Yash P. Sangwan

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. Marks) 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.

Can manometric parameters predict response to biofeedback therapy in fecal incontinence

PURPOSE Biofeedback therapy may improve fecal control in up to 50 percent to 92 percent of patients with fecal incontinence. Identification of favorable manometric parameters before biofeedback therapy may help in selection of patients suitable for such therapy. METHODS Twenty-eight patients with fecal incontinence (idiopathic, 11; iatrogenic trauma, 8; obstetric trauma, 9) who underwent biofeedback therapy were studied to determine whether manometric parameters could predict the result of therapy. Biofeedback was given using a computer software program designed to strengthen the external anal sphincter with auditory and visual feedback. RESULTS Thirteen patients (46.4 percent) achieved excellent results; eight patients (28.6 percent) had good results, but seven patients (24.5 percent) failed to improve after biofeedback therapy. Resting or squeeze anal canal pressure, pressure volume, sphincter length, sphincter fatigue rate, and cross-sectional asymmetry of the entire sphincter before biofeedback failed to reveal any statistically significant differences between responders and nonresponders. However, the cross-sectional asymmetry of the high-pressure zone within the sphincter at rest was greater in nonresponders than in responders (not improved, 25.8 percent; good result, 20.2 percent; excellent result, 15.4 percent; P < 0.07). This difference was even greater on squeeze (not improved, 21 percent; good result, 17.6 percent; excellent result, 13.2 percent; P < 0.04). The number of biofeedback sessions, response on bearing down, and quality of rectoanal excitatory reflex were not reliable indicators of outcome. No statistical difference was found in mean resting and squeeze pressures after biofeedback between responders and non-responders. CONCLUSIONS Except for increased cross-sectional asymmetry in the high-pressure zone, which may be a forerunner of adverse outcome, manometric parameters before biofeedback do not predict response to biofeedback therapy. Improvement in continence may be independent of resting and squeeze pressures achieved after biofeedback therapy.

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.

Spectrum of abnormal rectoanal reflex patterns in patients with fecal incontinence.

PURPOSE: Abnormalities of rectoanal inhibitory or excitatory reflex in patients with fecal incontinence are well described. A spectrum of abnormal responses, other than those already described in the literature, has been observed in some patients with fecal incontinence and forms the subject of this report. METHOD: Forty-three patients with idiopathic or traumatic fecal incontinence were studied to evaluate their reflex responses to balloon distention of the rectum, and results were compared with reflex responses of 29 control subjects with no anorectal complaints. RESULTS: Control subjects revealed normal reflex responses consisting of initial excitation followed by inhibition in the proximal anal canal and an excitatory response in the distal anal canal. Patients who were incontinent revealed five different types of reflex patterns. Eleven patients (25.5 percent) with segmental sphincter defects from obstetric injuries exhibited no distal excitation but had normal response in the proximal anal canal (Group 1). Eleven patients (25.5 percent) with idiopathic incontinence exhibited normal proximal response but an inhibitory as opposed to excitatory response in the distal anal canal (Group 2). Three patients (7 percent) with iatrogenic trauma failed to register an excitatory response in the proximal or distal anal canal but revealed a normal inhibitory reflex (Group 3). Nine patients (21 percent) with idiopathic incontinence revealed excitatory response in the entire anal canal but no inhibition (Group 4). Nine patients (21 percent) with idiopathic incontinence had a normal reflex pattern (Group 5). CONCLUSION: Excitatory and inhibitory components of rectoanal reflexes may selectively be abolished in neurogenic or traumatic insults to visceral and somatic anal sphincters, resulting in altered rectoanal reflex patterns.

Latency measurement of rectoanal reflexes

PURPOSE: Latency values of rectoanal reflexes may be altered in disorders of the pelvic floor. Evaluation of this relatively uninvestigated aspect of rectoanal reflexes may have diagnostic implications in patients with disorders of defecation. METHODS: We studied the latency of rectoanal inhibitory and excitatory reflexes to sequential balloon distention of the rectum with 60 ml and 120 ml of air in 14 normal controls (mean age, 41.5 (range, 19–66) years), in 14 patients with fecal incontinence (FI) (mean age, 44.2 (range, 28–72) years), and in 14 patients with slow transit constipation (STC) (mean age, 40.6 (range, 22–68) years). RESULTS: The mean latency of inhibition (FI=5.3 seconds; STC=4.6 seconds; controls=5.1 seconds) was remarkably similar for the three groups (P=0.19). The mean latency of excitation in the proximal anal canal (FI=2.8 seconds; STC =2.5 seconds; controls=2.8 seconds) was comparable in the three groups (P=0.58). The mean latency of excitation in the distal anal canal (FI=4.8 seconds; STC=2.6 seconds; controls=2.7 seconds) was prolonged in patients who were incontinent compared with the other two groups (P<0.01). CONCLUSIONS: Proximal rectoanal excitation and inhibitory reflexes, when present, have a constant latency, irrespective of the underlying condition. The different latency values for proximal and distal rectoanal excitatory reflexes in patients with FI may indicate disparate denervation damage to the external anal sphincter.

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.

Relationship between manometric anal waves and fecal incontinence

PURPOSE: The significance of manometric anal waves is uncertain, and their fate and diagnostic importance are unknown. It is conceivable that in neurogenic fecal incontinence (NFI) the frequency and amplitude of these waves may be altered into specific, recognizable patterns. Evaluation of this unexplored relationship between fecal incontinence and anal manometric waves has potential diagnostic use. METHODS: Anal motility was studied in 20 patients, each with NFI and traumatic fecal incontinence (TFI), and results were compared with findings in 20 control subjects to determine changes in frequency and amplitude of anal waves in fecal incontinence. RESULTS: Frequency of slow waves when present (NFI=9.5/minute; TFI=9.5/minute; control subjects=9.1/minute) was identical in the three groups (P>0.05). Amplitude of slow waves (NFI=mean, 4.3 mmHg; TFI=mean, 3.9 mmHg; control subjects =mean, 6.6 mmHg) was reduced in patients who were incontinent compared with control subjects but failed to reach statistical significance (P>0.05). Frequency of ultraslow waves when present (NFI=mean, 0.75/minute; TFI =mean, 0.6/minute; control subjects=mean, 1.2/minute) was not statistically different between the three groups (P>0.05). Amplitude of ultraslow waves (NFI=mean, 10.5 mmHg; TFI=mean, 23.4 mmHg; control subjects=mean, 29.6 mmHg) was significantly reduced in NFIvs.control subjects (P<0.01) and between TFIvs.control subjects (P<0.05). CONCLUSIONS: Manometric slow and ultraslow waves, when present, retain their frequency characteristics, irrespective of underlying disease. Amplitude of slow waves was not statistically different from control subjects, but the amplitude of ultraslow waves was significantly decreased in patients who were incontinent.