Cranial and Spinal Cerebrospinal Fluid Leaks: Foundations of Identification and Management.

Cerebrospinal fluid (CSF) leaks may occur at the skull base or along the spinal column and can cause a variety of debilitating neurological symptoms for patients. Recognizing the potential presence of a CSF leak and then identifying its source are necessary for accurate diagnosis and definitive treatment. A standardized workflow can be followed for successful leak localization, which often requires several diagnostic studies, and for definitive leak treatment, which can range from minimally invasive, needle-based approaches to a variety of surgical corrections. This review paper provides an overview of epidemiology, pathophysiology, and diagnostic workup for CSF leaks and introduces available treatment options. An illustrative case of a skull base CSF leak demonstrating diagnosis and surgical correction is provided.

Orbital Cerebrospinal Fluid Leak After Dog Bite: A Case Report

A 4-year-old boy was referred to our tertiary hospital after a penetrating adnexal injury by a large-breed dog to the left orbital area. There was an increase in lacrimation, which was thought to be due to an inflammatory reaction. However, it was discovered that the lacrimation increased in the reverse-Trendelenburg position and with the Valsalva maneuver. Halo sign and beta transferrin test were positive, which led to the diagnosis of cerebrospinal fluid (CSF) fistula, and the patient was operated using a supraorbital craniotomy. A dural tear was visualized and sutured appropriately, then fibrin glue and an autologous galeal graft were applied to the tear. The CSF oculorrhea stopped postoperatively, and the patient was discharged after 10 days of follow-up. The patient had no recurrent CSF leakage at 4-year follow-up. Although CSF oculorrhea is rare and may be difficult to discern from lacrimation, the presence of pneumocephalus and halo sign should suggest fistula repair.

Conventional clinical signs and symptoms are poor predictors of postoperative cerebrospinal fluid leak: A single-centre cohort perspective.

BACKGROUND: Postoperative cerebrospinal fluid (CSF) leak remains a concerning complication of the endoscopic endonasal approach (EEA) for skull base pathology. Signs and symptoms suggesting CSF leak often trigger additional workup during the postoperative course. We systematically evaluate associations between subjectively reported clinical signs/symptoms noted during the immediate postoperative period and incidence of postoperative CSF leaks. METHODS: Retrospective chart review was conducted at a tertiary academic medical centre including 137 consecutive patients with intraoperative CSF leak during EEA with primary repair between July 2018 and August 2022. Postoperative CSF leak associations with clinical signs and symptoms were evaluated using positive (PPV) and negative predictive values (NPV), sensitivity, specificity and odds ratio (OR) via univariate logistic regression. RESULTS: Seventy-nine patients (57.7%) had high-flow leaks repaired and 5 (3.6%) developed CSF leaks postoperatively. Of reported symptoms, rhinorrhea was most common (n = 52, 38.0%; PPV [95% CI] = 7.6% [4.8%, 11.9%]), followed by severe headache (n = 47, 34.3%; 6.3% [3.1%, 12.5%]), dizziness (n = 43, 31.4%; 2.3% [0.4%, 12.1%]), salty or metallic taste (n = 20, 14.6%; 9.9% [3.3%, 25.8%]), and throat drainage (n = 10, 7.3%; 9.9% [1.7%, 41.4%]). Nausea or vomiting constituted the most reported sign concerning for CSF leak (n = 73, 53.3%; PPV [95% CI] = 4.1% [2.0%, 8.1%]). On univariate regression, no sign or symptom, including rhinorrhea (OR [95% CI] = 7.00 [0.76-64.44]), throat drainage (3.42 [0.35-33.86]), salty/metallic taste (4.22 [0.66-27.04]), severe headache (3.00 [0.48-18.62]), dizziness (0.54 [0.06-4.94]), fever (3.16 [0.50-19.99]), and nausea/vomiting (1.33 [0.22-8.21]), associated with postoperative CSF leak. CONCLUSIONS: A range of subjectively reported symptoms and signs failed to predict postoperative CSF leak. Further investigation is warranted to inform appropriate attention and response.

