Abstract
There is still equipoise for the routine use of intraoperative nerve monitoring (IONM) for thyroid surgeries; however, some surgeons tend to use it for various reasons. In our study, we did a national survey to assess the patterns and practice of the use of IONM among surgeons during thyroid surgery in India. A questionnaire survey was sent to surgeons (head and neck surgical oncologists, general surgical oncologists, endocrine surgeons and otolaryngologists) in different zones in India via email, and their responses were analysed. One hundred and one responses were received. The majority of the respondents were head and neck surgical oncologists (n = 56, 55.4%). Forty-three (42.6%) respondents used IONM during thyroid surgeries in this survey. Surgeons with ≤ 15 years of experience performing thyroid surgeries (p = 0.02) and surgeons performing > 50 thyroid surgeries also tended to use IONM. Mostly IONM was used for surgeries on thyroid malignancies (p = 0.016). The respondents used IONM for more than one reason such as medicolegal purposes and surgeon comfort among others. IONM was most often used during redo surgeries (n = 46, 45.5%) and in patients with already one fixed cord (n = 39, 38.6%). The majority felt IONM was not cost-effective (n = 53, 52.5%). The use of IONM during thyroid surgery in our survey was nearly 43%. It was used mostly for surgery for thyroid malignancies, and it was found to be used for more than one reason and indications such as redo surgeries (most commonly).
Supplementary Information
The online version contains supplementary material available at 10.1007/s13193-023-01818-5.
Keywords: IONM, Survey, Surgeons, Thyroid, Malignancy
Introduction
The visualisation of the recurrent laryngeal nerve (RLN) and the external branch of the superior laryngeal nerve (EBSLN) is still considered the gold standard practice for preventing nerve palsy [1, 2]. This along with the anatomical knowledge and the surgical experience of the surgeon is of paramount importance as well to prevent nerve palsy. Intraoperative neuromonitoring (IONM) technique during thyroid and parathyroid surgery has been globally accepted as an adjunct to the gold standard of visual nerve identification [3]. This is despite the equipoise in the available evidence regarding the use of IONM over visual identification in preventing RLN palsy and questionable cost-effectiveness [4–6].
Although there is a lack of compelling evidence, international guidelines by societies on IONM use in thyroid surgery suggest that it has clear utility in neural identification, reduction of transient nerve paralysis, prediction of nerve function and reduction of bilateral cord paralysis [7]. Two recent guidelines by INMSG also suggest that IONM is mandatory for staging planned contralateral lobe surgery if the loss of electromyography (EMG) signal was observed ipsilaterally [8]. These guidelines also suggest that discussion of comprehensive management of RLN is necessary with preoperative laryngeal examination and IONM EMG data when RLN is grossly invaded by the tumour [8, 9].
Feng et al. in their publications have alluded to the increased prevalence of neural monitoring during thyroidectomy in their global survey [10]. However, there is very little or no data regarding the use of IONM during thyroid surgery in the Indian surgical community. Hence, in this survey, we aimed to study the pattern and practice of the use of IONM in thyroid surgeries among a broader surgical community that will provide insight into its use in India. This may pave the way to understanding the frequency of its use, indications, purpose, challenges, and possibilities of its use in the future and in a way give insight regarding the manpower training needed for its use (if necessary).
Materials and Methods
A 25-question survey was generated following a literature review which also had the consensus of all the authors. The survey was divided into two main sections (Supplementary Material); the first section had questions related to the general information regarding thyroid surgeries by the participant. The second section had questions regarding thyroid surgeries and the use of IONM. This study was approved by the institutional review board and was subsequently registered with the Clinical Trials Registry of India (CTRI/2021/11/038295). An electronic questionnaire-based survey was created using Google Forms. The link (http://panela.btninfosolution.in/ltrack?g=1&id=K0wDCAcFCQYBBB1SBVIDBAMBVEU=WwAHD0xQRkQKCkdYBFlaDHADXFYPCUgCDAs=&client=142026&c=0000) (Supplementary file.1) with an introductory message explaining the purpose of the survey was sent by mail and widely circulated among the head and neck surgical oncologists, general surgical oncologists, endocrine surgeons and otolaryngologists across the entire country and different zones such as the east, west, north, south and central zone. The anticipated time to complete the survey was 5 min, and the survey link was kept open for 4 weeks only and subsequently closed. Reminder emails were sent once every 10 days. Once the survey was closed, the responses were downloaded for analysis.
