Modifizierte Methode zur Bestimmung der linksseitigen Pudenduslatenz

The standard St. Mark’s pudendal electrode is used to determine pudendal nerve terminal motor latency (PNTML). Only by stimulation of and leads from the right pudendal nerve we get a well reproductible potential with a negative recording, since the different and indifferent recording electrodes are attached to the base of the finger on the right and left side, and it’s impossible to change them. This methodical deficit can easily be resolved by reversing the lead electrodes via adapter. Using this modified lead, we found significantly better identifiable latencies in 37 (74%) of the 50 patients we studied. With the previous method, latency in 5 cases was in range of 0.2 ms not clearly defined; in 18 cases latency varied around 0.3 ms; in the remaining 14 cases by more than 0.3 ms. Furthermore we found an increase of the amplitude in all examined cases.     

Fistula in ano surgery has no impact on pudendal nerve terminal motor latency

Background Anal fistula surgery is recognized as a major risk factor for anal incontinence. This incontinence is mainly due to surgical sphincter lesions, although a neurogenic mechanism through damage to the pudendal nerve is not excluded. The objective of our study was to evaluate the influence of anal surgery on the anal terminal motor latency of the pudendal nerve (PNTML).Materials and methods The PNTML values were measured pre- and postoperatively, respectively, in 33 patients (28 men, 5 women) treated for anal suppuration and 34 patients (21 men, 13 women) undergoing pedicular hemorrhoidectomy using the Milligan and Morgan technique.Results The average age was 49.6 years in the hemorrhoid group and 45 years in the fistula group (p=0.19). There was no difference in the sex ratio between the two groups (p=0.06). In the anal fistula group, the preoperative mean PNTML was 2.42 (±0.46) ms on the infected side and 2.40 (±0.42) ms on the healthy side, with a significant difference from the control group's preoperative ipsilateral latencies: 2.73 (±0.60) ms (p=0.02, p=0.01). The variations in the postoperative PNTML of the fistula group, both on the healthy side (ΔPNTML=0.06±0.42 ms) and on the diseased side (ΔPNTML=0.03±0.40 ms), are comparable with those of the hemorrhoid group (ΔPNTML=0.01±0.48 ms; p=0.63, p=0.84).Conclusion The nervous conduction of the pudendal nerves does not seem to be altered by the presence of an infectious process in the ischiorectal fossa nor by the surgical procedure. However, a more refined electrophysiological study would seem to be necessary to assess the repercussions on the perineal innervation.F. Daniel and C. Thomas contributed equally to this work.     

Variation in pudendal nerve terminal motor latency according to disease

PURPOSE: The aims of this study were first to establish whether any difference among pudendal nerve terminal motor latency (PNTML) values exists relative to diagnosis, second to determine whether left and right latencies are similar, and third to assess any correlation between age and neuropathy. Latency was elicited three times on each side, and an average latency was recorded as a result. MATERIALS AND METHODS: Between June 1989 and April 1995, 1,026 patients (775 females and 251 males) underwent PNTML study. These patients were divided into four groups according to diagnosis: Group I, fecal incontinence; Group II, chronic constipation; Group III, idiopathic rectal pain; Group IV, rectal prolapse. Overall mean age was 61.5 (range, 6–95) years. Student's t-test was used to calculate statistical differences. Patients were then analyzed according to age and gender. Correlation was calculated with the nonparametric Mann-Whitney U test. RESULTS: Unilateral or bilateral prolongation of PNTML was noted in 90 patients (21.2 percent) in Group I, 80 (20.4 percent) in Group II, 22 (18.1 percent) in Group III, and 38 (42.6 percent) in Group IV. Average PNTML on the left side was 1.88 ms in Group I, 1.94 ms in Group II, 1.98 ms in Group III, and 2.12 ms in Group IV. Average PNTML on the right side was 1.85 ms in Group I, 1.94 ms in Group II, 1.99 ms in Group III, and 2.07 ms in Group IV. The only statistically significant differences in PNTML were between Groups I and IV (left,P <0.005; right, <0.05) and between females and males ( P <0.0001). CONCLUSION: There is no statistically significant difference between latencies of left and right pudendal nerves. Similarly, there are no statistically significant differences among patients with fecal incontinence, chronic constipation, or chronic idiopathic rectal pain. Normal latency can be expected in patients with constipation or fecal incontinence. However, patients with rectal prolapse have a more prolonged PNTML. Age is correlated with a higher incidence of pudendal neuropathy. This study reveals significant overlap among PNTML values and diagnosis.     

