4、DISCUSSION
Management of the carotid artery encased by tumor is an intraoperative challenge. Surgeons are very cautious in dissecting the tumor from the carotid artery when there is only extrinsic compression. Removal of the tumor in that setting with release of extrinsic compression reestablished blood flow to the brain. Although resection and ligation of the carotid artery is a classic option, there is a 17% to 79% risk of stroke1,7. Unlike ligation after carotid artery resection, the placement of a covered stent retains the normal carotid blood flow during surgery, and reduces the incidence of potential risk of cerebrovascular complications. Several previous reports suggested that en bloc resection of the tumor together with invaded segment of carotid artery followed by vascular reconstruction is an excellent option in management of advanced head and neck cancer5,7-8. However, in cases where the ICA close to the skull base is involved a reconstruction without special techniques like mandibulotomies may be difficult9. Comparing to immediate reconstruction following carotid artery resection, the covered stent may be more beneficial in cases with less optimal condition for vascular reconstruction, or the potential of R0 tumor resection. In difference to the cases reported by Markiewicz et al., which only invaded resection of the adventitia6, two of the cases reported by us invaded full thickness of the wall of carotid artery .The stent was placed intravascularly in the involved carotid artery, extended and passed beyond the site of tumor involvement, allowing the surgeon to completely resect the tumor along with involved vessel wall. It is well known that in some cases of recurrent advanced head and neck cancer, the tumor does not actually penetrate the artery wall, but is in the middle of the post-radiation scar tissue, and therefore cannot be resected without major blow-out risk. The tumor resection could still be complete with this approach.
The resection of recurrent advanced head and neck cancer is usually performed in a wide range and is prone to expose the airway or oropharyngeal mucosa. In addition, some patients have cervical tissue fibrosis caused by radiotherapy, leading to insufficient vascularity to local skin and muscle, which increases the possibility of postoperative infection and delayed wound healing10. Therefore, in this study, the pedicled pectoralis major musculocutaneous flap was used to repair the defect, which not only protected the exposed carotid artery, but also provided rich vascularity. Postoperative infection and delayed wound healing were not seen in any of our patients.
This approach could potentially achieve the maximal oncological resection without compromise of carotid artery blood flow. Although our limited experience with these five cases has demonstrated effective management using covered stent placement in patients with carotid artery encased by advanced head and neck cancer, long-term follow-up with a large number of patients is required to determine whether the carotid stent placement is superior to carotid artery ligation, resection and reconstruction, because of its potential benefit of minimizing intracranial vascular complications.