Overview of Transabdominal Plane Block
Regional anesthesia is a type of pain control method used during abdomen-related surgeries. It works by blocking certain nerves in the body. Several different methods are available and often, a special type of machine called an ultrasound is used to guide them. This is the case for a procedure called the transversus abdominis plane (TAP) block. During this procedure, a local anesthetic, or numbing medicine, is injected into the space between certain muscles in your abdomen. The TAP block only numbs the area where the surgery will happen, but not internal organs.
One of the main uses of a TAP block is for managing pain after surgery. Different types of surgery can benefit from a TAP block, from minor outpatient procedures to more serious surgeries like removing the gallbladder, appendix or kidney, or even after a kidney transplant. If the surgery is only on one side of the body, then only that side gets the TAP block. But if the surgeon needs to make cuts in the middle of your stomach or across it, like for hernia repair, C-sections, hysterectomies (removal of the uterus), or prostatectomies (removal of the prostate), then TAP blocks can be given on both sides of the abdomen.
The TAP block helps lower the need for strong pain medicines called opioids after surgery. Usually, the TAP block is performed while you are still under anesthesia, either right before the surgeon makes the first cut or just as you are waking up from anesthesia. The effectiveness of the TAP block depends on how evenly the numbing medicine spreads across the area between the muscles in your abdomen.
TAP blocks are becoming more and more common for controlling pain after stomach surgeries. However, like other medical procedures, TAP blocks have their pros and cons and are not always suitable for everyone. That’s why it’s important to discuss this with your doctor before having surgery.
Anatomy and Physiology of Transabdominal Plane Block
The front wall of your belly consists of multiple muscles: rectus abdominis, external oblique, internal oblique, and transversus abdominis. Inside these muscles, there is a section known as the TAP block which lies between the internal oblique and transversus abdominis muscles. This area contains nerves that are rooted from the backbones from T6 to L1. Understanding this can give more insight into how these nerves affect your body.
The sensation you feel in the frontal side of your belly comes from spinal nerves that have branched into anterior and posterior sections. The rami, a collected mass of nerves, divides into two branches, the anterior and lateral cutaneous nerves. The nerves coming from the segments T6 to T11 are known as intercostal (IC) nerves. They provide sensation to the skin and muscles on the front side of your belly. The T9 to T11 IC and T12 subcostal (SC) nerves specifically go through the TAP block at the side of your body.
The lower thoracic IC and SC nerves provide sensation to the skin below the belly button area, which is between the middle and the line coming down from the collarbone. The L1 lumbar plexus gives birth to the ilioinguinal (II) and iliohypogastric (IH) nerves. These nerves give feeling to the upper hip, groin, and thigh. All of these nerve branches travel between the transversus abdominis (TA) and internal oblique (IO) muscles in the TAP block.
The existence of the TAP block was first acknowledged by Rafi in 2001. He suggested this block be performed using anatomical landmarks at the triangle area at the side of the back known as the Petit triangle. The Petit triangle is formed by the iliac crest at the bottom, the latissimus dorsi at the back, and the external oblique at the front, with the tip being the rib cage.
These types of blocks unfortunately have unpredictable success due to their blind ends. O’Donnell used the term TAP block in 2006 and suggested modifying Rafi’s initial description by using a double pop technique. In 2007, another group suggested using ultrasound guidance to locate the intermuscular planes and changing the access point to the side of the body rather than the Petit triangle. By 2010, another group showed that the under-costal approach covered more nerves and was therefore more effective.
Why do People Need Transabdominal Plane Block
A TAP block is a type of anesthesia used to relieve pain after surgery on the abdominal wall, which includes the stomach area. It can be used during a variety of surgeries, including both open and laparoscopic (keyhole) procedures. It is a simpler and safer alternative to epidural anesthesia (which is given in the spine) for controlling pain after surgeries in the stomach area.
In some cases, a TAP block is only applied to one side of the body. This is known as a unilateral block and it might be used for surgeries that only involve one side of the body, such as removal of the appendix, gall bladder, kidney, or for a kidney transplant.
In other instances, a TAP block is applied to both sides of the body. This is known as a bilateral block and it might be used for surgeries involving the middle or across the stomach area. These could include repair of a ventral hernia (a bulge in the stomach wall), umbilical hernia (bulge near the belly button), exploratory laparotomy (opening up the stomach to investigate a problem), colostomy closure (closing up an opening made for waste to leave the body), C-section (delivery of a baby through the stomach), removal of the uterus (hysterectomy), removing the prostate gland (radical retropubic prostatectomy), weight loss surgery (bariatric surgery), repairing a hernia in the groin (inguinal hernia), and keyhole surgery (laparoscopic surgery).
Besides offering pain relief after surgeries, TAP blocks can also be used to manage chronic pain, that is, pain that lasts for a long time.
