High Resolution Anorectal Manometry (HRARM) in Healthy Egyptian Population

Transcription

1 Med. J. Cairo Univ., Vol. 79, No. 2, December: , High Resolution Anorectal Manometry (HRARM) in Healthy Egyptian Population HALA M.K. IMAM, M.D. and ESSAM ABDELMOHSEN, M.D. The Department of Internal Medicine, Faculty of Medicine, Assiut University Abstract Introduction: Individual motility laboratories should have their own published normal measurements based on their population, therefore, we needed to establish standard parameters for the first application of HRARM in evaluation of anorectal function. Aim of the Work: To evaluate the anorectal function by HRARM among a diverse of healthy Egyptian population in order to obtain normative data. Methods: The study was done at gastrointestinal motility lab, Internal Medicine Department, Assiut University Hospital, during the period of June 2008-June 2010, on 43 healthy volunteers 24 males and 19 females with average 44y (quartiles: 35-50y). We used a solid state probe with 8 transducers spaced 0.8cm with a rectal balloon mounted at the tip. The probe was introduced through the anal verge so the balloon is located at the rectum and the sensors at the rectum and the anal canal. External EMG electrodes were applied on either sides of anus. Subjects were asked to relax, squeeze the anal sphincter, bear down, and cough to measure anal pressures at these situations. Rectal sensation and recto-anal inhibitory reflex (RAIR) were evaluated by stepwise intermittent (10ml) balloon distention. Finally balloon expulsion test was done. Results: Anal resting and squeeze pressure were significantly lower, and anal canal was significantly shorter in women than men, while squeeze time, anal pressure increase with cough, push relaxation, RAIR, rectal sensation, and anal EMG were comparable in males and females. Age was negatively correlated with anal resting, anal squeeze pressure, and anal pressure increase to cough, while balloon expulsion time increased with age. Similarly, parity was negatively correlated with anal resting pressure. All subjects were able to expel the balloon. Conclusion: HRARM helps in understanding anorectal physiology. It is influenced by age, gender, and parity. This study can aid in diagnosing anorectal dysfunction in Egyptian population. Key Words: High resolution anorectal manometry (HRARM) Healthy Egyptian population. Correspondence to: Dr. Hala M.K. Imam, The Department of Internal Medicine, Faculty of Medicine, Assiut University Introduction ANORECTAL dysfunction is a common functional disorder affecting 10-20% of the population of all ages [1]. Anorectal manometry is essential not only in detection of defecatory disorders but also, it can affect its managements [2,3]. It is a simple, non-invasive technique that measures different aspects of contractile activity in anorectal region. It involves a couple of tests helping assessment of internal and external anal sphincters, anorectal coordination, and rectal sensation. It has been described previously to have high diagnostic potential [4]. Manometry verifies anal resting and squeeze pressures, and anal canal length. In the normal state, when the rectum is distended by fecal material, there is reflex relaxation of the internal sphincter the Recto-anal Inhibitory Reflex (RAIR) [5]. This can be elucidated in manometry by rectal balloon inflation and recording the consequence internal sphincter relaxation [6]. Other tests, as balloon expulsion test, anal electromyography, and saline continence test, can also be added to complement the evaluation [2,5]. Its main indications are fecal incontinence, constipation, anal pain, Hirschsprung disease, dyssynergic defecation and pre-and post-operative assessment of anorectal function and anatomic defects [7,8]. Normative data diverse with the population group. In addition, age, sex and parity can influence normal measurements. Therefore, it was recommended that individual motility laboratories to have their own published normal measurements based on their population [4]. High Resolution Manometry was first utilized to assess esophageal motility. Recently it has been 245

