Improved Outcomes in Colon and Rectal Surgery part 8 doc

Despite significant evidence that bowel preparation before elective colorectal resection does not influence infectious com-plications and may actually increase the anastomotic leak rate

The specific type of fecal diversion, ileostomy versus colostomy,

does not influence anastomotic related outcomes.(25)

mechanical bOwel PRePaRatiOn

Mechanical bowel preparation before elective resection has been

surgical dogma since Halsted’s description of intestinal

anasto-mosis in 1887 Empiric-based practice relies on mechanical bowel

preparation together with oral antibiotics to reduce the bacterial

load of the bowel and, in theory, to decrease the risks of

anas-tomotic leak and surgical site infection Bowel preparation, far

from innocuous, is inconvenient and unpleasant for patients and

is associated with potentially harmful metabolic and fluid

distur-bances For these reasons, and because the purported benefits of

bowel preparation remain unproven, the utility of mechanical

preparation has been questioned

A Cochrane review evaluating the efficacy of bowel

prepara-tion in its ability to reduce postoperative complicaprepara-tions included

1,592 patients from nine randomized, controlled trials stratified

to a colectomy group and a low anterior resection group.(26) The

clinical leak rate in the colectomy group with and without bowel

preparation was 2.9% and 1.6%, respectively (p value not

signifi-cant) The clinical leak rate in the low anterior resection group

with and without bowel preparation was 9.8% and 7.5%,

respec-tively (p value not significant) When the surgical groups were

combined, the 6.2% clinical leak rate in the prepared group was

significantly higher than the 3.2% rate in the unprepared group

(p = 0.003) Meta-analysis of all other infectious complication

rates, including surgical site infection, demonstrated no

protec-tive effect of mechanical bowel preparation

Despite significant evidence that bowel preparation before

elective colorectal resection does not influence infectious

com-plications (and may actually increase the anastomotic leak rate)

surgical tradition and medico-legal pressure continue to

heav-ily influence the practice of colorectal surgery with respect to

mechanical bowel preparation

anastOmOtic techniqUe

Stapled techniques for low pelvic anastomosis have been

rigor-ously evaluated since their introduction into the armamentarium

of colorectal surgery A systematic Cochrane review comparing

the outcomes of straight, end-to-end stapled and handsewn

col-orectal anastomoses pooled data on 1,233 patients from nine

ran-domized, controlled trials.(27) This comprehensive meta-analysis

found no statistically significant difference with regard to clinical

leaks (stapled 6.3% vs handsewn 7.1%, p value not significant)

or radiologic anastomotic dehiscence (stapled 7.8% vs handsewn

7.2%, p value not significant).

A similarly conducted Cochrane review of four randomized,

controlled trials comparing stapled versus handsewn ileocolic

anastomoses during colon cancer resection demonstrated

signifi-cantly fewer clinical leaks in the stapled group (1%) compared to

the handsewn group (4.2%, p = 0.04).(28) Given the

fundamen-tal differences between ileocolic and colorecfundamen-tal anastomoses, it is

not surprising that they each may have unique technical

require-ments to reduce the risks of complications

In addition to evaluating the mechanics of forming the

anas-tomosis, the configuration of the anastomosis has been studied

with regard to possible reduction in the risk of leak Of the most common stapled colorectal anastomotic configurations (end-to-end, side-to-end Baker, colonic “J” pouch) there is no optimal configuration that consistently confers a risk reduction benefit (8, 10, 15, 17, 19, 29) It has also been shown that the size of the circular stapler does not contribute to the leak rate.(14)

Omental PeDicle

In an effort to quarantine an anastomosis in the event of a leak and

to mitigate the consequences of a leak, many surgeons utilize an omental pedicle To reach a pelvic anastomosis, the omentum is typically mobilized to survive off the left gastroepiploic artery The influence of an omental pedicle on anastomotic outcomes was eval-uated in a prospective, randomized study of 705 patients undergo-ing bowel anastomosis and no statistically significant influence on the rate or severity of leak was observed.(30) Another smaller, ran-domized, controlled trial of 126 patients demonstrated a protective effect of an omental pedicle; though, this study could be criticized for a rather high leak rate (22%) in the group of patients without

an omentoplasty.(31) Both of these studies reported overall leak rates including clinical and radiologic leaks

The discrepancy between these two trials is characteristic of many of the studies investigating anastomotic complications Leaks are low frequency events requiring large, homogenous study populations for accurate evaluation No firm evidence-based rec-ommendation can be made with regard to omentoplasty and its potential effects on colorectal anastomotic outcomes; bringing an omental pedicle to the pelvis should be done according to the surgeon’s preference

