Shafik A, Gamal el-Din M A, el-Sibaei O, Abdel Hamid Z, el-Said B
Department of Surgery, Faculty of Medicine, Cairo University, Egypt.
Eur Surg Res. 1992;24(3):188-96. doi: 10.1159/000129206.
The changes in the rectal neck (anal canal) pressure and electromyography (EMG) of the external anal sphincter and levator ani muscle were studied in 20 dogs before and after internal anal sphincter excision by 2 weeks and monthly up to 10 months. The rectal neck pressure dropped to 41% of the preoperative level. It was then gradually elevated from the beginning of the 1st month following excision till it reached 88% of the level before excision at the 10th month. The external sphincter EMG basal activity after internal sphincterectomy by 2 weeks showed a decrease in the amplitude of the slow and high potential waves. From the 1st to the 7th month after excision, changes in the frequency and amplitude of the waves occurred, and by the 10th month, the external sphincter showed the characteristics of the EMG of both the internal and external anal sphincters. The basal activity of the levator ani muscle increased at the 10th month. As reported previously, the changes in the rectal neck pressure and in the EMG of the external anal sphincter after internal sphincterectomy seem to be due to the histological changes in the muscle and include striated and smooth muscle fiber hypertrophy and proliferation. These changes adapt the external sphincter to serve the function of not only voluntary but also involuntary continence.
对20只犬在肛门内括约肌切除术前、术后2周、术后每月直至10个月，研究了直肠颈部（肛管）压力以及肛门外括约肌和肛提肌的肌电图（EMG）变化。直肠颈部压力降至术前水平的41%。然后从切除术后第1个月开始逐渐升高，到第10个月时达到切除术前水平的88%。肛门内括约肌切除术后2周，肛门外括约肌肌电图的基础活动显示慢波和高电位波的幅度降低。从切除术后第1个月到第7个月，波的频率和幅度发生变化，到第10个月时，肛门外括约肌呈现出肛门内、外括约肌肌电图的特征。肛提肌的基础活动在第10个月增加。如先前报道，肛门内括约肌切除术后直肠颈部压力和肛门外括约肌肌电图的变化似乎是由于肌肉的组织学改变，包括横纹肌和平滑肌纤维肥大及增生。这些变化使肛门外括约肌不仅适应自主控便功能，也适应非自主控便功能。