2 246 High Resolution Anorectal Manometry (HRARM) in Healthy Egyptian Population introduced as anorectal function testing. HRARM simultaneously assesses circumferential pressures in the rectum and throughout the anal canal, precluding the requirement to carry out a station pullthrough technique, which is quite cumbersome and time consuming [9]. However, its application in studying anorectal physiology is still under preliminary investigation. Its clinical utility is limited by the lack of published data from healthy individuals or defecatory disorder patients. We need to establish standard parameters for evaluation of anorectal function in heath and disease. Consequently, the aim of this study was to perform evaluation of anorectal function by HRARM among a diverse of healthy Egyptian population in order to obtain normative data. Subjects: Subjects and Methods During the period of June 2008-June 2010 we studied 43 healthy volunteers 24 males and 19 females with matched age group in gastrointestinal motility lab of Internal Medicine Department, Faculty of Medicine, Assiut University after a screening questionnaire determined that they had no anorectal symptoms or previous anorectal or colorectal surgery. Females were asked about their parity and their method of delivery. Subjects were excluded if they had a history of preexisting diabetes mellitus, neurological disorders, inflammatory bowel disease, irritable bowel syndrome, prior anorectal surgery. The study was approved by the medical ethical committee of Faculty of Medicine, Assiut University, and Informed consent was signed by the subjects. HRARM: HRARM was done using solid state 12Fr high resolution catheter with 8 pressure sensors spaced 0.8cm (Unisensor) with a rectal balloon was tied at its tip (Fig. 1). The system is plotting graphs with high resolution color topography and pressure waves tracing as well. Software for anal manometry was produced by Medical Measurement Systems (MMS), Enschede, Netherlands. Subjects were situated in the left lateral position with hips flexed to 90º. Evacuation enema was done to all subjects before the technique. The catheter was introduced through the anal verge so the balloon is located at the rectum and the sensors at the rectum and anal canal. Once positioned, the assemblies remained stationary for the duration of the study. External electromyography (EMG) electrodes were applied on either sides of anus. After allowing the pressures to stabilize, subjects were asked to relax, squeeze the anal sphincter, bear down, and cough to measure anal pressures at these situations. Resting anal pressure, representing the internal sphincter, was reported as the highest recorded average of the distal four pressure sensors. Squeeze anal pressure, reflecting the external sphincter, was reported by calculating the average maximal increase in pressure. The anal canal length was defined as the length (cm) over which a resting pressure was registered. Recto-Anal Inhibitory Reflex (RAIR) was tested by 50ml air balloon inflation. Rectal sensation was evaluated by stepwise intermittent (10ml) balloon distention. The subjects were instructed to account when they: First feel the rectal content (1 st sensation), the first sensation of urgency for defecation (first urge), a steady need to defecate (intense urge), and the maximum tolerable painful urge to defecate (max tolerable pressures), balloon volume at each sensation was recorded as the threshold volume. Finally balloon expulsion test was done by filling the balloon with 50ml of warm water and the subject was asked to sit on a commode and was left alone in the room for privacy after setting a stop watch. The subject was asked to expel the device, and to stop the clock. After 3min, if the subject was unable to expel the device, it was removed after emptying the water and considered failure of expulsion. Statistical analysis: The median and quartiles were used to express the distribution of normal parameters of HRARM. Male and female comparison was done by Mann- Whitney U test. We investigated the correlation between HRARM parameters with age, and number of parity in females by correlation coefficients, with values <0.5 were considered to be weakly correlated; while values >0.5 were considered to be strongly correlated. p-value of <_0.05 was considered statistically significant. SPSS version 16.0; Chicago, IL computer program was used in analysis. Results A total of 43 healthy subjects, 24 men; average 45yr (Quartiles yr) and 19 women; median age 44 yr (Quartiles yr) participated in this study. Among female subjects 2 were nulipara, 16 were multipara with both vaginal and Caesarian section with median number of parity 3; minimum 1 and maximum 7. All subjects well tolerated the test and its performance extended from 10-15min in most subjects.