RaDiatiOn

Neoadjuvant radiotherapy has been evaluated in terms of poten-tially increasing the risk of dehiscence of pelvic anastomoses The proposed mechanism of increasing the leak rate is that pel-vic radiation may interfere with healing of the anastomosis due

to toxicity in the pelvis Radiation changes to the colon side of the anastomosis are usually not an issue as the irradiated colon

is resected at the time of the proctectomy to ensure that healthy colon is used to form the anastomosis

The Dutch Total Mesorectal Excision (TME) trial randomized 1,414 rectal cancer patients to neoadjuvant short-course radia-tion therapy followed by low anterior resecradia-tion versus resecradia-tion alone and demonstrated no significant difference between the two groups with respect to clinical anastomotic leak (neoadju-vant group leak rate 11% versus surgery alone leak rate 12%,

p value not significant) However, these results were difficult to

interpret because patients in the radiotherapy group were more likely to have a diverting stoma.(19, 22) The Swedish rectal can-cer trial randomized 1,168 patients to short-course neoadjuvant radiation followed by surgery versus surgery alone and also dem-onstrated no significant difference in leak rates between the two study arms.(32) A nonrandomized study comparing 150 patients who received long-course chemoradiation (5,040 cGy) followed

by surgery to 531 patients who underwent surgery alone dem-onstrated similar results with 4% overall leak rate in each group

(p = 0.86).(10) The notion that neoadjuvant radiotherapy

increases the risk of leak is not supported by the majority of the

literature and may be incorrectly based on the fact that low pelvic

anastomoses in the setting of total mesorectal excision are more

likely to leak.(33, 34)

Pelvic DRains

Pelvic drains are placed by some surgeons to prevent colorectal

anastomotic leaks and to diagnose leaks sooner with the hope of

initiating treatment before leaking patients clinically

decompen-sate The possible mechanism whereby pelvic drains,

theoreti-cally, may protect against colorectal anastomotic leak relies on the

characteristics of the extra-peritoneal low pelvis in that the

peri-toneum is absent Violation of the presacral space during

proctec-tomy leaves a significant raw surface and without the absorptive

abilities of the peritoneum fluid can collect in the dependent dead

space created by total excision of the mesorectum Further

com-plicating the matter is the potential for negative pressure in the

low pelvis that promotes the accumulation of fluid that can

possi-bly disrupt the anastomosis A pelvic drain can, possipossi-bly, prevent

accumulation of fluid behind the anastomosis These theoretical

benefits of pelvic drainage together with results of statistically

under-powered trials may explain why many surgeons continue

to drain pelvic anastomoses

Routine pelvic drainage has been evaluated in retrospective

fashion as well as with randomized, controlled trials with regard

to a possible influence on the occurrence and diagnosis of

col-orectal anastomotic leak For example, the data collected in the

prospective, randomized Dutch TME trial was studied

after-the-fact in retrospective fashion to determine the utility of pelvic

drainage during low anterior resection.(19) Patients in this trial

were randomly assigned whether or not to receive neoadjuvant

radiation therapy before TME At the time of operation,

place-ment of pelvic drains was decided at the discretion of the

oper-ating surgeon Multiple regression analysis demonstrated that

pelvic drainage was strongly associated with a lower clinical leak

rate (leaks occurred in 9.6% of patients with drains compared

with 23.5% of patients without drains, p < 0.001) Moreover, the

need for re-operation in leaking patients was significantly more

likely in patients without preexisting pelvic drainage (97% of

leaking patients without drains were re-operated versus 74% of

leaking patients with drains, p = 0.006) Other reviews and

ran-domized trials regarding the use of drains have been published

with contradicting results and conclusions; some attributed an

increase in the leak rate to pelvic drainage.(14, 29, 35, 36) Like

the retrospective study reviewed above, many of these papers may

not have accurately evaluated the utility of drains due to lack of

statistical power or suboptimal methodology

To better evaluate the utility of pelvic drainage after

colorec-tal anastomosis, a Cochrane review tested the hypothesis that

anastomotic drainage after elective colorectal surgery does not

prevent the development of complications.(37) This

exhaus-tive meta-analysis pooled data on 1,140 patients from six

ran-domized, controlled trials The clinical anastomotic leak rate

for patients with drains versus without drains was 2% and 1%,

respectively (p value not significant) Stratification of the data

according to the height of the anastomosis also showed no

ben-efit of drainage even for low pelvic anastomoses In addition,

the re-operation rates between patient groups with and without

drains were comparable This review does not support the prac-tice of routinely draining colorectal anastomoses

