![The World Congress on Controversies in Obstetrics, Gynecology and Infertility (COGI). Click here to learn more.]({"type":"image" , "src" : "/sda/112382/JournalAd-COGI2024-Leaderboard.jpg"})
Abstract
Background
To determine the association of trainees involvement with surgical outcomes of abdominal and laparoscopic myomectomy including operative time, rate of transfusion, and complications.
Methods
A retrospective cohort study of 1145 patients who underwent an abdominal or laparoscopic myomectomy from 2008–2012 using the American College of Surgeons National Surgical Quality Improvement Program database (Canadian Task Force Classification II-2).
Results
Overall, 64% of myomectomies involved trainees. Trainees involvement was associated with a longer operative time for abdominal myomectomies (mean difference 20.17 minutes, 95% Confidence Interval (CI) [11.37,28.97], p < 0.01) overall and when stratified by fibroid burden. For laparoscopic myomectomy, there was no difference in operative time between trainees vs no trainees involvement (mean difference 4.64 minutes, 95% CI [−18.07,27.35], p = 0.67). There was a higher rate of transfusion with trainees involvement for abdominal myomectomies (10% vs 2%, p < 0.01; Odds Ratio (OR) 5.62, 95% CI [2.53,12.51], p < 0.01). Trainees involvement was not found to be associated with rate of transfusion for laparoscopic myomectomy (4% vs 5%, p = 0.86; OR 0.82, 95% CI [0.16,4.14], p = 0.81). For abdominal myomectomy, there was a higher rate of overall complications (15% vs 5%, p < 0.01; OR 2.96, 95% CI [1.77,4.93], p < 0.01) and minor complications (14% vs 4%, p < 0.01; OR 3.71, 95% CI [2.09,6.57], p < 0.01) with no difference in major complications (3% vs 2%, p = 0.23). For laparoscopic myomectomy, there was no difference in overall (6% vs 10% p = 0.41; OR 0.59, 95% CI [0.18,2.01], p = 0.40), major (2% vs 0%, p = 0.38), or minor (5% vs 10%, p = 0.32; OR 0.52, 95% CI [0.15,1.79], p = 0.30) complications.
Conclusion
Trainees involvement was associated with increased operative time, rate of transfusion, and complications for abdominal myomectomy, however, did not impact surgical outcomes for laparoscopic myomectomy.
PLAIN LANGUAGE SUMMARY
Title: Trainees Involvement in Myomectomy
The goal of our study was to determine the association of trainees involvement with surgical outcomes of fibroid excision surgery or myomectomy. We conducted a study of abdominal and laparoscopic myomectomies using an international surgical database. We found that trainees involvement in myomectomy was associated with increased operative time, rate of transfusion, and complications for abdominal myomectomy. However, trainees involvement did not impact surgical outcomes for laparoscopic myomectomy.
Introduction
The Halsteadian theory of “see one, do one, teach one” has dominated the principles of surgical training. Although priorities of patient safety and cost-savings have influenced trainees surgical autonomy, involvement in the operating room remains the cornerstone of surgical training (Kotsis and Chung Citation2013, Schoenfeld et al. Citation2013). There have been several studies in the surgical literature evaluating the association of trainees involvement with surgical outcomes (Schoenfeld et al. Citation2013, Castleberry et al. Citation2013, Hernández-Irizarry et al. Citation2012, Papandria et al. Citation2012, Matulewicz et al. Citation2014, Igwe et al. Citation2014, Freeman et al. Citation2017, Barber et al. Citation2016, Rajakumar et al. Citation2018, Sheyn et al. Citation2019). Within gynaecologic surgery, studies have demonstrated prolonged operative time however mixed results regarding whether trainees involvement is associated with overall, major, or minor complications including risk of blood transfusion. Furthermore, there is limited research on major gynaecologic procedures other than hysterectomy and on the impact of a minimally invasive approach (Igwe et al. Citation2014, Freeman et al. Citation2017, Barber et al. Citation2016, Rajakumar et al. Citation2018, Sheyn et al. Citation2019).
