Diagnosis and management of a rare case of clival chordoma in a young male patient.

Chordomas are uncommon bone slow-growing tumors developing from remnants of the notochord. They are typically seen in adults, and rarely in children. We present the case of a 16-year-old male patient with a clival chordoma, presenting with progressive headache and diplopia. In this case report we aim to provide an educational explanation of the radiological findings, diagnostic challenges, and therapeutic and management strategies.

Assessing survival outcomes and complication profiles following surgical excision and radiotherapy as interventions for skull base chordoma: a systematic review of operative margins and surgical approaches.

INTRODUCTION: Despite their precarious behavioral classification (benign and low grade on histopathology yet behaviorally malignant), great strides have been taken to improve prognostication and treatment paradigms for patients with skull base chordoma. With respect to surgical techniques, lateral transcranial (TC) approaches have traditionally been used, however endoscopic endonasal approaches (EEA) have been advocated for midline lesions. Nonetheless, due to the rarity of this pathology (0.2% of all intracranial neoplasms), investigations within the literature remain limited to small retrospective series. Furthermore, radiotherapeutic treatments investigated to date have proven largely ineffective. METHODS: Accordingly, we performed a systematic review in order to profile surgical and survival outcomes for skull base chordoma. Fixed and random-effect meta-analyses were performed for categorical variables including GTR, STR, 5-year OS, 10-year OS, 5-year PFS, and 10-year PFS. Additionally, we pooled eligible studies for formal meta-analysis to compare outcomes by surgical approach (lateral versus midline). Statistical analyses were performed using R Studio 'metafor' package or Cochrane Review Manager. Furthermore, meta-analysis of pooled mortality rates and sub-analyses of operative margin and surgical complications were used to compare midline versus lateral approaches via the Mantel-Haenszel method. We considered all p-values < 0.05 to be statistically significant. RESULTS: Following the systematic search and screen, 55 studies published between 1993 and 2022 reporting data for 2453 patients remained eligible for analysis. Sex distribution was comparable between males and females, with a slight predominance of male-identifying patients (0.5625 [95% CI: 0.5418; 0.3909]). Average age at diagnosis was 42.4 ± 12.5 years, while average age of treatment initiation was 43.0 ± 10.6 years. Overall, I2 value indicated notable heterogeneity across the 55 studies [I2 = 56.3% (95%CI: 44.0%; 65.9%)]. With respect to operative margins, the rate of GTR was 0.3323 [95% CI: 0.2824; 0.3909], I2 = 91.9% [95% CI: 90.2%; 93.4%], while the rate of STR was significantly higher at 0.5167 [95% CI: 0.4596; 0.5808], I2 = 93.1% [95% CI: 91.6%; 94.4%]. The most common complication was CSF leak (5.4%). In terms of survival outcomes, 5-year OS rate was 0.7113 [95% CI: 0.6685; 0.7568], I2 = 91.9% [95% CI: 90.0%; 93.5%]. 10-year OS rate was 0.4957 [95% CI: 0.4230; 0.5809], I2 = 92.3% [95% CI: 89.2%; 94.4%], which was comparable to the 5-year PFS rate of 0.5054 [95% CI: 0.4394; 0.5813], I2 = 84.2% [95% CI: 77.6%; 88.8%] and 10-yr PFS rate of 0.4949 [95% CI: 0.4075; 0.6010], I2 = 14.9% [95% CI: 0.0%; 87.0%]. There were 55 reported deaths for a perioperative mortality rate of 2.5%. The relative risk for mortality in the midline group versus the lateral approach group did not indicate any substantial difference in survival according to laterality of approach (-0.93 [95% CI: -1.03, -0.97], I2 = 95%, (p < 0.001). CONCLUSION: Overall, these results indicate good 5-year survival outcomes for patients with skull base chordoma; however, 10-year prognosis for skull base chordoma remains poor due to its radiotherapeutic resistance and high recurrence rate. Furthermore, mortality rates among patients undergoing midline versus lateral skull base approaches appear to be equivocal.

Lynch syndrome-associated chordoma with high tumor mutational burden and significant response to immune checkpoint inhibitors.

