Introduction

Over the past 20 years ultrasound (USN) has become an increasingly important tool for physicians across all medical specialties. Since the first diagnostic application of USN in 1942, there has been and continues to be significant improvement in available USN machines. They have become simple to use, compact, and portable enough to have in the physician’s office or bring to the patient’s bedside without compromising image quality. USN is quick to perform and can be an extremely helpful extension of the physical exam to diagnose and treat a wide range of disorders. USN allows the clinician to perform a simple bedside diagnostic exam and make an immediate decision regarding further diagnostic exams or treatment; however, there are some drawbacks to USN. The image quality generated and the interpretation of those images is extremely operator-dependent, so it is important that the clinician understand the physics of USN and artifacts that will normally be created as sound waves travel through different tissues, and be able to distinguish normal from abnormal findings.

Use of USN by endocrine surgeons has dramatically increased in recent years. Presently, optimal training and certification requirements have not been standardized at the resident, fellow, or attending level. Hospital privilege requirements for surgeon-performed USN vary. The sensitivity and specificity of USN varies widely depending on the skill and experience of the sonographer, making adequate training paramount to the effective application of this imaging modality in patient care. The purpose of this study was to carry out an international survey to learn more about the types of USN training endocrine surgeons receive in different areas of the world and how they employ USN in practice. We hypothesized that in more recent years fellowship-trained endocrine surgeons were more likely to receive formal training in the use of USN during their endocrine surgery fellowship.

Materials and methods

A questionnaire was sent via email to all members of the International Association of Endocrine Surgeons (IAES) and American Association of Endocrine Surgeons (AAES). The survey included topics ranging from the settings in which the participants received USN training, the type of USN instruction received (formal or informal), level of comfort performing and interpreting USN images, current use of USN in daily practice, as well as various questions related to billing, reimbursement, and medicolegal issues. Specific questions related to USN use in patients with thyroid and parathyroid disease were also asked. After 6 weeks, responses were collected from Survey Monkey (www.surveymonkey.com) and analyzed. Results were analyzed using responses from the entire group as well as several subgroups. Subgroups included those who pursued a clinically oriented fellowship in endocrine surgery and those who were or were not currently using USN in their clinical practice. Results are reported using descriptive methods and χ2 analysis; P < 0.05 was considered significant. This study was approved by the University of Michigan institutional review board.

Results

One hundred twenty-one responses were collected from IAES and AAES members in 27 countries (Fig. 1). There is some overlap in membership between the two groups. Surveys were sent to 335 IAES members and 167 AAES members, not all of whom are practicing endocrine surgeons. The overall response rate was 24%. Membership categories (active, retired, other) were not available for the IAES. Of the AAES members, 36 (22%) were “corresponding members” from other countries who may also be members of the IAES. We were not able to identify how many active AAES members were also members of the IAES. Taking this possible overlap of members into consideration would increase the response rate.

Fig. 1
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Responses to survey by country of origin

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A summary of USN training obtained and current use of USN among respondents is given in Table 1. Median time from completion of surgical training to the present was 17 years (range = 2–49). Seventy-six percent of respondents practice in large hospitals with more than 500 beds. International respondents had more experience with USN as medical students than those in the U.S. (15 vs. 6%, P = 0.037). USN experience among residents from the U.S. and other countries was not different (36% U.S. vs. 29% international, P = 0.13). The most common types of USN performed as a resident included head/neck, intraoperative, gallbladder, and trauma USN. Of those who performed USN examinations during residency training, 28.5% received “formal” training. The term “formal” designated a course with both a didactic session and a hands-on practical session. Forty-one percent (7/17) of these “formal” courses were institution specific and did not include certification by a named group.

Table 1 Description of ultrasound training and current use
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Fifty-nine percent of respondents reported completing an endocrine surgery fellowship; of those, 83% (60/72) reported no formal USN training during fellowship training. Forty percent of fellowship-trained endocrine surgeons reported not being comfortable performing USN at the completion of their fellowships, requiring the presence of someone else to assist with the exam (Fig. 2). Sixty-six percent were unable to consistently perform and interpret USNs on their own. Sixty-one percent never performed an USN-guided fine-needle aspiration (FNA) during their fellowship, despite the fact that FNA of a thyroid nodule is the most frequently performed office procedure in an endocrine surgeon’s office. We found that there has been no significant increase in USN training during fellowship training when surgeons who finished training in the last 10 years (14.8%) were compared with those who finished training more than 10 years ago (19.5%, P = 0.22). Thirty-one percent of endocrine surgery fellowship-trained respondents pursued USN training after entering practice compared with 38% who were not fellowship-trained (P = 0.10). Of 74 total courses taken, 50 (68%) were based in the U.S. and were associated with an organization. Seven (9%) courses were affiliated with internationally based organizations. The remaining 17 (23%) courses were institution based.

