Open window thoracostomy (OWT) is an invasive treatment option for thoracic empyema that is seldom indicated. These wounds are accompanied with a prolonged hospital stay and significant patient discomfort over an extended period of time. A retrospective report was conducted on patients who underwent OWT at the Academic Medical Center (Amsterdam, The Netherlands) and evaluated if topical negative pressure therapy ([TNP], V.A.C.® Therapy™, KCI Medical BV, Houten, The Netherlands) is a valid treatment option for these wounds. Clinical outcome and applied management methods are analyzed. Between January 1986 and June 2005, 15 patients, with a mean age of 54 years, were treated with OWT. Recently, the authors have used TNP in combination with OWT as a new treatment modality to obtain rapid control over pleural bacterial load and to achieve a well-vascularized wound surface. Good clinical results and a trend toward shorter hospital stays and improved quality of life were seen. Open window thoracostomy as a treatment modality for thoracic empyema is a valid option but only when other means fail or are contraindicated. Treatment of open window thoracostomy in combination with TNP is a safe and adequate therapeutic option for thoracic empyema resulting in improved quality of life and overall shorter hospital stay.

       Thoracic empyema (TE) remains a surgical challenge and is associated with substantial morbidity and mortality. In more than 50% of patients, TE is of parapneumonic origin.^1–4 After pneumonectomy TE occurs in 2%–15% of patients.^1,2,4 Although more uncommon, it may complicate any kind of pulmonary resection.^1,5 Mortality rates of up to 70% have been reported.^1,3 The presence of a bronchopleural fistula increases the morbidity and mortality of TE by providing a source of continuous contamination of the pleural space and by promoting aspiration of infected pleural fluid into pulmonary tissues.^1,5,6
       Management consists of early, adequate drainage. Closed thoracostomyand conversion to open surgical drainage followed either by a large-bore tube drainage or open window thoracostomy (OWT), are procedures that can be continued for an extended period to control infection, obliterate loculations, and heal pleural surfaces by second intent.^1,7–9 In spite of their good results and advantages, drainage, irrigation, and other promising techniques (eg, video-assisted thoracoscopic surgery (VATS), have their limitations in treating TE. They are likely to be successful in early stages. When these more conservative measures fail, a more aggressive surgical approach is indicated (eg, OWT). If the condition of the patient precludes major surgery such as surgical decortication,OWT can serve as a more valid option to control TE. Although OWT is an invasive approach with a prolonged hospital stay and major patient discomfort over a long period of time, OWT remains a therapeutic option in patients with TE.^1,6
       Topical negative pressure therapy (TNP) has gained wide acceptance in many surgical disciplines.^10–13 Topical negative pressure therapy is a closed system that applies subatmospheric pressure to wound tissue through polyurethane foam. Beneficial effects on blood flow to the wound and proliferation of granulation tissue have been reported.^14,15 The mechanism entails the removal of interstitial edema lowering capillary afterload and thereby promoting microcirculation. Also, by removing excess fluid, mitosis inhibitory factors are diminished and bacterial loads are reduced.^11,14,15 By applying vacuum,wound edges are approximated thus reducing wound size.
       A retrospective analysis of patients treated with OWT in the authors’ hospital was performed and TNP was evaluated as a treatment option in these wounds.

Methods

       Study design. A retrospective follow-up study of adult patients who underwent an OWT was carried out at the Academic Medical Center in Amsterdam, a tertiary care university hospital. Patients were selected with the aid of the International Classification of Diseases and medical records from the Cardiothoracic and Pulmonary Medicine departments. Primary points of interest were indications for OWT, surgical dressing techniques,wound defect status and surgical closing techniques, total mortality, perioperative morbidity, and total hospital and intensive care stay. Referring specialists and general practitioners were contacted for follow-up. As TNP was an experimental surgical technique, patients were properly informed and gave verbal consent. The local Medical Ethics Committee approved the study.

