[Overview and prospects of endoscopic skull base surgery].

Endoscopic skull base surgery presents significant technical challenges and high surgical risks, requiring collaboration among multiple disciplines such as otolaryngology, neurosurgery, ophthalmology, and oral maxillofacial surgery. In recent years, there has been rapid development in endoscopic skull base surgery, characterized by flourishing anatomical research and an expanding range of surgical indications. The future brings both opportunities and challenges, and endoscopic skull base surgery must grasp new directions in medical development, actively providing patients with safer and more effective treatment options.

[Clinical analysis of resection and dura skull base reconstruction of cranionasal communication tumor in 31 cases].

Objective:To explore the methods of resection, dura and skull base repair and reconstruction of cranionasal communication tumor. Methods:Data of 31 patients with cranionasal communication tumor who underwent dura and skull base reconstruction after tumor resection from 2018 to 2022 were collected. Follow-up lasted for 3 to 41 months. Results:A total of 31 patients were enrolled, including 20 males and 11 females. The ages ranged from 19 to 74 years, with a median age of 57 years old. There were 17 benign lesions（one case of hemangioma, one case of Rathke cyst, one case of squamous papilloma, one case of craniopharyngioma, two cases of meningocele, two cases of varus papilloma, two cases of meningioma of grade Ⅰ, three cases of schwannoma, four cases of pituitary tumor） and 14 malignant lesions（one case of osteosarcoma, one case of poorly differentiated carcinoma, two cases of varus papilloma malignancy, two cases of olfactory neuroblastoma, two cases of adenocarcinoma, two cases of adenoid cystic carcinoma, four cases of squamous cell carcinoma） . Sixteen cases underwent nasal endoscopy combined with craniofacial incision and 15 cases underwent nasal endoscopy surgery alone. Complete resection of the mass and dura and skull base reconstruction were performed in all 31 patients, and free graft repair was performed in 8 cases（fascia lata in 5 cases and nasal mucosa in 3 cases）. Twenty-three cases were repaired with pedicled flaps（septal mucosal flap alone in 11 cases, septal mucosal flap combined with free graft in 6 cases, and cap aponeurosis combined with free graft in 6 cases）. Eight out of 31 patients underwent skull base bone repair. Postoperative cerebral hemorrhage occurred in 1 case, cerebrospinal fluid leakage in 1 case, intracranial infection in 2 cases. All patients were successfully treated without severe sequelae. Cerebrospinal fluid leakage and intracranial infection occurred in one patient after radiotherapy, who recovered after conservative treatment. All 17 patients with benign lesions survived. Thirteen out of 14 patients with malignant lesions received radiotherapy after surgery, nine survived without recurrence, five cases recurred, of which 2 survived with tumor, one underwent reoperation and 2 died. Conclusion:Cranionasal communication tumors are high-risk diseases of anterior and middle skull base, and various surgical repair methods could be selected after complete resection of the tumor. Successful reconstruction and multidisciplinary cooperation are crucial for treatment outcome.

[Transoral approach in surgery for chordomas extending into craniovertebral junction: a systematic review of the literature]. / Transoral'nyi dostup v khirurgii khordom, rasprostranyayushchikhsya v oblast' kraniovertebral'nogo perekhoda: sistematicheskii obzor literatury.

To date, treatment of chordomas involves maximal tumor resection followed by proton therapy. Various approaches are used depending on location of tumor (transcranial and through natural anatomical openings (nose, mouth), as well as their combinations). Although transoral approach has been introduced into neurosurgical practice for a long time, it is routinely used in patients with chordoma only in certain hospitals in the world. OBJECTIVE: To analyze postoperative outcomes in patients with chordomas of skull base and craniovertebral joint after transoral surgery. MATERIAL AND METHODS: We analyzed literature data devoted to patients with chordomas of skull base and craniovertebral joint after transoral surgery or another approach combined with transoral access. Among 111 primary articles, we selected 38 manuscripts including description of 109 patients with skull base chordoma who underwent transoral surgery or combination of approaches including transoral one. RESULTS: Gross total resection was achieved in 45.9% (n=50) of cases including 1 patient after en bloc resection. Subtotal resection was carried out in 28.4% of cases, partial - in 24.8%, biopsy - in 0.9% of cases. The complication rate in this group was 30%. The most common events were swelling of the tongue (10%) and diastasis of posterior pharyngeal wall sutures (8.2%) that required redo surgery. CSF leakage and meningitis were rare (1.8% and 3.6%, respectively). CONCLUSION: Transoral access allows for gross total resection of midline tumors with low incidence of severe complications. Combination of transoral and transcranial approaches is advisable to increase extent of resection.

