Langenbecks Arch Surg (2016) 401:239–247 DOI 10.1007/s00423-016-1390-7
ORIGINAL ARTICLE
Education in thyroid surgery: a matched-pair analysis comparing residents and board-certified surgeons Alexander Reinisch 1 & Patrizia Malkomes 1 & Juliane Liese 1 & Teresa Schreckenbach 1 & Katharina Holzer 1 & Wolf Otto Bechstein 1 & Nils Habbe 1
Received: 14 January 2016 / Accepted: 23 February 2016 / Published online: 1 March 2016 # Springer-Verlag Berlin Heidelberg 2016
Abstract Purpose Resident participation in operative procedures is mandatory in educational residency programs but remains controversial, especially in the context of patient safety. This study compared the surgical quality and outcomes of thyroidectomies performed by surgical residents (RESs) and boardcertified surgeons (BCSs). Methods This retrospective matched-pair study included patients undergoing thyroidectomies for multinodular goiter, Grave’s disease and early-stage thyroid cancer that were performed by a RES with BCS supervision between 2006 and 2014. The intraoperative and postoperative course, complication rates and handling of the recurrent laryngeal nerve (RLN) and parathyroid glands were analyzed. Results In total, 112 thyroidectomies that were performed by a RES fulfilled the inclusion criteria and were matched 1:1 with BCS patients. We included 88 hemithyroidectomies, 80 subtotal thyroidectomies and 56 total thyroidectomies. No significant differences in the handling of the RLN or parathyroid glands, the rates of postoperative RLN palsies or the rates of hypocalcaemia were found. No intraoperative complications led to the replacement of the RES as the surgeon-incharge. Three RES and two BCS patients experienced postoperative haemorrhages (p = 0.205), and three surgical site infections (p = 1.000) occurred in each group. The mean
* Alexander Reinisch [email protected]
1
Department of General and Visceral Surgery, Johann Wolfgang Goethe University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
operative time and the length of stay did not differ significantly between the two groups. Conclusions Major aspects of patient safety in thyroid surgery are not affected by resident participation. Thyroidectomies performed by RES are not significantly longer and reveal no differences in length of stay or complication rates. The economic burden of resident involvement is modest. Keywords Surgical education . Thyroid . Patient safety . Resident involvement . Resident participation
Introduction In addition to the acquisition of theoretical knowledge, the development of practical skills is an important aspect of surgical training. In most countries, the teaching of practical skills is achieved through the involvement of the surgeon-to-be in surgical procedures. Starting as an assistant during interventions with increasing complexity, the trainee will eventually perform operations by himself. These operations will usually be guided, instructed and supervised by a board-certified surgeon (BCS) and will also become more complex during the residency period. Several topics regarding teaching in the operation room (OR) are of particular importance. First, the trainee, the BCS and the patient are in an area of conflicting interests. The trainee must fulfil a curriculum of guided operations and gain technical experience, while the BCS must maintain patient safety, ensure the success of the procedure and consider economic factors. For the patient, the vitally important factor is the success of his treatment and the avoidance of complications. In fact, patients are often concerned about resident participation, and the need for informed consent for resident participation is under discussion [1]. To date, no specific legal
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requirements for resident participation exist in Germany, the USA or the UK. Furthermore, the term Bresident participation^ must be clarified. In studies based on data from the National Surgical Quality Improvement Program (NSQIP), the degree of resident participation remains unclear [2–4]. In addition, most NSQIP-based studies analyzed a combination of different operations. Other studies defined resident participation as the resident acting as first assistant during the operation, for example in Relles’ analysis of residents in pancreatic surgery [5]). Data related to operations performed by residents under the supervision of and with occasional help from the BCS are rare. Several studies demonstrated that resident involvement caused increased operation time [2, 6]. The impacts of surgical resident (RES) on complication rates and outcomes are controversial [2, 6, 7]. Of note, operation time and complication rates are crucial economic factors. Recent publications revealed no differences in surgical quality. Schreckenbach revealed no increases in complication and recurrence rates in proctologic operations, which were often performed by RES of a lower postgraduate year (PGY) [8]. Thyroid operations are an ideal advanced training operation. As a part of the curriculum for general surgery in most countries [9, 10], thyroid surgery necessitates a high-quality surgery because complications could have major implications. Difficile preparation, the localization and protection of smallsized structures and the tactical planning and realization of a multi-step operation are special requirements of the RES in thyroid surgery. On the other hand, the clear sequence of operative steps and the possibility of observing and accessing every region of the operating field allow the supervising BCS to maintain a high degree of control over the operation. In contrast to open abdominal operations, in thyroid surgery, the field of vision is almost identical for both the BCS and the RES. The BCS is not hindered in his ability to intervene by holding organs or providing access to special regions of the situs. Thus, the BCS may ensure patient safety and the success of the operation more easily than in open abdominal surgery. The aim of this study was to investigate the impact of resident participation on the quality of thyroid operations and postoperative complication rates.
Methods All consecutive patients who were operated on by a RES under the supervision of a BCS at University Hospital Frankfurt/Main (UKF) for nodular goiter, Graves’ disease and T1/T2 differentiated thyroid carcinoma without proven or suspected lymph node metastasis in the lateral compartment between 2006 and 2014 were analyzed retrospectively after
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approval by the institutional review board (IRB No. 236/14). The study enrolment is shown in Fig. 1. Operations with an unclear operator assignment or a change in surgeons (e.g., one surgeon per side in TT), all operations that involved the transfer of individual operative steps from a BCS to a RES and cases with missing data were excluded. Patients with an intraoperative suspicion of lymph node metastasis in the lateral compartment, which led to a lateral lymphadenectomy, were also excluded. The exclusion criteria are listed in Table 1. When the operation was performed by a resident under the supervision of a BCS, it was classified into the resident (RES) group. RES between PGY 3 and 5 entered the training program after participating in thyroid operations in the role of Bfirst assistant^ for at least 1 year. During this year, the RESs were regularly handed over individual steps of the operation (access to the gland, wound closure, mobilization of the thyroid gland, vascular control, localization of the recurrent laryngeal nerve (RLN) and the parathyroid glands, intraoperative neurophysiological monitoring (IONM) and preparation of the RLN and/or the parathyroid glands). These operations were not the object of this study and were excluded. During the study period, three BCSs who were responsible for thyroid surgery training evaluated the ability of the RES to perform all of these steps safely and finally gave clearance to schedule the RES as the surgeon-in-charge. Operations of the RES that met the inclusion criteria after this clearance were included in the study. Operations with a BCS as the operatorin-charge that met the inclusion criteria were classified into the board-certified surgeon (BCS) group. The possible need for a change in surgeon due to complications during the operation was recorded in the digital operative protocol by the circulating nurse and analyzed retrospectively. The RES group was divided into patients who underwent a total thyroidectomy (TT), patients who underwent a subtotal/ near total thyroidectomy (ST) or patients who underwent a hemithyroidectomy (HT). Unplanned intraoperative changes and the postoperative need for TT due to the obligate intraoperative frozen section and final histological result were recorded. For optimized comparability, a matched-pair analysis was performed (Fig. 1). Every RES patient was linked to a BCS patient who received the same operation. The primary matching parameters were the weight of the specimen and the underlying thyroid disease, and the secondary parameters were BMI and non-thyroid diseases. Because overweight is correlated with an increase in operative time and morbidity, the body mass index (BMI) was registered for all patients [11]. Patient data, including preoperative ultrasound findings, operation protocols and histopathological findings, including specimen weight, were extracted from the electronic patient file. All specimens were examined for accidentally removed
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241
Fig. 1 Retrospective study enrolment of patients undergoing thyroid surgery and matched-pair design between operations performed by surgical resident (RES) and board-certified surgeons (BCS)
Assessed for eligibility n=869
OP by BCS due to insurance status n=156
Enrollment n=472
• • • • • • •
Excluded n=397 advanced carcinoma n=123 missing data n=74 re-operave surgery n=49 toxic goiter n=39 alternave diagnosis n=73 retrosternal goiter n=16 other n=23
OP by RES n=112
OP by BCS n=360
Total Thyroidectomy n=107
Total Thyroidectomy n=28
Hemithyroidectomy n=143
Hemithyroidectomy n=44
Subtotal Thyroidectomy n=110
Subtotal Thyroidectomy n=40 1. 2. 3. 4.