Myomectomy is one of the most frequently performed gynaecologic procedures. It is a core competency of training in the field of Obstetrics and Gynaecology internationally and is increasingly performed in a minimally invasive fashion (Baird et al. Citation2003, American College of Obstetricians and Gynecologists Citation2013, Grand View Research 2020). However, myomectomies are complex surgical procedures, with the risk of blood transfusion as high as 10% (Kim et al. Citation2020). It is therefore prudent that we understand the impact of trainees involvement on outcomes of myomectomy to balance education with patient safety. To our knowledge, whether trainees involvement is associated with surgical outcomes of myomectomy is unknown. Furthermore, no studies have evaluated the impact of an abdominal versus (vs) laparoscopic approach to myomectomy (Schoenfeld et al. Citation2013, Castleberry et al. Citation2013, Hernández-Irizarry et al. Citation2012, Papandria et al. Citation2012, Matulewicz et al. Citation2014, Igwe et al. Citation2014, Freeman et al. Citation2017, Barber et al. Citation2016, Rajakumar et al. Citation2018, Sheyn et al. Citation2019).
We evaluated whether trainees involvement is associated with surgical outcomes including operative time and rate of transfusion for abdominal and laparoscopic myomectomy. We hypothesised that trainees involvement would be associated with operative time and rate of transfusion for abdominal and laparoscopic myomectomy.
Methods
We conducted a retrospective cohort study using the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP Participant Use Data File (PUF) Citation2008) database. Trainees involvement was included as a NSQIP variable until 2012. Therefore, patients who underwent an abdominal or laparoscopic myomectomy from 1 January 2008 – 31 December 2012 were included in this study. The ACS NSQIP is a prospective, peer-controlled, nationally validated database that quantifies 30-day, risk-adjusted surgical outcomes with the goal of improving the quality of surgical care. Currently, >500 hospitals voluntarily participate in ACS NSQIP internationally. Trained clinical nurse reviewers prospectively collect variables including patient demographics, operative variables, and 30-day postoperative outcomes (ACS 2022). The NSQIP data is periodically audited and has a high inter-rater reliability with an overall disagreement rate of 1.56% (Shiloach et al. Citation2010).
Current Procedural Terminology (CPT) codes were used to identify patients who underwent an abdominal (58140, 58146) or laparoscopic (58545, 58546) myomectomy. CPT codes were further used to classify patients by number and/or weight of fibroids excised for abdominal myomectomy (58140, 1-4 myoma(s) and/or weight ≤250 g and 58146, ≥5 myomas and/or weight >250 g) and laparoscopic myomectomy (58545, 1–4 myomas and/or weight ≤250 g and 58546, ≥5 myomas and/or weight >250 g). Myomectomies with concurrent procedures were excluded. Patient records that did not include information regarding trainees involvement were excluded.
The primary outcomes were operative time and rate of transfusion. Secondary outcomes included the rate of 30-day postoperative overall, major, and minor complications. Major postoperative complications included deep venous thrombosis, pulmonary embolism, stroke/cerebrovascular accident, myocardial infarction, cardiopulmonary arrest, pneumonia, renal failure, sepsis/shock, deep surgical site infection, organ space infection, wound disruption, nerve injury, re-intubation, unplanned re-operation/return to the operating room, and death within 30 days. Minor complications included blood transfusion, urinary tract infection, and superficial wound/surgical site infection.
