Cranio-Orbital and Orbitocranial Approaches to Orbital and Intracranial Disease: Eye-Opening Approaches for Neurosurgeons

Frontotemporal Approach for Spheno-Orbital Meningioma and Orbital Compartment Resection: Technical Case Instruction: 2-Dimensional Operative Video

BACKGROUND AND IMPORTANCE

Spheno-orbital meningiomas (SOMs) pose a challenge to the skull base neurosurgeon because of their variable presentation and involvement of critical structures within the orbit. There is no consensus on optimal management of these patients and how to achieve maximal safe resection. The authors share an illustrative case with an accompanying video to demonstrate their aggressive approach to resect SOMs and their intraorbital components.

CLINICAL PRESENTATION

A 75-year-old-woman presented with progressive vision loss and proptosis. Magnetic resonance imaging was consistent with a large, left-sided sphenoid wing meningioma with extension to the orbital wall and compression of the optic nerve medially. The patient elected to undergo surgical excision and optic nerve decompression. She did well postoperatively with resolution of proptosis and good resection margins on follow-up imaging.

CONCLUSION

Aggressive resection of SOMs is possible with an understanding of the underlying anatomy. Familiarity with the orbit can facilitate a maximal safe resection with optic nerve decompression.

Navigating the Intersection Between the Orbit and the Skull Base: The "Mirror" McCarty Keyhole During Transorbital Approach: An Anatomic Study With Surgical Implications

BACKGROUND AND OBJECTIVES

McCarty keyhole (MCK) is the most important entry point during orbitocranial and cranio-orbital approaches; nevertheless, its anatomic coordinates have never been detailedly described from transorbital perspective. To provide the spatial coordinates for intraorbital projection of the "mirror" MCK by using the well-established main anatomic-surgical bony landmarks met along transorbital corridor.

METHODS

MCK was identified in 15 adult dry skulls (30 sides) on exocranial surface of pterional region based on the well-defined external bony landmarks: on the frontosphenoid suture, 5 to 6 mm behind the joining point (JP) of frontozygomatic suture (FZS), frontosphenoid suture (FSS), and sphenozygomatic suture (SZS). A 1-mm burr hole was performed and progressively enlarged to identify the intracranial and intraorbital compartments. Exit site of the intraorbital part of burr hole was referenced to the FZS on the orbital rim, the superior orbital fissure, and the inferior orbital fissure and to the JP of FZS, FSS, and SZS. To electronically validate the results, 3-dimensional photorealistic and interactive models were reconstructed with photogrammetry. Finally, for a further validation, McCarty mirror keyhole was also exposed, based on results achieved, through endoscopic transorbital approach in 10 head specimens (20 sides).

RESULTS

Intraorbital projection of MCK was identified on the FSS on intraorbital surface, 1.5 ± 0.5 mm posterior to JP, 11.5 ± 1.1 mm posterior to the FZS on orbital rim following the suture, 13.0 ± 1.2 mm from most anterior end of superior orbital fissure, 15.5 ± 1.4 mm from the most anterior end of the inferior orbital fissure in vertical line, on measurements under direct macroscopic visualization (mean ± SD). These values were electronically confirmed on the photogrammetric models with mean difference within 1 mm.

CONCLUSION

To be aware of exact position of intraorbital projection of MCK during an early stage of transorbital approaches provides several surgical, clinical, and aesthetic advantages.

Spheno-Orbital Meningiomas: The Rationale behind the Decision-Making Process of Treatment Strategy

Surgery stands as the primary treatment for spheno-orbital meningiomas, following a symptoms-oriented approach. We discussed the decision-making process behind surgical strategies through a review of medical records from 80 patients who underwent surgical resection at the University of Naples Federico II. Different surgical approaches were employed based on the tumor's location relative to the optic nerve's long axis, categorized into lateral (type I), medial (type II), and diffuse (type III). We examined clinical, neuroradiological, surgical, pathological, and outcome factors. Proptosis emerged as the most frequent symptom (97%), followed by visual impairment (59%) and ocular motility issues (35%). Type I represented 20%, type II 43%, and type III 17%. Growth primarily affected the optic canal (74%), superior orbital fissure (65%), anterior clinoid (60%), and orbital apex (59%). The resection outcomes varied, with Simpson grades I and II achieved in all type I cases, 67.5% of type II, and 18% of type III. Recurrence rates were highest in type II (41.8%) and type III (59%). Improvement was notable in proptosis (68%) and visual function (51%, predominantly type I). Surgery for spheno-orbital meningiomas should be tailored to each patient, considering individual characteristics and tumor features to improve quality of life by addressing primary symptoms like proptosis and visual deficits.

Fully Endoscopic Minimally Invasive Trans-Eyebrow Supraorbital Translaminar Approach to Third Ventricle Craniopharyngiomas: Technical Nuances and Stepwise Illustrative Description

BACKGROUND

Traditional microsurgical approaches for addressing intraventricular craniopharyngioma provide limited access to the retrochiasmatic area and tumors with significant lateral or rostrocaudal extensions. Extended endoscopic endonasal approaches can effectively overcome many of limitations, yet they require a favorable working angle between the optic chiasm and pituitary gland, as well as the involvement of the third ventricle floor by the tumor.

