fbpx

Crow’s Feet

Anatomy

Eyelid skin is thin and elastic, with no underlying subcutaneous fat. Orbicularis oculi, is an elliptical muscle that closes the eyelids and acts as the sphincter of the eye. Orbicularis oculi has three parts: orbital, palpebral and lacrimal. The lacrimal part connects to the lacrimal sac and inserts on the upper and lower eyelids at the tarsal plate. The palpebral part is the innermost aspect of the muscle and provides the less forceful closure of the eyelid, such as a blink. The orbital part is outermost aspect of the muscle and blends into the surrounding muscles. This is part that accounts for the forceful closure of the eyelids and pulls the skin. Zygomaticus minor typically lies deep to the orbicularis oculi from the zygomatic bone. Therefore, a deep injection should be avoided here. Dysport (an off-label use) can be injected into the orbicularis oculi for treatment of crow’s feet.

Evaluation

The lateral portion of the orbicularis oculi lies in a vertical direction. Researchers have identified up to 4 different lateral canthal rhytid patterns. A standard injection points are taught to beginners, but in some instances, treatment may require individualization. Evaluate the crow’s feet by asking the patient to squint. Note any asymmetry, lid ptosis, brow ptosis, scleral show or lid laxity. Most importantly, use bright light and stretch the skin to find any fine vessels coursing through this region and mark them to avoid an injection into them.

If you feel that your ideal injection mark is immediately over a vessel, then place you injection lateral to the vessel. Also we recommend that you mark the palpable lateral orbital rim. This will aid in ensuring that your injection is placed outside of the boney rim. Finally, discuss with your patients other adjunctive treatment options such as various skin tightening modalities to improve patient satisfaction.

Injection Technique

Stand in a position so that the needle is pointed away from the eye (inject superiorly, needle pointing up to the ceiling). You may use your noninjecting finger to shield the globe by placing your index finger in the lateral orbital groove or stretch the skin to aid in the penetration of the skin. Injections should be superficial dermal injections(2 – 3 mm deep) resulting in a wheel formation. Injections are also commonly 1.5cm from the lateral canthus or 1cm lateral to the boney orbital rim. Dysport is injected 1 to 1.5 cm apart in an arc-like pattern using 8 units per injection. Place your middle injection lateral in-line with the lateral canthus.

Adverse Events

Similar adverse events such as pain and swelling can occur. Rate of ecchymoses can be high at 25%. This can be avoided by injecting around a vessel, superficially with only the tip of the needle in the skin. Pressure should be applied immediately for up to 5 minutes to reduce the risk of a hematoma. Lip ptosis can rarely occur due to involvement of the lip elevator muscles that blend with the orbicularis oculi muscle.

The rate of this complication is less than 1%, and is due to deeply or inferiorly placed injections. No treatment is available, but it is reported that the muscle normalizes within 6 weeks. Some patients may notice a new wrinkle beneath the eye or along the malar prominence, especially when smiling. This may be due to the contraction of the zygomaticus muscles and elevation of the cheek. Eyelid and eyebrow ptosis can occur if the injection diffuses into muscles above the orbital rim.

Treatment Failure

Treatment failure can be differentiated into Primary and Secondary nonresponders.

Primary nonresponders are first time Dysport® users;

  • A major reason for this is due to the fact that wrinkles are not dynamic in origin (usually due to photodamage or age-related). These wrinkles had a static component to them that required the injection of a filler material.
  • Injection amount may have been inadequate. This is like due to either the patient has strong muscles or your injection missed the targeted muscle.
  • Toxin had denatured. Rarely, you will get a bad vial of Dysport. In this case contact your representative for replacement vial.

Secondary nonresponders

These patients initially responded to Dysport® but lose the response on subsequent injections;

  • Injection amount was inadequate. This is like due to either the patient has strong muscles or your injection missed the targeted muscle.
  • Toxin had denatured.
  • Your patient may have developed neutralizing antibodies. This is a rare, but a side effect. You may find success in using a different Botulinum Toxin such as Myobloc on these patients.

Conclusion

  • Use your hands. Feel the face. Inject where you can feel the muscle that causes the visible wrinkles.
  • Always inject a relaxed face, not a face where the muscle is contracted. A contracted face distorts your landmarks and increases pain.
  • Use a marking pen or a white eyeliner pencil for marking your injection site until you become proficient. Place the marks below where you will inject. Or, your injection should be above the mark. Injecting into a mark on the face can cause a tattoo on somebody.
  • Remember that many landmarks are BONEY landmarks. Do not simply use surface skin landmarks as your reference.
  • All complications may be seen immediately or as late as 7 days. Complication may persist for up to 4 – 8 weeks.
  • Most complications are almost always temporary. In your practice, you are likely to experience a complication. Be prepared for it. Good customer service and patient reassurance that the complication is temporary will appease most patients.
  • ALWAYS obtain before photos and after photos. This is an essential documentation to have to resolve any complaints.
  • Reinjection should be done no earlier than one week after the first injection if the patient perceives no desire effect. Sometimes, it takes a week until a patient sees the effects.
  • Application of topical EMLA anesthetic or cold ice pack will help alleviate patient discomfort and injection fears.
  • Please become familiar with the Pre and Post injection instructions. Your patients will ask you about them. Also, your patient’s compliance with them will reduce complications.
  • Most importantly, be conservative. You can always inject more Dysport. But, you can’t take it out.

Restylane® / Perlane®

Learn more about Restylane® / Perlane®.