Recomendaciones sobre el uso de la neuromonitorización en cirugía de tiroides y paratiroides

Intraoperative nerve monitoring in thyroid and parathyroid surgery: a decade of Italian practice

Intraoperative nerve monitoring (IONM) has been recognized as a useful adjunct into the field of thyroid and parathyroid surgery, aiding in the accurate identification and preservation of the recurrent laryngeal nerve (RLN), consequently reducing the probability of nerve injury and promoting surgical safety. This investigation seeks to amplify the findings of a similar nationwide survey performed in 2014 by offering an updated assessment of IONM practices among Italian surgical institutions, reflecting a decade of advancements and transformations in clinical approaches. A comprehensive nationwide survey was implemented targeting Italian endocrine surgeons to assess the prevalence, utilization patterns, attitudes and perceptions surrounding IONM in the context of thyroid and parathyroid surgical procedures. Structured questionnaires were administered to seventy endocrine surgery centers, and the resulting data were evaluated employing both quantitative and qualitative analysis methods. The survey disclosed that 67.14% of the participants confirmed the routine deployment of IONM across all cervical surgical procedures, particularly in high-risk contexts. Relative to the findings from 2014, a marked rise in the implementation of IONM has been recorded; however, variability persists, especially between continuous and intermittent monitoring strategies. Surgeons recognized improved surgical safety, decreased complication frequencies, and educational advantages as significant key drivers for the incorporation of IONM. Nonetheless, issues, such as false-positive and false-negative results, along with the lack of standardized protocols, remain barriers to its uniform application. During the past ten years, IONM has been thoroughly adopted by Italian endocrine surgeons as a result of its critical contribution to the improvement of surgical outcomes and the provision of educational resources. However, the results highlight the imperative for further standardization of protocols, the advancement of training programs, and the resolution of reimbursement obstacles to ensure equitable and consistent application of IONM across Italian centers, ultimately optimizing patient care.

Patterns and indications of intraoperative nerve monitoring usage during thyroidectomy and parathyroidectomy in Spain: results of a national survey of endocrine surgeons

We investigated the use patterns and indications of intraoperative neural monitoring (IONM) among endocrine surgeons in Spain. We sent an anonymous web-based survey to endocrine surgeons' members of the Spanish Association of Surgery by email. We analysed 79/ 269 surveys. Respondents had a median age of 52 years and 13 years of surgical experience. Only 32% of respondents performed routinely preoperative laryngoscopy in all thyroidectomies and 19% in all parathyroidectomies. Seventy-five percent of respondents used the intermittent-IONM, and 9.7% used the continuous-IONM. All respondents identified recurrent laryngeal nerve during surgery, and 40% of surgeons routinely identified external branch superior laryngeal nerve (EBSLN) during thyroidectomy. Seventy-eight percent of respondents used IONM always for all thyroidectomies. Only 11% stimulated EBSLN in all cases. Forty-nine percent used IONM always for all parathyroidectomies. The most frequent reasons for not using IONM were the unavailability of IONM, the high cost, and the lack of adding value to their clinical practice. Almost 10% declared not having IONM. The IONM is a reality in Spain, especially the intermittent mode. Its use is superior in thyroid surgery than in parathyroid. Its standardized use is not yet fully established, and routine adherence to standardized guidelines should increase.

The weepy cry - short neural signal bursts in intraoperative neuromonitoring

PURPOSE

This study aimed to establish an in-vitro alternative to existing in-vivo systems to analyze nerve dysfunction using continuous neuromonitoring (C-IONM).

METHODS

Three hundred sixty-three recurrent laryngeal nerves (RLN) (N(pigs) = 304, N(cattle) = 59) from food industry cadavers were exposed by microsurgical dissection following euthanasia. After rinsing with Ringer's lactate, they were tempered at 22 °C. Signal evaluation using C-IONM was performed for 10 min at 2 min intervals, and traction forces of up to 2N were applied for a median time of 60 s. Based on their post-traumatic electrophysiological response, RLNs were classified into four groups: Group A: Amplitude ≥ 100%, Group B: loss of function (LOS) 0-25%, Group C: ≥ 25-50%, and Group D: > 50%.

RESULTS

A viable in-vitro neuromonitoring system was established. The median post-traumatic amplitudes were 112%, 88%, 59%, and 9% in groups A, B, C, and D, respectively. A time-dependent further dynamic LOS was observed during the 10 min after cessation of strain. Surprisingly, following initial post-traumatic hyperconductivity, complete LOS occurred in up to 20% of the nerves in group A. The critical threshold for triggering LOS was 2N in all four groups, resulting in immediate paralysis of up to 51.4% of the nerves studied.

CONCLUSION

Consistent with in-vivo studies, RLN exhibit significant intrinsic electrophysiological variability in response to tensile forces. Moreover, nerve damage progresses even after the complete cessation of strain. Up to 20% of nerves with transiently increased post-traumatic amplitudes above 100% developed complete LOS, which we termed the "weepy cry." This time-delayed response must be considered during the interpretation of C-IONM signals.

Laryngeal paralysis detected in preoperative laryngoscopy in malignant and benign thyroid disease. Systematic review and meta-analysis

There is controversy regarding the performance of preoperative laryngoscopy (LP) in thyroid surgery, with different recommendations being made, based on observational studies, in various publications. The aim of the study was to know the prevalence of laryngeal paralysis found in the LPs of patients who underwent thyroidectomy in benign and malignant pathology. A systematic review was carried out with 29 articles included for the qualitative study and a meta-analysis of 13 articles in which the data could be obtained to evaluate the same effect (in all patients in which an LP was carried out, those with preoperative laryngeal paralysis were included, and assigned to malignant or benign postoperative histology groups). The pooled prevalence of preoperative paralysis in benign pathology was 1.1% (95% CI 0.7 to 1.7%, 71% I²) and in 6.3% malignant pathology (95% CI 3.8 to 9.4%; I² 85%). The prevalence was significantly higher among patients with malignant pathology with an estimated effect RR 5.66, 95% CI, 2.48, 12.88. The studies analyzed present biases that will need to be corrected in future research, eliminating blinding biases in the selection and allocation of patients or in the laryngoscopy technique used. The LP in thyroid surgery evaluates possible disorders of laryngeal motility. The prevalence of laryngeal paralysis in thyroid pathology found in LPs in patients with a postoperative diagnosis of malignant pathology was higher than in the benign pathology group. This information is necessary for interpreting the intraoperative neuromonitoring signal and for making informed decisions.