Transoral endoscopic total thyroidectomy vestibular approach: A case series and literature review.

Conventional open thyroidectomy is often associated with post-operative complications including nerve damage, voice disturbances, paraesthesias, adhesions and prominent scarring. Several endoscopic surgical techniques have been reported as alternatives to conventional thyroidectomy. Natural orifice transluminal endoscopic surgery is a promising approach which leaves no scar, produces few complications and affords faster discharge from care. Several studies have explored its utility in total thyroidectomy in patients with benign or malignant thyroid disease. Herein, we present a case series on the successful application of transoral endoscopic total thyroidectomy vestibular approach (TOETVA) in benign and malignant diseases of the thyroid. We performed TOETVA in 11 patients presenting with benign or malignant thyroid nodules in our hospital, between 1st January 2015 and 30th June 2016. The surgery was completed successfully in all patients with a pre-operative diagnosis of multinodular goitre. The surgery was performed under general anaesthesia and the mean operative time was 130 min. The mean blood loss was 2-3 cc. No incidence of recurrent laryngeal nerve injury, damage to mental nerve, parathyroid damage or peri-incisional adhesion occurred in the study participants. No visible scarring occurred in the patients following surgery. The patients had an uneventful recovery after the surgery and were discharged after 4 days. TOETVA is safe and effective in the surgical management of multinodular goitre and offers a scar-free alternative to conventional surgery.

INTRODUCTION

Thyroid hypertrophy and nodules are a major cause of morbidity worldwide, and surgical management is often the mainstay of their treatment. The classical open thyroidectomy was pioneered by Theodor Kocher in 1898. It is the most common surgical procedure for thyroid disorders and usually involves an anterior cervical ‘necklace’ incision. Injury to recurrent laryngeal nerve and accidental removal of parathyroid glands can complicate classical thyroidectomy, and reports indicate their increasing occurrence. Hoarseness of voice, difficulty swallowing, paraesthesias during neck movement as well as peri-incisional adhesions might also develop after uneventful classical thyroidectomy.[12] A visible surgical scar in the exposed region of the neck may also cause psychological distress and self-image disturbances in the patients.[3]

There is a sustained interest in minimally invasive procedures for thyroidectomy which can avoid the surgical and cosmetic sequelae. About twenty techniques currently exist for thyroid surgery.[4] However, endoscopic surgery, especially through transaxillary and transthoracic approaches, is preferred at present. These techniques produce only minimal scarring. However, they still involve considerable dissection as natural anatomical planes to access the gland are scarce.

Natural orifice transluminal endoscopic surgery (NOTES) has gained considerable attention in surgical practice in recent years, as it can minimise surgical trauma, tissue damage and morbidity and promote a quicker recovery.[5]

The transoral approach provides a promising alternative to conventional thyroidectomy. The technique involves minimal dissection and preserves anatomic integrity, is truly scar-free, minimises post-operative morbidity and shortens the hospital stay. In the pioneering study, Anuwong[6] employed transoral endoscopic total thyroidectomy vestibular approach (TOETVA) for thyroid lobectomy in 42 and total thyroidectomy in 22 patients. Subsequently, Witzel et al.[7] evaluated the transoral approach for endoscopic thyroid resection in a porcine model and Benhidjeb et al.[8] in human cadaveric models. Following this, several authors have employed this technique in total thyroidectomy in patients with benign or malignant thyroid disease.[9101112] In this article, we discuss a case series of patients who underwent total thyroidectomy through this technique in our hospital.

Subjects

A total of 11 female patients who attended our hospital during the period from 1st January 2015 to 30th June 2016 were included in the study. The study was approved by the hospital's Institutional Ethics Committee. The inclusion criteria included a diagnosis of nodular thyroid disease, with a nodule size <40 mm and thyroid volume up to 30 mL. Patients with a history of conventional thyroid surgery, neck irradiation or thyroid sizes and volumes greater than mentioned earlier were excluded from the study.

