Transnasal prelacrimal approach to the inferior intraconal space: a feasibility study

Abstract

BackgroundEndonasal access to the inferomedial and inferolateral intraconal space via the orbital floor has not been reported. The primary purpose of this study was to assess the feasibility of accessing the inferior intraconal space through the orbital floor via a transnasal prelacrimal approach. Secondarily, it aims to highlight anatomical relationships of neurovascular structures in this space, as a requirement to prevent complications.MethodsSix cadaveric heads (12 sides) were dissected using a transnasal prelacrimal approach. The orbital floor, medial to the infraorbital canal, was removed and the periorbita opened to expose the inferior rectus muscle. The inferomedial and inferolateral intraconal space was accessed alongside the medial and lateral border of inferior rectus muscle, respectively. Various anatomical relationships of adjacent neurovascular structures were recorded, and the distances among the recti muscles and optic nerve were also measured.ResultsThe infraorbital nerve is located at the inferolateral aspect of inferior rectus muscle. In the inferomedial intraconal space, we identified the inferomedial muscular trunk of the ophthalmic artery, optic nerve, and branches of the oculomotor nerve; whereas the inferolateral intraconal space contained the inferolateral muscular trunk of ophthalmic artery, branches of the oculomotor and nasociliary nerve, and abducens nerve. Distances from the medial, inferior, and lateral recti muscles to the optic nerve were (mean ± standard deviation) 4.70 ± 1.18 mm, 5.60 ± 0.93 mm, and 7.98 ± 1.99 mm, respectively. Distances from the inferior rectus muscle to the inferior borders of medial and lateral recti muscles were 4.45 ± 1.23 mm and 8.77 ± 1.80 mm.ConclusionIt is feasible to access the inferior intraconal space through the orbital floor via a transnasal prelacrimal approach. The access may be subdivided into inferomedial and inferolateral corridors according to the entry point at the medial or lateral border of the inferior rectus muscle. Neurovascular structures in the inferior intraconal space are visualized directly, which should enhance their preservation.

The Anterolateral Triangle: Implications for a Transnasal Prelacrimal Approach to the Floor of the Middle Cranial Fossa

“…19 Both the foramen rotundum and foramen ovale could be sufficiently exposed via a transnasal prelacrimal approach. [12][13][14][15][16][17] Therefore, the distal aspect of the anterolateral triangle, which is enclosed by V 2 (foramen rotundum) and V 3 (foramen ovale), providing a direct avenue and the rationality for exposure of the floor of MCF via a prelacrimal approach. 5 The average area of the MCF window was 554.12 AE 60.22 mm 2 , which was adequate for maneuverability into the floor of MCF through this corridor.…”

“…28,29 Despite the average area of the bony prelacrimal window was 441.84 AE 37.75 mm 2 after partial removal of the medial and anterior walls of the maxillary sinus, the authors recognized that it was still a challenge to simultaneously manipulate the rod-lens endoscope and 2 instruments through the prelacrimal window. 16 The addition of an anterior antrostomy such as a Caldwell-Luc approach or any other variant, including expanding the prelacrimal window laterally, could obviate the restriction for instrumentation. 30 However, removal of the piriform crest and anterior face of the maxillary sinus, and displacement of the nasolacrimal duct as required to facilitate or expand the prelacrimal corridor, may carry the risk of postoperative piriform aperture stenosis, alar constriction, and epiphora.…”

“…13,14 Moreover, previous cadaveric studies demonstrated that a transnasal prelacrimal approach, with preservation of lateral nasal wall, nasolacrimal duct, and neurovascular bundles in pterygopalatine fossa, is a less invasive technique than both the transpterygoid EEA and the transantral approach. [15][16][17] We therefore hypothesized that in order to decrease the associated comorbidities, the floor of MCF could be accessed via a transnasal prelacrimal approach.…”

Third window approach assisted middle meatal antrostomy: prospective cohort study of the two ports technique in management of hard to reach maxillary sinus pathology

“…A study by Li et al 17 included dissection of five cadaveric heads and demonstrated the role of the prelacrimal recess as direct access from the posterolateral maxillary sinus to the lateral recess of the sphenoid sinus, utilising the infra-orbital nerve as a landmark to preserve the vidian nerve and pterygopalatine ganglion. In another cadaveric study by Li et al, 18 the prelacrimal recess was used to access the inferior intraconal space through the orbital floor.…”

Endoscopic Endonasal Approaches to the Medial Intraconal Space: Comparison of Transethmoidal and Prelacrimal Corridors

“…15 Others have suggested the use of endonasal approaches to the orbit. [16][17][18] On previous cadaveric studies, partial resection of the orbital floor via a transnasal prelacrimal approach provided a corridor to access the inferior intraconal space, 16,17 and a transethmoidal approach was advocated to access the superomedial intraconal space. 18 Although both the transethmoidal and prelacrimal approaches can access the inferomedial intraconal space, technical nuances, advantages and drawbacks for each approach have not been sufficiently explored.…”