Single-Step Resection of Sphenoorbital Meningiomas and Orbital Reconstruction Using Customized CAD/CAM Implants

Spheno-Orbital Meningiomas: Advances in Reconstruction Workflow and Cosmetic/Functional Outcomes in the Digital Era

Spheno-orbital (SOM) meningioma is a rare subtype of skull base tumor characterized by the proliferation of arachnoid cap cells with intradural expansion, hyperostosis of calvarial and spheno-orbital bone, and consecutive infiltration of critical surrounding neurovascular structures of the frontotemporal base of the skull. Surgical resection is often challenging due to the infiltrative growth and the anatomically complex localization. In most cases, a microsurgical transcranial approach is performed, resulting in the need to reconstruct the orbit with or without a cranioplasty. This review highlights the evolution and current state-of-the-art reconstructive strategies used in SOM surgery.

Single-step 3D printing aided cranio-orbital reconstruction with patient specific polyetheretherketone implants after resection of benign spheno-orbital tumors

PURPOSE

Computer-aided design (CAD) and computer-aided manufacturing (CAM) techniques have paved the way for single-step resections and cranio-orbital reconstructions with patient specific implants in spheno-orbital tumors. Here, we present our interdisciplinary maxillofacial and neurosurgical workflow and a case series of patients treated with this integrated approach.

METHODS

Patients, who underwent single-step resection of benign spheno-orbital tumors and cranio-orbital reconstruction with polyetheretherketone (PEEK) patient specific implants (PSI) from 2019 to 2024 in our institution were included. Three dimensional models of the tumor, the skull, the implants and the cutting guides were integrated into intraoperative neuronavigation and 3D printed at the point of care (POC) for surgical planning. Clinical data was retrospectively analyzed, pre- and postoperative Exophthalmic index (EI) was radiologically determined.

RESULTS

Eleven patients met inclusion criteria. Meningioma WHO grade 1 was the most common tumor entity (81.8%). In a majority of patients, exophthalmos was the presenting sign (63.6%). Postoperative cranial imaging revealed an optimal position of the PEEK implants with regredient EI in 88.9%. Four (36.4%) patients, of whom two (50%) had undergone prior tumor resections, suffered from surgical complications. The most commonly recorded complication was impaired wound healing (n = 2). Tumor recurrence was observed in one (9.1%) patient at six months follow-up.

CONCLUSIONS

Single-step resection and reconstruction in spheno-orbital tumors with PEEK PSIs is feasible and combines surgical expertise, virtual implant design and 3D printing techniques. Favorable aesthetical, visual and oncological outcomes were achieved in this cohort, despite a significant risk for postoperative complications.

3D Printing for Customized Bone Reconstruction in Spheno-Orbital Meningiomas: A Systematic Literature Review and Institutional Experience

Background: The treatment of spheno-orbital meningiomas (SOMs) requires extensive bone resections, creating significant defects in a complex geometrical space. Bone reconstruction represents a fundamental step that optimizes long-term aesthetic and functional outcomes. In recent years, 3D printing technology has also been exploited for complex skull base reconstructions, but reports remain scarce. Methods: We retrospectively analyzed four consecutive patients who underwent SOM resection and one-step 3D PEEK customized reconstruction from 2019 to 2023. A systematic review of 3D printing customized implants for SOM was then performed. Results: All patients underwent a frontotemporal craniotomy, removal of SOM, and reconstruction of the superolateral orbital wall and pterional region. The aesthetic outcome was extremely satisfactory in all cases. No orbital implant malposition or infectious complications were documented. Eleven papers were included in the literature review, describing 27 patients. Most (23) patients underwent a single-stage reconstruction; in three cases, the implant was positioned to correct postoperative delayed enophthalmos. Porous titanium was the most used material (16 patients), while PEEK was used in three cases. Prosthesis malposition was described in two (7.4%) patients. Conclusions: Single-step reconstruction with a personalized 3D PEEK prosthesis represents a valid reconstruction technique for the treatment of SOMs with good aesthetic outcomes.

Patient-specific implants for reconstruction of orbit and skull following resection of spheno-orbital meningiomas: A two-implant concept

INTRODUCTION

The surgical treatment of spheno-orbital meningioma (SOM) is challenging. In addition to anatomical constraints that lead to a difficult resection, the reconstruction of the resulting defect is demanding. Uniform recommendations concerning the best reconstruction technique are not available in the existing literature. We propose a novel two-piece concept for reconstructing post-ablative defects using patient-specific implants.