Microsurgical resection of a samii type D jugular foramen schwannoma via the carotid triangle without removal of bony structure: how I do it.

BACKGROUND: Samii Type-D jugular foramen schwannomas (JFSs) are the most challenging for neurosurgeons because of anatomical complexity. Various neurosurgical approaches have been described to gain access to JF. METHODS: We present a female with incidental diagnosis of the Type-D JFS. Complete radical resection was achieved via the carotid triangle approach without any bony structure removal. And the patient was discharged asymptomatic and without new-developed neurological deficits. CONCLUSIONS: The carotid triangle is a secure and appropriate approach for some cases of selected Type-D JFSs. However, the specific indications of this approach should be further explored and investigated.

Safety and efficacy of hydroset cranioplasty as an adjunct to gasket-seal and nasoseptal flap closure of the skull base. A case-controlled study.

BACKGROUND: Cerebrospinal fluid leak after endoscopic skull base surgery remains a significant complication. Several investigators have suggested Hydroset cranioplasty to reduce leak rates. We investigated our early experience with Hydroset and compared the rate of nasal complications and CSF leak rates with case-controlled historic controls. METHODS: We queried a prospective database of patients undergoing first time endoscopic, endonasal resection of suprasellar meningiomas and craniopharyngiomas from 2015 to 2023. We compared cases closed with a gasket seal, Hydroset, and a nasoseptal flap with those closed with only a gasket seal and nasoseptal flap. Demographics, technical considerations and postoperative outcomes (SNOT-22) were compared. RESULTS: Seventy patients met inclusion criteria, twenty patients in the Hydroset group (meningioma n = 12; craniopharyngioma n = 8) and 50 control patients (meningioma n = 25; craniopharyngioma n = 25). CSF diversion was used in fewer Hydroset patients (75%, 15/20) compared with control group (94%, 47/50; p = 0.02). CSF leak was less frequent in the Hydroset than the control group (5% versus 12%, p = 0.38). One Hydroset patient required delayed nasal debridement. SNOT-22 responses demonstrated no significant difference in sinonasal complaints between groups (Hydroset average SNOT-22 score 22.45, control average SNOT-22 score 25.90; p = 0.58). CONCLUSIONS: We demonstrate that hydroxyapatite reconstruction leads to improved CSF leak control above that provided by the gasket-seal and nasoseptal flap, without significant associated morbidity as long as the cement is fully covered with vascularized tissue.

Jugular Foramen Paragangliomas.

Paragangliomas are the most common tumors at jugular foramen and pose a great surgical challenge. Careful clinical history and physical examination must be performed to adequately evaluate neurological deficits and its chronologic evolution, also to delineate an overview of the patient performance status. Complete imaging evaluation including MRI and CT scans should be performed, and angiography is a must to depict tumor blood supply and sigmoid sinus/internal jugular vein patency. Screening for multifocal paragangliomas is advisable, with a whole-body imaging. Laboratory investigation of endocrine function of the tumor is necessary, and adrenergic tumors may be associated with synchronous lesions. Preoperative prepare with alpha-blockage is advisable in norepinephrine/epinephrine-secreting tumors; however, it is not advisable in exclusively dopamine-secreting neoplasms. Best surgical candidates are young otherwise healthy patients with smaller lesions; however, treatment should be individualized each case. Variations of infratemporal fossa approach are employed depending on extensions of the mass. Regarding facial nerve management, we avoid to expose or reroute it if there is preoperative function preservation and prefer to work around facial canal in way of a fallopian bridge technique. If there is preoperative facial nerve compromise, the mastoid segment of the nerve is exposed, and it may be grafted if invaded or just decompressed. A key point is to preserve the anteromedial wall of internal jugular vein if there is preoperative preservation of lower cranial nerves. Careful multilayer closure is essential to avoid at most cerebrospinal fluid leakage. Residual tumors may be reoperated if growing and presenting mass effect or be candidate for adjuvant stereotactic radiosurgery.

