Lim J-Y et al.: Surgical Treatment of Carotid Body Paragangliomas 93 in the left. Two patients (15%) had bilateral CBTs. A multicentric paraganglioma not from the head and neck was discovered in one patient (8%) who had a cardiac paraganglioma. No patient had a family history of paraganglioma. The most common symptom was a pulsatile neck mass without CN deficit. No patient had function- ing CBT that presented with palpitations, tachycardia, and hyper- tension accompanying elevated catecholamine level. Preoperative CN X dysfunction was observed in 1 patient (8%). CT and MR imaging revealed enhancing mass splaying the ICA and ECA of the carotid bifurcation (Fig. 1), and the medi- an tumor size of 13 CBTs was 3.6 cm (range, 2 to 5.5 cm). One tumor (8%) was Shamblin class I, four (31%) were class II, and eight (61%) were class III. The ascending pharyngeal artery was a major feeding artery for tumors. Tumor embolization was performed on six patients (46%) with polyvinyl alcohol particles after superselection of feeding arteries. The others were unable to undergo embolization because they had numerous feeding arteries that could reduce the effect of embolization and the potential high risk of cerebral infarction by embolic particles. No patient demonstrated complications following angiography or embolization. Tumor size and Shamblin group was not significantly different between the embolization and non-embolization groups (P>0.05). The median intraopera- tive blood loss was 400 mL (range, 200 to 1,200 mL) in the embolization group and 550 mL (range, 200 to 1,400 mL) in the non-embolization group. The median operation time was 360 minutes and hospitalization was 8 days for both groups. These parameters of the embolization group were not signifi- cantly reduced compared to the non-embolization group (P>0.05) (Table 1). According to the Shamblin classification, the median tumor size was 2.3 cm (range, 2 to 3.5 cm) in Shamblin I and II and 4 cm (range, 3.2 to 5.5) in Shamblin III (P=0.005). The median Table 1. Comparison of embolization (I) and nonembolization group (II) Group I (n=7) Group II (n=6) P-value Shamblin group Tumor size (cm) Estimated blood loss (mL) Operation time (min) Hospitalization (days) 4 type II, 3 type III 1 type I, 5 type III 3.5 (2.2-5.5) 3.9 (2-5.5) 400 (200-1200) 550 (200-1400) 360 (180-540) 8 (4-12) 360 (220-480) 8 (6-10) Table 2. Surgical records of tumors according to Shamblin group Tumor size (cm) Estimated blood loss (mL) Operation time (min) Hospital stay (days) Shamblin I and II (n=5) 2.3 (2-3.5) 280 (200-400) 240 (180-360) 8 (8-11) Shamblin III (n=8) 4 (3.2-5.5) 700 (500-1400) 420 (220-540) 8 (4-12) 0.151 0.829 0.386 0.943 0.828 P-value 0.005 0.003 0.019 0.524 intraoperative blood loss was 280 mL (range, 200 to 400 mL) in Shamblin I and II and 700 mL (range, 500 to 1,400 mL) in Shamblin III (P=0.003), and operation time, including ICA reconstruction time, was 240 min (range, 180 to 360 min) and 420 min (range, 220 to 540 min), respectively (P=0.019). Hospitalization was 8 days in both groups (Table 2). The ECA was ligated in five patients (39%) during operation. After tumor resection, small tears in the ICA in two patients who belonged to Shamblin II and III, respectively, were repaired pri- marily. A portion of the ICA had to be resected in three patients (23%), and they all belonged to Shamblin III (38%). Of the three cases with ICA resection, saphenous vein interposition was performed on two patients and prosthetic vascular graft interposition on one patient (Table 3). One patient (8%) had transient cerebral ischemia immediate- ly after operation that was likely associated with manipulation of the ICA during vascular reconstruction. One patient (8%) died of postoperative intracranial hemorrhage after thromboly- sis for ICA thrombosis. These complications were all observed in Shamblin III (25%). Postoperative CN deficits developed in five patients (39%) immediately after surgery, and they all belonged to Shamblin III (63%, P=0.03). They included three CN X, one CN XII, and one superior laryngeal nerve. Two of them who had CN X deficits recovered within 6 months, and postoperative permanent CN deficit occurred in three patients (23%). One patient presented with preoperative CN X dysfunction demonstrated postopera- tive permanent vocal fold paralysis and eventually underwent Table 3. Postoperative neurovascular complications according to Shamblin group Shamblin I and II (n=5) Shamblin III (n=8) Vascular repair Primary closure Saphenous vein graft Prosthetic vascular graft Stroke Transient Permanent Postoperative CN deficit IX X XI XII Sympathetic nerve Superior laryngeal nerve 1 (8) - - - - - - - - - - 1 (8) 2 (15) 1 (8) 1 (8) 1 (8)* - 3 (23) - 1 (8) - 1 P-value 0.299 0.243 0.03 Values are presented as number (%). CN: cranial nerve. *Postoperative intracranial hemorrhage after thrombolysis of internal carotid artery thrombosis caused by postoperative hematoma compres- sion. Vagus nerve paralysis; two patients had transient vocal fold paraly- sis and one patient had permanent vocal fold paralysis.