Development of a new sternal dehiscence prediction scale for decision making in sternal closure techniques after cardiac surgery

Background After sternotomy, the spectrum for sternal osteosynthesis comprises standard wiring and more complex techniques, like titanium plating. The aim of this study is to develop a predictive risk score that evaluates the risk of sternum instability individually. The surgeon may then choose an appropriate sternal osteosynthesis technique that is risk- adjusted as well as cost-effective. Methods Data from 7.173 patients operated via sternotomy for all cardiovascular indications from 2008 until 2017 were retrospectively analyzed. Sternal dehiscence occurred in 2.5% of patients (n = 176). A multivariable analysis model examined pre- and intraoperative factors. A multivariable logistic regression model and a backward elimination based on the Akaike Information Criterion (AIC) a logistic model were selected. Results The model showed good sensitivity and specificity (area under the receiver-operating characteristic curve, AUC: 0.76) and several predictors of sternal instability could be evaluated. Multivariable logistic regression showed the highest Odds Ratios (OR) for reexploration (OR 6.6, confidence interval, CI [4.5–9.5], p < 0.001), obesity (body mass index, BMI > 35 kg/m2) (OR 4.23, [CI 2.4–7.3], p < 0.001), insulin-dependent diabetes mellitus (IDDM) (OR 2.2, CI [1.5–3.2], p = 0.01), smoking (OR 2.03, [CI 1.3–3.08], p = 0.001). After weighting the probability of sternum dehiscence with each factor, a risk score model was proposed scaling from − 1 to 5 points. This resulted in a risk score ranging up to 18 points, with an estimated risk for sternum complication up to 74%. Conclusions A weighted scoring system based on individual risk factors was specifically created to predict sternal dehiscence. High-scoring patients should receive additive closure techniques.

Sternal closure in patients with the high risk of sternal dehiscence

The objective was to evaluate the efficacy of sternal closure using the «double twist» technique.Methods and materials. The study included 37 patients with risk factors for sternal dehiscence (obesity, diabetes, chronic obstructive pulmonary disease). The patients were divided into 2 groups. In the first group (n=12), «double twist» technique was used. In patients of the second group (n=25), osteosynthesis was performed using standard technique (single wire ligatures). The efficacy of the «double twist» sternal closure was evaluated on the basis of clinical examination and multispiral computed tomography of the chest.Results. In the early postoperative period, the sternal dehiscence, which required re-operation was detected in 12 % after standard sternal closure. Sternum was stable in all of the patients of «double twist» group (p=0.211). No deep sternal infection was observed in both groups. In the follow-up (up to 6 months), there were no clinical and tomographic sings of delayed sternal dehiscence or infection in «double twist» group.Conclusions. Sternal closure using the «double twist» technique provides reliable fixation of the sternum in patients with the risk of its dehiscence.

Interlocking Multi-Twisted Wires Versus Interrupted Simple Sternal Wires for Closure of Median Sternotomy

Background: Although closure of a sternotomy incision is usually a simple procedure, failure to do so (sternal dehiscence) is a serious complication and is an independent factor that poses a high degree of morbidity or mortality after open heart surgery. Instability of the bone fragments can lead to complete sternal breakdown, sternal wound infection, and mediastinitis. The stainless-steel encircling wire used as either interrupted simple sutures or as figure of eight sutures is the current standard method of median sternotomy closure. Interlocking multi-twisted sternal wire closure is an alternative that provides rigid sternal fixation. We aim to identify the best method of sternal closure in order to implement it as a standardised protocol for our department. Methods: Two-hundred patients aged 18-70 years were undergoing cardiac surgeries at Ain Shams University hospitals. They were divided into two groups: Group I included 100 patients with sternal closure using simple wire, and group II included 100 patients with sternal closure using interlocking multi-twisted wires. The day 7, 1 month, and 3 months sternal instability, superficial wound infection, ventilation time, cross-clamp time, length of ICU stay, and length of hospital stay were analyzed. Results: The incidence of sternal instability on the 7th day, 1 month, and 3 months was significantly higher in the simple wire closure group (P < 0.05). However, incidence of superficial wound infection, length of ICU stay, and duration of mechanical ventilation were comparable between the two groups. Conclusion: The interlocking multi-twist is a safe, effective, and easily reproducible method for preventing sternal dehiscence.

