10.14639/0392-100X-N1946
Objective. The aim of this study is to evaluate the feasibility of the 3D exoscope in a microvascular anastomosis training setting and compare it with the gold-standard technique using the operating microscope (OM). Methods. Participants were recruited among otorhinolaryngology head and neck surgery (OHNS) residents of two tertiary care hospitals. Trainees were asked to complete 4 microvascular end-to-end anastomoses on chicken thighs with the OM and VITOM 3D exoscope. The performances were scored by experienced microvascular surgeons; an objective evaluation of the anastomosis and a subjective assessment of the workload were conducted. Results. 8 OHNS residents were recruited. Considering the amount of time needed to complete (TTC) the anastomosis, an improvement was shown by all the participants throughout the training program. The objective evaluation of the anastomosis did not show a significant difference. No significant differences were found by analyzing the subjective workload with the different tools. Conclusions. This article represents the first attempt to compare the use of the OM and the 3D exoscope during training for microsurgery. The results of our study demonstrate the noninferiority of microsurgical training obtained using the 3D exoscope compared to that offered by the OM.
text/xml
1827-675X
1946
en
Daniele Marchioni
http://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
3D exoscope
Microsurgical training using an ex-vivo model: microscope vs 3D exoscope
Text.Serial.Journal
https://www.actaitalica.it/
42
Head and neck
2022-06-30
2021-11-30
2022-07-26
2022-07-26
223-229
1
Daniele Marchioni
2022/06/30
10.14639/0392-100X-N1946
223
Otorhinolaryngology Head and Neck Surgery Department, University Hospital of Modena, Modena, Italy
1827-675X
3D exoscope
en
229
Microsurgical training using an ex-vivo model: microscope vs 3D exoscope
https://www.actaitalica.it/article/download/1946/818
42
ACTA OTORHINOLARYNGOLOGICA ITALICA 2022;42:223-229; doi: 10.14639/0392-100X-N1946




Head and neck


Microsurgical training using an ex-vivo model:
microscope vs 3D exoscope
Training microchirurgico su modello ex-vivo: microscopio vs esoscopio 3D
Gabriele Molteni1,2, Michael Ghirelli3, Andrea Sacchetto4, Matteo Fermi5,6, Stefano De Rossi7, Francesco Mattioli3,
Livio Presutti5,6, Daniele Marchioni3
1
 Otolaryngology, Head and Neck Department, University Hospital of Verona, Verona, Italy; 2 Otolaryngology, Department of Surgery,
Dentistry and Pediatrics, University of Verona, Italy; 3 Otorhinolaryngology Head and Neck Surgery Department, University Hospital
of Modena, Modena, Italy; 4 Department of Otolaryngology, Ospedale San Bortolo, AULSS 8 Berica, Vicenza, Italy; 5 Department of
Otorhinolaryngology Head and Neck Surgery, Azienda Ospedaliero-Universitaria di Bologna IRCCS, Policlinico Sant’Orsola-Malpighi,
Bologna, Italy; 6 Department of Experimental, Diagnostic and Specialty Medicine, Alma Mater Studiorum - University of Bologna,
Bologna, Italy; 7 Department of ENT & H&N Surgery, Mater Salutis Hospital, AULSS 9 Scaligera, Verona, Italy