Long-term outcome of primary clival chordomas: a single-center retrospective study with an emphasis on the timing of recurrences based on the primary treatment.

OBJECTIVE: This study aimed to provide data on extended outcomes in primary clival chordomas, focusing on progression-free survival (PFS) and overall survival (OS). METHODS: A retrospective single-center analysis was conducted on patients with clival chordoma treated between 1987 and 2022 using surgery, stereotactic radiosurgery, or proton radiation therapy (PRT). RESULTS: The study included 100 patients (median age 44 years, 51% male). Surgery was performed using the endoscopic endonasal approach in 71 patients (71%). Gross-total resection (GTR) or near-total resection (NTR) was attained in 39 patients (39%). Postoperatively, new cranial nerve deficits occurred in 7%, CSF leak in 4%, and meningitis in none of the patients. Radiation therapy was performed in 79 patients (79%), with PRT in 50 patients (50%) as the primary treatment. During the median follow-up period of 73 (interquartile range [IQR] 38-132) months, 41 recurrences (41%) and 31 deaths (31%) were confirmed. Patients with GTR/NTR had a median PFS of 41 (IQR 24-70) months. Patients with subtotal resection or biopsy had a median PFS of 38 (IQR 16-97) months. The median PFS of patients who received radiation therapy was 43 (IQR 26-86) months, while that of patients who did not receive radiation therapy was 18 (IQR 5-62) months. The Kaplan-Meier method showed that patients with GTR/NTR (p = 0.007) and those who received radiation therapy (p < 0.001) had longer PFS than their counterparts. The PFS rates following primary treatment at 5, 10, 15, and 20 years were 51%, 25%, 17%, and 7%, respectively. The OS rates at the same intervals were 84%, 60%, 42%, and 34%, respectively. Multivariate Cox regression analysis showed that age < 44 years (p = 0.02), greater extent of resection (EOR; p = 0.03), and radiation therapy (p < 0.001) were associated with lower recurrence rates. Another multivariate analysis showed that age < 44 years (p = 0.01), greater EOR (p = 0.04), and freedom from recurrence (p = 0.02) were associated with lower mortality rates. Regarding pathology data, brachyury was positive in 98%, pan-cytokeratin in 93%, epithelial membrane antigen in 85%, and S100 in 74%. No immunohistochemical markers were associated with recurrence. CONCLUSIONS: In this study, younger age, maximal safe resection, and radiation therapy were important factors for longer PFS in patients with primary clival chordomas. Preventing recurrences played a crucial role in achieving longer OS.

A comparison of endoscopic endonasal versus open approaches for skull base chordoma: a comprehensive National Cancer Database analysis.

OBJECTIVE: The authors of this study aimed to investigate independent prognostic factors of survival with a particular focus on comparing the safety and efficacy of endoscopic endonasal versus open approaches in the surgical management of skull base chordoma. METHODS: A retrospective National Cancer Database review of skull base chordoma patients was performed to capture resection cases from 2010 to 2020, evaluating overall survival (OS), early postoperative mortality, readmission rates, and hospital length of stay (LOS) between surgical approaches and the independent prognostication of death utilizing Cox multivariate regression analysis. RESULTS: Among the 736 patients included in the cohort, 456 patients (62.0%) and 280 patients (38.0%) underwent endoscopic endonasal and open resection, respectively. These values represent a rate of change over the study period of +4.1 versus -0.14 cases per year, respectively. Gross-total resection was achieved in 32.5% of cases. A positive margin status was found in 51.8% of cases. There was no association between extent of resection and surgical approach (p = 0.257). There was no difference in OS (p = 0.562), 30- and 90-day mortality (p = 0.209 and 0.126, respectively), and 30-day readmission (p = 0.438) between the two surgical groups. The mean LOS was reduced by 2.1 days in the endoscopic cohort (p = 0.013) compared with the open approach cohort. Finally, multivariate analysis revealed a tumor size ≥ 4 cm (HR 4.03, p = 0.005) and public insurance (HR 2.76, p = 0.004) as negative predictors of survival and treatment at an academic center (HR 0.36, p = 0.043) as a positive prognosticator of survival. CONCLUSIONS: The endoscopic endonasal approach has been increasingly utilized over time and touts noninferiority with respect to safety and efficacy with a marked improvement in LOS, which carries substantial implications for both healthcare costs and enhanced patient recovery. Future prospective studies are necessary to further delineate trends and surgical outcomes for skull base chordoma.

