Abstract
AIM
To compare the incidence of intraoperative complications during primary phacoemulsification (phaco) surgery between resident surgeons (residents) and staff surgeons (specialists) and to objectively determine the difficulty of stages in phaco surgery.
METHODS
This retrospective study included cases of phaco cataract surgery performed between January and December 2019. There were no exclusion criteria. For each patient, demographics, clinical history, case complexity, type of surgeon, and operative details were reviewed. Primary outcomes included intraoperative complication rates and the objective measure of difficulty in the steps of the surgery performed by residents and specialists.
RESULTS
A total of 3272 cases were included; 7.4% (n=241) of cases were performed by residents. The overall complication rate was 5.4% (n=177). The intraoperative complication rate was significantly higher (P<0.001) in residents (n=33, 13.7%) than in specialists (n=144, 4.8%). The most frequent complications were posterior capsule tear (n=85, 2.6%), anterior capsule tear (n=50, 1.53%), zonular fiber loss (n=45, 1.38%), and dropped nucleus (n=15, 0.46%). Objectively, the most difficult steps during surgery were phaco in 66 (60.0%), capsulorhexis in 21 (19.1%), irrigation/aspiration in 13 (11.8%), hydrodissection in 9 (8.2%), and intraocular lens (IOL) implantation in 1 (0.9%) case.
CONCLUSION
Intraoperative complication rates are higher in residents than in specialists. The order of objective difficulty in phaco surgery steps is in line with the subjective findings of other surveys, revealing that the most challenging parts of phaco surgery are phaco and capsulorhexis.
Keywords: cataract, intraoperative complications, resident, phacoemulsification, staff surgeon
INTRODUCTION
Cataract surgery is one of the most commonly performed ophthalmic surgeries worldwide. Thus, learning to perform cataract surgery with phacoemulsification (phaco surgery) is an essential part of ophthalmology training programs[1]. Because of the increasing availability of surgical devices and technical advancement, complication rates are decreasing. However, intraoperative complication rates may differ between staff surgeons (specialists) and resident trainees (residents)[2]–[3]. Only a few large-scale studies have compared intraoperative complication rates between specialists and residents[4]–[6], and differences between these studies may be due to different structures in residency trainings. Thus, it is important to gain insight from different countries with different education systems to develop more effective training methods.
Although residency programs should provide trainees with the opportunity to improve their surgical skills, patient safety is always the most important aspect of the procedure. This duality poses a great dilemma in residency training programs. Phaco surgery is a single-surgeon operation, during which the specialist can supervise, leading the resident through the surgery verbally, and in case of intraoperative difficulty or complication, possibly take over and finish the surgery to ensure patient safety[5],[7]–[8]. Phaco surgery is a highly complex procedure with well-differentiated unique steps. Several studies have attempted to determine the difficult stages of phaco surgery for residents, albeit subjectively[9]–[10]. However, to our knowledge, no study has objectively analyzed this issue.
The primary aim of this study was to determine the incidence and types of intraoperative complications in phaco surgery in a tertiary eyecare center in Hungary and to compare these complications between residents and specialists. The secondary aim was to objectively assess the order of difficulty of phaco surgery steps for residents.
SUBJECTS AND METHODS
Ethical Approval
The study was conducted at a tertiary eyecare center in Hungary. The study was approved by the Regional and Institutional Committee of Science and Research Ethics of Semmelweis University, Hungary (No.121/2021). The study was performed in accordance with the Declaration of Helsinki Guidelines for Human Research. Written informed consent was obtained from the patients.
This retrospective review included 3272 consecutive patients who underwent primary phaco surgery performed by residents and specialists over a period of 1y, from January 1, 2019, to December 31, 2019, at the Department of Ophthalmology, Semmelweis University, Budapest, Hungary. For each subject, the clinical data were reviewed, which included patient demographics (sex, age, and eye laterality), clinical history (earlier intraocular surgeries), preoperative and postoperative ophthalmological status (case complexity), and operative details (usage of trypan blue dye staining, iris hooks, and intraoperative complications).
The factors contributing to the replacement of residents by specialists during phaco surgery were noted to objectively analyze which surgical steps were the most challenging for residents. Thirty-one specialists and 9 residents performed the phaco surgeries. One resident was in the second, 3 in the third, 3 in the fourth, and 2 in the fifth year of the residency. All surgeries included clear corneal incisions, continuous curvilinear capsulorhexis, and hydrodissection. Phaco techniques were performed in descending order as follows: phaco-crack (n=1338, 40.9%), stop-and-chop (n=780, 23.8%), phaco-chop (n=659, 20.1%), divide-and-conquer (n=436, 13.3%), and unclassifiable (n=59, 1.8%).
