Journal of Minimal Access Surgery

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Year : 2016  |  Volume : 12  |  Issue : 1  |  Page : 63--67

Single-port unilateral transaxillary totally endoscopic thyroidectomy: A survival animal and cadaver feasibility study

Henrique Neubarth Phillips1, Rossano Kepler Alvim Fiorelli2, Marcelo Rios Queiroz3, Andre Lacerda Oliveira3, Ricardo Zorron4,  
1 Department of Surgery, Hospital Municipal Miguel Couto, Rio de Janeiro, Brazil
2 Department of Surgery, Hospital Universitário Gaffre-Guinle, Rio de Janeiro, Brazil
3 Department of Post Graduation, Universidade Estadual Norte Fluminense, UENF, Rio de Janeiro, Brazil
4 Innovative Surgery Division, Klinikum Bremerhaven Reikenheide, Bremerhaven, Germany

Correspondence Address:
Henrique Neubarth Phillips
Hospital Universitário Gaffrée e Guinle, Rua Mariz e Barros 775, Rio de Janeiro, RJ


Background: Single-port unilateral axillary thyroidectomy has great potential to become a valid alternative technique for thyroid surgery. We tested the technique in a study on live animals and cadavers to evaluate the feasibility and reproducibility of the procedure. Materials and Methods: Institutional review board (IRB) approval was obtained in our university by the Council of Ethics for the study in surviving animals and cadavers. Subtotal thyroidectomy using unilateral axillary single port was performed in five dogs and five cadavers. Performing incision in the axillary fossa, a disposable single port was inserted. The dissection progressed for creating a subcutaneous tunnel to the subplatysmal region; after opening the platysma muscle and separation of the strap muscles, the thyroid gland was identified. After key anatomical landmarks were identified, the dissection was started at the upper pole towards the bottom, and to the isthmus. Specimens were extracted intact through the tunnel. Clinical and laboratorial observations of the experimental study in a 15-day follow-up and intraoperative data were documented. Results: All surgeries were performed in five animals which survived 15 days without postoperative complications. In the surgeries successfully performed in five cadavers, anatomical landmarks were recognised and intraoperative dissection of recurrent nerves and parathyroid glands was performed. Mean operative time was 64 min (46-85 min) in animals and 123 min (110-140 min) in cadavers, with a good cosmetic outcome since the incision was situated in the axillary fold. Conclusion: The technique of single-port axillary unilateral thyroidectomy was feasible and reproducible in the cadavers and animal survival study, suggesting the procedure as an alternative to minimally invasive surgery of the neck.

How to cite this article:
Phillips HN, Fiorelli RK, Queiroz MR, Oliveira AL, Zorron R. Single-port unilateral transaxillary totally endoscopic thyroidectomy: A survival animal and cadaver feasibility study.J Min Access Surg 2016;12:63-67

How to cite this URL:
Phillips HN, Fiorelli RK, Queiroz MR, Oliveira AL, Zorron R. Single-port unilateral transaxillary totally endoscopic thyroidectomy: A survival animal and cadaver feasibility study. J Min Access Surg [serial online] 2016 [cited 2019 Nov 17 ];12:63-67
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Full Text


Since Kocher first described thyroidectomy in 1874, this particular neck surgery has undergone a few modifications. With the beginning of laparoscopy surgery, surgeons have made efforts to achieve an ideal neck procedure that is safe, feasible and less painful and with a good cosmetic outcome. Only in the late 90s, the minimally invasive neck surgery started to get clinically developed, [1],[2],[3] and since then, a lot of new techniques have been proposed. Among other technical propositions, minimally invasive video-assisted thyroidectomy (MIVAT) described in the 90s by Miccoli has been the most commonly used method till date. [4],[5]

Along with these new techniques, many questions arose about the safety of this kind of minimally invasive surgery. So, more research papers were published, some comparing open versus endoscopic surgery. [6],[7],[8],[9],[10],[11],[12],[13],[14],[15] The axillary approach was then used as an alternative for hiding the scar, however, three trocars were necessary to access the thyroid gland by the axillo-bilateral-breast approach (ABBA), creating a wide dissection and, thus, being a potential risk for complications. [16],[17],[18],[19],[20],[21]

Modern laparoscopy aimed to further minimise the access by recent achievements made in natural orifice surgery and single-port surgery, mostly by reducing the number of access sites using recent technology. In the search of a new and reproducible minimally invasive surgery, our group tested unilateral transaxillary single-port access as a potential procedure for thyroidectomy and parathyroidectomy. This study describes the application of this technique in a live animal and cadaver study.