matching criteria specimen weight underlying thyroid disease BMI concomitant diseases
Total Thyroidectomy n=28
Total Thyroidectomy n=28
Hemithyroidectomy n=44
Hemithyroidectomy n=44
Subtotal Thyroidectomy n=40
Subtotal Thyroidectomy n=40
parathyroid glands by the pathologist. IONM was used in every patient for the identification of the RLN. If a loss of the IONM-electromyographic signal (LOS) occurred during the operation, the planned contralateral resection had to be abandoned. Preoperative and postoperative laryngoscopic evaluation of the vocal cord’s function was conducted in every patient by a board-certified otolaryngologist. The parameters related to the course of the operation included the operative time; intraoperative complications; and the localization, description and protection of the parathyroid
glands and the RLN. During the study period, all thyroid surgeries were conducted using a standardized set of surgical equipment, including an energy device for dissection (Ultracision or Harmonic/Harmonic ACE, Ethicon). The postoperative outcome parameters were symptomatic and asymptomatic hypocalcaemia (serum calcium below 2.19 mmol/l, persisting or transient), palsy of the RLN (transient or persisting), haemorrhage, infections, other complications, length of stay, return to the operation room (OR) and readmissions. Symptomatic hypocalcaemia was defined as
242 Table 1
Langenbecks Arch Surg (2016) 401:239–247 Exclusion criteria No. (n = 397)
Advanced carcinoma
123
• Undifferentiated thyroid carcinoma • Medullary thyroid carcinoma • Differentiated thyroid carcinoma > T1 • Differentiated thyroid carcinoma N+ in lateral compartment • Thyroid metastasis Missing data Re-operative thyroid surgery
74 49
Toxic goiter Alternative diagnosis (e.g., combination with parathyroidectomy) Retrosternal goiter Others
39 73 16 23
• Goiter impressing trachea or oesophagus • Thyrotoxic crisis/thyroid storm • Thyroiditis other than grave’s disease • Change of surgeon by organizational needs
paresthaesia, tickling or seizures combined with a serum calcium below 2.19 mmol/l and the disappearance of the symptoms after calcium substitution. All patients with RLN palsy were treated by a speech therapist for 3 months and subsequently reevaluated via laryngoscopy. Patients with postoperative hypocalcaemia or RLN palsy were followed up in our outpatient clinic.
criteria. The RES group was subdivided according to the executed procedure. Forty-four patients received a hemithyroidectomy (HT), and 40 patients received a subtotal thyroidectomy (Dunhill operation, ST) with remnant thyroid tissue below 2 ml at the upper thyroid pole. The remaining 28 patients received a total thyroidectomy (TT). Patient demographics, the preoperative ultrasound volume assessment of the thyroid, comorbidities and anticoagulant treatment did not differ significantly within the study population or the subgroups (Table 2). The postoperative specimen weight, BMI and underlying thyroid disease were matching criteria and therefore did not differ between RES and BCS patients (Table 3). Three of 15 BCSs who performed thyroid operations in the same period were responsible for assisting and supervising RES operations. After joining thyroid operations in the role of first assistant and the approval by the responsible BCS, seven PGY 3, nine PGY 4 and three PGY 5 RESs performed their first thyroid operation as surgeon-in-charge. Organizational matters (rotation to the outpatient clinic or intensive care unit and research) caused time differences in entering the training program. On average, 5.3 thyroid operations were performed by the RES during the study period, restricted to operations that met the inclusion criteria. Outcome and complications During the study period, intraoperative complications did not lead to the replacement of the operating RES. There was no need for the termination of an operation after LOS in either
Statistical analysis Statistical analysis was conducted using chi-square respectively Fisher’s exact test for categorical data and Mann–Whitneytest respectively Student’s t test for continuous data. SPSS software, version 23.0 (IBM SPSS Statistics®, Armonk, NY, USA), was used for statistical analysis. A p value of ≤0.05 was considered statistically significant.
Results Patient characteristics and surgical details A total of 864 thyroid operations were determined to be eligible. A total of 397 patients were excluded according to the criteria listed in Table 1, and 472 patients were included in the study. The insurance contracts of 156 patients demanded a BCS as surgeon-in-charge, so these patients were not eligible for surgical training but were used for matching. One hundred twelve patients who were operated by a RES under the surveillance of a BCS complied with the abovementioned
Table 2 Baseline demographic and clinical characteristics of the matched cohort RES (n = 112)
BCS (n = 112)
p value
Age (years), median Range Gender, female/male Thyroid disease • Benign goiter • Grave’s disease • Microcarcinoma Anticoagulant intake • ASS • Others
52 16.85–79.8 80:32
51 16.87–80.84 77:35
0.430
93 14 5
92 14 6
0.860 1.000 0.757
7 2
3 0
0.333
ECOG, median Range BMI (kg/m2), median Range
0 0–3 25.4 17.92–43.28
0 0–3 25.8 17.94–55.4
0.770
1.000 0.928
ECOG Eastern Cooperative Oncology Group, RES resident, BCS boardcertified surgeon, BMI body mass index
Langenbecks Arch Surg (2016) 401:239–247 Table 3 Thyroid measurements in the surgical resident (RES) and the board-certified surgeon (BCS) group
243
RES (n = 112)
BCS (n = 112)
p value
• Volumea (ml), mean (±SD)
21.5 (11.42)
21.56 (12.54)
0.998
Range • Specimen weight (g), mean (±SD)
5.8–48 16.58 (10.34)
3.8–48 16.59 (10.36)
0.999
5–44
5.2–44
32.35 (22.16)
29.90 (17.78)
0.617
9.7–120 34.75 (21.78)
8.4–79.5 35.89 (21.98)
0.860
5.6–93
6.5–93
45.03 (39.58)
38.63 (29.71)
0.533
7–214 51.59 (50.73)
6.2–130 50.62 (49.64)
0.944
7–214
6.9–211
Hemithyroidectomy
Range Subtotal thyroidectomy • Volumea (ml), mean (±SD) Range • Specimen weight (g), mean (±SD) Range Total thyroidectomy • Volumea (ml) mean (±SD) Range • Specimen weight (g), mean (±SD) Range SD standard deviation a
As estimated by preoperative ultrasound examination
group. Five patients were re-operated for postoperative haemorrhage, including three patients who were operated on by an RES and two patients who were operated on by a BCS (p = 0.205). In each group, we observed three superficial and deep surgical site infections (SSI) (p = 1.000), which were all treated with wound opening, lavage and antibiotics without the need for general anaesthesia. One BCS patient was readmitted for the treatment of the SSI, and the other patients had a prolonged stay due to the SSI.
