Botulinum toxin safety enhanced with careful injection technique

September 1, 2004

New York - Meticulous attention to technique is probably the most important rule for avoiding complications when treating patients with botulinum toxin for cosmetic indications, says Neil S. Sadick, M.D.

New York - Meticulous attention to technique is probably the most important rule for avoiding complications when treating patients with botulinum toxin for cosmetic indications, says Neil S. Sadick, M.D.

"Botulinum toxin can be remarkably safe, but it can also be associated with a number of complications, the most common of which are all technique-related. However, adapting injection patterns based on an understanding of the relevant musculature and appreciation of the individual's anatomy will enable attainment of the desired cosmetic results with minimal risk," says Dr. Sadick, clinical professor of dermatology, Weill Medical College of Cornell University, New York.

In addition, the toxin should be delivered with a two-handed traction technique using a fine, hort, sharp needle. Dr. Sadick notes he uses an Ultra-Fine II 0.3 cc insulin syringe with a 30-gauge needle that he changes every three to four injections.

Minimizing the number of injections, and, when treating crow's feet, inspecting the area for blood vessels to avoid direct injection are other helpful measures to reduce the development of bruising. In addition, it is worthwhile to take a careful medication history and to have patients discontinue use of agents that can affect coagulation, he says.

"Ask about use of aspirin and NSAIDs, but don't forget to query patients about vitamin E and herbal preparations that they might not consider as medications," Dr. Sadick says.

Correct toxin placement is the solution to avoiding two other complications of botulinum toxin injection - brow and lid ptosis. To avoid brow ptosis, the area lying 1 cm above the brow should be considered a "no injection" zone. In addition, overtreatment of the frontalis should also be avoided, as should any frontalis injections in persons over the age of 60 who have loose, redundant eyelid skin and tend to use that muscle for elevating the brow in order to achieve accurate vision. Males also appear to be at increased risk for developing brow ptosis and so should be treated with caution.

Overtreatment of the levator muscle is the cause for lid ptosis, and the risk for that occurrence is increased when delivering the toxin below the level of the orbital rim. Staying away from the orbital rim is also important for avoiding diploplia, which arises from inadvertent injection into the extraocular muscles, says Dr. Sadick.

To avoid causing lid ptosis, Dr. Sadick reminds surgeons not to use a downward injection technique and suggests pressing lightly with a fingertip against the medial to superior orbital rim while delivering the injection.

"Presence of the finger prevents delivery of the toxin too inferiorly, as well as its migration once it is injected," Dr. Sadick explains.

If eyelid drooping occurs, it is self-limiting, resolving within two to 12 weeks, and it usually can be effectively managed in the interim with instillation of apraclonidine, one to two drops three times a day.

Brow contour irregularities are another technique-related pitfall that can arise when treating the frontalis if its most lateral fibers are not injected. To avoid that problem, the operator needs to assess how far laterally the frontalis extends. That can be done by palpating the muscle while the patient contracts the forehead to lift the brows.

As a general measure, Dr. Sadick advocates reconstituting the vials of botulinum toxin with 2 mL of preservative-free saline to achieve a final botulinum toxin concentration of 5U/0.1mL.

Disclosure: Dr. Sadick is a consultant to Allergan, manufacturer of botulinum toxin type A (Botox, Botox Cosmetic) and Elan, manufacturer of botulinum toxin type B (Myobloc).