A Modified Vessel-Sparing Microsurgical Vasoepididymostomy

Summary

Here, we present a protocol to preserve the vasal vessels in microsurgical vasoepididymostomy. The surgical security is enhanced by preserving the vasal vessels using a retrograde-anterograde dissociation and fixing the vasal vessels.

Abstract

Microsurgical vasoepididymostomy (MVE) is the main surgical treatment for epididymal obstruction. The vasal vessels are ligated during MVE. However, preserving the vasal vessels during MVE might better simulate the normal physiological structure and be meaningful for patients who have undergone varicocelectomy. Nevertheless, preserving the vasal vessels might elevate the risk of increasing the tension of anastomosis, affecting the patency rate and leading to delayed postoperative bleeding. Therefore, we developed a novel vessel-sparing MVE to make it safer. Here is a summary of the improvements to the procedure. 1) The retrograde dissociation of the vasal vessels on the proximal testicular side was adopted as the main method, and the anterograde dissociation of the vasal vessels on the distal testicular side was adopted as a supplement to dissociate the vasal vessels to be preserved. This improvement ensures the blood supply to the vas deferens that will be used for anastomosis and also provides longer vasal vessels, which reduces the tension of anastomosis. 2) By fixing the vas deferens to be anastomosed and the broken end of the vas deferens, the free vasal vessels get fixed, which resolves the problem of transmission of vas tension to the vasal vessels and reduces the risk of vasal vessel hemorrhage. 3) Dissociation of the vas deferens after opening the tunica vaginalis increases the mobilization of the vas deferens, which also makes the new procedure easier to complete. The evaluation of the outcomes of this new procedure showed that no significant postoperative complications occurred in the patients, and the patency rate was no different from that of the conventional procedure. Therefore, this new, improved procedure can be considered safe, with satisfactory postoperative results.

Introduction

Epididymal obstruction is the most common cause of obstructive azoospermia. Microsurgical vasoepididymostomy (MVE) is the main surgical treatment for epididymal obstruction. Although various MVE techniques^1,2,3,4 have been described previously, a two-needle longitudinal intussusception vasoepididymostomy (LIVE) technique described by Chan et al.^5,6 has been recognized as the gold standard for achieving a superior patency rate⁷. The vasal vessels are typically ligated in LIVE. Ligation of the vasal vessels simplifies the procedure and reduces the tension of anastomosis, and a tension-free anastomosis is critical to achieving a successful outcome.

The vas artery primarily supplies the epididymis and vas deferens⁸. Whether preservation of the vas artery improves the postoperative patency rate remains unclear. However, preserving the vasal vessels during MVE might better simulate the normal physiological structure. Also, for patients who have undergone varicocelectomy, it may be meaningful to perform the vessel-sparing MVE, because the integrity of vasal vasculature plays a vital role in post-varicocelectomy blood supply and the venous return of the testis. A few studies^9,10,11 have attempted to preserve the vasal vessels during MVE and suggested that the procedure may have certain benefits. However, preserving the vasal vessels makes the operation of anastomosis more difficult and increases the tension of anastomosis. In addition, the tension of the vas deferens may be transmitted to the vasal vessels and cause postoperative bleeding of the little branches of the vessels. Besides, the existing vessel-sparing procedure may affect the blood supply of the vas deferens. Therefore, we improved the surgical technique of vessel-sparing MVE to make it safer. We called this new procedure microsurgical vasoepididymostomy by preserving the vasal vessels using a retrograde-anterograde dissociation.

Protocol

This study was approved by the Ethics Committee of Northwest Women's and Children's Hospital (No. 2021002).

1. Preparations

1. Place the patient supine on the operating table and perform anesthesia as per the anesthetist's recommendations.
2. Insert a 16Fr Foley catheter around the incision site after the field is disinfected and covered with surgical drapes.

