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DOI: 10.1055/s-0041-1735594
Evolution of a Glaucoma Fellow's Surgical Training: Improvements in Tube Shunt Case Times during the Academic Year
Abstract
Purpose The aim of the study is to report changes in tube shunt placement surgical case times for glaucoma fellows during the course of the academic year.
Patients and Methods Electronic health records were retrospectively reviewed to determine patient demographics, surgical case times (defined as procedure start time to procedure end time), and glaucoma fellow involvement. Only cases with a glaucoma fellow as the primary surgeon were included. Operative case times were compared by first and second halves of the academic year (beginning in July and ending in June) using a two-tailed t-test.
Results Five hundred and seventy-three individual tube shunt surgeries (385 Ahmed, 188 Baerveldt) performed by 28 glaucoma fellows (17 females, 11 males) at Duke University Eye Center and University of North Carolina Medical Center were included. Overall, case times were significantly shorter in the second half of the academic year as compared with the first (55.3 ± 17.1 minutes vs. 61.0 ± 17.4 minutes, p <0.001). Both male (57.3 ± 16.8 minutes vs. 63.2 ± 18.6 minutes, p = 0.008) and female (53.5 ± 17.3 minutes vs. 59.3 ± 16.4 minutes, p = 0.003) fellows demonstrated shorter case times over the academic year; additionally, female fellows trended toward shorter case times than male fellows in both the first half (p = 0.072) and second half (p = 0.053) of the academic year. Fellows also exhibited shorter case times with both Ahmed implants (54.1 ± 16.2 minutes vs. 59.3 ± 15.8 minutes, p = 0.002) and Baerveldt implants (57.8 ± 18.9 minutes vs. 64.2 ± 20.0 minutes, p = 0.025) cases over the academic year. Baerveldt case times were significantly longer than Ahmed cases in the first half (p = 0.028) and trended toward being longer than Ahmed cases in the second half (p = 0.070).
Conclusion Across 5 years at two academic institutions, glaucoma fellows had shorter primary tube shunt surgical case times in the second half of the academic year. These findings reflect improvement in surgical efficiency throughout glaucoma fellowship. These findings should be taken into consideration when scheduling trainee surgeries at academic medical centers at different points in the academic year.
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Surgical education in ophthalmology is imperative for ensuring patient safety and preparing future physicians for independent surgical practice. In the subspecialty of glaucoma, fellows commit 1 year following ophthalmology residency to gain additional surgical experience in complex aqueous filtering surgeries, including tube shunt placement and trabeculectomy. While the importance of surgical education in glaucoma fellowship is widely acknowledged, there is limited literature reporting the quantitative impact of a dedicated fellowship program on surgical efficiency. Additionally, the logistical implications of surgical scheduling in ophthalmology fellowship programs at various points in the academic year have not been explored in detail.
Several studies have sought to characterize trainee surgical outcomes in ophthalmic surgical training programs.[1] [2] [3] [4] [5] [6] [7] For residents, surgical experience is one of the primary drivers of improvements in operative case times for cataract surgery over the course of training, with more cases yielding shorter case times, particularly early in training.[8] [9] [10] While trainees may need a considerable number of cases as primary surgeon to gain surgical mastery, there is a clear opportunity cost of trainee surgical involvement. A recent cost-analysis paper found that in California (fiscal year 2014), 1 minute of operating room time was worth $36 to $37.[11] In strabismus surgery, the cost of resident involvement was reported to be $3141.95 per year due to increased operative times.[12] For orthopaedic surgery residents in 1996 to 1997, operating room costs were increased by $661.85 on average for trainee cases due to increased operative time.[13] In plastic surgery, 2011 costs were estimated to be $275 per trainee involved in a given case, and over $440 per case for craniofacial surgical fellows.[14] As such, understanding potential improvements in surgical case times over the course of glaucoma fellowship could help us better measure surgical training and could galvanize efforts to improve surgical education for fellows.
