Sternal instability after midline sternotomy

Optimizing Surgical Outcomes and the Role of Preventive Surgery: A Scoping Review

BACKGROUND

 Plastic and reconstructive surgeons are often presented with reconstructive challenges as a sequela of complications in high-risk surgical patients, ranging from exposure of hardware, lymphedema, and chronic pain after amputation. These complications can result in significant morbidity, recovery time, resource utilization, and cost. Given the prevalence of surgical complications managed by plastic and reconstructive surgeons, developing novel preventative techniques to mitigate surgical risk is paramount.

METHODS

 Herein, we aim to understand efforts supporting the nascent field of Preventive Surgery, including (1) enhanced risk stratification, (2) advancements in postoperative care. Through an emphasis on four surgical cohorts who may benefit from preventive surgery, two of which are at high risk of morbidity from wound-related complications (patients undergoing sternotomy and spine procedures) and two at high risk of other morbidities, including lymphedema and neuropathic pain, we aim to provide a comprehensive and improved understanding of preventive surgery. Additionally, the role of risk analysis for these procedures and the relationship between microsurgery and prophylaxis is emphasized.

RESULTS

 (1) medical optimization and prehabilitation, (2) surgical mitigation techniques.

CONCLUSION

 Reconstructive surgeons are ideally placed to lead efforts in the creation and validation of accurate risk assessment tools and to support algorithmic approaches to surgical risk mitigation. Through a paradigm shift, including universal promotion of the concept of "Preventive Surgery," major improvements in surgical outcomes may be achieved.

Sternal closure with sandwiched three-piece bioresorbable mesh reduces postoperative hemorrhage: a retrospective study

BACKGROUND

Median sternotomy is the most performed procedure in cardiac surgery; however, sternal displacement and bleeding remains a problem. This study aimed to investigate whether sternal reconstruction using a sandwiched three-piece bioresorbable mesh plate can prevent postoperative sternal displacement and bleeding more than a bioresorbable pin.

METHODS

Patients (n = 218) who underwent median sternotomy were classified according to whether a sandwiched three-piece bioresorbable mesh plate and wire cerclage (group M, n = 109) or a bioresorbable pin and wire cerclage (group P, n = 109) were used during sternal reconstruction. The causes of postoperative sternal displacement and bleeding with computed tomography data were analyzed and compared between the groups.

RESULTS

The preoperative patient characteristics did not significantly differ between the groups. However, the evaluation of sternal and substernal hematoma on postoperative day 5 using computed tomography showed sternal displacement in 4 (4%) and 22 (20%) patients, and substernal hematoma in 17 (16%) and 41 (38%) patients in groups M and P, respectively; this difference was significant. Furthermore, the amount of bleeding at 6 h postoperatively was lower in group M than in group P (235 ± 147 vs. 284 ± 175 mL, p = 0.0275). Chest reopening, intubation time, and length of intensive care unit and hospital stays did not differ between the groups. The evaluation of substernal hematoma based on computed tomography yielded a significantly lower for group M than for group P, revealing that the mesh plate was an independent predictor of substernal hematoma prevention.

CONCLUSION

Sternal fixation with a three-piece bioresorbable mesh plate could prevent postoperative sternal displacement, bleeding, and substernal hematoma more than sternal fixation with a pin.

Development of novel waxy bone haemostatic agents composed of biodegradable polymers with osteogenic-enhancing peptides in rabbit models

OBJECTIVES

The use of bone wax (BW) is controversial for sternal haemostasis because it increases the risk of wound infection and inhibits bone healing. We developed new waxy bone haemostatic agents made from biodegradable polymers containing peptides and evaluated them using rabbit models.

METHODS

We designed 2 types of waxy bone haemostatic agents: peptide wax (PW) and non-peptide wax (NPW), which used poly(ε-caprolactone)-based biodegradable polymers with or without an osteogenesis-enhancing peptide, respectively. Rabbits were randomly divided into 4 groups based on treatment with BW, NPW, PW or no treatment. In a tibial defect model, the bleeding amount was measured and bone healing was evaluated by micro-computed tomography over 16 weeks. Bone healing in a median sternotomy model was assessed for 2 weeks using X-ray, micro-computed tomography, histological examination and flexural strength testing.

RESULTS

The textures of PW and NPW (n = 12 each) were similar to that of BW and achieved a comparable degree of haemostasis. The crevice area of the sternal fracture line in the BW group was significantly larger than that in other groups (n = 10 each). The PW group demonstrated the strongest sternal flexural strength (n = 10), with complete tibial healing at 16 weeks. No groups exhibited wound infection, including osteomyelitis.

CONCLUSIONS

Waxy biodegradable haemostatic agents showed satisfactory results in haemostasis and bone healing in rabbit models and may be an effective alternative to BW.

Novel hardening bone putty enhances sternal closure and accelerates postoperative recovery

OBJECTIVES

Regaining and maintaining sternal stability are key to recovery after cardiac surgery and resuming baseline quality of life. Montage (ABYRX) is a moldable, calcium phosphate-based putty that adheres to bleeding bone, hardens after application, and is resorbed and replaced with bone during the remodeling process. We evaluate the feasibility, safety, and efficacy of enhanced sternal closure with this novel putty to accelerate recovery in patients after sternotomy.

METHODS

A single-center, single-blinded, randomized controlled trial was performed (NCT03365843). Patients undergoing elective cardiac surgery via sternotomy received sternal closure with either Montage bone putty and wire cerclage (enhanced sternal closure; n = 33) or wire cerclage alone (control; n = 27). Standardized patient-reported outcomes assessed health-related quality of life (EQ-5D Index) and physical disability (Health Assessment Questionnaire). A Likert-type 11-point scale quantified pain. Spirometry assessed respiratory function. Patients reached 6-week follow-up, with 1-year follow-up for safety end points.

RESULTS

There were no device-related adverse events. Enhanced sternal closure improved physical functional recovery (reduced Healthcare Index and Quality) and quality of life (increased EQ-5D Index) at day 5/discharge, week 2, and week 4. Enhanced sternal closure reduced incisional pain while resting, breathing, sleeping, and walking at day 5/discharge. Enhanced sternal closure reduced chest wall and back pain at day 3 and day 5 discharge. A higher proportion of patients with enhanced sternal closure recovered to 60% of their baseline forced vital capacity by day 5/discharge. Enhanced sternal closure shortened hospital stay.

CONCLUSIONS

Enhanced sternal closure improves and accelerates postoperative recovery compared with conventional wire closure. Earlier discharge may provide substantial cost benefits for the healthcare system.

A prospective randomized controlled study to assess the effectiveness of super FIXSORB WAVE® for sternal stabilization after sternotomy

BACKGROUND

We developed a new sternal fixation device, Super FIXSORB WAVE®, a corrugated plate made of u-HA/PLLA, to improve sternal stability after sternotomy. This present study aimed to evaluate the new device clinically.

METHODS

This prospective, single-blinded, multicenter trial randomized 69 patients to either wire cerclage only (group C, n = 30) or wire cerclage plus Super FIXSORB WAVE® (group W, n = 39). The primary endpoint was a degree of sternal displacement at six months. Displacement of the sternal halves in the anteroposterior and lateral directions was measured using computed tomography horizontal section images at the third costal and fourth intercostal levels. The secondary endpoints were sternal pain and quality-of-life over 6 months.

