Efficacy of Videostroboscopy and High-Speed Videoendoscopy to Obtain Functional Outcomes From Perioperative Ratings in Patients With Vocal Fold Mass Lesions

Abstract

Objectives: A major limitation of comparing the efficacy of videostroboscopy (VS) and high-speed videoendoscopy (HSV) is the lack of an objective reference by which to compare the functional assessment ratings of the two techniques. For patients with vocal fold mass lesions, intraoperative measures of lesion size and depth may serve as this objective reference. This study compared the relationships between the pre- to postoperative change in VS and HSV visual-perceptual ratings to intraoperative measures of lesion size and depth.

Design: Prospective visual-perceptual study with intraoperative measures of lesion size and depth.

Methods: VS and HSV samples were obtained preoperatively and postoperatively from 28 patients with vocal fold lesions and from 17 vocally healthy controls. Two experienced clinicians rated amplitude, mucosal wave, vertical phase difference, left-right phase asymmetry, and vocal fold edge on a visual-analog scale using both imaging techniques. The change in perioperative ratings from VS and HSV was compared between groups and correlated to intraoperative measures of lesion size and depth.

Results: HSV was as reliable as VS for ratings of amplitude and edge, and substantially more reliable for ratings of mucosal wave and left-right phase asymmetry. Both VS and HSV had mild-moderate correlations between change in perioperative ratings and intraoperative measures of lesion area. Change in function could be obtained in more patients and for more parameters using HSV than VS. Group differences were noted for postoperative ratings of amplitude and edge; however, these differences were within one level of the visual-perceptual rating scale. The presence of asynchronicity in VS recordings renders vibratory features either uninterpretable or potentially distorted and thus should not be rated.

Conclusions: Amplitude and edge are robust vibratory measures for perioperative functional assessment, regardless of imaging modality. HSV is indicated for evaluation of subepithelial lesions or if asynchronicity is present in the VS image sequence.

Keywords: Assessment; High-speed videoendoscopy; Videostroboscopy; Vocal fold mass lesions; Voice disorders.

Figure 1:

Custom software for dynamically interlinked HSV+DKG playback. The left side displays the full HSV frames, which can be scrolled through consecutively along the time axis; the right side displays the DKG line scan, which can be scrolled through along the posterior-anterior axis. Raters were instructed to select the DKG line scan at the point of maximum amplitude along the anterior-posterior axis to perform ratings.

Figure 2:

A priori established range for agreement: +/− 1/2 scalar level. In Observation 1, the ranges of error do overlap; therefore, these ratings would be considered “in agreement.” In Observation 2, the ranges of error between raters do not overlap; therefore, these ratings would not be considered “in agreement.” Note Rater 2’s lack of confidence is indicated to the right.

Figure 3:

Image capture from the intraoperative recording showing the lesion next to the calibrated right-angle probe. Length (along the anterior-posterior axis) and width (along the medio-lateral axis) were measured using a Cobalt micrometer caliper. Total area for this lesion was calculated based on the standard algebraic equation for an ellipse: $TA\text{=}\frac{\pi {\text{r}}_1{\text{r}}_2}{2}.$

Figure 4:

Scatterplots showing the relationship between lesion size and change in functional ratings for mucosal wave (a,b) and amplitude (c,d) following phonomicrosurgery. Epithelial (a,c) and subepithelial lesions (b,d) are presented separately. Positive numbers on the x-axis indicate an increase in function following surgery, negative numbers indicate a decrease in function following surgery, and vertical lines indicate the effective error of the visual-perceptual scale. Solid symbols represent patients measured using high-speed dynamically interlinked with digital kymography line scans (HSV+DKG) that could not be measured using videostroboscopy (VS).

Figure 5:

Scatterplots showing the relationship between lesion size and change in functional ratings for left-right phase asymmetry (a,b) and vocal fold edge (c,d) following phonomicrosurgery. Epithelial (a,c) and subepithelial lesions (b,d) are presented separately. Negative numbers on the x-axis indicate an improvement in function following surgery, positive numbers indicate a decline in function following surgery, and vertical lines indicate the effective error of the visual-perceptual scale. Solid symbols represent patients measured using high-speed dynamically interlinked with digital kymography line scans (HSV+DKG) that could not be measured using videostroboscopy (VS).