When a Person Should Avoid Transabdominal Plane Block
There are certain instances where a medical procedure can’t be performed:
- If a patient doesn’t want to have the procedure, it won’t be done.
- If there is an infection on the part of the body where the procedure would need to take place, it’s not safe to perform it.
- If a patient is allergic to local anesthesia (LA)—a medication used to numb a specific area of the body—, the procedure can’t be conducted.
Doctors also need to be extra careful with certain patients before deciding to perform this procedure. This includes:
- Patients who are on medication to prevent blood clotting (therapeutic anticoagulation). The procedure could cause too much bleeding.
- Pregnant women, because the procedure might pose risks to the unborn baby.
- People in certain physical conditions like being too skinny, weak, or elderly. For them, identifying the exact places on the body to perform the procedure (anatomical landmarks) could be challenging.
Equipment used for Transabdominal Plane Block
To perform a procedure known as a TAP block, which is a type of anesthesia that helps to numb certain parts of your body, doctors need specific tools and materials. Here’s a simplified list of what your doctor might use:
An ultrasound machine with a linear-shaped attachment. If you have a larger body type, they might use a curved attachment instead. This machine helps them locate the exact area for the anesthesia.
A sterile cover for the ultrasound attachment, along with sterile gel to aid the ultrasound process, both of which keep everything clean and reduce the risk of infection.
Your doctor will also use clean towels, gloves, and skin disinfectants like chlorhexidine 2% to maintain a sterile environment.
A special needle, called a nerve block needle, will be used to deliver the anesthesia. This needle can range from 50 mm to 100 mm long and be either 20-gauge or 21-gauge with attached tubing.
They will have two 20 mL syringes filled with the anesthesia solution, which includes agents such as ropivacaine, bupivacaine, or liposomal bupivacaine.
If you’re awake during the procedure, your doctor may use a 5 mL syringe filled with lidocaine to numb the skin first.
Throughout the procedure, they will also monitor your vital signs using tools like an EKG, pulse oximeter, and a blood pressure monitor to ensure your body responds well to the anesthesia.
Overall, this host of materials helps your doctor to safely and effectively carry out a TAP block procedure, numbing the specific area required for your treatment.
Who is needed to perform Transabdominal Plane Block?
A TAP block, a type of anesthesia, should be done by a medical professional who is specially trained in regional anesthesia, like an anesthesiologist. This anesthesiologist knows exactly how to do this procedure and ensure it’s done correctly. In addition to this, there’s also a need for another medical staff, like a nurse. This second person will make sure to double-check everything before the procedure starts, using a process called “preprocedure time out”.
During the procedure, this second person uses a device known as the US to help assist the anesthesiologist, and also helps with the injection of a medicine called LA. As the anesthesiologist positions the needle, this second medical staffer will follow the anesthesiologist’s instructions on when and how much LA to inject. So, while the anesthesiologist manages the main part of the procedure, the second healthcare provider is there to support and make sure everything is done properly and safely.
Preparing for Transabdominal Plane Block
Before your doctor performs a procedure called a TAP block, there are a few steps they need to take:
- Firstly, they will talk to you about the procedure and what it involves, including any potential risks and benefits, as well as other options for managing your pain. This is called getting your informed consent.
- Then, they will make sure you have an IV (a needle put into your vein) in place for the procedure.
- They will also make sure you are being continuously monitored with an EKG machine to track your heart activity, a pulse oximeter to measure your oxygen levels, and a blood pressure cuff, which should get checked every 5 minutes.
- Next, they will have you lie flat on your back and uncover your abdomen.
- They will then clean the skin of your upper and lower abdomen with a special germ-killing solution.
- After the solution dries, they will place sterile towels around the area where the procedure will be done.
Before your doctor starts the procedure, they will do a final check. This is also known as a “time-out”. They will confirm your name, your medical record number, date of birth, allergies, and the specific procedure that they will perform.
How is Transabdominal Plane Block performed
There are several techniques for a procedure known as a Transversus abdominis plane (TAP) block, which is used to numb the area of your abdomen before surgery. These techniques are based on how the TAP block area (the part of your body that’s being numbed) is found. Here’s a list of different TAP block methods:
- The first is the landmark-guided TAP block at the level of the Petit triangle,
- The second is the ultrasound-guided (US-guided) TAP block that can be located in the subcostal, lateral, and posterior approach,
- The last one is the laparoscopic-guided TAP block. This involves viewing from inside the abdominal cavity and feeling 2 “pops” or loss of resistance with the needle from outside the abdomen during surgery.
The ultrasound-guided technique is considered the best because it’s easy for the doctor to see images and safe for you because it lets the doctor see the needle before injecting a local anaesthetic (medicine to numb a specific area of your body). For these techniques, you’ll need to lie on your back, though sometimes you might be tilted to the side for what’s called the ‘posterior approach’.