Development and Clinical Validation of a Hook Effect-Based Lateral Flow Immunoassay Sensor for Cerebrospinal Fluid Leak Detection.

BACKGROUND AND OBJECTIVES: Rapid detection of cerebrospinal fluid (CSF) leaks is vital for patient recovery after spinal surgery. However, distinguishing CSF-specific transferrin (TF) from serum TF using lateral flow immunoassays (LFI) is challenging due to their structural similarities. This study aims to develop a novel point-of-care diagnostic assay for precise CSF leak detection by quantifying total TF in both CSF and serum. METHODS: Capitalizing on the substantial 100-fold difference in TF concentrations between CSF and serum, we designed a diagnostic platform based on the well-known "hook effect" resulting from excessive analyte presence. Clinical samples from 37 patients were meticulously tested using the novel LFI sensor, alongside immunofixation as a reference standard. RESULTS: The hook effect-based LFI sensor exhibited outstanding performance, successfully discriminating positive clinical CSF samples from negative ones with remarkable statistical significance (positive vs negative t -test; P = 1.36E-05). This novel sensor achieved an impressive 100% sensitivity and 100% specificity in CSF leak detection, demonstrating its robust diagnostic capabilities. CONCLUSION: In conclusion, our study introduces a rapid, highly specific, and sensitive point-of-care test for CSF leak detection, harnessing the distinctive TF concentration profile in CSF compared with serum. This novel hook effect-based LFI sensor holds great promise for improving patient outcomes in the context of spinal surgery and postsurgical recovery. Its ease of use and reliability make it a valuable tool in clinical practice, ensuring timely and accurate CSF leak detection to enhance patient care.

The cervical blood patch: A therapeutic "miraculous" for cerebrospinal fluid leaks: A case report.

RATIONALE: Cerebrospinal fluid (CSF) leaks, arising from abnormal openings in the protective layers surrounding the spinal cord and brain, are a significant medical concern. These leaks, triggered by various factors including trauma, medical interventions, or spontaneous rupture, lead to the draining of CSF-an essential fluid safeguarding the nervous system. A classic symptom of CSF leaks is an incapacitating headache exacerbated by sitting or standing but relieved by lying down. Spontaneous intracranial hypotension (SIH) denotes the clinical condition marked by postural headaches due to spontaneous CSF leakage and hypotension, often misdiagnosed or underdiagnosed. While orthostatic headaches are the hallmark, SIH may manifest with an array of symptoms including nausea, tinnitus, hearing loss, visual disturbances, and dizziness. Treatment options encompass conservative measures, epidural blood patches (EBP), and surgery, with EBP being the primary intervention. PATIENT CONCERN: The patient did not express any specific concerns regarding their medical diagnosis. However, they did harbor apprehensions that their condition might necessitate surgical intervention in the future. DIAGNOSIS: The patient had been treated with antibiotics with a pre-diagnosis of sinusitis and was admitted to the neurology department of our hospital when his symptoms failed to improve. Cranial magnetic resonance imaging was interpreted as thickening of the dural surfaces and increased contrast uptake, thought to be due to intracranial hypotension. Cranial MR angiography was normal. Full-spine magnetic resonance imaging revealed a micro-spur at the C2 to 3 level and the T1 to 2 level in the posterior part of the corpus. INTERVENTIONS: The cervical EBP was performed in the prone position under fluoroscopic guidance. There were no complications. OUTCOMES: The patient was invited for follow-up 1 week after the procedure, and control examination was normal. LESSONS: SIH poses a diagnostic challenge due to its diverse clinical presentation and necessitates precise imaging for effective intervention. Cervical EBP emerges as a promising treatment modality, offering relief and improved quality of life for individuals grappling with this condition. However, clinicians must carefully assess patients and discuss potential risks and benefits before opting for cervical blood patches.

Spontaneous Cerebrospinal Fluid Leak in a Patient with Asymptomatic Idiopathic Intracranial Hypertension.