The statistical analysis was performed using the SPSS 24 (IBM Corp, Armonk, NY) software. Quantitative analysis of the responses to the survey questions was done to understand the general information related to thyroid surgeries by the respondents and to understand their use of IONM in thyroid surgeries. Fisher’s exact test was used for any significant associations about the use of IONM in thyroid surgeries. p < 0.05 was considered significant by the responders.
Results
The questionnaire was mailed to 879 recipients, of whom 286 clicked and opened the mail. Of these 286 unique openings, 101 answered the questionnaire. Thus, the response rate (no. of recipients answering the questionnaire/no. of recipients opening the mail × 100) was 35.3%. The completion rate (no. of recipients who completed the survey/no. of recipients who started the survey × 100) was 100%. The lower response rates probably indicate the lack of penetration of IONM technology in the country as such.
Out of the 101 responses received, the majority of 49.5% responders were from government/public-funded hospitals followed by 33.7% from private/corporate hospitals and 16.8% from NGO-based centres. The majority of the respondents were head and neck surgical oncologists (n = 56, 55.4%). The responders were almost equally spread across different years of experience (Fig. 1) (Table 1). Majority of the respondents performed more than 50 thyroid surgeries in a year (n = 42, 41.6%). Most surgeons performed thyroid surgery for malignant pathology among the respondents (n = 42, 41.6%). As per the zones from across the country, the maximum response was seen from the west and south zones (Fig. 4, Supplementary), and the use of IONM during thyroid surgery was 42.8% (9/21) in the north zone, 42.8% (3/7) again from east zone, 61.5% (24/39) from west zone, 22.5% (7/31) from south zone and none from central zone (0/3). The city/town wise distribution is given in Table 2 (Supplementary).
Fig. 1.
Details regarding the respondents’ speciality, duration of years of practice, volume of surgeries done, thyroid pathology and use of IONM
Table 1.
Responses of the participants to the various survey questions
| Variables | Numbers (%) |
|---|---|
| Respondents’ speciality | |
| Head and neck surgical oncologists | 56 (55.4%) |
| General surgical oncologists | 21 (20.8%) |
| Endocrine surgeons | 13 (12.9%) |
| Otolaryngologists | 11 (10.9%) |
| Respondents’ region | |
| North zone | 21 (20.8%) |
| South zone | 31 (30.7%) |
| East zone | 7 (6.9%) |
| West zone | 39 (38.6%) |
| Central zone | 3 (3%) |
| Type of hospital setup of the respondents | |
| Government/public-funded hospital | 50 (49.5%) |
| Private/corporate hospitals | 34 (33.7%) |
| NGO/others | 17 (16.8%) |
| Duration of years performing thyroid surgeries | |
| < 5 years | 23 (22.8%) |
| 6–10 years | 20 (19.8%) |
| 11–15 years | 24 (23.8%) |
| 16–20 years | 15 (14.9%) |
| > 20 years | 19 (18.8) |
| Numbers of thyroid surgeries performed per year | |
| < 10/year | 8 (7.9%) |
| 11–25/year | 27 (26.7%) |
| 26–50/year | 24 (23.8%) |
| > 50/year | 42 (41.6%) |
| Thyroid pathology for which surgery was performed | |
| Benign | 9 (8.9%) |
| Malignant | 42 (41.6%) |
