Superior Sagittal Sinus Thrombectomy in Pediatric Head Injury

The dural venous sinuses are trabeculated channels lined by endothelium between the periosteal and meningeal layers of the dura mater. Cortical veins drain into the sagittal sinus, which in turn passes blood into the internal jugular veins via the transverse sigmoid sinus complexes [1]. In addition to draining deoxygenated blood from the brain, cerebral venous sinuses drain CSF via bulk transport through arachnoid granulations [2]. One rare but serious venous sinus pathology is cerebral venous sinus thrombosis (CVST).

CVST is estimated to have an incidence of approximately 2/100,000 per year in the general population and an incidence of approximately 0.67/100,000 per year in children [3, 4]. Known risk factors for CVST include oral contraceptives or hormonal supplementation, puerperium, cancer, recent surgery, traumatic head injury, history of clotting disorder, infection, and intravenous drug use [5, 6]. Acute sinus occlusion, especially when collateral circulation is insufficient, leads to derangement of Starling principles and a rapid increase in intracranial pressure (ICP), inducing immediate and profound venous-based ischemic effects with symptoms such as headache, nausea and vomiting, nonfocal neurologic deficits, and seizures. Without rapid correction, CVST can result in coma and death. Notably, the superior sagittal sinus (SSS) is the most common site of thrombus in adults and children, and it is a predictor of poor outcome, although recent studies have suggested that arachnoid granulations in the transverse sinus may be able to compensate adequately [7, 8].

CVST can be spontaneous or traumatic in nature. Spontaneous CVST is most commonly treated with anticoagulation in both adult and pediatric patients, although observation may be beneficial in less severe cases. The mainstay of treatment includes either low-molecular-weight heparin or unfractionated heparin, followed by an oral vitamin K antagonist or direct-acting oral anticoagulant for 3–12 months [9]. The management of traumatic CVST is more nuanced as the symptoms and severity of CVST may be masked by concomitant traumatic brain injury, and sizeable intracranial hemorrhage may necessitate surgical intervention and thus prohibit the use of anticoagulation. In these scenarios, mechanical thrombectomy represents a valid treatment option, particularly in the pediatric population due to the decreased circulating volume in children and the subsequent increased risk of further blood loss, which is compounded in the setting of acute trauma. In nontraumatic etiologies, small case series suggest that thrombectomy may be a safe and effective treatment of CVST in children [10, 11]. However, in traumatic settings, these clinical instances are rare, and the associated mechanical thrombectomy techniques and devices are relatively new and understudied.

The patient is a 2-year-old female with no significant past medical history who presented to the emergency department via emergency medical services as a level 1 trauma after a high-speed motor vehicle accident in which she was improperly restrained in a car seat. Emergency medical services reported concern for traumatic brain injury but that the patient was initially crying and moving all extremities, at which time her Glasgow Coma Scale (GCS) score was 9 (E4, V1, M4).

Upon arrival, the patient was hemodynamically stable. However, she began vomiting in the emergency department before becoming unresponsive to noxious stimuli (GCS 3). She was subsequently intubated for airway protection. Post-intubation physical examination was notable for briskly reactive pupils, 4 mm (mm) on the left and 3 mm on the right, bilateral upper extremity localization, and bilateral lower extremity withdrawal. Bedside extended focused assessment with sonography in trauma (E-FAST) was negative and computed tomography (CT) of the chest, abdomen, and pelvis was also negative. Laboratory analysis was grossly unremarkable. CT scan was notable for a C1 avulsion fracture, multiple skull fractures including a depressed left frontoparietal comminuted fracture that extended along and across the SSS, a left-sided high convexity epidural hematoma, traumatic subarachnoid hemorrhage overlying the left cerebral hemisphere, and trace subdural hematomas along the falx cerebri and left tentorial leaflet (shown in Fig. 1). CT venography was notable for a partially occlusive thrombus within the posterior SSS with extension into the torcula (shown in Fig. 2).

