Study of segmental colonic transit time in healthy men.

BACKGROUND/AIMS: There are few reports of the segmental colonic transit time (SCTT) in healthy men. To clarify the SCTT for healthy men, the author measured the SCTT of healty men using radiopaque markers (RM). METHODOLOGY: The author analyzed the SCTT of 26 healthy men, who were aged from 24 to 60 years and had a mean age of 48.8 years, with RM (20 radiopaque polyvinyl chloride 0-rings). The criteria for participation included a usual stool frequency of between three per week and three per day, no history of gastrointestinal disease, and no use of medications known to affect gastrointestinal motility. RESULTS: The overall gastrointestinal transit time was 36.2±5.1 hours, and the transit time from the mouth to the cecum was 6.8±1.4 hours. The half-dose transit times of the ileocecal valve, hepatic flexure, splenic flexure, descending-sigmoid line, and evacuation were 6.9±1.6, 15.9±1.7, 18.8±1.7, 24.3±4.4 and 36.4±5.3 hours, respectively. The ascending (9.5±2.3 hours) and descending colon (5.5±4.1 hours) had shorter transit times than the sigmoid-rectum section (12.7±2.1 hours) (p<0.001, p<0.01, respectively), and the transverse colon (4.2±2.1 hours) had a shorter transit time than the ascending colon (p<0.05). There were no significant differences in transit time between the descending and transverse colon. CONCLUSIONS: Measuring the SCTT using RM may be effective for detecting the SCTT of specific sections of the bowel. This method is simple and can be easily performed at any radiology department.

Significance of defecography in the diagnosis and evaluation of male patients with defecation disorders.

BACKGROUND/AIMS: There are few reports on defecography in male patients with defecation disorders (DD) such as morphological and functional abnormalities (MFA) in the anorectal region. To clarify the significance of defecography in male patients with DD, defecography was performed in the diagnosis and evaluation of DD. METHODOLOGY: The subjects of this study included 37 male patients with DD (group A; aged 15 to 73 years, average 46.5 years). As a control (group B), 30 male healthy volunteers (aged 26 to 66 years, average 46.9 years) were also examined. To perform defecography, we used a plastic pot placed on the elevated footrest of an X-ray table, and evaluated the findings of defecography. A contrast medium (a mixture of barium and wheat flour) was infused into the rectum. RESULTS: In group A, the incidence of a sense of incomplete emptying of the rectum was significantly greater than that in patients with chronic constipation, difficulty in bowel emptying, perineal pain with defecation, and discomfort in the perineal region (p = 0.0483, p < 0.0001, p < 0.0001, p < 0.0001, respectively). The incidence of bowel habits (once per day) in group B was significantly greater than that that in group A (p < 0.0001). The incidence of defecation with straining in group A was significantly greater than that in group B (p < 0.0001). In group A, the incidences of abnormalities of the levator muscles and abnormalities of the levator muscle with abnormalities in the rectal wall were significantly greater than abnormalities of the rectal wall (p = 0.0049) and normal defecogram (p = 0.1022). The incidence of the normal defecogram in group B was significantly greater than that in group A (p < 0.0001). CONCLUSIONS: Defecography clearly showed MFA in male patients with DD. Defecography is useful for the diagnosis and evaluation of the MFA in male patients with DD.

Are there any functional differences of the enteric nervous system between jejunum and ileum in normal humans?

BACKGROUND/AIMS: Functional differences of the enteric nervous system (ENS) between the jejunum and ileum in humans are still unknown. To clarify the physiological differences of the ENS in the normal human jejunum and ileum, we investigated the enteric nerve responses on normal jejunum and normal ileum in vitro. METHODOLOGY: Twenty-two preparations of normal jejunum were taken from 22 patients with gastric cancer (14 men and 8 women, aged 43 to 65 years with a mean age of 49.0 years). Twenty preparations of normal ileum were also taken from 20 patients with right sided colonic cancer (15 men and 5 women, aged 40 to 63 years with a mean age of 50.9 years). A mechanographic technique was used to evaluate in vitro muscle responses to electrical stimulation (EFS) of adrenergic and cholinergic nerves before and after treatment with various autonomic nerve blockers. RESULTS: Responses to EFS before blockade of the adrenergic and cholinergic nerves; Muscle strips in jejunum and ileum demonstrated significant contraction reactions rather than relaxation reactions (p < 0.0001, p = 0.0001, respectively). In addition, jejunal muscle strips showed significant contraction reactions than those in ileal muscle strips (p = 0.0274). Responses to EFS after blockade of the adrenergic and cholinergic nerves; Jejunal muscle strips demonstrated relaxation reactions rather than contraction reactions by EFS (p = 0.0704). Ileal muscle strips significantly demonstrated relaxation reactions rather than contraction reactions by EFS (p < 0.0001). In addition, ileal muscle strips showed significant relaxation reactions more than those in jejunal muscle strips (p = 0.0451). Tetrodotoxin abolished the EFS responses in the muscle strips both jejunum and ileum. CONCLUSIONS: Cholinergic nerves are mainly involved in regulation of enteric nerves in the jejunum rather than the ileum. In contrast, the ileum was more strongly innervated by non-adrenergic noncholinergic inhibitory nerves than the jejunum.

