Ultrasound-Controlled Cryoneurolysis for Peripheral Mononeuropathies: A Retrospective Cohort Study

Figures & data

Figure 1. Study flowchart.

Figure 2. Ultrasound-guided cryoneurolysis of the left greater auricular nerve in the lateral position.

Zoom indicates the sterile surgical field. The cryoprobe is in the right hand of the operator.

Figure 3. Transverse ultrasound image of the superficial radial nerve in the middle (N) before and during cryoneurolysis.

An ‘ice ball’ (arrow) is formed at the tip of the cryoprobe in the area of the superficial radial nerve ramus.

A: Radial artery; MBrR: Brachioradialis muscle; N: Superficial radial nerve.

Table 1. Patient baseline characteristics and demographics.

Variable	Patient group (n = 24)
Age at intervention (years)
Mean (SD)	58.92 (±15)
Sex, n (%)
Male	11 (46%)
Female	13 (54%)
Pain duration (months)
Mean (SD)	38.25 (±50)
Baseline pain level
Mean (SD)	5.8 (±1.8)
Median (IQR)	6 (4–7)
Neuropathy (nerve)
Subcostal nerve	2 (8%)
Ilioinguinal/hypogastric nerve	4 (16%)
Intercostal nerve	9 (38%)
Greater auricular nerve	1 (4%)
Digital palmar nerve	1 (4%)
Suprascapular nerve	1 (4%)
Saphenous nerve	2 (8%)
Superficial peroneal nerve	2 (8%)
Greater occipital nerve	1 (4%)
Superficial radial nerve	1 (4%)
Previous drug therapy
Opioids	13 (54%)
Anticonvulsants	17 (71%)
Antidepressants	15 (63%)
Lidocaine patches/capsaicin	13 (54%)

IQR: Interquartile range; SD: Standard deviation.

Table 2. Pain level before and after cryoneurolysis during the 6-month observation period.

Observation	n (%)	Pain level: mean (SD)	z-value	p-value
Baseline	24	5.8 ± 1.8	–	–
Follow-up, 1 month	24	3.4 ± 2.6	-3.16	< 0.001
Responder	13 (54.2%)	1.5 ± 1.3	-4.27	< 0.001
Nonresponder	11 (45.8%)	5.6 ± 1.9	-0.06	0.486
Follow-up, 3 months	22	5.4 ± 2.1	-0.34	0.371
Responder	3 (13.6%)	2.7 ± 3.1	-1.71	0.2
Nonresponder	19 (86.4%)	5.8 ± 1.7	0	0.51
Follow-up, 6 months	22	5.5 ± 2.0	-0.22	0.414
Responder	2 (9.1%)	3.0 ± 4.2	-0.77	0.33
Nonresponder	20 (90.9%)	5.8 ± 1.7	0	0.512

The p- and z-values refer to the Wilcoxon rank-sum test results. However, for ease of reference, the mean numerical rating scale scores are reported.

SD: Standard deviation.

Figure 4. Pain intensity of initially 24 patients before and after cryoneurolysis.

0 m = before, 1 m = after 1 month, 3 m = after 3 months, 6 m = after 6 months. The box and whisker plots show the median, first and third quartiles and 10–90% percentiles. Wilcoxon rank-sum test to compare groups.

***p < 0.001.

m: Months; NRS: Numerical rating scale, ns: Not significant.

Figure 5. Pain intensity for all responders before and after cryoneurolysis.

0 m = before, 1 m = after 1 month, 3 m = after 3 months, 6 m = after 6 months. The box and whisker plots show the median, first and third quartiles and 10–90% percentiles. Wilcoxon rank-sum test to compare groups.

***p < 0.001.

m: Months; NRS: Numerical rating scale, ns: Not significant.