| | A prospective evaluation of anorectal function after total mesorectal excision in patients with a rectal carcinoma☆☆☆Accepted 19 June 2002. Abstract Background. Rectum resection with total mesorectal excision (TME) and neorectal anastomosis often compromises anorectal function. Insight into the underlying mechanisms is lacking. Therefore, a prospective study was designed to investigate the relationship between clinical and functional outcomes preoperatively and postoperatively. Methods. Eleven patients with rectal cancer were examined before and 4 and 12 months after surgery and compared with 11 healthy volunteers (HVs). Anorectal (neorectal) function was examined by clinical outcome questionnaire, anal manometry, rectal compliance, and sensation. Six HVs also underwent barostat measurements in the sigmoid colon. Results. Clinical parameters of soiling and passive incontinence (loss of stool without sensation) increased significantly until 12 months postoperatively, whereas urgency and tenesmus increased temporarily, returning to preoperative values at 12 months. In anorectal measurements, anal sphincter function was grossly preserved; however, rectal-anal inhibitory reflex (RAIR) was decreased at 4 months but recovered after 1 year. Neorectal compliance was similar to that of HV sigmoid, increasing slightly after 12 months but still significantly lower than that of normal rectum. Neorectal sensation to pressure distention was similar to that of normal rectum, however accompanied by smaller volumes. Neorectal distention induced contractions of large amplitude at 4 months, returning to normal after 12 months. Conclusions. Our results suggest that the transient increase in urgency and tenesmus after surgery results from a temporary increase in neorectal “irritability” accompanied by some adaptation of compliance in time. In contrast, episodes of incontinence and soiling are increased after 1 year most likely because of reduced neorectal capacity and RAIR recovery in the presence of a low basal anal sphincter pressure. (Surgery 2003;133:56-65.)
Anal sphincter function, rectal reservoir capacity, and the ability to differentiate between rectal sensations of gas, liquid, and solid stool are important features in maintaining fecal continence. Patients who have to undergo surgery for rectal carcinoma are at risk for reduced postoperative anorectal function. Improved surgical techniques, such as total mesorectal excision (TME), which advocates rectal mobilization via sharp dissection under direct vision along the parietal pelvic fascia, have been reported to result in lower recurrence rates and probably better 5-year survival.1, 2 A good long-term functional outcome is therefore becoming increasingly important.3
Yet, functional results remain suboptimal up to 1 year after surgery even in recent reports, as illustrated by increased defecation frequencies, soiling incidence, and even, although less frequently, incontinence of liquid or solid stools.4, 5, 6, 7, 8, 9 There is an ongoing debate about the pathophysiology of this disturbed functional outcome. Explanations for impaired anorectal function include decreased internal and external anal sphincter function due to direct damage or injury of the nervous supply or anal sphincter,4, 5, 7, 9, 10, 11, 12, 13 the level of the coloanal anastomosis,14, 15 impaired neorectal capacity or compliance,4, 7, 9, 14 and the loss of rectal sensation.16, 17, 18 The substantial number of studies on anal sphincter function, however, give no absolute clarification for the impaired anorectal function. Therefore, more emphasis must be put on the impact of impaired neorectal capacity, compliance, and the change in rectal sensation and motility, considering that the distensibility characteristics of sigmoid or descending colon used for construction of a neorectum are very different from those of a normal rectum.
At present, only a few studies4, 7, 14 have prospectively evaluated rectal function before and up to 1 year after surgery. Although manometry and neorectal compliance measurements were performed in all studies, they only correlated the outcome to bowel frequency4, 14 or to an overall score of clinical bowel function.4, 7 A comparison of neorectal compliance and sensation with that of a healthy volunteer sigmoid or descending colon (the section of colon that is used for neorectal construction) has not been performed. Moreover, a combination of early and late postoperative assessment to evaluate changes in time has not been performed. Therefore, a prospective study was designed to evaluate the effects of TME on anal sphincter and rectal function, and to study the degree of adaptation in time. In addition, changes in functional outcome at different time points were evaluated in relation to the clinical outcome to gain more insight into the underlying pathophysiologic mechanisms in these patients.
