Advantages and limitations of endoscopic endonasal approaches to the skull base

Conventional clinical signs and symptoms are poor predictors of postoperative cerebrospinal fluid leak: A single-centre cohort perspective

BACKGROUND

Postoperative cerebrospinal fluid (CSF) leak remains a concerning complication of the endoscopic endonasal approach (EEA) for skull base pathology. Signs and symptoms suggesting CSF leak often trigger additional workup during the postoperative course. We systematically evaluate associations between subjectively reported clinical signs/symptoms noted during the immediate postoperative period and incidence of postoperative CSF leaks.

METHODS

Retrospective chart review was conducted at a tertiary academic medical centre including 137 consecutive patients with intraoperative CSF leak during EEA with primary repair between July 2018 and August 2022. Postoperative CSF leak associations with clinical signs and symptoms were evaluated using positive (PPV) and negative predictive values (NPV), sensitivity, specificity and odds ratio (OR) via univariate logistic regression.

RESULTS

Seventy-nine patients (57.7%) had high-flow leaks repaired and 5 (3.6%) developed CSF leaks postoperatively. Of reported symptoms, rhinorrhea was most common (n = 52, 38.0%; PPV [95% CI] = 7.6% [4.8%, 11.9%]), followed by severe headache (n = 47, 34.3%; 6.3% [3.1%, 12.5%]), dizziness (n = 43, 31.4%; 2.3% [0.4%, 12.1%]), salty or metallic taste (n = 20, 14.6%; 9.9% [3.3%, 25.8%]), and throat drainage (n = 10, 7.3%; 9.9% [1.7%, 41.4%]). Nausea or vomiting constituted the most reported sign concerning for CSF leak (n = 73, 53.3%; PPV [95% CI] = 4.1% [2.0%, 8.1%]). On univariate regression, no sign or symptom, including rhinorrhea (OR [95% CI] = 7.00 [0.76-64.44]), throat drainage (3.42 [0.35-33.86]), salty/metallic taste (4.22 [0.66-27.04]), severe headache (3.00 [0.48-18.62]), dizziness (0.54 [0.06-4.94]), fever (3.16 [0.50-19.99]), and nausea/vomiting (1.33 [0.22-8.21]), associated with postoperative CSF leak.

CONCLUSIONS

A range of subjectively reported symptoms and signs failed to predict postoperative CSF leak. Further investigation is warranted to inform appropriate attention and response.

Comparative Anatomy of the Contralateral Transmaxillary Approach Alone and With Ipsilateral Transpterygoid Extension: Quantitative Insights on Surgical Exposure and Maneuverability in the Petroclival Region

BACKGROUND AND OBJECTIVES

Beyond qualitative evidence legitimizing endoscopic corridors through contralateral transmaxillary (CTM) and endonasal ipsilateral transpterygoid (ITP) corridors to the petrous apex and petroclival region, surgical feasibility by direct quantitative comparative anatomy is sparse. Our cadaveric study addresses this by performing the CTM approach followed by ITP extension to quantify the extent of petrous apex resection, instrument maneuverability, and working distance to petrous apex.

METHODS

Anatomic dissections were performed bilaterally on 5 latex-injected human cadaveric heads (10 petrous bones). After CTM dissections were quantified, the ITP approach was added enlarging initial exposure. Differences were measured with statistical significance when P values are < .05.

RESULTS

The mean petrosectomy volume was 0.958 cm3 with CTM and 1.987 cm3 with CTM + ITP, corresponding to 14.53% and 30.52% petrous apex resection, respectively. Craniocaudal instrument mobility was more limited in the lateral extent of dissection compared with the midline for both CTM (8.062° vs 14.416°) and CTM + ITP (5.4° vs 14.4°). The CTM approach achieved the lateral-most dissection at the body of the petrous apex (15.936 mm), with lateralization more limited in the superior petroclival region (9.628 mm) and the inferior petroclival region (8.508 mm). Angle of surgical maneuverability increased superiorly vs inferiorly in the CTM approach (mean 12.596° vs 8.336°, respectively). The CTM approach offered the shortest mean working distance (88.624 mm) to the petroclival region compared with the bi-nares approach (100.5 mm). CTM + ITP achieved greater lateralization in the superior (21.237 mm) and inferior (22.087 mm) aspects of the petroclival region compared with the CTM approach.

CONCLUSION

Operative considerations are discussed in accessing target neurovascular structures through the uniquely shaped corridors formed by the CTM or combined CTM + ITP. Allowing mobilization of the internal carotid artery laterally and eustachian tube inferiorly, addition of the ITP allowed for larger petrosectomy than CTM alone, especially in the inferior and lateral aspects of the petrous bone.

Surgical outcomes in patients with acromegaly: Microscopic vs. endoscopic transsphenoidal surgery

Transsphenoidal resection of growth hormone-secreting pituitary neuroendocrine tumors remains the first-line treatment for acromegaly. This can be performed through microsurgery or endoscopic surgery. For the past decades, endoscopic surgery has become the preferred technique in an increasing number of centers worldwide. However, whether it offers superior clinical outcomes has yet to be determined. In this paper, we performed a narrative review of the literature comparing both techniques in the treatment of acromegaly. We critically assessed available comparative studies from an objective perspective to determine their suitability for defining superiority of either technique. Available evidence displays substantial methodological variations and reports conflicting findings. Although endoscopic surgery provides a wider exposure and enhanced visibility of the surgical field, this does not consistently translate into better clinical outcomes, as most tumors are equally accessible through both techniques. Postoperative outcomes such as remission and complication rates are similar between both techniques. The management of acromegaly should be performed by experienced pituitary neurosurgeons, regardless of the approach. The involvement of a multidisciplinary team in a dedicated pituitary center is critical to ensure optimal outcomes.

Case report: Endoscopic endonasal transposterior clinoid approach for resection of posterior clinoid process meningioma: technical notes and literature review

Background

Posterior clinoid process (PCP) meningioma is an exceedingly rare entity. It remains the most challenging skull base lesion for neurosurgeons due to its treacherous location that insinuates amongst critical neurovascular structures. This article will describe the technical notes using the endoscopic endonasal approach that provide the earliest devascularization and detachment of the tumor PCP meningioma.

Methods

We are introducing the surgical implementation of an endoscopic endonasal approach to removing PCP meningioma. Furthermore, we perform a literature review of posterior clinoid process meningioma that undergoes surgical intervention, then summarize the benefits and limitations of each approach.

Results

We present a case of right PCP meningioma that was removed using an endoscopic endonasal approach through the transposterior clinoid corridor in a 52-year-old-woman. We describe the technical notes in performing this approach to have the earliest devascularization and detachment of the tumor by performing posterior clinoidectomy. Safe tumor removal is performed with a wide and clear view of the surrounding neurovascular structure. Based on our database search, we found nine articles reported on the surgical management of PCP meningiomas, with a total number of 15 cases. All of the reported cases performed the tumor removal using the transcranial approach.

Conclusion

The endoscopic endonasal transposterior clinoid approach circumvents all disadvantages faced by the traditional transcranial approach, providing the earliest approach to devascularized and detaching the tumor from its attachment at PCP. This approach demonstrates safety and efficacy, making it an acceptable alternative for PCP meningioma resections.

Are the Ethmoidal Foramina Through the Frontal Bone, Ethmoid Bone, or Frontoethmoidal Suture?

INTRODUCTION

To investigate the locations of the anterior, middle, and posterior ethmoidal foramina and their relationships to the frontoethmoidal suture.

METHODS

One hundred twenty sides from sixty adult human skulls were used. Specimens with significant damage to the medial orbit wall were excluded. The number of ethmoidal foramina (anterior, middle, and posterior) on the medial orbital wall and the relationship of each foramen to the frontoethmoidal suture were recorded and classified as follows: Type I: superior to the frontoethmoidal suture; Type II: on the frontoethmoidal suture; Type III: inferior to the frontoethmoidal suture.

RESULTS

Of the ninety-four sides, fourteen (14.9%) had one foramen, sixty-two (66.0%) had two , and eighteen (19.1%) had three. In total, 192 ethmoidal foramina were observed. Among the fourteen sides with one foramen, eight foramina were anterior and six were posterior. Among the 192 ethmoidal foramina, 162 were eligible for fur ther classification (74 anterior, 14 middle, and 74 posterior). Types I, II, and III ethmoidal foramina were found in 38.3% (62/162), 61.7% (100/162), and 0% (0/162), respectively.

