1. By Porf. Youssri Gaweesh
Professor of colorectal surgery
Alexandria university
Egypt

2. The cryptoglandular pathogenesis
This starts as an infection in the anal glands at the
base of the anal crypt. The abscess develops into the
plane between internal and external sphincters and
then extends to adjacent areas as the abscess expands

4. New anatomic concept
Kurihara et al described the posterior anal space with
the complex fistula in a totally different way.
The posterior deep space (PDS):
It lies in the posterior portion of the central anal
region surrounded by the musculature. It is bounded
by:
Anteriorly the internal sphincter
Supriorly inferior surface of the puborectalis
the inferior and lateral borders are the anterior surfaces
of the external sphincter.
So the PDS lies within the deep part of the external
sphincter in the intersphincteric space

5. The septum of the ischiorectal fossa
(SIF) :
It is a septum made of connective tissue found in the
ischiorectal fossa and it contains the inferior rectal
vessels and nerves.
It extends from the Alcock’s canal to the anal canal.
It splits the ischiorectal fossa into two compartments, an
upper one called the infralevator space (ILS), and the
lower one named clinical ischiorectal space (CIS).

6. The inferior rectal vessels and
nerves as they approach the anal
canal in the (SIF), they divide to
enter to the anal canal through
holes between the puborectalis and
the deep part of the external
sphincter, and through holes
between the deep and superficial
parts of the external sphincter.

7. These holes present potential
pathways for the extension of
the pus from the PDS on either
sides to either the ILS if
passing high , or to the CIS if
passing along the lower
branches.

8. Hanley et al. assumed that the pus
from the infected anal glands
penetrate the internal sphincter, the
longitudinal muscle layer and the
external sphincter to reach the deep
postanal space of Courtney from
which pus can spread to the
ischiorectal fossa.

10. this concept is dealing with a
primary lesion situated trans-
sphincteric while Kurihara et al.
consider that the primary lesion
is situated intersphincteric and
only its extensions laterally are
considered trans-sphincteric.

11. The posterior deep space (PDS) is
different from Courtney’s space.
The Courtney’s space is extrasphincteric
situated posterior to the superficial and
the deep parts of the external sphincter
whereas the PDS is situated within the
deep part of the external sphincter.

12. Levator ani
muscle
Puborectalis
(anorectal muscle
ring)
Deep
part
Superficial
part
Subcut.
part
Of
the
ext.
sph
.
Alcok’
s
canal
IL
S
CI
S
SIF
Infralevat
or
abscess
Ischiorec
tal
Supraleva
tor space
Coronal section showing Kurihara’s
new anatomical concept

13. Levator ani
(Ileococcygeus
)
Levator ani
(puborecta
lis)
1ry
lesion in
PDS
Deep part
Superficia
l part
Subcut.
part
External
sphincte
r
Midsagittal section showing Kurihara’s
new anatomical concept

14. Investigations
• MRI
• Findings show 80-90% concordance with operative
findings when observing a primary tract course and
secondary extensions.

17. Abdulsadek W.

22. Axial cut with extension
to the inferalevator
pocket

23. Coronal cut
demonstrating the
supralevator pocket that is
situated
intersphincterically

24. Saad M. Sh.

25. Unilateral approach

27. Another
case

28. Midline approach
for bilateral
extension

30. Unilateral approach