The landscape of glaucoma filtering surgery has changed dramatically in the last two decades. Studies have shown an increase in tube shunt placement with a concomitant decrease in trabeculectomy surgery among national Medicare claims[15] as well as resident and fellow case logs[16] [17]; this may be due to several factors, including the feared complications of bleb filtering surgery (bleb-related endophthalmitis, hypotonous maculopathy) as well as improvements in tube shunt devices. In the wake of the Tube versus Trabeculectomy study[18] and the Primary Tube Versus Trabeculectomy study,[19] which have provided invaluable comparisons between tube shunt and trabeculectomy surgeries, it is likely that rates of tube shunt administration will continue to increase. Education in tube shunt placement will be a core component of glaucoma surgical training for the foreseeable future; however, the current state of glaucoma fellows' case times for tube shunt placement has not been reported. As such, we sought to report operative case times for glaucoma fellows at the Duke University Eye Center and the University of North Carolina (UNC) over a 5-year period (2014–2019), to determine whether fellows attain greater surgical efficiency over the course of the academic year.
Materials and Methods
Prior approval for this retrospective study was obtained from the Duke University Health System and University of North Carolina Institutional Review Boards, and the requirement for informed consent was waived. This study complied with the Health Insurance Portability and Accountability Act of 1996 and followed the tenets of the Declaration of Helsinki.
Retrospective clinical data regarding tube shunt placement cases was abstracted using the electronic health record at UNC and Duke (Epic, Verona, WI). We reviewed all procedures coded using Current Procedural Terminology 66180 for aqueous shunt placement performed from July 2014 to June 2019. All cases that were primarily performed by the fellow were identified and included by attending faculty attestation and/or documentation. The cases included constitute a representative sample of each fellow's surgical cases with select faculty at each institution and are not intended to represent the holistic surgical curriculum offered by each respective program. Tube shunt procedures performed in combination with a secondary procedure (i.e., cataract surgery, trabeculectomy, vitrectomy) were excluded from analysis to eliminate the confounding effect of a second procedure on operative time.
Patient demographic data (age and sex), procedure date, fellow involved, attending/supervising surgeon, and type of tube shunt placed (Ahmed glaucoma valve, New World Medical Inc, Rancho Cucamonga, CA; Baerveldt glaucoma implant, Abbott Laboratories Inc, Abbott Park, IL) were recorded. For the purposes of statistical analysis, procedure dates were characterized as occurring during the first or second half of the academic year (July–June); as such, first-half cases were performed between July 1 and December 31 of a given year, and second-half cases were performed between January 1 and June 31 of a given year.
Statistical analysis was performed using Stata, software version 16.1 (StataCorp, College Station, TX). Operative case times were compared between groups using an independent-sample, two-tailed t-test, with the level of significance defined as <0.05.
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Results
Five hundred and seventy-three tube shunt placement surgeries performed by 28 glaucoma fellows at Duke University Medical Center and UNC Health System over a 5-year period (2014–2019) were analyzed. Of the 28 fellows, 22 (79%) were trained at Duke and six trained at UNC (21%). Seventeen (61%) fellows were female, and 11 (39%) were male. Of the 573 surgeries performed, all operations involved the fellow as primary operator under supervision of an attending surgeon, and no surgeries included a combined procedure (i.e., cataract surgery, trabeculectomy, vitrectomy, etc.). Demographic data pertinent to the surgeries performed is detailed in [Table 1]. Of 573 tube shunt placements, 385 (67%) were Ahmed glaucoma valves and 188 (33%) were Baerveldt glaucoma drainage devices. The mean patient age was 66.3 (standard deviation 14.1) years. Two hundred seventy-nine (51%) patients were female, and 328 (57%) of the surgeries were performed at Duke.
Abbreviations: SD, standard deviation; UNC, University of North Carolina.
Surgical case times by half of the academic year (i.e., first half, July–December, second half January–June) are reported in [Table 2]. When pooling data from all fellows, second half cases were significantly shorter than first half cases, by an average of 6 minutes per case (55.3 ± 17.1 minutes vs. 61.0 ± 17.4 minutes, p <0.001). Female fellows trended toward shorter first and second half case times than male fellows; however, both female (53.5 ± 17.3 minutes vs. 59.3 ± 16.4 minutes, p = 0.003) and male (57.3 ± 16.8 minutes vs. 63.2 ± 18.6 minutes, p = 0.008) fellows had significantly shorter second half case times when compared with first half case times. Duke (55.5 ± 14.4 minutes vs. 59.2 ± 15.9 minutes, p = 0.026) and UNC (55.0 ± 20.2 minutes vs. 63.3 ± 19.2 minutes, p = 0.001) fellows both had significantly shorter case times in the second half of the academic year. Baerveldt case times were significantly longer than Ahmed case in the first half (64.2 ± 20.0 minutes vs. 59.3 ± 15.8 minutes, p = 0.028) but only trended toward being longer than Ahmed cases in the second half (57.8 ± 18.9 minutes vs. 54.1 ± 16.2 minutes, p = 0.070).
