An Experimental Study Of Covered Stent Combining With Surgery In The Treatment Of Head And Neck Cancer Invading Carotid Artery In Sheep Model

Objective: Head and neck cancer(HNC)is the sixth most common cancer and is the eighth leading cause of death in cancer worldwide.Head and neck cancer includes: oral carcinoma,salivary gland carcinoma,oropharyngeal carcinoma,hypopharyngeal carcinoma,laryngeal carcinoma,et al.Head and neck cancer includes various tumor types from different tissue cells and anatomical sites,of which more than 90% types are squamous cell carcinoma.The presence of metastatic cervical lymph nodes is the most important factor influencing the treatment and prognosis of head and neck cancer.In the literature,more than 50% of patients with head and neck squamous cell carcinomas are diagnosed with regional lymph node metastasis.Moreover,cervical lymph node metastasis reduced overall survival rate by nearly 50%.The carotid artery involvement is a potential result of advanced squamous cell carcinoma with lymph node metastasis in the head and neck cancer.In patients with advanced regional tumors,the carotid artery(common and/or internal)is invaded in 5 to 10% of cervical lymph node metastasis of head and neck squamous cell carcinoma.So a considerable number of patients,especially for advanced carcinoma,recurrent carcinoma,are found to have invaded the surrounding important blood vessels,which may not only cause carotid artery rupture,hemorrhage,and even death.The risk above caused by surgery is also enormous.It is reported in the literature that the main approaches of surgery include: the dissection of the outer wall of the carotid artery;the resection of tumor with the invaded carotid artery and ligation of the carotid artery;the resection of tumor with the invaded carotid artery and reconstruction of the carotid artery.At present,experts at home and abroad prefer to resect and reconstruct the carotid artery.The main advantage of the resection is clean andthorough,carotid artery and brain blood supply has been guaranteed.While the method of dissecting the outer wall of the carotid artery can take only in the patients without invading the elastic membrane.The ligation of carotid artery for the patient's is severe,even can cause paralysis and death.So it must be very cautious to apply.The reconstruction of carotid artery requires exquisite technique and strict conditions.In addition,although thoroughly removing of the tumor,the surgical complications cannot be ignored,such as rebleeding,thromboembolism,pseudoaneurysm,hemiplegia,et al.In recent years,the development of interventional technology to solve the problem of carotid artery provides a new method.The application of covered stent in vascular diseases of head and neck has become a popular hit.Some studies have reported the cases that the covered stent were used to save the patients who tolerated carotid artery rupture caused by advanced head and neck cancer,and these cases achieved good clinical effect.Our clinical application had also made a satisfactory immediate effect.However,the application of covered stent in head and neck cancer is limited to temporary hemostasis to save lives,and not completely removing the tumor.Based on this technique,we image carrying out a series of explorations in the affected area with covered stent to protect the blood supply,resect the tumor and invaded arterial wall,and achieve radical purposes.Firstly,to verify the feasibility and safety with covered stent replacing the carotid artery by animal experiment.This study,in the carotid artery model of sheep we placed the covered stent in the presumptive invaded carotid artery in advance,and then removed of the invaded artery,observed whether to occur postoperative bleeding and whether brain blood to be guaranteed.In the end achieving the purpose of radical resection and favorable survival state.Based on this hypothesis,the covered stent can cross the blood vessels at the break,and because of "membrane",the stent can play a role to "repair" to ensure the blood flow.On this basis,the stent can ensure the invaded artery normal blood flow after resection without leakage and bleeding.It will provide evidence support for the patients' temporary rescue who tolerated carotid artery rupturebecause of the tumor invasion,and with covered stent to achieve safe resection,improve clinical cure rate and long-term survival.Methods: The carotid artery from healthy sheep was used as a experimental model(which was closer to the normal human carotid artery diameter).The self-expandable covered stent was placed into the carotid artery through the common iliac artery,and then the part of the arterial wall covered by the covered stent was removed to observe whether the stent was stable or bleeding.Later,we used imaging equipment and surgery to observe whether the area of stent placed was bleeding or leak,and wether the stent was twist,loose or removed.Record the awareness and activities of the sheep.Result:1 Stent placementWe applied exploratory laparotomy to find the common iliac artery of the sheep,and successfully placed the self-expandable stent into the right common carotid artery using the catheter and wire through the common iliac artery.Postoperative observation did not find limb movement disorders,eating and behavioral abnormalities.Imaging equipment monitoring showed: stent placed stably,not loosing,no distortion and displacement,blood flowing stably.2 Surgical resection of part of the arterial wallThrough imaging positioning,found the section of covered stent and exposed it by surgery,then successfully resected part of the arterial wall of the stent covered(about 1cm),postoperative observation showed vital signs were stable,no hemiplegia,limb movement disorders and covered stent area did not occur bleeding and leak.Later,imaging equipment monitoring showed no bleeding and leak in the surgical area,stent maintaining stably,not loosing,no distortion and displacement.Conclusion:Through the experimental animal model,the experimental results consider that: 1,covered stent can be an immediate rescue to ensure the integrity of the carotid artery and blood flow in the patients of carotid arteryRupture.2,through the pre-implanted covered stent and surgical resection of the carotid artery in head and neck cancer,it can guarantee carotid artery flow and protect the brain blood supply to resect the tumor radically and extend the survival and quality of life for the patients undergoing carotid artery resection.This will provide safe and effective technique support for the treatment of carotid artery invasion in advanced head and neck cancer.