The practice of routinely draining colorectal anastomoses is not supported by strong scientific evidence In addition, there is

no compelling literature supporting the notion that pelvic drains facilitate earlier diagnosis of a leak

miscellaneOUs

Other factors shown to increase the colorectal anastomotic leak rate include total mesorectal excision (8, 15, 16), height of the anastomosis from the anal verge (5, 20, 33), male gender (5, 20), and prolonged operating time (20) Each of these factors is either difficult or impossible to influence Due to the large numbers

of patients required to study anastomotic complications, many variables may never be studied sufficiently in terms of possibly contributing to anastomotic leak (Table 7.1)

Total mesorectal excision, as it was originally described, left a relatively ischemic distal rectum after resection for proximal rec-tal cancer Tumor specific mesorecrec-tal excision for proximal recrec-tal cancer has become popular as it preserves the distal mesorectum without compromising oncologic adequacy and decreases the risk of leak compared with total mesorectal excision.(10, 15, 33, 38) The height of an anastomosis can influence tension across the tissues and, together with prolonged operating time, is likely

a surrogate marker for more difficult operations especially in the narrow, male pelvis It is also postulated that, in low pelvic anas-tomoses, the proximate anal sphincter increases the intraluminal pressure across the anastomosis jeopardizing its integrity

In terms of the surgical approach, the Clinical Outcomes of Surgical Therapy (COST) trial and others have not demonstrated

an increased anastomotic failure rate with regard to laparoscopic versus conventional open colectomy.(39–41) Trials evaluating laparoscopic versus open rectal cancer resection with colorectal anastomosis are underway

clinical PResentatiOn

The clinical manifestations of anastomotic dehiscence vary depending on the location of the leaking anastomosis, the severity of the leak and whether or not the leak is contained or walled-off For these reasons, while many patients with anasto-motic dehiscence present acutely with signs and symptoms of sepsis and an abdominal catastrophe, a subset of patients have

Table 7.1 Factors with conflicting evidence in the literature that

may or may not impact anastomotic leak rates

Smoking or alcohol abuse (33, 46, 59) Obesity (8)

Hospital operative caseload (24) Surgeon subspecialty training and volume (33, 60, 61) Diabetes (48)

Cardiovascular disease (48) Steroid use (46, 48) Malnutrition (46, 62) Anemia (48) Blood transfusions (46) Intraoperative rectal irrigation ASA score (33)

Field contamination

a more sub-acute, insidious presentation This is more typical

of walled-off infections and leaks that have sealed on their own

Possibly contributing to a sub-acute presentation of a leak is the

use of antibiotics during recovery from colorectal surgery (for

pneumonia, urinary tract infection, etc.) that can mask the signs

and symptoms of an occult leak While the majority of patients

with colorectal anastomotic leak are diagnosed within a week of

operation, a significant proportion of patients are diagnosed well

beyond this timeframe (Table 7.2) Patients with a more delayed

presentation of a leak have often been released from the hospital

only to be diagnosed upon re-admission.(42)

Patients with feculent peritonitis or diffuse purulent peritonitis

typically become acutely ill, often in dramatic fashion, with classic

signs and symptoms of peritonitis, hemodynamic instability and

rapid progression to multisystem organ dysfunction Meanwhile,

in a considerable number of patients, recognition of an

anasto-motic leak may be difficult due to the significant overlap between

the signs and symptoms of a leaking patient and those of a

typi-cal patient recovering from major abdominal surgery Patients

may present with any combination of fever, tachycardia, varying

degrees of abdominal pain and distension, ileus, diarrhea,

mal-aise, failure to thrive, bowel obstruction, and septic shock Some

patients present with symptoms mimicking cardiac complications

such as respiratory failure and chest pain Leaking patients may

also fail to clinically progress or recover within a usual timeframe,

have increasing narcotic demands, or have decreased urine output

requiring fluid boluses The physical exam of a leaking patient may

include focal or diffuse abdominal tenderness, rigidity, guarding,

abdominal distension, and evidence of varying degrees of

hemo-dynamic collapse Patients may have leukocytosis, typically with a

left shift, leukopenia, metabolic acidosis, or thrombocytopenia

After any intestinal anastomosis, the surgeon must maintain a

high index of suspicion when evaluating patients with unusual

signs of sepsis or patients who fail to meet the clinical milestones

of normal recovery within a typical timeframe The potential for

delay in diagnosis is significant; delays may impact patient

out-comes and have medicolegal ramifications

DiagnOsis

Patients with generalized peritonitis consistent with a leak require

urgent return to the operating room with concomitant

intrave-nous fluid resuscitation and broad-spectrum antibiotics In this

setting, the time to re-operation is critical and a diagnostic jour-ney with imaging studies will only delay potentially life-saving abdominal exploration Meanwhile, patients with a more subtle clinical presentation do not mandate immediate exploration and may benefit from imaging studies to confirm the diagnosis and direct appropriate management

