Mechanisms governing the effects of vacuum-assisted closure in cardiac surgery

Vacuum-assisted closure therapy for the management of deep sternal wound complications: A systematic review and meta-analysis

BACKGROUND

Vacuum-assisted closure (VAC) therapy has become a popular treatment option for wound healing. The aim of this meta-analysis was to assess the use of VAC therapy as a bridge before the definitive treatment for the management of deep sternal wound complications.

METHODS

A systematic literature review and meta-analysis were performed in PubMed and Embase. Outcomes of interest included mortality, treatment failure, length of hospital stay (LOS), length of intensive care unit (ICU) stay and cost of treatment.

RESULTS

Twenty-two studies involving 1980 patients were included in the quantitative synthesis of this meta-analysis. Patients treated with VAC had significantly lower overall mortality [1738 patients; Risk ratio [RR] = 0.36 (95% confidence interval [CI]: 0.25, 0.51)], treatment failure [1210 patients; RR = 0.26 (95% CI: 0.19, 0.37)], LOS [498 patients; (standard mean difference = -0.44 (95% CI: -0.81, -0.07)] and ICU stay [309 patients; (standard mean difference = -0.34 (95% CI: -0.67, -0.01)] compared to that of non-VAC patients. VAC therapy was associated with reduced cost of treatment per patient compared with that of non-VAC therapies (reductions of 3600 USD, 6000 USD and 8983 USD in the reported studies).

CONCLUSIONS

VAC therapy as an adjunct in the definitive treatment of patients with deep sternal wound complications was associated with lower mortality, treatment failure, LOS, ICU stay and cost of treatment when compared with a non-VAC approach. Randomised controlled trials would be essential to confirm these findings.

Vacuum-assisted closure therapy combined with bi-pectoral muscle flap for the treatment of deep sternal wound infections

Deep sternal wound infection (DSWI) is a fatal complication after median sternotomy. This study was to assess the effect of vacuum-assisted closure (VAC) combined with bi-pectoral muscle advancement flap therapy on rehabilitation for the treatment of DSWI. Fifty-two patients with DSWI underwent treatment of VAC and bi-pectoral muscle flap. These patients were followed-up 12 months postoperation. The patient characteristics, duration of VAC therapy, the mean hospital stay, and postoperative complications were retrospectively analysed. All patients underwent 1 to 3 VAC treatment sessions before closure. Fifty-one of 52 DSWI patients were cured to discharge; the mean hospital stay was 26.5 days. The drainage tube continued to drain a large amount of bloody fluid in three patients after the wound was closed. Respiratory failure occurred in one patient with severe mediastinal and pulmonary infections and died eventually in hospital. One patient died of acute cerebral haemorrhage during the12-month follow-up. VAC therapy combined with bi-pectoral muscle flap is a simple and effective treatment for DSWIs with short hospital stays and few complications. However, this is a retrospective case series presentation with no comparison group; further large-scale controlled studies are needed.

