Overview of Dorsal Penile Nerve Block
A dorsal penile nerve block is a way to numb the penis using a small amount of anesthetic. This technique is very useful for urologists (doctors who specialize in diseases of the urinary tract and male reproductive organs) and is also helpful for doctors in emergency departments who often need to treat urgent conditions such as paraphimosis (a penis condition where the foreskin cannot be pulled back over the tip of the penis).
Anatomy and Physiology of Dorsal Penile Nerve Block
The penis gets its nerve supply from some specific nerves that originate from the spine, specifically sacral nerve roots (the bottom part of the spine) S2 through S4. These nerves come through the pudendal nerve. This nerve is located close to the pudendal artery inside a narrow channel in our bodies called the pudendal canal.
In this canal, the pudendal nerve splits into smaller branches. These include the dorsal penile nerves which supply the penis, and the perineal branch which supplies other areas in the region between the legs.
Each dorsal nerve takes a route under a bone near the lower groin area (the inferior ramus of the pubis) and lies deep under the ligament that supports the penis. These nerves tend to stay in their own space and rarely interact with each other. They follow a direct path within a thick membrane around the penis, next to the vessels supplying the penis with blood.
The small piece of skin connecting the head of the penis (frenulum) gets its nerve supply mainly from the dorsal penile nerves. However, it also receives supply from a branch of the perineal nerve.
Why do People Need Dorsal Penile Nerve Block
A dorsal penile nerve block is a medical procedure that is often used in various situations to help alleviate pain in the penis. Here are a few examples:
* If a man needs to undergo circumcision, which is the removal of the foreskin covering the penis, this procedure can be performed under local anesthesia to numb the pain, or it can be used after the operation to help soothe post-surgery discomfort if general anesthesia was used.
* It can also be used during a dorsal slit procedure. This is a treatment method often used if a man has a too-tight foreskin that can’t be pulled back, a condition known as phimosis.
* In the case where a man has an unfortunate situation called paraphimosis, which is when the foreskin can’t be pushed back to its normal position, making it trapped behind the penis’s head, a dorsal penile nerve block can be used to help alleviate the pain during treatment.
* It can also provide pain relief if a man needs a medical procedure to repair a penile laceration, which is a cut or tear in the penis.
* Lastly, this procedure is often used when a man has to undergo treatment to free penile skin that has gotten caught in the zipper. This is often referred to as a zipper injury.
When a Person Should Avoid Dorsal Penile Nerve Block
There are several reasons why some people might not be able to have an injection. The most common reason is if there’s an infection in the skin or soft tissue where the injection would go. Another common reason is an allergic reaction to the numbing medicine, known as local anesthetic, that’s often used with injections.
Other reasons relate more to the circumstances of the person and the situation. For example, if a person has a condition that causes them to bleed easily, called bleeding diathesis, an injection could be too risky. An injection might also not be possible if a person is uncooperative or very afraid of needles.
Equipment used for Dorsal Penile Nerve Block
Doctors often have their own preferred setup when it comes to the tools and numbing medicine they use. However, there is a common list of what is typically needed:
- Preparation solution for the skin, such as Chlorhexidine or povidone-iodine. It cleans the area before the procedure.
- A disposable drape, which is a material used to cover the surrounding area to maintain cleanliness.
- 4 x 4 gauze swabs, used for cleaning and wiping the area.
- Two 10-mL syringes, which are instruments that help draw out or inject liquid.
- Needles of different sizes:
- A 19- or 21-G syringe for numbing deeper areas if needed.
- A 25-G syringe for applying numbing medicine to the skin.
- An 18-G syringe for drawing up the numbing solution.
- A numbing solution that doesn’t contain adrenaline or epinephrine, which would commonly be called a local anesthetic.
Who is needed to perform Dorsal Penile Nerve Block?
A numbing procedure on the penis, known as a dorsal penile nerve block, can be done safely by a person who is trained to prescribe and use local anesthetics (a medicine that causes numbness). This person has dedicated knowledge of how to make a specific part of your body feel numb, so you don’t feel any pain.
If this person has prepared well in advance, they don’t usually need any help. However, if they’ve never done this particular procedure before, it can be helpful to have a colleague who is experienced in numbing procedures present to assist.
Having an assistant can also be helpful in case something is accidentally dropped or forgotten during the procedure. The assistant can quickly replace any items, ensuring the procedure continues smoothly. Doctors and other healthcare providers should also talk with the patient to help ease any worries and ensure the numbing procedure works as effectively as possible.
