{"paper_id":"31c2ee99-e1c1-4ea0-a088-6b31aa7b0f16","body_text":"Neuronavigation assisted Endoscopic Endonasal Surgery for Skull Base Chordomas: treatment and outcome analysis in a consecutive case series of 12 patients | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Neuronavigation assisted Endoscopic Endonasal Surgery for Skull Base Chordomas: treatment and outcome analysis in a consecutive case series of 12 patients Guanlin Huang, Qiuhua Jiang, Wentao Lai, Xiaoping Zhou, Qi Zhong, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8954762/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 11 You are reading this latest preprint version Abstract Skull base chordomas can be challenging to resect, and the degree of surgical resection is highly correlated with prognosis. With the rapid development of imaging, neuronavigation, and endoscopy, these technologies provide good technical support for improving the gross total resection rate of skull base clivus chordomas. Objective : To analyze the clinical outcomes and extent of resection of neuronavigation-assisted endoscopic endonasal surgery in the treatment of skull base chordomas. Methods : We retrospectively analyzed 12 patients (six males and six females, aged 9–70 years) with skull base chordomas in the Department of Neurosurgery of Ganzhou People's Hospital from May 2018 to April 2020. Results : During the operation, 6 cases were exposed to the paraclival internal carotid artery, two patients experienced cerebrospinal fluid leakage before the operation, and four patients had tumors that broke through the dura, grew into the posterior cranial fossa, and adhered closely to the brain stem. Gross total resection was achieved in 66.67% (8 of twelve cases), and subtotal resection in 33.33% (4 of twelve cases). All patients were followed for 40–59 months after the operation. The patients' symptoms improved postoperatively. Conclusions : Neuronavigation-assisted EES is an effective approach for treating skull base chordomas. Chordomas Skull base Neuronavigation Endoscopy Clivus Figures Figure 1 Figure 2 Introduction Chordomas are bone tumors that originate from the primitive notochord along the spinal axis, and the two ends of the vertebral axis — sacrococcygeal and clival regions — are the most common sites [ 1 ] . Clival chordomas are aggressive, pathologically low-grade malignant tumors and usually exhibit midline presentation. Surgical resection is the first choice for skull base clivus chordomas, and the degree of surgical resection is highly correlated with the prognosis [ 2 ] . These tumors are located deeply, adjacent to important nerves and blood vessels, and they invade widely. Therefore, total resection is difficult and the postoperative recurrence rate is high [ 3 , 4 ] . With the rapid development of imaging, neuronavigation and endoscopy, these technologies provide good technical support for improving the total resection rate of skull base clivus chordomas [ 5 ] . We retrospectively analyzed 12 patients with skull base chordomas in the Department of Neurosurgery of Ganzhou People's Hospital from May 2018 to April 2020. Patients and Methods Patient Data We retrospectively analyzed 12 patients with skull base chordomas in the Department of Neurosurgery at Ganzhou People's Hospital between May 2018 and April 2020. All 12 patients were reviewed for age, sex, presenting symptoms, preoperative physical examination findings, and imaging findings (Table 1 ). Table 1 clinical and tumor characteristics of skull base chordoma patients Patient no. Symptoms Physical examination Tumor dimensions (mm) Location enhanced MRI soft group or firm group course of disease (days) 1 diplopia diplopia 30.6×28.8×28.2 Upper-middle clivus No enhancement soft 30 2 CSF leakage CSF leakage 30.3×34.4×22.5 sphenoid sinus,Upper-middle clivus,interpeduncular cistern,the prepontine cistern No enhancement soft 4 3 Headache with double vision, blepharoptosis and dysphagia double vision, blepharoptosis and dysphagia 28.8×38.4×34.2 sphenoid sinus,Upper-middle clivus,interpeduncular cistern,the prepontine cistern slightly enhancement soft 270 4 Headache and dizziness none 26.7×25.4×29.2 sphenoid sinus,Upper-middle clivus,right Cavernous sinus moderate enhancement soft 7 5 Headache and dizziness none 36.0×32.4×50.4 sphenoid sinus,Upper-middle moderate enhancement soft 14 6 Headache none 37.8×48.2×34.2 sphenoid sinus,Upper-middle clivus,interpeduncular cistern,the prepontine cistern strong enhancement firm 30 7 Headache none 54.3×46.6×29.5 sphenoid sinus,Ethmoid sinus,Upper-middle clivus,right Cavernous sinus strong enhancement firm 60 8 Facial pain and swelling none 39.6×48.3×41.5 maxillary sinus, pterygopalatine fossa and infratemporal fossa strong enhancement firm 180 9 Headache with blepharoptosis and dysphagia blepharoptosis and dysphagia 46.1×54.7×56.2 sphenoid sinus, whole clivus,pterygopalatine fossa and infratemporal fossa,right Cavernous sinus strong enhancement firm 30 10 Headache with CSF leakage CSF leakage 24.6×19.2×37.5 sphenoid sinus,Upper-middle clivus No enhancement soft 12 11 rhinobyon rhinobyon 84×78×82 sphenoid sinus, ethmoid sinus, turbinate,whole clivus, middle cranial fossa, posterior fossa,pterygopalatine fossa and infratemporal fossa, Cavernous sinus strong enhancement firm 365 12 Headache none 26.6×31.4×30.2 Upper-middle clivus moderate enhancement firm 60 Imaging Data All patients underwent both CT and MRI of the nasopharynx and skull base before surgery. On CT, most of the bone destruction in the clivus could be observed, and the bone destruction area was replaced by a soft tissue mass. The boundary between the tumor and normal bone was unclear. Residual bone fragments and patchy calcifications could be observed in the lesion, or the tumor had invaded the surrounding anatomical spaces. Intracranial pneumatosis was observed in 2 patients with cerebrospinal fluid leakage (Fig. 1 ). On MRI, most of the tumors showed T1 equal or slightly low signal, and a few lesions showed spotty and flaky high signal; T2 showed mostly high signal, with scattered low signal within. Regarding enhancement patterns, three cases showed no obvious enhancement, one case showed slight enhancement, three cases showed moderate enhancement, and five cases showed obvious enhancement. The tumors of all 12 patients were located in the midline of the skull base or extended to both sides, including the following distributions: two in the middle and upper clivus; three in the sphenoid sinus and middle and upper clivus; three in the sphenoid sinus, middle and upper clivus, interpeduncular cistern, and prepontine cistern; one in the sphenoid sinus, ethmoid sinus, middle and upper clivus, and right cavernous sinus; one in the sphenoid sinus, upper, middle, and lower clivus, right cavernous sinus, pterygopalatine fossa and infratemporal fossa; and one that invaded the sphenoid sinus, maxillary sinus, and pterygopalatine fossa. The tumors extended to the left and right spaces of cavernous ICA or paraclival and lacerum ICA, measuring approximately 6.51–26.17 mm in width and 13.36–43.37 mm in length, and extended to the dorsum sellae and posterior clinoid process region, measuring approximately 22.53–56.18 mm superoinferiorly and 19.23–54.74 mm anteroposteriorly. Surgical Technique All patients underwent endoscopic endonasal transclival surgery with the neuronavigation system. Preoperative examinations and preparations included: ⑴pituitary hormone, thyroid hormone and cortisol levels; (2) visual acuity, visual field and fundus examination; (3) CT examination; (4) MRI scanning; (5) neuronavigation data preparation: CT and MR image data were fused into the neuronavigation system before the operation, followed by image fusion and 3D reconstruction; (6) preoperative nasal irrigation. The main equipment used during the operation included: German Karl Storz supporting instruments and ultra-high definition neuroendoscope system, 4 mm diameter endoscope (0° and 45°), video acquisition system, and display from Karl Storz company; Medtronic high-speed grinding and drilling system; and German BrainLAB neuronavigation system and its accessories. We mainly performed EES using the binostril four-hand technique, and the three surgeons' five-hand technique was used when necessary. The main operation steps were as follows: The patient underwent general anesthesia with endotracheal intubation, was placed in the supine position, the dental pad was removed, the endotracheal tube was moved to the left corner of the mouth, and was fixed with the head slightly inclined to the operator by approximately 10°. The headband reference frame was fixed to the head, the neuronavigation system was registered, and its accuracy was confirmed. Iodophors were routinely used to disinfect the skin of the face, nasal cavity, and right thigh, and sterile drapes were applied. Using adrenaline cotton pledgets, the bilateral nasal mucosa was contracted along the middle turbinate and nasal septal channels for 5 min. A right nasal septum pedicled mucosal flap was routinely prepared for patients in whom the risk of CSF leakage was judged to be high before the operation. The opening position of the sphenoid sinus was determined, mucosa was removed, and bone of the anterior wall of the sphenoid sinus was drilled using a high-speed drill to expand the operating space. At the same time, the posterior and lower part of the bony nasal septum was drilled and the mucosa was opened at the back of the contralateral nasal cavity. Surgery was mainly performed using the binostril four-hand technique, and the tumors in the sphenoid sinus cavity and clivus were gradually removed to expose the important structures such as the sphenoid planum, optic canal, tuberculum sellae, and ICA, while avoiding intraoperative injury. During the operation, combined with the neuronavigation fusion image, important structures including the basilar artery and ICA were accurately identified (Fig. 2 ). Neuronavigation enabled immediate identification of the ICA and its relationship with the tumor. When the tumor had grown into the posterior cranial fossa, it was separated from the brainstem, interpeduncular cistern, prepontine cistern, vertebral artery, cranial nerves, and other important structures. The