Transoral endoscopic neck surgery: feasibility and safety in a porcine model based on the example of thymectomy

OUP accepted manuscript

BACKGROUND

The IDEAL Framework is a scheme for safe implementation and assessment of surgical innovation. The transoral endoscopic thyroidectomy vestibular approach (TOETVA) is a new innovation in thyroid surgery that eliminates the need for a cervical incision. Despite considerable interest and adoption worldwide, significant scepticism remains regarding the outcomes and cost-effectiveness for healthcare systems. The aim of this narrative review was to appraise the available literature and examine whether TOETVA has progressed in line with the IDEAL Framework.

METHODS

A literature review of PubMed with a focus on historical and landmark studies was undertaken to classify the evidence according to the different stages of the IDEAL Framework.

RESULTS

Several different transoral approaches were developed by a small of number of surgeon-innovators on animals and cadavers, and subsequently in first-in-human studies. The trivestibular approach emerged as the safest technique, with further refinements of this technique culminating in TOETVA. The basic steps and indications for this technique have been standardized and it is now being replicated by early adopters in many centres worldwide. The development of TOETVA has closely aligned with the IDEAL Framework, and is currently at stage 2B (Exploration).

CONCLUSION

There is need for multi-institutional collaborations and international registry studies to plan high-quality randomized trials comparing TOETVA with other remote-access approaches and collect long-term follow-up data. In countries where TOETVA has yet to be adopted, the IDEAL Framework will be a useful roadmap for government regulators and professional societies to evaluate, regulate, and provide best practice recommendations for the adoption of this technique.

Noninvasive thyroid histotripsy treatment: proof of concept study in a porcine model

INTRODUCTION

This study was performed to determine the feasibility and safety of creating superficial histotripsy treatment in a live porcine thyroid model.

METHODS

The porcine thymus comparable in size, shape and location to the human thyroid was used for this study. This model has been used for thyroid surgery studies due to the diminutive size of the porcine thyroid. Four female swine underwent a total of eight histotripsy treatments performed with a prototype therapy system (HistoSonics, Inc., Ann Arbor, MI). Two treatments were performed in each animal: a spherical 1.0 × 1.0 × 1.0 cm and ovoid 1.0 × 1.0 × 2.0 cm treatment zones. MRI immediately post-procedure was evaluated for histotripsy treatment zone size and imaging appearance, followed immediately by sacrifice. Tissue was then reviewed for percent cellular destruction and precision.

RESULTS

Treatment zones measured on post treatment MRI were similar to prescribed volumes (spherical = 0.60 (+/- 0.11) cm³, ovoid = 1.23 (+/- 0.40) cm³, p > 0.05 vs. prescribed). MRI demonstrated well demarcated treatment zones and imaging findings consistent with cellular destruction. Histology demonstrated sharp transitions to normal tissue (mean 0.33 (+/- 0.13) cm), and high degrees of cellular destruction (mean 76% (+/- 12.5), range of 50-100%) in the treated tissue. Edema within the overlying muscle was seen in 2/8 treatments.

CONCLUSION

Histotripsy is capable of safely creating precise histotripsy treatments within the superficial neck of a porcine thyroid model without evidence of considerable complications.

Trans oral endoscopic thyroidectomy (TOETVA): First French experience in 90 patients

OBJECTIVE

Thyroidectomy techniques using extracervical approaches have grown in popularity for about 20 years and their feasibility has now been demonstrated. We wanted to evaluate one of these new approaches: the anterior vestibular endoscopic approach (TOETVA). The aim of this study was to evaluate the results of an initial series patients who underwent an anterior trans-vestibular endoscopic oral thyroidectomy.

METHODS

From February 2018 to September 2020, this technique was offered to patients aged 18 to 70, ASA I or II, who presented with an indication for thyroid surgery and who wished to avoid cervical scars. The approach was through the anterior vestibule of the mouth and the specimen was extracted either transorally or via the axilla depending on its size. Apart from the first ten cases, all patients underwent recurrent nerve neuromonitoring. The patients were operated on by two surgeons experienced in thyroid surgery. All the patients had follow-up visits on D15, D30 and at 2 months. The pre- and intra-operative data, length of stay and complications were evaluated.

