Keywords lagophthalmos - facial palsy - lid load - gold weight implantation - supratarsal implantation
Introduction
Paralytic lagophthalmos in lower motor neuron facial nerve palsy can lead to exposure
keratitis, which can progress to severe ocular infection and corneal scarring. Current
permanent surgical treatment modalities for paralytic lagophthalmos include static
and dynamic options. Reanimation of the upper face is a dynamic option preferred only
in patients with paralysis for less than 24 months. For long-standing cases, static
treatment modalities, including permanent tarsorrhaphy, upper lid loading surgery,
and levator lengthening procedures, are more favorable.[1 ]
[2 ] Upper lid loading surgery is a procedure of choice owing to its effectiveness, simplicity,
and reversibility. However, the occurrence of postoperative, long-term, implant-related
complications is fairly common and usually results in revision surgeries.[3 ]
[4 ]
The traditional gold weight model is designed to be placed anterior to the tarsus
(pretarsal area) of a Caucasian eye with a trapezoid tarsal shape.[5 ] Visibility of the edge of the implant is frequently observed in Asian eyes with
a sickle-shaped tarsus, leading to poor cosmetic outcomes and high rates of implant
infection, exposure, and reoperation.[6 ]
[7 ] Recently, supratarsal implant placement has become more popular among surgeons due
to the reduced implant visibility and exposure rate associated with the procedure.[8 ]
[9 ]
[10 ] We redesigned the lid load implant and made it thinner to fit the post-levator space
and sickle-shaped tarsus of Asian eyes. The primary objective of this study was to
compare the clinical outcomes of the newly designed supratarsal gold weight implantation
with those of the traditional pretarsal gold weight implantation for the correction
of paralytic lagophthalmos in Asian eyes.
Methods
This was a retrospective cohort study of patients with facial palsy who underwent
gold weight implantation performed by a single surgeon (P.S.), from May 2014 to April
2019. We obtained approval for this study from the Institutional Review Board and
Ethics Committee, Faculty of Medicine, Chulalongkorn University (IRB No.672/62). This
study adhered to the tenets of the Declaration of Helsinki. Data collected included
patient demographics and preoperative and postoperative clinical measurements such
as upper eyelid contour, upper eyelid ptosis, weight prominence, weight migration,
and improvement of lagophthalmos. The 12-month postoperative outcome was graded by
five independent, masked, oculoplastic surgeons who assessed subject-standardized
photographs. Early and late (24-month) postoperative complications, including exposure
keratitis, wound infection, hemorrhage, implant exposure, and reoperative rate, were
also recorded. Patients who underwent the surgery but were lost to follow-up were
excluded from this study.
The supratarsal gold weight model was designed based on the average dimension minus
2 standard deviations (mean − 2 SDs) of the anatomy of 50 eyelids from 25 Asian cadavers
with a sickle-shaped tarsus. The gold weight has a semielliptical shape and a height
of 8.8 mm, with the widest base length being 22.4 mm and radius of curvature of 12.7 mm
([Fig. 1 ], courtesy of Wittaya Gasamwattana, 2020, Bangkok: Learnery Co., Ltd, all rights
reserved).
Fig. 1 The approximate height and width of the 1.2 g traditional pretarsal gold weight (upper)
compared with the newly designed elliptical supratarsal gold weight (lower; courtesy
of Wittaya Gasamwattana, 2020, Bangkok: Learnery Co., Ltd, all rights reserved).
The weight was created in eight sizes ranging from 0.8 to 2.2 g, with a 0.2 g increase
in weight per increase in size. The weight chosen for the traditional pretarsal model
is based on the trial weight used in the Tantalum Weight Sizing Set (MedDev, USA),
whereas that chosen for the supratarsal model is based on the trial weight of the
set plus 0.2 g as recommended by a previous article on supratarsal placement method.[10 ] The surgical techniques for supratarsal gold weight implantation have been described
previously by Caesar et al[8 ] and were modified as described. Local anesthetic with 2% xylocaine with 1:200,000
adrenaline was done. An eyelid crease incision and dissection to expose the superior
tarsal border was performed. The orbital septum is opened and the levator aponeurosis
is separated from the Muller's muscle. The gold weight is centered at the superior
border of the tarsus and sutured through the medial and lateral holes with two 6/0
polyglycolic acid (PGA) sutures. The edge of the levator aponeurosis was reattached
to the tarsus with 6/0 PGA suture in horizontal mattress pattern. Orbicularis and
skin are closed with 6/0 PGA and 7/0 nylon suture in an interrupted pattern, respectively.
In the cases of revision surgery, the preexisting gold weight was removed and replaced
with the supratarsal model, which was chosen based on the patient's previous implant
weight plus 0.2 g. The surgery was performed under local anesthesia as described below.
A skin incision was made at the level of the lid crease, 2.5 to 3 cm in length, and
monopolar cautery was used to dissect and identify the fibrous capsule around the
previous implant. The part of the capsule anterior to the implant was excised and
removed. The fixation suture was severed, and the implant was then removed. The part
of the capsule posterior to the implant was dissected from the underlying tarsus to
the post-levator space. The levator aponeurosis was separated from Muller's muscle
to form a single sheath comprising the fibrous capsule and the levator aponeurosis.
