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| 번호 | 제목 | 등록일 | 조회수 |
|---|---|---|---|
| 32 | Electromyography of the Pelvic Floor Musculature in the Assessment of Obstructed Defecation Symptoms [2001년 8월 DCR] | 2011-11-17 | 3496 |
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Claudio Fucini, M.D., Oscar Ronchi, M.D.,Claudio Elbetti, M.D.
From the Institute of Clinica Chirurgica I and tDepartment of Neurological Sciences, Faculty of Medicine,
University of Florence, Florence, Italy PURPOSE: The purpose of this study was to use electromyography to examine the behavior of the external sphincter, puborectalis muscle, and pubococcygeus muscle during attempted defecation in patients with symptoms of obstructed defecation and ha normal subjects to highlight differences of clinical significance.
METHODS: A total of 35 patients (31 females) aged 20 to 80 (mean, 53.7 -+ 13.3) years with unprepared bowel who had normal colon transit time and obstructed defecation symptoms and 12 voluntary control subjects (7 females) aged 23 to 68 (mean, 48 +11.5) years underwent an electromyography evaluation of
the activity of the external sphincter, puborectatis muscle, and pubococcygeus muscle during attempted defecation. The patients were also examined in separate sessions with defecography and anal manometry. RESULTS: During attempted defecation, puborectalis muscle and external sphincter always reacted in the same manner. When evaluated with pubococcygeus muscle, three main patterns of activity were observed either in patients or in controls: 1) coordinated activation pattern; 2) coordinated inhibition
pattern; and 3) uncoordinated or equivocal pattern: activation of pubococcygeus muscle with inhibition of puborectalis muscle/external sphincter, activation followed by" inhibition of the three muscles, and activation followed by inhibition of pubococcygeus muscle and no change in the others. We never observed activation of puborectalis muscle/external sphincter concomitant with inhibition of pubococcygeus muscle. The inhibitory coordinated pattern occurred significantly (P = 0.01) more frequently in controls than in patients. These subjects also presented a significantly (P = 0.01) lower frequency of pubococcygeus muscle inhibition. CONCLUSIONS: Either activation or inhibition appears as a physiological behavior, possibly adopted
in different circumstances, of the pelvic floor muscles during attempted defecation. The higher prevalence of coordinated inhibitory patterns in normal subjects and the lower frequency of pubococcygeus muscle inhibition in patients with symptoms of obstructed defecation, however, suggests that a loss of inhibition capacity progressing from pubococcygeus muscle to puborectalis muscle/external sphincter muscles could determine the insurgence of obstructed defecation symptoms in some subjects, who should therefore benefit from biofeedback retraining aimed at reacquisition of the inhibition capacity of all muscles of the pelvic floor during defecation. Pelvic floor musculature, normally in a state of continuous activity, relaxes during defecation. This assumption, other than by clinical examination, has been based primarily on the finding at electromyography (EMG) that both puborectalis muscle (PR) and external sphincter (ES) muscular activities are often simultaneously inhibited during straining.
This relaxation was subsequently associated in the laboratory with the widening of the anorectal angle at defecography and a decrease in anal pressure at manometry. The lack of inhibition or the increase in
PR muscle and ES activity observed at EMG in some subjects during defecatory straining has been and still is considered a major laboratory finding of what was termed puborectalis syndrome, nonrelaxing puborectalis syndrome, or anismus. This syndrome has been indicated as the cause of a functional outlet obstruction that determines an evacuation disorder characterized by straining at stools, digitally assisting evacuation, sensation of incomplete evacuation, and a need for enemas and is otherwise known as obstructed defecation (OD). However, the functional significance of PR/ES activation during defecation has been challenged periodically because a paradoxical activation of PR and ES has been observed in disorders other than OD, as well as in normal subjects. Conversely, some patients with OD symptoms have demonstrated normal inhibition of PR/ES muscular activity. Moreover, the correlation of PR/ES EMG with other laboratory investigations (defecography, manometry,
or balloon expulsion test) used in OD diagnosis has often been reported as poor. Nevertheless, the fact that biofeedback retraining aimed at relaxing and coordinating the pelvic floor musculature during defecation in patients with OD symptoms has obtained satisfactory results suggests that spasticity or lack of muscular coordination may have a relevant pathogenic role in some individuals. In the attempt to identify any eventual muscular disorder of the pelvic floor in these subjects, we reconsidered and re-evaluated the investigative role of EMG, which, despite some limitations, is the most direct and specific test for the examination of somatic musculature activity.
This re-evaluation was suggested on the basis of the following: 1) the results of a study that reported
that PR and another elevator (i.e., the pubococcygeus muscle (PC)) act differently in the same subject, thus challenging the concept of synchronous behavior of the pelvic floor during defecation, and 2) the longstanding approach that EMG, with either concentric or fine-wire needles, is performed on the PR and/or in the subcutaneous part of the ES because they are considered representative of the two muscular complexes of the pelvic floor (elevators and sphincters). The findings of our anatomic studies of the anorectal region, which evidenced the existence of individual variations in the development and overlapping arrangement of the PR muscle and the superficial part of the ES, highlight the risk of registering the activity of the ES alone in some subjects, using the usual method, while overlooking a possible different behavior of the elevators. In the present study, we elected to register the activity of the PC (a quite anatomically distinct part of
the elevators from the ES) during attempted defecation in normal subjects and in patients with OD. The overall aim was to elucidate the behavior of the elevators and sphincters in normal subjects, as well as to highlight possible modifications that might have clinical significance in patients with OD. Because some anatomic abnormalities such as rectocele and rectal intussusception have been reported
as having pathogenetic relationships with OD, the patients were also examined with defecography to rule out the presence of such abnormalities. Anal manometry was also performed to exclude the presence of Hirschprung's disease. |
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