SUMMARY
Objective. The aim of this study is to evaluate the feasibility of the 3D exoscope in a mi-
crovascular anastomosis training setting and compare it with the gold-standard technique
using the operating microscope (OM).
Methods. Participants were recruited among otorhinolaryngology head and neck surgery
(OHNS) residents of two tertiary care hospitals. Trainees were asked to complete 4 micro-
vascular end-to-end anastomoses on chicken thighs with the OM and VITOM 3D exoscope.
The performances were scored by experienced microvascular surgeons; an objective eva-
luation of the anastomosis and a subjective assessment of the workload were conducted.
Results. 8 OHNS residents were recruited. Considering the amount of time needed to com-
plete (TTC) the anastomosis, an improvement was shown by all the participants throughout
the training program. The objective evaluation of the anastomosis did not show a signifi-
cant difference. No significant differences were found by analyzing the subjective workload
with the different tools.                                                                           Received: November 30, 2021
Conclusions. This article represents the first attempt to compare the use of the OM and the 3D      Accepted: February 19, 2022
exoscope during training for microsurgery. The results of our study demonstrate the noninferiori-
ty of microsurgical training obtained using the 3D exoscope compared to that offered by the OM.     Correspondence
                                                                                                    Andrea Sacchetto
KEY WORDS: microsurgery, microsurgical training, microvascular anastomosis, optic
                                                                                                    Division of Otorhinolaryngology, Department of
microscope, 3D exoscope                                                                             Surgery, Dentistry, Gynecology, and Pediatrics,
                                                                                                    University of Verona, University Hospital of Vero-
RIASSUNTO                                                                                           na, piazzale Aristide Stefani 1, 37126 Verona, Italy
Obiettivo. Lo scopo di questo studio è quello di valutare l’applicabilità dell’esoscopio 3D         Tel. +39 045 8122330. Fax +39 045 8122313
                                                                                                    E-mail: andrea.sacchetto89@gmail.com
nel training su anastomosi microvascolari e confrontarlo con la tecnica gold-standard,
utilizzando il MO.
Metodi. I partecipanti sono stati reclutati tra medici in formazione in Otorinolaringoiatria          How to cite this article: Molteni G, Ghirelli M,
di due ospedali di terzo livello. È stato chiesto loro di completare 4 anastomosi microvasco-         Sacchetto A, et al. Microsurgical training using
lari termino-terminali su peduncolo ischiatico di pollo con MO ed esoscopio VITOM® 3D.                an ex-vivo model: microscope vs 3D exoscope.
Le prestazioni sono state valutate da chirurghi microvascolari esperti; è stata condotta una          Acta Otorhinolaryngol Ital 2022;42:223-229. htt-
valutazione oggettiva dell’anastomosi e una valutazione soggettiva del carico di lavoro.              ps://doi.org/10.14639/0392-100X-N1946
Risultati. Hanno partecipato otto medici in formazione. Tutti i partecipanti hanno mostrato
                                                                                                    © Società Italiana di Otorinolaringoiatria
un progressivo miglioramento nel tempo di completamento dell’anastomosi. La valutazione             e Chirurgia Cervico-Facciale
oggettiva delle anastomosi non ha mostrato differenze significative. Nessuna differenza sta-
tisticamente significativa è stata trovata analizzando il carico di lavoro soggettivo.
                                                                                                                   OPEN ACCESS
Conclusioni. Questo studio rappresenta il primo tentativo di confrontare l’uso del MO e
dell’esoscopio 3D durante il training per la microchirurgia. I risultati del nostro studio          This is an open access article distributed in accordance with
                                                                                                    the CC-BY-NC-ND (Creative Commons Attribution-Non-
dimostrano la non inferiorità della preparazione microchirurgica ottenuta con l’esoscopio           Commercial-NoDerivatives 4.0 International) license. The
3D rispetto a quella offerta dal MO.                                                                article can be used by giving appropriate credit and mentio-
                                                                                                    ning the license, but only for non-commercial purposes and
PAROLE CHIAVE: microchirurgia, training microchirurgico, anastomosi microvascolare,                 only in the original version. For further information: https://
microscopio ottico, esoscopio 3D                                                                    creativecommons.org/licenses/by-nc-nd/4.0/deed.en




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G. Molteni et al.