skull base was reconstructed with multiple layers of materials (autologous fat tissue, artificial dura, autologous fascia lata covered onlay, pedicled nasoseptal flap, biological protein glue, and urinary catheter balloon, etc.). If CSF leakage occurred during the surgery, lumbar cistern drainage was routinely performed. Postoperative Management All patients underwent head CT on the second day after surgery, and MRI was performed to assess the extent of resection. GTR or STR was classified based on pre- and postoperative MRI scans. The patients were monitored for diabetes insipidus, electrolyte disorders, abnormal body temperature, level of consciousness, mental symptoms, vision, cranial nerve function, and cerebrospinal fluid rhinorrhea. Gamma-knife treatment was recommended for patients with residual tumor after surgery. Results Twelve patients were reviewed for intraoperative findings, surgical outcomes, and follow-up data (Table 2 ). GTR was achieved in 66.67% (8 cases) and STR in 33.33% (4 cases). During the operation, six patients had tumors with a soft or jelly-like texture, which could be easily removed by suction. Two patients had tumors that were slightly tough and adhered to the brainstem. The remaining four cases had a tough texture with abundant blood supply and adhered to the paraclival ICA; therefore, only STR was achieved in these cases. Table 2 Treatment and outcome summary for chordoma patients Patient no. Resection operation time (minutes) skull base reconstruction complications recurrence Add treatment number of operations CSF leaks (after operation) CSF leaks (during operation) 1 GTR 120 artificial dura and the pedicled nasoseptal flap none none none 1 none none 2 GTR 125 autologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap none none none 1 none CSF leaks 3 GTR 140 autologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap none none none 1 none CSF leaks 4 GTR 145 artificial dura and the pedicled nasoseptal flap none none none 1 none none 5 GTR 155 artificial dura and the pedicled nasoseptal flap none none none 1 none none 6 GTR 165 artificial dura and the pedicled nasoseptal flap none none none 1 none none 7 STR 175 artificial dura and the pedicled nasoseptal flap none remain static radiotherapy 1 none none 8 STR 185 artificial dura and the pedicled nasoseptal flap none remain static radiotherapy 1 none none 9 STR 200 autologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap none remain static radiotherapy 1 none CSF leaks 10 GTR 110 autologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap none none none 1 none CSF leaks 11 STR 360 autologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap oculomotor paralysis remain static radiotherapy 1 none CSF leaks 12 GTR 60 artificial dura and the pedicled nasoseptal flap none none none 1 none none Regarding CSF leakage, two patients presented with preoperative CSF leakage, and five patients experienced intraoperative CSF leakage when the tumor broke through the dura and invaded the posterior cranial fossa (Table 2 ). For these patients, the skull base was reconstructed strictly using multiple layers, including autologous fat tissue, artificial dura, autologous fascia lata covered onlay, pedicled nasoseptal flap, biological protein glue, and urinary catheter balloon. Lumbar cistern drainage was performed postoperatively. No CSF leakage or intracranial infection was observed after surgery. Two patients with blepharoptosis gradually recovered after surgery. One patient (Case 11) developed transient oculomotor paralysis postoperatively. The postoperative hospital stay was approximately 5–12 days, and all cases were pathologically diagnosed as chordoma. Ten patients were followed for 40–59 months after the operation. The symptoms of headache, nasal obstruction, dizziness, and diplopia significantly improved compared with preoperative status. There were no occurrences of intracranial hemorrhage, postoperative CSF leakage, intracranial infection, or death. The four patients who underwent subtotal resection received proton radiation therapy, and no obvious tumor growth or recurrence was observed during follow-up. Discussions Chordomas occurring in the clivus of the skull base account for 0.1% − 0.7% of intracranial tumors [ 6 , 7 ] . The clivus chordoma of the skull base is typically located on the ventral side of the dura mater. It can invade the parasellar or suprasellar region and extend into the skull, nasal cavity, and posterior pharyngeal wall. It can also invade the posterior cranial fossa, involve the cerebellopontine angle, or even compress the brainstem. Most patients have chronic symptoms that last for months to years. The clinical signs and symptoms have no obvious specific manifestations, and headache is the most common symptom. In our series, the manifestations included simple headache in 3 cases and dizziness in 2 cases. Clinical manifestations are closely related to the tumor size, position, and direction of invasion. CT and MRI are important imaging modalities for the preoperative diagnosis of skull base clivus chordoma [ 8 ] . However, imaging findings are similar to other space-occupying lesions of the skull base clivus, such as nasopharyngeal carcinoma, pituitary adenoma, and chondroma, and diagnosis often relies on postoperative histopathological examination [ 3 , 6 ] . Surgery is the primary treatment for chordoma of the skull base clivus. Complete resection along the tumor boundary is the optimal surgical approach. For patients in whom tumors cannot be completely resected, combined postoperative radiotherapy can also effectively improve the prognosis and delay the recurrence [ 2 , 7 , 9 , 10 ] . Because of the deep position within the skull base, chordomas can cause severe clinical symptoms and show extensive invasion into the skull base, cavernous sinus, paranasal sinus, pterygopalatine fossa, infratemporal fossa, oropharynx, and involve important nerves and vessels, which makes total resection more difficult [ 4 , 11 , 12 ] . The application of EES has improved the GTR rate for skull base clivus chordoma [ 9 , 13 ] . With the increasing number of publications reporting on EES for skull base chordomas, the GTR rate ranges from 33% to 86% [ 11 ] .Bai J et. [ 9 ] had reported 284 cases of clival chordomas about 74.6% of tumors were marginally resected,while Essayed WI et. [ 5 ] reported that the average extent of resection reached 97.7% with multimodal intraoperative image-driven surgery. In our series of 12 cases, GTR was achieved in 66.67% and STR in 33.33%. The use of neuronavigation may have contributed to this relatively favorable GTR rate by enabling real-time identification of critical structures during surgery. The tumor size, blood supply, texture, radiotherapy history, relationship with adjacent nerves and vessels, and invasion range of skull base clivus chordomas are often important factors that determine the difficulty of the operation and affect the total resection rate [ 2 , 9 , 13 , 15 ] . In our series, 4 cases failed to achieve GTR because the tumors had invaded the cavernous sinus, pterygopalatine fossa, and infratemporal fossa. When the tumor invades the ICA or basilar artery, there is risk of vascular injury and massive bleeding [ 16 , 17 ] . These four cases had tumors with tough texture, rich blood supply, and obvious adhesion to the paraclival ICA, which led to residual tumor (Fig. 2 ). After surgery, these patients received adjuvant radiotherapy. Dynamic follow-up re-examination showed that the tumors were well controlled. For complex skull base clivus chordoma, adequate preoperative evaluation is important to improve the efficacy and safety of surgery and to choose the appropriate surgical approach [ 13 ] . Neuroendoscopy provides an ultra-high-definition surgical field of vision [ 5 , 14 ] , enabling close observation with a wide exposure range and minimal blind spots. With the neuronavigation system, we can identify tumor resection extent and its relationship with surrounding structures, especially the ICA and vertebrobasilar artery [ 14 ] , even when the tumor surrounds the ICA(Fig. 2 ). Moreover,we suggest routine cerebral angiography and balloon occlusion tests to identify compensation of the ICA on both sides and the anterior and posterior circulation. There was no obvious injury to important nerves and vessels in this group of cases. In the past, the neuronavigation system was prone to intraoperative displacement, with navigation data deviation and other problems. However, the navigation is now more accurate and reliable. These problems no longer bother us. CSF leakage and cranial nerve injury have been the main complications reported in prior studies [ 4 , 9 , 11 , 13 , 16 ] . In our series, two patients presented with CSF leakage before surgery and five patients developed CSF leakage during surgery. The skull base was repaired using multi-layer reconstruction techniques, including autologous fat tissue, artificial dura, autologous fascia lata-covered onlay, pedicled nasoseptal flap, biological protein glue, and urinary catheter balloon [ 18 ] . No postoperative cerebrospinal fluid leakage or new cranial nerve dysfunction was observed. This study has several limitations. First, the sample size is relatively small (n = 12), which limits the generalizability of our findings. Second, as a retrospective single-center study without a control group, we cannot definitively compare outcomes with or without neuronavigation. Third, longer follow-up is needed to assess long-term recurrence rates. Despite these limitations, our results suggest that neuronavigation-assisted EES is a viable approach for skull base chordomas. Conclusions In this consecutive series of 12 patients with skull base chordomas, neuronavigation-assisted EES achieved a GTR rate of 66.67% with no major postoperative complications. Neuronavigation enables real-time identification of critical neurovascular structures, particularly the ICA and basilar artery, which enhances surgical safety and facilitates tumor resection. Combined with multilayer skull base reconstruction techniques, this approach effectively minimizes postoperative CSF leakage. Although limited by the small sample size, our results suggest that neuronavigation-assisted