Long-term Outcome After Open Treatment of Severe Intra-abdominal Infection and Pancreatic Necrosis

Background  Outcome assessment after surgical treatment of intra-abdominal infections and pancreatic necrosis has concentrated on postoperative complications and survival, while long-term results have received little attention.

Objectives  To evaluate hospital costs and long-term outcome for patients undergoing open treatment of intra-abdominal infection or pancreatic necrosis and to determine whether results justify costs.

Design  Cohort study and cost-effectiveness analysis.

Setting  Referral center.

Patients  From January 1, 1988, through June 30, 1996, we used open treatment for 147 patients with pancreatic necrosis (n=75; group 1), severe intra-abdominal infections due to benign diseases (n=50; group 2), and infections due to malignant neoplasm (n=22; group 3). All surviving patients (n=92) were followed up. Fifty-seven patients in group 1, 25 patients in group 2, and 10 patients in group 3 survived.

Interventions  The effective costs of treatment per surviving patient (including restorative surgery) were calculated. The patients were interviewed, and the residence location, medical treatment, degree of recovery, functional state, and employment status were assessed. We assessed the quality of life by using the short general health survey (SF-36).

Main Outcome Measures  Costs, survival, and long-term outcome.

Results  The effective costs per survivor studied were $175000 (group 1) and $232400 (groups 2 and 3). Most patients experienced good long-term results, ie, employment status was unchanged for 69 (75%) of the patients, and the functional state was unchanged for 81 (88%) of the patients. Readmission to a hospital was necessary for 14 (15%) of the patients, and 5 (6%) required care in nursing homes. Of the patients studied, 75% described their quality of life as good. Patients in group 3 had significantly worse results for survival, functional status, and quality of life (P<.01, log-rank test).

Conclusions  Our study demonstrated that open treatment of severe intra-abdominal infection and pancreatic necrosis is a cost-effective treatment with good long-term results for most patients. However, patients with malignant neoplasms did not benefit from this therapy and, therefore, should not be treated by laparostomy.

DESPITE ADVANCES in surgical and intensive care, severe intra-abdominal infection and pancreatic necrosis are complicated by high mortality rates.¹ A variety of surgical strategies has evolved to treat these potentially lethal diseases. Operative treatment of intra-abdominal infection consists of the elimination of the focus by resection or suturing of perforated viscera, reduction of gross peritoneal contamination, and treatment of residual infection.² While elimination of the focus and reduction of contamination are accepted as conditions of successful treatment, operative procedures differ for the treatment of residual infection. The following major approaches have been developed: (1) continuous closed postoperative lavage,^3,4 (2) planned relaparotomy,⁵ and (3) open treatment by laparostomy.^6-8

Open treatment is the most expensive of all therapeutic modalities.^7,8 Because of the severity of illness in patients treated by laparostomy, intensive care is always necessary. To determine whether this substantial use of health care resources is justified, the results of treatment must be assessed.⁹ Outcome assessment after severe intra-abdominal infection and pancreatic necrosis has concentrated on postoperative complications and survival. Because long-term consequences of intensive care and operative treatment may differ substantially from short-term results, therapy should no longer be assessed only by survival; longevity and quality of life must also be considered to assess therapeutic strategies correctly.^10-12 Few publications reported the long-term outcome after surgical treatment of severe intra-abdominal infections^13-18 ; data on long-term results after open treatment are limited.^16,18

We studied the hospital costs and long-term outcome for patients who underwent open treatment for severe intra-abdominal infection and pancreatic necrosis to answer the critical question of whether results justify costs.

From January 1, 1988, through June 30, 1996, 147 patients (95 men, 52 women; mean age, 53 years; range, 23-79 years) underwent open treatment. The indication for treatment was pancreatic necrosis in 75 patients (group 1) and severe intra-abdominal infection due to peritonitis in 72 patients (groups 2 and 3). Because our hospital is a referral center for abdominal sepsis, approximately one third (35%) of all patients were referred to our department after undergoing an operation in another institution.

The conditions of all patients constituted surgical emergencies, so the patients required immediate admission to the intensive care unit (ICU). The severity of sepsis was assessed by the development of organ failure as defined by Goris et al,¹⁹ the Acute Physiology and Chronic Health Evaluation (APACHE) II score on admission, and the Mannheimer Peritonitis Index²⁰ in cases of peritonitis. Postoperative results were assessed by in-hospital mortality.