What is the impact of a previously failed Robicsek repair in the subsequent treatment of sternal dehiscence with thermoreactive nitinol clips?

Background: In this study, we conducted a retrospective review of patients at our institution with noninfectious sternal dehiscence (NISD) after median sternotomy who received thermoreactive nitinol clips (TRNC) treatment during a 10-year period. We compared TRNC patients with and without history of failed Robicsek repair. The purpose of the study was to analyze the impact of previous Robicsek repair on the treatment of sternal dehiscence with TRCN. Methods: Between December 2009 and January 2020, out of 283 patients with NISD who underwent refixation, we studied 34 cases who received TRNC treatment. We divided these 34 cases into two groups: patients who had a previously failed Robicsek procedure before TRNC treatment (group A, n=11) and patients who had been directly referred to TRCN treatment (group B, n= 23). Results: Postoperative complication rate was significantly higher in group A (p=0.026). Hospitalization duration was significantly longer in group A due to the higher complication rate (p=0.001). Operative time was significantly shorter and blood loss was significantly lower in group B (p=0.001). Conclusion: The Robicsek procedure is considered an effective method in the treatment of NISD but, in case of its failure, subsequent TRNC treatment might become cumbersome in high-risk patients. In our study, a previously failed Robicsek procedure caused significantly higher morbidity and additional operative risk in later TRNC treatment of high-risk cases. Ultimately, we speculate that a direct TRNC treatment for NISD is favorable in high-risk patients.

Development of a New Sternal Dehiscence Prediction Scale for Decision Making in Sternal Closure Techniques After Cardiac Surgery

BackgroundAfter sternotomy, the spectrum for sternal osteosynthesis comprises standard wiring and more complex techniques, like titanium plating. The aim of this study is to develop a predictive risk score that evaluates the risk of sternum instability individually. The surgeon may then choose an appropriate sternal osteosynthesis technique that is risk- adjusted as well as cost-effective.MethodsData from 7.173 patients operated via sternotomy for all cardiovascular indications from 2008 until 2017 were retrospectively analyzed. Sternal dehiscence occurred in 2.5% of patients (n=176). A multivariable analysis model examined pre- and intraoperative factors. A multivariable logistic regression model and a backward elimination based on the Akaike Information Criterion (AIC) a logistic model were selected.ResultsThe model showed good sensitivity and specificity (area under the receiver-operating characteristic curve, AUC: 0.76) and several predictors of sternal instability could be evaluated. Multivariable logistic regression showed the highest Odds Ratios (OR) for reexploration (OR 6.6, confidence interval, CI [4.5-9.5], p <0.001), obesity (body mass index, BMI >35kg/m²) (OR 4.23, [CI 2.4-7.3], p<0.001), insulin-dependent diabetes mellitus (IDDM) (OR 2.2, CI [1.5-3.2], p=0.01), smoking (OR 2.03, [CI 1.3-3.08], p=0.001). After weighting the probability of sternum dehiscence with each factor, a risk score model was proposed scaling from -1 to 5 points. This resulted in a risk score ranging up to 18 points, with an estimated risk for sternum complication up to 74%.ConclusionsA weighted scoring system based on individual risk factors was specifically created to predict sternal dehiscence. High-scoring patients should receive additive closure techniques.

