- Email: [email protected]
Early postoperative intestinal obstruction
COMPLICATIONS IN SURGERY
Early Postoperative Intestinal Obstruction THE CASE A 42-year-old, otherwise healthy, male patient underwent an operation for acute appendicitis through a transverse, musclesplitting, right lower quadrant incision. A perforated appendix was resected, and a small quantity of localized pus was sucked out. The wound was closed in layers, including the skin, and no drain was left in situ. Wide spectrum antibiotics, which were started before the operation, were continued postoperatively. Nasogastric tube was removed at the end of the procedure. Intramuscular opiate-analgesia was prescribed. On postoperative day 1: The patient was afebrile and ambulating. His abdomen was minimally distended and tender around the incision site. Auscultation revealed “a few bowel sounds.” Oral clear fluids were ordered. On postoperative day 2: The patient reported that he passed flatus. Soft diet was ordered. At night, the patient vomited a large quantity of bile-containing gastric contents. The Intern on call inserted a nasogastric tube. On postoperative day 3: The patient is afebrile, and his abdomen is soft, non-tender, and minimally distended. His bowel sounds are judged as “active.” Nasogastric output during the 8 hours since insertion was 700 ml of deeply green-stained fluid. White blood cell count was 10,500; levels of serum urea and electrolytes are normal. Plain abdominal radiograph reveals free intra-abdominal air and marked dilatation of the small bowel with air-fluid levels. The colon is not dilated and contained some air. What Is Your Diagnosis? 1. 2. 3. 4. 5. 6.
“Early” adhesive mechanical small bowel obstruction Paralytic ileus “Early” adhesive large bowel obstruction Acute stress gastritis Excessive aerophagia Both A and B are possible
What Would You Do Now? 1. 2. 3. 4. 5. 6.
Order a computed tomography (CT) scan of the abdomen Change the antibiotics Order a small bowel series with barium Order small bowel series with gastrografin Perform a diagnostic laparoscopy None of the above
See correct answers on page X. Correspondence: Inquiries to Moshe Schein, MD, Department of Surgery, Bronx Lebanon Hospital Center, 1650 Selwyn Avenue, 4th Floor, Suite 4F, Bronx, NY 10457; (718) 960-1312; e-mail: [email protected]
MOSHE SCHEIN, MD Department of Surgery Bronx Lebanon Hospital Center Bronx, New York
THE DISCUSSION OF THE CASE Early postoperative small bowel obstruction (EPSBO)—the “early” referring usually to the first 30 postoperative days— has long been recognized as a distinct clinical entity that is often difficult to differentiate from postoperative ileus. The pathophysiology, diagnosis, and management of EPSBO differ in several respects from that of small bowel obstruction occurring in a patient with virgin abdomen (no prior intraperitoneal surgery) or that of adhesive obstruction at a time remote from the operation. Although adhesions account for most small bowel obstructions in the early postoperative period, several other factors, including technical problems at the time of operation and internal herniation through mesenteric defects, have to be considered. The definition of EPSBO has varied from clinical diagnosis alone, to symptoms and signs along with radiographic evidence, to operation— confirmed obstruction, causing further difficulties in estimating the true incidence and in development of a rational treatment plan. Definition and Incidence of EPSBO To reliably define EPSBO, it is essential to differentiate it from postoperative ileus. All postoperative patients experience ileus for a variable period that depends on several factors: the magnitude of surgery, general condition of the patient (eg, malnutrition may cause severe hypoalbuminemia, which in turns results in swelling of the bowel), associated electrolyte abnormalities, and the occurrence of complications like postoperative pneumonia or urinary tract infection. Small bowel is the first to recover peristaltic activity a few hours after the operation, followed by the stomach in 8 to 48 hours; the colon remains inactive for 48 to 72 hours and is the last organ to recover.1 The differentiation becomes more difficult because of the incisional pain and the frequent administration of analgesics, which posses their own paralytic activity on the large bowel. Stewart et al defined EPSBO as temporary return of bowel function followed by distension and obstipation occurring within 4 weeks of laparotomy and subsequent confirmation of obstruction at re-operation.2 Using this definition, they reported an incidence of 0.69% in a prospective study of 8098 patients. Sykes and Schofield also utilized a similar definition: a complete mechanical small bowel obstruction occurring post-
CURRENT SURGERY • © 2002 by the Association of Program Directors in Surgery Published by Elsevier Science Inc.
0149-7944/02/$22.00 PII S0149-7944(02)00625-6
289
operatively (during the same admission), with subsequent confirmation at re-laparotomy or autopsy.3 Pickleman and Lee, on the other hand, relied on symptoms and signs of obstruction for 7 days or longer at any time within the 30-day period or symptoms and signs of obstruction occurring from 7 to 30 days after the operation, lasting any number of days.4 Quatromoni et al utilized abdominal x-rays in addition to clinical signs and symptoms of small bowel obstruction, again occurring within 30 days of operation.5 Similarly, Frykberg and Phillips considered EPSBO to be present when at least 1 of the 4 standard clinical features of bowel obstruction (abdominal pain, vomiting, distension, and obstipation) were present along with radiographic confirmation, as interpreted by a radiologist.6 In another prospective study, Ellozy et al showed that EPSBO occurred in 9.5% of patients.7 In this study, EPSBO was considered present when crampy abdominal pain, vomiting, and radiographic findings consistent with intestinal obstruction were present after an initial return of bowel function within 30 days after surgery. In a retrospective review of 1475 patients after abdominal aortic surgery, Siporin et al showed the incidence of EPSBO to be 2.9%.8 It is likely that the definition used by Stewart et al2 underestimates the problem by excluding the cases that resolve spontaneously, and most authors have utilized a definition similar to the one used by Ellozy et al.7
Inflammatory causes. A local inflammatory process, such as an intra-abdominal abscess, may lead to EPSBO by causing small bowel adherence to the abscess wall. These septic adhesions were responsible for EPSBO in 8% and 4% of cases reported in 2 series.4,6 In another series, intra-peritoneal abscess were present in 12 of 26 cases of EPSBO.3 Other rare causes of EPSBO include intussusception and intramural intestinal hematoma.4,6 Table 1 summarizes the various origins of EPSBO.
Pathophysiology and Causes of EPSBO
The Risk of EPSBO According to the Procedure
Adhesions. Most cases of EPSBO resolve with nonoperative treatment, and it is likely that adhesions are the causative factor. Also, in patients that require surgery, the usual cause of obstruction is adhesions—the cause of EPSBO in 91%4 and 92%2 of patients. Adhesion formation follows any operative peritoneal injury or that caused by peritoneal contamination and infection. This leads to an inflammatory response with activation of complement and coagulation cascades along with exudation of fibrinogen-rich fluid. Thrombin converts fibrinogen to fibrin, which attaches the adjoining damaged surfaces. At this stage, if fibrin is not degraded, fibroblasts propagate in this matrix and collagen deposition occurs, leading to the conversion of fibrinous adhesions to fibrous adhesions. If fibrin degradation is complete, fibrinous adhesions resolve and mesothelial regeneration becomes complete. However, peritoneal injury-surgery or peritonitis has been shown to depress fibrinolytic activity. This early balance between fibrin formation and its degradation in the peritoneal cavity during and after surgery seems to be the major determinant of postoperative adhesion formation.9 –12 Internal herniation. Any defect within the peritoneal cavity has the potential to cause EPSBO by internal herniation. When a mesenteric or omental defect is created, or an opening is left in the “gutters”— behind a colostomy or enterostomy— small bowel may herniate through, leading to EPSBO. In one series, herniation through a pelvic floor defect after abdomino290
TABLE 1. Causes of EPSBO Adhesions Internal herniation Volvulus Fascial dehiscence Abdominal wall sutures Intra-abdominal abscess Intra-abdominal hematoma Obstruction caused by preexisting disease Intussusception Missed pathology (eg, another small bowel bezoar). EPSBO ⫽ early postoperative small bowel obstruction.
