Anterolateral keyhole transorbital routes to the skull base: a comparative anatomical study.

OBJECTIVE: Although keyhole transorbital approaches are gaining traction, their indications have not been adequately studied comparatively. In this study the authors have defined them also as transwing approaches-meaning that they use the different facies of the sphenoid wing for cranial entry-and sought to compare the four major ones: 1) lateral orbitocraniotomy through a lateral canthal incision (LatOrb); 2) modified orbitozygomatic approach through a palpebral incision (ModOzPalp); 3) modified orbitozygomatic approach through an eyebrow incision (ModOzEyB); and 4) supraorbital craniotomy through an eyebrow incision (SupraOrb), coupled with its expanded version (SupraTransOrb). METHODS: Cadaveric dissections were performed at the neuroanatomy lab. To delineate the skull base exposure, four formalin-fixed heads were used, with two sides dedicated to each approach. The outer limits were assessed via image guidance and were mapped and illustrated accordingly. A fifth head was dissected purely endoscopically, just to facilitate an overview of the transwing concept. Qualitative features were also rigorously examined. RESULTS: The LatOrb proves to be more versatile in the middle cranial fossa (MCF), whereas the anterior cranial fossa (ACF) exposure is limited to a small area above the sphenoid ridge. An anterior clinoidectomy is possible; however, the exposure of the roof of the optic canal is suboptimal. The ModOzPalp adequately exposes both the ACF and MCF. Its lateral trajectory allows the inferior to superior view, yet there is restricted access to the medial anterior skull base (olfactory groove). The ModOzEyB also provides extensive exposure of the ACF and MCF, but has a more superior to inferior trajectory compared to the ModOzPalp, making it more appropriate for pathology reaching the medial anterior skull base or even the contralateral side. The anterior clinoidectomy is performed with improved visualization of the optic canal. The SupraOrb provides mainly anterior cranial base exposure, with minimal middle fossa. An anterior clinoidectomy can be performed, but without any direct observation of the superior orbital fissure. Some MCF access can be accomplished if the lateral sphenoid wing is drilled inferiorly, leading to its highly versatile variant, the SupraTransOrb. CONCLUSIONS: All the aforementioned approaches use the sphenoid wing as skull base corridor from a specific orientation point; hence these are designated as transwing approaches. Their peculiarities mandate careful case selection for the effective and safe completion of the surgical goals.

The utility of inflammatory biomarkers in predicting overall survival and recurrence in skull base chordoma.

OBJECTIVE: Numerous studies have investigated the impact of inflammatory factors in cancer, yet few attempts have been made to investigate these markers in skull base chordoma (SBC). Inflammatory values including neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), lymphocyte-monocyte ratio (LMR), systemic immune inflammation index (SII), and systemic inflammation response index (SIRI) can serve as prognostic markers in various cancers. This study aimed to determine whether these inflammatory factors influence overall survival (OS) or progression-free survival (PFS) in patients with primary SBC. METHODS: The electronic medical records of patients with primary SBC who underwent resection from 2001 to 2020 were retrospectively reviewed for the associations of sex, age at diagnosis, preoperative steroid use, tumor volume, extent of resection, adjuvant radiation after surgery, tumor metastasis, Ki-67 index, percent homozygous deletion of 9p23 and percent 1p36 loss, and potential prognostic inflammatory markers of NLR, PLR, LMR, SII, and SIRI with the primary outcome measures of OS and PFS. Maximum log-rank statistical tests were used to determine inflammatory marker thresholds for grouping prior to Kaplan-Meier and Cox proportional hazards analysis for OS and PFS of the elucidated groups. RESULTS: The cohort included 115 primary SBC patients. The mean ± SD tumor volume was 23.0 ± 28.0 cm3, 73% of patients received gross-total resection, 40% received postoperative radiation, 25% had local recurrence, and 6% had subsequent metastatic disease (mean follow-up 47.2 months). Univariable Cox analysis revealed that NLR (p < 0.01), PLR (p = 0.04), LMR (p = 0.04), SII (p < 0.01), and SIRI (p < 0.01) were independently associated with PFS. Additionally, NLR (p = 0.05) and SII (p = 0.03) were significant in multivariable Cox analysis of PFS. However, both univariable and multivariable Cox analysis revealed no correlations with OS. CONCLUSIONS: The routine assessment of inflammatory biomarkers such as NLR and SIRI could have prognostic value in postresection SBC patients.

