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Ann Surg. Apr 2005; 241(4): 553–558.
PMCID: PMC1357057

Herniorrhaphy With Polypropylene Mesh Causing Inguinal Vasal Obstruction

A Preventable Cause of Obstructive Azoospermia

Abstract

Objective:

To report a multiinstitutional experience of men presenting with infertility secondary to inguinal hernia repair using polypropylene mesh.

Summary Background Data:

An estimated 80% of inguinal hernia operations involve placement of a knitted polypropylene mesh to form a “tension-free” herniorrhaphy. The prosthetic mesh induces a chronic foreign-body fibroblastic response creating scar tissue that imparts strength to the floor and leads to fewer recurrences. However, little is known about the long-term effects of the polypropylene mesh on the vas deferens, especially with regard to fertility.

Methods:

Eight institutions in the United States reported a total of 14 cases of azoospermia secondary to inguinal vasal obstruction related to previous polypropylene mesh herniorrhaphy. Patient characteristics and operative findings were forwarded to 1 center for tabulation of data.

Results:

Mean patient age was 35.5 years with an average duration of infertility of 1.8 years. Mean number of years between urologic evaluation and herniorrhaphy was 6.3 years. Types of inguinal hernia repair previously performed were: open (10), laparoscopic (2), or both (2). Nine patients had bilateral obstruction and 5 patients had unilateral obstruction with contralateral testicular atrophy or epididymal obstruction. Surgical exploration revealed a dense fibroblastic response encompassing the polypropylene mesh with either trapped or obliterated vas in all patients. Surgical reconstruction was performed in 8 of 14 men (57%).

Conclusion:

Reconstruction to restore fertility can be difficult secondary to fibrotic reaction. Before undergoing polypropylene mesh herniorrhaphy, men, especially of young reproductive age or with a solitary testicle, need to be carefully advised of potential obstruction and compromise to future fertility.

Inguinal vasal obstruction (IVO) is an uncommon and potentially unrecognized cause of azoospermia in the male infertility patient. Consequently, the true incidence of vasal obstruction is unknown. Known causes of IVO usually are related to inguinal herniorrhaphy and may result from iatrogenic vasal ligation or injury, vascular compromise, or extrinsic compression. Recently, we have identified a group of patients with IVO associated with polypropylene mesh used in inguinal herniorrhaphy.

Inguinal herniorrhaphy is the operation most commonly performed by general surgeons with approximately 750,000 performed annually in the United States.1 An estimated 80% of these hernia operations involve placement of a knitted polypropylene monofilament mesh prosthesis to patch the defect in the floor of the inguinal canal.2 A “tension-free” repair is created and the spermatic cord is carefully placed on top of the mesh before closing.3 Subsequently, the prosthetic mesh induces an acute inflammatory reaction followed by a chronic foreign-body fibroblastic response that creates scar tissue and imparts strength to the floor.4–7 Clinically, open hernia repairs using the tension-free technique with polypropylene mesh have been shown to result in fewer recurrences than repairs using nonmesh methods.8 Laparoscopic hernia repairs using mesh apparently provide reports similar to those of open repairs but long-term data have not been reported.9

Regardless of surgical technique, little clinical information is available regarding the long-term effects of the polypropylene mesh on the vas deferens and other structures within the spermatic cord. One possible reason is that most men undergoing hernia repairs tend to be older and not concerned about maintaining their reproductive potential.7 However, with its widespread acceptance and ease of placement, polypropylene mesh repair is being offered increasingly to younger patients whose fertility status may well be an issue in the future. Although the estimated incidence of injury to the vas deferens is 0.3% in adult hernia repairs,10 only 1 case has been reported in the literature attributing secondary infertility to hernia repair with mesh.11 We report on a multiinstitutional experience of inguinal vasal obstruction related to tension-free herniorrhaphy using polypropylene mesh.