The primary exposure of interest was trainees involvement, defined as trainees intraoperative participation as coded in the NSQIP database (ACS_NSQIP_ACS NSQIP Participant Use Data File (PUF) Citation2008– 2012). Obstetrics and Gynaecology training is 4–7 years in length internationally ranging from 4 years in the United States to 7 years in the United Kingdom (The Savvy IMG). In our study, we utilised the United States definition of residency and fellowship training as most participating NSQIP instructions are in the United States. Resident involvement was coded as post-graduate year 1-4, and fellow involvement as post graduate year 5 or greater. The surgical approach (abdominal vs laparoscopic) was defined by CPT code. Patient demographics and preoperative factors were also extracted from the database. Demographic factors included patient age and race. Patient preoperative factors included body mass index (BMI), hypertension requiring medication, diabetes requiring oral therapy or insulin, smoking in the last year, and the American Society of Anaesthesiologists (ASA) class.
Patient demographics, preoperative factors, intraoperative characteristics, and 30-day postoperative complications were summarised by median with the 25th and 75th percentiles (interquartile range, IQR, for continuous variables), and frequency with percentages (for categorical variables). The differences between procedures with and without trainees involvement were assessed with Wilcoxon rank tests or Pearson’s χ2 tests. To evaluate the associations between trainees involvement (for both trainees vs no trainese groups and resident vs fellow vs no trainees groups) and surgical outcomes, multivariable linear regressions (for outcome of operative time) and logistic regressions (for outcomes of transfusion and complications) were used. In all models, we included the interaction terms between trainees involvement and surgical approach to allow the trainees involvement–outcome association to be different by surgical approaches (abdominal vs laparoscopic). Potential confounders including patient age, diabetes, hypertension, and ASA class were adjusted in the models. Mean differences or Odds Ratios (aOR) with 95% Confidence Intervals (CI) and p-values estimated from the models were reported for each outcome as appropriate. All analyses were conducted using R statistical software (version 4.1, R Foundation for Statistical Computing, Vienna, Austria) (R Core Team Citation2021).
This study was reviewed by the Vanderbilt University Medical Centre Institutional Review Board and deemed exempt as it is non-human subject research (IRB: #212223, 12/14/2021). Registration is not applicable.
Results
There were 3138 abdominal or laparoscopic myomectomies (CPT codes 58545, 58546, 58140, 58146) identified in the NSQIP database between 2008 – 2012. Among these, 1145 procedures that were not associated with concurrent CPT codes and had information regarding trainees involvement were included as participants for the study. Overall, 64% of patients had trainees involvement in their myomectomy. For abdominal myomectomy, 60% of patients had trainees involvement and for laparoscopic myomectomy, 80% had trainees involvement ().
Table 1. Categories of myomectomies and associated trainees involvement.
For patient demographics and characteristics including comorbidities, there were no differences in age, BMI, presence of diabetes or hypertension requiring medication, current smoking within one year, and the American Society of Anaesthesiologists classification between the no trainees, resident, and fellow groups. However, there were racial differences between the groups. Patients with trainees involvement were more likely to be Black (resident 40%, fellow 26%, no trainees 24%, p < 0.01) and less likely to be white (resident 31%, fellow 24%, no trainees 54%, ). This demonstrates that Black patients are less likely than white patients to be cared for at private healthcare centres and more likely to be cared for at academic centres with trainees involvement in their care. This is an important factor to consider as we seek to address racial inequities in healthcare.
Table 2. Patient characteristics.
For the primary outcome of operative time, trainees involvement was associated with a longer total operative time for abdominal myomectomies (115 vs 89 minutes, p<.01) overall and stratified by fibroid burden: excision of 1–4 myomas/weight ≤250 g (103 vs 78 minutes, p<.01) and excision of ≥5 myomas/weight >250 g (141 vs 106 minutes, p<.01). For laparoscopic myomectomy, there was no difference in operative time between trainees vs no trainees involvement (155 vs 146 minutes, p = .88). When laparoscopic myomectomy was stratified between removal of 1–4 myoma/weight ≤250 g and removal of ≥5 myomas/weight >250 g, there remained no difference in operative time between the two groups (). For the primary outcome of transfusion, there was a higher rate of transfusion with abdominal myomectomy overall (10% vs 2%, p < .01) and when stratified by 1–4 myomas/weight ≤250 g (6% vs 2%, p = .02) and ≥5 myomas/weight >250 g (17% vs 2%, p < .01). There was no difference in the rate of transfusion for laparoscopic myomectomy (4% vs 5%, p=.86, ). For abdominal myomectomies, there was a higher rate of overall complications (15% vs 5%, p<.01) and minor complications (14% vs 4%, p<.01) with no difference in major complications (3% vs 2%, p = .23). For laparoscopic myomectomy there was no difference in overall (6% vs 10%, p = .41), major (2% vs 0%, p=.38), or minor (5% vs 10%, p = .32) complications ().