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

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

Supramarginal resection of skull base chordomas: proof of concept and preliminary outcomes.

OBJECTIVE: The mainstay of treatment for skull base chordoma (SBC) is maximal safe resection followed by radiotherapy. However, even after gross-total resection (GTR), the recurrence rate is high due to microscopic disease in the resection margins. Therefore, supramarginal resection (SMR) could be beneficial, as has been shown for sacral chordoma. The paradigm of postoperative radiation therapy for every patient has also begun to change, as molecular profiling has shown variability in the risk of recurrence. The aim of this study was to present the concept of SMR applied to SBC, along with an individualized decision for postoperative radiation therapy. METHODS: This is a retrospective analysis of all SBCs operated on by the senior author between 2018 and 2023. SMR was defined as negative histological margins of bone and/or dura mater, along with evidence of bone resection beyond the tumor margins in the craniocaudal and lateral planes on postoperative imaging. Tumors were classified into 3 molecular recurrence risk groups (group A, low risk; group B, intermediate risk; and group C, high risk). Postoperative radiation therapy was indicated in group C tumors, in group B chordomas without SMR, or in cases of patient preference. RESULTS: Twenty-two cases of SBC fulfilled the inclusion criteria. SMR was achieved in 12 (55%) cases, with a mean (range) amount of bone resection beyond the tumor margins of 10 (2-20) mm (+40%) in the craniocaudal axis and 6 (1-15) mm (+31%) in the lateral plane. GTR and near-total resection were each achieved in 5 (23%) cases. Three (19%) tumors were classified as group A, 12 (75%) as group B, and 1 (6%) as group C. Although nonsignificant due to the small sample size, the trends showed that patients in the SMR group had smaller tumor volumes (13.9 vs 19.6 cm3, p = 0.35), fewer previous treatments (33% vs 60% of patients, p = 0.39), and less use of postoperative radiotherapy (25% vs 60%, p = 0.19) compared to patients in the non-SMR group. There were no significant differences in postoperative CSF leak (0% vs 10%, p = 0.45), persistent cranial nerve palsy (8% vs 20%, p = 0.57), and tumor recurrence (8% vs 10%, p = 0.99; mean follow-up 15 months) rates between the SMR and non-SMR groups. CONCLUSIONS: In select cases, SMR of SBC appears to be feasible and safe. Larger cohorts and longer follow-up evaluations are necessary to explore the benefit of SMR and individualized postoperative radiation therapy on progression-free survival.

The burden of skull base chordomas: insights from a meta-analysis of observational studies.