Pudendal nerve terminal motor latency influences surgical outcome in treatment of rectal prolapse

Purpose: This study was undertaken to document the effect of pudendal nerve function on anal incontinence after repair of rectal prolapse. METHODS: Patients with full rectal prolapse (n=24) were prospectively evaluated by anal manometry and pudendal nerve terminal motor latency (PNTML) before and after surgical correction of rectal prolapse (low anterior resection (LAR; n=13) and retrorectal sacral fixation (RSF; n=11)). RESULTS: Prolapse was corrected in all patients; there were no recurrences during a mean 25-month follow-up. Postoperative PNTML was prolonged bilaterally (>2.2 ms) in six patients (3 LAR; 3 RSF); five patients were incontinent (83 percent). PNTML was prolonged unilaterally in eight patients (4 LAR; 4 RSF); three patients were incontinent (38 percent). PNTML was normal in five patients (3 LAR; 2 RSF); one was incontinent (20 percent). Postoperative squeeze pressures were significantly higher for patients with normal PNTML than for those with bilateral abnormal PNTML (145 vs.66.5 mmHg; P =0.0151). Patients with unilateral abnormal PNTML had higher postoperative squeeze pressures than those with bilateral abnormal PNTML, but the difference was not significant (94.8 vs.66.5 mmHg; P=0.3182). The surgical procedure did not affect postoperative sphincter function or PNTML. CONCLUSION: Injury to the pudendal nerve contributes to postoperative incontinence after repair of rectal prolapse. Status of anal continence after surgical correction of rectal prolapse can be predicted by postoperative measurement of PNTML.Read at the meeting of The American Society of Colon and Rectal Surgeons, Seattle, Washington, June 9 to 14, 1996.     

Unilateral pudendal neuropathy

PURPOSE: Obstetric trauma and excessive defecatory straining with perineal descent may lead to pudendal neuropathy with bilateral increase in pudendal nerve terminal motor latencies (PNTML). We have frequently observed unilateral prolongation of PNTML. Diagnostic and therapeutic implications of unilateral pudendal neuropathy are discussed. METHODS: Records of 174 patients referred to pelvic floor laboratory for anorectal manometry and PNTML testing were reviewed. Computerized anal manometry was performed using dynamic pressure analysis, and PNTML was determined using a pudendal (St. Mark's) electrode. RESULTS: No response was elicited from pudendal nerves to electric stimulation from both sides in 14 patients (8 percent) and from one side in 24 patients (13.8 percent). Bilateral PNTML determination was possible in only 136 patients (78 percent), of whom 83 patients (61 percent) had no evidence of neuropathy, revealing normal PNTML on both sides. Of 53 patients (39 percent) with delayed conduction in pudendal nerves, in 15 patients (28 percent), PNTML was abnormally prolonged on both sides, with an abnormal mean value for PNTML. In the remaining 38 patients (72 percent), PNTML was abnormal on one side: in 27 patients with an abnormal mean PNTML and in 11 patients with a normal mean PNTML. CONCLUSIONS: A significant number of patients with pelvic floor disorders have only unilateral pudendal neuropathy. Patients with unilaterally prolonged PNTML should be considered to have pudendal neuropathy, despite normal value for mean PNTML. This fact may be relevant in planning surgical treatment and in predicting prognosis of patients with sphincter injuries.Read in part at the meeting of the New England Society of Colon and Rectal Surgeons, Brewster, Massachusetts, April 21 to 22, 1995.     

