P R O S P E C T I V E R A N D O M I Z E D S T U DY
Hellenic Journal of Surgery (2016) 88:5, 314-320
Comparative Study of Wound Healing in Primary Versus Delayed Primary Closure in Contaminated Abdominal Surgery Prashant Kumar Singh, Neeraj Saxena, Devadatta Poddar, Rohit Kumar Gohil, Gaurav Patel
Abstract Aim: To determine optimal wound closure strategy in contaminated abdominal surgery. Background Data: Wound Infection in contaminated abdominal surgery is very common and affects morbidity
and mortality of patients. There is inconclusive evidence regarding superiority of two wound closure strategy i.e., primary closure (PC) and Delayed Primary Closure (DPC) in terms of wound infection. Methods: A total of 80 patients with contaminated abdominal wounds related to hollow viscus perforation were enrolled. They were prospectively randomised to have their surgical wound managed by either primary closure or delayed primary closure on fifth post op day or later if wounds were not pristine. SSI was considered if there was pus discharge from the incision site. The primary outcome measure was the incidence of wound infection and length of hospital stay. Results: The overall infection rate for a total 0f 80 cases was 30%. The pc group had a higher incidence of wound infection (42.5%) vs 17.5% (p- 0.027) and longer length of stay (LOS) (20.7 days vs 18.1 days. (p- 0.039) Conclusion: Delayed primary closure is better strategy for management of contaminated abdominal wound.it reduces
the wound infection rate and length of hospital stay. Key words: Delayed primary closure; contaminated abdominal surgery; primary closure; surgical site infection
Introduction Infection has always been a feature of human life and sepsis in modern surgery continues to be a significant problem for health care practitioner across the globe. Surgical site infection (SSI) is one of the most common hospital acquired types of infection [1,2], which is caused by contamination, especially from the enteric endogenous viscus bacteria. Surgical site infection contributes greatly to the morbidity and mortality associated with surgery [3,4], along with sequel of wound infection, like wound dehiscence and incisional hernia, can result in long term problems [5,6,7]. Post op wound infection has a significant impact on health resources and cost [8,9].
Prashant Kumar Singh, Neeraj Saxena, Devadatta Poddar, Rohit Kumar Gohil, Gaurav PatelSurgeon Surgeon Department of General & Minimally Invasive Surgery, PGIMER & Dr RML Hospital, New Delhi, India Corresponding author: Dr Prashant Kumar Singh Senior Resident, Department of Surgery, Room No-100, First Floor, OPD Building, PGIMER & Dr RML Hospital, New Delhi -110001 e-mail:
[email protected] Received 14 July 2016; Accepted 10 August 2016 Hellenic Journal of Surgery 88
Out of many risk factors influencing post-operative wound infection, the method of skin closure has been implicated as an important factor. Delayed primary closure (DPC) and Primary closure (PC) are two commonly used methods but there is no consensus as to the optimum method. Delayed primary closure (DPC) is a procedure, which aims at reducing the rate of SSI by suturing a wound later after proper dressing for 3 to 5 days. [10] The procedure was claimed to decrease bacterial contamination [11] and increase local wound resistance from increasing wound oxygenation [12] blood supply [13] from developing granulation tissue. The DPC has its own disadvantage including pain from routine dressing, necessity for later wound stitching and increased cost of treatment [14,15]. Cruse and Foord [2] found in a retrospective survey a wound infection rate of 40% among 2093 dirty wounds, but they did not specify how skin closure was performed. Three prospective randomised studies [16,17,18] for management of perforated appendicitis wound showed no advantage to DPC in terms of decreased wound infection, compared to PC whereas another retrospective study [10,11] showed DPC could more significantly reduce wound infection rate than PC. We conducted a prospective randomised trial with contaminated abdominal wounds
Comparative Study of Wound Healing in Primary Versus Delayed Primary Closure in Contaminated Abdominal Surgery 315
and hypothesised that a strategy of DPC of contaminated abdominal wound would result in a decreased rate of wound infection
Methods Patient population
A total of 80 patients attending the Surgical Emergency of PGIMER & Dr RML Hospital, New Delhi, over a period of one and a half year (November 2011 to December 2013) were recruited for the study. All patients admitted to the trauma/ emergency surgery of age >12 years and below 65 years, and were found to have contaminated abdominal wounds at the time of surgery were included in the study as per inclusion and exclusion criteria. Contaminated/dirty abdominal wounds were defined as those that involved pre-existing clinical infection, perforated viscera or traumatic wounds with viscous injury more than 4 hours from the time of injury, with retained devitalized tissue in accordance with the Centers for Disease Control criteria. The patients were randomized into two groups of 40 patients each. All consenting subjects underwent