Material and methods  Study protocol Patients and healthy volunteers answered a questionnaire regarding their anorectal function and were examined by means of anorectal manometry, rectal and anal mucosal electrosensitivity testing, pudendal nerve terminal motor latency (PNTML) time, and neorectal compliance and visceral sensation measurements. In TME patients, anorectal function was assessed 1 week before, and 4 and 12 months after surgery. All subjects underwent bowel preparation by means of a sodium phosphate enema either at home or at least 1 1/2 hours before onset of the anorectal function measurements. Each subject answered a questionnaire to assess defecation frequency during daytime or nighttime, stool consistency, blood loss per anum, the ability to differentiate between flatus and stools, soiling during daytime and nighttime, anal incontinence score,19 urgency to defecate, episodes of passive incontinence, loss of a large quantity of feces (more than just “soiling” or “spotting”), need to wear pads, sensation of incomplete evacuation, and tenesmus. The answers were characterized as never, occasional (less than once a week), frequent (at least once a week), or daily occurrence. The anal incontinence score as described by Pescatori et al,19 even though not yet validated, gives an indication of the type of incontinence, ie, incontinent for flatus, liquid, or solid stools, and the frequency, ranging from never to every day. Subjects were placed in left lateral position for anorectal manometry. After insertion of the catheter the recordings were allowed to stabilize for 15 minutes, after which the mean value of the resting pressure was measured for 2 minutes. Hereafter the subjects were instructed to maximally squeeze on 3 occasions. The terminal inflatable balloon was inflated with increasing volumes (10 to 50 mL) to assess a neorectal-anal inhibitory reflex (RAIR). RAIR was defined as a reduction of internal anal sphincter pressure from baseline of at least 10 mm Hg of 5 seconds' duration.20 After removal of the manometric assembly, a ring electrode was inserted into the rectum approximately 10 cm above the anal verge to measure rectal mucosal electrosensitivity. A small pulsating electric current generated by a computer-controlled stimulator (Dantec Keypoint, Skovlunde, Denmark) was applied and increased until subjects reported some rectal/abdominal sensation. The amperage of first sensation was recorded on 3 occasions. The electrode was then positioned into the mid-anal canal, and the same measurements were done to estimate the anal mucosal sensation threshold. After these measurements, the barostat bag was inserted into the neorectum. To prevent curling up of the bag and kinking of the catheter, the folded bag was placed into a nonflexible tube. After insertion of approximately 20 cm, the overtube was withdrawn. The bag was slowly inflated with 80 to 125 mL to allow adequate unfolding and was then drawn back against the pelvic floor or in postoperative patients until just above the anastomosis (Fig 1, A).
The catheter was secured with tape to maintain its position. A recovery period of 15 minutes was allowed after which minimal distention pressure (MDP) was determined. Thereafter, an intermittent isobaric pressure controlled distention protocol (pressure steps of 3 mm Hg lasting 2 minutes) was started. Subjects were asked at the onset of the distention, at 30 seconds, and at 60 seconds to score their sensation on a scale varying from (1) nothing, (2) first sensation, (3) a light desire to defecate, (4) desire to defecate, (5) urgent desire to defecate, to (6) intolerable discomfort. The experiment was stopped when subjects experienced intolerable discomfort or when 50 mm Hg was reached. After the barostat study, 3 reproducible PNTML recordings were taken from each side. All healthy volunteers underwent the same measurements. However, in 6 healthy volunteers, both the rectum and the sigmoid (at 30 to 35 cm from the anal verge, which is normally used for coloanal anastomosis) were examined by using the same intermittent isobaric pressure-controlled distention protocol. The barostat bag was positioned in the sigmoid colon by means of a sigmoidoscopy (Fig 1, B.) The Hospital Ethics Committee approved the protocol, and informed consent was obtained from all patients and healthy volunteers. Equipment Anorectal manometry Anorectal manometry was recorded by using a multilumen 14.5-cm long, water-perfused sleeve catheter assembly, with a 4-cm long sleeve and 5 radially distributed side holes, positioned at 1, 2, 3, 4, and 6.5 cm and a terminal inflatable balloon at 8.5 cm from the anal verge (Dentsleeve Pty Ltd, Parkside, Australia). Each side hole was perfused with degassed water at a rate of 0.3 mL/min, and intraluminal pressures were sensed by external transducers, connected to a polygraph (Synetics Medical, Stockholm, Sweden), and monitored and analyzed with commercially available software (Polygram for Windows; Synetics Medical). Mucosal electrosensitivity/PNTML A 1-cm long bipolar ring electrode (Dantec 21L10; Dantec Medical, Skovlunde, Denmark) mounted on a Foley urine catheter was used to measure the rectal and anal mucosal electrosensitivity.21, 22 For measuring the PNTML time, a St Mark's pudendal electrode (Dantec Medical) was used.23 Rectal barostat study To measure compliance and rectal sensitivity, an electronic barostat (Synetics Medical) was used. There was a fixed pressure limit that automatically triggered balloon deflation for pressures above 55 mm Hg. A noncompliant polyethylene bag was hermetically fastened to a double-lumen 12F Salem polyvinyl tube (Sherwood Medical, St Louis, Mo) and connected to the barostat. The maximum capacity of the bag was 350 mL and had a maximal diameter of 11 cm and a length of 14 cm. The balloon was inflated up to 20 mm Hg before and after completion of the experiment to rule out any leakage of air. Data analysis Two-way analyses of variance were used for comparison of preoperative and postoperative data, as well as for comparison of healthy volunteers with patients. Maximum squeeze pressure and mucosal electrosensitivity threshold values were reported as the mean of 3 measurements. Results were presented as mean ± standard error of mean (SEM). Nonparametric tests were used