Studies on pudendal nerve terminal motor latency in patients after ileal J-pouch-anal anastomosis for ulcerative colitis and adenomatous coli in childhood.

BACKGROUND/AIMS: To clarify the neurological function with respect to external anal sphincter (EAS) muscles in child patients with or without soiling after ileal J pouch anal anastomosis (IPAA), we examined the terminal motor latency in the pudendal motor nerves (PNTML). METHODOLOGY: A total of nine patients after IPAA for UC (7 cases) and AC (2 cases) were studied (6 males and 3 females, 10 to 15 with a mean age of 13.8 years). Patients one year after IPAA with soiling were also subdivided by the see page of mucous and/or stool group A (5 cases); rare soiling with loose stool, group B (4 cases); occasional soiling (1 time per 2 or 3 days). However, all patients showed continence 2 years after IPAA (Group C). Group D served as controls without gastrointestinal symptoms and digestive diseases and consisted of 12 subjects (8 males and 4 females aged 12 to 16 years old with a mean age of 14.8 years). Examinations were performed 1 and 2 years after ileostomy closure. Bilateral (left-sided and right-sided) PNTML tests were performed on all patients in order to measure the latency of the response in the bilateral EAS muscle following digitally directed transrectal pudendal nerve stimulation. RESULTS: 1) Values of the PNTML at the right-sided of the PN: The conduction delay in group B was the longest, followed by groups A, C, and D. Moreover, significant differences in PNTML were noted between groups A and B, between groups A and D, between groups B and C, and between groups B and D (p < 0.0001, p = 0.0316, p < 0.0001, p < 0.0001 respectively). There were no significance differences between group A and C or between groups C and D (p = 0.1733, p = 0.2957, respectively). 2) Values of the PNTML at the left-sided of the PN: The conduction delay in group B was the longest, followed by groups A, C, and D. Moreover, significant differences in PNTML were noted between groups A and B, between groups A and D, between groups B and C, and between groups B and D (p < 0.0001, p = 0.0584, p < 0.0001, p < 0.0001 respectively). There were no significance differences between groups A and C or between groups C and D (p = 0.3042, p = 0.2553, respectively). CONCLUSIONS: These findings support the hypothesis that child patients' soiling after IPAA may be caused by damage to the bilateral pudendal motor nerves.

A pathophysiological study using anorectal manometry on patients with or without soiling 5 years or more after low anterior resection for lower rectal cancer.

BACKGROUND/AIMS: Physiological assessments of the anorectum in patients with soiling 5 years or more after low anterior resection (LAR) are still inconclusive. The purpose of this study is to clarify the significance of anorectal functions in patients with soiling 5 years or more after LAR for lowerrectal cancer. METHODOLOGY: Thirty-eight patients after LAR for lower rectal cancer were manometrically studied and compared with 30 healthy volunteers as controls (group C; 19 men and 11 women, aged 44 to 76 with a mean age of 65.5 years). Patients after LAR were divided into 2 groups [group A; 20 patients without soiling (13 men and 7 women, aged 47 to 75 years with a mean age of 62.1 years), group B; 18 patients with soiling (12 men and 6 women, aged 51 to 77 years with a mean age of 64.8 years)]. The mean follow-up time from LAR was 67.2months (range 60-84 months). Anorectal manometry was performed on all patients in order to assess: Anal sphincter pressure at rest (ASPR; mmHg), Maximum anal sphincter pressure during voluntary contraction (MASPVC; mmHg), Minimum rectal sensory threshold volume (MRSTV; mL), Maximum rectal tolelated threshold volume (MRTTV; mL), Rectal compliance (RC; mL/mmHg), Rectoanal inhibitory reflex (RAIR), and Rectal pressure (RP; mmHg). RESULTS: The distance from the dentate line (DL) to the level of anastomosis in group B (2.2 cm) was significantly shorter than that in group A (4.1 cm) (p<0.05). ASPR in group B was significantly lower than that in groups A and C (p<0.05, p<0.01, respectively). MASPVC in group B was significantly lower than groups A and C (p<0.05, p<0.01, respectively). There were no significant differences of MRSTV among groups. MRTTV in group B was significantly lower than that in groups A and C (p<0.01, p<0.05, respectively). RC in group B was significantly lower than that in groups A and C (p<0.05, p<0.01, respectively). The frequency rate of positive RAIR in group B was significantly lower than that in groups A and C p<0.05, p<0.01, respectively). RP in group B was significantly higher than that in groups A and C (p<0.01, respectively). CONCLUSIONS: These findings support the hypothesis that soiling after LAR may be due to analsphincter and rectal dysfunctions. Increase of the RP also may cause soiling in patients after LAR. According to our studies, a length of remaining rectum 4 cm or more from the DL may be necessary to prevent soiling after LAR.

