Anal canal vector volume manometry

Abstract

Background: Anal manometry is routinely used in the assessment of the anal sphincters in patients with fecal incontinence or suspected sphincter injury. Such physiological information is complementary to the anatomical assessment provided by anal endosonography. The evolution of 3-dimensional anal endosonography provides more diagnostically useful information in complex cases. Vector volume manometry has been developed to give a 3-dimensional view of the anal sphincters.

Objective: We reviewed the published literature on this technique, with the intention of deriving a system of standardization based on the published literature and to summarize the derivation and physiological meaning of the parameters measurable by vector volume studies, as well.

Data sources: We undertook a MEDLINE search using the terms "vector volume" or "vector manometry" and "anal canal." We also reviewed further publications found from references cited in the original articles identified from the above search.

Study selection: Only English language articles of studies performed on humans were reviewed.

Intervention: Anal canal vector volume manometry was the intervention.

Results: With the development of automated puller systems and associated software, parameters such as total vector volume, maximum pressure, mean pressure, anal canal symmetry, anal canal length, and the length of the high-pressure zone can be readily calculated.

Limitations: There are conflicting studies related to the clinical value of both anal manometry and vector volume manometry, in part, because of the lack of standardization of equipment and technique.

Conclusions: The vector volume parameters have been shown to correlate with both imaging results and incontinence scores with automated puller systems. The clinical utility of vector volume manometry would be improved further by the standardization of equipment and technique. The main clinical utility may lie in the treatment selection and preoperative assessment of patients awaiting surgery for anal pathology that has yet to be evaluated.