Due to the risk of blood thinners with her recent intracranial hemorrhage, as well as the concern for rapid decline given the severity of her clinical presentation, the decision was made to emergently take her to the angiography suite for mechanical thrombectomy rather than monitoring her on an anticoagulant infusion drip. Mechanical thrombectomy proceeded via a transfemoral venous approach and was ultimately completed approximately 2 h after her arrival and 3 h after her injury. Arterial and venous femoral access was obtained via femoral micro-puncture technique. A 4 French diagnostic arterial catheter and a 5 French venous sheath were placed. A 5 French Sofia catheter (MicroVention, Inc Tustin, CA, USA) was advanced into the SSS via a left jugular approach. Suction was applied to the aspiration catheter (Penumbra, Almeda, CA, USA) and immediately discontinued when brisk venous blood return was noted. Thrombotic material was found in the aspirate. Post-thrombectomy imaging demonstrated the presence of a remaining thrombus in the SSS, and the procedure was repeated a second time. Post-thrombectomy arterial and venous angiography demonstrated near complete removal of the venous sinus thrombus, with significantly improved cerebral venous outflow through the superior sagittal and dominant left transverse sinuses (shown in Fig. 3, 4). Throughout the thrombectomy, care was taken to minimize blood loss secondary to the procedure as it is typical to lose between 100 and 300 mL of blood in adult cases, given the suction applied to the large-bore aspiration catheters. Despite these precautions, likely owing to a combination of the patient’s low blood volume coupled with trauma, the patient did require one packed red blood cell transfusion intraoperatively due to hypotension and blood loss.

Postoperative scans revealed 90% clot removal with the successful restoration of blood flow and only a small non-flow-limiting residual thrombus within the sagittal sinus at the parieto-occipital junction (shown in Fig. 5). The patient was subsequently started on a heparin drip approximately 3 h postoperatively without noticeable increases in her intracranial bleeding and eventually transitioned to enoxaparin injections, which she continued for 5 months. The patient was extubated on postoperative day 1. On postoperative day 5, magnetic resonance imaging revealed no evidence of venous infarction, and CT venography revealed no residual intraluminal thrombus in the SSS (shown in Fig. 6). She continued to recover and was eventually discharged to a rehabilitation facility on postoperative day 13, at which time her neurological examination was notable for left-sided neglect and weakness (rated 3 out of 5 in the right upper and lower extremities). Follow-up visit at 9 months was notable for complete neurologic recovery.

Treatment of CVST in pediatric patients can be classified as acute versus chronic management. The acute phase may be further subdivided into supportive care and antithrombotic therapy. Supportive care measures include decreasing ICP (medically or surgically), rehydration, treatment of infection (if present), and seizure prophylaxis. The thrombus can be managed with anticoagulation or, as we demonstrate, mechanical thrombectomy. Surgical decompression may be necessary as a last resort when intracranial swelling becomes severe.

Unlike in adult patients with occlusive CVST where anticoagulation is somewhat routine regardless of whether there is concomitant traumatic injury, anticoagulant use in the setting of trauma in pediatric patients, especially in young children, is not routine [12]. Retrospective series have shown some degree of safety, but they also show that preexisting ICH is a risk factor for ICH progression. Prospective studies have not yet been performed. Likely owing to anticoagulation concerns in these situations, venous infarction remains a significant complication in pediatric patients and is associated with a 10% mortality rate with lasting neurologic deficits in approximately 40% of patients [13]. Additionally, due to the fragility of pediatric cerebrovasculature, hemorrhagic transformation is another serious complication of CVST. Current literature suggests that intracranial hemorrhage occurs in approximately 27–39% of adults with CVST and 61% of children [14‒16]. In contrast, venous infarction has also been reported in up to 22% of CVST cases [14]. Both hemorrhagic transformation and venous ischemia can bring about lasting neurologic sequelae including developmental delay, impaired speech development, motor deficits, epilepsy, and even coma and death [17]. As a result, great care must be taken to mitigate the effects of CVST and prevent hemorrhagic transformation and venous infarction.

The existing literature surrounding CVST largely focuses on spontaneous and nontraumatic cases rather than traumatic CVST. The safety and efficacy profiles of mechanical thrombectomy in the pediatric population are absent, with case reports and case series making up a majority of documented literature. Gadgil et al. [10] reported 7 patients, ages 7 to 16, who required endovascular intervention due to neurological deterioration despite systemic anticoagulation, six of whom had imaging evidence of venous infarction present at the time of the procedure. Six of the seven improved neurologically, as evidenced by modified Rankin Scale (mRS) scores of 0–1, while the last patient suffered from persistent, severe neurological dysfunction. Westwick et al. [11] documented a case in which a 15-year-old patient with SSS thrombosis received SSS thrombectomy and decompressive hemicraniectomy with excellent postoperative control of ICP, radiological recanalization, and good clinical outcome. Rammos et al. [18] reported the case of a 3-year-old boy with a progressively deteriorating level of consciousness and bilateral thalamic venous congestion who returned to his premorbid neurological status after mechanical thrombectomy of the left transverse sinus, sigmoid sinus, and internal jugular vein. Cellerini et al. [19] reported a case of a 5-year-old boy presenting with visual loss, progressive bilateral papilledema, and chronic otogenic thrombus of the right sigmoid sinus who obtained visual improvement and resolution of bilateral papilledema after mechanical thrombectomy and infusion of tPA.