Studies on anal canal sensitivity in patients with or without soiling after low anterior resection for lower rectal cancer.

BACKGROUND/AIMS: Anal canal sensitivity is conducted by the sensory branch of the pudendal nerve. To clarify the significance of the anal canal sensitivity function in patients with soiling after low anterior resection (LAR) for lower rectal cancer, we studied the threshold of anal canal sensitivity using an anal canal sensitivity test (ACST). MATERIALS: Subjects were 23 patients, 15 men and 8 women aged 47-69 years with a mean age of 63.3 yr, divided into patients with soiling (n = 10) and patients without soiling (n = 13), compared with control subjects (n = 20; 12 men and 8 women aged 40-65 yr with a mean age of 55.6 yr). These subjects had undergone LAR at least 12-13 months(mean 12.8 months) previously, and had no preoperative or postoperative complications. METHODS: Anal canal sensitivity was measured using an ACST. Measurement points of the anal canal were divided into 2 sites: the portion just on the dentate line (DL) and the portion 1 cm below the DL. A small electric current from a constant current generator was passed between the electrodes until the patients felt a sensation often described as tingling or pulsing. The threshold of sensitivity was assessed in the upper, middle, and lower parts of the anal canal. RESULTS: In control subjects, recording at the DL site showed the best results. Anal canal sensitivity in patients with soiling was significantly lower than in patients without soiling at both sites (p < 0.0001). There were no significant differences at the site 1 cm below the DL among patients with soiling and patients without soiling. Patients with soiling showed the worst results in anal canal sensitivity at the DL. CONCLUSION: The ACST shows significantly lower sensitivity in the anal canal site of DL in patients with soiling after LAR. These findings suggest that soiling after LAR may be due to damage to the pudendal sensory nerves.

Effects of mosapride citrate on patients after vagal nerve, lower esophageal sphincter, and pyloric sphincter-preserving nearly total gastrectomy reconstructed by jejunal J pouch interposition, and postoperative quality of life.

BACKGROUND/AIMS: Vagal nerve and pylorus-preserving nearly total gastrectomy reconstructed by interposition of a jejunal J pouch (hereinafter called NTGP) is a function-preserving operation for early gastric cancer. However, some patients after NTGP have suffered from postprandial food stasis in the substitute stomach, and postprandial stasis leads to abdominal symptoms. To clarify the clinical effect of mosapride citrate (hereinafter called MS) for prevention of food stasis in the substitute stomach for patients after NTGP, we studied the clinical effects of MS before and after administration of MS. METHODOLOGY: In a total of 24 patients (18 males, 6 females; aged 44-70 years, average 58.1 years) during 5 years after NTGP for early gastric cancer (D1 lymph node dissection, curability A), the relationship between their postoperative quality of life (QOL) and emptying function of the substitute stomach (hereinafter called EFS) was compared using a radioisotope method before MS therapy and after MS therapy at an oral dose of 15mg/day for 3 months. RESULTS: The interviews showd that after MS therapy, patients had more evident appetite and ate more food with a slight increase in body weight (0.52Kg) compared with patients before MS therapy. Before and after MS therapy, patients had no early dumping symtoms, while patients after MS therapy clearly had fewer symptoms such as reflux esophagitis, nausea, and abdominal pain compared with before MS therapy. After MS therapy, patients also had significantly decreased abdominal fullness compared with before MS therapy (p = 0.0046). Endoscopically, we found reflux esophagitis in 4 patients before MS therapy but in no patients after MS therapy. All patients before MS therapy showed residual contents in the substitute stomach, but only 10 patients after MS therapy showed residual contents in the substitute stomach. There was a significant difference between before and after MS therapy (p = 0.0016). Regarding EFS, the time to 50% residual rate before MS therapy (98.7 +/- 13.0 min) was significantly slower than that after MS therapy (83.2 +/- 13.8 min) (p = 0.0134). After MS therapy (37.0 +/- 4.9%), the residual rates at 120 minutes were significantly decreased compared with patients before MS therapy (44.8 +/- 5.3%) (p = 0.0028). Patients after MS therapy clearly had improved stasis of substitute stomach compared with before MS therapy. CONCLUSIONS: It was considered that MS therapy subsequently improves abdominal fullness due to the postprandial food stasis in the substitute stomach, contributing to the improvement of QOL of patients after NTGP.

