Infections at the surgical site continue to occur in as many as 20% of elective colon resection cases. Methods to reduce these infections are inconsistently applied. Surgical site infection (SSI) is the result of multiple interactive variables including the inoculum of bacteria that contaminate the site, the virulence of the contaminating microbes, and the local environment at the surgical site. These variables that promote infection are potentially offset by the effectiveness of the host defense. Reduction in the inoculum of bacteria is achieved by appropriate surgical site preparation, systemic preventive antibiotics, and use of mechanical bowel preparation in conjunction with the oral antibiotic bowel preparation. Intraoperative reduction of hematoma, necrotic tissue, foreign bodies, and tissue dead space will reduce infections. Enhancement of the host may be achieved by perioperative supplemental oxygenation, maintenance of normothermia, and glycemic control. These methods require additional research to identify optimum application. Uniform application of currently understood methods and continued research into new methods to reduce microbial contamination and enhancement of host responsiveness can lead to better outcomes.
Elective colon surgery continues to have the highest rate of infection at the surgical site among all elective surgical procedures. These infections span a continuum of mild superficial infection to those that are deep-seated within the abdominal cavity and pose a serious threat to the patient’s survival. These infections are associated with considerable patient morbidity as a general rule and frequently require reoperation, prolonged hospitalization, and readmission to the hospital during the course of management. Surgical site infection (SSIs) have proven to be very costly in addition to the attendant patient morbidity [
Because of the frequency and severity of these infections, there has been nearly a full century of efforts to define improved processes for prevention. Numerous methods have been proposed and employed before and during elective colon surgery to prevent infection at the surgical site. Many have strong scientific foundation, while others are driven solely by expert opinion. This presentation will attempt to provide a comprehensive context of the pathogenesis of SSI following elective colon surgery and to define those methods that have evidence to support use for prevention.
In past decades it has been the practice to refer to wound infections as separate entities from infections that occur in the abdominal cavity following colon resections. In recent years, it has become preferable to refer to all infections at the surgical site as SSIs. The infections are divided into three categories of superficial, deep, and organ/space infections (Table
Definitions of superficial, deep, and organ/space SSIs as defined by the National Healthcare Safety Network. The comments are specifically applied to elective colon surgery.
Definition | Comments specific for elective colon surgery |
---|---|
|
(1) There are two specific types of superficial incisional SSIs. |
| |
|
(i) There are two types of deep incisional SSIs. |
| |
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(i) Because an organ/space SSI involves any part of the body (excluding skin incision, fascia, or muscle layers) that is manipulated during the operative procedure, criterion for infection at these body sites must be met in addition to the organ/space SSI criteria. |
SSIs occur as the summation of four different clinical variables in patients undergoing colon surgery. First, the
While the colonic lumen is the major source of bacterial contamination of the surgical site, colonic surgery is subject to all of the generally recognized other sources of bacterial contamination as well. Skin colonization can be a source that accounts for the smaller percentage (<20%) of infections that are from gram positive organisms.
A second clinical variable that leads to SSI is the virulence of the organisms that contaminate the wound. Specific strains of bacteria have different virulence characteristics depending upon the exotoxins they produce or the character of the endotoxins in the cell wall. Aerobic gram negative organisms (e.g.,
Environmental factors at the surgical site can decrease the number of bacteria necessary to cause SSIs, and accordingly increase rates of infections. Hemoglobin and hematoma in the surgical incision increase SSI by providing bacterial contaminants with a rich supply of ferric iron to enhance microbial replication [
The fourth variable in SSI rates following elective colon surgery is the effectiveness of
There are two components of the host response. There is the intrinsic, genetically program responsiveness that is poorly understood and not likely to be manipulated by preventive strategies. This was best illustrated by Sorensen et al. [
An important but infrequently discussed aspect of SSI is the organ/space infections. In colon surgery, this is specifically the occurrence of intra-abdominal infection following resection and anastomosis. Like the surgical incision, the intra-abdominal cavity is exposed to a vast number of microorganisms at the time of surgical entry into the colon lumen. Microbial contaminants bind to the peritoneal surface, and in the majority of cases the organisms are eradicated by the innate host response.