CONCLUSIONS

Our current study found a higher incidence of type I than previously reported. It is important to be aware of the significant incidence of foramen variations when the medial orbit wall is manipulated during surgery. Unless caution is observed, an inadvertent surgical injury can occur and lead to life-threatening complications. Therefore, a good understanding of orbital anatomy and its potential variations is critical for improving patient out comes.

Interdisciplinary Management of Skull Base Tumors

OBJECTIVE

Endoscopic endonasal skull base surgery has gained acceptance worldwide. Comparative analysis has demonstrated that endoscopic skull base surgery may have advantages for many pathologies of the anterior skull base, e. g., sinonasal malignant tumors; pathologies of the central skull base, e. g., pituitary adenomas, craniopharyngiomas; well-selected cases of planum sphenoidale and tuberculum sellae meningiomas; or for clival lesions, e. g., chordomas, chondrosarcomas, or selected meningiomas. Over the past three decades, interdisciplinary surgical teams, consisting of otolaryngologists and neurosurgeons, have provided detailed anatomical knowledge, suggested new approaches or modifications of established surgical techniques, and offered continued surgical education.

METHOD

A review of pertinent literature was conducted with an emphasis on interdisciplinary endoscopic surgery of skull base lesions.

RESULTS

Based on the authors̓ surgical experience in two different interdisciplinary endoscopic skull base centers, the authors classify approaches for endoscopic endonasal skull base surgery, describe indications, and key anatomic landmarks for common pathologies, and highlight surgical techniques to avoid complications.

CONCLUSION

Interdisciplinary endonasal endoscopic surgery combines surgical expertise, improves resection rates for many pathologies, and minimizes morbidity by reducing the incidence of surgical complications.

Endoscopic trans-eustachian tube approach: identifying the precise landmarks, a novel radiological and anatomical evaluation

PURPOSE

The endoscopic trans-eustachian approach (ETETA) is a less invasive approach to the infratemporal fossa (ITF), providing superior exposure compared to traditional transcranial approaches. The anatomy of the pharyngotympanic (eustachian) tube and adjacent neurovascular structures is complex and requires in-depth knowledge to safely perform this approach. We present a cadaveric and radiological assessment of critical anatomic considerations for ETETA.

METHODS

Six adult cadaveric heads were dissected alongside examination of 50 paranasal sinus CT scans. Key anatomic relationships of the pharyngotympanic tube and adjacent structures were qualitatively and quantitatively evaluated. Descriptive statistics were performed for quantitative data.

RESULTS

Anatomical and radiological measurements showed lateralization of the pharyngotympanic tube allows access to the ITF. The pharyngotympanic tube has bony and cartilaginous parts with the junction formed by the sphenoid spine and foramen spinosum. The bony part and tendon of the tensor tympani muscle were located at the posterior genu of the internal carotid artery. The anterior and inferior wall of the carotid canal was located between the horizontal segment of the internal carotid artery and petrous segment of the cartilaginous pharyngotympanic tube.

CONCLUSION

The combination of preoperative radiographic assessment and anatomical correlation demonstrates a safe and effective approach to ETETA, which allowed satisfactory visualization of ITF. The morphological evaluation showed that the lateralization of the pharyngotympanic tube and related structures allowed a surgical corridor to reach the ITF. Endoscopic surgery through the pharyngotympanic tube is challenging, and in-depth understanding of the key anatomic relationships is critical for performing this approach.

[Endoscopic endonasal anterior skull base surgery : Presentation of a monocentric entity profile]

BACKGROUND

Extended endoscopic endonasal surgery (EEES) is an essential part of treatment of various pathologies of the anterior skull base. In addition to significant improvements in the quality of life of affected patients and a lower complication profile compared to open skull base surgery, the therapeutic results are comparable if the indications are correct.

MATERIALS AND METHODS

Data of all endoscopic endonasal skull base procedures performed at the University Skull Base Center Hamburg under the direction of the Department of Otorhinolaryngology between June 2018 and November 2022 were retrospectively collected.

RESULTS

A total of 50 cases were identified. Of these, 56% (28/50) were malignant tumors, 24% (12/50) were benign pathologies with direct skull base involvement, and 20% (10/50) were anterior skull base defects with rhinoliquorrhea. In 96% (48/50) of cases, the preoperatively set goal of surgery (representative biopsy, complete resection, closure of the skull base defect) could be achieved. Complications grade III or higher according to Clavien-Dindo occurred in 4/50 cases. During the observation period, n = 5 olfactory neuroblastomas were diagnosed, all of which were exclusively and successfully operated on endoscopically.

CONCLUSION

In recent years, the spectrum of endoscopically resectable pathologies of the anterior skull base has steadily expanded. In particular, midline-related tumors such as olfactory neuroblastoma or iatrogenic/idiopathic skull base defects with cerebrospinal fluid rhinorrhea are treated completely endoscopically with very good results. Nevertheless, there are also limitations to this technique. Due to high variance in the scope of frontobasal surgery, the extent, and the complex anatomy, as well as the overlapping responsibilities of the specialist disciplines, establishment of certified skull base centers and bundling of frontobasal surgery at these centers is highly relevant for quality assurance.

Endoscopic Endonasal Transpterygoid Approach and the Need for Myringotomy

OBJECTIVE

The expanded endonasal transpterygoid approach (EETA) is used to access the middle and posterior fossa through the pterygoid process. Traditionally, the eustachian tube (ET) was resected during EETA, which often required subsequent myringotomy for inner ear drainage. Anterolateral transposition of the ET was proposed to decrease potential morbidity associated with resection. However, a comparison of resection versus transposition regarding the need for subsequent myringotomy has not been reported.

METHODS

This is a retrospective cohort study of patients who underwent an EETA. Patient demographics, tumor characteristics, management of ET with resection versus transposition, and need for subsequent myringotomy were collected. Analysis was performed with JMP software in standard fashion and univariate and multivariate logistic regression analysis performed with a p < 0.05 was considered significant.

RESULTS

Ninety-one patients underwent EETA for various malignant and benign tumors. Twenty-seven patients required myringotomy, with tumors of the pterygopalatine fossa accounting for the most common location (n = 8). Malignant pathology had the highest myringotomy rate compared to benign tumors (48.9% vs. 10.9%, p < 0.001), as did receiving postoperative radiation (p < 0.001), ET resection (p < 0.001), and increasing CPK class. Multivariate analysis of these variables suggests that only ET resection significantly correlated with the need for myringotomy (LR 7.97, p = 0.005).

CONCLUSIONS

ET resection during EETA can lead to ET dysfunction and require myringotomy post-operatively, and patients should be counseled of this risk. Radiation treatment, malignant pathology, and CPK class, all reflecting situations where more extensive surgery was needed, were associated with the need for myringotomy on univariate analysis but did not reach significance with multivariate analysis.

LEVEL OF EVIDENCE

4 Laryngoscope, 134:1203-1207, 2024.

Clinical study on the selection of endoscopes and microscopes for transsphenoidal surgery of non-aggressive pituitary macroadenoma and microadenoma and the influencing factors of hyposmia after endoscopic transsphenoidal surgery

Background and objective

Transsphenoidal surgery, including endoscopic and microscopic resection, is the first choice of treatment for pituitary tumors. With the widespread application of neuroendoscopy in recent decades, there has been a trend to replace microscopes. In clinical practice, we have found that in transsphenoidal surgery for non-invasive microadenomas and macroadenomas, microscopy can achieve a higher total resection rate, shorter operation time, lower incidence of postoperative complications, and faster recovery of olfaction. This study aimed to explore the selection of endoscopes and microscopes for non-aggressive transsphenoidal surgery for pituitary adenomas and the factors affecting olfactory recovery.

Methods

From August 2019 to October 2022, 93 patients with non-aggressive microadenomas and macroadenomas via the transsphenoidal approach were selected from the First Affiliated Hospital of Harbin Medical University and treated with rich experience in pituitary tumor subspecialty microscopy and endoscopic surgery. Different surgical methods were used to divide the patients into microscopic (n = 35) and endoscopic (n = 58) groups. The total tumor removal rate, intraoperative blood loss, operation time and cost, postoperative hospital stay, recovery of visual function, postoperative changes in hormone levels, complication rate, and recovery from complications 3 months after the operation were compared between the two groups.

Results

There were no significant differences in the tumor removal rate, postoperative visual acuity, and visual field recovery between the two groups (p > 0.05). There was a significant difference in the recovery rate of olfactory function between the two groups 3 months after the operation (p < 0.05), and there was no significant difference in the incidence of other complications (p > 0.05); Compared with the two groups, the microscope group had shorter operation time, longer postoperative hospital stay, less average operation cost and less blood loss, and the difference was statistically significant (p < 0.05). The position of the nasal septum mucosal flap incision was a risk factor for hyposmia 3 months after the operation.

