Background: Fluorescence-guided surgery (FGS) with 5-aminolevulinic acid (5-ALA) is a well-established tool for improving tumor visualization in glioma surgery. However, its applications in non-glioma pathologies remain underexplored and require further investigation. Methods: A retrospective review of patients who underwent FGS with 5-ALA between January 2022 and September 2024 was conducted to assess its utility in non-glioma tumors. Results: Among 232 FGS procedures, 13 (5.6%) involved non-glioma pathologies. We categorized our patients into three different levels: high, moderate, and no response based on intra-operative 5-ALA fluorescence visualization. Our patients showed a high 5-ALA fluorescence in 10 cases (77%), mainly in the following tumors: choroid plexus papilloma, atypical teratoid rhabdoid tumor, metastatic adenocarcinoma as well as atypical meningiomas. Moderate 5-ALA fluorescence was seen in 2 cases (15%). While no 5-ALA fluorescence was seen in one case of CNS lymphoma. 90% of procedures with high response had total resection. Conclusions: Fluorescence-guided surgery (FGS) using 5-ALA has demonstrated effectiveness in enhancing tumor visualization beyond gliomas. This retrospective review highlights the potential applications of 5-ALA in various non-glioma pathologies. These findings emphasize the need for further research to refine the use of 5-ALA FGS in diverse pathologies, optimize patient selection, and expand its utility in neurosurgical oncology.

Background: Surgical access to the clival region is challenging, but advanced endoscopic endonasal approaches (EEA) provide a minimally invasive corridor. This study aimed to review the clinical outcomes of patients who underwent EEA for skull base lesions involving the clivus and to analyze prognostic factors. Methods: A retrospective review was conducted of patients who underwent EEA for resection of clival lesions between October 2001 and October 2023. Data on demographics, approach type, reconstruction technique, tumor pathology and outcomes were collected. Results: Forty-six patients underwent transclival EEA. The majority had ASA scores II and III (71.7%), with clival chordomas being the most common pathology (37%). Cranial nerve impairment was present in 65% of patients, and 80% showed improvement post-surgery. The mean procedure duration was 308 minutes, with a mean blood loss of 424 mL. A lumbar drain was used in 10.9%, and 76.1% received a pedicled nasoseptal flap for reconstruction. Complete tumor resection was achieved in 74% of malignant cases. Postoperative CSF leaks occurred in 4.3%, and the mean length of stay was 12.2 days. Higher readmission rates were associated with ASA IV classification (p=0.006). Conclusions: EEA to the clival region is safe and effective, with low perioperative complications and high rates of postoperative improvement.

Background: This study aims to review the clinical outcomes, extent of resection, complications, and prognostic factors in patients undergoing endonasal endoscopic resection (EEA) of anterior cranial base meningiomas. Methods: We conducted a retrospective review of 25 patients who underwent EEA resection of these lesions between 2001 and 2023. We assessed the extent of resection, complications, postoperative outcomes, and key technical aspects of the procedure. Results: 84% of patients were classified as ASA class III. Additionally, 64% of patients presented with visual disturbances. The mean blood loss was 472 ml. Intraoperative lumbar drains were used in 40% of cases, and dural sealants in 56%. A pedicled nasal flap was employed for reconstruction in 92% of cases. One vascular injury was documented, and 16% of patients developed a cerebrospinal fluid (CSF) leak in the postoperative period The degree of resection varied according to tumor location. Prognostic factors for achieving gross total resection, functional improvement, and key factors for reconstruction are discussed. The rate of CSF leaks decreased dramatically in the later years of the series Conclusions: Cranial base meningiomas can be successfully managed via a purely endoscopic endonasal approach, with acceptable morbidity and mortality rates.

