It is my belief that a modified external incision technique allows maximum control and flexibility in order to achieve the goal of creating an optimal crease. This is based on setting a high benchmark of achieving an ideal crease height, with an appropriate crease shape, continuity of the crease line and permanence of the crease thus created (beyond at least several years).
The steps involved are as follows:
Medications and surgical setup
marking of incision and crease placement
the first vector – beveled surgical plane and opening of orbital septum (Chapter 8)
treatment of fat (continued to Chapter 9 )
the second vector – excision of orbicularis oculi and septum
treatment along superior tarsal border and preaponeurotic space
construction of lid crease
closure of incision.
Pre-Medications and Surgical Setup
The patient usually receives 10 mg of diazepam (Valium) and one Vicodin (acetaminophen and hydrocodone) tablet (5 mg) orally 60 minutes before the procedure. The patient is placed in a supine position and intravenous line and electrocardiographic monitors are applied. A pulse oximeter that provides a real time readout of the patient’s P aO 2 (arterial blood gas) is applied. All patients are given a nasal cannula with 1–2 liters/minute of room air flowing through it.
Anesthetic Mixture and Injections
Two mixtures of local anesthetics are prepared.
First: 1 ml of 2% xylocaine with 1 : 100 000 dilution epinephrine is diluted by 10× with 9 ml of injectable normal saline. This mixture now has a pH closer to neutrality since it has been diluted with the buffering action of injectable normal saline. The epinephrine is now diluted to 1 : 1 000 000. (This is labeled ‘Diluted’.)
Second: 5 ml of 2% lidocaine (Xylocaine) containing 1 : 100 000 dilution of epinephrine is drawn. (This is labeled ‘Full strength’.)
I apply a drop of topical anesthetic, 0.5% proparacaine hydrochloride, on each eye for comfort prior to surgical preparation and draping.
Using a No. 30 or 32 gauge needle, I infiltrate 0.1–0.2 ml of the diluted anesthetic subcutaneously along the superior tarsal border ( Figure 8-1 ). During the next few minutes, anesthesia takes effect and one can observe blanching of the eyelid skin from the powerful vasoconstrictive effect of the diluted epinephrine–anesthetic mix ( Figure 8-2 ).
I then inject the regular strength 2% lidocaine with epinephrine in the suborbicularis plane along the superior tarsal border, usually giving less than 0.5 ml per eyelid.
The purpose of this two-staged injection of local anesthetic is to allow for a relatively painless pre-infiltration to anesthetize the surgical field before the full strength of acidic 2% lidocaine is given. (One may add sodium bicarbonate to the 2% mixture to achieve the same effect.)
When confronted with a patient with low threshold for pain, one may supplement the local field infiltration with a frontal nerve block. A 30 gauge half-inch needle may be used to apply 0.5 ml of the anesthetic into the supraorbital space just lateral to the supraorbital notch. (Frontal nerve infiltration is rarely necessary or performed.) Intravenous sedation or analgesic may be given.
The eyelids and face are then prepared in the usual fashion for surgery. The eyes again receive a drop of topical anesthetic, this time using tetracaine hydrochloride for longer-lasting corneal anesthesia. To eliminate the sensation of claustrophobia that often occurs with full draping over the nostrils and mid-face, nasal delivery of room air through a nasal cannula is used. Opaque black corneal protectors are then applied over each eye.
The use of diluted anesthetic solution helps to:
decrease pain upon injection
decrease volume of anesthetic needed for injection
create less tissue distortion as a result of less volume expansion and lessened bleeding; it allows the surgeon to stay focused on the surgical plane.
The use of nasally delivered room air or low-flow oxygen serves to decrease patient’s sense of claustrophobia.