Introduction                                                   versity Hospital of Verona, Italy). Given its experimental
                                                               setting, this study was granted exempt status by the insti-
Traditionally, surgical skills are developed and refined in
                                                               tutional review board of both institutions. The fundamen-
the operating room under the direct observation of a super-
                                                               tal prerequisite was attendance to one of the introductory
vising experienced surgeon 1. However, focus on prevention
                                                               courses in microvascular and nervous anastomosis organ-
of adverse outcomes and operating room efficiency have
                                                               ised by the Italian Society of Microsurgery, where trainees
made it more difficult for residents to acquire microsurgi-
cal skills. The potentially catastrophic complications as-     learn the basics of microvascular surgery, and familiarise
sociated with failed microvascular or nervous anastomosis      themselves with microsurgical tools and microscope. Dur-
and a steep learning curve make it difficult for trainees to   ing the course, basic microsurgical technique is practiced
obtain consistent hands-on training without attending dedi-    on latex gloves and ex-vivo animal tissues, such as the
cated courses on microsurgical techniques. These aspects       chicken thigh model.
make the ex-vivo models ideal for training. Many different
models have been proposed for surgical training in micro-      Model
surgery 2. The chicken thigh model is a viable option due      Chicken thighs were used as ex-vivo model for the pur-
to the calibre of the anastomosis which is similar to head     pose of this study. The ischiatic neurovascular bundle was
and neck vessels 3. Other authors demonstrated its useful-     identified under the iliotibialis and iliofibularis muscles. A
ness in improving surgical skills for microvascular anas-      microvascular instrument set, consisting of a needle holder
tomosis using a standard operating microscope (OM) 3,4.        (14 cm), dissecting scissors (15 cm), forceps (11 cm), ad-
The OM provides magnification and lighting that allows         ventitia scissors (15 cm), vessel dilator (11 cm) and vessel
microdissection of critical structures and is the workhorse    approximator clamp, was provided. An OM used routinely
for nervous and microvascular anastomosis. However, the        for microsurgical activities in operating room, with record-
OM presents some disadvantages, including limited focal        ing capability, was available. A VITOM® 3D exoscope
range and poor ergonomics. In the last years, the exoscope     (Karl Storz, Tuttlingen, Germany) was temporarily pro-
was developed as a new hybrid between the OM and the           vided at both institutions to complete the training program.
endoscope. An exoscope consists of a high-definition video     Trainees were asked to complete 4 microvascular end-to-
telescope connected to an operating monitor which allows       end anastomoses (2 arteries and 2 veins) on ischiatic ves-
visualisation of a wide portion of the operating field along   sels using the OM and the VITOM® 3D exoscope, as shown
with the possibility of magnification. The main advantages     in Figure 1. Trainees were randomly assigned to the OM
offered by this instrument are the reduced need for reposi-    and VITOM® 3D exoscope to start with; they performed 4
tioning of the field of view during surgery compared to the    consecutive anastomoses with OM or the VITOM® 3D exo-
OM, as well as improved ergonomics. However, the need          scope and then with the other tool. Four candidates started
of a second operating monitor for the assistant surgeon        with OM, and the remaining four candidates started with
during microvascular anastomosis needs to be considered.       the VITOM® 3D exoscope. After completing each anasto-
Different authors have already reported its applicability in   mosis, participants were asked to cut out the sutured seg-
skull base surgery, neurosurgery and abdominal surgery 5-7.    ment to show the lumen in order to obtain evaluation from
Recently, several authors also published their experiences     the assessor (G.M., F.M.).
with this technology in head and neck reconstructive sur-
gery 8-10. Moreover, the educational potential of this tech-
                                                               Instruments
nology for microsurgical skills acquisition in comparison
                                                               The exoscopic system is an evolution of 2D system and
with the OM has not yet been assessed. The aim of this
                                                               consists of a camera placed above the surgical field with
study is to evaluate the safety and accuracy of 3D exoscope
                                                               the aid of a holding arm and a high definition 3D moni-
in microvascular anastomosis training setting and compare
                                                               tor. A pilot is placed next to the surgeon that enables him/
it with the gold-standard technique using the OM.
                                                               her to zoom in and out and focus the surgical field with
                                                               a remote control. Surgery is performed by looking at the
Materials and methods                                          3D monitor positioned in front of the surgeon while us-
Subjects                                                       ing appropriate glasses. In our study, a VITOM® 3D exo-
We conducted a prospective study with a pre-defined proto-     scope (Karl Storz GmbH, Tuttlingen, Germany) was used,
col. Participants were recruited from otorhinolaryngology      as shown in Figure 1. The participants utilised a standard
head and neck surgery (OHNS) residents of two tertiary         OPMI LUMERA® (Carl Zeiss Meditec, Jena, Germany)
care hospitals (University Hospital of Modena and Uni-         OM, which is available in the operating room (Fig. 2).



