Fig. 17.5 Side view of a patient revealing negative vector eyelid as the globe protrudes further than the suborbital rim tissue

lid tightening is always warranted. An omission of this step will most assuredly lead to lower eyelid malposition. In transconjunctival surgery, the lower lid is at less risk of lid retraction or ectropion, and lid tightening is needed only if the degree of laxity is more significant or if a separate skin excision is to be performed.

It is also important to evaluate globe prominence when considering lid tightening. When the anterior projection of the globe protrudes further than the midface, a negative vector eyelid is present (Fig. 17.5). This can occur as a result of

Fig. 17.6 Illustration of canthal suspension in a prominent globe. Note “bowstringing of the globe.” with increased sclera show (dotted line to arrow)

relative globe prominence (large eye, shallow orbit, etc.) or midface (bone/soft tissue or both) recession. When the lower lid is tightened in this scenario, it can bowstring the globe, increase or create scleral show (true or pseudo-lid retraction), and make the eye (globe) appear more prominent (Fig. 17.6). There are techniques to reduce these complications (see surgical technique section below and Chap. 26). However, in this setting, it may be prudent to forgo the blepharoplasty altogether.

17.4Surgical Techniques

As previously mentioned, it is important to differentiate reconstructive canthal surgery from the aesthetic procedure. The traditional canthoplasty was described for the reconstructive patient with significant eyelid laxity and malposition [15, 16]. This surgery involves complete disinsertion of the lower eyelid from its attachment to the lateral orbital

rim (canthotomy and cantholysis). The terminal eyelid is then shortened and resecured to the bone via a tarsal tongue. This lateral tarsal strip technique is the classic canthoplasty procedure [17]. While the surgery is not overly complex in the hands of an experienced surgeon, it does involve significant anatomical distortion. In the best of hands, this surgery can lead to small degrees of canthal malalignment and changes in the canthal angle. This is well-tolerated by the older reconstructive patient with involutional eyelid changes. The procedure is not appropriate for the typical cosmetic eyelid patient where complete surgical eyelid disinsertion and lid shortening is rarely needed. In cosmetic surgery, a tarsal strip is typically reserved for patients who are older with more severe lid changes (excess skin, rhytids, laxity, etc.). In this small sub-group of aesthetic patients, the overall improvement in appearance after surgery is so significant that a discrepancy of the two canthi after surgery is usually not a significant concern.

In most aesthetic blepharoplasty patients who require lower lid tightening, two other procedures will likely provide a better overall outcome: a modified canthoplasty or a canthopexy. The incidence of postoperative canthal angle changes or discrepancies between sides is much less common with these procedures. All three procedures will be described below. These three techniques will allow the surgeon a full spectrum of canthal suspension surgical options which can be tailored to each patient depending of preoperative findings.

17.4.1 Canthoplasty (Lateral Tarsal Strip)

The canthus is anesthetized transcutaneously to the lateral orbital rim periosteum and transconjnuncitvally with Xylocaine 1% with 1:100:000 epinephrine. A 7–8 mm canthotomy is performed (Fig. 17.7). An incision is made

through orbicularis muscle to the orbital rim periosteum. Blunt dissection with a cotton-tipped applicator is useful for freeing tissue off the periosteum. It is not uncommon to identify a small fat pad (Eilser’s fat) during this step. This fat pad should be left undisturbed if possible. The terminal eyelid is grasped with a toothed forceps and a Wescott scissors or an electrical cutting device is used to engage the inferior crus of the LCT (feels like a dense band). This attachment is lysed with a resultant dynamic release of the eyelid (Fig. 17.8). The amount of lid shortening is then determined by bringing the lid to the inner orbital rim and approximating the excess. The tarsus is released from the conjunctiva and retractors below (Fig. 17.9). The corresponding amount of lid margin is then trimmed (Fig. 17.10), and the anterior and posterior lamellae are split (Fig. 17.11). The excess skin is excised (Fig. 17.12) and the tarsal tongue is now formed. The tarsus is then de-epithelialized with a scalpel or light cautery. The tarsus is shortened as needed and engaged with a suture for reattachment (Fig. 17.13). A 4–0 Vicryl suture on a half-circle needle (P2 or S2) is utilized for the suspension. Vicryl suture works well as it is reactive (induces scar) and absorbs after 3 months, thus avoiding suture spitting which can occur with permanent sutures. The tarsus is secured to the inner periosteum of the lateral orbital rim (Fig. 17.14a) at the level of Whitnall’s tubercle. After the periosteal bite is completed, the suture can be passed through the superior limb of the LPL. This maneuver aids in formation of the canthal angle. The suture is approximated without tying in order to assess the lid position. I prefer a slight (2 mm) over-correction in anticipation of postoperative drop. If lid position is appropriate, the suture is tied (Fig. 17.14b). The canthal angle is then reformed with a grey line–grey line suture (see detailed description in modified canthoplasty section). The canthus is closed with either absorbable (6–0 chromic) or permanent (6–0 silk) suture (Fig. 17.15). The permanent sutures are removed in 1 week.