Complete transposition of carotid bifurcation: can it be an additional risk factor of injury to the cranial nerves during carotid endarterectomy?

Abstract

The internal carotid artery (ICA) usually, lies posterolaterally to the external carotid artery (ECA). Sometimes a complete carotid transposition can occur, with the ECA in a lateral position and the ICA on the medial side can occur. Our study evaluated the significance and impact that this anomaly may have on cranial nerve injuries. From January 2008 to November 2010, 296 patients underwent 360 consecutive primary carotid endarterectomy (CEA) procedures. During carotid isolation, we detected an unexpected lateral position of the ECA in 11 cases (3.6%). χ(2) analysis and the Student's t-test were used to compare the incidence of cranial nerve injuries between the 11 patients with the lateral ECA who underwent CEA (group A) and 11 randomized patients with a normal bifurcation (group B). Statistical significance was inferred at χ(2)>3.84 and P<0.05. A statistical difference in the incidence of superior laryngeal nerve paralysis was detected between groups A and B (18.1%, 2/11 in group A vs. 0%, 0/11 in group B; χ(2)>3.84; P<0.05). No differences in incidence of injury were detected for the other cranial nerves. A very meticulous mobilization of the ECA and ICA is needed to perform CEA, but superior laryngeal nerve injury can occur despite the use of a safe and meticulous surgical technique.

Analysis of twisted internal carotid arteries in carotid endarterectomy

“…[3,4,7,10] is anomaly was also called "side-by-side carotid artery, " "dorsal/dorsomedial origin of the ICA, " or "lateral ECA. " [5,[12][13][14][15][16]20] Although several series and/or cases have been reported, we clarified the frequency and other clinical features of the twisted ICAs among our CEA-treated cases and…”

Diagnosis and Operative Management of Carotid Endarterectomy in Patients with Twisted Carotid Bifurcation

“… 4) However, the anatomical relationships between the ECA and ICA of patients scheduled to undergo CEA have never been evaluated by CCE. 5) …”

“…Angiography findings have shown that the incidence of TCB or LPECA in various diseases is 4.3%-4.9% in Japanese populations 10,12) and 3.6%-15.1% during CEA. [5][6][7][8]10,14,15) Therefore, this abnormality is actually quite prevalent.…”

“…4) However, the anatomical relationships between the ECA and ICA of patients scheduled to undergo CEA have never been evaluated by CCE. 5) The ICA location can be easily confirmed by BB-MRI because its diameter is larger than that of the ECA. Furthermore, plaque in the ICA frequently presents as hyperintense regions on BB-T1-weighted MRI.…”

“…The external carotid artery (ECA) is usually located medially to the ipsilateral internal carotid artery (ICA) at the level of the common carotid artery (CCA) bifurcation. However, the ICA sometimes runs medically to the ECA, which has been described as side-by-side carotid artery, 3) dorsal/dorsomedial origin of the ICA, 4) complete transposition of the carotid bifurcation (CB), 5) twisted carotid bifurcation (TCB), [6][7][8] lateral ECA, and lateral position of the ECA (LPECA). [9][10][11][12] Most recent reports of patients with TCB who have undergone CEA have focused on surgical techniques, and few describe diagnosing a TCB.…”