Hydrocele

Embryological basis

The processus vaginalis begins as a protrusion of the peritoneum around the 12th week of gestation and extends into the scrotum in boys. The scrotal part of the processus vaginalis mostly surrounds the testis to form the tunica vaginalis, although the posterior aspect of the testis that is attached to the epididymis is not covered by the tunica. Following testicular descent, the proximal aspect of the processus undergoes obliteration.

The corresponding s​tructure in females extends in the canal of Nuck and is attached to the ipsilateral labia.[3] (See the image below.)

Young girl with groin bulge, which, at surgery, was a hydrocele of along the canal of Nuck.

Hydroceles have been classified as primary or secondary. Primary hydroceles are those of congenital origin and may be further divided into communicating or non-communicating (ie, with or without patency between peritoneum and scrotum). Secondary hydroceles are caused by conditions such as inflammation, infection, previous surgeries, or testicular torsion.

The presence of a hydrocele alone has minimal clinical significance. Hydroceles do not have an effect on later fertility. The primary concern is to rule out associated malignancy, infection, or other treatable conditions. Symptoms, primarily size and discomfort, are typically the reasons that patients seek medical attention.  

A patent processus vaginalis is found in 80-90% of term male infants at birth. This frequency rate steadily decreases until age 2 years, at which point it appears to plateau at approximately 25-40%. Despite this, hydroceles are only observed in 1-5% of children.[4] Transforming growth factor beta1 (TGFβ1), which is a potent fibrogenic agent, may stimulate fibrosis and closure of the processus vaginalis.[5] Certain conditions, such as breech presentation, prematurity,[4] gestational progestin use, and low birth weight, have been associated with an increased risk of hydroceles.

In a Swedish study, the annual incidence of hydroceles in patients age 18 years and older who presented to specialized healthcare was 60 per 100,000 men. However, surgical management of hydrocele or spermatocele was required in only 17 per 100,000 men.[6]

Worldwide, the most common cause of hydrocele in the adult population is filariasis, a parasitic infestation caused by Wuchereria bancrofti (see Filarial Hydrocele). Filariasis affects more than 90 million people in more than 52 countries.[7] However, this condition is virtually nonexistent in the United States.

The World Health Organization (WHO) considers lymphatic filariasis (LF) to be endemic in 72 countries, including Brazil, the Dominican Republic, Guyana, and Haiti in the Americas. Rates of hydrocele in endemic areas can reach 25% in males with LF.[8]

In children, most hydroceles are congenital and of the communicating type, in which patency of the processus vaginalis allows peritoneal fluid to flow into the scrotum, particularly during Valsalva maneuvers. With noncommunicating hydroceles, in both children and adults, fluid accumulates because of altered balance between fluid production and absorption within the tunica. Noncommunicating hydroceles can also be congenital, or they may result from conditions such as inflammation, infection, previous surgeries, or testicular torsion.[3]

Following laparoscopic or transplant surgery in males, inadequate aspiration of irrigation fluid may cause hydroceles in patients with a patent processus vaginalis or a small hernia. Careful aspiration of fluid at the end of laparoscopic procedures helps prevent this complication.

A few studies have attempted to show a link between certain molecular derangements and an increased incidence of patent processus vaginales (and therefore hydroceles and indirect hernias). Two such examples include increases in maternal estrogen concentrations during pregnancy and abnormalities in the calcitonin gene–related peptide (CGRP) released by the genitofemoral nerve.[9]

Mesotheliomas of the tunica vaginalis are rare, but should be considered in patients with a history of asbestos exposure who have a complex hydrocele with hypervascular parietal vegetations.[10, 11, 12]

Filariasis, a parasitic infestation caused by Wuchereria bancrofti, accounts for most causes of hydroceles in adults worldwide, affecting more than 90 million people in more than 52 countries.[7] However, this condition is virtually nonexistent in the United States, where iatrogenic causes of hydroceles predominate.

The pathophysiology of hydroceles involves an imbalance between scrotal fluid production and absorption. This imbalance can be divided further into exogenous fluid sources or intrinsic fluid production.