BACKGROUND: Spontaneous cerebrospinal fluid (CSF) leaks occur when there is a tear in the dura mater. Spontaneous CSF leaks are rare, and often associated with conditions like intracranial hypertension, connective tissue disorders, or congenital defects in the dura mater. CASE REPORT: The patient was a 66-year-old woman who presented to the Emergency Department with clear, positional nasal discharge from her left nostril for 1 week. She had a history of chronic headaches, which seemed to have been relieved around the time of onset of her rhinorrhea. Diagnostic imaging, including computed tomography and magnetic resonance imaging scans, confirmed the presence of a CSF leak and a left temporal meningoencephalocele. The patient subsequently underwent surgical repair of the leak and ventriculoperitoneal shunt placement, and was discharged home in stable condition. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Early detection of CSF leaks require a thorough history and physical examination, and is crucial in preventing potentially life-threatening complications such as meningitis and intracranial abscesses.

Cerebrospinal Fluid Refill Test as a Novel Diagnostic Tool for Cerebrospinal Fluid Hypovolemia: Preliminary Result.

OBJECTIVE: Cerebrospinal fluid (CSF) hypovolemia presents with orthostatic headaches due to CSF leakage. However, a direct association between the lack of CSF and clinical symptoms has not been found. CSF hypovolemia can be improved by refilling CSF. Therefore, we assessed the validity of a CSF refill test. METHODS: From November 2019 to August 2021, we included 10 patients (≥18 years old) with potential CSF hypovolemia, clear orthostatic headaches, and a CSF opening pressure <10 cmH2O. In the CSF refill test, 10 mL of artificial CSF was injected intrathecally. The primary outcome was improvement in orthostatic headache assessed using a visual analog scale (VAS), while the secondary outcomes were the 10-m walk time and adverse events. When the symptoms temporarily improved after intrathecal injection, the patients underwent radiologic imaging to identify the CSF leak, and an epidural blood patch was proposed accordingly. RESULTS: All patients showed post-test improvements in the VAS score (median [interquartile range], pretest 63.0 [50.3-74.3] vs. post-test 1.5 [0.0-26.0]). The 10-m walk time also significantly improved (9.5 [8.5-10.2] s vs. 8.2 [7.9-8.7] s). One patient experienced temporary right leg numbness associated with a lumbar puncture. After radiologic investigation, 9 patients underwent epidural blood patches, of which 6 were completely cured, and 3 revealed partial improvement. CONCLUSIONS: The cerebrospinal fluid (CSF) refill test was safe and effective in demonstrating the direct association between the lack of CSF and clinical symptoms and may help predict the outcome of an epidural blood patch.

A new modified technique of dynamic CT myelography to detect dural tears in spontaneous intracranial hypotension.

We propose a modified dynamic CT-myelography technique for patients with fast CSF leaks caused by ventral dural tears in order to reduce radiation exposure and complications. A fluoroscopy-guided lumbar puncture using an epidural anesthesia kit replaces a CT-guided lumbar puncture, and a smaller volume of less concentrated contrast media is used. This approach has advantages, including speeding up the procedure, reduced radiation exposure, and elimination of the risk of contrast injection into the epidural space.

Multiple skull base defects in the setting of spontaneous cerebrospinal fluid rhinorrhea; a dual institution view.