in case of ordinal data, and proportions of events were compared by means of chi-square tests; values less than .05 were considered statistically significant. Phasic volume-pressure curves for compliance calculation were obtained from mean volume values reached during each 120-second pressure step. The volume-pressure curves were described with the following equation, V = A (1 − e−kp), where V is the volume, A is the maximum volume, k is an expansion constant, and p is pressure. Compliance is defined as dV/dp and computed at V1/2, which is half the maximum volume. A mixed nonlinear model24 was used to estimate the mean compliance curves for patients (preoperatively and postoperatively) and volunteers by means of the restricted maximum likelihood method. In addition, comparisons of the fixed effects estimations of the fitted compliance curves in time and between patients and volunteers were performed by using a Wald test on fixed effects. Overall goodness of fit was assessed by the Bayesian Information Criterion.25 The influence of surgery on the perception of the neorectal sensation was evaluated by comparing the percentage of patients in whom a specific sensation was elicited at a certain pressure level. The cumulative percentages of patients at 4 and 12 months and the volunteers measured in either the rectum or the sigmoid colon were analyzed with Kaplan-Meier analysis, and differences were compared by log-rank test. This analysis method was chosen because not every barostat procedure was terminated by the sensation of intolerable discomfort, and because measurements with the barostat bag were ceased at the maximum distention pressure of 50 mm Hg. Kaplan-Meier analysis enabled us to take every measurement into account even if a certain sensation was not induced. The measurement was censored at the highest pressure at which this sensation could not be induced. Results Fifteen patients were enrolled in the study protocol. Eleven patients were reevaluated at 4 and 12 months after surgery (mean age, 66 ± 3.6 years). Four patients did not complete the study protocol because of various reasons, and their results were excluded from the final analysis. Two patients withdrew themselves from the study because the investigations were regarded as too strenuous. In 1 patient it was decided intraoperatively to perform an abdominoperineal resection, and the fourth patient died of septic complications. None of the patients developed distant metastasis or local recurrence at the 1-year follow-up, and none received adjuvant radiotherapy or chemotherapy. No complications were encountered in any of the studies. The durations of the experiments did not exceed 4 hours. All patients underwent a TME and a stapled coloanal anastomosis [mean anastomotic height, 4 cm (± 0.7 cm)]. Surgery was performed according to the TME principles,26, 27 a sharp dissection of the mesorectum with its surrounding fascia. Intestinal continuity thereafter was restored by a double-stapled coloanal anastomosis. No anal pull-through procedure with a hand-sewn anastomosis has been performed. None had a colon pouch constructed. There was no tumor invasion into the anal canal, and all resection margins were free. The 11 healthy volunteers (mean age, 60 ± 2.9 years) were recruited by advertisement. None had a history of an acute or chronic illness or abdominal surgery. Clinical details of all subjects are shown in Table I. Clinical characteristics All but one patient presented with persistent blood loss per anum as principal symptom (Table II).
| | |  | | Healthy volunteers | Patients preoperatively | Patients 4 mo postoperatively | Patients 12 mo postoperatively | |
|---|
| Defecation frequency/day, median (range) | 1 (1-3) | 1.5 (1-9) | 3.5† (2-8) | 3.5† (1-6.5) | |
| Defecation frequency/night, median (range) | 0 | 0 | 0 (0-1.5) | 0 (0-1.5) | |
| Blood loss per anum, % patients (% every day) | 0 | 91 (45) | 0* | 0* | |
| Ability to differentiate flatus from stools, % patients (% every day) | 100 | 82 | 91 | 82 | |
| Soiling during daytime, % patients (% every day) | 9 (0) | 45 (9) | 73† (9) | 73† (18) | |
| Soiling during nighttime, % patients (% every day) | 0 | 0 | 27*† (9) | 45*† (18) | |
| Anal incontinence score,‡ median (range) | 0 (0-2) | 3† (0-5) | 2.5† (0-5) | 4† (0-5) | |
| Urgency of defecation, % patients (% every day) | 0 | 37 (9) | 46† (9) | 18 (0) | |
| Episodes with passive incontinence, % patients (% every day) | 0 | 9 (0) | 18 (0) | 46*† (0) | |
| Loss of large quantities, % patients (% every day) | 0 | 0 | 9 (0) | 9 (0) | |
| Need to wear a pad, % patients (% day and night) | 0 | 36 (0) | 64† (55) | 73† (27) | |
| Sensation of incomplete defecation, % patients (% every day) | 27 (0) | 55 (18) | 64 (18) | 45 (9) | |
| Tenesmus, % patients (% every day) | 9 (0) | 82† (27) | 55† (0) | 36 (0) | |
| *Significantly different (P < .05) from patients preoperatively. †Significantly different (P < .05) from healthy volunteers. ‡As described by Pescatori et al.19 | | | | |
Forty-five percent of all patients experienced soiling at least once a month, which is in agreement with the anal incontinence score of 3. Before surgery, approximately one-third of the patients reported urgency, and more than one-half of the patients had tenesmus and sensation of incomplete defecation. Postoperatively, the percentage of patients with soiling at night and with episodes of passive incontinence (at least once a month) increased significantly after 4 and 12 months. The defecation frequency during day, and the percentages of patients with soiling during the day and of patients with the need for pads showed an increase (although not significant) 4 months after surgery, and remained elevated 12 months postoperatively. In contrast, the percentages of patients with urgency, tenesmus, and sensation of incomplete defecation showed an initial increase after 4 months but decreased after 12 months to values that were lower than preoperatively. Finally, there were no significant changes in defecation frequency during night, stool consistency, the ability to differentiate between flatus and feces, anal incontinence score, and the percentage of patients with loss of large fecal quantities. Manometry, mucosal sensitivity, and PNTML outcome The results of the anal manometry are shown in Table III.
