Ergonomic advantage of pistol-grip endoscope in the ENT practice

Abstract

Objectives: Recent technology manufactured a nasopharyngeal videoscope with pistol-shaped grip (PG). This study aimed to assess the ergonomic feasibility of this novel device in daily ENT practice.

Methods: To assess the ergonomic impact of grip shape on ENT physicians, conventional grip videoscope (CG) and PG were utilized in this study. Surface electromyography (sEMG) was recorded to assess the muscle activity in the upper limb during endoscopy on a training model. Bilateral sEMG recordings were performed including thenar muscle, pronator teres muscle, brachioradialis muscle, and biceps brachii muscle. Mean value of the mean sEMG amplitude throughout the task in triplicated examinations (mMA) with each electrode, total values of four mMAs in both of the grip-side and the insertion tube-side limb muscles, and total value of all eight mMAs were calculated, and compared between CG and PG. Subgroup analyses were also performed in the experienced ENT physicians and the residents.

Results: PG provided significantly lower mMA values in thenar muscle and brachioradialis muscle of the grip-side limb compared with CG. Total value of four mMAs in PG was significantly lower compared with that in CG in the grip-side limb, and total value of all eight mMAs in PG was significantly lower compared with that in CG. Furthermore, total value of four mMAs in PG was significantly lower compared with that in CG in the grip-side limb, in both of the subgroups.

Conclusion: This is the first study to support the idea that the newly designed pistol-grip endoscope may have an ergonomic advantage over conventional endoscope for otolaryngologists in daily practice.

Level of evidence: 4.

Keywords: ENT practice; electromyography; ergonomics; nasopharyngeal endoscopy.

FIGURE 1

Flexible ENT endoscopes incorporated in this study. Conventional grip videoscope (A, ENF‐VH; OLYMPUS), and recently manufactured pistol‐shaped grip videoscope (B, ENF‐VH2; OLYMPUS) were used in this study

FIGURE 2

Placements of surface EMG electrodes. Electrodes were placed on bilateral TM, PT, BR, and BB. Sixteen participants manipulated the grip in their left hands as shown in this figure, and residual two participants manipulated the grip in their right hands. BR, brachioradialis muscle; BB, biceps brachii muscle; TM, thenar muscle; PT, pronator teres muscle

FIGURE 3

Manipulation of the videoscope by the up/down angulation control lever. Images of the grip‐side hand holding the CG (A–C) and PG (D–F) are shown. The control lever is regulated by thenar muscle (TM) to flex the metacarpophalangeal (MP) joint (arrow) and the caropometacarpal (CM) joint (arrowhead) of the thumb. Pictures at the neutral position (A, D), and at the up (B, E)/down (C, F) angulation control positions are shown. CG, conventional grip videoscope; PG, pistol‐shaped grip videoscope

FIGURE 4

Surface EMG recording during the NPE tasks. Simultaneous recording of sEMG in the targeted eight muscles of the participant was performed during NPE tasks performed on a training model set on a treatment chair. NPE, flexible nasopharyngeal endoscopy; sEMG, surface EMG

FIGURE 5

A series of tasks utilized in this study. Endoscopic tasks consisted of the following 12 steps. (1) insert the tip through the nose; (2) hold the distant laryngeal view, A; (3) hold the close laryngeal view, B; (4) hold the left hypopharyngeal view, C; (5) manipulate the tip of the endoscope upward, D; (6) manipulate the tip of the endoscope downward, E; (7) touch the mark in the left pyriform fossa by the tip of the endoscope, F; (8‐11) repeat steps 4‐7 in the right hypopharynx; and (12) remove the endoscope. Each view was held for 5 seconds

FIGURE 6

The elbow flexion angle during NPE. Three landmarks were set on the still images of one participant during NPE at the task to hold the distal laryngeal view. The landmarks were (a) the acromion (black arrowhead), (b) the humerus lateral epicondyle (white arrowhead), and (c) the middle point between the radial styloid process and the ulnar head (arrow). ¹⁸ Lines to connect a‐b, and b‐c were drawn, and the angles between these lines were measured to assess the elbow flexion angle in CG and that in PG. CG, conventional grip videoscope; NPE, flexible nasopharyngeal endoscopy; PG, pistol‐shaped grip videoscope