2. Modified vessel-sparing LIVE

1. Create a 3 cm vertical incision in the middle of the scrotum and deliver the testis from the incision.
2. Open the tunica vaginalis. Carefully dissociate the vas deferens and adjacent vessels. The dissociated length is ~5 cm (Figure 1).
3. Place an operating microscope and ready the micro instruments: a micro needle holder, micro scissors, and micro forceps. Execute the following steps using the operating microscope.
4. Create a buttonhole of a diameter of 5 mm at the tunica of cauda epididymis using micro scissors. Identify a dilated epididymal tubule and carefully dissociate it using micro forceps. After that, keep it for anastomosis.
5. Place two needles of double-armed 11-0 microsutures longitudinally in the selected epididymal tubule, and open the epididymal tubule longitudinally between the two needles using a 15° ophthalmic knife. Ensure that the opening length does not exceed the length between the entry point and the exit point of the suture on the epididymal tubule (Figure 2).
6. Sample some epididymal fluid flowing from the incision in the tubule with a glass slide and hand it to an examiner to check for sperm. Gently pull out two needles in the epididymal tubule separately if sperm are found.
7. Make a puncture in the gap between the vas deferens and adjacent vessels using deferens separating forceps. The puncturing site is approximately 1 cm away from the junction of the cauda epididymis and the vas deferens. Completely transect the vas deferens above the deferens separating forceps with a knife, and preserve the vasal vessels below the deferens separating forceps (Figure 3).
8. Cannulate the 24-G angiocatheter sheath into the vas deferens lumen on the distal testicular side, followed by a bolus injection of diluted methylene blue. Observe the color of the urine. Blue staining of the urine indicates distal patency.
9. Dissociate the vas deferens on the proximal testicular side using micro scissors to separate it from the vasal vessels. Ensure that the dissociation is executed along the vas deferens side to avoid damage to the vasal vessels. The dissociated length is ~2-3 cm. Then, remove the dissociated vas deferens and ligate the broken end of the vas deferens. During the dissociation, stop the bleeding using bipolar electrocoagulation or by ligating some small branch vessels using a 5-0 silk thread. This operation is called retrograde dissociation (Figure 4 and Figure 5).
10. Carefully separate the vas deferens on the distal testicular side from the vasal vessels using deferens separating forceps combined with micro scissors. The dissociated length is ~0.5 cm. Separate the vas deferens and the vasal vessels without damaging the vas deferens or the vasal vessels. This operation is called anterograde dissociation (Figure 4 and Figure 6).
11. Fix the vas deferens to be anastomosed with the tunica vaginalis using 8-0 microsutures at the included angle between the vas deferens and adjacent vessels. After fixation, ensure that the lumen of the vas deferens reaches the anastomosis site with no significant tension. This is regarded as the first-stage tension reduction.
12. Fix the muscularis edge of the vas deferens and epididymis tunica using 3-4 interrupted 8-0 microsutures. This is regarded as the second-stage tension reduction.
13. Pass the four needles of 11-0 microsutures in the epididymal tubule through four points (Figure 7) on the cutting surface of the vas deferens in an inside-out fashion. Then, perform the intussusception of the epididymal tubule into the vas deferens⁸.
14. Suture the muscularis edge of the vas deferens and the epididymal tunica using 10-12 interrupted sutures of 8-0 microsutures.
15. Fix the broken end of the vas deferens on the tunica vaginalis using 3-4 interrupted sutures of 8-0 microsutures (Figure 4 and Figure 8). Ensure that the free vasal vessels are fixed and cannot move. This operation is called fixation of the vasal vessels.
16. Check whether there is tension in the vas deferens and whether there is tension and bleeding in the preserved vasal vessels. Then, suture each layer of tissue sequentially and terminate the operation.

3. Postoperative management

1. Avoid sexual intercourse for 1 month after surgery.
2. Wear a scrotal supporter or tight underpants for 1 week after surgery, and avoid standing or walking for a long time.
3. Take antibiotics for 1 week to prevent infection.

Representative Results

A total of 51 patients who underwent vasoepididymostomy at our center between February 2018 and November 2020 were retrospectively analyzed. Considering the anastomotic tension, the modified procedure was performed only in patients with obstruction at the corpus or caudal epididymal, and these patients were included in the current study. Semen examination was performed 1.5 months after the surgery, and the patients were followed up for more than 1 year. Relevant data of patients with the results of at least one semen test during the postoperative follow-up were included in the current study. Sperm concentrations >1 x 10⁴ sperm/mL was defined as successful patency. Postoperative complications, especially scrotal hematoma within 1 week after surgery, pain or discomfort in the scrotal area after exercise 1 month after surgery, and testicular atrophy after surgery, were recorded. The patency rate was also evaluated.