Conclusion

Microsurgery and endoscopic surgery are suitable surgical treatments for nonaggressive microadenomas and macroadenomas. The total tumor removal and postoperative hormone remission rates of the two surgical methods were approximately the same. However, the microsurgery group had a shorter operation time, less intraoperative blood loss, faster olfactory function recovery, and a lower average operation cost. The position of the nasal septal mucosal flap incision was a risk factor for hyposmia at 3 months postoperatively. Hyposmia is less likely to occur when the superior edge of the nasal septal mucosal flap incision is not higher than the lower edge of the ipsilateral superior turbinate.

Comparison of the Endoscopic Endonasal Approach with the Endoscopic Supraorbital Keyhole Approach to the Tuberculum Sellae Region: A Quantitatively Cadaveric Study

BACKGROUND

 The endoscopic endonasal approach (EEA) and the endoscopic supraorbital keyhole approach (eSKA) provide minimally invasive access to tuberculum sellae (TS) tumors. Evaluation of the operating maneuverability is helpful for approach selection. Herein, we compared the two approaches and aimed to provide quantitative anatomic data for surgical decision-making in the management of TS lesions.

METHODS

 Fifteen dissections were performed on five silicone-injected cadaveric heads. The EEA and eSKA (both right and left) were performed on each head. Surgical freedom and working angles in the axial and sagittal planes were calculated using the stereotactic navigation system in the selected six targets: the midpoint of the leading edge of the sphenoid sinus (leSS), the midpoint of the edge of the dorsum sellae (eDS), the ipsilateral medial opticocarotid recess (imOCR), the contralateral medial opticocarotid recess (cmOCR), the ipsilateral lateral opticocarotid recess (ilOCR), and the contralateral lateral opticocarotid recess (clOCR).

RESULTS

 The surgical freedom at the ilOCR and the axial working angles at the leSS, ilOCR, and imOCR (imOCR with excessive manipulation of the optic apparatus) were greater in the eSKA. The EEA provided greater surgical freedom and/or working angles at most targets than eSKA (the surgical freedom at the imOCR, cmOCR, clOCR, and eDS; the axial working angles at the cmOCR and clOCR; and the sagittal working angles at the leSS, imOCR, cmOCR, clOCR, and eDS).

CONCLUSION

 The EEA provides greater surgical freedom and working angles for paramedian lesions, whereas the eSKA provides better surgical maneuverability for lesions with lateral extension.

Current and Future Perspectives of Microscopic and Endoscopic Transsphenoidal Surgery for Pituitary Adenomas: A Narrative Review

Transsphenoidal resection remains the standard treatment for most pituitary adenomas. However, the ideal surgical approach to safely access these lesions, either microsurgical or endoscopic, continues to be debated. Since the introduction of endoscopic transsphenoidal surgery, centers around the world have increasingly adopted this technique, experiencing a shift away from the conventional microsurgical approach. Large series reporting the efficacy and safety of endoscopic surgery have fueled a growing interest in comparing clinical outcomes between both approaches. Still, proving superiority of either surgical approach remains an elusive task due to the inherent drawbacks of surgical observational studies, as we are still faced with a growing body of evidence reporting conflicting results. Thus, a comprehensive discussion regarding the reach and limitations of both techniques becomes necessary. In this narrative review, we perform a critical appraisal of the literature and provide an expert opinion on the state-of-the-art in transsphenoidal surgery for pituitary adenomas. The advantages and limitations of each approach are assessed and compared from a technical standpoint, and their reported outcomes evaluated in the framework of this transition phase. Available evidence should be interpreted in light of individual patient characteristics and within the context of each medical center, taking into consideration the known impact that surgical expertise and multidisciplinary management hold on clinical outcomes.

An endoscopic transnasal prelacrimal recess transmaxillary approach to the pterygopalatine fossa and infratemporal fossa

Objective

In this paper, the goal of the authors is to present the anatomic nuances and their clinical experience with lesions of the pterygopalatine fossa and infratemporal fossa using an endoscopic transnasal prelacrimal recess transmaxillary approach (PLRMA).

Methods

An endoscopic anatomical dissection of three fresh cadaveric heads was performed bilaterally to evaluate the feasibility of the PLRMA. Prior to dissection, stereotactic computed tomography scans were obtained for each head to obtain anatomical measurements. The area of exposure on the posterior wall of the maxillary sinus was determined using stereotaxis. The cases of six patients with schwannomas or epidermoid cysts who underwent the transnasal PLRMA were illustrated.

Results

The mean area of exposure on the posterior wall of the maxillary sinus was 9.55 cm2. Total resection was achieved in all six patients. The mean follow-up time was 16 months, and one patient complained of postoperative facial numbness, which resolved gradually. No cases of chronic sinusitis were reported.

Conclusions

The endoscopic transnasal PLRMA provides efficient operative exposure to the pterygopalatine fossa and infratemporal fossa. Preserving the integrity of the mucosa on the nasal lateral wall is an advantage of this approach.

Impact of Concurrent Chronic Rhinosinusitis on Complication Rates after Endonasal Endoscopic Skull Base Surgery: A Single-Center Experience

Objectives  Preoperative planning of endoscopic skull base surgery (ESBS) is essential. The safety of performing surgery before managing sinus pathologies including concurrent chronic rhinosinusitis (CRS) in patients undergoing ESBS has been questioned. The current study aimed to evaluate and compare the complication rates between patients with and without CRS undergoing ESBS. Design  This is a retrospective study. Setting  Present study was conducted at tertiary referral center. Participants  We included all patients who underwent ESBS between March 2015 and March 2021. However, patients who had surgical revision for remnant tumor, primary sinonasal tumor excision, and cerebrospinal fluid (CSF) leakage repair were excluded. The presence of concurrent CRS was determined according to the European Position Paper on Rhinosinusitis and Nasal Polyps 2020 (EPOS 2020) criteria by reviewing electronic charts about the preoperative clinical assessment and CT scan images of the paranasal sinuses. Then, the incidence rates of postoperative meningitis, CSF leakage, and surgical site infection were compared between patients with and without concurrent CRS undergoing ESBS. Main Outcome Measures  Postoperative complication rates in patients underwent ESBS with and without CRS. Results  From a total of 130 ESBS cases, 99 patients were included in this study. Among them, 24 had concurrent CRS. One patient presented with postoperative meningitis, one with CSF leakage, and two with surgical site infections. The incidence rate of postoperative meningitis, CSF leakage, and surgical site infection did not significantly differ between patients with and without concurrent CRS. Conclusion  Concurrent CRS is not a contraindication for ESBS. Moreover, simultaneous endoscopic sinus surgery can safely be performed without additional morbidity in ESBS.

Otolaryngology Considerations of Pituitary Surgery: What an Endocrinologist Should Know

Endoscopic endonasal skull base surgery is the preferred surgical approach for the management of pituitary adenomas. Perioperative management of pituitary lesions requires multidisciplinary care and typically includes a dual surgeon team consisting of a neurosurgeon and an otolaryngologist. The involvement of the otolaryngologist allows for a safe surgical approach with excellent intraoperative visualization of the tumor to enable an effective resection of the tumor by the neurosurgeon. Detection and treatment of sinonasal pathology is essential prior to surgery. Patients may experience sinonasal complaints following endoscopic transsphenoidal surgery, although this is typically temporary. Sinonasal care in the postoperative period can expedite recovery to baseline. Here we discuss the perioperative factors of endoscopic pituitary surgery that endocrinologists should be aware of, ranging from preoperative patient selection and optimization to postoperative care, with a particular emphasis on anatomic and surgical factors.

Craniovertebral Junction Instability after Oncological Resection: A Narrative Review

The craniovertebral junction (CVJ) is a complex transition area between the skull and cervical spine. Pathologies such as chordoma, chondrosarcoma and aneurysmal bone cysts may be encountered in this anatomical area and may predispose individuals to joint instability. An adequate clinical and radiological assessment is mandatory to predict any postoperative instability and the need for fixation. There is no common consensus on the need for, timing and setting of craniovertebral fixation techniques after a craniovertebral oncological surgery. The aim of the present review is to summarize the anatomy, biomechanics and pathology of the craniovertebral junction and to describe the available surgical approaches to and considerations of joint instability after craniovertebral tumor resections. Although a one-size-fits-all approach cannot encompass the extremely challenging pathologies encountered in the CVJ area, including the possible mechanical instability that is a consequence of oncological resections, the optimal surgical strategy (anterior vs posterior vs posterolateral) tailored to the patient's needs can be assessed preoperatively in many instances. Preserving the intrinsic and extrinsic ligaments, principally the transverse ligament, and the bony structures, namely the C1 anterior arch and occipital condyle, ensures spinal stability in most of the cases. Conversely, in situations that require the removal of those structures, or in cases where they are disrupted by the tumor, a thorough clinical and radiological assessment is needed to timely detect any instability and to plan a surgical stabilization procedure. We hope that this review will help shed light on the current evidence and pave the way for future studies on this topic.

