Keywords
vitreoretinal surgery - rhegmatogenous retinal detachment - Switzerland - fellowship
programme - pars-plana vitrectomy
Schlüsselwörter
vitreoretinale Chirurgie - rhegmatogene Netzhautablösung - Schweiz - Stipendienprogramm
- Pars-plana-Vitrektomie
Introduction
The journey to becoming a vitreoretinal (VR) surgeon is rigorous, involving extensive
training and progressive exposure to complex ocular surgeries [1]. Fellowship programmes play a pivotal role in this process by providing aspiring
surgeons with hands-on experience under expert supervision. However, during this period,
fellows are often tasked with performing surgeries independently or with varying levels
of supervision, which raises questions regarding surgical outcomes, patient safety,
and the fellowʼs learning curve [2]. To better understand the nuances of this transition from trainee to competent surgeon,
it is important to evaluate the performance and outcomes associated with surgeries
performed by fellows early in their training [3], [4].
The Swiss medical training system, known for its high standards of care, provides
a structured environment for surgical fellows. Fellows typically start with limited
responsibilities, gradually progressing to more complex procedures as they gain experience
[5]. However, with an estimated population of fewer than 9 million people, Switzerland
is a relatively small country compared to its neighbours such as Italy, France, and
Germany. For instance, if we assume an incidence of 1.4 in 10,000 for rhegmatogenous
retinal detachment (RRD) in Europe, this would result in fewer than 1,300 cases per
year in Switzerland [6]. This raises the following question: Is this enough to adequately train the next
generation of Swiss VR surgeons?
The purpose of this study was to evaluate baseline characteristics, intraoperative
choices, and surgical outcomes of patients operated by a single VR fellow during his
first 2 years of fellowship in the Swiss medical system. We believe that such a longitudinal
analysis is essential for assessing competency development in surgical fellows and
the associated patient outcomes, especially for VR surgery that is a specialised field
requiring extensive training and progressive acquisition of surgical skills.
Methods
Study design
The present study was a longitudinal, monocentric, retrospective study conducted at
a tertiary university centre (University Hospitals of Geneva). Written informed consent
was obtained from all patients included in the study. The study complies with the
tenets of the Declaration of Helsinki and was approved by the local ethical committee
(Swissethics, study number 2024-01359).
Study population
Results of all subsequent eyes presenting vitreoretinal diseases operated by standard
23- or 25-gauge pars-plana vitrectomy by the same VR fellow (G. E. B.), between January
2022 and March 2024 were analysed.
Baseline measurements
For each patient, the following demographics and clinical characteristics were recorded:
age, gender, ethnicity, diagnosis and ophthalmic/surgical history, best corrected
visual acuity (BCVA), and axial length. When possible, tomography (SD-OCT [Spectralis
OCT, Heidelberg Engineering AG, Germany]) and ultra-widefield fundus photography (Optos
California, Nikon Co. Ltd, Japan) were performed based on the vitreous and retinal
status a spectral-domain optical coherence.
Outcomes and measures
The primary outcome was the surgical success after any surgery. Loss of light perception,
serious irreversible complications, retinal re-detachment in case of primary RRD,
and any subsequent surgical interventions were considered surgical failure. Secondary
outcomes were the final BCVA at the final follow-up visit and the adverse events (AEs)
rate. Safety endpoints included the rate of intraoperative complications and post-operative
AEs during the entire follow-up period.
Statistical analysis
Descriptive statistics included mean and standard deviation (SD) for normally distributed
variables, and median and interquartile range (IQR) for non-normally distributed variables.
All tests were two-tailed, and a p-value of less than 0.05 was considered statistically
significant. Statistical analyses were performed with commercially available software
(Stata version 13.1; StataCorp, College Station, TX, USA).
Results
Baseline characteristics of study population and type of surgeries
One-hundred eyes in 89 patients were included (65 men and 24 women, mean age 61.5 ± 16.1
years, range 22 – 94 years). Out of those 100 pars-plana vitrectomies, 38.0% were
operated by the fellow with the supervisor being present in the operating theatre
but not sitting at the microscope and not directly assisting (group A), 36.0% were
operated under the direct observation of the supervisor who was sitting at the microscope
next to the fellow providing close guidance (group B), and in 26.0% of the eyes, the
fellow was able to perform only some parts of the surgery based on his competence
at that time, while the rest was completed by the supervisor (group C).
