36 Unexpected Intraoperative Findings and Complex Preoperative Decisions

10.1055/b-0038-166170

36 Unexpected Intraoperative Findings and Complex Preoperative Decisions

David E. Beck

Abstract

Despite advances in preoperative evaluation, unexpected disease states or anatomic variations will be identified intraoperatively, which requires the surgeon to make important decisions rapidly. Challenging complex preoperative decisions as well as unusual or unexpected intraoperative findings are discussed with suggestions for managing them. Several of these were selected for their controversial nature. While not particularly uncommon, they continue to present a dilemma for the surgeon.

36.1 Introduction

The ever-expanding technology available to the practicing physician has greatly improved the identification of intra-abdominal pathology in advance of a laparotomy. This often leads to complex preoperative decisions. Nevertheless, from time to time surprises do arise with additional disease states or anatomic variations and the surgeon must make important decisions rapidly. This chapter highlights some complex preoperative decisions as well as unusual or unexpected findings and offers suggestions for managing them. We recognize that the management of many of these problems is controversial; in fact, that is precisely why these subjects have been selected. Although we are well aware that the list of surprises could extend almost without limit, we have chosen to focus on subjects that are not particularly uncommon yet present a dilemma to the surgeon. Suggested therapy may represent only a consensus of the authors.

The gynecologist or urologist often discovers large bowel pathology under one of the following circumstances: (1) during the operative treatment of established gynecologic pathology, (2) when acute or chronic pelvic sepsis is demonstrated as due to complications of large bowel disease, (3) when the true nature of an abdominal pelvic neoplasm is determined at laparotomy. Since bowel preparation may not have been performed in such situations, definitive treatment may result in higher postoperative morbidity than would result under ideal conditions. The dilemma involved is that the surgeon is faced with one of several challenging situations: (1) unprepared bowel, which may have an increased sepsis in colorectal operations; (2) established sepsis with the obvious concern of creating an anastomosis; or (3) possible catastrophic outcome if sepsis should ensue following an associated operation (e.g., as for an abdominal aortic aneurysm [AAA]). Some of the following case examples will be all too familiar to many readers.

36.1.1 Colorectal Carcinoma

During operations for colorectal cancer, intraoperative findings may be challenging.

36.1.2 Case 1: Carcinoma of Rectum and Unexpected Synchronous Colon Carcinoma

At laparotomy, a 72-year-old patient being operated on for carcinoma of the rectosigmoid is found to have a previously unsuspected mass in the hepatic flexure deemed to represent a synchronous carcinoma. There is no evidence of metastatic disease. What is the most appropriate operation?

With a patient having synchronous carcinomas, a number of options are open. The surgeon could proceed with the planned low anterior resection and assess the right colonic mass postoperatively through a barium enema or colonoscopic evaluation. Alternatively, the surgeon could allow recovery period of several weeks before a right hemicolectomy is performed. Both options are inappropriate.

The two preferred options are (1) to proceed immediately with a total abdominal colectomy and ileorectal anastomosis or (2) to perform two resections, the planned low anterior resection and a right hemicolectomy. There is no question that the first option is appealing because it rids the patient of both carcinomas through only one anastomosis. Furthermore, it might be best for a patient who already harbors two malignancies of the colon to be liberated from an organ with demonstrated propensity to neoplasia. The short rectal stump would make follow-up of the remaining bowel simple for both the patient and the surgeon. The risk of one anastomosis may be less than the risk of two anastomoses. For patients with carcinomas that are both located more proximally in the bowel (i.e., anywhere from the cecum to the proximal to middle sigmoid colon), this option would seem to be the treatment of choice. If synchronous carcinomas are located in an area of similar lymph node drainage, the respective hemicolectomy is indicated. For patients with malignancies involving different drainage areas in the lymphatic system of the colon, subtotal colectomy or total proctocolectomy and ileostomy (if the distal rectum is involved) can be performed.

There are several proponents of subtotal colectomy. ¹ ^, ² ^, ³ However, an overriding consideration, especially in the older patient, is the postoperative functional results. ⁴ Exactly how much distal bowel is necessary for an adequate reservoir is uncertain and will vary from patient to patient. Experience with patients with familial adenomatous polyposis suggests that an anastomosis performed at the level of the sacral promontory has resulted in an acceptable frequency of defecation. It must be noted that for the most part this experience has been accumulated in young individuals.