Quality indicators The rate of operations with documented failure to localize the parathyroid gland did not differ between RES and BCS and ranged from 0 % in the TT group to 7.5 % in the ST group. Insufficient documentation of localization was more common than failure of localization in all subgroups, although no significant difference was observed between RES and BCS patients. We observed a trend towards more deficient documentation in the RES group for HT (RES vs. BCS 18.2 vs. 4.6 %, p = 0.089). The rate of accidentally removed parathyroid glands and the rate of replanted parathyroid glands did not differ between the groups (max. n = 2 for TT in BCS and RES). The rate of symptomatic postoperative hypocalcaemia ranged from n = 1; 2.3 % (HT, RES) to n = 9; 32.1 % (TT, RES), and asymptomatic hypocalcaemia was observed in n = 4; 9.1 % (HT, BCS) to n = 8; 28.6 % (TT, BCS). However, no statistically significant differences in hypocalcaemia rates were observed between BCS and RES patients. Within the study population, we observed no
persisting hypocalcaemia after a follow-up period of 6 months (Table 4). There were 218 RLNs at risk (NAR) for an iatrogenic injury. Every RLN was localized and monitored via IONM before and after resection. The general rate of transient RLN palsy was 3.7 %. Although we observed no significant differences between RES and BCS patients, the rate of postoperative recurrent nerve palsy was slightly higher in the BCS group: six (2.8 %) in the RES group vs. ten (4.6 %) in the BCS group (p = 0.446; Table 5). No LOS led to the abortion of a planned bilateral procedure, and no bilateral palsy occurred in either group. During follow-up, nerve palsies resolved in all 16 patients. Two RES patients and three BCS patients received a TT after a papillary thyroid carcinoma was diagnosed by intraoperative frozen section (p = 1.000). No completion TT after final histopathological result was necessary in either group. Economic factors The surgical equipment used during the operation did not differ between BCS and RES operations. The operative time was analyzed in the subgroups due to the inherent lengthened operation time of bilateral resections. Although RES operations took longer than BCS operations, these differences did not reach significance (Fig. 2). The mean increase in operation time ranged from 4.6 min (HT) to 8.6 min (ST), with a maximum increase in the ST group of 5.4 % relative to the overall operation time. The median stay was 2 days (range 1–10) for patients who received a HT and 3 days (range 1–32) for patients who
244
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Table 4 Hypocalcaemia rates and handling of the parathyroid glands
RES (n = 112)
BCS (n = 112)
p value
Hemithyroidectomy n = 88 Parathyroid glands, n (%) • Failure of localization
1 (2.3)
2 (4.6)
1.000
• Localization not documented • Accidentally removed
8 (18.2) 0 (0)
2 (4.6) 1 (2.3)
0.089 1.000
• Autotransplantation
7 (15.9)
4 (9.1)
0.521
Hypocalcaemia, n (%) • Asymptomatic
5 (11.4)
4 (9.1)
1.000
1 (2.3)
4 (9.1)
0.360
0 (0)
0 (0)
1.000
• Failure of localization • Localization not documented
3 (7.5) 10 (25)
2 (5) 7 (17.5)
1.000 0.586
• Accidentally removed • Autotransplantation
2 (5) 6 (15)
0 (0) 9 (22.5)
0.494 0.568
5 (12.5) 7 (17.5) 0 (0)
8 (20) 8 (20) 0 (0)
0.546 1.000 1.000
0 (0)
0 (0)
1.000
1 (3.6) 2 (7.1) 9 (32.1)
3 (10.7) 2 (7.1) 7 (25)
0.611 1.000 0.768
• Symptomatic • Persisting Subtotal thyroidectomy n = 80
Parathyroid glands, n (%)
Hypocalcaemia, n (%) • Asymptomatic • Symptomatic • Persisting Total thyroidectomy n = 56 Parathyroid glands, n (%) • Failure of localization • Localization not documented • Accidentally removed • Autotransplantation Hypocalcaemia, n (%) • Asymptomatic • Symptomatic • Persisting
5 (17.9)
8 (28.6)
0.528
9 (32.1) 0 (0)
6 (21.4) 0 (0)
0.547 1.000
RES resident, BCS board-certified surgeon
received a TT or ST; the length of stay did not differ significantly between RES and BCS patients (TT p = 0.80, ST p = 0.81, HT p = 0.471). Sufficient pain control, stable serum calcium, stable haemoglobin, uneventful remobilization and inconspicuous ventilation were obligate criteria for discharge. An extensive prolonged stay of over 5 days was caused by hypocalcaemia in six (5.4 %) RES and four (3.6 %) BCS
patients and by comorbidities in three (2.7 %) RES and two (1.8 %) BCS patients. SSI caused a stay of over 5 days in one (0.9 %) BCS patient, and one (0.9 %) RES patient and one BCS patient stayed for more than 5 days due to high drain volumes.
Discussion Table 5 The impact of thyroid operations performed by residents (RES) or board-certified surgeons (BCS) on the recurrent laryngeal nerves
Nerves at risk, n Palsy, n (%) Persisting paresis, n (%)
RES
BCS
p value
218 6 (2.8) 0
218 10 (4.6) 0
0.446 1.000
This study reveals for the first time that thyroid surgery can be taught to residents without impairing patient safety and without increasing costs due to longer operative times or hospital stays. In contrast to other studies that addressed the issue of resident participation, all residents performed the procedure from the beginning to the end, and selection bias regarding the patients was minimized by using a matched-pair analysis, which is a striking advantage of this study.
Langenbecks Arch Surg (2016) 401:239–247 325
p=0.654
p=0.317
300 275
p=0.486
250 Operative time [min]
Fig. 2 Comparison of operative times between surgical resident (RES) and board-certified surgeons (BCS) stratified to subtotal thyroidectomy (ST), hemithyroidectomy (HT), and total thyroidectomy (TT)
245
225 200 145.5
175 139.75
150 125
105.75
139.75 127.75
95.75
100 75 50
Resident participation in surgery, especially during the surgical training and education of surgeons-to-be, has become a crucial topic in recent years. The main aspects of this controversial debate are educational concepts, patient safety and economic factors. The rules, requirements and content of surgical education are controlled by national surgical societies or federal states and are usually legitimized by national authorities. In most countries, as in Germany, France, the UK and the USA, surgical training incorporates a curriculum of operations that the surgeon-to-be must perform to gain his board certification. Thyroidectomy has a medium difficulty level, and current German regulations on surgical education require the execution of this operation by trainees in general surgery, visceral surgery and paediatric surgery in all German federal states [9]. Comparable curricula are requested in the USA [10]. Different aspects led us to choose thyroid surgery to monitor our educational program. First, this multistep procedure offers the opportunity to analyze intraoperative quality (i.e., the localization and protection of the RLN and the parathyroid glands). Furthermore, several factors related to postoperative morbidity can be linked to surgical quality and thereby help in monitoring patient safety. In addition, the operative variance is limited, so the operative time is comparable between trainees and certified surgeons. The majority of studies that examined resident involvement did not define the terms Binvolvement^ or Bparticipation.^ Schreckenbach analyzed only procedures that were performed completely by the resident under the guidance and supervision of a BCS [8]. The other end of the spectrum is marked by Relles, who investigated resident involvement in pancreatic surgery. In that study, the resident’s role was that of a first assistant [5]. Studies that investigate the topic of education
by analyzing the NSQIP database usually give no further information about the role of the resident [12]. Because surgical training should enable the surgeon-to-be to execute operations completely and with full responsibility, our training concept gives the trainee the opportunity to perform all operative steps himself and determine the tactical aspects of the operation. The BCS supervises and guides the resident and ensures the patient’s security. For the purpose of this study, we analyzed only operations that were executed in accordance with this concept. The transfer of individual operative steps from the BCS to the resident during an operation executed by the BCS is commonly used for educational purposes in our hospital. These operations are not the object of this study, as the aspects of operative quality, operative time, morbidity and safety cannot be analyzed and compared clearly. Patient safety is of crucial importance, especially in an educational setting. There are no legal regulations related to resident participation or the need for the patient’s informed consent for resident participation. Thus, hospitals with a surgical training program need data about the effects of the training of surgeons-to-be on patient care. To our knowledge, no study investigated surgical quality parameters beyond the analysis of complications, morbidity and mortality. We regarded the localization and protection of the parathyroid glands and the RLN and the precise documentation of these steps as parameters that determine surgical quality. From this point of view, resident participation does not imply a decrease in surgical quality. Different factors influence the rate of RLN palsy, as reviewed by Hayward and colleagues; two of these factors are the caseload and experience of the surgeon [13]. While Dralle and his group found increased rates of RLN palsy