EES is a safe and effective approach for the treatment of skull base chordomas. Patients with subtotal resection may benefit from adjuvant radiotherapy to achieve tumor control. Abbreviations EES,endoscopic endonasal surgery;ICA,Internal Carotid Artery; CSF,cerebrospinal fluid; GTR,Gross total resection;STR,subtotal resection;MRI,magnetic resonance imaging. Declarations Ethics Statement Clinical trial is not applicable. The need for further ethical approval was waived by the Ganzhou People's Hospital Research Committee owing to the retrospective nature of the study. This study was conducted in strict accordance with the principles of the Declaration of Helsinki. Patient consent was obtained from the patients，if the patients were children, the patient consent was obtained from the patients and guardian of patients in this study, including for the individual case details in Table 1. Ethics approval and consent to participate This study was approved by the Research Ethics Committee of Ganzhou People's Hospital (Approval No. 2022-012, dated March 10, 2022). Due to the retrospective nature of the study, the requirement for additional informed consent was waived by the committee. This study was conducted in strict accordance with the principles of the Declaration of Helsinki. Consent to participate Written informed consent was obtained from all individual participants included in this study. For participants under the age of 18, consent was obtained from both the participant and their legal guardian. Consent for publication Not applicable. Availability of data and material All data generated or analysed during this study are included in this published article. Competing interests The authors declare that they have no competing interests. Funding This study was funded by the Project of Science and Technology Plan of Ganzhou Science and Technology Bureau (GSKF [2019] No. 60), Jiangxi Provincial Health Commission Science and Technology Plan Project (SKJP202218028), and Jiangxi Province High-Level and High-Skilled Leading Talents Project Training Project (2021). Authors' contributions YXY and JQH conceived and designed the study. HGL and LWT collected the data and performed data analyses. All authors contributed to the interpretation of the data and completion of the figures and tables. All authors contributed to the drafting of the manuscript and the final approval of the submitted version. Acknowledgements Not available. References Lanzino G, Dumont AS, Lopes MB, Laws ER Jr. Skull base chordomas: overview of disease, management options, and outcome. Neurosurg Focus. 2001;10(3):E12. Ito E, Saito K, Okada T, Nagatani T, Nagasaka T. Long-term control of clival chordoma with initial aggressive surgical resection and gamma knife radiosurgery for recurrence. Acta Neurochir (Wien). 2010;152(1):57–67. discussion 67. Fernandez-Miranda JC, Gardner PA, Snyderman CH, et al. Clival chordomas: A pathological, surgical, and radiotherapeutic review. Head Neck. 2014;36(6):892–906. Ceylan S, Emengen A, Caklili M, et al. Operative nuances and surgical limits of the endoscopic approach to clival chordomas and chondrosarcomas: A single-center experience of 72 patients. Clin Neurol Neurosurg. 2021;208:106875. Essayed WI, Juvekar P, Bernstock JD et al. Multimodal Intraoperative Image-Driven Surgery for Skull Base Chordomas and Chondrosarcomas. Cancers (Basel). 2022. 14(4). Frezza AM, Botta L, Trama A, Dei Tos AP, Stacchiotti S. Chordoma: update on disease, epidemiology, biology and medical therapies. Curr Opin Oncol. 2019;31(2):114–20. McMaster ML, Goldstein AM, Bromley CM, Ishibe N, Parry DM. Chordoma: incidence and survival patterns in the United States, 1973–1995. Cancer Causes Control. 2001;12(1):1–11. Tempany CM, Jayender J, Kapur T, et al. Multimodal imaging for improved diagnosis and treatment of cancers. Cancer. 2015;121(6):817–27. Bai J, Li M, Shi J, et al. Mid-term follow-up surgical results in 284 cases of clival chordomas: the risk factors for outcome and tumor recurrence. Neurosurg Rev. 2022;45(2):1451–62. Metcalfe C, Muzaffar J, Kulendra K, et al. Chordomas and chondrosarcomas of the skull base: treatment and outcome analysis in a consecutive case series of 24 patients. World J Surg Oncol. 2021;19(1):68. Wang B, Li Q, Sun Y, Tong X. Surgical Strategy for Skull Base Chordomas: Transnasal Midline Approach or Transcranial Lateral Approach. J Korean Neurosurg Soc. 2022. Patra DP, Hess RA, Turcotte EL, et al. Surgical Outcomes with Midline versus Lateral Approaches for Cranial Base Chordomas: A Systematic Review and Meta-Analysis. World Neurosurg. 2020;140:378–e3882. Bai J, Li M, Xiong Y, et al. Endoscopic Endonasal Surgical Strategy for Skull Base Chordomas Based on Tumor Growth Directions: Surgical Outcomes of 167 Patients During 3 Years. Front Oncol. 2021;11:724972. Essayed W, Mooney MA, Al-Mefty O. Transcavernous Resection of an Upper Clival Chondrosarcoma: Cavernous Sinus as a Route: 2-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2021. 20(6): E422–3. Kim YH, Jeon C, Se YB, et al. Clinical outcomes of an endoscopic transclival and transpetrosal approach for primary skull base malignancies involving the clivus. J Neurosurg. 2018;128(5):1454–62. Koutourousiou M, Gardner PA, Tormenti MJ et al. Endoscopic endonasal approach for resection of cranial base chordomas: outcomes and learning curve. Neurosurgery. 2012. 71(3): 614 – 24; discussion 624-5. Zhang Y, Tian Z, Li C, et al. A modified endovascular treatment protocol for iatrogenic internal carotid artery injuries following endoscopic endonasal surgery. J Neurosurg. 2019;132(2):343–50. Champagne PO, Zenonos GA, Wang EW, Snyderman CH, Gardner PA. The rhinopharyngeal flap for reconstruction of lower clival and craniovertebral junction defects. J Neurosurg. 2021: 1–9. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 11 Mar, 2026 Reviews received at journal 11 Mar, 2026 Reviewers agreed at journal 05 Mar, 2026 Reviews received at journal 04 Mar, 2026 Reviewers agreed at journal 01 Mar, 2026 Reviewers agreed at journal 28 Feb, 2026 Reviewers invited by journal 27 Feb, 2026 Editor invited by journal 26 Feb, 2026 Editor assigned by journal 26 Feb, 2026 Submission checks completed at journal 26 Feb, 2026 First submitted to journal 24 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {\"props\":{\"pageProps\":{\"initialData\":{\"identity\":\"rs-8954762\",\"acceptedTermsAndConditions\":true,\"allowDirectSubmit\":false,\"archivedVersions\":[],\"articleType\":\"Research Article\",\"associatedPublications\":[],\"authors\":[{\"id\":598921713,\"identity\":\"226c7ddf-c428-4602-9562-7eb115d8eaed\",\"order_by\":0,\"name\":\"Guanlin Huang\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Ganzhou People’s Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Guanlin\",\"middleName\":\"\",\"lastName\":\"Huang\",\"suffix\":\"\"},{\"id\":598921718,\"identity\":\"8e60f66d-5f9a-46d8-b938-9c3f3e609b26\",\"order_by\":1,\"name\":\"Qiuhua Jiang\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Ganzhou People’s Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Qiuhua\",\"middleName\":\"\",\"lastName\":\"Jiang\",\"suffix\":\"\"},{\"id\":598921724,\"identity\":\"ca9c5b43-d6e7-4189-b464-7b8c9e935ce3\",\"order_by\":2,\"name\":\"Wentao Lai\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Ganzhou People’s Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Wentao\",\"middleName\":\"\",\"lastName\":\"Lai\",\"suffix\":\"\"},{\"id\":598921726,\"identity\":\"5ea8bcb4-46b4-4a82-bc27-6b52853804db\",\"order_by\":3,\"name\":\"Xiaoping Zhou\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Ganzhou People’s Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Xiaoping\",\"middleName\":\"\",\"lastName\":\"Zhou\",\"suffix\":\"\"},{\"id\":598921727,\"identity\":\"119942d9-0852-4094-b2c4-e739d2dd2c0f\",\"order_by\":4,\"name\":\"Qi Zhong\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Ganzhou People’s Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Qi\",\"middleName\":\"\",\"lastName\":\"Zhong\",\"suffix\":\"\"},{\"id\":598921728,\"identity\":\"9ed53b9f-5ff4-4645-aeba-a1d575ecce8d\",\"order_by\":5,\"name\":\"Yuqing Liao\",\"email\":\"\",\"orcid\":\"\",\"institution\":\"Ganzhou People’s Hospital\",\"correspondingAuthor\":false,\"prefix\":\"\",\"firstName\":\"Yuqing\",\"middleName\":\"\",\"lastName\":\"Liao\",\"suffix\":\"\"},{\"id\":598921729,\"identity\":\"9a9e43e8-3f2d-4f63-8d7b-b52d8c79061c\",\"order_by\":6,\"name\":\"Xinyun Ye\",\"email\":\"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAsUlEQVRIiWNgGAWjYNCCiho5Nvb2A6RoOXPMmI/nTAIJOhjbmBPnSTgYEKeav7354eeCM2zpbRIMCQw/KrYR1iIBdJP0jAqZ3DbpxgOMPWduE9ZiIJHDIM1zhi23TeZAAjNjGzFa5N8w/+ZtY05nk0gwIFKLBA+bNFBLAvFaJM6kmVnznDlm2AYM5INE+YW//fDj2zwVNfLy7e0HH/yoIEILCjhAovpRMApGwSgYBbgAANwLNzfpIXlyAAAAAElFTkSuQmCC\",\"orcid\":\"\",\"institution\":\"Ganzhou People’s Hospital\",\"correspondingAuthor\":true,\"prefix\":\"\",\"firstName\":\"Xinyun\",\"middleName\":\"\",\"lastName\":\"Ye\",\"suffix\":\"\"}],\"badges\":[],\"createdAt\":\"2026-02-24 08:38:24\",\"currentVersionCode\":1,\"declarations\":\"\",\"doi\":\"10.21203/rs.3.rs-8954762/v1\",\"doiUrl\":\"https://doi.org/10.21203/rs.3.rs-8954762/v1\",\"draftVersion\":[],\"editorialEvents\":[],\"editorialNote\":\"\",\"failedWorkflow\":false,\"files\":[{\"id\":104176175,\"identity\":\"6805e570-7208-420a-8586-ea757d3cda61\",\"added_by\":\"auto\",\"created_at\":\"2026-03-08 16:36:27\",\"extension\":\"png\",\"order_by\":1,\"title\":\"Figure 1\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":1204613,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eThe patient was an elderly female suffered from head pain with visual double shadow, ptosis and dysphagia more than 9 months. A. Preoperative cranial CT showed a mass of low-density shadow in sellar region, clivus and anterior pontine cistern, with unclear boundary, and most of the clivus bone was destroyed; B ~ E. preoperative cranial MRI showed abnormal signals of long T1 (B), long T2 (C, D) with irregular oval shape in sellar region, clivus and anterior pontine cistern. There was partial mild enhancement (E) on enhanced scanning. The clivus bone was destroyed by tumors,and tumors adhered to the midbrain,anterior pontine, the internal carotid arteries and basilar arteries; F ~ G. Bilateral internal carotid artery, basilar artery and abducent nerve exposed after tumor resection during operation; H. Postperative MRI showed that the tumor was completely removed (the enhanced part was filled with fat), the compression of brain stem was relieved, and the mucosal flap grew well; I. The typical chordoma conformation (HE staining) was observed by postoperative pathological examination × 40).