Lateral canthal repositioning in syndromic, antimongoloid slant.

INTRODUCTION: To report a single center's experience in correcting antimongoloid slant in Asian eyes using a minimally invasive approach.
METHODS: Retrospective analysis of patients undergoing correction for antimongoloid slant at author's center, from 2007 to 2013 formed the study group. Concomitant surgical procedures were recorded. Pre- and post-operative photographs at the longest follow-up visit were analyzed and graded for functional and cosmetic outcomes.
RESULTS: A total of 38 patients (76 eyelids) underwent successful correction to correct eyelid malposition. All patients' eyelids underwent exclusive lateral canthoplasty through a small incision in the upper eyelid crease and re-suspension technique, and 6 of them underwent bilateral slant correction simultaneously with additional cosmetic or corrective surgeries including hemifacial microsomia and Crouzon's syndrome. Of the 38 patients, 25 were females and 13 were males. The age of the population ranged from 7 to 48 years with a mean age of 27 years. Few instances of transient postoperative chemosis lasting up to 2 weeks and minor infections were reported. All cases showed improvement in eyelid position (as assessed clinically and on photographs), 2 pediatric cases required reoperation in the following 2 years for the recurrent lower eyelid malposition and/or lateral canthal deformity owing to deviated basal bone growth. DISCUSSION: Lateral canthoplasty with resuspension technique can effectively address antimongoloid slant for an esthetically desirable lateral canthus.

INTRODUCTION

A typical Indian eye is one of the types of the Asian eye, which has a double eyelid. Such common double eyelid type is further subcategorized based on the eyelid crease morphology.[1] Due to several craniofacial anomalies or developmental defects, the eyelid morphology may be deviated giving rise to abnormal features. This stems from the fact that during embryological development, the development of mid-facial structures is closely linked with that of the eye and anatomically, the orbital floor is formed by a part of the maxilla.[2] Hence, any anomalies affecting the maxilla also affect the orbital fissures.

Slight mongoloid slant and prominent epicanthal fold are features of the Asian eye.[1] In normal individuals, the inner and outer canthi of the eye are expected to be along the same plane. Minor variation arises from the abnormal location of the periosteal fixation of the lateral palpebral ligament that alters the typical “slant” of the eye. An eye is said to have a Mongoloid slant when the outer canthus is placed higher than the inner canthus while in the antimongoloid slant, the outer canthus is placed lower than the inner canthus.[3] Of such anomalies, mongoloid slant and antimongoloid slant are the most characteristic ones. Such visible variations may be esthetically undesirable. In addition to developmental defects, aging process due to sagging of lower eyelid could cause the relative “drooping” of the eye.[4] Correction of the lateral canthal angle is an important component in the rehabilitation of the maxillofacial complex. As the outer canthus merges with the: (1) Part of the upper eyelid to continue as the forehead and (2) a part of lower eyelid to form the midface, the esthetic demand of this part cannot be understated, and its proper restoration is essential.[5]

Numerous corrective surgical procedures have evolved through the years to correct the antimongoloid abnormalities.[67] Many of them arise from previously practiced correction of the eyelid ectropion and “drooping” in facial palsy.[89101112131415161718192021] Later dermal flaps were even tried. Repositioning of the palpebral ligament through bicoronal incision or a transconjuctival route and even canthoplasty were suggested. The fundamental, bio-mechanical principle behind such attempt is to correct the abnormal loss of lateral canthal support from gravitational or other mechanical, biological, or other factors.[22] The surgical concept of tightening lower eyelid advocated by Bick in 1966 and its subsequent modifications lead to further evolution owing to a certain degree of unsatisfactory postoperative results.

A canthopexy surgical maneuver involves tightening the ocular lateral canthal tendon without involving the canthal angle while canthoplasty involves either a canthotomy – cantholysis before resuspending the lower eyelid to the lateral orbital rim periosteum.[7] Depending on nature, the extent of deformity, functional impairment (if any), the level of correction required, a canthopexy or canthoplasty is performed. Herein, the manuscript intends to describe our technique and experience in using a minimally invasive approach for aesthetic lateral canthal correction.