Fascia Lata: Another Workhorse for Complex Skull Base Reconstruction

BACKGROUND

Multiple methods exist for skull base reconstruction of defects created by expanded endonasal approaches. While the nasoseptal flap (NSF) has been well established as the workhorse of mucosal reconstruction in complex skull base defects in multi-layered closures, a variety of options exist for the inner layer of multilayer reconstruction, including fascia lata (FL).

OBJECTIVE

To present our experience and outcomes in utilizing FL in multiple ways to reconstruct a wide variety of complex skull base defects.

METHODS

Retrospective review was performed from May 2017 to February 2022 to identify 50 consecutive patients who underwent endoscopic skull base reconstruction using FL.

RESULTS

FL was employed for reconstruction in 50 patients included in the study: 37 undergoing primary expanded endonasal skull base surgery and 13 revision cases. A wide range of complex pathology was treated, with meningioma and craniopharyngioma being the two most common. FL was utilized as a "button" graft (34/50, 68.0%), free graft inlay/onlay (13/50, 26.0%), and as a button graft combined with onlay (3/50, 6.0%). Expanded surgery defects addressed included tuberculum sella/sphenoid planum (36/50, 72.0%), clivus (6/50, 12.0%), and cribriform/planum (8/50, 16.0%). Successful reconstruction with fascia lata was accomplished in 46/50 cases (92%), with only 4 cases (8%) requiring revision for post-op CSF leak. Donor-site complications were rare with only 1 case (2.0%) of post-op seroma.

CONCLUSION

FL, usually with NSF, offers a versatile option for the reconstruction of challenging defects with excellent outcomes and minimal morbidity. FL is emerging as a workhorse for reconstruction of the inner layer of complex skull base defects.

Pure endoscopic resection of pineal region tumors through supracerebellar infratentorial approach with 'head-up' park-bench position

OBJECTIVE

Neuroendoscopic resection via supracerebellar infratentorial (SCIT) approach is adequate for some indicated pineal region tumors with the natural infratentorial corridor. We described this full endoscopic approach through a modified 'head-up' park-bench position to facilitate the procedure.

METHODS

We reviewed the clinical and radiological data of four patients with pineal region lesions who underwent pure endoscopic tumor resection through the SCIT approach with this modified position. The related literature concerning fully endoscopic pineal region tumor resection was also reviewed.

RESULTS

This cohort included four patients with pineal region tumors. External ventricular drainage (Ommaya reservoir) was performed in three patients with hydrocephalus in advance. The average tumor volume was 19.2 ± 17.2 cm³. Pathological examination confirmed two mixed germinomas, one glioblastoma multiforme, and one hemangioblastoma. Gross total resection (GTR) was achieved in all patients, and all patients recovered well without neurological deficits or surgical complications. Hydrocephalus was relieved among all patients.

CONCLUSIONS

The pure endoscopic SCIT approach could enable safe and effective resection of pineal region tumors, even for relatively large lesions. The endoscope could provide a panoramic view and illumination of the deep-seated structures. Compared with the sitting position, this modified ergonomic position could be implemented easily.

The feasibility of three port endonasal, transorbital, and sublabial approach to the petroclival region: neurosurgical audit and multiportal anatomic quantitative investigation

PURPOSE

The petroclival region represents the "Achille's heel" for the neurosurgeons. Many ventral endoscopic routes to this region, mainly performed as isolated, have been described. The aim of the present study is to verify the feasibility of a modular, combined, multiportal approach to the petroclival region to overcome the limits of a single approach, in terms of exposure and working areas, brain retraction and manipulation of neurovascular structures.

METHODS

Four cadaver heads (8 sides) underwent endoscopic endonasal transclival, transorbital superior eyelid and contralateral sublabial transmaxillary-Caldwell-Luc approaches, to the petroclival region. CT scans were obtained before and after each approach to rigorously separate the contribution of each osteotomy and subsequentially to build a comprehensive 3D model of the progressively enlarged working area after each step.

RESULTS

The addition of the contralateral transmaxillary and transorbital corridors to the extended endoscopic endonasal transclival in a combined multiportal approach provides complementary paramedian trajectories to overcome the natural barrier represented by the parasellar and paraclival segments of the internal carotid artery, resulting in significantly greater area of exposure than a pure endonasal midline route (8,77 cm² and 11,14 cm² vs 4,68 cm² and 5,83cm², extradural and intradural, respectively).

CONCLUSION

The use of different endoscopic "head-on" trajectories can be combined in a wider multiportal extended approach to improve the ventral route to the most inaccessible petroclival regions. Finally, by combining these approaches and reiterating the importance of multiportal strategy, we quantitatively demonstrate the possibility to reach "far away" paramedian petroclival targets while preserving the neurovascular structures.

A Brief Explanation on Surgical Approaches for Treatment of Different Brain Tumors

The main goal of brain tumor surgery is to achieve gross total tumor resection without postoperative complications and permanent new deficits. However, when the lesion is located close or within eloquent brain areas, cranial nerves, and/or major brain vessels, it is imperative to balance the extent of resection with the risk of harming the patient, by following a so-called maximal safe resection philosophy. This view implies a shift from an approach-guided attitude, in which few standard surgical approaches are used to treat almost all intracranial tumors, to a pathology-guided one, with surgical approaches actually tailored to the specific tumor that has to be treated with specific dedicated pre- and intraoperative tools and techniques. In this chapter, the basic principles of the most commonly used neurosurgical approaches in brain tumors surgery are presented and discussed along with an overview on all available modern tools able to improve intraoperative visualization, extent of resection, and postoperative clinical outcome.

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 Current State of Visualization Techniques in Endoscopic Skull Base Surgery

Skull base surgery has undergone significant progress following key technological developments. From early candle-lit devices to the modern endoscope, refinements in visualization techniques have made endoscopic skull base surgery (ESBS) a standard practice for treating a variety of conditions. The endoscope has also been integrated with other technologies to enhance visualization, including fluorescence agents, intraoperative neuronavigation with augmented reality, and the exoscope. Endoscopic approaches have allowed neurosurgeons to reevaluate skull base neuroanatomy from new perspectives. These advances now serve as the foundation for future developments in ESBS. In this narrative review, we discuss the history and development of ESBS, current visualization techniques, and future innovations.

The Varied Presentations of Sinonasal Region Schwannomas: Apropos of Four Cases

Schwannomas of the sinonasal compartment are rare benign neoplasms of peripheral nerve sheath origin and constitute ~ 4% of all head and neck schwannomas. The presentation may simulate a range of benign and intermediate grade pathologies. Management involves surgical excision via open or endoscopic approach. To describe the clinico-epidemiological characteristics and surgical outcomes in sinonasal region schwannoma patients operated at our institute. The study is a descriptive case series of patients with sinonasal region schwannomas treated at our institution. A retrospective search of electronic database of the Department of ENT and Head and Neck Surgeries and Department of Pathology was conducted from January 2013 to January 2019. The various demographic and clinical details of the patients were extracted. A total of four patients operated for sinonasal region schwannoma were identified. The involved sites were nasal dorsum, nasal cavity, pterygopalatine fossa and infratemporal fossa. The mild, non-specific symptoms resulted in patients ignoring their symptoms for a while initially and presenting late. The nasal dorsum lesion was revealed as a surprise during open rhinoplasty for correction of nasal deformity. Complete excision was achieved in all the cases and no recurrence has been noticed during the follow up (varying from 6 months to 6 years) till date. The diverse clinical manifestations and approaches to the treatment of schwannomas in this specific region are discussed. The surgical excision is the standard of care in dealing with these neoplasms. This series highlights the rarity of this pathology in the sinonasal area, diagnostic surprises and the decision making to choose the correct surgical approach for complete excision. Once excised completely, recurrence is not expected.

Maxillary Swing Approach for Central Skull Base Lesions in Extreme Situations: A Single-Institutional Case Series

OBJECTIVE

Radical resection of complex lesions occupying multiple compartments at the central skull base remains a significant challenge, since surgical outcomes may be compromised by insufficient exposure and inappropriate techniques. However, the efficiency of the maxillary swing approach for these lesions has not been sufficiently evaluated. Careful assessment of lesion characteristics must be performed when selecting the appropriate procedure.