First half[a] case times in minutes, mean ± SD (N) |
Second half case times in minutes, mean ± SD (N) |
p-Value[b] |
|
---|---|---|---|
All fellows |
61.0 ± 17.4 (264) |
55.3 ± 17.1 (309) |
<0.001 |
Male fellows |
63.2 ± 18.6 (111) |
57.3 ± 16.8 (145) |
0.008 |
Female fellows |
59.3 ± 16.4 (153) |
53.5 ± 17.3 (164) |
0.003 |
UNC fellows |
63.3 ± 19.2 (112) |
55.0 ± 20.2 (133) |
0.001 |
Duke fellows |
59.2 ± 15.9 (152) |
55.5 ± 14.4 (176) |
0.026 |
Ahmed cases |
59.3 ± 15.8 (175) |
54.1 ± 16.2 (210) |
0.002 |
Baerveldt cases |
64.2 ± 20.0 (89) |
57.8 ± 18.9 (99) |
0.025 |
Abbreviations: SD, standard deviation; UNC, University of North Carolina.
a Date used were from the academic calendar year. First half dates fell between July and December in a given year; second half dates fell between January and June.
b p-Value from two-tailed t-test, p-value less than 0.05 was considered significant.
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Discussion
In this retrospective study of surgical case times among glaucoma fellows at two tertiary academic medical centers, we found that surgical case times were significantly shorter in the second half of the academic year for all fellows, suggesting an improvement in surgical efficiency with increasing surgical volume and supervised surgical education. We also report that surgical case times in the first half of fellowship (which may, in part, reflect baseline surgical experience prior to fellowship) did not significantly differ between male and female fellows, although female fellows tended to have shorter case times in the first and second halves of the academic year. Additionally, after 1 year of glaucoma fellowship, fellows at Duke and UNC had nearly identical average case times (UNC 55.0 ± 20.2 minutes, Duke 55.5 ± 14.4 minutes). While Baerveldt cases were longer than Ahmed cases in the first half of the academic year, this difference only trended toward significance in the second half, and significant improvements in both Ahmed and Baerveldt case times were observed when comparing first to second half cases. These findings, taken together, suggest that fellows become significantly more efficient surgeons during the academic year, which may have implications for surgical scheduling at academic medical centers and emphasizes the value of surgical experience in glaucoma training.
In an analysis of resident-performed and attending-performed tube shunt placements in a United States ophthalmology residency program, clinical outcomes were found to be similar; however, resident-performed cases were significantly longer than the attending cases (55 minutes vs. 50 minutes, p = 0.02).[7] While our study did not seek to explicitly compare fellow-performed cases with attending-performed cases, these results are consistent with our study, which showed longer case times at the beginning of fellowship (just following residency) when compared with the end of fellowship (at the point of transition to attending surgeon). Understanding fellow-performed surgical case times is important for assessing the true cost of glaucoma fellow education, as case times significantly influence the cost and efficiency of providing surgical care.[11] [12] While our study only characterizes surgical case times among fellows at two academic centers over 5 years, we are able to provide an estimate of expected, average case times for glaucoma fellows during the first and second half of academic training, which may be used by perioperative administration to forecast operating room availability and minimize unnecessary costs associated with under-prediction of operative case times, particularly in the beginning of the academic year. A prior study showed that first cataract surgery cases in a given day are longer than subsequent cases; further analyses may reveal unique trends in glaucoma surgery performed by fellows throughout the day, which could further inform planned case times.[20]
Our preliminary analysis suggests that fellow gender and training institution did not significantly impact operative case times at the end of the academic year. In this study of 28 fellows, a variety of ophthalmology residency programs were represented; however, we did not specifically assess variation in first half surgical case times with varying levels of glaucoma surgical experience during residency. This would likely be difficult to assess without residual confounding, as most training programs have exceedingly few primary glaucoma surgeries performed by residents, and resident wet laboratory/simulation experience may also influence surgical comfort/efficiency in early fellowship. It is possible that further study across multiple institutions may reveal disparities in surgical experience prior to glaucoma fellowship between various fellowship programs. The relationship between fellow gender and surgical case times may be noncontributory; however, it is notable that female surgeons trended toward shorter cases in both halves of the academic year.