EWMA Document: Negative Pressure Wound Therapy

1. Introduction Since its introduction in clinical practice in the early 1990's negative pressure wounds therapy (NPWT) has become widely used in the management of complex wounds in both inpatient and outpatient care.¹ NPWT has been described as a effective treatment for wounds of many different aetiologies^2,3 and suggested as a gold standard for treatment of wounds such as open abdominal wounds,^4-6 dehisced sternal wounds following cardiac surgery^7,8 and as a valuable agent in complex non-healing wounds.^9,10 Increasingly, NPWT is being applied in the primary and home-care setting, where it is described as having the potential to improve the efficacy of wound management and help reduce the reliance on hospital-based care.¹¹ While the potential of NPWT is promising and the clinical use of the treatment is widespread, highlevel evidence of its effectiveness and economic benefits remain sparse.^12-14 The ongoing controversy regarding high-level evidence in wound care in general is well known. There is a consensus that clinical practice should be evidence-based, which can be difficult to achieve due to confusion about the value of the various approaches to wound management; however, we have to rely on the best available evidence. The need to review wound strategies and treatments in order to reduce the burden of care in an efficient way is urgent. If patients at risk of delayed wound healing are identified earlier and aggressive interventions are taken before the wound deteriorates and complications occur, both patient morbidity and health-care costs can be significantly reduced. There is further a fundamental confusion over the best way to evaluate the effectiveness of interventions in this complex patient population. This is illustrated by reviews of the value of various treatment strategies for non-healing wounds, which have highlighted methodological inconsistencies in primary research. This situation is confounded by differences in the advice given by regulatory and reimbursement bodies in various countries regarding both study design and the ways in which results are interpreted. In response to this confusion, the European Wound Management Association (EWMA) has been publishing a number of interdisciplinary documents^15-19 with the intention of highlighting: The nature and extent of the problem for wound management: from the clinical perspective as well as that of care givers and the patients Evidence-based practice as an integration of clinical expertise with the best available clinical evidence from systematic research The nature and extent of the problem for wound management: from the policy maker and healthcare system perspectives The controversy regarding the value of various approaches to wound management and care is illustrated by the case of NPWT, synonymous with topical negative pressure or vacuum therapy and cited as branded VAC (vacuum-assisted closure) therapy. This is a mode of therapy used to encourage wound healing. It is used as a primary treatment of chronic wounds, in complex acute wounds and as an adjunct for temporary closure and wound bed preparation preceding surgical procedures such as skin grafts and flap surgery. Aim An increasing number of papers on the effect of NPWT are being published. However, due to the low evidence level the treatment remains controversial from the policy maker and health-care system's points of view-particularly with regard to evidence-based medicine. In response EWMA has established an interdisciplinary working group to describe the present knowledge with regard to NPWT and provide overview of its implications for organisation of care, documentation, communication, patient safety, and health economic aspects. These goals will be achieved by the following: Present the rational and scientific support for each delivered statement Uncover controversies and issues related to the use of NPWT in wound management Implications of implementing NPWT as a treatment strategy in the health-care system Provide information and offer perspectives of NPWT from the viewpoints of health-care staff, policy makers, politicians, industry, patients and hospital administrators who are indirectly or directly involved in wound management.

Effective Combination of Different Surgical Strategies for Deep Sternal Wound Infection and Mediastinitis

Purpose: Timing and ideal reconstructive approach in deep sternal wound infection (DSWI) and mediastinitis still remain controversially debated. We present our own combined surgical strategy of bilateral pectoralis major muscle flap (BPMMF) or omental flap (OF) transposition.

Methods: Between July 2010 and July 2016, poststernotomy patients with DSWI and mediastinitis underwent a secondary wound closure with modified BPMMF (Group A, center for disease control class (CDC)-II, n = 21; Group B, CDC-III, n = 20) or with OF (Group C, CDC-III, n = 19) following vacuum-assisted closure (VAC).

Results: Significant risk factors for mediastinitis (CDC-III) were chronic obstructive pulmonary disease (COPD; p = 0.001), peripheral arterial disease (PAD; p = 0.012), cardiopulmonary bypass (CPB) time (p = 0.027), total operation time (p = 0.039), total intensive care unit (ICU) stay (p = 0.011), and blood transfusion (p = 0.049). Mean antibiotic therapy (18.4 ± 8.8[B] vs. 36.2 ± 24.4[C] days, p = 0.026) and length of hospitalization (25.2 ± 12.1[B] vs 53.8 ± 18.5 days[C], p = 0.053) were significantly longer in group C. In-hospital death was 3/19 (15.8%) in group C versus 0 in group B (p = 0.026). Frequency of recurrent mediastinitis was equal (p = 0.92); however, complications occurred more often in group C (31.6% vs. 0%, p = 0.031). The mean follow-up time was 111 ± 62 days.

Conclusion: In younger (<70 years) patients without sternal bone necrosis, the BPMMF is superior to the OF technique with relatively low recurrence and mortality risks.

[Impact of vacuum-assisted closure management in deep neck abscesses]

BACKGROUND

The presence of deep neck abscesses is potentially serious; they can lead to death in a short period of time. The vacuum-assisted closure (V.A.C.) therapy has been used in many areas of surgery for complex wound healing. This treatment modality has recently been considered in the field of head and neck surgery.

OBJECTIVE

Evaluate the efficacy of healing therapy using V.A.C. therapy in deep neck abscesses.

MATERIAL AND METHODS

Open-label trial. Patients with deep neck abscesses were included using V.A.C. therapy versus conventional therapy. Cultures were taken before and during surgery, and prior to primary wound closure. The percentages of healing, viable tissue, wound healing time, and hospital stay were evaluated.

