Tongue viability after bilateral lingual artery ligation and surgery for recurrent tongue-base cancer.

Abstract

A 73-year-old man came to us with a second primary tumor of the tongue base. He had undergone a total laryngectomy, neck dissections, and radiation for squamous cell carcinoma of the glottis 25 years earlier. Surgery was performed, including a subtotal tongue-base resection and pectoralis myocutaneous flap reconstruction. Intraoperative findings confirmed tumor involvement of the left lingual artery and hypoglossal nerve, both of which were sacrificed. Dissection revealed an intact but apparently thrombosed right lingual artery, and this was verified by intraoperative Doppler evaluation. Postoperatively, the preserved oral tongue remained well perfused and viable, and tongue mobility was good. In patients who have undergone previous head and neck cancer resections, collateral blood supply to the tongue might develop if the flow of one or both of the lingual arteries is interrupted. This possibility can be fully evaluated by preoperative angiography, which might offer these patients the potential for tongue preservation.

Introduction

The tongue is a muscular organ suspended by its intrinsic muscles, which are attached to the surrounding skull base, mandible, and hyoid bone. Its rich blood supply provides it with a resistance to infection and allows lacerations and incisions to heal quickly. Most of the tongue's blood is supplied by the lingual arteries; only minor contributions are made by the facial, inferior alveolar, and buccal arteries. (1) Therefore, it is a well-accepted surgical principle that simultaneous sacrifice of both lingual arteries will critically compromise blood flow and lead to ischemic necrosis of the entire tongue. (2) Preservation of just one of the lingual arteries is sufficient to maintain adequate tongue vascularity from crossover perfusion by the contralateral lingual artery.

In this article, we describe the case of a patient with recurrent squamous cell carcinoma of the base of the tongue following previous laryngectomy and bilateral neck dissections. Surgical resection required ligation of both the right and left lingual arteries, but the preserved oral tongue remained viable. We review the possible explanations for this fortunate outcome.

Case report

A 73-year-old man came to us with a complaint of dysphagia. He had undergone a total laryngectomy, bilateral neck dissections, and radiation therapy for a squamous cell carcinoma of the glottis 25 years earlier. Computed tomography (CT) revealed a predominately leftsided base-of-the-tongue mass (figure 1). Endoscopic examination confirmed tumor involvement of approximately 75% of the tongue base, and biopsies were positive for a second primary infiltrating squamous cell carcinoma.

[FIGURE 1 OMITTED]

Surgical resection was performed, including a subtotal tongue-base resection and pectoralis myocutaneous flap reconstruction. The patient was advised that sacrifice of the lingual arteries and hypoglossal nerves bilaterally might be required in order to achieve complete tumor resection, and consent was obtained for possible total glossectomy.

Intraoperative findings confirmed tumor involvement of the left lingual artery and the left hypoglossal nerve. Dissection revealed an intact but apparently thrombosed right lingual artery, which was verified by intraoperative Doppler evaluation. This artery was somewhat more distant from the tumor mass and did not appear to be thrombosed by direct tumor invasion. The left lingual artery, whose intact flow was also verified on Doppler imaging, was clamped prior to ligation, and the anterior (oral) tongue remained well vascularizcd with excellent capillary refill.

The right and left lingual arteries were subsequently ligated and divided, and resection of the subtotal tongue base with preservation of the right hypoglossal nerve was completed. The pharyngeal and tongue-base defects were reconstructed with a pectoralis myocutaneous flap. Postoperatively, the preserved oral tongue remained well perfused and viable, and tongue mobility was good (figure 2). Evaluation of the vascular supply to the tongue was attempted with magnetic resonance angiography, but the resolution was insufficient to determine the presence or absence of lingual arteries or other contributors. The health risks of standard angiography were deemed to be too high to warrant its use in this patient.

Discussion

Several authors have highlighted the importance of the contralateral blood flow to the tongue. This might become apparent only after ligation of the ipsilateral lingual or external carotid artery. Maloney et al showed that in dogs, the contralateral lingual artery supplied the ligated side 71% of the time, despite the lack of apparent crossover before ligation, as measured by dye distribution. (3) in the other 29% of cases, dye was distributed ipsilaterally to the side of carotid artery injection despite ligation of the lingual artery on the injected side, implying ipsilateral collateral contributions. Webb et al demonstrated that perfusion of both sides of the tongue in rabbits who had undergone unilateral ligation of the common carotid artery was indistinguishable from that of controls 1 week postoperatively. (4) Gotze and Lierse performed a similar study in rabbits, and at no time was the ligated side of the tongue necrotic or compromised sufficiently to result in any ultrastructural changes. (5)

In our patient, perhaps the most likely explanation for the survival of the oral tongue is that ipsilateral collateral circulation developed to the right side of the tongue some time following the thrombosis of the right lingual artery. His right lingual artery was seen to be thrombosed without evidence of direct tumor invasion, so it is probable that thrombosis of this vessel occurred at the time of his original laryngectomy 25 years earlier. Although the vascularity of the tongue would have been preserved initially by a contralateral blood supply from the left lingual artery, the development of ipsilateral collateral circulation to the right side over several years seems likely. Possible sources of these collaterals are the minor suppliers--that is, the facial, inferior alveolar, and buccal arteries. They might have been stimulated to increase and broaden their contribution to the tongue following ligation or thrombosis of the right lingual artery.

Had our patient had no history of surgery, it is far less likely that we would have achieved such a fortunate outcome after bilateral lingual artery ligation. In patients with tumors that involve both sides of the tongue base who have undergone extensive prior surgery (such as total laryngectomy or radical neck dissection), the anticipated loss of both lingual arteries during tumor resection may not result in ischemic necrosis of the remaining oral tongue if one of the lingual arteries has already been ligated. A preoperative angiogram would demonstrate patency of the lingual arteries and the presence of external carotid artery collateral circulation if one lingual artery had been ligated. Although this evidence would not ensure the viability of the oral tongue following bilateral lingual artery ligation, the outcome of our case suggests that this is at least an encouraging possibility. Our findings may serve as useful information to aid patients in making difficult decisions about proceeding with surgical resection when few, if any, other curative options remain.

References

(1.) Houseman ND, Taylor GI, Pan WR. The angiosomes of the head and neck: Anatomic study and clinic applications. Plast Reconstr Surg 2000; 105:2287-313.

(2.) Myers EN. Operative Otolaryngology-Head and Neck Surgery. Philadelphia: W.B. Saunders, 1997:229.

(3.) Maloney PL, Doku HC, Shepherd NJ. Collateral circulation after ligation of the lingual artery in dogs. J Oral Surg 1969;27:395-7.

(4.) Webb JG, Jr., Nelson J F, Koudelka BM. Collateral circulation in the rabbit tongue after common carotid ligation. J Oral Surg 1979; 37:398-401.

(5.) Gotze W, Lierse W. [The blood vessels of the rabbit tongue, contralateral anastomoses of both halves of the tongue and their efficacy following unilateral ligation of the lingual artery or the external carotid artery]. Gegenbaurs Morphol Jahrb 1969;113: 453-61.

From the Department of Otolaryngology, University of Miami School or Medicine.

Reprint requests: Donald T. Weed, MD, Department of Otolaryngology, School of Medicine, University or Miami, 1475 NW 12th Ave. #4037, Miami. FL 33136. Phone: [phone]; fax: [phone]; e-mail: [e-mail]