 Materials and Methods

The research was performed in collaboration with Universidade Estadual do Norte Fluminense UENF, and Hospital Universitário Gaffrée e Guinle, UNIRIO, Rio de Janeiro. The institutional review board (IRB; Ethics Committee CEP HUGG number 96/2011) gave approval for performing single-port transaxillary thyroidectomy in cadavers. The research group consisted of a multidisciplinary team of surgeons and veterinary surgeons. A veterinary hospital facility was available and single-port technical possibilities were tested in the animal model by the study team. Conversion to open surgery was pre-defined as any neck incision made for dissection or specimen retrieval.

For the animal survival study, Ethics Committee approval (UENF, 2011) was obtained for testing the technique in five dogs. Unilateral transaxillary lobectomy plus isthmectomy was performed in five animals in the University of Norte Fluminense Veterinary Hospital in August 2011.

As the next step, lobectomy plus isthmectomy was performed in five cadavers in Universidade Federal do Estado do Rio de Janeiro between August 2011 and September 2012. Exclusion criteria were cadavers with previous neck procedures and body mass index (BMI) >30 kg/m 2 .

Operative procedure

Animal survival study

All five animals were positioned in dorsal decubitus with forelegs opened, exposing the axillary region. The viewing monitor was placed above the animal's head, with the surgeon and the camera operator standing at the lesion side. All animals were subjected to general anaesthesia and raqui anaesthesia with 0.5% Marcaine. A 2 cm incision was made in the axilla and the subcutaneous tissue was dissected with a Kelly forceps. Then a 5 mm trocar was inserted, and CO2 was insufflated at a pressure of 8 mmHg to avoid subcutaneous emphysema. The initial subcutaneous tunnel was gently created by the 5 mm camera. After that, a disposable single-port device (Olympus Triport; Olympus OSTE, Hamburg, Germany) was installed and the achievement of thyroid field was made through the sternocephalic muscle until reaching the trachea, by blunt and cutting dissection with laparoscopy instruments [Figure 1]a, b. The thyroid gland was identified and dissected from the bottom to the top, identifying preserving the recurrent laryngeal nerve, using monopolar shears. Then lobectomy was performed and the specimen was retrieved intact through the tunnel.{Figure 1}

Cadaver study

The five fresh cadavers, three female and two male, were placed in the supine position with the neck moderately extended and the lesion-side arm was stretched out at 90° if possible due to cadaver rigidity. The viewing monitor was placed above the cadaver's head, with the surgeon and the camera operator standing at the lesion side. A 2.0-cm-long incision was made parallel to the skin folds on the anterior axillary line of the lesion side and a subcutaneous tunnel from the axilla to the anterior neck area was dissected over the anterior surface of the pectoralis major muscle and clavicle by a Kelly clamp instrument [Figure 2]a.{Figure 2}

Through this incision, an Olympus Triport (Olympus OSTE, Germany) was installed. CO2 was insufflated at a pressure of 8 mmHg into the port to provide a working space [Figure 2]b. A Karl Storz 5 mm, 30° rigid scope was inserted, and blunt dissection was performed using the tip of the camera with the help of CO2 expansion. We used only 5 mm straight instruments. After passing the superior surface of the medial border of the sternocleidomastoid muscle and through the platysma muscles, scissors were used to widen the subcutaneous cavity between the platysma muscle and the strap muscle. The lesion-side thyroid lobe was reached by vertical dissection of the strap muscle in the middle line [Figure 2]c. In two cadavers, a percutaneous suture was also done to allow strap muscle retraction.

