Changing paradigms in endoscopic thyroid surgery: A comparison between scarless-in-the-neck axillo-breast approach and totally scarless transoral approach.

BACKGROUND: To avoid cervical scar in thyroid surgery, various approaches have been proposed. The commonly used approach is combined axillo-breast approach (ABA). However, trans-orovestibular approach (TOVA) is getting popular. The aim of this study is to compare surgical outcomes of patients who underwent endoscopic hemithyroidectomy (EHT) by either ABA or TOVA. PATIENTS AND METHODS: This was a retrospective analysis of clinical data of patients who underwent EHT from January 2013 to December 2018. Patients were divided into two groups: Group A - through ABA and Group B - through TOVA.
RESULTS: A total of eighty patients underwent EHT in Group A and 25 in Group B. In both groups, most patients were female (male: female = 1:4.7 in Group A and 1:7.33 in Group B, P = 0.515). In both groups, there was no difference in age (the mean age was 33.44 ± 10.44 years in Group A and 33.04 ± 14.01 years in Group B, P = 0.391) and in size of the nodule (Group A - 3.91 ± 1.17 cm and Group B - 3.6 ± 1.39 cm, P = 0.228). The operating time was significantly less in Group B (Group A - 152.25 ± 30.19 mins and Group B - 126.80 ± 22.94 mins, P ≤ 0.01). The post-operative hospital stay was significantly less in Group B (mean 3.17 ± 0.97 days in Group A and 2.24 ± 0.60 days in Group B, P ≤ 0.01).
CONCLUSION: TOVA is associated with shorter operating time and hospital stay with comparable outcomes. Cosmetic outcome is excellent in TOVA, however requires further subjective evaluation.

INTRODUCTION

In today’s era of cosmesis, patients used to demand scar-free neck surgery for thyroid disorder. It pushes surgeons to practice a variety of endoscopic surgical procedures for thyroid surgery, however surgeries for thyroid disorders usually require lots of efforts and laparoscopic surgical skills.

Since the inception of endoscopic thyroid surgery, different remote access approaches to the thyroid gland have been evolved.[1234] Out of these approaches, axillo-breast approach (ABA) is the most favourable approach for most surgeons. Natural orifice transluminal endoscopic surgery through oral route is the latest addition to the armamentarium.[5] After the initial reports of sublingual and transtracheal approaches, these approaches were abandoned due to a high incidence of recurrent laryngeal nerve (RLN) injury and conversion to open surgery. Trans-orovestibular approach (TOVA) has been popularised by Anuwong et al. with technical modifications.[6]

Endoscopic thyroid procedures have stood the test of time and proven to provide almost equivalent results as of open thyroid surgery for both benign and malignant thyroid disorders in selected group of patients.[7891011]

TOVA provides total scar-free surgery, whereas other endoscopic thyroidectomy (ET) procedures leave minimal scar at remote sites. As the demand of ET has been increasing, the onus is on the surgeon’s shoulder to choose the appropriate approach, which is feasible, is reproducible and gives good cosmesis without compromising safety of patients.

In the present study, we compare the surgical outcomes of patients who underwent endoscopic hemithyroidectomy (EHT) through ABA and EHT through TOVA.

PATIENTS AND METHODS

This is a retrospective analysis of patients who underwent EHT at a single, tertiary care centre from January 2013 to December 2018. Patients who underwent EHT were divided into the following two groups: Group A – through ABA and Group B – through TOVA. In Group A, EHT through ipsilateral axillo-breast approach (IAB approach) and bilateral axillo-breast approach (BAB approach) was performed. Patients with a minimum of 6-month follow-up were included in both groups. All endoscopic procedures were performed by a single surgeon. Technical details of the surgical procedures have been described in our previous publications.[1213] In the present study, we have compared the clinicopathological profile and surgical outcomes between both the groups. Pre-operative parameters included age, gender, thyroid function status, duration of symptoms, laterality, nodule size and cytological diagnosis. The peri-operative and post-operative parameters included ex vivo weight of the gland, bleeding or seroma formation, RLN injury, duration of surgery, duration of drain, hospital stay and final histopathological diagnosis.

Data analysis was done by Statistical Package for Social Sciences version 20.0 (IBM SPSS Statistic for Windows, Version 20.0. IBM Corp., Armonk, NY, USA). t-test was used for parametric data and the Mann–Whitney test was used for non-parametric data. P < 0.05 was considered statistically significant.

