Pudendal Nerve Block

What is a pudendal nerve block?

A pudendal nerve block is an injection of medication close to your pudendal nerve in your pelvic region to provide temporary pain relief. Some injections provide prolonged pain relief.

Your pudendal nerve runs from the back of your pelvis to all the muscles and skin in your genital area, including the anus, vagina and vulva, and penis. It’s a part of your peripheral nervous system.

Damage to this nerve from compression, entrapment or other kinds of irritation can lead to pudendal neuralgia. This causes chronic pelvic pain and other symptoms.

What is the purpose of a pudendal nerve block?

A pudendal nerve block has three main purposes:

• Diagnosis: If you’re experiencing pelvic pain, but your healthcare provider doesn’t know the exact source of it, they may perform a pudendal nerve block with local anesthetics. If you experience pain relief from the block, it may mean that the pudendal nerve is the potential source of the pain. If you don’t experience relief, the pain is likely coming from a different source. Diagnostic pudendal nerve blocks can help your provider plan future treatment.
• Treatment: Providers use this block to help treat chronic pelvic pain due to pudendal neuralgia. This injection usually includes a local anesthetic and may be combined with corticosteroids.
• Regional anesthesia: Providers use pudendal nerve blocks to provide regional anesthesia for certain gynecologic, obstetrical and anorectal procedures. These can include vaginal delivery during the second stage of labor, vaginal repairs and hemorrhoidectomies. Less commonly, providers use pudendal blocks for urological procedures. If the nerve block doesn’t work to provide pain relief (analgesia), there are other anesthesia options.

How should I prepare for a pudendal nerve block?

You usually don’t have to do anything special to prepare for a pudendal nerve block.

In some cases, your healthcare provider may recommend sedation for the procedure. If you’re receiving sedation, you’ll need to fast for six to eight hours before it. You’ll also need someone else to drive you home after the procedure.

In any case, your healthcare provider will let you know what to do. Be sure to follow their instructions. Don’t hesitate to ask questions.

Where is a pudendal nerve block given?

Healthcare providers use three main approaches to deliver a pudendal nerve block injection:

• Transvaginal approach (through your vagina).
• Transperineal approach (through your perineum).
• Perirectal approach (next to your rectum).

Providers choose the best method based on your anatomy and the purpose of the block. Your provider may inject only one side of your body or both.

What can I expect during a pudendal nerve block?

The process for a pudendal nerve block varies depending on where your healthcare provider is injecting it and the purpose for it.

Transvaginal approach

The transvaginal approach is common for obstetric and gynecological procedures.

You can expect the following during a transvaginal pudendal nerve block injection:

1. You’ll lie on your back on a medical table with your legs spread apart and your feet in raised stirrups.
2. You may receive a mild sedative through an IV line in your arm to help you relax.
3. With your consent, the provider will use their fingers to gently feel for the ischial spines along the walls of your vagina. This helps them locate where your pudendal nerve is.
4. The provider will gently insert a needle guide device into your vagina called an Iowa Trumpet.
5. The provider will guide the needle through the Iowa Trumpet and give you an injection of a local anesthetic to numb the area where you’ll receive the nerve block. You may still feel a pinch or some discomfort as the needle enters your vaginal wall.
6. They’ll then inject the medication as close to your pudendal nerve as possible. The provider may use imaging guidance, such as ultrasound or fluoroscopy, to locate the exact spot where the injection needs to go.
7. The provider will repeat this procedure on the opposite side of your vagina/pelvic region if you need a bilateral (both sides) block.

Transperineal approach

Providers use the transperineal approach for anorectal and urological procedures, as well as for pudendal neuralgia in men and people assigned male at birth.

You can expect the following during a transperineal pudendal nerve block injection:

1. You’ll lie on your back on a medical table with your legs spread apart and your feet in raised stirrups.
2. You may receive a mild sedative through an IV line in your arm to help you relax.
3. The provider will clean the skin on your perineum with an antiseptic solution.
4. With your consent, the provider will gently insert their finger into your rectum or vagina to feel for your ischial spine. This helps them locate where your pudendal nerve is. They may also use ultrasound imaging to locate your pudendal nerve.
5. They’ll give you an injection of a local anesthetic to numb the area where you’ll receive the nerve block. You may still feel a pinch or some discomfort as the needle enters the skin on your perineum.
6. They’ll then inject the medication as close to your pudendal nerve as possible.
7. The provider will repeat this procedure on the opposite side of your perineum if you need a bilateral block.

Perirectal approach

Providers most commonly use the perirectal approach for anorectal procedures and pudendal neuralgia.

