Arterial microanastomoses on the reverse flow of the internal carotid artery reverse flow: an extreme solution in free-flap revascularisation. How we do it.

Microvascular free tissue transfer in head and neck reconstruction requires suitable recipient vessels, which are frequently compromised by prior surgery, radiotherapy, or size of the tumour. A surgical description of an arterial free flap pedicle anastomosis on the reverse internal carotid arterial flow in a vessel-depleted neck is presented. A 66-year-old male with a relapse of hypopharyngeal squamous cell carcinoma previously treated with both surgical and radiation therapy for carcinoma of the tongue and the larynx was successfully reconstructed using a free forearm flap with reverse internal carotid arterial flow. The involvement of the carotid glomus and prior surgery excluded the other vessels as recipients. The forearm free flap survived without any complications. This procedure can be considered an alternative rescue technique for salvage reconstruction in a vessel-depleted neck.

Introduction

To date, microvascular free-tissue transfer represents a reliable technique for reconstruction of defects following surgical treatment of head and neck cancer. Free tissue transfers have a high overall success rate, ranging between 91% and 99% of cases , and are generally performed with good functional and aesthetic outcomes, even considering donor-site morbidity . However, the procedure requires specific surgical skills, especially for management of the vascular pedicle. In particular, identification and preparation of recipient vessels and microsurgical vascular anastomoses are crucial steps in the field of reconstructive surgery . Meticulous attention to these points should be paid to avoid dangerous and life-threatening complications, and improve the overall success rate.

In fact, the management of vascular pedicles can be a troublesome aspect, especially in pre-irradiated graft beds, on the basis of vascular fibrosis and endothelial thickening. In addition to this, surgeons faced with free-flap reconstruction have to be trained, to modify in itiner during a radial forearm flap set up for reconstruction following resection of a relapsing hypopharyngeal tumor in an irradiated patient.

Clinical techniques and technology

A microvascular transfer of the radial forearm was planned to reconstruct the digestive tract in a 66-yearold man with a relapsing hypopharyngeal squamous cell carcinoma (SCC). The patient's relevant history began 14 years before when he underwent a partial glossectomy with bilateral functional neck dissection for an undifferentiated SCC, followed by post-operative radiotherapy. In July 2010, a total laryngectomy was performed for the development of an undifferentiated SCC in the left pyriform sinus, extending to the homolateral larynx.

The patient was also affected by arterial hypertension and chronic obstructive pulmonary disease.

For the tumour recurrence in the residual hypopharyngeal lateral left wall (Fig. 1), also considering his previous irradiation history, surgery was therefore planned. An en bloc tumour resection englobing the proximal portion of the involved common carotid artery at the level of the carotid artery bifurcation (previously undetected to the pre-operatory radiologic assessment) was performed, and a right fascio-cutaneous radial forearm flap was set up and tubulised for reconstructive purposes (Figs. 1, 2).

Fig. 1.

Ablation.

Fig. 2.

Reconstruction. T: tongue; IJV: internal jugular vein, C: carotid artery.

Due to the lack of appropriate arterial flow on the arteries tributary to both the ipsilateral and contralateral external carotid artery, the reversed flow in the distal portion of the left internal carotid artery was used for arterial microanastomoses. Venous microanastomosis was performed between the right tyreo-linguo-facial venous trunk and the cephalic donor vein.

A left pectoral muscle flap was then transposed to protect the residual carotid artery, and a cutaneous Tiersch graft taken from the anterolateral left thigh was used to cover the residual donor site defect.

Discussion

To date, microsurgical reconstruction of the head and neck after oncological surgery based on free flaps is, in experienced hands, an effective and successful technique . The most common used recipient vessels for arterial microanastomoses are the branches of the external carotid artery, such as the facial, superior thyroid, and lingual arteries. However, it is generally accepted that each artery having, once resected, any pulsatile and adequate flow at its distal end can be used as a recipient vessel .

However, in managing head and neck reconstruction, surgeons must be ready to modify in itinere their reconstructive strategy on the basis of unexpected anatomic extension of the disease (e.g. vascular involvement) or impairment of vascular structures suitable for microanastomoses due to unsuspected flow obstruction or reduced vascular flow (e.g. related to atheromatous disease, postattinic atherosclerosis, or, less frequently, to intimal injury after the positioning of intra-arterial infusion catheter). In addition to these, some technical difficulties may arise, including troublesome pedicle management due to limited pedicle length, reduced vessel caliber or kinking of the pedicle . In order to overcome these pitfalls, some authors have suggested that interposition of venous grafts can be used to reach an adequate pedicle length. However, it must be pointed out that surgical strategies using fragile and thin-walled vessels such as graft veins may predispose to intravascular thrombosis.

Therefore, under unexpected and unfavourable conditions, aside from other less effective reconstructive techniques such as delayed locoregional flaps , the use of reverse arterial flow can be considered as an extreme surgical choice. In fact, Neligan and co-workers described 28 cases of superior thyroid and facial artery reverse flow used for free flap revascularisation with good clinical outcomes . These positive results may be related to adequate arterial flow, corresponding to 57-76% of systemic arterial pressure as documented by clinical and physiopathologic studies . In addition to this, Batchelor stated that the distal flow of an extracranial reverse flow vessel would be enhanced by recruitment of its peripheral capillary branches resulting in overflow leading to an adequate flap blood supply. At any rate, it may be speculated that the above mentioned conditions related to extracranial reverse flow recipients would be valid in case of intracranial vessels, thus leading to a successful outcome such in this case. However, to our knowledge, no previous descriptions of arterial microanastomoses performed on the reverse flow of the internal carotid artery have been reported.

With regards to the donor site, forearm free flaps should be considered as the preferred choice compared to perforator flaps in such difficult situations, on the basis of their long and well-caliber pedicles . Indeed, in our patient, the forearm flap allowed us to reach the distal portion of the inner carotid artery and use its reverse flow for revascularisation. Moreover, the large size of the radial artery used achieved a good matching with the most of the secondary arterial neck branches and even with the internal carotid artery. In addition to this, a long pedicle is useful when contralateral arterial supply management is required, as in our report, due to impaired patency of the ipsilateral arterial.

In conclusion, microvascular surgery in vessel-depleted necks is a challenge and somewhat troublesome aspect. The case presented herein suggests the feasibility of internal carotid artery reflow for free flap revascularisation when no other safer or easier technical options are possible.