Testicle and Epididymis Anesthesia 

Embryology

Anesthesia of the testicle and epididymis is best understood starting from the embryological origin of the respective structures. The testes are embryologically derived from the same level as the kidneys and, therefore, share a common level of innervation, that being the T10-L1 level for pain conduction and T10-L2 for sympathetic innervation. As the fetus matures, the testes descend into the scrotum. The scrotum is innervated anteriorly by the ilioinguinal and genitofemoral nerves, while the posterior portion of the scrotum is innervated by the perineal branches of the pudendal nerves. Anatomy is shown in the images below.

The afferent fibers for the internal contents of the scrotum run in the spermatic cord. It is at this site that an anesthetic nerve blockade is best approached, as the nerves are relatively superficial to the skin as they run through the spermatic cord. With a relatively noninvasive and simple technique, anesthesia of the testicles and epididymis can be achieved.

In the images below, note that the nerves that are involved with the innervation of the scrotal sac include the iliohypogastric and ilioinguinal nerves and the genitofemoral nerves, along with a branch of the pudendal nerve on the posterior surface of the scrotal sac. Therefore, administration of local anesthetic to the spermatic cord itself, while establishing anesthesia of the testicle and epididymis, does not establish anesthesia of the overlying skin.^[1]

• Surgery on the testicle or epididymis
• Chronic pain states of the testicle or epididymis
• Diagnostic blocks prior to a neuroablative procedure to relieve pain associated with the respective structures

• Absolute contraindications

  • Patient refusal
  • Active infection over the site to be entered with a needle
  • Coagulopathy
• Relative contraindications

  • Systemic infection
  • Allergy to medications to be used during the procedure
  • Gross abnormality in the anatomy of the region to be entered with a needle

General anesthesia

• If surgery is indicated on the testicle or epididymis, then certainly a general anesthetic is always an option. Obviously, this may be one of the only feasible options if the patient refuses to undergo a regional technique for the surgical intervention.
• A patient's refusal to undergo regional anesthesia for surgical procedures of the testicle and epididymis may often be rooted in the belief that he will be awake during the procedure and would just rather be "all the way asleep" for a surgery in this sensitive region. This can usually be addressed with some discussion of the block and the assurance that every effort will be made to make the patient comfortable, generally including monitored anesthetic care or conscious sedation. Again, note that patient refusal is one of the few absolute contraindications for performing any regional anesthetic technique.
• For more information, see Procedural Sedation.

Spinal or epidural anesthesia

• Anesthesia for surgery on the testicles and epididymis can easily be obtained by performing either a spinal anesthetic (with an insensate level of at least thoracic level 10) or an epidural anesthetic.

  • Often, a spinal anesthetic is chosen because of the short duration of most surgical procedures involving these anatomic structures, the low failure rate of neural blockade, and the avoidance of the sacral nerve root sparing that is associated with epidural blockade.
  • This last point is relatively important because the posterior elements of the scrotum are innervated by the perineal branches of the pudendal nerve, which are derived from the S2-S4 levels.
• In adult patients, caudal anesthesia is generally not performed because of a high failure rate in this population. However, caudal anesthesia is a viable and often used option in the pediatric population for postoperative pain control.

Spermatic cord block

• A spermatic cord block is a relatively simple procedure that can be performed to provide anesthesia to the testicle and epididymis. The relatively superficial position of the spermatic cord near the external inguinal ring makes this an ideal position for placement of local anesthetic and anesthesia of the testicle and epididymis. Note that a spermatic cord block offers anesthesia to only the testicle and epididymis and not the overlying skin, including the scrotum and suprapubic region.
• The spermatic cord block may be repeated as necessary for orchialgia.^[2]

Ilioinguinal, iliohypogastric, genital branch of genitofemoral nerve blocks ^{[3, 4]}

• Anesthesia to the overlying skin, scrotum, and suprapubic regions is achieved with the ilioinguinal and iliohypogastric nerve blocks.^[2]
• The pulsed radiofrequency procedure has been successfully used for chronic groin or orchialgia originating from the above nerves.^[5]
• Patients who do not respond to spermatic cord block may benefit from the following blocks:

  • Periprostatic nerve (pelvic plexus) block: The plexus lies anterior to the rectum at the prostatovesical junction. Transrectal ultrasonographic guidance aids in the localization of the nerves. Major sympathetic and parasympathetic efferent input to the testis is provided by the pelvic plexus.^{[6, 7]}
  • Superior hypogastric plexus block: Long-lasting pain relief is obtained by neurolysis of this plexus in patients with testicular cancer pain.^[8]

This procedure is relatively straightforward and requires a minimal amount of setup to be performed.