PURPOSE: Idiopathic intracranial hypertension (IIH) is a condition of high cerebrospinal fluid (CSF) pressure that presents with CSF leak. The implications of multiple skull base defects (SBD) and associated synchronous CSF leaks have not been previously explored. MATERIALS AND METHODS: A dual institutional case-control study examined multiple SBD's and encephaloceles on the risk of CSF leak and postoperative failures post-repair. IIH patients with CSF leaks and IIH controls without leaks were selected retrospectively. Chi square analysis evaluated for statistically significant alterations in probability with CSF leak development. RESULTS: 192 patients were selected with 108 IIH controls and 84 spontaneous CSF leak cases. Signs and symptoms for IIH controls and CSF leak cases respectively were pulsatile tinnitus (60.2 % and 29.8 %), headaches (96.3 % and 63.1 %), papilledema (74.1 % and 12.5 %), visual field defects (60.8 % and 13 %) (p < 0.001). Encephalocele formation in controls was 3.7 % compared to cases at 91.6 % (p < 0.001). Multiple SBD's in controls compared cases was 0.9 % and 46.4 % respectively (p < 0.001). Subgroup analysis of CSF leak cases showed 15 patients with two CSF leak repairs due to a recurrence. 27 (39.1 %) single leak cases had multiple SDB's while 12 (80 %) recurrent leaks had multiple SDB's (p = 0.004). CONCLUSIONS: Patients with radiographic evidence of multiple SBD's and encephaloceles represent a high-risk population with a propensity for CSF leaks. Secondary SBD's are common in patients with spontaneous CSF rhinorrhea and higher in patients with a recurrence.

[SPONTANEOUS CEREBROSPINAL FLUID LEAK OF THE TEMPORAL BONE].

INTRODUCTION: Spontaneous cerebrospinal fluid (CSF) leak into the temporal air spaces is a prominent risk factor for meningitis, often leading to debilitating neurological morbidities and even death. CSF leaks may arise due to trauma, congenital malformation, or surgery, but in most cases, they develop spontaneously. In spontaneous CSF leaks, no obvious triggering event is apparent in the patient's clinical history that points to this diagnosis, in contrast to some of the other etiologies. The clinical presentation of spontaneous CSF leaks is not unique and is characterized by patients' complaints, such as hearing loss and aural fullness. These symptoms are commonly associated with prevalent conditions, such as serous otitis media. For these reasons, a typical diagnostic delay of spontaneous CSF leaks, which can last for years in some cases, leaves the patients exposed to meningeal infection without being offered an efficient surgical treatment to keep them safe and protected.

Case Report: Unilateral Cranial Nerve VI Palsy Secondary to Intracranial Hypotension.

SIGNIFICANCE: Intracranial hypotension is a condition that occurs from a cerebrospinal fluid leak. Various visual symptoms have been associated with this condition. Cranial nerve VI (CN VI) palsies are the most common ocular manifestation, as the abducens nerve is prone to injury because of its intracranial anatomical course. PURPOSE: This case report presents a CN VI palsy secondary to intracranial hypotension from ventriculoperitoneal shunt overfiltration. Diagnosis, treatment, and management considerations are discussed. No identifiable health information was included in this case report. CASE REPORT: A 70-year-old White man was referred to the eye clinic for evaluation of binocular horizontal diplopia. The patient had a recent history of a left ventriculoperitoneal shunt for a persistent cerebrospinal fluid leak after complex mastoid surgery. The patient was also symptomatic for positional headaches, which improved in a recumbent position. He was diagnosed with a left CN VI palsy secondary to intracranial hypotension from a ventriculoperitoneal shunt overfiltration. The patient was followed up by neurosurgery for shunt adjustments to resolve the overfiltration. Binocular horizontal diplopia was managed conservatively with Fresnel prism. CONCLUSIONS: Intracranial hypotension should be considered in patients presenting with cranial nerve palsies and positional headaches. Obtaining neuroimaging and comanaging with neurology or neurosurgery are advised to make prompt diagnosis and treatment. Careful clinical monitoring and conservative diplopia therapy are recommended as visual symptoms improve upon resolution of the cerebrospinal fluid leak.

Multidisciplinary consensus guideline for the diagnosis and management of spontaneous intracranial hypotension.

