STAGE 1

Stage 1 AVMs typically are not problematic unless they cause a deformity and affect the patient’s self-esteem. Localized lesions should be removed before they progress to a higher-stage AVM. Resection of a stage 1 AVM gives the lowest recurrence rate and best chance for long-term control or cure. Localized lesions are most likely to be removed completely with the least morbidity. Waiting until the lesion expands complicates the resection and reconstruction and increases the likelihood of an unfavorable long-term outcome. If a localized lesion involves an anatomically unfavorable area (for example, the tip of the nose or upper eyelid) that would require complicated reconstruction, leaving a worse deformity than the lesion, I recommend waiting until the AVM worsens and becomes symptomatic in the future. Approximately 16% of stage 1 lesions do not progress long term.

Resection of a regional or diffuse stage 1 AVM should be based on its size and location. Because the entire lesion can rarely be removed, surgical intervention for large asymptomatic lesions is less common. However, if it is possible to completely resect the AVM in an anatomically favorable area (for example, the trunk), prophylactic excision and reconstruction should be considered before the lesion progresses. In contrast, if a large AVM is located on the face and extirpation and reconstruction would leave a significant deformity, it is generally best to wait until the lesion becomes problematic before intervention.

STAGE 2

Stage 2 AVMs are managed similar to stage 1 lesions. However, there is a lower threshold to intervene because the AVM is growing. Stage 2 lesions are more likely to be symptomatic, because they are enlarging. Pulsations from the lesion can also be bothersome to the patient.

STAGES 3 AND 4

Stage 3 or 4 AVMs require treatment for deformity, bleeding, pain, ulceration, and/or congestive heart failure.

TIMING OF INTERVENTION

Stage 3 and 4 AVMs require immediate treatment, regardless of the age of the patient. Milestones for resection of stage 1 and 2 AVMs are: (1) 6 months, (2) 3 years, and (3) late childhood/early adolescence. Generally an AVM should not be removed before 6 months of age. At this time the patient’s risk from anesthesia is greater than for an adult. In addition, a young infant is less able to tolerate a surgical procedure. If a large lesion is located on the scalp, removing it before 6 months of age should be considered to take advantage of scalp laxity that exists during infancy.

if it is likely that a patient will require surgery, a common time I will intervene is between 3 and 4 years of age. Because long-term memory and self-esteem begin to form at approximately 4 years of age, removing an AVM at this time will improve a deformity before the child’s self-esteem begins to form, and the patient will likely not remember the procedure. Another period to intervene is during late childhood/early adolescence when the child is able to communicate whether he/she would like the procedure. if a patient has a minor deformity or a large lesion requiring significant reconstruction, it is often best to wait until the child verbalizes that he or she wants surgery. If the lesion is minor, it may be able to be removed under local anesthesia by waiting until the child is older. If the lesion is significant, then waiting until the child can be a willing participant facilitates the process for the family and surgeon. The surgical strategy for AVMs is based on the extent of the lesion.

LOCALIZED AVMS

A localized AVM involves one to two tissue planes (for example, the skin and subcutaneous tissue), is well defined, and theoretically is able to be entirely removed with linear closure. Unfortunately, these are the least common types of AVMs. Generally, I remove localized AVMs without preoperative embolization, because bleeding is not significant after the area is infiltrated with a local anesthetic containing epinephrine. Avoiding embolization reduces overall treatment morbidity for the patient. If the volume of local anesthetic with epinephrine is limited by the amount of anesthetic that can be given based on the weight of the child, I will infiltrate an epinephrine-only solution to ensure maximum vasoconstriction of the surgical site (1 cc of 1:1000 epinephrine in 200 cc of normal saline = 1:200,000 solution).

Lesions located in anatomically sensitive areas (for example, the face) should have minimal or no margins taken. An AVM is not a malignancy, and evidence does not show that a significant resection margin lowers the recurrence rate. An AVM often involves a larger area than is appreciated clinically and radiographically. Findings of biopsies taken outside of the lesion have shown abnormalities. In my experience if microscopic disease is left after a localized AVM is removed, the recurrence rate is very low. Cautery during the procedure and fibrosis may destroy residual AVM tissue. If a lesion is located in a nonsensitive area (for example, the abdomen), larger margins can be taken as long as they do not complicate the extirpation and reconstruction (see Video 10-1, Arteriovenous Malformation).