OBJECTIVE: The aim of this study was to provide a quantitative synthesis of the survival outcomes for patients with skull base chordomas, focusing on the role of 1) the extent of resection (gross-total [GTR] vs non-GTR), 2) the type of surgery (primary vs revision), 3) tumor histology, and 4) the different use of adjuvant therapies (proton beam radiotherapy [PBRT], photon radiotherapy [RT], or none). METHODS: A systematic review with a meta-analysis was conducted following the 2020 PRISMA guidelines. Observational studies describing adult and pediatric patient cohorts harboring skull base chordomas were included. The primary outcome measures were represented by the 5-year overall survival (OS) and progression-free survival (PFS) rates. The main intervention effects were represented by the extent of resection (GTR vs non-GTR), type of surgical excision (primary vs revision surgeries), tumor histology, and the different use of adjuvant therapies (PBRT, RT, or none). The pooled estimates were calculated using random forest models. The risk of bias was evaluated using the Joanna Briggs Institute checklist for case series. RESULTS: Six hundred forty-four studies were identified through a database and register search. After study selection, 51 studies and 3871 patients were included in the meta-analysis. The overall 5-year OS rate was 73%, which increased to 84% among patients undergoing GTR. The overall 5-year PFS rate was 52%, increasing to 74% for patients receiving GTR. The 5-year OS and PFS rates for patients undergoing PBRT were 86% and 71%, compared with 71% and 54% for patients receiving RT, and 55% and 25% when no adjuvant treatments were used. Patients undergoing their first surgery had 2.13-fold greater chances of being disease-free and 1.4-fold greater chances of being alive at 5 years follow-up compared with patients who received a revision surgery. Patients harboring chondroid chordomas had 1.13- and 1.9-fold greater chances of being alive at 5 years compared with patients with conventional and de-differentiated chordomas, respectively. The overall risk of bias was low in the included studies. CONCLUSIONS: The results of this comprehensive meta-analysis highlight the tremendous impact of GTR and adjuvant PBRT on improving OS and PFS of patients harboring skull base chordomas, with better survival rates demonstrated for patients with chondroid tumors. Even in experienced hands, the rate of surgical morbidity remains high. Proper management in high-volume centers is mandatory to reach the expected resection goal at the first surgical attempt and to reduce surgical morbidity. The introduction of the endoscopic endonasal approach was related to improved surgical and functional outcomes.

Stereotactic radiosurgery in the management of skull base chordomas: a comprehensive systematic review and meta-analysis.

OBJECTIVE: Chordoma is a primary bone tumor with limited literature on its management because of its rarity. Resection, while considered the first-line treatment, does not always provide adequate tumor control. In this systematic review, the authors aimed to provide comprehensive insights by managing these tumors with stereotactic radiosurgery (SRS). METHODS: A systematic review was conducted according to PRISMA guidelines using the PubMed, Scopus, Web of Science, Embase, and Cochrane Library databases. Search terms included chordoma and radiosurgery and their equivalent terms. Data on baseline characteristics, SRS details, and outcomes were extracted. The Joanna Briggs Institute checklist was used to assess risk of bias. A meta-analysis was performed on relevant variables. RESULTS: A total of 33 eligible studies encompassing 714 patients with skull base chordomas were included. Most studies had a low risk of bias. Patients, predominantly male (57.37%) with a mean age of 46.54 years, exhibited a conventional chordoma subtype (74.77%) and primary lesions (77.91%), mainly in the clivus (98.04%). The mean lesion volume was 13.49 cm3, and 96.68% of patients had undergone prior surgical attempts. Gamma Knife radiosurgery (88.76%) was the predominant SRS method. Radiologically, 27.19% of patients experienced tumor regression, while 55.02% showed no signs of disease progression at the latest follow-up. Progression occurred after a mean of 48.02 months. Symptom improvement was noted in 27.98% of patients. Radiosurgery was associated with a relatively low overall adverse event rate (11.94%), mainly cranial nerve deficits (8.72%). Meta-regression revealed that age and primary lesion type influenced symptom improvement, while factors like extent of resection, radiotherapy, and SRS type affected adverse event rates. CONCLUSIONS: This systematic review provides evidence on the safety and effectiveness of radiosurgery in the management of skull base chordomas. Local tumor control was achieved in the majority of patients treated with SRS. Various baseline characteristics and SRS features have been analyzed to identify modifying factors for each outcome to provide a framework for informed decision-making when managing these patients.

Optimizing radiotherapy strategies for skull base chordoma: a comprehensive meta-analysis and systematic review of treatment modalities and outcomes.