Open Window Thoracostomy and Topical Negative Pressure Therapy

       After pus and necrotic tissues were removed, OWT involved the resection of 2 to 4 rib segments to fully expose the empyema cavity.The skin was advanced and brought down to the parietal pleura. The pleural cavity was filled with saline-soaked gauzes. Dressings were changed at least once a day.
       Recently, the authors introduced TNP (V.A.C.^® Therapy^™, KCI Medical BV, Houten,The Netherlands). The aim was to reduce the bacterial load and promote granulation of the pleural cavity. The dressing was initially changed after 48 h, and then every 4 to 5 days thereafter. In all cases this took place on the surgical ward.A hydrocolloid adhesive (Allevyn^® Thin, Smith & Nephew BV, Hoofddorp, The Netherlands) was used to protect the skin edges. Delicate anatomical structures, such as pulmonary tissues or vessels, were covered with gauze dressings (Adaptic^®, Johnson & Johnson Wound Management,Amersfoort, The Netherlands) to minimize the risk of damage or bleeding. Several layers of polyurethane foam were trimmed to fill the pleural cavity. Depending on the patient’s body mass,the most superficial layer of foam should rise 3 cm to 4 cm above skin level when the vacuum is not in use, to allow meticulous contact of foam to wound when the system collapses on application of the vacuum. This is particularly important in patients who are likely to cough (eg, obese patients or those with chronic obstructive pulmonary disease). To avoid possible retained foreign bodies, the number of foam pieces used was written down in the medical record. The pump unit was programmed at 125 mmHg of continuous negative pressure. Intermittent pressure therapy was not used because most patients found frequent cessation of the vacuum painful. If pulmonary tissues were exposed, the negative pressure was initially set at 75 mmHg.
       If the pleural cavity showed a well-vascularized wound surface, patients were assessed for possible secondary closure of the OWT. This was especially preferred in cases of residual functional pulmonary tissues. Contraindications were persistent pathogenic bacteria, poor general health, evidence of tumor recurrence, and if a pleural cavity was deemed too large for reconstructive surgery with available muscle flaps.
       General indications for OWT are described in Table 1.

Table 1.

Results

       Patient characteristics. Between January 1, 1986 and June 1, 2005, a total of 277 patients were treated for TE at the authors’ hospital. Open window thoracostomy was performed on 15 patients of whom 9 had postpulmonary resection TE. Following pulmonary resection the incidence of TE was 1.8% (507 major pulmonary resections). During the study period, 15 patients (12 men and 3 women) with a mean age of 54 years (range of 22–74 years) underwent OWT. Mean body mass index (BMI) was 23 with a range of 16–33. Signs of an altered immune status were frequent and included malnutrition (33%) and use of immunosuppressive medication (33%). Other comorbid conditions were chronic obstructive pulmonary disease (n = 4), diabetes (n = 3), and substance abuse (n = 3). Other risk factors for poor wound healing were radiation therapy (n = 2), chemotherapy (n = 1), and radiation and chemotherapy combined (n = 2).
       Following diagnosis of TE, mean total hospital stay was 81 days (range 32–181 days). Mean intensive care stay was 27 days. Mechanical ventilation with average duration of 23 days was indicated in 10 patients. Mean postoperative hospital stay was 47 days.
       Indications for open window thoracostomy. The main indication was TE (n = 13). In most cases there was an associated bronchopleural or esophagopleural fistula (n = 11). Indications for OWT are described in Table 2. Left-sided OWT was done in 8 patients and right-sided in 7 patients. The procedure was performed after initial diagnosis of TE with a mean interval of 104 days with a range of 11–645 days.

Table 2.