Table 3. Median operative time among procedures with and without trainees involvement, stratified by type of myomectomy.
Table 4. Rate of transfusion among procedures with and without trainees involvement, stratified by type of myomectomy.
Table 5. 30-day postoperative complications by trainees involvement.
These associations were further confirmed in the multivariable adjusted analyses. Compared with procedures without trainees involvement, those with trainees involvement were more likely to have longer operative time for abdominal myomectomy (mean difference 20.17 minutes, 95% Confidence Interval (CI) [11.37,28.9], p < 0.01), but not for laparoscopic myomectomy (4.64, [−18.07,27.35, p = 0.67). Compared with procedures without trainees involvement, those with trainees involvement were more likely to have a transfusion for abdominal myomectomy (OR 5.62, 95% CI [2.53,12.5], p < 0.01), but not for laparoscopic myomectomy (0.82, [0.16–1.14], p = 0.81). Procedures with trainees involvement were more likely to have any complication (OR 2.96, 95% CI [1.77,4.94], p < 0.01) or minor complication (3.71, [2.09,6.57], p < 0.01) for abdominal myomectomy, but not for laparoscopic myomectomy (any complication 0.59, [0.18 to 2.01], p = 0.40; minor complication 0.52, [0.15 to 1.79], p = 0.30, ).
Table 6. Adjusted associations between trainees involvement and surgical outcomes stratified by surgical approach.
We further delved into the association of trainees level (resident vs fellow) on outcomes of abdominal and laparoscopic myomectomy by comparing these outcomes with resident, fellow, and no trainees groups through multivariable adjusted analyses. For abdominal myomectomy, both resident (mean difference 19.20 minutes, 95% CI [10.14,28.26], p < 0.001) and fellow (26.48, [9.84,43.13], p = 0.002) involvement was associated with longer operative time when compared with no trainees involvement. However, there was no difference in fellow vs resident involvement on operative time (mean difference 7.28 minutes, 95% CI [−9.01,23.58], p = 0.38. For laparoscopic myomectomy, there was no difference in operative time between groups. Compared to procedures without trainees involvement, those with both resident (OR 4.62, 95% CI [2.04,10.46], p < 0.001) and fellow (13.54, [5.27,34.81], p < 0.001) involvement were more likely to have a transfusion for abdominal myomectomy, and cases with fellows were more likely to require transfusion than those with residents (2.93, [1.52,5.66], p = 0.001]. For laparoscopic myomectomy, there was no difference in rate of transfusion between groups. For abdominal myomectomy, there was a higher rate of any complication in resident (OR 2.56, 95% CI [1.51,4.33], p < 0.001) and fellow (6.07, [3.03,12.14], p < 0.001) groups, and procedures with fellows were more likely to have complications than those with residents (2.37, [1.32,4.28], p = 0.004). There was also a higher rate of minor complications with abdominal myomectomy for all groups. There were no differences in groups for any or minor complication for laparoscopic myomectomy (Table 1S).
