Effects of methylene-blue staining on the extent of pilonidal sinus excision.

Objective: We aimed to examine the effects of methylene-blue staining (MBS) on the volume of specimens after excision of pilonidal sinuses.

Method: This was a retrospective analysis of 135 excised specimens after pilonidal sinus (PS) surgery. All patients underwent procedures at the Department of Surgery of University Hospital Jena between 2000 and 2010. All specimens were measured in three dimensions. To calculate the volumes of excised specimens, we used a model of a hemi-ellipsoid. Demographic information (age, height, weight, body mass index, smoking status) were also obtained for all patients.

Results: Excised specimens with MBS had significantly larger volumes (p<0.001) as reflected in length (p=0.001), width (p=0.001), and depth (p=0.017) of the excised specimen compared with specimens that were not stained with methylene blue (MB). In addition, the volume was larger in subjects with a recurrent PS (p=0.021), which was predominantly the case in female subjects (p=0.025).

Conclusion: These data suggest that excised specimens with MBS had significantly larger volumes of the excised specimen compared with specimens that were not stained with MB. MBS of a fistula system could enable such a system to be marked sufficiently, thereby facilitating complete resection of a PS.