Shamblin type III carotid body tumor (CBT) is a rare chemoreceptor tumor that occurs in the carotid body. It is also known as carotid body paraganglioma (CBP) because it is a non-chromophilic paraganglioma arising from paraganglial tissue. In 1971, Shamblin1 classified carotid body aneurysms into three types, of which type III refers to carotid body aneurysms that are so large that they completely envelop the carotid artery, making it difficult to avoid vascular and cerebral nerve damage during surgery. Therefore, Shamblin type III CBT, as an epidemic and rare disease, has the characteristics of difficult surgical treatment, many intraoperative and postoperative complications, and high risk of occurrence.2,3 In this paper, we retrospectively summarize and analyze the treatment of 7 patients who were admitted and finally diagnosed with Shamblin type III CBT, and accumulate clinical experience for the future management of this type of surgery. 1, Data and methods 1.1 General data. 7 cases of Shamblin type III CBT, 1 male and 6 female, age 22-44 years old, average 30 years old, 5 cases on the left side and 2 cases on the right side, all unilateral, were diagnosed by treatment pathology from January 2006 to December 2011 in this treatment group. Six cases complained of painless mass under the cervical side of the mandibular angle, and one case complained of stabbing pain on the cervical side; the seven cases presented with symptoms for 3 months-5 years. Two of them showed incomplete paralysis of the affected posterior four cranial nerves before surgery, and both of them presented with poor feeding, choking and coughing, hoarseness, and episodes of dizziness and headache, and one of them had iron deficiency anemia. The family history was denied, and one case had a long history of living in a highland area. Local examination revealed a painless pulsating mass in the neck, and a systolic vascular murmur could be heard on auscultation. 1.2 Preoperative preparation: 1) diagnostic tests: ultrasound, digital subtraction angiography (DSA), CTA or MRA; 2) tumor scope: enhanced CT scan of the neck, magnetic resonance enhanced imaging (MRA); 3) temporary ballon oeclusion test (TBO): including balloon obstruction reflux pressure (including diastolic and systolic pressure) measurement, intraoperative test, and intraoperative test. If the blocking test is positive, daily neck compression test under ultrasound monitoring should be performed until the patient can tolerate a complete blocking of the carotid artery for more than 30 minutes. minutes or more. Carotid management options include preservation of the carotid artery, reconstruction after carotid resection, and carotid occlusion (preoperative balloon embolization or intraoperative ligation). In principle, the carotid artery should be preserved as much as possible; if the aneurysm is 1 cm away from the lower end of the internal carotid artery canal, reconstruction after resection can be considered if separation is difficult; if the aneurysm is close to or enters the internal carotid artery canal and jugular vein foramen, intraoperative reconstruction is very difficult. Preoperative embolization of both the internal carotid artery and the common carotid artery is feasible, which can greatly reduce the blood supply to the aneurysm. 4) Preoperative embolization of the vessel responsible for the aneurysm. If there is a well-known responsible vessel in the external carotid system and there is no large traffic branch with the intracranial and vertebral artery system, and there is a certain safe distance from the opening of the internal carotid artery, embolization can be performed within 48 hours before surgery with gelatin sponge; if communication between the responsible vessel and vertebral artery and internal carotid artery is found, embolization is usually not performed, or the trunk of the responsible vessel can be embolized with spring embolus to avoid If communication between the responsible vessel and vertebral artery and internal carotid artery is found, embolization is usually not performed, or the main trunk of the responsible vessel is embolized with spring embolization to avoid cranial infarction caused by fine emboli entering the communication vessel. 1.3 Surgical procedures. 2 cases of intracranial and extracranial communicating tumors of the jugular foramen were completely resected via lateral cervical combined suboccipital neurosurgery after preoperative balloon embolization of the internal carotid artery and common carotid artery; 3 cases of median mandibular cleft, 1 of which had been balloon embolized preoperatively, and the other 2 cases of saphenous vein reconstruction; 2 cases of lateral cervical pathway tumor resection, and the tumor was successfully detached from the carotid vessel wall. 4) After dissecting the internal carotid artery, ligate the ascending pharyngeal artery and occipital artery near the bifurcation, and to further reduce bleeding, temporarily block the external carotid artery and dissect the aneurysm on the surface of the artery or remove the aneurysm together with the external carotid artery. To further reduce bleeding, the external carotid artery can be temporarily blocked and the aneurysm can be dissected on the surface of the artery or removed together with the external carotid artery. Intraoperative care was taken to protect the above-mentioned nerves. 