Chordoma is a rare malignant bone tumor arising from notochordal tissue. Conventional treatments, such as radical resection and high-dose irradiation, frequently fail to control the tumor, resulting in recurrence and re-growth. In this study, genetic analysis of the tumor in a 72-year-old male patient with refractory conventional chordoma of the skull base revealed a high tumor mutational burden (TMB) and mutations in the MSH6 and MLH1 genes, which are found in Lynch syndrome. The patient and his family had a dense cancer history, and subsequent germline genetic testing revealed Lynch syndrome. This is the first report of a chordoma that has been genetically proven to be Lynch syndrome. Chordomas usually have low TMB; however, this is an unusual case, because the TMB was high, and immune checkpoint inhibitors effectively controlled the tumor. This case provides a basis for determining the indications for immunotherapy of chordoma based on the genetic analysis. Therefore, further extensive genetic analysis in the future will help to stratify the treatment of chordoma.

Impact of Treatment Modalities upon Survival Outcomes in Skull Base and Clival Chordoma: An NCDB Analysis.

Objectives Skull base chordomas are locally aggressive malignant tumors derived from the notochord remnant. There are limited large-scale studies examining the role and extent of surgery and radiation therapy. Design Analysis of the National Cancer Database (NCDB) was performed to evaluate the survival outcomes of various treatments, and to assess for predictors of overall survival (OS). Participants This is a retrospective, population-based cohort study of patients diagnosed with a clival/skull base chordoma between 2004 and 2015 in the NCDB. Main Outcome Measures The primary outcome was overall survival (OS). Results In all, 468 cases were identified. Forty-nine percent of patients received surgery and 20.7% had positive margins. Mean age at diagnosis was 48.4 years in the surgical cohort, and 55% were males. Of the surgical cohort, 33.8% had negative margins, 20.7% had positive margins, and 45.5% had unknown margin status. Age ≥ 65 (hazard ratio [HR]: 3.07; 95% confidence interval [CI]: 1.63-5.76; p < 0.001), diagnosis between 2010 and 2015 (HR: 0.49; 95% CI: 0.26-0.90; p = 0.022), tumor size >5 cm (HR: 2.29; 95% CI: 1.26-4.15; p = 0.007), and government insurance (HR: 2.28; 95% CI: 1.24-4.2; p = 0.008) were independent predictors of OS. When comparing surgery with or without adjuvant radiation, no survival differences were found, regardless of margin status ( p = 0.66). Conclusion Surgery remains the mainstay of therapy. Advanced age (>65 years), large tumor size, and government insurance were predictors of worse OS. Whereas negative margins and the use of adjuvant radiation did not appear to impact OS, these may very well reduce local recurrences. A multidisciplinary approach is critical in achieving optimal outcomes in this challenging disease.

A 13-year patient journey of infant giant clival chordoma: case report and literature review.

Chordomas are rare malignant bone tumours that develop from the ectopic remnants of the embryonic notochord. In contrast to adults, the majority in children under 16 present intra-cranially (63%). In 2006, we reported the youngest case of a large clival chordoma, a 15-week old baby, the second case to present without skull base involvement and the fourth case of chordoma in a patient with tuberous sclerosis (TS) Kombogiorgas (Childs Nerv Syst 22(10):1369-1374, 2006). In this report, we provide an update on this patient's journey through a range of therapeutic options and summarize an update of the literature, since 2006, for this patient group.

Intradural spinal seeding metastasis of clival chordoma: a case report.

Background: Clival chordoma is a locally aggressive tumor originating from remnants of the embryologic notochord. Although clival chordomas account for only 0.2% of all central nervous system tumors, they are characterized by local invasion and destruction, dural invasion, bone erosion, and cranial nerve palsy, and even metastasis. Case Description: We report a case of a 49-year-old female with an intradural spinal seeding metastasis 16 months after the initial endoscopic endonasal surgery (EES) for a clival chordoma. Gross total resection of tumor in upper clival region was achieved after initial EES and pathology revealed a classic chordoma. After 10 months, follow-up magnetic resonance (MR) showed a recurrence in situ and gamma knife was applied. After 16 months, the patient complained of neck pain and MR showed a new lesion in the spinal canal at C1 to C2 level. After craniotomy, the lesion in the spinal canal was totally removed, and pathology confirmed a chordoma with increased proliferative potential. The spinal chordoma might have occurred as a result of intradural spinal seeding metastasis through cerebral spinal fluid the during the initial operation. Conclusions: Chordomas are not only locally aggressive but also unpredictable and may metastasize through cerebral spinal fluid. Intensive follow-up is of great importance in the long term postoperatively time for clival chordoma patients.