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among surgeons who performed less than 45 thyroidectomies a year in a large retrospective dataset, a prospective study published by Thomush refuted these findings [14, 15]. Shaha and Jaffe examined the impact of resident participation on this issue. However, their findings in 200 consecutive patients cannot be transferred to the actual situation due to significant differences in surgical approach [16]. We report transient palsy of the RLN in 3.7 % of the study population, which is consistent with the published data. Interestingly, although the difference did not reach statistical significance, the rate of palsies was lower in the RES group. Regarding postoperative hypocalcaemia, we observed transient hypocalcaemia rates that ranged from 2.3 to 32.1 %. This finding is similar to data reported in a systematic metaanalysis by Cheng, who reported transient hypocalcaemia rates that ranged from 0 to 3.1 to 44 % [17]. More importantly, we observed no differences between RES and BCS in the rates of either symptomatic or asymptomatic transient hypocalcaemia. Of note, we found no significant differences in the localization and handling of the parathyroid glands, but we noticed a trend towards less accurate documentation for HT in the RES group. The insufficient documentation in the RES group could be a sign of the lower awareness of the trainees about postoperative hypocalcaemia after HT. To improve the documentation of the parathyroid glands in the operative report and increase awareness of hypocalcaemia in the RES group, the BCS should sensitize the trainees to that topic and control the documentation in the operative reports. Concerning general morbidity and complications, the available data are contradictory. Even studies that used the NSQIP database provided diverse results. Davies’ database analysis revealed increased morbidity in cases of resident participation for several procedures in general surgery [3]. A counterexample can also be found. Ross and coworkers also performed a NSQIP database analysis and found no increase in complications for a typical general surgery procedure with a medium level of difficulty [18]. Studies that specified the degree of resident participation as operating surgeon did not show an increase in complications; neither Schreckenbach’s analysis of proctologic operations nor data published by Fanous and Carlin concerning bariatric operations revealed an increase in complications [8, 19]. This outcome is consistent with our findings. Through the use of a matched-pair analysis, the restriction of the included patients to those for whom residents acted as the operating surgeon and the large quantity of parameters analyzed in this study, we were able to demonstrate that resident participation did not imply an increased risk for the patient. This conclusion includes shortterm effects, such as infections or bleeding, as well as longterm effects, such as hypocalcaemia or palsy of the RLN. The increased operative time is attributed to the time spent teaching intraoperatively or to the residents being technically slower [20]. In our hospital, residents scheduled for thyroid
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operations were at an advanced level of training and had demonstrated technical skills on multiple occasions as the first assistant in complex procedures and the executing surgeon in more basic procedures. Furthermore, our teaching concept includes the execution of individual steps of a complex procedure by the resident as first assistant (for example, the mobilization of the thyroid gland, the localization of the parathyroid glands or the mobilization and IONM of the RLN). A study performed by Zendeja and colleagues underlined the importance of a structured teaching concept in a prospective, randomized study for laparoscopic inguinal hernia repair. This learning program included theoretical training, a multiplechoice test and virtual laparoscopic training. Trainees who joined such a training program had shorter operation times and lower complication rates [21]. Although simulationbased training programs are desirable and should be implemented in surgical training as often as possible, these concepts are expensive, time-consuming (problem of in-duty education) and unfortunately not available for each operative procedure. Thyroid surgery cannot be considered to be a basic or simple procedure due to the complexity of the operative steps, the dimensions of the structures of interest and the implications of the possible complications. Ross and colleagues observed changes in operative time with increased PGY level for laparoscopic hernia repair [18]. We could not verify these findings due to the homogeneity of the training levels of the residents in this study and the ambiguous documentation of the qualification level. The determination of a fixed PGY level for the start of training was not possible because the residents choose different periods for hospital changes or rotations. In our cohort, RES operations took slightly longer than operations performed solely by a BCS. However, the increase in the operative time was not significant and did not exceed 10 min in either of the subgroups. We consider this increase to be economically justifiable in the context of surgical training at a university hospital. Jolly examined the effect of resident participation in basic and advanced laparoscopic surgery and demonstrated an increase in the length of stay, especially for more complex procedures [22]. However, that study suffers from the limitations of most American College of Surgeons NSQIP database analyses, as it offers no information about the degree of resident involvement. In our study, the length of stay was not influenced by resident participation. Furthermore, the readmission rate and the need for return to the OR did not differ. Thus, beyond the abovementioned safety and quality aspects, the takeover of the operation by a resident was not a significant economic burden in our sample. The limitations of this study are its retrospective setting and the small sample size in comparison to studies that use the NSQIP database. On the other hand, the matched-pair design allows us to draw conclusions with a relatively low error caused by confounding variables. The analyzed parameters,
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such as RLN palsy, hypocalcaemia, bleeding and infections, are surrogate parameters of surgical quality, but these parameters have also been used by multiple authors. The strength of the study is that the analyzed procedures were conducted by residents from the beginning to the end, representing resident participation in its most extensive dimension. In conclusion, our data showed that thyroid surgery can be performed safely by RES under the supervision of BCS. Specifically, we observed no significant increases in operation time, complication rates and the length of hospital stay. Authors’ contributions Study conception and design: Alexander Reinisch and Nils Habbe Acquisition of data: Alexander Reinisch, Patrizia Malkomes and Katharina Holzer Analysis and interpretation of data: Alexander Reinisch, Juliane Liese and Nils Habbe Drafting of manuscript: Alexander Reinisch Critical revision of manuscript: Nils Habbe, Juliane Liese, Wolf Otto Bechstein, Teresa Schreckenbach and Juliane Liese
247 7.
8.
9.
10.
11.
12.
Compliance with ethical standards This study was not funded. Conflicts of interest The authors declare that they have no conflicts of interest. Ethical approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was approved by the local ethical committee of Frankfurt University (IRB No. 236/14).
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15.
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Porta CR, Sebesta JA, Brown TA, Steele SR, Martin MJ (2012) Training surgeons and the informed consent process: routine disclosure of trainee participation and its effect on patient willingness and consent rates. Arch Surg 147:57–62 2. Kasotakis G, Lakha A, Sarkar B, Kunitake H, Kissane-Lee N, Dechert T, McAneny D, Burke P, Doherty G (2014) Trainee participation is associated with adverse outcomes in emergency general surgery: an analysis of the National Surgical Quality Improvement Program database. Ann Surg 260:483–490 3. Davis SS, Husain FA, Lin E, Nandipati KC, Perez S, Sweeney JF (2013) Resident participation in index laparoscopic general surgical cases: impact of the learning environment on surgical outcomes. J Am Coll Surg 216:96–104 4. Sakran JV, Hoffman RL, Ko C, Kelz RR (2013) The ACS NSQIP quality in-training initiative: educating residents to ensure the future of optimal surgical care. Bull Am Coll Surg 98:30–35 5. Relles DM, Burkhart RA, Pucci MJ, Sendecki J, Tholey R, Drueding R, Sauter PK, Kennedy EP, Winter JM, Lavu H, Yeo CJ (2014) Does resident experience affect outcomes in complex abdominal surgery? Pancreaticoduodenectomy as an example. J Gastrointest Surg 18:279–285 6. Hernández-Irizarry R, Zendejas B, Ali SM, Lohse CM, Farley DR (2012) Impact of resident participation on laparoscopic inguinal hernia repairs: are residents slowing us down? J Surg Educ 69: 746–752. doi:10.1016/j.jsurg.2012.08.013
