Anatomical variations of the levator palpebrae superioris, including observations on its innervation and intramuscular nerves' distribution pattern

A novel hybrid BonT-A and hyaluronic acid cannula-based technique for eyelid ptosis and periorbital rejuvenation

BACKGROUND

Eyelid ptosis is characterized by an inferior displacement of the upper eyelid when the eye assumes its primary position. Besides its aesthetic implications, ptosis can also adversely affect visual acuity.

OBJECTIVE

This study aimed to evaluate the simultaneous administration of IncobotulinumtoxinA (IncoBonTA) and hyaluronic acid effect in eyelid ptosis and ocular rejuvenation.

METHODS

A novel, non-surgical technique for eyelid ptosis management involving IncoBonTA and hyaluronic acid the co-administration within a single syringe, and applied using a cannula.

RESULTS

The dual action of IncoBonTA and hyaluronic acid in conjunction with the exact injection sites approaches improves overall aesthetic outcomes but also optimizes the restoration of eyelid functionality in palpebral ptosis.

CONCLUSIONS

The functional balance achieved among the contributory muscles-primarily the orbicularis oculi (OO) and its antagonists, the frontal muscle and levator palpebrae superioris (LPS), yields to both, cosmetic and functional.

Accessory Muscles Associated With the Levator Palpebrae Superioris Muscle in 100 Cadavers

PURPOSE

This study aimed to determine the variations of the levator palpebrae superioris muscle and to reveal its morphological features.

METHODS

This study conducted on 100 adult orbit cadavers in the Department of Anatomy, Istanbul University, used an exploratory, descriptive research design. The anatomical and morphological variations of the levator palpebrae superioris muscle and its relationship with the superior ophthalmic vein were evaluated.

RESULTS

Variations of levator palpebrae superioris muscle were discovered in 11 of 100 orbits. Single (9%), double (1%), and triple (1%) accessory muscle slips were observed. The origin of accessory muscle slips showed variation as the accessory muscle slips originated either from the proximal or distal half of the levator palpebrae superioris muscle. Also, the insertions of accessory muscle slips were variable, as they were inserted into levator aponeurosis, trochlea, lacrimal gland, lateral orbital wall, or the fascia of the superior ophthalmic vein.

CONCLUSIONS

Accessory muscles associated with levator aponeurosis were found in a significant proportion of cadavers. These muscles may cause confusion in orbital surgery and should be taken into account during surgical planning and orientation in the superior orbit.

Postoperative Visual Outcome: Sling procedure with prolene sutures in children with simple congenital ptosis

Objective:

To assess the visual outcome after sling procedure using prolene sutures in children with simple congenital ptosis.

Methods:

A descriptive case series study was performed in the Department of Ophthalmology of Jinnah Post Graduate Medical Centre, for a duration of six months in which 20 patients aged 3-10 years were selected with either unilateral or bilateral congenital ptosis. They were thoroughly examined and visual acuity and degree of ptosis were measured pre-operatively. Frontalis sling surgery was performed using prolene sutures on all patients after which their visual acuity and degree of ptosis were measured once again after three months post-operatively. Data were analyzed using SPSS version 20.0. For qualitative variables, frequency and percentages were calculated. Mean and Standard deviation was commutated for the quantitative variable.

Results:

The mean age of the patients was 8.15±1.75. 11 (55%) male and 9 (45%) female participants were included in the study. Visual acuity improved in all the patients with all the patients attaining a visual acuity of 6/6 (n=12, 60%), 6/9 (n=7, 35%), and 6/12 (n=1, 5%). The degree of ptosis post-operatively was not found in any patient either.

Conclusion:

Sling procedure helped in eliminating ptosis and improved visual acuity in patients with simple congenital ptosis.

