The supraclavicular artery island flap in oral cavity reconstruction

The Supraclavicular Artery Island (SAI) fl ap is a regional fasciocutaneous fl ap which is raised from skin on the supraclavicular and shoulder area for reconstruction of head and neck defects. Mütter fi rst reported the application of medial-based random shoulder fl aps in 1842 [1]. In 1979, The supraclavicular artery fl ap was described by Lamberty as an axial fl ap [2]. Until the late 1990s, Pallua described a detailed anatomy of the blood supply to this fl ap [3]. In their study, the supraclavicular artery is a branch of the transverse cervical artery. The paired venae comitantes joint the transverse cervical vein or the external jugular vein. The origin of the fl ap artery is found in the triangle formed from the external jugular vein, the posterior border of the sternocleidomastoid muscle, and the clavicle. In 2009, Chiu applied the SAI fl ap to reconstruct the oncologic defects of the head and neck.


Introduction
The Supraclavicular Artery Island (SAI) fl ap is a regional fasciocutaneous fl ap which is raised from skin on the supraclavicular and shoulder area for reconstruction of head and neck defects. Mütter fi rst reported the application of medial-based random shoulder fl aps in 1842 [1]. In 1979, The supraclavicular artery fl ap was described by Lamberty as an axial fl ap [2]. Until the late 1990s, Pallua described a detailed anatomy of the blood supply to this fl ap [3]. In their study, the supraclavicular artery is a branch of the transverse cervical artery. The paired venae comitantes joint the transverse cervical vein or the external jugular vein. The origin of the fl ap artery is found in the triangle formed from the external jugular vein, the posterior border of the sternocleidomastoid muscle, and the clavicle. In 2009, Chiu applied the SAI fl ap to reconstruct the oncologic defects of the head and neck.
We have used the SAI fl ap for the head and neck defects after tumor ablation since 2012. The objectives of our study were to evaluate the advantages and disadvantages of the SAI fl ap in reconstruction of oral cavity defects.

Abstract
Objective: To evaluate the advantages and disadvantages of the SAI fl ap as an alternative for free fl ap in reconstruction of oral cavity defects.

Methods
We have a case series of 21 consecutive patients of squamous cell carinoma whose oral cavity were reconstructed by the SAI fl ap after tumor ablation. All reconstructive cases were performed from January 2018 through September 2019. We had 9 cases of T3 tumor and 12 cases of T4 tumor, and all of our patients with cervical lymph node metastases N1-2.
The Doppler probe is used to design the SAI fl ap based on the signals of the supraclavicular artery ( Figure 1). This artery begins at a point 7 cm from the sternal notch and 2 cm from the clavicle posterior border. The vessels reach the acromion tip and run toward the elbow.
Mean follow-up was 6.3 (range, 3-24) months. Surgical information collected included defect location and size, fl ap size, levels of neck dissection, and duration to harvest the fl ap. In addition, complications and survival rate of the fl ap were recorded (Table 1).

Results
The mean length of the SAI fl ap was 24.6 cm (range, 23 Citation: Nguyen  We had 6 patients (28%) with minor donor-site dehiscence, whereas larger dehiscence occurred in 2 patients (19%). The donor-site wound of these two patients requires prolonged wound care. We have no case in which severe limitations of arm movement was reported. We had 2 patients (19%) with partial skin fl ap necrosis, and one case (4.7%) with complete loss of the skin paddle. With total skin fl ap necrosis, in the case of total glossectomy, we have performed a second reconstructive procedure using pectoralis major fl ap.
Four patients of ours (16%) acquire the complication of salivary fi stula, all of the fi stulas recovered spontaneously.
All of our patients have accepted rehabilitation of speech and swallowing capacity (Figure 3).

Discussion
Among the choices of head and neck reconstruction, microvascular free fl ap is the standard of operation, the radial forearm fl ap and anterolateral thigh fl ap are considered the workhorse fl aps. Free-tissue transfer is very reliable and versatile but requires technical expertise and longer surgery duration.
Our initial experience with the SAI fl ap has revealed this fl ap to be available for reconstructing a variety of oral cavity defects. Niels Kokot, et al. have found the SAI fl ap to be safe, versatile, easy to harvest, and reliable for the head and neck defects [4]. Jay W. Granzow et al have supposed this fl ap to be thin, pliable fasciocutaneous regional fl ap [4].
According to the research of Niels Kokot on 45 patients, there are 8 cases (18%) of partial skin fl ap necrosis and 2 cases (4%) of total fl ap necrosis [3]. Our research has 9.5% partial fl ap necrosis and 4.8% total necrosis. Our SAI fl ap sizes are similar to those of the other authors [5].
The SAI fl ap has a long pedicle, so this fl ap can reach most of the oral cavity defects [6][7][8]. However, in some cases of complex three-dimensional defects, the SAI fl ap showed some shortcomings because of the rotational nature of the fl ap. If we try to stretch the fl ap to cover the defect, the tension combined with the rotation at the fl ap pedicle may compromise the distal skin paddle.

Conclusion
The SAI fl ap is reliable and versatile in reconstruction of oncologic defects of oral cavity and may be an alternative for free-tissue transfer in selected patients. However, the SAI fl ap has some disavantages because of its length and its rotational arc, so this fl ap is limited for some complex oral cavity defects.