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| 번호 | 제목 | 등록일 | 조회수 |
|---|---|---|---|
| 44 | Botulinum Toxin Type-A in Therapy of Patients with Anismus [2001년 12월 DCR] | 2011-11-17 | 3803 |
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Y. Ron, M.D., Y. Avni, M.D., A. Lukovetski, M.D., J. Wardi, M.D.
From the Departments of Gastroenterology and Biostatistics, The E. Wolfson Medical Center, Holon and
Sackler School Medicine, Tel-Aviv University, Tel-Aviv, Israel INTRODUCTION: Anismus is a common cause of constipation and outlet obstruction. Standard therapy with laxatives or biofeedback has conflicting results. Surgical treatment gives poor results and has practically been abandoned.
PURPOSE: This study was designed to evaluate the efficacy of botulinum toxin type-A (Botox ®) injection to the puborectalis muscle in patients with anismus. METHODS: 25 patients (15 females; mean age, 23.2) with history of constipation and symptoms of outlet obstruction underwent anorectal perfusion manometry and video-proctography. All patients were found to have a nonrelaxing puborectalis muscle on both modalities. All have been unable to expel a rectal balloon. Each patient who participated in the study was randomly assigned to undergo local injection of Botox--10 units to each side of the puborectalis or 20 units to the posterior aspect of this muscle. Eight patients underwent further injections 1-5 every 3 months in accordance with previous results. Follow-up was conducted 1, 4, 12, and 24 weeks after injection. Straining, anorectal pain, and
overall satisfaction were assessed on a visual analog scale. Weekly evacuation, fecal incontinence, and complications were recorded. At the weekly meeting, each patient underwent anorectai manometry with a balloon expulsion test. RESULTS: Manometric relaxation was achieved after the first injection in 18 patients (75 percenO. Once relaxation was achieved, it lasted throughout the follow-up. Nine patients (37.5 percent) expelled the rectal balloon after the first injection. Seven of 16 patients who failed the first injection had an additional one. In 2 patients it was successful (28.6 percent). Symptom improvement of 29.2 percent in straining index was recorded during follow-up. In 3 patients (12.5 percent) pain developed after injection. No other complications were observed. Overall satisfaction with Botox injection results was observed in 58.3 %. CONCLUSIONS: Botox injection to the puborectalis muscle has been found to have a limited therapeutic effect on patients suffering from anismus. Our results justify the need for further double-blind placebo-controlled trials to determine the exact role of botullnum toxin type-A in anismus. Constipation is one of the commonest digestive complaints. The two major mechanisms are slow
transit and outlet obstruction. Constipation is generally described as infrequent defecation with two or fewer bowel movements weekly or straining at defecation at least 25 percent of the time. Most patients with slow transit constipation do not have an urge to defecate during the days or weeks preceding bowel movement. On the other hand patients, with obstructed defecation have regular and at times daily urges to defecate. Anismus, the principal cause for outlet obstruction, is defined as inappropriate contraction of the pelvic floor during attempts to evacuate. Most authors advocate the use of anorectal manometry or the use of either electromyography or video-proctography for the diagnosis of anismus. The pathophysiology of anismus is unknown. Signs of anismus have been noted in patients with anorectal pain and solitary rectal ulcer syndrome and even in patients with fecal incontinence. In patients with Parkinson's disease, this phenomenon has been regarded as focal dystonia of the pelvic floor. Therapy of anismus is quite disappointing. Trials using biofeedback training techniques have conflicting results and surgical options have been abandoned. Botulinum toxin type-A (BTX-A), a potent neurotoxin, has been in use since the 1970s. Its mode of action is inhibition of acetylcholine release in the presynaptic region. It has a cornerstone use in neurologic disorders characterized by excessive muscle contraction such as facial dystonias, vocal spasms, torticollis, and limb dystonias. In the past decade there have been reports of its use in achalasia, in anal fissure, and in anismus. DISCUSSION
Outlet obstruction is considered a common cause of constipation in western societies. In Israel, no epidemiologic data exists on the prevalence of anismus in the general population, but it is probably the commonest etiology of constipation in tertiary centers (our unpublished data). Unfortunately biofeedback
training brings relief to only 31 to 89 percent of treated patients. When measuring the "objective" parameters, manometric relaxation was attained by 75 percent of our patients, and this effect lasted throughout the entire study and follow-up. Balloon expulsion, which was our goal for "objective success" in assessing defecation dynamics, was achieved by 37.5 percent of patients after the first injection and by another 28.6 percent after the second (45.8 percent success after two injections). This discrepancy between manometric relaxation and balloon expulsion could reflect the coexistence of rectoanal motility disorder in addition to anismus or low sensitivity of this parameter in predicting success. Although common in use, reproducibility of the balloon expulsion test has been questioned by some authors. Taking into account the patient's view, 37.5 percent were satisfied with the overall results of BTX-A injection. Straining at defecation, which was the main complaint by our patients, decreased in 29.2 percent of them. Defecation frequency, which was within normal limits at the beginning of the study, did not change during follow-up as could be expected (only two patients had an increased defecation frequency).
Although some improvement in "objective" as well as "subjective" parameters were noticed, it cannot be
ignored that the major drawback of this study is the lack of a control population. The discrepancy between objective and subjective results could reflect the psychological profile of these patients, and because anismus is a functional disorder there is always a possibility for placebo effect. Another factor is the nonblinded fashion of follow-up, which could have biased patients' responses to therapy. Currently, only four studies concerning BTX-A injection to nonrelaxing puborectalis have been published. The series are small and uncontrolled, and it is hard to draw definitive conclusions as to the role of BTX-A in the treatment of the nonrelaxing puborectalis syndrome. The better results as presented by those authors could be a result of patient selection, the technique of injecting the substance (electromyographic (EMG) or ultrasound guided vs. palpation), or the dose of the BTX-A. In our study, which is the largest series published and the first to attempt orderly repeat injections, we observed only 37.5 percent (n = 24) success after the first injection and 28.6 percent (n = 7) after the second. We did not assess the psychological profile of our patients before entrance to the study. Depression could have a negative effect on results. All authors used an EMG-guided technique, which has been considered more accurate in guiding the exact location of the puborectalis muscle, although Hallan et al. states that this technique later proved unnecessary. A recent article by Maria et al. related to EMG as a "blind technique" and advocated the use of endoanal
ultrasound in guiding the injection to the exact location of the puborectalis muscle. In our study, endoanal ultrasound was not found to be of help in guiding injection. Because we estimate that nonrelaxing puborectalis is a major cause of constipation in Israel, our study was designed to be a simple clinical tool to solve this common problem. EMG/ultrasoundguided techniques are cumbersome and are neither readily available nor suitable for massive use in a large population of patients. Hallan et al. used the British form of BTX-A (Dysport ®, Porton, UK), which is more potent than that
used in the United States and Israel (Botox®; Allergan). The dose we used is larger than the one used in the American study. The inferior results reported in our study could be attributed to misplacement of the needle, although local dispersion of BTX-A has been reported. 28 Posterior injection of BTX-A did not offer better results than lateral injection. It has been suggested previously that the motor end plates are mainly concentrated in the lateral and posterior aspects of the puborectalis muscle. Complications of injections in this study were minor. Three patients complained of local pain at the
injection site. Fecal incontinence, local infection, or bleeding were not observed. However, complications of severe nonresponding constipation are substantial as expressed during follow-up of our patients. |
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