Two circumstances may lead to the organ/space infection. First, the quantity of bacterial contamination may exceed the capacity of the host for clearance. Dense quantities of bacterial contamination that are potentially the consequence of spill of colonic contents during the procedure will ordinarily aggregate into the physiologic drainage basins of the abdominal cavity; specifically, the subphrenic/subhepatic space, the pelvis, or the paracolic gutters. These dependent areas also collect serous fluid and hematoma from the operation, which serve as environmentally enhancing variables for infection in the same way that infection occurs within the incision itself. Abscess is the consequence.
The second circumstance for organ/space SSI is failure of the anastomosis and postoperative leakage. These leakage events are likely to occur in 3–6% of all colon anastomoses, but have higher rates when reviewing anastomosis following anterior rectal resections [
(a) Demonstrates an abdominal abscess on the right side of the abdomen following a right hemicolectomy. (b) Demonstrates a large pelvic abscess from a leaking anastomosis following a rectosigmoid colectomy.
In summarizing the discussion on pathogenesis, it must be emphasized that there are numerous clinical variables that contribute to SSI as an outcome following colon surgery (Table
Identifies the patient risk factors and the treatment-related risk factors that influence SSI rates in patients undergoing elective colectomy.
Patient risk factors | Treatment-related risk factors | ||
---|---|---|---|
Advanced age | Obesity | Length of operation | Hair removal strategy |
Alcoholism | Drug abuse | OR traffic | Glove/barrier failure |
HIV disease | Chronic liver disease | Poor antibiotic timing | Wrong antibiotic choice |
Chronic renal disease | Corticosteroids | Intraoperative “spill” | Excessive electrocautery |
Chronic tobacco use | Diabetes | Skin antiseptics | Adhesive drapes |
Hyperglycemia | Chronic lung disease | Contaminated instruments | Contaminated irrigation solution |
Hypoalbuminemia | Malignancy | Preoperative showers | Braided suture material |
Nasal colonization | Preoperative nursing home | Excessive traction/wound trauma | Wound dead space |
Chronic hemodialysis | Recent hospitalization | Transfusion | Drains |
Presence of stoma | ASA score | Wound hematoma | Glove starch |
Resistant Bacterial Colonization | Virulent colonization | Intraoperative hypothermia | OR air handling systems |
Prehospitalization antibiotics | Inflammatory bowel disease | Antibacterial sutures | Wound sealants |
Prior surgical site infections | Preoperative anemia | Patient controlled analgesia | Pulsed-lavage of the surgical site |
Nonsteroidal anti-inflammatory agents | Recent weight loss | Mechanical bowel preparation | Oral antibiotic bowel preparation |
When SSI occurs following colon surgery, it can be anticipated that the bacteriology of the infection will be those organisms that contaminated the site at the time of the operation. For most colon procedures,
Organ/space infections have similar patterns of identified pathogens. Because abscesses or diffuse peritonitis are direct consequences of intraoperative or luminal contamination, the bacteriology of these abscesses reflects the normal colonization of the human colon and makes
A key feature in an overall strategy to prevent SSI in the colon surgery patient is to have an effective surveillance program. A consistent and vigilant surveillance effort will permit the surgeon and the institution to monitor the overall rates of infection. With surveillance an objective decision can be made about improvements in outcomes, but also when clusters of infections are occurring and indicate that infection control practices need to be reviewed and modified. As is illustrated in Table
The most common single diagnostic sign of SSI is the discharge of pus from the surgical incision. Many will use this as the only true measure of an SSI. Others will use erythema and induration of the wound, but these criteria suffer from erythema commonly being associated with an inflammatory response to stapled wound closures, and induration may or may not be detected at all in patients with a thick fat layer in the abdominal wall. Wounds may have the discharge of serous drainage which may or may not be proven culture positive for a light growth of an unlikely organism such as
Rates of SSI in colon surgery, or any other operative procedure, cannot be compared across different institutions. Different definitions are used in different hospitals. The intensity of surveillance during the hospitalization will mean that those hospitals with the greatest diligence will have the highest apparent rates. Most importantly, most SSIs following colon surgery are not identified until after the patient has been discharged. Hospital based surveillance programs will not capture the postdischarge event and require special efforts to capture infectious complications after the patient leaves the hospital [
This illustrates the reported rates of SSI following colectomy for each of the NHSN index risk scores.
