Expanding the limits of endoscopic intraorbital tumor resection using 3-dimensional reconstruction

Minimally Invasive 360-Degree Approach to Intraconal Orbital Tumors

PURPOSE

To evaluate clinically the efficacy of 360-degree minimally invasive endoscopic surgery in patients with orbital intraconal tumors.

DESIGN

Retrospective interventional case series.

METHODS

A series of consecutive patients with orbital intraconal tumors were treated with minimally invasive surgery using an endonasal endoscopic approach or an anterior endoscopic orbitotomy over a 5-year period between January 2015 and January 2020 at the National Institute of Oncology and Radiobiology of Cuba.

RESULTS

In 22 patients, the mean age was 52.3 ± 11 years (range 18-71 years) with a female to male ratio of 1.8:1. Visual loss was present in 3 patients and proptosis was present in 19 patients. The most common diagnosis was cavernous hemangioma (72.7%) followed by orbital sheet meningioma (9.1%). The lower-inner (type II) location was the most usual, followed by the lower-outer (type IV). A gross total resection was achieved in 95.5% of patients. In only 1 case with an orbital pseudotumor was the resection subtotal because of the fibrous consistency, irregularity, and adherences to the medial rectus muscle. All patients with visual loss improved to normal visual function after surgery at follow-up and orbital proptosis recovered in all patients with these symptoms. Both immediate and long-term morphologic and aesthetic results were good in all patients.

CONCLUSION

The minimally invasive 360-degree surgical approach with a full endoscopic visualization can be safe and efficient in patients with select orbital intraconal tumors. Optic nerve location constitutes the main aspect in the surgical approach selection. A large case series is necessary to standardize this surgical philosophy.

The Endoscopic Transnasal Approach to Orbital Tumors: A Review

Historically, surgical access to orbital tumors has required a transcutaneous, transconjunctival or transcranial approach. Resection of orbital tumors is notoriously challenging due to the surrounding dense network of critical structures in a confined bony cavity. Advances in endoscopic endonasal surgery, initially used for sinonasal and skull base conditions, have allowed for expansion of its applications beyond the sinorbital interface. In the past decade, the evolution of techniques has enabled a purely endoscopic, minimally invasive approach to medially located orbital pathology with good outcomes. With experience and multidisciplinary collaboration between orbit and rhinologic surgeons, this has expanded to allow for a safe and effective transnasal approach to nearly all regions of the orbit with or without assistance from the orbital side. This review summarizes the relevant anatomy, variations of surgical approaches, and literature regarding outcomes of the endoscopic endonasal approach to orbital tumors.

Endoscopic Endonasal Approach for Intra- and Extraconal Orbital Pathologies

Endoscopic endonasal approaches offer an important alternative in the management of posterior inferomedial orbital pathology. Beginning with endoscopic orbital decompressions for Graves' disease, the endonasal corridor for the management of intra- and extraconal pathologies has continued to evolve. Endonasal removal of orbital cavernous hemangiomas is well described in the literature; however, many other benign and malignant pathologies of the medial orbit can be accessed through this approach. Advantages of the endonasal approach include improved visualization and decreased manipulation of orbital contents in the medial and posterior orbit. Additionally, for tumors that extend from the paranasal sinuses into the orbit, this corridor may be ideal for concurrent management. The current literature for this approach will be reviewed including the oncologic results, complications, limitations, and reconstructive needs along with pertinent anatomy. In addition, data from our own institution will be reviewed.

Endoscopic endonasal intraconal orbit surgery

Endoscopic endonasal orbital surgery is evolving. With increasing knowledge, expertise, and technology, the historical limits of the endonasal endoscopic approach to the orbit have been redefined. This review discusses the clinical presentation and etiology, and highlights the pertinent anatomy, and discusses the diagnostic workup and surgical approach to orbital tumors and post-operative care. The role of the multidisciplinary team is not to be underestimated. The introduction of a classification system to ensure standardization of technical difficulty and outcome data will assist with international collaboration and further consolidate our attainment of knowledge in this developing field.

Development of a Modular Cadaveric Endoscopic Orbital Surgery Model

Introduction

Endoscopic orbital surgery requires the acquisition of unique skill set including endoscopic bimanual dissection of intra/extraconal lesions adherent to orbital fat and neurovascular structures. Our goal was to develop a modular cadaveric model used to train surgeons to resect orbital pathology within any desired orbital compartment.

Methods

Expansile superabsorbent polymer (SAP) beads (2 mm) were soaked in Omnipaque™ (Iohexol) solution for 15 minutes prior to transcaruncular orbital implantation using 10-gauge angiocath. Insertion depth was designed to implant beads in predetermined intraconal compartments corresponding to established orbital tumor stages. Beads were left to expand in situ over a period of 1 to 5 hours. Computed tomography scans were performed using the FUSION image guidance protocol. Model utility and learning curves were assessed by quantifying resection time over 8 sequential attempts.

Results

All 24 beads were successfully implanted in 8 orbits corresponding to CHEER stage II to IV lesions (n = 3 per orbit). Beads expanded from 2 mm to an average of 5.2 mm within 1 hour. During expansion, the beads interpolated into the adjacent fascia similar to in vivo tumors. Average insertion time was 5:53 minutes per orbit (range, 3:24–10:33 min) and average time to bead identification was 10:47 minutes. Across all beads, dissection times decreased in a nonsignificant manner over 8 consecutive attempts.

Conclusion

The directed implantation of expansile SAP beads in this cadaveric model accurately replicates the approach, identification, and resection of isolated orbital lesions. This orbital model can assist the endoscopic surgical team to develop further knowledge and technical skill sets to approach orbital lesions. Further ongoing studies to validate this model are currently underway.