MATERIALS AND METHODS

Fourteen patients from 8 institutions throughout the United States were identified from 1998–2002, and their cases were reviewed. All patients underwent a comprehensive evaluation of infertility that included medical/surgical history, sexual history, female reproductive history, physical examination, hormonal testing, semen analyses, genetic testing, and ultrasonography. Attempts were made to obtain previous operative notes for all patients. The diagnosis of azoospermia was verified by at least 2 semen analyses showing absence of sperm in a seminal fluid pellet after centrifugation. Surgical exploration, testis biopsy, and vasography were performed in all patients, and intraoperative sperm cryopreservation was offered. When obstruction was seen at the level of the inguinal canal, exploration in the inguinal region was carried out and, when possible, vasal reconstruction attempted. When a contralateral atrophic testis with a patent vas deferens was present, a transscrotal crossed vasovasostomy was performed.

RESULTS

Fourteen men (age range, 28–42; mean, 35.5 years) were evaluated for male factor infertility of a mean duration of 1.8 years (range, 0.5–3 years). Testosterone, luteinizing hormone, and follicle-stimulating hormone levels were normal in all patients. All men had preoperative semen analyses confirming azoospermia (see Table 1).

Table thumbnail
TABLE 1. Clinical Data for Men With Infertility and Inguinal Vasal Obstruction Secondary to Inguinal Herniorrhaphy With Polypropylene Mesh

All 14 men had undergone hernia repairs with polypropylene mesh. An open hernia repair was performed in 10 men. Two men underwent laparoscopic hernia repairs only. Two men had a combination of laparoscopic and open hernia repairs at 2 separate operative times. Mean number of years between initial urologic evaluation and the most recent hernia repair with polypropylene mesh was 6.3 years (range, 2–12 years) (see Table 2).

Table thumbnail
TABLE 2. Preoperative Characteristics, Operative Findings, Reconstruction Performed, and Postoperative Outcomes for Infertile Men With Inguinal Vasal Obstruction Secondary to Use of Polypropylene Mesh

Three men had unilateral hernia repair only. Two of these 3 patients had solitary testicles secondary to previous orchiectomy (1 torsion, 1 cryptorchidism). The other patient had a contralateral epididymal obstruction discovered during an infertility evaluation. Of the 11 men who had undergone bilateral hernia repairs, 3 men had repairs performed on separate occasions.

Intraoperative vasograms showed obstruction at the level of the inguinal canal (see Fig. 1). Surgical exploration in the inguinal region at the previous hernia site revealed a dense fibroplastic response encompassing the polypropylene mesh with either trapped or obliterated vas deferens (see Fig. 2). A 2-layer microsurgical inguinal vasovasotomy was attempted in 5 patients. Crossover scrotal vasovasotomy was performed in an additional 2 patients. Reconstruction was not possible in 5 patients. One patient was able to undergo a contralateral left vasoepididymostomy but reconstruction was not possible on the side of the hernia repair.

figure 3FF1
FIGURE 1. Vasogram showing bilateral obstruction in the inguinal region at the site of the polypropylene mesh placement.
figure 3FF2
FIGURE 2. Intraoperative finding of obliterated vas deferens (**) within the polypropylene mesh (yellow arrows point to mesh fibers). Photograph courtesy of Harris M. Nagler, MD.

Follow-up semen analyses were available for 3 of 8 reconstructible patients. Average semen quality was 20 mil/mL with an average 20% motility (World Health Organization normal range: sperm density >20 mil/mL, motility >50%12). Of the 3 patients who had postoperative semen analyses, 1 achieved pregnancy with intrauterine insemination (IUI). An additional patient who did not provide a follow-up semen analysis achieved 2 natural pregnancies with his partner (see Table 2).