Although no single radiologic study is ideal for investigating a possible leak, computed tomography (CT) and contrast enemas are the tests of choice in this setting The advantage of triple con-trast CT scanning with intravenous, oral, and rectal concon-trast is that it may identify other potential underlying pathologies like ileus, abscess, hematoma, and bowel obstruction CT scan find-ings consistent with anastomotic leak include extravasation of luminal contrast, perianastomotic fluid, ascites, and varying amounts of extra-luminal gas With the exception of contrast extravasation, many of the CT findings in leaking patients are not specific and overlap considerably with CT scans of nonleaking patients in the postoperative setting The mere presence of free air

in the postoperative period is not specific for a leak and has been demonstrated by CT in control patients without anastomoses up

to 9 days after operation and even later.(43, 44) Depending on the clinical circumstances, inconclusive CT findings can be followed

up with a contrast enema study, repeat CT or abdominal explora-tion to exclude anastomotic leak

According to some of the literature, CT may be superior to contrast enema when determining the integrity of an anastomo-sis.(42) Potential shortcomings of enema studies in this setting are that the water-soluble contrast can dilute out and compro-mise resolution of a contrast enema and that clinicians may be reluctant, in the early postoperative period, to introduce a suf-ficient column of enema contrast to adequately fill the rectum

On the other hand, some of the retrospective literature strongly favors contrast enema over CT in terms of diagnosing a pelvic anastomotic leak outright as well as after a CT scan fails to dem-onstrate a leak.(9, 45) Extravasation or pooling of rectal contrast outside of the bowel lumen during an enema study is pathogno-monic of leak (Figures 7.1 and 7.2) Water-soluble contrast must

be used when evaluating for a possible anastomotic dehiscence as extravasated barium increases the severity of a leak by adding to the inflammatory response in the abdomen In reality, the choice

of imaging study in a particular patient is influenced by the clini-cal presentation, institutional expertise, and available resources

management

The management of anastomotic dehiscence in a particular patient depends on the clinical manifestations of the leak and the condition of the patient (Figure 7.3) Common manifesta-tions of a leak from a colorectal anastomosis are asymptomatic, leak without abscess, leak with associated abscess, peritonitis, and colocutaneous fistula

Asymptomatic

Early in the experience with circular staplers, routine water- soluble contrast enemas demonstrated that as many as half of patients with pelvic anastomoses demonstrated a radiologic leak during the first postoperative week Often these are short, sim-ple sinus tracts originating from the anastomosis In otherwise

Table 7.2 The time interval between colorectal anastomosis and

diagnosis of a leak

Post Op Day

a Mean.

b Median.

treatment period of several days is reasonable after which par-enteral nutrition or re-operation often need to be addressed Clearly, failure to improve or clinical deterioration requires sur-gical intervention It is difficult to predict which patients will suc-cessfully recover without re-operation in the setting of a leak; this treatment pathway requires dedicated attention on the part of the surgeon with frequent hands-on re-evaluation

Leak with associated abscess

Stable patients with CT evidence of a contained leak with an abdominopelvic abscess should, initially, be treated with drainage and appropriate antibiotic therapy (Figures 7.4 and 7.5) Drainage

Figure 7.1 Gastrografin enema demonstrating anastomotic leak (black arrows)

from colorectal anastomosis (anterior-posterior view).

Figure 7.2 Gastrografin enema demonstrating leak with contained abscess (white

arrows) from colorectal anastomosis (lateral view).