The role of endoscopic endonasal surgery in the management of prolactinomas based on their invasiveness into the cavernous sinus.

PURPOSE: To review our institutional experience with the surgical management of prolactinomas through the endoscopic endonasal approach with specific focus on cavernous sinus invasion. METHODS: Clinical and radiographic data were collected retrospectively from the electronic medical record of 78 consecutive patients with prolactinomas undergoing endoscopic endonasal resection from 2002 to 2019. Immediate and late post-operative remission were defined as prolactin < 20 ng/mL within 14 days and 1-year of surgery without adjuvant therapy, respectively. Cavernous sinus invasion was quantified by Knosp score. RESULTS: A total of 78 patients with prolactinoma, 59% being male, underwent surgical resection with a mean age of 37 ± 13 years. Indications for surgery were medication resistance in 38 patients (48.7%), medication intolerance in 11 (14.1%), and patient preference in 29 (37.2%). Patients with Knosp 0-2 achieved higher immediate remission rates (83.8%) compared to patients with Knosp 3 (58.8%) and Knosp 4 (41.7%) patients (p = 0.003). Long-term remission rates were 48.7% and increased to 71.8% when combined with adjuvant treatments. Knosp 4 prolactinomas had significantly higher tumor volumes, higher preoperative prolactin levels, higher recurrence rates, higher rates of adjuvant therapy utilization, and were more likely to have failed dopamine agonist therapy compared to other tumor grades (p < 0.05). We encountered 18 complications in our series, and no cerebrospinal fluid leaks. CONCLUSION: The endoscopic endonasal approach is a safe and effective modality that can be employed in properly selected patients with invasive prolactinomas. It is associated with improved control and remission rates despite cavernous sinus invasion, though at a lower rate than without invasion.

Applications of Endoscopic Endonasal Surgery in Early Childhood: A Case Series.

INTRODUCTION: Endoscopic endonasal surgery (EES) has been slower to gain popularity in early childhood due to anatomical challenges. We sought to describe the safety and efficacy of EES in early childhood. METHODS: All patients younger than 7 years who underwent EES at a large Cranial Base Center from 2002 to 2019 were reviewed as a retrospective cohort study. RESULTS: Thirty-six patients underwent EES before the age of 7 years. Four patients had two-stage EES. Two patients required combined transcranial and endonasal approaches. The mean age at the time of initial surgery was 4 years (range: 1-6). Twenty patients were male, and 16 were female. Of 21 tumors intended for resection, 11 patients had gross total resections, and 10 had near total (>95% tumor removed) resections. Nine patients (43%) had recurrences, of which 6 were craniopharyngiomas (p = 0.01). There was no difference in recurrence rates based on the degree of resection (p = 0.67). Three cerebrospinal fluid (CSF) leaks occurred following primary EES (8%). Following an increase in nasoseptal flap usage (31-52%) and CSF diversion (15-39%) in 2008, there was only one CSF leak out of 23 patients (4 vs. 15%; p = 0.54). Postoperatively, 1 patient developed a permanent new cranial neuropathy, and 1 patient developed a permanent visual field cut. Six patients developed permanent postoperative panhypopituitarism, of which all were craniopharyngiomas (p < 0.001). The mean follow-up was 64 months. CONCLUSIONS: Early childhood EES is both safe and technically feasible for a variety of pathologies.

Reconstruction after endoscopic surgery for skull base malignancies.