Regarding traumatic CVST, anticoagulation remains a matter of debate with some studies suggesting it should be given to all pediatric patients and others arguing it should only be given to those with actively propagating thrombi. Propagation rates in untreated patients have been reported as high as 30%, whereas, in anticoagulated patients, hemorrhage has a reported rate of 6% [17]. These factors likely explain why more recent studies suggest that heparin products should be given to those without preexisting intracranial hemorrhage [13]. Matsushige et al. [20] reported on a group of 7 children, ages 1 month to 6 years, who presented with either acute epidural or subdural hematoma and evidence of CVST after traumatic injury. 3 patients (43%) were treated with supportive care, 3 (43%) with craniotomy, and 1 (14%) with anticoagulation. 2 patients (67%) treated with supportive care and 1 (33%) with craniotomy developed venous infarction; the lone patient treated with anticoagulation was found without neurologic sequelae at 1-year follow-up [20]. In a separate multicenter retrospective review of 29 patients, Roth et al. [20] observed that 18 pediatric trauma patients (62%) with CVST received anticoagulation and 10 of the 11 (34%) did not receive anticoagulation due to concomitant epidural hematoma. This group reported secondary cerebral bleeding in 2 patients (7%, 1 of whom received anticoagulation), persistent CVST after 1 month in 9 (31%), and continued neurologic symptoms at 2 months in 6 (21%) but did not find any correlation of any of these outcomes with anticoagulation status, although 1 patient (5.56%) experienced an adverse event after administration of anticoagulation (cephalohematoma requiring evacuation). Notably, they also remarked that the median duration of anticoagulant therapy was 58 days [21]. Xavier et al., [22] in a single-center retrospective review, identified 20 pediatric patients with traumatic injury and CVST. 14 (70%) received anticoagulation while the remaining 6 (30%) did not due to extensive intracranial hemorrhage, small and nonocclusive CVST, and lack of CVST propagation on subsequent imaging. Patients were started on anticoagulation anywhere between 1 and 48 days, although most received anticoagulation within 1 week. Complications arising from anticoagulation were seen in 3 patients (21%) and included recurrent epistaxis (n = 2) as well as minor, asymptomatic increases in subgaleal (n = 1) and epidural hematomas (n = 1), and anticoagulation was discontinued after fewer than 10 days in each. Complete cerebral sinus recanalization was seen in all 4 patients (100%) who did not receive anticoagulation and 8 patients (50%) who did receive anticoagulation. The average duration of anticoagulation was approximately 3.5 months with most patients receiving treatment for 3–6 months. Among patients treated with anticoagulation, 4 of 14 had full neurological recovery, 6 of 14 had minor sequelae (e.g., headaches, behavioral problems, and learning disabilities), and 4 of 14 had major neurological deficits (e.g., hearing impairment, diabetes insipidus, panhypopituitarism, hemianopsia, hemiparesis, depression, and significant learning disabilities). Among untreated patients, 4 of 6 had full neurological recovery, 1 of 6 had minor sequelae (e.g., mild residual headaches), and 1 of 6 had significant neurological deficits [22]. None of these studies, or any other studies to our knowledge, reported mechanical thrombectomy being used for treatment of traumatic CVST in pediatric patients. Our case of a young child receiving a successful mechanical thrombectomy for traumatic CVST is unique and adds to the existing literature by revealing that mechanical thrombectomy can be safe and effective for treating CVST in very young pediatric patients, even at 2 years of age.

Closed head injuries in pediatric patients may be associated with cerebral sinus injuries and subsequent CVST, with resulting venous drainage compromise and profound neurologic sequelae. Prompt diagnosis and management are required. When patients have no signs of existing intracranial hemorrhage, anticoagulation is preferable as a first-line therapy. However, if the patient continues to worsen or has a contraindication to anticoagulation, such as intracranial bleeding, endovascular mechanical thrombectomy may be an effective intervention when performed by an experienced interventionalist.

Ethical approval is not required for this study in accordance with local or national guidelines. Written informed consent was obtained from the parent/legal guardian of the patient for publication of the details of their medical case and any accompanying images.

The authors have no conflicts of interest to declare.

There were no funding sources for the manuscript under consideration.

Phillip Mitchell Johansen, Bronson Ciavarra, and Ryan McCormack: manuscript authoring and manuscript review. Matthew Kole and Gary Spiegel: manuscript review. Stephen Alan Fletcher: conceptual design and manuscript review.

Data are not available due to ethical reasons. Further inquiries can be directed to the corresponding author.