Are there any functional differences of enteric nervous system between the proximal and distal parts from the dentate line in the normal human internal anal sphincter?

BACKGROUND/AIMS: To clarify the functional differences of the enteric nervous system in the human internal anal sphincter (IAS) between the proximal and distal parts from the dentate line, we investigated the enteric nerve responses of normal proximal and distal IAS in vitro. METHODOLOGY: Normal IAS specimens derived from 20 patients with lower rectal cancer (14 men and 6 women aged from 48 to 77 years, average 66.5 years) were used. These IAS muscles were divided into 2 parts [oral site IAS from dentate line; proximal part (PIAS; n=20), anal site IAS from dentate line; distal part (DIAS; n=20)]. A mechanographic technique was used to evaluate in vitro muscle strip responses to electrical field stimulation (EFS) before and after treatment with various autonomic nerve blockers. RESULTS: 1) Response to EFS before blockade of the adrenergic and cholinergic nerves: In PIAS, the incidence of relaxation reactions was greater than that of contraction reactions (p=0.2059). In DIAS, the incidence of contraction reactions was significantly greater than that of relaxation reactions (p=0.0001). The percentage of relaxation responses in the PIAS was significantly greater than that in the DIAS (p=0.0098). 2) Response to EFS after blockade of the adrenergic and cholinergic nerves: In PIAS, the incidence of relaxation reactions via NANC inhibitory nerve was significantly greater than that of contraction reactions via NANC excitatory nerves (p< 0.0001). In DIAS, the incidence of relaxation reactions via NANC inhibitory nerve was greater than that of contraction reactions via NANC excitatory nerves (p=0.2059). The percentage of relaxation responses via NANC inhibitory nerves in the PIAS was significantly greater than that in the DIAS (p=0.00284). 3) EFS responses in the PIAS and DIAS were blocked by tetrodotoxin. CONCLUSIONS: There are functional differences in the regulation of the enteric nervous system between the PIAS and DIAS. Contraction reaction via excitatory nerves, especially cholinergic nerves, was mainly involved in the regulation of enteric nerve responses to EFS in the DIAS. Relaxation reaction via inhibitory nerves, especially NANC inhibitory nerves, was mainly involved in the regulation of enteric nerve responses to EFS in the PIAS.

The effects of neurotensin in the colon of patients with slow transit constipation.

BACKGROUND/AIMS: The cause of dysmotility in the colon of patients with slow transit constipation (STC) is still unknown. Neurotensin (NT) has recently been shown to be a neurotransmitter in the non-adrenergic non-cholinergic (NANC) excitatory nerves of the human alimentary tract. To clarify the physiological significance of NT in the colon of patients with STC, we examined the enteric nerve responses in lesional and normal bowel segments derived from patients with STC and patients who underwent colon resection for colonic cancers. METHODOLOGY: Twenty-eight preparations were taken from colonic lesions in 10 patients with slow transit constipation (2 men and 8 women, aged 23 to 70 years, mean 46.3 years). Forty-six preparations were taken from the normal colons of 16 patients with colonic cancer (8 men and 8 women, aged 40 to 66 years, mean 50.1 years). A mechanographic technique was used to evaluate in vitro muscle responses to electrical field stimulation (EFS) before and after treatment with various autonomic nerve blockers and NT. RESULTS: After blocking both the adrenergic and cholinergic nerves (Experiment 1), NT showed contraction reaction on both normal and STC colons in a concentration-dependent manner. The contraction reactions to NT in the normal colon were more dominant than those in the STC colon. There were significant differences between the frequency of contraction reactions to NT in normal colon strips and those in STC colon strips (P < 0.001). Following addition of tetrodotoxin (Experiment II), all muscle strips of normal and STC colons demonstrated contraction responses by NT. The effects of NT in the normal and STC colon muscle strips were essentially the same as in experiment 1, although the extent of contraction was somewhat diminished. CONCLUSIONS: Those results suggested that NT acts both via NANC excitatory nerves and also directly on the colonic smooth muscle. A decrease of NT mediates NANC excitatory nerves and plays an important role in the dysmotility observed in the colons of patients with STC.