3 Hala M.K. Imam & Essam Abdelmohsen 247 Anal Sphincter: Anal resting and squeeze pressure (Fig. 2) were significantly lower in women than men (Table 1). Moreover, anal canal was significantly shorter in women than men (p<0.05; Table 1). Whereas, sustained squeeze time, anal pressure increase with cough, and anal EMG during rest and squeeze were not significantly different between men and women (Table 1). The frequency distribution of anal canal length among all subjects is presented in (Table 2). On attempted defecation (bearing down), a normal response was seen in 32 subjects (75%), 18 men and 14 women and appeared as relaxation of the resting anal sphincter below the basal level and increase in rectal pressure (Fig. 3). Conversely, 11 subjects (25%; 6 men and 5 women) showed obstructed pattern of defecation (Fig. 4) appeared as failure of anal relaxation or paradoxical increase of anal pressure. However, when a 50cc balloon was inflated in the rectum and the subjects were asked to bear down on a commode, the condition persisted in only 2 men and 2 women. There was no statistical difference between genders in % of anal relaxation or increased rectal pressure on attempted defecation (Table 1). RAIR was first time elicited after inflation of the balloon 10cc of air in only 8% of volunteers, 20cc in 30%, 30cc in 42%, 40cc in 18%, and 50cc in 2%. Therefore, the majority of volunteers were elicited RAIR after inflation of the balloon with 30 to 40cc of air. When the balloon was inflated by 50cc of air abruptly the percentage of anal relaxation was 30% (20-47) in all subjects (Table 1) and (Fig. 5), and there was no statistical difference between genders. Rectal sensation: The threshold volumes for each degree of sensory perception starting from first sensation of rectal fullness, then first urge to defecate, intense urge, and maximal tolerable pressure were identified for all subjects. Table 3 represents the % of subject's elicited rectal sensations at different threshold volumes. There were no statistical differences between men and women as regard all rectal sensation (Table 1). All subjects were able to expel the balloon at median time 49; (quartiles 22-79sec) and (range 10sec- 3min). Women had longer expulsion time than men. Effect of age and parity: Age was negatively correlated with some anorectal parameters (Table 4 and Fig. 6), denoting that aging would lower both resting, squeeze anal pressure, and anal pressure with cough, but had no effect on squeeze time, % of anal relaxation, anal canal length, RAIR, and rectal sensation. On the other hand, aging prolonged balloon expulsion time significantly (Table 4). Similarly parity negatively correlated with anal resting ( r= 0.52, p<0.05) and squeeze pressure ( r= 0.56, p<0.05). Nulipara and women with only caesarian section (5 women) had higher resting anal sphincter pressure than multipara (14 women) [58 (55-63) vs 47 (40-57); p<0.05], however, squeeze anal pressure although was higher but not statistically different [117 (99-152) vs 109 (90-148) p>0.05]. RAIR and rectal sensation did not differ as well. Table (1): Gender comparison of the Anorectal manometric parameter (Mann-Whitney Test) median (quartiles) All patients n=43 Male n=24 Female n=19 p-value Age 44 (35-50) 45 ( ) 44 (35-49) Resting anal pressure 60 (48-69) 66 (59-71) 52 (42-60)* Squeeze anal pressure 131 (98-167) 142 ( ) 111 (92-149)* 0.02 Squeeze time 30 (29-42) 32 (29-42) 30 (30-42) Anal pressure to cough 79 (62-96) 79 (62-107) 80 (63-94) Attempted defecation: Rectal pressure 55 (48-60) 58 (47-67) 52 (43-60) % anal relaxation 37 (30-41) 37 (30-40) 32 (28-41) Anal canal length 4.2 ( ) 4.3 ( ) 3.8 (3-5)* 0.04 RAIR: % of anal relaxation 30 (20-47) 38 (20-47) 28 (18-46) 1 st sensation (cc) 25 (20-35) 30 (20-40) 25 (20-40) First urge (cc) 75 (60-100) 70 (60-95) 80 (65-100) Intense urge (cc) 140 ( ) 130 ( ) 140 ( ) Max tolerable volume (cc) 210 ( ) 230 ( ) 205 ( ) EMG at rest 6 (5-11) 5 (5-11) 6 (5-7) EMG at squeeze 44 (31-54) 53 (32-54) 36 (29-52) Balloon expulsion time (sec) 49 (22-79) 42 (30-62) 58 (38-81) <0.05

4 248 High Resolution Anorectal Manometry (HRARM) in Healthy Egyptian Population Table (2): Anal canal length percentages among all subjects. Anal canal length in cm % in all subjects <3 1 (2) (12) (28) (17) (9) (5) Table (3): Rectal sensation and threshold volume on sustained balloon inflation. Rectal sensation First rectal sensation First urge Intense urge Maximum tolerable pressure Balloon volume cc n (%) 4 (9) 8 (19) 14 (33) 5 (12) 1 (2) 1 (2) 7 (16) 16 (37) 7 (16) 3 (7) (5) (14) (42) (12) (5) (2) (12) (21) (26) (12) (7) Table (4): Correlation between age and HRARM parameters. r= p-value Fig. (1): Show solid state HRARM catheter with 8 pressure sensors spaced 0.8cm each one is circumferentially sensitive. Balloon tied at the tip to be placed in the rectum. Fig. (2): HRARM isobaric contour plot during rest and sustained squeeze showing resting anal pressure and sustained squeeze anal pressure, demonstrating appropriate increases in anal pressure according to color scheme at the left side of the Figure. The Right side of the Fig. shows the catheter position. Anal profile: Resting anal pressure Squeeze anal pressure Sq time Anal pressure with cough * 0.02* 0.05* % anal relaxation: To push Anal canal length RAIR Rectal sensation: 1 st sensation First urge Intense urge Max tolerable volume EMG at rest EMG with squeeze Balloon expulsion time * Fig. (3): HRARM isobaric contour plot during attempted defecation (push) demonstrating normal anal sphincter relaxation and increased rectal pressure during push.