224
                                                                                               Microsurgical training: microscope vs exoscope 3D




                                                                           from the minimum score of 1 to the maximum score of 5).
                                                                           Subjective evaluation of the workload was calculated with
                                                                           a 10-item questionnaire; subjective analysis was performed
                                                                           by completing a comprehensive 5-point Likert scale survey
                                                                           to evaluate the performance after each phase of the training
                                                                           (e.g. OM vs VITOM® 3D exoscope).
                                                                           Statistical analysis was performed with GraphPad Prism 7
                                                                           for Mac OS X (GraphPad Software Inc, La Jolla, CA). The
                                                                           normality of data distribution was assessed with Kolmog-
                                                                           orov-Smirnov test. Continuous variables were presented
                                                                           as mean (± SD) or median (IQR), as appropriate, while
                                                                           categorical variables were presented as percentages. Chi-
                                                                           square test (or Fisher’s exact test) and Mann Whitney U
                                                                           test were used to assess the association among categorical
                                                                           variables (e.g., mistakes made by the trainees within the
Figure 1. Setting of training room during microvascular anastomosis with
                                                                           different subgroups OM vs VITOM® 3D exoscope). Two-
VITOM® 3D.
                                                                           tailed Student T test analyses were performed to compare
                                                                           means of the continuous variables among groups. Statisti-
                                                                           cal significance was set at p < 0.05.

                                                                           Results
                                                                           Participants in the present study comprised 1 female and 7
                                                                           male OHNS residents. Four residents were recruited from
                                                                           each hospital (Hospital of Verona and Hospital of Modena)
                                                                           and participated in the study at their hospital of origin. All
                                                                           were right-hand dominant, and age ranged from 28 to 33
                                                                           years old, being postgraduate year PGY-3 or PGY-4.
                                                                           The mean TTC of the first arterial anastomosis was 31.9 min-
                                                                           utes (SD ± 9.1) with OM and 31.8 minutes (SD ± 5.3) with VI-
                                                                           TOM® 3D exoscope, while for the second arterial anastomosis
                                                                           the mean TTC was 27 minutes (SD ± 4.6) with OM and 26.3
                                                                           minutes (SD ± 5.4) with VITOM® 3D. The first venous anas-
Figure 2. Setting of training room during microvascular anastomosis with   tomosis was completed on average in 29.1 minutes (SD ± 7.5)
operative microscope.                                                      with OM and 34.5 minutes (SD ± 11.1)with VITOM® 3D; the
                                                                           second venous anastomosis in 25.1 minutes (SD ± 7.1) with
                                                                           OM and 28.4 minutes (SD ± 6.5)with VITOM® 3D. Consider-
Assessment and statistical analysis                                        ing the amount of time needed to complete the microvascular
The video-recorded performances were independently                         anastomosis, an absolute reduction in mean TTC was seen by
scored by two experienced microvascular staff surgeons                     all participants throughout the training program; a significant
(G.M. and F.M.), who were blinded to the subject per-                      difference was reached only comparing the TTC of first and
forming the task. Main outcome measures were the time to                   second arterial anastomosis performed with VITOM® 3D
completion (TTC) of the anastomosis and evaluation of the                  (p = 0.04), as shown in Table I.
quality of the anastomosis, through a specific assessment                  The results of the evaluation of the quality of the anasto-
tool which takes into account the following microsurgical                  mosis are summarised in Table II; we observed an abso-
aspects: equidistance of stitches, intimal flap, transfixed                lute improvement of mean scores after almost all the steps,
stitch, intraluminal tails and vascular lesion. TTC of the                 with the exception of the arterial anastomosis with the OM,
anastomosis began at the start of positioning of the first                 where a worsening of the mean performance was noticed
stitch and ended by completing the tying of the last stitch.               (mean overall evaluation 3.0 at first attempt vs 2.9 at second
The assessors evaluated different aspects of the microvas-                 attempt). However, no significant differences were seen, as
cular anastomosis to give a final overall result (ranging                  shown in Table II.



                                                                                                                                           225
G. Molteni et al.




Table I. Mean time to complete the anastomosis.
                                         TTC anastomosis Microscope                 TTC anastomosis VITOM 3D              P-value
                                                   (min)                                      (min)
 Artery 1                                               31.9                                  31.8                         0.97
 Artery 2                                               27.0                                  26.3                         0.77
 P-value                                                0.09                                  0.04
 Vein 1                                                 29.1                                  34.5                         0.27
 Vein 2                                                 25.1                                  28.4                         0.36
 P-value                                                0.07                                  0.09
TTC: time to complete.