A commonly utilized classification system classifies hydroceles into primary, secondary communicating, secondary non-communicating, microbe-induced, inflammatory, iatrogenic, trauma induced, tumor induced, canal of Nuck or giant.[13] This classification is based on the possible etiology but can be confusing to utilize. Hoang et al have proposed an updated classification system that divides primary hydrocele into the following 7 types, on the basis of findings at surgery[14] :

1. Peritesticular or vaginal hydrocele; if fluid is excessive, leads to abdominoscrotal hydrocele
2. Noncommunicating hydrocele without hernia
3. Noncommunicating hydrocele with hernia
4. Communicating hydrocele without hernia
5. Communicating hydrocele with hernia
6. Noncommunicating hydrocele of the spermatic cord and the scrotum; if fluid is excessive, leads to abdominoscrotal hydrocele
7. Encysted spermatic cord hydrocele, or encysted hydrocele of the canal of Nuck

In general, most urologists limit classification to communicating or non-communicating, as this has a direct impact on the surgical management. Abdominoscrotal hydroceles can be considered in a separate category, and most likely are similar to canal of Nuck hydroceles.

Communicating hydroceles

Communicating hydroceles are typically noted in children and are associated with a persistent patent processus vaginalis (PPV). In a prospective study of 526 infants younger than 4 months who were undergoing laparoscopic pyloromyotomy, PPV was noted in 54%; however, when followed for > 1 year, only 1.2% of those patients required surgical management for the PPV.[15]

Management tends to be expectant during the first year of life. For PPV that persists beyond the first year of life, or causes symptoms, surgical care may be recommended.

Communicating hydroceles may also be due to iatrogenic causes, such as migration of a ventriculoperitoneal shunt or extension of peritoneal fluid from intraperitoneal dialysis.  

Open or laparoscopic techniques for treatment of hydrocele have similar outcomes. There is a 15% incidence of PPV in the contralateral inguinal region, when evaluated at the time of surgery.[16] Management of communicating hydroceles requires approaching the PPV in the inguinal canal rather than through the scrotum.

Noncommunicating hydroceles

Noncommunicating hydroceles may result from increased fluid production or impaired fluid absorption. Multiple causes have been cited for the development of noncommunicating hydroceles. This is typically the type of hydrocele noted in patients with filariasis. Noncommunicating hydroceles may also be secondary to torsion of the appendix testis, tumors, or inflammatory or infectious conditions, including syphilis, tuberculosis, and epididymitis.

Other potential iatrogenic causes include varicocele surgery that leads to disruption of the lymphatic system. In patients with a penile prosthesis, secondary hydrocele due to migration of the pump has been reported.

Abdominoscrotal hydroceles

This is the most uncommon type of hydrocele. These have an inguinoscrotal component, with a second larger or small intra-abdominal component. The intra-abdominal component can be so large that it can cause renal obstruction.[17]

Hydrocele that extended retrograde into the abdominal compartment.

Hydroceles typically manifest as a soft nontender fullness within the hemiscrotum that occur over a variable period of time. If communicating, the hydrocele will increase in size with increased intra-abdominal pressure and decrease in size when the patient is lying supine.[4] The testis is generally palpable along the posterior aspect of the fluid collection. When the scrotum is investigated with a focused beam of light, the scrotum transilluminates, revealing a homogeneous glow without internal shadows.

Hydroceles of the canal of Nuck in female patients typically present as soft, nontender inguinal or labial swelling. See the image below. Like hemiscrotal hydroceles, labial hydroceles transilluminate readily.[18, 19]

Young girl with groin bulge, which, at surgery, was a hydrocele of along the canal of Nuck.

Indications for intervention in hydroceles include the following:

• Inability to distinguish from an inguinal hernia
• Failure of the hydrocele to resolve spontaneously after an appropriate interval of observation
• Inability to clearly examine testis
• Association of hydroceles with suggestive pathology (eg, torsion, tumor)
• Pain or discomfort
• Male infertility
• Cosmesis

The developmental anatomy of the inguinal canal is responsible for the genesis of pediatric communicating hydroceles. As the testis descends from the posterolateral genitourinary ridge at the beginning of the third trimester of fetal gestation, a saclike extension of peritoneum descends in concert with the testis. As descent progresses, the sac envelops the testis and epididymis. The result is a serosal-lined tubular communication between the abdomen and the tunica vaginalis of the scrotum.