RESULTS

Group W showed significantly reduced sternal anteroposterior displacement at both the third costal (0 [0-1.9] mm vs. 1.1 [0-2.1] mm; P = 0.014) and fourth intercostal (0 [0-1.0] mm) vs. 1.0 [0-1.8] mm; P = 0.015) levels than group C. In group W, lateral displacement was suppressed without a significant increase from 2 weeks to 6 months, while it increased in group C. There was no significant difference in postoperative sternal pain and quality-of-life between the two groups. No adverse events, such as infection, inflammation, or foreign body reaction, were observed with this device.

CONCLUSIONS

Using Super FIXSORB WAVE®, sternal displacement was significantly suppressed in both the anteroposterior and lateral directions. The use of this device results in safe and easy sternal reinforcement without any adverse events, and sternal healing can be accelerated.

CLINICAL TRIAL REGISTRY NUMBER

This study was registered in the Japan Registry of Clinical Trials (February 21, 2019; jRCTs032180146).

Biomechanical comparison of canine median sternotomy closure using suture tape and orthopedic wire cerclage

OBJECTIVE

To compare the mechanical properties of suture tape and orthopedic wire cerclage in an ex vivo canine median sternotomy model.

STUDY DESIGN

Ex vivo.

ANIMALS

Twelve large-breed canine cadaveric sternums.

METHODS

Median sternotomies were performed, leaving the manubrium intact. The specimens were randomly assigned to group W (20-gauge stainless steel orthopedic wire cerclage in a figure-of-eight pattern) or group ST (suture tape in a figure-of-eight pattern). Each specimen was laterally distracted until failure using an electrodynamic materials-testing system.

RESULTS

No differences were observed for displacement, yield load, maximum load, implant failure between the groups. The orthopedic wire construct was stiffer than the suture tape construct.

CONCLUSION

Suture tape was biomechanically similar to orthopedic wire cerclage for sternotomy closure in dogs, although wire constructs were stiffer.

CLINICAL SIGNIFICANCE

Suture tape may represent an alternative to cerclage wire for sternotomy closure in dogs. Additional studies evaluating its clinical use are needed.

Comparison of Two Techniques Performing the Supine-to-Sitting Postural Change in Patients with Sternotomy

Patients with sternotomy are advised to follow sternal precautions to avoid the risk of sternal complications. However, there are no standard recommendations, in particular to perform the supine-to-sitting postural change, where sternal asymmetrical force may be applied. The aim of this study was to compare the rotational movement and the use of a tied rope (individual device for supine-to-sitting, "IDSS") to perform the supine-to-sitting postural change. A total of 92 patients (26% female) admitted to a rehabilitative post-surgery ward with sternotomy were assessed for sternal instability. Levels of pain and perceived effort during the two modalities of postural change and at rest were assessed. Patients reported higher values of pain and perceived effort (both p < 0.0005) during rotational movement with respect to the use of the IDSS. Moreover, patients with sternal instability (14%) and female patients with macromastia (25%) reported higher pain than those stable or without macromastia (both p < 0.05). No other risk factors were associated with pain. Thus, the IDSS seems to reduce the levels of pain and perceived effort during the supine-to-sitting postural change. Future studies with quantitative assessments are required to suggest the adoption of this technique, mostly in patients with high levels of pain or with sternal instability.

Non-infectious sternal dehiscence after coronary artery bypass surgery

Introduction

Non-infectious sternal dehiscence (NISD) is a known complication following coronary artery bypass grafting (CABG), with previous studies estimating an incidence of 0.4–1% of surgeries. We aimed to study the incidence of NISD together with short- and long-term outcomes in a whole-nation cohort of patients.

Materials and methods

A retrospective study on consecutive CABG patients diagnosed with NISD at Landspitali from 2001 to 2020. Patients diagnosed with infectious mediastinitis (n = 20) were excluded. NISD patients were compared to patients with an intact sternum regarding patient demographics, cardiovascular risk factors, intra- and postoperative data, and estimated overall survival. The median follow-up was 9.5 years.

Results

Twenty out of 2280 eligible patients (0.88%) developed NISD, and the incidence did not change over the study period (p = 0.98). The median time of diagnosis was 12 days postoperatively (range, 4–240). All patients were re-operated using a Robicsek-rewiring technique, with two cases requiring a titanium plate for fixation. Patients with NISD were older, had a higher BMI and EuroSCORE II, lower LVEF, and more often had a history of COPD, MI, and diabetes compared to those without NISD. Length of stay was extended by 15 days for NISD patients, but short and long-term survival was not statistically different between the groups.

Conclusions

The incidence of NISD was low and in line with previous studies. Although the length of hospital stay was extended, both short- and long-term survival of NISD patients was not significantly different from patients with an intact sternum.

SAfety and Feasibility of EArly Resistance Training After Median Sternotomy: The SAFE-ARMS Study

OBJECTIVE

The purpose of this study was to determine the safety and feasibility of subacute upper limb resistance exercise on sternal micromotion and pain and the reliability of sternal ultrasound assessment following cardiac surgery via median sternotomy.

METHODS

This experimental study used a pretest-posttest design to investigate the effects of upper limb resistance exercise on the sternum in patients following their first cardiac surgery via median sternotomy. Six bilateral upper limb machine-based exercises were commenced at a base resistance of 20 lb (9 kg) and progressed for each participant. Sternal micromotion was assessed using ultrasound at the mid and lower sternum at 2, 8, and 14 weeks postsurgery. Intrarater and interrater reliability was calculated using intraclass correlation coefficients (ICCs). Participant-reported pain was recorded at rest and with each exercise using a visual analogue scale.

RESULTS

Sixteen adults (n = 15 males; 71.3 [SD = 6.2] years of age) consented to participate. Twelve participants completed the study, 2 withdrew prior to the 8-week assessment, and 2 assessments were not completed at 14 weeks due to assessor unavailability. The highest median micromotion at the sternal edges was observed during the bicep curl (median = 1.33 mm; range = -0.8 to 2.0 mm) in the lateral direction and the shoulder pulldown (median = 0.65 mm; range = -0.8 to 1.6 mm) in the anterior-posterior direction. Furthermore, participants reported no increase in pain when performing any of the 6 upper limb exercises. Interrater reliability was moderate to good for both lateral-posterior (ICC = 0.73; 95% CI = 0.58 to 0.83) and anterior-posterior micromotion (ICC = 0.83; 95% CI = 0.73 to 0.89) of the sternal edges.

CONCLUSION

Bilateral upper limb resistance exercises performed on cam-based machines do not result in sternal micromotion exceeding 2.0 mm or an increase in participant-reported pain.

IMPACT

Upper limb resistance training commenced as early as 2 weeks following cardiac surgery via median sternotomy and performed within the safe limits of pain and sternal micromotion appears to be safe and may accelerate postoperative recovery rather than muscular deconditioning.

Review of Biomechanical Studies and Finite Element Modeling of Sternal Closure Using Bio-Active Adhesives

The most common complication of median sternotomy surgery is sternum re-separation after sternal fixation, which leads to high rates of morbidity and mortality. The adhered sternal fixation technique comprises the wiring fixation technique and the use of bio-adhesives. Adhered sternal fixation techniques have not been extensively studied using finite element analysis, so mechanical testing studies and finite element analysis of sternal fixation will be presented in this review to find the optimum techniques for simulating sternal fixation with adhesives. The optimal wiring technique should enhance bone stability and limit sternal displacement. Bio-adhesives have been proposed to support sternal fixation, as wiring is prone to failure in cases of post-operative problems. The aim of this paper is to review and present the existing numerical and biomechanical sternal fixation studies by reviewing common sternal closure techniques, adhesives for sternal closure, biomechanical modeling of sternal fixation, and finite element modeling of sternal fixation systems. Investigating the physical behavior of 3D sternal fixation models by finite element analysis (FEA) will lower the expense of conducting clinical trials. This indicates that FEA studies of sternal fixation with adhesives are needed to analyze the efficiency of this sternal closure technique virtually.