\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"1.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-8954762/v1/b27e26ae14587243869ae6c0.png\"},{\"id\":104404573,\"identity\":\"459ad964-4f18-4f68-a35a-406fe0e85603\",\"added_by\":\"auto\",\"created_at\":\"2026-03-11 12:20:32\",\"extension\":\"png\",\"order_by\":2,\"title\":\"Figure 2\",\"display\":\"\",\"copyAsset\":false,\"role\":\"figure\",\"size\":516813,\"visible\":true,\"origin\":\"\",\"legend\":\"\\u003cp\\u003eThe patient was an teenager suffered from rhinobyon about 1 year. A. Preoperative cranial CT showed a mass of low-density shadow in sphenoid sinus, ethmoid sinus,turbinate,clivus, middle cranial fossa,posterior fossa,pterygopalatine fossa and infratemporal fossa, cavernous sinus, with unclear boundary, and most of the clivus bone was destroyed; B ~ F.Preoperative cranial MRI showed abnormal signals of long T2 (B,C),with irregular oval shape in broad region. There was strong enhancement (D,E,F) on enhanced scanning. The clivus bone was destroyed by tumors,and tumors adhered to the middle cranial fossa,posterior fossa,pterygopalatine fossa and infratemporal fossa, cavernous sinus, the internal carotid arteries and basilar arteries,ect; G ~ I.Preoperative BOT tests N,O.Shows neuronavigation during opreation.P~S.Right internal carotid artery exposed after tumor resection during operation,the yellow arrows point to the right internal carotid artery,the blue asterisks point to tumor,the green arrow points to the dura of posterior fossa; J~L. Postperative MRI showed that the tumor was subtotal removed, the compression of brain stem was relieved, and the mucosal flap grew well;M. The typical chordoma conformation (HE staining) was observed by postoperative pathological examination × 40).\\u003c/p\\u003e\",\"description\":\"\",\"filename\":\"2.png\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-8954762/v1/4f2ea155986cfb94904513e6.png\"},{\"id\":104779564,\"identity\":\"39cf1b46-853f-470d-a28e-e79afefac5e8\",\"added_by\":\"auto\",\"created_at\":\"2026-03-17 07:42:20\",\"extension\":\"pdf\",\"order_by\":0,\"title\":\"\",\"display\":\"\",\"copyAsset\":false,\"role\":\"manuscript-pdf\",\"size\":3785195,\"visible\":true,\"origin\":\"\",\"legend\":\"\",\"description\":\"\",\"filename\":\"manuscript.pdf\",\"url\":\"https://assets-eu.researchsquare.com/files/rs-8954762/v1/9b79d84a-33a8-48e0-83f9-224f41675289.pdf\"}],\"financialInterests\":\"No competing interests reported.\",\"formattedTitle\":\"\\u003cp\\u003eNeuronavigation assisted Endoscopic Endonasal Surgery for Skull Base Chordomas: treatment and outcome analysis in a consecutive case series of 12 patients\\u003c/p\\u003e\",\"fulltext\":[{\"header\":\"Introduction\",\"content\":\"\\u003cp\\u003eChordomas are bone tumors that originate from the primitive notochord along the spinal axis, and the two ends of the vertebral axis \\u0026mdash; sacrococcygeal and clival regions \\u0026mdash; are the most common sites \\u003csup\\u003e[\\u003cspan citationid=\\\"CR1\\\" class=\\\"CitationRef\\\"\\u003e1\\u003c/span\\u003e]\\u003c/sup\\u003e. Clival chordomas are aggressive, pathologically low-grade malignant tumors and usually exhibit midline presentation. Surgical resection is the first choice for skull base clivus chordomas, and the degree of surgical resection is highly correlated with the prognosis\\u003csup\\u003e[\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e]\\u003c/sup\\u003e. These tumors are located deeply, adjacent to important nerves and blood vessels, and they invade widely. Therefore, total resection is difficult and the postoperative recurrence rate is high\\u003csup\\u003e[\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e]\\u003c/sup\\u003e. With the rapid development of imaging, neuronavigation and endoscopy, these technologies provide good technical support for improving the total resection rate of skull base clivus chordomas\\u003csup\\u003e[\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e]\\u003c/sup\\u003e. We retrospectively analyzed 12 patients with skull base chordomas in the Department of Neurosurgery of Ganzhou People's Hospital from May 2018 to April 2020.\\u003c/p\\u003e\"},{\"header\":\"Patients and Methods\",\"content\":\"\\u003cdiv id=\\\"Sec3\\\" class=\\\"Section2\\\"\\u003e \\u003ch2\\u003ePatient Data\\u003c/h2\\u003e \\u003cp\\u003eWe retrospectively analyzed 12 patients with skull base chordomas in the Department of Neurosurgery at Ganzhou People's Hospital between May 2018 and April 2020. All 12 patients were reviewed for age, sex, presenting symptoms, preoperative physical examination findings, and imaging findings (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e).\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab1\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 1\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eclinical and tumor characteristics of skull base chordoma patients\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"8\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"char\\\" char=\\\"\\u0026times;\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c5\\\" colnum=\\\"5\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c6\\\" colnum=\\\"6\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c7\\\" colnum=\\\"7\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"char\\\" char=\\\".\\\" class=\\\"colspec\\\" colname=\\\"c8\\\" colnum=\\\"8\\\"\\u003e\\u003c/div\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003ePatient\\u003c/p\\u003e \\u003cp\\u003eno.\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eSymptoms\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003ePhysical examination\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eTumor dimensions\\u003c/p\\u003e \\u003cp\\u003e(mm)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eLocation\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eenhanced MRI\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003esoft group or firm group\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003ecourse of disease\\u003c/p\\u003e \\u003cp\\u003e(days)\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003ediplopia\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003ediplopia\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e30.6\\u0026times;28.8\\u0026times;28.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eUpper-middle clivus\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eNo enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003esoft\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e30\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eCSF leakage\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eCSF leakage\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e30.3\\u0026times;34.4\\u0026times;22.5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus,Upper-middle clivus,interpeduncular cistern,the prepontine cistern\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eNo enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003esoft\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e4\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e3\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache with double vision, blepharoptosis and dysphagia\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003edouble vision, blepharoptosis and dysphagia\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e28.8\\u0026times;38.4\\u0026times;34.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus,Upper-middle clivus,interpeduncular cistern,the prepontine cistern\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eslightly enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003esoft\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e270\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e4\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache and dizziness\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e26.7\\u0026times;25.4\\u0026times;29.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus,Upper-middle clivus,right Cavernous sinus\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003emoderate enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003esoft\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e7\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache and dizziness\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e36.0\\u0026times;32.4\\u0026times;50.4\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus,Upper-middle\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003emoderate enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003esoft\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e14\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e6\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e37.8\\u0026times;48.2\\u0026times;34.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus,Upper-middle clivus,interpeduncular cistern,the prepontine cistern\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003estrong enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003efirm\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e30\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e7\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e54.3\\u0026times;46.6\\u0026times;29.5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus,Ethmoid sinus,Upper-middle clivus,right Cavernous sinus\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003estrong enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003efirm\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e60\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e8\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eFacial pain and swelling\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e39.6\\u0026times;48.3\\u0026times;41.5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003emaxillary sinus, pterygopalatine fossa and infratemporal fossa\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003estrong enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003efirm\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e180\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e9\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache with blepharoptosis and dysphagia\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eblepharoptosis and dysphagia\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e46.1\\u0026times;54.7\\u0026times;56.