Pre-contrast axial images demonstrate high density in the right sigmoid sinus
(A, black arrow), cortical veins (B, black arrows) and superior sagittal sinus (C, white arrow).
Cranio-cerebral MRI angiography were ordered, detecting the presence of thrombosis in the right sigmoid sinus
and the confluence between the transverse sinus and the superior sagittal sinus without intraparenchymal ischemic signs (Figures 1 and 2).
The reason for measuring between these anatomic structures was to determine the appropriate craniotomy site without violating important anatomic structures such as the sigmoid sinus
. Surgical simulation was conducted using a drill system (Bien Air, Le Noirmont, Switzerland), rigid endoscopes (Karl Storz, Tuttlingen, Germany; 2.7 mm in diameter, 14 cm in length, and 0[degrees] and 30[degrees] endoscopes), and cannula designed by us (endoscope cannula).
(b) Magnetic resonance angiography showing non-visualization of the transverse sinus, sigmoid sinus
, and the internal jugular vein (red arrow).
In a case series reported by Azin and Ashjazadeh (27) including 61 cases of CSVT, in 80.3% of the cases, the thrombosis was detected in the superior sagittal sinus; the sigmoid sinus
was affected in 6.5% and cavernous sinus thrombosis was detected in 4.9%.
Hypoplastic sigmoid sinus
was present in 51(25%) patients and aplastic sigmoid sinus
in 2(0.98%) patients.
Cranial magnetic resonance angiography showed narrowing of the transverse sinus and sigmoid sinus
. The complete blood count, chemistry panel, and serum levels of ferritin, C-reactive protein, and thyroid-stimulating hormone were all within normal limits.
MRI venography revealed diffuse attenuation of flow-related enhancement of the right transverse, right sigmoid sinus
, proximal part of left transverse sinus and right internal jugular vein suggestive of thrombosis (Figure 3).
All mastoid cells from the sinodural angle (Citelli's angle) were cleaned; the bone above sigmoid sinus
was thinned and did not show any infiltration of sinus.
According to previous studies, focal sigmoid plate dehiscence (SPD) due to focal bone defects in the region of the sigmoid sinus
is one of the very common etiologies of PT [3, 4, 11-14], which accounts for about 43%~60% populations in patients with PT [3, 14-16].
Intraoperatively, active venous oozing from the temporal base near the sigmoid sinus
Posteriorly the bone wall on the sigmoid sinus
was eroded by cholesteatoma.