RESULTS

A total of 18 patients were included. Affected neck spaces: submaxilar 29%, parapharyngeal 22%, submental 21% and masticatory 13%. The final postsurgical culture was negative in 78%. Viable tissue of the wound for the V.A.C. group was 42%, and for the control group was 36% (p=0.025). Healing time was 22±6 days and 38±15.5, respectively (p = 0.01). The mean number of hospital stay was 12 days for both groups.

CONCLUSIONS

Therapy with V.A.C. is useful in the treatment of deep neck abscesses; it decreased healing time as a result of more viable tissue allowing suture closure of the wound in a shorter period.

Assessment of vacuum-assisted closure therapy on the wound healing process in cardiac surgery

Postoperative deep sternal wound infection (DSWI) is a serious complication in cardiac surgery (1-5% of patients) with high mortality and morbidity rates. Vacuum-assisted closure (VAC) therapy has shown promising results in terms of wound healing process, postoperative hospital length of stay and lower in-hospital costs. The aim of our retrospective study is to report the outcome of patients with DSWI treated with VAC therapy and to assess the effect of contributory risk factors. Data of 52 patients who have been treated with VAC therapy in a single institution (study period: September 2003-March 2012) were collected electronically through PAtient Tracking System PATS and statistically analysed using SPSS version 20. Of the 52 patients (35 M: 17 F), 88·5% (n = 46) were solely treated with VAC therapy and 11·5% (n = 6) had additional plastic surgical intervention. Follow-up was complete (mean 33·8 months) with an overall mortality rate of 26·9% (n = 14) of whom 50% (n = 7) died in hospital. No death was related to VAC complications. Patient outcomes were affected by pre-operative, intra-operative and postoperative risk factors. Logistic EUROscore, postoperative hospital length of stay, advanced age, chronic obstructive pulmonary disease (COPD) and long-term corticosteroid treatment appear to be significant contributing factors in the long-term survival of patients treated with VAC therapy.

The HeartShield device reduces the risk for right ventricular damage in patients with deep sternal wound infection

OBJECTIVE

Right ventricular rupture, resulting in serious bleeding, is a life-threatening complication associated with negative-pressure wound therapy (NPWT) in cardiac surgery. The use of a rigid barrier between the heart and the sharp sternal edges has been successfully tested on pigs. In the present article, we demonstrate increased safety in NPWT through the use of the HeartShield device.

METHODS

Six patients were treated with a specially designed device in combination with NPWT. The device consists of a horizontally placed disk covered in foam. The back of the T-shaped device sticks up between the sternal edges and up above skin level. This part of the device is also covered in foam. Drainage is performed through two holes at the top of the device. The device and foam are changed every second to third day, and -120 mm Hg of continuous therapy is used. Six patients were treated with traditional NPWT, serving as control group.

RESULTS

No signs of calluslike formation were seen on the right ventricle in the group treated with the HeartShield device. In the conventional NPWT control group, all six patients had calluslike formation (>1 × 2 cm2) on the anterior part of the right ventricle. All patients in the HeartShield group had grade 1 epicardial petechial bleeding (<0.5 cm2) on the right ventricle. In the control group, one patient had grade 1 (<0.5 cm2), three patients had grade 2 (0.5-2.0 cm2), and two patients had grade 3 (>2.0 cm2) epicardial petechial bleeding on the right ventricle. No major bleeding or mortality was observed in either group during the course of the study.

CONCLUSIONS

The use of the HeartShield device significantly minimizes the contact between the right ventricle and the sternal edges, thereby decreasing the risk for life-threatening complications due to bleeding.

Titanium plate fixation for sternal dehiscence in major cardiac surgery

Background

Sternal dehiscence is one of the most troublesome complications following cardiac surgery. Treatment failure and consequent lethal outcomes are very common. The aim of this study was to evaluate titanium plate fixation as a treatment for sternal dehiscence following major cardiac surgery.

Materials and Methods

Between 2010 and 2012, 17 patients underwent sternal reconstruction using horizontal titanium plating for the treatment of post-cardiac-surgery sternal dehiscence. The plates were cut and shaped, and then were fixed to corresponding costal segments using 2-3 titanium screws per each side.

Results

The median age of our patients was 66 years (range, 50 to 78 years) and 9 were female. Indications for sternal reconstruction included aseptic sternal dehiscence in 3 patients and osteomyelitis in 14 patients including 6 patients who were diagnosed with mediastinitis. During the operation, sternal resection and autologous flap interposition were combined in 11 patients. One patient died due to sepsis. Two patients required additional soft tissue wound revisions. Another patient presented with a tuberculous wound infection which was resolved using anti-tuberculosis medications. The postoperative course was uncomplicated in the other 13 patients.

