Quantitative study on endoscopic endonasal approach to the posterior sino-orbito-cranial interface: implications and clinical considerations

Graves-Basedow ophthalmopathy surgical approaches: Open vs Endoscopic

Graves-Basedow's disease (GBD) is an autoimmune pathology that affects the thyroid and is characterized by the presence of goiter, hyperthyroidism, ophthalmopathy, and dermopathy. Graves-Basedow ophthalmopathy (GBO) is a set of inflammatory and infiltrative alterations of the orbital tissue that affects 40-90% of subjects suffering from GBD. Our study aims to investigate the differences in the clinical outcomes of patients treated with two different techniques: the classic open and the more modern endoscopic. A retrospective clinical study was carried out from the year 2011 until the year 2020 to evaluate the clinical outcomes of two different surgical techniques for the treatment of GBO. Eighteen patients were given surgical indications, 12 males and 6 females aged between 37 and 69 years (average age 48.5 years), for a total of 36 orbits. From the year 2011 to the year 2014, all patients were treated with the open orbital decompression technique; from 2015 onwards, patients were subjected to orbital decompression with the endoscopic transnasal approach. Pre- and postoperative ophthalmometry, reduction of proptosis, and reduction of oculo-orbital index were compared for the two techniques. As evidenced by the statistical analysis carried out on the sample before and after surgical treatment, there is a statistically significant difference between ophthalmometry and the Oculo-Orbital Index (IOO) values; this indicates that surgical orbital decompression with two walls (floor and medial wall) is effective in reducing exophthalmos. The positive result is also confirmed by the reduction of proptosis, measured in millimeters, averaging 1.7 mm. In the analysis of data relating to the two different patient groups, treated respectively with endoscopic orbital decompression (Technique 1) and classical open orbital decompression (Technique 2), the results obtained show that there is no statistically significant difference between the results of the two techniques. Therefore, the choice of surgical approach is at the discretion of the surgeon. It is our opinion that orbital decompression with the endoscopic transnasal technique should be an absolute indication in all patients who have clinical and radiographic signs of involvement of the optic nerve at the orbital apex (crowded apex syndrome) thanks to the ability of this technique to add and decompress the optical channel at the apex. For all other patients with GBO, the endoscopic technique of orbital decompression can be indicated as a first-line surgical approach considering the absence of skin scars and the best aesthetic results.

Endonasal Endoscopic Anatomy of the Orbito-Cavernous-Pterygopalatine Interface: Multilayer Anatomical Description and Landmarks to Define the Limits of the Compartments

BACKGROUND

Despite growing interest in the endoscopic endonasal approach (EEA) to the medial orbital apex (OA), a comprehensive description of the multilayer topology lying at the intersection of the regional compartments is missing.

METHODS

An EEA to the OA, pterygopalatine fossa, and cavernous sinus was performed in 20 specimens. A 360° layer-by-layer dissection was performed taking into consideration relevant anatomical aspects of the interface and documented with 3-dimensional technologies. Endoscopic landmarks were analyzed to provide an outline of the compartments and identify critical structures. Additionally, the consistency of a previously described reference called orbital apex convergence prominence was analyzed and a method to identify its position was introduced.

RESULTS

The orbital apex convergence prominence was an inconsistent finding (15%). However, a craniometric method introduced in this study proved to be reliable to reach the orbital apex convergence point. Additional structures such as the sphenoethmoidal suture and a 3-suture junction (sphenoethmoidal-palatoethmoidal-palatosphenoidal) helped to identify the posterior limit of the OA and define a keyhole to access the compartments of the interface. We defined the bone limits of the "optic risk zone," an area where the optic nerve is more susceptible to damage. Furthermore, an orbital fusion line (periorbita-dura-periosteum) was identified and divided into 4 segments according to adjacent structures: optic, cavernous, pterygopalatine, and infraorbital.

CONCLUSIONS

Understanding cranial landmarks and the folds of the layers covering the orbito-cavernous-pterygopalatine interface can facilitate tailoring an EEA to the medial orbital space and avoid unnecessary exposure of sensitive anatomy in the vicinity.

Contralateral Transmaxillary Approach for Resection of Chondrosarcoma of the Petrous Apex: A Case Report

BACKGROUND

Deep location and neurovascular structures make access to lesions of the petrous apex a significant challenge. A novel approach for these tumors is the contralateral transmaxillary approach.

