Anal Sphincter Function and Rectal Reservoir after Sphincter Saving Operations for

Carcinoma of the Rectum

Naomi IWAI, Kyozo HASHIMOTO, Hirofumi KANEDA, Osamu KOJIMA Bunzo NISHIOKA and Susumu MAJIMA,

ABSTRACT: Anal sphincter function and rectal reservoir were studied in 27 patients after low anterior resection, in 6 after Welch or Turnbul l type pull-through surgery and in 3 after Bacon type pull-through surgery. Six- teen patients who had undergone right hemieolectomy served as a control group. Anal sphincter function immediately after low anterior resection was diminished, but improved during the following 6 months. Rectal capacity was much reduced immediately after surgery, but increased with time, and the neorectum could to some extent adapt to its new role as a reservoir. After pull-through operations, anal canal pressure and rectal compliance were significantly lower than after low anterior resection or right hemicolectomy. These findings may explain the increased frequency of bowel action after pull-through operations.

KEY W O R D S : anorectal manometry, rectal cancer, sphincter-saving operations

INTRODUCTION

The development of various types of sphincter-saving resections for carcinoma of the rectum had led to renewed interest in the function of the pelvic floor muscles as well as that of the anal sphincters. We described in an earlier report I the sphincter function of the preserved anorectum in patients treated with low anterior resection or Bacon type operations of the rectum. Rectal reservoir function after these sphincter-saving opera- tions was also tested to complete the evalua- tion of postoperative continence, because both normal rectal sensation and reflex

First Department of Surgery, Kyoto Prefectural Uni- versity of Medicine, Kyoto, Japan

Reprint requests to : Naomi Iwai, First Department of Surgery, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto 602, Japan

relaxation of the anal sphincters in response to rectal distension are considered to be essential for normal continence. We now report sphincter and rectal reservoir func- tions following low anterior resection for pull-through operations of the rectum.

PATIENTS AND METHODS

Thirty-six patients who underwent sphinc- ter-saving resection for carcinoma of the rectum were included in this study. There were 24 men and 12 women with a mean age of 60.8 years (range 32-82 years). As shown in Table 1, low anterior resection was performed in 27 patients, Welch type or Turnbull type pull-through in 6, and Bacon type pull-through in 3. The anorectal stump was examined by palpation or a small sigmoidoscope. The anorectal stumps were 6.34-0.2 cm (mean4-SEM) long in low an-

JAPANESE JOURNAL OF SURGERY, VOL. 13, No. 5 pp. 420--425, 1983

Volume 13 Number 5 Anal sphincter function

Table 1. Procedures of Sphincter-saving Operation in 36 Patients with Car- cinoma of the Rectum (Mean_J: SEM)

421

No. of Rectal Stump Procedures Patients (cm from anal verge)

Low Anterior Resection 27 6.3=t=0.2 Welch or Turnbull Type Pull-through 6 4.0• Bacon Type Pull-through 3 3.5

] 111111 I I [ ]~l I I I I I I I I I I I I I I I I I I Y ~ l ; ~ [ l l I l l l IF ' I l l l l l l l r ] l II I l l l l l l / i [ ] ~ I T [ I I i l I I I I IT]~II I I I I I I I I I r I I

8 7 6 5 4 3 2.5 2 1.5 1 0 cm

cmH20 10sec

Fig. 1. Anoreetal pressure profile of a normal subject. Distances are centimeters from the anal margin. A marked high pressure zone (H.P.Z.) in the anal canal was observed, and the length of this high pressure zone was defined as the anal canal length.

terior resection, 4.0:t:0.3 cm in Welch or Turnbu l l type, and 3.5 cm in Bacon type resection. Anorectal manomet r ic studies were performed 3, 6 months, and more than 1 year following the operation. Manomet r ic studies were also performed in 16 patients treated with r ight hemicolectomy (control group), 11 men and 5 women, with a mean age o f 64.2 years (range 44-78 years).

