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Delayed Rectal Sensation With Fecal Incontinence
GASTROENTEROLOGY 1986;91 :1186-91
Delayed Rectal Sensation With Fecal Incontinence Successful Treatment Using Anorectal Manometry WILLIAM D. BUSER and PHILIP B. MINER, Jr. Department of Medicine, Division of Gastroenterology, University of Kansas Medical Center, Kansas City, Kansas
Retraining of the external sphincter response to rectal distention and improving the sensory threshold to balloon distention is documented as effective treatment for fecal incontinence in selected patients. Using anorectal manometric techniques, delayed conscious rectal sensation was demonstrated in 28% of 46 consecutive patients referred for fecal incontinence. In patients with delayed recognition of balloon distention, conscious rectal sensation seemed to correlate with a consistent level of internal sphincter relaxation rather than the primary stimulus of balloon distention of the rectum. Anorectal retraining techniques resulted in [a) correction of sensory delay of 2-22 s, [b) elimination of fecal incontinence, and [c) improved sensory threshold in 10 of 13 patients. This previously unreported sensory abnormality represents a treatable manometric abnormality identified by anorectal motility in patients with fecal incontinence. The recent investigations of the physiology of the anal sphincteric barrier have helped design retraining techniques for reestablishing bowel control in patients with fecal incontinence. Retraining techniques advocate the use of anorectal manometry to strengthen the muscular barrier and to improve sensory acuity to rectal distention. Success in treating incontinence has been achieved using rectal balloon distention to coordinate voluntary external sphincter contraction (1). Received January 22, 1985. Accepted April 23, 1986. Address requests for reprints to: Philip B. Miner, Jr., M.D., Medicine Office-4035D, University of Kansas Medical Center, 39th and Rainbow, Kansas City, Kansas 66103. The authors thank Lyn Loveland and Judy Bowsky for their nursing assistance, and Wanda Lantz for expert secretarial assistance. © 1986 by the American Gastroenterological Association 0016-5085/86/$3.50
This technique coordinates sensory impulses and voluntary muscular effort; thus, intact rectal sensation is imperative for successful retraining. The importance of sensation has been clearly documented in children with meningomyelocele (2). As reflex internal sphincter relaxation is directly proportional to the volume of balloon distention, it follows that enhancing the rectal sensory threshold to smaller balloon volumes should improve continence by modulating the strength of the anal sphincteric barrier. This has been accomplished in diabetic (3) and nondiabetic (4,5) patients with the predicted improved fecal continence. We have identified a previously unrecognized sensory deficit in 13 of 46 consecutive patients referred for fecal incontinence. These patients did not recognize that a balloon had been distended in their rectum for several seconds. This sensory delay in the time from rectal balloon distention to conscious recognition of a sensation of rectal fullness often occurred at the nadir of internal sphincter relaxation allowing the patient to recognize rectal fullness when the sphincteric barrier was the weakest. The clinical and manometric findings and the results of the retraining of the 13 patients with this previously unreported finding are presented.
Materials and Methods Between September 1983 and August 1984, 46 patients with fecal incontinence were referred for anorectal studies and entry into our retraining program. The presumed underlying causes of the fecal incontinence in these patients are listed in Table 1. Anorectal manometry was performed in all patients, whereas retraining was restricted to patients who were alert, cooperative, highly motivated, and readily able to respond to verbal commands. Although patients with severe neurologic deficits were accepted for training, most
November 1986
FECAL INCONTINENCE AND RECTAL SENSORY DELAY
Table 1. Underlying Causes in All 46 Patients Referred With Fecal Incontinence
any change in rectal sensation was emphasized. If the verbal response to balloon distention was delayed or if the volume was not sensed, the patient was rechallenged with the same volume and told when the rectal balloon was being distended. Several repetitions of this step were often required before improved awareness of rectal sensation occurred. Before decreasing the balloon volume, the patient had to respond accurately to an unsignaled stimulus. The patients usually corrected the sensory delay first and then improved the sensory threshold. The second phase of retraining was performed with the patient contracting the external sphincter in response to sensing rectal balloon distention. During the manometric session, the patient was encouraged to learn to contract the puborectalis and external anal sphincter to gain the highest pressures. Between manometry sessions the patients exercised the puborectalis and external anal sphincter muscles as directed by manometric results. Five patients were initially given low-dose loperamide (Imodium, Janssen Pharmaceutica Inc., Piscataway, N.J.) to increase internal sphincter tone (6). The patients required from one to three retraining sessions to obliterate the delay in sensation and lowering of sensory thresholds. The length of each session ranged from 15 to 30 min. Criteria for a good response to anorectal manometric retraining included (a) obliteration of the delay in sensation, (b) decrease in the sensory threshold, and (c) resolution of the fecal incontinence and the extreme urgency. The data were analyzed with the paired Student's t-test, with standard deviation used to express variation from the mean.