Statistical analysis was performed with statistica 8.0 (StatSoft Inc., Tulsa, OK, US). Data are expressed as the mean±standard deviation (SD). The Chi-square test was used to analyze the differences in the proportions of categorical variables. P<0.05 was considered statistically significant.
RESULTS
The study included 3272 consecutive cases. There were 1261 (38.5%) men and 2011 (61.5%) women in the study population. The mean patient age was 69.8±11.1y (range, 17mo-98y). Of these patients, 1659 (50.7%) underwent surgery on the right eye and 1613 (49.3%) underwent surgery on the left eye. There were 3158 (96.5%) corticonuclear, 80 (2.5%) mature, 22 posterior polar (0.7%), 8 (0.2%) traumatic, and 4 hypermature (0.1%) cataract cases.
Of the surgeries, 3031 (92.6%) were completed by specialists alone and 241 (7.4%) were performed by residents or by residents and specialists.
There were 2675 (81.8%) simple and 597 (18.2%) complex cataract surgeries. The most common complexities (Table 1) were patients with earlier vitrectomy (n=156, 4.8%), high axial myopia (n=114, 3.5%), corneal scar, corneal dystrophy or keratoconus (n=107, 3.3%), narrow angles (n=74, 2.3%), pseudoexfoliation or zonular fiber compromise (n=53, 1.6%), and small pupil or intraoperative floppy-iris syndrome (n=50, 1.5%).
Table 1. Complexities during cataract surgeries.
| Complexity | n (%) |
| Earlier vitrectomy | 156 (4.8) |
| High axial myopia | 114 (3.5) |
| Corneal scar, dystrophy, or keratoconus | 107 (3.3) |
| Narrow angles | 74 (2.3) |
| Pseudoexfoliation or zonular fiber compromise | 53 (1.6) |
| Small-pupil intraoperative floppy-iris syndrome | 50 (1.5) |
| Special cataract (posterior polar, traumatic, or hypermature) | 30 (0.9) |
| Inadequate cooperation during surgery | 28 (0.9) |
| Earlier glaucoma filtration surgery | 19 (0.6) |
| Earlier keratoplasty | 17 (0.5) |
| Posterior synechiae | 10 (0.3) |
| Anatomical differences in the body habitus | 2 (0.06) |
| Other complexities | 6 (0.2) |
Altogether, 2379 (72.7%), 816 (25.0%), and 77 (2.3%) surgeries involved topical, retrobulbar, and general anesthesia, respectively. Trypan blue dye staining of the anterior capsule was performed in 120 (3.7%) cases and iris hooks were used in 92 (2.8%) cases. Specialists (n=573, 96.0%) performed significantly more complex cataract surgeries (P<0.001) than residents (n=24, 4.0%).
The overall intraoperative complication rate was 5.4% (n=177; Table 2).
Table 2. Intraoperative complications during cataract surgery in the whole sample, in resident trainees, and in staff surgeons.
| Complication | Total (n=3272) | Resident trainee (n=241) | Staff surgeon (n=3031) |
| Posterior capsule tear | 85 (2.60) | 15 (6.22) | 70 (2.31) |
| Without vitreous loss | 31 (0.95) | 5 (2.07) | 26 (0.86) |
| With vitreous loss | 54 (1.65) | 10 (4.15) | 44 (1.45) |
| With dropped nucleus | 15 (0.46) | 5 (2.07) | 10 (0.33) |
| Anterior capsule tear | 50 (1.53) | 14 (5.81) | 36 (1.19) |
| Zonular fiber loss | 45 (1.38) | 8 (3.32) | 37 (1.22) |
| Intraocular lens dislocation | 3 (0.09) | 1 (0.41) | 2 (0.07) |
| Hyphema | 2 (0.06) | 0 | 2 (0.07) |
| Broken intraocular lens haptic | 1 (0.03) | 0 | 1 (0.03) |
| Expulsive bleeding | 1 (0.03) | 0 | 1 (0.03) |
n (%)
The intraoperative complication rate was significantly higher (P<0.001) among residents (n=33, 13.7%) than among specialists (n=144, 4.8%). The complication rate in simple cases was 5.3% (n=127), with intraoperative complication rates being significantly more common (P<0.001) in residents (n=29, 13.4%) than in specialists (n=98, 4.0%; Table 3).