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de Santibañes M, Alvarez FA, Sieling E, Vaccarezza H, de Santibañes E, Vaccaro CA (2015) Postoperative complications at a university hospital: is there a difference between patients operated by supervised residents vs. trained surgeons? Langenbeck’s Arch Surg 400:77–82. doi:10.1007/s00423-014-1261-z Schreckenbach T, El Yourouri H, Bechstein EO, Habbe N (2015) Proctologic surgery done by residents—complications pre-programmed? J Visc Surg. doi:10.1016/j.jviscsurg.2015.11.013 (Muster) Weiterbildungsordung der Bundesärztekammer von 2003 mit den Erweiterungen und Ergänzungen 2013 [(Model) Specialty Training Regulations 2003 as amended on 28/06/2013]; (Model) Specialty Training Regulations 2003 as amended on 28/06/2013. http://www.bundesaerztekammer.de/fileadmin/user_upload/ downloads/MWBO_Englisch_210113_FINFI_aktualisiert171214. pdf. Accessed 12 Jan 2016 The American Board of Surgery; Training and Certification http:// www.absurgery.org/xfer/curriculumoutline2014-15.pdf. Accessed 12 Jan 2016 Buerba R, Roman SA, Sosa JA (2011) Thyroidectomy and parathyroidectomy in patients with high body mass index are safe overall: analysis of 26,864 patients. Surgery 150:950–958. doi:10.1016/ j.surg.2011.02.017 Ejaz A, Spolverato G, Kim Y, Wolfgang CL, Hirose K, Weiss M, Makary MA, Pawlik TM (2015) The impact of resident involvement on surgical outcomes among patients undergoing hepatic and pancreatic resections. Surgery 158:323–330. doi:10.1016/j.surg. 2015.01.027 Hayward NJ, Grodski S, Yeung M, Johnson WR, Serpell J (2013) Recurrent laryngeal nerve injury in thyroid surgery: a review. ANZ J Surg 83:15–21. doi:10.1111/j.1445-2197.2012.06247.x Dralle H, Sekulla C, Haerting J, Timmermann W, Neumann HJ, Kruse E, Grond S, Mühlig HP, Richter C, Voss J, Thomusch O, Lippert H, Gastinger I, Brauckhoff M, Gimm O (2004) Risk factors of paralysis and functional outcome after recurrent laryngeal nerve monitoring in thyroid surgery. Surgery 136:1310–1322 Thomusch O, Machens A, Sekulla C, Ukkat J, Lippert H, Gastinger I, Dralle H (2000) Multivariate analysis of risk factors for postoperative complications in benign goiter surgery: prospective multicenter study in Germany. World J Surg 24:1335–1341 Shaha A, Jaffe BM (1988) Complications of thyroid surgery performed by residents. Surgery 104:1109–1114 Cheng H, Soleas I, Ferko NC, Clymer JW, Amaral JF (2015) A systematic review and meta-analysis of harmonic focus in thyroidectomy compared to conventional techniques. Thyroid Res 8:15. doi:10.1186/s13044-015-0027-1 Ross SW, Oommen B, Kim M, Walters AL, Green JM, Heniford BT, Augenstein VA (2014) A little slower, but just as good: postgraduate year resident versus attending outcomes in laparoscopic ventral hernia repair. Surg Endosc 28:3092–3100. doi:10.1007/ s00464-014-3586-7 Fanous M, Carlin A (2012) Surgical resident participation in laparoscopic Roux-en-Y bypass: is it safe? Surgery 152:21–25. doi:10. 1016/j.surg.2012.02.014 Uecker J, Luftman K, Ali S, Brown C (2013) Comparable operative times with and without surgery resident participation. J Surg Educ 70:696–699. doi:10.1016/j.jsurg.2013.06.011 Zendejas B, Cook DA, Bingener J, Huebner M, Dunn WF, Sarr MG, Farley DR (2011) Simulation-based mastery learning improves patient outcomes in laparoscopic inguinal hernia repair: a randomized controlled trial. Ann Surg 254:502–509. doi:10.1097/ SLA.0b013e31822c6994 Jolley J, Lomelin D, Simorov A, Tadaki C, Oleynikov D (2015) Resident involvement in laparoscopic procedures does not worsen clinical outcomes but may increase operative times and length of hospital stay. Surg Endosc
ORIGINAL ARTICLE
Education in thyroid surgery: a matched-pair analysis comparing residents and board-certified surgeons Alexander Reinisch 1 & Patrizia Malkomes 1 & Juliane Liese 1 & Teresa Schreckenbach 1 & Katharina Holzer 1 & Wolf Otto Bechstein 1 & Nils Habbe 1
Received: 14 January 2016 / Accepted: 23 February 2016 / Published online: 1 March 2016 # Springer-Verlag Berlin Heidelberg 2016
Abstract Purpose Resident participation in operative procedures is mandatory in educational residency programs but remains controversial, especially in the context of patient safety. This study compared the surgical quality and outcomes of thyroidectomies performed by surgical residents (RESs) and boardcertified surgeons (BCSs). Methods This retrospective matched-pair study included patients undergoing thyroidectomies for multinodular goiter, Grave’s disease and early-stage thyroid cancer that were performed by a RES with BCS supervision between 2006 and 2014. The intraoperative and postoperative course, complication rates and handling of the recurrent laryngeal nerve (RLN) and parathyroid glands were analyzed. Results In total, 112 thyroidectomies that were performed by a RES fulfilled the inclusion criteria and were matched 1:1 with BCS patients. We included 88 hemithyroidectomies, 80 subtotal thyroidectomies and 56 total thyroidectomies. No significant differences in the handling of the RLN or parathyroid glands, the rates of postoperative RLN palsies or the rates of hypocalcaemia were found. No intraoperative complications led to the replacement of the RES as the surgeon-incharge. Three RES and two BCS patients experienced postoperative haemorrhages (p = 0.205), and three surgical site infections (p = 1.000) occurred in each group. The mean
* Alexander Reinisch [email protected]
1
Department of General and Visceral Surgery, Johann Wolfgang Goethe University Hospital, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
operative time and the length of stay did not differ significantly between the two groups. Conclusions Major aspects of patient safety in thyroid surgery are not affected by resident participation. Thyroidectomies performed by RES are not significantly longer and reveal no differences in length of stay or complication rates. The economic burden of resident involvement is modest. Keywords Surgical education . Thyroid . Patient safety . Resident involvement . Resident participation
Introduction In addition to the acquisition of theoretical knowledge, the development of practical skills is an important aspect of surgical training. In most countries, the teaching of practical skills is achieved through the involvement of the surgeon-to-be in surgical procedures. Starting as an assistant during interventions with increasing complexity, the trainee will eventually perform operations by himself. These operations will usually be guided, instructed and supervised by a board-certified surgeon (BCS) and will also become more complex during the residency period. Several topics regarding teaching in the operation room (OR) are of particular importance. First, the trainee, the BCS and the patient are in an area of conflicting interests. The trainee must fulfil a curriculum of guided operations and gain technical experience, while the BCS must maintain patient safety, ensure the success of the procedure and consider economic factors. For the patient, the vitally important factor is the success of his treatment and the avoidance of complications. In fact, patients are often concerned about resident participation, and the need for informed consent for resident participation is under discussion [1]. To date, no specific legal
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requirements for resident participation exist in Germany, the USA or the UK. Furthermore, the term Bresident participation^ must be clarified. In studies based on data from the National Surgical Quality Improvement Program (NSQIP), the degree of resident participation remains unclear [2–4]. In addition, most NSQIP-based studies analyzed a combination of different operations. Other studies defined resident participation as the resident acting as first assistant during the operation, for example in Relles’ analysis of residents in pancreatic surgery [5]). Data related to operations performed by residents under the supervision of and with occasional help from the BCS are rare. Several studies demonstrated that resident involvement caused increased operation time [2, 6]. The impacts of surgical resident (RES) on complication rates and outcomes are controversial [2, 6, 7]. Of note, operation time and complication rates are crucial economic factors. Recent publications revealed no differences in surgical quality. Schreckenbach revealed no increases in complication and recurrence rates in proctologic operations, which were often performed by RES of a lower postgraduate year (PGY) [8]. Thyroid operations are an ideal advanced training operation. As a part of the curriculum for general surgery in most countries [9, 10], thyroid surgery necessitates a high-quality surgery because complications could have major implications. Difficile preparation, the localization and protection of smallsized structures and the tactical planning and realization of a multi-step operation are special requirements of the RES in thyroid surgery. On the other hand, the clear sequence of operative steps and the possibility of observing and accessing every region of the operating field allow the supervising BCS to maintain a high degree of control over the operation. In contrast to open abdominal operations, in thyroid surgery, the field of vision is almost identical for both the BCS and the RES. The BCS is not hindered in his ability to intervene by holding organs or providing access to special regions of the situs. Thus, the BCS may ensure patient safety and the success of the operation more easily than in open abdominal surgery. The aim of this study was to investigate the impact of resident participation on the quality of thyroid operations and postoperative complication rates.
