aerodynamic phonatory pattern as a new sign of …...branch of the superior laryngeal nerve (ebsln)...
TRANSCRIPT
Aerodynamic Phonatory Pattern as a New Sign
of Superior Laryngeal Nerve
Secundino Fernandez, MD, PhD (presenter); Juan M. Alcalde, MD, PhD; Peter M. Baptista, MD, PhD;
Luz Barona MD. Otolaryngology Department, Universidad de Navarra, Pamplona, SPAIN.
INTRODUCTION
RESULTS
Table 1. Group B subglottal pressure values. P<0.02
Figure 1. Rothemberg Mask
Figure 2. Example of acoustic and aerodynamic measurements
ABSTRACT
METHODS AND MATERIALS
DISCUSSION-CONCLUSIONS
REFERENCES
CONTACT
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Reduced quality of life after thyroid
surgery is multifactorial and may
include the need of lifelong different
treatments. About 1 in 20 patients
experience voice changes, and it is
very frequent that these changes
may not be caused by neural lesions.
We studied 58 thyroidectomized
patients with neither apparent neural
cause of thyroidectomy-related
dysphonia nor recurrent laryngeal
nerve injury nor external
branch of the superior laryngeal
nerve (EBSLN) injury. Afterward,
acoustic and aerodynamic measure-
ments were made.
We describe 2 different groups of
patients with different aerody-namic
pattern in voice production that
correlates with voice quality. In 66%
of patients there was no change and
in 34% the glottal pressure and
laryngeal resistance decreased as a
result of lower tension in the vocal
fold as a consequence of an injury of
the EBSLN.
This aerodynamic phonatory pattern
that may be understood by objective
aerodynamic measurements could
be another new sign of EBSLN injury. Maximum phonation time, speech rate and
articulation rate were also registered. All
measurements were made using Voice Plus from
Alamed Corporation software. Recording was done
in the Voice Research Laboratory (a quiet non-
sound treated room approximately 5*4m) at the
Otolaryn-gology Head and Neck Surgery
Department of the University of Navarra. The four
Signals pressure, flow, sound pressure-microphone,
electroglo-ttograph were digitized by an A/D
converted board (DT 2821). The digitized signal
was imported to the Alamed Voice Plus Analysis
System on a PC for the aerodynamic study. The
acoustic analysis was ma-de with SoundSope on
G4 Mac computer. Intensity was evaluated with a
sonometer or sound level meter. STATA software
was used to analyze variables.
We studied 58 thyroidectomized patients with
neither apparent neural cause of thyroidectomy-
related dysphonia nor recurrent laryngeal nerve
injury nor external branch of the EBSLN injury.
The patients were asked to produce sustained
vowels, syllables, and sentences. Three items
were recorded in upright and sitting positions.
We ask every patient for a sustained phonation
of Spanish vowels /a/ & /i/.
The syllables: /pa/ & /pi/ and two sentences: “Papá pinta la pared de color púrpura con la pintura
que compró por la tarde”
“El domingo por la mañana voy a la bodega de mi
hermano, a mediodía mi hermano y yo bebemos vino”.
During each task the subject held the pneumo-
tachograph mask (Rothemberg Mask) firmly in
place over the nose and mouth with the pressure
tube between the lips (Figure1). Acoustic and
aerodynamic measurements were made:
fundamental frequency, jitter, shimmer, intensity,
harmonic/noise ratio, spectrographic analysis,
subglottic pressure, mean transglottic flow, and
laryngeal resistance (Figure 2).
Postoperative voice changes may be an impor-
tant part of the outcome of the patients
undergoing thyroidectomy. Deterioration and
amelioration of acoustic parameters can be
observed, and those changes may occur
differently among male and female patients.
Physicians should take the patient’s sex into
consideration when informing the patient about
possible voice alterations after thyroidectomy.
Preoperative and postoperative acoustic and
aerodynamic analyses may be helpful in
revealing any voice abnormality already
present before the surgery and any possible
alteration occurring after the surgery.
Aerodynamic phonatory pattern charac-terized
by subglottal pressure and laryngeal
resistance decreased as a result of lower
tension in the vocal could be a new sign of
EBSLN injury.
Reduced quality of life after thyroid surgery is
Multifactorial and may include the need of
lifelong different treatments. Studies have shown
that subjective voice disturbance after thy-
roidectomy is very common, even without injury
to the recurrent laryngeal nerves.
One possible cause for postoperative dysphonia
is injury to the external branch of the superior
laryngeal nerve (EBSLN). The EBSLN supplies
the cricothyroid muscle, which acts to lengthen
the vocal folds during phonation. Post-
operatively, patients with a lesion of the EBSLN
typically complain of voice fatigue, problems
reaching high-pitch sounds that they were used
to reach, and the need of an extra effort to
speak; they can also complain of various rates of
dysphagia. The awareness to these symptoms,
that may be subliminal to common people, might
be more evident to the so-called “professional
speakers”.
Several studies have investigated post-operative
rates of EBSLN injury varying from 0 to as much
as 58% a result that reflects the need for
standardized protocol slooking forward a more
accurate evaluation of this complication, even if
the impairments coming from such lesions are
the less prone to be improved with specific
postoperative treatments. Currently, videostro-
boscopy and/or electromyography of the crico-
thyroid are the only instrumental tools that might
allow to achieve good diagnostic standards
although both are invasive methods, responsible
for some discomfort to the patients.The purpose
of this study is to describe aerodynamic
phonatory features in thyroidectomized patients
in order to determine what mechanisms are
involved in voice changes in these patients and
what are the best rehabilitative options.
1. Lombardi CP, Raffaelli M, D’Alatri L, et al. Voice and
swallowing changes after thyroidectomy in patients without
inferior laryngeal nerve injuries. Surgery. 2006;
140(6):1026-1032.
2. Sinagra DL, Montesinos MR, Tacchi VA, et al. Voice
changes after thyroidectomy without recurrent laryngeal
nerve injury. J Am Coll Surg. 2004;199(4):556-560
3. Cernea CR, Ferraz AR, Furlani J, et al. Identification of the
external branch of the superior laryngeal nerve during
thyroidectomy. Am J Surg. 1992;164(6):634-639.
4.Varaldo E, Ansaldo GL, Mascherini M, et al. Neurological
complications in thyroid surgery: a surgical point of view on
laryngeal nerves. Front Endocrinol (Lausanne). 2014 Jul
15;5:108
Name: Secundino Fernandez
Org.: Universidad de Navarra
Email: [email protected]
Phone: +34 948255400 ext.(4681)
Website: www.unav.es
We describe 2 different groups (Figures 3 &4) of
patients with different aerodynamic pattern in voice
production that correlate with voice quality.
In 66% of patients there was no change (group A)
and in 34% (group B) the glottal pressure and
laryngeal resistance decreased as a result of lower
tension in the vocal fold as a consequence of an
injury of the EBSLN (Table 1).
Subglottic pressure
(mm H2O) Mean Std-error Lower Upper
Pre Thyroidectomy 93.27 4.48 84.26 120.29
Post Thyroidectomy 72.43 4.22 63.94 80.93
/pa/…/pa/…/pa/…
Figure 4. Example of aerodynamic pattern Group B.
Figure 3. Example of aerodynamic pattern Group A.