perineal resection was reported to be responsible for 5 out of 13 cases of EPSBO.13
The risk of EPSBO seems to vary depending on the type of the precipitating surgical procedure. Operations in the supra-colic compartment (eg, open cholecystectomy) have lower risk compared with operations in the infra-colic compartment.4,5 According to Stewart et al, the operations most frequently associated with EPSBO were groin hernia operations associated with small bowel obstruction, operations on the left side of the colon and rectum, and small bowel operations.2,13 Hepatobiliary operations had the lowest risk. After appendectomy, increased risk of EPSBO was observed for perforated appendicitis but not for nonperforated appendicitis.2 In the series reported by Fryckberg and Phillips, colon was the organ most commonly operated upon initially and 77% of the procedures were emergencies; 11 out of 26 cases were for trauma.6 In Pickleman and Lee’s experience, colectomy, exploratory laparotomy, and enterectomy constituted high-risk operations for the development of EPSBO4 (Table 2). EPSBO After Laparoscopy In a study of intestinal obstruction after laparoscopic procedures, Duran et al reported an overall prevalence of small bowel obstruction to be 0.21% and EPSBO constituted 88% of all the obstructions.14 Cholecystectomy, trans-peritoneal hernia repair, and appendectomy were the 3 most common procedures associated with post-laparoscopic EPSBO. The prevalence was higher compared with the open surgery series by Stewart et al (0.11%, 2.5%, and 0.16% vs 0.06%, 0.10%, and 0.65%, reCURRENT SURGERY • Volume 59/Number 3 • May/June 2002
4 2
mechanical small bowel obstruction, the differentiation from high-pitched tinkling and uncoordinated bowel sounds that are heard in the postoperative period is difficult.3 When 2 or more of the above clinical features are present, the likelihood of reoperation is greater, as demonstrated by Fryckberg and Phillips; 78% percent of patients with 3 out of 4 clinical signs ultimately required re-operation.6
10
2
Radiological Investigations in EPSBO
14 9
4 2
The first radiological study usually ordered when a postoperative patient develops abdominal distension is an erect and supine plain abdominal x-ray. The presence of distended small bowel loops with air-fluid levels, with paucity of colonic gas, could suggest a mechanical small bowel obstruction. However, the interpretation of plain films is difficult in the postoperative patient, as both the postoperative ileus and EPSBO manifest with distended small bowel loops and some air in the large bowel. A gas-filled colon is difficult to visualize, especially when a colectomy has been done. The accuracy of plain films in this setting has been reported to vary from 19% to 73%.6,17 Upper gastrointestinal contrast studies are useful in making the diagnosis of EPSBO; however, in 1 study, 38% of patients in whom orally administered contrast passed into the colon still required operation.18 In the series by Pickleman and Lee,4 small bowel contrast follow-though studies were able to identify a definite point of obstruction in 72% of patients. Water-soluble contrast material has to be used as it eliminates the risk of peritoneal contamination with barium in the event of anastamotic leakage and has the additional advantage of being therapeutic in partial small bowel obstructions, as demonstrated by Assalia et al.19 Computed tomography scan is valuable in differentiating postoperative ileus from mechanical obstruction. According to Frager et al,17 CT does so with a sensitivity and specificity of 100% in contrast to clinical and plain abdominal x-rays evaluation (sensitivity of 19% and specificity of 100%). However, CT signs of partial small bowel obstruction overlap with paralytic ileus. This distinction is clinically less important as most of the patients improve with conservative measures.17 A CT scan has the additional advantage of being able to identify intraabdominal causes of persistent ileus (eg, abscesses, peri-anastomotic phlegmon) and point out the actual causes of EPSBO (eg, facial dehiscence and internal herniation).
TABLE 2. Operations with High Incidence of EPSBO Operation
Incidence (%)
Colectomy, especially of the left colon Abdominoperineal resection Complicated groin hernia operations Appendectomy for perforated appendicitis Small bowel resection Penetrating trauma with small bowel injury Hysterectomy Negative laparotomy
28 5 5.3
7 5.3
References 2
4 2
spectively). The mechanism of obstruction was caused by adhesions or bands in half of the patients and small bowel incarceration at the port site in the other half. All port site herniations involved 10- or 12-mm ports, and the umbilical port was the commonest site. In most (66%) port site herniations, adequate fascial closure was not performed.14 Even a 5-mm port site incarceration leading to EPSBO has been described.15 When a 5-mm port site is used to pass instruments several times in different directions, enlargement of the fascial defect occurs and fascial closure should be considered in this situation.15 Spilled gallstones during laparoscopic cholecystectomy can lead to the development of inflammatory adhesions causing EPSBO.16 Diagnosis The diagnosis of EPSBO is difficult because abdominal pain, distension, vomiting, and diminished bowel activity commonly accompanies abdominal operations for a variable length of time and is loosely termed as postoperative ileus. In addition, use of nasogastric tubes and administration of analgesics further complicates the issue. Clinical Features of EPSBO Although the triad of colicky abdominal pain, vomiting, and absolute constipation along with abdominal distension are pathognomonic for mechanical small bowel obstructions, several differences are found in the immediate postoperative period. Incisional pain and analgesia tend to mask the pain, which is often attributed to “gas pains.” In 1 series, abdominal pain was present in 15 out of 26 patients.6 Vomiting is absent if nasogastric tube is in place when EPSBO develops; it was present in 82% and 76% of patients in 2 series, respectively.4,6 Absolute constipation is rare with patients continuing to pass small amounts of flatus and stool that does not exclude EPSBO.3,6 Distension is the only clinical feature that is consistently reported with EPSBO—present in 76% to 81% of the patients.4,6 Although the presence of obstructive bowel sounds that accompany colicky abdominal pain are highly suggestive of CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
Management of EPSBO After “Open” Surgery Once EPSBO is suspected, the initial management is similar to other forms of small bowel obstruction: nasogastric aspiration, replacement of fluid and electrolytes, and careful serial clinical evaluation. The use of long intestinal tubes has not been found to be helpful in this condition and may in fact increase the complication rate.6 One of the major issues in the management of patients with small bowel obstruction is the risk of strangulation. It is well recognized that clinical signs laboratory tests 291
TABLE 3. Intestinal Strangulation in EPSBO References 2* 3* 4 5 6 8 TOTAL
Number cases
Re-operation Required (%)
56 26 101 41 26 44 294
56 26 23 11 15 18 149
(22.77) (26.8) (58) (44) (50.7)
Intestinal strangulation (%) 1 3 0 1 2 0 7
(1.8) (11.5) (2.4) (7.6) (2.3)
Mortality (%) 10 4 7 1 2 2 26
(17.8) (15.3) (7) (2.4) (8) (5) (9)
*These series reported only the patients who underwent surgery for EPSBO.
