Endoscopic thyroidectomy: Which one is the better technique for the beginners?

INTRODUCTION: Endoscopic thyroidectomy is an advanced procedure and has a long learning curve. Most commonly employed approach is combined axillary-breast approach (ABA). Recently, transoral endoscopic thyroidectomy vestibular approach (TOETVA) is being popularised as a scarless procedure. However, it is not established whether TOETVA or ABA approach is better to begin with.
PURPOSE: The purpose of the study was to compare the initial experience of TOETVA and ABA with respect to difficulties and outcomes.
METHODOLOGY: A prospective non-randomised interventional study was conducted including the initial ten patients in each group who underwent hemithyroidectomy for benign solitary thyroid nodule. Sigma plot version 12.3 was used for the statistical analysis.
RESULTS: All the patients were female and comparable with respect to age (33.2 vs. 28.2 years) and size of nodule (2.7 vs. 3 cm) (TOETVA vs. ABA). The operative time (121 vs. 138.5 min, P = 0.34) and blood loss (50 vs. 60 ml, P = 0.9) were similar in both the groups. Even though the flap raising time was significantly less with TOETVA group (29.3 vs. 47.2 min, P < 0.001), it was associated with more difficulty in approaching upper pole (P = 0.02) and lower pole (P < 0.001), more intra-operative events (30% vs. 10%, P = 0.58) and conversions to open (20% vs. 10%, P = 1). Similarly, post-operative pain scoring was more with TOETVA (3 vs. 2, P = 0.04). Hospital stay was similar in both the groups (2.5 vs. 3 days, P = 1). Patients in both the groups had both overall and cosmetic satisfaction.
CONCLUSIONS: Axillary-breast approach should be preferred to start learning the endoscopic thyroidectomy, as it is easier and safer than transoral endoscopic vestibular approach.

INTRODUCTION

Conventionally, the open thyroidectomy has been the gold standard ever since the era of Theodor Kocher.[1] Sometimes, patients, especially young females, do not want a visible scar in the neck and thus delay their surgeries. In today's era, minimally invasive or scarless surgeries are standard of care whenever feasible. Even though the first laparoscopic cholecystectomy was done by Erich in 1985,[2] it took another 12 years to perform the first endoscopic thyroidectomy in 1997 by Hüscher.[3] Miccoli et al. then demonstrated feasibility of minimally invasive video-assisted thyroidectomy in 1998.[4] Various endoscopic thyroidectomies have ever since been attempted with either axillary-breast approach (ABA),[56] transaxillary approach[78] and transoral endoscopic thyroidectomy vestibular approach (TOETVA) approach.[91011] However, endoscopic approach has not been widely utilised in developing countries because of non-availability, lack of training and long learning curve.[12]

METHODOLOGY

It was a prospective non-randomised interventional study of patients who underwent endoscopic hemi-thyroidectomy with either TOETVA or ABA at the department of Surgical Disciplines, All India Institute of Medical Sciences, New Delhi, India, from June 2016 to March 2018. All endoscopic thyroidectomies were performed by a single surgeon who had experience in endoscopic and laparoscopic surgeries other than thyroid surgeries. All patients who presented to the outpatient department with solitary thyroid nodules of <3 cm were enrolled. They underwent triple assessment including the physical examination, imaging and fine-needle aspiration cytology (FNAC) along with the thyroid function test. Finally, patients with a diagnosis of benign thyroid nodules were included in the study. Patients with evidence of malignancy or metastasis were excluded from the study. Patients were explained about the options of the endoscopic approach for thyroidectomy. Patients were also explained about the possible need to convert it into open procedure in case of intra-operative events. After patients gave informed written consent for the procedure, they underwent routine pre-anaesthetic checkup for fitness. Routine pre-operative indirect laryngoscopy was also performed to evaluate the baseline vocal cord mobility. Patients underwent hemi-thyroidectomy either with ABA or TOETVA. Nasal intubation was done for patients undergoing TOETVA. A total of 78 hemi-thyroidectomies were performed during this period. This included the first 20 endoscopic procedures that formed the study population and included 10 each with ABA or TOETVA. Others were open procedures done under general anaesthesia (n = 10) or under superficial cervical block (n = 48). Of the total 78 patients, only 10 were male and all of them underwent only open procedure.