During the procedure, the doctor will identify the layers of muscle in your abdomen using ultrasound. They’ll infiltrate or numb your skin using a medicine called lidocaine (if you happen to be awake), before penetrating the skin with the block needle. This needle will be watched in real time using ultrasound for safeness. They’ll then inject a local anaesthetic slowly between the internal oblique (IO) and the transversus abdominis (TA) muscles. As this is injected, these muscles will start to separate, which is a process known as ‘hydrodissection’.
Three approaches are mentioned here for US-guided TAP block to target the area anatomically:
First, the Subcostal approach that targets the front part of your abdominal wall under the rib cage. The goal here is to put the local anaesthetic in the space between the TA muscle and the posterior rectus sheath. This blocks the anterior cutaneous nerves which gives numbness for open or laparoscopic cholecystectomy surgeries.
Second, the Lateral approach that targets your abdominal wall on the side. The goal here is to put the local anaesthetic in the space between the TA and IO muscles. This blocks the anterior cutaneous nerves, providing numbness for most abdominal surgeries, for example, laparoscopic surgery, open appendectomy, ventral hernia repair and some others.
Third, the Posterior approach targets your TAP compartment at the back of your body, providing numbness for certain surgeries like kidney removal or transplant.
There are other types of blocks for specific surgeries such as the rectus sheath block and the ilioinguinal and iliohypogastric block.
The rectus sheath block targets the compartment between a muscle in your abdomen known as the rectus abdominis muscle and the posterior rectus muscle sheath. This block provides numbness for surgeries involving midline vertical or paramedian abdominal incisions such as exploratory laparotomy incisions, umbilical surgeries and umbilical port incisions for laparoscopic surgery.
The ilioinguinal and iliohypogastric block targets these two nerves within your TAP compartment above the inguinal ligament. This block provides numbness for inguinal hernia surgeries.
In summary, a TAP block uses injection of a local anaesthetic to create numbness in the abdomen for a variety of surgical procedures. The actual technique and approach depends on the exact location and type of surgery being performed.
Possible Complications of Transabdominal Plane Block
Complications from TAP blocks, a type of regional anesthesia for abdomen surgeries, are not common. However, some reported complications from medical literature include:
* Accidental injury to your bowel
* Formation of a blood clot or hematoma
* Accidental cut to your liver or spleen
* Accidental injection into your liver
* Accidental injection into your abdominal cavity of a local anesthetic (LA)
* Formation of a blood clot in your back due to an injury to a blood vessel
* Temporary blockage of the nerve that controls your leg movement
* Local infection at the injection site
* Accidental injection into a blood vessel
* System-wide reaction to the local anesthetic
Doctors recommend using ultrasound (US) guidance instead of just going by the body’s shape and structure to conduct the TAP block. By using US, doctors can increase the success of the procedure and reduce these complications. After implementing US for TAP block procedures, there have been fewer complications reported.
Damage to nerves during TAP blocks is also rare because this procedure relies on a large amount of the LA injected to sufficiently block the nerves in the area, instead of specifically targeting a nerve. If nerve damage does occur, it could be due to direct injury from the needle, a blood clot, or an infection in the local area. Being too aggressive with the needle, especially in slim, older, or weaker patients, could potentially lead to serious complications like injuries to internal organs, blood vessels, and accidental injections into the abdomen or liver.
Cases have also been reported where the injection given for the TAP block spread everywhere and blocked the nerve controlling leg movements, leading to potential leg weakness. This condition can increase the risk of falling. If this happens, the surgical team should be informed immediately, and the patient should be warned about the potential falling risk. When doing a TAP block, the doctors inject the LA into an area between layers of tissue that have a rich blood supply (interfascial plane). To prevent any accidental injection into a blood vessel, which could lead to a serious reaction to the LA called Last (Local Anesthetic Systemic Toxicity), doctors should be careful and check properly before injecting the local anesthetic.
What Else Should I Know About Transabdominal Plane Block?
Thanks to the development of ultrasound guidance, the TAP (Transversus abdominis plane) block, a type of regional anesthesia injection, has become more commonly used for managing pain after surgeries involving the abdomen. The TAP block is a part of an extensive pain relief strategy for abdominal surgeries. This strategy typically uses at least two non-narcotic pain relievers, such as acetaminophen, a nonsteroidal anti-inflammatory drug, gabapentinoids, IV lidocaine, ketamine or a local anesthetic injected at the wound site, in addition to either oral or injected opioids.
One of the advantages of the TAP block is that it can reduce the patient’s need for opioid painkillers after surgery. It also helps lower the chance of postoperative nausea and vomiting. However, it does not seem to make a difference in the patient’s reports of pain intensity. The TAP block has become indispensable because it is safe, easy to perform, and effective in controlling pain as part of a comprehensive pain management strategy. Ultimately, this leads to increased patient satisfaction and contributes to reducing the global opioid crisis.