and radiological investigations are unreliable to detect strangulation.20 Notably, however, unlike other forms of intestinal obstruction, the incidence of strangulation in patients with EPSBO is much less frequent.21 Table 3 summarizes the incidence of strangulation in EPSBO: in the collected series of 294 patients, only 7 patients (2.3%) developed intestinal strangulation. Because of the minute danger of intestinal strangulation in the setting of EPSBO, the prevailing consensus maintains that nonoperative management (eg, nasogastric decompression and parenteral nutritional) support should initially be attempted in every patient with EPSBO. Disagreement exists, however, regarding the duration of nonoperative treatment. Ellozy et al recommends re-exploration for patients that fail to resolve with in 1 week.7 The patients that resolve without operation usually do so within 2 weeks: 96% of patients in Pickleman and Lee’s series4 and 86% in the series by Quatromini et al.5 It seems, however, that spontaneous resolution beyond the 10th postoperative day is unlikely.4 In our collective series of EPSBO (Table 3), 149 patients out of 294 (50.68%) failed nonoperative management and were operated upon. Overall mortality rate of laparotomy for EPSBO was 8.8%. Management of Post-laparoscopic EPSBO In contrast, when EPSBO follows a laparoscopic surgery, early operation is advised as nearly half of the cases are caused by port site herniation of the small bowel.14 Incarcerations have been reported even in 5-mm trocar holes.15 Nonoperative management was not successful in all patients with EPSBO in the series reported by Velasco.22
REFERENCES 1. Nadrowski L. Paralytic ileus: recent advances in patho-
physiology and treatment. Curr Surg. 1983;40:260. 2. Stewart RM, Page CP, Brender J, et al. The incidence and
risk of early post-operative small bowel obstruction. Am J Surg. 1987;154:643-647. 3. Sykes PA, Schofield PF. Early postoperative small bowel
obstruction. Br J Surg. 1974;61:594-600. 292
4. Pickleman J, Lee. RM. Management of patients with sus-
pected early post-operative small bowel obstruction. Ann Surg. 1989;210:216-219. 5. Quatromoni JC, Rosoff L Sr, Halls JM, Yellin AE. Early
post-operative small bowel obstruction. Ann Surg. 1980; 191:72-74. 6. Frykberg ER, Phillips JW. Obstruction of the small bowel
in the early postoperative period. South Med J. 1989;82: 169-173. 7. Ellozy S, Harris M, Bauer J, et al. Early postoperative
small-bowel obstruction: a prospective evaluation of 242 consecutive abdominal operations. Dis Colon Rectum. 2001;44:A5-A26. 8. Siporin K, Hiatt JR, Treiman RL. Small bowel obstruc-
tion after abdominal aortic surgery. Am Surg. 1993;59: 846-849. 9. Parker MC, Ellis H, Moran BJ, et al. Postoperative adhe-
sions: ten-year follow-up of 12,584 patients undergoing lower abdominal surgery. Dis Colon Rectum. 2001;44: 822-830. 10. Dijkstra FR, Nieuwenhuijzen M, Reijnen MMPJ, van
Goor H. Recent clinical developments in pathophysiology, epidemiology, diagnosis and treatment of intra-abdominal adhesions. Scand J Gastroenterol. 2000;S232:5259. 11. Liakakos T, Thomakos N, Fine PM, et al. Peritoneal ad-
hesions: etiology, pathophysiology and clinical significance. Recent advances in prevention and management. Dig Surg. 2001;18:260-273. 12. Holmdahl L, Eriksson E, Eriksson BI, Risberg B. Depres-
sion of peritoneal fibrinolysis during surgery is a local response to trauma. Surgery. 1998;123:539-544. 13. Sannella NA. Early and late obstruction of small bowel
after abdominoperineal resection. Am J Surg. 1975;130: 270-272. 14. Duran JJ, Hay JM, Msika S, et al. Prevalence and mechCURRENT SURGERY • Volume 59/Number 3 • May/June 2002
anisms of small intestinal obstruction following laparoscopic abdominal surgery. Arch Surg. 2000;135:208-212. 15. Reardon PR. Hernia at 5-mm laparoscopic port site pre-
senting as early postoperative small bowel obstruction. J Laparoendosc Adv Surg Tech A. 1999;9:523-525. 16. Huynh T, Mercer CD. Early postoperative small bowel
obstruction caused by spilled gallstones during laparoscopic cholecystectomy. Surgery. 1996;119:352-353. 17. Frager DH, Baer JW, Rothpearl A, Bossart PA. Distinc-
tion between postoperative ileus and mechanical smallbowel obstruction: value of CT compared to clinical and other radiographic findings AJR. 1995;164:891-894. 18. Dunn JT, Halls JM, Berne TV. Roentgenographic con-
trast studies in acute small bowel obstruction. Arch Surg. 1984;119:1305-1308. 19. Assalia A, Schein M, Kopelman D, Hirshberg A, Has-
monai M. Therapeutic effect of oral gastrografin in adhesive, partial small bowel obstruction. Surgery. 1994;115: 433-437. 20. Sarr MG, Bulkley GB, Zuidema GD. Preoperative recog-
nition of intestinal strangulation obstruction. Am J Surg. 1983;145:176-182. 21. Spears H, Petrelli NJ, Herrera L, Mittleman A. Treatment
of bowel obstruction after operation for colorectal carcinoma. Am J Surg. 1988;155:383-386. 22. Velasco JM. Postlaparoscopic small bowel obstruction.
Rethinking its management. Surg Endosc. 1998;12:10431045. SAI B. S. SAJJA, MD PANDURANGA R. YENUMULA, MD Department of Surgery Bronx Lebanon Hospital Center Bronx, New York
EDITORIAL COMMENT The postoperative fart is the best music to the surgeon’s ears . . . .” So, a few days ago you removed this patient’s perforated appendix, you gave him antibiotics for 2 to 3 days, and by today, you expected him to eat and go home. Instead, your patient lies in bed with a long face and a distended abdomen, vomiting bile from time to time. What is the problem? Is it “just” a “paralytic ileus,” or are we dealing with mechanical small bowel obstruction (SBO)? Ileus Ileus is a “normal” phenomenon after abdominal operations— it’s magnitude directly proportional to the magnitude of the CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
operation. Unlike mechanical intestinal obstruction, which involves a segment of bowel, postoperative ileus concerns the whole length of the gut, from the stomach to the rectum. Physiological postoperative ileus resolves gradually. The small bowel resumes activity almost immediately, followed, a day or so later, by the stomach, and then the colon, being the laziest, is the last to start moving. The magnitude of the postoperative ileus correlates to some extent with that of the operation performed and the specific underlying condition. Major dissections, prolonged intestinal displacement and exposure, denuded and inflamed peritoneum, and residual intraperitoneal or retroperitoneal pus or clots are associated with a prolonged ileus. Thus, for example, after simple appendectomy for nonperforated appendicitis, the ileus is almost nonexistent, whereas after a laparotomy for a ruptured abdominal aortic aneurysm (AAA), expect the ileus to be prolonged. Common postoperative factors, which can aggravate ileus, are the administration of opiates and electrolyte imbalance. Although the “physiological” postoperative ileus is “diffuse,” ileus caused by complications may be “local.” A classic example of a local ileus is a postoperative abscess, which may “paralyze” an adjacent segment of bowel. Early Postoperative Mechanical Intestinal Obstruction Early postoperative SBO is defined as one developing immediately after the operation or within 2 weeks. Two primary mechanisms are responsible: adhesions and internal hernia. Early post-laparotomy adhesions are immature, inflammatory, poor in collagen (thus, “soft”), and vascular. Such characteristics indicate that early adhesions may resolve spontaneously and that its surgical lysis may be difficult and “bloody.” Postoperative adhesions may be diffuse, involving the whole length of the small bowel in multiple sites, as occasionally seen after extensive lysis of adhesion for SBO. Localized obstructing adhesions may also develop at the operative site with the bowel adherent, for instance, to an exposed Marlex mesh or a raw peritoneal surface. The operation also may create new potential spaces into which the bowel can herniate to be obstructed, forming internal hernias. Typical examples are the partially closed pelvis after abdominoperineal resection, or the space behind an emerging colostomy. The narrower the opening into the space, the more likely is the bowel to be trapped. Diagnosis Failure of the patient to eat, pass flatus, or evacuate his bowel within 5 days after a laparotomy signifies a persistent ileus. The abdomen is usually distended and silent to auscultation. Plain abdominal x-ray typically discloses a significant gaseous distension of both the small bowel and the colon. The diagnosis of SBO in the recently operated abdomen is much subtler. Textbooks teach that on abdominal auscultation, ileus is silent and SBO is noisy; this may be theoretically true, but almost impossible to assess in the recently operated belly. If the patient has 293
TABLE 4. Clinical Considerations in EPSBO Primary operation
Question
Consideration
Laparotomy for SBO Abdomino-perineal resection Colostomy, ileostomy Laparoscopy Intestinal anastomosis
Was the obstructing point dealt with? Is the small bowel prolapsing into a pelvic space (CT)? Is the small bowel caught behind the stoma (contrast/CT)? Is the bowel caught in a trocar site (CT)? See below*
If If If If
not—consider an earlier re-operation yes—consider an earlier re-operation yes—consider an earlier operation yes—operate immediately
CT ⫽ Computed tomography; SBO ⫽ small bowel obstruction.