MATERIAL AND METHODS

Between 2018 and 2021, seven patients underwent SOM resection using two digitally planned patient-specific implants for orbit and skull reconstruction. To analyze the accuracy of the reconstruction, preoperative plans were merged with postoperative data sets. The clinical outcome was evaluated by comparing the pre- and postoperative exophthalmos index (EI).

RESULTS

In all cases, adequate reconstruction and a satisfactory match between the final implant position and preoperative planning were achieved. The EI was reduced in all cases from a mean of 1.27 to 1.09 (p = 0.003).

CONCLUSIONS

The proposed concept of a two-piece reconstruction after SOM resection is an excellent way to manage the concern around post-ablative defects. The current technical conditions allow for a precise, safe, and predictable reconstruction.

Endoscopic Transorbital Approach for the Management of Spheno-Orbital Meningiomas: Literature Review and Preliminary Experience

OBJECTIVE

The endoscopic transorbital approach (ETOA) is a minimally invasive approach that could be particularly appropriate for management of spheno-orbital meningiomas. The aim of this study was to perform a systematic review of the literature on the management of spheno-orbital meningiomas via the minimally invasive ETOA, searching for clinical scenarios in which this approach could be best indicated. A secondary aim was to describe 4 illustrative cases.

METHODS

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Data including patient demographics, tumor features, and surgical and postoperative outcomes were collected. Cases from our initial experience with ETOA were included in the data.

RESULTS

Data of 58 patients from 9 selected records and from our surgical series were collected. Subtotal, near-total, and gross total resection rates were 44.8%, 10.3%, and 32.7%, respectively. Symptom improvement after surgery was 100% for proptosis, 93% for visual impairment, and 87% for ophthalmoplegia. The most common postoperative complications were transient ophthalmoplegia and maxillary nerve hypoesthesia. Cerebrospinal fluid leak was reported in 2 patients.

CONCLUSIONS

Our findings support the use of the ETOA for management of spheno-orbital meningiomas, particularly in at least 3 clinical scenarios: 1) when predominant hyperostotic bone is present; 2) when a globular tumor not showing excessive medial or inferior infiltration is being treated; 3) as part of a multistage treatment for diffuse lesions.

Radiomics and machine learning for predicting the consistency of benign tumors of the central nervous system: A systematic review

PURPOSE

Predicting the consistency of benign central nervous system (CNS) tumors prior to surgery helps to improve surgical outcomes. This review summarizes and analyzes the literature on using radiomics and/or machine learning (ML) for consistency prediction.

METHOD

The Medical Literature Analysis and Retrieval System Online (MEDLINE) database was screened for studies published in English from January 1st 2000. Data was extracted according to the PRISMA guidelines and quality of the studies was assessed in compliance with the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

RESULTS

Eight publications were included focusing on pituitary macroadenomas (n = 5), pituitary adenomas (n = 1), and meningiomas (n = 2) using a retrospective (n = 6), prospective (n = 1), and unknown (n = 1) study design with a total of 763 patients for the consistency prediction. The studies reported an area under the curve (AUC) of 0.71-0.99 for their respective best performing model regarding the consistency prediction. Of all studies, four articles validated their models internally whereas none validated their models externally. Two articles stated making data available on request with the remaining publications lacking information with regard to data availability.

CONCLUSIONS

The research on consistency prediction of CNS tumors is still at an early stage regarding the use of radiomics and different ML techniques. Best-practice procedures regarding radiomics and ML need to be followed more rigorously to facilitate the comparison between publications and, accordingly, the possible implementation into clinical practice in the future.

Extensive extracranial growth of spheno-orbital meningioma: illustrative case

BACKGROUND

Spheno-orbital meningioma (SOM) typically presents with a classic triad of symptoms (i.e., proptosis, visual impairment, and ocular paresis), resulting from intraorbital tumor invasion. The authors present a very rare case of SOM in which the chief complaint was swelling of the left temporal region, which, to the best of their knowledge, has not been reported previously.

OBSERVATIONS

The patient presented with marked extracranial extension to the left temporal region but unremarkable intraorbital extension, even on radiological examination. Physical examination of the patient showed almost no exophthalmos or restriction of left eye movement, consistent with the radiological findings. Four separate meningioma specimens were removed by extraction (i.e., one each from the intracranial, extracranial, and intraorbital segments of the tumor and one from the skull). The World Health Organization grade was 1 and the MIB-1 index was less than 1%, indicating a diagnosis of a benign tumor.