CLINICAL PRESENTATION

A 31-year-old male was evaluated for left abducens nerve palsy. Magnetic resonance imaging (MRI) and computed tomography revealed an enhancing, lytic lesion of the petrous apex with extension to the cavernous sinus and petroclival junction. The patient underwent a combined endoscopic contralateral transmaxillary and endoscopic endonasal transclival approach for resection of the lesion. No new or worsening neurologic deficits were noted following the procedure. Pathology revealed low-grade chondrosarcoma (grade I). Postoperative MRI revealed gross total resection of the lesion. Patient underwent adjuvant radiation therapy at the discretion of radiation oncology.

CONCLUSION

The contralateral transmaxillary approach to the petrous apex allows for resection of lesions of the petrous apex with the ability to extend the dissection laterally. Excellent results achieved by institutions with advanced extended endoscopic endonasal experience can be reproduced in institutions with less experience. Further characterization of the risks and benefits of this approach is needed.

Endoscopic Endonasal versus Transcranial Optic Canal Decompression: A Morphometric, Cadaveric Study

Introduction Decompression of the optic nerve within the optic canal is indicated for compressive visual decline. The two most common approaches utilized for optic canal decompression are a medial approach with an endoscopic endonasal approach and a lateral approach with a craniotomy. Our study is a cadaveric anatomical study comparing the length and circumference of the orbit decompressed via an endoscopic endonasal approach versus a frontotemporal craniotomy.

Methods Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans were performed on each specimen. On each specimen, a standard frontotemporal craniotomy with anterior clinoidectomy and superolateral orbital decompression was performed on one side and an endoscopic endonasal approach with medial wall decompression was performed on the contralateral side. Post-dissection CT scans were performed. An independent radiologist provided measurements of the length (mm) and circumference (degrees) of optic canal decompression bilaterally.

Results The mean length of optic canal decompression for open and endoscopic approach was 13 mm (range 12–15 mm) and 12.4 mm (range 10–16 mm), respectively. The mean circumference of decompression for open and endoscopic approaches was 252.8 degrees (range 205–280 degrees) and 124.6 degrees (range 100–163 degrees), respectively.

Conclusion The endoscopic endonasal and the transcranial approaches provide a similar length of optic canal decompression, but the transcranial approach leads to greater circumferential decompression. The endoscopic endonasal approach has the benefit of being minimally invasive, though. Ultimately, the surgical approach decision should be based on the location of the pathology and the surgeon's comfort.

Comparative Analysis of Surgical Exposure among Endoscopic Endonasal Approaches to Petrosectomy: An Experimental Study in Cadavers

Objectives  Endoscopic endonasal approaches (EEAs) for petrosectomies are evolving to reduce perioperative brain injuries and complications. Surgical terminology, techniques, landmarks, advantages, and limitations of these approaches remain ill defined. We quantitatively analyzed the anatomical relationships and differences between EEA exposures for medial, inferior, and inferomedial petrosectomies. Design  This study presents anatomical dissection and quantitative analysis. Setting  Cadaveric heads were used for dissection. EEAs were performed using the medial petrosectomy (MP), the inferior petrosectomy (IP), and the inferomedial petrosectomy (IMP) techniques. Participants  Six cadaver heads (12 sides, total) were dissected; each technique was performed on four sides. Main Outcomes and Measures  Outcomes included the area of exposure, visible distances, angles of attack, and bone resection volume. Results  The IMP technique provided a greater area of exposure ( p  < 0.01) and bone resection volume ( p  < 0.01) when compared with the MP and IP techniques. The IMP technique had a longer working length of the abducens nerve (cranial nerve [CN] VI) than the MP technique ( p  < 0.01). The IMP technique demonstrated higher angles of attack to specific neurovascular structures when compared with the MP (midpons [ p  = 0.04], anterior inferior cerebellar artery [ p  < 0.01], proximal part of the cisternal CN VI segment [ p  = 0.02]) and IP (flocculus [ p  = 0.02] and the proximal [ p  = 0.02] and distal parts [ p  = 0.02] of the CN VII/VIII complex) techniques. Conclusion  Each of these approaches offers varying degrees of access to the petroclival region, and the surgical approach should be appropriately tailored to the pathology. Overall, the IMP technique provides greater EEA surgical exposure to vital neurovascular structures than the MP and the IP techniques.

