Morphologic Analysis of Occipital Sinuses for Occipital Screw Fixation Using Digital Subtraction Angiography.
BACKGROUND
Numerous methods to achieve occipitocervical stabilization have been described, including the use of occipital plate/screw constructs. Bicortical screws may increase the pullout strength, but intracranial injuries to venous sinuses have been reported. This study was performed to analyze the variations in occipital sinuses to prevent sinus injury caused by the bicortical screw.


METHODS
Occipital sinuses of 1720 patients were examined using digital subtraction angiography. The data collected included patient age and sex, occipital sinus type, distance between occipital sinus and midline, depth from inion to occipital sinus, and distance between occipital sinus and midline occiput at different levels.


RESULTS
The mean age of patients was 57 years ± 13. There were 807 (46.9%) men and 913 (53.1%) women. The most common occipital sinus type was single occipital sinus off-midline (type B2). The least common occipital sinus type was absent occipital sinuses (type A; 8.7% of patients). There was no significant difference between age and occipital sinus type (P = 0.310). Also, the difference between sexes was not significant in regard to occipital sinus type in general. However, in subgroup analysis of type B1 and B2, there was a significant difference between sexes (P < 0.01). The mean depth from bone to occipital sinus was 19.913 mm ± 7.437.


CONCLUSIONS
The occipital sinus shows several variations, and many morphologic differences can be seen. Preoperative detailed examination by magnetic resonance venography or vertebral angiography may be required for cases in which bicortical occipital screw fixation is necessary to avoid occipital sinus-related complications.
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Dong Hoon
DH
Lee
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea. Electronic address: jatagi@daum.net.
Jae Taek
JT
Hong
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Jae Hoon
JH
Sung
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Ashish
A
Jain
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Joon
J
Huh
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Sang Uk
SU
Kim
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Joon Young
JY
Kim
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Jae Yoel
JY
Kwon
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Chul Bum
CB
Cho
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Il Sup
IS
Kim
Department of Neurosurgery, St. Vincent Hospital, The Catholic University of Korea, Suwon, Korea.
Sang Won
SW
Lee
D015901:Angiography, Digital Subtraction / Q000379:methods; D001863:Bone Screws / Q000009:adverse effects*; D003392:Cranial Sinuses / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000293:injuries; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009777:Occipital Bone; D011183:Postoperative Complications / Q000517:prevention & control; D019919:Prosthesis Implantation / Q000379:methods; D012189:Retrospective Studies; D012727:Sex Characteristics
Anatomy; Injury; Occipital fixation; Occipital sinus; Venous sinus