In the majority of patients with intra-abdominal infection (69%; 50 patients), the underlying disease was benign (group 2). Of all patients with intra-abdominal infection, 31% (22 patients) had a malignant disease (group 3; Table 1).

Infected necrotic tissue (82%; 62 patients) and progressive organ dysfunction despite intensive care (18%; 14 patients) were indications for operation in the patients with pancreatic necrosis. Access to the abdomen was gained by a bilateral subcostal incision. All necrotic tissue was removed by aggressive débridement; nonanatomical or wedge resections of the tail or corpus of the pancreas were performed in 45 patients because of the extension of necrosis. The abdominal wall was partially closed by suturing the anterior and posterior layers of the rectus sheath. This led to the formation of unilateral or bilateral retroperitoneal stomata, enabling permanent access to the retroperitoneum.^8,21 From the second postoperative day, continuous lavage of the retroperitoneum was performed. Reexplorations, which were conducted in the ICU, were performed through the retroperitoneal stomata to position lavage and suction catheters. Operative reinterventions were undertaken at the occurrence of complications such as bleeding or colonic necrosis. In cases of colonic necrosis, discontinuity resections of the colon with a terminal colostomy or ileostomy were performed.²²

While open treatment was our standard technique for the treatment of pancreatic necrosis, open treatment was only used for the most severe cases of intra-abdominal infection when resection of the septic focus and scheduled reoperations could not control organ failure.²³ Open treatment consisted of forming a laparostomy by leaving the midline incision open, applying continuous dorsoventral lavage, covering the viscera with plastic foils, and placing a pouch (Incise Pouch, 3D, St Paul-Minneapolis, Minn), which consisted of an adhesive foil with a plastic bag around it, around the laparostomy.²³ All lavage solution was collected in the bag and drawn into a vacuum pump. Specimens for bacteriologic sampling were obtained during reexploration in the intensive care unit. Reoperations were performed if complications occurred; most complications were fistulas. Fistulas were treated by discontinuity resections of the affected bowel whenever possible or by diversion of the intestinal contents away from the defect by a proximal enterostomy.⁷ Continuous lavage was replaced by daily manual lavage when the infection began to resolve. After the inflammatory process subsided, laparostomy incisions were allowed to heal by second intention. After contraction of the granulation tissue and reduction of the midline defect, the laparostomy was closed provisionally by mobilizing the skin from the underlying tissues and suturing it. We did not perform skin grafting.

Definitive repair of the abdominal wall and restoration of intestinal continuity in retroperitoneal stomata were performed within 1 year after discharge.^24,25 Closure of the defects caused by retroperitoneal stomata after pancreatic necrosis could be achieved easily by mobilizing and suturing the lateral abdominal muscles.²⁶ Midline defects were closed with a modified components separation technique as described by Fabian et al.²⁷

The calculations of the costs of open treatment (including later restorative procedures) were based on the number of days patients spent in the ICU and in the surgical ward and on the number of operations performed. The mean costs of therapy used for the calculations were $3450 per day for postoperative care in the ICU, $454 per day for care in the surgical ward, and $1545 per operation. To determine cost-effectiveness, we evaluated the effective costs per survivor by adding the costs incurred by all patients (survivors and nonsurvivors) and dividing the sum by the total number of survivors.²⁸

All surviving patients were examined regularly. In an interview, patients were asked about the following topics: residence location, hospital admissions, medical treatment, degree of recovery, functional and mental status compared with before the illness, and employment status.

The degree of recovery, functional status, and employment status were classified according to the criteria described by Goldstein et al.¹⁰ Functional status was assessed as active, sedentary, or severely limited.¹⁰ Patients were assigned to 1 of 5 employment groups (ie, employed, homemaker, disabled from work, retired, or unemployed).¹⁰

Abdominal pain and involuntary dietary changes were studied as disease-specific symptoms. The abdomen was examined for incisional hernias.

To assess the quality of life, all patients were asked to answer the short general health survey (SF-36).²⁹ Data on the frequency of pain (questions 21 and 22), impairment of activity (questions 3-19), depressive mood (questions 25, 28, and 35), and overall assessment of the quality of life (questions 1 and 2) were obtained. Follow-up procedures to assess endocrine and exocrine function after pancreatitis have been reported in detail.¹⁶

The comparison of continuous variables between 2 groups was based on the Wilcoxon rank sum test for 2 independent samples. The possible associations between qualitative variables were judged by χ² tests for contingency tables (log-rank test).