Pudendus-SSEP in der Diagnostik anorektaler Funktionsstörungen

Electrophysiological examinations in differential diagnosis of anorectal functional disorders comprise electromyogram of the pelvic floor, pudendal nerve terminal motor latency (PNTML) and evaluation of cortical latency of P 40 (pudendal SSEP). Pudendal SSEP usually is done via penile stimulation, since it is technically easier to carry out than perianal stimulation. In our study we compared latencies of P 40 in penile and perianal pudendal-SSEP. We examined 40 subjects aged 34 to 72 years (mean 52.4 years) without any manifestation of a neurological, urological or proctological disease. The stimulus was administered using penile ring electrodes at the base of the penis and the penile shaft as well as a perianal surface electrode applied at right and left lateral position. Cortical latencies were evoked using the averaging method from 500 stimuli. Cortical latencies of P 40 after perianal stimulation (mean: 36.7 ms from the right, 36.9 from the left) on the average were 4.7 ms shorter than after penile stimulation (mean: 41.5 ms), a correlation to the age of the subjects was not seen. There was also only a low correlation between the latencies of penile and perianal responses within the subjects. In conclusion, our results underline the necessity of separate normal values for penile and perianal pudendal SSEP in the differential diagnosis of anorectal functional disorders. Especially when a lesion of the afferents is assumed, the evaluation of pudendal SSEP may provide valuable additional information in combination with the more common methods such as electromyogram of the anal sphincter and PNTML.     

Electrophysiologic assessments in pudendal and sacral motor nerves after ileal J-pouch-anal anastomosis for patients with ulcerative colitis and adenomatosis coli

PURPOSE: To clarify neurologic function with respect to external anal sphincter and puborectalis muscles after J configuration ileal J-pouch-anal anastomosis for patients with ulcerative colitis and adenomatosis coli, we examined the terminal motor latency in the pudendal and sacral motor nerve (S2-4). METHODS: Latency of the response in the external anal sphincter muscle following digitally directed transrectal pudendal nerve stimulation (PNTML) and in the puborectalis muscle following transcutaneous magnetic stimulation of the cauda equina at the levels S2-4 (SMNLTSS) were measured in 12 patients with ileal J-pouchanal anastomosis; they were divided into a group with continence (7 cases) and a group with soiling (5 cases). Results were compared with data obtained from 12 patients before operation and 15 controls. RESULTS: Conduction delay of PNTML and SMNLTSS in patients with soiling was longest, followed by delay in those without any soiling, then delay in patients before operation, and then controls. In addition, significant differences were also noted between conduction delay of PNTML in controls and those who are incontinent and experience soiling (P < 0.05 and P < 0.01, respectively), and there were significant differences also noted between conduction delay of PNTML in patients before operation and those who are incontinent and experiencing soiling (P < 0.05 and P < 0.01, respectively). Conduction delay of PNTML and SMNLTSS were found in patients before operation rather than in controls. No significant differences were noted between conduction delay of PNTML and SMNLTSS in patients before operation and controls. Significant differences were also noted between conduction delay of PNTML and SMNLTSS in patients who are incontinent and experiencing soiling (P < 0.01, respectively). CONCLUSION: These findings support the hypothesis that soiling after this procedure may be partially caused by damage to pudendal and sacral motor nerves (S2-4).Read at the meeting of The Japan Society of Coloproctology, Kobe, Japan, September 24 to 26, 1994.     

Prevalence of pudendal neuropathy in fecal incontinence

PURPOSE: A prospective study was made of the prevalence and associations of pudendal neuropathy in 96 patients with fecal incontinence (72 females and 24 males). METHODS: Clinical exploration, perineal level measurement, anorectal manometry, and electrophysiologic evaluations (pudendal nerve terminal motor latency (PNTML) and external sphincter fiber density (FD)) were performed. RESULTS: Pudendal neuropathy (defined as PNTML>2.2 ms or FD>1.65) was found in 67 patients (69.8 percent) and was more common in females (75 percent) than in males (50 percent;P = 0.05). Pudendal neuropathy was also more frequent in patients with pathologic perineal descent (85 percent vs. 55 percent;P <0.01) or exhibiting risk factors such as difficult labor or excessive defecatory straining (P <0.01). Perineal level at straining correlated inversely with both PNTML and FD (P <0.01). Manometric findings suggested greater external anal sphincter damage in patients with pudendal neuropathy than in those suffering fecal incontinence but no neuropathy (P <0.05). Pressure caused by the striated anal sphincter was also inversely correlated to PNTML. Pudendal neuropathy was encountered in 37 of 63 (58.7 percent) patients with sphincter injury vs.in 31 of 33 (93.9 percent) patients with idiopathic fecal incontinence (P < 0.01). CONCLUSIONS: Pudendal neuropathy is an etiologic or associated factor often present in patients with fecal incontinence. In this sense, clinical, perineometric, and manometric findings correlate with pudendal neuropathy, though such explorations do not suffice to detect it.Read at the meeting of The American Society of Colon and Rectal Surgeons, Orlando, Florida, May 8 to 13, 1994.     