No abscess

No peritonitis

Antibiotics Bowel rest

No resolution or Patient worsens

Anastomotic Leak

Laparotomy

Antibiotics

Resuscitation

Address any collections DrainageAntibiotics

Leak resolves

Laparotomy

No further treatment

Worsens Fistula

Antibiotics Bowel rest Nutrition

No resolution Resolution

No further treatment

Figure 7.3 Management algorithm for patients with anastomotic leak.

asymptomatic patients with an anastomotic leak discovered

inci-dentally, no intervention is required as the leak is not likely of

clinical consequence and will seal spontaneously

Leak without abscess

Stable patients with mild symptoms, focal abdominal tenderness,

and radiologic evidence of anastomotic leak without abscess may

be initially treated nonoperatively with bowel rest and

intrave-nous fluids and broad-spectrum antibiotics These are often

minor leaks that can, potentially, seal spontaneously The

dura-tion of treatment is empiric and is based on the clinical response,

the patient’s condition, and the surgeon’s judgment An initial

is usually performed percutaneously or trans-anally through the

anastomotic defect There are situations where operative

drain-age is required due to inaccessibility of an abscess by less invasive

routes, but these are quite uncommon As before, patients who

fail nonoperative treatment require exploration A contained leak

can rupture freely into the abdomen; depending on the clinical

circumstances, repeat imaging, or urgent exploration would be

required in this situation

Peritonitis

Patients with generalized peritonitis consistent with a leak require

urgent exploration with aggressive fluid resuscitation and

intrave-nous antibiotic administration on the way to the operating room

Typically, these patients decompensate quickly and become unstable

and must be treated in urgent fashion As reviewed earlier, in these

situations, there is no benefit to pursuing diagnostic studies as the

consequences of delaying operative intervention may be dire

Colocutaneous fistula

Fistulization to the skin, typically through a drain site or skin

incision, may be a late manifestation of anastomotic leak Once

a fistula is observed clinically, a CT scan is helpful to evaluate for

any undrained collection which would need to be addressed In

general, once the local sepsis has been controlled, most

anasto-motic fistulae will close with bowel rest Optimizing nutritional

status and attention to wound care are important in these patients

Specific circumstances that may preclude spontaneous resolution

of a fistula are distal obstruction, associated anastomotic

stric-ture, radiation, and steroid therapy Patients who fail

nonopera-tive treatment may benefit from operanonopera-tive intervention

OPeRative inteRventiOn

The goals of re-operation for anastomotic leak are to control the

source of sepsis, remove any purulence or contamination and

prevent ongoing leak While preservation of function is

impor-tant, it must be emphasized that these are life-saving operations

There are a number of options available to the surgeon returning

a patient to the operating room to address a leaking anastomosis and the particular procedure performed is decided at the time of exploration based on clinical judgment and the unique presenta-tion of the patient on the table

As most patients undergoing reoperation for suspected leak require some form of fecal diversion that may be permanent, potential sites for stoma formation should be marked preopera-tively In the operating room, it is helpful to have the patient in either split leg position or in lithotomy stirrups to facilitate access

in case proctoscopy is required In terms of the surgical approach

to re-operation in the setting of a leak, the quickest approach is likely conventional laparotomy Laparoscopic exploration has potential benefits, especially if the original operation was per-formed laparoscopically or if the diagnosis of anastomotic leak

is not clear, but a minimal-access approach to anastomotic leak should only be performed by surgeons with expertise in advanced laparoscopic techniques Microbial cultures of the peritoneal fluid encountered during re-operation for anastomotic leak most often demonstrate polymicrobial flora and are of questionable benefit in terms of directing patient management.(23)

Resection of the leaking anastomosis and colostomy creation

Traditionally, the surgical approach for a colorectal anastomotic leak has been to dismantle the anastomosis, bring out the colon

as an end stoma, close the rectum as a Hartmann pouch, washout the abdomen, and place drains.(12) This modified Hartmann procedure is very effective at removing the septic source and alleviating the abdominal sepsis A major drawback of this oper-ation is that end colostomy reversal is technically challenging and carries its own risk of morbidity It is not surprising that these end colostomies become permanent in a substantial pro-portion of patients.(4, 23, 46) Exteriorization of the rectal stump

as a mucus fistula (typically described in staged resections for fulminant proctocolitis) can be considered in the rare circum-stance of a difficult to control rectum.(47)

Figure 7.4 Abdominal CT scan demonstrating a large abdominal abscess (arrows

mark cavity).

Figure 7.5 CT scan of a percutaneous drain in an abscess.

