Pelvic Floor Centre, Department of Colorectal Surgery, Oxford, UK.
Colorectal Dis. 2011 Sep;13(9):1014-8. doi: 10.1111/j.1463-1318.2010.02318.x. Epub 2010 May 17.
A subset of low-pressure fissures is not associated with typical internal anal sphincter hypertonia and may involve a different pathophysiological mechanism. We aimed to assess the manometric response of the internal anal sphincter to botulinum toxin in low-pressure fissures compared to high-pressure fissures.
Twenty five units of botulinum toxin (Botox(TM)) were injected directly into the internal anal sphincter. Maximum resting pressure (MRP) and maximum squeeze increment (MSI) were documented at baseline and four weeks after injection.
Nine (31%) of 29 patients had a low-pressure fissure. Those with an anterior fissure had a significantly lower median baseline MRP than those with a posterior fissure (66 vs 83 mmHg, P = 0.009). Significantly more patients with low-pressure fissures developed a contraction or no response (78%vs 30%, difference 48%, 95% CI 14-82%, P = 0.006). Those developing a contraction response had a lower mean baseline MRP than those developing a relaxation response (56 vs 86 mmHg, difference 30 mmHg, 95% CI 17-43%, P < 0.001).
Botulinum toxin appears to have an atypical contraction effect on the internal anal sphincter in low-pressure (usually anterior) fissures. This may be accounted for by blockade of acetylcholine released at parasympathetic nerve terminals and the sympathetic ganglion (relaxation). Low pressure fissures may be physiologically different from high-pressure fissures.
一部分低压力肛裂与典型的内括约肌张力过高无关，可能涉及不同的病理生理机制。我们旨在评估与高压肛裂相比，内括约肌在低压力肛裂中对肉毒毒素的压力反应。
将 25 个单位的肉毒毒素（Botox(TM)）直接注射到内括约肌中。在基线和注射后四周记录最大静息压力（MRP）和最大挤压增量（MSI）。
29 例患者中有 9 例（31%）存在低压力肛裂。前肛裂患者的基线中位 MRP 明显低于后肛裂患者（66 与 83mmHg，P=0.009）。有更多低压力肛裂患者出现收缩或无反应（78%与 30%，差异 48%，95%可信区间 14-82%，P=0.006）。出现收缩反应的患者基线中位 MRP 明显低于出现松弛反应的患者（56 与 86mmHg，差异 30mmHg，95%可信区间 17-43%，P<0.001）。
肉毒毒素对内括约肌在低压力（通常为前）肛裂中似乎有非典型的收缩作用。这可能是由于在副交感神经末梢和交感神经节释放的乙酰胆碱被阻断（松弛）。低压力肛裂可能与高压力肛裂在生理上不同。