Audit of postanal repair in the treatment of fecal incontinence

PURPOSE: The short-term results of postanal repair for idiopathic fecal incontinence are satisfactory but data on long-term outcome are lacking. This study was carried out to document the short-term and long-term results of this operation and to determine whether preoperative tests predict long-term outcome. METHODS: Thirty-six patients (33 females; mean age, 57 years) with major idiopathic fecal incontinence operated on by one surgeon were studied. Patients had resting and voluntary contraction anal pressures and pudendal nerve terminal motor latencies (PNTML) measured preoperatively. Symptoms were evaluated at 6 months after operation and again at a median of 25 (range, 6–72) months in all 36 patients. Symptoms were classified as: Group C, no improvement or worse; Group B, minor improvement; and Group A, marked improvement in comparison to the patient's preoperative symptoms. Seventeen patients had postoperative physiology performed. RESULTS: At 6 months there were 6 (17 percent) patients in Group C, 12 (33 percent) in Group B, and 18 (50 percent) in Group A. At final follow-up there were 17 (47 percent) in Group C, 9 (25 percent) in Group B, and 10 (28 percent) in Group A. Comparison of the preoperative data in the final outcome groups showed (mean±SE): Groups A and B vs.Group C-resting pressure, 24.6±6 cm H ₂ O vs.40.5±12.2 (P=0.2), voluntary contraction pressure, 23.7±5.7 vs.11.8±3.6 (P=0.09), and PNTML, 3.2±0.75 mS vs.3.3±0.99 (P=0.8). Mean differences between postoperative and preoperative results were: resting pressure, 28±8.2 cm H ₂ O (P=0.003); voluntary contraction pressure, 19.5±6.7 (P=0.01); and PNTML, –0.3±0.29 mS (P=0.3). CONCLUSIONS: At 6 months 83 percent of patients had obtained some benefit from postanal repair but only 53 percent maintained this improvement with only 28 percent being markedly better. There was a trend toward a more favorable outcome in patients with greater squeezing pressures preoperatively but other tests were not of long-term predictive value.Presented in part in abstract form at the meeting of the British Society of Gastroenterology, Spring 1992.     

Prospective comparative study of abnormal distal rectoanal excitatory reflex,pudendal nerve terminal motor latency,and single fiber density as markers of pudendal neuropathy

PURPOSE: This study was undertaken to determine the role of abnormal distal rectoanal excitatory reflex (RAER) as a marker of pudendal neuropathy and to compare results with pudendal nerve terminal motor latency (PNTML) and single fiber density (SFD) estimation. METHODS: Fifteen female patients (mean age, 47.1 (range, 20–70) years) referred to the pelvic floor laboratory with pelvic floor disorders (fecal incontinence, 13 patients; constipation, 2 patients) were evaluated prospectively with neurophysiologic tests and balloon reflex manometry for evidence of pudendal neuropathy. RESULTS: Pudendal nerve terminal motor latency provided evidence of pudendal neuropathy in ten patients (67 percent) and was normal in five patients (33 percent). Increased SFD confirmed denervation of the external anal sphincter in 12 patients (80 percent), being normal in 3 patients (20 percent). Distal RAER was abnormal in 13 patients (87 percent) and was normal in 2 patients (13 percent). In ten patients (67 percent), the three diagnostic modalities were in complete agreement, correctly identifying neuropathy in nine patients (60 percent) and excluding nerve damage in one patient (7 percent). Distal RAER was normal despite prolonged PNTML and increased SFD in one patient (7 percent). In two patients (13 percent), distal RAER was abnormal or absent despite normal PNTML and SFD. Pudendal nerve terminal motor latency was normal in the presence of abnormal distal RAER and increased SFD on electromyography in two patients (13 percent). CONCLUSIONS: Abnormal distal RAER compares favorably with current neurophysiologic tests used to diagnose pudendal neuropathy.     