RESULTS

A total of eighty patients underwent EHT through ABA (Group A) and 25 through TOVA (Group B). Patients’ demography is described in Table 1. In Group A, 36 patients underwent EHT through IAB approach and 44 through BAB approach. Age was not significantly different between both groups (mean age was 33.44 ± 10.44 years in Group A and 33.04 ± 14.01 years in Group B, P = 0.391). In both groups, majority of the patients were female (male: female = 1:4.7 in Group A and 1:7.33 in Group B, P = 0.515). Most thyroid nodules were on the right side in both groups (Group A – 50 right, 29 left and 1 isthmic; Group B – 17 right and 8 left). The mean duration of symptoms was 30.99 ± 41.39 months in Group A and 24 ± 70.55 months in Group B (P = 0.027). In both the groups, the predominant pre-operative diagnosis was colloid goitre (64 in Group A and 20 in Group B). Fifteen patients in Group A and five patients in Group B had Bethesda III/IV diagnosis. There was no difference in the mean size of the nodule in both groups (Group A – 3.91 ± 1.17 cm and Group B – 3.60 ± 1.39 cm, P = 0.228).

Table 1

Patients’ demography

Parameters	ABA (n=80)	TOVA (n=25)	P
Age (years), mean	33.44±10.44	33.04±14.01	0.391
Male:female	14:66 (1:4.77)	3:22 (1:7.33)	0.515
Laterality
Right	50	17	0.779
Left	29	8
Isthmic	1	0
Approach
IAB approach	36	-	-
BAB approach	44	-
FNAC
Bethesda I	1	-	0.552
Bethesda II	64	21
Bethesda III	6	3
Bethesda IV	9	1
Bethesda V	-	-
Bethesda VI	-	-
Nodule size (cm), mean	3.91±1.17	3.6±1.39	0.228
Thyroid status
Euthyroid	68	23	0.497
Hypothyroidism	5	0
Hyperthyroidism	7	2
Duration of symptoms (months)	30.99±41.39	24±70.55	0.027

ABA: Axillo-breast approach, TOVA: Trans-orovestibular approach, IAB: Ipsilateral axillo-breast, BAB: Bilateral axillo-breast, FNAC: Fine-needle aspiration cytology

The surgical outcomes are described in Table 2. Ex vivo weight of the thyroid lobe was significantly less in Group B (mean weight: 26.18 ± 19.41 g in Group A and 11.96 ± 4.22 g in Group B, P ≤ 0.01). The operating time was significantly less in Group B (152.25 ± 30.19 mins in Group A and 126.80 ± 22.94 mins in Group B, P ≤ 0.01) The mean duration of drainage in Group A was 3.34 ± 1.01 days, whereas no drain was put in Group B. The post-operative hospital stay was significantly less in Group B (mean 3.44 ± 0.98 days in Group A and 2.24 ± 0.60 days in Group B, P ≤ 0.01).

Table 2

Perioperative outcomes

Parameters	ABA (n=80), n (%)	TOVA (n=25), n (%)	P
Conversion	4 (5)	-
Weight (g), mean	26.18±19.41	11.96±4.22	<0.01
RLN injury	1 (1.25)	-	<0.01
Drainage (days), mean	3.34±1.01	NA
Bleeding/haematoma	3 (3.75)	None	<0.01
Seroma	5 (6.25)	2 (8)	0.62
Skin bruising	-	-
Paraesthesia	8 (10)	1 (4)	<0.01
Permanent voice change	-	-
Tracheal/oesophageal injury	-	-
Chyle leak	-	-
Mental nerve injury	NA	-
Hospital stay (days)	3.44±0.98	2.24±0.60	<0.01
Operating time (mins), mean	152.25±30.19	126.8±22.94	<0.01

ABA: Axillo-breast approach, TOVA: Trans-orovestibular approach, NA: Not applicable, RLN: Recurrent laryngeal nerve

Five (6.25%) patients in Group A and two (8%) in Group B had seroma formation, which subsided with one-time aspiration (P = 0.62). Most patients in Group A had some degree of paraesthesia which rarely persisted beyond 3–6 months (n = 8, 10%), whereas only one (4%) patient in Group B complained of submental and neck paraesthesia which resolved in 3 months (P ≤ 0.01).

The final histopathological diagnoses are described in Table 3.

Table 3

Final histopathology

Histopathology	ABA	TOVA
Colloid nodule	50	19
LT	2	-
FN	18	4
HCN	3	1
PTC	1	-
FVPTC	3	-
MIFC	3	-
Granulomatous thyroiditis	-	1

ABA: Axillo-breast approach, TOVA: Trans-orovestibular approach, LT: Lymphocytic thyroiditis, FN: Follicular neoplasm, HCN: Hurthle cell neoplasm, PTC: Papillary thyroid carcinoma, FVPTC: Follicular-variant of PTC, MIFC: Minimally invasive follicular carcinoma

DISCUSSION

TOVA is the shortest, median central approach to provide equal access to both lobes of thyroid gland. Compared to ABA, it is less invasive, causes less flap dissection and has shorter route. The main advantage of TOVA is that it results in complete avoidance of visible scar, whereas other endoscopic thyroid procedures leave at least minimal scar away from the neck. Both procedures are feasible with conventional endoscopic instruments, which adds to cost-effectiveness, an important issue in this part of the world. Besides all the technicalities of endoscopic procedures, the foremost is that the straightforwardness of the surgeon and his/her unbiased selection of the most appropriate procedure to his/her patient. Moreover, the decision-making must be mainly based on the existing evidence of safety and results. For an endoscopic-endocrine surgeon, the first and foremost question that arises in mind is that is it safe to choose oral cavity over other remote sites just to avoid a hidden scar?