Among the 51 cases, 22 were treated using the new method, and spermatozoa were detected in the postoperative semen in 19 cases. The postoperative patency rate was 86.4%. Among the 29 cases who underwent the conventional procedure, spermatozoa were detected in 25 cases, and the postoperative patency rate was 86.2%. There was no statistically significant difference in the postoperative patency rate between the two groups (P = 0.997, using the Chi-square test). For the two groups, the recovery was good, and there was no postoperative scrotal hematoma, scrotal pain, or testicular atrophy. Considering there were a few patients who did not complete the follow-up, the current study did not include an evaluation of the postoperative natural pregnancy rate (Table 1).

Figure 1: Dissociation of the vas deferens and the vasal vessels. Open the tunica vaginalis. Carefully dissociate the vas deferens and adjacent vessels. The dissociated length is ~5 cm. Please click here to view a larger version of this figure.

Figure 2: Preparation of the epididymal tubule. Place two needles of double-armed 11-0 microsutures longitudinally in the selected epididymal tubule, and open the epididymal tubule longitudinally between the two needles using a 15° ophthalmic knife. Please click here to view a larger version of this figure.

Figure 3: Separation of the vas deferens from the vasal vessels. Make a puncture in the gap between the vas deferens and adjacent vessels using a deferens separating forceps. Please click here to view a larger version of this figure.

Figure 4: Schematic diagram of the modified procedure. 1) The retrograde dissociation of the vasal vessels on the proximal testicular side was adopted as the main method, and the anterograde dissociation of the vasal vessels on the distal testicular side was adopted as a supplement to dissociate the vasal vessels to be preserved. 2) By fixing the vas deferens to be anastomosed and the broken end of the vas deferens, the free vasal vessels get fixed. Please click here to view a larger version of this figure.

Figure 5: Retrograde dissociation. Separate the vas deferens on the proximal testicular side from the vasal vessels. Please click here to view a larger version of this figure.

Figure 6: Anterograde dissociation. Separate the vas deferens on the distal testicular side from the vasal vessels. Please click here to view a larger version of this figure.

Figure 7: Schematic diagram of LIVE. Pass the four needles of 11-0 microsutures in the epididymal tubule through four points (a_1-2, b_1-2) on the cutting surface of the vas deferens in an inside-out fashion. Then, perform the intussusception of the epididymal tubule into the vas deferens. Please click here to view a larger version of this figure.

Figure 8: The fixation of the vasal vessels. Fix the vas deferens to be anastomosed and the broken end of the vas deferens on the tunica vaginalis, respectively, to make sure that the free vasal vessels cannot move. Please click here to view a larger version of this figure.

	Modified procedure (n = 22)	Conventional procedure (n = 29)	P-value
Age(year)	30.5 ± 4.8	30.8 ± 5.5	0.825
Patency rate (%)	86.4 (19/22)	86.2 (25/29)	1.000
Postoperative scrotal hematoma	0	0	/
Postoperative scrotal pain	0	0	/
Postoperative testicular atrophy	0	0	/

Table 1: Comparison of postoperative results between the modified procedure and the conventional procedure. There was no statistically significant difference in the postoperative patency rate between the two groups (P = 0.997). There was no postoperative scrotal hematoma, scrotal pain, or testicular atrophy in the two groups.

Discussion

Vessel-sparing microsurgical vasoepididymostomy might have some clinical significance. Although it is not confirmed that this approach can improve the patency rate, it might better simulate the normal physiological structure and has certain significance for patients who have undergone varicocelectomy. This can be attributed to the fact that preservation of the deferential artery and vas deferens vein have positive effects on the blood supply to the testis after varicocelectomy and the venous return of the testis, respectively. However, there is a risk of vasal vessel preservation, which may increase the tension of anastomosis and the risk of postoperative bleeding and affect the blood supply to the vas deferens due to the separation of the artery from the vas deferens. Therefore, we improved the surgical technique of vessel-sparing MVE to make it safer.

We redesigned the vessel-sparing vasoepididymostomy procedure using retrograde-anterograde dissociation of the vasal vessels and innovatively adopted the method of fixing the vasal vessels, which increased the safety of the surgery and reduced the tension of the anastomosis. The specific surgical improvements were as follows. Firstly, the vasal vessels to be preserved were dissociated using retrograde dissociation of the vasal vessels on the proximal testicular side as the main method and the anterograde dissociation of the vasal vessels on the distal testicular side as a supplement. This improvement ensured the blood supply to the vas deferens that was used for anastomosis and also provided longer vasal vessels, which reduced the tension of anastomosis. Secondly, the vas deferens to be anastomosed and the broken end of the vas deferens were fixed on the tunica vaginalis, respectively, to make sure that the free vasal vessels cannot move. The transmission of vas deferens tension to the vasal vessels was avoided, and the risk of vasal vessel hemorrhage was reduced. Thirdly, the vas deferens was dissociated after opening the tunica vaginalis. This increased the mobilization of the vas deferens so that, theoretically, some obstructions close to the caput epididymal could also be resolved using our modified procedure.