BACKGROUND: We aimed to create a multidisciplinary consensus clinical guideline for best practice in the diagnosis, investigation and management of spontaneous intracranial hypotension (SIH) due to cerebrospinal fluid leak based on current evidence and consensus from a multidisciplinary specialist interest group (SIG). METHODS: A 29-member SIG was established, with members from neurology, neuroradiology, anaesthetics, neurosurgery and patient representatives. The scope and purpose of the guideline were agreed by the SIG by consensus. The SIG then developed guideline statements for a series of question topics using a modified Delphi process. This process was supported by a systematic literature review, surveys of patients and healthcare professionals and review by several international experts on SIH. RESULTS: SIH and its differential diagnoses should be considered in any patient presenting with orthostatic headache. First-line imaging should be MRI of the brain with contrast and the whole spine. First-line treatment is non-targeted epidural blood patch (EBP), which should be performed as early as possible. We provide criteria for performing myelography depending on the spine MRI result and response to EBP, and we outline principles of treatments. Recommendations for conservative management, symptomatic treatment of headache and management of complications of SIH are also provided. CONCLUSIONS: This multidisciplinary consensus clinical guideline has the potential to increase awareness of SIH among healthcare professionals, produce greater consistency in care, improve diagnostic accuracy, promote effective investigations and treatments and reduce disability attributable to SIH.

Relationship of Bern Score, Spinal Elastance, and Opening Pressure in Patients With Spontaneous Intracranial Hypotension.

BACKGROUND AND OBJECTIVES: Existing tools to diagnose spontaneous intracranial hypotension (SIH), namely spinal opening pressure (OP) and brain MRI, have limited sensitivity. We investigated whether evaluation of brain MRI using the Bern score, combined with calculated craniospinal elastance, would aid in diagnosing SIH and provide insight into its pathophysiology. METHODS: A retrospective chart review was performed of patients who underwent brain MRI and pressure-augmented dynamic CT myelography (dCTM) for suspicion of SIH. Two blinded neuroradiologists assigned Bern scores for each brain MRI. OP and incremental pressure changes after intrathecal saline infusion were recorded to calculate craniospinal elastance. The relationship between Bern score, OP, and elastance and whether a leak was found were analyzed. RESULTS: Seventy-two consecutive dCTMs were performed in 53 patients. Twelve CSF-venous fistulae, 2 ruptured meningeal diverticula, 2 dural defects, and 1 dural bleb were found (17/53, 32%). Among patients with imaging-proven CSF leak/fistula, OP was normal in all but 1 patient and was not significantly different in those with a leak compared with those without (15.1 vs 13.6 cm H2O, p = 0.24, A = 0.40). The average Bern score in individuals with a leak was significantly higher than that in those without (5.35 vs 1.85, p < 0.001, A = 0.85), even when excluding pachymeningeal enhancement from the score (3.77 vs 1.57, p = 0.001, A = 0.78). The average elastance in those with a leak was higher than that in those without, but this difference was not statistically significant (2.05 vs 1.20 mL/cm H2O, p = 0.19, A = 0.40). Increased elastance was significantly associated with an increased Bern score (95% CI -0.55 to 0.12, p < 0.01) and was significantly associated with venous distention, pachymeningeal enhancement, prepontine narrowing, and subdural collections, but not a narrowed mamillopontine or suprasellar distance. DISCUSSION: OP is not an effective predictor for diagnosing CSF leak and if used in isolation would result in misdiagnosis of 94% of patients in our cohort. The Bern score was associated with a higher diagnostic yield of dCTM. Elastance was significantly associated with certain components of the Bern score.

Cerebrospinal Fluid Leaks, Spontaneous Intracranial Hypotension, and Chiari I Malformation.

Spontaneous intracranial hypotension (SIH) occurs secondary to cerebrospinal fluid (CSF) hypovolemia in the setting of noniatrogenic spinal CSF leak. Although orthostatic headache is characteristic, atypical presentations can occur. Cranial imaging can disclose characteristic imaging features of SIH but spinal imaging is needed for leak localization. Although advanced diagnostic workup and treatment depend on the type of CSF leak, differentiation of SIH from other headache pathologic conditions, such as Chiari I malformation, is crucial to prevent misdiagnosis and ineffective treatment.

Expanding the clinical spectrum of idiopathic intracranial hypertension.