You can expect the following during a perirectal pudendal nerve block injection:

1. You’ll lie on your side on a medical table.
2. You may receive a mild sedative through an IV line in your arm to help you relax.
3. The provider will clean your rectal area with an antiseptic solution.
4. With your consent, the provider will gently insert their finger into your rectum or vagina to feel for your ischial spine. This helps them locate where your pudendal nerve is. They may use a nerve stimulator and electromyography (EMG) to locate your pudendal nerve. Nerve stimulation of your pudendal nerve results in contractions of your sphincter.
5. They’ll give you an injection of a local anesthetic to numb the area where you’ll receive the nerve block. You may still feel a pinch or some discomfort as the needle enters the skin next to your rectum.
6. They’ll then inject the medication as close to your pudendal nerve as possible.
7. The provider will repeat this procedure on the opposite side of your rectum if you need a bilateral block.

Fluoroscopic-guided approach

Fluoroscopy is a medical imaging procedure that uses several pulses (brief bursts) of an X-ray beam to show internal organs and tissues moving in real time on a computer screen. Pain management providers most commonly use this imaging technology for pudendal neuralgia management.

You can expect the following during a fluoroscopic-guided perirectal pudendal nerve block injection:

1. You’ll lie on your stomach on a medical table.
2. You may receive a mild sedative through an IV line in your arm to help you relax.
3. The provider will clean your buttocks area with an antiseptic solution.
4. They’ll give you an injection of a local anesthetic to numb the area where you’ll receive the nerve block. You may still feel a pinch or some discomfort as the needle enters your skin.
5. The provider will then insert the needle under fluoroscopic guidance until they contact your ischial spine.
6. They’ll then inject the medication as close to your pudendal nerve as possible.
7. The provider will repeat this procedure on the opposite side if you need a bilateral block.

What happens after a pudendal nerve block?

After the injection, you’ll rest for 15 to 30 minutes to let the medication take effect. A nurse will also observe you during this time to make sure you don’t have any unexpected side effects. If you’re getting the injection to manage or diagnose chronic pelvic pain, you’ll then be able to go home.

What are the benefits of a pudendal nerve block?

Potential benefits of a pudendal nerve block include:

• Temporary or permanent pain relief, which may help you function better day to day.
• Temporary or permanent reduction of inflammation in your pudendal nerves, which may help it heal.
• Ruling out or confirming your pudendal nerve as the source of pelvic pain.
• Pudendal nerve blocks are a generally safer option as a regional anesthetic compared to general anesthesia. General anesthesia carries risks like cardiopulmonary depression that regional anesthesia doesn’t.

Some people may feel relief within an hour, if they received local anesthetic. If you received an injection of a corticosteroid, it may take a couple of days for it to take effect. It’s important to note that not everyone experiences pain relief from pudendal nerve blocks. You may need to try other treatment options if this is the case.

How successful are pudendal nerve blocks?

The success rate of pudendal nerve blocks varies from person to person depending on the underlying cause of the pain and other factors that can contribute to the pain.

Compared to general anesthesia, studies show that pudendal nerve blocks (as regional anesthesia) achieve a high level of pain control. In addition, people require fewer systemic analgesics, like opioids, to manage pain.

However, up to 50% of all pudendal nerve blocks may fail on at least one side of your body in the case of bilateral blocks. But the average failure rate is about 20%.

Long-term use of pudendal nerve blocks (typically monthly or as needed) can successfully relieve pudendal neuralgia. But studies show that they may not be as effective after two years of use.

What are the risks or complications of a pudendal nerve block?

The most common side effect of a pudendal nerve block is discomfort at the injection site. This often fades within a couple of days. Bleeding and infection at the site are also possible but are less common. Because your sciatic nerve is close to your pudendal nerve, you may have temporary leg numbness and weakness after the procedure.

Serious complications are rare but can include:

• Pudendal nerve damage.
• Injury to the organs close to your pudendal nerve, such as your bladder or rectum.
• Pudendal artery puncture with the injection of local anesthetics. This can cause systemic local anesthetic toxicity, which is potentially fatal.

How long does a pudendal nerve block last?

Pain relief from a pudendal nerve block for those who have chronic pelvic pain can vary significantly. It may last a few days, several weeks, months or even years. Each person responds differently. Some people don’t experience any pain relief.

When should I call my healthcare provider?

Contact your healthcare provider immediately if you experience any new symptoms or complications from the pudendal nerve block, such as an infection or nerve issues like burning pain, tingling or prolonged weakness.

A note from Cleveland Clinic

Pudendal nerve blocks can help treat chronic pelvic pain. But the results can vary considerably from person to person. They’re also effective as regional anesthesia for certain procedures in your pelvic region. If you’re feeling anxious about receiving a pudendal nerve block injection, don’t hesitate to ask your healthcare provider about it and the procedure. They can answer any questions you may have.