Pre-operative variables included age, gender, ultrasound size and volume of the tumour and Bethesda grading of FNAC. Intra-operative details included total operative time, blood loss, flap raising time, difficulty level for surgeon during each procedure, conversions, intra-operative events and whether recurrent laryngeal nerve and parathyroid glands were identified or not. Post-operatively, immediate complications were noted along with pain status, patient's overall satisfaction and patient's cosmetic satisfaction confirmed with nursing staff's evaluation. Follow-up details included any long-term complications, histopathological details and any need for completion thyroidectomy.

Likert's scoring system was used for difficulty in the procedure (1–5; very easy, easy, not so difficult, difficult and very difficult), patient's overall satisfaction (1–5; strongly disagree, disagree, neutral, agree and strongly agree) and cosmetic satisfaction (1–5; very unhappy, unhappy, neutral, happy and very happy). Success of the procedure was defined as a score of ≥4. Pain status was assessed using the visual analogue scale (VAS; 0–10). Adequate pain control was defined as VAS score of ≤3.

Procedure

Three standard ports were used for both the techniques, and an additional port was used in ABA if required. Adequate flaps were raised and the midline opened in the case of TOETVA and lateral approach was taken for ABA [Figures 1 and 2]. Drains were routinely placed after the procedure. Patients were allowed oral sips after 4 hours, followed by clear liquids irrespective of type of the approach. Normal diet was allowed on the next day after surgery. Routine chlorhexidine mouthwash was advised for patients who underwent TOETVA, from the day of surgery. Patients were routinely followed up after 1 week of discharge from the hospital. Indirect laryngoscopy was repeated in symptomatic patients.

Figure 1

Transoral extravestibular approach (a) incisions for ports (b) two 5 mm and one central 10 mm ports placed (c) medial-to-lateral dissection (d) post-operative status

Figure 2

Axillary-breast approach (a) pre-operative marking for axillary-breast approach (b) One 10 mm peri areolar and two 5 mm axillary ports placed (c) lateral-to-medial dissection (d) post-operative status

Statistical analysis was carried out with Sigma plot v 12.3. Categorical variables were evaluated using Chi-square or Fisher's exact test. Continuous variables were evaluated using t-test (mean ± standard deviation) or Mann–Whitney Rank Sum Test (Median; 25th – 75th quartile). Statistical significance was kept at P < 0.05.

RESULTS

Pre-operative variables

Both the groups were comparable in terms of age (33.2 vs. 28.2 years) and gender (all females in both the groups) [Table 1]. Bethesda classification based on FNAC (all category II in both groups) and size of the tumor as measured by ultrasound were also comparable between the groups (2.7 vs. 3 cm, P = 0.32).

Table 1

Pre-operative variables

Variables	TOETVA (n=10)	ABA (n=10)	P
Age (years)	33.2±10.42	28.2±8	0.24
Gender
Female (%)	10 (100)	10 (100)	1
USG size (cm, one dimension) (n=9)	2.7 (2-3)	3 (2.25-3.9)	0.32
USG volume (n=9)	9.2±5.8	14.9±11.5	0.20
FNAC Bethesda category II (%)	10 (100)	10 (100)	1

FNAC: Fine-needle aspiration cytology, TOETVA: Transoral endoscopic thyroidectomy vestibular approach, ABA: Axillary-breast approach, USG: Ultrasound

Operative variables

All patients underwent endoscopic hemi-thyroidectomy for solitary thyroid nodule. Operative time was comparable in both the groups (121 vs. 138.5 min) and so was the operative blood loss (50 vs. 60 ml) (TOETVA vs. ABA) [Table 2]. The flap raising time was significantly less with TOETVA group (29.3 vs. 47.2 min, P < 0.001). However, the surgeon experienced more difficulty in approaching the upper pole and lower pole of thyroid in TOETVA with higher Likert scoring (4 vs. 2, P = 0.02 and 3.7 vs. 2 P < 0.001, respectively). Intra-operative events were more with TOETVA compared to ABA (30% vs. 10%, P = 0.58). It included intra-operative bleeding in TOETVA (10%) and subcutaneous emphysema (20% in TOETVA vs. 10% in ABA). Twenty percentage of conversions were present in TOETVA versus 10% in ABA (P = 1).

