Impact of resection depth on voice outcomes following transoral laser microsurgery for early glottic lesions

	Laser cordectomy Type I; n = 13	Laser cordectomy Type II/III; n = 16
Male, n (%)	11 (84.6)	15 (93.8)
Age at cordectomy, years, mean (SD)	66.9 (5.3)	68.0 (7.8)
Smoking before treatment, n (%)	10 (76.9)	11 (68.8)
Brinkman index, mean (SD)	794.6 (700.9)	593.8 (692.6)
Brinkman index, n (%)
Light (0–199)	4 (30.8)	5 (31.3)
Moderate (200–599)	1 (7.7)	4 (25.0)
Heavy (≥ 600)	8 (61.5)	7 (43.8)
GERD symptoms, n (%)	6 (46.2)	4 (25.0)
Allergy, n (%)	2 (15.4)	2 (12.5)
Thyroid disease, n (%)	1 (7.7)	1 (6.3)
Neck spine issues, n (%)	6 (46.2)	3 (18.8)
Loud speech, n (%)	7 (53.8)	9 (56.3)
Fast speech tempo, n (%)	4 (30.8)	4 (25.0)
Vocal strain, n (%)
Mild	7 (53.8)	7 (43.8)
Moderate	4 (30.8)	4 (25.0)
Severe	2 (15.4)	5 (31.3)
Hearing, n (%)
Good	12 (92.3)	15 (93.8)
Poor	0 (0)	1 (6.3)
Hearing aid	1 (7.7)	0 (0)

[i] GERD = gastroesophageal reflux disease; SD = standard deviation

TABLE 4.

Objective assessments of vocal fold function and voice quality; by study group and time of measurement