DISCUSSION

Inguinal vasal obstruction (IVO) related to inguinal herniorrhaphy is an uncommon and frequently unrecognized cause of azoospermia in the male infertility patient. The true incidence of IVO is unknown and likely to be underreported for several reasons. For a patient to present to an infertility clinic with azoospermia, either bilateral obstruction or unilateral obstruction with a poorly functioning contralateral testis would need to occur. Even if unilateral obstruction is present and results in decreased sperm concentration, a patient may not necessarily present with subfertility. In addition, because of good results with assisted reproductive technologies, some male factor patients are not even examined by a urologist and, therefore, exploration to determine causality is not performed. We report the first series of cases of inguinal vasal obstruction associated with polypropylene mesh.

Polypropylene monofilament knitted mesh was first introduced in 1963 by Usher13 as an improved version of the polyethylene plastic mesh that he had introduced in previous experimental and clinical papers.5,14–17 Most surgeons at that time reserved the use of the polypropylene mesh for large incisional, sliding, or recurrent inguinal direct hernias. Use was limited mainly because of concerns about increased wound infections, sinus tract formation, and prolonged healing, even though low infection and recurrence rates were reported when the mesh was used as the primary repair or as an onlay reinforcement in direct hernias.18,19

In 1989, Lichenstein introduced his pioneer concept of “tension-free” repair for all primary inguinal hernias using the polypropylene mesh.3 No recurrence or infection was seen in 1000 consecutive patients undergoing primary inguinal herniorrhaphy in 1- to 5-year follow up.3 Unlike surgeons who had reserved the synthetic mesh for “difficult” cases, Lichenstein advocated its routine use for all groin hernias.3 Subsequent studies demonstrated similarly low recurrence and infection rates using this technique.20,21 Because of its technical ease and associated minimal morbidity, tension-free herniorrhaphy with polypropylene mesh rather than techniques used by Bassini, McVay, and Shouldice has become the preferred method of treatment of inguinal hernia repairs regardless of patient age or severity of defect.

The success of the polypropylene mesh in inguinal hernia repairs has been attributed to its tensile strength. The scar tissue is created by the dense fibroblastic inflammatory reaction of the knitted monofilament incorporating the prosthetic mesh with the surrounding tissue. This intricate, interwoven prosthetic mesh is very thin and porous and unable to harbor infection yet is easily infiltrated with fibroblasts that impart permanent strength to the repair. This fibrotic reaction appears to strengthen the floor of the inguinal canal and decrease the incidence of recurrence. Because such a reaction is expected, the spermatic cord, which lies anterior to the mesh, could intuitively be affected in some fashion.

Uzzo and associates7 examined the local effects of polypropylene mesh on the spermatic cord in 12 male beagle dogs by performing a comparative histologic and clinical study of standard inguinal herniorrhaphy versus mesh inguinal herniorrhaphy. Although no difference in testis volume, temperature, and blood flow was observed when these control groups were compared, there was a significant decrease in cross-sectional vasal luminal diameters in both herniorrhaphy groups when compared with controls. Furthermore, a clearly marked foreign body reaction to the mesh was present in the tissue surrounding the spermatic cord. Although vasograms of all mesh-treated dogs showed patency at 1 year, it is possible that further vasal luminal narrowing leading to occlusion would have been seen in long-term follow up.

The incidence of IVO from any form of inguinal herniorrhaphy has not been clearly delineated. Published studies10,22 have suggested that the incidence of vasal injury ranges from 0.3% to 7.2%. IVO may occur for different reasons. It may result from direct iatrogenic injury caused by ligation, cauterization injury, or incision. However, it also may result from vascular compromise or extrinsic compression. Some of these injuries may be identified intraoperatively and repaired, but in many cases, delayed obstruction secondary to extrinsic compression or vascular compromise may remain unrecognized. Because invasive diagnostic studies such as vasography would be necessary to determine actual frequency of injuries and these studies are not always clinically appropriate, the true incidence of IVO will likely remain difficult to ascertain. Vasogram is the standard of care to identify whether obstruction is present in the inguinal area. An ideal approach to determine incidence would be to perform vasograms in autopsies of patients who had undergone inguinal herniorrhaphy.

