Surgical removal of the eyelid and brow-squeezing muscles is referred to as a myectomy procedure and is used to treat blepharospasm. Myectomy prevents the muscles surrounding the eyes from being stimulated by removing the muscle.
Before the availability of botulinum neurotoxin, myectomy was essentially the only treatment option for blepharospasm. The introduction of botulinum toxin injections in 1989 benefited many persons with blepharospasm thereby changing the population of individuals eligible for myectomy. Candidates for myectomy became those for whom botulinum toxin is not sufficient.
Just as the patient selection changed, the procedure itself evolved. Initially, the procedure involved removing all eyelid-squeezing muscles in both upper and lower lids as well as the brow area at one time. At the present time, the procedure is tailored to the needs of the patients. It is most common for the surgeon to remove the muscle in the upper eyelids and brow (full upper myectomy) and then re-evaluate the need for a lower myectomy at a later date. Patients heal faster when the procedure is done in stages, and some individuals do not require the lower myectomy.
The full upper myectomy may be done entirely through an eyebrow incision. The incision lies immediately adjacent to the brow hair and allows access to the upper lid orbicularis muscle, and part of the lower lid orbicularis muscle as well as the procerus and corrugator muscles in the brow area. Most of the orbicularis muscle is removed during the eyelid surgery. A strip of dense muscle is left at the margin of the upper eyelid to help maintain some voluntary closure and to protect the eyelash roots.
A limited upper myectomy is a partial upper myectomy. It is available for those individuals who are benefiting from botulinum toxin but need something extra to restore function of the eyes. It may be helpful for those patients who have apraxia (difficulty opening the eyes) or for those who in addition to blepharospasm have ptosis (drooping lids). Partial removal of the orbicularis may subsequently decrease the need for botulinum toxin in these patients. A limited myectomy is done through an upper eyelid crease incision and involves removal of the orbicularis muscle within the upper lid area only. Because there is less tissue removal than the full upper myectomy, patients recover in less time. A limited myectomy also gives more predictable cosmetic improvement because less tissue is removed. It is not designed to replace a full upper myectomy. Most patients will still require botulinum toxin injections following the limited myectomy procedure.
Persons who have stopped responding to botulinum toxin as well as those rare individuals who fail to respond at all may be eligible for myectomy. Individual surgical centers have treated hundreds of blepharospasm patients with myectomy. Techniques used for cosmetic surgery, such as sculpting the fat beneath the brow and manipulating the placement of the brow, may be implemented to provide a beneficial aesthetic as well as functional result.
Myectomy surgery can be done under local or general anesthesia. The healing process following a myectomy may take up to a year. In most cases, the patients are able to keep their eyes open immediately following the operation. However, considerable swelling, hematomas (blood accumulation in lid), lymphedema (tissue fluid), and bruising may be present early in the post-operative period and prevent complete eyelid opening. Cool compresses in the first four to five days followed by warm compresses are very helpful at settling the lid swelling and bruising.
There are numerous potential side effects associated with myectomy surgery that are predictable and, to some degree, occur in most patients. Numbness of the forehead region often occurs and is usually temporary but may last a year or more. Loss of tissue volume in the eyelid area may occur with the muscle removal, but the improved brow, lid position, and decreased eyelid wrinkling generally gives an improved cosmetic appearance. Decreased eyelid closure occurs as a result of eyelid muscle removal and may require the need for additional artificial tears and lubricating ointment. As the eyelid swelling resolves, the eyelid closure improves and the dry eye symptoms generally improve. Chronic lid swelling which may last six months or longer in some patients can be a chronic and troublesome complication. Chronic lid selling is much less severe and persistent in the modern myectomy practices in which upper and lower lid myectomies are performed separately. Infection, hematoma, brow hair loss, and abnormal positioning of the lower lid can occasionally occur but are uncommon.
Patients continue to improve in function as well as in appearance for about six months to a year after myectomy surgery. Reports have shown that visual disability is improved in approximately 90% of patients. Some patients have more improvement than others. Touch-up procedures are required in some cases, and some individuals continue to require botulinum toxin injections.
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