The side effects and complications of vasectomy are divided into “early” and “late” categories, depending on when they occur.

Early complications:

After vasectomy, the testes continue to produce sperm, and the passage of the sperm into the obstructed epididymis and vas deferens causes increased intraluminal fluid pressure. Dilatation of the efferent ductules occurs. SPERMATOCELES, cystic structures that result from the obstruction and dilatation of the efferent ductules, may form.  Spermatoceles contain milky fluid composed of sperm, lymphocytes, and cellular debris. At sonographic examination, spermatoceles are well-defined epididymal hypoechoic lesions usually measuring 1-2 cm and demonstrating posterior acoustic enhancement. They are usually irregular, with fine low-level internal echoes and sometimes septations (Fig. 3).

In addition, DILATATION OF THE VAS DEFERENS can be seen (Fig. 4). Color Doppler sonography of the epididymis usually shows hypovascularity, whichindicates the absence of an acute inflammatory process.

Short-term bleeding-related complications after a vasectomy may sometimes occur. These include bleeding from the surgical site or a hematoma. HEMATOMAS are the most common early complicationy, with an incidence of about 2%. Scrotal haematoma is thought to occur most commonly due to damage to the venous structures, most notably the pampiniform plexus. Given the elasticity of the scrotum and its poor tamponading effects, any bleeding will be afforded ample space to form a haematoma. Exploration and drainage of the scrotum is the only treatment available for large scrotal haematomas which are worsening, or not responding to conservative management. The patient's chief complaint soon after the vasectomy procedure is painful scrotal swelling. Sonography features of a scrotal hematoma include enlargement of the epididymis with an ill-defined border and a large amount of fluid collected around the testis and epididymis with various echogenicity, depending on the stage of the hematoma (Fig. 5).

SURGICAL SITE INFECTION

Any time incisions or instruments are inserted into the body, there’s potential risk for infection after the procedure. This includes wound, urinary and epididymal infection. The incidence of infection varies between 0.2–1.5%; generally, infections are mild and limited to the wound site, but Fournier’s disease has been reported (Fig. 6).

Other reported early complications of a vasectomy are EPIDIDYMITIS and ORCHITIS. The epididymis is a duct located behind the testicles. It allows sperm to flow to the vas deferens. When a man has a vasectomy, sperm can still flow from the epididymis to the vas deferens, but becomes backed up because the vas deferens has been cut. In some men, this can cause inflammation of the gland, or epididymitis or orchitis. Symptoms associated with the condition include pain and swelling. Epididymitis and orchitis following vasectomy occurs in an estimated 1 to 3 percent of all men after a vasectomy. At ultrasound increased size and, depending on the time of evolution, decreased, increased, or heterogeneous echogenicity of the affected organ are usually observed. The inflammation produces increased blood flow within the epididymis, testis, or both (Fig. 7 and Fig. 8).

Other vasectomy-related early complitations: Varicoceles, hydroceles, epididymal cysts and testicular cysts (Fig. 9) are possible findings after avasectomy. However, these abnormalities occur at a similar frequency to patients with or without a prior vasectomy.

Long-term complications:

When the obstructed epididymis and efferent ducts are no longer able to compensate for the increased intraluminal pressure by means of dilation and increased fluid absorption, late postvasectomy findings are observed. At this stage, extravasation of sperm into the walls and interstitium of the epididymis and vas deferens elicits histopathologic reactions, a foreignbody giant cell reaction occurs and SPERM GRANULOMAS are formed. A sperm granuloma, also called epididymitis nodosa, occurs after a vasectomy in up to 40% of patients; is a lump of sperm that can cause small bumps or cysts that range from 1 millimeter to 1 centimeter in size. They don’t usually cause any symptoms; only 3% of these patients experience pain. Sperm granuloma is shown as a well-circumscribed heterogeneous mass on sonography ( Fig. 10), and is most commonly found at the ends of the severed vas deference.

POST VASECTOMY PAIN SYNDROME is an uncommon condition that occurs after a vasectomy over a long period. This condition is possibly the most troublesome and vexing complication of vasectomy, characterized by scrotal pain during ejaculation or sexual activity. It can persist for months to years. Because this syndrome develops years after a vasectomy, this specific condition may not be discoverable when referring to the scrotal sonography. 1–2% of patients after vasectomy experience this complication. This is believed to result from a longstanding obstruction of the efferent ductules of the epididymis (congestive epididymitis) or perineural inflammation following extravasation of sperm into the interstitium (sperm granuloma).  On sonography, these histopathologic changes present as an overall thickening and distension of the epididymis with a diffuse, finely speckled appearance, representing tubular ectasia of the epididymis (Fig. 11)

Treatment options include excision of sperm granuloma, epididymovasectomy, and vasectomy reversal. Incidence of chronic pain is reportedly decreased by injecting local anaesthetic agents into the vas at the time of surgery.

VASOVENOUS FISTULA

A vasovenous fistula is a very rare complication of vasectomy. This condition occurs when multiple blood vessels adhere to the vas deferens that then become injured when a man has a vasectomy. This can result in the pooling of blood that leads to the development of a fistula, or abnormal connection between the vas deferens and nearby blood vessels. Symptoms of a vasovenous fistula may include blood in urine or ejaculate. While this complication is very rare, seek immediate medical attention if you have these symptoms.