Discussion
The technique described has the potential to be a break through in the new procedures that are being used to operate on the thyroid gland. It combines a minimal access with a scar less technique.
The procedure is feasible and has already had human trials. The results were encouraging but not up to a point were the procedure can become a safe replacement of the current procedures used to operate on the thyroid gland. Whether this is solely dependant on a learning curve or modifications need to be made to the procedure, is a question for further investigation.
The limitations we identified in the procedure are as follows:
– mental nerve injury.
– Difficult visualisation of the recurrent laryngeal nerve in its final segment at the level of the ligament of Berry, before it enters the larynx.
– Potential of infection as the access is done via the mouth.
– Inability to remove larger specimen via the floor of the mouth.
– Steep learning curve
– Risk for neck haematoma
In regards to mental nerve injury, we believe that the development of a single port that adapts to the floor of the mouth, is without doubt the next necessary step in advancing this procedure. Introducing new complications is unacceptable as we already have a very safe procedure. Cosmesis alone should not be the guiding force behind the introduction of a new technique.
With respect to the difficult visualisation of the recurrent laryngeal nerve it is likely that this can be minimised if better optics are utilised. It would be necessary to either utilise a system that has the ability to flex the camera or a robotic assisted camera that provides a three dimensional view.
The potential for infection has been brought up in comments upon initial publications of this technique . It is true that a “clean” procedure is converted into a “contaminated” procedure. In our experience in head and neck oncology were floor of the mouth, tongue and other oral cavity tumours are excised along with a neck dissec-
tion, this “contamination” is always present. Despite this, infection rates are low.
This is likely related to the excellent vascularisation that exists in the head and neck providing for minimal infection rates. Open thyroidectomy is an operation with an almost negligible infection rate. The procedure we are analysing would have the potential to increase this infection rate. We do not think an increased risk of infection should deter us from further development of this procedure, as it would be logical to extrapolate results from Head and Neck oncology and their low infection rates.
The inability to remove larger specimen via the mouth can also be overcome in the same way laparoscopic splenectomy overcame the difficulty of removing the specimen via a minimal incision. The specimen is placed in a plastic bag and morcellated.
It may be an option to explore with the pathologists as to whether morcellating or simply subdividing the specimen would compromise the histopathological analysis or not.
Since this study was performed on cadaveric material it is impossible to evaluate the risk of bleeding and the difficulties that intraoperative haemorrhage could potentially cause.
Conclusions
This procedure clearly needs to be further developed, however there is potential for improvement and better technique options. Close relation with the industry to develop custom instruments will be necessary. At this point this procedure is not a replacement of the present open, video assisted or robotic approaches. TOVAT is a technically feasible procedure which offers surgical access to the thyroid without the need for a visible cervical incision or the extensive dissection required in trans-axillary approaches.