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus, whole clivus,pterygopalatine fossa and infratemporal fossa,right Cavernous sinus\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003estrong enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003efirm\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e30\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e10\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache with CSF leakage\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eCSF leakage\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e24.6\\u0026times;19.2\\u0026times;37.5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus,Upper-middle clivus\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eNo enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003esoft\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e12\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e11\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003erhinobyon\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003erhinobyon\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e84\\u0026times;78\\u0026times;82\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003esphenoid sinus, ethmoid sinus, turbinate,whole clivus, middle cranial fossa, posterior fossa,pterygopalatine fossa and infratemporal fossa, Cavernous sinus\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003estrong enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003efirm\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e365\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e12\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eHeadache\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\"\\u0026times;\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003e26.6\\u0026times;31.4\\u0026times;30.2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eUpper-middle clivus\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003emoderate enhancement\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003efirm\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e60\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003c/div\\u003e\\n\\u003ch3\\u003eImaging Data\\u003c/h3\\u003e\\n\\u003cp\\u003eAll patients underwent both CT and MRI of the nasopharynx and skull base before surgery. On CT, most of the bone destruction in the clivus could be observed, and the bone destruction area was replaced by a soft tissue mass. The boundary between the tumor and normal bone was unclear. Residual bone fragments and patchy calcifications could be observed in the lesion, or the tumor had invaded the surrounding anatomical spaces. Intracranial pneumatosis was observed in 2 patients with cerebrospinal fluid leakage (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig1\\\" class=\\\"InternalRef\\\"\\u003e1\\u003c/span\\u003e). On MRI, most of the tumors showed T1 equal or slightly low signal, and a few lesions showed spotty and flaky high signal; T2 showed mostly high signal, with scattered low signal within. Regarding enhancement patterns, three cases showed no obvious enhancement, one case showed slight enhancement, three cases showed moderate enhancement, and five cases showed obvious enhancement. The tumors of all 12 patients were located in the midline of the skull base or extended to both sides, including the following distributions: two in the middle and upper clivus; three in the sphenoid sinus and middle and upper clivus; three in the sphenoid sinus, middle and upper clivus, interpeduncular cistern, and prepontine cistern; one in the sphenoid sinus, ethmoid sinus, middle and upper clivus, and right cavernous sinus; one in the sphenoid sinus, upper, middle, and lower clivus, right cavernous sinus, pterygopalatine fossa and infratemporal fossa; and one that invaded the sphenoid sinus, maxillary sinus, and pterygopalatine fossa. The tumors extended to the left and right spaces of cavernous ICA or paraclival and lacerum ICA, measuring approximately 6.51\\u0026ndash;26.17 mm in width and 13.36\\u0026ndash;43.37 mm in length, and extended to the dorsum sellae and posterior clinoid process region, measuring approximately 22.53\\u0026ndash;56.18 mm superoinferiorly and 19.23\\u0026ndash;54.74 mm anteroposteriorly.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e\\n\\u003ch3\\u003eSurgical Technique\\u003c/h3\\u003e\\n\\u003cp\\u003eAll patients underwent endoscopic endonasal transclival surgery with the neuronavigation system. Preoperative examinations and preparations included: ⑴pituitary hormone, thyroid hormone and cortisol levels; (2) visual acuity, visual field and fundus examination; (3) CT examination; (4) MRI scanning; (5) neuronavigation data preparation: CT and MR image data were fused into the neuronavigation system before the operation, followed by image fusion and 3D reconstruction; (6) preoperative nasal irrigation.\\u003c/p\\u003e \\u003cp\\u003eThe main equipment used during the operation included: German Karl Storz supporting instruments and ultra-high definition neuroendoscope system, 4 mm diameter endoscope (0\\u0026deg; and 45\\u0026deg;), video acquisition system, and display from Karl Storz company; Medtronic high-speed grinding and drilling system; and German BrainLAB neuronavigation system and its accessories. We mainly performed EES using the binostril four-hand technique, and the three surgeons' five-hand technique was used when necessary.\\u003c/p\\u003e \\u003cp\\u003eThe main operation steps were as follows: The patient underwent general anesthesia with endotracheal intubation, was placed in the supine position, the dental pad was removed, the endotracheal tube was moved to the left corner of the mouth, and was fixed with the head slightly inclined to the operator by approximately 10\\u0026deg;. The headband reference frame was fixed to the head, the neuronavigation system was registered, and its accuracy was confirmed. Iodophors were routinely used to disinfect the skin of the face, nasal cavity, and right thigh, and sterile drapes were applied. Using adrenaline cotton pledgets, the bilateral nasal mucosa was contracted along the middle turbinate and nasal septal channels for 5 min. A right nasal septum pedicled mucosal flap was routinely prepared for patients in whom the risk of CSF leakage was judged to be high before the operation. The opening position of the sphenoid sinus was determined, mucosa was removed, and bone of the anterior wall of the sphenoid sinus was drilled using a high-speed drill to expand the operating space. At the same time, the posterior and lower part of the bony nasal septum was drilled and the mucosa was opened at the back of the contralateral nasal cavity. Surgery was mainly performed using the binostril four-hand technique, and the tumors in the sphenoid sinus cavity and clivus were gradually removed to expose the important structures such as the sphenoid planum, optic canal, tuberculum sellae, and ICA, while avoiding intraoperative injury. During the operation, combined with the neuronavigation fusion image, important structures including the basilar artery and ICA were accurately identified (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). Neuronavigation enabled immediate identification of the ICA and its relationship with the tumor. When the tumor had grown into the posterior cranial fossa, it was separated from the brainstem, interpeduncular cistern, prepontine cistern, vertebral artery, cranial nerves, and other important structures. The skull base was reconstructed with multiple layers of materials (autologous fat tissue, artificial dura, autologous fascia lata covered onlay, pedicled nasoseptal flap, biological protein glue, and urinary catheter balloon, etc.). If CSF leakage occurred during the surgery, lumbar cistern drainage was routinely performed.\\u003c/p\\u003e \\u003cp\\u003e \\u003c/p\\u003e\\n\\u003ch3\\u003ePostoperative Management\\u003c/h3\\u003e\\n\\u003cp\\u003eAll patients underwent head CT on the second day after surgery, and MRI was performed to assess the extent of resection. GTR or STR was classified based on pre- and postoperative MRI scans. The patients were monitored for diabetes insipidus, electrolyte disorders, abnormal body temperature, level of consciousness, mental symptoms, vision, cranial nerve function, and cerebrospinal fluid rhinorrhea. Gamma-knife treatment was recommended for patients with residual tumor after surgery.\\u003c/p\\u003e\"},{\"header\":\"Results\",\"content\":\"\\u003cp\\u003eTwelve patients were reviewed for intraoperative findings, surgical outcomes, and follow-up data (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). GTR was achieved in 66.67% (8 cases) and STR in 33.33% (4 cases). During the operation, six patients had tumors with a soft or jelly-like texture, which could be easily removed by suction. Two patients had tumors that were slightly tough and adhered to the brainstem. The remaining four cases had a tough texture with abundant blood supply and adhered to the paraclival ICA; therefore, only STR was achieved in these cases.\\u003c/p\\u003e \\u003cp\\u003e \\u003cdiv class=\\\"gridtable\\\"\\u003e\\u003ctable float=\\\"Yes\\\" id=\\\"Tab2\\\" border=\\\"1\\\"\\u003e \\u003ccaption language=\\\"En\\\"\\u003e \\u003cdiv class=\\\"CaptionNumber\\\"\\u003eTable 2\\u003c/div\\u003e \\u003cdiv class=\\\"CaptionContent\\\"\\u003e \\u003cp\\u003eTreatment and outcome summary for chordoma patients\\u003c/p\\u003e \\u003c/div\\u003e \\u003c/caption\\u003e \\u003ccolgroup cols=\\\"10\\\"\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c1\\\" colnum=\\\"1\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c2\\\" colnum=\\\"2\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"char\\\" char=\\\".