Lower eyelid plasty: surgical procedure

The following main surgical approaches are used for lower eyelid plastic surgery:

• transconjunctival,
• through a skin-muscle flap,
• through a skin flap.

Transconjunctival approach

The transconjunctival approach to lower eyelid surgery was first described in 1924 by Bourquet. Although it is not a new procedure, there has been a surge of interest and support for this approach in the last 10 years. Transconjunctival lower eyelid surgery preserves the integrity of the orbicularis muscle, the active supporting structure of the lower eyelid. This minimizes the risk of ectropion. Also, no external scar is formed.

Transconjunctival surgery requires proper patient selection. Ideal candidates include elderly patients with pseudoherniated orbital fat and mild skin excess, young patients with familial herniated orbital fat without skin excess, all patients requiring correction of previous blepharoplasty, patients unwilling to have an external scar, patients with a predisposition to keloids, and dark-skinned patients who have some risk of hypopigmentation of the external scar. Since some authors have reported a significant reduction in the incidence of early and late complications after transconjunctival lower eyelid surgery compared with the musculocutaneous method, the indications for this procedure are gradually expanding. The presence of excess skin on the lower eyelid does not preclude the use of the transconjunctival approach. In the practice of the first author of this chapter, the most commonly performed lower eyelid surgery consists of transconjunctival fat excision, pinch skin excision, and 35% trichloroacetic acid peel (described below). After fat excision, skin excision is required to correct the lower eyelid contour. Frequently, after fat excision, there is less excess skin than previously thought.

• Preparation

The patient is asked to look upward in a sitting position. This helps to refresh the surgeon's memory as to the most prominent fat pads, which are marked. The patient is then placed supine. Two drops of 0.5% tetracaine hydrochloride ophthalmic solution are instilled into each inferior fornix. Before the local anesthetic injections are given, our patients are usually given some sedation with intravenous midazolam (Versed) and meperidine hydrochloride (Demerol). To reduce postoperative swelling, 10 milligrams of dexamethasone (Decadron) is given intravenously. A local anesthetic mixture of equal parts 0.25% bupivacaine (Marcaine) and 1% lidocaine (Xylocaine) with 1:100,000 epinephrine and 10-fold sodium bicarbonate is then injected into the lower tarsal conjunctiva through a 30-gauge needle. Experience has shown that this mixture provides a long-lasting analgesic effect, minimizing the acute pain of the initial infiltration by alkalization. The needle is advanced through the conjunctiva until it contacts the bony orbital rim. The anesthetic is injected slowly in the medial, lateral, and central directions as the needle advances. Some surgeons prefer to inject into the V2 area through the skin, although we believe this is usually unnecessary and may cause unnecessary trauma.

• Section

After a 10-minute pause to allow vasoconstriction to occur, the assistant gently pulls down the lower eyelid with two small two-pronged hooks. A ball is placed under the upper eyelid to protect it. Either an insulated needle electrode, at low current settings, or a #15 scalpel is used to make a 2-mm transconjunctival incision beneath the lower edge of the lower eyelid plate. The lower edge of the eyelid plate appears gray through the conjunctiva. The medial portion of the incision is level with the inferior lacrimal punctum. The incision is only 4-5 mm short of the lateral canthus.

Immediately after the transconjunctival incision is made, a single 5/0 nylon stay suture is placed in the conjunctiva as close to the fornix as possible and is used to retract the posterior lamella from the cornea. The suture is held in tension with a mosquito clamp attached to the surgical drape covering the patient's head. The conjunctiva acts as a corneal protector, and its upward retraction makes it easier to determine the dissection plane. Both skin hooks are carefully removed, and a Desmarres retractor is used to evert the free edge of the lower lid.

The distance of the transconjunctival incision from the inferior margin of the lower lid plate determines the choice of a preseptal or retroseptal approach to the orbital fat. We usually use the former approach; therefore, our incisions are always approximately 2 mm below the lid plate. The preseptal plane is an avascular zone between the orbicularis oculi muscle and the orbital septum. Since the orbital septum is not disturbed during dissection in the preseptal plane, the orbital fat does not bulge into the field of view. The resulting appearance is very similar to that of a myocutaneous blepharoplasty. In order to gain access to the underlying orbital fat, it will still be necessary to open the orbital septum.

