Novel applications of external anal sphincter muscle sarcomere length to enhance the anal canal function

M. R. Rajasekaran, Y. Jiang, V. Bhargava, R. L. Lieber, R. K. Mittal*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Background: Our recent studies show that the external anal sphincter muscle (EAS) operates at a sarcomere length range which is below optimal. In this study, we tested the hypothesis that by surgically increasing sarcomere length and bringing it close to the optimal length, EAS muscle function and anal canal pressure can be enhanced.Methods: Rabbits (n = 25) were anesthetized and subjected to either a sham or an EAS plication of different length by placing sutures at two locations, at a distance of 13%, 20%, 28%, or 35% of the circumferential length of the anal canal. Anal canal pressures were recorded before and after the plication. Anal canal was harvested and the EAS muscle sarcomere length was measured using laser diffraction.Key Results: Electrical stimulation of the EAS muscle resulted in a stimulus-dependent increase in the anal canal pressure (mmHg) and EAS muscle stress (mN mm-2). A significant increase in maximal pressure (212 ± 13 after compared with 139 ± 22 before plication) as well as stress (166 ± 10 after as compared with 88 ± 14 before plication) was recorded at 20% plication length. Passive anal canal stress at 20% plication was not significantly different compared with the sham group. The mean sarcomere lengths with sham and 20% plication were 2.11 and 2.60 μm, respectively.Conclusions & Inferences: EAS plication resulted in a length-dependent increase in EAS muscle sarcomere length with an optimal sarcomere length at 20% plication. These considerations may help guide repair of anal sphincter muscle defects in the humans.

Original languageEnglish (US)
Pages (from-to)70
Number of pages1
JournalNeurogastroenterology and Motility
Issue number1
StatePublished - Jan 2011


  • Anal continence
  • Anal sphincter injury
  • Length-tension
  • Plication

ASJC Scopus subject areas

  • Physiology
  • Endocrine and Autonomic Systems
  • Gastroenterology


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