METHODS

The charts of all patients undergoing lateral canthoplasty for anti-mongoloid slants at our center performed during January 2007 to December 2013 operated by the author were reviewed. Lateral canthoplasty which were performed through a minimally invasive upper eyelid crease approach were only included for this study. Concomitant surgical procedures, if any, were recorded separately. Patient with other significant orbital deformities or functional impairment were excluded from this study. Patients without standard digital pre- and post-operative photographs for review were excluded from this study. Pre- and post-operative photographs at the longest follow-up visit were analyzed and graded for functional and cosmetic outcomes. Both pre- and post-operative photographs were earlier obtained using a previously, standardized, published technique in the frontal position with the eyelids completely open and facial muscles relaxed. Such a technique of using photographs for comparison of eyelid position measurements has been established in previous studies.[623] Complications were recorded from the case sheets.

Surgical procedure

All ocular surgeries were performed under standard general anesthetic care. Local infiltration of lidocaine with 2% epinephrine was copiously injected in the area to prevent bleeding. In the canthotomy procedure, a small lateral [Figure 1] incision along the natural skin creases was placed in the lateral part of the upper eyelid. Through the lateral part of the incision, using Steven's scissors, blunt and sharp dissection was carried to expose the lateral canthal tendon as well as the lateral aspect of the orbital rim. Stabilizing the one arm tip of scissors, the lateral canthal tendon fibers were dissected from their periosteal attachments. This is marked so that it serves as a landmark to avoid asymmetries. At all possible aspects, the Eisler's fat pad was preserved. Furthermore, if required, fat removal or additions, depending on the requirement in the lateral fat pocket was carried out. Debulking or grafting (with bolster stabilization) was also done.

Figure 1

(a and b) Preoperative Frontal and Lateral view. (c) Lateral canthotomy incision of the right eye. (d) Lateral Canthal tendon is sutured to the Whitnall's tubercle. (e and f) Postoperative Frontal and Lateral view

The lateral tarsal strip (LTS), a useful oculoplastic procedure to shorten the lower eyelid was carried out if indicated. LTS does not distort the lateral canthal angle or change the dimension of the palpebral aperture. Manipulation of the tarsal strip which is superolaterally placed along inner aspect of the lateral orbital rim, to be elevated and straightened to give a youthful appearance was performed if required. If required a fat graft was placed and stabilized.

An absorbable suture 6-0 Vicryl on double armed needle was used to reattach the lateral canthus to the Whitnall's tubercle along the inner aspect of the orbital rim, at the appropriate vertical height. The 2 needles were both passed at the same spot along the lateral aspect of the lower eyelid tarsus. By positioning the needle in such a way that one head pierces the tarsus while the other needle is pierced more superficial through the upper part of tarsus, a loop was created that engaged substantial tarsal tissue. With optimal tension on the lower eyelid, the suture was then tied and the knot tucked below the orbicularis of the lateral eyelid crease incision.

Alternatively, two small holes are carefully drilled along the lateral wall of the orbital rim. The raised tarsal strip is secured to the holes using nonresorbable 4-0 prolene sutures. This together with the fat graft would help to elevate the eyelid. This results in correction of the palpebral position. A slight overcorrection was done so that it compensates for any later physiological remodeling. The Indian double eyelid would be an excellent mask to hide for this minor correction.

Postoperative stabilization with bolsters, if present were used for a week, after which it is removed. Standard antibiotics and nonsteroidal anti-inflammatory drugs tablet diclomol were prescribed for 5 days as required. Eyes were kept under patch for 2 days.

Data and details thus collected were analyzed and presented. Descriptive statistics are presented.

RESULTS

A total of 38 patients involving 76 eyelids underwent exclusive lateral canthoplasty through a small incision in the upper eyelid crease and resuspension technique, with quick recovery. Of them, 6 patients simultaneously underwent additional cosmetic or corrective surgeries including hemifacial microsomia and Crouzon's syndrome. Of these 38 patients, 25 were females and remaining 13 were males.

The syndromes include Apert syndrome, Mobius syndrome, Crouzon syndrome, and Treacher-Collins syndrome. The age of the population ranged from 7 to 48 years with a mean age of 27 years.

Photographs were analyzed for lower eyelid position and lateral canthal position as outlined earlier. We identified that in the present cohort, all of them had abnormal canthal tilt, majority of them had abnormal sclera show – 78% of all cases and abnormal negative vector (globe projects anterior to rim) in 35%. All such deviations are corrected by this repositioning.