Methods All consecutive patients who were operated on by a RES under the supervision of a BCS at University Hospital Frankfurt/Main (UKF) for nodular goiter, Graves’ disease and T1/T2 differentiated thyroid carcinoma without proven or suspected lymph node metastasis in the lateral compartment between 2006 and 2014 were analyzed retrospectively after
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approval by the institutional review board (IRB No. 236/14). The study enrolment is shown in Fig. 1. Operations with an unclear operator assignment or a change in surgeons (e.g., one surgeon per side in TT), all operations that involved the transfer of individual operative steps from a BCS to a RES and cases with missing data were excluded. Patients with an intraoperative suspicion of lymph node metastasis in the lateral compartment, which led to a lateral lymphadenectomy, were also excluded. The exclusion criteria are listed in Table 1. When the operation was performed by a resident under the supervision of a BCS, it was classified into the resident (RES) group. RES between PGY 3 and 5 entered the training program after participating in thyroid operations in the role of Bfirst assistant^ for at least 1 year. During this year, the RESs were regularly handed over individual steps of the operation (access to the gland, wound closure, mobilization of the thyroid gland, vascular control, localization of the recurrent laryngeal nerve (RLN) and the parathyroid glands, intraoperative neurophysiological monitoring (IONM) and preparation of the RLN and/or the parathyroid glands). These operations were not the object of this study and were excluded. During the study period, three BCSs who were responsible for thyroid surgery training evaluated the ability of the RES to perform all of these steps safely and finally gave clearance to schedule the RES as the surgeon-in-charge. Operations of the RES that met the inclusion criteria after this clearance were included in the study. Operations with a BCS as the operatorin-charge that met the inclusion criteria were classified into the board-certified surgeon (BCS) group. The possible need for a change in surgeon due to complications during the operation was recorded in the digital operative protocol by the circulating nurse and analyzed retrospectively. The RES group was divided into patients who underwent a total thyroidectomy (TT), patients who underwent a subtotal/ near total thyroidectomy (ST) or patients who underwent a hemithyroidectomy (HT). Unplanned intraoperative changes and the postoperative need for TT due to the obligate intraoperative frozen section and final histological result were recorded. For optimized comparability, a matched-pair analysis was performed (Fig. 1). Every RES patient was linked to a BCS patient who received the same operation. The primary matching parameters were the weight of the specimen and the underlying thyroid disease, and the secondary parameters were BMI and non-thyroid diseases. Because overweight is correlated with an increase in operative time and morbidity, the body mass index (BMI) was registered for all patients [11]. Patient data, including preoperative ultrasound findings, operation protocols and histopathological findings, including specimen weight, were extracted from the electronic patient file. All specimens were examined for accidentally removed
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241
Fig. 1 Retrospective study enrolment of patients undergoing thyroid surgery and matched-pair design between operations performed by surgical resident (RES) and board-certified surgeons (BCS)
Assessed for eligibility n=869
OP by BCS due to insurance status n=156
Enrollment n=472
• • • • • • •
Excluded n=397 advanced carcinoma n=123 missing data n=74 re-operave surgery n=49 toxic goiter n=39 alternave diagnosis n=73 retrosternal goiter n=16 other n=23
OP by RES n=112
OP by BCS n=360
Total Thyroidectomy n=107
Total Thyroidectomy n=28
Hemithyroidectomy n=143
Hemithyroidectomy n=44
Subtotal Thyroidectomy n=110
Subtotal Thyroidectomy n=40 1. 2. 3. 4.
matching criteria specimen weight underlying thyroid disease BMI concomitant diseases
Total Thyroidectomy n=28
Total Thyroidectomy n=28
Hemithyroidectomy n=44
Hemithyroidectomy n=44
Subtotal Thyroidectomy n=40
Subtotal Thyroidectomy n=40
parathyroid glands by the pathologist. IONM was used in every patient for the identification of the RLN. If a loss of the IONM-electromyographic signal (LOS) occurred during the operation, the planned contralateral resection had to be abandoned. Preoperative and postoperative laryngoscopic evaluation of the vocal cord’s function was conducted in every patient by a board-certified otolaryngologist. The parameters related to the course of the operation included the operative time; intraoperative complications; and the localization, description and protection of the parathyroid
glands and the RLN. During the study period, all thyroid surgeries were conducted using a standardized set of surgical equipment, including an energy device for dissection (Ultracision or Harmonic/Harmonic ACE, Ethicon). The postoperative outcome parameters were symptomatic and asymptomatic hypocalcaemia (serum calcium below 2.19 mmol/l, persisting or transient), palsy of the RLN (transient or persisting), haemorrhage, infections, other complications, length of stay, return to the operation room (OR) and readmissions. Symptomatic hypocalcaemia was defined as
242 Table 1
Langenbecks Arch Surg (2016) 401:239–247 Exclusion criteria No. (n = 397)
Advanced carcinoma
123
• Undifferentiated thyroid carcinoma • Medullary thyroid carcinoma • Differentiated thyroid carcinoma > T1 • Differentiated thyroid carcinoma N+ in lateral compartment • Thyroid metastasis Missing data Re-operative thyroid surgery
74 49
Toxic goiter Alternative diagnosis (e.g., combination with parathyroidectomy) Retrosternal goiter Others
39 73 16 23
• Goiter impressing trachea or oesophagus • Thyrotoxic crisis/thyroid storm • Thyroiditis other than grave’s disease • Change of surgeon by organizational needs
paresthaesia, tickling or seizures combined with a serum calcium below 2.19 mmol/l and the disappearance of the symptoms after calcium substitution. All patients with RLN palsy were treated by a speech therapist for 3 months and subsequently reevaluated via laryngoscopy. Patients with postoperative hypocalcaemia or RLN palsy were followed up in our outpatient clinic.
criteria. The RES group was subdivided according to the executed procedure. Forty-four patients received a hemithyroidectomy (HT), and 40 patients received a subtotal thyroidectomy (Dunhill operation, ST) with remnant thyroid tissue below 2 ml at the upper thyroid pole. The remaining 28 patients received a total thyroidectomy (TT). Patient demographics, the preoperative ultrasound volume assessment of the thyroid, comorbidities and anticoagulant treatment did not differ significantly within the study population or the subgroups (Table 2). The postoperative specimen weight, BMI and underlying thyroid disease were matching criteria and therefore did not differ between RES and BCS patients (Table 3). Three of 15 BCSs who performed thyroid operations in the same period were responsible for assisting and supervising RES operations. After joining thyroid operations in the role of first assistant and the approval by the responsible BCS, seven PGY 3, nine PGY 4 and three PGY 5 RESs performed their first thyroid operation as surgeon-in-charge. Organizational matters (rotation to the outpatient clinic or intensive care unit and research) caused time differences in entering the training program. On average, 5.3 thyroid operations were performed by the RES during the study period, restricted to operations that met the inclusion criteria. Outcome and complications During the study period, intraoperative complications did not lead to the replacement of the operating RES. There was no need for the termination of an operation after LOS in either
Statistical analysis Statistical analysis was conducted using chi-square respectively Fisher’s exact test for categorical data and Mann–Whitneytest respectively Student’s t test for continuous data. SPSS software, version 23.0 (IBM SPSS Statistics®, Armonk, NY, USA), was used for statistical analysis. A p value of ≤0.05 was considered statistically significant.