Magnetic stimulation of the pudendal nerve

Electroneurography of the pudendal nerve is extremely important in the diagnosis of neurogenic fecal incontinence and a pudendal canal syndrome. PURPOSE: The aim of this study was to determine pudendal nerve motor latency of the overall distance by stimulation of nerve root S3 by discharging a magnetic coil. METHODS: This can be achieved by positioning an earth electrode between the site of stimulation and the registration electrode. We investigated 18 volunteers by this method. RESULTS: The average latency period was 2.51 milliseconds (SD=0.32) on the right and 2.49 milliseconds (SD=0.33) on the left side. CONCLUSION: This method enables precise diagnosis in neuropathies of the pudendal nerve more so than with conventional electric stimulation.Presented in part at the XIIIth International Congress of EEG and Clinical Neurophysiology, Vancouver, Canada, August 30-September 8, 1993.     

Distal rectoanal excitatory reflex: A reliable index of pudendal neuropathy?

PURPOSE: Denervation of the extrinsic anal sphincter and pudendal neuropathy are confirmed by electrophysiologic or electromyographic testing, techniques that may not be available universally and require special equipment and training. A simple manometric test that is easy to perform and complements existing studies was performed to confirm pudendal neuropathy. METHODS: Fourteen patients with excessive defecatory straining and 30 patients with idiopathic fecal incontinence were studied by electrophysiology and balloon reflex manometry. Pudendal nerve terminal motor latency (PNTML) and rectoanal excitatory reflex were evaluated for abnormalities. Results were compared with 20 controls who had no anorectal complaints and who had similar testing performed. RESULTS: In controls, PNTML was normal in all but one person. Rectoanal excitatory reflex could be elicited in all controls with either 20 or 40 ml of air. Four different types of balloon reflex responses were observed in patient groups: diminutive excitation, delayed excitation, excitation at high volume of distention only, and absent excitation. Ten patients with fecal incontinence had normal PNTML but abnormal distal excitatory reflex, 5 patients had abnormal PNTML but normal distal excitatory reflex, and 15 patients had both PNTML and excitatory reflex that were abnormal. In patients with excessive defecatory straining, results of both tests were abnormal in six patients, and eight patients had abnormal excitatory reflex but normal PNTML. CONCLUSION: Pudendal neuropathy may result in abnormalities of excitatory reflex morphology or other characteristics. Abnormal distal excitatory reflex may complement electrophysiologic findings or may serve as a suitable alternative to confirm pudendal neuropathy in centers where facilities for formal testing are not available.Read in part at the meeting of the New England Society of Colon and Rectal Surgeons, Bolton Landing, New York, September 30 to October 1, 1994.     

Pudendal nerve "complete" motor latencies at four different levels in the anal sphincter system in young adults

PURPOSE: Pudendal nerve complete motor latency, or the sum of the conduction time from the root of the sacral nerve to the end of the pudendal nerve and the synaptic delay, varied in length (from shortest to longest) in the puborectalis, the deep external anal sphincter, and the superficial/subcutaneous external anal sphincter, in that order, for middle-aged people. The aim of this study was to elucidate whether such a phenomenon was physiologic or pathologic. METHODS: In 20 young adults (21.9 ± 1.37 years old, 10 females), pudendal nerve complete motor latencies were measured after magnetic stimulation to the sacral region. Electromyographic recordings were taken at depths of 5, 3.8, 2.6, and 1.5 cm from the perineal skin using a needle electrode and at 3 cm from the anal verge using surface electrodes within the anal canal. The data were compared with the data of the middle-aged cohort (65.4 ± 7.70 years old) in our previous study. RESULTS: The pudendal nerve complete motor latencies were 3.85 ± 1.24 ms at 5 cm, 3.97 ± 1.25 ms at 3.8 cm, 5.41 ± 2.42 ms at 2.6 cm, 9.98 ± 4.01 ms at 1.5 cm, and 3.45 ± 0.52 ms while using surface electrodes. The pudendal nerve complete motor latencies at 5, 3.8, and 2.6 cm were significantly shorter in the young adults than in the middle-aged subjects. The pudendal nerve complete motor latency using surface electrodes was significantly shorter than the pudendal nerve complete motor latency at 2.6 and 1.5 cm (mean ± standard deviation). CONCLUSIONS: Because pudendal nerve complete motor latency was progressively longer at 5, 3.8, 2.6, and 1.5 cm, in that order, in young adults as well as in middle-aged people, this phenomenon was considered to be physiologic and may be mechanically reasonable and safe in shutting the anal canal and might be useful for milking the residual mucus out of the anal canal to prevent soiling. Aging disturbed the innervation of the upper three levels of the anal sphincter system. Pudendal nerve complete motor latency using intra-anal surface electrodes approximated that at the highest of the anal sphincters.     