RESULTS

A total of 90 consecutive patients (87 women) aged 46±12.4 years (18 to 69) with a mean BMI of 24.4±4 were included. The indications for surgery included 11 papillary cancers, 5 oncocytic nodules, 15 toxic nodules, 13 cases of Graves disease and 46 symptomatic goiters and/or nodules. The mean pre-operative diameter of the nodules was 3.61±1.99 (0.44 to 7.3) cm. The interventions performed were 44 lobo-isthmectomies, 41 total thyroidectomies and 5 isthmectomies. The mean operating time was 134±45min (40 to 255). On D1, the post-operative ionized calcium was 1.09±0.11mmol/L (4.3685±0.44mg/dL) (normal 0.8-1.15mmol/L) (3.206-4.609mg/dL)) and the total serum calcium was 2.07±0.11mmol/L 8.296±0.44mg/dL (normal 2.2-2.5mmol/L) (8.817-10.019mg/dL). Five patients underwent conversion from endoscopic to open cervical approach (5.5%). The complications were seven cases of transient recurrent nerve palsy (7.8%), eight cases of hypoparathyroidism (19%) including six transient and two permanent, one skin burn and 26 cases of transient chin numbness related to the electrocautery (29%). Ten patients (11%) presented with transient post-operative skin ecchymosis that resolved within 7-10 days. A spontaneous pneumo-mediastinum was observed on chest CT in three patients and evolved favorably. No hematoma, or surgical site infection, or complications related to axillary extraction were observed. All the patients declared themselves satisfied post-operatively and at the end of the follow-up.

CONCLUSION

The TOETVA route of entry is a safe and reliable technique in well-selected patients wishing to avoid a cervical scar.

Hybrid techniques and patients' safety in implementing transoral sublingual thyroidectomy

PURPOSE

Cosmetic advantages and minimally invasive aspects become more and more important for patients undergoing thyroidectomy. We report on our personal experience and conceptual design in dealing with approaches to the thyroid gland, which we were the first to describe. We report on ideas and experiences concerning its implementation.

METHODS

Our own experiences and considerations in the process of finding an endoscopic minimally invasive access in thyroidectomy are compared in a systematic review with the available literature on minimally invasive or endoscopic thyroid surgery. We describe our failures and risk assessment.

RESULTS

Our analysis of the literature on minimally invasive thyroidectomy and our own experiences lead us to the conclusion that using different hybrid technologies during the implementation of endoscopic procedures in thyroid surgery can be helpful and could improve patients' safety. A combination of transoral endoscopic and non-transoral techniques might be a useful safer, but more traumatizing alternative for implementation. Several studies show the feasibility of the transoral access in thyroid surgery. We believe that the implementation of these new procedures as routine surgery in specialized centers must be carefully considered and discussed.

CONCLUSIONS

The transoral access seems to be less invasive than other extracollar endoscopic accesses in thyroid surgery. For a sublingual single-access routine surgery, better instruments are needed. The vestibular access is possible with standard instruments. Using hybrid technologies for implementation should not be considered as a failure. The transoral thyroidectomy can be a safe method in the hand of experienced surgeons. We expect this hybrid technique to play a major part in further spreading endoscopic transoral thyroid surgery.

Transoral endoscopic mediastinal surgery (TOEMS)-results of a first clinical study for scarless mediastinal lymph node biopsies

BACKGROUND

Video-assisted mediastinoscopy (VAM) represents the standard procedure for mediastinal lymph node biopsies. This operation results in a scar at prominent position at the anterior neck. Since there is a trend to less invasive procedures, natural orifice transluminal endoscopic surgery (NOTES) was introduced to different fields of surgery. Based on NOTES we developed a new approach for mediastinoscopy: transoral endoscopic mediastinal surgery (TOEMS). In previous studies using human cadavers and living pigs the feasibility of TOEMS was shown. It was unclear whether TOEMS could be safely applied in patients requiring mediastinal lymph node biopsies.

METHODS

We conducted a clinical phase I study recruiting ten patients with unclear mediastinal lymphadenopathy not resolved by prior bronchoscopy. All patients underwent TOEMS for mediastinal lymph node biopsy. The duration of the procedure and complications were monitored. In addition, all patients were examined for pain, swallowing dysfunction and sensation disturbance.

RESULTS

TOEMS was accomplished in eight patients. In two patients operation was converted to VAM due to technical problems. Mediastinal lymph nodes were dissected in all patients who finished with TOEMS. On average, two separate lymph stations were reached by TOEMS. Duration of the procedure was 159±22 min. Permanent palsy of the right recurrent laryngeal nerve was noticed in one patient postoperatively.