2. Results. The diagnosis was basically clarified by preoperative DSA and ultrasound. By enhanced CT and MRI, the neck masses ranged from 5.0 cm×3.5 cm to 10.7 cm×6.5 cm, and two cases were intracranial and extracranial communicating tumors through the jugular vein foramen, and their intracranial parts were 3.0 cm×2.5 cm and 3.0×2.0 cm, respectively. The results of preoperative interventional embolization showed that the blood supply of all tumors was mainly from the external jugular artery and the vertebral artery. In 6 cases, the ascending pharyngeal artery was the main responsible vessel, with the participation of the superior thyroid artery and occipital artery branches; in another case, the posterior occipital artery and the myenteric branch of the vertebral artery were involved in the main blood supply of the tumor. Among the 6 cases of ascending pharyngeal artery, 1 case had an obvious anastomotic branch with the vertebral artery, 2 cases had an opening adjacent to the internal carotid artery, and the remaining 3 cases were embolized with compressed gelatin sponge. No postoperative complications such as cerebral infarction occurred. The mean regurgitant pressure was 63/45 mmHG in all 7 patients who underwent balloon embolization, and in 2 cases the systolic regurgitant pressure was less than 50 mmHG. After 4 and 6 weeks of compression neck test, respectively, the common carotid artery was blocked by compression neck under ultrasonic monitoring for 30 minutes without symptoms. carotid artery reconstruction, and in 2 cases, complete dissection of the aneurysm was performed intraoperatively. Intraoperative bleeding and complications. In two cases of intracranial and extracranial communicating tumors in the jugular foramen, there were preoperative manifestations of posterior group IV cranial nerve palsy and Horner’s syndrome, and postoperative hoarseness and choking with water were aggravated, and the symptoms lasted for one year before returning to preoperative level and being able to work normally, with occasional choking with food and incomplete palsy after facial nerve displacement, which recovered 4-6 months after surgery. Of the remaining five patients, all developed vagus nerve palsy, one with permanent injury and the other four with recovery time of 3-7 months; two developed temporary hypoglossal nerve palsy and Horner’s syndrome, and one developed paraplegia, all of which recovered within 5 months after surgery. Postoperative follow-up. All patients were alive and well without intracranial complications at 6 months-5 years follow-up. 7 cases of Shamblin III CBT, 6 cases had complete resection of tumor at once, 1 case had a residual mass of about 1 cm in the jugular foramen, the mass increased to 3 cm at 3 years postoperatively, and the mass was stable without progression at 2 years follow-up after gamma knife treatment. 2 patients with intracranial and extracranial communicating tumors had complete recovery of the posterior four groups of cranial nerves only the paraneoplastic nerves. The food was semi-fluid and occasionally choking and coughing. 3. Discussion. Carotid body aneurysm accounts for 0.22% of head and neck tumors and is a relatively rare chemoreceptor tumor occurring in the carotid body, which is mostly benign and has a certain percentage of family history.4,5 Studies have shown that the occurrence of carotid body aneurysm is associated with chronic hypoxic stimulation. Type I and type II carotid body tumors can be surgically excised completely; type III tumors directly encase blood vessels and nerves, and surgery can easily injure neurovascular vessels, causing hemorrhage and nerve damage, and the quality of survival of patients after surgery is seriously affected.6 The indications for type III surgery are still controversial. For the majority of young patients with type III carotid body aneurysms, surgery is still an effective option. To reduce the risk of surgery, thorough preoperative preparation and reasonable intraoperative management are important to reduce complications. 3.1 Risks and value of preoperative interventional embolization The diagnostic value of DSA for carotid body aneurysms is irreplaceable, and also through selective angiography, the responsible vessels of the aneurysm can be observed and embolized or not according to the specific situation. All patients in this group underwent DSA, and most of the responsible vessels of the aneurysm were found to be from the pharyngeal ascending artery (6/7). The pharyngeal ascending artery is very close to the opening of the internal carotid artery, and there is a risk of dislodging the embolus into the internal carotid artery during intraoperative operation; at the same time, the pharyngeal ascending and vertebral arteries have traffic branches, and it is not advisable to use a small embolus intraoperatively to prevent it from entering the vertebral artery system and causing brain stem infarction. It is because of the anatomical characteristics of the pharyngeal ascending artery and the greater risk of embolization that preoperative embolization of internal carotid artery body aneurysms has been controversial.8 At present, although there is no evidence-based medical evidence from a large number of clinical cases that preoperative embolization can significantly reduce intraoperative bleeding, small samples of clinical summaries have shown that preoperative embolization can reduce intraoperative bleeding.9 In our group, we found that embolization of the internal and external carotid arteries (3 cases), superselective embolization (2 cases. ascending pharyngeal, superior thyroid and occipital arteries) and non-embolization (2 cases) were 250 ml, 940 ml and 1350 ml of bleeding, respectively. Although the number of cases was smaller in the three groups, the non-embolized group had smaller tumors and slightly more bleeding, and preoperative embolization significantly reduced bleeding. A recent study confirmed that Onyx percutaneous puncture achieved good clinical efficacy10 . 