Background: Endonasal endoscopic odontoidectomy (EEO) is a well-established method for treating symptomatic ventral compression at the cranio-cervical junction (CCJ). This study aims to review the clinical outcomes of patients undergoing EEO, focusing on clinical presentation, progression, and prognostic factors. Methods: We retrospectively analyzed data from patients who underwent EEO between October 2001 and October 2023. Information was collected on demographics, indications, reconstruction techniques, complications, fusion requirements, readmission rates, and outcomes. Results: Fifteen patients were included, with 60% classified as ASA class III. The majority presented with myelopathy (80%). Indications for surgery included basilar invagination, Chiari malformation, and rheumatoid arthritis. The mean blood loss was 317 ml. No perioperative lumbar drains were used, and 26.7% of patients had intraoperative CSF leaks, though no postoperative leaks were noted. A pedicled nasal flap was required in 66.7% of cases. Fourteen patients needed occipitocervical fusion, and six were readmitted within 30 days due to bulbar deficits. At the last follow-up, 86.6% of patients experienced symptom improvement. A significant association was found between decompression extent and symptomatic improvement (p=0.003). Conclusions: EEO is a safe and effective method for CCJ decompression, often accompanied by posterior cervical stabilization, with most patients showing symptomatic improvement and a low complication rate.

Background: This study aimed to identify risk factors for postoperative cerebrospinal fluid (CSF) leaks and assess their outcomes following endoscopic endonasal approach (EEA) for resection of skull base tumors. Methods: A retrospective review was conducted of patients who underwent EEA for resection of intradural pathology between October 2001 and October 2023. Data on demographics, approach type, reconstruction technique, tumor pathology, complications and outcomes were analyzed. Results: A total of 542 patients were included, with 80.1% undergoing surgery for sellar or suprasellar pathology. Lumbar drains were used in 14.9%, and dural sealants in 57.7%. Forty patients (7.3%) developed postoperative CSF leaks, with the highest rate in sellar or suprasellar lesions (5.9%). CSF leaks were associated with longer hospital stays (p < 0.001), higher 30-day readmission rates (p < 0.001), increased sepsis risk (p = 0.021), and higher rates of diabetes insipidus (p < 0.001). Lumbar drains increased the incidence of CSF leaks (p = 0.021), while nasoseptal flap reconstruction reduced leak rates (p = 0.0015). Higher BMI and intraoperative CSF leaks were also significant risk factors (p = 0.001) Conclusions: CSF leaks are associated with increased complications and extended hospital stays, highlighting the need for vigilant intraoperative monitoring and targeted strategies.

Background: Postoperative visual deterioration following endoscopic endonasal surgery for pituitary adenoma is very rare yet significant morbidity. Visual deficit can arise from iatrogenic injury, compression or ischemic insults. The specific predictors of visual decline and their correlation with the effectiveness of various interventions remain poorly understood. Methods: We retrospectively reviewed data from790 patients who underwent endoscopic endonasal surgery for pituitary adenoma between 2014-2024. We included all the patients who had New Postoperative visual deterioration. Demographic, preoperative, intraoperative, postoperative data were collected and analyzed. Results: Nine patients (1.13%) experienced early postoperative visual deterioration. None of the patient has intraoperative report of direct injury to the optic apparatus, ischemic etiology was seen in five patients. Four patients underwent early reoperation to explore and decompress the optic apparatus. Vision was restored to baseline after reoperation in all 4 compressive cases. In the ischemic group (n=5), three patients improved with supplemental oxygen and hypervolemic-hypertensive therapy (p=0.03). Conclusions: Prognosis and outcome of Postoperative visual deterioration depends on the underlying cause and the effectiveness of intervention. Compressive etiology has a favorable prognosis when identified and managed with reoperation and decompression. Ischemic etiology potentially treatable with supplemental oxygen hypervolemic-hypertensive and high mean arterial pressure in more than half of cases.

Background: Biochemical cure in functional pituitary adenomas (FPA) is crucial for reducing patient morbidity and improving quality of life following endoscopic endonasal procedures (EEA). The extent of resection plays a key role in achieving these outcomes. However, even with the aid of intraoperative navigation, complete resection of tumor components can be challenging due to the difficulty in distinguishing them from normal pituitary tissue. Indocyanine green (ICG) fluorescence has been used effectively in various cranial and spinal procedures, but its role in endoscopic skull base surgery has not yet been routinely established Methods: In this study, we describe our experience using ICG during EEA for the resection of FPA. Results: We discuss the fluorescence profiles of both adenomas and normal gland tissue. ICG helped identify additional tumor tissue that was not initially detected after macroscopic adenoma resection. It also allowed for perfusion assessment of the pituitary gland and nasoseptal flaps. No complications were observed following the ICG injection, and biochemical cure was achieved in more than 90% of cases. Conclusions: Our experience suggests that ICG is a safe and promising tool, improving both the extent of resection and endocrinologic outcomes in patients undergoing EEA for FPA.