Conclusion

Titanium plate fixation that combines appropriate debridement and flap interposition is very effective for the treatment of sternal dehiscence following major cardiac surgery.

New chest tube management maintained with negative pressure therapy

Management of a chest tube, especially when lasting for a long period, becomes difficult. The orifice of thoracostomy where a tube is inserted is maintained sterile usually with water-tight sutures. The longer and tighter the sutures are placed, the more severely skin becomes sore by pressure. Recently not only pressure sores but also other various open wounds were successfully treated by negative pressure therapy. This study presents two cases of intrathoracic abscess which were successfully treated by chest tube maintained with negative pressure therapy. One case was a bed-ridden cerebral palsy patient with empyema thoracis and the other was a premature baby with lung abscess. Both needed a chest tube longer than a month. Negative pressure was applied not only in the abscess cavity but also in the wound of tube insertion, thus simultaneously draining the abscess and accelerating the wound healing of the tube insertion. It was gradually elevated from 20 to 50 H2O (14.7 to 36.7 mmHg), which is below the level of the physiologic forced inspiration, with a 10 cm H2O (7.4 mmHg) increase every other day. Both abscesses disappeared without a complication.

C-reactive protein and leucocyte counts drop faster using the HeartShield® device in patients with DSWI

Right ventricular heart rupture is a devastating complication associated with negative pressure wound therapy (NPWT) in cardiac surgery. The use of a rigid barrier disc (HeartShield™) has been suggested to offer protection against this lethal complication by preventing the heart from being drawn up by the negative pressure and damaged by the sharp sternum bone edges. Seven patients treated with conventional NPWT and seven patients treated with NPWT with a protective barrier disc (HeartShield) were compared with regard to bacterial clearance and infection parameters including C-reactive protein levels and leucocyte counts. C-reactive protein levels and leucocyte counts dropped faster and bacterial clearance occurred earlier in the HeartShield® group compared with the conventional NPWT group. Negative biopsy cultures were shown after 3·1 ± 0·4 NPWT dressing changes in the HeartShield group, and after 5·4 ± 0·6 NPWT dressing changes in the conventional NPWT group (P < 0·001). All patients were followed up with clinical check-up after 3 months. None of the patients in the HeartShield group had any signs of reinfection such as deep sternal wound infection (DSWI) or sternal fistulas, whereas in the conventional NPWT group, two patients had signs of sternal fistulas that demanded hospitalisation. HeartShield hinders the right ventricle to come into contact with the sharp sternal edges during NPWT and thereby protects from heart damage. This study shows that using HeartShield is beneficial in treating patients with DSWI. Improved wound healing by HeartShield may be a result of the efficient drainage of wound effluents from the thoracic cavity.

Negative pressure wound therapy for the treatment of sternal wound infections after cardiac surgery

We retrospectively collected and analysed data from patients with sternal wound infections between 1995 and 2001, which were treated with different wound management strategies, and compared them with our patients from 2002 to 2011, who were treated with the sternal negative pressure wound therapy (NPWT). From 1995 to 2001, a total of 198 patients (group A) with a mean age of 65 ± 10 years developed sternal wound infection (67% deep) after cardiac surgery. Wound management consisted of surgical debridement and immediate sternal closure or open packing. From 2002 to 2011, a total of 326 patients (group B) (71% deep) were managed with NPWT at the time of surgical debridement. Total mortality was 10% in group A and 3·6% in group B. Recurrence rates were 34 and 8·5%, respectively, for the groups A and B. The meantime of NPWT was 11 days. In group B patients, 75% proceeded to sternal closure. With the introduction of NPWT, the treatment of sternal wound infections could be substantially improved. Particularly, the high recurrence rates could be minimised; furthermore, the goal to salvage the sternal bone is facilitated.