already passed flatus or defecated and then ceases to manifest these comforting features, SBO is the most likely diagnosis. The truth is that in most instances, the patient will improve spontaneously without you ever knowing whether it was a SBO or “just” an ileus. The natural tendency of the operating surgeon is to attribute the “failure to progress” to an ileus rather than to SBO and to procrastinate. Procrastination is not a good idea, however. A distended and noneating patient is prone to the iatrogenic hazards of the nasogastric tube, intravenous lines, parenteral nutrition, and bed rest. Be active and proceed with diagnostic steps in parallel to therapy. Management • Nasogastric tube, if not already in situ, has to be inserted to decompress the stomach, prevent aerophagia, relieve nausea and vomiting, and measure gastric residue. Carefully search and correct, if present, potential causes of prolonged ileus. • Opiates are the most common promoters of ileus; pain should be controlled but not excessively and not for too long. • Electrolyte imbalances are to be measured and corrected. • The possibility that an intra-abdominal complication is the cause of the ileus or SBO has to be considered and excluded. A hematoma, an abscess, an anastomotic leak, postoperative pancreatitis, and postoperative acalculus cholecystitis all can produce ileus or mimic SBO. • Significant hypoalbuminemia leads to generalized edema-involving the bowel too. Edematous and swollen bowel does not move well; this is called hypoalbuminemic entropathy and should be considered. Practically speaking, if on the fifth post-laparotomy day the patient still presents features of ileus/SBO, we recommend a plain abdominal x-ray to assess the gas pattern. If the latter suggests an ileus or SBO, a “Gastrografin challenge”2 may be useful in relieving both conditions. Gastrografin Challenge Gastrografin, a hyperosmolar agent that promotes intestinal “hurry,” plays 2 roles: diagnostic-prognostic and therapeutic. After the initial gastric decompression, 100 ml of Gastrografin are instilled through the nasogastric tube, which is then clamped for 2 hours. Four to 6 hours later, a simple plain abdominal x-ray is obtained. This is not a formal radiological study under fluoroscopy and not done by the radiologist, who 294
anyway, usually prefers to install barium. Presence of contrast in the large bowel proves that the obstruction is partial or that it is “ileus.” In most of these instances, the Gastrografin is passed per rectum. In partial SBO and ileus, Gastrografin is often therapeutic, as it expedites the resolution of the obstructing episode.1,2 On the other hand, failure of Gastrografin to reach the colon within 6 hours indicates a complete obstruction. The results of the study should be correlated with the whole clinical picture. Note that Gastrografin may pass across a chronic SB narrowing. Thus, for the obstructive episode to be considered as “resolved,” the abdominal symptoms and signs should disappear as well. When the clinical picture suggests one of the above-mentioned intra-abdominal causes of persistent ileus, an abdominal CT, combined with oral Gastrografin is indicated to pinpoint the problem and, at times, to guide treatment. When to Operate? As emphasized in the preceding section, intestinal strangulation almost never occurs in this situation and spontaneous resolution is common. Resolution of SBO, however, rarely occurs beyond the tenth postoperative day. In the absence of intra-or extra-abdominal causes for ileus, and when the “ileus” does not respond to the gastrografin challenge, the diagnosis is SBO. Do not rush to re-operate; treat conservatively while providing nutritional support. Lack of resolution beyond 10 to 14 days is an indication for re-laparotomy, which in itself may be difficult and hazardous because of the typical early dense and vascular adhesions cementing the bowel at many points. Special Problems When confronted with features of complete SBO demonstrated by the contrast study or CT, the surgeon should correlate these findings with information deriving from the primary operation (Table 4). Anastomotic Obstruction A bowel anastomosis at any level may cause early postoperative upper gastrointestinal, small bowel, or colonic obstruction. Faulty technique is usually the cause. A self-limiting “mini” anastomotic leak is often responsible but under-diagnosed. Diagnosis is reached with a contrast study or CT. Most such early CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
postoperative anastomotic obstructions are “soft” and edematous, resolving spontaneously within a week or 2.
REFERENCES 1. Assalia A, Schein M, Kopelman D, Hirshberg A, Hash-
Prevention Postoperative ileus and SBO are prevented by sound operative technique and attention to details. Gentle dissection and handling of tissues, careful hemostasis to avoid hematoma formation, leaving as little foreign bodies as possible, not denuding the peritoneum unnecessarily, not creating orifices for internal hernias, and not catching loops of bowel during abdominal closure, are self-explanatory essentials.
monai M. Therapeutic effect of oral Gastrografin in adhesive, partial small-bowel obstruction: a prospective randomized trial. Surgery. 1994;115:433-437. 2. Zer M, Kaznelson D, Feigenberg Z, Dintsman M. The
value of Gastrografin in the differential diagnosis of paralytic ileus versus mechanical intestinal obstruction: a critical review and report of two cases. Dis Colon Rectum. 1977;20:573-579.
Summary In a patient who does not move his bowels 5 days after laparotomy, exclude and treat causes of persistent ileus, treat SBO conservatively as long as indicated, think about specific causes of SBO (eg, herniation at a laparoscopic trocar site), and reoperate when necessary. In most instances, ileus/SBO will resolve spontaneously, and one never knows what was the cause. MOSHE SCHEIN, MD Department of Surgery Bronx Lebanon Hospital Center Bronx, New York
CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
CORRECT ANSWERS TO THE QUIZ ON PAGE 2 What Is Your Diagnosis? Both 1 and 2 are possible. What Would You Do Now? 6. (The patient is on his third postoperative day and “permitted” to have an ileus.)
