Chapter 5
Laparoscopic surgery in the treatment of colonic polyps
Q.A.J. Eijsbouts, G. Heuff, C. Sietses, S. Meijer, M.A. Cuesta
Br J Surg 1999; 86:505-8
Abstract
Background: Benign colonic polyps which are impossible to remove with the aid of the flexible colonoscope because of their size or location must be surgically removed.
Methods: Indications for surgery were the existence of a colonic adenomatous polyp that could not be resected by colonoscopy in a total of 20 patients, because of size or difficult location (n=18) or polyps in combination with diverticulitis (n=2). We describe the steps necessary to localize and remove the polyp through a small “assisted” incision in the abdominal wall after a standardized method of “dissection facilitated” laparoscopic surgery of the affected colonic segment.
Results: Between November 1991 and October 1997, 20 patients with benign colonic polyps were approached laparoscopically. In six patients the polyp was removed through a colotomy, in three patients through a limited resection (two ileocaecal and one limited sigmoid resection) and in eleven through a standard colectomy (four right, one left hemicolectomy, four sigmoid and two anterior resections) because of suspicion of cancer.
In only one of these cases the polyp could not be found during the laparoscopic intervention, which resulted in a second surgical conventional intervention. In four patients a carcinoma was diagnosed in the specimen.
Conclusion: Precise preoperative localization of the polyp and the use of the “dissection facilitated” laparoscopic colonic surgery makes removal of ‘benign’ colon polyps a clearly better alternative than the use of an open procedure.
Introduction
Standard treatment of benign colonic polyps is their resection by a diathermic wire loop. Large polyps (more than 2.5 cm) can be removed by colonoscopy if adequate visualization of the pedicle is possible and the head can be ensnared. Sessile polyps however [1], can be removed piecemeal but this technique is not advised for ulcerating polyps. The experience of the endoscopist determines the size and the nature of lesions one is willing to approach. Because of their difficult location or size some polyps are impossible to remove by flexible colonoscope and must be surgically removed [2]. Developments in laparoscopic colonic surgery have contributed to the application of this approach to the resection of colonic polyps [3-14].The laparoscopic approach has introduced two technical challenges; firstly the localization of the polyp and secondly its proper surgical extirpation. Depending on the shape of the polyp, its size and location, proper extirpation can be performed through a colotomy (pedunculated or small sessile polyps) or a limited colectomy (large sessile polyps) or an oncological resection in case of suspicion of carcinoma. In this paper we describe our experience with the laparoscopic removal of twenty ‘benign’ colonic polyps. Indications for surgery, operative localization and technique as well as results and complications are also dealt with.
Materials and methods
From November 1991 to October 1997, 129 laparoscopic colon interventions were performed for preoperatively diagnosed ‘benign’ colonic processes, twenty of them being colonic polyps which were unresectable by colonoscopy. Seventeen patients were diagnosed as having adenomatous polyps by biopsies taken during colonoscopy and in a further three patients, despite visualization, adequate control could not be obtained during the attempt to excise because of their difficult location.
Even though our policy was to perform laparoscopic resection after only colonoscopic localization, difficulties in finding a right-sided polyp in one patient resulted in our using a systematic barium enema in the last eleven patients in order to anatomically localize the polyps. In three of these patients the possibility of malignancy was suggested because of the imaging characteristics of the enema.
In all cases the preoperative decision to approach the processes as polyps and not as cancer was made on both the histological diagnosis of the biopsies and the colonoscopic aspect.
Reasons for referral to surgery were:
A) Difficult location (six caecal, four in the hepatic flexure and one in the transverse colon);
B) Size (one in descending colon, four in the sigmoid, and two in the proximal rectum);
C) Polyps in the sigmoid found after an initial episode of acute diverticulitis (two patients).
Operative technique
General laparoscopic technique
According to the preoperative location, the affected colonic segment was approached by the so-called laparoscopic “dissection facilitated” procedure.
In this procedure the entire affected colonic segment is mobilized by laparoscopy, exteriorized through a well placed small incision, subsequently resected and anastomosed [15]. For this procedure, we used a standard approach published elsewhere [16, 17]. Depending on the preoperative localization a complete mobilization of standard colonic segments (right colon, transverse colon, left colon, sigmoid and proximal rectum) with their corresponding mesentery was performed. If the exterior aspect of the corresponding segment of the colon showed changes typical of cancer (invasion of the process outside the serosa and rigidity), the process was approached as a carcinoma. Once the proper segment was dissected free we proceeded to exteriorize it through a well protected assisted periumbilical 7 cm incision. We used this approach for all parts of the colon except for polyps located in the sigmoid or proximal rectum for which a Pfannenstiel incision was preferred.
