Anatomic characteristics of supraorbital and supratrochlear nerves relevant to their use in corneal neurotization

Abstract

Background Corneal denervation can lead to opacification and blindness. A new treatment technique, surgical corneal neurotization, transfers healthy donor nerve, (most commonly contralateral supratrochlear or supraorbital) to the affected limbus to prevent corneal destruction and improve healing potential of the cornea following insult. We examine gross and histomorphometric anatomy of the supratrochlear and supraorbital nerves relevant to their use in corneal neurotization. Methods For each of nine adult cadaver heads, bilateral supraorbital and supratrochlear nerves were dissected from the supraorbital rim to the anterior hairline. The following data were recorded for each nerve: exit from the orbit through a notch versus foramen; horizontal distance from midline at the supraorbital rim; and distance from orbital exit to first branching point. Samples of all left supraorbital and supratrochlear nerves were obtained at the level of the supraorbital rim and at points 3 cm and 6 cm distally for histomorphometric analysis. Myelinated axon counts were determined for each sample. Results Four supraorbital foramina, 14 supraorbital notches, two supratrochlear foramina, and 15 supratrochlear notches were identified. Average supraorbital and supratrochlear distances to midline were 26.5 mm and 21 mm respectively. Average myelinated axon counts for both nerves were greater at the orbital rim (supraorbital: 6018, supratrochlear: 2533) than at 6 cm distally (supraorbital: 1621, supratrochlear: 1112). Conclusions Anatomic dissection shows relative close approximation of the supraorbital and supratrochlear nerves, with a high proportion of both nerves exiting the orbit through foramina. The supraorbital nerve at the orbital rim contains the greatest number of myelinated axons.

Anatomical Variations of the Supraorbital and Supratrochlear Nerves: Their Intraorbital Course and Relation to the Supraorbital Margin

“…Knowledge of the anatomy of the supraorbital and supratrochlear nerves has become more important in connection with the development of modern diagnostic and therapeutic methods and surgical techniques. This applies to procedures such as the anterior orbital approach, corneal neurotization, fronto-glabellar reconstruction flap, supraorbital injection, surgical treatment of migraine headaches, upper eyelid surgeries (e.g., blepharospasm surgery or direct browplasty) and any procedure requiring scalp or forehead incisions such as a forehead lift or endoscopic facial techniques [3–13]. Anatomic characteristics of supraorbital and supratrochlear nerves may also be relevant due to their use in eyeblink conditioning [14] or neurostimulation for preventing and treatment of migraine and cluster headaches [15–17].…”

Determination of Current Flow Induced by Transcutaneous Electrical Nerve Stimulation for the Treatment of Migraine: Potential for Optimization

“…Supratrochlear and supraorbital nerve compartments were manually created, guided by BioDigital Human, an interactive 3D software platform for visualizing human anatomy ( 14 ). In addition, a histomorphometric anatomical study was used for overall verification of the anatomical location of the nerve compartments ( 15 ).…”

Clinical Outcomes and Patient Satisfaction After Corneal Neurotization

“…The SON has been found to have greater than double the number of axons found in the STN and less donor site morbidity on transection compared with ION. 30 Therefore, end-to-end coaptation was performed for SON and STN and end-to-side neurorrhaphy for ION. In all but 1 case, the host nerve was harvested using minimally invasive techniques with or without endoscopic guidance as previously described.…”