Table 2.

Modified Johansen scale polyp sizes. Results are shown as median (P₂₅–P₇₅).

Polyp size	Right	Left	Total
Pre-treatment (n = 19)	1 (1–2)	1 (1–2)	3 (2–4)
Post-treatment (n = 17)	1 (0.5–1.5)	1 (0.5–2)	2 (2–2.5)
Statistical differences after treatment	p = 0.020	p = 0.023	p = 0.009
Effect sizes from the differences	r =  − 0.400 Medium effect size	r =  − 0.389 Medium effect size	r =  − 0.528 Large effect size

Three patients showed complete polyp regression after treatment (score result = 0). All post-treatment changes were statistically significant (see text).