Preoperative resting and squeezing pressures of patients were significantly lower than those of healthy volunteers. Postoperatively, there was no significant decrease in either the resting pressure or the maximum squeezing pressure in comparison to preoperative values. | | | | | Patients | |
|---|
| Parameters (mean ± SEM) | Healthy volunteers | Preoperatively | 4 Mo postoperatively | 12 Mo postoperatively | |
|---|
| Resting pressure (mm Hg) | 75* ± 6 | 56 ± 8 | 35 ± 6 | 42 ± 7 | |
| Maximum squeezing pressure (mm Hg) | 196* ± 20 | 140 ± 16 | 118 ± 18 | 131 ± 18 | |
| RAIR† | 100% | 100% | 36%‡ | 82% | |
| Anal mucosal electrosensitivity (mAmp) | 5 ± 1 | 8 ± 1 | 7 ± 1 | 6 ± 1 | |
| Rectal mucosal electrosensitivity (mAmp) | 22 ± 4 | 27 ± 4 | 35 ± 7 | 30 ± 4 | |
| PNTML (ms) | | | | | |
|  Left | 2.0 ± 0.1 | 2.5 ± 0.1 | | 2.2 ± 0.1 | |
| Right | 2.2 ± 0.1 | 2.2 ± 0.1 | | 2.2 ± 0.1 | |
| *Differs (P < .05, ANOVA) from patients. †Present in healthy volunteers or patients. ‡Differs (P < .05, chi-square test) from patients preoperatively and 12 months postoperatively and healthy volunteers. | | | | |
The RAIR was present in all patients preoperatively as well as in all healthy volunteers. The presence of RAIR was significantly decreased to 36% at 4 months postoperatively but recovered to 81% after 12 months. Remarkably, during the RAIR assessment strong neorectal contractions, with pressures up to 321 mm Hg (mean, 84 ± 31 mm Hg; RAIR induced with 40 mL), were seen in patients 4 months postoperatively. These contractions decreased 1 year postoperatively (Table IV).
| | | | | Healthy volunteers | Patients | |
|---|
| | Rectum | Sigmoid | Preoperatively | 4 Mo postoperatively | 12 Mo postoperatively | |
|---|
| Compliance (mL/mm Hg) (mean ± SEM) | 9 ± 1 | 5* ± 1 | 9 ± 1 | 4* ± 1 | 6*† ± 1 | |
| Neorectal contractions during RAIR (mm Hg)(mean ± SEM) | 14 ± 5 | | 14 ± 4 | 84 ± 31 | 18 ± 4 | |
| Neorectal contractions during barostat distention (mL) (mean ± SEM) | 24 ± 6 | | 10 ± 4 | 42* ± 10 | 21† ± 8 | |
| Median pressures inducing | | | | | | |
| First sensation (mm Hg) (range) | 3 (0-9) | 4.5 (0-12) | 6 (0-12) | 3 (0-9) | 3 (0-15) | |
| Desire to defecate (mm Hg) (range) | 9 (6-50) | 36‡ (24-50) | 12 (3-30) | 9 (3-50) | 18 (3-50) | |
| Discomfort (mm Hg) (range) | 33 (18-50) | >50‡ | 21 (6-50) | 30 (9-50) | 36 (15-50) | |
| Median volumes inducing | | | | | | |
| First sensation (mL) (range) | 56 (27-93) | 34 (15-50) | 43 (14-68) | 40 (2-101) | 39 (6-109) | |
| Desire to defecate (mL) (range) | 152 (86-218) | 95§ (86-111) | 147 (75-215) | 57* (28-157) | 119† (30-199) | |
| Discomfort (mL) (range) | 222 (201-251) | | | 197 (119-286) | 102* (32-231) | 139§ (73-220) | |
| *Differs (P < .05, ANOVA) from patients preoperatively and healthy volunteers' rectum. †Differs (P < .05, ANOVA) from patients 4 months postoperatively. ‡Differs (P < .05, log-rank test) from patients' rectum and neorectum and healthy volunteers' rectum. §Differs (P < .05, ANOVA) from healthy volunteers' rectum. | | | | |
Preoperative anal and rectal mucosal sensitivity and PNTML data of patients did not differ from those of healthy volunteers. There were also no postoperative changes in both mucosal sensitivity and PNTML data (Table III). No data are given for PNTML data 4 months postoperatively because this examination was experienced as too strenuous by 8 patients. Neorectal and sigmoid colon compliance Mean compliance curves for patients (preoperatively and postoperatively) and volunteers are shown in Fig 2.