Comparison of polyetheretherketone cables and stainless steel wires for sternal fixation after median sternotomy

Objective

To compare the sternal fixation effect of a polyetheretherketone (PEEK) cable product and stainless steel wire after median sternotomy.

Methods

A multicentre retrospective clinical trial was conducted in patients that underwent median sternotomy for a range of surgical reasons. The sternum was fixed using PEEK sternal cables in the experimental group and stainless steel wires in the control group. The general patient state, product manoeuvrability, bone and wound healing state and blood test results were evaluated at seven visits during the preoperative, surgical and follow-up periods.

Results

A total of 108 patients (54 in each group) were included in the analysis at the final 180-day follow-up. The sternum was successfully closed using PEEK cables or steel wires in all patients and all healed well. No pathological changes were found on the X-ray imaging. Computed tomography imaging confirmed ideal fracture healing. No significant difference was found between the experimental group and the control group in outcomes.

Conclusion

PEEK cables are easy to implant and show desirable effectiveness in sternal fixation without any observed side-effects.

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. The purpose of the study was to analyze the impact of previous Robicsek repair on the later treatment of sternal dehiscence with TRCN to establish which method was better in high-risk patients with NISD.

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). High-risk patients were defined as those having three or more risk factors.

RESULTS

Postoperative complication rate was significantly higher in group A (p = .026). Hospitalization duration was significantly longer in group A due to the higher complication rate (p = .001). Operative time was significantly shorter and blood loss was significantly lower in group B (p = .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, additional operative risk and lower success rate 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

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.

Safety and feasibility of rigid fixation by SternaLock Blu plates during the modified Ravitch procedure: a pilot study

Background

Patients with anterior chest wall deformities unsuitable for minimally invasive repair are commonly treated by the modified Ravitch procedure. Although rigid plate fixation of the sternal osteotomy has previously shown to facilitate adequate sternal union, its use is troubled by an implant removal rate of up to 23% due to local complaints or complications associated with bulky plates. In contrast, the use of thinner and therefore biomechanically weaker plates may result in a higher incidence of non- or mal-union. In this pilot study, we evaluate the feasibility, efficacy and safety of rigid sternal fixation by thin pre-shaped anatomical locking plates during the modified Ravitch procedure.

Methods

Between June 2018 and December 2019, all consecutive patients who underwent anterior chest wall deformity repair by the modified Ravitch procedure in our tertiary referral centre were included. Data was collected retrospectively. All pectus types were included. The sternal osteotomy was fixated using thin SternaLock Blu plates. Patients were followed for at least one year.

Results

Nine patients were included. The group consisted of six male and three female patients, with a median age of 20 years [interquartile range (IQR), 16–35 years]. Median duration of follow-up was 25 months (IQR, 16–28 months). No intraoperative complications occurred. No patients presented with symptomatic non- or mal-union. Plate removal was performed in one patient for atypical pain without relief. No other postoperative complications occurred.

Conclusions

Based on these pilot results, thin SternaLock Blu plates are deemed to be safe and effective in providing adequate rigid fixation of the sternal osteotomy during the modified Ravitch procedure. Compared to literature, the need for plate removal within 25 months after surgery was reduced.

In vivo analysis of a proprietary glass-based adhesive for sternal fixation and stabilization using rabbit and sheep models

Wire cerclage remains the standard method of care for sternal fixation, following median sternotomy, despite being beset with complications. An emerging treatment option has been to augment the wires with an adhesive. A patented ionomeric glass (mole fraction: SiO2:0.48, ZnO:0.36, CaO:0.12, SrO:0.04) has been used to formulate GPC+, a glass polyalkenoate cement (GPC), by mixing it with poly(acrylic) acid (PAA) and de-ionized water. In a human cadaver study, this material, when applied with wire cerclage, was able to significantly reduce sternal instability. However, the material has yet to be tested in pertinent animal models. Here, after a series of physical and mechanical tests to confirm suitability of the experimental material for implantation, three samples of GPC+ were implanted in either the tibia or femur of three different rabbits, alongside sham defects, for two different time modalities. A further seven samples of GPC+ and one poly(methyl methacrylate) control (PMMA) were implanted in either the tibia or femur of two different sheep. The sheep containing the PMMA was sacrificed at 8 weeks and the other at 16 weeks, to evaluate time dependent biological response. Upon sacrifice, microCT images were acquired and histology slides prepared for analysis. All three GPC+ samples implanted in the rabbit model, for the two time modalities, were characterized by minimal bone resorption along with a mild inflammatory response. Five of the seven GPC+ materials implanted in the sheep model (all three implanted for 8 weeks and two of those implanted for 16 weeks) were associated with mild to moderate immune response, comparable to that observed with PMMA, as well as mild bone resorption. The remaining two GPC + materials (implanted in the sheep model for 16 weeks) exhibited no bone resorption or inflammatory response and appeared to stimulate increased bone density at the implant site. These results suggest that GPC + can be a viable bone adhesive for use in hard tissue applications such as sternal fixation and stabilization. Experiments performed to synthesize & test Sr-doped glass adhesive for sternal fixation. (1) Sr-doped ionomeric glass fired, ground down and mixed with aqueous polyacrylic acid to produce the adhesive. (2) Adhesive characterized and tested by a suite of laboratory-based tests to ensure suitability for implantation. (3) Adhesive implanted into a rabbit model (distal femur, 12 weeks post implantation) where micro-CT images confirmed an excellent bone/cement interface, no evidence of bone resorption and some bone remodelling. (4) Adhesive subsequently implanted into a sheep model; at 16-weeks, a continuous bone-adhesive interface is seen suggesting no bone resorption. There was an increase in the peri-implant radiodensity, suggesting enhanced mineral content of the bone surrounding the GPC+ implant.

Prevention of Sternal Wound Infections in Women Using an External Sternum Fixation Corset

Purpose: Deep sternal wound infection (DSWI) and mediastinitis are devastating complications after median sternotomy. Previous studies demonstrated an effective prevention of sternal wound infection (SWI) using an external sternal corset in high-risk cardiac surgery patients. The aim of this study is to assess the preventive effect of the Stern-E-Fix corset in high-risk poststernotomy female patients.

Methods: A total of 145 high-risk female patients undergoing cardiac surgery through median sternotomy were retrospectively analyzed. Patients were divided into group A (n = 71), who received the Stern-E-Fix corset (Fendel & Keuchen GmbH, Aachen, Germany), and group B (n = 74), who received the elastic thorax bandage (SanThorax) postoperatively for 6 weeks. The mean follow-up period was 12 weeks.

Results: Incidence of SWI was 7% in group A vs. 17.6% in group B (p = 0.025). One patient presented with DSWI in group A vs. seven patients in group B (p = 0.063). No patient developed mediastinitis in group A vs. four patients in group B (p = 0.121). In all, 4.2% of group A patients required operative wound therapy vs. 16.2% of group B patients (p = 0.026). The length of hospital stay was significantly longer in group B (p = 0.006).

