A Modified Transversal Two-Suture Microsurgical Intussusception Vasoepididymostomy for the Treatment of Epididymal Obstructive Azoospermia

Azoospermia is defined as the complete absence of sperm in the semen and affects 10–15% of infertile men [1]. Approximately 40% of azoospermia patients belong to obstructive azoospermia (OA) [2, 3], which is primarily caused by obstruction of vas deferens-epididymis connection or epididymal tubule [4]. Microsurgical treatment is an optimal option for the treatment of OA, which involves anastomosis of the seminal tract to bypass the obstruction [5]. Although various assisted reproductive techniques are adopted more and more widely, microsurgical treatment remains the first choice for some OA. Accumulating evidence has suggested that microsurgical technology is a more cost-effective option for OA as compared with assisted reproductive techniques [6‒10]. However, this microsurgical procedure is heavily dependent on surgical skill and is the most challenging procedure of all urological microsurgeries [11]. The modification of surgical procedures to improve success rate is helpful for their clinical promotion.

Between January 2009 and January 2020, we had performed a modified vasoepididymostomy procedure and followed up postoperatively, namely “fenestrated” transversal two-suture microsurgical intussusception vasoepididymostomy. The purpose of this study was to investigate the therapeutic efficacy and outcome of the “fenestrated” transversal two-suture microsurgical intussusception vasoepididymostomy for OA.

From January 2009 to January 2020, 64 patients with OA underwent the fenestrated transversal two-suture microsurgical intussusception vasoepididymostomy in our hospital. The inclusion criteria were as follows: (1) the sperm could not be detected in at least two routine semen analysis and one centrifugal microscopy analysis (1,500 g × 15 min); (2) serum sex hormone levels were normal; and (3) seminal plasma biochemical analysis suggested OA due to epididymal obstruction, with fructose level within normal range. This study was approved by the Institutional Review Board of Shenzhen People’s Hospital (No. LL-KY-2021641), and written informed consent was waived by the IRB due to the retrospective nature of this study.

All patients underwent combined spinal-epidural anesthesia, and a longitudinal incision was made in the middle of the scrotum. After the testis was free, the vas deferens was transversally cut to expose the vas deferens lumen. A venous indwelling needle (0.7 × 19 mm) was inserted into the lumen of the vas to inject saline toward the distal end of the seminal tract. No resistance to saline injection indicated the vas deferens was patency.

Under the microscope (magnification 18–20×), the distal epididymal tubule was dissected free, the epididymal tubule wall was gently lifted by the microscopic forceps, and part of the epididymal tubule wall was cut off by the microscissor to create a “window” (the diameter of the “window” should be approximately equal to the inner diameter of the vas deferens). The sampling of epididymal tubule fluid was used to search for sperm under a high-power optical microscope. If no sperm was found, the epididymis was explored from the tail to the head. If sperm was seen, intussusception anastomosis could be performed regardless of sperm motility.

The distal vas deferens was carefully mobilized to ensure that it can be anastomosed without tension (Fig. 1a). The procedure is similar to the currently used technique transverse 2-suture intussusception vasoepididymostomy but with modifications. First, instead of a transversely linear incision in the loop of the epididymal tubule, a round tubulotomy was created between two transverse sutures using microsurgical curved scissors (Fig. 1b). The diameter of the round tubulotomy was matched to the diameter of the vasal lumen. Second, sutures placed in the wall of the vas deferens were full thickness, which allowed a deeper invagination of the epididymal tubule into the vasal lumen (Fig. 1c), and then the outer muscular layer of the vas deferens was fixed to the epididymal tunic (Fig. 1d).

At 1, 3, 6, 9, and 12 months after surgery, patients were followed up for the semen analysis to check for the presence or absence of sperm. Meanwhile, the spouse’s pregnancy status was investigated.

A total of 64 azoospermia patients underwent microsurgical transversal two-suture intussusception vasoepididymostomy; the mean age was 31 years (range: 21–42 years). The course of disease ranged from 0.5 to 14 years. Among them, 45 received bilateral microsurgical transversal two-suture intussusception vasoepididymostomy, while 19 underwent unilateral vasoepididymostomy. Nine cases used to have their spouse/sexual partner’s natural conception, 21 cases had a history of reproductive tract infection, and one case had a history of inguinal hernia surgery.

The outcomes of bilateral microsurgical two-suture transversal intussusception vasoepididymostomy were summarized in Table 1. Among 45 patients who underwent bilateral surgery, 40 cases continuously showed motile sperm in the postoperative semen analysis. The patency rate was 88.89%, and 13 cases (28.89%) had their spouse’s successful conception. Regarding the timing of patency, 10 cases showed motile sperm in the semen analysis 1 month after the operation, 2 cases at 2 months after the operation, 7 cases at 3 months after the operation, and the other 2 cases at 6 months and 7 months after the operation, respectively.

The outcomes of unilateral microsurgical two-suture transversal intussusception vasoepididymostomy were summarized in Table 2. Of the 19 patients undergoing unilateral surgery, 13 cases (68.42%) showed motile sperm in the postoperative semen analysis, 1 case (7.69%) had a recurrence of obstruction, and 4 cases (21.05%) had their spouse’s successful conception. Regarding the timing of patency, 4 cases showed motile sperm in the semen analysis 1 month after the operation and the other 2 cases at 6 months and 18 months after the operation, respectively.