| Both | 50 (49.5%) |
| Is there evidence for use of IONM presently in thyroid surgeries? | |
| Yes | 23 (22.8%) |
| No | 51 (50.5%) |
| Maybe | 27 (26.7%) |
| Do you use IONM presently for thyroid surgeries? | |
| Yes | 43 (42.6%) |
| No | 58 (57.4%) |
| Since how years has IONM been used for thyroid surgeries? | |
| < 1 year | 9 (8.9%) |
| 1–5 years | 28 (27.7%) |
| 6–10 years | 4 (4%) |
| > 10 years | 4 (4%) |
| No response | 56 (55.4%) |
| Who operates the IONM for you? | |
| Self | 13 (12.9%) |
| Anaesthetists/other doctors | 10 (9.9%) |
| IONM technician | 24 (23.8%) |
| No response | 54 (53.5%) |
| Reason for use of IONM during thyroid surgeries | |
| Reduces nerve injuries | 35 (34.7%) |
| For nerve identification | 39 (38.6%) |
| Medico legal purpose | 43 (42.6%) |
| For patient safety | 38 (37.6%) |
| For training purpose | 23 (22.8%) |
| For surgeon comfort | 53 (52.5%) |
| Is there a decrease in the palsy rates after the use of IONM? | |
| Yes | 9 (8.9%) |
| No | 20 (19.8%) |
| Maybe | 23 (22.8%) |
| No response | 49 (48.5%) |
| What type of IONM electrode do you use? | |
| Prefabricated endotracheal tube | 11 (10.9%) |
| IONM electrodes | 33 (32.7%) |
| Both | 5 (5%) |
| No response | 52 (51.5%) |
| When do you use IONM during thyroid surgeries? | |
| Redo surgeries | 46 (45.5%) |
| Advanced cases | 30 (29.7%) |
| Multiple central compartment nodes | 28 (27.7%) |
| Already one cord fixed | 39 (38.6%) |
| Patients request | 22 (21.8%) |
| Does IONM help in the decision-making process during thyroid surgery? | |
| Yes | 37 (36.6%) |
| No | 25 (24.8%) |
| Maybe | 39 (38.6%) |
| How does IONM help during thyroid surgery? | |
| Nerve identification | 5 (5%) |
| Nerve sacrifice | 3 (3%) |
| To decide on staging surgery | 18 (17.8%) |
| To confirm functional integrity of the nerve | 6 (5.9%) |
| No response | 69 (68.3%) |
| Is IONM cost-effective? | |
| Yes | 16 (15.8%) |
| No | 53 (52.5%) |
| Maybe | 32 (31.7%) |
| Do you think IONM adds to the cost? | |
| Yes | 75 (72.3%) |
| No | 6 (5.9%) |
| Maybe | 20 (19.8%) |
| Would you use IONM in the future? | |
| Yes | 18 (17.8%) |
| No | 6 (5.9%) |
| Maybe | 42 (41.6%) |
| No response | 35 (34.7%) |
| Reasons for not using IONM present | |
| Unavailability | 31 (30.7%) |
| Increased risk of palsy | 3 (3%) |
| Cost issues | 21 (20.8%) |
| No change in outcome | 14 (13.9%) |
| Sensitivity and specificity issues | 10 (9.9%) |
Use of IONM in Thyroid Surgeries
In our survey, only (n = 43) 42.6% of the responders used the IONM regularly, whereas 57.4% never used IONM. IONM was often used for malignant pathology (p = 0.016) as compared to benign. Most of them were using IONM for 1–5 years (n = 28, 27.7%) only. Reasons cited for not using IONM were unavailability (30.7%) and cost issues (20.8%) among others (Table 1). When IONM was being used, it was operated by either an IONM technician (n = 24, 23.8%) or anaesthetist (n = 10, 9.9%) or by self (n = 13, 12.9%). IONM was commonly used in the following scenarios such as redo cases (n = 46, 45.5%), presence of preoperative vocal cord paralysis on one of the sides (n = 39, 38.6%) and advanced cases (n = 30, 29.7%) among others (Fig. 2) (Table 1).
Fig. 2.