Evaluation of Surgical Freedom for One-and-a-Half Nostril, Mononostril, and Binostril Endoscopic Endonasal Transsphenoidal Approaches

Objective  This article determines which of the one-and-a-half nostril, mononostril, and binostril endoscopic endonasal transsphenoidal approaches provide a superior manipulation during surgery. Methods  The three approaches were orderly performed on 10 silicon-injected cadaveric heads to quantitatively assess surgical freedom and attack angle for sella. Measurements were determined with a standardized method under neuronavigation system using data of computed tomography. Results  The one-and-a-half nostril endoscopic transsphenoidal approach (OETA) offered superior exposed area than that of the mononostril approach (META), and similar to that of the binostril approach (BETA). For surgical freedom at anatomic targets, the OETA showed greater surgical flexibility at pituitary center, the right medial optic carotid recess (R-mOCR), the left mOCR, the medial intersection of the right cavernous internal carotid artery, and extension line of upper margin of the clivus (R-mICC) than those of the META, and similar to those of the BETA. For sagittal angle of attack to the R-mOCR, R-mICC, and L-mOCR, the OETA can provide better angular freedom for surgeon than that of the META, and similar to that of the BETA. The OETA had the same axial attack to the pituitary center with the BETA. The OETA and the META had limited surgical freedom at L-mICC, and both inferior to the BETA. Conclusion  The OETA has similar exposed area, surgical freedom, and attack angle for most anatomic targets to the BETA without resecting contralateral nasal septal mucosa, and obviously superior to the META.

Endoscopic Endonasal Transsphenoidal Surgery: History and Evolution

In previous decades, extensive and disfiguring transfacial and/or transcranial approaches were used to reach the sellar and parasellar areas. However, these surgical routes were burdened by severe complications and high mortality rates. Recently, the development of endoscopic endonasal techniques has revolutionized the surgical strategies for approaching the sella and adjacent areas and increased the development of transsphenoidal surgery. With these techniques, surgeons have been able to overcome the visual limitations of the open surgical approaches and access areas previously hidden from view. After the contributions of the Pittsburgh duo, Carrau and Jho, pioneers of pure endoscopic surgery, our school began to implement this technique, introducing technical innovations and variations, describing the anatomical details and defining new routes, and playing a key role in its widespread clinical application.

Quantitative Comparison of Three Endoscopic Approaches to the Parasellar Region: Laboratory Investigation

BACKGROUND

Endoscopic endonasal transsphenoidal and contralateral sublabial transmaxillary approaches are used for approaching parasellar lesions. The aim of this anatomical study was to compare endoscopic endonasal uninostril and binostril (contralateral) and contralateral sublabial transmaxillary approaches via a quantitative analysis of exposure limits and instrument working avenues.

METHODS

Six formalin-fixed silicone-injected adult cadaveric heads (12 sides) were studied. The surgical working area, depth of the surgical corridor, angle of attack, and surgical freedom were measured and compared for the 3 approaches.

RESULTS

The endoscopic binostril endonasal approach to the parasellar area provided greater surgical freedom in the opticocarotid recess (OCR) and superior orbital fissure (SOF) compared with that of the uninostril endonasal approach (OCR, P < 0.01; SOF, P = 0.01) and the contralateral sublabial transmaxillary approach (OCR, P = 0.01; SOF, P = 0.03). The horizontal and vertical angles of attack with the binostril endonasal approach also were greater than those of the uninostril approach (OCR, P ≤ 0.05; SOF, P ≤ 0.01) and the contralateral transmaxillary approach (OCR, P ≤ 0.01; SOF, P ≤ 0.01). However, the contralateral sublabial transmaxillary approach provided more lateral exposure than the uninostril or binostril endonasal approach to the parasellar area, and it enabled a shorter surgical trajectory to the contralateral parasellar area (P < 0.01).

CONCLUSIONS

An anatomical comparison of the 3 endoscopic approaches to the parasellar area showed that the binostril approach provides greater exposure and freedom for instrument manipulation. The contralateral transmaxillary route provided a more lateral view, increasing exposure on average by 48%, with shorter surgical depth; however, surgical freedom was inferior to that of the binostril approach.

Endoscopic Medial Rectus Sling: A Window Into the Intraconal Orbital Apex

PURPOSE

Surgical approaches to the medial orbit especially within the cone of orbital muscles necessitate great precision and care to avoid damage to surrounding structures-most importantly the optic nerve. The authors present a novel technique in which access to the medial orbital contents was achieved through an entirely endoscopic approach.