Leaving the leaking anastomosis in place

An alternative to end stoma creation in many instances consists of

abdominal washout, proximal fecal diversion via loop stoma, and

drainage of the anastomotic leak.(19, 23, 45, 46) The benefits of this

approach are that it effectively controls the septic source and allows

the majority of patients to undergo stoma reversal in the future.(4,

6, 17) The main criticism of leaving a leaking anastomosis in place is

that luminal contents proximal to the anastomosis may provide an

ongoing source of contamination and that the anastomosis may

stric-ture or fistulize.(23) Review of the literastric-ture does not substantiate the

concern of ongoing contamination and demonstrates that proximal

diversion is safe and has a high rate of anastomotic salvage

The use of a colostomy versus ileostomy for diversion does not

impact anastomotic outcomes but meta-analysis of 1,204 patients

demonstrated significantly fewer stoma related complications and

postreversal hernias with loop ileostomy.(25) Some advocate lavage

of the proximal colon to eliminate whatever stool is proximal to the

anastomosis and some surgeons describe suturing closed the

anas-tomotic defect in an effort to contain the leak; the utility of these

maneuvers remains empiric Deciding whether or not to resect or

preserve a leaking anastomosis depends on the surgeon’s experience,

the size of the anastomotic defect, and the viability of the colon

Repeat anastomosis after resection of the leaking anastomosis

In certain situations, it may be possible to resect a leaking

anasto-mosis and perform a new anastoanasto-mosis with or without proximal

diversion This may be technically possible when dealing with a

leak from an ileocolic anastomosis Colorectal anastomoses are

unlikely to be amenable to immediate reconstruction given the

limitations of reach, especially in a hostile abdomen

Exteriorization of the leaking anastomosis

Another surgical option for treating a patient with anastomotic

dehiscence is to exteriorize the leaking anastomosis as a stoma This

removes the septic source from the abdomen and may be performed

rapidly The potential problems with this damage control approach

are that the anastomosis rarely can reach out to allow

exterioriza-tion and that even if the leaking segment can reach out, it will make

for a very bulky and difficult to manage stoma In addition, this

form of stoma may be fraught with wound-related complications

The utility and practicality of this approach are questionable

shORt anD lOng-teRm imPlicatiOns Of leak

The short-term consequences of an anastomotic leak requiring

operative intervention are substantial The 30-day mortality rate

associated with anastomotic leak is typically documented in the

10% to 15% range and has been reported to be as high as 36% (3, 5,

42, 46, 47) Indeed, the most common cause of death after

colorec-tal cancer resection is due to anastomotic leak.(4) In comparison to

patients who recover uneventfully, patients who suffer anastomotic

leak consume significantly more healthcare resources After

re-operation for leak, roughly 50% of patients require intensive care

and a number of patients go on to require additional percutaneous

drainage procedures or operations.(4, 17) Also, the average length

of stay of patients with anastomotic leak is considerably prolonged

compared with patients who recover normally from colorectal

resection.(3, 48) In terms of overall morbidity rates, patients who

experience an anastomotic leak are much more likely to experience

further complications than patients who did not leak.(47) It is for

these reasons that anastomotic leak is the most dreaded complica-tion of colorectal surgery

Anastomotic leak also carries significant long-term conse-quences The quality of life of patients with permanent fecal diver-sion after a leak and bowel function after experiencing a leak are significantly impaired.(49) In comparison with patients who did not leak, patients who undergo stoma reversal after resolution of a leak have decreased rectal capacity and compliance and more diffi-culties evacuating.(7) In addition, in a review of nearly 1,400 surgi-cal patients treated for rectal cancer, patients who leaked were less likely to receive adjuvant chemotherapy and when they did receive chemotherapy, it was more likely after a substantial delay.(6)

In a multicenter Scottish study of 2,235 patients who under-went curative resection for colorectal cancer, the 5-year overall survival rate, excluding mortalities within 30-days of operation, for patients who leaked compared with patients who did not

leak was 42% and 55%, respectively (p < 0.01) (3) The 5-year

cancer-specific survival rate, also excluding postoperative deaths, for patients who leaked compared with patients who did not leak

was 50% and 68%, respectively (p < 0.001) The increased risk of

cancer-specific death in patients with an anastomotic leak was most apparent between 2 and 4 years after surgery Similarly, other studies have demonstrated increased local recurrence rates (5) as well as decreased overall and cancer-specific survival (50) after anastomotic leak The etiology of these inferior long-term outcomes in patients who suffer a leak remains speculative

anastOmOtic stRictURe

Colorectal anastomotic stricture may occur in up to 10% of patients depending on how a stricture is defined.(51, 52) From a clinical standpoint, stricture may be defined as a symptomatic narrowing

of the anastomosis that obstructs the flow of intestinal contents (53) Alternatively, a stricture may be defined by the inability to pass

a particular size of proctoscope through an anastomotic narrow-ing The vast majority of anastomotic strictures tend to be short segment stenoses less than a centimeter in length (Figure 7.6)

Figure 7.6 Contrast enema demonstrating colorectal anastomotic stricture.

