Department of Medicine, Division of Gastroenterology, University of California, San Diego, and San Diego VA Healthcare System, San Diego, California 92161, USA.
Dis Colon Rectum. 2011 Nov;54(11):1373-80. doi: 10.1097/DCR.0b013e31822d0333.
We recently found that the anal canal function and external anal sphincter contraction can be enhanced by surgically adjusting the EAS muscle sarcomere length in rabbits. A 20% length plication of the external anal sphincter muscle results in significant increase in the anal canal pressure and EAS muscle stress without affecting its passive tension. The durability of the beneficial effect of external anal sphincter muscle plication on the anal canal function is not known.
We studied the long-term effects of optimal length external anal sphincter plication on the anal canal pressure, external anal sphincter sarcomere length, and anal canal histology.
Female rabbits (n = 16) were anesthetized and either sham (n = 4) or external anal sphincter plication (n = 12) surgery was performed.
The effect of external anal sphincter plication on the anal canal pressure was determined every 2 weeks for 6 months in 6 animals. Anal canal was harvested for sarcomere length and histological assessment.
External anal sphincter plication resulted in 50% to 60% increase in the anal canal pressure, and 80% to 90% increase in external anal sphincter muscle stress (during maximum electrical stimulus). The effect of plication was durable for the entire study period of 24 weeks. Sarcomere length increased from 2.11 ± 0.08 μm to 2.59 ± 0.03 μm immediately after plication and was 2.35 ± 0.08 μm at the end of 6 months. Histology revealed no significant differences in the muscle (30% vs 29%) or connective tissue components (70% vs 71%) of the anal canal between control and chronically plicated animals.
Normal external anal sphincter muscle plication results in long-term enhancement of the anal canal function without any untoward effects on the tissue architecture in the rabbit. External anal sphincter muscle plication could be an important strategy to improve the anal canal function in patients with anal incontinence.
我们最近发现，通过手术调整兔的外括约肌肌节长度，可以增强肛管功能和外括约肌收缩。外括约肌肌 20%长度折叠可显著增加肛管压力和外括约肌肌张力，而不影响其被动张力。外括约肌肌折叠对肛管功能有益效果的持久性尚不清楚。
我们研究了最佳长度外括约肌折叠对外肛管压力、外括约肌肌节长度和肛管组织学的长期影响。
对 16 只雌性兔子（n = 16）进行麻醉，行假手术（n = 4）或外括约肌折叠术（n = 12）。
6 只动物每 2 周检测一次外括约肌折叠对肛管压力的影响，持续 6 个月。取肛管检测肌节长度和组织学评估。
外括约肌折叠使肛管压力增加 50%至 60%，使外括约肌肌张力增加 80%至 90%（最大电刺激时）。这种折叠效果在 24 周的整个研究期间都是持久的。折叠后即刻肌节长度从 2.11 ± 0.08 μm 增加到 2.59 ± 0.03 μm，6 个月时为 2.35 ± 0.08 μm。组织学显示，对照组和慢性折叠组的肛管肌肉（30%比 29%）或结缔组织成分（70%比 71%）无显著差异。
正常的外括约肌折叠可长期增强肛管功能，而对外括约肌组织结构无不良影响。外括约肌折叠术可能是改善肛门失禁患者肛管功能的重要策略。