Medical
Surgical
Diabetes mellitus Vincristine Meningomyelocele Rectal pain Pelvic fracture Compression fracture of spine Proctitis Perineal descent Myasthenia Arthritic spine Radiation to pelvis Obstetric trauma
Hemorrhoidal repair Rectocele repair Anal repair Transurethral resection of the prostate Radical prostatectomy Laminectomy Spinal fusion L4 to S1
of the 13 patients with delayed sensation had no gross neurologic deficits (although specific neurologic testing, such as pinprick, proprioception, and tactile touch testing was not systematically done beyond the perineum). Anorectal manometry was performed using a low compliance water perfusion system (Arndorfer) with a triplelumen catheter having radially oriented ports spaced at 0.5-cm intervals. Sensory threshold, internal sphincter response, and external sphincter responses were evaluated using a 150-ml capacity balloon attached 5 cm from the distal catheter port. The balloon volume for testing sensation was infused in 2-3 s and stepped in 5-ml increments. The following measurements were made: (a) the mean maximal basal and the mean maximal squeeze pressures by station and pull-through techniques; (b) sensory threshold as defined by the smallest volume of rectal distention repeatedly (three or more times) and reproducibly (>80% accuracy) sensed by the patient; and (c) the delay in sensation, that is, the number of seconds from rectal balloon distention to conscious recognition of rectal pressure. The delay in sensation was measured by marking the tracings from complete balloon distention to the patients' verbal recognition. The patients were instructed to respond immediately to any change in rectal sensation. Initially, a large volume of air was given, usually 60 ml, to allow the patient to determine the nature of the stimulus. This volume was sensed by a majority of patients and verified their ability to respond quickly. If 60 ml was not perceived, then larger volumes were used. A small number of patients were unable to sense the maximum volume administered (150 ml) and no attempt at retraining could be started. If delayed sensation appeared to be present, the patient was rechallenged and told when the volume of air was injected to test for the ability to respond versus a delay in sensation. In all cases in which we report delayed sensation, the patient acknowledged that he did not immediately sense rectal distention. In patients found to have sensory delay, the sequence of retraining efforts was (a) obliterate the sensory delay, (b) improve anorectal sensory threshold, and (c) enhance external sphincter motor response. The patients were reinstructed in the importance of concentrating on changes of rectal sensation. Immediate verbal response to
1187
Results In the 46 consecutive patients with fecal incontinence referred for anorectal studies, welldocumented delayed rectal sensation was present in 13. These patients had no other gross neurologic abnormalities. The remaining 33 patients responded immediately to rectal distention, although several had abnormal sensory thresholds. An immediate response to rectal balloon sensation was also noted in separate groups of patients referred for constipation or perineal pain.
Clinical Data The clinical details of the 13 patients with delayed rectal sensation are presented in Table 2. The 7 women and 6 men in this group ranged in age from 13 to 66 yr. The duration of fecal incontinence varied from a few months to 23 yr (Table 2). The frequency of incontinent episodes varied from 1-2 times per month (3 patients), to daily or several times a week (7 patients), to multiple times a day (2 patients). Extreme urgency was a predominant symptom in 10 of the 13 patients. The 3 patients without a sense of urgency reported nighttime soil-
1188
GASTROENTEROLOGY Vol. 91 , NO.5
BUSER AND MINER
Table 2. Clinical Data on the 13 Patients With Delayed Conscious Rectal Sensation Severity of incontinence a
Duration of incontinence (rna)
Patient No.
Age (yr)
Sex
1 2 3
58 66 59
F M M
4
38
F
5 6
51 45
F F
1 2
8 276
7 8 9
70 13 45
M M F
1 4 2
2 156 120
10 11 12
63 63 66
M M F
3 3 3
2 120 9
13
60
F
4
5
Q
18 36 2
3 2 0 Bladder cyst 1
Underlying cause b Perineal descent, T AH, 4 LB TURF, low back pain Radical prostatectomy Laminectomy and discectomy, L4 to S1 fusion Perineal descent Rectocele and cystocele repair, hemorrhoidal surgery, 4 LB TURP and radiation to pelvis Encopresis Back injury-fall, TAH, anal tear with delivery None Vincristine Arthritic spine, bile salt catharsis Bile salt catharsis, 4 LB
4
Severity of symptoms are coded as follows : 0 = urgency only, 1 = 1-2 a month , 2 = several times a week, 3 = once a day, 4 = multiple times a day. b TAH, total abdominal hysterectomy; LB, live births ; TURP, transurethral resection of the prostate.
ing or recognized soiling only after incontinent stool had passed. One patient complained of extreme rectal urgency although he was never incontinent. A variety of underlying conditions could have been responsible for incontinence. Eight patients had more than one condition. In 1 patient no underlying condition was suggested by the history or physical examination. Eight patients had at least one relevant operation that could be implicated as a cause of the incontinence. These included a radical prostatectomy, laminectomy, and discectomy, L4 to Sl fusion, rectocele and cystocele repair, hemorrhoidal surgery, transurethral resection of the prostate (2 patients), and total abdominal hysterectomy (2 patients). Four patients had obstetrical-associated conditions, including 3 patients with multiple vaginal deliveries and 1 patient who sustained an anal tear with delivery. The 3 patients with low back pain had (1) arthritic spine, (b) injury occurring during a fall, and (c) idiopathic back pain. Other conditions noted included bile salt catharsis, previous vincristine therapy complicated by a sensory neuropathy, bladder cyst, and perineal descent (2 patients).
ter movement made accurate measurement of the percentage of internal anal sphincter relaxation at which recognition occurred technically difficult. Despite these difficulties, the percentage of internal anal sphincter relaxation at the time of recognition appeared relatively constant for each individual. 22 20 18
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In this subset of 13 patients, the maximum time from balloon distention to conscious recognition ("rectal sensory delay") ranged from 2 to 22 s, with a mean of 8.7 ± 5.3 s and a median of 7 s (Figure 1). Conscious rectal sensation appeared to occur at a fixed level of internal anal sphincter relaxation. The variations in the recorder baseline and slight cathe-
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Anorectal Manometry
16
8 5·6·11
6 4·8·13
4 2 0
Pre
Responders
Post
Figure 1. Time from rectal balloon distention to conscious rectal sensation before and after retraining in the 13 patients with sensory delay.