Results Patient characteristics and surgical details A total of 864 thyroid operations were determined to be eligible. A total of 397 patients were excluded according to the criteria listed in Table 1, and 472 patients were included in the study. The insurance contracts of 156 patients demanded a BCS as surgeon-in-charge, so these patients were not eligible for surgical training but were used for matching. One hundred twelve patients who were operated by a RES under the surveillance of a BCS complied with the abovementioned
Table 2 Baseline demographic and clinical characteristics of the matched cohort RES (n = 112)
BCS (n = 112)
p value
Age (years), median Range Gender, female/male Thyroid disease • Benign goiter • Grave’s disease • Microcarcinoma Anticoagulant intake • ASS • Others
52 16.85–79.8 80:32
51 16.87–80.84 77:35
0.430
93 14 5
92 14 6
0.860 1.000 0.757
7 2
3 0
0.333
ECOG, median Range BMI (kg/m2), median Range
0 0–3 25.4 17.92–43.28
0 0–3 25.8 17.94–55.4
0.770
1.000 0.928
ECOG Eastern Cooperative Oncology Group, RES resident, BCS boardcertified surgeon, BMI body mass index
Langenbecks Arch Surg (2016) 401:239–247 Table 3 Thyroid measurements in the surgical resident (RES) and the board-certified surgeon (BCS) group
243
RES (n = 112)
BCS (n = 112)
p value
• Volumea (ml), mean (±SD)
21.5 (11.42)
21.56 (12.54)
0.998
Range • Specimen weight (g), mean (±SD)
5.8–48 16.58 (10.34)
3.8–48 16.59 (10.36)
0.999
5–44
5.2–44
32.35 (22.16)
29.90 (17.78)
0.617
9.7–120 34.75 (21.78)
8.4–79.5 35.89 (21.98)
0.860
5.6–93
6.5–93
45.03 (39.58)
38.63 (29.71)
0.533
7–214 51.59 (50.73)
6.2–130 50.62 (49.64)
0.944
7–214
6.9–211
Hemithyroidectomy
Range Subtotal thyroidectomy • Volumea (ml), mean (±SD) Range • Specimen weight (g), mean (±SD) Range Total thyroidectomy • Volumea (ml) mean (±SD) Range • Specimen weight (g), mean (±SD) Range SD standard deviation a
As estimated by preoperative ultrasound examination
group. Five patients were re-operated for postoperative haemorrhage, including three patients who were operated on by an RES and two patients who were operated on by a BCS (p = 0.205). In each group, we observed three superficial and deep surgical site infections (SSI) (p = 1.000), which were all treated with wound opening, lavage and antibiotics without the need for general anaesthesia. One BCS patient was readmitted for the treatment of the SSI, and the other patients had a prolonged stay due to the SSI.
Quality indicators The rate of operations with documented failure to localize the parathyroid gland did not differ between RES and BCS and ranged from 0 % in the TT group to 7.5 % in the ST group. Insufficient documentation of localization was more common than failure of localization in all subgroups, although no significant difference was observed between RES and BCS patients. We observed a trend towards more deficient documentation in the RES group for HT (RES vs. BCS 18.2 vs. 4.6 %, p = 0.089). The rate of accidentally removed parathyroid glands and the rate of replanted parathyroid glands did not differ between the groups (max. n = 2 for TT in BCS and RES). The rate of symptomatic postoperative hypocalcaemia ranged from n = 1; 2.3 % (HT, RES) to n = 9; 32.1 % (TT, RES), and asymptomatic hypocalcaemia was observed in n = 4; 9.1 % (HT, BCS) to n = 8; 28.6 % (TT, BCS). However, no statistically significant differences in hypocalcaemia rates were observed between BCS and RES patients. Within the study population, we observed no
persisting hypocalcaemia after a follow-up period of 6 months (Table 4). There were 218 RLNs at risk (NAR) for an iatrogenic injury. Every RLN was localized and monitored via IONM before and after resection. The general rate of transient RLN palsy was 3.7 %. Although we observed no significant differences between RES and BCS patients, the rate of postoperative recurrent nerve palsy was slightly higher in the BCS group: six (2.8 %) in the RES group vs. ten (4.6 %) in the BCS group (p = 0.446; Table 5). No LOS led to the abortion of a planned bilateral procedure, and no bilateral palsy occurred in either group. During follow-up, nerve palsies resolved in all 16 patients. Two RES patients and three BCS patients received a TT after a papillary thyroid carcinoma was diagnosed by intraoperative frozen section (p = 1.000). No completion TT after final histopathological result was necessary in either group. Economic factors The surgical equipment used during the operation did not differ between BCS and RES operations. The operative time was analyzed in the subgroups due to the inherent lengthened operation time of bilateral resections. Although RES operations took longer than BCS operations, these differences did not reach significance (Fig. 2). The mean increase in operation time ranged from 4.6 min (HT) to 8.6 min (ST), with a maximum increase in the ST group of 5.4 % relative to the overall operation time. The median stay was 2 days (range 1–10) for patients who received a HT and 3 days (range 1–32) for patients who
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Table 4 Hypocalcaemia rates and handling of the parathyroid glands
RES (n = 112)
BCS (n = 112)
p value
Hemithyroidectomy n = 88 Parathyroid glands, n (%) • Failure of localization
1 (2.3)
2 (4.6)
1.000
• Localization not documented • Accidentally removed
8 (18.2) 0 (0)
2 (4.6) 1 (2.3)
0.089 1.000
• Autotransplantation
7 (15.9)
4 (9.1)
0.521
Hypocalcaemia, n (%) • Asymptomatic
5 (11.4)
4 (9.1)
1.000
1 (2.3)
4 (9.1)
0.360
0 (0)
0 (0)
1.000
• Failure of localization • Localization not documented
3 (7.5) 10 (25)
2 (5) 7 (17.5)
1.000 0.586
• Accidentally removed • Autotransplantation
2 (5) 6 (15)
0 (0) 9 (22.5)
0.494 0.568
5 (12.5) 7 (17.5) 0 (0)
8 (20) 8 (20) 0 (0)
0.546 1.000 1.000
0 (0)
0 (0)
1.000
1 (3.6) 2 (7.1) 9 (32.1)
3 (10.7) 2 (7.1) 7 (25)
0.611 1.000 0.768
• Symptomatic • Persisting Subtotal thyroidectomy n = 80
Parathyroid glands, n (%)
Hypocalcaemia, n (%) • Asymptomatic • Symptomatic • Persisting Total thyroidectomy n = 56 Parathyroid glands, n (%) • Failure of localization • Localization not documented • Accidentally removed • Autotransplantation Hypocalcaemia, n (%) • Asymptomatic • Symptomatic • Persisting
5 (17.9)
8 (28.6)
0.528
9 (32.1) 0 (0)
6 (21.4) 0 (0)
0.547 1.000
RES resident, BCS board-certified surgeon
received a TT or ST; the length of stay did not differ significantly between RES and BCS patients (TT p = 0.80, ST p = 0.81, HT p = 0.471). Sufficient pain control, stable serum calcium, stable haemoglobin, uneventful remobilization and inconspicuous ventilation were obligate criteria for discharge. An extensive prolonged stay of over 5 days was caused by hypocalcaemia in six (5.4 %) RES and four (3.6 %) BCS
patients and by comorbidities in three (2.7 %) RES and two (1.8 %) BCS patients. SSI caused a stay of over 5 days in one (0.9 %) BCS patient, and one (0.9 %) RES patient and one BCS patient stayed for more than 5 days due to high drain volumes.
Discussion Table 5 The impact of thyroid operations performed by residents (RES) or board-certified surgeons (BCS) on the recurrent laryngeal nerves
Nerves at risk, n Palsy, n (%) Persisting paresis, n (%)
RES
BCS
p value
218 6 (2.8) 0
218 10 (4.6) 0
0.446 1.000
This study reveals for the first time that thyroid surgery can be taught to residents without impairing patient safety and without increasing costs due to longer operative times or hospital stays. In contrast to other studies that addressed the issue of resident participation, all residents performed the procedure from the beginning to the end, and selection bias regarding the patients was minimized by using a matched-pair analysis, which is a striking advantage of this study.