Discussion
Our study demonstrated an increase in operative time with trainees involvement for abdominal myomectomy. This finding is consistent with previous research in gynaecologic surgery and other surgical specialties (Schoenfeld et al. Citation2013, Castleberry et al. Citation2013, Hernández-Irizarry et al. Citation2012, Papandria et al. Citation2012, Matulewicz et al. Citation2014, Igwe et al. Citation2014, Freeman et al. Citation2017, Barber et al. Citation2016, Rajakumar et al. Citation2018, Sheyn et al. Citation2019). This increase in operative time may be reflective of the nature of the academic training environment, which often also includes the involvement of not only surgical trainees, but also anaesthesia residents, medical and nursing students, and surgical technician trainees.
Interestingly, trainee involvement in laparoscopic myomectomy was not associated with an increase in operative time. There are several factors that may account for this finding. Laparoscopic myomectomies require an advanced level of technical skill (Alessandri et al. Citation2006). They may therefore be performed by more senior trainees, or the attending physician may be performing more of the procedure as the primary surgeon. Another potential explanation is the involvement of robotic assistance. Approximately 21–50% of myomectomies are performed robotically, and it has been demonstrated that robotic skills are more rapidly acquired than laparoscopic skills (Gobern et al. Citation2013, Bedient et al. Citation2009, Holloway et al. Citation2009). It is likely that a portion of the myomectomies in the laparoscopic group were performed with robotic assistance and contributed to the lack of difference in operative time for this group.
Our other primary outcome demonstrated an increased rate of transfusion in the trainees group for abdominal myomectomy, consistent with previous literature (Igwe et al. Citation2014, Barber et al. Citation2016, Rajakumar et al. Citation2018). Furthermore, our findings demonstrate that operative time may be a mediator in the relationship between trainees involvement and complication, specifically risk of transfusion, consistent with other studies (Barber et al. Citation2016, Catanzarite et al. Citation2015, Khuri et al. Citation2001. Accordingly, abdominal myomectomy with a high fibroid burden was associated with the greatest increase in operative time and the highest rate of transfusion. For laparoscopic myomectomy, there was no difference in operative time, which could partially explain why there was no increased risk of blood transfusion. Additionally, a decreased risk of blood transfusion for laparoscopic as compared to abdominal myomectomy was demonstrated in a recent study (Kim et al. Citation2020). While there are likely several contributing factors, part of the benefit may be in the insufflation pressure helping to decrease venous bleeding.
Similar to our study which demonstrated an increased risk of complications with trainees involvement in abdominal but not laparoscopic myomectomy, the data on impact of trainees involvement on complications is mixed. One study on vaginal hysterectomy demonstrated an increased risk of major complications while another demonstrated increased rates of overall complications with trainees presence (Barber et al. Citation2016, Rajakumar et al. Citation2018). Other studies on laparoscopic hysterectomy and pelvic reconstructive surgery have shown no increased risk of overall complications with trainees involvement (Igwe et al. Citation2014, Sheyn et al. Citation2019). The association between trainees involvement and complication rates thus likely varies based on the procedure itself, the skills required to effectively perform the procedure, and variation in training paradigms for the procedure.
When evaluating resident vs fellow involvement in abdominal myomectomy, there was no difference in operative time between groups however there was a higher rate of blood transfusion and complications in procedures involving fellows. This association may be because fellows are more likely to be involved in procedures that are more complex as they are more senior and skilled trainees. The lack of a difference in surgical outcomes between resident, fellow, and no trainees involvement in laparoscopic myomectomy may be due to several factors, including the low rate of transfusion and complications with laparoscopic myomectomies as compared to abdominal myomectomies in our study.
The benefits of performing minimally invasive surgery are well known (Aarts et al. Citation2015). In demonstrating that trainees presence does not impact surgical outcomes of laparoscopic myomectomy, regardless of trainees level, this study promotes the need for surgical training in minimally invasive techniques for complex gynaecologic procedures such as myomectomy.
Strengths of this study include the use of prospectively collected data from a reliable database that represents a diverse sample of patients and institutions in the United States. This allows for a large sample size to detect small, but significant differences in surgical outcomes, and allows for generalisability of the findings. We were also able to stratify abdominal and laparoscopic myomectomy by number and/or weight of fibroids, which is an effective means of standardising procedures. The main strength of this study is that it is the first to examine trainees impact on surgical outcomes of myomectomy, a commonly performed complex gynaecologic procedure.