METHODS

Between May 2006 and February 2017, 17 patients underwent resection of extensive lesions in the central skull base using the maxillary swing approach. As shown in the representative cases, data regarding clinical findings and technical considerations were reviewed.

RESULTS

Complete resection was achieved in all patients. The pathological findings were diverse, and the majority were schwannomas (9 cases, 52.94%), followed by meningiomas (World Health Organization II) (3 cases, 17.65%). Complications were managed as described in the case illustrations, and symptoms improved with time. The follow-up duration ranged from 62 to 192 months (median, 114 months), while 2 patients were lost to the follow-up. No mortality was observed. Two patients who experienced malignancy relapse were still under observation due to their asymptomatic status.

CONCLUSIONS

Our preliminary results suggest that the maxillary swing approach can be an alternative option for managing extreme cases, such as large, extensive, hypervascularized masses with fibrous or calcified consistency, or for recurrent lesions in the central skull base. En bloc resection can be successfully obtained, resulting in long-term local control.

Transcranial Surgery for Pituitary Tumors: A "Community Neurosurgery Experience"

Background

Despite the evolution of endoscopic techniques, large pituitary adenomas with unfavorable characteristics and irregular anatomical configurations continue to pose a challenge for the dexterity, skills, and patience of endoscopic surgeons. Transcranial surgery retains a significant role in these situations where the tumor access, hemostasis, and dissection around adjoining neurovascular tissues can be controlled efficaciously.

Objective

In this report, we describe our experience with transcranial surgery for pituitary adenomas highlighting its safety and versatility in peripheral centers.

Methods

We accessed the case files and imaging records of pituitary tumors operated between 2001 and 2019 at a private hospital in a major Indian city. The records were analyzed with emphasis on postoperative clinical course, visual, and endocrinological outcomes. The data was analyzed with respect to differences between transcranial and transsphenoidal procedures. Categorical variables were compared with Chi-square test/Fischer's exact test and difference in means evaluated with Welch's t-test.

Results

A total of 178 procedures were performed in 173 patients with pituitary adenoma, who were the subjects of this study. Ninety-eight (56.7%) patients were treated by transsphenoidal excision whereas 80 (46.2%) underwent transcranial procedures (75 primary and five secondary). In the patients operated transcranially, we observed three deaths and nine patients suffered from significant morbidity. Visual outcomes were similar to the group operated transsphenoidally. However, incidence of panhypopituitarism was significantly higher in transcranial procedures; the extent of resection was poorer than transsphenoidal surgeries owing to more extensive nature of tumors.

Conclusions

In low-volume centers, the endoscopic skills required for transsphenoidal resection of large and complex pituitary adenomas may be scarce. Transcranial surgery, dependent on familiar microsurgical techniques and equipment, may still be viable, safe, and an effective option.

Keyhole Endoscopic-Assisted Transcervical Approach to the Upper and Middle Retrostyloid Parapharyngeal Space: An Anatomic Feasibility Study

Objectives The aim of this study was to describe the anatomical nuances, feasibility, limitations, and surgical exposure of the parapharyngeal space (PPS) through a novel minimally invasive keyhole endoscopic-assisted transcervical approach (MIKET).

Design Descriptive cadaveric study.

Setting Microscopic and endoscopic high-quality images were taken comparing the MIKET approach with a conventional combined transmastoid infralabyrinthine transcervical approach.

Participants Five colored latex-injected specimens (10 sides).

Main Outcome Measures Qualitative anatomical descriptions in four surgical stages; quantitative and semiquantitative evaluation of relevant landmarks.

Results A 5 cm long inverted hockey stick incision was designed to access a corridor posterior to the parotid gland after independent mobilization of nuchal and cervical muscles to expose the retrostyloid PPS. The digastric branch of the facial nerve, which runs 16.5 mm over the anteromedial part of the posterior belly of the digastric muscle before piercing the parotid fascia, was used as a landmark to identify the main trunk of the facial nerve. MIKET corridor was superior to the crossing of the accessory nerve over the internal jugular vein within 17.3 mm from the jugular process. Further exposure of the occipital condyle, vertebral artery, and the jugular bulb was achieved.

Conclusion The novel MIKET approach provides in the cadaver straightforward access to the upper and middle retrostyloid PPS through a natural corridor without injuring important neurovascular structures. Our work sets the anatomical nuances and limitations that should guide future clinical studies to prove its efficacy and safety either as a stand-alone procedure or as an adjunct to other approaches, such as the endonasal endoscopic approach.

Middle cranial fossa trigeminal schwannoma resection through endoscopic transnasal maxillary sinus approach: A case report and literature review

The endoscopic transnasal maxillary sinus approach is usually performed in resecting tumors located in the pterygopalatine fossa and infratemporal fossa, but is rarely used in the resection of lesions in the middle cranial fossa. Because of the complicated anatomical structure of the middle cranial fossa, trigeminal schwannomas (TSs) located in this region are usually dissected through conventional craniotomy surgical approaches; however, the endoscopic transnasal maxillary sinus approach can be used in resection of middle cranial fossa TSs. The current study presented the case of a 59-year-old man who suffered intermittent headaches for 2 years without other notable medical history and neurological abnormalities. The patient was diagnosed with a middle cranial fossa TS. After imaging and assessment of anatomical features, the tumor was totally resected through the transnasal maxillary sinus approach. Following surgery, the symptoms were relieved and the patient returned to a normal life. Light numbness was complained of in the distribution area of the maxillary nerve of the right side of the face, but this was gradually relieved. Combined with a literature review, the present case indicated that the endoscopic transnasal maxillary sinus approach may provide a safer and more direct option for resecting middle cranial fossa lesions, which is worthy of increased clinical application.

How I do it: endonasal transcribriform approach for resection of esthesioneuroblastoma

BACKGROUND

Olfactory neuroblastoma, also known as esthesioneuroblastoma, accounts for only 3-6% of sinonasal malignancies but confers a 40% 5-year overall survival.

METHOD

The authors describe techniques for the endonasal, minimally invasive resection of an esthesioneuroblastoma in a 69-year-old man who presented with headaches and anosmia and describe surgical nuances and their effect on adjuvant therapy planning.

CONCLUSION

This approach, along with microsurgical techniques, helped increase tumor visualization, improved marginal resection, and reduced surgical risk, which may improve patient outcomes. Multilayered reconstruction with a synthetic dural substitute and creation of a nasoseptal flap were performed to reduce postoperative cerebrospinal fluid leak.

Characterization of the Saddle Nose Deformity Following Endoscopic Endonasal Skull Base Surgery

Objective: The endoscopic endonasal approach (EEA) is commonly employed in skull base surgery for neoplasm resection. While nasal deformity following EEA is described, this study aimed to perform a detailed qualitative and quantitative assessment of the associated saddle nose deformity (SND) in particular. Setting/Participants: This is a retrospective review of 20 adult patients with SND after endoscopic endonasal approach (EEA) for resection of skull base tumors over a 5-year period at the University of Pittsburgh Medical Center. Outcome Measures: Fifteen measurements related to SND were obtained on pre-and post-operative imaging. Statistical analyses were performed to evaluate differences between pre- and post-operative anatomy. Results: The most common EEA was transsellar. Reconstruction techniques included 9 free mucosal grafts alone, 8 vascularized nasoseptal flaps (NSF), 1 combined free mucosal graft/abdominal fat graft, and 1 combined NSF/fascia lata graft. Imaging analysis showed a trend toward loss of mean nasal height, nasal tip projection and nasolabial angle post-operatively. Sub-group analysis showed that patients with NSF reconstruction had a significantly decreased nasal tip projection (1.2mm, p=0.039) and increased alar base width (1.2mm, p=0.046) post operatively. Patients without functional pituitary microadenomas demonstrated significantly increased nasofrontal angle and decreased nasal tip projection on post-operative imaging, in contrast to those with functional adenomas who had no measurable significant changes. Conclusions: Clinically evident SND does not always lead to significant radiographic changes. This analysis suggests that patients who undergo surgery for indications other than functional pituitary microadenomas or who receive NSF reconstruction develop more marked SND on standard imaging tests.