The preoperative rectal compliance in patients ( Table IV) was not different from that of healthy volunteers' rectum (8.9 ± 0.8 vs 9.3 ± 0.8 mL/mm Hg, respectively), but both were significantly higher than the postoperative patients' neorectal compliance (4 months: 4.4 ± 0.8 mL/mm Hg, 12 months: 5.5 ± 0.8 mL/mm Hg). The healthy volunteers' sigmoid colon compliance (4.9 ± 0.8 mL/mm Hg) was significantly lower than the preoperative rectal compliance in patients and that of healthy volunteers' rectum but was similar to that of the neorectum both 4 and 12 months postoperatively (Table IV). The neorectal compliance 4 months postoperatively was significantly lower than that of 12 months postoperatively, indicating that there was some adaptation 12 months postoperatively. As described by Akervall et al,28 reactive rectal contractions were observed at the onset of every distention of the barostat bag. In the neorectum, however, these contractions were followed by 1 or more extra contractions (median, 2; range, 1 to 6) at both 4 and 12 months postoperatively with an increased amplitude (Fig 3).
Four months postoperatively, the mean amplitude of these contractions was significantly larger than in the healthy volunteers' rectum, but the amplitude at 12 months was within the preoperative range ( Table IV). Pressure thresholds to induce neorectal and sigmoid colon sensation The pressure threshold to induce first sensation in the rectum of healthy volunteers was equal to that of the rectum in preoperative patients (Table IV). Similar agreement was shown for the thresholds for sensations of desire to defecate and of intolerable discomfort. The pressure threshold for first sensation in the healthy volunteers' sigmoid was also not different from the values in the healthy volunteers' rectum and those of the preoperative patients' rectum. However, the threshold for desire to defecate was significantly higher than that of the healthy volunteers' rectum and that of the preoperative patients' rectum. Moreover, in the sigmoid of healthy volunteers, sensation of intolerable discomfort could not be elicited, not even at 50 mm Hg (Fig 4).
In contrast, when the sigmoid was used for neorectal construction and placed on the pelvic floor, the pressure thresholds to induce the sensations of desire to defecate and of intolerable discomfort, both at 4 and 12 months postoperatively, dropped significantly and were similar to those of the normal rectum (Table IV). Volume thresholds to induce neorectal and sigmoid colon sensation The volume at first sensation was similar in the rectum, sigmoid, and neorectum of patients or healthy volunteers (Table IV). However, the volume at desire to defecate in the sigmoid of healthy volunteers and in the neorectum at 4 months was significantly lower than that of the rectum of both healthy volunteers and patients preoperatively. The volume at desire to defecate in the neorectum at 12 months showed a significant increase in comparison to 4 months postoperatively, not different any more from preoperative values and healthy volunteers' rectum. The volume at intolerable discomfort in the neorectum at 4 months was, like that at desire to defecate, lower than that of the rectum of healthy volunteers and patients preoperatively. At 12 months there was an increase in volume as compared to 4 months postoperatively, although not significant. The volume to induce intolerable discomfort at 12 months was still significantly lower than the volume at intolerable discomfort in the rectum of healthy volunteers. Data on the volume threshold for intolerable discomfort in the healthy volunteers' sigmoid are not available, because the intolerable discomfort sensation could not be elicited in the sigmoid of healthy volunteers. Discussion A growing number of publications report rising 5-year disease-free survival rates and declining local recurrence rates after total mesorectal excision for rectal carcinoma.1, 2 However, up to 60% of patients experience a decreased functional outcome 1 year postoperatively, ranging from soiling to episodes with fecal incontinence.3, 29, 30 Therefore, comprehension of the underlying pathophysiologic mechanism becomes increasingly important. In this study anal and rectal function in combination with clinical outcome was assessed in patients before and after surgery (by a consultant surgeon) for rectal cancer and compared to that of age-matched healthy volunteers. It was presumed that the clinical outcome, like in patients with an ileal pouch, would improve with an increase of neorectal compliance.31 However, similar to previous reports,3, 29 we showed that anorectal function was seriously diminished after TME surgery for rectal carcinoma with increased urgency and tenesmus and increased incidence of soiling and episodes with passive incontinence. Tenesmus and urgency were present 4 months postoperatively in 55% and 46% of the patients, respectively, both decreasing after 1 year to 36% and 18%, respectively. From a pathophysiologic point of view, urgency and tenesmus most likely result from altered motility and reservoir function of the neorectum. It is indeed becoming increasingly clear that these components play a pivotal role in normal physiology and continence.17, 29 As shown in healthy volunteers, the compliance of the sigmoid or descending colon, which is used to construct the neorectum, is significantly smaller than that of the normal rectum, explaining a similar reduction of the compliance of the neorectum in patients. Although there was some degree of adaptation in time, compliance remained significantly reduced after 1 year as compared to that of a normal rectum, resulting in smaller volumes necessary