Furthermore, different patient populations represent different risk profiles in different institutions and apparent differences may not be an equitable comparison. A somewhat simplified risk adjustment method is to use the NHSN system which segregates patients into four risk tiers depending upon the degree of intraoperative contamination, the American Society of Anesthesiologist severity score (Table
Descriptor of the six categories that currently comprise the American Society of Anesthesiology Physical Status Classification System*.
ASA score | Description of classification | Patient example |
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1 | Normal healthy patient | A 21-year-old, well-conditioned male athlete undergoing elective groin hernia repair |
2 | Patient with mild systemic disease | A 46-year-old woman with mild but controlled hypertension undergoing a laparoscopic cholecystectomy |
3 | Patient with severe systemic disease | A 53-year-old man with insulin-dependent diabetes and coronary artery disease undergoing elective aortofemoral bypass |
4 | Patient with severe systemic disease that is a constant threat to life | A 62-year-old woman on chronic renal hemodialysis undergoing emergency laparotomy for perforative diverticulitis |
5 | Moribund patient who is not expected to survive without the operation | A 58-year-old man with morbid obesity, type 2 diabetes, and shock, undergoing extensive debridement for streptococcal necrotizing fasciitis |
6 | Patient declared brain-dead whose organs are being removed for donor purposes | A 35-year-old male motorcycle accident victim with brain death and normal cardiac function, for multiorgan thoracic and abdominal organ donation |
Public reporting of SSI rates for colon operations and other procedures has become a common goal of government and selected healthcare quality organizations. Guidelines for public reporting have even been issued [
The prevention of SSIs in colon surgery requires the implementation of a host of preoperative and intraoperative measures. Patients undergoing colon surgery have potentially many risk factors for infection, and infection can occur from any number of specific events during the procedure (Table
Preoperative measures for elective colonic surgery begin with preparation of the surgical site. Considerable interest has been focused upon preoperative bathing, showering, and/or scrubbing of the proposed surgical site with antiseptic soap and/or antiseptics. Despite a host of clinical studies, meta-analyses have not demonstrated a reduction of SSI rates in clean operations or in any group of aggregated operations [
The classic studies of Cruse and Foord [
Follicles of hair at the surgical site have always been viewed as a risk for bacteria and SSI. However, there is no evidence to support hair removal and a subsequent reduction in SSI rates [
The three major antiseptic solutions that are used for the preparation of the incision site have been chlorhexidine, povidone iodine, and isopropyl alcohol. The published guidelines from the CDC have not endorsed one skin preparation over the alternatives [
An emerging trend has been to combine chlorhexidine (2%) with isopropyl alcohol (70%) for skin preparation. The alcohol evaporation accelerates the drying of the chlorhexidine at the time of application. A randomized trial of chlorhexidine-isopropyl alcohol compared to povidone iodine alone demonstrated a significantly lower SSI rate (16.1% versus 9.5%,
Plastic adherent drapes that are applied to the skin at the site of the incision have been used for a period of time to prevent residual skin colonization following antiseptic preparation from accessing the surgical site during the procedure. Early studies have actually reported higher infection rates with these plastic adhesive drapes which were likely due to a “greenhouse” effect of perspiration and microbial proliferation beneath the plastic [
A variation of the plastic drape is to use a cyanoacrylate skin sealant. The proposed surgical site is cleansed, the topical antiseptic is applied, and the antiseptic is allowed to completely dry. The topical cyanoacrylate sealant is then applied and it too is allowed to dry before the incision is then made through the seal. The concept is to seal residual skin microflora not cleansed by the preoperative skin preparation so that contamination will not occur during the remainder of the procedure. There is evidence to support this practice in clean operations [