FECAL INCONTINENCE AND RECTAL SENSORY DELAY
November 1986
70
60
9 10
50
11
o Nonresponders
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1189
deviations from our normal mean. The mean maximal squeeze pressure before training was 80 ± 24 mmHg, with a median of 75 mmHg and a range of 48-130 mmHg. The mean maximal squeeze pressure increased after training to 94 ± 28 mmHg (paired Student's t-test; p < 0.005), with a median of 98 mmHg and a range of 48-130 mmHg. We consider a mean maximal squeeze pressure of 2:: 11 0 mmHg to be normal.
...
(J)
.s::. t>- 30
...0
Response to Retraining
(/)
c: (J)
(J)
20 1 2
10
0
Pre
Responders
Post
Figure 2. Anorectal sensory thresholds before and after sensory retraining in the 13 patients with sensory delay. There was significant improvement in the sensory threshold after retraining (p < 0.001).
Recognition of balloon distention occurred after an internal anal sphincter relaxation of 10%-70% of the maximal basal pressure. Patients with the highest percentage of relaxation before sensation were those with the largest volume sensory thresholds. In only 1 case did we fail to document internal anal sphincter relaxation as a possible sensory stimulus. The initial volume sensory thresholds are shown in Figure 2. The minimum perceived volume ranged from 15 to 65 ml, with a mean of 39 ± 16 ml and a median of 35 ml. Wald and Tunuguntla (3) reported a mean normal sensory threshold of 12.5 ml. In our patients, we consider a sensory threshold of 15 ml or less as normal, although the mean threshold value is -10 ml. Because we determine the volume sensory threshold in 5-ml increments, the exact mean value has little importance. Sphincter pressures measured by anorectal manometry in these 13 patients are summarized as follows (Figure 3). The mean maximal basal pressure before training was 50 ± 20 mmHg, with a median of 40 mmHg and a range of 27-92 mmHg. The mean maximal basal pressure increased after training to 62 ± 23 mmHg (paired Student's t-test; p < 0.01)' with a median of 58 mmHg and a range of 38-103 mmHg. Only 10 patients were studied more than 1 mo after successful retraining. In our patients, a mean maximal basal pressure of <40 mmHg fell two standard
Twelve of the 13 patients undergoing retraining had a good response as manifested by control of the fecal incontinence and rectal urgency. The delayed sensation was corrected iIi all patients, and several patients were able subsequently to distinguish the immediate rectal sensation of balloon distention from the previous recognized sensation that occurred several seconds after rectal balloon distention (Figure 1). There was significant improvement in the sensory threshold (paired Student's t-test; p < 0.001), with 10 of 13 patients improving (Figure 2). One patient (patient 3) continued to complain of intolerable urgency without incontinence, and he was unable to improve his sensory threshold with retraining efforts. The duration of follow-up has ranged from 16 to 30 mo. 140 120
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E
80
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60
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Pre Post Mean Maximum Basal Pressure
Pre Post Mean Maximum Squeeze Pressure
Figure 3. Anorectal mean maximal basal pressures and mean maximal squeeze pressures before and after retraining episodes. Three patients had improved symptomatically after a single session and were not restudied. The posttraining means of both the mean maximal basal pressure and mean maximal squeeze pressure were significantly different (p < 0.01 and p < 0.005, respectively).
1190
BUSER AND MINER
GASTROENTEROLOGY Vol. 91. No.5
Discussion Delayed awareness of rectal balloon distention has not been described in patients with fecal incontinence. The delayed sensory awareness in conjunction with the impaired sensory threshold described in these 13 patients with fecal incontinence appears to be a common and easily treated abnormality. Several accepted causes of incontinence were present in these patients (Table 2), although perineal or pelvic injury was most common (9 of 13 patients). Successful retraining was independent of the putative cause of the fecal incontinence. No consistent features of the medical history or physical examination predicted sensory delay, although extreme urgency to defecate or the unrecognized passage of stool were common symptoms. The delay in recognition of rectal fullness and internal sphincter relaxation may explain the profound sense of urgency to defecate. The manometric findings in 1 patient (patient 7) with delayed sensation are illustrated in Figure 4. In this selected part of the motility, the perfusion port senses both internal anal sphincter relaxation and external anal sphincter contraction. The relaxation response to 30-ml balloon distention was not sensed (Figure 4A). The second motility segment shows the anal canal pressure when the patient squeezed as soon as the volume was sensed. The rapid squeeze after the 6-s delay occurs after an internal anal sphincter relaxation of about 50%. The findings after retraining are illustrated in Figure 4B. In the first section, 40 ml of air was instilled to document internal anal sphincter relaxation. The second part illustrates the voluntary response to 20 ml. The squeeze is immediate, with the slope perpendicular to the resting pressure. The final sensory threshold was 15 ml in this patient. The following sequence of events appears to occur in these patients. In the presence of impaired volume sensation and delayed awareness, fecal material enters the rectum without conscious recognition. As the rectum distends, internal anal sphincter relaxation occurs with failure of timely contraction of the external anal sphincter, resulting in a relaxed anal channel. The late recognition of volume in the rectum or the passage of stool into the anal canal gives the patient a sense of extreme urgency. With the sphincteric barrier compromised by normal reflex relaxation from a distended rectum, the attempt to overcome progressive internal anal sphincter relaxation fails, resulting in fecal incontinence with a very brief warning. These observations explain the history of very brief warning or unrecognized passage of stool, especially when the stool is solid. The delay in conscious sensation is too long to be due primarily to balloon distention. External sphinc-
130ml
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0 TIME (seconds)
Figure 4. A. A manometric tracing from case 2 (patient 7) demonstrates the delay of conscious sensation to rectal balloon distention. The left tracing demonstrates internal sphincter relaxation to 30 ml of rectal balloon distention without conscious sensation. In the right tracing, rectal balloon distention induces internal sphincter relaxation followed 6 s later by conscious recognition and voluntary external sphincter contraction (squeeze). B. A follow-up manometric tracing 1 mo later demonstrates correction of the sensory delay. The left panel demonstrates internal sphincter relaxation to 40 ml of rectal balloon distention. The right tracing demonstrates voluntary external sphincter contraction without delay after 20 ml of rectal balloon inflation.