Other surgeons prefer a transseptal approach to the orbital fat pads. To directly access the fat pads, the conjunctiva is incised approximately 4 mm below the inferior margin of the lower eyelid plate and directly toward the anterior infraorbital margin. The great advantage of this method is that the orbital septum is left completely intact. Proponents of this technique note that an intact orbital septum provides better support for the lower eyelid. A disadvantage of the approach is that orbital fat immediately protrudes into the wound. To avoid the formation of synechiae, the incision should not be made close to the blind sac of the conjunctiva. Also, the view from the direct approach is one to which most facial plastic surgeons are less accustomed.

After the application of the stay suture and the installation of the Desmarres retractor, the preseptal space is worked by a combination of blunt dissection with a cotton swab and sharp dissection with scissors. It is necessary to keep the surgical field dry. Therefore, bipolar coagulation, "hot loop" or monopolar coagulation are used to stop the slightest sources of bleeding.

The medial, lateral, and central fat pads are individually identified through the septum by applying gentle pressure to the conjunctiva covering the globe. The orbital septum is then opened with scissors. Excess fat is carefully brought out over the orbital rim and septum with a clamp or cotton swab. Only excess and herniating fat should be removed, as excessive fat removal can cause the eyes to appear sunken. The main goal is to achieve a lower eyelid contour that forms a smooth, gradual concave transition to the cheek skin. A small amount of local anesthetic is then injected into the isolated excess fat with a 30-gauge needle. The pedicle of the fat protrusion is treated with a bipolar coagulator. Once the entire pedicle has been coagulated, it is excised with scissors. Others, especially Cook, reduce the fat by cauterizing it with an electrocautery, thereby minimizing surgical excision. Many surgeons believe that the lateral fat pocket should be treated first, as its contribution to the overall fat protrusion becomes much more difficult to assess once the adjacent and associated central fat has been removed. After excess fat has been removed from each space, the surgical field is inspected for bleeding. Although carbon dioxide laser fat excision has been advocated for its hemostatic efficacy, precision, and reduced tissue trauma, the increased cost, need for highly trained personnel, and additional safety precautions associated with the laser have led us and many others to abandon the use of the laser in lower eyelid surgery.

To facilitate the assessment of the eyelid contour, the Desmarres retractor should be periodically removed and repositioned, positioning it over the remaining fat. The removed fat is laid out on a drape in the surgical field sequentially, from the lateral to the medial edge, allowing comparison with that removed on the other side. For example, if the surgeon considered the right lateral fat pocket to be much larger than the others before the operation, the greatest amount of fat can be removed from this space during the procedure.

The medial and lateral spaces are separated by the inferior oblique muscle. To prevent injury to the muscle, it must be clearly localized before excising excess fat from these spaces. The fat in the medial space is lighter than that in the central and lateral spaces. This helps in recognizing it. The lateral space is usually isolated from the central space by a fascial band from the inferior oblique muscle. This fascial band can be safely cut.

After each space has been successfully treated, the entire surgical space should be re-examined for bleeding. All sources of bleeding are bipolarly coagulated, and the Desmarres retractor and stay suture are removed. The lower eyelid is gently moved up, down, and then allowed to settle into its natural position. This aligns the edges of the transconjunctival incision. No suturing is required, although some surgeons feel more comfortable closing the incision with a single immersion suture of rapidly absorbable 6/0 catgut. Both eyes should be irrigated with sodium chloride (Ophthalmic Balanced Salt Solution).

In older patients, when there is excess skin, chemical peeling or pincer skin excision can now be performed. Using a hemostatic or Brown-Adson clamp, a 2-3 mm fold of excess skin is grasped and elevated just below the lash margin. This fold is excised with sharp scissors without trimming the lower lashes. The resulting excision edges are sutured with a continuous suture of rapidly absorbable 6/0 catgut. Some authors close such incisions with cyanoacrylate (Histoacryl) or fibrin glue.