Table 3. Intraoperative complications during cataract surgery in all simple cases and in simple cases for resident trainees and staff surgeons.
| Complication | Simple cases (n=2675) | Resident trainee (n=217) | Staff surgeon (n=2458) |
| Posterior capsule tear | 66 (2.47) | 15 (6.91) | 51 (2.07) |
| Without vitreous loss | 26 (0.97) | 5 (2.30) | 21 (0.85) |
| With vitreous loss | 40 (1.50) | 10 (4.61) | 30 (1.22) |
| With dropped nucleus | 13 (0.49) | 5 (2.30) | 8 (0.33) |
| Anterior capsule tear | 37 (1.38) | 12 (5.53) | 25 (1.02) |
| Zonular fiber loss | 26 (0.97) | 6 (2.76) | 20 (0.81) |
| Intraocular lens dislocation | 1 (0.04) | 0 | 1 (0.04) |
n (%)
The complication rate in complex cases was 8.4% (n=50) and was not significantly different (P=0.13) between residents (n=4, 16.7%) and specialists (n=46, 8.0%). The most common intraoperative complications were posterior capsule tear (PCT; n=85, 2.6%), PCT with vitreous loss (n=54, 1.65%), anterior capsule tear (ACT; n=50, 1.53%), and zonular fiber loss (n=45, 1.38%) in the whole study population. Anterior vitrectomy was performed in 58 (1.8%) cases and pars plana vitrectomy in 21 (0.6%) cases.
Among 241 surgeries performed by residents, 110 were completed with the involvement of a specialist (Figure 1).
Figure 1. Resident-specialist distribution of cataract surgeries in the whole study population.
The replacement of residents by specialists during phaco surgery occurred during phaco in 66 (60.0%), capsulorhexis in 21 (19.1%), irrigation/aspiration in 13 (11.8%), hydrodissection in 9 (8.2%), and IOL implantation in 1 case (0.9%).
Anterior vitrectomy and pars plana vitrectomy were more frequently (P<0.001) among resident cases (n=12, 5.0% and n=6, 2.5%, respectively) than in specialist cases (n=46, 1.5% and n=15, 0.5%, respectively).
In the whole study population, IOL was implanted in the capsular bag in 3169 (96.9%) and in the ciliary sulcus in 62 (1.9%) persons. Iris-claw IOL was fixed on the iris in 9 cases (0.3%), and 32 patients (0.9%) were left aphakic after the primary surgery. Significantly more patients (P<0.01) were left aphakic after the primary surgery performed by residents (n=7, 2.9%) when compared to primary surgery by specialists (n=25, 0.8%).
DISCUSSION
Cataract is a leading cause of visual impairment and phaco surgery is the most frequently performed intraocular surgery worldwide[11]–[12]. Almost 4.2 million phaco procedures were performed in Europe in 2015[13].
Cataract is usually an unavoidable side effect of aging[14]. Nearly one-third of people aged 65 years and over have visually significant cataract in Europe[15]. Phaco surgery is a relatively safe routine procedure with a low complication rate[13]. However, complications do occur and can cause severe visual impairment[16]–[17].
We analyzed the intraoperative complication rates for phaco surgery performed by specialists and residents and objectively determined the difficulty of each stage of the surgery at a tertiary eyecare center in Hungary. To the best of our knowledge, this is the first study to objectively report the order of difficulty in phaco surgery steps for residents. This is also the first study to report on intraoperative complication rates for primary phaco surgery, comparing specialists and residents in Hungary.
The overall intraoperative complication rate was 5.4% and was higher than that reported by other studies in Sweden (0.9%), Canada (1.8%), Portugal (4.1%), and Australia (4.9%)[4]–[6],[18]. Intraoperative complication rates for residents in this study was much higher (13.7%) compared to that reported by Low et al[5] in Canada (2.7%), Briszi et al[19] in Germany (3.8%), Fong et al[4] in Australia (6.1%), Oliveira-Ferreira et al[6] in Portugal (6.3%), and Ellis et al[20] in the USA (7.8%). Further, complication rates during phaco surgeries performed by specialists alone in Hungary (4.8%) were slightly higher compared to that reported in Australia (2.7%)[4] and Portugal (3.3%)[6]. Comparisons of intraoperative complication rates between residents and specialists showed different results in different countries. While Low et al[5] and Fong et al[4] did not find a significant difference between the two groups, our study and that of Oliveira-Ferreira et al[6] found significantly higher complication rates among residents during phaco surgery. Differences may be explained by the different numbers of phaco surgeries performed by residents during the residency program in different countries, because increased resident experience seems to decrease the incidence of intraoperative complications.