A limitation of this study is the use of data until 2012. The variable coding for trainees involvement was no longer included in NSQIP after 2012. However, this database was still the most effective means to study our research question. There is also an inherent limitation with the use of CPT codes which categorise fibroids into limited categories and may not capture the true difference in complexity of myomectomies. Furthermore, trainees are more likely to be involved in procedures at academic teaching hospitals, where more medically and/or surgically complex patients may be referred. This may independently predispose patients to a longer operative time and/or higher risk of transfusion. Additionally, we did not evaluate preoperative haemoglobin levels, which are a factor in the risk of transfusion. However, there are many factors associated with risk of transfusion during myomectomy and we accounted for multiple contributing factors. Lastly, while we were able to specify trainees level, we were unable to determine the degree of trainees involvement in the myomectomies as this is not specified in NSQIP.
Trainees involvement was associated with increased operative time, rate of transfusion, and complications for abdominal myomectomy. Trainees involvement did not impact surgical outcomes for laparoscopic myomectomy.
Supplemental Material
Download MS Word (27 KB)Acknowledgements
We would like to thank the patients and institutions that participate in the collection of data for ACS NSQIP and allow the use of this data for research.
Disclosure statement
Oral presentation at AAGL 2022: 51st Global Congress on MIGS; 1–4 December 2022; Aurora, CO. The authors report no other conflict of interest. The American College of Surgeons National Surgical Quality Improvement Program and the hospitals participating in the ACS NSQIP are the source of the data used herein; they have not verified and are not responsible for the statistical validity of the data analysis or the conclusions derived by the authors.
Data availability statement
The authors confirm that the data supporting the findings of this study are available within the article and/or its supplementary materials.
Additional information
Funding
References
- Aarts, J.W., et al., 2015. Surgical approach to hysterectomy for benign gynaecological disease. The Cochrane Database of Systematic Reviews, 2015 (8), 1.
- ACS NSQIP Participant Use Data File (PUF) 2008 – 2012.
- Alessandri, F., et al., 2006. Randomized study of laparoscopic versus minilaparotomic myomectomy for uterine myomas. Journal of Minimally Invasive Gynecology, 13 (2), 92–7.
- American College of Obstetricians and Gynecologists 2013. Educational objectives: core curriculum in obstetrics and gynecology. Available from: https://www.acog.org/About-ACOG/ACOG-Departments/CREOG/CREOG-Search/CREOG-11th-Edition-of-Educational-Objectives [last accessed May 5, 2022].
- American College of Surgeons, 2022. Frequently asked questions 2022. Available from: https://www.facs.org/quality-programs/acs-nsqip/faq#:∼:text=Currently%2C%20about%20700%20hospitals%20use,the%20quality%20of%20their%20care [Last accessed May 5.].
- Baird, D.D., et al., 2003. High cumulative incidence of uterine leiomyoma in black and white women: ultrasound evidence. American Journal of Obstetrics and Gynecology, 188 (1), 100–107.
- Barber, E.L., Harris, B. and Gehrig, P.A., 2016. Trainee participation and perioperative complications in benign hysterectomy: the effect of route of surgery. American Journal of Obstetrics and Gynecology, 215 (2), 215.e1–215.e7.
- Bedient, C.E., et al., 2009. Comparison of robotic and laparoscopic myomectomy. American Journal of Obstetrics and Gynecology, 201 (6), 566.e1-5–566.e5.
- Castleberry, A.W., et al., 2013. Resident education in the era of patient safety: a nationwide analysis of outcomes and complications in resident-assisted oncologic surgery. Annals of Surgical Oncology, 20 (12), 3715–3724.