PURPOSE OF REVIEW: Idiopathic intracranial hypertension (IIH) is a disorder of raised intracranial pressure (ICP). Although the majority of patients with IIH present classically with headache and papilledema, some patients may have unusual presentations or manifestations. Recent advancements in neuroimaging have facilitated the identification of other presentations associated with IIH. This review provides an overview of the expanding clinical spectrum of IIH. RECENT FINDINGS: Presentations of IIH that are considered unusual include highly asymmetric or unilateral papilledema, IIH without papilledema, and IIH associated with cranial nerve involvement. These presentations likely reflect differences in the way cerebrospinal fluid (CSF) pressure is transmitted intracranially. Radiological signs of intracranial hypertension are increasingly recognized in patients with IIH and provide further insights into the effects of raised ICP on intracranial structures. Osseous changes in the skull base leading to formation of meningoceles and encephaloceles have been identified in patients with IIH, spontaneous skull base CSF leak, and drug-resistant temporal lobe epilepsy, suggesting a possible association. SUMMARY: Clinicians should be familiar with the expanding clinical spectrum of IIH and the implications for the management of these presentations.

Spontaneous intracranial hypotension: updates from diagnosis to treatment.

Spontaneous intracranial hypotension (SIH) is caused by spinal cerebrospinal fluid (CSF) leaks, which result in continued loss of CSF volume and multiple debilitating clinical manifestations. The estimated annual incidence of SIH is 5/100,000. Diagnostic methods have evolved in recent years due to improved understanding of pathophysiology and implementation of advanced myelographic techniques. Here, we synthesize recent updates and contextualize them in an algorithm for diagnosis and treatment of SIH, highlighting basic principles and points of practice variability or continued debate. This discussion includes finer points of SIH diagnosis, CSF leak classification systems, less common types and variants of CSF leaks, brain MRI Bern scoring, potential SIH complications, key technical considerations, and positioning strategies for different types of dynamic myelography. The roles of conservative measures, non-targeted or targeted blood patches, surgery, and recently developed endovascular techniques are presented.

Presumptive Idiopathic Intracranial Hypertension Based on Neuroimaging Findings: A Referral Pattern Study.

BACKGROUND: Radiologic findings of intracranial hypertension (RAD-IH) are common in idiopathic intracranial hypertension (IIH) patients. Paralleling the increasing rates of obesity, the burden of IIH is growing. Urgent neuro-ophthalmology consultations for possible IIH in patients with incidentally detected RAD-IH are increasing, with many patients receiving unnecessary lumbar punctures (LPs) and treatments. This retrospective observational study aimed to determine the prevalence of neuro-ophthalmology consultations for RAD-IH, rate of funduscopic examination by referring providers, prevalence of papilledema, outcomes after neuro-ophthalmic evaluation, and rates of misdiagnosis. METHODS: Records of 1,262 consecutive new patients seen in one neuro-ophthalmology clinic from January 2019 to January 2020 were reviewed. We identified patients who were: 1) referred with concern for IIH because of findings of RAD-IH; 2) referred for "papilledema"; 3) referred with a diagnosis of IIH; and 4) referred for spontaneous cranial cerebrospinal fluid (CSF) leaks. In addition to basic demographic profiles for all groups, detailed information was collected for patients referred solely for RAD-IH, including referral patterns, prior history of IIH, previous LPs, prior medical or surgical treatment(s), risk factors for increased intracranial pressure (ICP), presenting symptoms, radiologic features observed on neuroimaging, and final disposition. When available, the neuroimaging was reviewed by an expert neuroradiologist. RESULTS: Of 1,262 consecutive new patients, 66 (5%) were referred specifically for RAD-IH; most referrals came from neurologists (58%); 8/66 (12%) patients had papilledema; 16/66 (24%) patients had prior LP and 13/66 (20%) were already treated based on MRI findings; and 22/66 (33%) patients had ≤2 RAD-IH. Only 34/66 (52%) of patients referred for RAD-IH had prior funduscopic examinations. We confirmed papilledema in 26/82 (32%) patients referred for "papilledema." Only 29/83 (35%) patients referred with a diagnosis of IIH had active papilledema, and 3/16 (19%) patients with spontaneous CSF leaks had papilledema. In total, 247/1,262 (20%) new patients were referred to our clinic over 1 year with concern for IIH, among whom only 66 (27%) were confirmed to have active IIH with papilledema. CONCLUSIONS: One in 5 new patient referrals seen in our neuro-ophthalmology clinic were referred because of concern for increased ICP, but only 1/4 had active papilledema. Most patients referred for isolated RAD-IH do not have papilledema, many having undergone unnecessary LPs and treatments. The burden of these "rule-out IIH" consultations is overwhelming and will only continue to increase with the concurrent rise of obesity and IIH, straining the already limited neuro-ophthalmologic resources available in the US.