Clinical and ultrasonographic examination suggested a diagnosis of benign multinodular goitre in all patients. All the patients were women and ranged in age from 19 to 33 years. Thyroid function test revealed hypothyroidism in nine patients, whereas one patient had hyperthyroidism and one was euthyroid. Ultrasonography was suggestive of multinodular goitre in all cases. Pre-operative fine needle aspiration cytology revealed papillary neoplasia in nine cases, follicular neoplasia in one patient and nodular goitre in one patient. Histological examination of tissue removed at surgery was suggestive of benign multinodular goitre in ten patients and papillary cancer of the thyroid (follicular variant) in one patient.

Preparation for surgery

The patients underwent dental scaling and were asked to gargle with chlorhexidine mouthwash twice a day for a week till surgery to reduce the oral microbial load and for prevention of post-operative infections.

Positioning

The patients were placed in supine position for the surgery, with a pillow placed below the shoulder and head ring to maintain neck extension (the chin and xiphisternum were maintained at the same plane). The chief surgeon remained at the head end of the table. The camera surgeon was on the left side of the chief surgeon and the second assistant occupied the right side of the surgeon. A monitor was placed on the table between the legs [Figure 1].

Figure 1

Position of surgeons and assistants during surgery. Surgeon stands at head end, camera surgeon stands left to the surgeon and second assistant stands right side to the surgeon

Surgery

All patients received general anaesthesia. Endotracheal intubation was done through nasal route. The oral cavity was cleaned with 0.9% normal saline. The gland was approached through the inferior vestibule of the oral cavity through which the midline 10 mm camera port was inserted. A 0° scope was introduced through the port and a space created by CO2 insufflation (as practiced in hernia surgery). CO2 insufflation was maintained at 6 mmHg. Two 5 mm working ports were introduced in front of the canine tooth on both sides, under endoscopic visualisation [Figure 2].

Figure 2

The patients were placed in supine position for the surgery, with the use of a pillow support below the shoulder and head ring to maintain neck extension

The subplatysmal plane was entered and dissected to create the working space. A harmonic scalpel and vessel sealers were used to cut the vessels. The deep fascia was opened in the midline, and the strap muscles retracted externally on either sides using 2–0 Ethilon. Subsequently, we identified and divided the isthmus of the thyroid, and then the superior and inferior pedicles on either side [Figure 3]. Middle thyroid vein, superior thyroid artery and vein were ligated close to the thyroid gland. Utilising the magnified view through the endoscope, the recurrent laryngeal nerve was identified easily and preserved on either side. All four parathyroid glands were identified and preserved. Complete haemostasis was secured. The entire lobe was brought out through the oral cavity using a custom-made endobag (ethylene oxide-sterilised Sambar bag), through the 10 mm port [Figure 4]. The specimen was cut into fine pieces and placed into the endobag, under the guidance of the 5 mm scope. A drain was placed using the 3 mm port into the lateral side of neck. Strap muscles were re-approximated, and the deep fascia closed in layers using absorbable sutures. The oral vestibular surgical wound was closed using absorbable sutures. A pressure dressing was applied over the chin and neck for 24 h. All patients resumed an oral diet on the first post-operative day, received three doses of intravenous cefazolin (1 g, every 8 h) and continued oral rinse with chlorhexidine solution.

Figure 3

Position of ports

Figure 4

Removal of the specimen using endobag

RESULTS

The operative time, blood loss during surgery, intraoperative drain insertion, post-operative complications, duration of hospital stay and cosmetic results were monitored and recorded. Tables 1 and 2 summarise the clinical data of the participants.

Table 1

Clinical summary of the patients

Table 2

Mean operative blood loss in the patients

DISCUSSION

Direct (cervical – anterior or lateral), extracervical as well as combination approaches exist for thyroidectomy.[13141516] Endoscopic thyroidectomy is currently preferred in the treatment of symptomatic benign thyroid nodules, follicular tumours and Grave's disease.[17] A number of endoscopic approaches have been successfully employed for thyroidectomy including axillary,[18] submandibular,[19] breast,[20] bilateral axillo-breast approach[21] and transoral.[10112223] Lv et al.[3] recently reported results from a randomised clinical trial on 44 patients, comparing conventional thyroidectomy with a novel bilateral supraclavicular approach. The authors observed a slight increase in total incision length in the bilateral supraclavicular group, but a significantly shorter period of post-operative symptoms and lower risk for adhesion formation in the supraclavicular group.