T h e anorectal manometr ic study was per- formed using an infusion method. T he probe was perfused with water at a constant rate of I0 ml /hour with an automat ic infusion pump. This appara tus was connected to a t ransducer (Toyo Baldwin Co., Ltd. , To- kyo, Japan) , and the pressure was recorded on a polygraph (Sanei L-012, Sanei Co., Ltd. , Tokyo, Japan) . Zero pressure, used th roughout this study, was determined by recording atmospheric pressure at the anal margin. All investigations were under taken with the patients placed in the lateral posi- tion. The anorectal pressure profile was first recorded in centimeters by wi thdrawing the probe which was introduced to 8 cm above the anal margin (Fig. 1). After meas-

urement of the anorectal pressure profile the presence or absence of an anorectal reflex was determined by distending the balloon in the rec tum for 10 sec with 20 to 30 ml of air (Fig. 2). The voluntary squeezing pressure was recorded 2 cm above the anal margin. Rectal sensation and rectal compl iance were measured in the following way: as the balloon placed in the rec tum was inflated, the subject was asked to say when he first noticed a sensation of rectal distension. The volume in the balloon at tha t point was recorded as " the threshold for sensation." The largest volume of distension which the subject could tolerate was also recorded and designated the " m a x i m u m tolerable volume" (Fig. 3). Finally a pressure-volume curve of the rec tum was made, and rectal com- pliance (zlv/Ap) was calculated by dividing changes of pressure at the l inear port ion of the curve.

Results were express as meansz[:SEMs, and Student 's t-test was used for statistical analysis. A P-value of less than 0.05 was considered to be significant.

422 Iwai et al. Jpn. J . Surg. September 1983

Rectal Distension

Pressure in Anal Canal

cmH20 10sec a

I : T ; F: ? : : : ; i : ! ' E : E . . . . . . ' . . . . . . . . . . : . ' , " . I I I I H I ! N E : : : : I T E q T I T ~ I I T I I T T r l ,~ F1 I , - - ~ - - . I T ' ~ ' ' I T I I T I T I T E '

Rectal Distension

Pressure in Anal Canal 50

cmH20 10sec b

Fig. 2. a Presence of an anorectal reflex. A typical fall in anal canal pressure cor- responding to rectal distension is observed, b Absence of an anorectal reflex. There was no fall in anal canal pressure in response to rectal distension.

Threshold for Sensation Maximum Tolerable Volume l *

Volume of Air 60 (ml) 90 120 150 180 210

5() ~ ~ . ~ . _ ~ ~

0 l ~ _ ~ ~ - - ~

cmH20

Fig. 3. Pressure-volume curve of the rectum in a normal subject. Volumes are the volume of air in the balloon placed in the rectum. Threshold for sensation and maximum tolerable volume were recorded as the balloon was inflated.

R E S U L T S

Patients with low anterior resection O f the 27 patients treated with low ante-

rior resection, there was no anastomotic leak in 21 and adequate anal control was achieved within 3 months following opera- tion. The remaining 6 patients with anas- tomotic leaks had frequent soiling with 20 to 30 bowel movements a day dur ing the first 3 months after operation. As the local in- f lammat ion associated with anastomotic leak disappeared, the fecal incontinence improved up to one year following operation.

A summary of the manomet r ic studies in these patients is presented in Tab le 2.

Three months after surgery, part icularly in patients with anastomotic leaks, anal pres- sure was significantly lower (p<0 .01) than in the normal controls, and the length of the high pressure zone was significantly shorter (p<0 .01) . Wi th regard to the anorectal reflex, 14 of the 21 patients examined 3 months following operat ion showed a typical anorectal reflex, but the remaining 7 pa- tients, including 6 with anastomotic leaks, had no anorectal reflex. However, in 5 of these 7 patients, anorectal reflex developed by the time of the third examinat ion (more than one year after the operation). The values of rectal pressures and voluntary squeezing were not significantly different between the patients with low anterior

Volume 13 Number 5

T a b l e 2.

Anal sphincter function

Sphincter Function following Low Anterior Resection (Mean ~ SEM)

423

Time of Rectal Anal H.P.Z. Anorectal Voluntary Post Op. Pressure Pressure Squeezing

Investigation (cm tt20) (cm H20) (cm) Reflex (cm HzO)

3 Mo 9.7~:1.5 58.4~6.5" 2.1• 14/21 (67%) 88.6• Low (n=21) Anterior 6 Mo 5.5~:1.5 74.0• 2.3• 5/5 (100%) 84.0:t-10.3 Resection (n=5)

>1 Yr 8.5~:I.7 73.4i8.9 2.5:~0.2 5/7 (71%) N. (n=7)

Normal (n= 16) 6.5:~1.1 80.9~4.6" 3.04-0.2* 16/16 (100%) 66.3~10.4 Controls

H.P.Z., High Pressure Zone; N., not examined *p<0.01

T a b l e 3. Rectal Reservoir Function following Low Anterior Resection (Mean=~ SEM)