METHODS

Herein, the authors describe the surgical nuances of a keyhole technique for resecting third ventricle craniopharyngiomas via a fully endoscopic minimally invasive trans-eyebrow supraorbital translaminar approach (ESOTLA). A case description detailing the key surgical steps and application of the approach is provided, along with a series of cadaveric photographs to highlight the relevant anatomy and step-by-step dissection process.

RESULTS

The patient is a 44-year-old man who presented with polyuria, low urine specific gravity, and panhypopituitarism. Brain magnetic resonance imaging revealed a solid-cystic heterogeneous-enhanced retrochiasmatic mass within the third ventricle, consistent with craniopharyngioma. A 1-stage ESOTLA was indicated based on the narrow pituitary-chiasm angle and the high functional status of the patient. Near-total resection was achieved, and no new postoperative neurologic or endocrine change was observed. Targeted therapy was implemented based on the histologic result, and the most recent surveillance magnetic resonance imaging showed no evidence of the residual tumor.

CONCLUSIONS

By combining a keyhole approach with variable-angle endoscopic visualization through a smaller bony and soft tissue exposure, ESOTLA can provide enhanced illumination within the third ventricle, potentially addressing cosmetic concerns and limited exposure area/angle of freedom associated with its conventional microsurgical counterpart.

Preservation of cranial nerve function in large and giant trigeminal schwannoma resection: a case series

BACKGROUND

Trigeminal schwannomas (TSs) are intracranial tumors that can cause significant brainstem compression. TS resection can be challenging because of the risk of new neurologic and cranial nerve deficits, especially with large (≥ 3 cm) or giant (≥ 4 cm) TSs. As prior surgical series include TSs of all sizes, we herein present our clinical experience treating large and giant TSs via microsurgical resection.

METHODS

This was a retrospective, single-surgeon case series of adult patients with large or giant TSs treated with microsurgery in 2012-2023.

RESULTS

Seven patients underwent microsurgical resection for TSs (1 large, 6 giant; 4 males; mean age 39 ± 14 years). Tumors were classified as type M (middle fossa in the interdural space; 1 case, 14%), type ME (middle fossa with extracranial extension; 3 cases, 43%), type MP (middle and posterior fossae; 2 cases, 29%), or type MPE (middle/posterior fossae and extracranial space; 1 case, 14%). Six patients were treated with a frontotemporal approach (combined with transmastoid craniotomy in the same sitting in one patient and a delayed transmaxillary approach in another), and one patient was treated using an orbitofrontotemporal approach. Gross total resection was achieved in 5 cases (2 near-total resections). Five patients had preoperative facial numbness, and 6 had immediate postoperative facial numbness, including two with worsened or new symptoms. Two patients (28%) demonstrated new non-trigeminal cranial nerve deficits over mean follow-up of 22 months. Overall, 80% of patients with preoperative facial numbness and 83% with facial numbness at any point experienced improvement or resolution during their postoperative course. All patients with preoperative or new postoperative non-trigeminal tumor-related cranial nerve deficits (4/4) experienced improvement or resolution on follow-up. One patient experienced tumor recurrence that has been managed conservatively.

CONCLUSIONS

Microsurgical resection of large or giant TSs can be performed with low morbidity and excellent long-term cranial nerve function.

360 Degrees Endoscopic Access to and Through the Orbit

The treatment of pathologies located within and surrounding the orbit poses considerable surgical challenges, due to the intricate presence of critical neurovascular structures in such deep, confined spaces. Historically, transcranial and craniofacial approaches have been widely employed to deal with orbital pathologies. However, recent decades have witnessed the emergence of minimally invasive techniques aimed at reducing morbidity. Among these techniques are the endoscopic endonasal approach and the subsequently developed endoscopic transorbital approach (ETOA), encompassing both endonasal and transpalpebral approaches. These innovative methods not only facilitate the management of intraorbital lesions but also offer access to deep-seated lesions within the anterior, middle, and posterior cranial fossa via specific transorbital and endonasal corridors. Contemporary research indicates that ETOAs have demonstrated exceptional outcomes in terms of morbidity rates, cosmetic results, and complication rates. This study aims to provide a comprehensive description of endoscopic-assisted techniques that enable a 360° access to the orbit and its surrounding regions. The investigation will delve into indications, advantages, and limitations associated with different approaches, while also drawing comparisons between endoscopic approaches and traditional microsurgical transcranial approaches.

Site-based customized surgical approaches for orbital lesion and their outcomes - A case series

INTRODUCTION AND IMPORTANCE

The orbit is a complex region of the body that is susceptible to several diseases. The term "anterior orbitotomy" describes access to the orbit through the conjunctiva or eyelid from the front. This includes transconjunctival, medial, inferior, and superior approaches. The superior and lateral regions of the posterior orbit can be adequately exposed using a frontotemporal orbitozygomatic approach. The main aim of orbital surgery is to preserve vision. We discuss numerous surgical procedures for ocular tumours in this case series, along with the results of those procedures.