The patient in question is older, and the proposed anastomosis would need to be performed at a considerably lower level. Under these circumstances, it would be anticipated that functional results would not be good, and therefore we would lean toward a double resection (i.e., the planned low anterior resection and a concomitant right hemicolectomy at the same operation). With the use of repeated colonoscopy, little trouble would be encountered in following the residual colon for metachronous neoplasia.

36.1.3 Case 2: Carcinoma of Right Colon and Unexpected Hepatic Metastasis

Most large hepatic masses will be identified on the preoperative CT scan. However, small lesions may be missed. Two unexpected 1-cm masses are found at the edge of the right lobe of the liver during laparotomy for resection of a right colonic carcinoma. Preoperative CT scan was normal. What is the recommended management?

The philosophy of the management of patients with metastatic disease to the liver has changed dramatically in the past 20 years. The goal of therapy in any operation for malignancy is the removal of all detectable disease. In this situation, the operation would encompass both a right hemicolectomy and an excision of the two small masses.

If the lesions had been larger (an uncommon finding with preoperative scanning), a procedure of greater magnitude (e.g., a right hepatic lobectomy) may have been required. Prior to hepatic resection, it would be necessary to determine the extent of other metastatic disease, if present. It also would be appropriate to discuss with the patient the potential risks of a partial hepatic resection of this magnitude. In addition, current practice in many centers is to consider four courses of adjuvant chemotherapy prior to liver resection.

Even in the presence of metastatic disease in the liver, the primary colonic carcinoma should be removed because of the risk of later complications such as bleeding and obstruction. Liver lesions not resected should be biopsied to confirm the presence of metastatic disease. The evaluation and treatment of colorectal metastasis is discussed in Chapters 21 and 22. ⁵ ^, ⁶ ^, ⁷

36.1.4 Case 3: Carcinoma of Rectum with Incidental Cholelithiasis

A 79-year-old man is undergoing anterior resection with a low pelvic anastomosis for adenocarcinoma of the rectum located 9 cm from the dentate line. The liver is normal, but the gallbladder contains multiple stones. There is no clear-cut history of symptomatic gallbladder disease. Should the gallbladder be removed?

The decision of whether to proceed with cholecystectomy must take into account the added morbidity and mortality of this procedure, the risks of symptomatic gallbladder disease developing in the immediate or late postoperative period.

Most studies have emphasized that although complication rates range from 20 to 41% when cholecystectomy is added to another intra-abdominal procedure, complications specifically related to the cholecystectomy occur in less than 3% of these cases, and the mortality rate is not increased. ⁸ ^, ⁹ ^, ¹⁰ ^, ¹¹ ^, ¹² ^, ¹³ ^, ¹⁴ ^, ¹⁵ ^, ¹⁶ ^, ¹⁷ ^, ¹⁸ ^, ¹⁹ ^, ²⁰ ^, ²¹ ^, ²² ^, ²³ ^, ²⁴ ^, ²⁵ ^, ²⁶ All of this assumes, however, that the cholecystectomy is performed during a procedure that has gone well, that the patient is stable, and that the incision does not need to be significantly extended. The assumption is that the scope and magnitude of the operation are not significantly increased or that the operation was inordinately prolonged. Shennib et al, ²⁷ in a study of 25 patients who underwent simultaneous cholecystectomy and colectomy, concluded that the addition of cholecystectomy was safe when performed during the course of an elective colonic resection if the patient was stable. The authors do not recommend performing cholecystectomy during the course of emergency colectomy in an ill patient with an unprepared bowel.

It is possible that patients with cholelithiasis discovered incidentally at the time of another abdominal operation may be at greater risk for developing symptomatic gallbladder disease than similar individuals not undergoing operation. In one study, the risk of cholecystitis or symptomatic gallbladder disease developing within 6 months of operation was found to be as high as 70% among 23 patients with cholelithiasis who did not have incidental cholecystectomy during an abdominal operation. ²⁴ Acute cholecystitis developing in the immediate postoperative period in similar patients also has been noted. ²⁴ Whether this relationship is fortuitous in the above studies or whether it is related to postoperative mechanical or metabolic factors is unclear.