\\\" class=\\\"colspec\\\" colname=\\\"c3\\\" colnum=\\\"3\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c4\\\" colnum=\\\"4\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c5\\\" colnum=\\\"5\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c6\\\" colnum=\\\"6\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c7\\\" colnum=\\\"7\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"char\\\" char=\\\".\\\" class=\\\"colspec\\\" colname=\\\"c8\\\" colnum=\\\"8\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c9\\\" colnum=\\\"9\\\"\\u003e\\u003c/div\\u003e \\u003cdiv align=\\\"left\\\" class=\\\"colspec\\\" colname=\\\"c10\\\" colnum=\\\"10\\\"\\u003e\\u003c/div\\u003e \\u003cthead\\u003e \\u003ctr\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003ePatient\\u003c/p\\u003e \\u003cp\\u003eno.\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eResection\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003eoperation time\\u003c/p\\u003e \\u003cp\\u003e(minutes)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eskull base reconstruction\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003ecomplications\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003erecurrence\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eAdd treatment\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003enumber of operations\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003eCSF leaks\\u003c/p\\u003e \\u003cp\\u003e(after operation)\\u003c/p\\u003e \\u003c/th\\u003e \\u003cth align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003eCSF leaks\\u003c/p\\u003e \\u003cp\\u003e(during operation)\\u003c/p\\u003e \\u003c/th\\u003e \\u003c/tr\\u003e \\u003c/thead\\u003e \\u003ctbody\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e120\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eartificial dura and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e2\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e125\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eautologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003eCSF leaks\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e3\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e140\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eautologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003eCSF leaks\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e4\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e145\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eartificial dura and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e5\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e155\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eartificial dura and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e6\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e165\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eartificial dura and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e7\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eSTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e175\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eartificial dura and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eremain static\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eradiotherapy\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e8\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eSTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e185\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eartificial dura and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eremain static\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eradiotherapy\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e9\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eSTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e200\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eautologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eremain static\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eradiotherapy\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003eCSF leaks\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e10\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e110\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eautologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003eCSF leaks\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e11\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eSTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e360\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eautologous fat tissue, artificial dura, autologous fascia lata covered onlay and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003eoculomotor paralysis\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003eremain static\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003eradiotherapy\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003eCSF leaks\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003ctr\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c1\\\"\\u003e \\u003cp\\u003e12\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c2\\\"\\u003e \\u003cp\\u003eGTR\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c3\\\"\\u003e \\u003cp\\u003e60\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c4\\\"\\u003e \\u003cp\\u003eartificial dura and the pedicled nasoseptal flap\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c5\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c6\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c7\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"char\\\" char=\\\".\\\" colname=\\\"c8\\\"\\u003e \\u003cp\\u003e1\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c9\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003ctd align=\\\"left\\\" colname=\\\"c10\\\"\\u003e \\u003cp\\u003enone\\u003c/p\\u003e \\u003c/td\\u003e \\u003c/tr\\u003e \\u003c/tbody\\u003e \\u003c/colgroup\\u003e \\u003c/table\\u003e\\u003c/div\\u003e \\u003c/p\\u003e \\u003cp\\u003eRegarding CSF leakage, two patients presented with preoperative CSF leakage, and five patients experienced intraoperative CSF leakage when the tumor broke through the dura and invaded the posterior cranial fossa (Table\\u0026nbsp;\\u003cspan refid=\\\"Tab2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). For these patients, the skull base was reconstructed strictly using multiple layers, including autologous fat tissue, artificial dura, autologous fascia lata covered onlay, pedicled nasoseptal flap, biological protein glue, and urinary catheter balloon. Lumbar cistern drainage was performed postoperatively. No CSF leakage or intracranial infection was observed after surgery.\\u003c/p\\u003e \\u003cp\\u003eTwo patients with blepharoptosis gradually recovered after surgery. One patient (Case 11) developed transient oculomotor paralysis postoperatively. The postoperative hospital stay was approximately 5\\u0026ndash;12 days, and all cases were pathologically diagnosed as chordoma. Ten patients were followed for 40\\u0026ndash;59 months after the operation. The symptoms of headache, nasal obstruction, dizziness, and diplopia significantly improved compared with preoperative status. There were no occurrences of intracranial hemorrhage, postoperative CSF leakage, intracranial infection, or death. The four patients who underwent subtotal resection received proton radiation therapy, and no obvious tumor growth or recurrence was observed during follow-up.\\u003c/p\\u003e\"},{\"header\":\"Discussions\",\"content\":\"\\u003cp\\u003eChordomas occurring in the clivus of the skull base account for 0.1% \\u0026minus;\\u0026thinsp;0.7% of intracranial tumors\\u003csup\\u003e[\\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e]\\u003c/sup\\u003e. The clivus chordoma of the skull base is typically located on the ventral side of the dura mater. It can invade the parasellar or suprasellar region and extend into the skull, nasal cavity, and posterior pharyngeal wall. It can also invade the posterior cranial fossa, involve the cerebellopontine angle, or even compress the brainstem. Most patients have chronic symptoms that last for months to years. The clinical signs and symptoms have no obvious specific manifestations, and headache is the most common symptom. In our series, the manifestations included simple headache in 3 cases and dizziness in 2 cases. Clinical manifestations are closely related to the tumor size, position, and direction of invasion. CT and MRI are important imaging modalities for the preoperative diagnosis of skull base clivus chordoma\\u003csup\\u003e[\\u003cspan citationid=\\\"CR8\\\" class=\\\"CitationRef\\\"\\u003e8\\u003c/span\\u003e]\\u003c/sup\\u003e. However, imaging findings are similar to other space-occupying lesions of the skull base clivus, such as nasopharyngeal carcinoma, pituitary adenoma, and chondroma, and diagnosis often relies on postoperative histopathological examination\\u003csup\\u003e[\\u003cspan citationid=\\\"CR3\\\" class=\\\"CitationRef\\\"\\u003e3\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR6\\\" class=\\\"CitationRef\\\"\\u003e6\\u003c/span\\u003e]\\u003c/sup\\u003e.\\u003c/p\\u003e \\u003cp\\u003eSurgery is the primary treatment for chordoma of the skull base clivus. Complete resection along the tumor boundary is the optimal surgical approach. For patients in whom tumors cannot be completely resected, combined postoperative radiotherapy can also effectively improve the prognosis and delay the recurrence\\u003csup\\u003e[\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR7\\\" class=\\\"CitationRef\\\"\\u003e7\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR10\\\" class=\\\"CitationRef\\\"\\u003e10\\u003c/span\\u003e]\\u003c/sup\\u003e. Because of the deep position within the skull base, chordomas can cause severe clinical symptoms and show extensive invasion into the skull base, cavernous sinus, paranasal sinus, pterygopalatine fossa, infratemporal fossa, oropharynx, and involve important nerves and vessels, which makes total resection more difficult\\u003csup\\u003e[\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR12\\\" class=\\\"CitationRef\\\"\\u003e12\\u003c/span\\u003e]\\u003c/sup\\u003e. The application of EES has improved the GTR rate for skull base clivus chordoma\\u003csup\\u003e[\\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e]\\u003c/sup\\u003e. With the increasing number of publications reporting on EES for skull base chordomas, the GTR rate ranges from 33% to 86%\\u003csup\\u003e[\\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e]\\u003c/sup\\u003e.Bai J et.