INTRODUCTION: The ability to resect malignancies of the ventral skull base using endoscopic endonasal approaches has created a need for effective endoscopic reconstructive techniques. The purpose of this review is to summarize current techniques for reconstruction of large skull base defects during endoscopic endonasal surgery. METHODS: Recent medical literature was reviewed to identify techniques and best practices for repair of skull base defects during endoscopic endonasal surgery. Preference was given to evidence-based recommendations. RESULTS: Superior results are observed with multilayer inlay/onlay grafts supplemented with vascularized flaps. The nasoseptal flap is the primary reconstructive flap for most defects; secondary choices include the lateral nasal wall flap and extracranial pericranial flap. Clival defects are particularly challenging and are further augmented with adipose tissue to prevent pontine herniation. Perioperative management including the use of lumbar cerebrospinal fluid drainage minimizes the risk of a postoperative leak in high-risk patients. Postoperative cerebrospinal fluid leaks are managed similarly to primary leaks and may require use of a secondary vascularized flap. Complications of reconstructive flaps include flap necrosis and cosmetic nasal deformity. CONCLUSION: Large defects of the anterior, middle, and posterior cranial fossae can be managed similarly by adhering to basic principles of reconstruction. Future developments will improve stratification of patients into reconstructive groups and allow tailored reconstructive algorithms. New biomaterials may replace autologous tissue and facilitate endoscopic repair. Improved monitoring will allow for assessment of the reconstructive site with early detection and repair of postoperative cerebrospinal fluid leaks.

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.

The Relationship of Paranasal Sinus Opacification to Hospital-Acquired Pneumonia in the Neurologic Intensive Care Unit Patient.

BACKGROUND: The association between intensive care unit (ICU) sinusitis and the development of lower airway infections remains unclear. The objective of this study was to determine the correlation between the development of radiographic sinus opacification and pneumonia in the neurologic ICU setting. METHODS: A retrospective review of head computed tomography or magnetic resonance imaging of 612 patients admitted to the neurocritical care unit at a tertiary care center from April 2013 through April 2014 was performed. Paranasal sinus opacification was measured using Lund-Mackay scores (LMS). A diagnosis of pneumonia was determined by the ICU team from radiographic, laboratory, and pulmonary data. Exclusion criteria included a history of endonasal surgery, sinonasal malignancy, facial fractures, ICU admission less than 3 days, or inadequate imaging. RESULTS: Worsening sinus opacification occurred in 42.6% of patients and pneumonia in 18.5% of patients during ICU admission. Of the patients who developed pneumonia, 71.7% also developed worsening sinus opacification (P < .001). In 80.2% of cases, the sinus opacification developed prior to the diagnosis of pneumonia. The mean highest LMS for patients who developed pneumonia was 4.24 compared to 1.99 in patients who did not develop pneumonia (P < .001). Sinus air-fluid levels or complete sinus opacification occurred in a larger proportion of patients who developed pneumonia (46.9% vs 19.4%, P < .001). Mortality rates for patients with no pneumonia or sinusitis, pneumonia only, sinusitis only, and sinusitis with pneumonia were 7.6%, 15.6%, 18.3%, and 25.9%, respectively (P < .001). CONCLUSIONS: This study finds a strong relationship between worsening sinus opacification in the neurologic ICU patient to the development of hospital-acquired pneumonia and increased mortality.

Staged Reconstruction (Delayed-Immediate) of the Maxillectomy Defect Using CAD/CAM Technology.

BACKGROUND: Computer-aided design/computer-aided manufacturing (CAD/CAM) technology has become increasingly popular for free fibula reconstruction of the mandible. The same technology, however, has not been widely utilized in immediate complex midface reconstruction utilizing free fibula flaps. Maxillary defects are difficult to precisely predict or produce matched cutting guides for after the ablative surgery. We present a protocol for "delayed-immediate" two-stage reconstruction for complex mid-facial defects, by delaying lymph node neck dissection and using CAD/CAM technology for delayed bony reconstruction. METHODS: Stage 1 includes the extirpative surgery, placement of a temporary obturator, and an immediate post-excision fine cut computed tomography (CT) of the defect that is used for CAD/CAM planning. The time interval between stages is used for virtual surgical planning (VSP) and provides an opportunity for the final pathologic margins to be evaluated. At stage 2, definitive reconstruction is performed in conjunction with the delayed neck dissection. Briefly delaying the neck dissection until stage 2 allows for recipient vessel dissection and microsurgical anastomoses to safely occur in a surgically naïve neck. CONCLUSION: A two-stage delayed-immediate reconstruction of complex mid-face defects can be safely and effectively performed. This protocol takes advantage of advancing CAD/CAM technology, provides an opportunity to evaluate final margins, and avoids recipient vessel dissection and microsurgery in previously operated or irradiated necks.