CASE PRESENTATION

In this case series, various surgical procedures for ocular tumours are discussed, along with their results postoperatively. Meningioma, cavernous hemangioma, dermoid, and Erdheim Chester disease were among the diagnoses. The early surgical outcome parameters in this case series were increased ocular motility and decreased proptosis.

CLINICAL DISCUSSION

A medial orbitotomy was done as the lesion was in the medial orbit in our first case. In the second, third, and fourth cases, lateral orbitotomies were done because the lesion was in the lateral orbit. The frontotemporal orbitozygomatic approach was used in the fifth and sixth cases with the lesion reaching the orbital apex. Patients with symptoms should consider surgical excision, which involves completely removing the tumour while maintaining the functionality of the muscles and optic nerve. Having a good surgical view and exposure is essential to understand the anatomical relationships in a small area.

CONCLUSION

The surgical strategy should be used in a manner that maintains visual acuity, limits injury to nearby objects, lowers postoperative morbidity, and is cosmetically acceptable.

Through the orbit and beyond: Current state and future perspectives in endoscopic orbital surgery on behalf of the EANS frontiers committee in orbital tumors and the EANS skull base section

Introduction

Orbital surgery has always been disputed among specialists, mainly neurosurgeons, otorhinolaryngologists, maxillofacial surgeons and ophthalmologists. The orbit is a borderland between intra- and extracranial compartments; Krönlein's lateral orbitotomy and the orbitozygomatic infratemporal approach are the historical milestones of modern orbital-cranial surgery.

Research question

Since its first implementation, endoscopy has significantly impacted neurosurgery, changing perspectives and approaches to the skull base. Since its first application in 2009, transorbital endoscopic surgery opened the way for new surgical scenario, previously feasible only with extensive tissue dissection.

Material and methods

A PRISMA based literature search was performed to select the most relevant papers on the topic.

Results

Here, we provide a narrative review on the current state and future trends in endoscopic orbital surgery.

Discussion and conclusion

This manuscript is a joint effort of the EANS frontiers committee in orbital tumors and the EANS skull base section.

Indications and outcomes of endoscopic transorbital surgery for trigeminal schwannoma based on tumor classification: a multicenter study with 50 cases

OBJECTIVE

Trigeminal schwannoma is a rare CNS tumor and involves the multicompartmental skull base. Recently, the endoscopic transorbital approach (ETOA) has emerged as a technique for minimally invasive surgery. The objective of this study was to evaluate the optimal indications and clinical outcomes of the ETOA for trigeminal schwannomas based on their tumor classification.

METHODS

Between September 2016 and February 2022, the ETOA was performed in 50 patients with trigeminal schwannoma at four tertiary hospitals. There were 15 men and 35 women in the study, with a mean age of 46.9 years. All tumors were classified as type A (predominantly involving the middle cranial fossa), type B (predominantly involving the posterior cranial fossa), type C (dumbbell-shaped tumors involving the middle and posterior fossa), or type D (involvement of the extracranial compartment). Type D tumors were also subclassified by ophthalmic division (D1), maxillary division (D2), and mandibular division (D3). Clinical outcome was analyzed, including extent of resection and surgical morbidities.

RESULTS

In this study, overall gross-total resection (GTR) was performed in 35 (70.0%) of 50 patients and near-total resection (NTR) in 9 patients (18.0%). The mean follow-up period was 21.9 (range 1-61.7) months. There was no tumor regrowth or recurrence during the follow-up period. Based on the classification, there were 17 type A tumors, 20 type C, and 13 type D. There were no type B tumors. Of the 13 type D tumors, 7 were D1, 1 D2, and 5 D3. For type A tumors, GTR or NTR was achieved using an ETOA in 16 (94.1%) of 17 patients. Eighteen (90.0%) of 20 patients with type C tumors attained GTR or NTR. Ten (76.9%) of 13 patients with type D tumors underwent GTR. Statistical analysis showed that there was no significant difference in the extent of resection among the tumor subtypes. Surgical complications included transient partial ptosis (n = 4), permanent ptosis (n = 1), transient diplopia (n = 7), permanent diplopia (n = 1), corneal keratopathy (n = 7), difficulties in mastication (n = 5), and neuralgic pain or paresthesia (n = 14). There were no postoperative CSF leaks or enophthalmos during follow-up.

CONCLUSIONS

This study showed that trigeminal schwannomas can be effectively treated with a minimally invasive ETOA in all tumor types, except those predominantly involving the posterior fossa (type B). For the extracranial compartments, D2 or D3 tumor types often require an ETOA combined with the endoscopic endonasal approach, while D1 tumor types can be treated using an ETOA alone.

The Transcaruncular Corridor of the Medial Transorbital Approach to the Frontal Lobe: Technical Nuances and Applications

BACKGROUND AND IMPORTANCE

Medial orbital access through a transcaruncular corridor has yet to be fully characterized as a potential approach to intradural lesions within the skull base. Transorbital approaches present unique potential in the management of complex neurological pathologies and require subspecialty collaboration across multiple disciplines.

