Page 334 - Flexible Robotics in Medicine

324 Chapter 13
Table 13.14: DFMEA and mitigations.

Failure mode Cause of failure Harm Risk Mitigation
Improper Failure to align the Discomfort High A direction of the insertion
insertion/removal device with a nasal tube is guided via a gear
of the orifice rack alignment unit of frame
nasopharyngeal
endoscope tube
“Overbending” of Failure of a delicate Discomfort Moderate Mitigated with a joystick
a nasopharyngeal motor control control that allows for
endoscope tip mechanism precise maneuvers
“Underbending” Structural design Failure to fully observe Low Mitigated with a joystick
of a flaw or failure of a the nasopharyngeal control that allows for
nasopharyngeal delicate motor cavity using a device precise maneuvers
endoscope tip control mechanism
Allergic reaction Non- Allergy or possibly Low Perform appropriate
biocompatibility of death (depending) on biocompatibility testing in
the device material the severity of reaction future as per ASTM
standards with an
appropriate chosen
biocompatible material
(UHMWPE)
Breakage of Mechanical failure Possible choking Moderate As per design verification
cables of the material hazard and discomfort (Section 13.6), a likelihood
of failure is exceptionally
slim
Loosening of Structural design Possible difficulty in Moderate As per design verification
nasopharyngeal flaw or failure extracting device from (Section 13.6), a likelihood
endoscope the nasopharyngeal of failure is exceptionally
segments cavity and discomfort slim

13.7.3 Design failure mode and effect analysis

In addition to fulfilling the design acceptance criteria, the device must also be successfully
verified in terms of design failure mode and effect analysis (DFMEA). Table 13.14
illustrates the possible risks involved in the use of BEE and how we mitigate these risks by
means of design considerations.

13.8 Conclusion

In conclusion, BEE is a device that presents a solution to the problem of NPC surveillance.
BEE has a comparable field of view as measured against three other available flexible
endoscopes. BEE is a new, home-based, intuitive endoscope system to survey their
nasopharyngeal cavity. The current working mode of BEE is partially automated. It requires
users to make use of the joystick control interface to manipulate the endoscope.