LAUSR

We are truly thankful for the correspondence sent by Zinicola and Cracco [1] and we want to emphasize the importance of Parks’ principles regarding supraelevator abscess (SLA) of intersphincteric origin [2]. Moreover, we think knowledge of these proctologic disorders is essential to perform correct drainage avoiding iatrogenic fistulae. There is still a need for prospective studies with a long follow-up. We found the theory of “skeletal muscle” rule very interesting and accurate and completely agree that when deciding on the drainage route is crucial to determine whether or not the infection has crossed the external anal sphincter. We would like to add that in the posterior anal area, if the infection propagates through the external anal sphincter a deep postanal space abscess could be created. This abscess has the particularity that is does not show external signs of sepsis, which delays the diagnosis and treatment. This therapeutic delay can produce a SLA of extrasphincteric origin [3]. Magnetic resonance imaging (MRI) is a useful tool for diagnosis of this condition. Furthermore, new studies are being made using 3D models made from MRI data for more complex cases [4, 5]. Declarations