Overview of Anesthetic Considerations in Hemifacial Microsomia
Hemifacial microsomia is a condition where one side of the face doesn’t grow properly in a baby before birth. Occasionally, both sides might not develop fully. Some babies with this condition may only look slightly different, while others may have extreme differences in facial features, to the point where they might have difficulty breathing. In severe cases, a surgical procedure known as a tracheostomy may be required early in life. This procedure creates an opening in the neck to allow the person to breathe.
This condition is the second most common birth defect affecting the head and neck, coming after cleft lip and cleft palate. It occurs roughly in 1 in every 3500 to 4000 births. Conditions within hemifacial microsomia can vary greatly, leading to many categories of the condition. A common way to categorize it includes the O.M.E.N.S. classification, which grades the severity of the condition’s impact on the eye sockets, lower jaw, ears, facial nerves, and soft tissue.
Another system, the Pruzansky and Kaban classification, is used to assess the jaw’s condition, aiding in deciding the necessary surgical interventions. Most patients with hemifacial microsomia have issues with their ears, both in appearance and function, often leading to impaired hearing that needs surgical treatment.
In rare instances, hemifacial microsomia can affect both sides of the face, resulting in serious facial deformities and growth problems. There have also been rare cases reported where other internal organs might be impacted, emphasizing the need for thorough medical examinations in severe cases to rule out further complications.
Understanding the causes and progression of hemifacial microsomia is important for predicting potential surgical and anesthesia challenges, especially those regarding airway management. A study in 2020 reviewed the anesthetic management of 311 children with hemifacial microsomia. The study found that all but one child could be anaesthetized using a facemask. Video laryngoscopy and fiberoptic techniques had a 100% success rate for intubation, whereas the success rate of direct laryngoscopy was lower at 79.5%. The findings suggest these cases should be approached as if they could present challenges with airway management.
Anatomy and Physiology of Anesthetic Considerations in Hemifacial Microsomia
Hemifacial microsomia is a condition that happens due to injury or problems with blood flow to particular structures, called brachial or pharyngeal arches, while a baby is developing. This problem usually happens around the fourth week of pregnancy. Although we might expect a genetic link, no research has confirmed this just yet.
These brachial arches, while you’re an embryo, have a crucial role in shaping certain parts of the face and neck. The first arch, also known as the mandibular arch, helps form the upper jaw, lower jaw, chewing muscles, and parts of the middle ear.
The second arch, also known as the hyoid arch, helps form the neck and many other structures between your head and neck. This arch is also connected to a nerve that helps control the muscles used for facial expressions.
If a baby has hemifacial microsomia, this will mean parts like the lower jaw, the joint that lets the jaw open and close, and the neck may not grow properly or be underdeveloped. This could make administering anesthesia, which is a medicine used to prevent pain during surgery, more challenging. It’s essential that the doctors understand these potential issues to provide the best possible care.
Why do People Need Anesthetic Considerations in Hemifacial Microsomia
Some severe health issues can make it difficult for a person to breathe as soon as they are born. In these rare cases, doctors may need to perform surgery to create an opening in the windpipe, a procedure called a tracheostomy. This allows the person to breathe more easily. This is a complex process that requires careful planning and coordination between experts in children’s anesthesia and specialized surgeons.
People with certain types of health issues may need to undergo several surgeries as they grow older. These surgeries depend on the specific problems they have. Typically, doctors like to wait until a person’s face and tissues are fully grown before doing any surgical procedures.
For starters, if a child has problems with their ears, doctors can do surgery to reconstruct the external part around the age of 7, since the ears are usually fully developed by then.
If the temporomandibular joint, which is the joint that connects the jaw to the skull, does not develop properly, there may be need for surgery between the ages of 6 and 12. This surgery usually involves taking a piece of rib and placing it into the jaw to help it grow and develop, a process known as a costochondral graft. Other times, they may use an approach called distraction osteogenesis, which involves inserting special devices that can be gradually expanded to lengthen the bones.
Most major surgeries are usually done when a person’s bones are fully grown. This is typically between the ages of 16 and 20. It’s very important to get the timing right for these surgeries. If a surgery to correct a facial issue is done too soon, before the person has stopped growing, it could result in complications. In these major surgeries, the jaw, cheekbone, and other bones in the face might need to be cut and moved, sometimes even replaced.
When a Person Should Avoid Anesthetic Considerations in Hemifacial Microsomia
Except for urgent breathing problems, surgeries for these patients are usually not immediately necessary and can be planned accordingly. There are certain conditions where it’s better to wait before performing surgery.
Firstly, if a patient’s general health is unstable due to other illnesses, surgery should be delayed until their health improves. Furthermore, if a patient has an active infection, sepsis (a severe infection that can spread through the whole body), or their body is struggling to maintain its normal balance due to other health issues, it’s better to delay the surgery.
Similarly, if the patient has other urgent surgical needs, the decision to delay the operation should be made after a detailed discussion among different medical experts. Hence, a comprehensive discussion between different medical departments is important to decide the right time for surgery.