Sharp dissection of the inferior pole was performed with monopolar scissors, identifying and ligating the inferior thyroid artery, using a metalic clip. After treating the inferior pole, we continued towards the superior pole, passing through the medial thyroid vein. The operation progressed identifying the recurrent nerve and frequently the parathyroid glands [Figure 2]d. At the superior pole, using a forceps for retraction, dissection was performed close to the gland, avoiding injuries to the superior laryngeal nerve; then the superior pole was ligated. The isthmus of the thyroid gland was dissected and resected from the trachea using scissors. The specimen was retrieved through the incision [Figure 3]a. The incision was closed with an absorbable intracutaneous suture.{Figure 3}


Unilateral thyroidectomy was successfully performed in all animals and cadavers and there was no conversion to open surgery. The mean operative time for animal cases was 64 min (46-85min); mean time to form the tunnel and operating field in animals was 29 min (19-45 min) [Table 1]. All animals have had 15 days of survival and no complications were documented on follow-up by the veterinarian.{Table 1}

In the study with cadavers, the mean time to form the tunnel and operating field was 52.8 min (43-61 min) and the mean operative time was 123 min (110-140 min) [Table 2]. In all cases, it was possible to identify the paramount structures such as sternocleidomastoid muscle, prethyroid muscles, superior and inferior parathyroid glands (ipsilateral), recurrent nerve (ipsilateral), thyroid lobe and isthmus. Final cosmetic result was satisfactory [Figure 3]b.{Table 2}


The present study shows the feasibility of neck surgeries, such as thyroidectomy and parathyroidectomy, through a unilateral single-port device. From the pioneering work of Gagner, who performed an endoscopic subtotal parathyroidectomy in 1996, [1] many surgeons started to search a better way to do neck procedures endoscopically, especially trying to avoid visible scar as in open surgery that could cause hypertrophic scarring. After the upcoming new techniques, although with good clinical results, the adoption of endoscopic neck procedures poor, probably because of difficult learning curve, limited training and proctoring possibilities.

MIVAT was described by Miccoli et al. in 1997 [4] and a number of larger series studies have been studied to date. The MIVAT technique consists of a 2 cm incision in the neck anteriorly with laparoscopic assistance. In a retrospective multicentric study with 336 patients with a complication rate of 7% transient and 1% permanent recurrent nerve paralysis (RNP) (0.3%), nine transient and two permanent hypoparathyroidism (0.67%). [5] Disadvantage of the method is the cervical localisation of the scar, large specimens cannot be retrieved, and it is not possible to perform lymphadenectomy in the central compartment. The literature considers that the main indication for MIVAT should be benign disease.

Aiming the goal of no-scar surgery, Witzel et al. tested in animals natural orifice translumenal endoscopic surgery (NOTES) sublingual transoral access for thyroid surgery. [22] In their article, they mention that it is easier to perform the surgery in animals due to their anatomy. Benhidjeb et al. performed similar study in cadavers, but also using transoral robotics. [23],[24] Wilhelm et al. published an initial series of eight patients, with an extremely high rate of complications such as permanent palsy of the right recurrent laryngeal nerve and paraesthesia of the mental nerve. [16] There were some limitations at the procedure concerning the specimen volume and nodule size.

In another study on NOTES, Nakajo et al. reported a transoral premandible approach to thyroidectomy in a series of eight patients. [25] Unlike other kinds of access, the dissection of the working space was performed with instillation of epinephrine diluted with saline solution for reduction of bleeding. After dissection of the subplatysmal plane, and percutaneous insertion of two Kirschner wires for retraction, they noticed that the working space was wider than with CO 2 , avoiding postoperative subcutaneous emphysema. In this small series, thyroidectomy could be performed for Graves, nodular goitre and papillary microcarcinoma without evidence of lymph node metastases. Special attention has been given for thermal damage of the mental nerve, by avoiding manipulation of the mental foramen. Heat was avoided during subcutaneous area of the chin. Postoperative results showed several cases of sensory disorder around the chin for more than 6 months. Another problem of the transoral technique is potential infection of the local access, as the oral cavity is almost impossible to sterilise, adding contamination to a normally sterile cervical compartment. Further studies might show whether abscess formation is a likely problem with transoral thyroid surgery.