The main type of surgery performed was vitrectomy for rhegmatogenous retinal detachment
(52.0%; n = 52) followed by silicone oil removal (13.0%), endophthalmitis (8.0%),
epiretinal membrane peeling (8.0%), secondary intraocular lens (7.0%), trauma (5.0%),
diabetic haemorrhage or tractional retinal detachment (4.0%), full-thickness macular
hole (2.0%), and vitreous haemorrhage (1%). Out of all surgeries, 58.0% were classified
as emergencies (mostly RRD, endophthalmitis and trauma) and 42.0% as elective. Eighty-three
surgeries were standalone vitrectomies, while 17 were combined with cataract surgery.
Baseline characteristics of the study patients are summarised in [Table 1].
Table 1 Baseline demographics and clinical characteristics of study population and type of
surgery performed.
|
Demographic and clinical data
|
Mean ± SD (%)
|
|
RRD: rhegmatogenous retinal detachment; SO: silicone oil; ERM: epiretinal membrane;
IOL: intraocular lens; TRD: tractional retinal detachment; FTMH: full thickness macula
hole; PPV: pars-plana vitrectomy; BCVA: best-corrected visual acuity
|
|
Age (years)
|
61.5 ± 16.1
|
|
|
22 – 94
|
|
Male gender
|
65 (65.0%)
|
|
Ethnicity
|
|
|
|
92 (92.0%)
|
|
|
6 (6.0%)
|
|
|
2 (2.0%)
|
|
Bilateral cases
|
11 (11.0%)
|
|
Diagnosis
|
|
|
|
52 (52.0%)
|
|
|
13 (13.0%)
|
|
|
8 (8.0%)
|
|
|
8 (8.0%)
|
|
|
7 (7.0%)
|
|
|
5 (5.0%)
|
|
|
4 (4.0%)
|
|
|
2 (2.0%)
|
|
|
1 (1.0%)
|
|
Emergency surgeries
|
58 (58.0%)
|
|
Elective surgeries
|
42 (42.0%)
|
|
Standalone PPV
|
83 (83.0%)
|
|
Combined surgeries
|
17 (17.0%)
|
|
Group A
|
38 (38.0%)
|
|
Group B
|
36 (36.0%)
|
|
Group C
|
26 (26.0%)
|
|
Baseline BCVA (decimal)
|
0.32 ± 0.34
|
Characteristics of the subgroup of vitrectomies for rhegmatogenous retinal detachment
In the group of vitrectomy for RRD, the most frequent surgery performed, 48.1% of
the surgeries belonged to group A, while the rest was split between groups B and C.
Forty eyes (79.6%) were classified as recent and uncomplicated RRD, while 12 (23.1%)
were classified as long-standing or complicated RRD. Most of the RRD cases were macula-on
(59.6%; n = 31) and phakic (69.2%; n = 36). In order to manage RRD, perfluorocarbon
liquid was used in 40.4% of the eyes, and retinotomy was performed in 26.9% of the
cases. Thirty-four patients (65.4%) required a 360° laser retinopexy and ab-externo
cryocoagulation of the retinal tears. The most used endotamponade for RRD surgery
was 14% C3F8 gas (42.3%; n = 22), followed by 20% SF6 gas (26.9%; n = 14), heavy silicone
oil (13.5%; n = 7); 1,000 cSt silicone oil (9.7%; n = 5), and 5,000 cSt silicone oil
(3.9%; n = 2). Characteristics of the RRD group are summarised in [Table 2].
Table 2 Clinical characteristics of the rhegmatogenous retinal detachment subgroup.
|
Clinical data
|
Mean ± SD (%)
|
|
RRD: rhegmatogenous retinal detachment; SO: silicone oil
|
|
Type of RRD
|
|
|
|
40 (79.6%)
|
|
|
12 (23.1%)
|
|
Macula status
|
31 (59.6%)
|
|
|
21 (40.4)
|
|
Lens status
|
|
|
|
36 (69.2%)
|
|
|
16 (30.8%)
|
|
Endotamponade
|
|
|
|
22 (42.3%)
|
|
|
14 (26.9%)
|
|
|
7 (13.5%)
|
|
|
5 (9.7%)
|
|
|
2 (3.9%)
|
Primary outcome: surgical success
Out of all eyes, surgical success was 96% with only four eyes (4.0%) classified as
failure requiring a subsequent surgery. All of those belonged to the RRD group and
required subsequent surgical intervention because of a recurrent detachment.
Secondary outcomes
Out of all surgeries, mean BCVA improved significantly during follow-up (0.32 ± 0.34
decimals at baseline vs. 0.47 ± 0.30 decimals at final follow-up; p < 0.05). No intraoperative
complications were noted among the studied cohort. None of the combined procedures
were associated with posterior capsule rupture or the need for anterior vitrectomy.