METHODS

A 72-year-old Caucasian female presented with loss of vision in the right eye and reduced extraocular movements. Baseline blood tests were within normal limits. Inflammatory markers were slightly elevated. CT scan revealed bilateral medial orbital apex masses. Biopsy of the right orbital apex lesion was performed through an exclusively endoscopic approach in which the medial rectus muscle was retracted infero-medially.

RESULTS

This exclusively endonasal approach to the medial intraconal space provided excellent access to the orbital apex, thus allowing successful biopsy of the medial orbital apex lesion. A video of the surgical technique demonstrates its use in this patient (see Video, Supplemental Digital Content 1, available at http://links.lww.com/IOP/A123).

CONCLUSIONS

Similar reports of endonasal medialization of the medial rectus for accessing intraconal orbital lesions have been previously described in the rhinological literature. The authors describe a modification that allows for a safe and less invasive approach to the medial intraconal space and intraorbital optic nerve. There is minimal trauma to the surrounding tissues and no further damage to the optic nerve along with no associated adverse clinical sequelae. In addition, this negates the need for an adjuvant external or transconjunctival approach.

Modular Endoscopic Medial Maxillectomies: Quantitative Analysis of Surgical Exposure in a Preclinical Setting

BACKGROUND

The nomenclature adopted for endoscopic medial maxillectomies (EMMs) is exceedingly heterogeneous. The aim of this study was to objectively measure surgical exposure in a preclinical anatomic setting to validate a classification for modular EMMs.

MATERIALS AND METHODS

Computed tomography was used to scan 6 cadaver heads, and images were uploaded on dedicated software. A neuronavigation system was used to measure areas and volumes of surgical corridors during dissection. Differences of >10% of area exposed and >3 cm³ of volume were considered to define incremental types of EMM. Specific anatomic targets were assessed on the axial and sagittal planes. Influence of anatomic variants on surgical exposure was evaluated.

RESULTS

There were 4 types of EMMs (A-D), with a transseptal variant for each, identified. In the axial plane, type A exposed the vidian canal and foramen rotundum, type B exposed the foramen ovale and foramen spinosum, and transseptal type C or type D exposed the coronoid process. In the sagittal plane, type A exposed the vidian canal, and type B exposed the foramen ovale and styloid process. Transseptal type C exposed the pterygomaxillary fissure, and type D exposed the inferior border of the lateral pterygoid plate. The nasal floor limits the downward angle in transseptal approaches. The width of the piriform aperture independently influenced surgical volume of types B and C.

CONCLUSIONS

This modular classification of EMMs, based on quantitative analysis in a preclinical setting, should allow for better personalized preoperative surgical planning and provides standardization of nomenclature.

Transnasal endoscopic partial maxillectomy: Operative nuances and proposal for a comprehensive classification system based on 1378 cases

BACKGROUND

Despite the development of functional endoscopic endonasal surgery, there are still areas of the maxillary sinus that remain technically difficult to access using a standard middle meatal antrostomy as well as deep-seated skull base lesions requiring expanded transmaxillary approaches.

METHODS

All patients who underwent transnasal endoscopic partial maxillectomy (TEPM) in a single institution from 2000 to 2014 were retrospectively reviewed. The TEPM was classified into 5 types according to the anatomic structures progressively removed and to the access provided.

RESULTS

The TEPM was performed in 1378 patients for the management of: inflammatory diseases in 513 cases (37%), benign sinonasal tumors in 425 cases (31%), skull base malignancies in 285 cases (21%), and as a corridor to address deep-seated skull base lesions in 155 cases (11%).

CONCLUSION

The TEPM is a stepwise approach offering increasing access that can be tailored to different maxillary, sinonasal, and skull base pathologies with minimal morbidity for patients. © 2016 Wiley Periodicals, Inc. Head Neck 39: 754-766, 2017.

Interactive navigation-guided ophthalmic plastic surgery: assessment of optical versus electromagnetic modes and role of dynamic reference frame location using navigation-enabled human skulls

AIM

The aim of this study was to assess the anatomical accuracy of navigation technology in localizing defined anatomic landmarks within the orbit with respect to type of technology (optical versus electromagnetic systems) and position of the dynamic reference marker on the skull (vertex, temporal, parietal, and mastoid) using in vitro navigation-enabled human skulls. The role of this model as a possible learning tool for anatomicoradiological correlations was also assessed.

