The study aimed to determine if changes in voice after total thyroidectomy are related to the weight and volume of the removed thyroid gland. It found that a larger thyroid mass was associated with more transient changes to the speaking fundamental frequency range and intensity range after surgery. Both weight and volume of the gland had a statistically significant effect on these voice parameters. While vocal cord function alone could not explain voice changes after thyroidectomy, the changes were found to be transient in nature. The study provides insight into factors beyond the recurrent laryngeal nerve that influence post-operative voice quality.

1. Contribution of weight and volume of the
extirpated thyroid gland on voice alterations after
total thyroidectomy in patients with papillary
carcinoma thyroid
Published in : Journal of voice, February 2020
By: Department of head and neck , Tata Medical Centre Kolkata

2. INTRODUCTION
-Most common endocrine malignancy- PTC comprises 80%
-Mainstay of treatment- Surgery followed by Radio-Iodine ablation
-Incidence of permanent RLN palsy -estimated to be < 2%.*
-Voice change after thyroid surgery is common despite preservation
of laryngeal nerves.
*Finck C (2006) Laryngeal dysfunction after thyroid surgery: diagnosis, evaluation and treatment. Acta Chir Belg
106:378-387

3. Intubation trauma
Cricothyroid dysfunction
Local pain in neck
Faulty speech due to enlarged
thyroid gland
Psychological reaction to
postoperative situation
Extra-laryngeal frame factors
Laryngotracheal fixation with
vertical movement impairment
Extrinsic laryngeal muscle
malfunction
Apart from nerve injury, other causes of voice change

5. REVIEW OF LITERATURE
Debruyne et al.*
-sample of 47 - who underwent a thyroidectomy
without RLN impairments
-loss of up to 2 semitones in 17% of the patients.
*Debruyne F et al.(1997) Acoustic analysis of the speaking voice after thyroidectomy. J Voice 11:479-
482.

6. McIvor et al.*
-prospectively studied 44 patients
-worsening in voice in 23% of the cases
*Mclvor NP et al. (2000) Thyroid surgery and voice related outcomes. Aust N Z J Surg 70:179-183
REVIEW OF LITERATURE

7. Sinagra et al.*
-84% of objectively defined dysphonias.
-30% mentioned subjective vocal change symptoms (especially a
decrease in tone and intensity, as well as vocal fatigue)
*Sinagra DL, et al. Voice changes after thyroidectomy without recurrent laryngeal nerve injury (2004)
JAm Coll Surg 199:556-560. doi: 510.1016/j.jamcollsurg.2004.1006.1020.
No articles in literature to explain the association between the weight and
volume of thyroid gland and change in voice after thyroidectomy.
REVIEW OF LITERATURE

8. AIM
To find if change in voice after total
thyroidectomy is related to the weight
and volume of the removed thyroid
gland

9. Study type Prospective cohort study
Duration December 2016 - May 2018
Number of patients 50
Included patients PTC who underwent total thyroidectomy +/-
central and lateral compartment neck
dissection
Study Design

10. Study
Patients diagnosed with Papillary Ca Thyroid
Informed consent
clinical examination and stroboscopic examination
Speech Analysis
Day prior to surgery 1 month after Surgery 3 month after surgery

11. • Clinical examination
• Stroboscopic examination
Before surgery
• Day before surgery
• 1 and 3 months after surgerySpeech analysis
• Total thyroidectomy with/without central or lateral
neck dissection
• Use of monopolar/bipolar near nerves
• Integrity of nerves assessed by direct visualisation
Surgery

12. Inclusion criteria
Total thyroidectomy for papillary ca thyroid.
Exclusion criteria
 Pathology other than Papillary thyroid ca
 Vocal dysfunction pre-operatively
 Non identification of recurrent/superior
laryngeal surgery
 Vocal cord dysfunction after surgery

13. Points evaluated
Speaking Fundamental Frequency
(SFo)
Range of frequency
Speaking intensity
Range of intensity
Glottal to Noise Excitation (GNE)
Vagmi Voice Diagnostics Version 8.1

14. -Subjective voice analysis:
Questionnaire to quantify the functional, physical and emotional impacts of
a voice disorder on a patient's quality of life
Voice Handicap Index (VHI)

15. Weight An electronic weighing scale
with a readability of 1g
Volume Volume of the displaced saline
after complete immersion of
the gland

16. RESULTS
50 patients consented and
scheduled
Final analysis 29 patients
RLN sacrificed 2
patients
12 patients showed VC
dysfunction on scopy
2 patients lost on follow
up
1 patient developed
brain mets
1 patient final biopsy not
PTC
1 patient accurate
weight and volume
could not be done 2 patients underwent
hemithyroidectomy

17. Factor Median Range
Age (Years) 31 18-64
Weight of the thyroid gland (g) 16 5-42
Volume of the thyroid gland (ml) 10 5-32
Preoperative fundamental frequency (Hz) 227.37 111.85- 302.49
Preoperative frequency range (Hz) 58.51 7.76- 138.70
Preoperative mean intensity (dB) 104.59 92.25- 191.00
Preoperative intensity range (dB) 11.58 2.11- 30.32
Preoperative GNE –G ratio (-2.38) (-8.18) – (-0.45)
Preoperative GNE – L ratio 0.76 0.39- 0.95
Preoperative VHI 0 0-4
Postoperative VHI 8 0-80
Categorical Variables:
Factor Performed (%) Not performed (%)
Cutting strap muscles 5 (17.24%) 24 (82.76%)
Central compartment dissection 19 (65.52%) 10 (34.48%)