Conclusion: Using an external supportive sternal corset (Stern-E-Fix) yields a significantly better and effective prevention against development of sternal dehiscence, DSWI, and mediastinitis in high-risk poststernotomy female patients.

Sternal closure with single compared with double or figure of 8 wires in obese patients following cardiac surgery: A systematic review and meta-analysis

OBJECTIVES

Sternal instability and wound infections are major causes of morbidity following cardiac surgery, which is further amplified in high risk patients that include diabetics and patients with high body mass index (BMI). We compare the different outcomes of different sternal wire closure techniques following median sternotomy for cardiac surgery in obese patients.

METHODS

A comprehensive electronic literature search was undertaken according to PRISMA guidelines from inception to July 2020 to identify all published data comparing single wire sternal closure to either double wire or figure-of-8 techniques following median sternotomy for cardiac surgery in obese patients, defined as a BMI ≥ 30.

RESULTS

Eight studies met the final inclusion criteria; single wire versus double wire sternal closure (n = 2) and single wire versus figure-of-8 wire closure (n = 6). Higher rate of sternal instability was noted in single wire versus double wire closure (22/150 [14.7%] patients vs. 6/150 [4%] patients, p = 0.003, odd ratio [OR] 0.25 [95% confidence interval [CI] 0.10-0.63]). Similarly, sternal instability was higher in single wire vs figure-of-8 wire closure technique (33/2422 [1.3%] vs. 11/8035 [0.1%], p = 0.04 OR 0.30 [95% CI, 0.09-0.96]), respectively.

CONCLUSION

There is benefit in the use of either double or figure-of-8 sternal wire closure techniques over single wire closure in terms of sternal instability. However, as the studies were limited, larger scale comparative studies are required to provide a solid evidence base for choosing the optimal sternal closure technique in this high risk group of patients.

[Additional vascularization of the omental flap using mammary-gastroepiploic bypass grafting in the treatment of deep sternal wound infection]

Incidence of postoperative sternomediastinitis depends on various risk factors and makes up 8%. Surgical debridement with local management of the wound are used to achieve wound sterility. In some cases, sternectomy or subtotal sternal resection are performed for total sternal osteomyelitis with osteoporotic bone and multiple fractures. This procedure results an extensive bone defect. The final stage is anterior chest wall reconstruction. The most popular method is wound closure with autologous muscle or omental flaps. The authors describe a patient with sternomediastinitis who underwent staged treatment. At the final stage, subtotal sternectomy with simultaneous omentoplasty were performed. Additionally, mammary-gastroepiploic bypass grafting with right internal mammary artery and right gastroepiploic artery was carried out for additional vascularization of the omental flap. We found no similar surgery for sternomediastinitis in the literature. Long-term treatment outcome was followed-up (>50 months of relapse-free period and good quality of life).

The Novel Technique of Sternal Closure With Absorbable Mesh for Osteoporotic Patients

After a median sternotomy, sternal instability can result in sternal infection. The usual sternal closure with stainless steel wires may result in sternal instability, especially in osteoporotic patients. An absorbable mesh (Super-FIXSORB-MX®40, Takiron Co Ltd, Osaka, Japan) for reinforcing the sternum has become commercially available. This paper reports a modified sternal closure procedure using this absorbable mesh in combination with heavy braided Polydiaxanon (PDS cord®, Ethicon, Inc., Somerville, NJ, USA) for osteoporotic patients.

Recent developments in controlling sternal wound infection after cardiac surgery and measures to enhance sternal healing

One of the major risks of cardiac surgery is the occurrence of infection at the sternal wound site. Sternal wound infections are primarily classified into superficial infection and deep sternal wound infection or mediastinitis. A patient is diagnosed with mediastinitis if microorganisms are present in their mediastinal tissue/fluid or with the observation of sternal wound infection during operation and with characteristic symptoms including chest pain, fever, and purulent drainage from the mediastinum. It is usually caused by Staphylococcal organisms in 75.8% of cases and the rest is caused by gram-negative bacteria. Currently, in cardiac surgery, hemostasis is achieved using electrocautery and bone wax, and the sternum is closed using wire cerclage. Several studies show that bone wax can act as a nidus for initiation of infection and the oozing blood and hematoma at the site can promote the growth of infectious organisms. Many research groups have developed different types of biomaterials and reported on the prevention of infection and healing of the sternum. These materials are reported to have both positive and negative effects. In this review, we highlight the current clinical practices undertaken to prevent infection and bleeding as well as research progress in this field and their outcomes in controlling bleeding, infection, and enhancing sternal healing.

Does the use of locking plates or mesh and wires influence the risk of symptomatic non-union of the sternal osteotomy after modified Ravitch?

Background

Patients with pectus excavatum which is unsuitable for minimally invasive repair are usually treated by modified Ravitch procedure. For fixation of the sternal osteotomy, mesh and wires are mostly used. To decrease non-union risk, we introduced a technique with double locking plate fixation of the osteotomy and compared this to fixation using mesh and wires.

Methods

Patients undergoing a modified Ravitch procedure for pectus excavatum between 2006 and 2016 were included. From 2006 to 2012, the sternum was fixated with mesh and wires. From 2012 to 2016, locking compression plates (LCP) were used. Baseline parameters, symptomatic non-union and total number of complications were retrospectively compared. Statistical analysis was performed using Mann-Whitney or Fisher’s exact test. Data are presented as means +/− SD.

Results

Forty-four patients were included. In 18 patients, the sternum was fixed with mesh and wires, in 26 patients with LCP. Mean follow-up was 35 months in the mesh and 30 months in the LCP group, P=0.71. Haller index was similar in both groups (mesh 3.8±1.3 vs. LCP 3.9±1.1, P=0.81). Symptomatic non-union occurred in 17% (n=3) in the mesh group and did not occur after LCP, P=0.062. Total number of complications was 33% (n=6) in the mesh group and 15% (n=4) after LCP, P=0.27.

Conclusions

After modified Ravitch procedure, union of the sternal osteotomy is challenging. In this retrospective cohort study, a lower incidence of symptomatic non-union was observed after fixation of the sternum with LCPs, with a trend towards statistical significance.

Total arterial multivessels minimal invasive direct coronary artery bypass grafting via left minithoracotomy

BACKGROUND

Minimal Invasive Direct Coronary Artery Bypass Surgery (MIDCAB) is becoming popular and an important armamentarium for cardiac surgeons. We aimed to evaluate the result of MIDCAB total arterial revascularization.

METHODS

We have evaluated 216 patients who underwent MIDCAB multivessel total arterial revascularization through a left anterolateral mini thoracotomy. LIMA harvested in every patient, RIMA or radial artery used as second conduit. LIMA-RIMA Y or LIMA-RADIAL Y was made to accomplish multivessels total arterial revascularization. Post-operative graft patency was evaluated in all patients by CT coronary angiography at 6 months following discharge.

RESULTS

Mean age of patients was 52.5 ± 9.8 years. Average number of anastomosis performed were 2.34 ± 0.75. Multivessels total arterial CABG was accomplished in all individuals. There was no mortality or deep wound infection. Re-exploration was done in two patients for bleeding. In one patient emergency CPB was required. Average ICU and hospital stay was 1.52 ± 0.77 and 4.92 ± 1.46 days, respectively. Patients were mobilized earlier due to less pain. Wound healing of anterolateral thoracotomy was faster. In the follow up CT angiography 100% of the LIMA grafts were patent.

CONCLUSIONS

Multivessels total arterial MIDCAB can be accomplished safely in selected individuals. RIMA can be harvested in long standing diabetic patients with no concern for sternal wound healing. MIDCAB patients experience better cosmetics and early return to daily activities.