Endoscopic transnasal skull base surgery: pushing the boundaries.

The endoscopic endonasal approach (EEA) has significantly evolved since its initial uses in pituitary and sinonasal surgery. The literature is filled with reports and case series demonstrating efficacy and advantages for the entire ventral skull base. With competence in 'minimally invasive' parasellar approaches, larger and more complex approaches were developed to utilize the endonasal corridor to create maximally invasive endoscopic skull base procedures. The challenges of these more complex endoscopic procedures include a long learning curve and navigating in a narrow corridor; reconstruction of defects presented new challenges and early experience revealed a significantly higher risk of cerebrospinal fluid leak. Despite these challenges, there are many benefits to the EEA including avoidance of brain and neurovascular retraction, improved visualization, a direct corridor onto many tumors and the two-surgeon approach. Most importantly, the EEA provides a midline corridor to directly access tumors, which displace critical neurovascular structures laterally, giving it an inherent advantage of minimizing any manipulation of these structures and thus decreasing their potential injury.

Intraoperative Image Guidance Improves Outcomes in Complex Orbital Reconstruction by Novice Surgeons.

PURPOSE: This study aims to describe the utility of surgical navigation in improving operative outcomes in complex orbital reconstruction by novice compared with experienced surgical trainees. MATERIALS AND METHODS: A randomized, controlled cadaveric study was conducted at the University of Pittsburgh School of Medicine with otolaryngology and ophthalmology residents and fellows. Participants were divided into novice (postgraduate year 2-4 residents) and experienced (postgraduate year 5 residents and fellows) groups. Ten cadaveric specimens with pre-dissection computed tomography images underwent endoscopic resection of the orbital floor and lamina papyracea bilaterally. Participants performed reconstruction with or without the use of surgical navigation, randomized by laterality and order of the use of navigation. Post-dissection imaging was obtained after reconstruction and compared with pre-dissection imaging. The primary outcome was orbital volume; secondary outcomes included the participant's operative time and National Aeronautics and Space Administration Task Load Index score, a subjective workload assessment measure. Matched-pair t tests and 2-way analysis of variance were used for statistical analysis. RESULTS: Novice participants (n = 6) had improved outcomes with respect to orbital volume when using surgical navigation compared with experienced participants (n = 4). There were no differences in operative times or National Aeronautics and Space Administration Task Load Index scores when using surgical navigation. CONCLUSIONS: In a cadaveric setting, use of surgical navigation by novice surgeons improves post-dissection orbital volume in complex orbital reconstruction. Surgical navigation should be considered as an adjunct to surgical training and simulation curricula.

Clinical Considerations for Vascularized Composite Allotransplantation of the Eye.

Vascularized composite allotransplantation represents a potential shift in approaches to reconstruction of complex defects resulting from congenital differences as well as trauma and other acquired pathology. Given the highly specialized function of the eye and its unique anatomical components, vascularized composite allotransplantation of the eye is an appealing method for restoration, replacement, and reconstruction of the nonfunctioning eye. Herein, we describe conventional treatments for eye restoration and their shortcomings as well as recent research and events that have brought eye transplantation closer to a potential clinical reality. In this article, we outline some potential considerations in patient selection, donor facial tissue procurement, eye tissue implantation, surgical procedure, and potential for functional outcomes.

Endoscopic endonasal surgery for olfactory groove meningiomas: outcomes and limitations in 50 patients.