Langenbecks Arch Surg (2016) 401:239–247 325
p=0.654
p=0.317
300 275
p=0.486
250 Operative time [min]
Fig. 2 Comparison of operative times between surgical resident (RES) and board-certified surgeons (BCS) stratified to subtotal thyroidectomy (ST), hemithyroidectomy (HT), and total thyroidectomy (TT)
245
225 200 145.5
175 139.75
150 125
105.75
139.75 127.75
95.75
100 75 50
Resident participation in surgery, especially during the surgical training and education of surgeons-to-be, has become a crucial topic in recent years. The main aspects of this controversial debate are educational concepts, patient safety and economic factors. The rules, requirements and content of surgical education are controlled by national surgical societies or federal states and are usually legitimized by national authorities. In most countries, as in Germany, France, the UK and the USA, surgical training incorporates a curriculum of operations that the surgeon-to-be must perform to gain his board certification. Thyroidectomy has a medium difficulty level, and current German regulations on surgical education require the execution of this operation by trainees in general surgery, visceral surgery and paediatric surgery in all German federal states [9]. Comparable curricula are requested in the USA [10]. Different aspects led us to choose thyroid surgery to monitor our educational program. First, this multistep procedure offers the opportunity to analyze intraoperative quality (i.e., the localization and protection of the RLN and the parathyroid glands). Furthermore, several factors related to postoperative morbidity can be linked to surgical quality and thereby help in monitoring patient safety. In addition, the operative variance is limited, so the operative time is comparable between trainees and certified surgeons. The majority of studies that examined resident involvement did not define the terms Binvolvement^ or Bparticipation.^ Schreckenbach analyzed only procedures that were performed completely by the resident under the guidance and supervision of a BCS [8]. The other end of the spectrum is marked by Relles, who investigated resident involvement in pancreatic surgery. In that study, the resident’s role was that of a first assistant [5]. Studies that investigate the topic of education
by analyzing the NSQIP database usually give no further information about the role of the resident [12]. Because surgical training should enable the surgeon-to-be to execute operations completely and with full responsibility, our training concept gives the trainee the opportunity to perform all operative steps himself and determine the tactical aspects of the operation. The BCS supervises and guides the resident and ensures the patient’s security. For the purpose of this study, we analyzed only operations that were executed in accordance with this concept. The transfer of individual operative steps from the BCS to the resident during an operation executed by the BCS is commonly used for educational purposes in our hospital. These operations are not the object of this study, as the aspects of operative quality, operative time, morbidity and safety cannot be analyzed and compared clearly. Patient safety is of crucial importance, especially in an educational setting. There are no legal regulations related to resident participation or the need for the patient’s informed consent for resident participation. Thus, hospitals with a surgical training program need data about the effects of the training of surgeons-to-be on patient care. To our knowledge, no study investigated surgical quality parameters beyond the analysis of complications, morbidity and mortality. We regarded the localization and protection of the parathyroid glands and the RLN and the precise documentation of these steps as parameters that determine surgical quality. From this point of view, resident participation does not imply a decrease in surgical quality. Different factors influence the rate of RLN palsy, as reviewed by Hayward and colleagues; two of these factors are the caseload and experience of the surgeon [13]. While Dralle and his group found increased rates of RLN palsy
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among surgeons who performed less than 45 thyroidectomies a year in a large retrospective dataset, a prospective study published by Thomush refuted these findings [14, 15]. Shaha and Jaffe examined the impact of resident participation on this issue. However, their findings in 200 consecutive patients cannot be transferred to the actual situation due to significant differences in surgical approach [16]. We report transient palsy of the RLN in 3.7 % of the study population, which is consistent with the published data. Interestingly, although the difference did not reach statistical significance, the rate of palsies was lower in the RES group. Regarding postoperative hypocalcaemia, we observed transient hypocalcaemia rates that ranged from 2.3 to 32.1 %. This finding is similar to data reported in a systematic metaanalysis by Cheng, who reported transient hypocalcaemia rates that ranged from 0 to 3.1 to 44 % [17]. More importantly, we observed no differences between RES and BCS in the rates of either symptomatic or asymptomatic transient hypocalcaemia. Of note, we found no significant differences in the localization and handling of the parathyroid glands, but we noticed a trend towards less accurate documentation for HT in the RES group. The insufficient documentation in the RES group could be a sign of the lower awareness of the trainees about postoperative hypocalcaemia after HT. To improve the documentation of the parathyroid glands in the operative report and increase awareness of hypocalcaemia in the RES group, the BCS should sensitize the trainees to that topic and control the documentation in the operative reports. Concerning general morbidity and complications, the available data are contradictory. Even studies that used the NSQIP database provided diverse results. Davies’ database analysis revealed increased morbidity in cases of resident participation for several procedures in general surgery [3]. A counterexample can also be found. Ross and coworkers also performed a NSQIP database analysis and found no increase in complications for a typical general surgery procedure with a medium level of difficulty [18]. Studies that specified the degree of resident participation as operating surgeon did not show an increase in complications; neither Schreckenbach’s analysis of proctologic operations nor data published by Fanous and Carlin concerning bariatric operations revealed an increase in complications [8, 19]. This outcome is consistent with our findings. Through the use of a matched-pair analysis, the restriction of the included patients to those for whom residents acted as the operating surgeon and the large quantity of parameters analyzed in this study, we were able to demonstrate that resident participation did not imply an increased risk for the patient. This conclusion includes shortterm effects, such as infections or bleeding, as well as longterm effects, such as hypocalcaemia or palsy of the RLN. The increased operative time is attributed to the time spent teaching intraoperatively or to the residents being technically slower [20]. In our hospital, residents scheduled for thyroid
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operations were at an advanced level of training and had demonstrated technical skills on multiple occasions as the first assistant in complex procedures and the executing surgeon in more basic procedures. Furthermore, our teaching concept includes the execution of individual steps of a complex procedure by the resident as first assistant (for example, the mobilization of the thyroid gland, the localization of the parathyroid glands or the mobilization and IONM of the RLN). A study performed by Zendeja and colleagues underlined the importance of a structured teaching concept in a prospective, randomized study for laparoscopic inguinal hernia repair. This learning program included theoretical training, a multiplechoice test and virtual laparoscopic training. Trainees who joined such a training program had shorter operation times and lower complication rates [21]. Although simulationbased training programs are desirable and should be implemented in surgical training as often as possible, these concepts are expensive, time-consuming (problem of in-duty education) and unfortunately not available for each operative procedure. Thyroid surgery cannot be considered to be a basic or simple procedure due to the complexity of the operative steps, the dimensions of the structures of interest and the implications of the possible complications. Ross and colleagues observed changes in operative time with increased PGY level for laparoscopic hernia repair [18]. We could not verify these findings due to the homogeneity of the training levels of the residents in this study and the ambiguous documentation of the qualification level. The determination of a fixed PGY level for the start of training was not possible because the residents choose different periods for hospital changes or rotations. In our cohort, RES operations took slightly longer than operations performed solely by a BCS. However, the increase in the operative time was not significant and did not exceed 10 min in either of the subgroups. We consider this increase to be economically justifiable in the context of surgical training at a university hospital. Jolly examined the effect of resident participation in basic and advanced laparoscopic surgery and demonstrated an increase in the length of stay, especially for more complex procedures [22]. However, that study suffers from the limitations of most American College of Surgeons NSQIP database analyses, as it offers no information about the degree of resident involvement. In our study, the length of stay was not influenced by resident participation. Furthermore, the readmission rate and the need for return to the OR did not differ. Thus, beyond the abovementioned safety and quality aspects, the takeover of the operation by a resident was not a significant economic burden in our sample. The limitations of this study are its retrospective setting and the small sample size in comparison to studies that use the NSQIP database. On the other hand, the matched-pair design allows us to draw conclusions with a relatively low error caused by confounding variables. The analyzed parameters,
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such as RLN palsy, hypocalcaemia, bleeding and infections, are surrogate parameters of surgical quality, but these parameters have also been used by multiple authors. The strength of the study is that the analyzed procedures were conducted by residents from the beginning to the end, representing resident participation in its most extensive dimension. In conclusion, our data showed that thyroid surgery can be performed safely by RES under the supervision of BCS. Specifically, we observed no significant increases in operation time, complication rates and the length of hospital stay. Authors’ contributions Study conception and design: Alexander Reinisch and Nils Habbe Acquisition of data: Alexander Reinisch, Patrizia Malkomes and Katharina Holzer Analysis and interpretation of data: Alexander Reinisch, Juliane Liese and Nils Habbe Drafting of manuscript: Alexander Reinisch Critical revision of manuscript: Nils Habbe, Juliane Liese, Wolf Otto Bechstein, Teresa Schreckenbach and Juliane Liese
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Compliance with ethical standards This study was not funded. Conflicts of interest The authors declare that they have no conflicts of interest. Ethical approval All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. The study was approved by the local ethical committee of Frankfurt University (IRB No. 236/14).
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