Felt-Bersma RJF, et al. - Given that 3D high-resolution anorectal manometry (3D-HRAM) potentially provides better guidance for surgical strategy in patients with perianal fistula by measuring regional pressures, researchers measured regional anal pressures with 3D-HRAM and compared these with 3D endoanal ultrasonography (3D-EUS) findings in patients with perianal fistulas. They noted profound local anal pressure drops in the fistula tract areas in patients normal mean resting pressures. Fistulotomy can cause local pressure drops.