All pars-plana vitrectomies were uneventful and without peri-operative complications.
The most frequent AE was post-operative cystoid macular oedema that occurred in 4.0%
of the eyes, and cataract development that occurred in almost all patients who were
phakic at the time of surgery. One patient operated using 23-gauge vitrectomy experienced
a lens touch during the surgery for RRD and developed a white cataract at post-operative
follow-up. Average follow-up time was 5.5 ± 5.4 months (range 1 – 24 months). Primary
and secondary outcomes are summarised in [Table 3].
Table 3 Primary and secondary outcomes.
|
Outcome
|
Mean ± SD (%)
|
|
BCVA: best corrected visual acuity; AE: adverse events; CMO: cystoid macular oedema
|
|
Surgical success
|
96 (96.0%)
|
|
Surgical failure
|
4 (4.0%)
|
|
BCVA at final follow-up (decimals)
|
0.47 ± 0.30
|
|
Post-operative AEs
|
|
|
|
4 (4.0%)
|
|
|
4 (4.0%)
|
|
|
1 (1.0%)
|
Discussion
The present study aimed to assess the surgical outcomes and intraoperative experiences
of a single VR fellow during his first two years of training in the Swiss medical
training system. Most surgeries, particularly those for rhegmatogenous retinal detachment,
resulted in successful outcomes with marked post-operative improvements in visual
acuity. The strength of this study is that the training environment was structured
with the fellow and the supervisors collaborating in various capacities. At the time,
the VR fellow was the only VR surgeon in training within the fellowship programme
and participated in the on-call retinal surgery rotation, which included three retinal
surgeons in total, resulting in being on call for more than 120 days per year. This
allowed the recruitment of 58 emergency cases (including RRD, endophthalmitis and
trauma cases) where a pars-plana vitrectomy was required. As a result, the fellow
performed 100 vitrectomies over two years of training, likely
because supervisors tend to be more comfortable allowing fellows to operate in emergencies
rather than elective cases. A study performed in the United Kingdom (UK) showed that
it was safe for experienced VR fellows to perform surgery during weekends and holidays,
supervised or unsupervised, as they had similar success rates and visual outcomes
to more experienced surgeons [2].
There are no official requirements for the completion of a VR surgery programme in
Switzerland, while in the United States (US), the Association of University Professors
of Ophthalmology (AUPO) guidelines for VR fellowships require that the fellow performs
or assists at a minimum of 40 scleral buckles and 100 vitrectomies [1]. Although performing 40 scleral buckles is almost impossible during training in
Switzerland, as this procedure is nowadays rarely performed, the requirements regarding
vitrectomies were achieved in a two-year period in our study. However, fellows in
the US most commonly perform 300 to 400 vitrectomies [1]. In the UK, the British & Eire Association of Vitreoretinal Surgeons (BEAVRS) requires
the completion of at least 250 vitrectomies to become a consultant VR surgeon, a number
that is probably difficult to achieved in a 2-year Swiss fellowship programme due
to the low case volume [7]. In a survey that assessed the experience of VR fellows in the UK, an average of
351 vitrectomies were performed during the fellowship [8]. According to the same survey, most cases were vitrectomies for retinal detachment
as in our study, but the fellows also performed a much greater number of vitrectomies
for epiretinal membranes peels (76 in the UK versus 8 in this study) and diabetic
delamination (16 in the UK versus 4 in this study) [8].
The success rate of vitrectomy for RRD in this study was 96%. This is much higher
than the 70% success rate of less experienced surgeons reported by Dugas et al. in
a French study [9]. In a similar study of Radeck et al. performed in Germany, the success rate of inexperienced
surgeons was about 80% and was stabilised at more than 90% only after performing 200
vitrectomies [10]. Keller et al. also showed that surgeons in training saw a recurrent retinal detachment
rate of 14.7% during their learning curve [11]. On the contrary, the results of our study were more similar to those of Mazinani
et al., who reported a success rate of 90%; interestingly, this was not related to
the number of vitreoretinal procedures performed [3].
The relatively low re-detachment rate in this study could be explained by the fact
that the fellow in training was directly supervised in most of surgeries, as only
38% of surgeries were performed with the supervisor attending not sitting at the microscope.
As shown by Masson et al., surgeons in training can reach similar visual outcomes
and complication rates than experienced surgeons under proper supervision [4]. In addition, all patients were operated under deep sedation or general anaesthesia
according to the departmentʼs usual practice. This probably allows better communication
in the operating room between the fellow and the supervisor and facilitates guidance
of the surgeon in training.