Table 2

Operative variables

Operative outcome	TOETVA (n=10)	ABA (n=10)	P
Operative time (min)	121±35.5	138.5±44.8	0.34
Flap raising time (min)	29.3±8.4	47.2±10.9	<0.001
RLN identified (%)	6 (60)	8 (80)	0.62
Parathyroid identified (%)	8 (80)	8 (80)	1
Approaching upper pole	4 (3-4.25)	2 (2-4)	0.02
Approaching lower pole	3.7±0.67	2±0.81	<0.001
Blood loss (ml)	50 (30-156.25)	60 (30-100)	0.9
Intra-operative events (%)	3 (30)	1 (10)	0.58
Intra-operative bleeding (%)	1 (10)	0	1
SC emphysema (%)	2 (20)	1 (10)	1
Conversion (%)	2 (20)	1 (10)	1

TOETVA: Transoral endoscopic thyroidectomy vestibular approach, ABA: Axillary-breast approach, RLN: Recurrent laryngeal nerve, SC: Subcutaneous

Post-operative outcomes

Patients in both the groups experienced almost similar post-operative complications in the form of transient voice change (10% vs. 20%), flap ecchymosis (0 vs. 10%), neck and face emphysema (20% vs. 10%), dysphagia (50% vs. 40%), flap paraesthesia (30% vs. 50%) and flap insensation (0 vs. 10%) in TEOTVA vs. ABA [Table 3]. Only one patient in ABA continues to have voice changes and is undergoing speech therapy. However, patients who underwent TOETVA experienced significantly more pain (3 vs. 2, P = 0.04) during the immediate post-operative period. Patients in TOETVA group stayed for a median duration of 2.5 days versus 3 days in the ABA group (P = 1). All patients reported overall and cosmetic satisfaction with Likert scoring of 4 versus 5 and 4 versus 4.5, respectively, with TOETVA versus ABA. Evaluation from nursing staff for cosmetic satisfaction revealed similar findings with Likert scoring of 5 versus 5. All patients in either group would recommend other patients for endoscopic procedure.

Table 3

Post-operative outcomes

Postoperative outcome	TOETVA (n=10)	ABA (n=10)	P
Postoperative complications (%)
Voice change	1 (10)	2 (20)	1
Flap ecchymosis	0	1 (10)	1
Neck and face emphysema	2 (20)	1 (10)	1
Dysphagia	5 (50)	4 (40)	1
Flap paraesthesia	3 (30)	5 (50)	0.65
Flap insensation	0	1 (10)	1
VAS score	3 (2-3.25)	2 (2-2.25)	0.04
Hospital stay (days)	2.5 (2-3.5)	3 (2-3)	1
Patient overall satisfaction	4 (4-5)	5 (4-5)	0.48
Patient cosmetic satisfaction	4 (4-5)	4.5 (4-5)	0.69
Nursing staff cosmetic evaluation	5 (4-5)	5 (4.7-5)	0.65
Patient referral for endoscopic procedure (%)	10 (100)	10 (100)	1

VAS: Visual analogue scale, TOETVA: Transoral endoscopic thyroidectomy vestibular approach, ABA: Axillary-breast approach, SC: Subcutaneous

Follow-up details

On histopathological examination, majority of the patients were found to have adenomatous goitre (60% vs. 40%), papillary thyroid microcarcinoma (20% vs. 0), follicular adenoma (0 vs. 40%), microinvasive follicular carcinoma (10% vs. 0), follicular variant of papillary thyroid carcinoma (PTC) (0 vs. 10%) and thyroiditis (10% in each group) as TOETVA versus ABA [Table 4]. Weight of the resected gland (7 vs. 9.25 g), size of the resected gland (7.4 vs. 12.23 cc) and size of the tumour (5.8 vs. 6 cc) were comparable in both the groups.

Table 4

Follow up outcomes

Postoperative outcome	TOETVA (n=10)	ABA (n=10)	P
HPE diagnosis (%)			-
Adenomatous goitre	6 (60)	4 (40)
PTC	2 (20)	0
Follicular variant PTC	0	1 (10)
Follicular adenoma	0	4 (40)
Follicular carcinoma	1 (10)	0
Thyroiditis	1 (10)	1 (10)
Weight of the resected gland (g)	7 (5-9) (n=7)	9.25 (8-13.75) (n=6)	0.073
Gland size (cc)	7.4±6.7 (n=9)	12.23±4.9	0.1
Tumour size (cc)	5.8±7.6 (n=4)	6±4.6 (n=5)	0.9

PTC: Papillary thyroid carcinoma, TOETVA: Transoral endoscopic thyroidectomy vestibular approach, ABA: Axillary-breast approach, HPE: Histopathological examination

Twenty percentage of patients in TOETVA had to undergo open completion thyroidectomy. One patient had follicular microcarcinoma, which on completion thyroidectomy was found to have no residual foci of malignancy. Another patient had follicular variant of PTC, who underwent completion thyroidectomy along with lymph node dissection. Histopathological examination revealed only adenomatous changes with lymph nodes free of tumour.