\\u003csup\\u003e[\\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e]\\u003c/sup\\u003e had reported 284 cases of clival chordomas about 74.6% of tumors were marginally resected,while Essayed WI et.\\u003csup\\u003e[\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e]\\u003c/sup\\u003e reported that the average extent of resection reached 97.7% with multimodal intraoperative image-driven surgery. In our series of 12 cases, GTR was achieved in 66.67% and STR in 33.33%. The use of neuronavigation may have contributed to this relatively favorable GTR rate by enabling real-time identification of critical structures during surgery. The tumor size, blood supply, texture, radiotherapy history, relationship with adjacent nerves and vessels, and invasion range of skull base clivus chordomas are often important factors that determine the difficulty of the operation and affect the total resection rate\\u003csup\\u003e[\\u003cspan citationid=\\\"CR2\\\" class=\\\"CitationRef\\\"\\u003e2\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR15\\\" class=\\\"CitationRef\\\"\\u003e15\\u003c/span\\u003e]\\u003c/sup\\u003e. In our series, 4 cases failed to achieve GTR because the tumors had invaded the cavernous sinus, pterygopalatine fossa, and infratemporal fossa. When the tumor invades the ICA or basilar artery, there is risk of vascular injury and massive bleeding\\u003csup\\u003e[\\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR17\\\" class=\\\"CitationRef\\\"\\u003e17\\u003c/span\\u003e]\\u003c/sup\\u003e. These four cases had tumors with tough texture, rich blood supply, and obvious adhesion to the paraclival ICA, which led to residual tumor (Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). After surgery, these patients received adjuvant radiotherapy. Dynamic follow-up re-examination showed that the tumors were well controlled.\\u003c/p\\u003e \\u003cp\\u003eFor complex skull base clivus chordoma, adequate preoperative evaluation is important to improve the efficacy and safety of surgery and to choose the appropriate surgical approach\\u003csup\\u003e[\\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e]\\u003c/sup\\u003e. Neuroendoscopy provides an ultra-high-definition surgical field of vision\\u003csup\\u003e[\\u003cspan citationid=\\\"CR5\\\" class=\\\"CitationRef\\\"\\u003e5\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e]\\u003c/sup\\u003e, enabling close observation with a wide exposure range and minimal blind spots. With the neuronavigation system, we can identify tumor resection extent and its relationship with surrounding structures, especially the ICA and vertebrobasilar artery\\u003csup\\u003e[\\u003cspan citationid=\\\"CR14\\\" class=\\\"CitationRef\\\"\\u003e14\\u003c/span\\u003e]\\u003c/sup\\u003e, even when the tumor surrounds the ICA(Fig.\\u0026nbsp;\\u003cspan refid=\\\"Fig2\\\" class=\\\"InternalRef\\\"\\u003e2\\u003c/span\\u003e). Moreover,we suggest routine cerebral angiography and balloon occlusion tests to identify compensation of the ICA on both sides and the anterior and posterior circulation. There was no obvious injury to important nerves and vessels in this group of cases. In the past, the neuronavigation system was prone to intraoperative displacement, with navigation data deviation and other problems. However, the navigation is now more accurate and reliable. These problems no longer bother us.\\u003c/p\\u003e \\u003cp\\u003eCSF leakage and cranial nerve injury have been the main complications reported in prior studies\\u003csup\\u003e[\\u003cspan citationid=\\\"CR4\\\" class=\\\"CitationRef\\\"\\u003e4\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR9\\\" class=\\\"CitationRef\\\"\\u003e9\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR11\\\" class=\\\"CitationRef\\\"\\u003e11\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR13\\\" class=\\\"CitationRef\\\"\\u003e13\\u003c/span\\u003e, \\u003cspan citationid=\\\"CR16\\\" class=\\\"CitationRef\\\"\\u003e16\\u003c/span\\u003e]\\u003c/sup\\u003e. In our series, two patients presented with CSF leakage before surgery and five patients developed CSF leakage during surgery. The skull base was repaired using multi-layer reconstruction techniques, including autologous fat tissue, artificial dura, autologous fascia lata-covered onlay, pedicled nasoseptal flap, biological protein glue, and urinary catheter balloon\\u003csup\\u003e[\\u003cspan citationid=\\\"CR18\\\" class=\\\"CitationRef\\\"\\u003e18\\u003c/span\\u003e]\\u003c/sup\\u003e. No postoperative cerebrospinal fluid leakage or new cranial nerve dysfunction was observed.\\u003c/p\\u003e \\u003cp\\u003eThis study has several limitations. First, the sample size is relatively small (n\\u0026thinsp;=\\u0026thinsp;12), which limits the generalizability of our findings. Second, as a retrospective single-center study without a control group, we cannot definitively compare outcomes with or without neuronavigation. Third, longer follow-up is needed to assess long-term recurrence rates. Despite these limitations, our results suggest that neuronavigation-assisted EES is a viable approach for skull base chordomas.\\u003c/p\\u003e\"},{\"header\":\"Conclusions\",\"content\":\"\\u003cp\\u003eIn this consecutive series of 12 patients with skull base chordomas, neuronavigation-assisted EES achieved a GTR rate of 66.67% with no major postoperative complications. Neuronavigation enables real-time identification of critical neurovascular structures, particularly the ICA and basilar artery, which enhances surgical safety and facilitates tumor resection. Combined with multilayer skull base reconstruction techniques, this approach effectively minimizes postoperative CSF leakage. Although limited by the small sample size, our results suggest that neuronavigation-assisted EES is a safe and effective approach for the treatment of skull base chordomas. Patients with subtotal resection may benefit from adjuvant radiotherapy to achieve tumor control.\\u003c/p\\u003e\"},{\"header\":\"Abbreviations\",\"content\":\"\\u003cp\\u003eEES,endoscopic endonasal surgery;ICA,Internal Carotid Artery; CSF,cerebrospinal fluid; GTR,Gross total resection;STR,subtotal resection;MRI,magnetic resonance imaging.\\u0026nbsp;\\u003c/p\\u003e\\n\"},{\"header\":\"Declarations\",\"content\":\"\\u003cp\\u003e\\u003cstrong\\u003eEthics Statement\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eClinical trial is not applicable. The need for further ethical approval was waived by the Ganzhou People\\u0026apos;s Hospital Research Committee owing to the retrospective nature of the study. This study was conducted in strict accordance with the principles of the Declaration of Helsinki.\\u0026nbsp;\\u003c/p\\u003e\\n\\u003cp\\u003ePatient consent was obtained from the patients，if the patients were children, the patient consent was obtained from the patients and guardian of patients in this study, including for the individual case details in Table 1.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eEthics approval and consent to participate\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThis study was approved by the Research Ethics Committee of Ganzhou People\\u0026apos;s Hospital (Approval No. 2022-012, dated March 10, 2022). Due to the retrospective nature of the study, the requirement for additional informed consent was waived by the committee. This study was conducted in strict accordance with the principles of the Declaration of Helsinki.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConsent to participate\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eWritten informed consent was obtained from all individual participants included in this study. For participants under the age of 18, consent was obtained from both the participant and their legal guardian.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eConsent for publication\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eNot applicable.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAvailability of data and material\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eAll data generated or analysed during this study are included in this published article.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eCompeting interests\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThe authors declare that they have no competing interests.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eFunding\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eThis study was funded by the Project of Science and Technology Plan of Ganzhou Science and Technology Bureau (GSKF [2019] No. 60), Jiangxi Provincial Health Commission Science and Technology Plan Project (SKJP202218028), and Jiangxi Province High-Level and High-Skilled Leading Talents Project Training Project (2021).\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAuthors\\u0026apos; contributions\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eYXY and JQH conceived and designed the study. HGL and LWT collected the data and performed data analyses. All authors contributed to the interpretation of the data and completion of the figures and tables. All authors contributed to the drafting of the manuscript and the final approval of the submitted version.\\u003c/p\\u003e\\n\\u003cp\\u003e\\u003cstrong\\u003eAcknowledgements\\u003c/strong\\u003e\\u003c/p\\u003e\\n\\u003cp\\u003eNot available.\\u003c/p\\u003e\"},{\"header\":\"References\",\"content\":\"\\u003col\\u003e\\u003cli\\u003e\\u003cspan\\u003eLanzino G, Dumont AS, Lopes MB, Laws ER Jr. Skull base chordomas: overview of disease, management options, and outcome. Neurosurg Focus. 2001;10(3):E12.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eIto E, Saito K, Okada T, Nagatani T, Nagasaka T. Long-term control of clival chordoma with initial aggressive surgical resection and gamma knife radiosurgery for recurrence. Acta Neurochir (Wien). 