CLINICAL PRESENTATION

A 62-year-old man presented with progressive confusion and mild left-sided weakness. He was found to have a right frontal lobe mass with significant vasogenic edema. A comprehensive systemic workup was otherwise unremarkable. A multidisciplinary skull base tumor board conference recommended a medial transorbital approach through transcaruncular corridor, which was performed by neurosurgery and oculoplastics services. Postoperative imaging demonstrated gross total resection of the right frontal lobe mass. Histopathologic evaluation was consistent with amelanotic melanoma with BRAF (V600E) mutation. At his last follow-up visit, 3 months after surgery, the patient did not experience any visual symptoms and had an excellent cosmetic outcome after surgery.

CONCLUSION

The transcaruncular corridor through a medial transorbital approach provides a safe and reliable access to the anterior cranial fossa.

History, Current Techniques, and Future Prospects of Surgery to the Sellar and Parasellar Region

The sellar and parasellar region can be affected by diverse pathologies. The deep-seated location and surrounding critical neurovascular structures make treatment challenging; there is no singular, optimal approach for management. The history and development of transcranial and transsphenoidal approaches by pioneers in skull base surgery were largely aimed at treating pituitary adenomas, which are the most common lesions of the sella. This review explores the history of sellar surgery, the most commonly used approaches today, and future considerations for surgery of the sellar/parasellar region.

Demineralized cortical fibers are associated with a low pseudarthrosis rate in patients undergoing surgery for adult spinal deformity without three-column osteotomy

Introduction

Following surgical treatment for adult spinal deformity (ASD) there is an increased risk of revision surgery due to mechanical failure or pseudarthrosis. Demineralized cortical fibers (DCF) were introduced at our institution aiming to reduce the risk of pseudarthrosis after ASD surgery.

Research question

We wanted to investigate the effect of DCF on postoperative pseudarthrosis compared with allogenic bone graft in ASD surgery without three-column osteotomies (3CO).

Materials & Methods

All patients undergoing ASD surgery between January 1, 2010 to June 31, 2020 were included in this interventional study with historical controls. Patients with current or previous 3CO were excluded. Before February 1, 2017, patients undergoing surgery received auto- and allogenic bone graft (non-DCF group) whilst patients after received DCF in addition to autologous bone graft (DCF group). Patients were followed for at least two years. The primary outcome was radiographic or CT-verified postoperative pseudarthrosis requiring revision surgery.

Results

We included 50 patients in the DCF group and 85 patients in the non-DCF group for final analysis. Pseudarthrosis requiring revision surgery at two-year follow-up occurred in seven (14%) patients in the DCF group compared with 28 (33%) patients in the non-DCF group (p ​= ​0.016). The difference was statistically significant, corresponding to a relative risk of 0.43 (95%CI: 0.21-0.94) in favor of the DCF group.

Conclusion

We assessed the use of DCF in patients undergoing ASD surgery without 3CO. Our results suggest that the use of DCF was associated with a considerable decreased risk of postoperative pseudarthrosis requiring revision surgery.

Transorbital drillout to the cavernous sinus: an approach for squamous cell carcinoma with perineural spread. Illustrative cases

BACKGROUND

This study describes a transorbital apical approach to the cavernous sinus, where the greater wing of sphenoid (GWS) and superior orbital fissure (SOF) are drilled out to access the interdural incision zone and lateral wall of the cavernous sinus.

OBSERVATIONS

This was a retrospective series of 3 patients with periocular squamous cell carcinoma (SCC) and radiological evidence of perineural spread to the cavernous sinus. Following an orbital exenteration, the GWS was drilled to reach the lateral border of the SOF. The meningo-orbital band, a periosteal transition between the frontotemporal basal dura and periorbita, was incised to enter the lateral wall of the cavernous sinus. The relevant cranial nerves were biopsied to provide an accurate zonal classification of disease.

LESSONS

The transorbital apical approach via the SOF provides a corridor of access to the cranial nerves within the lateral wall of the cavernous sinus. This technique was successfully performed on 3 patients with periocular SCC. One case had radiological evidence of intracavernous oculomotor nerve involvement, 1 patient demonstrated nasociliary nerve enlargement at the SOF, and another had frontal nerve involvement extending into the cavernous sinus. Cerebrospinal fluid leak occurred in 1 case addressed with fat packing and fascial closure.

Modified Lateral Orbitotomy Approach to Lesions of the Orbital Apex, Superior Orbital Fissure, Cavernous Sinus, and Middle Cranial Fossa

BACKGROUND

The lateral orbitotomy approach (LOA) provides minimally invasive access to the orbit, cavernous sinus region, and middle cranial fossa. Orbital retraction with this approach can nonetheless injure orbital structures, causing unnecessary morbidity.

OBJECTIVE

To describe our clinical experience with the modified LOA (mLOA), wherein the medial aspect of the lateral orbital wall posterior to the orbital rim is preserved.

METHODS

This is a retrospective, single-institution case series of patients undergoing a mLOA for lesions of the orbital apex, superior orbital fissure, cavernous sinus, and middle cranial fossa. The dimensions and variance of selected anatomic parameters relevant to this approach (orbital rim-superior orbital fossa depth, lateral orbital wall angle) were also analyzed using computed tomography scans from 30 adult patients.

