2018 Section 6 - Laryngology, Voice Disorders, and Bronchoesophalogy

S.-K.

Baek et

al.

/ Auris

Nasus

Larynx

44

(2017)

583 – 589

minimal

neural

damage,

such

as

traction

or

thermal

damage

careful

capsular dissection was performed

identified. However,

lead

to

these

voice

changes. Even

if

some

damage may

be

prevent

injury

to

the

EBSLNs

on

the

superior

pole

of

the

may

to

the

use

of

IONM

can

reduce

the

minor

neural

In particular,

the branches of

superior

thyroid artery were

inevitable,

gland.

and

ligated

separately.

damage.

identified

the

objective

of

this

study

is

to

identify

any

integrity

monitor

(NIM)

electromyogram system, Medtronic Florida, USA) was

(EMG) Xomed

Nerve

Therefore,

difference

tracheal Surgical laryngeal

of

voice

outcome

according

to

the and

use

of

IONM

tube

(NIM-Response

2.0

thyroid

surgery

by

performing

pre-

post-operative

Products,

Jacksonville,

used

for

during

voice

analysis

in

the

patients

without

any

nerve

monitoring.

The

endotracheal

tube

in

sizes

multi-parametric

of

neural

damages.

or

8.0

was

placed

in

contact

with

the

true

vocal

cords. probe

evidence

7.0 For was

identification

of

the RLN,

a monopolar

stimulator

used event

with

an

initial

stimulation

level

of

1.0 mA,

and

Materials & methods

2.

threshold

was

set

at

100 m V.

Before

nerve strap

the

the

stimulator

probe

was

tested pulse

on

identification,

Subjects

2.1.

muscles

to

confirm

whether

the

probe

and

generator neuromus- intubation

working blocking

properly.

Furthermore,

additional following

were cular

retrospective

review

was

performed

with

a

total

of

A

agents

were

not

used

469 of Anam Hospital, Korea University, Seoul, South Korea between October 2012 and November 2014. Among these patients, 284 patients were excluded due to young age before 18 years, insufficient medical records, previous vocal cord paralysis or vocal fold lesion, planned recurrent laryngeal nerve sacrifice during operation, completion thyroidectomy, or combined lateral neck dissection. In addition, patients showing post- thyroidectomy evidence of RLN or EBSLN palsy and patients with anaplastic or medullary carcinoma of the thyroid were also excluded. Overall, 185 female patients met the inclusion criteria. The study group consisted of 68 retrospectively selected, consecutive patients who had undergone IONM thyroid surgery for papillary thyroid carcinoma between January 2014 and November 2014. A historical group of 117 similar patients who had not received IONM thyroid surgery for papillary thyroid carcinoma between October 2012 and December 2013 was used as an external control group. Based on the extent of thyroid surgery, all the patients were divided into four groups: hemi-thyroidectomy with IONM (Group A, n = 37) or without IONM (Group B, n = 41) and total thyroidectomy with IONM (Group C, n = 31) or without IONM (Group D, n = 76) ( Fig. 1 ). female patients who were referred to the thyroid center

the

operation.

during

2.3.

Voice

analysis

Pre-and post-operative evaluation of vocal cord motility was performed via 70-degree rigid endoscope in all cases. Subjects were assessed four times: before surgery and at 1 week, 1 month, and 3 months after surgery. The following were undertaken: acoustic analysis (measuring fundamental frequency, jitter, shimmer and noise to harmonic ratio), aerodynamic analysis (measuring mean flow rate, maximum phonation time and subglottic pressure), voice range profile (VRP) analysis, vocal assessment using the grade-roughness-breathiness-asthenia- strain scale, and assessment of the Voice Handicap Index. Acoustic variables were measured using the Multi- Dimensional Voice Program software application from the Computerized Speech Lab system (model 4500; KayPentax, Lincoln Park, New Jersey, USA), assessing a few seconds of sustained phonation of the vowel/a/. VRPs, including vocal pitch (frequency) range and vocal intensity range, were assessed to identify the maximum and minimum intensity (decibel, dB) and frequency (hertz, Hz) of the voiced sound. Subjective assessment of voice quality was performed using the grade-roughness-breathiness-asthenia-strain scale designed by De Bodt et al., [6] with additional assessment of aphonia. This assessment was performed by an experienced phonetician with no knowledge of the study design. The Voice Handicap Index (VHI) consists of 30 questions divided by content into 3 subscales covering functional, physical and emotional parameters. All patients completed a Voice Handicap Index questionnaire, using a five-point rating scale to indicate their response. The scale was ordinal and scored from 0 (meaning never) to 4 (meaning always) for each of the questions, with a minimum total score of 0 and a maximum total score of 120. Higher scores indicated worse perceived disability due to the patient ’ s voice problem.

Surgical

techniques

2.2.

open

thyroid

surgery,

a

standard

5 – 6

cm

transverse

In

incision was

performed

two

fingerbreadths

above

the

cervical sternal muscles

notch. Subplatysmal

skin

flaps were made

and

the

strap

were

divided

at

the

midline

and

retracted

laterally. capsular peripheral

identification

of

the

thyroid

gland,

careful

After

close

to

the

thyroid

was

performed

and

dissection

of

the

superior,

middle,

and

inferior

thyroid

vessels

ligation

performed

individually,

just

on

the

thyroid

capsule,

using

was

harmonic

shear.

In

endoscopic

or

robotic

thyroid

surgery,

a

a

cm

skin

incision

was

performed

on

the

axilla

for the

5 – 6

approach

and

a

7 – 8

cm

skin

incision

along

transaxillary

hairline

from

the

earlobe was

performed

for

the

retroauricular

skin

flap was

extended

to

the

anterior

neck

until

approach. The

2.4.

Statistics

contralateral

lobe

of

the

thyroid

was

exposed.

Harmonic

the

for vessel preserved

control.

In

all operations, RLNs were

results

of

voice

analysis

were

compared

between

The

shear was used

and

but

EBSLNs

were

not

routinely

with

and

without

IONM.

Statistical

analysis

was

identified

patients

112

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