Phaco surgery is a cornerstone of the residency training worldwide[21]. While only 7.3% of all phaco surgeries involved residents in Hungary, studies from other industrialized countries reported much higher resident involvement rates (21%-64%)[1],[4]–[5],[22]. Our institution is the biggest and leading ophthalmic center in Hungary, and about 4 new residents begin their residency training every year in the clinic. The ophthalmology residency lasts for 5y and phaco surgery training begins in the second year. During the entire residency training, every resident performs 50 to 150 phaco surgeries at our institution, and this number may be associated with the lesser surgical experience compared to that in Canada, United Kingdom and Portugal where every resident performs 320 to 400 phaco surgeries on average during the same period[5]–[6],[23]. To ensure patient safety, specialists are allowed to swap the operating position with the resident during the surgery, in case of intraoperative complication or before predictable complication(s).
In the present study, the order and incidence of the most notable intraoperative complications were similar to findings from other studies as follows: PCT (2.6%), ACT (1.53%), zonular fiber loss (1.38%), and dropped nucleus (0.4%)[4]–[6]. The incidence of PCT (2.3%) and that of dropped nucleus among specialists (0.3%) were also similar to data from Canada and Portugal[5]–[6]. The incidence of ACT (5.81%) and PCT (6.22%) in residents was higher in our sample compared to that reported by Oliveira-Ferreira et al[6] from Portugal (ACT: 1.0%; PCT: 3.4%), Corey and Olson[24] and Bhagat et al[25] from the USA (PCT: 2.0% and 6.7%), and Low et al[5] from Canada (PCT: 0.8%). Dropped nucleus occurred also more frequently among residents in Hungary (2.0%) than in Germany (1.2%)[19], Portugal (0.6%)[6], and in the USA (0.6%)[26]. PCT and vitrectomy due to dropped nucleus are considered as a benchmark intraoperative complication[27]–[28], because they are associated with a higher incidence of postoperative endophthalmitis (8×) and retinal detachment (42×)[29].
The intraoperative complication rate also depends on case complexity[18]. Al-Jindan et al[30] reported that the complication rate may be twofold in complex cases, compared to that in simplex cases. To reduce the effect of complex cases on complication rates, we also analyzed the intraoperative complication rates in simple cases. The incidence rates showed similar values across the entire sample and compared to other studies with one exception, where the incidence of PCT among residents also showed a higher value (6.9%) as in the whole sample.
The most difficult steps of the phaco surgery, where the specialist took over the operation from the resident, were phaco (60.0%), capsulorhexis (19.1%), irrigation/aspiration (11.8%), and hydrodissection (8.2%). The difficulty of each stage of phaco surgery is of great interest. Knowing which part of the surgery poses the greatest complexity for residents would be useful to design training methods alongside to enhance the practice of those critical steps. Several authors subjectively evaluated the difficulty of each stage of phaco surgery among residents. Based on their results and similar to our results, residents found phaco, capsulorhexis, and irrigation/aspiration to be the most challenging parts of the surgery[9]–[10]. Based on the subjective and objective assessment of phaco surgery difficulties and the incidence of different complication rates among residents, phaco and capsulorhexis may be considered the most challenging steps in phaco surgery for residents.
In our curriculum, the number of phaco surgeries performed by residents during the 5y of residency is lower compared to published data from other developed countries. This is because our department places emphasis on theoretical knowledge prior to surgical skill in the first part of the training, after which the resident begins to perform a higher number of surgeries. This difference in the curriculum explains the disparity in the number of surgeries performed by specialists and residents.
The limitations of our study include its retrospective design, its involvement of only a single center, and the non-randomization of patients.
In conclusion, intraoperative complication rates were higher in residents than in specialists. Resident involvement into phaco surgery should be increased in our department in Hungary, in order to improve surgical confidence and acquire safe phaco techniques until the end of the residency. Objective assessment of difficulty stages in phaco surgery was in line with the subjective measurement of difficulty levels reported by other surveys, with the most challenging parts of phaco surgery being phaco and capsulorhexis.
Acknowledgments
Authors' contributions: Magyar M conducted the survey, analyzed the data, and wrote the article. Sándor GL and Ujváry L conducted the survey and analyzed the data. Nagy ZZ planned the survey and reviewed the manuscript. Tóth G designed the survey, and edited and reviewed the manuscript.
Conflicts of Interest: Magyar M, None; Sándor GL, None; Ujváry L, None; Nagy ZZ, None; Tóth G, None.
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