A brief review of dural venous sinus injury with a short case series

Injury to the dural venous sinus is a challenge to the neurosurgeon. The importance of venous sinus injury is the possibility of rapid and torrential hemorrhage, especially if it is from an open wound [1]. The essential task is to identify the injury early to prevent hypovolemic shock. Harvey Cushing’s observations during the first World war was that surgery might prevent the progressive venous thrombosis in wounds involving the major venous sinuses [2]. Cushing's review of 219 military head injuries had 14 cases of dural sinus injury with a mortality rate of 79% [3]. An analysis of cases with dural sinus injuries by Meier et al. showed a high mortality rate of 41% and intra-operative mortality rate of 20% [4]. The main causes of mortality are presence of severe head injury and profuse bleeding [1]. During surgery, there is chance of exsanguination. Early effective hemostasis is the main aim of surgery. Venous infarction and subsequent brain edema can delay neurological recovery.

The aim of the study is to analyze five cases of traumatic dural venous sinus injury, treated by the author. The study design is descriptive and retrospective analysis. The presentation, imaging findings, surgical management, method of hemostasis and outcome are studied. A literature search was done in Pubmed, EMBASE, Scopus and Google Scholar for articles describing traumatic dural venous sinus injury, imaging modalities and the methods of treatment. English was the language selected. Available articles and the articles in the reference list were analyzed, without any restriction of period. Reviews, case series, case reports, diagnostic studies and technical notes were assessed. The five cases of venous sinus injury are analyzed in the light of the review.

Review of the literature: The chance of hemorrhage is high in fractures or sutural diastasis over the dural venous sinuses [1, 3]. Depressed fracture over a sinus should be considered to have caused injury to the sinus. It can cause occlusion and thrombosis of the sinus also [5, 6]. The incidence of significant dural sinus injury was 1–5% of head injuries in earlier series [1, 3]. But it has come down to 1.7%, in the series of Kim et al. [1]. The anterior and middle third of superior sagittal sinus (SSS) is involved most frequently (60–80%), followed by transverse sinus and then posterior third of SSS [1‐6]. Torcular Herophili and sigmoid sinus also were involved in the series of 112 patients published by Meirowsky [2]. The anterior third of SSS can be ligated safely [1, 3]. The consequences of sinus injury are hemorrhage, intracranial hypertension, brain swelling and venous infarcts [5‐8].

Imaging: Multi-detector computed tomography(MDCT) scan and the recent advancement of three dimensional reconstruction(3 D CT) can show depressed fractures and sutural diastasis over sinuses very well [9, 10].Intracranial air bubbles adjacent to the fracture line, contusions, and hemorrhages can be seen in CT scans [9]. The ‘swirl’ sign, hypodensity within the hyperdense bleed, indicates active bleeding and chance of further expansion of haematoma [11, 12]. CT venography (multislice contrast-enhanced CT)can show occlusion of venous sinus [9, 13]. The ‘empty delta’ sign, in CT venography (CTV), represents a filling defect within a venous sinus [9]. Extrinsic compression of venous sinus secondary to a depressed skull fracture or extra-axial hematoma can be distinguished from venous sinus thrombosis by CT venography [13]. Magnetic resonance imaging can differentiate venous extradural haematoma [14]. MR venography (MRV) is a less invasive method to evaluate dural venous sinuses. Digital subtraction angiography (DSA) is the standard, but more invasive, investigation to know the patency of the venous sinus [6].

Indications for surgery: The depressed fractures over sinuses were managed conservatively, because of risk of massive hemorrhage during elevation [15]. But surgery is necessary in open fracture to clear the contamination and to repair the dura to reduce the chance of infection [1, 5, 16]. Conservative treatment can be tried if the dura is intact, and bone displacement is less and the wound can be cleaned [17]. Active bleeding from an open wound can produce rapid exsanguination and should be intervened rapidly [10]. An expanding hematoma in serial CT scans and the ‘swirl sign’ are indications for emergency surgery [11]. Other conditions necessitating surgery are occlusion of sinus and intracranial hypertension [5, 6, 8, 16‐20]. The venous thrombosis can lead to venous infarction, venous hypertension, and neurological deficits [16, 18]. Relieving the compression and repair of sinus injury will bring neurological improvement.

Surgery: The surgeon should be prepared to deal with bleeding from the sinus. Sufficient packed red blood cell (PRBC) units and fresh frozen plasma (FFP) should be arranged. Blood pressure should be monitored continuously and shock should be avoided. Surgery carries high morbidity and mortality. Craniotomy should be done with extra care to avoid further injury to the sinus. The evacuation of hematoma also should be gentle. Compression with gelatin sponge (Gelfoam) or temporalis muscle can reduce the bleeding [1, 3, 6, 21]. Other agents useful for topical hemostasis are oxidized cellulose (Surgicel), microfibrillar collagen and bioresorbable plate [22]. Topical hemostatic agents containing thrombin can be used. Tissue-glue-coated collagen sponge (TachoSil) and fibrin tissue adhesive (fibrin glue) also have been used successfully [23]. Hitching the dura to the adjacent periosteum and application of ligature or clip in the rostral part of sinus also may be needed to reduce the bleeding [1, 3, 4]. Suturing of the laceration with fine materials such as 6-0 Prolene can be done if proximal and distal control of sinus can be achieved [24]. Autologous venous graft also can be used for the repair [1, 3]. Decompressive craniectomy has to be done in case of intracranial hypertension due to venous edema or infarction [25].

The methods of hemostasis are summarized in Fig. 1.

Outcome: In the series of 112 cases of dural sinus injury, Meirowsky reported 13 deaths (11.6%) [2]. Meier et al. reported in a series of 39 cases that mortality ranged from 17% for injury to the anterior one-third of the superior sagittal sinus, to 100% for injury to the posterior part of the superior sagittal sinus [4]. The mortality for combined injuries of different sinuses was 67% and for transverse sinus injuries was 29%. In the report of surgical treatment of intracranial venous sinus injury for 111 cases by Huang SQ, the cure rate was 77.5% [26]. Elkatatny et al. reported mortality of 15%, and morbidity as moderate disability for 5%, in a series of 20 cases of traumatic dural venous sinus injuries [27]. The causes of morbidity are coagulopathy, intracerebral hemorrhage, and sinus occlusion [1, 3, 27].

Injury to the dural venous sinus and the resultant massive hemorrhage is a challenge to the neurosurgeon. Early diagnosis can be done if high index of suspicion is kept in cases of fractures over the sinuses. Serial CT scan, CT venography and MR venography can diagnose bleeding from the sinus and compression of sinus. The current literature shows that surgery is indicated in active bleeding, expanding hematoma, compression or occlusion of the sinus and intracranial hypertension. Now with the advancements in topical hemostatic agents (such as hemostatic matrix, bioresorbable plate, tissue-glue-coated collagen sponge, fibrin glue etc.), bleeding can be controlled more effectively. Repair with autologous venous graft or muscle has to be done in cases with uncontrollable bleeding. Occlusion of middle or posterior third of the superior sagittal results in venous infraction. Five cases were discussed. The patients with involvement of the middle third of SSS required decompressive craniectomy. All of them had good recovery.