There is insufficient evidence to support a strong, moderate strength or weak recommendation for operative repair of venous sinus injuries for the purposes of improving survivability and sinus patency.

Sinus injuries should be repaired by open surgery when exsanguination or death from herniation would be more likely to occur in the absence of intervention to improve survivability.

No evidence or expert opinion supported distinct recommendations based on patient gender, age, wounding mechanism, or military vs. civilian context.

Venous sinus injuries fall within the spectrum of traumatic cerebrovascular injury suffered from foreign body penetration.1-13 Initial consequences of injury include rapid exsanguination, brain swelling and venous infarction if ligated, as well as a risk of air embolism. Delayed consequences include sinus thrombosis that can result in additional venous infarction events. Though surgical repair of these lesions can be extremely challenging, it is a neurosurgical truism that venous sinus injuries must be repaired to prevent the above consequences. The purpose of this key question was to determine whether or not there is evidence supporting benefits or harms of surgical or endovascular management strategies in the specific setting of pTBI.

The prior head injury guidelines did not address this specific topic directly.

Three studies met inclusion criteria for formal inclusion as evidence for this topic. There was one large retrospective nonrandomized study identified in a primarily military population by Kapp et al with penetrating traumatic brain injury (pTBI) and dural venous sinus injuries in the Vietnam War that assessed management of venous sinus injuries and reported mortality outcomes.6 The authors reported outcomes for two distinct groups, those with injuries from 1968 to 1970 (N=78), and those with injuries from 1971 to 1972 (N=16). Ninety-three cases were managed operatively at the 24^th Evacuation Hospital in Vietnam and one case was managed in Memphis, Tennessee. The authors report an operative repair protocol of: 1-Insertion of a large bore IV into a large vein to facilitate rapid blood transfusion; 2-A venous graft was harvested if deemed possible that a graft would be necessary for sinus repair; 3-Sinus bleeding was controlled by inflation of balloon catheters within the sinus; 4-An internal shunt was used to prevent venous sinus stasis rather than temporary sinus occlusion; 5-Non-essential sinuses were ligated if ligation was technically easier than repair; 6-Essential sinuses were repaired primarily if possible or with vein graft (reversed saphenous vein segments) if there was extensive injury. The authors reported no demographics for either study cohort. For the 1968 to 1970 cohort, there were 22 anterior superior sagittal sinus (SSS) injuries, 35 posterior SSS injuries, and 21 transverse sinus (TS) injuries. The mortality rates for anterior SSS, posterior SSS, and TS injuries were 5% (N=1/22), 43% (N=15/35), and 24% (N=5/21), respectively. The overall mortality for this cohort was 27% (N=21). For the 1971 to 1972 cohort the mortality rates were as follows: anterior SSS (0%, N=0/5), posterior SSS (0%, N=0/8), TS (33%, N=1/3). The overall mortality for this cohort was 6%. The anterior SSS was ligated in 27 cases from both cohorts. The mortality for this group was 4% (N=1/27). There were five patients who underwent primary sinus repair of the posterior SSS or transverse sinus and the mortality rate was 0%. There were six patients who underwent vein grafting for repair of the posterior SSS or TS and the mortality rate was 16.7% (N=1/6). The death in this group occurred in a patient with a TS injury. The authors advocate that if primary repair could be accomplished with less than 50% luminal narrowing, this should be done. Sinus repair by primary means remained patent without thrombosis in 100% of cases (N=5/5). Sinus repair by venous grafting remained patent in 83.3% of cases (N=5/6). There was one sinus thrombosis that occurred in a patient with a TS injury and venous grafting. The authors conclude that sinus repair can be accomplished with reduced blood loss and improved brain swelling by these means and that the greatest benefit of sinus reconstruction is in patients with injury involving the posterior SSS. However, there was no mention in this study of prevention or occurrence of venous infarction in patients with venous sinus injury.

Abdallah et al outlined surgical management of a traumatic SSS tangential injury that occurred in the Syrian Civil War.1 The authors report a case of a 33 year-old male injured by shrapnel with resultant midsagittal penetrating injury with deep-seated bone fragments within the right parietal lobe and interhemispheric subdural hematomas. Intraoperatively the authors noted an approximately 4 cm dural laceration at the junction of the middle and posterior third of the SSS. Immediate control of bleeding was obtained with manual pressure followed by insertion of two 16F Foley catheters with balloon inflation, both proximally and distally within the venous sinus. Once vascular control was obtained, the sinus was repaired with synthetic polytetrafluoroethylene vascular graft sutured in place with 6-0 polypropylene suture. Post-procedurally the patient was extubated and their Glasgow Coma Scale (GCS) score was 11. The authors initiated deep vein thrombosis prophylaxis 48 hours postoperatively for a total of 2 days and subsequently was prescribed a 3-month course of 100 mg oral aspirin daily. The patient ultimately improved and was discharged on postoperative day 5. At time of discharge his GCS had improved to 15 from 5 at admission. Long-term follow-up beyond 3 months was not available. The authors report no adverse events from repair of the sinus injury with vascular graft and the patient did not develop venous infarction.