2010;152(1):57\\u0026ndash;67. discussion 67.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eFernandez-Miranda JC, Gardner PA, Snyderman CH, et al. Clival chordomas: A pathological, surgical, and radiotherapeutic review. Head Neck. 2014;36(6):892\\u0026ndash;906.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eCeylan S, Emengen A, Caklili M, et al. Operative nuances and surgical limits of the endoscopic approach to clival chordomas and chondrosarcomas: A single-center experience of 72 patients. Clin Neurol Neurosurg. 2021;208:106875.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eEssayed WI, Juvekar P, Bernstock JD et al. Multimodal Intraoperative Image-Driven Surgery for Skull Base Chordomas and Chondrosarcomas. Cancers (Basel). 2022. 14(4).\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eFrezza AM, Botta L, Trama A, Dei Tos AP, Stacchiotti S. Chordoma: update on disease, epidemiology, biology and medical therapies. Curr Opin Oncol. 2019;31(2):114\\u0026ndash;20.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eMcMaster ML, Goldstein AM, Bromley CM, Ishibe N, Parry DM. Chordoma: incidence and survival patterns in the United States, 1973\\u0026ndash;1995. Cancer Causes Control. 2001;12(1):1\\u0026ndash;11.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eTempany CM, Jayender J, Kapur T, et al. Multimodal imaging for improved diagnosis and treatment of cancers. Cancer. 2015;121(6):817\\u0026ndash;27.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eBai J, Li M, Shi J, et al. Mid-term follow-up surgical results in 284 cases of clival chordomas: the risk factors for outcome and tumor recurrence. Neurosurg Rev. 2022;45(2):1451\\u0026ndash;62.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eMetcalfe C, Muzaffar J, Kulendra K, et al. Chordomas and chondrosarcomas of the skull base: treatment and outcome analysis in a consecutive case series of 24 patients. World J Surg Oncol. 2021;19(1):68.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eWang B, Li Q, Sun Y, Tong X. Surgical Strategy for Skull Base Chordomas: Transnasal Midline Approach or Transcranial Lateral Approach. J Korean Neurosurg Soc. 2022.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003ePatra DP, Hess RA, Turcotte EL, et al. Surgical Outcomes with Midline versus Lateral Approaches for Cranial Base Chordomas: A Systematic Review and Meta-Analysis. World Neurosurg. 2020;140:378\\u0026ndash;e3882.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eBai J, Li M, Xiong Y, et al. Endoscopic Endonasal Surgical Strategy for Skull Base Chordomas Based on Tumor Growth Directions: Surgical Outcomes of 167 Patients During 3 Years. Front Oncol. 2021;11:724972.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eEssayed W, Mooney MA, Al-Mefty O. Transcavernous Resection of an Upper Clival Chondrosarcoma: Cavernous Sinus as a Route: 2-Dimensional Operative Video. Oper Neurosurg (Hagerstown). 2021. 20(6): E422\\u0026ndash;3.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eKim YH, Jeon C, Se YB, et al. Clinical outcomes of an endoscopic transclival and transpetrosal approach for primary skull base malignancies involving the clivus. J Neurosurg. 2018;128(5):1454\\u0026ndash;62.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eKoutourousiou M, Gardner PA, Tormenti MJ et al. Endoscopic endonasal approach for resection of cranial base chordomas: outcomes and learning curve. Neurosurgery. 2012. 71(3): 614\\u0026thinsp;\\u0026ndash;\\u0026thinsp;24; discussion 624-5.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eZhang Y, Tian Z, Li C, et al. A modified endovascular treatment protocol for iatrogenic internal carotid artery injuries following endoscopic endonasal surgery. J Neurosurg. 2019;132(2):343\\u0026ndash;50.\\u003c/span\\u003e\\u003c/li\\u003e \\u003cli\\u003e\\u003cspan\\u003eChampagne PO, Zenonos GA, Wang EW, Snyderman CH, Gardner PA. The rhinopharyngeal flap for reconstruction of lower clival and craniovertebral junction defects. J Neurosurg. 2021: 1\\u0026ndash;9.\\u003c/span\\u003e\\u003c/li\\u003e\\u003c/ol\\u003e\"}],\"fulltextSource\":\"\",\"fullText\":\"\",\"funders\":[],\"hasAdminPriorityOnWorkflow\":false,\"hasManuscriptDocX\":true,\"hasOptedInToPreprint\":true,\"hasPassedJournalQc\":\"\",\"hasAnyPriority\":false,\"hideJournal\":false,\"highlight\":\"\",\"institution\":\"\",\"isAcceptedByJournal\":false,\"isAuthorSuppliedPdf\":false,\"isDeskRejected\":\"\",\"isHiddenFromSearch\":false,\"isInQc\":false,\"isInWorkflow\":false,\"isPdf\":false,\"isPdfUpToDate\":true,\"isWithdrawnOrRetracted\":false,\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"bmc-neurology\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"nurl\",\"sideBox\":\"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)\",\"snPcode\":\"\",\"submissionUrl\":\"https://www.editorialmanager.com/nurl\",\"title\":\"BMC Neurology\",\"twitterHandle\":\"BMC_series\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"BMC Series\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":true},\"keywords\":\"Chordomas, Skull base, Neuronavigation, Endoscopy, Clivus\",\"lastPublishedDoi\":\"10.21203/rs.3.rs-8954762/v1\",\"lastPublishedDoiUrl\":\"https://doi.org/10.21203/rs.3.rs-8954762/v1\",\"license\":{\"name\":\"CC BY 4.0\",\"url\":\"https://creativecommons.org/licenses/by/4.0/\"},\"manuscriptAbstract\":\"\\u003cp\\u003eSkull base chordomas can be challenging to resect, and the degree of surgical resection is highly correlated with prognosis. With the rapid development of imaging, neuronavigation, and endoscopy, these technologies provide good technical support for improving the gross total resection rate of skull base clivus chordomas.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003eObjective\\u003c/b\\u003e: To analyze the clinical outcomes and extent of resection of neuronavigation-assisted endoscopic endonasal surgery in the treatment of skull base chordomas.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003eMethods\\u003c/b\\u003e: We retrospectively analyzed 12 patients (six males and six females, aged 9\\u0026ndash;70 years) with skull base chordomas in the Department of Neurosurgery of Ganzhou People's Hospital from May 2018 to April 2020.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003eResults\\u003c/b\\u003e: During the operation, 6 cases were exposed to the paraclival internal carotid artery, two patients experienced cerebrospinal fluid leakage before the operation, and four patients had tumors that broke through the dura, grew into the posterior cranial fossa, and adhered closely to the brain stem. Gross total resection was achieved in 66.67% (8 of twelve cases), and subtotal resection in 33.33% (4 of twelve cases). All patients were followed for 40\\u0026ndash;59 months after the operation. The patients' symptoms improved postoperatively.\\u003c/p\\u003e \\u003cp\\u003e \\u003cb\\u003eConclusions\\u003c/b\\u003e: Neuronavigation-assisted EES is an effective approach for treating skull base chordomas.\\u003c/p\\u003e\",\"manuscriptTitle\":\"Neuronavigation assisted Endoscopic Endonasal Surgery for Skull Base Chordomas: treatment and outcome analysis in a consecutive case series of 12 patients\",\"msid\":\"\",\"msnumber\":\"\",\"nonDraftVersions\":[{\"code\":1,\"date\":\"2026-03-08 16:36:22\",\"doi\":\"10.21203/rs.3.rs-8954762/v1\",\"editorialEvents\":[{\"type\":\"communityComments\",\"content\":0},{\"type\":\"decision\",\"content\":\"Revision requested\",\"date\":\"2026-03-12T02:40:42+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2026-03-11T11:06:08+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"233458314723909208970126718077835006136\",\"date\":\"2026-03-05T22:38:08+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"editorInvitedReview\",\"content\":\"\",\"date\":\"2026-03-04T06:41:48+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"20409795030448718846019122244100208587\",\"date\":\"2026-03-01T23:25:40+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewerAgreed\",\"content\":\"182920804613776419449878443501896520498\",\"date\":\"2026-02-28T19:32:53+00:00\",\"index\":\"hide\",\"fulltext\":\"\"},{\"type\":\"reviewersInvited\",\"content\":\"\",\"date\":\"2026-02-27T15:09:39+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorInvited\",\"content\":\"\",\"date\":\"2026-02-27T03:50:48+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"editorAssigned\",\"content\":\"\",\"date\":\"2026-02-27T00:38:55+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"checksComplete\",\"content\":\"\",\"date\":\"2026-02-27T00:37:28+00:00\",\"index\":\"\",\"fulltext\":\"\"},{\"type\":\"submitted\",\"content\":\"BMC Neurology\",\"date\":\"2026-02-24T08:25:52+00:00\",\"index\":\"\",\"fulltext\":\"\"}],\"status\":\"published\",\"journal\":{\"display\":true,\"email\":\"info@researchsquare.com\",\"identity\":\"bmc-neurology\",\"isNatureJournal\":false,\"hasQc\":true,\"allowDirectSubmit\":false,\"externalIdentity\":\"nurl\",\"sideBox\":\"Learn more about [BMC Neurology](http://bmcneurol.biomedcentral.com/)\",\"snPcode\":\"\",\"submissionUrl\":\"https://www.editorialmanager.com/nurl\",\"title\":\"BMC Neurology\",\"twitterHandle\":\"BMC_series\",\"acdcEnabled\":true,\"dfaEnabled\":false,\"editorialSystem\":\"em\",\"reportingPortfolio\":\"BMC Series\",\"inReviewEnabled\":true,\"inReviewRevisionsEnabled\":true}}],\"origin\":\"\",\"ownerIdentity\":\"1d8e649b-f5e8-4581-adb5-791df5d852ce\",\"owner\":[],\"postedDate\":\"March 8th, 2026\",\"published\":true,\"recentEditorialEvents\":[],\"rejectedJournal\":[],\"revision\":\"\",\"amendment\":\"\",\"status\":\"in-revision\",\"subjectAreas\":[],\"tags\":[],\"updatedAt\":\"2026-03-12T02:55:01+00:00\",\"versionOfRecord\":[],\"versionCreatedAt\":\"2026-03-08 16:36:22\",\"video\":\"\",\"vorDoi\":\"\",\"vorDoiUrl\":\"\",\"workflowStages\":[]},\"version\":\"v1\",\"identity\":\"rs-8954762\",\"journalConfig\":\"researchsquare\"},\"__N_SSP\":true},\"page\":\"/article/[identity]/[[...version]]\",\"query\":{\"redirect\":\"/article/rs-8954762\",\"identity\":\"rs-8954762\",\"version\":[\"v1\"]},\"buildId\":\"XKTyCvWXoU3ODBz1xrDgd\",\"isFallback\":false,\"isExperimentalCompile\":false,\"dynamicIds\":[84888],\"gssp\":true,\"scriptLoader\":[]}","source_license":"CC-BY-4.0","license_restricted":false}