RESULTS

Eight patients underwent a mLOA (mean age 54.0 ± 19.6 years; 3 males). Surgical targets included the superior orbital fissure (2; cavernoma and meningioma), sphenoid wing with or without the orbital apex (2; meningioma), cavernous sinus (2; rule out carcinoma and smooth muscle tumor), and anterior/mesial temporal lobe (2; cavernoma). Visual acuity/fields and diplopia was stable or improved in all patients postoperatively. One patient experienced a cerebrospinal fluid leak. On computed tomography analysis, the relevant bony anatomy displayed limited variability, with a mean orbital fossa depth of 42.7 ± 2.8 mm and a lateral orbital wall angle of 44.4° ± 2.7°.

CONCLUSION

The mLOA can provide safe, minimally invasive access to select lesions of the orbital apex, superior orbital fissure, cavernous sinus, and middle cranial fossa. The operative corridor has relatively consistent bony anatomy.

Functional and clinical outcomes after superior eyelid transorbital endoscopic approach for spheno-orbital meningiomas: illustrative case and literature review

The pattern of growth of spheno-orbital meningiomas accounts for the main presenting symptoms, such as proptosis, eye motility deficit, visual impairment, diplopia. As these are benign tumors, the postoperative patient's quality of life is an important factor to consider during the preoperative planning. A detailed literature review of superior eyelid transorbital endoscopic approach for spheno-orbital meningiomas, including our own case, was made. A Medline search up to March 2022 in PubMed online electronic database was made using the following key phrases: "superior eyelid endoscopic transorbital approach spheno-orbital meningiomas," "superior eyelid endoscopic transorbital approach," "spheno-orbital meningiomas endoscopic approach." The inclusion criteria were surgical series, reviews, and case reports in English language, as well as papers written in other languages, but including the abstract in English. Cadaveric studies, multiportal combined approaches for SOM, were excluded. The literature review has disclosed five studies for a total of 65 patients, whose demographic, clinical, pathological, surgical, complications, and outcome data were analyzed. Functional and esthetic outcome data after superior eyelid transorbital approach are the following: improvement of proptosis (100%), of visual deficits (66.66%) and of ocular paresis (75%), with only 11 complications (4 trigeminal dysesthesia, 2 CSF leak, 2 wound complications, 1 upper eyelid necrosis, 1 hemorrhage of surgical field, 1 keratitis) reported, but at the expense of extent of resection (gross total resection 33.39%). Based on the outcome data, the superior eyelid transorbital endoscopic approach results in a suitable operative technique for selected spheno-orbital meningiomas.

Alternative Path for Optic Nerve Decompression in Pseudotumor Cerebri With Full Endoscopic Lateral Transorbital Approach

Endonasal endoscopic approaches are the most preferred surgical methods in patients with pseudotumor cerebri because of easy access to the optic nerve, but the choice of this technique may not apply to all endoscopic endonasal cases. Moreover, there may be difficulties in practice in some cases, including the coronavirus disease 2019 pandemic. This study aimed to suggest an alternative endoscopic approach by lateral orbitotomy for optic nerve decompression in patients with pseudotumor cerebri. The study was performed using 5 fresh-frozen cadaver heads (bilaterally, total of 10 sides) injected intravenously with colored silicone preserved in the cold chain. An average of 2.5 cm skin incision was made to fit the lateral orbitotomy. The lengths of the recurrent meningeal artery (mm), the meningo-orbital band (mm), and the optic nerve (mm) to the orbital margin were measured. After these morphometric measurements, optic nerve decompression was performed endoscopically, and the length of the decompression was measured (mm). The average length (mm) between the orbital rim and meningeal recurrent artery (or meningolacrimal branch) was 16.2 mm, between the orbital rim and the meningo-orbital band was 18.5 mm, and between the orbital rim and optic nerve was 44.1 mm. The average optic nerve decompression length was 4.4 mm. The endoscopic lateral orbitotomy approach provides easy access to the optic nerve by anatomically following the recurrent meningeal artery and the meningo-orbital band. It can be a safe second-line approach after endonasal approaches for optic nerve decompression in pseudotumor cerebri.

The Ethical Implications of Tissue Engineering for Regenerative Purposes: A Systematic Review