OBJECT: Recently, endoscopic endonasal surgery (EES) has been introduced in the management of skull base tumors, with constantly improving outcomes and increasing indications. The authors retrospectively reviewed the effectiveness of EES in the management of olfactory groove meningiomas. METHODS: Between February 2003 and December 2012, 50 patients (64% female) with olfactory groove meningiomas underwent EES at the University of Pittsburgh Medical Center. The authors present the results of EES and analyze the resection rates, clinical outcome, complications, and limitations of this approach. RESULTS: Forty-four patients presented with primary tumors, whereas six were previously treated elsewhere. The patients' mean age was 57.1 years (range 27-88 years). Clinical presentation included altered mental status (36%), visual loss (30%), headache (24%), and seizures (20%). The mean maximum tumor diameter was 41.6 mm (range 18-80 mm). All patients underwent EES, which was performed in stages in 18 giant tumors. Complete tumor resection (Simpson Grade I) was achieved in 66.7% of the 45 patients in whom it was the goal, and 13 (28.9%) had neartotal resection (> 95% of the tumor). Tumor size, calcification, and absence of cortical cuff from vasculature were significant factors that influenced the degree of resection (p = 0.002, p = 0.024, and p = 0.028, respectively). Tumor residual was usually at the most lateral and anterior tumor margins. Following EES, mental status was improved or normalized in 77.8% of the cases, vision was improved or restored in 86.7%, and headaches resolved in 83.3%. There was no postoperative deterioration of presenting symptoms. Complications were increased in tumors > 40 mm and included CSF leakage (30%), which was significantly associated with lobular tumor configuration (p = 0.048); pulmonary embolism/deep vein thrombosis, more commonly in elderly patients (20%); sinus infections (10%); and delayed abscess months or years after EES (6%). One patient had an intraoperative vascular injury resulting in transient hemiparesis (2%). There were no perioperative deaths. During a mean follow-up period of 32 months (median 22 months, range 1-115 months), 1 patient underwent repeat EES for tumor regrowth. CONCLUSIONS: Endoscopic endonasal surgery has shown good clinical outcomes regardless of patient age, previous treatment, or tumor characteristics. Tumor size > 40 mm, calcification, and absence of cortical vascular cuff limit GTR with EES; in addition, large tumors are associated with increased postoperative complications. Significant lateral and anterior dural involvement may represent indications for using traditional craniotomies for the management of these tumors. Postoperative CSF leakage remains a problem that necessitates innovations in EES reconstruction techniques.

Endoscopic Endonasal Far-Medial Approach: 2-Dimensional Operative Video.

INDICATIONS CORRIDOR AND LIMITS OF EXPOSURE: Endoscopic endonasal far-medial approach provides an effective and safe corridor to access the parasagittal structures of the lower clivus such as the medial jugular tubercle (JT) and occipital condyle (OC) for lesions that displace neurovascular structures laterally. ANATOMIC ESSENTIALS NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT: Parapharyngeal internal carotid arteries (ICAs) run posterolateral to the eustachian tubes and lateral to the OC. The supracondylar groove is a superficial landmark for the hypoglossal canal, which divides the lateral extension of clivus into the JT and OC. ESSENTIAL STEPS OF THE PROCEDURE: Typically, approach starts with opening of the sphenoid sinus to localize the paraclival ICA. An "inverted U" rhinopharyngeal (RP) flap exposing the supracondylar groove and lower clivus. Doppler and navigation can confirm the course of the ICA. Drilling is started in the midline in the lower clivus and extended laterally to expose the hypoglossal canal, JT, and OC. PITFALLS/AVOIDANCE OF COMPLICATIONS: Neurovascular injuries can be avoided by using intraoperative Doppler and nerve stimulator. Multilayer reconstruction with vascularized nasoseptal (NSF) and RP flaps minimize postoperative cerebrospinal fluid leak. VARIANTS AND INDICATIONS FOR THEIR USE: The contralateral transmaxillary approach provides an increased angle of access behind foramen lacerum and the petrous ICA.The endoscopic endonasal far-medial approach can be used for a variety of pathologies, including petroclival or JT meningiomas, chordomas and chondrosarcomas, and hypoglossal schwannomas, inferiorly extending cholesterol granulomas and even rare, ventral posterior inferior cerebellar artery aneurysms.The patients consented to the procedure.

Anteromedial Petrous (Gardner's) Triangle: Surgical Anatomy and Relevance for Endoscopic Endonasal Approach to the Petrous Apex and Petroclival Region.