Regulation of enteric nervous system in the proximal and distal parts of the normal human pyloric sphincter--in vitro study.

BACKGROUND/AIMS: The structure of the pyloric sphincter (PS) muscle has recently been shown to divide into two parts (proximal and distal parts). To clarify the functional differences in the human PS between proximal and distal parts, we investigated the enteric nerve responses in normal proximal and distal PS specimens. METHODOLOGY: Normal PS specimens derived from 20 patients with early gastric cancer (13 men and 7 women aged from 50 to 64 years, average 58.2 years) were used. These PS muscles were divided into 2 parts [1/2 oral site of PS; proximal part (PPS; n=26), 1/2 anal site of PS; distal part (DPS; n=24)]. A mechanographic technique was used to evaluate in vitro muscle strip responses to electrical field stimulation (EFS) before and after treatment with various autonomic nerve blockers. RESULTS: Findings were: (1) Response to EFS before blockade of the adrenergic and cholinergic nerves: Excitatory responses (contraction reaction) via cholinergic nerves in the PPS were regulated more predominantly than in the DPS. Inhibitory responses (relaxation reaction) via adrenergic nerves in the DPS were regulated more predominantly than in the PPS. (2) Response to EFS after blockade of the adrenergic and cholinergic nerves: Excitatory responses (contraction reaction) via non-adrenergic non-cholinergic (NANC) excitatory nerves in the PPS were regulated significantly more than in the DPS (P = 0.0439). Inhibitory responses (relaxation reaction) via NANC inhibitory nerves in the DPS were also regulated significantly more than in the PPS (P = 0.0439). (3) EFS response in the pylorus was blocked by tetrodotoxin. CONCLUSIONS: There are differences between the PPS and DPS in the regulation of the enteric nervous system. Contraction reaction via excitatory nerves, especially cholinergic nerves, was mainly involved in the regulation of enteric nerve responses to EFS in the PPS. Relaxation reaction via inhibitory nerves, especially NANC inhibitory nerves, was mainly involved in the regulation of enteric nerve responses to EFS in the DPS.

Role of recombinant human glicentin in the normal human jejunum: an in vitro study.

BACKGROUND/AIMS: Glicentin (GL) is known as an inhibitory factor for alimentary tract movement and the possibility that GL may be a neuromodulator of the non-adrenergic non-cholinergic (NANC) inhibitory nerves has been reported from animal experiments. Since sufficient amounts of GL have not been available for the physiological studies, there is no report concerning the effects of GL on the enteric nervous system in the normal human small intestine. Recently synthesized recombinant human GL (rh-GL) has become available to study the physiological action of GL. To clarify the physiological significance of GL in the normal human small intestine, enteric nervous responses to GL in the normal small bowel were investigated. METHODOLOGY: Normal jejunal muscle strips (thirty-two preparations) derived from patients who underwent jejunal resection for advanced gastric cancers (14 cases) were used. The subjects consisted of 10 men and 4 women, aged from 48 to 66 years with a mean age of 59.9 years. A mechanographic technique was used to evaluate the in vitro jejunal muscle responses to GL (recombinant human GL; rh-GL) of adrenergic and cholinergic nerves before and after treatment with various autonomic nerve blockers. All muscle strips used in this study reacted to the electrical field stimulation (EFS), which was thus suitable for stimulation of enteric nervous system. RESULTS: In experiment I (the responses to rh-GL after blockade of the adrenergic and cholinergic nerves) the inhibition reaction ofjejunal contraction movement was concentration-dependent; 0% at 1 x 10(-9) g/mL, 6.3% at 1 x 10(-8) g/mL, 12.5% at 1 x 10(-7) g/mL, and 43.8% at 1 x 10(-6) g/mL. The remaining muscle strips demonstrated no reaction to rh-GL. In addition, significant differences were noted between 1 x 10(-9) and 1 x 10(-6) g/mL, between 1 x 10(-8) and 1 x 10(-6) g/mL, and between 1 x 10(-7) and 1 x 10(-6) g/mL (P=0.0005, P=0.0066, P=0.0359, respectively). Rh-GL concentration-dependently inhibited a contraction reaction after blockade of the adrenergic and cholinergic nerves. In experiment II (responses to rh-GL following administration of tetrodotoxin) tetrodotoxin did not block the inhibition of contraction reaction in response to rh-GL in the human jejunum. Inhibition reaction of contraction movement was seen in the jejunal muscle strips, as in experiment I. CONCLUSIONS: GL plays an important role in the regulating inhibition of the contraction reaction in normal human jejunum via NANC nerves, and has a direct action on the jejunal muscle receptor.

