Abstract: Objective To explore the early diagnostic methods of traumatic intra-pterygoid sinus internal carotid artery pseudoaneurysm, to prevent misdiagnosis, and to choose the correct treatment to reduce the mortality rate. Methods We retrospectively analyzed the diagnosis and treatment history of 6 patients diagnosed as traumatic intracranial pterygoid sinus pseudoaneurysm, and combined the relevant literature at home and abroad to propose early diagnostic methods and select the best treatment plan. Results 6 patients had a history of head trauma, and had different degrees of recurrent nasal bleeding, 2 cases of monocular blindness; 1 of the 6 cases performed ligation of one side of the common carotid artery, 3 cases of occlusion of the aneurysm and the internal carotid artery with a detachable balloon, and 1 case of embolization of the internal carotid artery with a micro-spring coil, and the 5 cases were cured; 1 case died of hemorrhage after repeated nasal tamponade only. Conclusion: This disease can be fatal due to uncontrollable nasal bleeding, early diagnosis and reasonable treatment can cure it. Keywords: pterygoid sinus, internal carotid artery, pseudoaneurysm, traumatic pterygoid sinus, internal carotid artery, pseudoaneurysm, rare in clinic, all patients have different degrees of nasal bleeding, if clinically treated as a general nosebleed and misdiagnosed and mis-treated, the patient may be at any time difficult to control the hemorrhage and death. The authors and others treated 6 cases of traumatic internal carotid artery pseudoaneurysm in the pterygoid sinus from 1997 to May 2008, which are reported as follows. 1.1 General information 1.1 General information Among the 6 cases, there were 4 males and 2 females, aged 19-62 years old, with an average age of 33.8 years old, and the duration of the disease ranged from 7d to 60d, with an average of 26.5d. 1.2 Clinical information The 6 patients had a history of head trauma, of which 2 cases had monocular blindness. 3 cases of frontal lobe cerebral contusion were suggested by CT scan, 3 cases of intracranial pneumonitis; 4 cases of skull base fracture, and 2 cases of no obvious fracture were seen. 1 case developed nasal cavity fracture 7d after trauma, and 1 case of intracranial hemorrhage 7d after trauma. Nasal bleeding occurred in 7d after trauma, the amount was about 1000ml, and the bleeding stopped after nasal tamponade, and then similar nasal bleeding occurred 2 times after 1 week interval; 3 cases of nasal bleeding occurred in 18-24d after trauma, the amount was about 100ml to 800ml; 2 cases of bloody nasal mucus, followed by nasal bleeding, which increased gradually from 28d to 60d after trauma. Nasal endoscopy revealed that there was blood at the opening of one pterygoid sinus in one case, and there was blood at the opening of both pterygoid sinuses in one case, and there was bone destruction of the anterior wall of the pterygoid sinus. 3 of the 6 cases suffered from hemorrhagic shock several times, which was relieved by blood transfusion, fluid infusion, and repeated nasal tamponade, and in one case, because of the difficulty in controlling the bleeding, the unilateral common carotid artery was ligated at the same time as the blood transfusion. 1.3 Diagnosis: 3 cases were diagnosed as pseudoaneurysm of cavernous sinus segment of internal carotid artery by DSA selective cerebral angiography, 2 cases on the right side and 1 case on the left side, which was sac-like with a diameter of 0.6-1.5cm; CT scan showed the soft tissue mass shadow in the pterygoid sinus with a relatively uniform density, and CT enhancement showed the synchronous enhancement of the soft tissue mass shadow in the pterygoid sinus and the artery, of which 1 case had a transverse connection between the right and left pterygoid sinus, and the soft tissue mass shadow showed a swollen growth, and the pterygoid sinus was in a swollen growth, and the soft tissue mass shadow showed a swollen growth. In one case, the left and right pterygoid sinuses were connected, and the soft tissue mass showed expansive growth and bone resorption in the anterior wall of pterygoid sinus. In the other 3 cases, MRI showed a space-occupying lesion in the pterygoid sinus on one side, and MRA showed that the cavernous sinus segment of the internal carotid artery on the side of the pterygoid sinus lesion had a rounded shadow, which was connected with the internal carotid artery. 1.4 Treatment methods Surgical treatment 1 case in the local hospital has been confirmed as a pseudoaneurysm of the internal carotid artery in the right pterygoid sinus by DSA selective cerebral angiography, repeated bleeding after repeated right nasal tamponade, and was transferred to our hospital after the right carotid artery compression test (Matas test) for 7 d. On the second day of hospitalization, there was a sudden nasal hemorrhage, and the nasal tamponade was flushed out by the blood flow, and the right common carotid artery ligated, and the right internal carotid artery ligated, and the right common carotid artery ligated. Ligation of the right common carotid artery was performed immediately because the bleeding was difficult to control, and the bleeding stopped after the operation, and the patient was observed for 5d without obvious complications. Endovascular treatment In 3 cases, after DSA selective total cerebral angiography was performed to show the site of pseudoaneurysm, the internal carotid artery and aneurysm on the affected side were occluded with a detachable balloon, and the balloon was detached after observing for 30 min without any abnormal manifestations before detachment. After the balloon was released, the contralateral internal carotid artery and the ipsilateral vertebral artery were imaged to understand the collateral circulation, and all three cases showed good collateral circulation. 1 case was selected to use a micro-spring coil to embolize the internal carotid artery due to the intolerance of the patient in the internal carotid artery occlusion test. The other case failed to undergo the above treatment. 