ter contraction could account for conscious sensation as external sphincter contraction occurs simultaneously with balloon distention and internal sphincter relaxation in normal patients. External anal sphincter contraction was absent at the time of sensation in the majority of our patients, making conscious awareness due to external sphincter contraction an unlikely possibility. Furthermore, external anal sphincter contraction may be partly dependent on cortical function (7), suggesting that external anal sphincter contraction is a result rather than a cause of sensation. The second possible origin of conscious sensation involves the relaxation of the internal anal sphincter. Internal anal sphincter relaxation arises from a local reflex of intrinsic rectoanal pathways (8), which differ from sensory pathways which require spinal nerves. The anatomic distinction explains internal anal sphincter relaxation in the presence of sensory loss. For example, patients with diabetes (3) and meningomyelocele (2) have an intact internal anal sphincter relaxation reflex to rectal distention despite impaired sensation. Perception of internal anal sphincter relaxation would
November 1986
explain a delayed sensory awareness. Three observations have led us to believe that in the 13 patients presented here, conscious sensation is related to internal anal sphincter relaxation. First, the delay in awareness of balloon distention is independent of sensory threshold. In fact, 2 of our 13 patients had nearly normal sensory volume thresholds with sensory delays of 2 and 13 s. Second, sensory recognition occurs at a reproducible level of internal sphincter relaxation in individual patients, although there is considerable variation between patients. Third, patients often are able to distinguish rectal distention from internal sphincter relaxation after retraining. They describe the awareness of rectal distention as the newly acquired sensation. Despite the attractive hypothesis of sensing internal sphincter relaxation, in some patients sensation occurs several seconds after complete internal sphincter relaxation. Retraining the patients to fecal continence was independent of the length of sensory delay. Successful retraining was not surprising as there is precedent for improvement in sensory thresholds in diabetics (3) and nondiabetics using biofeedback therapy (4). Wald and Tunuguntla (3) have proposed recruitment of adjacent neurons to mediate rectal sensation as a plausible explanation, inasmuch as the afferent pathways originally used may be damaged. Despite the failure of this and previous studies to identify the mechanism through which patients are retrained, the very rapid response mandates the utilization of existing neurologic pathways whether original or recruited. The clinical improvement in fecal incontinence in these patients depended more on improvement in the delayed recognition of balloon distention than on the specific volume sensed, as no individual continued to have fecal inconti-
FECAL INCONTINENCE AND RECTAL SENSORY DELAY
1191
nence despite a few failures to normalize the sensory threshold. In the 13 patients selected from our referral population, we discovered a new, common, and clinically important manometric abnormality of delayed sensation to rectal balloon distention. The putative cause of the sensory abnormality varied, but recognition of rectal balloon distention appeared to be secondary to internal anal sphincter relaxation. Our success in retraining sensory abnormalities supports the use of anorectal manometric techniques in the treatment of fecal incontinence.
References 1. Engel BT, Nikoomanesh P, Schuser MM. Operant conditioning
of recto sphincteric responses in the treatment of fecal incontinence. N Engl J Med 1974;290:646-9: 2. Wald A. Use of biofeedback in treatment of fecal incontinence in patients with meningomyelocele. Pediatrics 1981;68:45-9. 3. Wald A, Tunuguntla AK. Anorectal sensorimotor dysfunction in fecal incontinence and diabetes mellitus. N Engl J Med 1984;310:1282-7.
4. Cerulli MA, Nikoomanesh P, Schuster MM. Progress in biofeedback conditioning for fecal incontinence. Gastroenterology 1979;76:742-6.
5. Goldenberg DA, Hodges K, Hersh T, Jinich H. Biofeedback therapy for fecal incontinence. Am J Gastroenterol 1980; 74:342-5.
6. Read M, Read NW, Barber DC, Duthie HL. Effects of loperamide on anal sphincter function in patients complaining of chronic diarrhea with fecal incontinence and urgency. Dig Dis Sci 1982;27:807-14.