OBJECTIVE: In the treatment of skull base chordoma (SBC) surgery is considered the mainstay approach, and gross-total resection has an established relationship with progression-free survival (PFS) and overall survival (OS). However, the tumor's location often interferes with attempts at complete resection. In this case, surgery for maximal resection followed by high-dose radiotherapy has been demonstrated to be the standard treatment. In this context, various modalities are available, yet no consensus exists on the most effective. This systematic review and meta-analysis aimed to evaluate the efficacy and safety of different radiotherapy modalities for SBC. METHODS: Following PRISMA guidelines, the authors systematically searched for the treatment of SBC with radiation modalities in the PubMed, Cochrane, Web of Science, and EMBASE databases. Outcomes assessed for each modality were as follows: OS, PFS, local control (LC), and complications. The random-effects model was adopted. A single-proportion analysis with 95% CI was used to measure the effects in single-arm analysis. For the comparative analysis, the OR with 95% CI was used to compare outcome treatment effects. Heterogeneity was assessed using I2 statistics, and statistical significance was defined as p < 0.05. RESULTS: A total of 32 studies comprising 3663 patients, with 2322 patients who were treated with radiotherapeutic modalities, were included. Regarding 5-year OS findings in each modality study, the findings were as follows: in photon fractionated radiotherapy, an estimated rate of 77% (69%-84%, 568 patients); in conventional fractionated radiotherapy, 76% (65%-87%, 517 cases); in proton-based + carbon ion-based radiotherapy, 85% (82%-88%, 622 cases); and in a comparative analysis of proton-based and carbon ion-based therapy, there was an OR of 1.2 (95% CI 0.59-2.43, 306 cases). Regarding the 5-year PFS estimate, the rates were as follows: 35% (26%-45%, 95 cases) for photon fractionated therapy; 35% (25%-45%, 85 cases) for stereotactic radiotherapy; 77% (50%-100%, 180 cases) for proton-based and carbon ion-based radiotherapy; and 74% (45%-100%, 102 cases) for proton-based radiotherapy. Regarding LC in periods of 3 and 5 years after proton- and carbon ion-based therapy, the overall estimated rates were 84% (78%-90%, 326 cases) and 75% (65%-85%, 448 cases), respectively. For proton-based radiotherapy and carbon ion-based therapy, the 5-year LC rates were 76% (67%-86%, 259 cases) and 75% (59%-91%, 189 cases), respectively. CONCLUSIONS: The analysis highlights the finding that particle-based modalities like proton beam radiotherapy and carbon ion radiotherapy are the most effective radiation therapies available for the treatment of SBC. Furthermore, it reinforces the idea that surgery followed by radiotherapy constitutes the standard treatment.

Anatomical determinants of occipitocervical fusion in skull base chordoma resection: a systematic review of the literature with illustrative cases.

OBJECTIVE: Skull base chordomas are rare, locally osseo-destructive lesions that present unique surgical challenges due to their involvement of critical neurovascular and bony structures at the craniovertebral junction (CVJ). Radical cytoreductive surgery improves survival but also carries significant morbidity, including the potential for occipitocervical (OC) destabilization requiring instrumented fusion. The published experience on OC fusion after CVJ chordoma resection is limited, and the anatomical predictors of OC instability in this context remain unclear. METHODS: PubMed and Embase were systematically searched according to the PRISMA guidelines for studies describing skull base chordoma resection and OC fusion. The search strategy was predefined in the authors' PROSPERO protocol (CRD42024496158). RESULTS: The systematic review identified 11 surgical case series describing 209 skull base chordoma patients and 116 (55.5%) who underwent OC instrumented fusion. Most patients underwent lateral approaches (n = 82) for chordoma resection, followed by midline (n = 48) and combined (n = 6) approaches. OC fusion was most often performed as a second-stage procedure (n = 53), followed by single-stage resection and fusion (n = 38). The degree of occipital condyle resection associated with OC fusion was described in 9 studies: total unilateral condylectomy reliably predicted OC fusion regardless of surgical approach. After lateral transcranial approaches, 4 studies cited at least 50%-70% unilateral condylectomy as necessitating OC fusion. After midline approaches-most frequently the endoscopic endonasal approach (EEA)-at least 75% unilateral condylectomy (or 50% bilateral condylectomy) led to OC fusion. Additionally, resection of the medial atlantoaxial joint elements (the C1 anterior arch and tip of the dens), usually via EEA, reliably necessitated OC fusion. Two illustrative cases are subsequently presented, further exemplifying how the extent of CVJ bony elements removed via EEA to achieve complete chordoma resection predicts the need for OC fusion. CONCLUSIONS: Unilateral total condylectomy, 50% bilateral condylectomy, and resection of the medial atlantoaxial joint elements were the most frequently described independent predictors of OC fusion in skull base chordoma resection. Additionally, consistent with the occipital condyle harboring a significantly thicker joint capsule at its posterolateral aspect, an anterior midline approach seems to tolerate a greater degree of condylar resection (75%) than a lateral transcranial approach (50%-70%) prior to generating OC instability.