5 Hala M.K. Imam & Essam Abdelmohsen 249 Discussion Fig. (4): HRARM isobaric contour plot during attempted defection (push) showing obstructed defecation pattern with paradoxical increase anal pressure instead of relaxation with increase rectal pressure. The clinical utility of the physiologic testing is limited because of lack of reference data from healthy individuals and lack of standardization [5]. Our study is considered the first report that investigated anorectal function by HRARM in healthy volunteers. It was conducted in an attempt to standardize measurement technique and normal values of the recently introduced HRARM for our motility lab in order to refine diagnosis and management of anorectal disorders for our population of patients, since consistency in reporting within a lab with reference to local control subjects is necessary regardless of the technique used [10]. The technique was easy to perform and to interpret and well tolerated by all subjects, and the probe design obviate the need for performing a pull-through technique. The pull-through technique is not favorable because anal sphincter is highly innervated by sensory neurons and is encircled by striated muscle that may be excited during manipulation producing falsely high pressure and making the test uncomfortable [5,11]. Fig. (5): HRARM isobaric contour plot during abrupt balloon inflation 50cc air demonstrating normal recto-anal inhibitory reflex (anal pressure relaxation). Anal pressure Age - anal_pressure_cough Age Resting_anal_pressure Age - squeeze_anal_pressure Fit line for total Fit line for total Fit line for total Age R Sq Linear = R Sq Linear = R Sq Linear = Fig. (6): Correlation between age and anal pressure during rest, squeeze, and cough. Previous data on the effects of gender and age on the pressure data and rectal sensation of anorectal manometry are variable and sparse. In this study the resting anal pressure and anal squeeze pressure were significantly lower in women than men (p<0.05). These findings were in consistent with previous reports [11,12]. Alternatively, another study [5] showed resting anal pressure did not differ significantly even though squeeze pressure and duration were significantly lower with shorter anal canal in women than men. Resting and squeeze anal pressure recorded in our study were lower than that described previously [13,14] using the pull-through technique that result in falsely higher resting and squeeze sphincter pressure, and the stationary technique but with conventional manometry [5,12]. Our findings concur with previous reports that showed that older subjects had lower anal sphincter pressures [15,16,17], as well as lower rectal sensation [18,17]. However, these results differ from others who reported that aging may not significantly affect anal motor function or rectal sensory function [14,5]. Gundling et al. [19] declared that age-related increase in sensory thresholds was only seen in females. The fact that age and female sex affect anal sphincter pressure would imply the predisposition to fecal incontinence in elderly females.