Another variation on the theme of a plastic drape is to use a ringed wound protector which is actually inserted into the abdomen, and the plastic drapes which are connected to a synthetic ring are then brought out of the abdomen to protect the wound interface after the incision. Such a strategy would make sense for incisional protection when the contamination is arising from within the abdomen during colon surgery. A meta-analysis has identified a benefit to these wound protectors [
The use of preventive antibiotics in elective colon surgery is generally viewed as the most significant method that has improved outcomes. With the introduction of antibiotics into clinical practice following World War II, the use of antibiotics to avoid infection in colon surgery was of particular interest because of the high rates of SSI that were observed in these patients. This enthusiasm for preventive antibiotics rapidly dissipated when clinical trials in colon surgery and other operative procedures failed to demonstrate any reduction in SSI rates. The two major issues that influenced the failure for SSI reduction were the timing of administration of the antibiotic and the failure to stratify the operative cases by risk. At that time the antibiotics were given following the operation, and cases with high rates of infection (e.g., colon surgery) were studied with cases that had low rates of infection (e.g., inguinal hernia repair) which led to overall infection rates aggregating to the mean regardless of the preventive strategy.
The influence of timing upon antibiotic prophylaxis in surgery was identified in experimental studies by Miles et al. [
Polk and Lopez Mayor did the first clinical study of clean-contaminated elective surgical case with 50% colon procedures that demonstrated a statistically significant reduction in SSI rates by administration of the antibiotic (cephaloridine) before the surgical incision [
Following these pioneering clinical trials there were a large number of reported studies that further validated the benefits of preoperative administration of preventive antibiotics. Baum and associates demonstrated the compelling results of the numerous placebo-controlled trials which showed the benefit of preoperative preventive antibiotics in colon surgery, and concluded that no further placebo-controlled trials should be performed [
An important consideration is to understand why antibiotics given after wound closure do not improve SSI rates. Bacterial contamination on the incisional interface or over the peritoneal lining cells is promptly embedded in fibrin as part of the inflammatory response to tissue injury. During the course of the operation, the contamination of the surgical site continues from the multiple potential sources and the activation of fibrin from inflammation similarly occurs. At wound closure, the subcutaneous tissues and skin are closed and the residual wound space is also promptly populated by fibrin leaving a dense protein matrix with entrapped microbes. The fibrin matrix is impervious to systemic antibiotics from the circulation. Antibiotic effect in reduction of viable microbial counts requires that the drug must be present at the time that the fibrin is produced from the serum proteins. Antibiotics administered following the precipitation of the fibrin do not make contact with the surgical site contamination. Furthermore, the normal edema process of the activated inflammatory response continues after wound closure which results in a “halo” of increased hydrostatic pressure in the tissues about the closed incision. This makes the wound interface following closure a functionally ischemic area that excludes antibiotic delivery.
Appropriate preventive antibiotic selections for elective colon surgery are detailed in Table
These are the preventive antibiotic choices that are currently recommended by the Surgical Care Improvement Project. The advantages and disadvantages are the authors opinion.