BACKGROUND AND OBJECTIVES: Triangular corridors have been used as reliable surgical entry points for open transcranial approaches to the petrous apex (PA) and petroclival region (PCR). The endoscopic endonasal approaches have grown rapidly in the last decade, and the indications have advanced. The knowledge of accurate and reliable anatomic landmarks through endoscopic endonasal route is essential and remain to be established. The purpose of this study was to describe the feasibility and surgical exposure of the anteromedial petrous (Gardner's) triangle as a novel corridor to the PA and PCR. METHODS: Five anatomic specimens were dissected. The PA and PCR were accessed through endoscopic endonasal approaches and contralateral transmaxillary approach. The limits of the anteromedial petrous (Gardner's) triangle were identified and dissected and associated measurements performed. RESULTS: The dissection was divided into 6 steps. The limits of the anteromedial petrous (Gardner's) triangle were identified and defined by the paraclival internal carotid artery anterolaterally, the abducens nerve posteromedially, and the petroclival synchondrosis inferiorly. Three lines were established following the limits of the triangle. The mean distance of the anterolateral limit was 10.03 mm (SD = 0.94), of the posteromedial limit was 20.06 mm (SD = 2.90), and of the inferior limit was 17.99 mm (SD = 2.99). The mean area was 87.56 mm 2 (SD = 20.06). The 3 anatomic landmarks with a critical role to safely define the triangle were the pterygosphenoidal fissure, the petrosal process of the sphenoid bone, and the petroclival synchondrosis. CONCLUSION: The anteromedial (Gardner's) triangle is a well-defined bone corridor which provides access to the entire petrous bone and petroclival junction through endoscopic endonasal route. Regardless of the anatomic variations or tumor location, the landmarks of the abducens nerve, paraclival internal carotid artery, and petroclival synchondrosis are key for understanding lateral access to tumors extending from the clivus.

Endoscopic endonasal approach for resection of odontoid process, decompression of the cervicomedullary junction spinal cord, and resection of pannus.

Odontoid pannus is an abnormal collection of degenerative or inflammatory tissue on the C1-dens joint that can result in severe spinal cord compression myelopathy. Treatment options vary depending on severity and etiology. In cases of severe cord compression, surgical management could be either through a purely posterior approach or in combination with an anterior decompression via endoscopic endonasal approach (EEA). This case presents a 77-year-old female who underwent posterior cervical fixation for odontoid pannus causing dramatic cervical myelopathy who failed to improve over a 6-month period and required anterior transodontoid pannus resection and decompression via EEA. The video can be found here: https://stream.cadmore.media/r10.3171/2024.1.FOCVID23176.

American Rhinologic Society expert practice statement part 1: Skull base reconstruction following endoscopic skull base surgery.

The goal of this American Rhinologic Society expert practice statement (EPS) is to summarize the best available evidence for technical factors that optimize outcomes in skull base reconstruction following endoscopic skull base surgery for intradural pathologies. These topics include the use of free mucosal grafts versus vascularized pedicled nasoseptal flaps; the use of autologous versus synthetic grafts; and the roles of lumbar drains, dural sealants, and nasal packing. This EPS was developed following the recommended methodology and approval process as previously outlined. As there are a myriad of techniques and limited agreement on the accepted principles of skull base reconstruction, this EPS aims to summarize the existing evidence and provide clinically meaningful guidance on these divergent practices. Following a modified Delphi approach, five statements were developed, four of which reached consensus and one of which reached near consensus. These statements and the accompanying evidence are summarized along with an assessment of future needs.

Immunotherapy in the Management of Sinonasal Mucosal Melanoma: A Systematic Review.