either primary or delayed primary closure as per the allocated intervention. All patients underwent conventional Exploratory Laparotomy through a midline incision and underwent definitive management of the underlying pathology. Turbid ascites were cultured and peritoneal lavage was performed with warm saline until clear effluent was restored. Tube drains were placed in the pelvis and paracolic gutter through a separate incision in the abdominal wall. The peritoneum, rectus sheath (linea alba) and fascia were closed in layers. Patients were randomized to receive one of two strategies for wound management, i.e., Primary closure (PC) or Delayed Primary Closure for appropriate wounds (DPC). For PC, wounds were closed with nylon (2-0). For DPC, wounds were packed with saline-soaked gauze and were not manipulated until postoperative day 3 (48 hours), at which time the dressing was changed using sterile technique and the wound was evaluated for closure. If the wound appeared pristine (showed no drainage), it was approximated on 6th post op day with nylon (2-0) interrupted sutures. Otherwise, if the wound was infected, it was left open and dressing changes were instituted twice a day. If a wound infection was suspected, based on the appearance or odor of the wound or systemic signs (fever, tachycardia) earlier, i.e., before postoperative day 3, the dressing was removed and the wound inspected, using sterile technique. If the wound was healthy, it was redressed. Hellenic Journal of Surgery 88
Surveillance of wound Infection
Signs of wound infection were observed in all study patients daily until discharge and subsequently in the clinic at least 1 week and 1 month after discharge from the hospital. A wound was labeled as infected when purulent drainage was observed. Both superficial incisional and deep incisional surgical site infections, as defined by Centers for Disease Control criteria, were included as wound infections. Infected wounds were opened and packed. Possibly infected wounds were observed closely and opened if purulent drainage, increasing erythema, induration, or warmth developed. The patients were followed up for surgical site infection at one week and at one month of skin closure. Demographics
The following data were collected: age, sex, duration of symptoms (time from the onset of symptoms to operation), WBC on admission, hospital Length Of Stay (LOS) and the presence of wound infection. We tabulated underlying medical conditions that could contribute to infectious complications: diabetes mellitus, AIDS, obesity (body mass index > 30 kg/m2), malnutrition (clinical observation of muscle wasting or albumin level < 2.5 g/dl), steroid use, jaundice and cardiovascular disease. Other immunocompromising diseases such as malignancy, uraemia or liver cirrhosis were not present in our patients. Statistical analysis
Assuming an alpha error of 0.05 and a beta error of 0.20, a study population of 80 patients per group was required for this study, based on assumed wound infection rates of 30% for PC group and 10% for DPC groups. The chi-square and Fisher exact tests were used to determine whether any association between the presence of wound infection and the type of skin closure existed. Mean comparisons were performed by the two-sample Student t-test. A p value of less than 0.05 was considered to be statistically significant. Data are presented as mean +/- standard deviation or as a percentage.
Results 49 the 80 patients included in our study were males and 31 were females. Mean age was 37 years (range, 18-65 years). No patient was withdrawn from the study, and there was no perioperative mortality. All 80 patients received the allocated interventions, 40 in the DPC group and 40 in the PC group. Both groups of patients were similar in terms of sex, age, and underlying medical risk factors. The majority of patients presented with pain abdomen, abdominal distension, obstipation, vomit-
316 Prashant Kumar Singh, et al.
The culture of peritoneal fluid (ascites) during operation showed no growth in 23.7 % of patients, whereas E coli was found in 38.7%, a mixture of organisms in 18.7%, Pseudomonas in 5%, streptococcus in 6.2%, Bacteroides in 5% of patients. Overall 24 out of 80 patients (30%) developed wound infection after PC or DPC. The most common organisms cultured from the wounds were Escherichia coli (61.9%), followed by Acinetobacter (23.8%), Pseudomonas (4.7%), Staphylococcus (4.7%) and 14.2% showed no growth as shown in Table 2. All patients were evaluated for signs of wound infec-
ing, etc., were dehydrated with decreased urine output, had tachycardia and abdomen showed distension, tenderness, guarding/rigidity, rebound tenderness along with absent bowel sounds. The proportion of patients with one or more risk factors was similar (DPC 7.5% vs. PC 2.5%, p= 0.383). All patients presented within 7 days of onset of symptoms and there was no significant difference in the duration of symptoms (p=0.56). The white blood cell count was raised significantly in all patients. The average WBC Count was 25.9 in DPC group and 26.0 in PC group with no significant difference between both groups (p = 0.851). These results are shown in Table 1.