7. Whitehead WE, Orr WC, Engel BT, Schuster MM. External anal sphincter response to rectal distension: learned response or reflex. Psychophysiology 1981;19:57-62. 8. Schuster MM, Hendrix TR, Mendeloff AI. The internal anal sphincter response: manometric studies on its normal physiology, neuronal pathways, and alteration in bowel disorders. J Clin Invest 1963;42:196-207.
Delayed Rectal Sensation With Fecal Incontinence Successful Treatment Using Anorectal Manometry WILLIAM D. BUSER and PHILIP B. MINER, Jr. Department of Medicine, Division of Gastroenterology, University of Kansas Medical Center, Kansas City, Kansas
Retraining of the external sphincter response to rectal distention and improving the sensory threshold to balloon distention is documented as effective treatment for fecal incontinence in selected patients. Using anorectal manometric techniques, delayed conscious rectal sensation was demonstrated in 28% of 46 consecutive patients referred for fecal incontinence. In patients with delayed recognition of balloon distention, conscious rectal sensation seemed to correlate with a consistent level of internal sphincter relaxation rather than the primary stimulus of balloon distention of the rectum. Anorectal retraining techniques resulted in [a) correction of sensory delay of 2-22 s, [b) elimination of fecal incontinence, and [c) improved sensory threshold in 10 of 13 patients. This previously unreported sensory abnormality represents a treatable manometric abnormality identified by anorectal motility in patients with fecal incontinence. The recent investigations of the physiology of the anal sphincteric barrier have helped design retraining techniques for reestablishing bowel control in patients with fecal incontinence. Retraining techniques advocate the use of anorectal manometry to strengthen the muscular barrier and to improve sensory acuity to rectal distention. Success in treating incontinence has been achieved using rectal balloon distention to coordinate voluntary external sphincter contraction (1). Received January 22, 1985. Accepted April 23, 1986. Address requests for reprints to: Philip B. Miner, Jr., M.D., Medicine Office-4035D, University of Kansas Medical Center, 39th and Rainbow, Kansas City, Kansas 66103. The authors thank Lyn Loveland and Judy Bowsky for their nursing assistance, and Wanda Lantz for expert secretarial assistance. © 1986 by the American Gastroenterological Association 0016-5085/86/$3.50
This technique coordinates sensory impulses and voluntary muscular effort; thus, intact rectal sensation is imperative for successful retraining. The importance of sensation has been clearly documented in children with meningomyelocele (2). As reflex internal sphincter relaxation is directly proportional to the volume of balloon distention, it follows that enhancing the rectal sensory threshold to smaller balloon volumes should improve continence by modulating the strength of the anal sphincteric barrier. This has been accomplished in diabetic (3) and nondiabetic (4,5) patients with the predicted improved fecal continence. We have identified a previously unrecognized sensory deficit in 13 of 46 consecutive patients referred for fecal incontinence. These patients did not recognize that a balloon had been distended in their rectum for several seconds. This sensory delay in the time from rectal balloon distention to conscious recognition of a sensation of rectal fullness often occurred at the nadir of internal sphincter relaxation allowing the patient to recognize rectal fullness when the sphincteric barrier was the weakest. The clinical and manometric findings and the results of the retraining of the 13 patients with this previously unreported finding are presented.
Materials and Methods Between September 1983 and August 1984, 46 patients with fecal incontinence were referred for anorectal studies and entry into our retraining program. The presumed underlying causes of the fecal incontinence in these patients are listed in Table 1. Anorectal manometry was performed in all patients, whereas retraining was restricted to patients who were alert, cooperative, highly motivated, and readily able to respond to verbal commands. Although patients with severe neurologic deficits were accepted for training, most
November 1986
FECAL INCONTINENCE AND RECTAL SENSORY DELAY
Table 1. Underlying Causes in All 46 Patients Referred With Fecal Incontinence
any change in rectal sensation was emphasized. If the verbal response to balloon distention was delayed or if the volume was not sensed, the patient was rechallenged with the same volume and told when the rectal balloon was being distended. Several repetitions of this step were often required before improved awareness of rectal sensation occurred. Before decreasing the balloon volume, the patient had to respond accurately to an unsignaled stimulus. The patients usually corrected the sensory delay first and then improved the sensory threshold. The second phase of retraining was performed with the patient contracting the external sphincter in response to sensing rectal balloon distention. During the manometric session, the patient was encouraged to learn to contract the puborectalis and external anal sphincter to gain the highest pressures. Between manometry sessions the patients exercised the puborectalis and external anal sphincter muscles as directed by manometric results. Five patients were initially given low-dose loperamide (Imodium, Janssen Pharmaceutica Inc., Piscataway, N.J.) to increase internal sphincter tone (6). The patients required from one to three retraining sessions to obliterate the delay in sensation and lowering of sensory thresholds. The length of each session ranged from 15 to 30 min. Criteria for a good response to anorectal manometric retraining included (a) obliteration of the delay in sensation, (b) decrease in the sensory threshold, and (c) resolution of the fecal incontinence and the extreme urgency. The data were analyzed with the paired Student's t-test, with standard deviation used to express variation from the mean.
