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.