Unilateral Compressive Optic Neuropathy As the Presenting Manifestation of Clival Chordoma: A Case Report.

The optic nerve(s) may be compressed by a number of intracranial and intraorbital masses. Compression may be isolated to the optic nerve or may involve other intracranial or intraorbital structures with variable presentation. A 26-year-old man presented with complaints of progressive painless visual loss in the right eye for eight months. Examination revealed isolated unilateral optic atrophy consistent with a diagnosis of compressive optic neuropathy. Magnetic resonance imaging of the brain showed compression of the anterior visual pathways due to a lesion radiologically compatible with clival chordoma. He underwent subtotal neurosurgical resection and pathology was consistent with chordoma. Although rare, isolated unilateral visual loss may be the only presenting manifestation of clival chordoma.

Surgical Outcomes of Clival Chordoma Through Endoscopic Endonasal Approach: A Single-Center Experience.

Objective: Clival chordoma is a locally aggressive tumor with low metastatic potential. In the past decade, endoscopic endonasal approach (EEA) for clival chordoma has had a higher resection rate and a lower morbidity rate than transcranial approaches. Here, we present our initial single-center experience after EEA of clival chordomas. Patients and methods: This study retrospectively analyzed 17 consecutive patients with clival chordoma who received EEA in our department between March 2015 and September 2021. The operation was performed by a single surgeon with EEA. The clinical and pathological characteristics were analyzed along with the surgical outcomes and complications. Results: A total of 17 consecutive patients with clival chordoma received EEA with a median follow-up of 29.2 months (range 1-79). Gross total resection (GTR) was performed in 7 cases (41%), subtotal resection (STR) in 7 case (41%) and partially resection (PR) in 3 cases (18%). Cerebrospinal fluid leakage occurred in 2 cases (12%) and meningitis developed in 3 patients (18%) which were all successfully treated with intravenous antibiotics without any complications. There were no perioperative deaths or new focal neurological deficits postoperatively. Four in 7 patients with STR have had radiotherapy while the other three chose to be monitored. Till the last follow-up, three patients in STR group who received radiotherapy (3 in 4) had no tumor regrowth, while one in STR group with radiotherapy (1 in 4) showed tumor progression. Two patients in STR group without radiotherapy (2 in 3) showed stable tumor while the left one (1 in 3) showed tumor progression. One patient in the PR group died of tumor progression 2 years postoperation and the other one showed tumor progression and died of lung cancer 1 year postoperation. In addition, 1 in 7 patients with GTR had tumor recurrence in situ after 10 months and developed surgical pathway seeding in the spinal canal in C1 after 16 months. No recurrence occurred in the other 6 cases with GTR during the follow-up. Conclusion: Although more cases are needed, our case series showed EEA is a safe and reliable method for clival chordoma with high resection rates and low morbidity rates. GTR without tumor residuum would improve the outcome.

Reconstruction and Cerebrospinal Fluid Leaks in Endoscopic Endonasal Approach for the Management of Clival Chordomas-A Systematic Review.

The success of the endoscopic endonasal approach (EEA) to surgically manage clival chordomas (CC) relies on robust repair methods to reduce complications, such as cerebrospinal fluid (CSF) leaks. Our study aims to evaluate the existing literature to assess reconstructive techniques utilised and post-operative CSF leak rates in this cohort. A systematic review and analysis was performed of all published data related to CC patients managed with an EEA. A total of 24 articles were included, representing 363 patients and 396 procedures. A variety of reconstruction methods were used with 95.9% of studies using an intracranial repair graft, 70.8% using a nasoseptal flap (NSF), 62.5% using glue/haemostat, 58.3% using nasal packs and 75.0% employing multi-layered reconstruction. Post-operative CSF leak rate was 10.1%. The leak rate was less in subgroups where a NSF was used (9.4%) although this was not statistically significant (p = 0.273). There were no differences in leak rates when glue/haemostat (p = 0.139) or nasal packs (p = 0.550) were used. Our review is the most up-to-date synthesis of the existing literature surrounding the EEA to CCs assessing reconstruction and post-operative CSF leaks. It demonstrates most authors employ a multi-layered reconstruction method. The lack of statistical significance observed for CSF leaks in subgroups is likely due to a variety of cofounding surgeon and patient factors. Higher quality prospective randomised multi-centric studies, with reporting of specific repair techniques will enable future systematic reviews to provide a more accurate consensus regarding optimal methods of reconstruction in this field.