Pudendal nerve terminal motor latency in evaluation of evacuatory disorder following low anterior resection for rectal carcinoma

BACKGROUND/AIMS: Pudendal neuropathy is one of the causative factors for soiling following restorative proctocolectomy. However, there has been no report clarifying the impact of sphincter-preserving operation for colorectal carcinoma on the pudendal nerve and its relation to postoperative evacuatory disorder. METHODOLOGY: Twenty-three consecutive patients undergoing resection for rectal or sigmoid colon carcinoma were assessed with patient questionnaire, anorectal manometry, and pudendal nerve terminal motor latency study (PNTML) before and 6 months after surgery. RESULTS: Eleven patients (48%) had postoperative evacuatory disorder. The prevalence of lower anastomosis was significantly higher in the evacuatory disorder group. In manometry, maximum tolerable volume and neorectal capacity were significantly smaller in the evacuatory disorder group than in the nonevacuatory disorder group. Manometric study showed no difference between the two groups in terms of postoperative anal squeezing pressure, which is generated by the external anal sphincter, which is innervated by the pudendal nerve. Five patients showed bilateral and 2 patients showed unilateral absence of PNTML in the evacuatory disorder group postoperatively. Multivarite analysis revealed that low anastomosis (p < 0.001) was a significant risk factor for postoperative evacuatory disorder. The absence of bilateral or unilateral PNTML tended to be an affecting factor for evacuatory disorder (p = 0.06). CONCLUSIONS: Low level anastomosis was an independent risk factor for postoperative evacuatory disorder. The implication of absence of PNTML in evacuatory disorder awaits further study.     

Anal sphincter reconstruction in the elderly: Does advancing age affect outcome?

PURPOSE: This study was designed to determine whether advancing age affects outcome after anal sphincter reconstruction. METHOD: Anal sphincter reconstruction, performed on patients 55 years of age and older, was reviewed to determine if functional outcome was adversely affected by advancing age. A subgroup of patients was studied with anal manometry before and after repair and with pudendal nerve terminal motor latency (PNTML) before surgery. Results were compared with a younger group of patients. RESULTS: Between July 1986 and July 1991, 14 patients, ages ranging from 55 to 81, underwent anal sphincter reconstruction using an overlapping muscle repair. Ten patients were incontinent of solid stool and four of liquid stool. Improvement was seen in 13 of 14 patients: 7 (50 percent) complete control, 3 (21 percent) incontinent to flatus, and 4 (29 percent) incontinent to liquid stools (including the patient who failed to improve). Ten patients were studied with a continuous pull-out manometric technique and PNTML: one was not improved. There was minimum change in mean maximum resting pressure (35.0–37.9 mmHg). Mean maximum squeezing pressure increased from 66 to 75 mmHg overall. Patients with complete control had a mean maximum squeezing pressure of 81 mmHg compared with 60 mmHg in patients with residual incontinence. Mean anterior anal sphincter length increased from 2.92 cm to 331 cm. PNTML was normal (2.0±0.2) on one or both sides in all nine patients who improved (average, 2.1). The patient who failed to improve had abnormal nerve function bilaterally (2.4, 2.7). CONCLUSION: Anal sphincter reconstruction can be performed in elderly patients with improvements in the majority of patients. Total control can be achieved by restoring maximum squeezing pressure in a patient with normal pudendal nerve function.Poster presentation at the meeting of The American Society of Colon and Rectal Surgeons, San Francisco, California, June 7 to 12, 1992.     