6 250 High Resolution Anorectal Manometry (HRARM) in Healthy Egyptian Population We have reported anal (EMG) during rest and squeeze with no significant difference between genders. This was obtained by surface electrodes and used to assess external anal sphincter activity and identify proper sphincter relaxation and contraction during rest and squeeze. In addition, it can identify patients with non relaxing pelvic floor in obstructed defecation [20]. As regards, the threshold for anal relaxation during rectal distension (RAIR) our data are in line with the other studies [5,12], in the majority of volunteers RAIR was elicited after inflation of the balloon with 30 to 40cc of air. It was preserved in all subjects with no gender or age difference. It is indicative of an intact myenteric plexus and is usually impaired in patients with Hirschsprung s disease [21]. Concerning the threshold for rectal sensation, our data support previous reports on the first sensation of distension [11,5,22,12] and desire to defecate [22,12], and the sensation of intense urge to defecate [12]. However, Rao et al. [5] had higher threshold for sensation of desire to defecate and intense urge and maximum tolerable volume. This could be attributed to differences in distension rates that were not specified. All subjects were able to expel the balloon with median time 49sec range from (10sec- 3min). Women had longer expulsion time than men. Normal subjects can usually expel a balloon, but patients who had constipation with megarectum and obstructed defecation are frequently unable to expel the balloon even if the rectal pressures are within the normal range [20]. However, there are several factors may lead to over diagnosis of functional outlet obstruction, including inability of the balloon to accurately mimic patient s stool, technical challenges to standardize the test, and patient embarrassment during the test [23]. The utility of the balloon expulsion test alone is limited, but in addition to other physiologic tests it may assist in the evaluation of patients with non-relaxing pelvic floor [24]. Obstructed pattern of defecation was observed in 25% of our healthy population. This percentage was comparable to that published by Rao et al among healthy subjects [5]. Although their number is small in the study, nulipara and caesarian sectioned women had higher resting anal pressure than multipara women, thus confirming previous reports [25,26]. This was explained by the anal sphincter defects resulted from vaginal delivery [27] that may lead to development of new fecal incontinence in 18% of women after first vaginal delivery [26]. On the contrary, previous study using conventional manometry reported no effect of parity on the resting pressure and squeeze pressure [28]. Conclusion: The study yielded normal HRARM parameters in Egyptian population. Some parameters vary with gender and age. It is difficult to compare these normal ranges in Egyptian with those in western population. HRARM findings in this study generated more understanding of anorectal physiology, since topographic analysis and isobaric plots format gave detailed information about anatomic segments of anorectal region and motor function, as well as rectal sensation. Therefore, allows greater understanding of anorectal function in clinical and research situation. It is easier, more rapidly to perform and interpret, and affords greater physiologic resolution by visual input than just numerical value of the conventional manometry. Establishment of normal values for this HRARM is crucial to help development of subsequent classification of anorectal and defecatory disorders. Therefore, its application in different anorectal disorder is warranted for future studies. References 1- WHITEHEAD W.E., WALD A., DIAMANT N., ENCK P., PEMBERTON J., WALD A. and RAO S.S.C.: Functional disorders of the anus and rectum. International Working Party Consensus. Rome Criteria II. Gut., 45 (Suppl. II): 55-9, RAO S.S.C. and PATEL R.S.: How useful are manometric tests of anorectal function in the management of defecation dis-orders? Am. J. Gastroenterol., 92: , SCOTT S. and GLADMAN M. MANOMETRIC: Sensorimotor, and neuro-physiologic evaluation of anorectal function. Gastroenterol. Clin. North Am., 37: , RAO S.S., AZPIROZ F., DIAMANT N., ENCK P., TOU- GAS G. and WALD A.: Minimum standards of anorectal manometry. Neurogastroenterol Motil. Oct., 14 (5): 553-9, RAO S.S., HATFIELD R., SOFFER E., RAO S., BEATY J. and CONKLIN J.L.: Manometric tests of anorectal function in healthy adults. Am. J. Gastroenterol. Mar., 94 (3): , BRIGHT T., KAPOOR R., VOYVODICH F., SCHLOITHE A. and WATTCHOW D.: The use of a balloon catheter to improve evaluation in anorectal manometry. Colorectal Dis. Jan., 7 (1): 4-7, BARNETT J.L., HASLER W.L. and CAMILLERI M.: American Gastroentero-logical Association medical position statement on anorectal testing techniques. American Gastroenterological Association. Gastroenterology, 116: , 1999.