An Integrated Management Paradigm for Skull Base Chordoma Based on Clinical and Molecular Characteristics.

Objective Previous work categorized skull base chordoma (SBC) into three genetic risk groups based on 1p36 and homozygous 9p21(p16) deletions, accounting for a wide variability in prognosis (A = low-risk, B = intermediate-risk, C = high-risk). However, it remains unclear how these groups could guide management. Study Design By integrating surgical outcome and adjuvant radiation (AdjXRT) information with genetic data on 152 tumors, we sought to develop an evidence-based management algorithm for SBC. Results Gross total resections (GTRs) were associated with improved progression free survival (PFS) in all genetic groups. For Group C tumors, GTR and AdjXRT independently contributed to PFS (multivariate Cox proportional hazard ratio [HR] = 0.14, p = 0.002, and HR = 0.40, p = 0.047, respectively). For Group B tumors, AdjXRT improved outcomes only when GTR was not feasible (log-rank p = 0.008), but not following GTR (log-rank p = 0.54). However, 24 of 25 Group A tumors underwent GTR, and AdjXRT for these did not confer any benefit (log-Rank p = 0.285). The high GTR rates in Group A could be explained by smaller tumor sizes (mean = 0.98cc/4.08cc/4.92cc for Group A/B/C, respectively, p = 0.031) and lack of invasiveness. Group A tumors were also more frequently diagnosed in young people ( p = 0.002) as asymptomatic lesions ( p = 0.001), suggesting that they could be precursors to tumors in higher risk groups. Conclusion Genotypic grouping by 1p36 and homozygous 9p21(p16) deletions can predict prognosis in SBC and guide management. GTR remains the cornerstone of SBC treatment and can be sufficient without AdjXRT in low and intermediate risk tumors. Low-risk tumors are associated with a less invasive phenotype, which makes them more amenable to GTR.

Numerical Simulation of Nasal Airflow Aerodynamics, and Warming and Humidification in Models of Clival Chordoma Pre and Post-Endoscopic Endonasal Surgery.

OBJECTIVES: To study the effect of endoscopic endonasal surgery on nasal function for the treatment of clival chordoma. METHODS: Pre and post-operative computed tomography (CT) scans of a case of chordoma treated with an endoscopic endonasal approach (EEA) were collected retrospectively, and models of the nasal cavity were reconstructed so that a subsequent numerical simulation of nasal airflow characteristics, warming, and humidification could be conducted. RESULTS: Middle turbinectomy resulted in redistribution of airflow within the nasal cavity, and the most significant changes occurred in the middle section. Consistent with the results of airflow evaluation, it was found that the change in nasal anatomical structure significantly reduced warming and humidification. Nasal humidification decreased substantially when postoperative loss of mucosa was taken into consideration. The H2O mass fraction of pharynx in inspiration phase were significantly correlated with airway surface-to-volume ratio (SVR). CONCLUSIONS: The EEA for chordoma significantly affected nasal function. Attention should be paid to the protection of nasal structure and the associated mucosa.

Spontaneous CSF rhinorrhea as a presenting symptom of a clival chordoma.

CSF rhinorrhea is a rare presenting symptom of a clival chordoma as these tumors do not tend to show dural invasion as a histological feature. Here we discuss the case of a 61 years old female with spontaneous rhinorrhea secondary to a clival chordoma, and the value of some specific MRI sequences in accurate identification of a tumor with such atypical presentation, enabling the surgeon to plan accordingly.

Microsurgical versus endoscopic trans-sphenoidal approaches for clivus chordoma: a pooled and meta-analysis.

