Sir,

Professor Lombardi, Dr. Sartori, Barczyński, and Hallgrimsson reported their comprehensive experience on modern hemostatic devices both in conventional and endoscopic thyroidectomy. I have carefully read these excellent papers. Certainly, these colleagues have made several contributions to the literature, and their valuable contributions have advanced our understanding of the surgical treatment and technique in thyroid surgery.

I would like to offer an additional remark from a prospective point of view.

  • The Food and Drug Administration’s approval of the use of ultrasonic coagulating–dissectioning systems (HCDS) and electrothermal bipolar vessel sealing systems (EBVSS) to seal vessels and parenchyma, in addition to their easy application, significant blood-loss reduction, and commercial effort, made HCDS and EBVSS more attractive for thyroid procedures as an alternative to traditional clamp-and-tie technique and hemostatic clips. Energized dissection systems facilitate dissection, reduce instrument traffic, operative time, analgesics, incision length, and hospital stay, and have similar morbidity compared with traditional surgery and lack of flow of electrical current through the patient [1–4].

  • Intraoperative recurrent laryngeal nerve (RLN) injury causes are manifold and most are due to mistakes of the surgical technique: section of the nerve, ligature, traction during the medialization of the thyroid lobe, suction by aspiration near to the nerve, compression, contusion, pressure, ischemia by excessive skeletization, and finally electrical and thermal injury [5–7]. It is difficult to establish what the prevalence of each of these causes, thus defining the major cause, is [6, 7]. De facto, HCDS, and EBVSS have the potential for invisible and undesirable heat-related collateral/proximity iatrogenic injury to adjacent structures. For the wide availability now in all operating rooms of HCDS and EBVSS, I would expect in the near future more nerve injuries caused by thermal injury. Moreover, several studies have shown that surgeons (even experienced ones) underestimate actual RLN injury [5, 8–11], especially if the injury is invisible, as in the thermal one. In fact, the surgeon’ intraoperative evidence of RLN injury is only between 7.5% to 15% (mean 10%) [5, 8–11].

  • It is therefore essential that the safety of these devices is established before there are widely used on patients [12]. There is little published experimental evidence for HCDS and EBVSS in thyroid surgery. The thermal spread must be studied to determine an average distance of safety of the exposed surface of the instrument near to vital structures such as the RLN, parathyroids glands, and trachea. At present, there are indirect data from other organ studies. Campbell reported a study by using in situ live dynamic infrared thermography for a 360° monitoring (lateral, lower, upper, and tip thermal spread) of an energized dissection/coagulation device during abdominal surgery (gastric, liver, biliary, bowel, and renal) [13]. Unfortunately, no nerve structure measurements were correlated with thermography or histopathologic studies. Defechereux has recently proposed an experimental model of neuromonitoring (NM) as an adjunct to visual identification of nerve injury during HCDS dissection [14]. Electromyographic (EMG) potential with electrophysiologic and pathology of rat sciatic nerves was recorded before and after each experiment. With quantitative correlation of EMG, comparing changes of EMG signal, NM may reflect varying degrees of nerve dysfunction during thermal spread. Preliminary results indicate that HCDS is safer than bipolar devices close to nerves [14], but no definition of the distance of safety of the instrument from a nerve has been reported.

  • With significant technical improvements, the clinical utility of these devices may proliferate. The latest-generation devices have the potential to reduce thermal spread through the use of active feedback control over the power output [13]. This effectively regulates the delivery of energy to the target tissue with minimal thermal collateral damage. Furthermore, innovative heat-sink engineering of the device head ensures that the surface of the instrument tip remains cool [13]. Again, the electrophysiologic and pathology nerve data achieved for NM may be combined in the software of the new device during hemostasis and dissection near a nerve, or in addition, the stimulation electrodes for NM may be incorporated into HCDS and EBVSS, so they can be performed at any time without halting the surgical dissection [15].

  • There are no randomized prospective studies in thyroid surgery comparing HCDS and EBVSS with a high level of evidence and recommendation [16, 17]. Because no differences are observed regarding different devices, the choice should be made based on the surgeon’s preferences and experience. These devices require specific training with a standardization of technique that foresees an abundant distance of safety. Traditional suture ligation and vascular clips remain valuable in thyroidectomy, which avoids the use of HCDS and EBVSS in a critical area near the RLN. Moreover, if a suture ligation or a vascular clip is identified near the RLN and NM reflects RLN dysfunction, these sutures may be taken off of the surgical field; this intraoperative procedure cannot be made for HCDS and EBVSS.

Thank you for the opportunity to write this letter.