Topical negative pressure for the treatment of neonatal post-sternotomy wound dehiscence

The use of topical negative pressure (TNP) dressings for sternal wound dehiscence or mediastinitis in the neonatal population is rare. The majority of case reports have focused on wound healing as an endpoint and have not discussed the physiological advantage that TNP dressings may impart with regard to sternal stabilisation, improved respiratory function and early weaning from mechanical ventilation. We present a case of the use of TNP in neonatal post-sternotomy wound dehiscence and mediastinitis, from a UK perspective, with an emphasis on wound healing and physiological optimisation. As well as an improvement in sternal wound healing due to the local effects of the TNP system, serial arterial blood gas analysis revealed a significant improvement in systemic physiological parameters, including a reduction in pCO(2) in the period (days 20-31) after application of TNP (p<0.0001) compared to the period before where simple occlusive dressings were applied. Hydrogen ion concentration also significantly reduced in this period (p=0.0058). The use of the TNP system in association with systemic antibiotics successfully treated the mediastinitis. A sealed, controlled wound environment also allowed ease of nursing and an expedited return to care by the parents. We would recommend the consideration of TNP dressings in similar cases of neonatal and paediatric sternal wound dehiscence. Not only do we observe the local effects of improved wound healing, the systemic effects of improved lung function are also valuable in the early management of such complex cases.

A rigid disc for protection of exposed blood vessels during negative pressure wound therapy

BACKGROUND

There are increasing reports of serious complications and deaths associated with negative pressure wound therapy (NPWT). Bleeding may occur when NPWT is applied to a wound with exposed blood vessels. Inserting a rigid disc in the wound may protect these structures. The authors examined the effects of rigid discs on wound bed tissue pressure and blood flow through a large blood vessel in the wound bed during NPWT.

METHODS

Wounds were created over the femoral artery in the groin of 8 pigs. Rigid discs were inserted. Wound bed pressures and arterial blood flow were measured during NPWT.

RESULTS

Pressure transduction to the wound bed was similar for control wounds and wounds with discs. Blood flow through the femoral artery decreased in control wounds. When a disc was inserted, the blood flow was restored.

CONCLUSIONS

NPWT causes hypoperfusion in the wound bed tissue, presumably as a result of mechanical deformation. The insertion of a rigid barrier alleviates this effect and restores blood flow.

Effects on drainage of the mediastinum and pleura during negative pressure wound therapy when using a rigid barrier to prevent heart rupture

Right ventricular heart rupture is a devastating complication associated with negative pressure wound therapy (NPWT) following cardiac surgery. The use of a rigid disc has been suggested to offer protection against this lethal complication by preventing the heart from being drawn up towards, and damaged by, the sharp sternum edges. The aim of the present study was to compare the wound fluid evacuation from the pericardium and the left pleura when using NPWT with such a disc between the sternal edges and the heart, and when using conventional NPWT. Six pigs underwent median sternotomy followed by NPWT at -120 mmHg, using foam, with or without a rigid plastic disc between the heart and the sternal edges. A 250 ml saline was infused into the pericardium, and the time required for fluid evacuation was measured. A 500 ml saline was infused into the left pleura and the time for fluid evacuation measured. The pericardium was effectively drained of 250 ml fluid in both cases [conventional NPWT: 24 ± 0·7 seconds, NPWT with the disc: 25 ± 1·1 seconds (n.s.)]. The left pleura was effectively drained when using NPWT with the disc, but was not drained at all when using conventional NPWT. The left pleura could be effectively drained of 500 ml fluid when a rigid perforated plastic disc was inserted between the sternal edges and the heart during NPWT. Significantly less drainage of the left pleura was possible when using conventional NPWT without the disc. The pericardium was equally good drained using NPWT with or without the disc.

Haemodynamic effects of negative pressure wound therapy when using a rigid barrier to prevent heart rupture

Right ventricular heart rupture is a devastating complication associated with negative pressure wound therapy (NPWT) in cardiac surgery. The use of a rigid barrier has been suggested to offer protection against this lethal complication by preventing the heart from being drawn up and damaged by the sharp sternum bone edges. The aim of this study was to investigate the haemodynamic effects of placing a rigid barrier over the heart to protect it from rupture during NPWT. Eight pigs underwent median sternotomy followed by NPWT at --70 and --120 mmHg, using foam, with or without a rigid plastic disc between the heart and the sternal edges. The heart frequency, cardiac output, mean systemic arterial pressure, mean pulmonary artery pressure, central venous pressure and left atrial pressure were recorded. Cardiac output was not affected by NPWT, regardless of whether a rigid barrier was used. Heart frequency decreased during NPWT without a disc, and showed a tendency towards a decrease when using a rigid disc. The blood pressure decreased during NPWT without a disc, and showed only a tendency towards a decrease when a disc was inserted between the heart and the sternum. In conclusion, the results of this haemodynamic study show that a rigid disc can safely be placed over the heart during NPWT, to prevent heart rupture. The haemodynamic effects of NPWT in sternotomy wounds are slightly reduced by the presence of the rigid disc.