Chordoma is a rare slow-growing neoplastic bone lesion. However, they show an invasive local growth and high recurrence rate, leading to an overall survival rate of 65% at 5 years and 35% at 10 years. We conducted a pooled and meta-analysis comparing recurrence rate, post-operative-complications, and survival in patients undergoing either microsurgical (MA) or endoscopic approaches (EA). Search of literature was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to identify surgical series of clivus chordomas published between January 1990 and March 2018 on Pubmed, Scopus, and Cochrane. Two different statistical analyses have been performed: a pooled analysis and a single-arm meta-analysis of overall recurrence rate and subgroup meta-analysis of complications in the subgroups open surgery and endoscopic surgery. After full-text screening, a total of 58 articles were included in the pooled analysis and 27 studies were included for the study-level meta-analysis. Pooled analysis-the extent of resection was the only association that remained significant (subtotal: HR = 2.18, p = 0.004; partial: HR = 4.40, p < 0.001). Recurrence was more prevalent among the surgical patients (45.5%) compared to endoscopic ones (23.7%). Meta-analysis-results of the cumulative meta-analysis showed an overall rate of recurrence of 25.6%. MA recurrence rate was 31.8% (99% CI 14-52.8), EA recurrence rate was 19.4% (5.4-39.2). CSF leak rate for the endoscopic group was 10.3% (99%CI 5-17.3) and 9.5% (99%CI 1.2-24.6) for the open surgery group. The partial removal versus total removal has an influence on recurrence rate (p < 0.001). MA recurrence rate was 31.8%; EA recurrence rate was 19.4%. The extent of resection is confirmed as a statistically significant factor affecting the risk for recurrence both with the pooled analysis and with the meta-analysis. Meta-analysis demonstrated that older patients tend to recur more than young patients, especially in surgical group.

Supracerebellar Approach for Clival Chordomas: Technical Note.

BACKGROUND: The conventional retrosigmoid and lateral supracerebellar approach was used for surgery in 5 select cases of large chordomas. METHODS: Patients were treated during 2011 and 2019. Location of the tumor in the depth from surface, wide tumor extensions, and intimate relationships with critical neural and vascular lesions made the approach selection a formidable challenge. RESULTS: The discussed approach provided a satisfactory and wide exposure that permitted circumferential dissection of the tumor. Maneuvering the angulation of microscope provided access to the part of tumor that extended in the region of cavernous sinus. CONCLUSIONS: Radical resection of all the tumors was achieved.

Pediatric sinonasal and skull base lesions.

Pediatric skull base lesions are complex and challenging disorders. Safe and comprehensive management of this diverse group of disorders requires the expertise of an experienced multidisciplinary skull base team. Adult endoscopic skull base surgery has evolved due to technologic and surgical advancements, multidisciplinary team approaches, and continued innovation. Similar principles continue to advance the care delivered to the pediatric population. The approach and management of these lesions varies considerably based on tumor anatomy, pathology, and surgical goals. An understanding of the nuances of skull base reconstruction unique to the pediatric population is critical for successful outcomes.

Extreme Lateral Transodontoid Approach for Resection of Clival Chordoma: 2-Dimensional Operative Video.

This 15-yr-old girl presented with nasal obstruction and dysphagia of duration 3 mo and 8 to 10 pounds of weight loss. On examination, she had a hoarse voice and left tongue deviation without weakness or myelopathy. Computed tomography (CT) demonstrated an erosive lesion arising from the clivus and left occipital condyle. Magnetic resonance imaging (MRI) demonstrated a T1-isointense, T2-hyperintense, enhancing mass centered at the occipital condyle and extending into the craniovertebral junction (CVJ), causing severe brainstem compression and extending inferiorly to C2 and anteriorly into the retropharyngeal space. The patient underwent transoral biopsy to confirm the diagnosis of chordoma and complete tumor resection via a left extreme lateral transodontoid (ELTO) approach. This approach was chosen because it provides bilateral exposure to the ventral CVJ and retropharyngeal space and allows for complete tumor removal using a single approach, although it requires an experienced surgeon. The ELTO incision should provide adequate exposure for occipitocervical fusion (OCF) after the destabilization of the CVJ. Transposition of the vertebral artery and odontoidectomy are key maneuvers that provide exposure to the ventral CVJ bilaterally. Dural closure is performed primarily and augmented with fat, fibrin glue, and temporary cerebrospinal fluid diversion. Postoperative MRI showed a gross-total resection and decompression of the brainstem at the CVJ. The patient remained in a cervical collar until OCF. Postoperatively, she had left vocal cord paralysis and moderate weakness with left arm abduction at the deltoid. At 2-mo follow-up, she had improved lower cranial neuropathies, tolerated oral intake, and was scheduled to begin proton beam therapy. The patient provided consent for publication.

The timing of fusion surgery for clival chordoma with occipito-cervical joint instability: before or after tumor resection?