Responses regarding reasons and when IONM was used
Most of the surgeons who used IONM indicated doing commonly with prefabricated EMG-ET tubes (n = 11, 10.9%) and IONM needle electrodes (n = 33, 32.7%). Only 5% (n = 5) of the responders used both prefabricated tubes and needle electrodes depending upon the intraoperative disease status. Thirty-seven (36.6%) of respondents agreed that IONM helps in the intraoperative decision-making process, while 24.8% of the responders felt that IONM did not help in the intraoperative decision-making process during thyroid surgery. Eighteen respondents (17.8%) felt IONM was useful in staging surgery in the presence of loss of signal, etc. (Fig. 2) While a few others felt IONM was useful in identifying the recurrent laryngeal nerve (n = 5), deciding nerve sacrifice (n = 3) and confirming the functional integrity of the nerve (n = 6). The majority of the respondents felt that the use of IONM was not cost-effective (n = 53, 52.5%), and its use added to the cost of the surgery (n = 75, 72.3%). Also, many respondents felt that the use of IONM did not reduce their palsy rates (n = 20, 19.8%).
We noticed that among the respondents, surgeons with ≤ 15 years of experience performing thyroid surgeries (p = 0.02) tended to use IONM as compared with those with > 15 years of experience. Also, surgeons who perform more than 50 surgeries in a year were more interested in using IONM significantly (p = 0.034) routinely as compared to surgeons who operate fewer procedures. Those who believed that there was enough evidence to use IONM put their belief into practice (p = 0.04). Those who used IONM had multiple reasons for it which were statistically significant (p = 0.005).
Discussion
Our study presents the findings of the first national survey conducted on the use of IONM in thyroid surgeries. Among the respondents, 43 (42.6%) surgeons used IONM during thyroid surgeries out of the 101 surgeons who responded to the survey. Most of the participating surgeons regard IONM as an important tool in redo surgeries, advanced cases and particularly for the staging surgery, though they felt that it added to the cost of the surgery.
Ever since the work of Lahey and Hoover [2], direct visualisation of the recurrent laryngeal nerve (RLN) has remained the gold standard for the prevention of RLN palsy during thyroid surgery. Despite visual identification of RLN, temporary palsy still can occur in 2% to 8% of cases and permanently in 0.5% to 3% of cases [11, 12]. The use of IONM in thyroid surgery has been widely accepted the world over; a global survey by Feng et al. commented that IONM use in thyroid surgeries has been two times more than what it was in the past decade [10]. Though there are no uniform recommendations for the use of IONM in thyroid surgeries, certain guidelines such as the AAO-HNS and AHNS acknowledge the benefits of the use of IONM [13, 14] and recommend considering the use of IONM in all cases of thyroid cancer surgeries [12], whereas the German Association of Endocrine Surgery recommends the routine use of IONM in all cases of thyroid surgeries [15].
In the global survey by Feng AL et al., 83% of the respondents reported using IONM during thyroidectomy. Surgeons ≤ 45 years of age and those ≤ 15 years of practice used IONM frequently. There was no correlation with the thyroid surgery volume or type of practice setup [8]. In our survey, surgeons across different years of practice tended to use IONM during thyroid surgery; however, collectively, surgeons ≤ 15 years of practice used IONM frequently. Also, surgeons performing > 50 thyroid surgeries/year used IONM. These surgeons were also willing to use it continuously in the future as well. There was no difference in the use of IONM based on the type of practice (public-funded/private/NGO-based hospitals). Those who felt that there was enough evidence to use IONM did use it. Similar findings were reported by Horne et al. in their survey from the USA [16].
In our survey, most surgeons who were using IONM used it for one of the following indications such as during redo surgeries, in advanced cases, in the presence of multiple central compartment nodes, in a patient with already one cord fixed and on patient request at times. When IONM was used, it was done so for more than one reason. Among those who used IONM during thyroid surgery, 5% felt it was useful in identifying the nerve; 3% felt it was useful in deciding nerve sacrifice; 5.9% felt it was helpful in confirming the functional integrity of the nerve and 17.8% found it useful to decide on staging surgery. However, some respondents (19.8%) who used IONM felt that its use did not reduce the palsy rates. Overall, many of the respondents in our survey felt that the use of IONM was not cost-effective (52.5%), and its use added to the cost of the surgery (72.3%). Respondents did not use IONM during thyroid surgery for reasons such as unavailability (30.7%) and cost issues (20.8%) among others.