Preparing for Dorsal Penile Nerve Block
Before starting a medical procedure that requires local anesthesia, it’s crucial to have all the necessary tools and equipment ready and within reach. It’s also essential to get the patient’s permission for both the anesthesia and the actual procedure that will follow. Knowing the patient’s weight, either by measuring it or making an educated guess, is also required.
The local anesthesia that will be used will be selected based on the type of anesthesia the doctor chooses, the patient’s weight, and the concentration of the anesthesia available. The amount of anesthesia given will depend on the hospital’s guidelines or the standard rules if the hospital doesn’t have specific guidelines. Here are the maximum safe dose guidelines for certain anesthesia:
* Lidocaine 1%: 10 mg/mL (3 mg/kg)
* Lidocaine 2%: 20 mg/mL (3 mg/kg)
* Levobupivacaine 0.25%: 2.5 mg/mL (2 mg/kg)
* Levobupivacaine 0.5%: 5 mg/mL (2 mg/kg)
It’s incredibly important to accurately calculate the maximum safe dose of anesthesia. If the medical professional isn’t comfortable doing this, they shouldn’t be the one to give the local anesthesia.
In preparation for the procedure, the patient should be lying flat on their back and be comfortable. Any areas that the procedure will involve, like the lower belly area, penis, or testicles, should be cleaned to remove any potential sources of contamination. After cleaning, the areas should be covered with a sterile, one-time-use covering to keep the area clean and sterile.
How is Dorsal Penile Nerve Block performed
Dorsal penile nerve block is a procedure used to provide pain relief by numbing the penis. This can be done in two different ways, through a ring block at the base of the penis, or a dorsal penile nerve block near the pubic bone, or a combination of both. Let’s further understand these techniques.
In the dorsal penile nerve block technique, the goal is to inject an anesthetic, a medication that numbs the area, deep into the tissues located on either side of the suspensory ligament, a structure that supports the penis. The process starts with injecting a small amount of anesthetic at the skin at the back base of the penis with a small needle, causing a small bump of anesthetic under the skin. A larger needle may then be used if necessary, inserted through the small bump until it touches the pubic bone, located in your lower abdomen. The pubic bone serves as a guide for how depth for the injection.
Afterwards, the needle is adjusted slightly to pass underneath the pubic bone, before injecting the anesthetic. This process is repeated on the opposite side, ensuring to prevent damage to the penis’s supportive ligaments and blood vessels.
Different doctors might have different styles of doing this. Some might perform the entire block through the middle and carefully angle the needle to avoid midline structures that lie in the center. Others may prefer performing the procedure just lateral to the midline to reduce risk to these central structures, but this might involve multiple injections.
The frenulum, a sensitive area of the penis, might not be fully numb because of the way it receives its nerve supply. In such situations, additional anesthetic may be applied to the base of the penis or a part of the lower surface of the penis.
For the ring block technique, at least two injection points are needed to have a successful numbing effect encircling the penis. The injections are typically applied on either side of the penis to create a “ring” of anesthesia. The doctor needs to be cautious not to insert the needle too deeply or injure any blood vessels or the urethra, the tube that carries urine, as this may lead to a penis bruise.
Possible Complications of Dorsal Penile Nerve Block
After a medical procedure, the most common issue patients usually face is feeling pain during any later procedures. This discomfort could mean the initial numbing procedure wasn’t fully successful, the patient is experiencing the sensation of touch, or ideally, the patient may not have waited long enough for the anesthetic to take full effect (usually this takes about 10-15 minutes). The pain felt while injecting the numbing drug can be lessened by slowly injecting the drug.
Bleeding and bruising are also common, but can typically be managed with pressure and bandages.
A numbing drug mixed with adrenaline, or epinephrine, should never be used because it’s been linked to tissue damage and inadequate blood supply.
What Else Should I Know About Dorsal Penile Nerve Block?
Dorsal penile nerve blocks are a useful method for numbing the penis quickly, allowing doctors to treat various conditions without the need for a full anesthesia. This technique is beneficial in both scheduled and emergency situations, as it can alleviate the need for general anesthesia, enabling quicker treatment. It’s important for healthcare providers like nurse practitioners or primary care doctors, who want to perform this procedure, to understand the structure of the penis to prevent any complications.
A comprehensive study has shown that dorsal penile nerve blocks are more effective at providing pain relief compared to a cream that also numbs the skin (known as EMLA). There’s only a small chance of minor side effects like the procedure not working properly (4% to 8% of cases) or causing a collection of blood beneath the skin, known as a hematoma (5% of cases).