LESSONS

SOM may be present even in patients with only temporal swelling and few ocular-related symptoms, and detailed imaging evaluations may be required to identify the tumor.

Machine Learning for the Detection and Segmentation of Benign Tumors of the Central Nervous System: A Systematic Review

Simple Summary

Machine learning in radiology of the central nervous system has seen many interesting publications in the past few years. Since the focus has largely been on malignant tumors such as brain metastases and high-grade gliomas, we conducted a systematic review on benign tumors to summarize what has been published and where there might be gaps in the research. We found several studies that report good results, but the descriptions of methodologies could be improved to enable better comparisons and assessment of biases.

Abstract

Objectives: To summarize the available literature on using machine learning (ML) for the detection and segmentation of benign tumors of the central nervous system (CNS) and to assess the adherence of published ML/diagnostic accuracy studies to best practice. Methods: The MEDLINE database was searched for the use of ML in patients with any benign tumor of the CNS, and the records were screened according to PRISMA guidelines. Results: Eleven retrospective studies focusing on meningioma (n = 4), vestibular schwannoma (n = 4), pituitary adenoma (n = 2) and spinal schwannoma (n = 1) were included. The majority of studies attempted segmentation. Links to repositories containing code were provided in two manuscripts, and no manuscripts shared imaging data. Only one study used an external test set, which raises the question as to whether some of the good performances that have been reported were caused by overfitting and may not generalize to data from other institutions. Conclusions: Using ML for detecting and segmenting benign brain tumors is still in its infancy. Stronger adherence to ML best practices could facilitate easier comparisons between studies and contribute to the development of models that are more likely to one day be used in clinical practice.

Quantitative Anatomic Comparison of Microsurgical Transcranial, Endoscopic Endonasal, and Transorbital Approaches to the Spheno-Orbital Region

BACKGROUND

The spheno-orbital region (SOR) is a complex anatomic area that can be accessed with different surgical approaches.

OBJECTIVE

To quantitatively compare, in a preclinical setting, microsurgical transcranial approaches (MTAs), endoscopic endonasal transpterygoid approach (EEA), and endoscopic transorbital approaches (ETOAs) to the SOR.

METHODS

These approaches were performed in 5 specimens: EEA, ETOAs (superior eyelid and inferolateral), anterolateral MTAs (supraorbital, minipterional, pterional, pterional-transzygomatic, and frontotemporal-orbitozygomatic), and lateral MTAs (subtemporal and subtemporal transzygomatic). All specimens underwent high-resolution computed tomography; an optic neuronavigation system with dedicated software was used to quantify working volume and exposed area for each approach. Mixed linear models with random intercepts were used for statistical analyses.

RESULTS

Anterolateral MTAs offer a direct route to the greater wings (GWs) and lesser wings (LWs); only they guarantee exposure of the anterior clinoid. Lateral MTAs provide access to a large area corresponding to the GW, up to the superior orbital fissure (SOF) anteriorly and the foramen rotundum medially. ETOAs also access the GW, close to the lateral portion of SOF, but with a different angle of view as compared to lateral MTAs. Access to deep and medial structures, such as the lamina papyracea and the medial SOF, is offered only by EEA, which exposes the LW and GW only to a limited extent.

CONCLUSION

This is the first study that offers a quantitative comparison of the most used approaches to SOR. A detailed knowledge of their advantages and limitations is paramount to choose the ideal one, or their combination, in the clinical setting.

Inferolateral Transorbital Endoscopic Approach for Spheno-Orbital Meningiomas

ABSTRACT

Spheno-orbital meningiomas (SOM) are slow growing tumors that often cause proptosis and visual deficits, due to direct compression of adjacent structures or hyperostosis of surrounding bones.Traditionally, these lesions are approached via a lateral transcranial route. Recent interest in mini-invasive surgery and endoscopy brought many authors to study different trans-nasal or trans-orbital approaches.The authors report a surgical case series with 3 patients with proptosis due to SOM who underwent surgery in our institution via an inferolateral trans-orbital endoscopic approach. The authors described our surgical technique and the authorsretrospectively reviewed the clinical and radiological outcomes of the patients.All 3 patients had an effective orbital decompression with improvement of the proptosis and pain relief. Histological examination was possible and no intraoperative nor postoperative complications were observed.Therefore, the authors consider inferolateral trans-orbital endoscopic approach as a feasible approach for lesions involving the lateral orbit compartment arising from middle cranial fossa or from orbit itself.