In patients with fine wrinkles on the lower eyelids, correction can be done by peeling with 25-35% trichloroacetic acid. Trichloroacetic acid is applied directly under the area of pinch excision. A typical "frost" is formed. We do not use phenol on the lower eyelids, since it produces a much longer erythema and inflammatory phase than peeling with trichloroacetic acid.

• Post-operative care

Immediately following surgery, the patient is kept at rest with the head elevated at 45°. Cold compresses are applied to both eyes and changed every 20 minutes. The patient is closely observed for at least an hour for any signs of postoperative bleeding. The patient is given specific instructions to limit physical activity for a week. Patients who are diligent about cold compresses and head elevation for the first 48 hours experience much less swelling. Some physicians prescribe sulfacetamide eye drops for the first 5 days after surgery to prevent infection while the transconjunctival incision heals.

Skin-muscle flap

The myocutaneous flap approach was probably the most widely used technique in the 1970s and early 1980s. This procedure is excellent for patients with large amounts of excess skin and orbicularis oculi muscle, as well as fatty pseudohernias. The advantages of this approach are the safety and ease of dissection in a relatively avascular plane beneath the muscle and the ability to remove excess lower eyelid skin. It must be recognized that even with this approach, the ability to remove skin is limited by the amount that can be excised without risking scleral exposure and ectropion. Stubborn wrinkles usually persist despite attempts to resect excess eyelid skin.

• Preparation

Preparation for this procedure is the same as for the transconjunctival approach, except that tetracaine drops are not required. The incision is marked with a marker or methylene blue 2 to 3 mm below the lower lid margin with the patient in a sitting position. Any protruding fat pads are also marked. The importance of marking in a sitting position is due to changes in soft tissue relationships that occur as a result of infiltration and gravity. The medial end of the incision is marked 1 mm lateral to the inferior lacrimal punctum to avoid the lacrimal canaliculi, and the lateral end is brought 8 to 10 mm laterally from the lateral canthus (to reduce the possibility of canthal rounding and lateral scleral exposure). At this point, the most lateral portion of the incision is given a more horizontal direction so that it lies within the folds of the anserine foot. When planning the lateral part of the incision, it is necessary to take into account that the distance between it and the incision for upper eyelid plastic surgery here should be at least 5 mm, preferably 10 mm, to prevent long-term lymphedema.

After marking is completed and intravenous dexamethasone is administered, our patients are usually given intravenous sedation consisting of midazolam and meperidine hydrochloride. Before limiting the surgical field with linen, the incision line (from the lateral end) and the entire lower eyelid, up to the lower edge of the orbit, are infiltrated (superficial to the orbital septum) with the anesthetic mixture described above.

• Section

A #15 scalpel blade is used to make a medial incision to the level of the lateral canthus dividing only the skin and then laterally from this point, the skin and orbicularis oculi muscle. Using straight blunt scissors, dissection is performed under the muscle, from the lateral canthus to the medial canthus, and the muscle is then divided with the blades directed caudally (optimizing the integrity of the pretarsal muscle bundle). A Frost stay suture is then placed through the edge of the tissue above the incision with 5/0 nylon to facilitate countertraction. Bluntly (with scissors and cotton swabs), the skin-muscle flap is worked down to the inferior margin of the orbit, but not below it, so as not to damage important lymphatic channels. Any sources of bleeding here should be carefully stopped with bipolar coagulation, without damaging the eyelash hair follicles at the superior margin of the incision.

• Fat removal

If preoperative examination has revealed the need to treat the fat pads, targeted incisions are made in the orbital septum over the pseudohernias, the location of which is determined by gentle digital pressure of the closed eyelid to the eyeball. Although an alternative in the form of electrocoagulation of the weakened orbital septum exists, which can protect this important barrier, we are satisfied with the long-term results and the predictability of our technique of direct access to the fat pockets.

After opening the septum (usually 5-6 mm above the orbital rim), the fat lobules are carefully brought out above the orbital rim and septum using a clamp and cotton swab. The technique of fat resection is described in detail in the section on the transconjunctival approach and is not repeated here.