CONCLUSIONS

This is the first report for a human application of NOTES in thoracic surgery. In fact, transoral endoscopic surgery seems to be a feasible approach for mediastinal lymph node biopsies. Further studies are needed to show whether this procedure has an advantage over VAM in terms of pain, complications and accessibility of mediastinal lymph node stations.

Natural Orifice Total Transtracheal Endoscopic Thyroidectomy Surgery: First Reported Experiment

BACKGROUND

Natural orifice translumenal endoscopic surgery (NOTES(®); American Society for Gastrointestinal Endoscopy [Oak Brook, IL] and Society of American Gastrointestinal and Endoscopic Surgeons [Los Angeles, CA]) is an improvement in surgical interventions. In this study we developed an innovative transtracheal endoscopic thyroidectomy technique and explored its feasibility in animal models.

MATERIALS AND METHODS

Transtracheal endoscopic thyroidectomy was performed in anesthetized dogs and pigs. The endoscope was advanced into the pretracheal space via a longitudinal incision on the anterior tracheal wall. Hemithyroidectomies and partial lobectomy were performed using special double-lumen endotracheal tubes and conventional endoscopic instruments. The tracheal wall incision was closed using absorbable sutures, and the animals were sacrificed at Day 5 postsurgery.

RESULTS

Hemithyroidectomy and partial thyroidectomy were successfully performed on pigs and dogs. The average operative time for each model was 69.4 minutes. No significant complications were encountered during surgery.

CONCLUSIONS

The transtracheal endoscopic thyroidectomy technique is feasible and has the potential to be an alternative method for other types of thyroid surgeries.

Anatomical study of surgical approaches for minimally invasive transoral thyroidectomy: eMIT and TOPP

OBJECTIVE

Anatomical study of surgical approaches of endoscopic minimally invasive thyroidectomy (eMIT) and transoral partial parathyroidectomy (TOPP) was conducted to evaluate their safety and feasibility.

MATERIAL AND METHODS

After performing an eMIT- and TOPP-procedure on fresh frozen human cadavers, a layer-by-layer dissection of the floor of the mouth and the anterior cervical region was carried out in five specimens. The blood vessels, nerves and muscles related to the surgical approach were exposed.

RESULTS

The anterior region of the neck can be reached through the midline of the mouth floor and the suprahyoid muscles. No important nerves and vessels were found in the approach of eMIT. TOPP set up the space at the dorsal side of the thyroid gland and adjacent to the trachea. The hypoglossal nerve and the lingual nerve as well as their accompanying blood vessels were anatomically related to the approach and could be injured during the procedure. The surgical space is much limited in TOPP (<20 mm in diameter) and current surgical instruments still did not match the requirement of this technique.

CONCLUSIONS

This study demonstrated that the transoral approach of eMIT is anatomically safer and more feasible than that of TOPP.

The safety of transoral periosteal thyroidectomy: results of Swine models

BACKGROUND

Endoscopic thyroid surgery is gaining wide acceptance; however, existing endoscopic methods for thyroidectomy have shown several limitations. Recently, a transoral technique using video assistance and endoscopy has been reported for thyroidectomy. The aim of this study was to define a new technique of transoral thyroidectomy using a mandibular periosteal approach to complement other types of natural orifice surgery and minimally invasive surgery.

MATERIALS AND METHODS

Transoral periosteal thyroidectomies were performed in seven living pigs to evaluate the feasibility and safety of the new approach. Total thyroidectomies were performed in all animals. Follow-up examinations were carried out for 7 days and followed by autopsy.

RESULTS

Through three trocars in the mandibular periosteal area, it was possible to create a working space under the platysma muscle and to reach the pretracheal area. Total thyroidectomies were also performed via the transoral, mandibular periosteal approach without complications in seven orally intubated living pigs. Postoperatively, the white blood cell count remained normal in all cases. On the postoperative sacrifice of the pigs, three locally encapsulated seromas were observed. Both recurrent laryngeal nerves were intact in all cases.

CONCLUSIONS

Transoral periosteal thyroidectomy could be feasible and safe.