Parameter / Patient group	Before treatment	1 month after treatment	3 months after treatment	12 months after treatment	P-value ¹
Fundamental laryngeal frequency (F0), Hz
Cordectomy Type I	156.19 ± 11.40 (147)	170.49 ± 12.95 (154)	166.58 ± 11.55 (165)	164.27 ± 10.26 (150)	0.562
Cordectomy Type II/III	147.92 ± 10.29 (131)	182.76 ± 16.12 (162)	161.26 ± 10.56 (149)	168.67 ± 11.61 (155)	0.153
P-value ²	0.595	0.571	0.737	0.784	0.652
Jitter, %
Cordectomy Type I	2.18 ± 0.60 (1.5)	2.10 ± 0.51 (1.7)	2.22 ± 0.52 (1.4)	2.19 ± 0.44 (1.6)	0.996
Cordectomy Type II/III	3.73 ± 1.13 (1.8)	5.04 ± 0.82 (4.2)	3.84 ± 0.78 (2.9)	4.06 ± 0.84 (3.1)	0.519
P-value ²	0.268	0.008	0.111	0.075	0.606
Shimmer, %
Cordectomy Type I	5.83 ± 1.29 (3.9)	5.87 ± 0.90 (4.3)	5.66 ± 0.87 (4.3)	6.17 ± 0.89 (6.0)	0.975
Cordectomy Type II/III	8.53 ± 1.45 (6.4)	12.76 ± 1.67 (11.0)	7.68 ± 1.04 (7.7)	9.06 ± 1.07 (7.9)	0.010
P-value ²	0.185	0.001	0.158	0.053	0.057
Noise-to-harmonic ratio (NHR)
Cordectomy Type I	0.17 ± 0.02 (0.13)	0.16 ± 0.02 (0.15)	0.15 ± 0.02 (0.14)	0.16 ± 0.02 (0.14)	0.837
Cordectomy Type II/III	0.24 ± 0.05 (0.16)	0.36 ± 0.06 (0.30)	0.21 ± 0.04 (0.17)	0.26 ± 0.04 (0.20)	0.064
P-value ²	0.192	0.004	0.202	0.070	0.133
Soft phonation index (SPI)
Cordectomy Type I	17.38 ± 2.46 (15.8)	16.90 ± 3.04 (13.6)	18.05 ± 1.70 (17.4)	13.71 ± 2.14 (10.2)	0.482
Cordectomy Type II/III	18.65 ± 2.76 (17.8)	12.20 ± 2.02 (10.8)	21.40 ± 3.17 (18.1)	14.59 ± 1.81 (13.6)	0.005
P-value ²	0.739	0.195	0.363	0.754	0.221
Voice turbulence index (VTI)
Cordectomy Type I	0.06 ± 0.02 (0.05)	0.06 ± 0.01 (0.04)	0.05 ± 0.01 (0.04)	0.06 ± 0.01 (0.06)	0.693
Cordectomy Type II/III	0.08 ± 0.01 (0.06)	0.14 ± 0.02 (0.11)	0.10 ± 0.03 (0.06)	0.11 ± 0.03 (0.07)	0.099
P-value ²	0.500	0.010	0.089	0.099	0.196
Maximum phonation time (MPT), seconds
Cordectomy Type I	13.9 ± 0.9 (14)	14.9 ± 1.5 (13.0)	16.3 ± 1.9 (14.0)	16.2 ± 1.1 (15.0)	0.341
Cordectomy Type II/III	13.9 ± 1.2 (13.5)	9.8 ± 1.0 (9.5)	8.5 ± 0.8 (8.0)	12.9 ± 1.4 (13.0)	0.002
P-value ²	0.955	0.006	0.002	0.100	0.001
Mean loudness (ML), dB
Cordectomy Type I	57.40 ± 1.49 (56.4)	58.33 ± 1.84 (58.2)	60.46 ± 1.38 (58.4)	57.07 ± 1.59 (58.0)	0.191
Cordectomy Type II/III	54.76 ± 1.70 (55.1)	55.48 ± 3.14 (53.9)	59.05 ± 1.49 (58.2)	60.05 ± 1.39 (60.6)	0.087
P-value ²	0.263	0.467	0.501	0.168	0.206
S/Z Ratio
Cordectomy Type I	1.04 ± 0.06 (1.0)	1.01 ± 0.02 (1.0)	0.93 ± 0.04 (1.0)	0.94 ± 0.05 (1.0)	0.240
Cordectomy Type II/III	1.04 ± 0.04 (1.0)	1.58 ± 0.24 (1.3)	1.26 ± 0.13 (1.0)	1.20 ± 0.11 (1.0)	0.048
P-value ²	0.981	0.029	0.026	0.037	0.071
Reflux symptom index (RSI)
Cordectomy Type I	10.5 ± 2.3 (8.0)	7.8 ± 1.5 (8.0)	7.9 ± 1.4 (9.0)	7.9 ± 1.7 (6.0)	0.324
Cordectomy Type II/III	10.3 ± 1.9 (8.0)	10.9 ± 1.8 (9.0)	8.6 ± 1.6 (7.5)	7.3 ± 1.4 (5.5)	0.045
P-value ²	0.923	0.202	0.774	0.782	0.278
Reflux finding score (RFS)
Cordectomy Type I	7.1 ± 1.5 (5.0)	6.5 ± 1.3 (5.0)	6.5 ± 1.1 (5.0)	4.2 ± 1.0 (4.0)	0.014
Cordectomy Type II/III	5.5 ± 1.2 (7.0)	6.2 ± 1.4 (6.5)	6.5 ± 1.3 (6.0)	5.6 ± 0.9 (5.5)	0.664
P-value ²	0.412	0.854	0.982	0.343	0.184
Muscle tension dysphonia (MTD), n (%)
Cordectomy Type I	2/13 (15.4)	3/13 (23.1)	3/13 (23.1)	2/13 (15.4)	1
Cordectomy Type II/III	3/16 (18.8)	7/16 (43.8)	7/16 (43.8)	8/16 (50.0)	0.068
P-value ²	0.981	0.029	0.026	0.037	0.071
Reflux symptom index (RSI)
Cordectomy Type I	10.5 ± 2.3 (8.0)	7.8 ± 1.5 (8.0)	7.9 ± 1.4 (9.0)	7.9 ± 1.7 (6.0)	0.324
Cordectomy Type II/III	10.3 ± 1.9 (8.0)	10.9 ± 1.8 (9.0)	8.6 ± 1.6 (7.5)	7.3 ± 1.4 (5.5)	0.045
P-value ²	0.923	0.202	0.774	0.782	0.278
Reflux finding score (RFS)
Cordectomy Type I	7.1 ± 1.5 (5.0)	6.5 ± 1.3 (5.0)	6.5 ± 1.1 (5.0)	4.2 ± 1.0 (4.0)	0.014
Cordectomy Type II/III	5.5 ± 1.2 (7.0)	6.2 ± 1.4 (6.5)	6.5 ± 1.3 (6.0)	5.6 ± 0.9 (5.5)	0.664
P-value ²	0.412	0.854	0.982	0.343	0.184
Muscle tension dysphonia (MTD), n (%)
Cordectomy Type I	2/13 (15.4)	3/13 (23.1)	3/13 (23.1)	2/13 (15.4)	1
Cordectomy Type II/III	3/16 (18.8)	7/16 (43.8)	7/16 (43.8)	8/16 (50.0)	0.068
P-value ²	1	0.433	0.433	0.114	-
Intensity of scarring, n (%)
Cordectomy Type I					0.667
Mild	-	11 (84.6)	10 (76.9)	12 (92.3)
Moderate	-	2 (15.4)	3 (23.1)	1 (7.7)
Severe	-	0 (0)	0 (0)	0 (0)
Cordectomy Type II/III					1
Mild	-	10 (62.5)	11 (68.8)	11 (68.8)
Moderate	-	4 (25.0)	4 (25.0)	4 (25.0)
Severe	-	2 (12.5)	1 (6.3)	1 (6.3)
P-value ²	-	0.477	1	0.343	-