Laterality effects of human pudendal nerve stimulation on corticoanal pathways: evidence for functional asymmetry

BACKGROUND: Although motor and sensory pathways to the human external anal sphincter are bilateral, a unilateral pudendal neuropathy may still disrupt anal continence. Anal continence can, however, be preserved despite unilateral pudendal damage, and so to explain those differing observations, we postulated that pudendal innervation might be asymmetric. AIMS: To explore the individual effects of right and left pudendal nerve stimulation on the corticofugal pathways to the human external anal sphincter and thus assess evidence for functional asymmetric pelvic innervation. METHODS: In eight healthy subjects, anal sphincter electromyographic responses, evoked to transcranial magnetic stimulation of the motor cortex, were recorded 5-500 msec after digital transrectal electrical conditioning stimuli applied to each pudendal nerve. RESULTS: Right or left pudendal nerve stimulation evoked anal responses of similar latencies but asymmetric amplitudes in six subjects: dominant responses (>50% contralateral side) from the right pudendal in four subjects and from the left in two. Cortical stimulation also evoked anal responses with amplitude 448 (121) microV and latency 20.9 (1.1) msec. When cortical stimulation was preceded by pudendal nerve stimulation, the cortical responses were facilitated at interstimulus intervals of 5-20 msec. Dominant pudendal nerve stimulation induced greater facilitation of the cortically evoked responses than the non-dominant nerve. CONCLUSIONS: Cortical pathways to the external anal sphincter are facilitated by pudendal nerve conditioning, in an asymmetric manner. This functional asymmetry may explain the presence and absence of anal incontinence after unilateral pudendal nerve injury.     

Reliability of pudendal nerve terminal motor latency

Aim: To evaluate reliability of Pudendal Nerve Terminal Motor Latency (PNTML). Methods: Forty healthy subjects, 24 women and 16 men, and eight female patients were included. Four patients had idiopathic faecal incontinence and 4 an anal sphincter rupture after childbirth. PNTML measurement was performed by two observers with the patient in left lateral and supine position. Examinations were repeated on another day to evaluate intraindividual reproducibility. Results: Interobserver reproducibility was 92% – 116% for PNTML. Degree of agreement for PNTML between left lateral and supine position was 86% – 111%. Intra-individual reproducibility in the supine and left lateral positions was 89% – 109% and 88% – 113% respectively. Normal values for mean PNTML were higher in women compared with men, 1.91 msec (2 SD, 0.52 msec) and 1.74 msec (2 SD, 0.33 msec) respectively, t = 2.44, 37 DF, P<0.01. Conclusions: Reliability of PNTML in terms of interobserver and intraindividual reproducibility was high. Women had higher normal values for PNTML than men.

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Résumé. Le but du travail est d'étudier la fiabilité de la mesure du temps de latence du nerf honteux (PNTML). Méthode: Quarante sujets sains, 24 femmes et 16 hommes, ainsi que 8 patients de sexe féminin ont été inclus dans cette étude. Quatre patients souffrent d'incontinence fécale idiopathique et 4 présentent une rupture sphinctérienne aprés accouchement. La mesure du PNTML a été réalisée par deux observateurs avec le patient en décubitus latéral gauche et en décubitus dorsal. Les examens ont été refaits à 24 heures d'intervalle afin d'évaleur la reproductibilité de l'examen chez un même patient. Résultat: La reproductibilité entre observateurs est de 92 à 116% pour la mesure du PNTML. La corrélation pour la mesure du PNTML en position de décubitus latéral gauche ou en décubitus dorsal est de 86 à 111%. La reproductibilité chez un même individu en position dorsale ou en décubitus latéral est de respectivement de 89 à 109% et 86 à 113%. Les valeurs normales pour un PNTML moyen sont légèrement supérieures chez la femme que chez l'homme: 1,91 msec (2 SD, 0,52 msec) et 1,74 msec (2 SD, 0,33 msec), t = 2,44, 37 DF, P<0.01). Conclusion: La confidence de la mesure du PNTML est élevée en termes de reproductibilité inter-observateur et intra-individuelle. Les valeurs normales sont plus élévées chez la femme que l'homme.

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Accepted: 19 June 1997     

Strength-Duration Testing of the External Anal Sphincter in Females with Anorectal Dysfunction

PURPOSE: The strength-duration test has been suggested as a means of assessing external anal sphincter function. This study was designed to investigate this claim by comparing the strength-duration test with established measures of external anal sphincter function. METHODS: Forty-nine females undergoing diagnostic anorectal testing (manometry, rectal sensation, electromyogram, pudendal nerve terminal motor latency, and endoanal ultrasound) also had the strength-duration test performed (which was repeated for each patient after a short rest period). RESULTS: The strength-duration test was repeatable. Statistically significant correlations were found between this test at pulse durations of 3 ms, 1 ms, and 0.3 ms with electromyographic activity of the external anal sphincter and with pressure in the anal canal during voluntary contraction. Significant correlations were found for durations of 100 ms, 30 ms, 10 ms, and 3 ms with the pudendal nerve terminal motor latency on the right and for the 3 ms and 0.3 ms durations with latency on the left. There were no correlations between the strength-duration test and resting pressure in the anal canal. CONCLUSION: The strength-duration test significantly correlates with the established measures of external anal sphincter function and its innervation. Therefore, this simple test appears to provide a simple measure of external anal sphincter denervation.     

