94 Clinical and Experimental Otorhinolaryngology Vol. 3, No. 2: 91-95, June 2010 medialization laryngoplasty. Pathologic examination of all tumors revealed benign histol- ogy of paragangliomas without cases of malignant CBT. There was no recurrence or delayed complications at the median fol- low up of 29 months. DISCUSSION Although most CBTs are benign and slow growing, surgical exci- sion is the treatment of choice. Some authors have found that radiotherapy is effective in inhibiting further growth of CBTs. However, it is often considered to be an alternative treatment modality for patients who cannot undergo surgery due to exten- sive involvement, multiple tumors, and high operative risk (10). During operation, all neurovascular structures should be iden- tified to reduce complications. Proximal and distal control of the carotid arteries with early ligation of feeding arteries is important to achieve complete tumor resection. Elective ECA ligation can be helpful for tumor mobilization, but the hemostatic effect of proximal ECA ligation is still controversial (1, 11). When a portion of the ICA must be resected, immediate vas- cular control and reconstruction are essential. On small tears, primary closure or patch angioplasty can be performed to repair them. In cases of ICA resection, it is necessary to perform inter- position graft or ECA transposition. The grafts used for carotid reconstruction include autologous grafts such as saphenous vein and femoral artery/vein, cryopreserved arterial homograft, and prosthetic graft using polytetrafluoroethylene (PTFE) or Dacron. During ICA clamping, carotid shunting can reduce the risk of stroke. Regarding vascular complications, an incidence of 2% to 13% has been reported for injury of ICA with or without reconstruc- tion (8, 9). The sacrifice of ECA and ICA has been performed as 13-33% and 11%, respectively (9). In our study, ECA liga- tion was performed on 39% of the patients, and ICA ligation with reconstruction on 23%. It was noted that the incidence of vas- cular complications was higher than previous literature because our cases included more advanced staged tumor with a relatively small number of total patients. Cerebrovascular complication such as stroke associated with or without manipulation of major neck vessels can occur, and its incidence has been reported to be 0 to 11% (9, 12). Postsurgical neurological complication such as CN deficit can occur, and the incidence of postoperative permanent CN deficit ranges from 6.9 to 42% (4, 8, 11, 12). The hypoglossal nerve (CN XII) and vagus nerve (CN X) appeared to be most vulnerable to injury from the sacrifice or retraction. In our study, the overall incidence of post- operative permanent neurovascular morbidity was 31%. Permanent CN deficit was found in 23% of the patients, and motality caused by stroke occurred in one patient. In terms of the relationship between Shamblin group and complication, all patients who had permanent neurovascular morbidity and carotid reconstruction were Shamblin III. These results also support the reports that the Shamblin classification can be used to estimate the postoperative neurovascular com- plications (6, 11), and early detection and prompt surgical resection of CBTs will decrease surgical morbidity. However, the Shamblin classification has some limitations because it does not reflect how deep tumor infiltrates through the wall of carotid vessels, which decides if it is possible to preserve the carotid ves- sels. Recently, Luna-Ortiz et al. (9) proposed modification of the Shamblin classification to make Shamblin IIIb which is clinically or histologically confirmed to infiltrate the adventitia regardless of tumor size. Initial diagnostic imaging studies usually include CT or MR imaging plus angiography. CT shows an avidly enhancing mass at the carotid bifurcation, and MR imaging depicts a mass with the characteristic “salt and pepper” appearance, especially in larger ones (1). Recently, it has been reported that contrast-enhanced MR angiography can be a noninvasive and quick diagnostic tool replacing catheter angiography for the assessment of head and neck paragangliomas (13). The goals of CBT angiography are to pro- vide a vascular road map for surgeons, search for multicentric synchronous tumors, and enable preoperative embolization for prophylactic hemostasis. Additionally, it could evaluate collat- eral arterial and venous circulation of the brain if an inevitable sacrifice of major vessels were necessary (1). There has been controversy concerning the usefulness of pre- operative embolization. Some authors prefer routine preopera- tive embolization because it can lower blood flow and decrease tumor size (14, 15). Others have found that selective preopera- tive embolization can facilitate tumor excision with less blood loss, particularly in larger tumors (Shamblin type II and III) (1, 4, 16, 17), while some groups disagree on preoperative routine embolization due to postembolization morbidity such as the poten- tial risk of stroke by embolic particles (4, 18). In our study, there was no significant difference in intraoper- ative blood loss and operation time between the embolization and non-embolization groups. These results suggest that the degree of invasion of tumors to the wall of carotid vessels and surgeon’s experience might be more important factors for intraoperative bleed- ing than the effects of embolization in selected cases. However, it was difficult to draw a conclusion on the effect of preoperative embolization because of the retrospective nature of this study and a relatively small number of patients who had undergone preoperative embolization. In conclusion, Shamblin III had a high risk of postoperative neurovascular complications. Therefore, early detection and prompt surgical resection of CBTs will decrease surgical mor- bidity. In addition, a team approach involving head and neck and vascular surgeons and interventional radiologists for the evaluation and management of these lesions will improve treat- ment outcomes.