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Endoscopic Endonasal Approach to the Orbit

Introduction  Although endonasal endoscopic approaches (EEA) to the orbit have been previously reported, a didactic resource for educating neurosurgery and otolaryngology trainees regarding the pertinent anatomy, techniques, and decision-making pearls is lacking. Methods  Six sides of three formalin-fixed, color latex-injected cadaveric specimens were dissected using 4-mm 0- and 30-degree rigid endoscopes, as well as standard endoscopic equipment, and a high-speed surgical drill. The anatomical dissection was documented in stepwise three-dimensional (3D) endoscopic images. Following dissection, representative case applications were reviewed. Results  EEA to the orbit provides excellent access to the medial and inferior orbital regions. Key steps include positioning and preoperative considerations, middle turbinate medialization, uncinate process and ethmoid bulla removal, complete ethmoidectomy, sphenoidotomy, maxillary antrostomy, lamina papyracea resection, orbital apex and optic canal decompression, orbital floor resection, periorbita opening, dissection of the extraconal fat, and final exposure of the orbit contents via the medial-inferior recti corridor. Conclusion  EEA to the orbit is challenging, in particular for trainees unfamiliar with nasal and paranasal sinus anatomy. Operatively oriented neuroanatomy dissections are crucial didactic resources in preparation for practical endonasal applications in the operating room (OR). This approach provides optimal exposure to the inferior and medial orbit to treat a wide variety of pathologies. We describe a comprehensive step-by-step curriculum directed to any audience willing to master this endoscopic skull base approach.

Anatomical Variations and Relationships of the Infratemporal Fossa: Foundation of a Novel Endonasal Approach to the Foramen Ovale

Objective  Access to the infratemporal fossa (ITF) is complicated by its complex neurovascular relationships. In addition, copious bleeding from the pterygoid plexus adds to surgical challenge. This study aims to detail the anatomical relationships among the internal maxillary artery (IMA), pterygoid plexus, V _3, and pterygoid muscles in ITF. Furthermore, it introduces a novel approach that displaces the lateral pterygoid plate (LPP) to access the foramen ovale. Design and Main Outcome Measures  Six cadaveric specimens (12 sides) were dissected using an endonasal approach to the ITF modified by releasing and displacing the LPP and lateral pterygoid muscle (LPTM) as a unit. Subperiosteal elevation of the superior head of LPTM revealed the foramen ovale. The anatomic relationships among the V ₃ , pterygoid muscles, pterygoid plexus, and IMA were surveyed. Results  In 9/12 sides (75%), the proximal IMA ran between the temporalis and the LPTM, whereas in 3/12 sides (25%), the IMA pierced the LPTM. The deep temporal nerve was a consistent landmark to separate the superior and inferior heads of LPTM. An endonasal approach displacing the LPP in combination with a subperiosteal elevation of the superior head of LPTM provided access to the posterior trunk of V ₃ and foramen ovale while sparing injury of the LPTM and exposing the pterygoid plexus. The anterior trunk of V ₃ traveled anterolaterally along the greater wing of sphenoid in all specimens. Conclusion  Displacement of the LPP and LPTM provided direct exposure of foramen ovale and V ₃ avoiding dissection of the muscle and pterygoid plexus; thus, this maneuver may prevent intraoperative bleeding and postoperative trismus.

Anterior and Central Skull Base Tumors: Key Points for the Radiologist to Analyze Prior to Endoscopic Approaches

Initially developed as a minimally invasive technique to approach inflammatory conditions, transnasal endoscopic surgery has progressively expanded its anatomic targets and clinical indications. Consequently, numerous surgical approaches to the anterior and central skull base were developed, referred to as extended endonasal approaches (EEA). The intrinsic advantage of EEA is the exploitation of a natural corridor provided by sinonasal airspaces, with no need for skin incision and osteotomy and limited soft tissue damage. In this context, imaging plays essential role, demonstrating the relevant anatomic relationships of the lesion, the proper surgical corridor, the anatomic variants that may increase the surgical risk.

Comparison of Endoscopic and Microscopic Transsphenoidal Approaches for the Resection of Pituitary Adenoma

Background: The comparative outcomes between endoscopic and microscopic transsphenoidal approaches (ETSA and MTSA) for pituitary adenomas (PAs) remain controversial; however, the numerous literatures have been investigated for decades. This study evaluated the effectiveness of these two techniques using comprehensive measurements and rigorous statistical methods. Methods: A retrospective review of patients who underwent transsphenoidal surgery for PAs at our institution between January 2010 and December 2019 was performed. We included only cases treated by surgeons who have independently performed more than 30 transsphenoidal surgeries. Patients’ characteristics, surgical outcomes, complications, and recurrence were collected for statistical analysis Results: A total of 210 patients, including 138 ETSA patients, and 72 MTSA patients, were analyzed. The baseline characteristics of the two groups were comparable. ETSA patients showed less intraoperative blood loss (191.9 mL vs. 369.9 mL, P < 0.01), a higher rate of gross total resection (GTR) (84.1% vs. 72.2%, P = 0.04), a higher rate of extent of resection (EOR) (95.1% vs. 87.4%, P < 0.01), and shorter hospital stay (10 days vs. 13.5 days, P < 0.01). These better outcomes of ETSA persisted in multivariable regression analysis. Complications were not significantly different between groups. There was no statistical difference between recurrence-free survival of the two groups (P = 0.06, log-rank test) Conclusions: Our study showed that ETSA provided better outcomes and attained similar complications compared to MTSA for the resection of PAs.

The benefits of inferolateral transtubercular route on intradural surgical exposure using the endoscopic endonasal transclival approach

BACKGROUND

Surgical access to the ventral pontomedullary junction (PMJ) can be achieved through various corridors depending on the location and extension of the lesion. The jugular tubercle (JT), a surgically challenging obstacle to access the PMJ, typically needs to be addressed in transcranial exposures. We describe the endoscopic endonasal transclival approach (EETCA) and its inferolateral transtubercular extension to assess the intradural surgical field gained through JT removal. We also complement the dissections with an illustrative case.

METHODS

EETCA was surgically simulated, and the anatomical landmarks were assessed in eight cadaveric heads. Microsurgical dissections were additionally performed along the endoscopic surgical path. Lastly, we present an intraoperative video of the trans-JT approach in a patient with lower clival chordoma.

RESULTS

The EETCA allowed adequate extracranial visualization and removal of the JT. The surgical bony window-obtained along the clivus and centered at the JT via the EETCA-measured 11 × 9 × 7 mm. Removal of the JT provided an improved intradural field within the lower third of the cerebellopontine cistern to expose an area bordered by the cranial nerves VII/VIII and flocculus superior and anterior margin of the lateral recess of the fourth ventricle and cranial nerves IX-XI inferiorly, centered on the foramen of Luschka.

CONCLUSIONS

Removal of the JT via EETCA improves exposure along the lower third of the cerebellopontine and upper cerebellomedullary cisterns. The inferolateral transtubercular extension of the EETCA provides access to the lateral recess of the fourth ventricle, in combination with the ventral midline pontomedullary region.

Impact of Experience on Outcomes After Endoscopic Transsphenoidal Surgery for Acromegaly

OBJECTIVE

Acromegaly is a syndrome of metabolic alterations secondary to increased growth hormone levels from a somatotroph pituitary adenoma. A multidisciplinary approach beginning with surgery, followed by adjuvant radiation or medical therapy for residual disease, is considered standard of care. Several factors affect the likelihood of remission after surgery, but the impact of surgical experience on remission rates has not been adequately assessed.

METHODS

Retrospective review of 203 patients, divided into 2 eras (era 1, 102 patients; era 2, 101 patients) of patients who underwent transsphenoidal surgery for acromegaly by a single surgeon over 11 years, was performed, determining the effect of surgical experience on rates of remission and various complications. Remission was defined according to the 2014 Endocrine Society Clinical Practice Guideline.

RESULTS

The rate of surgical remission was 40.6% (62.9% among noninvasive adenomas). Rates of surgical remission significantly improved in the latter half of this cohort (31.2% in the first half vs. 50% in the second half), despite other factors being comparable. On multivariate analysis, surgeon experience, cavernous sinus invasion, and preoperative growth hormone levels affected the rates of surgical remission. Rates of cerebrospinal fluid leak and hypopituitarism were lower in the second half, whereas resolution of acromegaly-associated comorbidities was increased.

CONCLUSIONS

We report, in this large single-surgeon review of endoscopically operated acromegaly cases, increased rates of surgical remission and reduced complications with increasing surgeon experience. The overall experience of the treating team in dealing with perioperative and intraoperative factors also contributes to improved outcomes.