Influence of dental occlusion on oculomotory function-A pilot study

The aim of this study was to examine the interaction between the oculomotory system and the stomatognathic system based on morphofunctional relationships between the corresponding cranial nerves, their core areas and the reticular formation as a "link" by means of optometric examinations. Test subjects (N = 100) were prospectively recruited and divided into two groups: a young-age (N = 53, age 6-16 years) and old-age group (N = 47, 23-78 years). We determined the horizontal range of convergence and divergence as well as the near convergence point. These optometrically measured parameters were recorded in both groups in the resting position, at maximal mouth opening and with bite-blocking via tin foils (0.5 mm and 1 mm), which were inserted occlusally of the first lower left molar. All oculomotory parameters were significantly altered by bite manipulation and maximal mouth opening. These effects could be observed regardless of age and gender and thus suggest an interaction between eye movement and the orofacial complex. Subjects with asthenopic symptoms showed no different reactions compared to healthy subjects. For a final statement on the correlation between the oculomotory and stomatognathic system, further investigations are necessary. An interdisciplinary cooperation between the different subject areas is recommended for further studies.

Examination of the Annular Tendon (Annulus of Zinn) as a Common Origin of the Extraocular Rectus Muscles: 2. Embryological Basis of Extraocular Muscles Anomalies

Purpose

Many reports have described anomalous connections of the superior rectus (SR) with other extraocular rectus muscles, in which additional heads of the other three rectus muscles likely provided the connections. We examined how these connections are established during fetal development.

Methods

We analyzed paraffin-embedded horizontal sections from 25 late-stage fetuses. Horizontal sections are best suited for understanding the mediolateral relationships of muscle origins.

Results

We confirmed a common tendinous origin of the lateral rectus (LR), inferior rectus (IR) and medial rectus (MR) muscles that was separated from the SR origin. Notably, eight fetuses (32%) had tendinous or muscular connections between the SR and other rectus muscles that had one of four morphologies: (a) a thin tendon from the SR to the common tendon of the three rectus muscles (2 fetuses), (b) a thin tendon to the LR (one fetus), (c) a thin tendon to the inferior rectus muscle origin (two fetuses), and (d) SR muscle fibers arising from an additional head of the LR (three fetuses).

Conclusions

The SR seemed to issue a thin tendon that passed along the inferior or lateral side of the oculomotor nerve. Conversely, the LR and inferior rectus muscle were likely to carry a supernumerary bundle that reached the SR. The accessory head of the medial rectus muscle showed a stable morphology in that it seemed to also provide an anomalous double head. However, the presence of an accessory head in the LR was rare. In contrast with our previously published diagram of the orbital apex, the accessory head of the medial rectus muscle passed along the lateral side of the superior oblique.

Comparison of the Superior and Inferior Rectus Muscles in Humans: An Anatomical Study with Notes on Morphology, Anatomical Variations, and Intramuscular Innervation Patterns

A comparison of the superior and inferior rectus muscles was performed to determine whether they have similar structures and innervation attributable to their participation in the same type of, although antagonistic, eye movements. The study was conducted on 70 cadaveric hemiheads, and the anatomical variations in the superior and inferior rectus muscles were assessed. Sihler's whole mount nerve staining technique was used on 20 isolated superior and 20 isolated inferior rectus muscle specimens to visualize the intramuscular distribution of the oculomotor nerve subbranches. In two cases (~2.8%), variant muscular slips were found that connected the superior and inferior rectus muscles. In 80% of cases, muscular branches arising directly from the inferior branch of the oculomotor nerve innervated the inferior rectus muscle, while in 20% of cases, the nerve to the inferior oblique muscle pierced the inferior rectus muscle and provided its innervation. In 15 of 70 specimens (21.4%), a branch to the levator palpebrae superioris muscle pierced the superior rectus muscle. The distance between the specific rectus muscle's insertion and the anterior-most terminations of the nerves' subbranches with reference to the muscle's total length ranged from 26.9% to 47.2% for the inferior rectus and from 34.8% to 46.6% for the superior rectus, respectively. The superior rectus muscle is slightly longer and its insertion is farther from the limbus of the cornea than is the inferior rectus muscle. Both muscles share a common general pattern of intramuscular nerve subbranches' arborization, with characteristic Y-shaped ramifications that form the terminal nerve plexus located near half of the muscles' length. Unexpected anatomical variations of the extraocular muscles may be relevant during orbital imaging or surgical procedures.