The gold weight was centered at the upper border of the bare tarsal surface and sutured
directly to the upper border of the tarsus with 6/0 PGA sutures and two-point fixation.
The fibrous capsule–levator aponeurosis complex was reattached to the upper border
of the tarsus, medial and lateral to the implant, using a 6/0 PGA suture in a horizontal
mattress pattern. The margin to reflex distance was used to check the eyelid position
intraoperatively to prevent unintentional levator advancement. With the eyelid in
a proper position, the redundant fibrous capsule was then trimmed. Eyelid crease fixation
was performed using 6/0 PGA sutures in an interrupted pattern, from the margin of
the fibrous capsule to the pretarsal orbicularis oculi. The skin was closed with a
7/0 nylon suture in an interrupted pattern. Postoperative medication included dicloxacillin
(500 mg) four times daily and Maxitrol® eye ointment (Alcon Pharmaceutical, USA) twice
daily. The skin sutures were removed 7 to 10 days postoperatively.
Five masked oculoplastic surgeons independently graded standard photographs ([Figs. 2 ] and [3 ]) for weight prominence, weight migration, improvement of lagophthalmos, upper eyelid
contour, and upper eyelid ptosis. Prior to the assessment of the photographs, the
reviewers were informed of the photograph grading system previously reported by Bladen
et al.[4 ] Weight prominence was assessed in eyelid closure photographs and defined as weight
visibility on the anterior eyelid (graded as not visible, mild visibility, moderate
visibility, or severe visibility). Weight migration was defined as the deviation of
the weight from its intended location (graded as yes or no). Upper eyelid contour
was scored based on eyelid position, eyelid crease, and eyelid symmetry (graded as
good, fair, or poor). Upper eyelid ptosis (graded as clinically significant or not
clinically significant) was assessed in photographs in which the patient's eyes were
open. Improvement of lagophthalmos was assessed in eyelid closure photographs and
defined as improvement of the inability to close the eyelid (graded as no, partial,
or complete).
Fig. 2 A female patient with complete right facial palsy and history of exposure keratitis
and bacterial corneal ulcer of the right eye. She underwent pretarsal implantation
of the traditional gold weight 3 years prior and experienced progressive implant exposure
and ptosis. The right photos show the 24-month result after implant exchange to the
supratarsal gold weight model.
Fig. 3 A female patient with complete left facial palsy for 2 years. The right photos show
the 24-month result after the primary implant of supratarsal gold weight model.
Descriptive statistics were used to evaluate the baseline characteristics of the patients.
Categorical data were described as frequencies and percentages. Continuous data with
a normal or approximately normal distribution were described using means and standard
deviations. Continuous data with skewed distributions were described using medians
and interquartile ranges. Comparisons of the primary outcomes, including eyelid contour,
weight prominence, weight migration, improvement of lagophthalmos, and eyelid ptosis,
between the two groups were performed using the generalized estimating equation model
adjusted for correlation between observations of outcomes from the same patient data
measured by five surgeons. The primary outcomes for each grader surgeon data were
compared using a binary regression model. Relative risks (risk ratios [RRs]) were
performed to express the effect size of the exposure group compared with the standard
group on outcomes related to the cohort study design. Statistical significance was
set at p < 0.05. All data were analyzed using Stata 14.0 (StataCorp. 2015).
Results
The medical records of the 30 patients included in this study were reviewed. Fifteen
patients underwent implantation of commercially available rectangular pretarsal weights
(PT group), whereas 15 patients underwent implantation of the newly designed elliptical
supratarsal weights (ST group). The average age of the patients was 60.8 ± 12 years,
and the majority were female (76%). The average duration of follow-up after surgery
was 28 months (range, 25–42 months). [Table 1 ] shows the baseline characteristics of the patients. All patients in the PT group
underwent primary implantation, whereas 7 of the 15 patients in the ST group underwent
revision surgery to correct weight exposure (4/7) and weight-induced ptosis (3/7).
The causes of facial palsy were surgically induced (27 patients), post-traumatic defects
(2 patients), and encephalitis (1 patient). [Fig. 4 ] shows the 12-month clinical outcomes of the PT and ST groups. The ST group had significantly
better eyelid contour (RR 3.16; 95% confidence interval [CI] 1.62–6.15; p = 0.001) than the PT group. The PT group had a significantly higher rate of weight
prominence (RR 1.74; 95% CI 1.13–2.7; p = 0.013), weight migration (RR 1.31; 95% CI 1.12–1.54; p = 0.001), and weight-induced eyelid ptosis (RR 2.36; 95% CI 1.21–4.59; p = 0.011) than the ST group. There was no statistically significant difference between
the two groups in improvement of lagophthalmos (RR 1.44; 95% CI 0.72–2.91; p = 0.303). The reoperative rate at 24 months was significantly higher in the PT group
compared with the ST group (53.3 vs. 13.3%; RR 2.00; 95% CI 1.15–3.49; p = 0.015). In PT group, reoperation was due to weight exposure (4/8), weight-induced
ptosis (3/8), and poor eyelid contour (1/8). In ST group, reoperation was due to weight
migration (2/15).