295
Early Postoperative Intestinal Obstruction THE CASE A 42-year-old, otherwise healthy, male patient underwent an operation for acute appendicitis through a transverse, musclesplitting, right lower quadrant incision. A perforated appendix was resected, and a small quantity of localized pus was sucked out. The wound was closed in layers, including the skin, and no drain was left in situ. Wide spectrum antibiotics, which were started before the operation, were continued postoperatively. Nasogastric tube was removed at the end of the procedure. Intramuscular opiate-analgesia was prescribed. On postoperative day 1: The patient was afebrile and ambulating. His abdomen was minimally distended and tender around the incision site. Auscultation revealed “a few bowel sounds.” Oral clear fluids were ordered. On postoperative day 2: The patient reported that he passed flatus. Soft diet was ordered. At night, the patient vomited a large quantity of bile-containing gastric contents. The Intern on call inserted a nasogastric tube. On postoperative day 3: The patient is afebrile, and his abdomen is soft, non-tender, and minimally distended. His bowel sounds are judged as “active.” Nasogastric output during the 8 hours since insertion was 700 ml of deeply green-stained fluid. White blood cell count was 10,500; levels of serum urea and electrolytes are normal. Plain abdominal radiograph reveals free intra-abdominal air and marked dilatation of the small bowel with air-fluid levels. The colon is not dilated and contained some air. What Is Your Diagnosis? 1. 2. 3. 4. 5. 6.
“Early” adhesive mechanical small bowel obstruction Paralytic ileus “Early” adhesive large bowel obstruction Acute stress gastritis Excessive aerophagia Both A and B are possible
What Would You Do Now? 1. 2. 3. 4. 5. 6.
Order a computed tomography (CT) scan of the abdomen Change the antibiotics Order a small bowel series with barium Order small bowel series with gastrografin Perform a diagnostic laparoscopy None of the above
See correct answers on page X. Correspondence: Inquiries to Moshe Schein, MD, Department of Surgery, Bronx Lebanon Hospital Center, 1650 Selwyn Avenue, 4th Floor, Suite 4F, Bronx, NY 10457; (718) 960-1312; e-mail: [email protected]
MOSHE SCHEIN, MD Department of Surgery Bronx Lebanon Hospital Center Bronx, New York
THE DISCUSSION OF THE CASE Early postoperative small bowel obstruction (EPSBO)—the “early” referring usually to the first 30 postoperative days— has long been recognized as a distinct clinical entity that is often difficult to differentiate from postoperative ileus. The pathophysiology, diagnosis, and management of EPSBO differ in several respects from that of small bowel obstruction occurring in a patient with virgin abdomen (no prior intraperitoneal surgery) or that of adhesive obstruction at a time remote from the operation. Although adhesions account for most small bowel obstructions in the early postoperative period, several other factors, including technical problems at the time of operation and internal herniation through mesenteric defects, have to be considered. The definition of EPSBO has varied from clinical diagnosis alone, to symptoms and signs along with radiographic evidence, to operation— confirmed obstruction, causing further difficulties in estimating the true incidence and in development of a rational treatment plan. Definition and Incidence of EPSBO To reliably define EPSBO, it is essential to differentiate it from postoperative ileus. All postoperative patients experience ileus for a variable period that depends on several factors: the magnitude of surgery, general condition of the patient (eg, malnutrition may cause severe hypoalbuminemia, which in turns results in swelling of the bowel), associated electrolyte abnormalities, and the occurrence of complications like postoperative pneumonia or urinary tract infection. Small bowel is the first to recover peristaltic activity a few hours after the operation, followed by the stomach in 8 to 48 hours; the colon remains inactive for 48 to 72 hours and is the last organ to recover.1 The differentiation becomes more difficult because of the incisional pain and the frequent administration of analgesics, which posses their own paralytic activity on the large bowel. Stewart et al defined EPSBO as temporary return of bowel function followed by distension and obstipation occurring within 4 weeks of laparotomy and subsequent confirmation of obstruction at re-operation.2 Using this definition, they reported an incidence of 0.69% in a prospective study of 8098 patients. Sykes and Schofield also utilized a similar definition: a complete mechanical small bowel obstruction occurring post-
CURRENT SURGERY • © 2002 by the Association of Program Directors in Surgery Published by Elsevier Science Inc.
0149-7944/02/$22.00 PII S0149-7944(02)00625-6
289
operatively (during the same admission), with subsequent confirmation at re-laparotomy or autopsy.3 Pickleman and Lee, on the other hand, relied on symptoms and signs of obstruction for 7 days or longer at any time within the 30-day period or symptoms and signs of obstruction occurring from 7 to 30 days after the operation, lasting any number of days.4 Quatromoni et al utilized abdominal x-rays in addition to clinical signs and symptoms of small bowel obstruction, again occurring within 30 days of operation.5 Similarly, Frykberg and Phillips considered EPSBO to be present when at least 1 of the 4 standard clinical features of bowel obstruction (abdominal pain, vomiting, distension, and obstipation) were present along with radiographic confirmation, as interpreted by a radiologist.6 In another prospective study, Ellozy et al showed that EPSBO occurred in 9.5% of patients.7 In this study, EPSBO was considered present when crampy abdominal pain, vomiting, and radiographic findings consistent with intestinal obstruction were present after an initial return of bowel function within 30 days after surgery. In a retrospective review of 1475 patients after abdominal aortic surgery, Siporin et al showed the incidence of EPSBO to be 2.9%.8 It is likely that the definition used by Stewart et al2 underestimates the problem by excluding the cases that resolve spontaneously, and most authors have utilized a definition similar to the one used by Ellozy et al.7
Inflammatory causes. A local inflammatory process, such as an intra-abdominal abscess, may lead to EPSBO by causing small bowel adherence to the abscess wall. These septic adhesions were responsible for EPSBO in 8% and 4% of cases reported in 2 series.4,6 In another series, intra-peritoneal abscess were present in 12 of 26 cases of EPSBO.3 Other rare causes of EPSBO include intussusception and intramural intestinal hematoma.4,6 Table 1 summarizes the various origins of EPSBO.
Pathophysiology and Causes of EPSBO
The Risk of EPSBO According to the Procedure
Adhesions. Most cases of EPSBO resolve with nonoperative treatment, and it is likely that adhesions are the causative factor. Also, in patients that require surgery, the usual cause of obstruction is adhesions—the cause of EPSBO in 91%4 and 92%2 of patients. Adhesion formation follows any operative peritoneal injury or that caused by peritoneal contamination and infection. This leads to an inflammatory response with activation of complement and coagulation cascades along with exudation of fibrinogen-rich fluid. Thrombin converts fibrinogen to fibrin, which attaches the adjoining damaged surfaces. At this stage, if fibrin is not degraded, fibroblasts propagate in this matrix and collagen deposition occurs, leading to the conversion of fibrinous adhesions to fibrous adhesions. If fibrin degradation is complete, fibrinous adhesions resolve and mesothelial regeneration becomes complete. However, peritoneal injury-surgery or peritonitis has been shown to depress fibrinolytic activity. This early balance between fibrin formation and its degradation in the peritoneal cavity during and after surgery seems to be the major determinant of postoperative adhesion formation.9 –12 Internal herniation. Any defect within the peritoneal cavity has the potential to cause EPSBO by internal herniation. When a mesenteric or omental defect is created, or an opening is left in the “gutters”— behind a colostomy or enterostomy— small bowel may herniate through, leading to EPSBO. In one series, herniation through a pelvic floor defect after abdomino290
TABLE 1. Causes of EPSBO Adhesions Internal herniation Volvulus Fascial dehiscence Abdominal wall sutures Intra-abdominal abscess Intra-abdominal hematoma Obstruction caused by preexisting disease Intussusception Missed pathology (eg, another small bowel bezoar). EPSBO ⫽ early postoperative small bowel obstruction.