Table II. Objective evaluation of the quality of the anastomosis.
                                                       Microscope                          VITOM 3D                       P-value
 Artery 1                                               3.0                                   3.3                          0.35
 Artery 2                                               2.9                                   3.5                          0.27
 P-value                                                0.76                                  0.59
 Vein 1                                                 2.4                                   3.1                          0.14
 Vein 2                                                 3.1                                   3.3                          0.78
 P-value                                                0.08                                  0.81



A subanalysis was performed to ascertain if specific micro-                    for various specialties, including reconstructive procedures
surgical mistakes occurred more frequently in one group or                     in head and neck surgery. The acquisition of advanced mi-
the other. It was found that lack of equidistance of stitches                  crosurgical skills is obtained through a long training that is
and presence of lesion to the vessel were more frequent                        traditionally performed on ex-vivo models with the aid of
in the OM group, even if Fisher’s exact test did not reach                     the OM. The chicken model is one of the most widespread
statistical significance (p = 0.31 and p = 0.35, respectively)                 options in microsurgical training, as it allows trainees to
(Tab. III). Finally, the results of the subjective assessment                  safely reproduce the surgical gesture on arteries and veins
with the 5-point Likert scale are shown in Table IV. The two                   whose calibre are comparable to that of head and neck ves-
tools obtained similar scores in the majority of the items;                    sels 3. The OM is currently the gold standard for micro-
larger differences were observed for the item “depth of                        vascular surgery; however, in recent years, the use of an
field” (4 ± 0.3 SEM for OM vs 3.1 ± 0.3 SEM for VITOM®                         exoscope in microsurgery is rapidly spreading. In particu-
3D – p = 0.06) and for the item “precision and quickness in                    lar, experience has been gathered regarding the compari-
handling the needle” (2.9 ± 0.2 SEM for OM vs 3.5 ± 0.3                        son between microsurgical procedures or steps of surgery
SEM for VITOM® 3D – p = 0.09). Nevertheless, no signifi-                       conducted using the 3D exoscope and OM, especially in
cant differences were seen.                                                    the field of neurosurgery 11,12. Moreover, Belykh et al. 13 de-
                                                                               scribed the comparison between the 2D Exoscope, 3D exo-
                                                                               scope and 3D endoscope for microvascular anastomosis in
Discussion                                                                     neurosurgery. Aside from experimental settings, the use of
Surgical training for microvascular surgery is fundamental                     the 3D exoscope as a substitute for OM or as an additional


Table III. Comparison between different aspects of the microvascular anastomosis.
                                                    Microscope                             VITOM 3D                       P-value
 Equidistance                                            17                                   12                           0.3
 Intimal flap                                             7                                    6                          > 0.99
 Transfixed stitches                                      2                                    3                          > 0.99
 Intraluminal ends                                        5                                    5                          > 0.99
 Vascular lesion                                          4                                    1                           0.3




226
                                                                                                   Microsurgical training: microscope vs exoscope 3D




Table IV. Subjective evaluation of the workload and comparison between OM and VITOM 3D results.
                                                                      Microscope                  VITOM 3D                      P-value
Ergonomics                                                               3.75                       3.5                           0.59
Neck pain                                                                1.75                       2.5                           0.12
Back pain                                                               1.625                       1.25                          0.25
Focus                                                                    4.25                       4.25                         > 0.99
Depth of field                                                           4.0                       3.125                          0.06
Headache                                                                 1.25                       1.5                           0.43
Tremor                                                                  2.125                       1.75                          0.47
Precision and quickness in handling the vessels                         3.625                       3.75                          0.76
Precision and quickness in positioning the stitches                     2.875                       3.5                           0.09
Overall satisfaction                                                     3.5                        3.5                          > 0.99



