Clinical trial NCT03396627: Müller's Muscle as a New Proprioceptive Organ
Official title: Müller's Muscle as a New Proprioceptive Organ Evidence From Immunohistochemical Staining and Electron Microscopy to Verify That the Upper Eyelid Müller's Muscle Contains Proprioceptive Innervation for Reflexive Correction of Eyelid Position
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Eyelid Movement Disorders
Eyelid Ptosis Congenital
Keywords: eyelid
Muller
Lead sponsor: Sheba Medical Center
Sponsor class: OTHER_GOV
First posted: 2018-01-11
Enrollment: 50
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: patients over 18 years old undergoing Müllerectomies

Brief summary: Objectives: Upper eyelid retraction was believed to be maintained solely by voluntary contraction of the levator palpebrae superioris (LPS) and frontalis muscles, together with involuntary contraction of the sympathetically innervated Müller's muscle (MM). However, several studies have suggested that the LPS also undergoes involuntary contractions, and that a visual stimulus may not be the only trigger for frontalis muscle contractions. Recent studies hypothesized that the MM contains proprioceptive neuronal structures, which elicit involuntary LPS muscle contraction by the mesencephalic trigeminal nucleus via a continuous stretch reflex. We aim to identify proprioceptive structures in MM by means of histological examinations.

Methodology: Prospective study. Collaboration of oculoplastics, ophthalmologists and a neuroanatomy specialist in Sheba Medical Center. 50 fresh MM specimens from patients undergoing Müllerectomies will undergo histologic examinations, including immunohistochemical staining and light and electron microscopy.

Significance: Identification of proprioceptive structures in MM will be the first evidence-based proof of a proprioceptive mechanism in the eyelid. This might have a significant impact on future surgical management of eyelid procedures. Comprehensive understanding of the mechanisms underlying eyelid function is especially important in the management of children with ptosis who may have coexisting amblyopia.

Detailed description: The investigators' goal is to find proprioceptive neuronal structures in Müller's muscle (MM). The investigatorswill recruit 50 MM specimens of patients diagnosed with either unilateral or bilateral ptosis who were referred to undergo a posterior approach surgical correction (MMCR). In this surgical approach, the proximal part of MM is removed between the levator palpebrae superioris muscle and the tarsus of the upper eyelids. The excised tissue is generally not used but simply discarded. For study purposed, the investigators will obtain the patients' consent to save these tissues and carry out histologic examinations of the samples. No change in the surgical procedure or the following management will be needed.

Eligibility criteria: Inclusion Criteria:

* specimens from patients undergoing Müllerectomies

Exclusion Criteria:

* small specimens (\<1 cm length and width)

Primary outcomes:
measure: presence of proprioceptive organs in the muller muscle
timeFrame: 2 years
Secondary outcomes:
Other outcomes:
Locations:
city: Ramat Gan
country: Israel
facility: Sheba_Medical_Center
Study officials:
References:
citation: Ben Simon GJ, Blaydon SM, Schwarcz RM, Nakra T, Goldberg RA, McCann JD. Paradoxical use of frontalis muscle and the possible role of botulinum a toxin in permanent motor relearning. Ophthalmology. 2005 May;112(5):918-22. doi: 10.1016/j.ophtha.2005.01.004.