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

International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors

BACKGROUND

Sinonasal neoplasms, whether benign and malignant, pose a significant challenge to clinicians and represent a model area for multidisciplinary collaboration in order to optimize patient care. The International Consensus Statement on Allergy and Rhinology: Sinonasal Tumors (ICSNT) aims to summarize the best available evidence and presents 48 thematic and histopathology-based topics spanning the field.

METHODS

In accordance with prior International Consensus Statement on Allergy and Rhinology documents, ICSNT assigned each topic as an Evidence-Based Review with Recommendations, Evidence-Based Review, and Literature Review based on the level of evidence. An international group of multidisciplinary author teams were assembled for the topic reviews using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses format, and completed sections underwent a thorough and iterative consensus-building process. The final document underwent rigorous synthesis and review prior to publication.

RESULTS

The ICSNT document consists of four major sections: general principles, benign neoplasms and lesions, malignant neoplasms, and quality of life and surveillance. It covers 48 conceptual and/or histopathology-based topics relevant to sinonasal neoplasms and masses. Topics with a high level of evidence provided specific recommendations, while other areas summarized the current state of evidence. A final section highlights research opportunities and future directions, contributing to advancing knowledge and community intervention.

CONCLUSION

As an embodiment of the multidisciplinary and collaborative model of care in sinonasal neoplasms and masses, ICSNT was designed as a comprehensive, international, and multidisciplinary collaborative endeavor. Its primary objective is to summarize the existing evidence in the field of sinonasal neoplasms and masses.

Endoscopic Endonasal Approach to the Pterygopalatine Fossa and Infratemporal Fossa: Comparison of the Prelacrimal and Denker's Corridors

BACKGROUND

Both the endoscopic transnasal Denker's and prelacrimal approaches provide surgical access to the pterygopalatine fossa (PPF) and infratemporal fossa (ITF).

OBJECTIVES

This study compares the potential maximum exposure of the PPF and ITF and quantifies the difference in surgical freedom via endoscopic Denker's and prelacrimal approaches.

METHODS

Six cadaveric specimens (12 sides) were dissected using a prelacrimal approach on one side and an endoscopic Denker's approach on the contralateral side. The contents of the PPF and ITF were sequentially exposed. Surgical freedom for each corridor was subsequently calculated.

RESULTS

This study confirms that both the prelacrimal and Denker's approaches provide adequate exposure of the PPF and ITF. The maximum exposure boundaries were similar for both approaches, including the middle cranial fossa superiorly, floor of the maxillary sinus inferiorly, zygomatic arch and temporomandibular joint laterally, and post-styloid space posteriorly. However, the data revealed a statistically significant difference (p < 0.05) regarding the surgical freedom of the prelacrimal (388.17 ± 32.86 mm²) and the endoscopic Denker's approaches (906.35 ± 38.38 mm²).

CONCLUSION

When compared with an endoscopic Denker's approach, a prelacrimal approach seems to achieve a similar extent of exposure (ie, visualization) of the PPF and ITF. Nonetheless, the endoscopic Denker's approach offers superior surgical freedom; thus, it is preferred for the management of complex lesions which requires increased instrument maneuverability with a 3- or 4-handed technique.

Radioanatomic Characteristics of the Posteromedial Intraconal Space: Implications for Endoscopic Resection of Orbital Lesions

BACKGROUND AND PURPOSE

Imaging is essential in the diagnostic work-up of patients with orbital lesions. The position of an orbital lesion relative to the inferomedial muscular trunk of the ophthalmic artery determines endoscopic resectability, anticipated technical difficulty, and patient morbidity. Although the inferomedial muscular trunk is not readily identifiable on preoperative imaging, we hypothesize that it is spatially approximate to the location where the ophthalmic artery crosses the optic nerve. Our aim was to determine whether the ophthalmic artery-optic nerve crosspoint anatomically approximates the inferomedial muscular trunk in a cadaver study and can be appreciated on imaging of known posteromedial orbital lesions.

MATERIALS AND METHODS

Dissection was performed on 17 fresh-frozen cadaver orbits to assess the relationship between the inferomedial muscular trunk and ophthalmic artery-optic nerve crosspoint. Retrospective review of imaging in 9 patients with posteromedial orbital lesions assessed posteromedial orbital compartment characteristics and the ability to locate the ophthalmic artery-optic nerve crosspoint.

RESULTS

In our cadaver study, the mean distance between the ophthalmic artery-optic nerve crosspoint and the inferomedial muscular trunk was 1.21 ± 0.64 mm. Retrospectively, the ophthalmic artery-optic nerve crosspoint was identifiable in 9/9 patients, whereas the inferomedial muscular trunk was not identifiable in any patient. Total or partial effacement of the posteromedial intraconal fat triangle was observed in 9/9 patients.

CONCLUSIONS

This study of neurovascular relationships within the posteromedial orbit demonstrates that the ophthalmic artery-optic nerve crosspoint closely approximates the inferomedial muscular trunk and can be seen in patients with posteromedial orbital lesions. Posteromedial intraconal fat effacement may help to localize these lesions. These findings may facilitate multidisciplinary communication and help predict lesion resectability and patient outcomes.