tool during microscopic procedures has been described re-                    However, several studies have assessed the effectiveness of
cently in the fields of paediatric and urologic surgery 7, as                3D visualisation methods. The authors reported excellent
well as in neurosurgery 6,14-16.                                             comfort from surgeons in the use of these tools, particu-
The results of our study found no significant differences                    larly in relation with the ease of use with reduced muscles
between either surgical items (i.e. surgical time and pre-                   fatigue due to the chance to assume a more ergonomic posi-
cision in the execution of the anastomosis) or subjective                    tion during surgery. In addition, the potential didactic role,
ones. It is necessary, however, to underline some essential                  based on the possibility to screen images similarly to the
points to analyse the results.                                               OM, was highlighted.
The surgeons enrolled for the study attended a microsurgi-                   Nevertheless, Wong et al. 20 and Kotsougiani et al. 21 report-
cal course of the Italian society of microsurgery. This re-                  ed an increase in anastomosis times related to low quality
quires at least 20 hours of microsurgical practice with OM                   of the image. In contrast, Palumbo et al. 22 and Liu et al. 23
on an ex-vivo or synthetic model.                                            showed that surgical times were comparable to the OM or a
In addition, the OM is used by residents during otologi-                     progressive improvement of this parameter.
cal surgery procedures and related training. Therefore, the                  Nonetheless, a more precise definition of the advantages
participants already had sufficient experience with the mi-                  and disadvantages to the use of 3D exoscopes compared to
crosurgery technique performed with the OM and did not                       the OM in such procedures is still needed. Ex-vivo animal
require any period of adaptation to its use. On the other                    models are particularly useful for this purpose, given their
hand, the exoscope is not routinely used by residents; its                   prompt availability and safety.
diffusion at the moment is still limited to a few hospitals                  In our study, since statistical significance was not reached
and its use is also limited to a small number of surgical pro-               in any of the domains analysed, the 3D exoscope showed
cedures. As far as otorhinolaryngology is concerned, only                    noninferiority compared with the OM for the training of
limited experiences have been reported on the use of the 3D                  surgeons in microsurgery. All participants were young
exoscope technology during surgery until recently. In par-                   ENT surgeons but already trained and confident with mi-
ticular, the use of the exoscope has been described for both                 croscopic procedures. Therefore, in our opinion, the simi-
head and neck 9,10,17 and lateral skull base procedures 5,18,19.             larity of results obtained with VITOM® 3D and OM in
The overall degree of precision of manoeuvers, satisfaction                  microvascular training suggests a rapid adaptability in us-
with surgery and ergonomics have been described as ad-                       ing 3D exoscope. In addition, several other studies 5,9,18,19
equate by some authors, and it has been suggested that the                   previously reported other clear advantages obtained with
future trends in surgery will possibly favour the use of 3D                  the use of the 3D exoscopes, such as the quality of image
exoscopes over the OM in certain procedures 19.                              offered, ease of use with reduced muscles fatigue due to
Otolaryngology residents usually perform both microscopic                    the chance to assume a more ergonomic position during
and endoscopic surgery during their training programme.                      surgery and the potential didactic role, based on the pos-
Endoscopic surgery requires the dissociation between man-                    sibility to screen images similarly to the OM. On the other
ual gestures and surgical field that is usually displayed on a               hand, one of the main limitations in the routinely use of 3D
2D screen. It could be inferred that such habit might have fa-               exoscopic systems is the current high cost of these instru-
voured the adaptability of the surgeons involved in the study.               ments, especially compared to the OM. However, recent



                                                                                                                                               227
G. Molteni et al.




studies 24,25 reported that in high volume surgical centres the    manuscript revision. LP and DMa: main intellectual con-
cost of 3D exoscopic system is generally comparable to the         tent, manuscript revision.
cost of OM, considering repair and storage costs and the
continual requirement for sterile covering during surgical         Ethical consideration
procedures.                                                        The study was conducted on ex vivo model; the approval of
Randomised studies, with a large number of participants,           the Institutional Ethics Commitee was not required.
will allow to better demonstrate the effectiveness and ac-         The research was conducted ethically, with all study pro-
tual benefit that the 3D exoscope can provide in microsur-         cedures being performed in accordance with the require-
gical training.                                                    ments of the World Medical Association’s Declaration of
                                                                   Helsinki.
Conclusions                                                        A written consent was obtained from each participant for
                                                                   study participation and data publication.
To the best of our knowledge, this article represents the first
attempt to compare the use of the OM and 3D exoscope
during training for microsurgery. Despite the promising re-        References
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