Lee et al. idealised the unilateral single-incision endoscopic thyroidectomy by the axillary approach. [26] In their study with four patients, they used a self-made single-port system using an Alexis® retractor (Applied Medical, Rancho Santa Margarita, CA, USA) and a glove, inserting three 5 mm trocars into 1 st , 3 rd , and 5 th fingers, fastened with silk sutures. To create the subcutaneous space, they used an acrylic bar and CO 2 gas insufflating up to 4-6 mmHg pressure. A 5 mm flexible scope was used together with a harmonic scalpel. The dissection was made identifying the medial border of sternocleidomastoid muscle, separating from the strap muscle and using a 2.0 percutaneous absorbable suture to retract it superiorly. Mean of the operative time was 160 min; excellent cosmetic result was obtained with no complications. Fan et al. from China also reported a series of four cases of single-port thyroidectomy using a SILS port (Covidien, New Haven, CT, USA) and harmonic scalpel, with an average operative time of 92.5 min and with no complications. [27] The postoperative pain score assessed by visual analogue scale was 1 in 10 on the first postoperative day for all patients.

Robotic unilateral access was proposed by Kang [27] and his clinical series showed feasibility and safety of the procedure. Limitations of the robotic technique are the cost of the equipment, special robotic training, the fact it is not accessible for surgeons in general, and a still bigger incision necessary. Lee also compared endoscopic and robotic thyroidectomy. [28] In his paper, he compared 96 patients in the endoscopic group and 163 patients in the robotic one. Both patient groups had similar operative time, hospitalisation period, and intraoperative blood loss. Robotic thyroidectomy needed a shorter learning curve to accomplish a satisfactory result, and had 12.5% transient hypocalcaemia, whereas endoscopic thyroidectomy had none. In a meta-analysis comparing the robotic versus the endoscopic techniques, there were no significant differences in operative time and conversions, [29] more complications and amount of drainage were recorded for robotic surgery, suggesting no clinical benefit for robotic thyroidectomy over multisite endoscopic thyroidectomy.

Complications related to the insufflation of the neck tissues, such as hypercapnia, respiratory acidosis, tachycardia, subcutaneous emphysema and air embolism, were documented, [28],[29],[30],[31] but can be possibly be prevented using CO 2 pressures between 6 and 8 mmHg. To avoid these complications, a gasless concept was also proposed by some authors. [20],[31],[32],[33] The robotic application still has to be studied regarding its safety and cost-effectiveness.

In our technique, we used a disposable port (Olympus Triport) that had never been used before, which enables more freedom using a smaller incision (2.0 cm in cadavers). The use of this special port for thyroidectomy was not previously described in the literature, and it allowed, in our experience, an adequate exposition and performance of the procedures with minimal collisions and difficulty. In transaxillary single-port thyroidectomy, it is possible to hide the scar in the axillar fossa and augment, if necessary, the incision to retrieve the specimen, still giving a good cosmetic result. This technique needs a team with some experience in single-port surgery for other indications because the working space is restricted and the instruments work in parallel causing some collision with the camera. Despite this, it was considerably simple to search, dissect and identify important anatomical structures such as laryngeal recurrent nerve and parathyroid glands. A 5 mm scope was useful to minimise the clash of the instruments. As reported by others, [26] the position of the camera and instruments allows creating two imaginary planes, upper plane for the scope and lower plane for the instruments. Another important point noted is the use of instruments of different lengths to avoid collision of one hand of the operator with another. In case of lack of exposition or difficult visualisation, more percutaneous suturing retraction or wires can be inserted to guarantee a safer procedure. In our opinion, is not necessary to use articulated or curved instruments with this specific port because of adequate exposition and performance of the procedures with minimal collisions, although it is possible.

A good aspect of the surgical procedure is the position of the patient. The technique does not require a hyperextension of the head, what may cause postoperative discomfort and pain. The platysma and prethyroid muscles are preserved in comparison to the open access, potentially resulting in less muscular damage and pain. An advantage of the technique is that it is not necessary to dissect to contralateral side of the lesion, leaving it intact for any future intervention at that side.

Although open surgery is currently the standard technique for thyroidectomy, minimally invasive techniques have the goals of diminishing visible scars and reducing cervical discomfort. The present study showed the anatomical and technical feasibility of single-site unilateral transaxillary thyroidectomy and parathyroidectomy. Further larger clinical studies still are needed to understand the indications of this new method as an alternative procedure for thyroid and parathyroid surgery.


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