2. Results The possibility of pseudoaneurysm in the pterygoid sinus was considered in all 6 cases after more than 3 episodes of rhinorrhea, and in 1 case, the diagnosis was confirmed after 15 episodes of recurrent rhinorrhea of varying severity. 1 case was cured by ligation of the common carotid artery on one side of the carotid artery after the Matas test 7 days before treatment; 3 cases were cured by endovascular ligation of the internal carotid artery and the aneurysm after the Matas test 2-7 days; 1 case was cured by intravascular occlusion of the internal carotid artery with the use of a detachable balloon; and 1 case was treated by the occlusion test of the internal carotid artery. One case was cured by embolization of the internal carotid artery with a micro-spring coil. All of the above five patients were followed up for more than half a year without any recurrence, and one patient died due to repeated hemorrhage after repeated nasal tamponade for various reasons. 3.Discussion In 1996, Bouthillier et al. proposed to mark the whole internal carotid artery in the direction of blood flow with numbers (C1-C7), C1 neck segment, C2 rock segment, C3 rupture (hole) segment, C4 cavernous sinus segment, C5 bed segment, C6 eye segment, C7 traffic segment. At present, this segmentation method is mostly used in clinical practice. Traumatic internal carotid artery pseudoaneurysms in the pterygoid sinus mainly occur in the cavernous sinus segment (C4). Animal experimental studies have confirmed that the formation of traumatic carotid artery pseudoaneurysm is due to traumatic rupture of the whole layer of the arterial wall, the formation of a hematoma around the artery connected to the blood vessels, and the gradual dissolution of the blood clot in the lumen of the hematoma and its connection with the blood vessels under the impact of the tumor-carrying artery. At present, it is believed that there are two reasons for the formation of traumatic pseudoaneurysm of internal carotid artery: (1) the lateral wall of the pterygoid sinus covering the internal carotid artery is relatively thin, not more than 1mm, and the fracture fragments can directly damage the internal carotid artery which is immediately adjacent to the pterygoid sinus after the traumatic injury; (2) fracture of the pterygoid sinus can seriously injure the anterior medial wall of the cavernous sinus, which can make the internal carotid artery indirectly communicate with the pterygoid sinus through the cavernous sinus and form a pseudoaneurysm. The cavity of pseudoaneurysm is a layer of fibrous connective tissue formed gradually around the periphery of the hematoma cavity, without the structure of the arterial wall, this fragile structure, under the impact of the arterial blood flow, it is very easy to rupture and uncontrollable nosebleed occurs. Pseudoaneurysms of the internal carotid artery in the pterygoid sinus are often diagnosed due to recurrent rhinorrhea and are often misdiagnosed as general rhinorrhea treatment. In this group, 6 patients were diagnosed due to repeated bleeding, recurrent episodes, and gradually aggravated trend before considering relevant examinations. Some scholars believe that head trauma, skull base fracture and periodic nasal bleeding are the main basis for diagnosing traumatic internal carotid aneurysm. Some scholars believe that post-traumatic nosebleed, skull base fracture and monocular blindness are the three main signs of traumatic internal carotid artery pseudoaneurysm. In this group, only 2 cases of monocular blindness and 4 cases of skull base fracture were found in 6 cases, which did not fully support the above view. According to Zhi Xinggang et al [5], late onset, severe, recurrent, and finally fatal rhinorrhea are the characteristics of this disease, and Crowell et al suggested that recurrent rhinorrhea from traumatic internal carotid artery pseudoaneurysms in the pterygoid sinus can occur at any time after the trauma, but 88% of the rhinorrhea occurs about 21d after the trauma, and the mortality rate is as high as 50%. The authors concluded that a history of head trauma with late-onset, recurrent, and progressively worsening rhinorrhea should be considered as a possible cause of the disease, which should be highly suspected if bleeding or blood is found at the opening of the pterygoid sinus. After the suspicion of this disease, CT, CTA, MRI, MRA and other examinations should be carried out immediately, and DSA examination should be carried out as far as possible in order to confirm the diagnosis. At present, DSA total cerebral angiography is considered as the “gold standard” for the diagnosis of traumatic internal carotid artery pseudoaneurysm. If there is a high clinical suspicion of this disease, but the DSA cerebral angiography is negative, the patient still needs to repeat the cerebral angiography after 2 weeks to exclude the possibility of delayed pseudoaneurysm. Traumatic internal carotid artery pseudoaneurysm has a very small possibility of self-healing, and should be treated as early as possible once diagnosed. Treatment methods include: bilateral nasal tamponade, ligation of the common carotid and internal carotid arteries, muscular tamponade in the pterygoid sinus, injection of wire loops directly through the pterygoid sinus by puncture, and endovascular interventional therapy. The mortality rate of direct ligation of one side of the common carotid artery or one side of the internal carotid artery is reported to be 50%, which is generally not advocated to be used, unless in the absence of other effective treatment methods or first aid situations to consider the use of. Endovascular intervention is currently considered the preferred treatment. Before treatment, necessary training of neck pressure (i.e., Matas test) should be carried out to promote the establishment of collateral circulation, and according to the collateral circulation, the correct choice of treatment measures, such as detachable balloon, micro-spring coil, and overlay stent, can achieve better efficacy and reduce the postoperative complications and mortality.