Prevalence of the prelacrimal recess in maxillary sinus and its medial bony wall dimensions

OBJECTIVE

To investigate the occurrence rate of the prelacrimal recess (PLR) and its medial bony wall dimensions based on the radiological analysis to help surgeons enhance the understanding of anatomic structures for the endoscopic prelacrimal recess approach.

METHODS

Cone-beam computed tomography images of 255 patients were evaluated retrospectively. The prevalence of the PLR in maxillary sinus was investigated and the thickness of its medial bony wall was measured and statistically assessed. Meanwhile, the width of the PLR was measured. The correlation between the width of the PLR and its medial bony wall thickness was assessed. The data were compared between the left side and right side, male and female.

RESULTS

The PLR was present in 82.5% of the maxillary sinus, with no significant differences between the left and right sides, as well as different gender groups. The mean thickness of the medial bony wall of the PLR was 2.84 ± 1.41 mm, without statistical difference between the left and right sides but significantly larger in males than in females. The mean width of the PLR was 4.62 ± 1.74 mm and it had a significant negative correlation with the thickness of the medial bony wall of the PLR.

CONCLUSION

A large individual variation exists in the anatomy of PLR, including its prevalence and dimensions of its medial bony wall. When considering the intranasal endoscopic prelacrimal recess approach, the surgeons should carefully evaluate the anatomical structure of the PLR preoperatively so as to minimize the risks of surgical complications.

Expanded exposure and detailed anatomic analysis of the superior orbital fissure: Implications for endonasal and transorbital approaches

This study aimed to ascertain the maximal exposure of the superior orbital fissure (SOF) afforded by combining endonasal and transorbital endoscopic approaches. Six cadaveric specimens (12 sides) were dissected using endonasal and transorbital endoscopic approaches to access the SOF. The order of the approaches was alternated in each specimen (eg, starting with an endonasal approach in one side followed by a transorbital exposure and reversing the order on the contralateral side). Maximal exposure of the SOF and its contents for individual and combined approaches were explored. The endonasal corridor provided adequate access to the inferomedial 1/3 of the SOF and including the proximal segments of cranial nerves (CN) III, V₁ and VI. A transorbital approach was superior accessing the superolateral 2/3's of the SOF, including the superior ophthalmic vein, lacrimal nerve, and distal segment of the CN VI at the lateral aspect; the nasociliary nerve and divisions of CN III centrally; and the frontal nerve and CN IV at the dorsal aspect of levator palpebrae superioris. This study suggests that a combined endonasal and transorbital exposure of the SOF may be advantageous to address lesions in this challenging region.

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

OBJECTIVE

This study aimed to assess the outcomes of a prelacrimal recess approach assisted middle meatal antrostomy in the management of hard to reach maxillary sinus pathologies.

METHOD

Twenty-five patients with maxillary sinus pathology underwent prelacrimal recess approach assisted middle meatal antrostomy (with a prelacrimal recess width of more than 3 mm). Patients were prospectively evaluated using both the Arabic version of the Sino-Nasal Outcome Test-22 and nasal endoscopy at least 6 months post-operatively.

RESULTS

Our study included 25 maxillary sinuses (13 with antrochoanal polyps, 10 with maxillary fungal ball and 2 with a migrated part of a tooth). At a mean follow-up period of 10.9 months, all patients showed significant improvement in total mean Sino-Nasal Outcome Test-22 score. There was recurrence of one case with antrochoanal polyp and two cases with asymptomatic synechia. Injury to the nasolacrimal duct was not reported.

CONCLUSION

A prelacrimal recess approach assisted middle meatal antrostomy is a reliable and safe technique to manage pathologies in hard to reach regions within the maxillary sinus.

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

BACKGROUND

Endoscopic transethmoidal and prelacrimal approaches can access the medial intraconal space (MIS).

OBJECTIVE

This study aimed to compare advantages and drawbacks of these two approaches, and to explore their appropriate indications for management of lesions at various locations within the MIS.

METHODS

Six injected cadaveric specimens were dissected using an endonasal approach performing a transethmoidal approach on one side and a prelacrimal approach on the contralateral side. The MIS was divided into three Zones: Zone 1 was defined as the area above the superior border of the medial rectus muscle (MRM), Zone 2 as the area between the MRM and the optic nerve, and Zone 3 as the area below the inferior border of MRM. The exposure provided by these two approaches to various Zones within the MIS was assessed and compared.

RESULTS

The average height of Zone 1 to 3 was 10.35 ± 0.45 mm, 11.07 ± 0.59 mm, and 6.53 ± 0.59 mm, respectively. Both approaches provided adequate exposure of Zone 2 and 3; however, the prelacrimal approach provided direct exposure of the posterosuperior aspect of Zone 2 without retraction of MRM. Retraction of MRM was unavoidable using a transethmoidal approach to enhance further exposure. Access to Zone 1 was adequately achieved through the corridor between superior oblique muscle and MRM via a transethmoidal corridor.