The peritoneum-derived serosal communication is the processus vaginalis, and the serosa of the hemiscrotum becomes the tunica vaginalis. At term, or within the first 1-2 years of life, the processus vaginalis of the spermatic cords fuse, thereby obliterating the communication between the abdomen and the scrotum. The processus fuses distally as far as the lower epididymal pole and anteriorly to the upper epididymal pole. Failure of complete fusion may result in communicating hydroceles, indirect inguinal hernias, and the bell-clapper deformity of abnormal testicular fixation in the scrotum.[20]

No true absolute contraindications exist for repair of hydroceles. However, given the minimal clinical consequence of the hydrocele itself, any condition that classifies patients as poor surgical or anesthetic risk may be considered a relative contraindication to surgical repair.

Additionally, while a slight majority of pediatric surgeons across North America would repair any communicating hydrocele (somewhat irrespective of age) if it were clearly communicating, waiting until the child is 1-2 years old is certainly reasonable. Finally, small atrophic testes, or solitary testes, should be approached with great caution to minimize the risk of anorchia.

In a review of data from 355 pediatric patients with hydroceles, Acer-Demir et al reported high rates of spontaneous resolution, with virtually all children older than 1 year of age who did not undergo surgery showing spontaneous resolution within 1 year.[21] These authors recommend monitoring congenital hydroceles until at least 1 year and preferably 2 years of age, unless strong evidence of hydrocele-induced testicular damage arises, and recommend monitoring noncongenital hydroceles for at least 6 months and preferably 1 year if the patient has no associated pathology indicating the need for earlier surgery.[21]

Simple hydroceles are diagnosed on clinical grounds. Clinical findings that should raise the suggestion of a different diagnosis or some additional underlying pathology include the following:

• Inability to clearly delineate or palpate the testicular structure
• Local tenderness, fever, or any gastrointestinal symptoms (eg, vomiting, constipation, diarrhea)
• Internal shadows on transillumination

Scrotal ultrasonography is the next logical step in such cases.

Few laboratory tests, if any, are warranted specifically for simple hydroceles, communicating or noncommunicating. Concomitant medical conditions may be indications for preoperative laboratory studies. Laboratory studies may be indicated to exclude other surgical or medical conditions that may be in the differential diagnosis.

Inguinal hernia

While laboratory studies are not warranted in routine inguinal herniorrhaphy, a possible incarcerated inguinal hernia may be difficult to distinguish from a hydrocele.

Findings that may favor urgent exploration in this setting include the following:

• Failure to clearly transilluminate
• Palpable bowel at the internal ring during the rectal examination
• An elevated white blood cell count

Testicular tumor

Approximately 10% of patients with testicular teratomas may present with a cystic mass that may transilluminate during the physical examination. Similarly, adults with testicular tumors may present with new-onset scrotal swelling. If this diagnosis is considered, measuring serum alpha-fetoprotein and human chorionic gonadotropin (hCG) levels is indicated to exclude malignant teratomas or other germ cell tumors.

Epididymitis/orchitis

Occasionally, a reactive hydrocele occurs in association with underlying testicular infection. Urinalysis and urine culture may be beneficial. Although urinalysis and/or culture results are positive in only 30% of such cases, a positive culture result may be useful in guiding antimicrobial treatment. Symptoms are treated with nonsteroidal anti-inflammatory drugs (NSAIDs) and scrotal elevation.

The radiographic evaluation of hydroceles is controversial. Communicating hydroceles in patients (infants in particular) with a classic presentation and palpable testicle do not require radiographic studies. However, findings from radiographic or ultrasonographic studies can help evaluate for other underlying processes, such as a tumor or torsion, and can be useful in the setting of a non-communicating hydrocele or inability to palpate the testicle, acute onset of swelling/pain, or other atypical findings on presentation or examination.

Ultrasonography

Ultrasonography provides excellent detail of the testicular parenchyma. Spermatoceles can be clearly distinguished from hydroceles on sonograms. If a testicular tumor is a diagnostic consideration, ultrasonography is an excellent screening study.