       Topical negative pressure therapy. Five patients were treated with TNP and had good clinical results. Mean hospital stay after OWT was 43 days. In patients not treated with TNP, mean hospital stay after OWT was 48 days.The mean duration of TNP was 35 days. No complications were seen. The OWT closed spontaneously in 1 case. In other patients, the OWT remained open and the TNP-treated patients were discharged with daily dressing changes. Within 3 months after discharge,OWT was successfully closed surgically in 2 patients.
       Follow-up and closure. Follow-up was complete in all patients. Mean follow-up was 4.3 years (range 53–3350 days).
       The defect eventually closed spontaneously in 3 patients. Two patients died before surgical closure could be considered. In 4 patients, the thoracic defect remained intermittently infected due to a large bronchopleural fistula. In these cases, surgical closure was judged too great a risk for recurrence of TE. In 1 patient, closure was not possible due to poor general health. In another patient, no muscle flaps were available to fill the pleural cavity.

Figures 1a and 1b

       Closure of OWT using reconstructive surgical techniques was successful in 3 patients of which 2 were treated with TNP. In these 3 cases the bronchopleural fistula closed spontaneously. In 2 cases a muscle flap was used—in 1 patient the rectus abdominis muscle, and in another, the pectoral muscle. In a third patient, only a cutaneous flap could be used to close the thoracic defect because no muscle flaps were available for transposition.
       Mortality. Between January 1, 1986 and June 1, 2005, 7 patients died (47%) after a mean of 4.7 years (range 53–3350 days). Fiveyear survival after OWT was 73%. One patient died before discharge (7%). The causes of death were metastatic malignant disease (n = 3), respiratory failure (n = 3), and renal failure (n = 1).All patients treated with TNP are still alive.

Discussion

       Thoracic empyema continues to be surgically challeng-ing and is associated with high morbidity and mortality rates.Adequate pleural drainage remains the key to effective treatment of TE. Failure to adequately evacuate the pleural space or presence persistent signs of infection is an indication for prompt and aggressive surgical intervention.^1,7–9
       More recently, good results for minimally invasive surgical techniques with advantages in terms of postoperative care have been reported.^1,2,5,16 Video-assisted thoracoscopic surgery is a promising technique for surgical drainage of TE.^1,2,5,16
       Over a period of 19 years, OWT was indicated in 15 patients. Although rare, prolonged hospital and intensive care stay and prolonged mechanical ventilation was seen. All but 1 patient were discharged in good condition.
       Closure of bronchopleural fistula occurs spontaneously in one-third of cases,¹ but can be achieved in most of patients by aggressive surgical intervention involving re-closure of the bronchial stump and transposition of omentum and/or vascularized muscle flaps. These surgical interventions to obliterate the residual empyema space are successful in 80% of cases.¹⁷ Muscles used for intrathoracic muscle transposition or thoracomyoplasty include the pectoralis major and minor, serratus anterior, rectus abdominis, and the latissimus dorsi.^1,17,18
       In this case series, the thoracic defect closed spontaneously in 3 patients. In 3 patients, OWT was successfully closed using surgical reconstructive techniques.
       Topical negative pressure therapy has become a first line management in many wounds.^11–13 Five patients were treated with TNP and no complications were seen. A trend towards shorter hospital stays was observed as hospital stay after OWT declined from 48 to 43 days. Use of TNP resulted in rapid proliferation of healing granulation tissue and lower bacterial loads.TNP-treated patients also reported an increased level of comfort. No complications such as bleeding, pulmonary laceration, or air leakage due to a large bronchopleural fistula were seen.For these reasons,OWT followed by TNP is a valid option for treating TE and could facilitate surgical closure of the thoracic defect. As more experience is gained with TNP, the authors expect to see further decline in hospital stays. An additional advantage was less discomfort for the patient as daily traditional dressing changes are more painful.
       This technique should only be used in more chronic conditions, as initially there is a theoretical risk of mediastinal shift in postpneumonectomy patients. Special attention is mandatory as anaerobes are frequently isolated pathogens.
       Open window thoracostomy as a treatment modality for TE remains a valid option, but only when other means fail as it carries high morbidity rates and a prolonged hospital stay. Treatment of OWT in combination with TNP is a safe and adequate therapeutic option for TE resulting in a shorter hospital stay and improved quality of life.