Indications and Classical surgical approaches to RG
Classical indications for surgically removing a simple/non-toxic goiter date back to the beginning of the twentieth century: relief from compression symptoms, prevention of or suspicion of an associated malignancy, or for cosmetic purposes51. Unfortunately, these criteria are somehow vague and, because ultimately the surgeon is the sole responsible for the outcomes of thyroidectomy, in 2018 a “Choosing wisely” initiative from Germany proposed more reproducible criteria: compression symptoms (dyspnea, stridor, dysphagia) must be directly attributable to goiter while a reasonable suspicion of malignancy must be documented (i.e. , TI-RADS category 4c/ 5, Tir 3 or higher class at FNAC in the presence of risk factors for thyroid cancer, basal calcitonin serum level increase >26 pmol/L in women and 60 pmol/L in men, cN+ status at ultrasound). In the absence of the above, surgery may also be indicated for “prevention of complications” that may derive from a progressive RG (defined as tracheal compression >35%, superior vena cava syndrome)”52–54. Again the progression must be documented but the very natural history of untreated RG is still poorly understood2.
An exhaustive explanation to the patient and their caregivers is the key to surgical success3. A detailed technical overview of the classical surgical approaches to RG has been recently given by Uludag et al and it will briefly be discussed here39. A Kocher incision, ligation of the superior and inferior vascular peduncles, and digital dissection remain the standard surgical steps, but resection of the pre-laryngeal musculature is often necessary for delivering large goiters. A 2022 study has for the first time evaluated its consequences on vocal and swallowing function: by using patient-reported impairment scores, a prospective head-to-head study of 34 patients revealed no significant differences when strap muscles are transected or not55.
In 2021, the International Neural Monitoring Study Group (INMSG) published the most important study of surgical anatomy since the introduction of intraoperative neuromonitoring (IONM). The authors have meticulously evaluated the course and anatomical relationships of 1000 RLNs: strikingly, among other findings, it emerged that in 50% of cases of RG (versus 30% in standard thyroidectomies), the RLN was fixed, splayed, or entrapped at the level of the capsule of the thyroid, thus rendering at high risk for loss of signal56. IONM is thus mandatory for every RG operation and, in the case of “giant” RG, many authors suggest the upfront use of a transcervical medial approach, which implies the separation of the isthmus and dissection of Berry’s ligament in a layered fashion along the trachea and towards the RLN. In a series from the USA, successful identification of the RLN was reported to be 84% with this approach and postoperative vocal cord dysfunction (assessed by flexible laryngoscopy) was null57. A very high rate (17%) of postoperative hematoma was reported, yet the authors declared that revision in the operative room was deemed necessary only for one patient57. Another larger case series from Greece declared instead no postoperative bleeding, and a permanent RLN damage rate comparable with classic lateral approaches58.
Regarding the extent of the resection, even in the most recent series total thyroidectomy is the preferred strategy for RG, which however can harbor one or more foci of malignancy in up to 40% of cases21. When the intrathoracic part is well lateralized, or there are anatomical constraints or technical issues during the dissection, a subtotal resection or a simple hemithyroidectomy may help relieve the compression symptoms while minimizing the postoperative complications. New technologies are being exploited also in this type of operation: in 2018, some authors have proposed a microdebrider-assisted intracapsular reduction thyroidectomy on a small series of 26 patients. According to the proponents, a standard sinus suction debrider may morcellate the intracapsular part of the RG, it has no effect on the risk of major bleeding, and may avoid the need for sternotomy in selected patients59. Instead, recent retrospective papers on transoral endoscopic thyroidectomy vestibular approach (TOETVA) or transoral robotic thyroidectomy (TORT) consider RG as an exclusion criterion because of intrinsic limitations in terms of surgical exposure60.