The era of modern thyroid surgery was introduced by Theodor Billroth and subsequently developed as a safe and effective procedure by Theodor Kocher, for which he was awarded the Nobel Prize in 1909. Since then, excision of the thyroid through a skin fold incision in the anterior neck just over the thyroid gland has been the Gold Standard treatment for a variety of thyroid pathologies. The open method provides good direct exposure that facilitates safe dissection and a quick operation with low morbidity and minimal mortality rates.
Despite this, some patients are left with a relatively prominent scar in the anterior lower neck, which affects the esthetic outcome and also can lead to cervical hyperesthesia and paresthesias. A large percentage of these patients include young people who are concerned about visible scars. Also, this is especially relevant in some Asian countries, such as Korea and Japan, where there is great cultural sensitivity to anterior neck scars. Furthermore, in some patients of darker-skin ethnicity, the traditional neck incision can result in hyperplastic and keloid scar formation in a highly visible area of the neck.
To deal with this issue, in recent decades attempts have been made to minimize surgical incisions or relocate them outside the neck. Endoscopic neck surgery for the thyroid and parathyroids was developed by Gagner and by Huscher et al. in 1996 and 1997 respectively. These innovative ideas launched further thyroidectomies and parathyroidectomies by many different institutions and surgeons, either performed as video-assisted or totally endoscopic procedures. Since then advances in endoscopic instrumentation, preoperative localization studies, and increased understanding of endoscopic cervical anatomy facilitated the growth of head-and-neck endoscopic surgery for the management of thyroid and parathyroid disease. Various methods have been developed to date by many surgeons, and its indications have been significantly expanded in recent years. Of all the remote access techniques, in this OC we will focus on the transaxillary thyroidectomy.
What is transaxillary thyroidectomy all about
There have been several reports of remote access techniques for thyroidectomy using surgical ports in different locations outside the neck, including the anterior chest wall, post auricular-occipital area, axillary region and sub-clavicular region. Although it requires patience and a particularly sophisticated skill set, the transaxillary approach, which was first described by Ikeda et al. in 2000, has been proved to be among the most feasible approaches.
The indications for transaxillary thyroidectomy should be the same as for conventional surgery. In general, the best candidates are nonobese (BMI < 30) young patients, without extensive comorbidities or advanced disease, with a history of keloid or hypertrophic scars, or otherwise motivated to avoid a cervical incision. This technique is not recommended in patients with a previous history of axillary surgery or irradiation.
Indications relating to the thyroid pathology include:
- Well-circumscribed nodule less than 3 cm diameter.
- Thyroid lobe smaller than 5–6 cm in the largest dimension.
- Underlying thyroid pathology with no evidence of thyroiditis on ultrasound.
Absolute contraindications include:
- Evidence of thyroid cancer with extrathyroidal extension or lymph node involvement.
- Graves’ disease.
- Substernal extension.
- Previous neck surgery.
Overall, the ideal patient is a patient with < 3 cm unilateral nodule who wishes to avoid a neck scar.
The patient is placed in supine position, with the neck slightly extended, and the ipsilateral arm on the side of the lesion placed at a 90º angle to the axis of the body, completely exposing the operative axilla.
The first 12 mm trocar for the endoscope is placed posterior to the anterior axillary line and under direct view a 5 mm trocar is introduced in a supra-areolar position. The plane is created, with blunt or sharp dissection, under the superficial platysma and leaving the pectoralis major muscle untouched in a lower plane. Carbon dioxide gas insufflation at 5 to 8 mmHg is used to maintain an optimal working space. Once enough space is obtained, another 12 mm trocar is introduced in the axillary level.
The dissection continues through the subcutaneous plane until the ipsilateral sternocleidomastoid muscle, which is the first landmark, is found. A plane between the sternocleidomastoid muscle and the sternohyoid muscle is dissected. Some surgeons use a fourth trocar to facilitate posterior retraction of the sternocleidomastoid muscle, while others divide the sternothyroid muscle to enlarge the working space.
At this point, the ipsilateral thyroid lobe should be exposed. Blunt dissection is performed at the inferior pole to isolate the recurrent laryngeal nerve (RLN) and the parathyroid glands. The vessels are then clipped and sectioned. The ligament of berry is divided while keeping the RLN in site to prevent injury. With the release of the posterior attachments of the thyroid to the trachea, the superior pedicle will be exposed and it can be divided close to the gland to avoid injury to the external branch of the superior laryngeal nerve. This allows for division at the isthmus from the contralateral lobe. The free and mobile lobe is then placed in an endobag for retrieval.
Advantages and disadvantages
This approach is associated with improved cosmetic outcomes when compared with open surgery, since what this technique proposes is to transfer the scars to an area that is concealed by clothing. Also, although there were initial concerns about the ability to identify and preserve the parathyroid glands and the RLN, it seems not to be a relevant issue in experienced hands. Moreover, visualization of these structures might be easier with the high degree of illumination and magnification provided by the endoscope within the closed operative space.
However, this technique has some non insignificant disadvantages. First of all, there is a much larger plane of tissue dissection, resulting in significantly more pain during the postoperative period and longer duration of surgery compared to conventional open thyroidectomy. Because of the extensive area of dissection, an element of subcutaneous emphysema and seroma can be expected, and thus it is advisable to use a suction drain postoperatively.
The working space is not particularly large. Subplatysmal pressure should be under 8 mmHg, due to the risks of CO2-related morbidity, such as hypercapnia, respiratory acidosis, tachycardia, air embolism, or inadvertent pneumothorax. To solve this problem some surgeons have described the use of skin hooks or an external retractor.
Also, the learning curve is steep because there is a need for familiarization with the “new anatomy” (the gland is lateral, which is not what we are used to).
1. Open thyroidectomy through a skin fold incision in the anterior neck just over the thyroid gland has been the Gold Standard treatment for a variety of thyroid pathologies, but during the last decades, attempts have been made to minimize surgical incisions or relocate them outside the neck to improve the esthetic outcome.
2. Of all remote access techniques, the transaxillary approach, which was first described by Ikeda et al. in 2000, has been proved to be among the most feasible approaches.
3. The indications for transaxillary thyroidectomy should be the same as for conventional surgery. In general, the best candidates are nonobese young patients, with < 3 cm unilateral nodule, and without history of axillary surgery or irradiation who wishes to avoid a neck scar.
4. This approach is associated with improved cosmetic outcomes when compared with open surgery, and it makes it easier to identify the parathyroid glands and the RLN because of the higher level of illumination and magnification provided by the endoscope within the closed operative space.
5. This technique has some non insignificant disadvantages, such as the larger plane of tissue dissection, the limited working space, and the steep learning curve.