The influence on wound contraction and fluid evacuation of a rigid disc inserted to protect exposed organs during negative pressure wound therapy

The use of a rigid disc as a barrier between the wound bed and the wound filler during negative pressure wound therapy (NPWT) has been suggested to prevent damage to exposed organs. However, it is important to determine that the effects of NPWT, such as wound contraction and fluid removal, are maintained during treatment despite the use of a barrier. This study was performed to examine the effect of NPWT on wound contraction and fluid evacuation in the presence of a rigid disc. Peripheral wounds were created on the backs of eight pigs. The wounds were filled with foam, and rigid discs of different designs were inserted between the wound bed and the foam. Wound contraction and fluid evacuation were measured after application of continuous NPWT at -80 mmHg. Wound contraction was similar in the presence and the absence of a rigid disc (84 ± 4% and 83 ± 3%, respectively, compared with baseline). Furthermore, the rigid disc did not affect wound fluid removal compared with ordinary NPWT (e.g. after 120 seconds, 71 ± 4 ml was removed in the presence and 73 ± 3 ml was removed in the absence of a disc). This study shows that a rigid barrier may be placed under the wound filler to protect exposed structures during NPWT without affecting wound contraction and fluid removal, which are two crucial features of NPWT.

The influence of different sizes and types of wound fillers on wound contraction and tissue pressure during negative pressure wound therapy

Negative pressure wound therapy (NPWT) contracts the wound and alters the pressure in the tissue of the wound edge, which accelerates wound healing. The aim of this study was to examine the effect of the type (foam or gauze) and size (small or large) of wound filler for NPWT on wound contraction and tissue pressure. Negative pressures between --20 and --160 mmHg were applied to a peripheral porcine wound (n = 8). The pressure in the wound edge tissue was measured at distances of 0·1, 0·5, 1·0 and 2·0 cm from the wound edge and the wound diameter was determined. At 0·1 cm from the wound edge, the tissue pressure decreased when NPWT was applied, whereas at 0·5 cm it increased. Tissue pressure was not affected at 1·0 or 2·0 cm from the wound edge. The tissue pressure, at 0·5 cm from the wound edge, was greater when using a small foam than when using than a large foam. Wound contraction was greater when using a small foam than when using a large foam during NPWT. Gauze resulted in an intermediate wound contraction that was not affected by the size of the gauze filler. The use of a small foam to fill the wound causes considerable wound contraction and may thus be used when maximal mechanical stress and granulation tissue formation are desirable. Gauze or large amounts of foam result in less wound contraction which may be beneficial, for example when NPWT causes pain to the patient.

Deep sternal wound infection after open heart surgery: current treatment insights. A retrospective study of 36 cases

The aim of this study was to retrospectively evaluate the results of reconstructing infected post-sternotomy wounds, with either sternal plating and/or pectoralis major flap transposition or pedicled omentoplasty after previous vacuum-assisted closure (VAC) therapy. Between January 2005 and December 2010, 36 patients, suffering from deep sternal wound infection (DSWI) after coronary artery bypass grafting procedure, received (plastic) reconstructive surgery. All patients, treated in the Maastricht University Medical Centre (Departments of Plastic Surgery and Cardiothoracic Surgery), were selected for this study. For 22 patients, sternal refixation and reconstruction were obtained by sternal internal plate fixation combined with bilateral pectoralis major advancement flap. In 11 patients, a pedicled omentoplasty was performed, with or without split-skin graft and additional VAC therapy. Three patients only received a pectoralis plasty. We evaluated preoperative characteristics and post-operative course. Twenty-four patients (66.7%) had an uneventful post-operative course. Complications in the other patients included wound dehiscence, herniation of the donor site and infection of sternal plating material. Average sternal wound healing after sternal plating plus pectoralis plasty, pectoralis plasty and omentoplasty respectively accounted 7.7, 8.0 and 11.6 weeks. From our experience, we recommend VAC therapy plus delayed sternal plating and additional bilateral pectoralis major flap advancement as first repair option in case of DSWI. However, individual clinical conditions need to be taken into account when making a decision between the different available reconstructive options. Omentoplasty should be reserved for cases in which the sternum has recurrently fallen open after previous sternal plate refixation, or for cases in which the sternum defect is too extended.