In addition, testicular atrophy suggesting chronic torsion and a reactive hydrocele can be seen on sonograms. Failure to clearly delineate testicular anatomy with palpation indicates the need for further diagnostic imaging such as ultrasonography.

In female patients, hydrocele along the canal of Nuck typically appears on ultrasonography as a fluid-containing lesion in the inguinal area that is well defined, thin walled, and sausage-shaped, with or without internal septations.[22]

Duplex ultrasonography

Duplex studies may provide substantial information regarding testicular blood flow when a hydrocele may be associated with chronic torsion.

Additionally, epididymitis associated with a reactive hydrocele can be distinguished based on findings from duplex scanning, as evidenced by increased epididymal flow.

Finally, duplex studies may help identify Valsalva-augmented regurgitant flow in patients with varicoceles.

Plain abdominal radiography

Plain radiography may be useful for distinguishing an acute hydrocele from an incarcerated hernia. Gas overlying the groin may indicate an incarcerated hernia.

Computed tomography

Imaging studies for abdominoscrotal hydroceles typically include computed tomography (CT) to determine the true extent of the intra-abdominal component.

If a hernia is identified along with the hydrocele, the sac may be removed following high ligation and sent for pathologic analysis. In this case, the histology findings are consistent with peritoneal lining.[23]

In pediatric patients, communicating hydroceles are surgically managed if they persist beyond the first year or two of life. Additionally, large noncommunicating hydroceles may also warrant surgical management. 

Abdominoscrotal hydroceles (and canal of Nuck hydroceles) require an inguinal approach so that the abdominal extent can be managed. Surgical excision has been considered appropriate for these entities, although excision of the intra-abdominal component can be quite challenging. A combined laparoscopic-inguinal approach may allow more complete determination of resection.[24]

Asymptomatic adults with isolated noncommunicating hydroceles can be observed indefinitely or until they become symptomatic, as complications such as infection or testicular compromise are exceedingly rare. However, if the diagnosis is in question or underlying pathology cannot be excluded, operative exploration is warranted.

Surgical therapy can be divided into three approaches: inguinal, scrotal, and sclerotherapy. For more information on surgery in children, see Pediatric Hydrocele and Hernia Surgery.

Inguinal

The inguinal approach, with ligation of the processus vaginalis high within the internal inguinal ring, is the procedure of choice for pediatric hydroceles (typically, communicating). If a testicular tumor is identified on testicular ultrasonography, an inguinal approach with high control/ligation of the cord structures is mandated.

In a study by Saka et al, 69 patients with hydrocele underwent either laparoscopic percutaneous extraperitoneal closure (40 patients) or open repair (29 patients), and the safety and efficacy of the two approaches were compared. There were no significant differences in length of operation, anesthesia, or complications for the two procedures; and no recurrences were observed for either procedure.[25]

In addition, the authors reported on the features of the internal inguinal ring (IIR) found in cases of hydrocele and in cases of inguinal hernia treated during the study period. In the cases of hydrocele, 59.1% of the IIRs were narrow patent processus vaginalis (PPV) with a peritoneal veil; for patients with inguinal hernia, 92% of the IIRs were widely opened PPV.[25]

Peng et al reported the successful use of minilaparoscopic procedures in 125 boys (age range, 12-68 months) with multiple peritoneal folds in the hydrocele sac orifice. Modified single-port, double-needle, minilaparoscopic surgery in which an Endo Close needle was used to spread the peritoneal folds and facilitate circular extraperitoneal suturing produced outcomes comparable to those with a two-port laparoscopic procedure, during which a 3-mm grasping forceps was used to grasp the folds around the internal inguinal ring. The authors suggest that the modified single-port technique is safe, effective, and more cosmetically appealing for the management of complicated pediatric hydroceles.[26]

Wang et al reported success with single-site laparoscopic percutaneous extraperitoneal closure of the internal ring in 483 children with hydrocele. Their technique, which uses an epidural and spinal needle, required a median operation time of 18 minutes (range, 10-30 min) and no patient developed intraoperative or postoperative complications.[27]

Scrotal

The scrotal approach, with excision or eversion and suturing of the tunica vaginalis, is recommended for chronic noncommunicating hydroceles. This approach should be avoided if there is any suspicion for underlying malignancy.