Background: Endoscopic endonasal surgeries performed in areas involving the visual pathway are associated with postoperative visual dysfunction. We previously demonstrated that continued eye monitoring during surgery by flash visual evoked potential (FVEP) represents a good method to prevent/reduce visual deficit post-surgery. We wondered whether FVEP monitoring may be more beneficial in patients with meningioma, strongly associated with postoperative visual loss.

The aim was to explore the visual capacity in patients subjected to meningioma resection at The Ottawa Hospital. Methods: A retrospective chart review of patients who underwent minimally invasive endoscopic skull base surgery and FVEP monitoring for meningioma resection (July 2018 to present) was conducted. Only patients with available pre- (up to 3 months) and post-surgery (1-9 months) visual evaluation were analyzed. Results: 40 eyes were included (20 patients). The median age was 61 years (range:43-84) and 90% of patients were female. The LogMAR visual acuity was not significantly modified post-surgery (from +0.25 to +0.21; p=0.7). Color vision (# errors reading Ishihara/16-plates) was not modified post-surgery (from 2.6 to 3.2; p=0.6). Visual field (Humphrey, 32-2) was not significantly modified post-surgery (from 78.1% to 81.9%; p=0.7). Conclusions: The prevention of visual pathway injury during surgery by FVEP monitoring prevents visual deficits after endoscopic meningioma resection.

Background: Pituitary tumor recurrence following endoscopic endonasal transsphenoidal surgery (EETS) has been reported widely. We evaluated a modified score using the SIPAP classification system, combining the suprasellar and paraseller extension scores of the pituitary tumor, to determine its impact on adenoma recurrence. Methods: A retrospective cohort study design with patient characteristics, tumor type, endocrine, operation, imaging data collected. Preoperative MRI images were reviewed and SIPAP classification applied. Postoperative data were extracted for the follow-up period available for each patient.The suprasellar score and the highest parasellar scoring from both sides were numerically summed in a bilateral suprasellar and parasellar (SaP) score and combined to make 4 grades. Results: 276 patients were identified, 56.5% of the cohort was male. The mean cohort age was 54 years old.The mean follow up period was 32 months. Patient perioperative tumor grade according to SaP classification and recurrence rate was: Grade 1: 11%: Grade 2: 10%; Grade 3: 15%; Grade 4: 22%. The results followed a pattern of logarithmic curve. Conclusions: The SaP classification was useful in determining the pituitary tumor expected recurrence following EETS. The advanced tumors had the highest recurrence rates. Use of the SaP score may allow for more accurate preoperative counselling of patients with pituitary adenoma.

Background: One of the rare but urgent presentations of a pituitary tumor is pituitary apoplexy. In this case series, we describe our experience regarding the cranial nerve recovery in patients with pituitary apoplexy following endoscopic endonasal transsphenoidal surgery (EETS). Methods: Retrospective cohort study with patient characteristics, tumor type, endocrine data, operation data collected. Postoperative data were extracted for the follow-up period available for each patient. Results: 15 pituitary apoplexy cases were identified. The cranial nerve deficits presented at admission were: visual deficit (33% patients); unilateral third nerve palsy (47% patients), unilateral sixth nerve palsy (27% patients). Postoperatively, 60% of patients with preoperative visual deficit had normal visual fields and the other 40% showed improvement. From those with oculomotor nerve dysfunction preoperatively, 43% have returned to normal nerve function and 57% presented improvement. 75% cases of abducens nerve palsy resolved postoperatively, while 25% showed improvement. Conclusions: Based on this series, surgical treatment should be offered to patients presenting with cranial nerve deficit in the setting of pituitary apoplexy. In this series, all cranial nerve deficits either returned to normal or improved following surgery. Though a small series, the presented results are superior to those reported in the literature for conservative management.