An additional case report by Pricola et. al. outlined surgical management and venous sinus repair in a patient with a gunshot wound and retained fragment within the torcula.9 The authors report a case of a 21 year-old male with an occipital gunshot wound and an initial GCS of 10. Non-contrasted computed tomography (CT) of the head demonstrated midline occipital comminuted fracture with a retained bullet fragment within the torcula, along with small bilateral occipital epidural hematomas, and hyper density of the straight sinus and posterior aspect of the SSS concerning for thrombosis. CT venogram demonstrated thrombosis of the SSS, straight sinus, and poor opacification of the bilateral transverse and sigmoid sinuses suggestive of thrombosis. The patient was taken for emergent occipital and suboccipital decompression, which demonstrated a 1.5 cm laceration of the torcula. The authors removed all foreign and bony fragments and performed a combination primary repair (4-0 nylon) and patch graft (duramatrix, 4-0 surgilon suture) of the venous sinus defect. Continuous doppler monitoring was utilized and did detect venous air emboli throughout the repair. A Duragen onlay and cranioplasty were then performed. Postoperative CT angiogram demonstrated patency of the SSS, straight sinus, vein of Galen, Basal Veins of Rosenthal, and internal cerebral veins. A small nonocclusive thrombus was still present in the right TS. The patient was discharged home on postoperative day 3 with a complete neurologic recovery.

Several additional studies (not meeting inclusion criteria) were identified that reported outcomes for patients with dural venous sinus injuries although none directly addressed the key question and results were typically reported in aggregate for patients with concomitant arterial injuries.2-5,7,8,10-14 Additionally, the bulk of these cases were managed without direct surgical or endovascular intervention. There were no studies identified which reported incidence or outcomes relative to venous infarction and sinus injuries.

One study by Pylypenko et. al from Ukraine evaluated surgical management in 21 patients with dural venous sinus injury sustained in battle.14 Overall, 17 patients had direct repair of the sinus if one or two sinus walls were involved, and 4 patients required dural venous sinus ligation. There is mention in endovascular sinus thrombosis in an indeterminant number of patients. Outcomes were not consistently reported in this manuscript, however the majority of patients achieved a 12 month GOS of 4 or better.

One study by Hammon et. al reported active exsanguination from venous sinus injury as an indication for immediate neurosurgical intervention.5 The authors reported that if identified, major venous sinus injury bleeding was controlled by over-sewing a free muscle graft to maintain sinus patency and if transection had occurred, the sinus was ligated. The study cohort included 1,732 patients with pTBI during the Vietnam War who underwent operative intervention. The authors reported five deaths from venous sinus exsanguination and did not report incidence of venous infarction or granular results applicable to sinus repair.

One case series by Khan et al was identified which included three cases of surgically managed venous sinus injury.13 In one case a small SSS injury was directly repaired with suture (case 9). In a second case a SSS laceration was repaired with periosteal graft (case 11). In a third case a torn "lateral" sinus was ligated (case 17). Results of these cases were reported in aggregate with those of other cases and no conclusions can be drawn.

These studies provide insufficient evidence to determine the benefits and harms of surgical or endovascular management of venous sinus injuries to prevent venous infarction. They do, however, provide very low strength evidence that operative repair of venous sinus injuries is feasible and may improve survivability (assuming exsanguination would be more likely to occur in the absence of surgery) and sinus patency.

Amongst the many goals of surgical intervention in the setting of penetrating brain injury, hemorrhage ranks among the highest. As with all literature in this area, high quality, prospective randomized studies in the management of penetrating sinus injury are not possible. The literature experience outlined above provides a useful guide in this area.1-13 Control of hemorrhage from sinus injuries is of paramount importance should it exist. This can be accomplished by direct or augmented repair, interposition of a graft, sinus ligation, or a combination of these strategies. Sinus ligation, if in the anterior superior sagittal sinus or non-dominant transverse sinus, may be prudent and necessary. Care should be taken to preserve the middle and posterior thirds of the superior sagittal sinus when possible, with ligation as a last resort. Usage of multiple materials for repair (venous grafts, muscle, pericranium, dural inversion, synthetic materials) with sinus shunting are useful techniques in this area. While there is a successful case report of synthetic repair with a graft, long term follow up and ultimate outcome were not reported.1 The need for anti-coagulation/anti-platelet administration with this approach should be considered in the larger context of the global penetrating injury. It should be noted that, while there are numerous literature descriptions of the management of cerebral venous sinus thrombosis, a complication of traumatic sinus injury, by endovascular means, there are few reports of applications of these techniques in the setting of penetrating brain injury. One report out of the Ukraine references endovascular means to treat sinus thrombosis. Endovascular treatment has the potential to control blood loss if the expertise is available, if time permits (i.e. emergent cranial decompression can wait), or if achieved in a combined operating room with a multi-disciplinary team.

Many patients with penetrating cerebral venous injuries will die before they can be helped. Those who survive to hospital likely have characteristics that make them potentially salvageable. In some circumstances when there is not external hemorrhage these lesions can be managed non-operatively. In some circumstances endovascular treatment can be employed in conjunction with open surgery to help reduce blood loss. Open surgery for these lesions is extremely high risk and technically challenging. The entire operative team must be aware of and prepared for the risks of substantial blood loss and perioperative arrest. These can be desperate surgeries. Vascular neurosurgical expertise is very helpful when available. Good patient outcomes can be achieved in many of these patients, however, through a combination of luck and technical prowess.

In general, endovascular management of penetrating venous sinus injuries is not well described in the literature. There are no published case reports or described techniques (to the author's knowledge) advocating for endovascular intervention to preserve the venous sinus. It may be possible to help control active exsanguination with endovascular balloon assistance, but this would require combined endovascular operating rooms and acute multi-disciplinary management. Description of the rapid employment of this approach in practice would be beneficial. Current nitinol stent systems are, in general, designed for arterial deployment, are challenging to navigate in the cerebral venous sinus system, and require a period of dual antiplatelet therapy after deployment. Covered stent systems share the same characteristics with the added negative of covering and occluding draining cortical veins. Additional research and development of specific cerebral venous sinus stent systems that do not require dual antiplatelet therapy may provide some benefit in this and other areas. Here rigorously reported case reports and case series can make important contributions to the sparse literature.