The dissociation and protection of the vasal vessels are key steps for the success of this novel procedure. Particularly, the vasal vessels may be occasionally damaged during dissociation of the vas deferens on the proximal testicular side and the vasal vessels, resulting in decreased efficacy of the novel procedure. Hence, the micromanipulation skills of the surgeon should be continuously improved. Besides, as the vas deferens on the proximal testicular side is the last tissue to be removed, the dissociation should be executed at the vas deferens side during the separation of the vas deferens on the proximal testicular side and the vasal vessels to avoid damage to the vasal vessels. This would facilitate the successful protection of the vasal vessels. Additionally, the vas deferens on the proximal testicular side should be fixed on the tunica vaginalis instead of the epididymis to avoid epididymal obstruction. In our study, an inspection of the vasal fluid was not part of the regular examination for these patients, since all cases were epididymal obstruction but not obstruction of the vas deferens. For patients prepared for vasectomy reversal, an inspection of the vasal fluid would be recommended to explore the possibility of vasovasostomy; however, vasectomy is seldom conducted in China today.

No significant postoperative complications have occurred in the patients who received this modified procedure until the submission of this manuscript, and there was no significant difference in the postoperative patency rate between the modified and conventional procedures. Therefore, the modified procedure is safe, with a satisfactory postoperative patency effect. It may not only preserve the vasal vessels and simulate the normal physiological structure but also achieve a satisfactory patency rate. In addition, there was no significant difference in total motile sperm count (TMSC) between the two groups (P = 0.869). However, there is a possibility that an increased sample size may provide different results.

The new procedure may prolong the surgical time and exhibit increased difficulty. In order to ensure the operation quality, the criteria for selecting the procedure are that the new procedure will be performed if there is only one operation on the day; otherwise, the traditional procedure will be performed if there are two or more operations on the same day or the patients refuse to try the new procedure. Moreover, although theoretically, the obstruction of the caput epididymal can be resolved using the modified procedure; however, tension may be generated as the anastomotic site moves toward the caput epididymal owing to the limited dissociated lengths of the vasal vessels, so we still recommend the modified procedure for only those patients with the obstruction of the corpus or caudal epididymal.

In summary, the modified procedure, microsurgical vasoepididymostomy by preserving the vasal vessels using retrograde-anterograde dissociation, is safe and effective for vasoepididymostomy. This modified procedure can complete vasoepididymostomy without destroying the normal physiological structure. It is a safe procedure and may enhance blood supply and venous return to the testis. Hence, we recommend it for patients with obstruction of the corpus or caudal epididymal. Future studies shall further clarify the advantages of the proposed procedure using a randomized control trial.

Materials

Name	Company	Catalog Number	Comments
11-0 microsutures	Ningbo Medical Needle Co.,Ltd	211115	Double-armed microsurgical nylon suture length: 5 cm
15° ophthalmic knife	pearsalls limited	72-1501	open the epididymal tubule
2-0 silk braided non-absorbable suture	Coated	1604-51	Ligation of the vas deferens
24-Gangiocatheter sheath	Melsungen AG	4253523-03	injection
5-0 silk braided non-absorbable suture	Johnson & Johnson	SA82G	Ligation of blood vessels
8-0 microsutures	Johnson & Johnson	W2908	Single-armed microsurgical nylon suture length: 13 cm
Deferens separating forceps	Shanghai Medical Instrument Co., Ltd	JCZ210	Separation of vas deferens
Micro scissors	Shanghai Medical Instrument Co., Ltd	WA1040	Microsurgical operation
Microforceps	Shanghai Medical Instrument Co., Ltd	WA3090	Microsurgical operation
Microneedle holder	Shanghai Medical Instrument Co., Ltd	WA2040	Microsurgical operation
Operating microscope	Leica Microsystems(Sch weiz) AG	M525MS3	Microsurgical operation