Background: Odontoidectomy for basilar invagination and craniovertebral junction pathology has traditionally been performed using a transoral route. However, the endoscopic endonasal approach to the anterior craniovertebral junction may offer safer and more effective access when compared to transoral approaches. Methods: This study is a retrospective chart review of all adult patients who underwent an endoscopic endonasal odontoidectomy at a single tertiary care center between January 2011 and May 2019. Results: Seventeen patients were included in the study. The median admission age was 67 years (range: 33-84 years) and 65% of the patients were female. One patient (1/17, 6%) had vertebral artery injury which was coiled with no neurological deficits, and 4 patients (4/17, 24%) had intraoperative CSF leaks with no postoperative leak. Fourteen patients (14/17, 82%) were extubated by POD 1. Three patients (3/17, 18%) developed postoperative sinus infections and required antibiotics. Eight patients (8/17, 47%) developed transient postoperative dysphagia. One patient (1/17, 6%) had postoperative epistaxis and one patient (1/17, 6%) had postoperative lower cranial nerve symptoms. The median length of hospital stay was 13 days (range: 2-44 days). Conclusions: Endoscopic endonasal odontoidectomy is a feasible and well-tolerated procedure for anterior decompression of craniovertebral junction, associated with satisfactory patient outcomes and low morbidity.

Background: The surgical treatment of pituitary tumour has undergone substantial changes over time. In this study we evaluated our institutional results for pituitary tumour surgery using the endoscopic endonasal trans-sphenoidal (EETS) approach. Methods: Patient demographic, clinical and surgical data were extracted from medical records. Preoperative MRI images were reviewed. The SIPAP classification was applied to the pituitary tumors. Chi2 test and t test were used for statistical analysis. Results: 202 cases were identified. Functional tumors were present in 29% of the cohort. Patients with a suprasellar or parasellar SIPAP score of 0 or 1 had complete resection of their tumor in 66.6% of cases, compared to 29% with a suprasellar or parasellar SIPAP score ≥ 2 (Risk Ratio 2.3 CI 1.58-3.39, p=0.0005). When the tumor was completely resected radiologically, the mean time to recurrence was not different for the SIPAP 0 or 1 group which was 27 months in comparison to 34 months for the group with a SIPAP score 2 (p=0.13). Conclusions: Our study results showed that the preoperative MRI SIPAP score can be used to better inform patients about their expected outcomes of EETS.

Background: The surgical treatment of pituitary adenoma has evolved greatly over the decades. In order to better understand the patient population and their surgical treatment, we conducted an institutional review for pituitary adenoma surgery using the endoscopic endonasal trans-sphenoidal (EETS) approach. Methods: A retrospective review of all EETS cases for pituitary tumor resection was performed between November 2009 and June 2016. Patient characteristics, tumor type, endocrine data, operation characteristics were extracted from medical records. Preoperative MRI images were reviewed. The SIPAP classification was applied to the pituitary tumors. Postoperative patient data were extracted for the available follow-up period. Results: 232 cases were identified. Functional tumors were present in 29% of the cohort. Complete excision was most common for functioning tumors (49%) compared to nonfunctioning tumors (26%). There were no major vascular injuries. Hormone replacement with cortisol was required transiently in 70% of patients, with thyroid hormone replacement occurring in 40% of the cohort. Conclusions: From this large North American cohort nearly 30% of operated pituitary tumors were functioning. More commonly, these tumors were completely resected compared to the nonfunctioning group. The most commonly replaced hormone following EETS surgery was cortisol and this was largely transient.

Background: Traditionally petrous apex lesions surgical approach is associated with multiple complications including brain injury secondary to brain retraction. Expanded endoscopic endonasal trans-clival (EEET) can be used in selected patients with minimal complications. Methods: We are presenting our experience over the last three years in patients who underwent EEET resection of petrous apex lesions: 8 patients underwent such procedure. All patients underwent extensive workup including MRI and CTA to identify the relation of the carotid to the lesion. All surgeries were done with neuro-physiological monitoring. Intraoperative neuronavigation and endoscopic Doppler were used to identify the petrous segment of the internal carotid artery. Our follow up ranged from 6 months to 2.5 years. Results: All patients presented with severe neurologic symptoms related to either fifth cranial nerve, sixth cranial nerve or brain stem compression. Pathologies included chondrosarcoma, cholesterol granulomas and lymphangioma. All patients demonstrated improvement in their symptoms. None of our patients had intra-operative vascular injury. There was no post-operative CSF leak or infection. Postoperative imaging demonstrated excellent resection with no clear residual. Three patient required adjuvant stereotactic radiosurgery because of their underlying pathology. Conclusions: The expanded endoscopic endonasal approach for petrous apex lesion should be considered as a minimally invasive approach in selected cases.