Maximum Rectal Time of Threshold for Tolerable Post Op. Sensation Volume Compliance

Investigation (ml) (ml) (ml/cm HaO)

3 Mo 37.1 ~:3.3" 60.014.6" 2 .3!0.5"* (n=21)

Low Anterior 6 Mo 55.0~:4.1" 95.0• 2.8• Resection (n = 5)

> 1 Yr 86.0• 15.6"* 135.0=t= 17.0t 5.4• 1.2",** (n=7)

Normal (n= 16) 132.7s 199.5• 15.8t 11.54-0.9" Controls

*p<0.01 **p<0.05 tp<0.02

resection and the normal controls. With regard to rectal reservoir function,

as shown in Table 3, the mean threshold for sensation, the mean max imum tolerable volume and the rectal compliance increased with time and were 86.0:L15.6, 135.0• and 5.4:t= 1.2, respectively, one year or more after operation. All these values were sig- nificantly lower than those of normal controls.

Patients with abdomino-anal pull-through operations

In the patients treated with abdomino- anal pull-through operations, clinical assess- ment showed poor anorectal function during the first 6 months after operation, but accept- able anorectal function was regained within one year, and their social activities were not

restricted, despite occasional soiling. The results of manometric studies in these

9 patients are presented in Tables 4 and 5. There were no statistically significant dif- ferences in the rectal resting pressure at the different intervals after operation between normal controls and the patients who had undergone abdomino-anal pull-through operation. However, both the anal pres- sures and the high pressure zone were sig- nificantly lower or shorter than in the normal controls.

Anorectal reflex was present in 4 of the 6 patients with Welch or Turnbul l type opera- tion, 6 to 12 months after operation, and the voluntary squeezing of these patients was not significantly different from that of normal

424 lwai et al. Jpn. J . Surg. September 1983

Table 4. Sphincter Function following Abdomino-anal Pull-through Operations

Time of Rectal Anal H.P.Z. Anorectal Voluntary Squeezing Post Op. Pressure Pressure (cm) Reflex (cm H20

Investigation (em H~O) (cm H20)

Welch or < 1 Yr 8.8:k0.4 50.9:k8.9" 1.6:j:0.2"* 4/6 62.74-15.3 Turnbull (n = 6)

Bacon >1 Yr 8.7• 55.3• 1.84-0.1"* 1/3 24.0 (n=3)

Normal (n= 16) 6.5:k 1.1 80.94-4.6* 3.04-0.2** 16/16 66.34-10.4 Controls

* p<0.02 ** p<0.001 H.P.Z.==High pressure zone

Table 5. Rectal Reservoir Function following Abdomino-anal Pull-through Operations

Threshold Maximum Rectal Time of for Tolerable Post Op. Sensation Volume Compliance

Investigation (ml) (ml) (ml/cm H20)

Welch or Turnbull

Bacon

Normal Controls

<1 yr 50.7:k 7.4" 77.84-8.0* 1.14-0.2" (n -6 )

>1 Yr 60.0 75.0~24.7" 1.14-0.3" (n=~)

(n= 16) 132.7i8.0" 189.5zk 15.8" 11.54-0.9"

* p < 0 . 0 0 1

controls. Among the 3 patients with Bacon type operation, however, the anorectal reflex was present in only one more than one year following operation, and voluntary squeezing was much weaker than in patients with Welch or Turnbull type pull-through opera- tions or in normal controls.

With regard to the rectal reservoir func- tion (Table 5), values of threshold for sensa- tion and max imum tolerable volume in the 6 patients with Welch or Turnbul l type operation and the 3 with Bacon type opera- tion were significantly lower (p <0.001) than in the normal controls, and the rectal com- pliance in these patients was also significant- ly lower (p<0.001).

DIscussioN

The efficacy of sphincter-saving resections for carcinoma of the rectum has not been clearly established, in terms of anal function. The patients described herein had been treated for carcinoma of the rectum by low anterior resection, Welch or Turnbull type operation, or Bacon's pull-through opera- tion. Manometr ic assessment of postoperative anorectal function was performed in these patients at various intervals after surgery.