3.2 Surgical access and autologous blood transfusion. Type III carotid body aneurysms are large, and theoretically the mandibular fissure can fully expose the operative field and reduce intraoperative risk. However, after simultaneous embolization of the internal carotid artery and external carotid vessels, the number of bleeding will be significantly reduced, and the intraoperative operation becomes simple, and it is completely possible not to perform mandibular fracture. In this group of 2 patients with intracranial and external communication, both the internal and common carotid arteries were embolized preoperatively, and the mandible was not fractured by the combined suboccipital approach for resection intraoperatively. In the other 5 patients, 3 had mandibular fissures, which mainly facilitated intraoperative internal carotid artery reconstruction. Intraoperative autologous blood transfusion has been reported in the literature to reduce intraoperative allogeneic transfusion; this method was not used in this treatment group. The literature reports that 3-7% of carotid body aneurysms are malignant5,11 and their most important diagnosis relies on the presence of distant metastases.12 It is difficult to confirm the diagnosis by intraoperative freezing, so this treatment group believes that it is risky to use autologous blood transfusion if intraoperative malignancy cannot be excluded, and none of the patients in this group used autologous blood transfusion. 3.3 Internal carotid artery management. The degree of opening of the intracranial traffic branches of the internal carotid artery in Shamblin type III patients must be accurately assessed. Preoperative TBO is performed for carotid angiography, compensatory blood supply to the anterior and posterior traffic branches (willis loops), and regurgitation pressure determination. If the systolic regurgitant pressure is less than 50 mmHG, internal carotid artery pressure closure training must be performed until the patient tolerates it for more than 30 minutes during the Matas test before considering surgery. After satisfactory opening of the communicating branch of the internal carotid artery, the management of the internal carotid artery can be classified as preservation, reconstruction after resection or direct ligation. The experience of our treatment group is that careful preoperative review of the film combined with intraoperative observation determines which option to adopt. In principle, stripping is preferred, and reconstruction is considered if the risk is high or if the stripping ruptures intraoperatively; ligation is considered only if reconstruction is difficult. The present preoperative reading included unclear demarcation of the arterial epithelium and tumor envelope, and the Gordon-Taylor plane could not be dissected, and forced separation would lead to arterial vascular rupture and bleeding. Three cases in this group were embolized preoperatively, including two cases of intracranial and extracranial communication of the tumor. 3.4 Neurological complication prevention and postoperative functional rehabilitation. Type III carotid body aneurysms encase the nerves and are often accompanied by incomplete functional impairment of the nerves before surgery, and these symptoms will be aggravated after surgery, especially when the tumor crosses intracranially through the jugular foramen, the tumor and nerves in the jugular foramen area are tightly adhered, and it is difficult to preserve the nerves when removing the tumor.13; repeated separation, reconstruction and ligation of the internal carotid artery during surgery can cause stroke and trigger central nervous system symptoms.14 How to maximize the protection of Nerves are a problem that the operator must think about. The goal is to control the damage in a way that does not aggravate or cause new damage. The operator’s experience is that this type of surgery must be performed in a large enough field to fully expose the normal neurovascular surrounding the tumor, and then use bipolar coagulation to cut off the vessels communicating between the tumor and the outside world, and use the strategy of bipolar clamping followed by coagulation for the angered vessels on the nerve surface to achieve a delicate operation and avoid accidental injury to the cranial nerves. In conclusion, Shamblin type III carotid body aneurysm is rare clinically. In addition to the comprehensive consideration of ultrasonography, CT and MRI of the neck to clarify the diagnosis before surgery, DSA examination is essential. The temporary balloon block test is significant for the preoperative risk assessment of Shamblin III carotid body aneurysm; embolization of the carotid artery or the responsible vessel of the aneurysm is beneficial to reduce intraoperative bleeding; carotid body aneurysm with intracranial and extracranial communication requires multidisciplinary collaboration, and complete resection of the tumor in the jugular foramen is a difficult task, and functional exercise should be strengthened after surgery.