7 Hala M.K. Imam & Essam Abdelmohsen WALD A.: Colonic and anorectal motility testing in clinical practice. Am. J. Gastroenterol., 89: , JONES M.P., POST J. and CROWELL M.D.: Highresolution manometry in the evaluation of anorectal disorders: A simultaneous comparison with water-perfused manometry. Am. J. Gastroenterol. Apr., 102 (4): 850-5, KEIGHLEY M.R., HENRY M.M., BARTOLO D.C. and MORTEEN N.J.: Anorectal physiology measurement: report of a working party. Br. J. Surg. Apr., 76 (4): 356-7, SUN W.M., DONNELLY T.C. and READ N.W.: Anorectal function in normal human subjects: Effect of gender. Int. J. Colorectal. Dis., 4: , CORSETTI M., PASSARETTI S., BARZAGHI F., LIM- IDO E., BOTTINI C., TESSERA G., GIANFRATE L., BONECCO S., NORIS R.A., CASTAGNA V., RADAEL- LI F., STROCCHI E., DINELLI M., FOSSATI D., STRA- DA E., VIVIANI G., CASA D.D. and MISSALE G.: Anorectal manometry with water-perfused catheter in healthy adults with no functional bowel disorders. Colorectal. Dis. Mar., 12 (3): 220-5, VARMA J.S., BINNIE N.R., KAWIMBE B., et al.: A regional audit of the investigation and treatment of colorectal and pelvic floor disorders ( ). Int. J. Colorectal. Dis., 8: 66-70, LOENING-BAUKE V. and ANURAS S.: Effects of age and sex on ano-rectal manometry. Am. J. Gastroenterol., 80: 50-3, McHUGH S.M. and DIAMANT N.E.: The effects of age, gender and parity on anal canal pressure: Contribution of impaired anal sphincter function to fecal incontinence. Dig. Dis. Sci., 32: , ALLEN M.L., ORR W.C. and ROBERSON M.G.: Anorectal functioning in fecal incontinence. Dig. Dis. Sci., 33: 36-40, FOX J.C., FLETCHER J.G., ZIMEISTER A.R., SEIDE B., RIEDERER S.J. and BHARUCHA A.E.: Effect of aging on anorectal and pelvic floor functions in females. Dis. Colon Rectum. Nov., 49 (11): , BANNISTER J.J., ABOUZEKRY L. avd READ N.W.: Effect of aging on anorectal function. Gut., 28: 353-7, GUNDLING F., SEIDL H., SCALERCIO N., SCHMIDT T., SCHEPP W. and PEHL C.: Influence of gender and age on anorectal function: Normal values from anorectal manometry in a large caucasian population. Digestion, 81 (4): , MELLGREN A.F.: Physiologic testing. In The ASCRS Textbook of Colon and Rectal Surgery: Second Edition, Beck D.E. et al. (eds.) Springer Science+Business Media, LLC., 2011: MEUNIER P., MARECHAL J. and MOLLARD P.: Accuracy of the mano-metric diagnosis of Hirschsprung s disease. J. Pediatr Surg., 13: 411-5, KRITASAMPAN P., LOHSIRIWAT S. and LEELAKU- SOLVONG S.: Manometric tests of anorectal function in healthy adult Thai subjects. J. Med. Assoc. Thai., 87: , VODERHOLZER W., NEUHAUS D., KLAUSER A., TZAVELLA K., MÜLLER-LISSNER S. and SCHINDL- BECK N.: Paradoxical sphincter contraction is rarely indicative of anismus. Gut., 41: , PEZIM M., PEMBERTON J., LEVIN K., LITCHY W. and PHILLIPS S.: Param-eters of anorectal and colonic motility in health and in severe constipation. Dis. Colon. Rectum., 36: , CALI R.L., BLATCHFORD G.J., PERRY R.E., PITSCH R.M., THORSON A.G. and CHRISTEEN M.A.: Normal variation in anorectal manometry. Dis. Colon. Rectum. Dec., 35 (12): , CHALIHA C., SULTAN A.H., BLAND J.M., MONGA A.K. and STANTON S.L.: Anal function: Effect of pregnancy and delivery. Am. J. Obstet. Gynecol., Aug., 185 (2): , SULTAN A.H., KAMM M.A., HUDSON C.N., et al.: Anal sphincter disruption during vaginal delivery. N. Engl. J. Med., 329: , RYHAMMER A.M., LAURBERG S. and HERMANN A.P.: Long-term effect of vaginal deliveries on anorectal function in normal perimenopausal women. Dis. Colon. Rectum. Aug., 39 (8): 852-9, 1996.