Significance of the Change of the Anal Verge Position During Anal Surgery after Spinal Anesthesia

Lim, Seok Won; Kim, Do Hyoung

Abstract

PURPOSE
The anal verge is the border of the lowest part of the anal canal. However, grossly, it may be difficult to identify. Therefore, to assess the precise position of the anal verge, we performed this study.
METHODS
From August 1 to 31, 2006, 40 patients having anal surgery under spinal anesthesia were selected randomly. Prior to surgery, the anal verge was marked with the patient in the Sims's position. After marking, the anus was pulled bilaterally to both sides using bandages, and the lengths of the four areas were measured with the patient in the jackknife position.
RESULTS
With the patient in the jackknife position, the anal verge was moved laterally by an average of 1.09+/-0.36 cm. The shift distance of the anal verge relative to the anal area was measured; the shift distance in the posterior direction was 1.1+/-0.30 cm, that in the anterior direction was 0.85+/-0.25 cm, that in the right lateral direction was 1.22+/-0.41 cm, and that in the left lateral direction was 1.20+/-0.34 cm. The shifted distance to the posterior area was significantly longer than that to the anterior area (P<0.05).
CONCLUSION
When performing anal surgery with the patient in the jackknife position, the anal verge is shifted to the lateral side of the anus compared to its position when the patient is in the normal position. Notably, the shift distance to the posterior area was significantly longer than that to the anterior area. By assessing the precise position of the anal verge, the surgeon can reduce the resection range of the anoderm and create an appropriate drainage wound.