• Sterile 10-mL syringe
• Small gauge needle (25 ga) that is 1.5 to 2 inches long
• Solution for sterile preparation (eg, chlorhexidine [Hibiclens], povidone-iodine [Betadine])
• Pair of sterile gloves
• Sterile towels to set up the field
• Local anesthetic of choice, 10 mL

• The patient should be positioned comfortably in the supine position.
• Placing a firm board or support underneath the buttock for the period during the block may be helpful. This accentuates the area and facilitates palpation of the spermatic cord, particularly in patients who are obese.

Spermatic cord block

• Prepare and drape the patient in a sterile fashion.
• Palpate the pubic tubercle on the side that is to be blocked.
• At a point that is 1 cm inferior to and 1 cm medial to the pubic tubercle, make a needle puncture with the attached syringe and local anesthetic solution. (While an overlying skin wheal of local anesthetic can be raised, with a small-gauge needle and slow injection of the infiltrate, a relatively pain-free injection can be performed.)
• In most patients, the spermatic cord can be palpated. Immobilizing the cord during the block with the nondominant hand, between the thumb and index finger, can be beneficial.
• Pass the needle directly downward in a vertical fashion, which brings it into the spermatic cord.
• After a negative aspiration for blood, inject approximately 3 mL of the solution into the cord. Repeat this step with some cranial and then caudal angulation of the needle so as to fan out the medication within the cord itself. Aspirate before each successive injection.

Ilioinguinal nerve block

• Place the patient supine with a pillow under the knees.
• Palpate the anterior superior iliac spine (ASIS).
• Prepare the skin with antiseptic solution.
• Infiltrate the skin with lidocaine 1% 0.5 mL at a point 2 inches medial and caudal to the ASIS. Then insert a 25-gauge 1.5-in needle at that point and advance it at an oblique angle toward the pubic symphysis. Take care to not advance the needle too deep, into the peritoneal cavity. The image below indicates positioning. Ilioinguinal, iliohypogastric, genital branch of genitofemoral nerve blocks.
• After negative aspiration, inject 5-7 mL of lidocaine 1% in a fanlike manner as the needle pierces the fascia of the external oblique muscle.

Iliohypogastric nerve block

• This procedure is the same as the procedure for the ilioinguinal nerve block except that the needle entry point is 1 inch medial and caudal to the ASIS. The image below indicates positioning. Ilioinguinal, iliohypogastric, genital branch of genitofemoral nerve blocks.

Genital branch of genitofemoral nerve block

• Identify the pubic tubercle and the inguinal ligament.
• The needle entry point is just lateral to the pubic tubercle and just below the inguinal ligament. Take care not to advance the needle too deep, into the peritoneal cavity. The image below indicates positioning. Ilioinguinal, iliohypogastric, genital branch of genitofemoral nerve blocks.
• After negative aspiration, inject 5-7 mL of lidocaine 1%.

• Retraction of the abdominal pannus is occasionally needed during this procedure in patients who are obese. This can be accomplished with the aid of an assistant or some appropriately placed tape.
• Aspiration prior to injection of local anesthetic is an integral part of this procedure. If aspiration is noted to be positive, withdrawal of the needle with application of pressure for 2-3 minutes can often prevent the formation of a hematoma.
• Good patient communication and a description of what is happening during the procedure is paramount in helping the patient relax during the procedure. It also can help decrease the patient’s movement; this, in turn, decreases the risk of inadvertent puncture of alternative structures and helps ensure the success of the block.

• Bleeding
• Infection
• Intravascular injection
• Failure of the block
• Vasovagal reaction during the block or procedure itself: This mandates prior intravenous access before the procedure is performed.
• Puncture of the surrounding structures is possible, including the ductus deferens and the vasculature in the spermatic cord and the unlikely puncture of the bladder, bowel, and femoral vessels.
• A temporary or sustained neurapraxia is a possibility, as with almost any procedure involving a regional anesthetic technique.