Browse the corpus

Hemifacial microsomia is the second most common congenital defect of the head and neck, second only to cleft lip/cleft palate, with an incidence of 1 in 3500 to 1 in 4000. This activity explains and describes the considerations for a general anesthetic in patients diagnosed with hemifacial microsomia undergoing surgical procedures in the operating room setting. Objectives: Describe the pathophysiology of hemifacial microsomia. Review the classification and stratification of hemifacial microsomia. Outline the anesthetic considerations based on the extent of the disease. Summarize peri-operative considerations taken by the interprofessional team for hemifacial microsomia. Access free multiple choice questions on this topic.

Hemifacial microsomia is a continuum of congenital deformities involving genetic disruption of the first and second branchial arches.[1] There are many disorders and syndromes linked to hemifacial microsomia. However, the basic theme of the issue is one side of the face being underdeveloped (in rare cases, both sides can be affected). With the spectrum of disease, this can manifest as a slight deviation all the way up to extremely underdeveloped and noticeable, even resulting in severe airway compromise requiring a tracheostomy early in life.[2] Hemifacial microsomia is the second most common birth defect of the head and neck, second only to cleft lip/cleft palate, with an incidence of 1:3500 to 1:4000.[3] Due to the significant variability and spectrum of the disease, there are numerous and confusing classifications. Generally, they are characterized by the O.M.E.N.S. classification; orbital, mandibular, ear, facial nerve, soft tissue, with each item given a score of zero to three depending on the severity.[4] The Pruzanksky and Kaban classification is commonly used to assess the mandible and is broken down into three grades with several subtypes that help delineate the recommended surgical interventions needed.[3] These patients also often manifest with auricular issues, both cosmetically and functionally, with impaired hearing that requires surgical intervention. Though more uncommon, this process can be bilateral, resulting in marked facial issues and failure to develop. Also rare but reported is other internal organ systems being affected, making a comprehensive medical workup necessary in severe cases to rule out further issues.[5]

Hemifacial microsomia is the second most common birth defect of the head and neck, second only to cleft lip/cleft palate, with an incidence of 1:3500 to 1:4000.[3] Due to the significant variability and spectrum of the disease, there are numerous and confusing classifications. Generally, they are characterized by the O.M.E.N.S. classification; orbital, mandibular, ear, facial nerve, soft tissue, with each item given a score of zero to three depending on the severity.[4] The Pruzanksky and Kaban classification is commonly used to assess the mandible and is broken down into three grades with several subtypes that help delineate the recommended surgical interventions needed.[3] These patients also often manifest with auricular issues, both cosmetically and functionally, with impaired hearing that requires surgical intervention. Though more uncommon, this process can be bilateral, resulting in marked facial issues and failure to develop. Also rare but reported is other internal organ systems being affected, making a comprehensive medical workup necessary in severe cases to rule out further issues.[5] It is critical to understand the pathogenesis of hemifacial microsomia to understand the surgical therapies (generally) and what will be asked of the anesthesia team to best anticipate potential issues and difficulties, especially with airway concerns. A 2020 retrospective review looked at the anesthetic management of 311 hemifacial microsomia pediatric cases to better elucidate these issues. They found that facemask was possible for all except one child, a bilateral case, that required a two-handed mask technique. The success of intubation with video laryngoscopy and fiberoptic techniques was 100%, but the success of direct laryngoscopy was only 79.5%.[6] This illustrates the need to treat these cases as difficult airways and prepare accordingly.

The main complication associated with anesthesia on this type of patient is getting into a cannot intubate cannot ventilate pathway on the difficult airway algorithm necessitating a surgical airway.[32] This can be avoided with meticulous planning and preparation.

The most important part about performing an anesthetic on a hemifacial microsomia patient is the preparation. A discussion with the surgical staff before the day of surgery can be extremely helpful in conveying the anatomic variations and potential airway difficulties. The surgeons can give input on potential airway issues, what they are doing, the length of time and estimated blood loss, any potential surgical issues or considerations, their pre-operative assessment, anticipated post-operative care, and maxillomandibular fixation or elastics. The anesthesia team can discuss their concerns and thoughts on the airway and plans for managing the difficult airway, labs, intraoperative anesthetic and drugs, and other considerations. The nursing staff and techs should be brought on board during a team steps huddle with verification of equipment and a comprehensive case review.