perineal resection was reported to be responsible for 5 out of 13 cases of EPSBO.13
The risk of EPSBO seems to vary depending on the type of the precipitating surgical procedure. Operations in the supra-colic compartment (eg, open cholecystectomy) have lower risk compared with operations in the infra-colic compartment.4,5 According to Stewart et al, the operations most frequently associated with EPSBO were groin hernia operations associated with small bowel obstruction, operations on the left side of the colon and rectum, and small bowel operations.2,13 Hepatobiliary operations had the lowest risk. After appendectomy, increased risk of EPSBO was observed for perforated appendicitis but not for nonperforated appendicitis.2 In the series reported by Fryckberg and Phillips, colon was the organ most commonly operated upon initially and 77% of the procedures were emergencies; 11 out of 26 cases were for trauma.6 In Pickleman and Lee’s experience, colectomy, exploratory laparotomy, and enterectomy constituted high-risk operations for the development of EPSBO4 (Table 2). EPSBO After Laparoscopy In a study of intestinal obstruction after laparoscopic procedures, Duran et al reported an overall prevalence of small bowel obstruction to be 0.21% and EPSBO constituted 88% of all the obstructions.14 Cholecystectomy, trans-peritoneal hernia repair, and appendectomy were the 3 most common procedures associated with post-laparoscopic EPSBO. The prevalence was higher compared with the open surgery series by Stewart et al (0.11%, 2.5%, and 0.16% vs 0.06%, 0.10%, and 0.65%, reCURRENT SURGERY • Volume 59/Number 3 • May/June 2002
4 2
mechanical small bowel obstruction, the differentiation from high-pitched tinkling and uncoordinated bowel sounds that are heard in the postoperative period is difficult.3 When 2 or more of the above clinical features are present, the likelihood of reoperation is greater, as demonstrated by Fryckberg and Phillips; 78% percent of patients with 3 out of 4 clinical signs ultimately required re-operation.6
10
2
Radiological Investigations in EPSBO
14 9
4 2
The first radiological study usually ordered when a postoperative patient develops abdominal distension is an erect and supine plain abdominal x-ray. The presence of distended small bowel loops with air-fluid levels, with paucity of colonic gas, could suggest a mechanical small bowel obstruction. However, the interpretation of plain films is difficult in the postoperative patient, as both the postoperative ileus and EPSBO manifest with distended small bowel loops and some air in the large bowel. A gas-filled colon is difficult to visualize, especially when a colectomy has been done. The accuracy of plain films in this setting has been reported to vary from 19% to 73%.6,17 Upper gastrointestinal contrast studies are useful in making the diagnosis of EPSBO; however, in 1 study, 38% of patients in whom orally administered contrast passed into the colon still required operation.18 In the series by Pickleman and Lee,4 small bowel contrast follow-though studies were able to identify a definite point of obstruction in 72% of patients. Water-soluble contrast material has to be used as it eliminates the risk of peritoneal contamination with barium in the event of anastamotic leakage and has the additional advantage of being therapeutic in partial small bowel obstructions, as demonstrated by Assalia et al.19 Computed tomography scan is valuable in differentiating postoperative ileus from mechanical obstruction. According to Frager et al,17 CT does so with a sensitivity and specificity of 100% in contrast to clinical and plain abdominal x-rays evaluation (sensitivity of 19% and specificity of 100%). However, CT signs of partial small bowel obstruction overlap with paralytic ileus. This distinction is clinically less important as most of the patients improve with conservative measures.17 A CT scan has the additional advantage of being able to identify intraabdominal causes of persistent ileus (eg, abscesses, peri-anastomotic phlegmon) and point out the actual causes of EPSBO (eg, facial dehiscence and internal herniation).
TABLE 2. Operations with High Incidence of EPSBO Operation
Incidence (%)
Colectomy, especially of the left colon Abdominoperineal resection Complicated groin hernia operations Appendectomy for perforated appendicitis Small bowel resection Penetrating trauma with small bowel injury Hysterectomy Negative laparotomy
28 5 5.3
7 5.3
References 2
4 2
spectively). The mechanism of obstruction was caused by adhesions or bands in half of the patients and small bowel incarceration at the port site in the other half. All port site herniations involved 10- or 12-mm ports, and the umbilical port was the commonest site. In most (66%) port site herniations, adequate fascial closure was not performed.14 Even a 5-mm port site incarceration leading to EPSBO has been described.15 When a 5-mm port site is used to pass instruments several times in different directions, enlargement of the fascial defect occurs and fascial closure should be considered in this situation.15 Spilled gallstones during laparoscopic cholecystectomy can lead to the development of inflammatory adhesions causing EPSBO.16 Diagnosis The diagnosis of EPSBO is difficult because abdominal pain, distension, vomiting, and diminished bowel activity commonly accompanies abdominal operations for a variable length of time and is loosely termed as postoperative ileus. In addition, use of nasogastric tubes and administration of analgesics further complicates the issue. Clinical Features of EPSBO Although the triad of colicky abdominal pain, vomiting, and absolute constipation along with abdominal distension are pathognomonic for mechanical small bowel obstructions, several differences are found in the immediate postoperative period. Incisional pain and analgesia tend to mask the pain, which is often attributed to “gas pains.” In 1 series, abdominal pain was present in 15 out of 26 patients.6 Vomiting is absent if nasogastric tube is in place when EPSBO develops; it was present in 82% and 76% of patients in 2 series, respectively.4,6 Absolute constipation is rare with patients continuing to pass small amounts of flatus and stool that does not exclude EPSBO.3,6 Distension is the only clinical feature that is consistently reported with EPSBO—present in 76% to 81% of the patients.4,6 Although the presence of obstructive bowel sounds that accompany colicky abdominal pain are highly suggestive of CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
Management of EPSBO After “Open” Surgery Once EPSBO is suspected, the initial management is similar to other forms of small bowel obstruction: nasogastric aspiration, replacement of fluid and electrolytes, and careful serial clinical evaluation. The use of long intestinal tubes has not been found to be helpful in this condition and may in fact increase the complication rate.6 One of the major issues in the management of patients with small bowel obstruction is the risk of strangulation. It is well recognized that clinical signs laboratory tests 291
TABLE 3. Intestinal Strangulation in EPSBO References 2* 3* 4 5 6 8 TOTAL
Number cases
Re-operation Required (%)
56 26 101 41 26 44 294
56 26 23 11 15 18 149
(22.77) (26.8) (58) (44) (50.7)
Intestinal strangulation (%) 1 3 0 1 2 0 7
(1.8) (11.5) (2.4) (7.6) (2.3)
Mortality (%) 10 4 7 1 2 2 26
(17.8) (15.3) (7) (2.4) (8) (5) (9)
*These series reported only the patients who underwent surgery for EPSBO.