Background: The benefit of prophylactic antibiotic use in endoscopic endonasal transsphenoidal surgery (EETS) for pituitary lesions is controversial. Many surgeons administer antibiotics perioperatively not based on clear guidelines but “to be safe”. Methods: A systematic review using PRISMA guidelines was performed to assess the efficacy of perioperative antibiotic use to prevent infectious complications in patients undergoing EETS. Inclusion criteria: randomized controlled trials, systematic reviews, observational studies, and case series. Data extracted: study design, year of publication, sample size, surgery type, perioperative antibacterial treatment (antibiotic, dose, and duration), number of patients with 30-days post-operative meningitis and/or sinusitis. End points: rates of meningitis and sinusitis post-EETS. Results: A total of 280 articles were identified. Four observational studies met inclusion criteria. Based on GRADE score these studies were considered low in quality. 633 patients were -included in those studies. The most common antibiotics used were cefazolin and ceftazidime. The rate of infection ranged from 0.5% to 3.1 % for meningitis as the most common infection. Conclusions: The need to use antibiotic(s) perioperatively is not clear in patients with pituitary lesions undergoing EETS. Randomized control trials are needed to evaluate the efficacy of prophylactic antibiotic use in patients with pituitary lesions undergoing EETS.

Background: Optic nerve/chiasmal injury is a devastating outcome that may happen during endoscopic surgery. Additionally, one of the goals of endoscopic skull-base surgery is visual improvement, currently there is limited ability of intraoperative visual pathway monitoring. We examine a novel technique using continuous flash visual evoked potentials (FVEPs). Methods: Eyes were stimulated by light stimulators (3 LEDs on each side, 640 nm peak wavelength, 10 ms pulse width, 3000 mCd of luminous intensity). Uniform illumination was placed over eyelids. Recording electrodes were placed at Oz-Fz. The filter cuts were ≤5 Hz and 100 Hz with amplifier gain 20,000 or 50,000. EEG was recorded. Recordings were correlated to pre and post operative VFs and acuity. Droop in the FVEP was examined in relation to intraoprative events. Results: Thirty patients had FVEPs in addition to other neurophysiologic monitoring. Patients demographic data, co-morbidities, diagnosis, surgical approach, length of surgery, MAP, and blood loss during surgery were recorded. All patients’ visual acuity and field deficits were evaluated by neuro-opthalmologist before their surgery and within 30 days after surgery. Conclusions: FVEP is reproducible throughout surgery and can predict the post surgical outcome. Additionally, we found that FVEP is transiently affected by different stages of surgery. Also boluses of propofol and electrocautery can artificially affect FVEP.

Background: patients with ventral cervical-medullary compression require anterior decompression of the cervicomedullary junction. Odontoid resection can be accomplished through expanded endoscopic approach especially in cases of irreducible basilar invagination in which the pathology is situated well above the palatine line. Methods: We are presenting our experience at the Ottawa Hospital (TOH) over the last seven years in patients who underwent expanded endoscopic endonasal decompression of their cervicomedullary junction. 16 patients underwent such procedure, those patients with preoperative cervical instability underwent posterior fusion for stabilization at the same surgical setting. Follow up ranged from 9 months to 5 years. Results: All patients had severe symptoms of myelopathy and some lower cranial nerves dysfunction. All patients were extubated after recovery from anesthesia and allowed oral intake next day. patients demonstrated improvement in their symptoms and none of them required tracheostomy. 12.5% experienced transient velopharyngeal insufficiency. one patient had CSF leak which was successfully treated with lumbar drain and one patient developed infection from the posterior cervical fusion and required debridement. All patients were eventually discharged home. Postoperative imaging demonstrated excellent decompression of the anterior cervicomedullary junction pathology. Conclusions: The expanded endoscopic endonasal approach for odontoidectomy should be considered as a minimally invasive approach for anterior decompression in selected cases