Sternal Wound Complications: Results of Routine Use of Negative Pressure Wound Therapy

INTRODUCTION

Negative pressure wound therapy (NPWT) has significantly improved outcomes in individuals with superficial and deep sternal wound dehiscence (SWD). We report our experience with NPWT to evaluate factors influencing effectiveness, duration of treatment and postoperative hospital stay.

METHODS

We reviewed 92 patients with postoperative SWD following a median sternotomy. Patients were divided into 2 groups: those with a superficial SWD (Group 1; 72, 78%) and those with a deep SWD (Group 2; 20, 28%). Group 1 was further divided into 3 subgroups based on NPWT duration.

RESULTS

In both groups, none of the preoperative characteristics examined showed a significant association with longer NPWT duration. In Group 2, there was a trend for postoperative bleeding and neurological complications to be associated with longer treatment duration. In the entire series, staph infection resulted a weak predictor of NPWT duration. In each Group 1 subgroup and in Group 2, treatment days were compared with duration of hospitalization until discharge. Mean post-NPWT hospital stay was 6 days in subgroup 1, 12 days in subgroup 2 and 20 days in subgroup 3 (P<0.0001). At a median 3-year follow-up, there were 4 late deaths, none related to wound complications. No cases of SWD recurrence were observed.

CONCLUSION

Our results confirm the effectiveness of NPWT in SWD management, while excessive treatment duration might have a negative impact on the length of hospital stay. Further studies are needed to define an optimal use of NPWT protocol.

Wearable Sensor-Based Digital Biomarker to Estimate Chest Expansion During Sit-to-Stand Transitions-A Practical Tool to Improve Sternal Precautions in Patients Undergoing Median Sternotomy

Sternal precautions are a universal part of the discharge education for post-sternotomy patients to reduce the risk of sternal complications. However, they are always designed based on physical therapists' or surgeons' subjective judgment without any objective evidence. Thus, they could be overly restrictive to hinder the patients' recovery, physically and psychologically. To fill this gap, this paper proposes a digital biomarker to estimate chest expansion during sit-to-stand transitions based on wearable inertial sensing and data fusion technologies. First, we carried out bench tests to evaluate the reliability of the digital biomarker to represent relative sensor rotation. We also verified effectiveness of this digital biomarker to detect subtle skin extension in proactive chest expansion trials by 11 healthy volunteers. Then, we measured the digital biomarker during sit-to-stand transitions with different strategies and some daily routine activities (walking, sitting, and standing) performed by the healthy volunteers and 22 post-sternotomy patients. The comparison between these measurements evaluated the effectiveness of several known guidelines of sternal precautions for sit-to-stand transitions. The results showed that first, pushing up from a chair by taking support from armrests induced larger chest expansion ( p = 0.009 ) compared with sit-to-stand transition while keeping the arms relaxed; second, crossing the arms or hugging a pillow can help reduce chest expansion ( ) compared with keeping the arms relaxed during sit-to-stand transitions; third, pushing up while taking support from a frontal support (e.g., table or walker) induced the same level of chest expansion ( ) as that during sit-to-stand transition while keeping the arms relaxed.

An Evidence-Based Perspective on Movement and Activity Following Median Sternotomy

Cardiac surgery via median sternotomy is performed in over 1 million patients per year worldwide. Despite evidence, sternal precautions in the form of restricted arm and trunk activity are routinely prescribed to patients following surgery to prevent sternal complications. Sternal precautions may exacerbate loss of independence and prevent patients from returning home directly after hospital discharge. In addition, immobility and deconditioning associated with restricting physical activity potentially contribute to the negative sequelae of median sternotomy on patient symptoms, physical and psychosocial function, and quality of life. Interpreting the clinical impact of sternal precautions is challenging due to inconsistent definitions and applications globally. Following median sternotomy, typical guidelines involve limiting arm movement during loaded lifting, pushing, and pulling for 6 to 8 weeks. This perspective paper proposes that there is robust evidence to support early implementation of upper body activity and exercise in patients recovering from median sternotomy while minimizing risk of complications. A clinical paradigm shift is encouraged, one that encourages a greater amount of controlled upper body activity, albeit modified in some situations, and less restrictive sternal precautions. Early screening for sternal complication risk factors and instability followed by individualized progressive functional activity and upper body therapeutic exercise is likely to promote optimal and timely patient recovery. Substantial research documenting current clinical practice of sternal precautions, early physical therapy, and cardiac rehabilitation provides support and the context for understanding why a less restrictive and more active plan of care is warranted and recommended for patients following a median sternotomy.

A device for measuring sternal bone connectivity using vibration analysis techniques

Objectives:

Stability of bone splitting sternotomy is essential for normal healing after open cardiac surgery. Mechanical vibration transmittance may offer a means for early detection of separation of bone (diastasis) in the sternotomy and prevent further complications. This article describes the technical implementation and validation of vibration analysis–based prototype device built for measuring sternal bone connectivity after sternotomy.

Methods:

An in-house built measurement system, sternal vibration device, consisting of actuator, sensor, and main controller and signal acquisition unit was designed and manufactured. The system was validated, and three different test settings were studied in mockups (polylactide rods in ballistic gel) and in two human sternums: intact, stable wire fixation, and unstable wire fixation with a gap mimicking bone diastasis. The transmittance of vibration stimulus across the median sternotomy was measured.

Results:

The validation showed that the force produced by the actuator was stable, and the sensor could be calibrated to precisely measure the acceleration values. The vibration transmittance response to material cut and sternotomy was evident and detectable in the 20 Hz to 2 kHz band. The transmittance decreased when the connectivity between the sternal halves became unstable. The trend was visible in all the settings.

Conclusion:

Technical solutions and description of validation process were given. The device was calibrated, and the vibration transmittance analysis differentiated intact and cut polylactide rod. In the sternum, intact bone, wire fixation with exact apposition, and with a gap were identified separately. Although further studies are needed to assess the accuracy of the method to detect different levels of diastases, the method appears to be feasible.

[Combined thoracoplasty using titanium mesh implant in patients with total sternal instability following postoperative sternomediastinitis]

OBJECTIVE

To analyze the results of chest wall reconstruction with titanium mesh implant in patients with total sternal instability following postoperative sternomediastinitis.

MATERIAL AND METHODS

There were 100 patients with total sternal instability for the period from January 2016 to December 2018. Median of age was 62 (58; 68) years. Male/female ratio was 82/18. All patients were treated in accordance with standardized protocol. Postoperative complications were assessed using Clavien-Dindo scale. Staged surgical treatment including one or more debridement procedures before the final thoracoplasty was performed in 62 (62%) out of 100 patients. Aseptic sternal instability was observed in 38 patients.

RESULTS

Follow-up period ranged from 3 weeks to 35 months after the final thoracoplasty. Complicated postoperative period occurred in 15 (15%) out of 100 patients (95% CI 9.3-23.3). One patient died in 9 days after surgery from acute heart failure. Complications without need for redo surgery, postoperative wound suppuration and seroma were noted in 3 patients. Redo surgery was required in 11 patients due to postoperative wound suppuration, eventration after thoracoomentoplasty, intermuscular hematoma and delayed divergence of major pectoral muscles. Removal of mesh implant was performed in 1 out of 100 patient (95% CI 0.2-5.5) in 7 days after surgery due to suppuration. There was no recurrent sternal instability within 30 days.