Overall, it does appear reasonable and appropriate to proceed with cholecystectomy in the patient described here if favorable conditions exist. This would mean that the anterior resection and anastomosis proceeded without complication, that the patient’s condition remained stable throughout the procedure, and that the gallbladder can be reached easily through the original incision. Usually, cholecystectomy is technically feasible from either vertical or transverse incisions as long as the initial incision is generous and the patient is not obese. If the incision needs to be significantly extended to achieve adequate exposure for cholecystectomy, the overall scope of the operation is being expanded and the possibility of having a significant increase in postoperative complications becomes a factor. In these circumstances, it is best to leave the gallbladder intact.

If the cholelithiasis was not known preoperatively, from a medicolegal point of view it appears safe to proceed with a previously unplanned cholecystectomy when unsuspected cholelithiasis is identified, since a surgeon is ordinarily protected by the legal doctrine of “extension of informed consent.” ²⁸ The low morbidity and negligible mortality when cholecystectomy is performed, along with the alternative risks of postoperative symptomatic gallbladder disease when cholecystectomy is not performed, reinforce the validity of an intraoperative decision to proceed with cholecystectomy. Nevertheless, since this does constitute removal of an organ without the patient’s prior consent, it is especially important that the cholecystectomy be performed only under favorable conditions without increasing the magnitude of the operation. Legally, the safest course is to discuss the possibility of cholecystectomy or removal of other tissues with the patient at the time that consent for colectomy is obtained.

36.1.5 Case 4: Carcinoma of Rectum with Invasion of Urinary Bladder

An otherwise healthy 56-year-old man is scheduled to undergo a low anterior resection of the rectum. Preoperative imaging demonstrates that the carcinoma invades the base of the bladder and the prostate. ²⁹ ^, ³⁰ ^, ³¹ ^, ³² ^, ³³ ^, ³⁴ ^, ³⁵ ^, ³⁶ ^, ³⁷ There is no evidence of distal spread. Should a pelvic exenteration be performed?

The recommendations made here are what we believe to be in the best interest of the patient. However, following them may result in procedures being performed without the patient’s fully informed consent. This discussion is not intended to cover that legal aspect of the problem.

Pelvic exenteration for colorectal carcinoma involves en bloc removal of the colon and/or anorectum, the bladder and distal ureters with creation of an ileal conduit, a pelvic lymph node dissection, and removal of internal reproductive organs as indicated. It is a formidable procedure with high morbidity and mortality rates. A review of the literature by Eckhauser et al ³⁸ showed a mortality rate of 12%. In a large series of pelvic exenterations for colorectal, gynecologic, and urologic diseases reported by Jakowatz et al, ²⁹ there was a major complication rate of 49%, including gastrointestinal fistulas or obstruction, urinary tract fistulas, infection or obstruction, wound dehiscence, and/or hemorrhages. The complications rate was highest (67%) when patients received preoperative radiation and lowest (26%) when radiation was not given. However, the operative mortality rate was only 2.9%. Other reports support the justification of pelvic exenteration or en bloc excision of a T4 lesion, if the procedure can be performed with an intention of cure. ³⁰ ^, ³¹ ^, ³² ^, ³³

There are two major justifications for aggressive surgical treatment of patients with locally advanced primary and recurrent rectal carcinoma in the absence of gross distant metastases. First, many of these patients will die with catastrophic symptomatic consequences of uncontrolled pelvic carcinoma, primarily pain and tenesmus. Symptoms are only temporarily abated with radiation therapy alone. Second, autopsy studies suggest that 25 to 50% of such patients have carcinoma limited to the pelvis at the time of death. Hence, aggressive efforts at local control may not only avoid painful recurrence in such patients but also disease-free and overall survival may be improved. ³⁴

Colorectal carcinoma with direct invasion into the bladder but without distant metastases is uncommon, accounting for only 5% of cases. ³⁵ This type of lesion cannot be cured by nonoperative management such as chemotherapy or radiation therapy. Preoperative radiation for a clinically resectable lesion will not change the extent of the resection, ³⁶ and it may only increase the complication rate. ²⁹ When patients are properly selected, the 5-year survival rate can be expected to be 45 to 50%. ³⁵ ^, ³⁷ Ideally, the lesion should be limited locally without lymph node metastases. En bloc resection of the rectum and the adjacent involved organs was performed in 65 patients in a series reported by Orkin et al. ³⁷ Of those patients, 26% underwent a cystectomy. There were no perioperative deaths. Postoperative complications developed in 20% of patients, and the overall 5-year survival rate was 52%. Talamonti et al ³⁹ reviewed the records of 70 patients who underwent resection of a carcinoma of the colon and rectum with en bloc total cystectomy (36 patients) or partial cystectomy (34 patients) because of malignancy directly extending into the urinary bladder. Sixty-four patients with negative resection margins had a median survival of 34 months and a 5-year actuarial survival rate of 51.8%. In contrast, the median survival period for six patients who had positive margins was 11 months, with no survivors at 5 years.