The earliest vas deferens and epididymis anastomosis were attempted by Martin et al. [12] in 1903. In 1918, Lespinasse [13] completed the first formal vasoepididymostomy. In 1978, Silber [14] developed the end-to-end microanastomosis of a single epididymal tubule and vas deferens under microscopic surgery. In 1980, Wagenknecht et al. [15] performed the microsurgical end-to-side anastomosis of the vas deferens and epididymal duct for the first time, and this end-to-side anastomosis technique was further promoted and popularized by Thomas [16] in 1987. In 1991, Stefanovic et al. [17] introduced the single-needle intussusception technique based on the end-to-side anastomosis technique in rats, which was clinically applied by Berger [18] in 1997 and achieved a potency rate of 92%. In 2000, Marmar [19] proposed the transversal two-suture microsurgical intussusception technique.

In the 2000s, Chan et al. [20] and his coworkers reported a novel longitudinal two-needle intussusception vasoepididymostomy which greatly simplifies the surgical procedure and achieves a higher potency rate as compared with the conventional three-suture triangulation, end-to-end, and end-to-side anastomoses methods [21]. The advantages of this method are as follows: first, the method of longitudinal cutting and longitudinal four-suture makes the anastomosis larger with better patency. Second, this suture method makes the anastomoses form a good impermeable layer, which greatly reduces the occurrence of semen granulomas [22]. At present, the potency rate following vasoepididymostomy ranges between 31–92%, the postoperative pregnancy rate ranges between 10–50%, and the recurrence rate of an obstruction within 1 year after surgery is 4% [23‒26].

The fenestration technique described in this study uses the “fenestrated” transversal two-suture method in the end-to-side intussusception anastomosis. The “fenestration” means the removal of a round-shaped wall of the epididymal tubule to create a “window” through which semen can pass freely. Afterward, the vas deferens lumen is sutured symmetrically from the inside to the outside, and the suture penetrates through the full thickness of the vas deferens wall. The suture is knotted, and the epididymal tubules are intussuscepted into the lumen of the vas deferens. Our results showed that in the bilateral surgery, the postoperative patency rate was 88.89% (40/45), the pregnancy rate was 28.89% (13/45), and the postoperative recurrence rate was 6.7% (3/45). As for the unilateral surgery, the potency rate was 68.42% (13/19), the pregnancy rate was 21.05% (4/13), and the postoperative recurrence rate of obstruction was 7.69% (1/13). The potency rate and natural conception rate of the fenestrated vasoepididymostomy in this study are comparable with previous reports [23‒26].

Compared with the conventional transversal and longitudinal two-suture anastomosis, the fenestrated anastomosis has the following advantages: first, in the longitudinal two-needle anastomosis, it is difficult to control the strength to make the longitudinal incision of the epididymal tubules, resulting in residual epididymal tubule outer membrane at the incision and hindering the smooth flow of the anastomosis [24]. The fenestrated anastomosis method can avoid the residual epididymal tubule outer membrane, making better patency in the anastomosis. Second, the “round window” can obtain a larger cross-sectional area than the anastomosis of the longitudinal or transverse incision and better patency. Third, the round lumen of the vas deferens is more matched with the round anastomosis of the epididymal tubule. Fourth, the suture penetrates through the full thickness of the vas deferens wall, making the epididymal tubule wall intussuscepted deeply into the lumen of the vas deferens, effectively preventing leakage and reducing the occurrence of semen granuloma. Fifth, in the longitudinal two-suture anastomosis, two parallel stitches are sutured on the epididymal tubule, and then an incision is made between the two sutures, making a limited surgical space. The diameter of the needle is 70 μm [16], and the width of two parallel needles is 140 μm, equivalent to the diameter of some epididymal tubules. Therefore, it inevitably requires selecting a thicker epididymal tubule for longitudinal two-suture anastomosis. Our fenestrated incision is transversally sutured; thereby, thin epididymal tubules can also be used. In addition, in the longitudinal two-suture anastomosis, premature leakage of semen is concerned as it disturbs the surgical field exposure [24]. On the contrary, in the fenestration technique, the outflow of semen makes it easier to see the edge of the window and facilitates needle insertion and suture.

There are still some limitations to this study. First, this study was limited by its retrospective nature. Also, the sample size of this study was small, especially for the patients receiving unilateral surgery. Furthermore, this study is not compared with the reference technique of vasoepididymostomy by intussusception with two sutures with a longitudinal incision without fenestration. In the future, a comparative study is necessary to demonstrate the superiority of this new technique compared to the reference technique.

In summary, our fenestrated transversal two-suture microsurgical intussusception vasoepididymostomy can achieve a good patency rate in OA patients and did not increase the difficulty and duration of the operation, which is worthy of clinical promotion for the treatment of epididymal OA.

This study was approved by the Institutional Review Board of Shenzhen People’s Hospital (No. LL-KY-2021641). Written informed consent was waived by the IRB due to the retrospective nature of this study.

The authors declare that they have no competing interests.

The study was supported by the Medical Scientific Research Foundation of Guangdong Province, China (B2020197) and the Research Projects of the Shenzhen Health System in 2017 (SZLY2017021).

Zengqin Liu, Bin Wang, and Zheng Ding designed the research study, analyzed the data, and wrote the manuscript. Hongtao Jiang, Qian Yuan, and Kefeng Xiao performed the research and collected the samples. Zheng Ding mainly revised the manuscript. All authors approved the final version of the article, including the authorship list.

All data generated or analyzed during this study are included in this article. Further inquiries can be directed to the corresponding author.