Drug choice (dose) | Advantages | Disadvantages |
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Cefoxitin (1 g) | Low toxicity cephalosporin with many years of use for prophylaxis; aerobic and anaerobic coverage. | Short biological elimination half-life (45 min); concerns about gram negative resistance. |
Cefotetan (1 g) | Low toxicity cephalosporin with many years of use for prophylaxis; aerobic and anaerobic coverage. Long biological elimination half-life (4 hr) | Concerns about gram negative resistance. |
Ampicillin/sulbactam |
Extensively used penicillin with a beta-lactamase inhibitor; good anaerobic coverage. | Short biological elimination half-life (1 hr); emerging |
Ertapenem (1 g) | Extended gram negative coverage (not |
Expense. |
Cefazolin (1 g) and metronidazole (500 mg) | Good bacteriological coverage of anticipated pathogens | Limited clinical data to show effectiveness in elective colon surgery |
Cefuroxime (500 mg) and metronidazole (500 mg) | Good bacteriological coverage of anticipated pathogens | Limited clinical data to show effectiveness in elective colon surgery |
Aminoglycoside (gentamicin or tobramycin; 1 mg/kg) and clindamycin (300–600 mg) | A good choice for patients needing extended gram negative coverage (e.g., nursing home patients) | Unpredictable aminoglycoside pharmacology. |
Quinolone (ciprofloxacin; 500–750 mg, or levofloxacin; 500–750 mg) and clindamycin (300–600 mg) | Comprehensive antimicrobial coverage of anticipated pathogens. | Limited data to validate use for prophylaxis in elective colon surgery |
Aztreonam (1 g) and clindamycin (300–600 mg) | Good antimicrobial coverage of anticipated pathogens. | Aztreonam has no gram positive coverage and should not be used with metronidazole |
Aminoglycoside (gentamicin or tobramycin; 1 mg/kg) and metronidazole (500 mg) | A good choice for patients needing extended gram negative coverage (e.g., nursing home patients) | Unpredictable aminoglycoside pharmacology. |
Quinolone (ciprofloxacin; 500–750 mg, or levofloxacin; 500–750 mg) and metronidazole (500 mg) |
A second consideration in the use of preventive antibiotics is the biological elimination half-life of the antibiotic. Short half-life antibiotics can be cleared rapidly and no surgical site protection may be available especially in operations that are extended for more than two hours. The issue of half-life is not only an issue relative to the length of the operation, but is also a variable in preoperative antibiotic administration that may occur 2-3 hours before the incision. It is recommended that the antibiotic selection be given as close to the time of incision as is possible to extend the duration of drug effect after the procedure is initiated. For
Another issue that is commonly discussed but for which there is a paucity of data is the dosing of the antibiotic. Traditional dosing has been to use the same dose for all patients. The general increase in the body-mass index (BMI) of patients has raised the concern that the expanded volume of distribution of the drug in larger patients may yield inadequate incisional concentrations [
While the prevalence of gram positive SSIs is a smaller percentage than those infections due to colonic bacteria, the emergence of the community-acquired methicillin-resistant
While the use of preoperative preventive antibiotics in elective colon surgery is generally accepted, there is considerable disagreement about the proper colon preparation or whether the colon should undergo preparation at all in this clinical setting. With the advent of improved anesthesia and blood replacement therapy in the 1930s, efforts in colon surgery advanced. Infection within the incision and within the abdominal cavity proved to be the major complications of care. The high inoculum of bacteria within the colon lumen was appreciated as the problem and this led to mechanical bowel preparation as a potential solution to postoperative infections in these patients. From the late 1930s and the early 1940s it was understood that mechanical bowel preparation did not reduce the concentration of bacteria within the colon and did not reduce SSI rates! With the introduction of sulfa compounds, the research efforts were launched to use orally-administered poorly-absorbed antibiotics to reduce the concentration of intraluminal bacteria [
During the 1950s and 1960s, varying oral antibiotics and varying mechanical preparations were used following the apparent failure of the sulfa compounds that were used. The aminoglycoside antibiotics of streptomycin [
In the early 1970s, a greater appreciation of the role of anaerobic bacteria in polymicrobial infections emerged [
Using a similar rationale for coverage of colonic anaerobes as well as enteric coliforms, Washington et al. [
In 1977, Clarke et al. [
These data led to a general acceptance of the oral antibiotic bowel preparation for elective colon surgery in the U.S. Because of the parallel evolution of both the antibiotic bowel preparation and systemic preoperative preventive antibiotics in the 1970s, there was a general acceptance for using both methods together. Randomized trials of patients receiving systemic antibiotics or a placebo when patients in both arms received the oral antibiotics demonstrated reduced SSIs for both methods being used together [
This is a summary of studies comparing the oral antibiotic bowel preparation plus systemic antibiotics versus systemic antibiotics alone in elective colon surgery. Only studies with a total study population of 100 or more patients are included. The oral antibiotics used are indicated.