- Catanzarite, T., et al., 2015. Longer operative time during benign laparoscopic and robotic hysterectomy is associated with increased 30-day perioperative complications. Journal of Minimally Invasive Gynecology, 22 (6), 1049–1058.
- Freeman, A.H., et al., 2017. Does surgical teaching take time? Resident participation in minimally invasive hysterectomy for endometrial cancer. Journal of Minimally Invasive Gynecology, 24 (5), 783–789.
- Gobern, J.M., et al., 2013. Comparison of robotic, laparoscopic, and abdominal myomectomy in a community hospital. Journal of the Society of Laparoendoscopic Surgeons, 17 (1), 116–120.
- Grand View Research. Myomectomy Market Size, Share & Trends Analysis Report By Type (Abdominal, Hysteroscopic, Laparoscopic), By Product (Laparoscopic Power Morcellators, Harmonic Scalpel, Laparoscopic Sealer), By Region, and Segment Forecasts 2020. September Available from: https://www.grandviewresearch.com/industry-analysis/myomectomy-market. Accessed 5, May 2022].
- Hernández-Irizarry, R., et al., 2012. Impact of resident participation on laparoscopic inguinal hernia repairs: are residents slowing us down? Journal of Surgical Education, 69 (6), 746–752.
- Holloway, R.W., Patel, S.D. and Ahmad, S., 2009. Robotic surgery in gynecology. Scandinavian Journal of Surgery: Official Organ for the Finnish Surgical Society and the Scandinavian Surgical Society, 98 (2), 96–109.
- Igwe, E., et al., 2014. Resident participation in laparoscopic hysterectomy: impact of trainee involvement on operative times and surgical outcomes. American Journal of Obstetrics and Gynecology, 211 (5), 484.e1–484–e7.
- Khuri, S.F., et al., 2001. Comparison of surgical outcomes between teaching and nonteaching hospitals in the Department of Veterans Affairs. Annals of Surgery, 234 (3), 370–383. discussion 82-3.
- Kim, T., et al., 2020. Myomectomy associated blood transfusion risk and morbidity after surgery. Fertility and Sterility, 114 (1), 175–184.
- Kotsis, S.V. and Chung, K.C., 2013. Application of the "see one, do one, teach one" concept in surgical training. Plastic and Reconstructive Surgery, 131 (5), 1194–1201.
- Matulewicz, R.S., et al., 2014. Impact of resident involvement on urological surgery outcomes: an analysis of 40,000 patients from the ACS NSQIP database. The Journal of Urology, 192 (3), 885–890.
- Papandria, D., et al., 2012. Assessing trainee impact on operative time for common general surgical procedures in ACS-NSQIP. Journal of Surgical Education, 69 (2), 149–155.
- R Core Team 2021. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. Available from: https://www.R-project.org/ [Accessed 5 May 2022].
- Rajakumar, C., et al., 2018. Effect of surgical trainee presence on vaginal hysterectomy outcomes. Journal of Minimally Invasive Gynecology, 25 (6), 1088–1093.
- Schoenfeld, A.J., et al., 2013. The impact of resident involvement on post-operative morbidity and mortality following orthopaedic procedures: a study of 43,343 cases. Archives of Orthopaedic and Trauma Surgery, 133 (11), 1483–1491.
- Sheyn, D., et al., 2019. Impact of trainee involvement on complication rates following pelvic reconstructive surgery. Female Pelvic Medicine & Reconstructive Surgery, 25 (5), 351–357.
- Shiloach, M., et al., 2010. Toward robust information: data quality and inter-rater reliability in the American College of Surgeons National Surgical Quality Improvement Program. Journal of the American College of Surgeons, 210 (1), 6–16.
- The Savvy IMG 2018., 2024. Become an Obstetrics and Gynaecology Specialist in the UK: A comprehensive guide for IMGs. Available from: https://thesavvyimg.co.uk/obstetrics-gynaecology-guide-uk/ [Accessed 19 February 2024].