DISCUSSION

Endoscopic thyroidectomy has gained importance for having similar efficacy as open with better cosmetic results.[46713] In our study, all patients had excellent cosmetic results with either TOETVA or ABA. However, pain was severe with TOETVA compared to ABA. Moreover, surgeon experienced more difficulty with flap raising in TOETVA with limited dissecting planes. Operative time and blood loss were also similar with either approach. Similar findings were noted in patients who underwent endoscopic thyroidectomy via vestibular or areolar approach.[11] Longer operative time has been reported with endoscopic approach, however, with associated less post-operative pain compared to open approach.[13] It can be because of long learning curve for endoscopic thyroidectomy. A study with TOETVA has found learning curve of 7–10 patients for endocrine surgeons who routinely perform laparoscopic procedures.[13] Common causes for conversions were found to be bleeding and difficult plane dissection.[14] In our experience, two patients in TOETVA group (20%) had to be converted to open procedure because of intra-operative bleeding in one patient and dense adhesions in the other. Similarly, dense adhesion was the cause of conversion noted in a patient who underwent thyroidectomy through ABA (10%). Bleeding was also a common cause of conversion in a large study with 425 patients who underwent TOETVA.[13] Proper evaluation and selection of patient is, therefore, essential especially in the early period of learning. This strategy is supported by a study, where in the earlier period of learning curve, young female patients with tumour diameter <5 cm and weight <60 g were selected. The study documented only one conversion out of 1250 patients who underwent endoscopic thyroidectomy via areolar access.[15] Our patient distribution was similar in both the groups except that the thyroid gland removed by TOETVA tended to have lower weight (7 vs. 9.25 g). Incidence of transient hoarseness of voice among patients with TOETVA or ABA was similar in our patients. The incidence of recurrent laryngeal nerve palsy in literature after thyroidectomy has been reported to be up to 7.2% for transient and up to 5.2% for permanent palsy.[161718]

Transoral endoscopic vestibular access has the advantage of scarless skin and better cosmetics compared to areolar access.[19] In that sense, ABA approach cannot be considered truly minimally invasive, as it needs longer dissection plane.[9] Our results, however, have shown similar cosmetic satisfaction with either approach. Transoral vestibular approach also has the benefit of midline access which makes it easier for bilateral thyroidectomy and central neck dissection.[10] However, initially, on the learning curve, TOETVA might be difficult approach to start with as demonstrated by the present study.

Endoscopic procedure is feasible even for differentiated thyroid cancers[1020] and for completion thyroidectomy.[10] Endoscopic ABA has similar oncological outcome in terms of lymph nodes harvested, radioactive iodine uptake study and thyroglobulin levels for differentiated thyroid cancer who underwent total thyroidectomy and central lymph node dissection.[20] In the present study, however, two of ten patients under TOETVA underwent open completion thyroidectomy for follicular microcarcinoma and follicular variant of PTC. Utilising minimally invasive completion thyroidectomy would be another promising aspect.

Limitations

Small sample size is one of the limitations of the study. This questions its statistical significance and apparently higher percentage of the complications observed. Another aspect is the mixture of various procedures presented in the study that cannot be generalized to any individual procedure.

CONCLUSIONS

The study is an initial experience of endoscopic thyroidectomy in a tertiary care setting of a developing country. It highlighted the feasibility, challenges and outcomes of the transoral endoscopic thyroidectomy vestibular approach and axillary-breast approach. Axillary-breast approach is an easier and safer technique of endoscopic thyroidectomy for the beginners.

FUTURE DIRECTIONS

Our future studies will be focused on a larger study population with individual minimally invasive procedure and the comparison of its outcome with open thyroidectomies. Endeavors should also be taken to increase the implementation of the procedure.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.