to induce sensation of defecation and discomfort. Furthermore, as shown by the neorectal contractions observed during distention, the neorectum is much more irritable than a normal rectum. These contractions will certainly contribute to the feeling of urgency and tenesmus, especially in the presence of decreased compliance. Interestingly, the volume at the threshold of desire to defecate and discomfort increased, whereas the distention-induced contractions decreased after 12 months, most likely explaining the decrease in urgency and tenesmus percentages. Similar pathophysiologic mechanisms are very likely involved in the urgency and tenesmus observed in patients with inflammatory bowel disease.32 In contrast to urgency and tenesmus, the occurrence of soiling and episodes with passive incontinence increased in time. Although the underlying pathophysiologic mechanisms of soiling and fecal incontinence are complex, it is clear that dysfunction of the internal anal sphincter is of crucial importance.4, 5, 7, 9, 12 Compared to age-matched healthy volunteers, preoperative basal pressure was significantly lower in patients, with 45% of patients having a basal pressure below the normal value and therefore a higher risk for a less favorable functional outcome. Moreover, postoperatively the anal resting pressure decreased even further, although not significantly, as reported by many other authors.5, 9, 33 This decrease in anal resting pressure, however, cannot fully explain the impaired anorectal function. Most interestingly, the percentage of patients with a positive rectoanal inhibitory reflex was decreased after 4 months, recovering in almost all patients after 1 year, similar to results reported by other groups.34, 35 One might argue that this finding may explain in part why episodes with passive incontinence increase. As previously discussed, the neorectum is more irritable and thus generates contractions even when small amounts enter. When the RAIR is absent, this will not result in opening of the sphincter. However, when RAIR has recovered after 12 months, increased pressure in the neorectum or small amounts of stool will induce a RAIR with further reduction of the basal pressure resulting in passive fecal incontinence. This mechanism is somewhat similar to the transient sphincter relaxations described in patients with diabetes, in which these spontaneous reductions in basal sphincter pressure are believed to contribute to the fecal incontinence and soiling in these patients.36 Another interesting finding in this study was the change in visceral sensation to distention of the sigmoid when it was moved to the pelvic floor. Indeed, in healthy volunteers, the thresholds to induce sensations in the sigmoid were much higher compared to that of the rectum, including that of the patients before surgery. Even distention of the sigmoid to 50 mm Hg was unable to induce a sensation of discomfort. However, when the sigmoid was transferred to the pelvic floor to function as a neorectum, sensation to pressure-controlled distention resembled that of a normal rectum, irrespective of the decreased compliance. These findings strongly suggest that receptors mediating these sensations are located in the pelvic floor and not in the rectal wall, which was recently propagated in a study in which a relationship was shown between rectal muscle tension and rectal sensation.37 On the basis of our findings and the possible underlying pathophysiologic mechanisms, one might hypothesize that the construction of a neorectum with a coloanal anastomosis is not a good choice from a functional point of view. First of all, the reservoir function should be increased, for example by creating a colonic pouch. Clinical outcome of patients treated as such are reported to be better as compared to patients who received a coloanal anastomosis, such as the patients in this study.38 Second, transection of the rectal wall as is done during a pouch procedure should theoretically reduce the irritability and contractility of the neorectum. However, because we have shown that the distention-induced contractility diminishes in time, this issue may become of minor importance after some time as is described in studies in which patients with either procedure have been observed for 2 years.8, 9 Further follow-up studies therefore are needed to confirm this. A major drawback of this study is that the number of patients is relatively small and the number of dropouts from follow-up in this group is relatively large. This type II error can probably underestimate or overestimate the data. The more subjective data such as clinical findings gathered with a questionnaire are especially prone to this phenomenon. However, it should be kept in mind that it is quite difficult to convince patients with cancer to participate in such a complicated and laborious study. In conclusion, anorectal function after TME surgery for rectal carcinoma is seriously hampered, resulting in increased urgency, tenesmus, and episodes with passive incontinence and soiling. Urgency and tenesmus most likely result from decreased compliance and increased contractility, both showing some degree of adaptation in time. This adaptation most likely explains the decrease in urgency and tenesmus after 1 year. In contrast, we showed that episodes with passive incontinence and soiling increase in time. Although we have no good explanation, the recovery of the RAIR in the presence of a lowered basal anal pressure most likely contributes to these problems. Further studies are needed to investigate whether a larger, more compliant reservoir will indeed increase functional outcome and eventually quality of life. References 1.