Author, (year) | Combined antibiotics received | Oral and IV antibiotics | IV Antibiotics only | Comments | ||
---|---|---|---|---|---|---|
SWI | No. of patients | SWI | No. of patients | |||
Kaiser et al. (1983) [ |
Neo-erythro | 2 (3%) | 63 | 7 (12.5%) | 56 |
|
Lau et al. (1988) [ |
Neo-erythro | 3 (5%) | 65 | 5 (7.5%) | 67 | No statistical difference |
Coppa and Eng (1988) [ |
Neo-erythro | 9 (5%) | 169 | 15 (11%) | 141 |
|
Reynolds et al. (1989) [ |
Neo-metro | 9 (8%) | 107 | 26 (12%) | 223 | No statistical difference |
Khubchandani et al. (1989) [ |
Neo-erythro | 5 (9%) | 55 | 14 (30%) | 47 |
|
Taylor and Lindsay (1994) [ |
Ciprofloxacin | 17 (11%) | 159 | 30 (18%) | 168 |
|
McArdle et al. (1995) [ |
Ciprofloxacin | 8 (10%) | 82 | 20 (23%) | 87 |
|
Lewis (2002) [ |
Neo-metro | 5 (5%) | 104 | 17 (16.5%) | 103 |
|
Thus, considerable evidence supported the use of mechanical bowel preparation as a method to facilitate the delivery of intraluminal concentrations of orally administered antibiotics to reduce SSIs. The mechanical preparation employed was an intense 2-3 day preparation which often was completed with a day or two of hospitalization before the elective procedure (Table
Demonstrates the choices of mechanical bowel preparation that has been employed in those studies where the oral antibiotic bowel preparation has been demonstrated to be effective. There are many variations on these protocols.
Washington et al., 1974 [ |
Nichols et al., 1973 [ |
One day preparation |
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(i) Residue-free diet for 48 hours before operation. |
(i) Day 1: low residue diet; Bisacodyl, 1 capsule orally at 6 p.m. |
|
In this setting came a rush of publications that condemned the mechanical bowel preparation as being unnecessary. Prospective randomized trials flourished in Europe to validate the observations of Poth from over 70 years ago; specifically, that mechanical bowel preparation alone does not reduce SSIs (Table
A summary of the prospective randomized trials of no mechanical bowel preparation versus patients receiving mechanical bowel preparation in elective colon surgery 2000–2010. Some reports include all surgical site infections (*), whereas others include only surgical incision infections (**). Only one article concludes that there is a statistically significant difference in infection rates, which is higher in mechanically cleansed patients.
