Key-words:
Craniotomy - evacuation - exoscope - intracranial hemorrhage - ORBEYE
Introduction
Young neurosurgeons have frequently encountered difficulty gaining sufficient opportunities
to acquire skills in microneurosurgery because of recent advances in internal medicine,
endovascular therapy, and endoscopic surgery for cerebrovascular disease.[[1]],[[2]],[[3]] Surgery for intracranial hemorrhage (ICH) has been reported as the basis of microneurosurgery
and can provide an educational resource.[[4]] In microsurgeries using ORBEYE, the posture of the assistant is comfortable enough
to assist in the surgery.[[5]],[[6]],[[7]],[[8]],[[9]],[[10]] This can increase the opportunities in microsurgical education for the trainee.
We evaluated a 4-hands surgery for ICH using ORBEYE to validate the educational value
and ergonomic advantage of this method.
Methods
Ethics approval for the study was obtained from our institutional review board (approval
number 191205). Evacuation of ICH was performed with the patient's informed consent.
The surgical inclusion criteria were ICH confirmed on brain computed tomography with
hemorrhage volume >20 ml on admission and cases within 48 h of onset. Patient background
and results of treatment were investigated. Thirty consecutive patients who underwent
ICH evacuation using ORBEYE between December 2018 and May 2020 were investigated retrospectively.
All operations were performed by a team comprising a supervisor (as an assistant)
and a trainee (as the main operator). ORBEYE, a high-resolution (4K), 3-dimensional
(3D) exoscope, was set and used during intradural manipulation. The assistant set
the visual axis of the exoscope, and adjusted focus and magnification as a scopist.
After setting the ORBEYE, the assistant (supervisor) helped retract the brain and
withdraw and irrigate the hematoma using suction tubes or brain retractors. Moreover,
the operator (the trainee) evacuated the hematoma with a suction tube and coagulated
using bipolar forceps. The postures of the main operator and the assistant when the
visual axis of the ORBEYE were set in the 0, 3, 6, and 9 o'clock directions during
hematoma evacuation were observed, and schemas were developed and compared with the
use of a conventional surgical microscope.
Results
In all 30 cases, all microsurgical procedures were performed using only ORBEYE. The
patient background characteristics and results of treatment are shown in [[Table 1]].
Table 1: Patient’s characteristics
All microsurgical procedures by the trainee were accomplished with the supervisor
using ORBEYE. Educational assistance and oversight by the supervisor were provided
in all cases [[Figure 1]]. Because the supervisor's hands could move freely in the surgical field, the trainee
and the supervisor could perform 4-hand microsurgery cooperatively in all the cases
[[Figure 2]]. During microsurgical manipulation in all directions (0, 3, 6, and 9 o'clock directions)
of the hematoma, the operator and the assistant bent their elbow joints moderately,
facing the monitor, and could perform a stable operation in a comfortable posture
[[Figure 3]].
Figure 1: The whole operative view for the hematoma evacuation using ORBEYE. The operator (the
trainee, right side) and the assistant (the supervisor, left side) bend their elbow
joints moderately, facing the monitor, and they can perform a stable operation in
a comfortable posture. The assistant (the supervisor) helps retract the brain using
brain retractors and sets the visual axis of ORBEYE and adjusts focus and magnification
as a scopist
Figure 2: The whole operative view of 4-hands surgery for the hematoma evacuation using ORBEYE.
The operator (the trainee, right side) and the assistant (the supervisor, left side)
bend their elbow joints moderately, facing the monitor, and they can perform a stable
operation in a comfortable posture. The operator (the trainee) evacuated the hematoma
with a suction tube and coagulated using bipolar forceps. The assistant (the supervisor)
helps retract the brain using brain retractors and withdraw and irrigate the hematoma
using suction tubes or brain retractors
Figure 3: Comparison between the ORBEYE and the conventional microscope. In the 12 o’clock
direction: (a) Using the ORBEYE, the operator bends the elbow moderately. (b) Using
the microscope, the operator stretches the elbow excessively. In the 6 o’clock direction:
(c) Using the ORBEYE, the operator bends the elbow moderately. (d) Using the microscope,
the operator bends the elbow excessively. In the 9 o’clock direction: (e) Using the
ORBEYE, the assistant bends the elbow moderately. (f) Using the microscope, the assistant
scope can sometimes hinder the angle of the microscope
Discussion
Recently, introduction of the exoscope into the neurosurgery has been expected to
have ergonomic and educational merits.[[5]],[[6]],[[7]],[[8]],[[9]],[[10]],[[11]],[[12]],[[13]],[[14]],[[15]],[[16]] No case series of ICH evacuation using an exoscope have been reported. In the present
case series, mean intraoperative blood loss, rate of rebleeding, rate of complications
related to the operation, and the mortality rate were 38.5 ± 57.9 ml, 0%, 6.6%, and
6.6%, respectively, whereas in previous reports, they were 53.7–605.6 ml,[[17]],[[18]] 8%–18%,[[18]],[[19]] 8%–58.9%,[[20]],[[21]] and 9%–25%,[[17]],[[19]],[[20]],[[21]] respectively. Thus, the results of the present case series were not inferior to
previous reports.[[17]],[[18]],[[19]],[[20]],[[21]]
In the general endoscopic surgery, a scopist is expected to have enough knowledge
and experience to ensure the operative field.[[22]] In the neurosurgery, we are also expected to have those, in performing the microsurgery
using the exoscope. To improve efficiency of operative education, in our institution,
we established the policy that a supervisor ensured the operative field and set the
visual axis as a scopist, including manipulation of exoscope, and a trainee dedicated
operative procedure for ICH evacuation. Schemas showing that a trainee (main operator)
and a supervisor (assistant) can cooperatively perform 4-hand microsurgery in a comfortable
posture have been developed [[Figure 2]]. Using ORBEYE, a trainee and a supervisor bend the elbow joint more comfortably
during microsurgical manipulation in all directions (12, 3, 6, and 9 o'clock directions)
of the hematoma, compared to using a conventional microscope [[Figure 3]]. Thus, the supervisor can help the trainee every step of the way. Furthermore,
the sharing of the 3D operative field using ORBEYE is also useful as an educational
tool.[[14]] In the present series, the trainee and supervisor could share the 3D operative
field with comfortable postures. Therefore, ORBEYE appears to have excellent educational
value.
Conclusion
Exoscopic 4-hands evacuation of ICH is feasible and safe and provides excellent educational
value and ergonomic advantages, increasing the opportunities for education in microsurgery.
