External Incision Methods: 切开法

A survey of the various papers in the literature on the external incision approach reveals that there is a wide variation in techniques and preferences when it comes to whether skin and orbicularis are routinely removed after making the skin incision. Likewise, some surgeons prefer to open the orbital septum and remove a variable amount of preaponeurotic fat.

There are other proponents for smaller skin incisions (or partial incision) only, and further differentiations in the way crease fixations are carried out including skin–levator aponeurosis–skin, inferior orbicularis–levator fixation, septodermal fixation as well as skin–tarsus–skin fixation. Each variant has its own set of pros and cons that need to be considered according to the technical skills, aesthetic sense and level of effort it involves, as well as the patient’s comfort level and acceptance. For example: the skin incision and skin excision school favors making an incision to accurately define the placement of the crease. These practitioners are comfortable with these techniques and with the subsequent wound healing process, and are likely to be less concerned about immediately obvious results. Those who open the orbital septum routinely are likewise comfortable with the anatomic landmarks and aim to clear the preaponeurotic zone along the superior tarsal border. Overall, the external incision surgeons feel more comfortable with the predictability and permanence of this approach, which aims for a longer-lasting crease form and less need for interval adjustment surgeries. This approach, especially when carried out without the need for placement of buried sutures, frequently yields a crease form that is subjectively comfortable for the patient on upgaze and downgaze, without the often-heard complaint of tightness of the upper lid and sensation of the buried sutures poking at the pretarsal zone. The partial-incisional methods surgeons, who tend to make a limited 5–8-mm incision, try to accomplish the debulking of soft tissues through a smaller incision than a full incision, although the wound often appears much wider than published. One drawback may be a crease form that appears deeply formed over the central skin incision compared with the medial and lateral edge.

DYNAMIC VERSUS STATIC

The concept of a “dynamic” versus a “static” crease is worth elaborating upon; in a patient who has a natural crease, whether an Asian or a Caucasian, the upper eyelid shows a crease that is well defined when the subject is looking straight ahead ( Figure 5-1A ). On downgaze, the inferior rectus (and superior oblique) of the globe contracts while the superior rectus, levator and inferior oblique all relax. The upper lid follows the inferior rotation of the eyeball and the upper lid crease becomes much less prominent, sometimes becoming barely observable (see Figure 5-1B ). A crease that is present when the levator contracts and fades when the levator relaxes on downgaze is termed a “dynamic” crease. A surgically applied crease that is present and noticeable even on downgaze (when the levator is relaxing) is termed a “static” crease.

CONSTRUCTION OF THE UPPER EYELID CREASE

In terms of crease construction techniques, a wide variety have been published, some with minor differences. The prevalent ways to fashion a well-formed crease can be categorized simplistically as those connecting:

Option 1 : S kin to levator aponeurosis (or tarsus), and back to skin.
Option 2 : Inferior subcutaneous (soft tissues including orbicularis oculi) to levator aponeurosis (or tarsus).

Option 1(A): Skin-to-Levator Approach

In this first technique, which is favored by the author, the sutures are placed such that they first bite the inferior skin edge ( Figure 5-2 ), then the distal fibers of the levator aponeurosis, precisely and partial thickness only, along the superior tarsal border, and then the upper skin edge. This creates an attachment between the levator aponeurosis and the subdermal area along the superior tarsal border, mimicking the natural insertion of the levator aponeurosis. Fernandez described this technique in 1960 and stated that it gives a “dynamic and superficial crease” ( Figure 5-3 ), as opposed to skin–tarsus–skin (Option 1(B) below), which attaches both skin edges to intratarsal tissues right along the superior tarsal border and tends to yield a “static” crease ( Figure 5-4 A, B ).

Option 1(B): Skin-to-Tarsus Approach (see Figure 5.4 )

In this option 1 (B), the skin along the wound edges are attached to intratarsal tissue right along the superior tarsal border and tends to yield a “static’ crease (see the 1954 paper by Sayoc ; Figure 5-4 ).

Option 2(A): Inferior Subcutaneous Plane to Levator Aponeurosis

In Option 2(A), several buried 6-0 nylon or Prolene (polypropylene) or Dexon (polyglycolic acid) sutures are applied to create adhesions between the levator aponeurosis and the subcutaneous tissue of the inferior incision along the superior tarsal border ( Figure 5-5 ). The technique contains buried sutures. According to Fernandez, this also creates a “dynamic” crease, but a deeper and permanent one in comparison to the first method of closure (see Option 1(A)), which tends to be not quite as deep. It could be the result of tissue fixation with buried Prolene sutures at a deeper level.