OBJECTIVE: The aim of this work is to comprehensively review and synthesize the literature related to sinonasal mucosal melanoma (SNMM) treatment with immunotherapy, including potentially targetable genetic mutations, survival outcomes, and adverse events. DATA SOURCES: Embase, Cochrane, Scopus, and Web of Science. REVIEW METHODS: The study protocol was designed according to Preferred Reporting Items for Systematic Reviews and Meta-analysis statement. Databases were searched from inception through May 23, 2023. RESULTS: A total of 42 studies met inclusion criteria. Twenty-four of the included studies reported genetic mutations for a combined 787 patients with SNMM. 8.1% (95% confidence interval, CI: 7.6-8.6), 18.9% (95% CI: 18.1-19.8), and 8.5% (95% CI: 8.1-9.0) of reported patients were positive for BRAF, NRAS, and KIT mutations, respectively. The presence of brisk tumor-infiltrating lymphocytes was associated with improved recurrence-free survival and overall survival (OS). Six studies reported a combined 5-year OS after adjuvant immunotherapy treatment of 42.6% (95% CI: 39.4-45.8). Thirteen studies encompassing 117 patients reported adjuvant or salvage immune checkpoint inhibitor (ICI) immunotherapy response rates: 40.2% (95% CI: 36.8-43.6) had a positive response (tumor volume reduction or resolution). Eleven studies reported direct comparisons between SNMM patients treated with or without immunotherapy; the majority (7/11) reported survival benefit for their entire cohort or select subgroups of SNMM patients. With the transition to modern ICIs, there is a stronger trend toward survival improvement with adjuvant ICI. Tumors with Ki67 <40% may respond better to ICI's. CONCLUSION: ICI therapy can be an effective in select SNMM patients, especially those with advanced/metastatic disease.

The Prognostic Implications of Neutrophil-to-Lymphocyte Ratio in Olfactory Neuroblastoma.

OBJECTIVE: Olfactory neuroblastoma is a rare sinonasal malignancy with comparatively positive prognosis and survival, but with a range of biological behaviors that can be difficult to prognosticate with current means of risk stratification. Neutrophil-to-lymphocyte ratio (NLR) has been found across a diverse range of malignancies to be associated with poorer outcomes. This paper aims to elucidate the relationship of NLR with olfactory neuroblastoma to assess its prognostic value in this setting. STUDY DESIGN: Retrospective chart review. SETTING: A single tertiary care academic hospital. METHODS: The study cohort included all patients treated for initial presentation of olfactory neuroblastoma from 2004 to 2020. NLR was calculated from preoperative labs, and each patient was evaluated for Kadish staging, Hyams grade, intraoperative positive margin, use of adjuvant therapy, posttreatment recurrence, and death. All statistical analysis was conducted using R and relationship between NLR and variables was assessed via binomial logistic regression. RESULTS: Forty-four patients were included, 24 were male. Average age 52.8, average length of follow-up was 9.6 years. Patients were grouped by low (Kadish A/B) and advanced (Kadish C/D) stage, n = 23 and n = 21, respectively, and low (Hyams I/II) and high (Hyams III/IV) risk, n = 15 and n = 11, respectively. Advanced Kadish stage was associated with elevated NLR, odds ratio 5.69 [2.30, 20.7], P = .001. No other variables were associated with elevated NLR including Hyams grade, margin status, recurrence, and mortality. CONCLUSION: Higher Kadish grade is associated with elevated NLR which may provide novel prognostic value to current risk-stratifying systems.

A novel classification and management scheme for craniocervical junction disorders with ventral neural element compression.

