Page 317 - Control Theory in Biomedical Engineering

Continuum NasoXplorer manipulator with shape memory actuators 291

significant force will be required to actuate the longer tip. Hence, we studied
various randomized trials and reviewed the anthropometric measurements.

2.1.3 Anatomical variations based on age and gender
In a 2013 study, among 69 healthy volunteers, it was observed that males
tend to have larger nostrils than females (Schriever et al., 2013). Males
2
had an average nostril opening cross-sectional area of 407mm , whereas
2
females had an average cross-sectional area of 310mm . This suggests a
diameter of 10–11mm. This study did not consider different age groups.
However, it is good to note that the average age of all 69 subjects is 35 years
old. In another study done in 2005, boys had an average nostril opening
2
cross-sectional area of 72.3mm , while girls had an average nostril opening
2 2
cross-sectional area of 66.0mm , suggesting a diameter to 5mm , which is
half that of an adult (Mori et al., 2005).

2.1.4 Estimation of the distance between nasal inlet to the channel
The distance from the nasal inlet to the nasopharynx region can extend up to
14cm (Taylor et al., 2019). Although the NasoXplorer is 22.7cm long, only
8.5cm was intended for use within the human body. Other parts of the
NasoXplorer are not intended to be inside the human body. However, these
are average measurements for Caucasian males only, and it should be noted
that Asians may have a smaller distance between nasal inlet and channel.
Since our target audience is Asians, the NasoXplorer is sufficient for viewing
most of the nasopharynx region.

2.1.5 Estimation of area of narrowest path in the nasopharynx region
One cross-sectional study examined the differences in nasopharyngeal area
in 96 individuals aged 6–59 years old without facial abnormalities
(De Arau ´jo et al., 2016). Subjects were split into four age groups, but no
differences were found in their nasopharyngeal cross-sectional areas, and
2
all were slightly more prominent than 1cm . Since the segment of the
NasoXplorer entering the nose has a diameter of a maximum of 4mm,
we have met the requirements that we set out to achieve.

2.1.6 Device design specifications
Following the preceding findings, our own design specifications aim to cater
to people of various anatomical differences.