Comparative Cross Sectional Prospective Study of Anterior Skull Base Thickness in Spontaneous Cerebrospinal Fluid Rhinorrhoea vs Matched Controls.

Cerebrospinal fluid (Csf) leak is the leakage of CSF from subarachnoid space into the nasal cavity.Csf rhinorrhoea is classified as traumatic and non traumatic causes (Ommaya et al. J Neurol Neurosurg Psychiatry 31(3):214, 1968). Spontaneous csf leaks occur due to increased intracranial pressure. Early diagnosis of spontaneous csf leaks may prevent complications like meningitis. This was a cross sectional prospective study done in a tertiary care hospital. Group A-spontaneous csf leak patients and Group B- Non csf leak matched controls. The anterior skull base thickness from fovea ethmoidalis, cribriform plate and lateral lamella were compared between the groups using high resolution computed tomography of paranasal sinus with 2 mm cuts. The anterior skull base thickness was measured by a senior radiologist in our tertiary centre. In this study, total of forty six patients were included, twentythree in each group. The Mean age in Group A and Group B was 48.95 and 48.78 respectively. Body mass index (BMI) was compared between the two groupsand spontaneous csf leak patients had higher value than non csf leak controls. The mean anterior skull base thickness of Group A (cribriform plate-0.56 mm, lateral lamella-0.66 mm, Fovea ethmoidalis-0.91 mm) was lower than Group B (cribriform plate-0.86 mm, lateral lamella-0.84 mm, Fovea ethmoidalis-0.97 mm) which was statistically significant (p value-< 0.05).

Deep learning to predict risk of lateral skull base cerebrospinal fluid leak or encephalocele.

PURPOSE: Skull base features, including increased foramen ovale (FO) cross-sectional area, are associated with lateral skull base spontaneous cerebrospinal fluid (sCSF) leak and encephalocele. Manual measurement requires skill in interpreting imaging studies and is time consuming. The goal of this study was to develop a fully automated deep learning method for FO segmentation and to determine the predictive value in identifying patients with sCSF leak or encephalocele. METHODS: A retrospective cohort study at a tertiary care academic hospital of 34 adults with lateral skull base sCSF leak or encephalocele were compared with 815 control patients from 2013-2021. A convolutional neural network (CNN) was constructed for image segmentation of axial computed tomography (CT) studies. Predicted FO segmentations were compared to manual segmentations, and receiver operating characteristic (ROC) curves were constructed. RESULTS: 295 CTs were used for training and validation of the CNN. A separate dataset of 554 control CTs was matched 5:1 on age and sex with the sCSF leak/encephalocele group. The mean Dice score was 0.81. The sCSF leak/encephalocele group had greater mean (SD) FO cross-sectional area compared to the control group, 29.0 (7.7) mm2 versus 24.3 (7.6) mm2 (P = .002, 95% confidence interval 0.02-0.08). The area under the ROC curve was 0.69. CONCLUSION: CNNs can be used to segment the cross-sectional area of the FO accurately and efficiently. Used together with other predictors, this method could be used as part of a clinical tool to predict the risk of sCSF leak or encephalocele.

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.

Individual SNOT-22 Items Aid in Differentiating Between Spontaneous Cerebrospinal Fluid Rhinorrhea and Chronic Rhinosinusitis Without Nasal Polyps.

OBJECTIVES: Spontaneous cerebrospinal fluid (CSF) rhinorrhea is a diagnostic challenge due to its overlapping symptomatology with other sinonasal diseases. The objective of this study was to investigate whether items on the sinonasal outcome test (SNOT)-22 could suggest a diagnosis of spontaneous CSF rhinorrhea versus chronic rhinosinusitis without nasal polyps (CRSsNP). METHODS: A multi-institutional retrospective chart review of patients with spontaneous CSF rhinorrhea and a control group of CRSsNP patients was performed. Individual SNOT-22 scores and domain scores were compared. RESULTS: One hundred fifteen patients were included in both cohorts. Of the patients in the CSF rhinorrhea group, 48% were misdiagnosed as chronic rhinosinusitis (CRS) prior to the correct identification of a CSF leak. On bivariate analysis, the CSF rhinorrhea group scored significantly higher on the SNOT-22 for runny nose (P < .001) and was more likely to designate this symptom as most important (P < .001). The CRSsNP group scored significantly higher in nasal blockage (P < .001), thick nasal discharge (P < .001), facial pain/pressure (P < .001), and in the ear/facial (P < .001) and rhinologic (P = .003) domains. Multivariable logistic regression revealed that runny nose (P < .001) was most predictive of spontaneous CSF rhinorrhea while nasal blockage (P < .001), thick nasal discharge (P < .001), and facial pain/pressure (P = .001) were predictive of CRSsNP after adjusting for relevant confounders. No significant difference was observed in total SNOT-22 scores between groups (P = .676). CONCLUSIONS: Spontaneous CSF rhinorrhea is commonly misdiagnosed as other sinonasal pathologies. However, individual SNOT-22 items can help aid in suggesting a CSF leak. Spontaneous CSF rhinorrhea should be suspected in patients who have high SNOT-22 scores for runny nose and report this symptom as most important, but have lower scores related to the other cardinal symptoms of CRS.