The only hope for cure in colorectal carcinoma with invasion into the bladder is to perform pelvic exenteration. This is an extensive operation with potentially high morbidity, mortality, and prolonged postoperative recovery. In properly selected patients, the operation is worthwhile in terms of long-term survival and symptomatic relief. Patients with distant metastases should not be considered for pelvic exenteration.

At the time of exploration, the surgeon must accurately establish the extent of pelvic disease and the surgeon’s ability to remove it. Actual histologic invasion of adjacent structures can be very difficult to differentiate from inflammatory reaction without pathologic confirmation. Complete excision of the neoplasm with a portion or all of any apparently involved organs appears to result in the best possibility of complete excision and thus cure. A team approach consisting of a colorectal surgeon, a gynecologic surgeon, and a urologic surgeon helps achieve optimal results. ³⁷

The bulkiness of the lesion should not deter surgeons. Size and local extension do not correlate with long-term survival. The most important predictors of survival are lymph node status and involvement of the resection margins. In fact, the overall survival in patients with T4 carcinomas who underwent radical resection is not significantly different from that in those with T3 carcinomas, even in N1 stages. ³²

Armed with this information, what should the surgeon do for the patient? Ideally, a discussion is held with the patient preoperatively, but since the intraoperative findings were a surprise, this cannot be done. The options are to proceed with an exenteration or close the abdomen and discuss the recommendation with the patient. It is technically easier to proceed at the original operation because repeat operations are more difficult. Most often, a portion of the mobilization has already been accomplished, and it is quite possible that the best technical operation can be accomplished at this time. However, because of the magnitude of the procedure, the potential high complication rate, and the lifestyle alteration for the patient, we would favor aborting the procedure and discussing the advantages of a pelvic exenteration with the patient.

36.1.6 Case 5: Concomitant Carcinoma of Rectum and Abdominal Aortic Aneurysm

A 75-year-old man is scheduled to undergo low anterior resection of the rectum for a carcinoma. Preoperative scanning reveals a 6-cm AAA. What is the appropriate management?

The occurrence of synchronous colorectal carcinoma and AAA is uncommon. At the Mayo Clinic from 1975 to 1986, approximately 3,500 patients with AAA underwent repair, but only 17 patients were found to have a simultaneous colorectal carcinoma. ⁴⁰ Most lesions were discovered before the operation and thus the management could be planned. More recently, Baxter et al ⁴¹ reviewed 435 Mayo Clinic patients with a history of colorectal carcinoma and AAA, of which 83 patients had concomitant AAA and colorectal carcinoma. In 64 patients, the colorectal carcinoma was treated first, and 44 of these patients had an AAA < 5 cm in diameter (average = 3.8 cm). No AAA ruptured in the postoperative period. Median delay in colorectal carcinoma surgery from diagnosis was 4 days. There were 20 patients with AAA of 5 cm or greater (average = 5.4 cm) who were treated for colorectal carcinoma first. In two of these patients (with AAA sized 5 and 6.4 cm), the AAA ruptured in the early postoperative period. Median delay in colorectal carcinoma resection was 8 days. There were 12 patients who had both an AAA and colorectal carcinoma treated at the same time. The average size of the AAA was 6.4 cm. Median delay from colorectal carcinoma diagnosis to resection was 15 days. No documented cases of graft infection occurred in this group; median follow-up was 3.2 years. There were seven patients who underwent AAA repair before resection of their colorectal carcinoma; in two patients, colorectal carcinoma was found at the time of resection. The average size of the AAA was 6 cm and median delay to treatment of colorectal carcinoma was 122 days, a statistically significantly longer delay than in the other two groups. They concluded that in patients with colorectal carcinoma and AAA of 5 cm or more, treatment of colorectal carcinoma first might result in life-threatening rupture, whereas treatment of the AAA first might significantly delay treatment of the colorectal carcinoma. Concomitant treatment seems to be a safe alternative. If anatomically suitable, the AAA may be considered for endovascular repair, followed by a staged colon resection. The presence of an AAA less than 5 cm does not affect colorectal carcinoma treatment. Herald et al ⁴² also described the use of endovascular placement of a graft for the treatment of AAA in association with rectal carcinoma. Minimally invasive endovascular repair is currently the procedure of choice. ⁴³ ^, ⁴⁴