Tissue Engineering (TE) is a branch of Regenerative Medicine (RM) that combines stem cells and biomaterial scaffolds to create living tissue constructs to restore patients' organs after injury or disease. Over the last decade, emerging technologies such as 3D bioprinting, biofabrication, supramolecular materials, induced pluripotent stem cells, and organoids have entered the field. While this rapidly evolving field is expected to have great therapeutic potential, its development from bench to bedside presents several ethical and societal challenges. To make sure TE will reach its ultimate goal of improving patient welfare, these challenges should be mapped out and evaluated. Therefore, we performed a systematic review of the ethical implications of the development and application of TE for regenerative purposes, as mentioned in the academic literature. A search query in PubMed, Embase, Scopus, and PhilPapers yielded 2451 unique articles. After systematic screening, 237 relevant ethical and biomedical articles published between 2008 and 2021 were included in our review. We identified a broad range of ethical implications that could be categorized under 10 themes. Seven themes trace the development from bench to bedside: (1) animal experimentation, (2) handling human tissue, (3) informed consent, (4) therapeutic potential, (5) risk and safety, (6) clinical translation, and (7) societal impact. Three themes represent ethical safeguards relevant to all developmental phases: (8) scientific integrity, (9) regulation, and (10) patient and public involvement. This review reveals that since 2008 a significant body of literature has emerged on how to design clinical trials for TE in a responsible manner. However, several topics remain in need of more attention. These include the acceptability of alternative translational pathways outside clinical trials, soft impacts on society and questions of ownership over engineered tissues. Overall, this overview of the ethical and societal implications of the field will help promote responsible development of new interventions in TE and RM. It can also serve as a valuable resource and educational tool for scientists, engineers, and clinicians in the field by providing an overview of the ethical considerations relevant to their work. Impact statement To our knowledge, this is the first time that the ethical implications of Tissue Engineering (TE) have been reviewed systematically. By gathering existing scholarly work and identifying knowledge gaps, this review facilitates further research into the ethical and societal implications of TE and Regenerative Medicine (RM) and other emerging biomedical technologies. Moreover, it will serve as a valuable resource and educational tool for scientists, engineers, and clinicians in the field by providing an overview of the ethical considerations relevant to their work. As such, our review may promote successful and responsible development of new strategies in TE and RM.

Management of Skull-Base Meningiomas With Extracranial Extensions: Clinical Features, Radiological Findings, Surgical Strategies, and Long-Term Outcomes

Objectives:

The aim of this research was to summarize the clinical and prognostic features of the skull-base meningiomas with extracranial extensions, and enhance the management of skull-base communicative meningiomas.

Methods

We retrospectively studied the medical records and analyzed the follow-up information of 53 patients who have done surgery for skull-base meningiomas with extracranial extensions in West China Hospital of Sichuan University from 2009 to 2020.

Results

The incidence of skull-base meningiomas with extracranial extensions was 0.74%. The average diagnosis age was 45.9 years, with a 1:3.1 men to women ratio. WHO grade I was seen in 84.9% of patients, and higher grades were found in 15.1%. Heterogeneous enhancement, high bone invasion rate, high incidence of peritumoral edema, and high dural tail sign rate were typical imaging features. Routine craniotomy and endoscopic endonasal approach were adopted, and gross total resection was performed in 62.3% of cases with 20.8% postoperative complication rates. The average follow-up time was 61.5 months, with a recurrence rate of 34.9%. By survival analysis, the extent of resection (p = 0.009) and the histological grade (p = 0.007) were significantly related to the prognosis. Adjuvant radiotherapy proved beneficial in patients with subtotal resection (p = 0.010) and high-grade meningiomas (p = 0.018).

Conclusions

Skull-base meningiomas with extracranial extensions were sporadic. According to the tumor location and communication way showed by the preoperative imaging, routine craniotomy or endoscopic endonasal approach with a reasonable skull-base repair strategy could be adopted to achieve the maximum tumor resection. Maximized resection, adjuvant radiotherapy, and low histological grade indicate a better prognosis.

Extent of Resection Research in Skull Base Neurosurgery: Previous Studies and Future Directions

Surgery is the first-line therapy for most benign and malignant skull base tumors. Extent of resection (EOR) is a metric commonly used for preoperative surgical planning and to predict risk of postoperative tumor recurrence. Therefore, understanding the evidence on EOR in skull base neurosurgery is essential to providing optimal care for each patient. Several studies from the skull base neurosurgery literature have presented investigations of various topics related to EOR, including 1) preoperative EOR scoring systems, 2) intraoperative EOR scoring systems, 3) EOR and tumor recurrence, and 4) EOR and functional outcomes. We propose that future investigations should focus on the following elements to improve EOR research in skull base neurosurgery: 1) multi-institutional collaboratives with treatment propensity matching; 2) expert consensus and mixed-methods study design; and 3) predictive analytics/machine learning. We believe that these methods offer several advantages that have been described in the literature and that they address limitations of previous studies. The aim of this review was to inform future study design and improve the overall quality of subsequent investigations on EOR in skull base neurosurgery.

Functional histology of human scrotal wall layers and their overlooked relation with infertility: a narrative review

Male infertility currently contributes to nearly half of the reported infertility cases. Scrotal wall layers play a cardinal role in regulating testicular physiology. However, few studies have focused on the functional histology of these layers and their relations with infertility in humans. The objective of the present narrative review is to collate novel insights into the functional histology of the human scrotal wall layers and their relation with infertility. The data was extracted from articles published between 1946 and 2021. The study was performed between January and December 2021. 71 original studies have been included in this review. Despite the fact that few studies have presented detailed functional histology of the human scrotal wall layers, this narrative review elucidates the possible influence of scrotal histology on infertility. Scrotal wall layers-associated pathologies may induce infertility by various mechanisms. They can impose mechanical forces that may affect the testicular histology and stimulate testicular inflammation. Moreover, they may induce testicular hyperthermia. Various unanswered clinical questions have been identified in this narrative review. More clinical studies are needed to assess the effect of alterations in the components of the scrotal wall layers on fertility (e.g., due to the exposure to metabolic and/or psychological stressors). In addition, testing the effectiveness of various pharmacological/surgical interventions to treat scrotal wall layers-associated pathologies will provide more insights into infertility treatment.