To the best of our knowledge, this is the first study to compare the clinicopathological and surgical outcomes of EHT using ABA and TOVA.

We had started performing endoscopic thyroid surgeries since 2013. Initially, our approach was IAB approach for EHT. Through experience, we have also started performing endoscopic total thyroidectomy (ETT). After adequate training, we adopted BAB approach for EHT as well as for ETT. We found that the BAB approach was ergonomically very suitable for ET; the steps were similar to the conventional open thyroid surgery and central approach to avoid shifting of ports for each lobe. After gaining further training and considerable experience of ET, we had started performing TOVA since 2016.

In both groups, the patients were younger (mean age was 33.44 ± 10.44 years in Group A and 33.04 ± 14.01 years in Group B, P = 0.391). This is a reflection of preference for scarless surgery chosen among the younger patients. The mean nodule size was comparable in both groups (mean size was 3.91 ± 1.17 cm in Group A and 3.6 ± 1.39 cm in Group B, P = 0.228) (range 1–7 cm in Group A and 2–7 cm in Group B).

ET was offered to patients with a cytological diagnosis of Bethesda I–IV in both the groups. Both the patient’s and surgeon’s choice affect the patient’s decision for ET. Patients’ fear for completeness of surgery for their malignant nodule and surgeon’s apprehension about timely and regular follow-up of the patient in the post-operative period are the main determining factors. This is particularly true for patients who are from a rural background and who have to travel long distance for follow-up. However, safety, feasibility and comparable outcomes of ET have been reported for malignant thyroid lesions.[91014]

The obvious advantage of TOVA is avoidance of drain for small-sized thyroid tumours. An additional axillary port may be used for specimen retrieval for larger tumours, which can be used later for tube drainage. ABA usually requires prolonged drainage than that of conventional open thyroidectomy.[78] This is due to more invasiveness and larger area of flap dissection. Our interpretation is that this may be a main contributory factor for the significantly shorter hospital stay in Group B (mean 3.44 ± 0.98 days in Group A and 2.24 ± 0.60 days in Group B, P ≤ 0.01). Patients without drain are generally discharged on the next day, however patients with drain are usually discharged only after the removal of drain.

The duration of surgery was significantly shorter in Group B (mean 152.25 ± 30.19 mins in Group A and 126.8 ± 22.94 mins in Group B, P ≤ 0.01). Various contributory factors may be associated with shorter operating time including shorter route, lesser dissection and median central view. Here, we want to emphasise that by the time the author had started TOVA, his learning curve for ABA had been over and had considerable experience of ET. In literature, it has been reported that 25 cases are required for learning curve in ABA, whereas 11 are required for TOVA.[1516]

The most common final histopathology was colloid nodule in both the groups [Table 3]. One patient in Group A who had the final diagnosis of papillary thyroid carcinoma (PTC) underwent completion thyroidectomy. Patients with follicular-variant PTC and minimally invasive follicular carcinoma are under observation.

Both techniques (ABA and TOVA) have been compared to conventional open thyroidectomies. A meta-analysis which compared ETT with the conventional open thyroidectomy in thyroid cancer concluded that there was no difference in peri-operative complications, whereas ET was associated with longer operating time, drainage and hospital stay.[17] In a comparative study of TOVA with open thyroidectomies, Anuwong et al. found no difference in operating time, blood loss and other perioperative outcomes, however the mean visual analogue scale score for pain was lower in TOVA group (1.1 [1.2] vs. 2.8 [1.2], P = 2.52 × 10−38).[11]

In our series of ET, TOVA has been associated with shorter operating time and hospital stay. The perioperative outcomes were comparable in both groups. Apart from these, the cosmetic outcomes were excellent in Group B patients. Primarily, there was no visible scar in TOVA, which gives psychological benefits to the patients. Second, less area of flap dissection and shorter route were associated with less disabling paraesthesia. Finally, technical modification as proposed by Anuwong et al. (insertion of lateral ports just lateral to the canine teeth) results in less incidence of mental nerve injury. However, further subjective evaluation of the quality of life after both procedures is required.

CONCLUSION

TOVA is associated with shorter operating time and hospital stay with comparable outcomes. Selection of appropriate patients and surgeon’s experience are the main contributing factors. Cosmetic outcome is excellent in TOVA, however requires further subjective evaluation.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.