respiratory complications with Posthorax support vest adoption is not statistically significant. Statistically significant clinical advantages were observed in the group of patients that used the Posthorax support vest following sternotomy, such as less mechanical complications, better sternal healing, lower hospitalization, less pain and lower analgesic medication requirements, better comfort, and earlier mobilization and autonomy. These clinical improvements may be attributed to the improved sternum stability in group A that is provided by the Posthorax support vest without limitation on breathing and this can be translated in better patient comfort and mobility and lower incidence of mechanically induced sternum complications, but quite importantly in our “economic conscious” age can mean lower associated healthcare costs. Our findings are supported by other randomized studies from the literature [9, 18, 19]. However, these studies are multicentric and included infective and non-infective sternal complications and furthermore they did not do an extensive subgroup analysis on patients with a high risk for sternal complications. As recently reported by Heilmann et al. [19], superficial healing disorders occur in 3.3% of unselected patients after sternotomy for cardiac surgery, while 2.5% developed deep wound complications and 7.9% of them died in-hospital. No pathogen was identified and the wound appeared uninfected in 21% of all deep complications or 0.05% of all patients.

The data of the present study show that mechanical sternal complications play a significant role in the genesis of poststernotomy complications and confirm they remain a challenge to cardiac surgery so that more efforts seem mandatory to decrease their significant morbidity and the costs of prolonged treatment. The original design of this study allows to evaluate for the first time without bias the effectiveness of this new sternal support corset to prevent mechanical sternal complications, to reduce pain and hospitalization, and to increase the quality of life in the postoperative period.