Single-session high intensity focussed ablation (HIFU) versus open cervical hemithyroidectomy for benign thyroid nodule: analysis on early efficacy, safety and voice quality

Figures & data

Figure 1. Treatment screen. The central panel shows the top view reconstruction of the nodule which is made up of multiple white cycles. The empty circles represent the un-ablated subunits while the filled circles represent the ablated subunits.

Table 1. A comparison of baseline characteristics and voice quality between patients who underwent high intensity focussed ultrasound (HIFU) or hemithyroidectomy (surgery).

Variable	HIFU (n = 43)	Surgery (n = 103)	p value
Age at treatment (years)	47.9 ± 11.8	51.4 ± 15.7	0.016
Sex (Male:female)	2:41	28:75	0.003
Largest diameter of dominant nodule (cm)	3.6 ± 1.2	4.5 ± 1.5	<0.001
Nodule volume (cm^3)	5.15 ± 4.38	10.23 ± 9.97	<0.001
TSH (mIU/L)	1.4 ± 0.6	1.3 ± 1.3	0.701
Free T4 (pmol/L)	17.4 ± 1.5	17.8 ± 2.4	0.310
Mean F0 (Hz)	205.4 ± 36.8	188.1 ± 42.6	0.026
Minimum F0 (Hz)	154.0 ± 50.7	147.8 ± 48.2	0.501
Maximum F0 (Hz)	251.1 ± 53.3	228.2 ± 56.4	0.030
Jitter or pitch perturbation (%)	0.4 ± 0.3	0.4 ± 0.6	0.739
Shimmer or amplitude perturbation (%)	0.5 ± 0.4	0.5 ± 0.3	0.787
Noise-to-harmonic ratio (NHR)	0.04 ± 0.1	0.04 ± 0.1	0.927
Maximum phonation time (MPT) (s)	11.5 ± 6.6	10.2 ± 4.6	0.185
Total VHI-30 score	6.0 ± 7.9	6.6 ± 11.8	0.782
Mean VHI score per item	0.2 ± 0.3	0.2 ± 0.4	0.800

Abbreviations: F₀: fundamental frequency; VHI: Voice Handicap Index.

*Bold signifies statistical significance (p < 0.05).

Figure 2. The ultrasound images obtained at baseline, 1-month and 6-month.

Table 2. A comparison of treatment efficacy and safety between the HIFU and surgery groups.

	HIFU (n = 43)	Surgery (n = 103)	p value
Treatment parameters (range)
- Total energy delivered (KJ)	14.17 ± 5.44	–	–
- Total duration of treatment (min)	55.20 ± 30.10	57.1 ± 15.3	0.286
Pain scores by visual analogue scale
- During treatment	3.5 ± 4.0	–	–
- Immediately after treatment	1.0 ± 1.0	–	–
- Before hospital discharge	0.0 ± 1.0	–	–
Skin burn (%)	0 (0.0)	–	–
Recurrent laryngeal nerve injury^a (%)	1 (2.3)	3 (2.9)	1.000
Subclinical hypothyroidism^b (%)	1 (2.3)	21 (20.4)	0.008
Hypothyroidism (FT4 < 12 pmol/L) (%)	0 (0.0)	0 (0.0)	–
Hospital stay (d)	0.3 ± 0.2	1.0 ± 0.0	<0.001
Size/volume of index nodule (mL)
- Baseline	5.15 ± 4.38	10.23 ± 9.97	<0.001
- 1-week	5.31 ± 4.46	–	–
- 1-month	4.23 ± 3.58	–	–
- 6-month	2.54 ± 2.28	–	–
Volume reduction from baseline
- 1-week (%)	−3.05 ± 4.63	–
- 1-month (%)	17.84 ± 5.56	–
- 6-month (%)	51.71 ± 16.04	–
WHO nodule grade at 6-month
- Grade 1a (palpable but not visible when neck is extended)	29 (67.4)	–
- Grade 1b (palpable and visible when neck extended)	11 (25.6)	–
- Grade 2 (visible when neck is in the normal position)	3 (7.0)	–
- Grade 3 (visible from distance)	0 (0.0)	–
Symptom improvement score			0.009
- 0 (no improvement)	3 (7.0)	10 (9.7)
- 1 (slight improvement)	2 (4.7)	22 (21.4)
- 2 (moderate improvement)	8 (18.6)	31 (30.0)
- 3 (significant improvement)	29 (67.4)	40 (38.8)

^a Transient (i.e. complete vocal cord recovery within 6 months of treatment). No permanent injury in either group.

^b Defined as serum thyroid-stimulating hormone (TSH) exceeding 4.78 mIU/L within the first 6 months following treatment.

*Bold signifies statistical significance (p < 0.05).

Table 3. A comparison of the difference in acoustic parameters and VHI between baseline and post 1-month.

	HIFU (n = 42)		Surgery (n = 100)		Linear regression (unadjusted)
Variable	Baseline	1-month	Baseline	1-month	Coeff.	95%CI	p value
Mean F0 (Hz)	205.4 ± 36.8	212.7 ± 44.5	188.1 ± 42.6	182.2 ± 46.2
Difference in mean F0 (Hz)	7.2 ± 32.5		−6.2 ± 26.5		13.47	2.90 – 24.05	0.013
Minimum F0 (Hz)	154.0 ± 50.7	167.3 ± 57.4	147.8 ± 48.2	135.3 ± 48.9
Difference in min. F0 (Hz)	13.3 ± 52.3		−13.2 ± 41.5		26.52	9.80 to 43.25	0.002
Maximum F0 (Hz)	251.1 ± 53.3	257.1 ± 57.7	228.2 ± 56.4	238.2 ± 63.2
Difference in max. F0 (Hz)	6.1 ± 55.0		13.2 ± 56.7		−7.14	−28.05 to 13.78	0.501
Jitter (%)	0.4 ± 0.3	0.3 ± 0.3	0.4 ± 0.6	0.5 ± 0.5
Difference in Jitter (%)	−0.07 ± 0.20		0.15 ± 0.65		−0.22	−0.43 to 0.01	0.038
Shimmer (%)	0.5 ± 0.4	0.5 ± 0.4	0.5 ± 0.3	0.6 ± 0.4
Difference in Shimmer (%)	−0.05 ± 0.32		0.08 ± 0.35		−0.13	−0.26 to 0.00	0.044
NHR	0.04 ± 0.1	0.03 ± 0.1	0.04 ± 0.1	0.06 ± 0.1
Difference in NHR	−0.015 ± 0.054		0.015 ± 0.086		−0.03	−0.06 to 0.00	0.044
MPT (s)	11.5 ± 6.6	10.1 ± 5.6	10.2 ± 4.6	9.5 ± 5.7
Difference in MPT (s)	−1.4 ± 5.0		−0.7 ± 8.1		−0.71	−3.44 to 2.03	0.609
Total VHI-30 score	6.0 ± 7.9	10.8 ± 18.0	6.6 ± 11.9	16.0 ± 20.1
Difference in total VHI-30	4.8 ± 19.5		9.77 ± 20.2		−4.65	−12.08 to 2.78	0.218
Mean VHI-30 score per item	0.2 ± 0.3	0.4 ± 0.6	0.2 ± 0.4	0.5 ± 0.7
Difference in mean VHI score per item	0.16 ± 0.65		0.32 ± 0.69		−0.16	−0.41 to 0.10	0.228

Abbreviations: F₀: fundamental frequency; NHR: noise-to-harmonic ratio; VHI: Voice Handicap Index.

*Bold signifies statistical significance (p < 0.05).