Specific laparoscopic technique
After exteriorization of the colon segment, evaluation of the polyp was performed by palpation. If the polyp felt completely soft and its size was less than 2.5 cm, resection was performed through a longitudinal colotomy through a tenia. We followed with submucosal injection of saline and subsequent radical extirpation by means of diathermia with a one centimeter margin. Frozen section determined the exact diagnosis and free margins. The colotomy was closed transversally in two layers. If the polyp felt soft but its size was more than 2.5 cm, it was resected by means of a limited colon resection followed by frozen section study. In the case of any suspicion (during the laparoscopic inspection or by palpation of the exteriorized colonic segment) of cancer (even in the top of the polyp) a standard laparoscopic oncological resection was performed.
If on exteriorization, the polyp could not be clearly palpated, intraoperative endoscopy was called for. A colonoscopy was used in three cases for finding polyps in the transverse, descending and sigmoid colon, and an endoluminal endoscopy (with the laparoscope and the corresponding cannula of 10 mm introduced through the appendicular basis) to localize a polyp in the hepatic flexure. In the endoluminal technique, intraluminal pressure should not exceed 8 mm Hg to prevent the risk of perforation [3].
Results
The surgical procedures are depicted in Table 1.
All twenty patients, thirteen men and seven women with a mean age of 63.2 years (45-83), were approached laparoscopically. In one patient with a polyp preoperatively localized in the coecum which could not be found after exteriorization of the right colon, we chose not to convert to laparotomy, but to postpone the removal until after a better localization procedure. After a colonoscopy and barium enema the patient underwent a conventional right hemicolectomy for a polyp localized distal to the hepatic flexure. Another nine polyps were localized in the right colon: exteriorization of the specimen was performed through either a right lower abdomen muscle splitting incision (two patients) or a periumbilical incision (seven patients). Three polyps were removed through a colotomy in the coecum, one by a colotomy in the splenic flexure, two by ileocaecal resection and the other three by means of a right hemicolectomy. One polyp was found in the transverse colon and was removed by colotomy. One polyp localized in the descending colon and suspected of being cancer was resected by a left hemicolectomy (the specimen being retrieved through a periumbilical incision).
|
Table 1. Laparoscopic surgical procedure (n=20) |
Table 2. Histological results performed (n=20) |
|
Right colon n Colotomy 3 Ileo-caecal resection 2 Right hemicolectomy 5 (1 open) Transverse colon n Colotomy 1 Descending colon n Left hemicolectomy 1 Sigmoid and rectum n Colotomy 1 Small resection 1 Sigmoid resection 4 Anterior resection 2 |
Right colon n Lipoma 1 Invaginated appendix stump + VA 1 TVA 4 VA 1 Hyperplastic polyp 1 Carcinoma 2 Transverse colon n TVA 1 Descending colon n Carcinoma 1 Sigmoid and rectum n TVA 6 Hyperplastic polyp 1 Carcinoma 1 TVA: tubovillous adenoma VA: villous adenoma |
Eight polyps were found in the sigmoid and proximal rectum. After mobilization in four patients the specimens were retrieved through a left lower abdominal muscle splitting incision and in the other four through a Pfannenstiel incision. One was removed through a colotomy, another through a limited sigmoid resection, four by means of a sigmoid resection (in two patients because of a concomitant diverticulitis) and in the last two patients by an anterior resection. With the exception of the patient who underwent a second surgical intervention, no conversions to laparotomy were performed in this series.
Histological results of the specimens are depicted in Table 2.
In four patients a carcinoma was found, Dukes B1 three times and B2 once. All resections were considered as radical. The remaining patients had either a tubular-villous adenoma (11x), villous adenoma (1x), hyperplastic polyps (2x), invaginated appendix stump with initial changes of adenomatous tissue (1x) or a large lipoma in the ascending colon (1x). The size range of the carcinomas was 3 to 6 cm and the adenomatous polyps varied from 1.7 cm to 5.5 cm. The two resected hyperplastic polyps were localized in the coecum (1.5 cm) and in the sigmoid (5 cm).
The mean postoperative hospital stay was five days with a range of 3-16 days. No major complications occurred in this series. One patient had a wound infection and another a urinary infection. Follow-up of the patients included outpatient clinic controls in which after one year a colonoscopy (with the exception of patients with hyperplastic polyps or lipoma) was performed. In two of twelve patients benign adenomatous polyps measuring 5 mm were found in the sigmoid colon and were extirpated. Colonoscopy will be repeated after one year. In the remainder of the patients it will be performed after three years.