This study is limited by several factors inherent to its retrospective nature. As we are collecting historical case times using the electronic health record retrospectively, we cannot independently confirm that recorded case times are reflective of actual intraoperative time. Additionally, while case times were generally consistent between Duke and UNC, we cannot rule out that minor differences in operating room workflow and recording of procedure start and end times between institutions could have influenced our results. We also only included cases in which we could definitively state that the fellow was the primary operator in all cases. Thus, each fellow performed significantly more cases in a given academic year that were not included in this study. As such, our study is not reflective of the holistic surgical experiences at either fellowship program and should not be taken as an objective assessment of fellow surgical volume and/or experience at the program. Additionally, while we excluded combination surgeries due to case-to-case variability, we cannot fully control other factors contributing to case time variability, including prior ocular surgeries, intraoperative complications, or extenuating circumstances leading to outliers in operative case times. We have attempted to control for these potential confounders by including a large number of primary tube shunt placements (intentionally excluding tube shunt revision/replacement) which are likely very homogenous inpatient presentation and case difficulty. We analyzed Ahmed and Baerveldt tubes separately and compared with one another given the potential for differences due to procedural considerations. Overall, we feel that our cohort is representative of routine, uncomplicated primary tube shunt placements by glaucoma fellows at tertiary academic medical centers. The inclusion of other centers in future studies would improve the generalizability of our results. Finally, one cannot presume that shorter case times are equivalent to “better” surgical care, as one can perform a surgery quickly and carelessly. However, it is exceedingly unlikely that 28 fellows under close and direct supervision by attending faculty became more reckless over the course of the academic year. To definitively state this, visual outcomes would need to be included, which would require a carefully designed prospective study with strict exclusion criteria for alternative sources of complications including comorbid ocular conditions and unrelated surgery or trauma, for example.
This study provides a foundation for further research into glaucoma fellow education and surgical performance throughout the academic year. This study can also be applied to other surgical fields and could serve as a basis for more efficient operative room scheduling with regards to trainees. Future directions for research include assessing clinical outcomes (i.e., intraocular pressure control, visual acuity) in fellow-performed cases throughout the academic year, characterizing operative case times for other common surgical procedures (i.e., trabeculectomy, phacoemulsification), characterizing fellows' subjective perceptions of improvement throughout the academic year prospectively, and inclusion of fellow-performed cases at other tertiary academic medical centers. In this study, we show that surgical efficiency, as assessed using the surrogate of operative case times, improves over the course of the academic year among glaucoma fellows.
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Conflict of Interest
None declared.
Précis
This retrospective analysis of glaucoma fellows at two academic institutions over a 5-year period demonstrates that surgical tube shunt case times decrease over the academic year. These findings may be used to guide operative scheduling of trainee surgical cases at academic centers.
Financial Support
None.