THEORETICAL MODEL OF STERNUM EXTERNAL FIXATION FUNCTIONING IN PHYSICAL THERAPY OF PATIENTS FOLLOWING CARDIAC SURGERY VIA STERNOTOMY

The purpose is to develop and analyze a theoretical model of sternum external fixation functioning as sternal precaution after cardiac surgery via sternotomy. Methods: theoretical modeling based on literature data. Results. The literature data, measuring the impact of sternum external fixation on the development of complications after cardiac surgery via sternotomy, do not present a proper report of the functioning mechanism or mechanical model of the interaction between the sternum and sternum external fixation. The first stage of theoretical model development included selecting the criteria based on the sternum anatomy, physiology of respiration, results of scientific research, which enabled to define key aspects of the theoretical model.The second stage included studying interaction of non-elastic SEF and sternum during a deep breath and a cough acting as main elements of inspiratory muscle training after cardiac surgeries; performing a similar algorithm of studying elastic type of SEF, which enabled to investigate and analyze preventive potential of SEF in relation to sternal dehiscence in the lateral direction. The third stage included the analysis of SEF restricting potential for anteroposterior stabilisation of the sternum. Since the use of sternum external fixation should not impede pulmonary function recovery after cardiac surgery and cannot restrict chest circumference increase with inhalation, sternum external fixation cannot properly function as sternal precaution when chest circumference is increased due to sternal edge dehiscence as well. The restricting effect of inelastic sternum external fixation will be possible only in case of a large dehiscence, when its size is bigger than the chest circumference increase during normal and deep breathing. Only when the circumference of inelastic sternum external fixation corresponds to the chest circumference after a full exhalation, the effect restricting dehiscence development will be possible. However, this condition is not practically feasible and does not comply with the need for pulmonary function recovery. As an example a barrel with iron rings that prevent it from expanding and emerging of dehiscence between the boards. However, this is not practically possible and is inconsistent with physiology of respiration. The restricting effect of elastic sternum external fixation will be possible in case the force of compression is greater than the force expanding the sternum during a cough, which will completely restrict inhaling and disable its practical use. The use of sternum external fixation must be biomechanically justified. The fact that the sternum is covered with soft tissues (muscles, which are joined with the bones of the sternum, shoulder blade and humerus; subcutaneous fat, which increases with excessive body weight) also reduces sternum external fixation effectiveness, as the existence of a soft and movable layer between the fixing parts and fixing means is a negative factor. On the other hand, dehiscence is a rare case among patients who do not use SEF. This confirms the priority of the sternal closure stability after sternotomy and the factors affecting it: the strength of bone tissue, the diameter of the wire, used during sternotomy, and the number of sutures. Conclusions. The theoretical model analyzed in this study confirms either the insignificant role of sternum external fixation or its complete absence in the prevention of sternal dehiscence in the lateral direction and anteroposterior displacement of sternum edges after sternotomy.

OUTCOMES AND SAFETY OF STERNAL CLOSURE USING NON-ABSORBABLE POLYESTER BRAIDED SUTURE: SINGLE TERTIARY CARE CENTER EXPERIENCE OF 5 YEARS.

Introduction: Median sternotomy is done as regular practice in cardiac surgery, which can lead to morbidity and mortality after sternal closure. Inappropriate sternal closure can lead to sternal dehiscence, sternal wound infection and mediastinitis. Aim: Efficacy and outcomes of sternal closure in adults weighing 2.5 kgs to 50 kgs using non-absorbable polyester braided suture. Methods: Total of 1091 patients underwent standard median sternotomy, weighing between 2.5 kgs to 50 kgs had sternal closure using non absorbable, braided, sterile, surgical suture composed of Poly ethylene terephthalate [polyester]. A retrospective analysis was done to review outcomes and complications related to this sternal closure technique. Results: Nineteen patients developed superficial surgical site infection and sternal sinus were seen in eight patients, whereas one patient had sternal dehiscence during immediate post-operative period. No sternal sutures were broken during the sternal closure and no case of mediastinitis was seen. Follow-up analyses of patients were done for 6 months after open heart surgery. Conclusion: Sternal closure using non-absorbable polyester braided suture is a safe and effective method with very less chances of post sternal wound complications in patients weighing between 2.5 kgs to 50 kgs.