Absence of the superior petrosal veins and sinus: Surgical considerations.
BACKGROUND
The superior petrosal vein, one of the most constant and largest drainage pathways in the posterior fossa, may result in complications if occluded. This study calls attention to a unique variant in which the superior petrosal veins and sinus were absent unilaterally, and the venous drainage was through the galenic and tentorial drainage groups.


METHODS
This study examines one venogram and another anatomic specimen in which the superior petrosal vein and sinus were absent.


RESULTS
The superior petrosal veins, described as 1-3 bridging veins, emptying into the superior petrosal sinus, are the major drainage pathways of the petrosal group of posterior fossa veins. In the cases presented, the superior petrosal vein and sinus were absent and venous drainage was through the galenic and tentorial groups, including the lateral mesencephalic or bridging vein on the tentorial cerebellar surface.


CONCLUSIONS
In cases in which the superior petrosal sinus and veins are absent, care should be directed to preserving the collateral drainage through the galenic and tentorial tributaries. Although surgical strategies for intraoperative management and preservation of venous structures are still controversial, knowledge of the possible anatomical variations is considered to be essential to improve surgical outcomes.
Department of Neurological Surgery, University of Florida, PO Box 100265, Gainesville, Florida, 32610, USA.
Ken
K
Matsushima
Department of Neurological Surgery, University of Florida, PO Box 100265, Gainesville, Florida, 32610, USA.
Eduardo Santamaria Carvalhal
ES
Ribas
Department of Radiology, Oita University, Faculty of Medicine, 1-1 Idaigaoka, Hasama, Yufu City, Oita, Japan 879-5503.
Hiro
H
Kiyosue
Department of Neurological Surgery, University of Florida, PO Box 100265, Gainesville, Florida, 32610, USA.
Noritaka
N
Komune
Department of Neurosurgery, Fukuoka University, Faculty of Medicine, 7-45-1 Nanakuma Jonan-ku, Fukuoka, Japan 814-0180.
Koichi
K
Miki
Department of Neurological Surgery, University of Florida, PO Box 100265, Gainesville, Florida, 32610, USA.
Albert L
AL
Rhoton
Microsurgical anatomy; posterior fossa; retrosigmoid approach; superior petrosal sinus; superior petrosal vein; venous complications