Assessments of anal canal sensitivity in patients with soiling 5 years or more after colectomy, mucosal proctectomy, and ileal J pouch-anal anastomosis for ulcerative colitis.

INTRODUCTION: To clarify the significance of anal canal sensitivity contribution to soiling in patients after ileal J pouch-anal anastomosis (IPAA) for ulcerative colitis (UC), we studied the sensory function of the anal canal. METHODS: Forty patients with UC who had undergone IPAA with ileostomy closure at least 60 to 132 months (mean 103.6 months) previously, and who had no preoperative or postoperative complications were recruited. They were divided into two groups: group A [n = 26; patients without soiling (16 males, 10 females; ages 15-49 years, mean 36.6 years)] and group B [n = 14; patients with soiling (10 men, 4 women; ages 24-56 years, mean 40.9 years)] compared with group C [n = 28; control subjects (18 men, 10 women; aged 19-49 years, mean 38.5 years)]. Patients with soiling were also divided into three groups (B1, rare soiling; B2, occasional soiling; B3, frequent soiling). The anal canal sensitivity threshold was measured using an anal canal electrosensitivity test (ACEST). The measurement point of anal canal was divided into three parts: lower part [1 cm below the dentate line (DL), middle part (just on the DL), and upper part (1 cm above the DL]. A small electric current from a constant-current generator was passed between the electrodes until the patient felt a sensation often described as tingling or pulsing. The threshold of sensitivity was assessed in the upper, middle, and lower parts of the anal canal. RESULTS: In patients of group C, recording at the middle part of the anal canal showed the best results. The anal canal sensitivity threshold of group B was significantly higher than those of groups A and C at the upper and middle parts (P < 0.0001, respectively). There were no significant differences at the lower part among groups. The anal canal sensitivity threshold of subgroup B3 was significantly higher than those of groups B1 or B2 at both the upper part (P = 0.0002, P = 0.0038, respectively) and middle part (P = 0.0001, P = 0.0480, respectively). There were no significant differences at the lower part among groups. CONCLUSIONS: The ACEST shows significantly lower sensitivity in the proximal and middle anal canal in IPAA patients with soiling.

Pudendal nerve terminal motor latency in patients with or without soiling 5 years or more after low anterior resection for lower rectal cancer.

BACKGROUND: To clarify the neurological function with respect to external anal sphincter (EAS) muscles in patients with or without soiling after low anterior resection (LAR) for lower rectal cancer, we examined the terminal motor latency in the pudendal motor nerves (PNTML). MATERIALS AND METHODS: Thirty-eight patients after LAR for lower rectal cancer were studied electrophysiologically and compared with 30 healthy volunteers as controls (19 men and 11 women, aged 44 to 76 years of age, with a mean age of 65.5 years). Patients after LAR were divided into two groups [18 patients with soiling (12 men and 6 women, aged 51 to 77 years with a mean age of 64.8 years), 20 patients without soiling (13 men and 7 women, aged 47 to 75 years with a mean age of 62.1 years)]. The mean follow-up time from LAR was 67.2 months (range 60-84 months). Bilateral (left-sided and right-sided) PNTML tests were performed on all patients in order to measure the latency of the response in the bilateral EAS muscle following digitally directed transrectal pudendal nerve stimulation. RESULTS: The distance from the anal verge to the level of anastomosis in patients with soiling (mean, 2.2 cm) was significantly shorter than that in patients without soiling (mean, 4.1 cm) (P < 0.05). Conduction delay of the bilateral PNTML in patients with soiling was longer than that in patients without soiling and normal subjects, significantly (P < 0.01, respectively). There was no significant difference between the right-sided and left-sided PNTML. CONCLUSIONS: These findings support the hypothesis that soiling after LAR may be partially caused by damage to the bilateral pudendal motor nerves.