The Application of Three-Dimensional Technology Combined With Image Navigation in Nasal Skull Base Surgery

Three-dimensional (3D) technology including 3D reconstruction and 3D printing technology, has been widely used in clinical treatment, especially in surgical planning, and image navigation technology, which can make surgical procedures more accurate, now is also increasingly favored by surgeons. But the combination of those 2 technologies was rarely reported. Thus, this study will preliminarily investigate the feasibility and the effect of the combination of 2 technologies in endonasal skull base surgery. Eight patients were involved in this study (from October 2016 to July 2017 at The Affiliated Hospital of Qingdao University), 5 cases of nasal skull base tumors and 3 cases of foreign body perforation. All operations were done under the assistance of 3D technology and image guidance system. Surgical discussion with patient, preoperative planning and clinical teaching were investigated between 2D images and 3D models by voting. For all cases, 3D reconstruction model and 3D printed model were deemed to be more helpful than CT/MRI images in surgical discussion with the patient; surgical simulation on 3D model in preoperative planning was largely deemed to be helpful and very helpful; and in clinical teaching, 3D models combined with image guidance system were deemed to be more helpful in understanding the disease than using 2D images. Besides, all patients recovered well after surgery, no recurrence and complications were found in the follow-up. The combination of 3D technology and electromagnetic image guidance system could improve surgical efficiency and the quality of clinical teaching.

Modern endoscopic skull base neurosurgery

INTRODUCTION

Since the early use of the endoscopic view for treating simple intrasellar pituitary adenomas, the skull base surgery has experienced an unprecedented revolution elevating the treatment of skull base lesions to the next level in proficiency and excellence of care.

METHODS

We have reviewed the preclinical and clinical evidence supporting the use of the endoscope in the treatment of skull base lesions. In this article, we aim to discuss and provide a wide view of the current indications and future perspectives of the endoscopic endonasal approaches (EEA) and of the endoscopic transcranial approaches.

RESULTS

As in the development of any other technique, EEA have gone through a transformation process from theoretical anatomic models to a pragmatic clinical use. Along the way, EEA have required several modifications, as well as pushbacks in the application of this technique in some indications. This process has resulted in the provision of an additional tool to the current surgical armamentarium that allows the skull base surgeon to face most challenging lesions along the skull base.

CONCLUSIONS

The judicious combination of transcranial and endoscopic-transnasal approaches warrants highest chances of achieving satisfactory tumors resection with a reduced risk of complications.

Transorbital endoscopic approaches to the skull base: a systematic literature review and anatomical description

Transorbital endoscopic approaches are increasing in popularity as they provide corridors to reach various areas of the ventral skull base through the orbit. They can be used either alone or in combination with different approaches when dealing with the pathologies of the skull base. The objective of the current study is to evaluate the surgical anatomy of transorbital endoscopic approaches by cadaver dissections as well as providing objective clinical data on their actual employment and morbidity through a systematic review of the current literature. Four cadaveric specimens were dissected, and step-by-step dissection of each endoscopic transorbital approach was performed to identify the main anatomic landmarks and corridors. A systematic review with pooled analysis of the current literature from January 2000 to April 2020 was performed and the related studies were analyzed. Main anatomical landmarks are presented based on the anatomical study and systematic review of the literature. With emphasis on the specific transorbital approach used, indications, surgical technique, and complications are reviewed through the systematic review of 42 studies (19 in vivo and 23 anatomical dissections) including 193 patients. In conclusion, transorbital endoscopic approaches are promising and appear as feasible techniques for the surgical treatment of skull base lesions. Surgical anatomy of transorbital endoscopic approaches can be mastered through knowledge of a number of anatomical landmarks. Based on data available in the literature, transorbital endoscopic approaches represent an important complementary that should be included in the armamentarium of a skull base team.

Therapeutic approach to non-functioning pituitary adenomas

The treatment of non-functioning pituitary adenomas raises two questions: when should they be treated and what role does each available treatment play. We review the usefulness of the different treatments and propose a therapeutic scheme based on the existing literature. Active treatment of pituitary adenomas should be performed when they produce symptoms, have contact with the optic tract, or have grown on imaging tests. The treatment is surgical, using radiotherapy for cases with significant non-removable postsurgical tumour remnants and for those in which histopathology studies show aggressive features. Medical treatment is reserved for situations in which surgical and radiotherapy treatments have been exhausted. The most advisable surgical treatment is endoscopic, although experienced neurosurgeons achieve results with microsurgery that are only slightly inferior.

Early practices in endonasal skull base surgery during the COVID-19 pandemic: a global survey

OBJECTIVE

During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, endoscopic endonasal surgery (EES) is feared to be a high-risk procedure for the transmission of coronavirus disease 2019 (COVID-19). Nonetheless, data are lacking regarding the management of EES during the pandemic. The object of this study was to understand current worldwide practices pertaining to EES for skull base/pituitary tumors during the SARS-CoV-2 pandemic and provide a basis for the formulation of guidelines.

METHODS

The authors conducted a web-based survey of skull base surgeons worldwide. Different practices by geographic region and COVID-19 prevalence were analyzed.

RESULTS

One hundred thirty-five unique responses were collected. Regarding the use of personal protective equipment (PPE), North America reported using more powered air-purifying respirators (PAPRs), and Asia and Europe reported using more standard precautions. North America and Europe resorted more to reverse transcriptase-polymerase chain reaction (RT-PCR) for screening asymptomatic patients. High-prevalence countries showed a higher use of PAPRs. The medium-prevalence group reported lower RT-PCR testing for symptomatic cases, and the high-prevalence group used it significantly more in asymptomatic cases.Nineteen respondents reported transmission of COVID-19 to healthcare personnel during EES, with a higher rate of transmission among countries classified as having a medium prevalence of COVID-19. These specific respondents (medium prevalence) also reported a lower use of airborne PPE. In the cases of healthcare transmission, the patient was reportedly asymptomatic 32% of the time.

CONCLUSIONS

This survey gives an overview of EES practices during the SARS-CoV-2 pandemic. Intensified preoperative screening, even in asymptomatic patients, RT-PCR for all symptomatic cases, and an increased use of airborne PPE is associated with decreased reports of COVID-19 transmission during EES.

Infratemporal fossa surgical approaches to primary/recurrent malignancies of salivary origin: paradigm surgical shift, patient selection, and oncologic outcomes

PURPOSE OF REVIEW

To review, the surgical approaches available on diagnosing a patient with salivary gland malignancy in the infratemporal fossa (ITF). To comment on patient evaluation and method of treatment selection. To identify and report on patient outcome data and make recommendations on future needs.

RECENT FINDINGS

There is a need to define the anatomic boundaries contents of the ITF, masticator space, parapharyngeal space (PPS), pterygopalatine fossa, ventral skull base, and paramedian skull base, as evidence from publications. The pathological subtypes identified mainly include adenoid cystic and mucoepidermoid carcinomas. The source of these tumours originates from primary disease in the sinonasal tract and nasopharynx superiorly, and the PPS/deep lobe of parotid inferiorly. Current surgical options available, in suitable selected patient, available in tertiary head and neck cancer hospitals, which have available facilities and staffing is the endoscopic endonasal approach. This approach offers patients a 'complete margin-free surgical excision', minimal complications, shorter hospital stay, and no delay with commencement of any adjuvant treatment compared with the traditional 'open transcutaneous' approach.

SUMMARY

The current evidence specifically to the surgical management of salivary gland malignancy involving the ITF is sparse, with great difficult identifying treated patients and their details among a heterogeneous group of patients with many lesions. There is a need for patient data that have specific pathologic conditions to be amalgamated from such centers and publish on outcome events.

Outcomes of Endoscopic Versus Open Skull Base Surgery in Pediatric Patients

OBJECTIVE/HYPOTHESIS

To characterize the pathology and outcomes of skull base surgery in the pediatric population by open versus endoscopic surgical approach.

STUDY DESIGN

Retrospective cohort study.

METHODS

A retrospective review of pediatric patients (<18 years) who underwent skull base surgery for nonmalignant disease from May 2000 to August 2019 was performed. Patient demographics, pathology, and operative characteristics by surgical approach were recorded and analyzed. Patients with a combined endoscopic/open approach were classified as open for the analysis.

RESULTS

Eighty-two pediatric skull base patients were identified with a mean age of 11.3 years (standard deviation 5.2). A purely endoscopic approach was used in 63 (77%) patients, a purely open approach was used in nine (11%) patients, and a combined open/endoscopic approach was used in 10 (12%) patients. The all-cause complication rate was 9.8%. There was no statistically significant difference in rate of complications between patients with an open versus endoscopic approach for resection (15.8% vs. 7.9%; P = .379). Risk of having a complication did not significantly vary by patient age. The odds of having a complication with an open approach was not statistically significant in a multivariable model adjusted for age, sex, race, intraoperative cerebrospinal fluid leak, tracheostomy requirement, and vascular flap use (odds ratio 2.76, 95% confidence interval 0.28-26.94; P = .383).