Table 1. Patient Demographics. Delayed primary Closure (n=40)
Primary Closure (n=40)
p value
Male/Female
23/17
26/14
0.32
Mean age (years)
36.35
37.63
0.63
3(7.5%)
1 (2.5%)
0.38
Diabetes Mellitus.
6
3
Malnutrition
0
0
Steroid use
0
0
Cardiovascular disease
2
2
Obesity (BMI>30)
9
4
Jaundice.
0
0
HIV/AIDS
0
0
Duration of symptoms (days)
2.43
2.63
0.56
WBC count (* 1000/ul)
25.9
26.0
0.85
Risk factors Patient with > one risk factors.
Data are presented as mean +/- standard deviation or n (%). DPC=delayed primary closure; PC=primary closure; WBC=white blood cells.
Table 2. Bacteria cultured from ascites and wound pus. Ascites (n=80) DPC (n=40)
Wound pus (n=24) PC (n=40)
DPC
PC
(n=7)
(n=17)
No growth
11
8
2
2
Escherichia coli
15
16
2
11
Mixture of organisms
6
9
0
0
Acinetobacter
0
0
2
3
Bacteroides
2
2
0
0
Streptococcal species
3
2
0
0
Pseudomonas aeruginosa
3
1
1
0
Staphylococcus
0
2
0
1
DPC=delayed primary closure; PC=primary closure.
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Comparative Study of Wound Healing in Primary Versus Delayed Primary Closure in Contaminated Abdominal Surgery 317
tion at one week and then at one month. There were seven wound infections in DPC group where various signs of wound infection appeared. Thus the wound infection rate in DPC group was 7/40 (17.5%). In PC group 17/40 (42.5%) patients had wound infection. There was a significant association between wound infection and type of skin closure (DPC 17.5% vs PC 42.5, p=0.027). On evaluating the pattern of duration of stay, it was found out that the average duration of stay was 19.46 days i.e., 18.1 days in DPC group and 20.78 days for PC group, with a statistically significant difference in (LOS) length of stay (p=0.039). There was no readmission in PC or DPC group for wound infection. These results are shown in Table 3.
DiscussionDespite the creation of several programmes to decrease the incidence of surgical site infection, it remains a common complication that has a significant impact on patient recovery and medical costs. Open wound management of contaminated wounds is a practical measure that has been used for centuries [13]. Theodor Bill Roth was a proponent of open wound management in the1860s [19] and the two World Wars popularised DPC technique among military surgeons. At that time DPC was performed only after the appearance of a healthy wound, usually at 3-7 days after surgery [20]. The incidence of postoperative wound infection after laparotomy substantially increases the morbidity and mortality, and most infections occur after emergency laparotomy. Bacterial contamination of the wound during surgery is the major factor responsible for the development of a subsequent wound infection. In our study, the overall infection rate was 30%, which is well above the infection rates of 2.8% to 17% seen in western cohorts, but studies from India shows comparable results with the SSI rate to vary from 6.09% to 38.7% [21]. Such significant variations can be explained by differences in demographics, nature of infective pathology, comorbidities, emergency nature of surgery, gross intra peritoneal contamination, inadequate pre- operative preparation, delayed presentation, poor general condition of patients, and high level of sepsis. Table 3. Wound infection rate and length of stay.
WI Mean LOS (days)
DPC (n=40)
PC (n=40)
p value
7 (17.5%)
17 (42.5%)
0.027
18.15
20.78
0.039
DPC-Delayed Primary Closure; PC-Primary closure; WI- wound infection; LOS-Length of stay.