and radiological investigations are unreliable to detect strangulation.20 Notably, however, unlike other forms of intestinal obstruction, the incidence of strangulation in patients with EPSBO is much less frequent.21 Table 3 summarizes the incidence of strangulation in EPSBO: in the collected series of 294 patients, only 7 patients (2.3%) developed intestinal strangulation. Because of the minute danger of intestinal strangulation in the setting of EPSBO, the prevailing consensus maintains that nonoperative management (eg, nasogastric decompression and parenteral nutritional) support should initially be attempted in every patient with EPSBO. Disagreement exists, however, regarding the duration of nonoperative treatment. Ellozy et al recommends re-exploration for patients that fail to resolve with in 1 week.7 The patients that resolve without operation usually do so within 2 weeks: 96% of patients in Pickleman and Lee’s series4 and 86% in the series by Quatromini et al.5 It seems, however, that spontaneous resolution beyond the 10th postoperative day is unlikely.4 In our collective series of EPSBO (Table 3), 149 patients out of 294 (50.68%) failed nonoperative management and were operated upon. Overall mortality rate of laparotomy for EPSBO was 8.8%. Management of Post-laparoscopic EPSBO In contrast, when EPSBO follows a laparoscopic surgery, early operation is advised as nearly half of the cases are caused by port site herniation of the small bowel.14 Incarcerations have been reported even in 5-mm trocar holes.15 Nonoperative management was not successful in all patients with EPSBO in the series reported by Velasco.22
REFERENCES 1. Nadrowski L. Paralytic ileus: recent advances in patho-
physiology and treatment. Curr Surg. 1983;40:260. 2. Stewart RM, Page CP, Brender J, et al. The incidence and
risk of early post-operative small bowel obstruction. Am J Surg. 1987;154:643-647. 3. Sykes PA, Schofield PF. Early postoperative small bowel
obstruction. Br J Surg. 1974;61:594-600. 292
4. Pickleman J, Lee. RM. Management of patients with sus-
pected early post-operative small bowel obstruction. Ann Surg. 1989;210:216-219. 5. Quatromoni JC, Rosoff L Sr, Halls JM, Yellin AE. Early
post-operative small bowel obstruction. Ann Surg. 1980; 191:72-74. 6. Frykberg ER, Phillips JW. Obstruction of the small bowel
in the early postoperative period. South Med J. 1989;82: 169-173. 7. Ellozy S, Harris M, Bauer J, et al. Early postoperative
small-bowel obstruction: a prospective evaluation of 242 consecutive abdominal operations. Dis Colon Rectum. 2001;44:A5-A26. 8. Siporin K, Hiatt JR, Treiman RL. Small bowel obstruc-
tion after abdominal aortic surgery. Am Surg. 1993;59: 846-849. 9. Parker MC, Ellis H, Moran BJ, et al. Postoperative adhe-
sions: ten-year follow-up of 12,584 patients undergoing lower abdominal surgery. Dis Colon Rectum. 2001;44: 822-830. 10. Dijkstra FR, Nieuwenhuijzen M, Reijnen MMPJ, van
Goor H. Recent clinical developments in pathophysiology, epidemiology, diagnosis and treatment of intra-abdominal adhesions. Scand J Gastroenterol. 2000;S232:5259. 11. Liakakos T, Thomakos N, Fine PM, et al. Peritoneal ad-
hesions: etiology, pathophysiology and clinical significance. Recent advances in prevention and management. Dig Surg. 2001;18:260-273. 12. Holmdahl L, Eriksson E, Eriksson BI, Risberg B. Depres-
sion of peritoneal fibrinolysis during surgery is a local response to trauma. Surgery. 1998;123:539-544. 13. Sannella NA. Early and late obstruction of small bowel
after abdominoperineal resection. Am J Surg. 1975;130: 270-272. 14. Duran JJ, Hay JM, Msika S, et al. Prevalence and mechCURRENT SURGERY • Volume 59/Number 3 • May/June 2002
anisms of small intestinal obstruction following laparoscopic abdominal surgery. Arch Surg. 2000;135:208-212. 15. Reardon PR. Hernia at 5-mm laparoscopic port site pre-
senting as early postoperative small bowel obstruction. J Laparoendosc Adv Surg Tech A. 1999;9:523-525. 16. Huynh T, Mercer CD. Early postoperative small bowel
obstruction caused by spilled gallstones during laparoscopic cholecystectomy. Surgery. 1996;119:352-353. 17. Frager DH, Baer JW, Rothpearl A, Bossart PA. Distinc-
tion between postoperative ileus and mechanical smallbowel obstruction: value of CT compared to clinical and other radiographic findings AJR. 1995;164:891-894. 18. Dunn JT, Halls JM, Berne TV. Roentgenographic con-
trast studies in acute small bowel obstruction. Arch Surg. 1984;119:1305-1308. 19. Assalia A, Schein M, Kopelman D, Hirshberg A, Has-
monai M. Therapeutic effect of oral gastrografin in adhesive, partial small bowel obstruction. Surgery. 1994;115: 433-437. 20. Sarr MG, Bulkley GB, Zuidema GD. Preoperative recog-
nition of intestinal strangulation obstruction. Am J Surg. 1983;145:176-182. 21. Spears H, Petrelli NJ, Herrera L, Mittleman A. Treatment
of bowel obstruction after operation for colorectal carcinoma. Am J Surg. 1988;155:383-386. 22. Velasco JM. Postlaparoscopic small bowel obstruction.
Rethinking its management. Surg Endosc. 1998;12:10431045. SAI B. S. SAJJA, MD PANDURANGA R. YENUMULA, MD Department of Surgery Bronx Lebanon Hospital Center Bronx, New York
EDITORIAL COMMENT The postoperative fart is the best music to the surgeon’s ears . . . .” So, a few days ago you removed this patient’s perforated appendix, you gave him antibiotics for 2 to 3 days, and by today, you expected him to eat and go home. Instead, your patient lies in bed with a long face and a distended abdomen, vomiting bile from time to time. What is the problem? Is it “just” a “paralytic ileus,” or are we dealing with mechanical small bowel obstruction (SBO)? Ileus Ileus is a “normal” phenomenon after abdominal operations— it’s magnitude directly proportional to the magnitude of the CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
operation. Unlike mechanical intestinal obstruction, which involves a segment of bowel, postoperative ileus concerns the whole length of the gut, from the stomach to the rectum. Physiological postoperative ileus resolves gradually. The small bowel resumes activity almost immediately, followed, a day or so later, by the stomach, and then the colon, being the laziest, is the last to start moving. The magnitude of the postoperative ileus correlates to some extent with that of the operation performed and the specific underlying condition. Major dissections, prolonged intestinal displacement and exposure, denuded and inflamed peritoneum, and residual intraperitoneal or retroperitoneal pus or clots are associated with a prolonged ileus. Thus, for example, after simple appendectomy for nonperforated appendicitis, the ileus is almost nonexistent, whereas after a laparotomy for a ruptured abdominal aortic aneurysm (AAA), expect the ileus to be prolonged. Common postoperative factors, which can aggravate ileus, are the administration of opiates and electrolyte imbalance. Although the “physiological” postoperative ileus is “diffuse,” ileus caused by complications may be “local.” A classic example of a local ileus is a postoperative abscess, which may “paralyze” an adjacent segment of bowel. Early Postoperative Mechanical Intestinal Obstruction Early postoperative SBO is defined as one developing immediately after the operation or within 2 weeks. Two primary mechanisms are responsible: adhesions and internal hernia. Early post-laparotomy adhesions are immature, inflammatory, poor in collagen (thus, “soft”), and vascular. Such characteristics indicate that early adhesions may resolve spontaneously and that its surgical lysis may be difficult and “bloody.” Postoperative adhesions may be diffuse, involving the whole length of the small bowel in multiple sites, as occasionally seen after extensive lysis of adhesion for SBO. Localized obstructing adhesions may also develop at the operative site with the bowel adherent, for instance, to an exposed Marlex mesh or a raw peritoneal surface. The operation also may create new potential spaces into which the bowel can herniate to be obstructed, forming internal hernias. Typical examples are the partially closed pelvis after abdominoperineal resection, or the space behind an emerging colostomy. The narrower the opening into the space, the more likely is the bowel to be trapped. Diagnosis Failure of the patient to eat, pass flatus, or evacuate his bowel within 5 days after a laparotomy signifies a persistent ileus. The abdomen is usually distended and silent to auscultation. Plain abdominal x-ray typically discloses a significant gaseous distension of both the small bowel and the colon. The diagnosis of SBO in the recently operated abdomen is much subtler. Textbooks teach that on abdominal auscultation, ileus is silent and SBO is noisy; this may be theoretically true, but almost impossible to assess in the recently operated belly. If the patient has 293
TABLE 4. Clinical Considerations in EPSBO Primary operation
Question
Consideration
Laparotomy for SBO Abdomino-perineal resection Colostomy, ileostomy Laparoscopy Intestinal anastomosis
Was the obstructing point dealt with? Is the small bowel prolapsing into a pelvic space (CT)? Is the small bowel caught behind the stoma (contrast/CT)? Is the bowel caught in a trocar site (CT)? See below*
If If If If
not—consider an earlier re-operation yes—consider an earlier re-operation yes—consider an earlier operation yes—operate immediately
CT ⫽ Computed tomography; SBO ⫽ small bowel obstruction.