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References
- 1 Belyea DA, Brown SE, Rajjoub LZ. Influence of surgery simulator training on ophthalmology resident phacoemulsification performance. J Cataract Refract Surg 2011; 37 (10) 1756-1761
- 2 Abe RY, Shigueoka LS, Vasconcellos JPC, Costa VP. Primary trabeculectomy outcomes by glaucoma fellows in a tertiary hospital in Brazil. J Glaucoma 2017; 26 (11) 1019-1024
- 3 Biggerstaff KS, Vincent RD, Lin AP, Orengo-Nania S, Frankfort BJ. Trabeculectomy outcomes by supervised trainees in a veterans affairs medical center. J Glaucoma 2016; 25 (08) 669-673
- 4 Kang JM, Padmanabhan SP, Schallhorn J, Parikh N, Ramanathan S. Improved utilization of operating room time for trainee cataract surgery in a public hospital setting. J Cataract Refract Surg 2018; 44 (02) 186-189
- 5 Karaconji T, Mercieca K, Romera P, McNaught A, Anand N. A comparison of deep sclerectomy trainer versus trainee outcomes. J Glaucoma 2019; 28 (05) 427-432
- 6 Walkden A, Huxtable J, Senior M. et al. Trabeculectomy training in England: are we safe at training? Two-year surgical outcomes. Eye (Lond) 2018; 32 (07) 1253-1258
- 7 Thangamathesvaran L, Crane E, Modi K, Khouri AS. Outcomes of resident-versus attending-performed tube shunt surgeries in a United States Residency Program. J Curr Glaucoma Pract 2018; 12 (02) 53-58
- 8 Liebman DL, McKay KM, Haviland MJ, Moustafa GA, Borkar DS, Kloek CE. Quantifying the educational benefit of additional cataract surgery cases in ophthalmology residency. J Cataract Refract Surg 2020; 46 (11) 1495-1500
- 9 Wiggins MN, Warner DB. Resident physician operative times during cataract surgery. Ophthalmic Surg Lasers Imaging 2010; 41 (05) 518-522
- 10 Taravella MJ, Davidson R, Erlanger M, Guiton G, Gregory D. Characterizing the learning curve in phacoemulsification. J Cataract Refract Surg 2011; 37 (06) 1069-1075
- 11 Childers CP, Maggard-Gibbons M. Understanding costs of care in the operating room. JAMA Surg 2018; 153 (04) e176233
- 12 Winter TW, Olson RJ, Larson SA, Oetting TA, Longmuir SQ. Resident and fellow participation in strabismus surgery: effect of level of training and number of assistants on operative time and cost. Ophthalmology 2014; 121 (03) 797-801
- 13 Farnworth LR, Lemay DE, Wooldridge T. et al. A comparison of operative times in arthroscopic ACL reconstruction between orthopaedic faculty and residents: the financial impact of orthopaedic surgical training in the operating room. Iowa Orthop J 2001; 21: 31-35
- 14 Sasor SE, Flores RL, Wooden WA, Tholpady S. The cost of intraoperative plastic surgery education. J Surg Educ 2013; 70 (05) 655-659
- 15 Ramulu PY, Corcoran KJ, Corcoran SL, Robin AL. Utilization of various glaucoma surgeries and procedures in Medicare beneficiaries from 1995 to 2004. Ophthalmology 2007; 114 (12) 2265-2270
- 16 Chadha N, Liu J, Teng CC. Resident and fellow glaucoma surgical experience following the tube versus trabeculectomy study. Ophthalmology 2015; 122 (09) 1953-1954
- 17 Chadha N, Warren JL, Liu J, Tsai JC, Teng CC. Seven- and eight-year trends in resident and fellow glaucoma surgical experience. Clin Ophthalmol 2019; 13: 303-309
- 18 Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL. Tube versus Trabeculectomy Study Group. Treatment outcomes in the tube versus trabeculectomy (TVT) study after five years of follow-up. Am J Ophthalmol 2012; 153 (05) 789-803.e2
- 19 Gedde SJ, Feuer WJ, Lim KS. et al; Primary Tube Versus Trabeculectomy Study Group. Treatment outcomes in the primary tube versus trabeculectomy study after 3 years of follow-up. Ophthalmology 2020; 127 (03) 333-345
- 20 Gupta D, Taravati P. Effect of surgical case order on cataract surgery complication rates and procedure time. J Cataract Refract Surg 2015; 41 (03) 594-597
Address for correspondence
Publication History
Received: 08 April 2020
Accepted: 05 August 2021