The conservative approach of the fellow with the frequent use of 14% C3F8 gas as endotamponade (used in 42.3% of RRD) and the common application of 360° laser
retinopexy and ab-externo cryocoagulation (in 65.4% of RRD) may have also contributed
to the high success rate. It is possible that a more experienced surgeon would more
frequently use a 20% SF6 gas versus 14% C3F8 gas and would more often prefer gas over silicon oil as endotamponade compared to
a young surgeon in training.
Out of 100 vitrectomies, the fellow also took on some cases considered more challenging
by young surgeons such us ocular trauma requiring vitrectomy (5%), secondary intraocular
lens implantation (7%), and diabetic tractional retinal detachment (4%). Due to their
small number, the success rate of those procedures cannot be evaluated. However, it
is important for fellows to perform such types of surgeries as well, as it is has
been shown that, in diabetic tractional retinal detachment for example, the anatomical
success rates increases from 85% to 96% from the first to second year of training
[12].
Several additional reasons could contribute to the high success rate observed in this
study. The fellow had the opportunity to assist many VR surgeries during his residency
before starting his hands-on experience. Moreover, he was also trained in cataract
and glaucoma surgery before the VR fellowship. While Thomsen et al. demonstrated that
surgical skills gained during cataract surgery training donʼt necessarily enhance
vitreoretinal surgery performance, we believe that any opportunity to perform intraocular
surgery can improve a traineeʼs dexterity and boost their confidence [13]. Watching multiple surgical videos is also known to promote surgical planning, add
to skills improvement, and facilitate situational awareness during vitreoretinal surgery
[14]. The recent availability of three-dimensional (3D) videos could further enhance
the teaching efficiency of training in intraocular surgery [15]. The importance of the availability of mentors that are committed in training, dedicating
time in supervising fellows, and giving them the opportunity to operate should also
not be underestimated [16]. Although not used in this study, a 3D heads-up display has been shown to promote
surgical training, and we believe that it could be extremely helpful in fellowship
programmes [17], [18].
Finally, another tool that could be used for the training of fellows in countries
with low patient volumes like Switzerland is a surgery simulator. The fellow in this
study completed the cataract and vitreoretinal surgery training programme of the Eyesi
surgical simulator (VRMagic, Haag-Streit, Switzerland) prior to the beginning of the
fellowship. Surgical simulators are considered one of the best training tools for
inexperienced surgeons and the skills acquired while using them are thought to be
directly transferred to the operating theatre [19]. They can also be used to evaluate the surgical competence of fellows before operating
on patients and they can probably help identify surgical steps where more training
is needed [20]. In low volume fellowship programmes, they can also be used by the fellows for “warming
up” before surgery [21]. Unfortunately, their use is limited by high costs,
which make surgical simulators unavailable in most centres, and by the lack of time
of fellows, who are unable to take full advantage of them even when accessible [19], [22].
The present study has several limitations. First, it was not a prospective randomised
controlled comparative study and there was no control group. The fact that all cases
were operated by the same VR fellow at a single tertiary university centre, may be
considered as both a limitation or a strength. This led to some degree of standardisation
in surgical techniques and clinical decisions; however, some aspects of patient management
inherently depend on the surgeonsʼ own experience and judgement. As a result, the
findings likely reflect only this particular fellowʼs experience and may not be generalisable.
Moreover, in this study, vitrectomy was the sole treatment performed for RRD, as it
is the gold standard at the institution. However, alternative procedures such as scleral
buckle, pneumatic retinopexy (PnR), or viscopexy could have been considered for many
of the cases. While PnR is an established and effective method for treating certain
types of RRD, it is not yet widely
practiced in Switzerland. The future adoption of this technique could potentially
decrease the number of vitrectomies performed by fellows [23]. That said, the limited use of PnR by fellows is not unique to Switzerland, as a
2019 study revealed that in the US, as of 2016, the median number of PnR procedures
performed by VR fellows per year was just 7 [24]. Finally, another limitation of our study is that it was conducted in a predominantly
homogenous (western) population.
In conclusion, this study offers an in-depth assessment of the surgical outcomes and
intraoperative experiences of a vitreoretinal fellow during his first two years of
fellowship in Switzerland. Most surgeries, particularly those for rhegmatogenous retinal
detachment, resulted in successful outcomes with marked post-operative improvements
in visual acuity. The training environment was structured with the fellow and the
supervisors collaborating in various capacities ranging from direct supervision to
independent practice. Although some complications were encountered, our findings highlight
the programmeʼs effectiveness in developing essential surgical skills and delivering
positive patient outcomes in vitreoretinal surgery.