1
Zaheer S, Pemberton JH, Farouk R, Dozois RR, Wolff BG, Ilstrup D.
Surgical treatment of adenocarcinoma of the rectum.
Ann Surg. 1998;227:800–811. MEDLINE |
CrossRef
2.
2
Heald RJ, Moran BJ, Ryall RD, Sexton R, MacFarlane JK.
Rectal cancer: the Basingstoke experience of total mesorectal excision, 1978-1997.
Arch Surg. 1998;133:894–899. MEDLINE |
CrossRef
3.
3
Guillem JG.
Ultra-low anterior resection and coloanal pouch reconstruction for carcinoma of the distal rectum.
World J Surg. 1997;21:721–727. MEDLINE |
CrossRef
4.
4
Vassilakis JS, Pechlivanides G, Zoras OJ, Vrachasotakis N, Chrysos E, Tzovaras G, et al.
Anorectal function after low anterior resection of the rectum.
Int J Colorectal Dis. 1995;10:101–106. MEDLINE |
CrossRef
5.
5
Williamson ME, Lewis WG, Finan PJ, Miller AS, Holdsworth PJ, Johnston D.
Recovery of physiologic and clinical function after low anterior resection of the rectum for carcinoma: myth or reality?.
Dis Colon Rectum. 1995;38:411–418. MEDLINE |
CrossRef
6.
6
Miller AS, Lewis WG, Williamson ME, Holdsworth PJ, Johnston D, Finan PJ.
Factors that influence functional outcome after coloanal anastomosis for carcinoma of the rectum.
Br J Surg. 1995;82:1327–1330. MEDLINE |
CrossRef
7.
7
Hallbook O, Nystrom PO, Sjodahl R.
Physiologic characteristics of straight and colonic J-pouch anastomoses after rectal excision for cancer.
Dis Colon Rectum. 1997;40:332–338. MEDLINE |
CrossRef
8.
8
Lazorthes F, Chiotasso P, Gamagami RA, Istvan G, Chevreau P.
Late clinical outcome in a randomized prospective comparison of colonic J pouch and straight coloanal anastomosis.
Br J Surg. 1997;84:1449–1451. MEDLINE |
CrossRef
9.
9
Joo JS, Latulippe JF, Alabaz O, Weiss EG, Nogueras JJ, Wexner SD.
Long-term functional evaluation of straight coloanal anastomosis and colonic J-pouch: is the functional superiority of colonic J-pouch sustained?.
Dis Colon Rectum. 1998;41:740–746. MEDLINE |
CrossRef
10.
10
Horgan PG, O'Connell PR, Shinkwin CA, Kirwan WO.
Effect of anterior resection on anal sphincter function.
Br J Surg. 1989;76:783–786. MEDLINE |
CrossRef
11.
11
Molloy RG, Moran KT, Coulter J, Waldron R, Kirwan WO.
Mechanism of sphincter impairment following low anterior resection.
Dis Colon Rectum. 1992;35:462–464. MEDLINE |
CrossRef
12.
12
Tsunoda A, Shibusawa M, Kusano M.
Anorectal function after anterior resection with side-to-side anastomosis for carcioma of the rectum.
Dis Colon Rectum. 1999;42:77–81. MEDLINE |
CrossRef
13.
13
Ho YH, Tsang C, Tang CL, Nyam D, Eu KW, Seow-Choen F.
Anal sphincter injuries from stapling instruments introduced transanally: randomized, controlled study with endoanal ultrasound and anorectal manometry.
Dis Colon Rectum. 2000;43:169–173. MEDLINE |
CrossRef
14.
14
Jehle EC, Haehnel T, Starlinger MJ, Becker HD.
Level of the anastomosis does not influence functional outcome after anterior rectal resection for rectal cancer.
Am J Surg. 1995;169:147–153. Abstract |
Full-Text PDF (953 KB)
|
CrossRef
15.
15
Matzel KE, Stadelmaier U, Muehldorfer S, Hohenberger W.
Continence after colorectal reconstruction following resection: impact of level of anastomosis.
Int J Colorectal Dis. 1997;12:82–87. MEDLINE |
CrossRef
16.
16
Varma JS, Smith AN, Busuttil A.
Correlation of clinical and manometric abnormalities of rectal function following chronic radiation injury.
Br J Surg. 1985;72:875–878. MEDLINE |
CrossRef
17.
17
Sun WM, Donnelly TC, Read NW.
Utility of a combined test of anorectal manometry, electromyography, and sensation in determining the mechanism of ‘idiopathic’ faecal incontinence.
Gut. 1992;33:807–813. MEDLINE |
CrossRef
18.
18
Broens PM, Penninckx FM, Lestar B, Kerremans RP.
The trigger for rectal filling sensation.
Int J Colorectal Dis. 1994;9:1–4. MEDLINE |
CrossRef
19.
19
Pescatori M, Anastasio G, Bottini C, Mentasti A.
New grading and scoring for anal incontinence: evaluation of 335 patients.