Longitudinal study of the relationship between physical activity and knee pain and functional limitation in community-dwelling older adults

AimsTo describe the associations between interindividual (between-person) and intraindividual (within-person) variability in physical activity (PA) and knee pain and functional limitation among older adults. We also investigated the potential bidirectional association of between-person and within-person variability in knee pain and functional limitation with PA.MethodParticipants (N = 1064; 51% women; mean age 63 ± 7.4 years) were measured at baseline, 2.5, and 5 years. PA was measured using pedometers. Knee pain and functional limitation were assessed using the WOMAC scale. A two-part hurdle model, with adjustment for confounders, estimated the association of between-person and within-person variability in PA with knee pain/functional limitation (as the outcome). Linear mixed effect regression models described the association of between-person and within-person variability in knee pain and functional limitation with PA (as the outcome).ResultsBetween-person effects showed that participants with a higher 5-year average PA had lower average WOMAC scores (β= –1.17, 95% CI: –1.82, –0.51). Within-person effects showed that at time-points when participants had a higher PA level than average, they also had lower WOMAC scores (β= –0.85, 95% CI: –1.36, –0.35). Conversely, both between-person (β= –15.6, 95% CI: –22.5, –8.8) and within-person increase (β= –7.4, 95% CI: –13.5, –1.4) in WOMAC scores were associated with lower PA.ConclusionThese findings suggest that PA and knee pain/dysfunctional contribute to the development of one another. Pain can lead to changes in inter- and intraindividual PA levels, but the reverse is also possible – changes in PA results in changes in inter- and intraindividual pain/dysfunctional levels.     

Does perineal descent correlate with pudendal neuropathy?

A prospective study was undertaken to assess the potential correlation between increased perineal descent (IPD) and pudendal neuropathy (PN) in 213 consecutive patients. These 165 females and 48 males of a mean age of 62 (range, 18–87) years had constipation (n=115), idiopathic fecal incontinence (n=58), or chronic intractable rectal pain (n=40). All 213 patients underwent cinedefecography (CD) and bilateral pudendal nerve terminal motor latency (PNTML) assessment. Perineal descent (PD) of more than the upper limit of normal of 3.0 cm during evacuation was considered increased. Pudendal neuropathy was diagnosed when PNTML exceeded the upper limit of normal of 2.2 milliseconds. Although 65 patients (31 percent) had PD, only 16 (25 percent) of these 65 patients had neuropathy. Moreover, PN was also found in 42 (28 percent) of 148 patients without IPD. Conversely, only 16 (28 percent) of the 58 patients who had PN also had IPD, and IPD was present in 49 (32 percent) of 155 patients without PN. The frequency of PN according to the degree of IPD was: 30 to 4.0 cm, 6 of 27 patients (22 percent); 4.1 to 5.0 cm, 4 of 15 (27 percent); 5.1 to 6.0 cm, 4 of 12 (25 percent); 6.1 to 7.0 cm, 2 of 8 (25 percent); and >7.0 cm, 0 of 3 (0 percent). Linear regression analysis was undertaken to compare the relationships between measurements of PD at rest (R), push (P), and change (C=P–R) and values of PNTML. These values for all 213 patients were: R,r=0.048; P,r=0.031; and C,r=–0.050. The correlation coefficients were equally poor for all the individual subgroups analyzed, including the patient's sex or diagnosis. In summary, no correlation was found between PD and PNTML. The lack of a relationship was seen for the entire group as well as for those patients with either neuropathy or increased perineal descent. Therefore, the often espoused relationship between increased PD and PN was not supported by this prospective evaluation. Although increased PD and prolonged PNTML are frequently observed in patients with disordered defecation, they may represent independent findings.