Relevant Biological Effects of Varicocele Embolization with N-Butyl Cyanoacrylate Glue on Semen Parameters in Infertile Men

Abstract

Surgical treatment or varicocele embolization (VE) with sclerosing or mechanical embolic agents have been shown to improve the semen parameters of infertile men. The aim of this study was to evaluate the impact of VE using N-butyl cyanoacrylate (NBCA) glue on semen parameters in infertile men. From January 2014 to June 2018, infertile adult patients with stage 3 varicocele and an initial semen analysis showing at least one abnormal semen parameter, and who were successfully embolized with NBCA Glubran^®2 glue, were retrospectively recruited. The availability of a second semen analysis after VE was mandatory for patient inclusion. The primary endpoint was the change in total sperm number (TSN) after VE. The other parameters of interest were progressive and total sperm motilities (Smot) at 1 h (H1), sperm vitality (SV) and morphology (SMor). One hundred and two patients were included. Eight patients presented null TSN before and after VE. Among the remaining 94 patients, a significant improvement in the median TSN after VE was shown (31.79 × 10⁶/ejaculate [IQR: 11.10-127.40 × 10⁶/ejaculate] versus 62.24 × 10⁶/ejaculate [IQR: 17.90-201.60 × 10⁶/ejaculate], p = 0.0295). Significant improvement in TSN was found for the 60 oligo- or azoospermic patients (p = 0.0007), whereas no significant change was found for the 42 patients with normal initial TSN (p = 0.49). Other parameters, such as progressive and total SMot, SV and SMor, also significantly improved after VE (p = 0.0003, 0.0013, 0.0356 and 0.007, respectively). The use of NBCA glue as an embolic agent for VE in infertile men with stage 3 varicocele significantly improves the semen parameters.

Keywords: NBCA; azoospermia; embolization; glue; infertility; lipiodol; oligospermia; sperm; varicocele.

Figure 1

Example of typical bilateral varicocele embolization (VE) procedure using NBCA-MS Glubran^®2. (a) Left gonadal vein venography through a 5-French Cobra catheter by transvenous femoral approach. (b) Right gonadal vein venography after VE of the left gonadal vein using Glubran^®2-Lipiodol^® mixture at a 1:1 ratio. (c) Plain X-ray image after bilateral VE using Glubran^®2-Lipiodol^® mixture at a 1:1 ratio. In more detail, a microcatheter is placed below the iliopectinal line and the dead space is filled with 5% dextrose solution to avoid intracatheter glue polymerization. The embolization procedure is then performed using glue mixed with Lipiodol at a ratio of 1:1. Glue–Lipiodol mixture is then injected under strict fluoroscopic guidance, with continuous injection performed manually and a display of real-time distribution. The glue injection begins in the distal intrapelvic segment of the gonadal vein, and the catheter is withdrawn slowly while injecting NBCA-MS under fluoroscopy. Injection is then stopped before the pampiniform plexus is reached. The microcatheter is then removed when the glue fills the venous space selected beforehand. Here we can see the cast of glue along the left and right gonadal veins after embolization.

Figure 2

Flow chart of patients’ selection. VE, varicocele embolization; NBCA-MS, n-butyl cyanoacrylate metacryloxysulfolane.

Figure 3

Box plots showing the total sperm number (TSN, 10⁶/ejaculate) before (T1) and after (T2) varicocele embolization with Glubran^®2. (a) Evolution of TSN in all patients (n = 102) between T1 and T2 showing a significant improvement (p = 0.029); (b) Evolution of TSN in patients with initial abnormal TSN (n = 60) showing a significant improvement (p = 0.0007); (c) Evolution of TSN in patients with normal initial TSN (n = 42) with no significant change between T1 and T2 (p = 0.49).