Transoral endoscopic thyroidectomy via the tri-vestibular routes: results of a preclinical cadaver feasibility study

The concept of natural orifice transluminal endoscopic surgery (NOTES) is an emerging experimental alternative to conventional surgery that eliminates skin incisions using an endoscope passed through a natural orifice (e.g., mouth, urethra, or anus). This study was designed to evaluate the feasibility and safety of thyroid resection via an entirely transoral tri-vestibular route using endoscopy, and to introduce NOTES to the head and neck area of medicine. We performed ten complete endoscopic thyroid lobectomies with central lymph node dissection via a tri-vestibular approach in fresh-frozen cadavers. A 5-mm endoscope with a deflectable tip was used to visualize the surgical field. Three cannulas were inserted through the midline and bilateral incision sites in the vestibule to position the instruments and endoscope. We refined and described the surgical technique in each step using video clips. We identified and preserved neighboring critical structures during surgery. We also confirmed that there were no obvious remnant thyroid tissues and no injury to the neighboring structures after exploration. The transoral tri-vestibular approach seems to provide a good view and surgical field for endoscopic thyroidectomy. However, the transoral approach for thyroidectomy remains experimental, and the detailed surgical technique should be refined via further clinical studies.

Neck dissection through a facelift incision

OBJECTIVES/HYPOTHESIS

To determine the feasibility and safety of neck dissection through a facelift incision.

STUDY DESIGN

Prospective case series.

METHODS

Cadavers and live subjects underwent neck dissection using a facelift incision with and without endoscopic assistance. In the live facelift neck dissection (FLND), the preoperative surgical indications, staging, adjuvant therapy, intraoperative technical procedure, pathology reports on lymph nodes, and short-term outcomes were reviewed.

RESULTS

FLND was successfully performed in four cadavers and four live subjects, including selective (less than five neck levels removed) and comprehensive (levels I-V removed) neck dissections. All levels were accessible through this approach, with additional retraction required for levels I and IV. Endoscopic assistance was required in one neck dissection for adequate visualization. Short-term complications and number of excised lymph nodes were comparable to those from traditional neck dissection approaches.

CONCLUSIONS

Open neck dissection through a facelift incision is feasible and offers an alternate approach to traditional incisions. This can be performed without requiring robotic assistance and with endoscopic assistance only in certain cases. Endoscopic assistance can offer enhanced visualization of the surgical field and complement open direct approaches in neck dissection. Although FLND offers improved cosmetic outcomes when compared to those of traditional neck incisions, further study is required to determine its efficacy and indications.

Feasibility of Endoscopic Transoral Surgical Lung Biopsy in a Live Canine Model

Background. The feasibility of using a transoral approach to the thoracic cavity has not yet been measured in humans or animals. The present study aimed to evaluate the feasibility of transoral surgical lung biopsy (TOLB) in 10 canines. Methods. Through an incision over the vestibulum oris, a homemade metal tube was introduced into the thoracic cavity under endoscopic guidance and used as a working channel of surgical lung biopsy. TOLB was performed on the predetermined lung lobe by using an electrocautery loop and endoscopic grasper. Results. Successful surgical lung biopsy was achieved in 8 of 10 animals in a mean time of 132 minutes (range 130-190 minutes). There were no major intraoperative or postoperative complications, and all animals survived for 2 weeks after surgery. Autopsy showed no evidence of vital structure injury, mediastinitis, or empyema. Conclusions. TOLB was demonstrated to be safe and feasible in a canine model.

Endoscopic minimally invasive thyroidectomy (eMIT): a prospective proof-of-concept study in humans

BACKGROUND

We have developed a new approach for endoscopic minimally invasive thyroidectomy (eMIT) in anatomical studies. Safety and feasibility were demonstrated in an animal study and then the eMIT technique was applied for the first time successfully in humans on the 18 March 2009.

METHODS

In a prospective study, we performed this eMIT technique on eight patients suffering from nodular change of the thyroid gland. All patients were evaluated regarding recurrent laryngeal nerve function, intra- and postoperative complications, and postoperative outcome, particularly with respect to swallowing disorders.

RESULTS

A total thyroidectomy and a partial resection were performed in four cases each. In three cases, a conversion to open surgery was necessary due to specimen size. No local infection at the incision site or within the cervical spaces occurred within the direct postoperative course. No intraoperative bleeding necessitating conversion to open surgery was observed. In one case, a permanent palsy of the right recurrent laryngeal nerve was noted. Voice function and breathing were not affected. Paresthesia of the mental nerve did not occur in all patients and in those in which it did occur, it resolved within 3 weeks. Mean follow-up time was 10.9 months.

CONCLUSIONS

The experimental development of the eMIT technique has led to its first clinical application in humans. In this prospective proof-of-concept study in humans, the thyroid gland was reached via the transoral endoscopic approach in an anatomically defined layer without any relevant damage to vessels. Limitations to this technique are determined by specimen volume (up to 30 ml) and nodule size (up to 20 mm).