Sternum wound contraction and distension during negative pressure wound therapy when using a rigid disc to prevent heart and lung rupture

Background

There are increasing reports of deaths and serious complications associated with the use of negative pressure wound therapy (NPWT), of which right ventricular heart rupture is the most devastating. The use of a rigid barrier has been suggested to offer protection against this lethal complication by preventing the heart from being drawn up against the sharp edges of the sternum. The aim of the present study was to determine whether a rigid barrier can be safely inserted over the heart with regard to the sternum wound edge movement.

Methods

Sternotomy wounds were created in eight pigs. The wounds were treated with NPWT at -40, -70, -120 and -170 mmHg in the presence and absence of a rigid barrier between the heart and the edges of the sternum. Wound contraction upon NPWT application, and wound distension under mechanical traction to draw apart the edges of the sternotomy were evaluated.

Results

Wound contraction resulting from NPWT was similar with and without the rigid barrier. When mechanical traction was applied to a NPWT treated sternum wound, the sternal edges were pulled apart. Wound distension upon traction was similar in the presence and absence of a the rigid barrier during NPWT.

Conclusions

A rigid barrier can safely be inserted between the heart and the edges of the sternum to protect the heart and lungs from rupture during NPWT. The sternum wound edge is stabilized equally well with as without the rigid barrier during NPWT.

Tremendous bleeding complication after vacuum-assisted sternal closure

Vacuum-assisted closure (VAC) of complex infected wounds has recently gained popularity among various surgical specialties. The system is based on the application of negative pressure by controlled suction to the wound surface. The effectiveness of the VAC System on microcirculation and the promotion of granulation tissue proliferation are proved. No contraindications for the use in deep sternal wounds in cardiac surgery are described. In our case report we illustrate a scenario were a patient developed severe bleeding from the ascending aorta by penetration of wire fragments in the vessel. We conclude that all free particles in the sternum have to be removed completely before negative pressure is used.

Effects of foam or gauze on sternum wound contraction, distension and heart and lung damage during negative-pressure wound therapy of porcine sternotomy wounds

The study was performed to compare the effects of negative-pressure wound therapy (NPWT) using gauze and foam on wound edge movement and the macroscopic appearance of the heart and lungs after NPWT. Sternotomy wounds were created in 6×70 kg pigs. Negative pressures of -40, -70, -120 and -160 mmHg were applied and the following were evaluated: wound contraction, distension and the macroscopic appearance of the heart and lungs after NPWT. Wound contraction was greater when using foam than gauze (3.5±0.3 cm and 1.3±0.2 cm, respectively, P<0.01). The application of traction to the lateral edges of the sternotomy resulted in greater wound distention with foam than with gauze (5.3±0.3 cm and 3.6±0.2 cm, respectively, P<0.001). After using foam, the surface of the heart was red and mottled, and lung emphysema and sometimes, lung rupture were observed. After using gauze, the organ surface had no markings. The study shows that foam allows greater wound contraction and distension than gauze. This movement of the wound edges may cause damage to the underlying organs. There is less damage to the heart and lungs when using gauze than foam.

Anastomotic leakage after esophageal resection: new treatment options by endoluminal vacuum therapy

BACKGROUND

Anastomotic leakage after esophagectomy is an important determinant of early and late morbidity and mortality. Control of the septic focus is essential when treating patients with anastomotic leakages. Surgical and endoscopic treatment options are limited.

METHODS

Between 2005 and 2009, we treated 6 patients who experienced an intrathoracic anastomotic leakage after esophageal resection. After all established therapeutic measures had failed, we explored the feasibility of an endoscopically assisted mediastinal vacuum therapy.

RESULTS

We were able to heal intrathoracic esophageal leakages in all 6 patients without any local complications and without the need for reoperation. One patient died because of a progressive pneumonia.

CONCLUSIONS

Endoscopic vacuum-assisted closure of anastomotic leakages may help to overcome the limitations that are associated with intermittent endoscopic treatment and conventional drainage therapy. Our preliminary results suggest that this new concept may be suitable for those patients.

Wound contraction and macro-deformation during negative pressure therapy of sternotomy wounds

Background

Negative pressure wound therapy (NPWT) is believed to initiate granulation tissue formation via macro-deformation of the wound edge. However, only few studies have been performed to evaluate this hypothesis. The present study was performed to investigate the effects of NPWT on wound contraction and wound edge tissue deformation.