In the patients with low anterior resection, the anal canal pressure and the length of the high pressure zone 3 months after operation were significantly lower than in normal con- trols. However, these values improved and

Volume 13 Number 5 Anal sphincter function 425

were not s ignif icant ly different f rom those of n o r m a l controls by 6 months after the opera- t ion. The anorec ta l reflex was es tabl ished in 25 of the 27 pat ients wi th in 6 months after the opera t ion , bu t in 2 wi th severe anas- tomot ic leaks, the anorec ta l reflex was absent even one yea r postopera t ively . These results ind ica te tha t ana l sphinc ter funct ion imme- d ia t e ly after low an te r io r resection was d imin i shed in a lmost all o f the pat ients , pa r - t i cu la r ly in those wi th anas tomot ic leaks. However , this funct ion i m p r o v e d wi th in 6 months fol lowing the opera t ion in a lmost all o f the pat ients wi th low an te r io r resection. Suzuki et al. 2 r epo r t ed no rma l ana l cana l pressures a n d length of the ana l cana l in pa t ien ts who had undergone low an te r io r resection. I n only one of thei r 16 pa t ien ts d id anas tomot ic leak occur.

I n the present series, rec ta l reservoir func- t ion was also assessed by rec ta l sensat ion and rec ta l compl iance . T h e threshold for sensa- t ion, m a x i m u m to lerable vo lume and rec ta l compl iance improved wi th t ime after low an te r io r resection, b u t d id not r each n o r m a l values. These results suggest t ha t a l though rec ta l capaci t ies were r educed after low an te r io r resection, the capac i ty of the neo- r e c t u m increases wi th t ime and can to some extent a d a p t to its new role as a reservoir .

I n Welch or T u r n b u l l type a n d Bacon type pu l l - th rough operat ions , on the o ther hand , ana l cana l pressures were s ignif icant ly lower than n o r m a l even one yea r or more af ter surgery. Bennet t et al. 3 a n d Cortesini 4 r epo r t ed s imilar results of ana l cana l pressure reduc t ion af ter T u r n b u l l or Bacon type pul l - t h rough operat ions . These results ind ica te t ha t the in te rna l sphinc te r which cont r ibu tes m a i n l y to the ma in t enance of ana l cana l pressure at rest is i m p a i r e d to some extent in the pu l l - th rough procedures , pa r t i cu l a r l y in the Bacon type opera t ion . Also the ano- rec ta l reflex was present in only one of the 3 pat ients t r ea ted wi th Bacon type pul l - t h rough opera t ion more t han one yea r after

the opera t ion , because r emova l of pa r t of the in te rna l sphinc ter muscle as well as of the levator ani was inevi table . O n the cont rary , af ter Welch or T u r n b u l l type pu l l - t h rough operat ions , 4 of the 6 pa t ien ts h a d an ano- rec ta l reflex even wi th in one y e a r and the leva tor ani and in te rna l sph inc te r were well preserved. I t has been cons idered tha t the receptors responsible for the anorec ta l reflex are loca ted in the rectal wall . s O u r results, however , suppor t the view tha t the receptors subserving the anorec ta l reflex lie not only in the rectal wal l bu t also in the pelvic floor, possibly in the levator an i muscle.

Pat ients t r ea ted with pu l l - t h rough opera- tions had a signif icant r educ t ion in the threshold for sensation, m a x i m u m tolerable vo lume and rec ta l compl iance , c o m p a r e d wi th pa t ien ts who had unde rgone low ante- r ior resection, or in the n o r m a l controls. This f inding p r o b a b l y accounts for the in- creased f requency of bowel ac t ion after the pu l l - t h rough operat ions , in add i t i on to a sig- n i f icant reduc t ion of ana l cana l pressure.

(Received for pub l i ca t ion on Dec. 10, 1982)

References

1. Iwai, N., Hashimoto, K., Yamane, T., Kojima, O., Nishioka, B., Fujita, Y. and Majima, S. : Physiologic status of the anorectum following sphincter-saving resections for carcinoma of the rectum. Dis. Colon Rectum. 25: 652-659, 1982.

2. Suzuki, H., Matsumoto, K., Amano, S., Fujioka, M. and Honizumi M. : Anorectal pressure and rectal compliance after low anterior resection. Br. J. Surg. 67: 655-657, 1980.

3. Bennett, ][(. C., Buls, J., Kennedy, J. T. and Hughes E. S. R.: The physiologic status of the anorectum after pull-through operations. Surg. Gynecol. Obstet. 136: 907-913, 1973.

4. Cortesini, C. : Anorectal reflex following sphincter- saving operations. Dis. Colon Rectum: 320- 326, 1980.

5. Lawson, J. O. N. and Nixon, H. H.: Anal canal pressures in the diagnosis of Hirschsprung's disease. J. Pediatr. Surg. 2: 544-552, 1967.