already passed flatus or defecated and then ceases to manifest these comforting features, SBO is the most likely diagnosis. The truth is that in most instances, the patient will improve spontaneously without you ever knowing whether it was a SBO or “just” an ileus. The natural tendency of the operating surgeon is to attribute the “failure to progress” to an ileus rather than to SBO and to procrastinate. Procrastination is not a good idea, however. A distended and noneating patient is prone to the iatrogenic hazards of the nasogastric tube, intravenous lines, parenteral nutrition, and bed rest. Be active and proceed with diagnostic steps in parallel to therapy. Management • Nasogastric tube, if not already in situ, has to be inserted to decompress the stomach, prevent aerophagia, relieve nausea and vomiting, and measure gastric residue. Carefully search and correct, if present, potential causes of prolonged ileus. • Opiates are the most common promoters of ileus; pain should be controlled but not excessively and not for too long. • Electrolyte imbalances are to be measured and corrected. • The possibility that an intra-abdominal complication is the cause of the ileus or SBO has to be considered and excluded. A hematoma, an abscess, an anastomotic leak, postoperative pancreatitis, and postoperative acalculus cholecystitis all can produce ileus or mimic SBO. • Significant hypoalbuminemia leads to generalized edema-involving the bowel too. Edematous and swollen bowel does not move well; this is called hypoalbuminemic entropathy and should be considered. Practically speaking, if on the fifth post-laparotomy day the patient still presents features of ileus/SBO, we recommend a plain abdominal x-ray to assess the gas pattern. If the latter suggests an ileus or SBO, a “Gastrografin challenge”2 may be useful in relieving both conditions. Gastrografin Challenge Gastrografin, a hyperosmolar agent that promotes intestinal “hurry,” plays 2 roles: diagnostic-prognostic and therapeutic. After the initial gastric decompression, 100 ml of Gastrografin are instilled through the nasogastric tube, which is then clamped for 2 hours. Four to 6 hours later, a simple plain abdominal x-ray is obtained. This is not a formal radiological study under fluoroscopy and not done by the radiologist, who 294
anyway, usually prefers to install barium. Presence of contrast in the large bowel proves that the obstruction is partial or that it is “ileus.” In most of these instances, the Gastrografin is passed per rectum. In partial SBO and ileus, Gastrografin is often therapeutic, as it expedites the resolution of the obstructing episode.1,2 On the other hand, failure of Gastrografin to reach the colon within 6 hours indicates a complete obstruction. The results of the study should be correlated with the whole clinical picture. Note that Gastrografin may pass across a chronic SB narrowing. Thus, for the obstructive episode to be considered as “resolved,” the abdominal symptoms and signs should disappear as well. When the clinical picture suggests one of the above-mentioned intra-abdominal causes of persistent ileus, an abdominal CT, combined with oral Gastrografin is indicated to pinpoint the problem and, at times, to guide treatment. When to Operate? As emphasized in the preceding section, intestinal strangulation almost never occurs in this situation and spontaneous resolution is common. Resolution of SBO, however, rarely occurs beyond the tenth postoperative day. In the absence of intra-or extra-abdominal causes for ileus, and when the “ileus” does not respond to the gastrografin challenge, the diagnosis is SBO. Do not rush to re-operate; treat conservatively while providing nutritional support. Lack of resolution beyond 10 to 14 days is an indication for re-laparotomy, which in itself may be difficult and hazardous because of the typical early dense and vascular adhesions cementing the bowel at many points. Special Problems When confronted with features of complete SBO demonstrated by the contrast study or CT, the surgeon should correlate these findings with information deriving from the primary operation (Table 4). Anastomotic Obstruction A bowel anastomosis at any level may cause early postoperative upper gastrointestinal, small bowel, or colonic obstruction. Faulty technique is usually the cause. A self-limiting “mini” anastomotic leak is often responsible but under-diagnosed. Diagnosis is reached with a contrast study or CT. Most such early CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
postoperative anastomotic obstructions are “soft” and edematous, resolving spontaneously within a week or 2.
REFERENCES 1. Assalia A, Schein M, Kopelman D, Hirshberg A, Hash-
Prevention Postoperative ileus and SBO are prevented by sound operative technique and attention to details. Gentle dissection and handling of tissues, careful hemostasis to avoid hematoma formation, leaving as little foreign bodies as possible, not denuding the peritoneum unnecessarily, not creating orifices for internal hernias, and not catching loops of bowel during abdominal closure, are self-explanatory essentials.
monai M. Therapeutic effect of oral Gastrografin in adhesive, partial small-bowel obstruction: a prospective randomized trial. Surgery. 1994;115:433-437. 2. Zer M, Kaznelson D, Feigenberg Z, Dintsman M. The
value of Gastrografin in the differential diagnosis of paralytic ileus versus mechanical intestinal obstruction: a critical review and report of two cases. Dis Colon Rectum. 1977;20:573-579.
Summary In a patient who does not move his bowels 5 days after laparotomy, exclude and treat causes of persistent ileus, treat SBO conservatively as long as indicated, think about specific causes of SBO (eg, herniation at a laparoscopic trocar site), and reoperate when necessary. In most instances, ileus/SBO will resolve spontaneously, and one never knows what was the cause. MOSHE SCHEIN, MD Department of Surgery Bronx Lebanon Hospital Center Bronx, New York
CURRENT SURGERY • Volume 59/Number 3 • May/June 2002
CORRECT ANSWERS TO THE QUIZ ON PAGE 2 What Is Your Diagnosis? Both 1 and 2 are possible. What Would You Do Now? 6. (The patient is on his third postoperative day and “permitted” to have an ileus.)
295