Fig. 2
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Level of comfort in performing and interpreting USN exams at the end of endocrine surgery fellowship training

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With regard to the current use of USN, 60% of respondents use USN for thyroid and parathyroid disorders. Respondents reported performing a median of 150 (range = 5–6000) thyroid and 28 (range = 0–3000) parathyroid USNs on an annual basis. The median number of USN-guided thyroid FNAs performed annually was 50 (range = 0–200) and parathyroid FNAs was 0 (range = 0–20). Thirty-eight percent reported no USN training (basic or other specialty USN) of any kind (47% international vs. 23% U.S., P < 0.05). Of the 40% who do not currently use USN, 48% reported that they plan on performing USN in the future. Various reasons were given for those who do not plan on using USN in the future, including financial reasons, referral patterns, good support from radiology colleagues, and interdepartmental politics affecting ability to perform USN. Twenty-five percent reported resistance by other groups in their hospital to their performing USN. Three respondents (2.4%) reported having been denied privileges to perform USN by their hospital. Questions and responses related to billing and reimbursement are given in Table 2. In assessing the level of comfort in performing USN exams, specific questions were asked to determine the survey participant’s willingness to rely on one’s own thyroid USN exam as opposed to referring the patient to a radiologist. The questions and responses are listed in Table 2. Responses to questions related to parathyroid disease are also in Table 2.

Table 2 Survey questions and responses related to thyroid and parathyroid disease, billing, and reimbursement
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At the conclusion of the study, participants were asked about their future plans for USN training. Fifty-four of 116 (47%) responses indicated the desire to pursue further USN training. Sixteen (14%) indicated the desire to pursue further training but indicated inability to do so due to departmental funding, travel issues, or course availability. Forty-six respondents will not be pursuing further USN training because they feel they do not need it. Of these 46, 52% were from the United States, accounting for 54% of U.S. respondents. Twenty-eight percent were international respondents. Only 20/46 (43%) had taken head and neck or thyroid and parathyroid-specific USN courses through an organization providing formal certification.

Discussion

General surgeons and subspecialists are utilizing USN with increased frequency as an extension of the physical exam and for procedures [1]. USN performed by nonradiologists is no longer an exception but is now routine care in many institutions. Bedside USN should become the goal when feasible for streamlining patient care, providing point-of-care testing and diagnosis, and performing therapeutic interventions. Cost effectiveness and time to definitive care for the patient is likely improved when USN is used in this manner. In some cases, it is the surgeon alone who has the most experience performing the specialized USN examination rather than the radiologist or technician [2]. This survey has identified a lack of formal USN training among many endocrine surgeons, including those who perform USN. Training of fellows has not increased despite the increased use of USN over the past decade. While some USN skills can be gained over time by trial and error or via an apprenticeship model, there is no substitute for the knowledge and skills that can be obtained in a short period of time from a formal USN course with didactic and clinical skills sessions. Formal coursework assures a baseline level of knowledge and competence. In clinical practice, application of the knowledge and skills obtained during the USN course allows one to become safe and accurate in performing and interpreting USN examinations.

Limitations of this study include those associated with data garnered from a survey. The response rate was low and, because of the overlap in membership, we cannot be entirely sure of the exact response rate. Members who may not use USN in practice may not have completed the survey if they assumed the title of the survey was not relevant to their practice; this may have led to overestimation of the number of members receiving training in or performing USN. Two respondents were unable to complete the survey due to technical issues and notified the study team. Others may have had technical difficulties but did not notify the study team. The survey was in English which may have prohibited responses from some members. Members who may not use USN in practice may not have completed the survey if they assumed the title of the survey was not relevant to their practice.

Current USN training models

Physicians in some specialties such as obstetrics/gynecology and emergency medicine have performed USN as part of their practice for many years. Obstetricians and gynecologists are trained to perform and interpret pelvic USN on some level. In 1991, the Academy of Emergency Medicine set forth USN training guidelines and specifications for their residency programs. In 1995, the American College of Surgeons (ACS) Committee on Emerging Surgical Technology and Education established the ACS National Ultrasound Faculty (NUF) [3]. The goal of the NUF was to promote surgeon-performed USN. The American College of Graduate Medical Education program requirements for Graduate Medical Education in General Surgery states that programs must ensure that residents have experience with evolving diagnostic and therapeutic methods [4]. This requirement includes USN; however, no specific training guidelines have been set forth, no designations for practical experience have been created, and no testing to determine competency in performing or interpreting ultrasound images has been established. Freitas et al. [5] studied USN training among university and community general surgery residency programs but did not comment on the differences between those who received formal training and those who received informal training. Formal coursework in the trauma realm has been shown to significantly improve scores in both performance and interpretation of USN images obtained in trauma patients [6]. The ACS has provided questions related to USN to the American Board of Surgery, and these questions appear in the written qualifying board examination for general surgery.