In general, it has been recommended to treat the lesion that causes symptoms first, with an option to manage the second lesion at the same time or at a later date. ⁴⁵ Frequently, however, the patients are generally free of symptoms, and one lesion is discovered incidentally at the elective resection of the other. What should be done? If neither symptoms nor aneurysm size establishes priority, the relative indolent course of colon carcinoma favors aneurysm repair with colectomy in 2 to 4 weeks. ⁴⁰

Historically, the advantages of concomitant resections of colorectal carcinoma and AAA are avoidance of a second operation and elimination of the possibility of a ruptured AAA postoperatively if left untreated. The major risk of this approach is a possible aortic graft infection, which can be life threatening. The risk of ruptured AAA after laparotomy is real. ⁴⁰ ^, ⁴⁶ Some attribute this to the increased activity of the proteolytic enzymes collagenase and elastase, ⁴⁵ ^, ⁴⁶ ^, ⁴⁷ ^, ⁴⁸ although this is only speculation. In a series by Nora et al, ⁴⁰ eight patients had colorectal resection without resection of the AAA. Three patients died from complications of the aneurysm, including two ruptured aneurysms and one thrombotic aneurysm. The remaining five patients also died, four from disseminated carcinoma, with death occurring 6, 12, 18, and 48 months later; the other patient died from sepsis 36 hours postoperatively. It appears that for longterm survival both lesions must be resected aggressively. ⁴⁰ The size of the aneurysm plays an important role in the decision-making process. It is generally agreed that an AAA > 7 cm poses a risk of rupture in the near future and tends to rupture soon after colonic resection. ⁴⁹ Therefore, such an aneurysm should be resected first, unless the colorectal carcinoma is obstructing. Velanovich and Andersen ⁴⁵ recommended that when both lesions are asymptomatic and the aneurysm is 4 to 5 cm in diameter, it should be resected first, if the colorectal carcinoma has a less than 5% chance of obstruction or perforation, as is found in noncircumferential lesions. When the aneurysm is greater than 5 cm, it should be resected first if the carcinoma has a less than 22% chance of obstructing or perforating, as with circumferential lesions. Simultaneous resection should be considered for patients with aneurysms greater than 5 cm and carcinomas with a greater than 75 to 80% chance of obstruction or perforation, provided the dual procedures can be performed with a less than 10% operative mortality and less than 50% complication rate. If it is deemed that there is an impending obstruction by the carcinoma, both the aneurysm and the carcinoma should be resected simultaneously. ⁵⁰ The AAA should be resected first and the retroperitoneum closed, with interposition of omentum between the graft and the peritoneum before resection of the colon and rectum to minimize the risk of graft infection. An elective simultaneous resection of AAA and a right colectomy can be safely performed. The risk of anastomotic leak is higher for a left colectomy. For a low anterior resection, unless the procedure is easy, a complementary loop ileostomy should be considered, or a colostomy and Hartmann’s pouch procedure should be performed.

A 5-cm-diameter AAA has a 4.1% annual risk of rupture if left untreated, and this risk increases exponentially with increasing aneurysm diameter so that a 7-cm AAA has a 19% yearly risk of rupture. ⁵¹ In situations where the carcinoma shows no symptoms of obstruction and the aneurysm is also asymptomatic and less than 6 cm in diameter, it has traditionally been taught that the aneurysm should be resected first because of the risk of postlaparotomy rupture of the aneurysm, which has been reported to be as high as 33.8%. ⁴⁵

The surgeon must be certain that the two ends of bowel have good blood supply. After sacrificing the inferior mesenteric artery, there is usually enough blood supply from the marginal artery of Drummond as well as branches from the iliac arteries. It has been shown that colonic ischemia is usually the result of perioperative low cardiac output and the use of alpha-adrenergic vasopressive agents. ⁵² ^, ⁵³ In this situation, an anastomosis should not be performed.

In the patient with a small AAA, the carcinoma should be resected first and the AAA should be resected at a later date.

The ability to perform minimally invasive endovascular aortic repair has largely eliminated the above discussion. ⁴³ ^, ⁴⁴ Larger or systematic aneurysms are percutaneously repaired and a colectomy can follow in short period.

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