10 Management of Venous Sinus Injuries
Introduction
Major dural venous sinuses form at the dural reflections where the superficial and deep layers of the dura split and the deep layer fuses to form the falx cerebri and the tentorium cerebelli. Injury to the dural venous sinuses may be encountered in penetrating and nonpenetrating head trauma or can result from planned or accidental disruption during a craniotomy. 1 – 3 The dural venous sinus has a three-sided lumen that is tethered laterally by the adjacent dura mater and deeply by the falx cerebri or tentorium cerebelli. Hemorrhage can arise from the sinus roof, lateral walls, venous lakes, arachnoid granulations, emissary veins, or cortical vein tributaries.
The decision to repair versus sacrifice the sinus is dependent on the location of injury. When repair is indicated, the type and extent of injury will largely dictate the optimal repair technique, which ranges from direct repair to segmental replacement.
Indications
Preprocedure Considerations
Radiographic Imaging
Computed tomography (CT)
Dural venous sinus injury should be suspected if imaging shows an epidural hematoma in the region of a major venous sinus. 5 In one study, 89% of epidural hematomas arising from a dural venous sinus had an associated fracture that crossed the sinus. 1 Posterior fossa epidural hematomas involve the dural venous sinuses in 42.5% of cases. 6
CT venography (CTV), which requires the administration of intravenous contrast and is taken during the venous phase, can be diagnostic of sinus thrombosis. The empty delta sign may be seen in the area of sinus thrombosis. 7 CTV is indicated when there is a depressed skull fracture over a dural venous sinus, which can cause sinus stenosis and thrombosis. 8 , 9
Cerebral angiography
Although angiography remains the gold standard for imaging the dural venous sinuses, it is invasive and time consuming, which renders it impractical in the setting of acute trauma.
Preoperative imaging (Fig. 10.1).
Medication
Antimicrobial prophylaxis is initiated.
Antiseizure prophylaxis is initiated.
Operative Field Preparation
General patient positioning
Secure the patient to the table, as up to 60 degrees of reverse Trendelenburg may be needed to minimize intracranial venous pressure if bleeding is profuse.
The injured dural venous sinus segment should be at the highest point of the operative field.
Avoid excessive neck rotation or flexion.
A bilateral craniotomy exposure is indicated to address injury to the superior sagittal sinus. A supra- and infratentorial approach is necessary to address injury to the transverse sinus.
Measures to maximize cranial venous outflow
Avoid compressive airway tape.
Minimize jugular compression from a rigid cervical collar.
Avoid excessive neck rotation or flexion.
Internal jugular central venous lines are contraindicated due to the possibility of iatrogenic thrombosis and impairment of cranial venous outflow.
Blood loss
Large volume hemorrhage may occur from the injured venous sinus. Significant losses may also occur—both preoperatively and intraoperatively—from scalp, bone, and brain.
Packed red blood cells, platelets, and fresh frozen plasma must be available in the operating room.
Venous air embolism
Venous air embolism may occur when the head is elevated above the heart, resulting in negative pressure in the dural venous sinus—allowing air to enter and become trapped in the right atrium.
A fall in the end tidal pCO2 and hypotension may ensue. Strong consideration should be given to the use of capnography, a precordial Doppler probe, and an arterial line. Air embolism produces “washing machine” sounds by Doppler.
Removal of air from the right atrium is possible if a right atrial catheter—placed via the brachial or subclavian route—is in place.
Segmental sinus replacement
If substantial sinus disruption is anticipated, vascular reconstruction equipment should be available, including a properly sized temporary vascular shunt, Fogarty balloon catheters, nonabsorbable vascular suture, and a vein allograft.
Operative Management
Treatment is discussed separately for the following parts of the venous sinus system: anterior one-third of the superior sagittal sinus, posterior two-thirds of the superior sagittal sinus, torcular herophili, and dominant transverse sinus.
General Considerations by Anatomic Location
Superior sagittal sinus—anterior one-third
The majority of injuries in this area can be managed with tamponade techniques or direct suture repair if the laceration is small.
Lacerations that are too large to suture directly often can be treated with a sutured, bolstered patch.
Lesions that cannot be repaired can be treated relatively safely with sinus ligation via an encircling suture or vascular clips.
Superior sagittal sinus—posterior two-thirds
This portion of the sinus should be repaired or replaced in virtually all cases, but especially when major cortical venous drainage is involved.
Avoid primary suture closure that compromises greater than 50% of the sinus lumen, as this may be more likely to result in compromised flow and eventual sinus occlusion.
If stenosis is likely to result from primary suture repair, a patch should be placed.
Replacement of segments of the superior sagittal sinus is the most extreme of interventions, reserved only for those cases involving either the majority of the dorsal wall or both lateral walls, in which a sutured patch cannot reconstruct a lumen at least 50% of the original size.
Kapp et al developed an internal shunt for use during sinus reconstruction. 3 , 4 This was made of a pediatric endotracheal tube with a pediatric tracheostomy cuff placed at each end. Sindou and Alvernia avoided the balloon shunt and Fogarty balloon catheter due to risk of injury to the sinus endothelium, advocating, instead, for direct packing of the lumen with hemostatic material. 2 Both emphasize the need for sinus thrombectomy of the proximal and distal ends of the sinus repair to ensure patency.
Torcular herophili
Injuries that substantially disrupt the torcular herophili are rarely survivable and, in most cases, the clinical grade of the patient is such that expectant management—without surgical intervention—may be appropriate.
The techniques for tamponade, primary repair, and patching described for injuries to the superior sagittal sinus also apply to the torcular herophili. 1
Dominant transverse sinus
The techniques for tamponade, primary repair, and patching described for injuries to the superior sagittal sinus also apply to the superior sagittal sinus.
Sindou et al described a bypass of the transverse sinus to the external jugular vein using a saphenous vein graft in a patient with bilateral transverse sinus thrombosis. 10 Meticulous wound closure is necessary to prevent compression and subsequent thrombosis of the subcutaneous vein graft.
Operative Procedure
Surgical Approach to Injuries of the Anterior Third of the Superior Sagittal Sinus
Positioning (Fig. 10.2)
Related posts:
1 Surgery for Epidural and Subdural Hematomas
6 Elevation of Depressed Skull Fractures
7 Invasive Neuromonitoring Techniques
5 Surgery for Cerebellar Stroke and Suboccipital Trauma
4 Decompressive Craniectomy for Intracranial Hypertension and Stroke, Including Bone Flap Storage in Abdominal Fat Layer
3 Surgery for Cerebral Contusions of the Frontal and Temporal Lobes, Including Lobar Resections
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