Anesthesia in ACL Surgery - An Overview

Introduction

Anterior Cruciate Ligament (ACL) injuries are common among athletes and active individuals, often requiring surgical intervention for effective treatment and recovery. An essential component of any surgical procedure, including ACL surgery, is anesthesia. Anesthesia not only ensures the patient's comfort but also plays a pivotal role in the safety and success of the surgery.

What Are the Types of Anesthesia Used for ACL Surgery?

In ACL surgery, the two primary types of anesthesia used are general anesthesia and regional anesthesia.

• General Anesthesia: General anesthesia induces a state of unconsciousness, rendering the patient completely unaware and unresponsive to pain. It is administered intravenously and often involves the use of inhaled gasses to maintain the anesthesia throughout the surgery. General anesthesia is typically used for more complex ACL surgeries or for patients who prefer to be completely unconscious during the procedure.

• Regional Anesthesia: Regional anesthesia involves numbing a specific part of the body, allowing the patient to remain conscious during the surgery while ensuring they do not feel any pain in the operated area. One common type of regional anesthesia used in ACL surgery is spinal anesthesia, where medication is injected into the spinal canal to numb the lower half of the body. Another option is epidural anesthesia, which involves injecting the anesthesia into the epidural space surrounding the spinal cord.

How Is the Epidural or Spinal Block Done?

Epidural or spinal blocks, commonly used for pain management during medical procedures, are administered in the back for targeted effects. The patient is positioned either sitting up or lying on their side. Before the procedure, the skin is cleansed thoroughly with antiseptic soap to prevent infection. The experienced anesthesiologist applies a numbing agent to the specific area on the back. Although there might be a slight burning sensation, the patient generally feels minimal discomfort. A very fine needle is carefully inserted to introduce either an anesthetic solution (in the case of a spinal block) or a small plastic tube called a catheter (for an epidural block). Once the anesthetic or catheter is correctly placed, the needle is removed.

The medication spreads around the nerves, effectively blocking pain signals. Post the spinal or epidural block, patients typically experience numbness. It's common to feel weakness in the legs to the extent that movement might be temporarily restricted. This sensation is entirely normal and part of the expected effects of the procedure.

What Are the Advantages and Disadvantages of Anesthesia?

1. General Anesthesia:

• During surgery, the patient will be asleep and unaware of what is happening.

• A breathing tube will be inserted to help the patient breathe.

• The main advantage is that the patient will not remember anything after the surgery, which many people find reassuring.

• However, a downside is that it may cause feelings of nausea and sleepiness afterward.

2. Regional Anesthesia:

• Under this anesthesia, one can decide whether to remember the experience; complete unconsciousness is not induced.

• Recovery might be faster, with decreased nausea, leading to easier eating.

• Nevertheless, a minor risk of experiencing a severe headache after the procedure exists.

Most individuals can opt for either anesthesia type without concern. An anesthesiologist will assess health conditions to determine the suitable choice. Both methods are commonly used and generally safe. The likelihood of severe complications, such as heart problems, breathing issues, death, or paralysis, is relatively similar for both anesthesia types.

What Are the Choices for Pain Relief After Surgery?

• IV or oral pain medicines are injected into a vein or taken by mouth to help dull the pain. They may not get rid of the pain totally. These medicines are most often prescribed by the surgeon and used in the recovery room.

• Femoral nerve blocks are single injection blocks or continuous nerve blocks. They can be used to reduce the pain after surgery. Local anesthetics and other drugs are used for these blocks to reduce pain from the femoral nerve. The femoral nerve provides feeling to most of the front of the knee and a large part of the knee joint. These blocks most often last 15 hours. When a nerve catheter is used, the block lasts for as long as the catheter is in place.

What Pain Relief Options Are Available Following Surgery?

There are several pain relief methods after surgery:

• Intravenous (IV) or oral pain medications, administered through a vein or taken by mouth, can help alleviate pain, although they may not completely eliminate it. These medications are typically prescribed by the surgeon and are commonly used in the recovery room.

• Femoral nerve blocks, which can be single injections or continuous nerve blocks, are another option to manage post-surgery pain. These blocks involve the use of local anesthetics and other drugs to reduce pain originating from the femoral nerve. The femoral nerve supplies sensation to a significant portion of the front of the knee and a large area of the knee joint. Typically, these blocks provide relief for about 15 hours, but if a nerve catheter is utilized, the relief can last as long as the catheter remains in place.

How Is a Femoral Nerve Block Performed?

A femoral nerve block is done in the following way:

• Sedation: Before the procedure, the patient is sedated to ensure comfort.

• Numbing the Area: The anesthesiologist numbs the skin in the groin area, where the femoral nerve is located.

• Insertion of Needle or Catheter: A specialized needle or catheter is carefully placed near the femoral nerve.

• Local Anesthetic Application: Local anesthetic is injected to surround the nerves, blocking pain signals.

• Extended Pain Control: If needed for more than 15 hours post-surgery, a catheter is inserted by the anesthesiologist to continuously administer pain-relieving medicines.

• Return of Sensation: Once the catheter is removed, the sensation in the thigh gradually returns to normal, typically within a few hours.

• Temporary Numbness and Weakness: The femoral nerve controls feeling in the front of the thigh and the muscles in that area. While the nerve block is active, the front thigh will be numb, and associated muscles will be temporarily weak.

What Are the Potential Risks Associated With a Femoral Block?

Femoral blocks carry certain risks and precautions:

• Complications Monitoring: Complications or side effects are possible and closely monitored. Anesthesiologists employ specific methods to prevent these issues.

• Rare Nerve Injury: Nerve injury after a block is rare, occurring in approximately one in 4,000 to one in 200,000 cases. This can result from direct needle injury or complications like bleeding or infection.

• Communication with Anesthesiologist: It is crucial to inform the anesthesiologist if sharp or radiating pain is experienced during needle placement or injection, as this can help prevent nerve injury.

• Post-Block Symptoms: If new symptoms like tingling, numbness, or motor dysfunction occur after the block wears off, contacting the medical team promptly is essential.

• Risk of Falling: Due to temporary thigh weakness caused by the block, there is a risk of falling. Wearing a knee immobilizer (locked in position) while walking during the block's effectiveness is mandatory. Additionally, assistance should be sought while walking as long as the block is in effect.

Conclusion

In ACL surgery, anesthesia plays a vital role in patient comfort and safety. General and regional options, like femoral nerve blocks, offer tailored pain relief. Post-surgery, a combination of medications and nerve blocks provide varied pain management. Effective communication and awareness of potential complications are crucial. A personalized approach ensures a safe and comfortable recovery for ACL surgery patients.