This lack of guidelines for training in performance and interpretation of USN carries over to postgraduate training and physicians in practice. Currently, there are no guidelines for ultrasound training for endocrine surgery fellows, endocrinology fellows, or practicing endocrine surgeons. Prior to certification in medical endocrinology, the American Board of Internal Medicine requires 24 months of training (12 of which must be clinical) and the ability to perform thyroid aspiration biopsy [7]. There is no mention of learning USN-guided FNA of thyroid nodules or requirement of performing a specific number of successful aspiration procedures. A head and neck USN course for surgeons is available in the U.S. through the ACS, and thyroid/parathyroid USN courses for surgeons and endocrinologists are available through the American Association of Clinical Endocrinologists (AACE).

AACE has teamed up with the American College of Endocrinology (ACE) to certify physicians performing thyroid and parathyroid ultrasound. Endocrine Certification in Neck Ultrasound (ECNU) requires documentation of 15 h of continuing medical education in ultrasound, successful completion of a comprehensive examination, and completion of the validation of competency process which includes submission of 15 USN studies and reports for verification of accuracy. Importantly, the ECNU is recognized by the American Institute for Ultrasound in Medicine (AIUM) which provides accreditation to physician practices performing dedicated thyroid/parathyroid ultrasound. A growing number of insurers have made practice accreditation a privileging requirement for physicians to be reimbursed for diagnostic imaging.

While the ACS addresses and promotes USN education, it does not address expertise, verify experience, or document competency in surgical practice. Surgical subspecialty societies such as the American Society of Breast Surgeons (ASBS) have partnered with the ACS to develop breast USN performance guidelines for documenting experience and certifying competence, which are cornerstones for credentialing. Certification by the ASBS requires documentation and assessment of training, clinical experience, and quality assurance in diagnostic and interventional breast ultrasound.

For safety reasons, it will likely be mandatory to use USN for imaging guidance when performing certain procedures such as central line placement. Complications such as arterial puncture and pneumothorax have been significantly reduced as a result of using USN guidance for central venous catheter insertion [8–10]. For thyroid nodules, USN guidance is advantageous to ensure aspiration of material from the most concerning portion of a nodule.

Future USN training

Because currently there is no formal peer-reviewed assessment tool used by endocrine surgeons to assure that complete and accurate USN examinations are performed, we are unable to show in this study whether receiving formal USN training truly improves outcomes. Some may argue that no formal USN training is needed, but there are no data to support that opinion. Despite a lack of available data to specifically support the need for formal training in thyroid and parathyroid surgery, data related to teaching procedural skills at the graduate medical education level, including ultrasound [6], would suggest that performance and interpretation of thyroid and parathyroid USN would be improved with formal USN training and allow the surgeon to perform more complete and more accurate ultrasound examinations earlier in their clinical experience.

The data in this study clearly show that most graduating endocrine surgery fellows are not comfortable performing USN examinations or USN-guided procedures at the time they enter practice despite the widespread use of USN by practicing endocrine surgeons and the benefits associated with its use. It is the responsibility of a fellowship program to train the fellow in the most widely accepted procedures performed in the specialty and allow the fellow to gain experience with emerging technologies. USN is no longer an emerging technology but a routinely employed diagnostic and therapeutic modality. Standards for USN courses should be developed to provide consistent didactic and practical content and narrow the gap between training and application to assure best practice. A plan should be developed and instituted for the incorporation of formal USN coursework and certification at the fellowship level, if not for all endocrine surgeons performing USN. Because USN has become such an important tool in the evaluation and treatment of endocrine disorders, endocrine surgery organizations such as the IAES and AAES should begin to solidify requirements for training, competency, and certification to ensure similar levels of quality in ultrasound exams performed in patients with thyroid and parathyroid disorders.

Conclusion

USN training among endocrine surgeons varies widely around the world. Despite an increase in the number of formal endocrine surgery fellowships offered, it does not appear that the number of endocrine surgery fellows finishing with formal USN training and certification has increased. Formal certification in USN is achieved by only a minority of practicing endocrine surgeons. It is currently unknown whether there is a difference in competency between endocrine surgeons with formal versus informal USN training.