Figure 7.7 (A) Colonoscopic view of a strictured colorectal anastomosis (B) Passage of a through-the-scope balloon dilator (C) Hydrostatic dilation of the stricture

(D) The dilated anastomosis.

Factors predisposing to anastomotic stricture include

anasto-motic leak, postoperative pelvic infection, and proximal diversion

In addition, two meta-analyses concluded that stapling the

col-orectal anastomosis increases the risk of stricture formation

com-pared with hand sewing the anastomosis.(27, 54) It is hypothesized

that strictures develop due to an inflammatory response or,

possi-bly, from mucosal gaps within a staple line that heal by secondary

intention Although ischemia is commonly included as a

poten-tial etiology of stricture formation, the pathophysiology remains

speculative Whether or not a smaller diameter circular stapler

increases the risk of stricture formation is not clear; nonetheless,

the convention remains to use the largest diameter stapler that the

bowel can accommodate Late anastomotic stricture formation is

associated with recurrent cancer, inflammatory bowel disease, and

radiation injury and must be thoroughly investigated

DiagnOsis anD tReatment

While most strictures are likely incidental findings, certain patients have symptoms such as mechanical obstruction or impaction at the level of the stricture, constipation, tenesmus, frequent bowel movements, or diarrhea In general, asymptomatic strictures in patients with intestinal continuity are not clinically relevant and

do not require treatment Meanwhile, symptomatic patients and asymptomatic patients undergoing evaluation before reversal of

a diverting stoma who demonstrate stenosis require intervention Stoma reversal in the face of a stricture risks anastomotic disrup-tion at the site of the stoma takedown and should be avoided The majority of colorectal anastomotic strictures that require intervention are readily salvaged using endoluminal dilating techniques.(55) Typically, dilation is postponed until the anas-tomosis has healed and become more pliable; waiting over 4–6

weeks is prudent Simple methods used to dilate a low

anastomo-sis include gentle digital rectal exam or sequentially sized dilators

(i.e., bougie, Hegar, etc.)

Strictures out of reach for these modalities or that require

con-trolled dilation under direct observation are usually treated with

commercially available through-the-scope (TTS) hydrostatic

bal-loon dilators that control radial expansion using a pressure gauge

(Figure 7.7) Sequential dilation to a diameter >20 mm is usually

accomplished under conscious sedation with or without empiric

antibiotic coverage and has a low complication rate.(56) Balloon

dilation is successful in the majority of cases although repeat

dila-tions may be required Injecting triamcinolone, a long-acting

corticosteroid, into the stricture or releasing the stricture using

electrocautery or laser in combination with balloon dilation may

decrease the need for repeat dilations without significantly

increas-ing the complication rate.(57) Larger diameter, over-the-wire

bal-loons may require fewer repeat dilations than TTS devices.(55)

The few patients with short anastomotic strictures who do not

respond to repeated dilation and patients with long, irregular

strictures may be candidates for resection with repeat

anasto-mosis Depending on the height of the stricture, the anastomosis

can be resected and intestinal continuity may be restored with

either colorectal or coloanal anastomosis To avoid dissecting out

the distal rectum in a reoperative pelvis consideration could be

given to resecting the anastomosis and reconstructing with rectal

mucosectomy and a pull-through operation.(51, 53)

Alternatives to resection to correct an anastomotic stricture

include a number of creative stricturoplasty techniques using

tran-sanal endoscopic microsurgery, conventional staplers, or a special

mechanical anastomotic staple cutting device.(58) Individual cases

of endorectal stenting have been reported in the literature but the

utility and long-term outcomes of stenting in the setting of a benign

stricture remain questionable and require further evaluation

cOnclUsiOn

Anastomotic complications are difficult to predict and carry

sig-nificant risks of morbidity and mortality Attention to detail while

forming a colorectal anastomosis is paramount to reducing the

risk of complications Tissue sealants, novel compression

anasto-mosis devices, anastomotic buttressing materials, and alternatives

to conventional fecal diversion may each contribute to reducing

anastomotic complications in the future

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Scott R Steele and Clifford L Simmang