Medical
Surgical
Diabetes mellitus Vincristine Meningomyelocele Rectal pain Pelvic fracture Compression fracture of spine Proctitis Perineal descent Myasthenia Arthritic spine Radiation to pelvis Obstetric trauma
Hemorrhoidal repair Rectocele repair Anal repair Transurethral resection of the prostate Radical prostatectomy Laminectomy Spinal fusion L4 to S1
of the 13 patients with delayed sensation had no gross neurologic deficits (although specific neurologic testing, such as pinprick, proprioception, and tactile touch testing was not systematically done beyond the perineum). Anorectal manometry was performed using a low compliance water perfusion system (Arndorfer) with a triplelumen catheter having radially oriented ports spaced at 0.5-cm intervals. Sensory threshold, internal sphincter response, and external sphincter responses were evaluated using a 150-ml capacity balloon attached 5 cm from the distal catheter port. The balloon volume for testing sensation was infused in 2-3 s and stepped in 5-ml increments. The following measurements were made: (a) the mean maximal basal and the mean maximal squeeze pressures by station and pull-through techniques; (b) sensory threshold as defined by the smallest volume of rectal distention repeatedly (three or more times) and reproducibly (>80% accuracy) sensed by the patient; and (c) the delay in sensation, that is, the number of seconds from rectal balloon distention to conscious recognition of rectal pressure. The delay in sensation was measured by marking the tracings from complete balloon distention to the patients' verbal recognition. The patients were instructed to respond immediately to any change in rectal sensation. Initially, a large volume of air was given, usually 60 ml, to allow the patient to determine the nature of the stimulus. This volume was sensed by a majority of patients and verified their ability to respond quickly. If 60 ml was not perceived, then larger volumes were used. A small number of patients were unable to sense the maximum volume administered (150 ml) and no attempt at retraining could be started. If delayed sensation appeared to be present, the patient was rechallenged and told when the volume of air was injected to test for the ability to respond versus a delay in sensation. In all cases in which we report delayed sensation, the patient acknowledged that he did not immediately sense rectal distention. In patients found to have sensory delay, the sequence of retraining efforts was (a) obliterate the sensory delay, (b) improve anorectal sensory threshold, and (c) enhance external sphincter motor response. The patients were reinstructed in the importance of concentrating on changes of rectal sensation. Immediate verbal response to
1187
Results In the 46 consecutive patients with fecal incontinence referred for anorectal studies, welldocumented delayed rectal sensation was present in 13. These patients had no other gross neurologic abnormalities. The remaining 33 patients responded immediately to rectal distention, although several had abnormal sensory thresholds. An immediate response to rectal balloon sensation was also noted in separate groups of patients referred for constipation or perineal pain.
Clinical Data The clinical details of the 13 patients with delayed rectal sensation are presented in Table 2. The 7 women and 6 men in this group ranged in age from 13 to 66 yr. The duration of fecal incontinence varied from a few months to 23 yr (Table 2). The frequency of incontinent episodes varied from 1-2 times per month (3 patients), to daily or several times a week (7 patients), to multiple times a day (2 patients). Extreme urgency was a predominant symptom in 10 of the 13 patients. The 3 patients without a sense of urgency reported nighttime soil-
1188
GASTROENTEROLOGY Vol. 91 , NO.5
BUSER AND MINER
Table 2. Clinical Data on the 13 Patients With Delayed Conscious Rectal Sensation Severity of incontinence a
Duration of incontinence (rna)
Patient No.
Age (yr)
Sex
1 2 3
58 66 59
F M M
4
38
F
5 6
51 45
F F
1 2
8 276
7 8 9
70 13 45
M M F
1 4 2
2 156 120
10 11 12
63 63 66
M M F
3 3 3
2 120 9
13
60
F
4
5
Q
18 36 2
3 2 0 Bladder cyst 1
Underlying cause b Perineal descent, T AH, 4 LB TURF, low back pain Radical prostatectomy Laminectomy and discectomy, L4 to S1 fusion Perineal descent Rectocele and cystocele repair, hemorrhoidal surgery, 4 LB TURP and radiation to pelvis Encopresis Back injury-fall, TAH, anal tear with delivery None Vincristine Arthritic spine, bile salt catharsis Bile salt catharsis, 4 LB
4
Severity of symptoms are coded as follows : 0 = urgency only, 1 = 1-2 a month , 2 = several times a week, 3 = once a day, 4 = multiple times a day. b TAH, total abdominal hysterectomy; LB, live births ; TURP, transurethral resection of the prostate.
ing or recognized soiling only after incontinent stool had passed. One patient complained of extreme rectal urgency although he was never incontinent. A variety of underlying conditions could have been responsible for incontinence. Eight patients had more than one condition. In 1 patient no underlying condition was suggested by the history or physical examination. Eight patients had at least one relevant operation that could be implicated as a cause of the incontinence. These included a radical prostatectomy, laminectomy, and discectomy, L4 to Sl fusion, rectocele and cystocele repair, hemorrhoidal surgery, transurethral resection of the prostate (2 patients), and total abdominal hysterectomy (2 patients). Four patients had obstetrical-associated conditions, including 3 patients with multiple vaginal deliveries and 1 patient who sustained an anal tear with delivery. The 3 patients with low back pain had (1) arthritic spine, (b) injury occurring during a fall, and (c) idiopathic back pain. Other conditions noted included bile salt catharsis, previous vincristine therapy complicated by a sensory neuropathy, bladder cyst, and perineal descent (2 patients).
ter movement made accurate measurement of the percentage of internal anal sphincter relaxation at which recognition occurred technically difficult. Despite these difficulties, the percentage of internal anal sphincter relaxation at the time of recognition appeared relatively constant for each individual. 22 20 18
...... I/)
......, >as Q)
C
...>-
In this subset of 13 patients, the maximum time from balloon distention to conscious recognition ("rectal sensory delay") ranged from 2 to 22 s, with a mean of 8.7 ± 5.3 s and a median of 7 s (Figure 1). Conscious rectal sensation appeared to occur at a fixed level of internal anal sphincter relaxation. The variations in the recorder baseline and slight cathe-
14 12
0
I/)
c: 10 Q)
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Figure 1. Time from rectal balloon distention to conscious rectal sensation before and after retraining in the 13 patients with sensory delay.