Survival curves were calculated using the Kaplan-Meier method. The log-rank test was used to identify significant differences between Kaplan-Meier estimates.

Of the patients who underwent open treatment for severe intra-abdominal infection or pancreatic necrosis, 92 patients survived (mortality, 37.4%). Mortality after pancreatic necrosis was significantly less than after intra-abdominal infection (24% [18/75] vs 51% [37/72]; P=.004). In patients with an intra-abdominal infection, the type of underlying disease did not influence survival (Table 2).

The main cause of death (91% [41/45]) was septic organ failure. Failure of at least 1 organ system occurred in all patients; respiratory system failure developed in all patients. Despite the different mortality rates, the APACHE II scores and organ failure rates were similar in all groups (Table 2).

When discharged from the hospital, 29 patients had enterostomies. Discontinuity resections of the colon had been performed in 6 patients after pancreatitic necrosis because of involvement of the colon. In 14 patients with an intra-abdominal infection, resections of the small bowel or colon without restoration of intestinal continuity were performed. In 9 cases, enterocutaneous fistulas had developed as a complication of intestinal exposure in the granulating laparostomy wound.

The median stay in the ICU was 30 days (37 days for survivors; 18 days for nonsurvivors). The mean additional length of hospital stay for patients who were discharged from the ICU was 32 days.

Closures of defects in the abdominal wall were performed on 67 patients. Wound infections occurred in 6 patients and were treated successfully by using local procedures, such as draining the wounds, and by administering antibiotics. Two other patients required a second operation to evacuate a hematoma. There was no mortality after reconstructive surgery of the abdominal wall. The median hospital stay was 11 days. Simultaneous repair of intestinal stomata was performed in 22 (76%) of 29 patients. In 2 of these 22 patients, anastomotic leakage occurred, but neither patient died. The median hospital stay after intestinal restoration was 16 days (in ICU, 2 days).

While reconstruction could be achieved in 20 (87%) of 23 patients in groups 1 and 2, only 2 (33%) of 6 intestinal stomata could be closed after an intra-abdominal infection of malignant origin (group 3).

Similar results were demonstrated for repair of the abdominal wall. Laparostomies were closed in 77% (63/82) of patients in groups 1 and 2 compared with 4 (40%) of 10 patients in group 3.

The rates of complete surgical restoration (ie, reconstruction of abdominal wall and closure of intestinal stomata) differed significantly between patient groups (group 1, 83%; group 2, 68%; group 3, 30%; P<.001, log-rank test). Incisional hernias developed in 6 patients (7%) in groups 1 and 2.

The effective costs per survivor were $175000 for patients with pancreatitic necrosis and $232400 for patients with an intra-abdominal infection (Table 3). The large difference was due to the significantly higher mortality after intra-abdominal infection.

Survival after 1 year differed significantly between groups (Figure 1). Although the rate of radical (R0) resections in patients with an intra-abdominal infection due to a malignant neoplasm (group 3) was 60% (6/10), only 2 patients survived longer than 2 years. Four (40%) of 10 patients in group 3 died of recurrent or progressive tumor during the first 6 months after discharge from the hospital (Figure 1). The median survival times and causes of death are listed in Table 4.

Readmission to the hospital occurred in 9% of patients in group 1, 12% in group 2, and 80% in group 3. Of the patients in groups 1 and 2, 4% needed medical help more than once a month compared with 70% in group 3. Four percent of the patients in group 1, 8% in group 2, and 40% in group 3 were forced to change their residence to nursing homes.

Of the patients in group 1, 9% were forced to change their diets, compared with 28% in group 2 and 70% in group 3. Functional and employment status differed significantly among patient groups (Table 5).

Data on frequency of pain, impairment of activity, depressive mood, and overall assessment of quality of life were obtained from the responses to the SF-36. The differences among groups were significant (P<.001) (Table 5).