Financial Disclosure: No outside financial support or provision

of supplies was solicited or received in connection with this work

Disclosure and Proprietary Statement: This is an original work

by the above author The opinions expressed are the author’s and

author’s alone They do not necessarily reflect the opinion of the

U.S Government, the U.S Department of Defense, or Madigan

Army Medical Center

challenGinG case

A 72-year-old female is scheduled to undergo a low anterior

resection for T3N0M0 rectal cancer She has been confined to a

wheelchair for the last month due to a fibular fracture Her

co-morbidities include diabetes, hypertension, hyperlipidemia, and

she has a 50 pack-year smoking history Describe the optimal

management for deep venous thrombosis prophylaxis

case manaGement

The patient falls into a high risk classification as evidenced by

her older age, recent immobility, smoking history,

comorbidi-ties, malignancy, and need for pelvic surgery In addition to the

mechanical measures (e.g., graduated compression stockings or

intermittent pneumatic compression devices and early

ambula-tion) this patient should receive either subcutaneous

unfraction-ated heparin (typically 5,000 IU two or three times per day) or

low molecular weight heparin (~0.5 IU/kg), with higher doses

reserved for those patients within the most at risk group The first

dose of unfractionated subcutaneous heparin should be given

before induction, preferably 1–2 hours before incision, as some

evidence indicates that venous thrombotic events occur more

commonly during the time of anesthesia induction Perioperative

use should continue until the patient is fully ambulatory This

may require patient education on self-injection to continue after

discharge, for up to 10–14 days

introduction

Despite ever-evolving advancements aimed at improving surgical

outcomes, which have included technological innovations,

compre-hension of perioperative physiology, and implementation of

clini-cal pathways, postoperative complications continue to account for

significant health care costs Highlighting this, in a study evaluating

the financial impact on surgical site infections alone, development

of one single preventable surgical site infection was associated with

an increased length of stay of almost 11 days, at a resultant cost of

$27,000 for each patient.(1) In addition, lost work days, delayed

functional recovery, and resultant physical deficits are oftentimes

not as easily quantifiable in monetary amounts, yet create an even

larger impact on both patient and society alike Thus, emphasis

needs to be placed not only on the identification and treatment of

these complications, but also prevention as a major focus in order

to optimize outcomes In this chapter we will review the current status of a variety of perioperative parameters surrounding com-plications encountered with colon and rectal surgery as well as explore the most recent measures employed for prevention More detailed treatment options are found in specific chapters elsewhere within this text

pain

Although it may seem intuitive that adequate control of postop-erative pain is a mandatory and rather easy standard to achieve,

in practice this oftentimes remains a far more difficult objective

to attain In part, this may be secondary to the lack of having an accurate way to predict those patients that will have difficulty with postoperative pain control In addition, we frequently use primi-tive measures to quantify pain, relying heavily on devices such as visual analogue scales and verbal pain scales commonly employed

in the recovery phase, which, due to language and cultural barri-ers, often do not have adequate correlation amongst patients This

is especially evident when trying to accurately detect and record changes in pain level over time, evaluate which pain dimension the patient is being asked to report (i.e., intensity versus relief), or

to which interval does the pain level correspond (i.e., current level versus average over a time period).(2) Despite these difficulties, adequate pain control remains such an important component to the overall care of the postoperative patient, it is often referred to

as the fifth vital sign Optimal control of pain continues to be pur-sued through a multifactorial and multifaceted approach

Emphasis in recent years has been toward adequate preoperative and thus preemptive pain control Medications such as ketorolac, COX-2 inhibitors, and local anesthesia before the incision have all been used in attempt to lessen postoperative pain, as well as decrease reliance on more traditional methods such as narcotics Sim and colleagues in a prospective randomized blinded study of 40 patients undergoing elective colorectal surgery found the perioperative use

of COX-2 inhibitors, which included a single dose 1 hour before surgery, was associated with a significant decrease in both postop-erative narcotic use as well as shorter recovery of bowel function and earlier discharge.(3) Lack of widespread use of these agents has,

in part, been centered on surgeon concerns regarding the potential for increased bleeding felt to be associated with use of these medica-tions Yet this appears to be unfounded As narcotics are plagued by side effects such as respiratory depression, constipation, and ileus, which hinder gastrointestinal recovery following colorectal sur-gery, methods to decrease their usage seem beneficial in this patient population This is not to say that patients following both colorectal and anal surgery do not require narcotics; However, other classes

of medications may improve pain control, while minimizing the dependency on them Other Nonsteroidal Antiinflammatory Drugs (NSAIDS) have also been evaluated in the postoperative period as independent pain-controlling agents, yet appear to work better in