Discussion
The standard treatment for colorectal polyps is colonoscopic removal using a wire loop [1]. This treatment has a low complication rate and it is currently performed on an outpatient basis. Pedunculated lesions are easier to remove than the sessile ones. Limitations for this treatment are the ability of the endoscopist to remove a large polyp (larger than 2.5 cm), or to extirpate a lesion in a difficult location such as in the hepatic flexure or coecum [1, 2]. In these cases the patients are sent to the surgeon for surgical removal. Once the patient has been referred, the question arises as how to resect the polyp, by colotomy or by resection (limited or oncological) and through which surgical approach. The risk of invasive carcinoma being harboured in a colorectal adenoma can be adequately predicted endoscopically on the basis of two variables: size and location. This risk increases with adenoma size irrespective of anatomical location. In small polyps (between 5 mm and 1.5 cm) the risk of cancer is 2% in the rectum and less than 1% in the rest of the colon. Between 1.6 and 2.5 cm, these percentages increase to 30 and 12%. If the size of the polyp is larger than 2.5 cm this will be 51 and 34% respectively [9].
These risk factors for invasive carcinoma will also influence our surgical strategy. After proper preoperative localization by colonoscopy and barium enema, complete laparoscopic mobilization of the corresponding colon segment and its mesentery will be performed. After exteriorization of the segment through a well placed incision (usually a periumbilical or Pfannenstiel incision), palpation will identify the polyp. In case of doubt, endoscopy performed by introducing a colonoscope in the case of a polyp located in the distal part of the colon or by endoluminal endoscopy using simply the laparoscope introduced with a cannula of 10 mm through the appendicular basis will help to select the adequate policy. Polyps less than 2.5 cm and appearing soft on palpation will be approached by a colotomy followed by frozen section. Soft polyps larger than 2.5 cm will be resected initially by a limited resection (and frozen section study) and lesions suspected for cancer approached as cancer and resected oncologically. The results of our series confirmed the adequacy of this strategy: all carcinomas had been suspected during the laparoscopic phase of the operation or during palpation of the exteriorized colonic segment. Twenty-one percent invasive carcinomas is in concordance with what is found in the literature for surgically removed polyps [9].
Several reports on laparoscopic colonic resections have a small percentage of patients in whom indication for surgery was polyps [6, 8]. Another researcher claims that benign colonic polyps formed one of the best indications for colonic laparoscopic surgery [7], and finally other reports described different laparoscopic approaches for polyps in a limited number of patients [3-5, 9-14]. In the case of inaccessible polyps, Smedh et al. [14], mobilized the corresponding colon segment by laparoscopy, gaining access for the flexible colonoscope. For colonoscopic extirpation of difficult or large polyps, Averbach et al. [13], used laparoscopy as an observational tool to ensure that the colonoscopist did not perforate the wall of the colon during their removal.
Peroperative localization methods, such as an India ink tattoo [18] injected one day before the operation, and laparoscopic ultrasonography of the colon have been used with good results. By laparotomy, Botoman et al., found the tattoo in 75% of the 14 marked patients. They advised using this technique in flat colon cancer and for previously snared malignant polyps which during the operation cannot be palpated. In our experience the major problem is not the localization of the polyp during the surgical procedure, but rather the adequate approach to excise it. A good preoperative localization procedure, such as a double contrast colon enema, followed by an adequate mobilization and exteriorization of the affected colonic segment will permit the surgeon to make a decision concerning a more or less extensive resection. Special problems are associated with polyps located in the sigmoid-rectal transition area and complicate the choice of approach. Transanal endoscopic microsurgery, according to Buess [19] is possible up to about 18 cm from the anus because beyond this point the abdominal cavity can be opened during the dissection. Therefore, polyps located higher up should be approached laparoscopically. To aid the decision, sigmoidoscopy should be repeated previous to intervention because the distance measured by the endoscopist is not always accurate. Nowadays the introduction of endostaplers through the Buess rectoscope permits the resection of small polyps (up to 2.5 cm) up to 15 cm from the anus [20].
It may be concluded that with a broad knowledge of the principles about the increasing possibility of polyps (by their size) to harbour an invasive carcinoma, a polyp that cannot be removed by colonoscopy (because of its size or location) should be approached by laparoscopy. Conservative or oncological resection will depend on palpation of the polyp and its size.
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