Dis Colon Rectum. 1992;35:482–487. MEDLINE |
CrossRef
20.
20
Mertz H, Naliboff B, Munakata J, Niazi N, Mayer EA.
Altered rectal perception is a biological marker of patients with irritable bowel syndrome.
Gastroenterology. 1995;109:40–52. Abstract |
Full-Text PDF (1360 KB)
|
CrossRef
21.
21
Roe AM, Bartolo DC, Mortensen NJ.
New method for assessment of anal sensation in various anorectal disorders.
Br J Surg. 1986;73:310–312. MEDLINE |
CrossRef
22.
22
Kamm MA, Lennard-Jones JE.
Rectal mucosal electrosensory testing: evidence for a rectal sensory neuropathy in idiopathic constipation.
Dis Colon Rectum. 1990;33:419–423. MEDLINE |
CrossRef
23.
23
Rogers J, Henry MM, Misiewicz JJ.
Combined sensory and motor deficit in primary neuropathic faecal incontinence.
Gut. 1988;29:5–9. MEDLINE |
CrossRef
24.
24
Lindstrom MJ, Bates DM.
Nonlinear mixed effects models for repeated measures data.
Biometrics. 1990;46:673–687.
CrossRef
25.
25
Venables WN, Ripley BD.
Modern applied regression analysis with S-plus.
2nd ed. New York: Springer Verlag; 1997;. 26.
26
Heald RJ, Ryall RD.
Recurrence and survival after total mesorectal excision for rectal cancer.
Lancet. 1986;1:1479–1482. MEDLINE 27.
27
Enker WE.
Potency, cure, and local control in the operative treatment of rectal cancer.
Arch Surg. 1992;127:1396–1402. MEDLINE 28.
28
Akervall S, Fasth S, Nordgren S, Oresland T, Hulten L.
Rectal reservoir and sensory function studied by graded isobaric distension in normal man.
Gut. 1989;30:496–502. MEDLINE |
CrossRef
29.
29
Williams NS, Seow-Choen F.
Physiological and functional outcome following ultra-low anterior resection with colon pouch-anal anastomosis.
Br J Surg. 1998;85:1029–1035. MEDLINE |
CrossRef
30.
30
Nesbakken A, Nygaard K, Lunde OC.
Outcome and late functional results after anastomotic leakage following mesorectal excision for rectal cancer.
Br J Surg. 2001;88:400–404. MEDLINE |
CrossRef
31.
31
Bernstein CN, Rollandelli R, Niazi N, Robert M, Hirsh T, Munakata J, et al.
Characterization of afferent mechanisms in ileoanal pouches.
Am J Gastroenterol. 1997;92:103–108. MEDLINE 32.
32
Camilleri M, Ford MJ.
Review article: colonic sensorimotor physiology in health, and its alteration in constipation and diarrhoeal disorders.
Aliment Pharmacol Ther. 1998;12:287–302. MEDLINE |
CrossRef
33.
33
Kohler A, Athanasiadis S, Ommer A, Psarakis E.
Long-term results of low anterior resection with intersphincteric anastomosis in carcinoma of the lower one-third of the rectum: analysis of 31 patients.
Dis Colon Rectum. 2000;43:843–850. MEDLINE |
CrossRef
34.
34
O'Riordain MG, Molloy RG, Gillen P, Horgan AF, Kirwan WO.
Rectoanal inhibitory reflex following low stapled anterior resection of the rectum.
Dis Colon Rectum. 1992;35:874–878. MEDLINE |
CrossRef
35.
35
Holdsworth PJ, Johnston D.
Anal sensation after restorative proctocolectomy for ulcerative colitis.
Br J Surg. 1988;75:993–996. MEDLINE |
CrossRef
36.
36
Sun WM, Katsinelos P, Horowitz M, Read NW.
Disturbances in anorectal function in patients with diabetes mellitus and faecal incontinence.
Eur J Gastroenterol Hepatol. 1996;8:1007–1012.
CrossRef
37.
37
Rao GN, Drew PJ, Monson JR, Duthie GS.
Physiology of rectal sensations: a mathematic approach.
Dis Colon Rectum. 1997;40:298–306. MEDLINE |
CrossRef
38.
38
Wexner SD, Alabaz O.
Anastomotic integrity and function: role of the colonic J-pouch.
Semin Surg Oncol. 1998;15:91–100. MEDLINE |
CrossRef
Amsterdam, The Netherlands From the Department of Surgery, Department of Clinical Epidemiology & Biostatistics, and the Department of Gastroenterology, Academic Medical Center, Amsterdam, The Netherlands ☆ Reprint requests: Guy E. E. Boeckxstaens, MD, Academic Medical Center, Dept of Gastroenterology, C2, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. ☆☆ 0039-6060/2003/$30.00 + 0 PII: S0039-6060(02)21609-8 doi:10.1067/msy.2003.3 © 2003 Published by Elsevier Inc. | |
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