CONCLUSION

Anterior chest wall reconstruction using titanium mesh implant is an effective and safe procedure in patients with postoperative sternal instability following postoperative sternomediastinitis.

Sternal wound closure in the current era: the need of a tailored approach

OBJECTIVE

Median sternotomy remains the most common access to perform cardiac surgery procedures. However, the experience of the operating surgeon remains a crucial factor during sternal closure to avoid potential complications related to poor sternal healing, such as mediastinitis. Considering the lack of major randomized controlled trials and the heterogeneity of the current literature, this narrative review aims to summarize the different techniques and approaches to sternal closure with the aim to investigate their reflections into clinical outcomes and to inform the choice on the most effective closure method after median sternotomy.

METHODS

A literature search through PubMed, Embase, EBSCO, Cochrane database of systematic reviews, and Web of Science from its inception up to April 2019 using the following search keywords in various combinations: sternal, sternotomy, mediastinitis, deep sternal wound infection, cardiac surgery, closure.

RESULTS

Single wire fixation methods, at present, seems the most useful method to perform sternal closure in routine patients, although patients with a fragile sternum might benefit more from a figure-of-eight technique. In high-risk patients (e.g. chronic pulmonary disease, obesity, bilateral internal mammary artery harvesting, diabetes, off-midline sternotomy), rigid plate fixation is currently the most effective method, if available; alternatively, weave techniques could be used.

CONCLUSION

The choice among the sternal closure techniques should be mainly inspired and tailored on the patient's characteristics, and correct judgement and experience play a pivotal role. A decisional algorithm has been proposed as an attempt to overcome the absence of specific guidelines and to guide the operative approach. This operative approach might be used also in non-cardiac procedure in which median sternotomy is required, such as in case of thoracic surgery.

Measurement of Adhesion of Sternal Wires to a Novel Bioactive Glass-Based Adhesive

Stainless steel wires are the standard method for sternal closure because of their strength and rigidity, the simplicity of the process, and the short healing time that results from their application. Despite this, problems still exist with sternal stability due to micromotion between the two halves of the dissected and wired sternum. Recently, a novel glass-based adhesive was developed which, in cadaveric trials and in conjunction with wiring, was shown to restrict this micromotion. However, in order to avoid complications during resternotomy, the adhesive should adhere only to the bone and not the sternal wire. In this study, sternal wires were embedded in 8 mm discs manufactured from the novel glass-based adhesive and the constructs were then incubated at 37 °C for one, seven, and 30 days. The discs were manufactured in two different thicknesses: 2 and 3 mm. Wire pull-out tests were then performed on the constructs at three different strain rates (1, 0.1, and 0.01 mm/min). No statistically significant difference in pull-out force was found regardless of incubation time, loading rate, or construct thickness. The pull-out forces recorded were consistent with static friction between the wire and adhesive, rather than the adhesion between them. Scanning electron micrographs provided further proof of this. These results indicate that the novel adhesive may be suitable for sternal fixation without complicating a potential resternotomy.

Novel adhesives for sternal fixation and stabilization: A biomechanical analysis

BACKGROUND

Cerclage wires remain the current standard of care following median sternotomy, despite significant complications including dehiscence and infection. This study uses a human cadaveric model to investigate the use of glass polyalkenoate cements formulated from two glasses, A (mole fraction: SiO₂:0.48, ZnO:0.36, CaO:0.12, SrO:0.04) and B (mole fraction: SiO₂:0.48, ZnO:0.355, CaO:0.06, SrO:0.08, P₂O₅:0.02, Ta₂O₅:0.005), to improve wired sternal fixation.

METHODS

Median sternotomies were performed on fifteen cadaveric sterna. Fixation was performed with either traditional wire cerclage or adhesive-enhanced wire cerclage; the adhesive based on either Glass A or Glass B. Cyclic tensile loading of 10 N to 100 N was applied. Every 30 cycles, the maximum load was increased by 100 N up to a maximum of 500 N. Two adhered sterna were tested beyond 500 N. Mid-sternal displacement was measured to assess fixation stability.

FINDINGS

Displacement for adhesive-enhanced sternal closures were significantly less (p < 0.05) than standard wire cerclage. There was no significant difference between adhesives. Up to 500 N, no adhesive-enhanced sternum experienced a pathological sternal displacement (>2 mm), while three out of five of traditional wire fixations did. Of the two adhered samples tested beyond 500 N, one showed pathological displacement at 800 N and the other at 1100 N. Failure of adhered sterna appeared to initiate within the trabecular bone rather than in the adhesive.

INTERPRETATION

The adhesives were capable of providing immediate bone stability, significantly reducing sternal displacement. In vivo investigations are warranted to determine the effect the adhesives have on bone remodelling.

Vibration transmittance measures sternotomy stability - a preliminary study in human cadavers

BACKGROUND

Stability is essential for the normal healing of a sternotomy. Mechanical vibration transmittance may provide a new means of early detection of diastasis in the sternotomy and thus enable the prevention of further complications. We sought to confirm that vibration transmittance detects sternal diastasis in human tissue.

METHODS

Ten adult human cadavers (8 males and 2 females) were used for sternal assessments with a device constructed in-house to measure the transmittance of a vibration stimulus across the median sternotomy at the second, third, and fourth costal cartilage. Intact bone was compared to two fixed bone junctions, namely a stable wire fixation and an unstable wire fixation with a 10 mm wide diastasis mimicking a widely rupturing sternotomy. A generalized Linear Mixed Model with the lme function was used to determine the ability of the vibration transmittance device to differentiate mechanical settings in the sternotomy.

RESULTS

The transmitted vibration power was statistically significantly different between the intact chest and stable sternotomy closure, stable and unstable closure, as well as intact and unstable closure (t-values and p-values respectively: t = 6.87, p < 0.001; t = 7.41, p < 0.001; t = 14.3, p < 0.001). The decrease of vibration transmittance from intact to stable at all tested costal levels was 78%, from stable to unstable 58%, and from intact to unstable 91%. The vibration transmittance power was not statistically significantly different between the three tested costal levels (level 3 vs. level 2; level 4 vs. level 2; level 4 vs. level 3; t-values and p-values respectively t = - 0.36, p = 0.723; t = 0.35, p = 0.728; t = 0.71, p = 0.484).

CONCLUSIONS

Vibration transmittance analysis differentiates the intact sternum, wire fixation with exact apposition, and wire fixation with a gap. The gap detection capability is not dependent on the tested costal level. The method may prove useful in the early detection of sternal instability and warrants further exploration.

Comparing Negative Pressure Wound Therapy with Instillation and Conventional Dressings for Sternal Wound Reconstructions

Background:

Muscle flap reconstruction has become a mainstay of therapy following treatment of sternal wound complications; however, success depends on removing wound exudate and infectious material from the wound before reconstruction and closure. Importantly, time to closure is a key factor affecting morbidity/mortality and cost-to-treat for this wound type.

Methods:

A retrospective analysis of 30 patients who were treated for sternal wound complications between June 2015 and October 2017 was performed. After surgical debridement, group 1 patients (n = 15) received negative pressure wound therapy (NPWT) with instillation and dwell time (NPWTi-d), instilling 1/8-strength Dakin’s solution with a 20-minute dwell time followed by 2 hours of NPWT (-125 mm Hg); group 2 patients (n = 15) were treated with wet-to-moist dressings soaked in 1/8-strength Dakin’s solution. After muscle flap reconstruction and closure with sutures, group 1 patients received closed incision negative pressure therapy, and group 2 patients received Benzoin and wound closure strips. Data collected included time to closure, therapy duration, number of debridements/dressing changes, drain duration, and complications.

