IEEE Robotics & Automation Magazine - March 2022 - 72

SUS Scores
100
80
60
40
20
93.75 100
65
87.5 92.5
81.35
95
68.75 76.25 76.25 76.25
Users
Figure 6. The SUS scores of lay users (blue) and surgeons (red) for surgical task B.1.
comparisons are statistically significant according to the Wilcoxon
sign test, considering the results nonnormally distributed
with p < 0.05. The 3 F grasper required slower movements to
perform the same task when compared to the DV grasper.
Moreover, the UEF demonstrated that the users had a preference
for the DV tool for this type of pick-and-place task and
that the 3 F grasper was deemed unnecessarily complex.
Questionnaires
The SUS results taken after the trials showed a median score
of 78.8 and 79.4 for the lay users and experienced surgeons,
respectively, demonstrating a similar ease of use of the two
graspers (Figure 6). The NASA-TLX questionnaire (Figure
7) recorded median values of 19.8 and 27.3 for the lay
80
70
60
50
40
30
20
10
66.25
participants using DV and 3 F, respectively,
while for the surgeons, the
median values were 10.6 and 22.3,
indicating their ease of use of the DV
grasper and a higher effort in using
the more articulated grasper. Both
sets of results have shown a statistically
significant difference, with p <0.05
demonstrating the DV grasper's
advantage for performing pick-andplace
tasks.
Articulated Shaft Comparison
Performance
As before, the mean time and velocity among participants
were compared using the two surgical tools. Both the duration
of the task and speed of performance showed almost the
same values between the two articulated instruments: the
mean transfer time was 3.98 ± 1.12 s and 3.63 ± 1.15 s for the
shaft with a W and the shaft with an additional E, respectively.
The mean transfer velocity was 11.24 ± 3.4 cm/s for the W
and 11.08 ± 3.49 cm/s for the E. The surgeons involved in the
trials performed similarly, with a mean transfer time of 2.59 s
and mean velocity of 16.69 cm/s (Figure 8). According to the
Wilcoxon test, the performance differences between the two
shafts are not statistically relevant.
DV 3F
NASA-TLX
Figure 7. The NASA-TLX average scores for surgical task B.1.
7
6
5
4
3
2
1
Duration (s)
(a)
Wrist
Elbow
Figure 8. (a) The mean transfer duration and (b) velocity for
surgical task B.2.
72 * IEEE ROBOTICS & AUTOMATION MAGAZINE * MARCH 2022
0.18
0.16
0.14
0.12
0.1
0.08
0.06
0.4
0.02
Velocity (cm/s)
(b)
Questionnaires
The SUS results showed a median value of 70 and 35 for the lay
users and surgeon, respectively, (Figure 9). The lower usability
scores recorded for the first experiment were likely due to the
more extensive wearable kit required for control of the shaft but
also because of the higher complexity of the articulated shaft's
control. The NASA-TLX results demonstrated median values
of 54.67 and 57 for the W and the E, respectively, for lay users,
and 18.7 and 60.3, for the W and the E, respectively, as perceived
by the surgeon (Figure 10). A lower workload was
reported when using the shaft with only a W. As stated in the
UEF, participants found moving the wrist to control the tool
orientation relatively easy, but a few of them found it difficult to
reach certain targets in a comfortable orientation when controlling
the shaft with the E. In general, seven subjects out of 10,
including the surgeon, preferred the W shaft configuration,
finding the shaft with an elbow configuration unnecessary
complex and harder to control for this type of task.
SUS Scores
100
50
35
60 70 67.5 87.5 77.5
Users
Figure 9. The SUS scores of lay users (blue) and surgeons (red)
for surgical task B.2.
92.5
60
70 70
Score
Score
Score
IEEE Robotics & Automation Magazine - March 2022

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