1 Comparison between measurement within patient group;

2 Comparison between patient groups within measurement;

3 Interaction between main factors (patient group, measurement)

Unless otherwise specified, the data are presented as mean ± standard error (median).

TABLE 3.

Videostroboscopic assessments of vocal fold function; by study group and time of measurement

Parameter / Patient group	Before treatment	1 month after treatment	3 months after treatment	12 months after treatment	P-value¹
Vocal fold vibratory amplitude
Cordectomy Type I					0.002
Appropriate	0 (0)	1 (7.7)	3 (23.1)	5 (38.5)
Diminished	8 (61.5)	6 (46.2)	7 (53.8)	6 (46.2)
Absent	5 (38.5)	6 (46.2)	3 (23.1)	2 (15.4)
Cordectomy Type II/III					0.002
Appropriate	1 (6.3)	0 (0)	0 (0)	0 (0)
Diminished	2 (12.5)	2 (12.5)	7 (43.8)	10 (62.5)
Absent	13 (81.3)	14 (87.5)	9 (56.3)	6 (37.5)
P-value ²	0.016	0.041	0.049	0.022	-
Vocal fold phase symmetry
Cordectomy Type I					0.024
Symmetrical	0 (0)	0 (0)	2 (15.4)	4 (30.8)
Asymmetrical	13 (100)	13 (100)	11 (84.6)	9 (69.2)
Cordectomy Type II/III					0.572
Symmetrical	1 (6.3)	0 (0)	0 (0)	1 (6.3)
Asymmetrical	15 (93.8)	16 (100)	16 (100)	15 (93.8)
P-value ²	1	-	0.192	0.144	-
Vocal fold vibration regularity
Cordectomy Type I					0.024
Regular	0 (0)	0 (0)	2 (15.4)	4 (30.8)
Irregular	13 (100)	13 (100)	11 (84.6)	9 (69.2)
Cordectomy Type II/III					0.572
Regular	1 (6.3)	0 (0)	0 (0)	1 (6.3)
Irregular	15 (93.8)	16 (100)	16 (100)	15 (93.8)
P-value ²	1	-	0.192	0.144	-
Vocal fold closure
Cordectomy Type I					0.003
Complete	2 (15.4)	2 (15.4)	4 (30.8)	5 (38.5)
Brief	5 (38.5)	5 (38.5)	8 (61.5)	7 (53.8)
Absent	6 (46.2)	6 (46.2)	1 (7.7)	1 (7.7)
Cordectomy Type II/III					0.338
Complete	2 (12.5)	2 (12.5)	2 (12.5)	3 (18.8)
Brief	6 (37.5)	3 (18.8)	8 (50.0)	8 (50.0)
Absent	8 (50.0)	11 (68.8)	6 (37.5)	5 (31.3)
P-value ²	1	0.450	0.145	0.259	-
Mucosal wave movement
Cordectomy Type I					0.001
Normal	0 (0)	0 (0)	3 (23.1)	5 (38.5)
Disturbed	8 (61.5)	7 (53.8)	7 (53.8)	6 (46.2)
Absent	5 (38.5)	6 (46.2)	3 (23.1)	2 (15.4)
Cordectomy Type II/III					0.001
Normal	0 (0)	0 (0)	0 (0)	1 (6.3)
Disturbed	4 (25.0)	3 (18.8)	9 (56.3)	10 (62.5)
Absent	12 (75.0)	13 (81.3)	7 (43.8)	5 (31.3)
P-value ²	0.067	0.064	0.125	0.126	-

1 Comparison between measurement within patient group;

2 Comparison between patient groups within measurement;

3 Interaction between main factors (patient group, measurement)

Data are frequencies (%).