Interdisciplinary Management of Skull Base Tumors. / Interdisziplinäre Behandlung von Schädelbasistumoren.

OBJECTIVE: Endoscopic endonasal skull base surgery has gained acceptance worldwide. Comparative analysis has demonstrated that endoscopic skull base surgery may have advantages for many pathologies of the anterior skull base, e. g., sinonasal malignant tumors; pathologies of the central skull base, e. g., pituitary adenomas, craniopharyngiomas; well-selected cases of planum sphenoidale and tuberculum sellae meningiomas; or for clival lesions, e. g., chordomas, chondrosarcomas, or selected meningiomas. Over the past three decades, interdisciplinary surgical teams, consisting of otolaryngologists and neurosurgeons, have provided detailed anatomical knowledge, suggested new approaches or modifications of established surgical techniques, and offered continued surgical education. METHOD: A review of pertinent literature was conducted with an emphasis on interdisciplinary endoscopic surgery of skull base lesions. RESULTS: Based on the authors̓ surgical experience in two different interdisciplinary endoscopic skull base centers, the authors classify approaches for endoscopic endonasal skull base surgery, describe indications, and key anatomic landmarks for common pathologies, and highlight surgical techniques to avoid complications. CONCLUSION: Interdisciplinary endonasal endoscopic surgery combines surgical expertise, improves resection rates for many pathologies, and minimizes morbidity by reducing the incidence of surgical complications.

Comparative analysis of transnasal endoscopic reconstruction techniques for managing cerebrospinal fluid rhinorrhea in skull base defects.

The nasal skull base is located into the deep position of nasal cavity and closely related to important nerves and vessels. The complete removal of tumors in this area poses a complex surgical challenge.In order to investigate the clinical efficacy of utilizing free middle turbinate mucosa (FMT), fascia lata, and pedicled nasal septum flap (known as the Hadad-Bassagasteguy flap, HBF) for the treatment of cerebrospinal fluid (CSF) rhinorrhea, a retrospective analysis was conducted on clinical data from 65 patients who underwent skull base reconstruction following endoscopic resection of nasal-skull base tumors. The selection of the repair material was based on the size and location of the defect. For defects less than 1.5 cm (n = 24), FMT was chosen, while for defects greater than or equal to 1.5 cm (n = 16), HBF was preferred. In cases where HBF was not available or not suitable (specifically, when the defect was located on the posterior wall of the frontal sinus), fascia lata was selected (n = 25). The repair outcomes of all 65 patients were summarized, and subsequently, a comparison was made between the use of fascia lata and HBF. The overall success rate for one-time repairs was 93.8 %. Specifically, the success rates for repairs using FMT, fascia lata, and HBF were 91.7 %, 96.0 %, and 93.8 %, respectively. Throughout the follow-up period, there were 2 cases of postoperative CSF leakage out of 24 patients who underwent FMT reconstruction, 1 case out of 25 patients who underwent fascia lata reconstruction, and 1 case out of 16 patients who underwent HBF reconstruction. The occurrence of postoperative complications, such as intracranial infection, lung infection, and epistaxis, was observed in both the fascia lata group and the HBF group. However, there were no statistically significant differences between the two groups. The transnasal endoscopic reconstruction of skull base defect using HBF, fascia lata, and FMT demonstrated satisfactory repair effects in managing CSF rhinorrhea. Generally, FMT has been found to be a dependable repair material for small defects measuring less than 1.5 cm, while in the case of larger defects equal to or exceeding 1.5 cm, both HBF and fascia lata can be utilized with comparable repair outcomes. The selection of fascia lata becomes a viable option when HBF is unavailable or not suitable.

Phantom study of a fully automatic radioactive seed placement robot for the treatment of skull base tumours.