Author (Year) | No mechanical preparation | With mechanical preparation | Statistical significance | ||
---|---|---|---|---|---|
No. of patients | Infections | No. of patients | Infections | ||
Miettinen et al. (2000)* [ |
129 | 20 ( |
136 | 13 ( |
Not significant |
Bucher et al. (2005)* [ |
75 | 6 ( |
78 | 17 ( |
|
Fa-Si-Oen et al. (2005)* [ |
125 | 13 ( |
125 | 16 ( |
Not significant |
Ram et al. (2005)** [ |
165 | 10 ( |
164 | 16 ( |
Not significant |
Zmora et al. (2006)* [ |
129 | 17 ( |
120 | 15 ( |
Not significant |
Jung et al. (2007)* [ |
657 | 106 ( |
686 | 103 ( |
Not significant |
Contant et al. (2007)** [ |
684 | 96 ( |
670 | 90 ( |
Not significant |
Pena-Soria et al. (2008)* [ |
64 | 11 ( |
65 | 19 ( |
Not significant |
Van’t Sant et al. (2010)** [ |
213 | 36 ( |
236 | 39 ( |
Not significant |
Prospective randomized trials that have addressed the issue of oral antibiotics combined with the mechanical bowel preparation have largely been absent from the published literature. Lewis published a well-controlled trial which compared oral neomycin and metronidazole versus a placebo in elective colon resections where patients in both arms of the study received systemic amikacin and metronidazole [
It is important to emphasize the correct methods to be employed in using the antibiotic bowel preparation. The mechanical preparation must be complete since the bacterial burden from unevacuated stool will negate the effective antibacterial action at the mucosa of the colon. Administration of the oral antibiotics before mechanical preparation is complete will result in the antibiotic tablets/capsules passing undissolved through the colon with no benefit to the patient. Most investigators do not believe that there is benefit to the choice of the mechanical preparation, but one study identified lower SSI rates when a phosphate-based preparation was used [
There are many questions to be answered in the strategy of oral antibiotic bowel preparation. What is the best mechanical agent that will evacuate the colon completely and in a timely fashion, but without excessive discomfort for the patient? Is neomycin really necessary in the oral antibiotic regimen? One study suggests that neomycin may not be of value [
Inoperative management of the surgical site is a critically important consideration in the prevention of SSI in elective colon surgery. While the use of antimicrobials in the perioperative period has been shown to reduce SSIs, there has been almost an exclusive dependence upon antimicrobial use to the exclusion of other methods. In the words of Altemeier from 1958, “the evidence clearly indicates, however, that antibiotic therapy cannot be depended upon to prevent the development of local infection if established surgical principles or important technical details have been ignored [
The local environment of the surgical incision is an important factor in determining whether SSI is an outcome, and these local conditions are dictated by the technical methods employed by the surgeon during the operative procedure. Minimizing tissue injury both within the incision and within the abdomen is important to prevent SSI. Overly aggressive traction creates tissue injury and rough handling of the intestine leads to local inflammation, increased risk of leakage, and organ/space SSI. Prevention of blood and hematoma requires effective hemostasis. However, over aggressive use of suture material introduces foreign bodies into the wound. Braided, nonabsorbable suture material such as silk should be avoided in the surgical incision. Excessive use of the electrocautery will leave necrotic areas within the wound and within the abdominal cavity and will result in increased infection rates. Bipolar devices have been useful in achieving the objectives of hemostasis but without excessive tissue injury. The electrocautery can be used as an alternative to the surgical knife without an increase in infection rates [
Air-borne bacteria as a source of wound contamination have been a long-standing concern of surgeons. Lister reputedly aerosolized carbolic acid in the operating room to remove bacterial fallout. Over 50 years ago, interest emerged in the use of ultraviolet light in the operating room to eliminate microbes in the air. An extensive multicenter study was conducted which showed no benefit to ultraviolet light use [
Over the last 10 years, antibacterial suture material has been developed for the closure of the fascia and the subcutaneous tissues of the surgical site. Absorbable braided and monofilament sutures are coated with the antiseptic triclosan. Triclosan is a commonly used antiseptic that is contained in cosmetics and other products. It has a long record of being safe for human use [
Irrigation of the surgical site is part of surgical lore, and in no place is it more evident than in elective colon surgery. Saline irrigation or irrigation with various antimicrobial or antiseptic agents has been used for decades. There is experimental evidence that contamination of a wound followed by local application of antibiotics may result in reductions in infection rates; there is no convincing clinical evidence that irrigation with antibiotics or other antimicrobial agents are of value. There is certainly no data to support topical antimicrobial irrigation if appropriate systemic antibiotics have been used. As for saline irrigation, there is reason to believe that irrigation will remove clot and fibrinous debris from the peritoneal cavity and from the surgical incision.