18. Comparison between preoperative and postoperative voice parameters at 1
month
Factor Mean Change (Standard
Deviation)
‘p’ value
Fundamental frequency (Hz) 17.21 (34.49) 0.012
Range of frequency (Hz) -16.52 (52.34) 0.100
Mean intensity (dB) 5.54 (18.21) 0.112
Range of intensity -7.14 (14.29) 0.012
GNE –G ratio 0.12 (2.64) 0.809
GNE- L ratio 0.01 (0.17) 0.804
VHI -11.03 (14.49) <0.001

19. Effect of weight and volume of thyroid gland on voice parameters.
Factor Median change
[Range]
Univariate Analysis* Multivariate
analysis*
Weight Volume Weight Volume
Fundamental
frequency (Hz)
12.65
[(-38.10) – 129.66]
0.882 0.780 0.870 0.607
Range of
frequency (Hz)
(-11.85)
[(-106.02)- 134.79]
0.007 0.382 0.002 0.035
Mean intensity
(dB)
1.86
[(-24.45) – 89.49]
0.470 0.973 0.875 0.974
Intensity range
(dB)
(-2.82)
[(-33.35) – 19.39]
0.428 0.295 0.014 0.008
GNE– G 0.12
[(-6.46) – 5.60]
0.364 0.574 0.707 0.573
GNE- L 0.01
[(-0.43) – 0.38]
0.418 0.590 0.429 0.389
VHI 8 [0-76] 0.758 0.609 0.279 0.707

20. Comparison between preoperative and postoperative voice parameters after 3
months (n=16)
Factor Median [Range] ‘p’ value
Fundamental frequency (Hz) 216.00 [113.11 – 279.03] 0.991
Range of frequency (Hz) 80.04 [3.91 – 138.98] 0.150
Mean intensity (dB) 108.72 [86.30- 116.89] 0.424
Range of intensity 14.80 [4.70- 33.20] 0.852
GNE –G ratio -2.56 [(-8.87) – (-0.81)] 0.434
GNE- L ratio 0.74 [0.36- 0.91] 0.495
VHI 0 [0-3] 0.617

21. Lateral neck
dissection
Age (Univariate
analysis)
Age (Multivariate
analysis)
Gender
Range of intensity
(p= 0.033)
Mean Intensity
(p<0.001)
Mean Intensity
0.005)
VHI (p= 0.048)
GNE G Ratio
(p= 0.004)
GNE- G
(p= 0.001)
GNE- G
(p= 0.004)
GNE L ratio
(p= 0.003)
GNE- L
(p= 0.001)
GNE- L
(p= 0.003)
Other factors affecting speech

22. Discussion
 Voice is a complex multidimensional phenomenon, due to
vocal cord vibration and sound generation due to expiratory
flow and subjective psychological auditory phenomenon.
 Author’s primary objective of the study to defy a long
standing concept of relying on just examining vocal cord
mobility after thyroidectomy for evaluation of phonic abilities
in person.

23. Reference studies ( conclusion )
 Sonienen et al
The function of the extrinsic laryngeal muscles, the so called external frame function, lengthens or
shortens the vocal folds changing the relationship of the thyroid to the cricoid cartilage.
 Hong et al
The contraction of the sternohyoid and sternothyroid muscles causes a laryngotracheal downward pull,
producing a high volume of air in the subglottic space, corresponding to increased subglottic pressure.
This downward pull shortens the cricothyroid distance, and anterior downward bending shortens of the
anterior cricothyroid distance, which lengthens the vocal folds and raises the frequency.

24.  Phonation time and fundamental frequency were not altered after
surgery, but the speaking fundamental frequency (SFo), range of SFo
and vocal range might diminish after surgery.
 Both of these studies suggested that :
The cause of voice dysfunction could not be attributed to a neural
lesion but may be due to a disturbance of the extra-laryngeal
frame function.

25. Significant observations
 Multivariate analysis to study effect of weight and volume of
the thyroid gland to have a statistically significant effect on
range of frequency and the range of intensity.( P value
significant for range and intensity of voice)
 Increase in weight and volume of the thyroid gland is
associated with more lateral traction on the strap muscles
during thyroidectomy.

26.  Ageing has been associated with a loss of muscle mass, directly
resulting in diminished muscle function.
 Increase in weight and volume of thyroid gland caused more
lateral traction on strap muscles during thyroidectomy.
Lateral neck dissection may alter voice:
Reason increase in neck stiffness explain change in intensity of
voice

27.  Author’s observation has also suggested that voice change after
thyroidectomy is transient in nature .
 Speech therapy and steroid use could have possible positive effects
on patients, there role should be further evaluated

28. Discussion
-Statistically significant change in the SF0, range of intensity and
the VHI scores.
-Weight and volume had an effect on range of frequency and the
range of intensity.
Age affected the mean intensity
-Voice change was transient in nature

29. Strengths
 Introduction, background and need for study are explained in detail.
 Method of data collection and statistical methods are properly explained
in methodology.
 Results are presented in tabular form , observations explained in detail (
univariate and mutivariate analysis), P-value mentioned.
 Finding and interpretation are clearly mentioned with relevant references

30. Limitations
-Small number of patients.
-Periodic, long term follow up voice assessment to evaluate the recovery of voice
over a period of time with changes in tissue pliability ,though ideal, has not been
performed.
-Electromyography of cricothyroid muscle is required for assessment of Superior
laryngeal nerve function which is not available in our institute.
 P-value is non –significant in many observations

31. CONCLUSION
-Larger thyroid mass causes transient change in voice quality
after thyroidectomy.
-Mere examination of the functional integrity of the
neuromuscular function of the vocal cords is not sufficient for
voice assessment after thyroidectomy.

32. THANK YOU
Thank you