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OmniFlex: omnidirectional flexible hand-held endoscopic manipulator with spheroidal joint 475

because of how it is structured. It is inconvenient for the operator to examine a tumor at a
different angle when rotating the whole endoscopic instrument.

Studies have shown that the number of cases of NPC has increased from 45,000 deaths in
1990 to 65,000 deaths in 2010, which is a shocking 20,000 increase in the number of death
cases in 20 years, and this is a key for concern [15]. Besides, the demand for endoscopic
manipulators has increased due to the increased demand for detection and minimally
invasive procedure [15]. In terms of potential applications, otolaryngologists often perform
a NE locally, and during abnormality in the airway, especially in the nasopharyngeal area, a
biopsy is needed to obtain the lesion for further tests.

21.1.3 Endoscopic manipulators

There are different types of endoscopic manipulators with different designs and dimensions
to cater to different diagnoses and surgical needs. For example, the use of colonoscopies for
the imaging of the entire length of the colon and large intestine, and endoscopic
manipulators for the early detection of NPC.
For places that are harder to reach or requires up and down movement, the operator would
have to tilt or rotate the whole endoscopic prototype, which makes the manipulation of the
endoscopic manipulator to be associated with awkward body postures. This manipulation is
inconvenient and may require more than a single person to operate, and this may not be
very ideal. Moreover, musculoskeletal complaints are widespread and higher for operators
handling endoscopic manipulators as compared to other medical specialists [16]. Lastly, the
forceps at the distal end of the endoscopic manipulator usually has straight and passive
configurations. For the places in the nasal cavity that are difficult to reach, such as tumor
growing under the lining of the nasopharynx in the tissue layer called submucosa, steerable
and controllable forceps can reach the correct angle to the desired location. It is difficult to
operate the prototype intuitively, as it requires extreme rotation and extension of the wrist
and finger.
The insertion of the nasal endoscopic manipulator into the nasal passage of the patient is
very uncomfortable to introduce a prototype into the nasal cavity of the patient with a
diameter slightly smaller than the nostrils. The larger diameters of the nasopharyngeal
endoscopic manipulator can be up to 5 6 mm. Therefore the application of local anesthesia
and nasal decongestant for reduced swelling is of critical importance [17]. Some flexible
endoscopic manipulators have large diameters that cause discomfort to patients upon
insertion into the nasal cavity. Smaller endoscopic manipulators often have limited
instrument channels and dexterity.

One other problem is the low maneuverability of existing flexible endoscopic manipulators,
which have distal ends that actively curve according to the operator’s manipulation. The