Equipment used for Anesthetic Considerations in Hemifacial Microsomia
For a surgery, the operating room will have a basic setup, which includes an anesthesia machine that can help you breathe and give you gas to keep you asleep. There will be different types of monitors and machines to track your heart rate, blood pressure, how well your body is using oxygen (pulse oximetry), your heartbeat pattern (EKG) and your body temperature. There will also be a cart or storage box with various medicines and supplies for things like inserting a drip (IV lines), bandages, and other needs.
Depending on the surgery and the surgeon’s choice, there will be different equipment ready to help secure your airway (the path that air follows to get into and out of the lungs). This could include various sizes of both mouth and nose tubes, different tools (Mac or Miller blades) for viewing and accessing the throat, a video system for viewing the throat (laryngoscope), and special tweezers (Magill forceps) if a tube needs to be inserted through the nose. They usually have a fiberoptic scope on hand as a backup in case there are difficulties with the airway.
If the team decides to use nasal intubation (putting a tube through the nose), they will gradually increase the size of the airway with nasopharyngeal tubes or use a flexible tube (red rubber catheter). A nasal spray (Afrin) and lubricant may also be used. Depending on the length and complexity of the surgery, and expected blood loss, they may decide to monitor your blood pressure directly from an artery, prepare a second IV line just in case it’s needed, insert a tube (foley catheter) to drain the bladder, and control your body temperature with a warming blanket or system.
Who is needed to perform Anesthetic Considerations in Hemifacial Microsomia?
When a patient is undergoing anesthesia, specially trained doctors known as anesthesiologists are present. If the patient is a child, it might be best to have a pediatric anesthesiologist involved, who specializes in providing anesthesia to children. As the process of placing a tube in the throat to assist breathing, known as intubation, can sometimes be tricky, it is usually best to have two or three anesthesiologists present.
It’s also vital that the surgeon and their team are ready during intubation. They should be prepared to step in and assist with any surgical needs, based on what they know about the patient’s airway and breathe related matters. In addition to the surgical team and anesthesiologists, the usual operating room staff are also there such as the operating room nurse and surgical assistants.
Preparing for Anesthetic Considerations in Hemifacial Microsomia
Before the surgery of patients with hemifacial microsomia – a condition where one side of the face is underdeveloped compared to the other – certain key steps need to be taken. This includes a detailed check-up, noting measures like the largest space the patient can open their mouth, the distance from the thyroid to the chin, and other observations that connect to the patient’s condition.
Doctors need to have a plan and a backup plan should the airway – the path that air takes to get in and out of the lungs – become difficult to manage during surgery. Most of the face surgeries need a procedure called nasal intubation, where a flexible tube is inserted through the nostrils into the windpipe. Doctors need to make sure that the tube is the right size and length, and it is placed correctly.
To help with nasal intubation, certain tools, like a special video device, are used. This video device offers a clear view of the tube’s placement and reduces the chances of a mistake. If the patient has an underdeveloped jaw or neck, an awake nasal intubation, which is done while the patient is awake, may be considered. This also involves the application of drugs to numb the airway.
Some surgeries may turn out to be more complicated than anticipated. For these situations, the team needs to be prepared to address the issue of not being able to insert the tube or help the patient breathe, with all the necessary tools and a surgeon ready to step in.
Standard checks including machine operation, airway equipment, ventilation equipment, and making available necessary drugs, are all part of the preparation. Depending on the nature of the surgery, tests like blood and clotting tests might be considered.
After the surgery, the key decision is when to remove the tube from the patient. Normally, despite the surgery involving the head and neck, there is minimal swelling in the airway. The timing of the surgery is also taken into account. If the surgery is long and ends late, then it would be safe to consider leaving the tube in overnight and evaluate the patient the next morning.
Lastly, the treatment might require wiring the patient’s jaw together at the end of the surgery. This largely depends on how the surgery goes. If this does happen, the patient may also have restrictive bands at the end of the surgery. It is crucial for the anesthesia and surgical teams to discuss this possibility thoroughly.
How is Anesthetic Considerations in Hemifacial Microsomia performed
Two main procedures used in this process are nasal intubation, where a tube is inserted through the nose to help with breathing, and tackling challenges in managing the airway, which is our breathing passage. These steps can sometimes be tricky to perform.
The use of anesthesia, which is medicine to help with pain and make you sleep during the surgery, is standard. It can be administered either as a gas that you breathe in, or a drug given through the veins, based on what the doctor and surgeon think is best for you.
Possible Complications of Anesthetic Considerations in Hemifacial Microsomia
One of the main risks linked with using anesthesia for this type of patient is facing a situation where doctors can’t insert a breathing tube and can’t properly ventilate the patient’s airway. This is an issue we refer to as “cannot intubate cannot ventilate,” and it could require a surgical procedure to secure the airway. But, with careful planning and preparation, doctors can often avoid this problem.
What Else Should I Know About Anesthetic Considerations in Hemifacial Microsomia?
Having this kind of deformity can cause issues with the growth and functionality of several parts of the face and jaw, like the maxilla (upper jaw), mandible (lower jaw), and the temporomandibular joint (joint that connects the jaw to the skull). It can also greatly impact the airway, or the passage through which air enters and exits the lungs.
In light of these potential problems, it’s really important for every part of the patient’s condition to be thoroughly examined and taken into account while planning and managing anesthesia. This way, any risks or problems can be anticipated and handled appropriately, ensuring the best care for the patient.