FECAL INCONTINENCE AND RECTAL SENSORY DELAY
November 1986
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deviations from our normal mean. The mean maximal squeeze pressure before training was 80 ± 24 mmHg, with a median of 75 mmHg and a range of 48-130 mmHg. The mean maximal squeeze pressure increased after training to 94 ± 28 mmHg (paired Student's t-test; p < 0.005), with a median of 98 mmHg and a range of 48-130 mmHg. We consider a mean maximal squeeze pressure of 2:: 11 0 mmHg to be normal.
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Figure 2. Anorectal sensory thresholds before and after sensory retraining in the 13 patients with sensory delay. There was significant improvement in the sensory threshold after retraining (p < 0.001).
Recognition of balloon distention occurred after an internal anal sphincter relaxation of 10%-70% of the maximal basal pressure. Patients with the highest percentage of relaxation before sensation were those with the largest volume sensory thresholds. In only 1 case did we fail to document internal anal sphincter relaxation as a possible sensory stimulus. The initial volume sensory thresholds are shown in Figure 2. The minimum perceived volume ranged from 15 to 65 ml, with a mean of 39 ± 16 ml and a median of 35 ml. Wald and Tunuguntla (3) reported a mean normal sensory threshold of 12.5 ml. In our patients, we consider a sensory threshold of 15 ml or less as normal, although the mean threshold value is -10 ml. Because we determine the volume sensory threshold in 5-ml increments, the exact mean value has little importance. Sphincter pressures measured by anorectal manometry in these 13 patients are summarized as follows (Figure 3). The mean maximal basal pressure before training was 50 ± 20 mmHg, with a median of 40 mmHg and a range of 27-92 mmHg. The mean maximal basal pressure increased after training to 62 ± 23 mmHg (paired Student's t-test; p < 0.01)' with a median of 58 mmHg and a range of 38-103 mmHg. Only 10 patients were studied more than 1 mo after successful retraining. In our patients, a mean maximal basal pressure of <40 mmHg fell two standard
Twelve of the 13 patients undergoing retraining had a good response as manifested by control of the fecal incontinence and rectal urgency. The delayed sensation was corrected iIi all patients, and several patients were able subsequently to distinguish the immediate rectal sensation of balloon distention from the previous recognized sensation that occurred several seconds after rectal balloon distention (Figure 1). There was significant improvement in the sensory threshold (paired Student's t-test; p < 0.001), with 10 of 13 patients improving (Figure 2). One patient (patient 3) continued to complain of intolerable urgency without incontinence, and he was unable to improve his sensory threshold with retraining efforts. The duration of follow-up has ranged from 16 to 30 mo. 140 120
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Figure 3. Anorectal mean maximal basal pressures and mean maximal squeeze pressures before and after retraining episodes. Three patients had improved symptomatically after a single session and were not restudied. The posttraining means of both the mean maximal basal pressure and mean maximal squeeze pressure were significantly different (p < 0.01 and p < 0.005, respectively).
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BUSER AND MINER
GASTROENTEROLOGY Vol. 91. No.5
Discussion Delayed awareness of rectal balloon distention has not been described in patients with fecal incontinence. The delayed sensory awareness in conjunction with the impaired sensory threshold described in these 13 patients with fecal incontinence appears to be a common and easily treated abnormality. Several accepted causes of incontinence were present in these patients (Table 2), although perineal or pelvic injury was most common (9 of 13 patients). Successful retraining was independent of the putative cause of the fecal incontinence. No consistent features of the medical history or physical examination predicted sensory delay, although extreme urgency to defecate or the unrecognized passage of stool were common symptoms. The delay in recognition of rectal fullness and internal sphincter relaxation may explain the profound sense of urgency to defecate. The manometric findings in 1 patient (patient 7) with delayed sensation are illustrated in Figure 4. In this selected part of the motility, the perfusion port senses both internal anal sphincter relaxation and external anal sphincter contraction. The relaxation response to 30-ml balloon distention was not sensed (Figure 4A). The second motility segment shows the anal canal pressure when the patient squeezed as soon as the volume was sensed. The rapid squeeze after the 6-s delay occurs after an internal anal sphincter relaxation of about 50%. The findings after retraining are illustrated in Figure 4B. In the first section, 40 ml of air was instilled to document internal anal sphincter relaxation. The second part illustrates the voluntary response to 20 ml. The squeeze is immediate, with the slope perpendicular to the resting pressure. The final sensory threshold was 15 ml in this patient. The following sequence of events appears to occur in these patients. In the presence of impaired volume sensation and delayed awareness, fecal material enters the rectum without conscious recognition. As the rectum distends, internal anal sphincter relaxation occurs with failure of timely contraction of the external anal sphincter, resulting in a relaxed anal channel. The late recognition of volume in the rectum or the passage of stool into the anal canal gives the patient a sense of extreme urgency. With the sphincteric barrier compromised by normal reflex relaxation from a distended rectum, the attempt to overcome progressive internal anal sphincter relaxation fails, resulting in fecal incontinence with a very brief warning. These observations explain the history of very brief warning or unrecognized passage of stool, especially when the stool is solid. The delay in conscious sensation is too long to be due primarily to balloon distention. External sphinc-
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Figure 4. A. A manometric tracing from case 2 (patient 7) demonstrates the delay of conscious sensation to rectal balloon distention. The left tracing demonstrates internal sphincter relaxation to 30 ml of rectal balloon distention without conscious sensation. In the right tracing, rectal balloon distention induces internal sphincter relaxation followed 6 s later by conscious recognition and voluntary external sphincter contraction (squeeze). B. A follow-up manometric tracing 1 mo later demonstrates correction of the sensory delay. The left panel demonstrates internal sphincter relaxation to 40 ml of rectal balloon distention. The right tracing demonstrates voluntary external sphincter contraction without delay after 20 ml of rectal balloon inflation.