BACKGROUND: Interstitial brachytherapy is a form of intensive local irradiation that facilitates the effective protection of surrounding structures and the preservation of organ functions, resulting in a favourable therapeutic response. As surgical robots can perform needle placement with a high level of accuracy, our team developed a fully automatic radioactive seed placement robot, and this study aimed to evaluate the accuracy and feasibility of fully automatic radioactive seed placement for the treatment of tumours in the skull base. METHODS: A fully automatic radioactive seed placement robot was established, and 4 phantoms of skull base tumours were built for experimental validation. All the phantoms were subjected to computed tomography (CT) scans. Then, the CT data were imported into the Remebot software to design the preoperative seed placement plan. After the phantoms were fixed in place, navigation registration of the Remebot was carried out, and the automatic seed placement device was controlled to complete the needle insertion and particle placement operations. After all of the seeds were implanted in the 4 phantoms, postoperative image scanning was performed, and the results were verified via image fusion. RESULTS: A total of 120 seeds were implanted in 4 phantoms. The average error of seed placement was (2.51 ± 1.44) mm. CONCLUSION: This study presents an innovative, fully automated radioactive particle implantation system utilizing the Remebot device, which can successfully complete automated localization, needle insertion, and radioactive particle implantation procedures for skull base tumours. The phantom experiments showed the robotic system to be reliable, stable, efficient and safe. However, further research on the needle-soft tissue interaction and deformation mechanism of needle puncture is still needed.

Free temporalis muscle fascia graft in dural reconstruction following surgical resection of intermediate and malignant skull base tumors: A 10-year experience from a single center.

BACKGROUND: Data from patients with post-ablative dural defects reconstructed using a free temporalis muscle fascia graft (FTFG) after resection of anterior or central skull base tumors were retrospectively analyzed. METHODS: The primary predictor and outcome variables were the reconstructive methods for dural repair and postoperative cerebrospinal fluid (CSF) leakage rate, respectively. RESULTS: Eighty patients were included, and 94 postoperative dural reconstructions were performed using FTFG. The postoperative CSF leakage rate was 3.19%. The postoperative CSF leakage rates did not significantly differ between open and endonasal endoscopic surgeries (1.92% vs. 4.88%; p > 0.05). In cases completed using the endonasal endoscopic approach, the postoperative CSF leakage rate was significantly associated with the intraoperative CSF leak flow (p < 0.05). CONCLUSIONS: Post-ablative dural defect reconstruction using FTFG resulted in low postoperative CSF leakage and complication rates comparable to those of free fascia lata graft from available literature.

Gamma knife radiosurgery for clival metastasis: case series and systematic review.

PURPOSE: Clival metastatic cancer is rare and has limited literature to guide management. We describe management of clival metastasis with Gamma Knife radiosurgery (GKRS). We augment our findings with a systematic review of all forms of radiation therapy for clival metastasis. METHODS: Records of 14 patients with clival metastasis who underwent GKRS at the University of Pittsburgh Medical Center from 2002 to 2023 were reviewed. Treatment parameters and clinical outcomes were assessed. A systematic review was conducted using evidence-based guidelines. RESULTS: The average age was 61 years with male predominance (n = 10) and average follow-up of 12.4 months. The most common primary cancers were prostate (n = 3) and lung (n = 3). The average time from cancer diagnosis to clival metastasis was 34 months. The most common presenting symptoms were headache (n = 9) and diplopia (n = 7). Five patients presented with abducens nerve palsies, and two presented with oculomotor nerve palsies. The median tumor volume was 9.3 cc, and the median margin dose was 15 Gy. Eleven patients achieved tumor control after one procedure, and three with progression obtained tumor control after repeat GKRS. One patient recovered abducens nerve function. The median survival from cancer diagnosis and GKRS were 49.7 and 15.3 months, respectively. The cause of death was progression of systemic cancer in six patients, clival metastasis in one, and unknown in four. The systematic review included 31 studies with heterogeneous descriptions of treatment and outcomes. CONCLUSION: Clival metastasis is rare and associated with poor prognosis. GKRS is a safe, effective treatment for clival metastasis.