Access to the medial space may be somewhat limited by the medial portion of the subciliary incision. The incision should not be widened; instead, the fat should be carefully brought into the incision, avoiding the inferior oblique muscle. The medial fat pad is lighter in color than the central fat pad.

• Closing

Before excising the skin and closing the wound, the patient is asked to open the mouth wide and look upward. This maneuver induces maximum voluntary separation of the wound edges and helps the surgeon perform precise resection of the musculocutaneous layer. With the patient in this position, the inferior flap is placed over the incision in a superior and temporal direction. At the level of the lateral canthus, the overlapping excess muscle is marked and incised vertically. A 5/0 rapidly absorbable catgut suture is placed to hold the flap in place. The overlapping areas are resected sparingly (medial and lateral to the retention suture) with straight scissors so that the wound edges are approximated without forcible reduction. It is important to direct the scissor blades caudally to preserve a 1- to 2-mm strip of orbicularis oculi muscle on the inferior flap to prevent the formation of a protruding ridge during suturing. Some surgeons freeze the resected skin (keeping it viable for at least 48 hours) in sterile saline in case replacement grafting is needed after over-resection resulting in ectropion. It is far better to prevent this complication by performing a sparing resection.

After the second eyelid fat has been removed, the first eyelid incision is closed with simple interrupted 6/0 rapidly absorbable catgut sutures. The second eyelid is then sutured, incised, and closed. Finally, quarter-inch (0.625 cm) sterile strips are applied over the sutures, and a small amount of antibacterial ointment is applied to the incision after the eye has been flushed with isotonic saline.

• Post-operative care

Post-operative care for the musculocutaneous procedure is generally the same as after the transconjunctival technique. Bacitracin eye ointment is applied to the subciliary incision. All patients are prescribed cold compresses, head elevation, and limited physical activity.

Skin flap

The flap approach is perhaps the oldest and most underused approach. This technique allows for independent resection and approximation of the lower eyelid skin and the underlying orbicularis oculi muscle. It is effective in repositioning and removing severely wrinkled, redundant, and deeply folded skin. In cases where there is hypertrophy or scalloping of the orbicularis oculi muscle, a direct approach is used for correction, allowing for safer resection than would be possible with a combined myocutaneous block. Disadvantages of this approach include a more tedious dissection with greater skin trauma (indicated by increased bleeding and lid infiltration), an increased risk of vertical lid retraction, and a greater burden on preoperative assessment of fat pockets because the orbital septum is covered by the orbicularis oculi muscle during surgery.

First, a skin incision is made to facilitate the undercut only in the lateral part, carried out under the eyelashes of the mark. The assistant pulls the skin of the lower eyelid down (placing the hand at the edge of the orbit), the lateral end of the incision is grasped and pulled up; at the same time, using a sharp method, scissors, the skin flap is carefully undercut to a level immediately below the edge of the orbit. After the undercut is complete, the subciliary incision is extended with scissors. All sources of bleeding are targeted coagulated.

If the only problem is excess skin or excessive wrinkling, the skin flap is simply placed over the incision and dissected as described for the myocutaneous flap. If access to the orbital fat spaces is required, it is obtained by incising the orbicularis oculi muscle approximately 3 to 4 mm below the initial skin incision or by a transconjunctival approach. However, when there is hypertrophy or scalloping of the orbicularis oculi muscle, optimal correction is achieved by creating independent skin and muscle flaps. In this case, the muscle is incised (with a caudal bevel) along and approximately 2 mm below the skin incision to preserve the pretarsal band of muscle. Dissection of the muscle flap is carried to a level just below the most overhanging (scalloped) muscle ridge or to a point that will allow, after resection, smoothing of the prominent (hypertrophic) muscle sac. After the fat pads have been treated, the muscle flap is reinforced by suturing its lateral end to the orbital periosteum with 5/0 Vicril thread and aligning the pretarsal muscle edges with several interrupted 5/0 chromic catgut sutures. The skin is closed as described above.

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