Pisanu et al.[24] in their recent article systematically reviewed nine prospective randomised controlled studies comparing minimally invasive video-assisted thyroidectomy (MIVAT) to conventional thyroidectomy. The authors noted a higher operative time but lesser incidence of post-operative pain and better patient satisfactory scores in the MIVAT group.

Complete avoidance of post-operative scarring remains a distinct advantage of NOTES, and hence the technique has been explored in thyroidectomy. With meticulous technique and surgical skills, achieving minimal operative blood loss is feasible though careful choice of patients would also be important to this end.

The NOTES approach was pioneered in thyroid surgery in human patients by Wilhelm and Metzig,[9] who named their technique endoscopic minimally invasive thyroidectomy (eMIT). The authors performed successful thyroidectomy in eight patients through incisions made in the floor of the mouth. Nakajo et al.[10] reported the utility of a gasless, transoral video-assisted neck surgery (TOVANS) procedure for thyroidectomy in eight patients employing a pre-mandible approach and anterior neck-skin lifting. Wang et al.[11] reported a study comparing transareolar approach and endoscopic thyroidectomy oral vestibular approach (ETOVA).

The present study employed a TOETVA on 11 consecutive patients who presented to our hospital with a diagnosis of multinodular goitre. The post-operative histologic diagnosis generally agreed with the pre-operative imaging and laboratory diagnosis, except in one patient in whom the multinodular disease turned out to be papillary carcinoma of the thyroid.

In the present study, the total operative time was 130 min, which was comparable to that reported by Anuwong (2016)[6] in a similar study and lesser than eMIT and TOVANS reported earlier. Pai et al.[25] recently reported on a successful endoscopic hemithyroidectomy in a 21-year-old female patient, with a mean operative time of 2 h.

The mean blood loss in the present series was only 2–3 cc, which was significantly lesser than that reported in previous studies employing TOVANS, ETOVA or TOETVA. None of the patients required intraoperative conversion to open surgery.

Accidental removal of parathyroid glands remains a significant risk following thyroidectomy. Anuwong (2016)[6] recently reported hypoparathyroidism in 5% of the patients who underwent TOETVA. None of the patients in the present study developed this complication in the post-operative period.

Injury to recurrent laryngeal nerve is another potential complication after thyroid surgery. None of the patients who underwent surgery in the present series developed transient or long-lasting damage to the recurrent laryngeal nerve. No incidence of mental nerve palsy also occurred in the study cohort. These are in agreement with the earlier reports on endoscopic thyroid surgery.

The wound in transoral endoscopic total thyroidectomy is considered as a Type II (clean-contaminated) wound, warranting antibiotic prophylaxis against Gram-positive and anaerobic bacteria.[10] All patients in the present series received three doses of intravenous cefazolin and none developed a post-operative infection.

Wound infection, mediastinal emphysema, sensory disturbances and ecchymosis around the skin and late ecchymosis have been reported following eMIT. Transient surgical emphysema was reported by Pai et al.[25] in a patient who underwent transoral endoscopic hemithyroidectomy. However, no such events occurred during the post-operative period amongst the patients in the present study. No incidence of peri-incisional adhesions was observed in the patients who underwent surgery. No patient required the placement of a drain or developed sensory abnormalities involving the cervical skin after the surgery.

We also analysed the drawbacks of the present study. Bias could not be eliminated completely, as no blinding method was employed. The small sample size may affect the generalizability of the results obtained, which could have been improved with a larger number of participants. The long operative time remains another attribute that needs to be improved. The surgeons’ experience and skills would be critical to obtain the best possible cosmetic outcome and might involve a prolonged learning curve.

Overall, the present series revealed the utility of the transoral approach for patients with nodular disease of the thyroid with a benign or malignant aetiology.

CONCLUSION

TOETVA is a safe and practical technique for the surgical management of benign and malignant nodular disease of the thyroid. It minimised intraoperative blood loss and post-operative complications and yielded excellent cosmetic results. Its utility needs to be evaluated further in randomised controlled clinical trials employing a larger number of patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.