Article published online:
10 November 2021
© 2021. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/)
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References
- 1 Belyea DA, Brown SE, Rajjoub LZ. Influence of surgery simulator training on ophthalmology resident phacoemulsification performance. J Cataract Refract Surg 2011; 37 (10) 1756-1761
- 2 Abe RY, Shigueoka LS, Vasconcellos JPC, Costa VP. Primary trabeculectomy outcomes by glaucoma fellows in a tertiary hospital in Brazil. J Glaucoma 2017; 26 (11) 1019-1024
- 3 Biggerstaff KS, Vincent RD, Lin AP, Orengo-Nania S, Frankfort BJ. Trabeculectomy outcomes by supervised trainees in a veterans affairs medical center. J Glaucoma 2016; 25 (08) 669-673
- 4 Kang JM, Padmanabhan SP, Schallhorn J, Parikh N, Ramanathan S. Improved utilization of operating room time for trainee cataract surgery in a public hospital setting. J Cataract Refract Surg 2018; 44 (02) 186-189
- 5 Karaconji T, Mercieca K, Romera P, McNaught A, Anand N. A comparison of deep sclerectomy trainer versus trainee outcomes. J Glaucoma 2019; 28 (05) 427-432
- 6 Walkden A, Huxtable J, Senior M. et al. Trabeculectomy training in England: are we safe at training? Two-year surgical outcomes. Eye (Lond) 2018; 32 (07) 1253-1258
- 7 Thangamathesvaran L, Crane E, Modi K, Khouri AS. Outcomes of resident-versus attending-performed tube shunt surgeries in a United States Residency Program. J Curr Glaucoma Pract 2018; 12 (02) 53-58
- 8 Liebman DL, McKay KM, Haviland MJ, Moustafa GA, Borkar DS, Kloek CE. Quantifying the educational benefit of additional cataract surgery cases in ophthalmology residency. J Cataract Refract Surg 2020; 46 (11) 1495-1500
- 9 Wiggins MN, Warner DB. Resident physician operative times during cataract surgery. Ophthalmic Surg Lasers Imaging 2010; 41 (05) 518-522
- 10 Taravella MJ, Davidson R, Erlanger M, Guiton G, Gregory D. Characterizing the learning curve in phacoemulsification. J Cataract Refract Surg 2011; 37 (06) 1069-1075
- 11 Childers CP, Maggard-Gibbons M. Understanding costs of care in the operating room. JAMA Surg 2018; 153 (04) e176233
- 12 Winter TW, Olson RJ, Larson SA, Oetting TA, Longmuir SQ. Resident and fellow participation in strabismus surgery: effect of level of training and number of assistants on operative time and cost. Ophthalmology 2014; 121 (03) 797-801
- 13 Farnworth LR, Lemay DE, Wooldridge T. et al. A comparison of operative times in arthroscopic ACL reconstruction between orthopaedic faculty and residents: the financial impact of orthopaedic surgical training in the operating room. Iowa Orthop J 2001; 21: 31-35
- 14 Sasor SE, Flores RL, Wooden WA, Tholpady S. The cost of intraoperative plastic surgery education. J Surg Educ 2013; 70 (05) 655-659
- 15 Ramulu PY, Corcoran KJ, Corcoran SL, Robin AL. Utilization of various glaucoma surgeries and procedures in Medicare beneficiaries from 1995 to 2004. Ophthalmology 2007; 114 (12) 2265-2270
- 16 Chadha N, Liu J, Teng CC. Resident and fellow glaucoma surgical experience following the tube versus trabeculectomy study. Ophthalmology 2015; 122 (09) 1953-1954
- 17 Chadha N, Warren JL, Liu J, Tsai JC, Teng CC. Seven- and eight-year trends in resident and fellow glaucoma surgical experience. Clin Ophthalmol 2019; 13: 303-309
- 18 Gedde SJ, Schiffman JC, Feuer WJ, Herndon LW, Brandt JD, Budenz DL. Tube versus Trabeculectomy Study Group. Treatment outcomes in the tube versus trabeculectomy (TVT) study after five years of follow-up. Am J Ophthalmol 2012; 153 (05) 789-803.e2
- 19 Gedde SJ, Feuer WJ, Lim KS. et al; Primary Tube Versus Trabeculectomy Study Group. Treatment outcomes in the primary tube versus trabeculectomy study after 3 years of follow-up. Ophthalmology 2020; 127 (03) 333-345
- 20 Gupta D, Taravati P. Effect of surgical case order on cataract surgery complication rates and procedure time. J Cataract Refract Surg 2015; 41 (03) 594-597