Augmented-reality template guided transorbital approach for intradural tumors

For “minimally invasive” approaches to a deep-lying skull base lesion, the bone opening must be precisely placed and adequately wide to accomplish the surgical goal. Surgical rehearsal in virtual reality (VR) can generate navigation-integrated augmented reality (AR) templates to ensure precise surgical openings.

In this video, the authors used AR templates for the transpalpebral, transorbital approach for intradural tumors. VR renderings of patient-specific anatomy were used in surgical rehearsal. The optimal openings were saved and, at surgery, projected into the eyepiece of the navigation-tracked microscope. The template enhanced the planning of the incision and soft-tissue exposure and guided the drill toward the target.

The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21172

Eyebrow incision with a crescent-shaped orbital rim craniotomy for microscopic and endoscopic transorbital approach to the anterior and middle cranial fossa: A cadaveric study and case presentation

•

The transorbital approach combining eyebrow incision and crescent-shaped craniotomy increases the surgical freedom to access the anterior and middle skull-base.

•

The technic allows the use of both endoscope and microscope.

•

The concept is at the crossroad between the supraorbital keyhole and endoscopic trans-orbital approach.

Surgical Treatment of Intraorbital Lesions

BACKGROUND

Resection of pure intraorbital tumors is challenging owing to the nearness of the optic apparatus. The objective of this article was to report our experience with different intraorbital tumors and discuss classic approaches and obstacles.

METHODS

A retrospective case series of patients who underwent surgery for intraorbital tumors at a tertiary neurosurgical center between June 2007 and January 2020 was performed.

RESULTS

The study included 34 patients (median age 58 years; range, 18-87 years; 55.9% [19/34] female, 44.1% [15/34] male). Preoperative proptosis was observed in 67.6% (23/34); visual impairment, in 52.9% (18/34); diplopia, in 41.2% (14/34); and ptosis, in 38.3% (13/34). Intraconal tumors were found in 58.8% (20/34). The most common lesions were cavernous hemangiomas in 26.5% (9/34) and metastases in 14.7% (5/34). Gross total resection rate was 73.5% (25/34). Planned biopsy was performed in 14.7% (5/34). Median follow-up time was 15.5 months (interquartile range: 0-113 months). Surgical approaches included supraorbital approach (23.5% [8/34]), pterional approach (52.9% [18/34]), lateral orbitotomy (14.7% [5/34]), transnasal approach (5.9% [2/34]), and combined transnasal approach/lateral orbitotomy (2.9% [1/34]). Excluding planned biopsies, gross total resection was achieved in 80.0% (12/15) with pterional approach, 100% (7/7) with supraorbital approach, 80.0% (4/5) with lateral orbitotomy, and 100% (1/1) with transnasal approach/lateral orbitotomy. Complication rate requiring surgical intervention was 11.8% (4/34).

CONCLUSIONS

Considering the low operative morbidity and satisfactory functional outcome, gross total resection of intraorbital lesions is feasible. We support use of classic transcranial and transorbital approaches. More invasive and complicated approaches were not needed in our series.

Advances in Multidisciplinary Management of Skull Base Meningiomas

The surgical management of Skull Base Meningiomas (SBMs) has radically changed over the last two decades. Extensive surgery for patients with SBMs represents the mainstream treatment; however, it is often challenging due to narrow surgical corridors and proximity to critical neurovascular structures. Novel surgical technologies, including three-dimensional (3D) preoperative imaging, neuromonitoring, and surgical instruments, have gradually facilitated the surgical resectability of SBMs, reducing postoperative morbidity. Total removal is not always feasible considering a risky tumor location and invasion of surrounding structures and brain parenchyma. In recent years, the use of primary or adjuvant stereotactic radiosurgery (SRS) has progressively increased due to its safety and efficacy in the control of grade I and II meningiomas, especially for small to moderate size lesions. Patients with WHO grade SBMs receiving subtotal surgery can be monitored over time with surveillance imaging. Postoperative management remains highly controversial for grade II meningiomas, and depends on the presence of residual disease, with optional upfront adjuvant radiation therapy or close surveillance imaging in cases with total resection. Adjuvant radiation is strongly recommended in patients with grade III tumors. Although the currently available chemotherapy or targeted therapies available have a low efficacy, the molecular profiling of SBMs has shown genetic alterations that could be potentially targeted with novel tailored treatments. This multidisciplinary review provides an update on the advances in surgical technology, postoperative management and molecular profile of SBMs.

Endoscopic sublabial transmaxillary approach to the inferior orbit: pearls and pitfalls-A comparative anatomical study

OBJECTIVE

Although orbital surgery has always represented a challenge for neurosurgeons, keyhole and endoscopic techniques are gradually surging in popularity maximizing functional and esthetic outcomes. This quantitative anatomical study first compared the surgical operability achieved through three endoscopic approaches within the inferior orbit: the endoscopic sublabial transmaxillary (ESTMax), the endoscopic endonasal transethmoidal (EETEth), and the endoscope-assisted lateral orbitotomy (ELO).