ter contraction could account for conscious sensation as external sphincter contraction occurs simultaneously with balloon distention and internal sphincter relaxation in normal patients. External anal sphincter contraction was absent at the time of sensation in the majority of our patients, making conscious awareness due to external sphincter contraction an unlikely possibility. Furthermore, external anal sphincter contraction may be partly dependent on cortical function (7), suggesting that external anal sphincter contraction is a result rather than a cause of sensation. The second possible origin of conscious sensation involves the relaxation of the internal anal sphincter. Internal anal sphincter relaxation arises from a local reflex of intrinsic rectoanal pathways (8), which differ from sensory pathways which require spinal nerves. The anatomic distinction explains internal anal sphincter relaxation in the presence of sensory loss. For example, patients with diabetes (3) and meningomyelocele (2) have an intact internal anal sphincter relaxation reflex to rectal distention despite impaired sensation. Perception of internal anal sphincter relaxation would
November 1986
explain a delayed sensory awareness. Three observations have led us to believe that in the 13 patients presented here, conscious sensation is related to internal anal sphincter relaxation. First, the delay in awareness of balloon distention is independent of sensory threshold. In fact, 2 of our 13 patients had nearly normal sensory volume thresholds with sensory delays of 2 and 13 s. Second, sensory recognition occurs at a reproducible level of internal sphincter relaxation in individual patients, although there is considerable variation between patients. Third, patients often are able to distinguish rectal distention from internal sphincter relaxation after retraining. They describe the awareness of rectal distention as the newly acquired sensation. Despite the attractive hypothesis of sensing internal sphincter relaxation, in some patients sensation occurs several seconds after complete internal sphincter relaxation. Retraining the patients to fecal continence was independent of the length of sensory delay. Successful retraining was not surprising as there is precedent for improvement in sensory thresholds in diabetics (3) and nondiabetics using biofeedback therapy (4). Wald and Tunuguntla (3) have proposed recruitment of adjacent neurons to mediate rectal sensation as a plausible explanation, inasmuch as the afferent pathways originally used may be damaged. Despite the failure of this and previous studies to identify the mechanism through which patients are retrained, the very rapid response mandates the utilization of existing neurologic pathways whether original or recruited. The clinical improvement in fecal incontinence in these patients depended more on improvement in the delayed recognition of balloon distention than on the specific volume sensed, as no individual continued to have fecal inconti-
FECAL INCONTINENCE AND RECTAL SENSORY DELAY
1191
nence despite a few failures to normalize the sensory threshold. In the 13 patients selected from our referral population, we discovered a new, common, and clinically important manometric abnormality of delayed sensation to rectal balloon distention. The putative cause of the sensory abnormality varied, but recognition of rectal balloon distention appeared to be secondary to internal anal sphincter relaxation. Our success in retraining sensory abnormalities supports the use of anorectal manometric techniques in the treatment of fecal incontinence.
References 1. Engel BT, Nikoomanesh P, Schuser MM. Operant conditioning
of recto sphincteric responses in the treatment of fecal incontinence. N Engl J Med 1974;290:646-9: 2. Wald A. Use of biofeedback in treatment of fecal incontinence in patients with meningomyelocele. Pediatrics 1981;68:45-9. 3. Wald A, Tunuguntla AK. Anorectal sensorimotor dysfunction in fecal incontinence and diabetes mellitus. N Engl J Med 1984;310:1282-7.
4. Cerulli MA, Nikoomanesh P, Schuster MM. Progress in biofeedback conditioning for fecal incontinence. Gastroenterology 1979;76:742-6.
5. Goldenberg DA, Hodges K, Hersh T, Jinich H. Biofeedback therapy for fecal incontinence. Am J Gastroenterol 1980; 74:342-5.
6. Read M, Read NW, Barber DC, Duthie HL. Effects of loperamide on anal sphincter function in patients complaining of chronic diarrhea with fecal incontinence and urgency. Dig Dis Sci 1982;27:807-14.
7. Whitehead WE, Orr WC, Engel BT, Schuster MM. External anal sphincter response to rectal distension: learned response or reflex. Psychophysiology 1981;19:57-62. 8. Schuster MM, Hendrix TR, Mendeloff AI. The internal anal sphincter response: manometric studies on its normal physiology, neuronal pathways, and alteration in bowel disorders. J Clin Invest 1963;42:196-207.