A supervised machine-learning algorithm predicts intraoperative CSF leak in endoscopic transsphenoidal surgery for pituitary adenomas.

BACKGROUND: Despite advances in endoscopic transnasal transsphenoidal surgery (E-TNS) for pituitary adenomas (PAs), cerebrospinal fluid (CSF) leakage remains a life-threatening complication predisposing to major morbidity and mortality. In the current study we developed a supervised ML model able to predict the risk of intraoperative CSF leakage by comparing different machine learning (ML) methods and explaining the functioning and the rationale of the best performing algorithm. METHODS: A retrospective cohort of 238 patients treated via E-TNS for PAs was selected. A customized pipeline of several ML models was programmed and trained; the best five models were tested on a hold-out test and the best classifier was then prospectively validated on a cohort of 35 recently treated patients. RESULTS: Intraoperative CSF leak occurred in 54 (22,6%) of 238 patients. The most important risk's predictors were: non secreting status, older age, x-, y- and z-axes diameters, ostedural invasiveness, volume, ICD and R-ratio. The random forest (RF) classifier outperformed other models, with an AUC of 0.84, high sensitivity (86%) and specificity (88%). Positive predictive value and negative predictive value were 88% and 80% respectively. F1 score was 0.84. Prospective validation confirmed outstanding performance metrics: AUC (0.81), sensitivity (83%), specificity (79%), negative predictive value (95%) and F1 score (0.75). CONCLUSIONS: The RF classifier showed the best performance across all models selected. RF models might predict surgical outcomes in heterogeneous multimorbid and fragile populations outperforming classical statistical analyses and other ML models (SVM, ANN etc.), improving patient management and reducing preventable morbidity and additional costs.

Systematic Review: Evaluating the Efficacy of Intrathecal Fluorescein for Localizing Cerebrospinal Fluid Rhinorrhea.

OBJECTIVES: A defect in the skull base can result in leakage of cerebrospinal fluid (CSF) out of the subarachnoid space into the sinonasal cavities, termed CSF rhinorrhea. Patients presenting with CSF rhinorrhea often require surgical repair, typically performed endoscopically. Successful surgical intervention is highly reliant on accurate identification of the leak site. Identification can be enhanced by the administration of intrathecal fluorescein (IF) via a lumbar drain before surgery. The objective of this systematic review is to better characterize the benefits and limitations of IF administration. METHODS: A systematic search was conducted for literature documenting the use of IF for CSF leak localization. The results of this search were subjected to initial review, followed by full-text evaluation of selected texts, and final inclusion based on predetermined selection criteria. Primary outcomes were specificity and sensitivity of IF administration in identifying CSF leak sites. Secondary outcomes included administration technique and safety data. RESULTS: A total of 25 studies representing 3801 instances of IF administration met inclusion criteria. When injected slowly for up to 30 minutes at doses of <50 mg, IF administration results in minimal complications. A total of 25 mg doses (92.36%) of IF appear more sensitive than 10 mg (71.88%) doses of IF while maintaining a similar safety profile. Mixing fluorescein with double distilled water instead of CSF or saline may decrease waiting times before fluorescein can be identified and increase its safety profile. CONCLUSIONS: Intrathecal fluorescein may play an important role in the identification of CSF leak site during endoscopic repair.