Representative cases are shown in Figures 2–4. There were no instances of lower eyelid retraction, ectropion, entropion, hematoma, infection, or untoward external scarring. Very few instance of transient postoperative chemosis lasting up to 2 weeks and minor infections which were suppressed using appropriate therapies. All cases showed improvement in eyelid position (as assessed clinically and on photographs), 2 pediatric cases required reoperation in the following 2 years for recurrent lower eyelid malposition and/or lateral canthal deformity owing to deviated basal bone growth.

Figure 2

(a) Preoperative Frontal view. (b) Immediate postoperative view

Figure 4

The posterior insertion of the lateral canthal tendon into the Whitnall tubercle.

The tarsoligamentous sling

DISCUSSION

Lateral canthoplasty initially evolved as core ophthalmic procedure to rectify eyelid function along with correction of lower eyelid malposition [Figure 5]. As of now, it has evolved a major cosmetic correction for aging and sagging eyes.[46] In other asyndromic situations, (NOT in the present cohort) owing to the biochemical changes associated with age in the tendons of the eye, especially the lateral canthal tendon, there appears a drop of lateral canthus and possible inferior migration of the lower eyelid.[46] In congenital syndromic or defective cases as in this cohort, the abnormal formation of the orbital rim or the uncoordinated, peri-orbital musculature development may contribute to the development of abnormal slants. Additional minor variation in positioning, altered development, structural variation could contribute to the abnormal outer canthal positioning. Trauma to the midfacial structures could also contribute to the alteration in the normal slant owing to the improper rehabilitation of anatomical or functional integrity.

Figure 5

Algorithm for the management of lower eyelid malposition

In the center, author's preference is the open canthal incision. This incision, if handled improperly could give rise to a series of unpleasant results. The importance of such unpleasant result is due to the loss of junction of the tendon of the upper and lower eyelid. This could contribute to length disparity and unpleasant ocular esthetics. In addition, the sclera show or misalignments could be a possibility. Inappropriate, closure could lead to improper “rounding of the canthus.” At the same time, the surgical technique used here does not alter the mucocutaneous border of the lateral canthus, as the anatomy of the outer angle of the eye is left untouched. In addition, the tarus manipulation and additional fat grafting would reduce the “aging” or “sagging” look, especially in elderly patients.[467]

Although there are several other eyelid and angle correction techniques, the correction of excessive slant (antimongoloid) is complex. For a successful correction, the identification of the flaw is the basic. Although numerous causes for the condition are possible, unless the deviation from “normal” is identified, repositioning or correction may be compromised. The slant can be successfully repositioned; if and only when the lateral palpebral ligament is separated from its orbital bone attachment and the orbital septum is freed laterally from orbital rim. Unless these procedures are carried out slant correction are far less permanent. Additionally relapse, the functional loss would be the side-effects of misadventure.[46]

This minimally invasive lateral canthoplasty helps to correct the slant and gives aesthetic results in both reconstructive and cosmetic correction. Sparing of the extreme angle decreases the incidence of postoperative scarring, avoiding late length disparity and maintaining the proper lymphatic drainage of the eyes. Furthermore, additional eye surgeries can be performed. In addition to correction of the slant, the scleral show is decreased, vector positioning abnormality is cleared and globe position abnormalities are set right. Additional fat grafts are helpful to regain the ocular “youthfulness”.[67]

As most of the loco-regional anatomy of the mucocutaneous lateral canthal angle is not grossly violated, the natural lymphatic and blood circulation is not violated. This significantly reduces the possibility of the postoperative lymphedema, misalignment of the upper and lower tendons, and scarring or web formation. An additional benefit is that this approach can be performed along with concurrent other ocular or midfacial corrective surgeries.[6]

In the present case series, it has been shown that there has been successful long term, esthetically pleasing results for the correction in the complex Indian eye. The combined approach and reanimation/repositioning of the ocular musculature sling compensates for the naturally adapted slants of the eye.

CONCLUSION

A single center experience of correction of antimongoloid slant is presented. The identification of the defect is the clue to the success of the rehabilitative procedure. Author's version of the surgery has been shown to fetch reliable and lasting result. More long-term studies are needed in this direction, especially multi-centric ones and those in combination with other ocular defect rehabilitation.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.