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Beyond blepharospasm: botulinum can be used in other ocular defects
Botox has applications beyond the traditional treatment of blepharospasm and its recent popularity in plastic surgery.
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| Spastic lower lid entropion: before (top) and after (bottom) botulinum toxin injection. |
SAN DIEGO – Botulinum toxin has other uses beyond blepharospasm and its recently approved cosmetic applications. The drug can also be used to treat hyperlacrimation, spastic entropion, strabismus caused by thyroid eye disease and several other eye conditions, according to a surgeon.
Don O. Kikkawa, MD, of the University of California in San Diego, said he has applied Botox (botulinum neurotoxin A, Allergan) to more eye conditions than most surgeons. He has also used it to treat frontalis hypertonicity and in lid reconstruction. Botox has recently garnered attention with its approval for aesthetic applications, but the uses Dr. Kikkawa described are still considered off-label.
“Botox has been used for the past 2 decades, primarily in the treatment of nonessential blepharospasm, hemifacial spasm, strabismus and cervical dystonia,” Dr Kikkawa said. He said he has used it for the past 10 years.
Two forms
There are two forms of the toxin available for therapeutic use. Botox is botulinum A, one of the most potent naturally occurring toxins, Dr. Kikkawa said. It inhibits the release of acetylcholine at the neuromuscular junction and binds irreversibly for 3 to 4 months, he said. Myobloc (Botulinum B, Elan Pharmaceuticals) is approved only for treatment of cervical dystonia caused by neck torticollis.
“Anecdotally, Myobloc seems a bit more uncomfortable and gives a slight burning sensation during the injection compared to the botulinum A toxin,” Dr. Kikkawa said.
Hyperlacrimation
Dr. Kikkawa described several off-label applications for Botox that have been found useful.
Injections of Botox have been used to treat hyperlacrimation caused by aberrant regeneration of the seventh nerve, he said. Three injections, 2.5 units each, were administered directly into the lacrimal gland. (Each vial of Botox contains 100 units.)
“This inhibits the secretomotor fibers of the seventh nerve and the gustatory lacrimation these patients have,” Dr. Kikkawa said.
Because the levator aponeurosis is close to the lacrimal gland, direct injection into the gland may spill into the levator muscle. As a result, patients may develop a reversible ptosis. Researchers who investigated the use of Botox with this condition reported that two out of three patients developed the reversible ptosis, he said.
Spastic entropion
Patients with spastic entropion who are debilitated but cannot undergo surgery are also candidates for Botox injection, Dr. Kikkawa said. Usually these patients are elderly or have severe systemic disease. He typically administers 20 to 30 units directly into the orbicularis muscle to temporarily cure the entropion.
“What I’ve done with these cases is give them a Botox injection directly into the lower eyelid to give them temporary relief,” he said.
Strabismus
Dr. Kikkawa has also used Botox as an adjunct treatment for strabismus of thyroid eye disease. In patients with large muscles with Graves’ disease, he uses Botox to prevent contraction of the medial rectus muscle.
“In Graves’ patients when we perform orbital decompression, we notice that particularly in large medial rectus muscles, if you perform a medial wall decompression you’re going to be opening up the ethmoid sinus. The muscle will then prolapse into the sinus and contract,” he said. “We’ve been using Botox as an adjunct to try to prevent that contraction.”
Frontalis hypertonicity
Dr. Kikkawa has also found Botox useful to stop muscles from continuing to compensate after ptosis is corrected. He discussed the case of a patient with ptosis of the eyelid. After surgery to correct the ptosis, her frontalis muscle continued to compensate for the prolapsed eyelid. In such cases, he said he injects Botox into the muscle to bring the eyelid down.
“We injected the frontalis muscle and brought her eyelid down. This is kind of a habitual reflex that patients have,” he said. “By and large, once you inject them in the office, that frontalis reflex for the ptosis will disappear,” he said.
Rhytids
Aesthetic uses of Botox include treatment of rhytids, Dr. Kikkawa said. The primary periocular uses are in the forehead and the glabellar region and for crows’ feet.
“Botulinum toxin really only works for the dynamic rhytids, the ones that occur from facial muscle contractions,” Dr. Kikkawa said. The muscles that are usually targeted are the frontalis muscle, the corrugator and procerus muscles in the glabella and the orbicularis oculi around the eyelid.
Glabellar injections are the most common. Forehead injections are less common. Ophthalmologists should be aware that the frontalis muscle is often being used to compensate for ptosis, he said, and Botox injections may actually worsen brow ptosis.
The dosage is generally high for forehead injections, intermediate for glabellar injections and minimal in the orbicularis area, he said. Because Botox has no preservative, there is a 4-hour window in which it can be used.
Lid reconstruction
Dr. Kikkawa sometimes uses Botox preventively in lid reconstruction to immobilize the eyelids for several weeks after placement of skin grafts. Injection of Botox can help prevent blinking too soon after surgery.
“If the patient begins to blink soon after surgery, the graft can become hypertrophic and may even slough off,” he said. “If you can treat acutely with Botox to give you a couple of weeks of immobilization, the healing of the skin grafts seems to be improved.”
Contraindications
Recent publications have expressed concern about the use of botulinum toxins because they are pooled human albumin products that have a theoretical risk of prion transmission. However, Dr. Kikkawa said, there have been no reports of virus transmission from the use of plasma-derived products, he said.
Patients who are pregnant, nursing or have allergy to botulinum toxins or albumin should not be treated with Botox, he noted.
For Your Information:
- Don O. Kikkawa, MD, is director of oculoplastics at the Universtiy of California, San Diego. He can be reached at Shiley Eye Center, 9415 Campus Point Drive, LaJolla, CA 92093-0946; (858) 534-7402; fax: (858) 534-7859; e-mail: dkikkawa@ucsd.edu. Ocular Surgery News could not confirm whether Dr. Kikkawa has a direct financial interest in any of the products mentioned in this article or if he is a paid consultant for any company mentioned.
- Allergan, makers of Botox, can be reached at 2525 Dupont Drive, Irvine, CA 92612; (800) 366-6554; fax: (800) 752-7006.