Results:

There was a significantly shorter time to closure (P < 0.0001) for group 1 when compared with group 2. In addition, there were fewer therapy days (P = 0.0041), fewer debridements/dressing changes (P = 0.0011), and shorter drain duration (P = 0.0001) for group 1 when compared with group 2.

Conclusions:

We describe a novel regimen consisting of adjunctive NPWTi-d, along with debridement and systemic antibiotics, followed by closed incision negative pressure therapy after muscle flap reconstruction and closure, to help manage preexisting sternal wounds that had failed to close following a previous cardiac procedure.

Bilateral Internal Mammary Artery Bypass Grafting: Sternal Wound Infection in High-Risk Population. Should Sternal Infection Scare Us?

Background

Bilateral internal mammary arteries (BIMAs) remain underused in coronary artery bypass grafting (CABG), especially in elderly, diabetic, and obese patients. This study investigated incidence of sternal wound infection (SWI), sternal instability (SI), and reintervention for bleeding (RIB) in this high-risk population.

Methods

A single-center retrospective observational study was performed in "Grand Hôpital de Charleroi, Gilly, Belgium." A total of 319 patients undergoing CABG from December 2011 to December 2015 were included. Three main outcome measures (SWI, SI, and RIB) were investigated in obese vs nonobese, diabetic vs nondiabetic, and elderly vs younger patients.

Results

In all, 14 SWI, 11 SI, and 6 RIB were discounted. Death rate was as follows: SWI: 2/14 vs 17/305 (P = .178), SI: 2/11 vs 17/308 (P = .081), and RIB: 2/6 vs 17/313 (P = .004). In obese (n = 113) vs nonobese (n = 206) patients, there was no difference for SWI (P = .263), SI (P = .565), and RIB (P = .332). In diabetic (n = 118) vs nondiabetic (n = 201) patients, there was no difference for SWI (P = .642), SI (P = .497), and RIB (P = .298). In elderly (n = 62) vs younger (n = 257) patients, there was no difference for SWI (P = .619), SI (P = .915), and RIB (P = .385).

Conclusions

Obesity, age, and diabetes treated by insulin (or not) do not seem to be risk factors for developing SWI, SI, or RIB in patients receiving a CABG using BIMA. Nevertheless, mortality was higher in RIB group.

Motion at the Sternal Edges During Upper Limb and Trunk Tasks In-Vivo as Measured by Real-Time Ultrasound Following Cardiac Surgery: A Three-Month Prospective, Observational Study

BACKGROUND

Despite a paucity of evidence, patients following cardiac surgery via median sternotomy are routinely prescribed sternal precautions that restrict upper limb and trunk movements, with the rationale of reducing postoperative sternal complications such as sternal wound dehiscence, instability, infection and/or pain. The primary aim of this study was to measure motion at the sternal edges during dynamic upper limb and trunk tasks to better inform future sternal precautions and optimise postoperative recovery. Motion at the sternal edges was measured using ultrasound, which has been demonstrated to be a clinically valid and reliable measure in patients following cardiac surgery.

METHODS

Seventy-five (75) patients following cardiac surgery via median sternotomy with conventional stainless steel wire closure were recruited. Motion at the sternal edges in the lateral (coronal plane) and anterior-posterior (sagittal plane) directions was measured at the level of the fourth intercostal space (mid-sternum) using ultrasound. Ultrasound measures were taken at rest and during five dynamic upper limb and trunk tasks (deep inspiration, cough, unilateral and bilateral upper limb elevation and sit to stand), over the first 3 postoperative months (3 to 7 days, 6 weeks and 3 months postoperatively). Sternal pain, functional status and sternal healing were also observed over the same postoperative period.

RESULTS

The magnitude of overlap of the sternal edges in the lateral direction, and separation of the sternal edges in the anterior-posterior direction, both significantly decreased by 0.01cm, over the first 3 postoperative months (p<0.01). Coughing, however, produced a significant increase in separation of the sternal edges in the lateral direction (0.01-0.02cm) and pain (12-63%), compared to rest and all other tasks, at each postoperative time point (p<0.01). Additionally, there was a significant decrease in sternal pain (81%) and increase in postoperative function (79%) over the same postoperative period (p<0.01). At 3 months postoperatively, five (7%) participants demonstrated radiological sternal union and one (1%) participant was diagnosed with clinical sternal instability.

CONCLUSIONS

A small magnitude of multi-planar motion at the sternal edges, at the mid-sternum, was demonstrated during dynamic upper limb and trunk tasks in a cohort of cardiac surgery patients post-sternotomy, over the first 3 postoperative months. Future research investigating motion at different levels of the sternum, with varying methods of sternal closure, and over a longer postoperative period is warranted to better inform sternal precautions and optimise postoperative recovery.

Standard restrictive sternal precautions and modified sternal precautions had similar effects in people after cardiac surgery via median sternotomy ('SMART' Trial): a randomised trial

QUESTION

In people who have undergone cardiac surgery via median sternotomy, does modifying usual sternal precautions to make them less restrictive improve physical function, pain, kinesiophobia and health-related quality of life?

DESIGN

Two-centre, randomised, controlled trial with concealed allocation, blinded assessors and intention-to-treat analysis.

PARTICIPANTS

Seventy-two adults who had undergone cardiac surgery via a median sternotomy were included.

INTERVENTION

Participants were randomly allocated to one of two groups at 4 (SD 1) days after surgery. The control group received the usual advice to restrict their upper limb use for 4 to 6 weeks (ie, restrictive sternal precautions). The experimental group received advice to use pain and discomfort as the safe limits for their upper limb use during daily activities (ie, less restrictive precautions) for the same period. Both groups received postoperative individualised education in hospital and via weekly telephone calls for 6 weeks.

OUTCOME MEASURES

The primary outcome was physical function assessed by the Short Physical Performance Battery. Secondary outcomes included upper limb function, pain, kinesophobia, and health-related quality of life. Outcomes were measured before hospital discharge and at 4 and 12 weeks postoperatively. Adherence to sternal precautions was recorded.

RESULTS

There were no statistically significant differences in physical function between the groups at 4 weeks (MD 1.0, 95% CI -0.2 to 2.3) and 12 weeks (MD 0.4, 95% CI -0.9 to 1.6) postoperatively. There were no statistically significant between-group differences in secondary outcomes.

CONCLUSION

Modified (ie, less restrictive) sternal precautions for people following cardiac surgery had similar effects on physical recovery, pain and health-related quality of life as usual restrictive sternal precautions. Similar outcomes can be anticipated regardless of whether people following cardiac surgery are managed with traditional or modified sternal precautions.

TRIAL REGISTRATION

Australian and New Zealand Clinical Trials Registry ANZCTRN12615000968572. [Katijjahbe MA, Granger CL, Denehy L, Royse A, Royse C, Bates R, Logie S, Nur Ayub MA, Clarke S, El-Ansary D (2018) Standard restrictive sternal precautions and modified sternal precautions had similar effects in people after cardiac surgery via median sternotomy ('SMART' Trial): a randomised trial. Journal of Physiotherapy 64: 97-106].

Omentum flap as a salvage procedure in deep sternal wound infection

INTRODUCTION

Deep sternal wound infections (DSWIs) are rare but devastating complication after median sternotomy following cardiac surgery. Especially in the presence of artificial material or inadequate preliminary muscle flaps, the pedicled omentum flap is due to its immunological properties, the predetermined flap in salvage procedures.