In contrast, Alp et al report that the scrotal approach is an effective alternative for the treatment of communicating hydrocele in pediatric patients. In their study of 43 boys (46 testicular units) treated with the classic inguinal approach and 27 boys (30 testicular units) treated with a scrotal approach, operative time was significantly lower in the scrotal group (P < 0.0001), the early minor complication rate did not differ between the two groups, no major complications noted, and none of the patients had hydrocele recurrence after a mean follow-up of 6 months.[28]

Sclerotherapy

An additional adjunctive, if not definitive, procedure, is scrotal aspiration and sclerotherapy of the hemiscrotum using tetracycline or doxycycline solutions. Recurrence after sclerotherapy is common, as is significant pain and epididymal obstruction, making this treatment a last resort in poor surgical candidates with symptomatic hydroceles and in men in whom fertility is no longer an issue.

A review by Taylor et al of aspiration and sclerotherapy treatment for hydroceles in aging men concluded that sodium tetradecyl sulphate (STDS) is the sclerosing agent with the best cure rate after a single injection and rates of adverse effects. Cure rates with STDS were 76% after a single aspiration and injection and 94% after multiple treatments. Patient satisfaction rates at a mean of 40 months were 95%. Complication rates were generally low and much lower than those seen with surgical repair.[29]

Lund et al, in a study of 76 patients with hydrocele testis, found that aspiration and sclerotherapy with polidocanol is an effective treatment with a low recurrence rate. In this prospective, double-blind, randomized study, 36 patients given polidocanol (group 1) were compared with 41 patients given placebo (group 2). Recurrence after the first treatment was seen in 16 (44%) of the polidocanol patients and in 32 (78%) of the placebo patients. Recurrence after re-treatment with polidocanol in both groups was seen in four patients (25%) in group 1 and in 14 patients (44%) in the former placebo group. The overall success rate of treatment in group 1 was 89%.[30]

Jahnson et al reported that in patients undergoing sclerotherapy, adjuvant treatment with an antibiotic and a nonsteroidal anti-inflammatory drug resulted in an increased cure rate and a lower incidence of subclinical epididymitis/swelling (SES). In their prospective observational study of 191 men who underwent polidocanol sclerotherapy for hydrocoele/spermatocoele, the patients who received anti‐inflammatory medication after the procedure had a decreased rate of SES (5% vs 26%) and an increased cure rate (96% vs 88%), compared with those who did not receive anti-inflammatory medication. The usual regimen in the treatment group was trimethoprim 160 mg (occasionally ciprofloxacin 500 mg) twice daily and diclofenac 50 mg three times daily for 10 days.[31]

Preoperative considerations are minimal because outpatient treatment is the routine. Nothing by mouth (NPO) provisions are age- and institution-dependent. Proper provisions for postoperative transportation and observation are arranged prior to surgery.

Intraoperative considerations during inguinal repair include meticulous attention to spermatic cord structures. A "no-touch" approach to the reactive testicular vessels and delicate vasa helps minimize complications. Excessive dissection around the testicular vessels may result in thrombophlebitis of the pampiniform plexus. The distal processus is spatulated widely to provide free drainage of scrotal fluid. The proximal processus is ligated above (deep to) the internal inguinal ring. Failure to identify a patent processus during inguinal exploration should prompt (1) a thorough reexamination of the cord structures and (2) partial or complete excision of the hydrocele or needle aspiration of only the hydrocele prior to closing.

During scrotal approaches, excision of redundant tunica vaginalis (with or without eversion) and suturing of the reflected tunica behind the epididymis results in a postoperative testis that is more easily and more reliably examined. Care must be taken to not injure the vas or epididymis during this procedure. A running hemostatic suture around the line of excision is helpful for assuring hemostasis. Plication of the sac (Lord procedure) is another technique useful for management of large hydroceles. Electrocautery fulguration of the edge of the excised tunica vaginalis promotes scarring and decreases recurrence while decreasing operative time.