OBJECTIVE: Craniocervical junction (CCJ) pathologies with ventral neural element compression are poorly understood, and appropriate management requires accurate understanding, description, and a more uniform nomenclature. The aim of this study was to evaluate patients to identify anatomical clusters and better classify CCJ disorders with ventral compression and guide treatment. METHODS: A retrospective review of adult and pediatric patients with ventral CCJ compression from 2008 to 2022 at a single center was performed. The incidence of anatomical abnormalities and compressive etiologies was assessed. Surgical approach, radiographic data, and outcomes were recorded. Association rules analysis (ARA) was used to assess variable clustering. RESULTS: Among 51 patients, the main causes of compression were either purely bony (retroflexed dens [n = 18]; basilar invagination [BI; n = 13]) or soft tissue (degenerative pannus [n = 16]; inflammatory pannus [n = 2]). The primary cluster in ARA was a retroflexed dens, platybasia, and Chiari malformation (CM), and the secondary cluster was BI, C1-2 subluxation, and reducibility. These, along with degenerative pannus, formed the three major classes. In assessing the optimal treatment strategy, reducibility was evaluated. Of the BI cases, 12 of the 13 patients had anterolisthesis of C1 that was potentially reducible, compared with 2 of the 18 patients with a retroflexed dens (both with concomitant BI), and no pannus cases. The mean C1-2 facet angle was significantly higher in BI at 32.4°, compared with -2.3° in retroflexed dens and 8.1° in degenerative pannus (p < 0.05). Endonasal decompression with posterior fixation was performed in 48 (94.0%) of the 51 patients, whereas posterior reduction/fixation alone was performed in 3 patients (6.0%). Of 16 reducible cases, open posterior reduction alone was successful in 3 (60.0%) of 5 cases, with all successes containing isolated BI. Reduction was not attempted if vertebral anatomy was unfavorable (n = 9) or the C1 lateral mass was absent (n = 5). The mean follow-up was 28 months. Symptoms improved in 88.9% of patients and were stable in the remaining 11.1%. Tracheostomy and percutaneous G-tube placement occurred in 7.8% and 11.8% of patients, respectively. Reoperation for an endonasal CSF leak repair or posterior cervical wound revision both occurred in 3.9% of patients. CONCLUSIONS: In classifying, one cluster caused decreased posterior fossa volume due to an anatomical triad of retroflexed dens, platybasia, and CM. The second cluster caused pannus formation due to degenerative hypertrophy. For both, endonasal decompression with posterior fixation was ideal. The third group contained C1 anterolisthesis characterized by a steep C1-2 facet angle causing reducible BI. Posterior reduction/fixation is the first-line treatment when anatomically feasible or endonasal decompression with in situ posterior fixation when anatomical constraints exist.

Electromyographic predictors of abducens nerve palsy after endoscopic skull base surgery.

OBJECTIVE: Recovery of abducens nerve palsy (ANP) after endoscopic endonasal skull base surgery (ESBS) has been shown to be potentially predicted by postoperative ophthalmological examination. Triggered electromyography (t-EMG) and free-run electromyography (f-EMG) activity provide an intraoperative assessment of abducens nerve function, but associations with long-term ANP outcomes have not been explored. The objective of this study was to describe intraoperative abducens EMG characteristics and determine whether these electrophysiological profiles are associated with immediately postoperative and long-term ANP outcomes after ESBS. METHODS: The authors conducted a 5-year (2011-2016) retrospective case-control study of patients who underwent ESBS in whom the abducens nerve was stimulated (t-EMG). Electrophysiological metrics were compared between patients with a new postoperative ANP (cases) and those without ANP (controls). Pathologies included chordoma, pituitary adenoma, meningioma, cholesterol granuloma, and chondrosarcoma. Electrophysiological data included the presence of abnormal f-EMG activity, t-EMG stimulation voltage, stimulation threshold, evoked compound muscle action potential (CMAP) amplitude, onset latency, peak latency, and CMAP duration at various stages of the dissection. Controls were selected such that pathologies were similarly distributed between cases and controls. RESULTS: Fifty-six patients were included, 26 with new postoperative ANP and 30 controls without ANP. Abnormal f-EMG activity (28.0% vs 3.3%, p = 0.02) and lack of response to stimulation (27% vs 0%, p = 0.006) were more frequent in patients with immediately postoperative ANP than in controls. Patients with immediately postoperative ANP also had a lower median CMAP amplitude (35.0 vs 71.2 µV, p = 0.02) and longer onset latency (5.2 vs 2.8 msec, p = 0.04). Comparing patients with transient versus persistent ANP on follow-up, those with persistent ANP tended to have a lower CMAP amplitude (12.8 vs 57 µV, p = 0.07) and higher likelihood of not responding to stimulation at the end of the case (45.5% vs 7.1%, p = 0.06). Abnormal f-EMG was not associated with long-term ANP outcomes. CONCLUSIONS: The presence of f-EMG activity, lack of CMAP response to stimulation, decreased CMAP amplitude, and increased CMAP onset latency were associated with immediately postoperative ANP. Long-term ANP outcomes may be associated with t-EMG parameters, including whether the nerve is able to be stimulated once identified and CMAP amplitude. Future prospective studies may be designed to standardize abducens nerve electrophysiological monitoring protocols to further refine operative and prognostic utility.