CONCLUSIONS

Our retrospective study demonstrates a similar risk of complication for open versus endoscopic approach to resection in pediatric skull base patients at our institution. Safety and feasibility of the endoscopic approach has previously been demonstrated in children, and this is the first study to directly compare outcomes with open approaches.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:996-1001, 2021.

Surgical implementation and efficacy of endoscopic endonasal extradural posterior clinoidectomy

OBJECTIVE

The endoscopic endonasal approach (EEA) for skull base tumors has become an important topic in recent years, but its use, merits, and demerits are still being debated. Herein, the authors describe the nuances and efficacy of the endoscopic endonasal extradural posterior clinoidectomy for maximal tumor exposure.

METHODS

The surgical technique included extradural posterior clinoidectomy following lateral retraction of the paraclival internal carotid artery and extradural pituitary transposition. In cases with prominent posterior clinoid process, a midline sellar dura cut was added to facilitate extradural exposure. Forty-four consecutive patients, in whom this technique was performed between 2016 and 2018 at Osaka City University Hospital, were reviewed. The pathology included 19 craniopharyngiomas, 7 chordomas, 6 meningiomas, 6 pituitary adenomas, 4 chondrosarcomas, and 2 miscellaneous. Utilization and effectiveness of this approach were further demonstrated with neuroimaging.

RESULTS

Extradural posterior clinoidectomies were successfully applied in all patients without permanent neurovascular injury and with better maneuverability and greater resection rate of the tumors. Four patients experienced transient postoperative abducens nerve paresis, and 1 patient experienced transient postoperative oculomotor nerve paresis; however, the patients with deficits recovered within 3 months. On radiological examination, the surgical field was 2.2 times wider in cases with bilateral posterior clinoidectomy than in cases without posterior clinoidectomy.

CONCLUSIONS

The extended EEA with extradural posterior clinoidectomy creates an extra working space and allows adequate accessibility with safe surgical maneuverability to remove tumors that extend behind the posterior clinoid and dorsum sellae.

TRANS-FRONTAL SINUS APPROACH FOR OLFACTORY GROOVE MENINGIOMAS: A 19 YEAR EXPERIENCE

INTRODUCTION

Olfactory groove meningiomas (OGMs) account for 8-13 % of all intracranial meningiomas. The gold standard of treatment is generally surgery, however various approaches have been used and the literature is still uncertain about the superiority of one treatment over the others. The most debated techniques are traditional microscopic open approaches versus the endoscopic endonasal ones. The aim of this paper is to prove a valid surgical route that gathers the benefits of both endoscopic and transcranial routes.

METHODS

Fifty consecutive patients underwent trans-frontal sinus surgical removal of an OGM between January 2000 and January 2019 at the Neurosurgical Departments in Torino, Brescia and Legnano (Italy). The clinical features were collected in a database and compared with neuroimaging and outcomes. All patients were investigated with neuroimaging techniques. Clinical evaluations were performed 3-4 months and 1 year after surgery, together with neuroradiological follow-up.

RESULTS

All patients with OGM underwent Simpson grade I resection. The most common neurological symptom leading to neuroradiological evaluations were headaches (36 %), followed by behavioural changes (30 %), hyposmia/anosmia (12 %), visual impairments (6%) and focal deficits (6%). At 3-4 months follow-up 48 patients underwent a brain MRI (2 patients underwent a brain CT), and a complete resection was confirmed in 45 patients (94 %).

CONCLUSIONS

Despite different techniques and studies supported by good evidence, there is no consensus on the best surgical approach for OGMs. The data shown in this article suggests that the trans-frontal sinus approach is a valid alternative to an endoscopic approach and the classical transcranial routes, collecting benefits from both approaches.

Role of craniofacial surgery in oral and maxillofacial tumors involving the skull base: A retrospective analysis of 126 patients

OBJECTIVES

Oral and maxillofacial tumors involving the skull base (SB) are rare and complex, making treatment difficult and controversial. The purpose of the present study was to evaluate the treatment efficacy of craniofacial surgery (CFS).

STUDY DESIGN

Patients who underwent CFS for these tumors between May 2000 and November 2017 were retrospectively analyzed. Clinicopathologic and treatment modality data were collected and follow-up was recorded. Kaplan-Meier and log-rank tests and Cox-regression model were used for survival analysis.

RESULTS

In total, 126 patients were enrolled (70 males and 56 females; 97 malignant tumors). Squamous cell carcinoma accounted for the majority of tumors. The lip-submandibular-neck approach was most frequently applied. Through-and-through SB bone or partial dura resection was performed in 42 cases. A pathologic positive margin was found in 18 cases. Of the included patients, 80 underwent simultaneous craniofacial reconstruction. The postoperative complications rate was 11.1%. Estimated 1-year, 3-year, and 5-year overall survival rates were 78.8%, 68.2%, and 54.4% respectively; and the 1-year, 3-year, and 5-year recurrence-free survival rates were 77.4%, 66.8%, and 63.8%, respectively. Multivariate analysis indicated postoperative complications, radiotherapy, recurrence, and metastasis status had a negative impact on survival (P < .05).

CONCLUSIONS

Although tumors involving the SB had various clinicopathologic characteristics, with interdisciplinary cooperation, CFS is an optimal option.

Hybrid antero-lateral transcondylar approach to the clivus: a laboratory investigation and case illustration

BACKGROUND

Surgical treatment of lesions involving the ventral craniovertebral junction (CVJ) and the lower clivus, traditionally involved complex lateral or transoral approaches to the skull base. However, mid or upper clivus involvement requires more extensive lateral approaches. Recently, the endoscopic endonasal approach (EEA) has become the standard for upper CVJ lesions and medial clival, and a valuable alternative for those tumors extending in its upper third as well as laterally. However, the EEA is associated with an increased risk of post-operative CSF leakage and infection when the tumor is characterized by an intradural extension. Furthermore, whenever the tumor has significant lateral and/or inferior extension below the odontoid process, the chances for a complete resection decrease.

METHOD

To analyze the extent of exposure of a hybrid microscopic-endoscopic transcondylar antero-lateral approach to the CVJ and clival region, and to verify its effectiveness in terms of mid and upper clival access. Five silicone-injected cadaver heads were used. Following a standard antero-lateral approach, condylectomy and jugular tubercle drilling were performed, after which angled endoscopes were utilized to extend the bone resection to the clivus. A volumetric assessment of the amount of clival removal was carried out. A case of CVJ chordoma operated through this approach is presented.

RESULTS

The hybrid antero-lateral transcondylar approach provides adequate exposure of the ventral CVJ, up to the dorsum sellae and the sphenoid sinus, the contralateral petrous apex, and the contralateral paraclival internal carotid artery (ICA). Approximately 60% of the total clival volume can be removed with this approach. The main limitation is the limited visualization of the ipsilateral paraclival ICA and petrous apex.

CONCLUSION

The hybrid antero-lateral transcondylar approach is a valuable surgical option for CVJ tumor extending from C2 to the mid and upper clivus.

Visual Outcomes After Endoscopic Endonasal Resection of Orbital Lesions

BACKGROUND

The endoscopic endonasal approach (EEA) has been increasing in popularity as an alternative to traditional transcranial and transorbital approaches in the treatment of orbital pathological entities. The purpose of the present study was to examine the outcomes of patients who had undergone EEA resection of orbital lesions at our center.

METHODS

We performed a retrospective medical record review of patients who had undergone the EEA for resection of orbital lesions and orbital apex decompression from January 1, 2006 to December 1, 2019. For all the patients, the demographic data, presenting symptoms, symptom duration, imaging data, operative details, and postoperative outcomes were collected and reviewed.

RESULTS

Nine patients underwent endoscopic endonasal resection of orbital lesions and orbital apex decompression at our center, including 6 male patients and 3 female patients. The mean age was 49.4 years, and the mean follow-up period was 3.8 years (range, 1-13.5 years). The orbital pathological lesions that were treated included nasopharyngeal carcinoma, hemangioma, fibrous dysplasia, IgG4 pseudotumor, inverted papilloma, angioleiomyoma, adenocarcinoma, and neuroendocrine paraganglioma metastasis. All the patients presented with exophthalmos of the affected orbit. Of the 9 patients, 5 presented with decreased visual acuity on examination. Postoperatively, 1 of these 5 patients had improved to baseline visual acuity, 3 had stable vision, and 1 had brief improvement before experiencing progressive visual decline 1 month postoperatively. Two patients presented with diplopia, and both improved postoperatively. Three patients experienced new, transient, and self-limiting postoperative diplopia.

CONCLUSIONS

For patients with orbital lesions causing compressive optic neuropathy, the endoscopic endonasal approach can be used as an alternative strategy in appropriately selected patients.