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Cruse and Foord observed in their study that older patients are more likely to develop infection in clean wounds than younger patients [2]. Similar findings were demonstrated by Mead et al, who observed an increased wound infection in patients younger than 1 year old (2.7%) or older than 50 years old (2.8%) versus those 1 to 50 years old (0.7%) [22]. However, we noticed that 25% of cases in the age group of 60-65 years developed wound infection. This is in contradiction to other studies and may be explained by a small sample size i.e., 4/80, 5% of total cases. Age, obviously is an immutable patient characteristic and even if it is a risk factor for wound infection, it appears to be at most a modest one. Our study shows that the incidence of wound infection is 17.5% in DPC group and 42.5% in PC group. This positive correlation of superiority of DPC over PC Group shows consistency with majority of the contemporary studies in India and abroad. Researchers like Paul et al in 1976 found the prevalence of wound infection in primary skin closure of 11.8% compared to 5.8% in delayed primary closure [23]. Authors like Meissener and Meiser found the prevalence of wound infection of 39% in primary skin closure compared to none in open wound treatment [19]. It has been shown that delayed primary wound closure, for selected cleancontaminated or dirty wounds reduces significantly the rate of wound infection [24]. Few other researchers like Smilanichet al [25] found the prevalence of wound infection of 27% in wounds closed primarily compared to 3% for delayed primary closure. These studies done in quite variable setups showed the superiority of the technique of DPC over PC in case of grossly contaminated wounds which are consistent with the results of our study. Researchers like Scott et al [26] studied the influence of wound closure on wound healing and found that delayed primary closure (DPC) or secondary closure of skin and subcutaneous fat in contaminated laparotomy incisions eliminates the risk of wound infection and incisional hernia. These favourable results from different quarters led to open-wound management of contaminated wounds a practical measure that has been used for centuries [13]. In all of our cases the peritoneal fluid showed gross contamination with bowel contents along with visible pus and the bacteriology of the peritoneal fluid was similar to the gut flora, which is the evident source of infection in these cases. The pus culture from the surgical site infection showed a similar bacteriological profile. In our study cross infection was not a major problem in patients treated with DPC and the organism responsible for wound infection was almost identical to that cultured from the intra operative peritoneal fluid, except that nearly 21% of the pus were Acinetobacter positive. It appears to be more likely to be nosocomial in nature.
318 Prashant Kumar Singh, et al.
Table 4 shows comparative incidence of SSI in various other studies. Author
Year
Country
No. of Operations
Incidence of SSI (%)
Cruse and Foord [2]
1980
Canada
62939
4.7
Edwards
1984
USA
20,193
2.8
Anvikar et al
1999
India
3280
6.09
Umesh s et al
2008
India
114
30.7
Mahesh c b et al [ 21]
2010
India
418
20.9
Present study
2013
India
80
30
Various researches on this subject have concluded that the offending organisms in contaminated abdomen are predominantly bacteria from the colonic flora [14]. Based on these consistent bacteriological profiles, several groups have published updated guidelines for the choice of appropriate prophylactic antibiotics in abdominal surgery [15,27]. There is a school of thought, according to which proponents consider that peri-operative antibiotic administration allows for PC of all clean contaminated cases (e.g. appendectomy wounds), despite data suggesting that contaminated wounds have a higher rate of wound infection [28]. This practice can be aggressively pursued by surgeons on the basis of its association with a “low” incidence of infective complications, the elimination of painful and time-consuming dressing changes and reduction in cost in case of clean contaminated wounds but not contaminated wound [29,30,31]. Our result favouring DPC over PC shows a continuum of researches on this important preventive aspect of SSI and is agreed upon by a host of other standard researches on this subject. Works by Grosfeld and Solit [32] in 1968 reviewed perforated appendicitis wounds and found a wound infection rate of 2.3% for DPC compared to 14.6% with PC. More recently, Lemieur and co-workers [10] found a wound infection rate in perforated appendicitis of 24% when the incision was closed primarily which is very consistent to our results. An important work done by Chiang and others in 2006 found a wound infection rate of 4.2% in DPC group