METHODS

Each of these approaches was performed bilaterally on five specimens. We described the ESTMax step-by-step, underlining its advantages and pitfalls in comparison with EETEth and ELO. Then, we assessed surgical measurements and operability in ESTMax, EETEth, and ELO.

RESULTS

The ESTMax provided the most favorable operative window (278.9 ± 43.8 mm²; EETEth: 240.8 ± 21.5 mm², p < 0.001; ELO: 263.1 ± 19.8 mm², p = 0.006), the broadest surgical field area (415.9 ± 26.4 mm²; EETEth: 386.7 ± 30.1 mm², p = 0.041; ELO: 305.2 ± 26.3 mm², p < 0.001), surgical field depths significantly shorter than EETEth (p < 0.001) but similar to ELO, the widest surgical angles of attack (45°-65°; EETEth: 20°-30°, p < 0.001; ELO: 25°-50°, p < 0.001), and the greatest surgical mobility areas (EETEth: p < 0.001; ELO: p < 0.001). Furthermore, the ESTMax allowed multi-angled exposure and handy maneuverability around all the inferior intraorbital targets. Small anterior antrostomy, blunt intraorbital dissections, direct targets' approach, orbital floor reconstruction, and maxillary bone flap replacement may limit the ESTMax morbidity rates.

CONCLUSIONS

The ESTMax is a minimally invasive "head-on" orbital approach that exploits endoscopic surgery advantages avoiding the cranio-orbital and trans-nasal approach limitations and possible complications. It represents a promising alternative to EETEth and ELO because of its optimal operability for resecting lesions extending into the entire inferior orbit.

Progressive Orbitotomy and Graduated Expansion of the Supraorbital Keyhole: A Comparison with Alternative Minimally Invasive Approaches to the Paraclinoid Region

BACKGROUND

Various minimally invasive approaches, such as supraorbital (SO), minipterional (MPT), and translateral orbital (TLO), can access the paraclinoid region. Studies have described these approaches individually but have not directly compared all of them in the same anatomic specimen.

METHODS

Using virtual reality models generated from computed tomography studies of living subjects, we simulated TLO, MPT, and variations of SO approaches, without and with removal of the orbital rim and sphenoid wing. We measured the area of freedom (AOF), distance, and angle of attack to 4 paraclinoid targets: anterior clinoid process, optic foramen, lateral superior orbital fissure, and maxillary strut.

RESULTS

For superiorly positioned targets, such as anterior clinoid process and optic foramen, MPT provided a larger AOF compared with the supraorbital approach. However, with progressive drilling of the orbital roof and lesser wing of the sphenoid, the SO corridor AOF was equivalent to MPT at the anterior clinoid process and larger at the optic foramen (P = 0.003). To the lateral superior orbital fissure, TLO had the most limited AOF, and MPT had the greatest (P < 0.01 for all comparisons). For the maxillary strut, MPT, TLO, and SO with orbitotomy and sphenoidectomy all provided a similar AOF.

CONCLUSIONS

For surgical targets in the paraclinoid region, MPT provided a greater AOF and shorter distance compared with TLO and limited SO approaches. With progressive enlargement of the SO corridor, SO with orbitotomy and sphenoidectomy matched and occasionally superseded the AOF of MPT. However, the AOF to inferomedial targets such as the maxillary strut was similar among all approaches.

Transconjunctival Extirpation of a Voluminous Orbital Cavernoma: 2-Dimensional Operative Video

Purely intraorbital cavernomas remain rare, but still are the most common benign orbital tumors.1 These expansive lesions are now rapidly detected and adequately treated. Surgical resection is the gold standard and a definitive solution. The choice of approach varies between different possibilities, including orbitotomies, trans-sinusal routes, and transconjunctival accesses.2-4 Because the last technique is less known to the neurosurgeon, we describe here a step-by-step guide to perform it.

 The technique is illustrated with the case of a 62-yr-old male with a voluminous right retroocular cavernoma. He presented a progressive right exophthalmia without visual acuity or campimetric deterioration. Because the cavernoma was purely medial from the optic nerve in the intraconal space, no osteotomy was deemed necessary to extirpate the lesion. The video shows the conjunctival dissection, followed by the medial rectus muscle being dissected, allowing us to attain the retrobulbar space in the orbit. The cavernoma is then dissected from the surroundings and reduced in volume by coagulation so its removal does not apply hyperpressure on the adjacent fragile structures. We then pursue with the closure by stitching the medial rectus muscle to the eyeball. Finally, the conjunctiva is sutured.

 Postoperatively, there was no complication. A transient mydriasis due to ciliary nerve manipulation spontaneously resolved. Extirpation of the lesion was total. The patient's exophthalmia normalized over the next months. No visual or campimetric deterioration was noted at follow-up. A slight horizontal diplopia was noted after surgery, which normalized at 1 yr. The patient's consent was obtained for the procedure.