Revised morphology and hemodynamics of the anorectal vascular plexus: impact on the course of hemorrhoidal disease.
OBJECTIVE
The pathogenesis of hemorrhoidal disease is based mainly on the vascular hyperplasia theory. The aim of this study was to reassess the morphology and the functional mechanisms of the anorectal vascular plexus with regard to hemorrhoidal disease.


METHODS
The anorectal vascular plexus was investigated in 17 anorectal and five hemorrhoidectomy specimens by means of conventional histology and immunohistochemistry. Vascular corrosion casts from two fresh rectal specimens were used for scanning electron microscopy. Transperineal color Doppler ultrasound (CDUS) with spectral wave analysis (SWA) was performed in 38 patients with hemorrhoidal disease and 20 healthy volunteers.


RESULTS
The anorectal vascular plexus was characterized by a network of submucosal vessels exhibiting multiple thickened venous vessels separated by distinct sphincter-like constrictions. CDUS and SWA showed significant flow differences in peak velocities (6.8 +/- 1.3 cm/s vs. 10.7 +/- 1.5 cm/s; P = 0.026) and acceleration velocities (51 +/- 4 ms vs. 94 +/- 11 ms; P = 0.001) of afferent vessels between the control group and patients with hemorrhoidal disease.


CONCLUSIONS
Coordinated filling and drainage of the anorectal vascular plexus is regulated by intrinsic vascular sphincter mechanisms. Both morphological and functional failure of this vascular system may contribute to the development of hemorrhoidal disease.
Aigner
Felix
F
Department of Visceral, Transplant and Thoracic Surgery, Center of Operative Medicine, Innsbruck Medical University, Anichstrasse 35, 6020, Innsbruck, Austria. felix.aigner@i-med.ac.at
Gruber
Hannes
H
Conrad
Friedrich
F
Eder
Jasmin
J
Wedel
Thilo
T
Zelger
Bettina
B
Engelhardt
Victoria
V
Lametschwandtner
Alois
A
Wienert
Volker
V
Böhler
Ulrich
U
Margreiter
Raimund
R
Fritsch
Helga
H