TABLE 2.

Patient assessment of voice quality and satisfaction; by study group and time of measurement

Parameter / Patient group	Before treatment	1 month after treatment	3 months after treatment	12 months after treatment	P-value ¹
Voice quality (VAS)
Cordectomy Type I	4.8 (0.5)	3.9 (0.5)	3.5 (0.5)	3.0 (0.4)	0.040
Cordectomy Type II/III	5.6 (0.3)	5.7 (0.6)	4.3 (0.6)	3.6 (0.5)	0.031
P-value ²	0.342	0.032	0.279	0.367	P-value³ = 0.635
Voice handicap index score (VHI)
Cordectomy Type I	26.9 (7.9)	19.5 (4.9)	15.7 (5.2)	9.2 (3.6)	0.041
Cordectomy Type II/III	31.6 (6.0)	41.0 (6.8)	24.4 (6.3)	26.6 (7.5)	0.016
P-value ²	0.404	0.039	0.210	0.195	P-value³ = 0.263

1 Comparison between measurement within patient group;

2 Comparison between patient groups within measurement;

3 Interaction between main factors (patient group, measurement); VAS = visual analog scale; VHI = voice handicap index

Data are mean values (standard errors)

Visual Analogue Scale (VAS) evolution during follow-up.

Voice Handicap Index (VHI) evolution during follow-up.

TABLE 5.

Exploratory comparison between classical full-length type I cordectomy and limited mucosal resections within Group 1

Variable	Full-length Type I Cordectomy	Mean of Type I Cordectomy With Partial Mucosal Preservation Group	SD	z-score
Mean loudness (ML) preoperative (dB)	46.42	58.32	4.42	−2.69
Fundamental laryngeal frequency (F0) 1 month postoperatively (Hz)	266.45	162.49	38.34	+2.71
Jitter, 1 month postoperatively (%)	6.877	1.700	1.211	+4.28
Mean loudness (ML) 1 month postoperatively (dB)	43.42	59.57	5.12	−3.15
Noise-to-harmonic ratio (NHR) 1 month postoperatively	0.300	0.152	0.041	+3.61
Fundamental laryngeal frequency (F0) 3 months postoperatively (Hz)	276.17	157.45	26.65	+4.46
Jitter, 3 months postoperatively (%)	5.675	1.935	1.612	+2.32
Voice turbulence index (VTI) 3 months postoperatively	0.123	0.045	0.018	+4.38
Fundamental laryngeal frequency (F0) 12 months postoperatively (Hz)	254.02	156.79	26.45	+3.68
Jitter, 12 months postoperatively (%)	5.457	1.913	1.300	+2.73
Shimmer, 12 months postoperatively (%)	14.651	5.465	2.008	+4.57
Noise-to-harmonic ratio (NHR) 12 months postoperatively	0.341	0.146	0.036	+5.36

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DOI: https://doi.org/10.2478/raon-2026-0052 | Journal eISSN: 1581-3207 | Journal ISSN: 1318-2099

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Language: English

Submitted on: Apr 30, 2026

Accepted on: May 29, 2026

Published on: Oct 22, 2026

Published by: Association of Radiology and Oncology

In partnership with: Paradigm Publishing Services

Publication frequency: 4 issues per year

Keywords:

larynx,

CO₂ laser,

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© 2026 Miha Zabret, Marc Remacle, Maja Sereg Bahar, Ales Groselj, published by Association of Radiology and Oncology
This work is licensed under the Creative Commons Attribution 4.0 License.

AHEAD OF PRINT

Impact of resection depth on voice outcomes following transoral laser microsurgery for early glottic lesions

Figures & Tables

FIGURE 1.

TABLE 1.

TABLE 4.

TABLE 3.

TABLE 2.

FIGURE 2.

FIGURE 3.

TABLE 5.

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