CONCLUSION

Conceptualizing the MIS into the three aforementioned Zones seems beneficial to select the optimal approach for lesions restricted to each specific Zone. Both the transethmoidal and prelacrimal approaches provide adequate exposure for select lesions in the MIS.

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

Background

The anterolateral triangle enclosed by the foramen rotundum and foramen ovale constitutes part of the floor of the middle cranial fossa (MCF).

Objective

To assess the feasibility of a transnasal prelacrimal approach for accessing the floor of MCF via an anterolateral triangle corridor and to determine the extent of maximal exposure while safeguarding neurovascular structures.

Methods

A transnasal prelacrimal approach was performed in 5 cadaveric specimens (10 sides). Following the identification of foramen rotundum and foramen ovale, the bony ridge between 2 was drilled to expose the MCF. The temporal lobe dura was then elevated laterally, and the distances from foramen ovale to the respective borders of the area of the MCF window were measured using a surgical navigation device.

Results

The MCF was exposed with a 0° scope in all specimens also exposing significant landmarks including the middle meningeal artery, greater superficial petrosal nerve, superior petrous sinus, and arcuate eminence. Average distances from foramen ovale to the anterior, posterior, and lateral exposed borders were 22.86 ± 1.87 mm, 27.24 ± 0.94 mm, and 24.23 ± 1.61 mm, respectively. The average area of exposed MCF window was 554.12 ± 60.22 mm2. Preservation of vidian nerve, greater palatine nerve, lateral nasal wall, and nasolacrimal duct was possible in all 10 sides.

Conclusion

It is feasible to access the floor of MCF via an endoscopic transnasal prelacrimal approach with seemingly low risk.

Intraconal Anatomy of the Anterior Ethmoidal Neurovascular Bundle: Implications for Surgery in the Superomedial Orbit

Background

The anterior ethmoidal artery (AEA) branches from the ophthalmic artery in the superomedial intraconal space. The feasibility of management of lesions arising from the superomedial intraconal space via an endoscopic endonasal approach has not been sufficiently explored.

Objective

To yield a detailed anatomic description of the anterior ethmoidal neurovascular bundle and its variants to serve as the foundation for possible management of lesions in the superomedial intraconal space.

Methods

Eight cadaveric specimens (16 sides) were dissected using an endonasal approach, tracing the AEA proximally through the superomedial intraconal space. Furthermore, the anatomy of adjacent structures was noted, and distances from the anterior ethmoidal foramen to the origin of the AEA at the ophthalmic artery were measured.

Results

Supraorbital cells were found in 13/16 sides (81.25%), and a bony dehiscence of the anterior ethmoidal canal was observed in 5/16 sides (31.25%). The nasociliary nerve, ophthalmic artery, superior division of the oculomotor nerve, superior rectus muscle, and levator palpebrae superioris were routinely identified in the superomedial intraconal space. The AEA passed through a corridor between the medial rectus and superior oblique muscles after arising from the ophthalmic artery (lateral to the foramen) in all specimens. The average distance from its origin to the anterior ethmoidal foramen was 5.19 ± 0.98 mm.

Conclusion

Anatomically, it is feasible to access the superomedial intraconal space via an endoscopic endonasal approach. This study provides the anatomical basis for procedures in the superomedial intraconal space.

Endoscopic prelacrimal approach to lateral recess of sphenoid sinus: feasibility study

BACKGROUND

Various pathologies, including cerebrospinal fluid leaks and meningoencephaloceles, may arise in the lateral recess of the sphenoid sinus (LRSS), which may be accessed via an endonasal transpterygoid approach. The objective of this study was to evaluate the feasibility of accessing the LRSS via an endoscopic prelacrimal approach. Furthermore, we hypothesized that this approach may protect the pterygopalatine ganglion and vidian nerve.

METHODS

Five cadaveric heads (9 sides) with a well-pneumatized LRSS were identified and an endonasal prelacrimal approach was performed. The infraorbital nerve, at the orbital floor, served as a critical landmark. After identification of the foramen rotundum at the pterygoid base, the vascular compartment of the pterygopalatine fossa and the pterygopalatine ganglion were displaced inferomedially and superomedially, respectively. Drilling of the bone inferomedial to the foramen rotundum allowed entry into the LRSS.

RESULTS

The average distances from the prelacrimal window to the pterygoid base and the posterior wall of the LRSS were 6.22 ± 0.39 cm and 7.16 ± 0.50 cm, respectively. The average areas of the bony prelacrimal window and pterygoid base window were 4.33 ± 0.32 cm² and 0.73 ± 0.10 cm² , respectively. The LRSS could be accessed using a 0-degree endoscope, and pterygopalatine neurovascular structures, including the pterygopalatine ganglion and vidian nerve, could be preserved on all 9 sides.

CONCLUSION

Our findings suggest that an endonasal prelacrimal approach provides a reasonable alternative to access the LRSS while preserving the vidian nerve and pterygopalatine ganglion.