Currently, there are no published data comparing the incidence of IVO with standard and with polypropylene mesh herniorrhaphy. Our review was limited to cases of IVO related to polypropylene mesh herniorrhaphy. We are unable to determine whether obstructive azoospermia in these cases is a direct result of effects of polypropylene mesh repair or of surgical misadventure. Although this report suggests that problems may occur, it is unclear whether polypropylene mesh will result in a higher or lower incidence of IVO than standard inguinal herniorrhaphy.

Because male infertility specialists are the physicians most likely to treat patients with IVO, careful preoperative discussion of possible mesh-related inguinal adhesions is necessary, especially when the urologist is faced with an azoospermic patient with either bilateral herniorrhaphies or unilateral herniorrhaphy and contralateral abnormalities consistent with either a nonfunctioning testis or obstruction. Because of the difficulty with reconstruction in these cases, sperm cryopreservation at the time of surgery is highly recommended. Success with cryopreserved sperm and in vitro fertilization and intracytoplasmic sperm injection (ICSI) is likely to be similar to pregnancy rates seen in other cases of obstructive azoospermia. Reconstruction should be directed toward a potential vasal crossover procedure if possible, but this requires a unique clinical situation. More commonly, preparation for a significant inguinal/retroperitoneal dissection should be discussed preoperatively with the patient. A recently introduced option is laparoscopic mobilization of the retroperitoneal vas deferens.23 Surgeons with these skills can provide valuable intraoperative consultation to minimize open inguinal and retroperitoneal dissection.

Although success can be achieved with reconstruction, attention should be focused on prevention given the potentially high costs for reconstruction and/or sperm retrieval with in vitro fertilization and ICSI. As noted, a severe desmoplastic reaction is to be expected when mesh is used. Some general surgeons will use a polypropylene patch to cover the floor of the inguinal canal, whereas others favor a polypropylene plug. Others will carve out a slot in the polypropylene patch to allow safe passage of the spermatic cord. However, mesh with a larger opening (approximately 1.5 cm in diameter) may be necessary to minimize contact between the spermatic cord and mesh. A round opening in the mesh may be better than a slit for passage of the spermatic cord. Placement of a mesh plug in direct contact with a bare vas deferens is not recommended and fat or muscle may be interposed for protection. Alternatively, mesh with a polytetrafluoroethylene surface (Bard; Spermatex, Murray Hill, NJ) could be used to minimize adhesions and tissue attachments between the spermatic cord and prosthesis. In addition, the spermatic cord should be handled carefully during dissection of the hernia sac to reduce the risk of exposing the vas deferens to the mesh. Although the majority of our patients underwent open herniorrhaphy, IVO occurred in patients undergoing laparoscopic repair, further demonstrating that both techniques are susceptible to vasal injury. We do not want to recommend major changes in surgery for inguinal herniorrhaphy. We merely want to caution the surgeon to consider protecting the vas deferens when mesh or standard herniorrhaphy is performed.

Therefore, patients of reproductive age need to be counseled preoperatively regarding the risks of vasal obstruction associated with inguinal herniorrhaphy. Admittedly, there is risk associated with both standard inguinal herniorrhaphy and inguinal herniorrhaphy with polypropylene mesh. However, specific risks of vasal injury with inguinal herniorrhaphy and their incidence associated with the use of polypropylene mesh are not known. When bilateral or unilateral hernias with impairment of the contralateral testis are present, patients should be counseled about the risk of vasal injury.

In conclusion, reconstruction to restore fertility is extremely difficult when vasal obstruction has occurred because of significant fibrotic reaction to polypropylene mesh. Cryopreservation of sperm is highly recommended at the time of reconstruction. Before standard herniorrhaphy or herniorrhaphy using mesh, young men need to be advised of the potential risk of vasal obstruction and possible compromise of their future fertility.

Footnotes

Reprints: Stanton C. Honig, MD, Urology Center, 60 Temple St., New Haven, CT 06510. E-mail: moc.liamg@ginoh.nats.

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