The use of IONM is associated with a learning curve in about 50–100 thyroid surgery cases, which may be associated with the arrangement of the entire IONM setup and for the entire surgical team to learn the troubleshooting algorithm [17, 18]. Hence, generally, the number of practicing surgeons using IONM has increased based on the availability of neurophysiologists/technologists globally. In our study, the ones who were using IONM were managed by the surgeons themselves, anaesthetists or the IONM technicians. In our survey, the IONM electrodes were used more often in comparison to the prefabricated EMG-ET tube. Feng et al. reported in their survey the use of regular ET tubes with adhesive electrodes [10]. At our centre, we prefer to use prefabricated ET tubes whenever possible. However, the IONM needle electrodes may have their use, particularly in the presence of more advanced disease, unavailability of the prefabricated ET tube or difficult airway making intubation with the prefabricated tube difficult.
The strength of our study is that it is the first report on the various practices and patterns of use of IONM from India. Hence, it gives us a reasonable idea regarding its use in the country. The main limitation is the lower response rate which could also be a reflection of the poor penetration of the use of IONM in our country.
Conclusion
In our study, we see that the use of IONM was seen among 42.6% surgeons (43 out of the 101 surgeons who responded to the survey) performing thyroid surgery in India. The use of IONM was more among surgeons with ≤ 15 years of experience with performing thyroid surgery. Most of them used IONM for more than one reason and in difficult and redo cases. The majority felt that the use of IONM was adding to the cost of the surgery. The results of this survey convey some information about the patterns and practices of IONM use in thyroid surgery in India.
Supplementary Information
(PNG 1197 kb)
(DOCX 41 kb)
(DOCX 15 kb)
Data availability
On request
Declarations
Ethical Approval
Approval from our institute ethics committee (project no.:900867) was taken and registered with the Clinical Trials Registry of India (CTRI/2021/11/038295) (date of registration-26/11/21).
Consent to Participate
No identifying information about participants is available in the article. However, all patients have given consent for the treatment they have received.
Conflict of Interest
The authors declare no competing interests.
Footnotes
Conference Presentation
This study was presented as a poster at FHNO 2022 conference at Guwahati, Assam, India.
Publisher’s Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
References
- 1.Riddell VH. Injury to recurrent laryngeal nerves during thyroidectomy; a comparison between the results of identification and non-identification in 1022 nerves exposed to risk. Lancet. 1956;271(6944):638–641. doi: 10.1016/S0140-6736(56)92333-9. [DOI] [PubMed] [Google Scholar]
- 2.Lahey FH, Hoover WB. Injuries to the recurrent laryngeal nerve in thyroid operations: their management and avoidance. Ann Surg. 1938;108(4):545–562. doi: 10.1097/00000658-193810000-00006. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Périé S, Santini J, Kim HY, Dralle H, Randolph GW. International consensus (ICON) on comprehensive management of the laryngeal nerve risks during thyroid surgery. Eur Ann Otorhinolaryngol Head Neck Dis. 2018;135(1S):S7–S10. doi: 10.1016/j.anorl.2017.11.010. [DOI] [PubMed] [Google Scholar]