METHODS

Computed tomography (CT) scans were performed on three cadaveric human skulls using the standard image-guidance acquisition protocols. Thirty-five anatomical landmarks were identified for stereotactic navigation using the image-guided StealthStation S7™ in both electromagnetic and optical modes. Three outcome measures studied were accuracy of anatomical localization and its repeatability, comparisons between the electromagnetic and optical modes in assessing radiological accuracy, and the efficacy of dynamic reference frame (DRF) at different locations on the skull.

RESULTS

The geometric localization of all the identified anatomical landmarks could be achieved accurately. The Cohen's kappa agreements between the surgeons were found to be perfect (kappa =0.941) at all predetermined points. There was no difference in anatomical localization between the optical and electromagnetic modes (P≤0.001). Precision for radiological identification did not differ with various positions of the DRF. Skulls with intact anatomical details and careful CT image acquisitions were found to be stereotactically useful.

CONCLUSION

Accuracy of anatomic localization within the orbit with navigation technology is equal with optical and electromagnetic system. The location of DRF does not affect the accuracy. Navigation-enabled skull models can be potentially useful as teaching tools for achieving the accurate radiological orientation of orbital and periorbital structures.

The evolving role of the oculoplastic surgeon in skull base surgery

PURPOSE OF REVIEW

Classical orbital approaches in skull base surgery have involved large incisions with extensive bone removal resulting in prolonged recovery with associated morbidity and mortality. The purpose of this review is to explore recent advances in skull base surgery that are applicable to the orbital surgeon.

RECENT FINDINGS

Transnasal endoscopic surgery provides access to the medial 180 degrees of the orbit. Access to the lateral 180 degrees may be obtained using transmaxillary and transcranial techniques. Transorbital approaches and multiport techniques further expand the reach of the skull base surgeon. These minimally invasive techniques are supplanting the classical pterional, frontotemporal, frontotemporal orbitozygomatic, frontal, and subfrontal approaches.

SUMMARY

The role of the orbital surgeon in skull base surgery is changing. Transnasal and transcranial approaches to orbital disorders using minimally invasive techniques are becoming more common. In addition, transorbital access to the skull base, paranasal sinuses, and anterior and middle cranial fossa is offering new opportunities for the orbital surgeon.

Endoscopic Endonasal Management of Orbital Pathologies

Based on the anatomic relationship between sinonasal complex and orbit, endoscopic transnasal procedures could be a smart solution for approaching the medial orbital region. These techniques should be considered a valid option for optic nerve or orbital wall decompression in cases of Graves ophthalmopathy and post-traumatic optic neuropathy as well as for addressing extraconal or intraconal lesions placed medially to the optic nerve course. This article describes the anatomic principles, indications, technical nuances, and limitations of the endoscopic endonasal approaches for the management of selected orbital pathologic abnormalities.

Endoscopy-guided brachytherapy for sinonasal and nasopharyngeal recurrences

OBJECTIVE/PURPOSE

To evaluate the preliminary results of perioperative endoscopy-guided brachytherapy (BT) in recurrent sinonasal and nasopharyngeal tumors already treated for their primary tumor with a full course of radiotherapy.

METHODS AND MATERIALS

Patients with recurrence and already treated with a previous full course of radiotherapy >65 Gy who underwent BT from December 2010 to January 2014 were taken into account for this work. Macroscopic disease was resected by an endoscopic approach, and catheters for BT were endoscopically positioned and fixed at the same time on the surgical bed. Surgery was performed under electromagnetic navigation guidance. The irradiation dose was 30 Gy in 12 fractions, 2.5 Gy each, twice a day, in 6 days.

RESULTS

We performed the endoscopy-guided BT 11 times in 9 patients; in two cases, no previous radiation therapy had been performed; and in one case, followup was too short to be considered. A total of 6 patients were eligible for the analysis. One patient underwent BT three times because of previous target margin recurrences. There were no immediate complications. The median and mean followups were 21 and 19 months, respectively. The median V90 and V85% were 93% and 95%, respectively. In one case, we had a transient deficit of the VI cranial nerve (G3), and in another case, we diagnosed a noncomplicated osteonecrosis (G2). The median disease-free survival is 12 months, and the median overall survival is 23 months.

CONCLUSIONS

The combination of endoscopy and BT seems to be a safe option for treating recurrent sinonasal and nasopharyngeal tumors.