Open treatment was introduced for the management of severe intra-abdominal infection and pancreatic necrosis during the late 1970s.⁶ Laparostomy was used when conventional treatment, consisting of reexplorations, did not control the infection. The main reported advantages of open treatment were complete drainage of the abdomen, reduction of intra-abdominal pressure, and avoidance of reexploration.⁶ However, severe disadvantages—evisceration, fistula formation, and the development of giant incisional hernias—were seen from the beginning of the use of this treatment. For these reasons, open treatment has not been generally accepted for the management of severe intra-abdominal infections. To reduce complications, the technique of open treatment was modified, leading to the concept of "covered laparostomy."^30,31 Schein et al³² described the "sandwich technique," which avoided intestinal protrusion and protected the viscera by suturing a polypropylene mesh to the surrounding fascia of the laparostomy.³² The introduction of commercially available opening zippers and slide fasteners simplified the covered laparostomy.³⁰ Today, closed treatment (planned or on-demand repeated laparotomy) and open and closed laparostomy are used depending on the traditions of different centers. Authors who have used open treatment agree that laparostomy should be performed only after the failure of closed treatment.⁷

For several years, there has been controversy about which treatment of severe intra-abdominal infections—conventional closed or open—offers advantages. Because the results reported did not differ substantially, a consensus evolved that good results may be achieved by all forms of treatment depending on the experience of centers performing them.³³ However, the following questions have not been answered until now:

1. Does evidence exist that open treatment compares favorably with closed treatment, and does closed laparostomy offer advantages compared with open laparostomy?

2. Is open treatment a cost-effective treatment with acceptable long-term results?

As to the first question, to our knowledge, the only nonrandomized study comparing closed and open treatment showed no advantage to laparostomy.³⁴ However, Wittmann et al³⁵ demonstrated advantages of staged abdominal repair compared with conventional therapy when the data were adjusted for prognostic factors. In our study, open treatment was used only when closed procedures did not reverse septic organ dysfunction; therefore, the results among treatment groups could not be compared. Complications reported after closed laparostomy seem to indicate advantages to this concept compared with open laparostomy, but as Wittmann et al³³ stated, a randomized multicenter study is needed to determine the value of open treatment.

As to the second question, data on hospital costs for the treatment of severe intra-abdominal infection and pancreatic necrosis are limited. When costs are compared, the great differences among countries, hospitals, and health care systems must be considered. Fenton-Lee and Imrie¹⁵ published a cost calculation of treatment for pancreatic necrosis in 1993. They evaluated the mean cost of £18441 in 10 patients. The mean length of stay in ICU was 9.5 days; 5 patients were discharged from ICU within 4 days.¹⁵ Our patients required much longer ICU stays (mean, 29.7 days), indicating a more serious course of the disease. Broome et al¹⁷ reported mean treatment costs of $45000 in patients with necrotizing pancreatitis. They calculated this amount by listing the costs for the treatment of selected patients and, therefore, underestimated the actual costs. According to Broome et al,¹⁷ true costs "may have averaged more than $100000." The costs we report are much higher. These great differences may be explained by underlying diseases and the high rates of organ failure, as well as by factors related to the health care system and the type of cost calculation that was used. A weakness of our study is that the costs of open treatment were not compared with those of conventional closed treatment.

The most important and new information from our study is the finding that long-term results after open treatment were good in the majority of patients. The percentage of patients who required permanent care in nursing homes after discharge was low (6%). Only 25% of patients experienced a worsened employment status; functional status remained unchanged in 88% of the patients. Our study confirmed the importance of assessing long-term survival.⁶ While postoperative results in patients with an intra-abdominal infection did not depend on the underlying disease, survival after 1 year differed significantly between groups 2 and 3 (P<.001, log-rank test) (Figure 1).

Our study demonstrated that open treatment of severe intra-abdominal infection and pancreatic necrosis is a cost-effective treatment with good long-term results for most patients. Our results confirm the statement by Wittmann et al³³ that open treatment is beneficial for well-selected patients when the treatment is performed at centers with experienced physicians. However, patients with malignant neoplasms did not benefit from this treatment and, therefore, should not be treated by laparostomy. A future multicenter study comparing the results of closed and open treatment should include not only the postoperative results and costs but also the long-term outcome.

Presented in part at the annual meeting of the German Surgical Society, Berlin, Germany, April 10, 1996.

Corresponding author: Stephan Kriwanek, MD, First Department of Surgery, KA Rudolfstiftung, Juchgasse 25, 1030 Vienna, Austria.