- 4.Cirocchi R, Arezzo A, D'Andrea V, et al. Intraoperative neuromonitoring versus visual nerve identification for prevention of recurrent laryngeal nerve injury in adults undergoing thyroid surgery. Cochrane Database Syst Rev. 2019;1(1):CD012483. doi: 10.1002/14651858.CD012483.pub2. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Davey MG, Cleere EF, Lowery AJ, Kerin MJ. Intraoperative recurrent laryngeal nerve monitoring versus visualisation alone - a systematic review and meta-analysis of randomized controlled trials. Am J Surg. 2022;224(3):836–841. doi: 10.1016/j.amjsurg.2022.03.036. [DOI] [PubMed] [Google Scholar]
- 6.Rocke DJ, Goldstein DP, de Almeida JR. A cost-utility analysis of recurrent laryngeal nerve monitoring in the setting of total thyroidectomy. JAMA Otolaryngol Head Neck Surg. 2016;142(12):1199–1205. doi: 10.1001/jamaoto.2016.2860. [DOI] [PubMed] [Google Scholar]
- 7.Randolph GW, Dralle H. International Intraoperative Monitoring Study Group; Electrophysiologic recurrent laryngeal nerve monitoring during thyroid and parathyroid surgery: international standards guideline statement. Laryngoscope. 2011;121(Suppl 1):S1–16. doi: 10.1002/lary.21119. [DOI] [PubMed] [Google Scholar]
- 8.Wu CW, Huang TY, Randolph GW, et al. Informed consent for intraoperative neural monitoring in thyroid and parathyroid surgery - consensus statement of the international neural monitoring study group. Front Endocrinol (Lausanne) 2021;7(12):795281. doi: 10.3389/fendo.2021.795281. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Schneider R, Randolph GW, Dionigi G, et al. International neural monitoring study group guideline 2018 part I: staging bilateral thyroid surgery with monitoring loss of signal. Laryngoscope. 2018;128(Suppl 3):S1–S17. doi: 10.1002/lary.27359. [DOI] [PubMed] [Google Scholar]
- 10.Feng AL, Puram SV, Singer MC, Modi R, Kamani D, Randolph GW. Increased prevalence of neural monitoring during thyroidectomy: global surgical survey. Laryngoscope. 2020;130(4):1097–1104. doi: 10.1002/lary.28210. [DOI] [PubMed] [Google Scholar]
- 11.Bergenfelz A, et al. Complications to thyroid surgery results as reported in a database from a multicenter audit comprising 3,660 patients. Langenbeck's Arch Surg. 2008;393(5):667–673. doi: 10.1007/s00423-008-0366-7. [DOI] [PubMed] [Google Scholar]
- 12.Shindo ML, Caruana SM, Kandil E, et al. Management of invasive well-differentiated thyroid cancer: an American Head and Neck Society consensus statement. AHNS consensus statement. Head Neck. 2014;36(10):1379–1390. doi: 10.1002/hed.23619. [DOI] [PubMed] [Google Scholar]
- 13.Snyder SK, Sigmond BR, Lairmore TC, Govednik-Horny CM, Janicek AK, Jupiter DC. The long-term impact of routine intraoperative nerve monitoring during thyroid and parathyroid surgery. Surgery. 2013;154(4):704–711. doi: 10.1016/j.surg.2013.06.039. [DOI] [PubMed] [Google Scholar]
- 14.Chandrasekhar SS, Randolph GW, Seidman MD, et al. Clinical practice guideline: improving voice outcomes after thyroid surgery. Otolaryngol Head Neck Surg. 2013;148:S1–37. doi: 10.1177/0194599813487301. [DOI] [PubMed] [Google Scholar]
- 15.Musholt TJ, Clerici T, Dralle H, et al. German Association of Endocrine Surgeons practice guidelines for the surgical treatment of benign thyroid disease. Langenbeck's Arch Surg. 2011;396:639–649. doi: 10.1007/s00423-011-0774-y. [DOI] [PubMed] [Google Scholar]
- 16.Horne SK, Gal TJ, Brennan JA. Prevalence and patterns of intraoperative nerve monitoring for thyroidectomy. Otolaryngol Head Neck Surg. 2007;136(6):952–956. doi: 10.1016/j.otohns.2007.02.011. [DOI] [PubMed] [Google Scholar]
- 17.Dralle H. What benefits does IONM bring to thyroid surgery? Arzt und Krankenhaus. 2004;12:369–376. [Google Scholar]
- 18.Wojtczak B, Sutkowski K, Kaliszewski K, et al. Thyroid reoperation using intraoperative neuromonitoring. Endocrine. 2017;58:458–466. doi: 10.1007/s12020-017-1443-x. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
(PNG 1197 kb)
(DOCX 41 kb)
(DOCX 15 kb)
Data Availability Statement
On request