of patients with grossly contaminated abdomen (perforated appendicitis) compared with 43.9% in PC group. This result is quite comparable to our result of 42.5% in PC versus 17.5% in DPC group. The benefit in reducing SSI by DPC is due to the fact that it has the advantage of reducing the numbers of colonic bacteria, particularly anaerobes, contaminating the wound [33]. However, the disadvantage of allowing exogenous bacteria such as Staphylococci to contaminate the wounds in the ward before closure has been recognized. Table 5 summarises the results of previous four prospective randomised trials comparing DPC with PC in the literature. Some prospective studies comparing DPC to PC of dirty wounds have shown contrary results [16,17,18,34]. Still, DPC is a common technique used for dirty wounds, assuming that it lowers the rates of infection. The effect of wound infection in laparotomy wounds is devastating both for patients and health care provider. The complications and the financial impact of wound infection are also significant. Wound infection is a significant contributor for dehiscence and herniation as previously reported [7,35.] Riouet al [36] reported a wound infection rate of 45% in 31 patients with fascial dehiscence among 2,761 patients undergoing major abdominal surgery, compared with 2% in a control group. The incidence of incisional hernia after repair of wound dehiscence is as high as 45% [37]. Bucknall et al found a 1.7% incidence of burst abdomen and a 7.4% incidence of incisional hernia among 1,129 major laparotomies where wound infection was a significant
Table 5. Results of few prospective randomized studies. DPC
PC
Comments
Anderson (1972)[18]
N-58; WI-15(26%)
N-58; WI-20 (34%)
NS
Pettigrew (1981)[33]
N-42; WI- 23 (54%)
N-41; WI-15 (37%)
NS
Tsang (1992)[16]
N-25; WI-6 (24%)
N-38; WI- 8 (21%)
NS
Chiang et al (2012)[43]
N-34; WI- 1 (2.9%)
N-36; WI-16 (38.9%)
p < 0.001
Present series (2013)
N-40; WI-7(17.5%)
N-40; WI-17(42.5%)
p- 0.027
DPC- delayed primary closure; PC -primary closure; N- no of cases; WI - wound infection NS - not significant
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Comparative Study of Wound Healing in Primary Versus Delayed Primary Closure in Contaminated Abdominal Surgery 319
contributing factor [38]. The development of these post SSI complications has been analysed in detail in view of morbidity and financial consequences. Authors like Irvin et al found that dehiscence and herniation occurred in 2.5% of 163 non infected wounds and 25% of 28 infected wounds [39]. Studies done by Haddad and Macon found a 31% wound infection rate among 70 wounds with dehiscence among 18,120 major abdominal surgical procedures [40]. Necrotizing fasciitis remains a rare but potentially lethal complication of surgical wound infections. The increased incidence of significant complications associated with wound infection supports the notion that it is prudent to avoid wound infection whenever possible. On analysis of the days of hospital stay in both the groups the result was favourable towards DPC. The duration of hospital stay is directly linked to increased burden on health care delivery system, morbidity of patients, nosocomial infections and negative financial consequences. The financial impact and complications of wound infection and its sequel are significant. Davey and Nathwani [8] found excesses in hospital costs per wound infection of $600 for an inguinal hernia repair and $2,152 for colorectal surgery. The number of days of hospital stay is directly proportional to the logistic burden on health care delivery system. It has a huge impact on financial and functional efficiency of the hospital. In our study the range of hospital stay was from 11 days to 43 days with a mean duration of 19.46 days. The range of stay for DPC group was 11 to 29 days where as for PC group was 13 to 43 days,i.e. mean duration of 18.15 and 20.7 days respectively for DPC and PC groups. This result is statistically significant (p= 0.039), which clearly shows decreased hospital stay in DPC group [36]. It is also the cause for increased costs, associated with the longer hospital stay [41,42]. Our study is among few of the studies which have randomized abdominal laparotomy wounds with gross contamination to study the effects of wound closure technique i.e. PC & DPC in preventing SSI. This study in closing selected dirty wounds 4 days after surgery resulted in a significantly lower rate of infection for all wounds and decreased length of hospital stay. One limitation of the study was the difficulty in analysing the use of antibiotics, because antibiotics were used not only for serious underlying intra-abdominal infections, where the duration and type of antibiotics in part depend on the clinical response in each patient, but also for a variety of concomitant indications (e.g., pneumonia, line sepsis). Therefore, it was not ethical to restrict the use of antibiotics in accordance with a specified protocol. Other limitation was that the investigators evaluating the wound could not be masked, which may have introduced bias. Hellenic Journal of Surgery 88
In conclusion, DPC appears to decrease the rate of wound infection in dirty abdominal wounds when compared to PC. Acknowledgement: We are thankful to our head of department Dr CK Durga for her continuous support and encouragement. We are indebted to our patients who gave us the opportunity to serve then and learn the intricacies of surgical science. The study was self-funded and no grant was received. Ethical Standards: This is to declare that the manuscripts submitted for publication and the research methodology comply with the current laws of our country (India). The Study was approved by the appropriate ethics committee of our Institution and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki.All persons gave their informed consent prior to their inclusion in the study. The authors declare that there is no conflict of interest and has full control over all primary data and agree to allow the journal to review our data if requested. There is no financial relationship with any organization or sponsorship for the research.
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