METHODS

We treated 14 patients suffering a mediastinitis and open thorax using a pedicled omentoplasty as a salvage procedure because of persisting DSWIs. Omentoplasty was performed in combination with a split skin graft and the wound was closed by a vacuum-assisted therapy for 7 days. The patients' sex and comorbid risk factors supporting DSWIs as well as the postoperative complications were recorded.

RESULTS

Retrospective analysis of 14 patients (10 males and four females) after a follow-up time of 24 months was performed. The average age was 75 years (range: 67-83). Heart surgery took place electively in eight cases, in three cases urgently and three for emergency reasons. The preoperative Euro Score was 16 (range 3.51-42.58). We had no flap loss in any patients. The skin graft showed a full take in all patients. Two patients needed revision of an abdominal wound dehiscence after laparotomy and one patient developed hernia in the late outcome.

DISCUSSION

The greater omentum flap has, over many years, become an ideal partner in the coverage and treatment of DSWIs. Especially due to its immunologic capacity and amorphous structure, it has the ability to fill up cavities and cover infected artificial material so residual infections can be controlled.

Adhesive-Enhanced Sternal Closure: Feasibility and Safety of Late Sternal Reentry

This clinical case report describes sternal reentry performed years after adhesive-enhanced sternal closure using Kryptonite bone cement. This report provides novel data on the late effects of this innovation. We observed that sternal reentry is feasible and safe. The adhesive did not weaken from biodegradation over a period of several years. There was no evidence of adherence to adjacent soft tissues or other nonbony deep mediastinal structures. Surgeons who receive patients who require redoing cardiac surgery after adhesive-enhanced closure with Kryptonite can be reassured that sternal reentry is safe and feasible.

Respiratory motion compensation for the robot-guided laser osteotome

PURPOSE

The use of a robot-guided laser osteotome for median sternotomy is impeded by prohibiting cutting inaccuracies due to respiration-induced motions of the thorax. With this paper, we advance today's methodologies in sternotomy procedures by introducing the concept of novel 3D functional cuts and a respiratory motion compensation algorithm for the computer-assisted and robot-guided laser osteotome, CARLO^®.

METHODS

We present a trajectory planning algorithm for performing 3D functional cuts at a constant cutting velocity. In addition, we propose the use of Gaussian process (GP) prediction in order to anticipate the sternum's pose providing enough time for the CARLO^® device to adjust the position of the laser source.

RESULTS

We analysed the performance of the proposed algorithms on a computer-based simulation framework of the CARLO^® device. The median position error of the laser focal point has shown to be reduced from 0.22 mm without GP prediction to 0.19 mm with GP prediction.

CONCLUSION

The encouraging simulation results support the proposed respiratory motion compensation algorithm for robot-guided laser osteotomy on the thorax. Successful compensation of the respiration-induced motion of the thorax opens doors for robot-guided laser sternotomy and the related novel cutting patterns. These functional cuts hold great potential to significantly improve postoperative sternal stability and therefore reduce pain and recovery time for the patient. By enabling functional cuts, we approach an important threshold moment in the history of osteotomy, creating innovative opportunities which reach far beyond the classic linear cutting patterns.

Risk Factors for Sternal Wound Infection After Open Heart Operations Vary According to Type of Operation

BACKGROUND

This study evaluated whether risk factors for sternal wound infections vary with the type of surgical procedure in cardiac operations.

METHODS

This was a university hospital surveillance study of 3,249 consecutive patients (28% women) from 2006 to 2010 (median age, 69 years [interquartile range, 60 to 76]; median additive European System for Cardiac Operative Risk Evaluation score, 5 [interquartile range, 3 to 8]) after (1) isolated coronary artery bypass grafting (CABG), (2) isolated valve repair or replacement, or (3) combined valve procedures and CABG. All other operations were excluded. Univariate and multivariate binary logistic regression were conducted to identify independent predictors for development of sternal wound infections.

RESULTS

We detected 122 sternal wound infections (3.8%) in 3,249 patients: 74 of 1,857 patients (4.0%) after CABG, 19 of 799 (2.4%) after valve operations, and 29 of 593 (4.9%) after combined procedures. In CABG patients, bilateral internal thoracic artery harvest, procedural duration exceeding 300 minutes, diabetes, obesity, chronic obstructive pulmonary disease, and female sex (model 1) were independent predictors for sternal wound infection. A second model (model 2), using the European System for Cardiac Operative Risk Evaluation, revealed bilateral internal thoracic artery harvest, diabetes, obesity, and the second and third quartiles of the European System for Cardiac Operative Risk Evaluation were independent predictors. In valve patients, model 1 showed only revision for bleeding as an independent predictor for sternal infection, and model 2 yielded both revision for bleeding and diabetes. For combined valve and CABG operations, both regression models demonstrated revision for bleeding and duration of operation exceeding 300 minutes were independent predictors for sternal infection.

CONCLUSIONS

Risk factors for sternal wound infections after cardiac operations vary with the type of surgical procedure. In patients undergoing valve operations or combined operations, procedure-related risk factors (revision for bleeding, duration of operation) independently predict infection. In patients undergoing CABG, not only procedure-related risk factors but also bilateral internal thoracic artery harvest and patient characteristics (diabetes, chronic obstructive pulmonary disease, obesity, female sex) are predictive of sternal wound infection. Preventive interventions may be justified according to the type of operation.

Reconstruction of massive post-sternotomy defects with allogeneic bone graft: four-year results and experience using the method

OBJECTIVES

Deep sternal wound infection poses a serious problem in cardiac surgery, with an up to 40% risk of mortality. Massive loss of sternum bone tissue and adjacent ribs results in major chest wall instability causing respiratory insufficiency and defects of soft tissue healing. Proposals for managing the situation have been published but the complexity of the issue precludes unequivocal resolution. Capitalizing on orthopaedic experience, we used allogeneic bone graft of sternum as a viable option.

METHODS

We performed the transplantation of allogeneic bone graft in 10 patients. In 9 cases, an allograft of sternum was used and in 1 case an allograft of calva bone. After the primary cardiac surgery, a massive post-sternotomy defect of the chest wall had developed in all 10 patients. Vacuum wound drainage was applied in the treatment of all patients. To stabilize the transverse, titanium plates were used. Bone allograft was prepared by the official Tissue Centre. Crushed allogeneic spongy bone was applied to reinforce the line of contact of the graft and the edges of residual skeleton. In 9 cases, the soft tissue was closed by direct suture of mobilized pectoral flaps. In 1 case, V-Y transposition of pectoral flap was performed.

RESULTS

In 6 cases, healing of the reconstructed chest wall occurred without further complications. In 3 cases, additional re-suture of the soft tissues and skin in the lower pole of the wound was necessary. Excellent chest wall stability along with the adjustment of respiratory insufficiency and good cosmetic effect was achieved in all cases. In 1 case, severe concomitant complications and no healing of the wound resulted in death within 6 months after the reconstruction. Median follow-up of all patients in the series was 14.1 months (1-36 months). In 4 patients, scintigraphy of the chest wall was performed.

CONCLUSIONS

Our existing results show that allogeneic bone graft transplantation is a promising and easily applied method in the management of serious tissue loss in sternal dehiscence with favourable functional and cosmetic effects. The relatively small number of patients with such severe healing complications of sternotomy however puts critical limits to a more detailed comparison with other practices and evaluation of long-term results.