Clival chordoma with occipito-cervical (OC) joint invasion can result in preoperative and postoperative instability. The authors investigate the appropriate timing of OC fusion to prevent instability-, fusion-, and surgery time-related morbidity. Twenty-two consecutive patients underwent surgery for clival chordoma from December 2008 to September 2014. OC fusion was performed for patients with OC joint invasion and instability due to preoperative destruction of the occipital condyle or extensive postoperative condylectomy. The data in relation to OC joint instability, fusion, and surgery time were analyzed retrospectively and compared between OC fusion before and after tumor resection. Of the 22 patients, 8 with tumor invasion of the OC joint underwent OC fusion. OC fusion was performed after tumor resection in one-stage for four patients and before tumor resection in two-stage for four patients. There was OC joint instability from tumor destruction of the occipital condyle in seven patients (87.5%). Patients with OC fusion after tumor resection encountered complications such as surgery site wound dehiscence, encephalitis, and cardiac arrest with consequent mortality in one patient. These complications were avoided in subsequent patients where OC fusion was performed before tumor resection. There were no differences in the extent of tumor resection between OC fusion before and after tumor resection. Two-stage OC fusion before tumor resection can reduce instability-, fusion-, and surgery time-related morbidity and achieve feasible tumor resection when OC joint instability is expected. The extent of tumor invasion and brain stem compression should be considered when fusion precedes tumor resection.

Clinical classification of clival chordomas for transnasal approaches.

Endoscopic endonasal approaches (EEAs) are ideal for most chordomas, but there is little information regarding the practical clinical classification of clival chordomas to guide surgery with EEAs. This article investigates a relatively concise and practical clinical classification system for clival chordomas and summarizes the clinical characteristics and operative key points of different clinical types. Here, 55 patients with clival chordomas treated through EEAs from 2012 to 2017 were retrospectively reviewed. Depending on the origin of the notochord and the growth pattern of the tumor, with our introduced Wang's line, these cases of clival chordoma were divided into types I-IV. There were 14 cases of type I-A, 7 cases of type I-B, 10 cases of type II, 10 cases of type III-A, 7 cases of type III-B, and 7 cases of type IV. The gross total resection (GTR) rate of primary and recurrent type I tumors was 64% and 25%, and residual tumors were found mainly in cases with involvement of the cavernous sinus or the posterior upper part of the dorsum sella. The GTR rate of primary and recurrent type II tumors was 85% and 66.6%, respectively. Residual tumors were found in cases with involvement of the petrous apex. The GTR rate of primary and recurrent type III tumors was 75% and 20%, and residual tumors were found in cases with involvement of the parapharyngeal space and dorsal side of C1-2. Residual type I-B and type III-B tumors were found when there was BA or VA adhesion or brain stem invasion. Our new classification method proposed here can be used to guide the resection of clival chordomas through EEAs.

Radial Forearm Free Tissue Transfer to Clival Defect.

Introduction Reconstruction of craniocervical junction (CCJ) defects after endoscopic endonasal skull base surgery (ESBS) remains challenging, despite advancements in vascularized intranasal and regional flaps. Microvascular free tissue transfers have revolutionized reconstruction in open skull base surgery but have been utilized rarely in ESBS. We describe the use of a radial forearm free flap (RFFF) for reconstruction of a recalcitrant CCJ defect after resection of a clival chordoma. Case Report A 54-year-old female who underwent ESBS for a clival chordoma complicated by a C1-C2 epidural abscess after proton beam therapy presented with pneumocephalus 4 years after her resection ( Fig. 1 ). At the CCJ, she developed a 1-cm skull-base defect. An occult cerebrospinal fluid (CSF) leak persisted despite an extracranial pericranial flap and a lateral nasal wall flap. Her definite reconstruction was a RFFF inset through a transmaxillary approach. Using a maxillary vestibular incision, anterior, lateral, and medial maxillotomies allowed the introduction of the flap into the nasal cavity and the passage of the RFFF pedicle across the posterior maxillary wall, into the premassateric space and to the facial vessels at the mandible. An endonasal inset supplemented with transoral suturing of the distal end of the flap to the posterior oropharynx halted further CSF egress. Vascularization of the flap was confirmed with intraoperative indocyanine green angiography and postoperative computed tomography (CT) angiography and magnetic resonance imaging (MRI). Conclusion A RFFF inset through a transmaxillary approach to the facial vessels has an adequate reconstructive surface and pedicle to cover the central and posterior fossa skull base after ESBS ( Fig. 2 ). The link to the video can be found at: https://youtu.be/rQ5vJKyD5qg .

ICAR: endoscopic skull-base surgery.

BACKGROUND: Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS). METHODS: Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus. RESULTS: The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated. CONCLUSION: A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.