Fig. 4 Comparisons of the outcomes of both groups using a generalized estimating equation
model adjusted for correlation between observations from same patient (five observations
each).
Table 1
Baseline characteristics of the patients
Characteristics
Traditional rectangular pretarsal implantation; PT group (N = 15)
Newly designed elliptical supratarsal implantation;
ST group (N = 15)
Sex: female
12 (80.0%)
11 (73.3%)
Age (years), mean ± SD
60.7 ± 12.9
60.8 ± 11.0
Operated eye: right eye
10 (66.6%)
8 (53.3%)
Cause of facial palsy
Surgically induced
14 (93.3%)
13 (86.7%)
Infection
0 (0.0%)
1 (6.7%)
Trauma
1 (6.7%)
1 (6.7%)
Duration of follow-up (months)
Mean (Q1, Q3)
30 (26, 42)
27 (25, 30)
Abbreviation: SD, standard deviation.
Discussion
The design of gold weights and their materials, and the development of implantation
techniques, have gradually improved to minimize long-term complications. Implantation
in the pretarsal space or low placement of the eyelid weight was a standard lid loading
procedure; however, visibility and exposure of the implant are common unfavorable
outcomes of this technique.[3 ]
[4 ]
[11 ] With time, pretarsal weights become more apparent as orbicularis oculi muscle atrophy
occurs. Supratarsal implantation or high placement, which was introduced in 2004,
has become more popular because it induces less astigmatism and is associated with
less implant visibility as a weight is covered by more tissue planes.[8 ]
[9 ]
[10 ]
[12 ] In 2018, Allen has summarized the treatment options of the paralytic lagophthalmos
and concluded that a supratarsal position of the upper lid weight should be considered
rather than pretarsal placement.[2 ] The only disadvantages of supratarsal placement are more complex surgical steps
and more difficult weight sizing.
All commercially available implants are designed for pretarsal implantation of a Caucasian
eye with a trapezoid tarsal shape; thus, their dimensions are according to tarsal
height and width. The traditional weight dimensions are typically 4.5 to 6.6 mm wide,
9.9 to 18.7 mm long, and 0.6 to 1.0 mm thick. With pretarsal placement of the traditional
weight, visibility of the edge of the implant is more frequently observed in Asian
eye with sickle-shaped tarsus which is rounder and shorter.[7 ] Considering of the relatively large area beneath the levator aponeurosis, the new
gold weight, which has a larger surface area and is thinner than the traditional gold
weight, was specifically designed for supratarsal placement in Asian eye.
The ST group in the present study showed significantly better outcomes and had a lower
reoperation rate than the PT group. Moreover, the long-term complications recorded
in the ST group were comparable or even less than those reported in the previously
published data on platinum-based implants. However, the complete correction of the
lagophthalmos was less successful in ST group but did not reach statistical significance.
In previous studies, patients implanted with a platinum chain and platinum segment
had a reoperation rate of 22.2% at 12 months and 29.5% at 9.1 ± 9.2 months after primary
implantation, respectively.[13 ]
[14 ] Whereas the ST group in the present study had a reoperation rate of 13.3% at 24
months. It is universally accepted that platinum is a preferable material to gold
because it causes no allergic reactions and has a higher density. However, the limitations
of platinum are its higher cost and the complexity of its manufacturing process, which
hinders its use in many regions of the world. Platinum chains and segments are less
prominent and maintain good eyelid contour compared with platinum plates due to their
molding capability and weight distribution across the tarsus.[13 ]
[14 ]
[15 ]
[16 ] The study also explored the supratarsal postseptal placement of a platinum plate
in Asian eyes, which exhibited a low reoperative rate and yielded favorable aesthetic
outcomes.[17 ] Additional research is warranted to investigate the production of a new model employing
platinum and its placement beneath the levator aponeurosis.
This study has a few limitations. First, this study was conducted on East Asians,
whose eyelid anatomy is different from those of Caucasians and Hispanics. Modification
of the supratarsal weight may be needed when using the implants in patients of other
ethnicities. However, Caucasians and Hispanics possess a wider superior tarsal border
and post-levator space, which should theoretically be compatible with the supratarsal
model. Second, the number of cases reviewed in this study was too small to determine
the complications associated with the implantation of the new supratarsal gold weight.
Third, the superior results in ST group were also induced by the supratarsal implantation
technique, not solely the implant design. Finally, the retrospective design of this
study is another notable limitation. Long-term collation of the prospective data of
a larger number of patients implanted with this new weight is ongoing and the surgical
outcomes seem promising.
In conclusion, the newly designed elliptical supratarsal gold weight model evaluated
in the present study showed good functional and esthetic outcomes with a lower reoperation
rate in primary gold weight implantation and revision surgeries.