There has been interest in recent years about the utilization of pulsed lavage in contaminated wounds. The theory is that pulsed-lavage with its “jet stream” of force will remove the fibrin peel from the peritoneal cavity, from the interface of the surgical incision, or from other contaminated or infected tissue surfaces [
Experimental studies have documented the potential benefits of supplemental oxygen in the prevention of infection of the soft tissues following bacterial contamination [
Pryor et al. [
Belda et al. [
There have now been additional multiple studies in multiple different areas in using supplemental oxygen [
Hypothermia during operative procedures has been associated with problems of hemostasis and in the experimental laboratory with impairments of phagocytic function. Kurz et al. [
Until recently, there has been little evidence to either support or refute the merits of maintaining normothermia in elective colon surgery, but nevertheless it has been adopted as a process measure by the U.S. Surgical Care Improvement Project (SCIP). In a retrospective study of case matched patients, Lehtinen et al. challenged whether normothermia prevented SSIs in elective colorectal surgery [
Infectious complications in surgical patients have been associated with diabetes as a patient risk factor. Better control of the patient’s diabetic disease has been traditionally associated with better outcomes following surgery. This observation led to an initial effort reported by Furnary et al. [
Hyperglycemia has multiple immunosuppressive effects upon the host [
Delayed primary closure is a strategy for prevention of SSI if active infection or severe contamination is encountered at operation. Introduced in 1940 [
There is little evidence to support any specific methods for the prevention of SSI during the postoperative period. As has been emphasized, systemic antibiotics are not recommended nor are they proven to be of any value in the prevention of SSI. The current practices of using supplemental oxygen, core body temperature control, and glycemic control are extended into the postoperative period of time for several hours, but it is unclear whether the extension is the critical time or whether the intraoperative physiologic manipulation is the key period. The timing of use of these physiologic methods may be an important variable in the uncertainty that surrounds the benefit in using them.
Dressings are used on the wound following primary closure to avoid any potential secondary contamination from the environment. By 24 hours, the wound has a fibrin seal and at that time the primarily closed wound is not in need of dressings. In the uncommon event of a stoma being on the abdominal wall, a longer period of incisional coverage may be prudent. The reality is that infection of the surgical incision is the consequence of bacterial contamination during the procedure and secondary contamination afterwards is an uncommon occurrence.
Infection at the surgical site will continue to be a major challenge for prevention in elective colon surgery. The strong movement from the traditional open laparotomy for colectomy to greater utilization of laparoscopic-assisted techniques means that the surgical incision into the abdominal wall will be shorter and it is likely that infections may be less frequent and they may be less severe in the superficial and deep SSI categories. It is likely that organ/space infection following colonic resection and anastomosis will continue to be major sources of morbidity and mortality. Surveillance methods and definitions of SSI need to be standardized so that clinicians have a clear objectively based goal to pursue in the improvement of outcomes. Thus, there needs to be a continued use of all the accepted techniques for reduction of contamination at the surgical site and a continued vigilance in the prevention of local incisional conditions that promote infection.
New methods need to be advanced to reduce SSIs in colorectal surgery. It seems unlikely that great advances in systemic antibiotics will likely evolve to further improve outcomes. The efforts at achieving optimal physiological conditions in the host by answering the questions surrounding intraoperative supplemental oxygen, normothermia, and appropriate glucose control seem desirable. It seems appropriate that methods to prepare the colon itself prior to operation have the greatest opportunity to reduce intraoperative contamination and to potentially reduce anastomotic leaks. The area of colonic preparation needs innovative efforts in the development of effective methods for prevention and less recapitulation of studies that have limited value in advancing the outcomes of care.
The author participated in the Speakers Program for Merck and Co.; the author is a Consultant for IrriMax Corporation.