Methods

Six pigs underwent median sternotomy followed by magnetic resonance imaging in the transverse plane through the thorax and sternotomy wound during NPWT at 0, -75, -125 and -175 mmHg. The lateral width of the wound and anterior-posterior thickness of the wound edge was measured in the images.

Results

The sternotomy wound decreased in size following NPWT. The lateral width of the wound, at the level of the sternum bone, decreased from 39 ± 7 mm to 30 ± 6 mm at -125 mmHg (p = 0.0027). The greatest decrease in wound width occurred when switching from 0 to -75 mmHg. The level of negative pressure did not affect wound contraction (sternum bone: 32 ± 6 mm at -75 mmHg and 29 ± 6 mm at -175 mmHg, p = 0.0897). The decrease in lateral wound width during NPWT was greater in subcutaneous tissue (14 ± 2 mm) than in sternum bone (9 ± 2 mm), resulting in a ratio of 1.7 ± 0.3 (p = 0.0423), suggesting macro-deformation of the tissue. The anterior-posterior thicknesses of the soft tissue, at 0.5 and 2.5 cm laterally from the wound edge, were not affected by negative pressure.

Conclusions

NPWT contracts the wound and causes macro-deformation of the wound edge tissue. This shearing force in the tissue and at the wound-foam interface may be one of the mechanisms by which negative pressure delivery promotes granulation tissue formation and wound healing.

Changes in cardiac pumping efficiency and intra-thoracic organ volume during negative pressure wound therapy of sternotomy wounds, assessment using magnetic resonance imaging

Knowledge on the effects of negative pressure wound therapy (NPWT) on the intra-thoracic organs is limited. The present study was performed to investigate the effects of NPWT on the volume of the intra-thoracic organs, using magnetic resonance imaging (MRI), in a porcine sternotomy wound model. Six pigs underwent median sternotomy followed by NPWT at -75, -125 and -175 mmHg. Six pigs were not sternotomised. MR images covering the thorax and heart were acquired. The volumes of the thoracic cavity, lungs, wound fluid and heart were then determined. The volumes of the thoracic cavity and intra-thoracic organs increased after sternotomy and decreased upon NPWT application. The total heart volume variation, which is inversely related to cardiac pumping efficiency, was higher after sternotomy and decreased during NPWT. NPWT did not result in the evacuation of wound fluid from the bottom of the wound. NPWT largely closes and restores the thoracic cavity. Cardiac pumping efficiency returns to pre-sternotomy levels during NPWT. This may contribute to the clinical benefits of NPWT over open-chest care, including the stabilizing effects and the reduced need for mechanical ventilation.

Changes in cardiac pumping efficiency and intra-thoracic organ volume during negative pressure wound therapy of sternotomy wounds, assessment using magnetic resonance imaging

Knowledge on the effects of negative pressure wound therapy (NPWT) on the intra-thoracic organs is limited. The present study was performed to investigate the effects of NPWT on the volume of the intra-thoracic organs, using magnetic resonance imaging (MRI), in a porcine sternotomy wound model. Six pigs underwent median sternotomy followed by NPWT at -75, -125 and -175 mmHg. Six pigs were not sternotomised. MR images covering the thorax and heart were acquired. The volumes of the thoracic cavity, lungs, wound fluid and heart were then determined. The volumes of the thoracic cavity and intra-thoracic organs increased after sternotomy and decreased upon NPWT application. The total heart volume variation, which is a measure of cardiac pumping efficiency, was higher after sternotomy and decreased during NPWT. NPWT did not result in the evacuation of wound fluid from the bottom of the wound. NPWT largely closes and restores the thoracic cavity. Cardiac pumping efficiency returns to pre-sternotomy levels during NPWT. This may contribute to the clinical benefits of NPWT over open-chest care, including the stabilizing effects and the reduced need for mechanical ventilation.

Vacuum-Assisted Closure for Successful Treatment of a Major Contaminated Gunshot Chest-Wound: A Case Report

Vacuum-assisted closure (VAC) is a well-established treatment for complicated wound infections and chronic wounds, including poststernotomy mediastinitis. The use of VAC in treating high-energy trauma has been more limited. We present a case where VAC was successfully used to treat a contaminated self-inflicted gunshot-wound of the chest and abdomen.