Unexpected findings may be dealt with, as appropriate, either for the scrotal approach or by converting to an inguinal approach (eg, testicular tumors). If a testicular tumor is encountered, biopsy with frozen section and orchiectomy with resection of the spermatic cord up to the internal ring is warranted if tumor is confirmed. Placing a drain in the dependent portion of the scrotum is prudent for large hydroceles. A nonsuction drain such as a Penrose can be removed within the first 24-48 hours after surgery. If a drain is not used, expect a large hematoma and significant edema. Often, this enlargement is worse than the original problem, although it is almost always transient.

Children undergoing inguinal herniorrhaphies for repair of communicating hydroceles generally recuperate with minimal discomfort and exceedingly few restrictions. Tub baths are to be avoided for 5-7 days. The wounds of diaper-aged children are sealed with tissue adhesive or occlusive dressing. No activity restrictions are required, and nonnarcotic analgesics are used minimally.

Patients undergoing scrotal approaches benefit from supportive dressings in a scrotal support or athletic supporter. Rest and avoidance of vigorous activity help minimize discomfort. Showers may be resumed within 24-48 hours. Occasional doses of synthetic or semisynthetic narcotics may help relieve postoperative discomfort. Adult patients should be counseled that the hydrocele may transiently reaccumulate for a month or so postoperatively owing to edema.

At least one postoperative follow-up visit is recommended. For small infants, patients with chronic recurring hydroceles, or patients with unsuspected intraoperative findings, more protracted follow-up evaluations may be warranted biweekly, monthly, or every 2-3 months to ensure complete recovery and normal testicular size and architecture.

Complications are largely avoided with meticulous dissection and gentle tissue handling. In addition, extensive dissection should be avoided, as it increases the risk for nerve damage, vascular damage leading to testicular atrophy, and postoperative hematomas.

Injury to spermatic cord structures can occur. The vas or testicular vessels may be injured in 1-3% of inguinal approaches. Some testicular shrinkage has been described in nearly 10% of children undergoing inguinal hernia repair.

Recurrence of the hydrocele after inguinal approaches is most often reactive in nature and usually resolves within several months. Rarely, aspiration or scrotal surgery is warranted.

Either poor intraoperative hemostasis or excessive cord dissection (with inguinal approaches) may result in postoperative bleeding. Hematomas typically resolve over time. If the patient has evidence of ongoing bleeding or is extremely symptomatic, exploration and hematoma evacuation is warranted.[32]

The Ilioinguinal/genitofemoral nerves may be entrapped or divided during inguinal approaches. The injury may be temporary or permanent.

Postoperative wound infections are quite uncommon, particularly in children. Wound infections should be managed with antibiotics and, if necessary, opening the wound.

Inguinal repairs of communicating hydroceles are exceedingly successful, with a less than 1% recurrence rate. If a unilateral approach is completed, the small but recognized risk for a metachronous hydrocele or inguinal hernia developing remains, but the rate is likely less than 10%. Likewise, recurrence after tunica excision is also uncommon.

Many surgeons have begun to advocate routine diagnostic laparoscopy of the contralateral groin in patients (particularly children) with unilateral hernias. The premise is that this will permit identification and repair of unsuspected contralateral hernias prior to clinical recognition. However, many more patent processus are being ligated than true hernias are being repaired. Whether an increased use of this technique will reduce the incidence of hydroceles in older children or adults remains to be seen. Furthermore, whether utilization of this intraoperative modality is of any utility in inguinal hydrocele repairs is open for debate.

Medical management, or, more importantly, prevention of patent processus vaginalis, has been theorized as possible after full elucidation of the intricate molecular processes that control fetal cell migration, proliferation, and adherence. Although the idea of preventing hydroceles or indirect hernias is interesting, it is far from being applicable in clinical medicine.

In 2000, the World Health Organization (WHO) launched the Global Program to Eliminate Lymphatic Filariasis (GPELF), with a goal of eliminating lymphatic filariasis by 2030. In 2018, three of nine countries participating in the program in Southeast Asia had eliminated LF and Bangladesh was in reach of its elimination goal.  In 2020, the program had thus far prevented or cured 74.9 million infections, resulting in a 84.2% reduction of lymphodema and hydrocele.[33]