Optic nerve sheath diameter correlates to intracranial pressure in spontaneous CSF leak patients.

BACKGROUND: Spontaneous cerebrospinal fluid (sCSF) leaks develop from pressure erosion due to idiopathic intracranial hypertension, treatment of which is paramount to preventing recurrence. Direct measurements of intracranial pressure (ICP) for monitoring response to treatment via lumbar drain (LD) or ventriculostomy are invasive and have risks. The objectives of this study are to determine whether ultrasonographic measurements of optic nerve sheath diameter (ONSD) correlate with LD ICP in patients with sCSF leaks undergoing treatment, and whether ONSDs are larger in patients with sCSF leaks than controls. METHODS: Subjects with sCSF leaks and controls were prospectively recruited. ONSD, sex, and body mass index (BMI) were analyzed. For sCSF leak subjects, ultrasonography was performed at the time of LD opening and each pressure check postoperatively, including the acetazolamide response. In control patients, measurements were obtained at the time of surgery. Pearson's correlation between ONSD and ICP was performed. RESULTS: Subjects with sCSF leaks (n = 9, age 52.4 ± 9.5, all female) and controls (n = 8, age 60.1 ± 14.8, two females) had significantly different BMIs, 38.4 ± 8.1 vs. 29.2 ± 4.8, t(15) = 2.793, p = 0.014. ONSD was strongly correlated with ICP measurements (r = 0.583, p = 0.002). However, percentage change in ONSD and ICP measurements were more strongly correlated (r = 0.733, p < 0.001). Patients with sCSF leaks had significantly higher ONSDs than controls, 0.63 cm ± 0.044 vs. 0.56 cm ± 0.074, t(15) = 2.329, p = 0.034. CONCLUSION: ONSD significantly correlated with ICP in sCSF leak patients and was wider in sCSF leak subjects than controls. Ultrasonography has utility in monitoring the ICP response to acetazolamide.

Endonasal endoscopic management of spontaneous cerebrospinal fluid rhinorrhoea: The Birmingham UK experience.

BACKGROUND: Spontaneous cerebrospinal fluid (CSF) leaks (SCSFL) occur in the absence of trauma, surgery, or underlying intracranial pathology. They represent a significant healthcare burden on patients with complications such as meningitis. We present our experience of SCSFL repair via the endonasal endoscopic approach. METHODS: All patients who underwent CSF fistula repair at a tertiary UK hospital, between 1st January 2012 to 31st December 2019, were identified and had their case notes analyzed retrospectively. RESULTS: There were 33 patients included consisting of 27 (81.8%) females, with age range from 31 to 81 years (mean 55.2). Mean body mass index (BMI) was 35.2 kg/m2 , with 32 (97.0%) patients overweight (BMI >25). All patients presented with intermittent watery rhinorrhoea and had a positive biochemical analysis. Computed tomography (CT) and/or magnetic resonance imaging (MRI) identified leak sites in 29 patients (87.9%). The most common intraoperative defect site was the cribriform plate (42.4%). A variety of closing techniques were used including onlay grafts (72.7%), tissue glue (87.9%), nasoseptal flaps (63.6%), mucosal free grafts (21.2%), fat grafts (21.2%), and additional support materials (87.9%). Nasal packing was used in all patients. The average length of stay was 1.6 days. Postoperative complications occurred in two patients (6.1%) (meningitis, epistaxis). Overall, there was a successful primary repair in 32 (97.0%) patients with most cases employing a multilayered reconstruction method (78.8%). CONCLUSION: Our results demonstrate excellent success rates with the endoscopic endonasal approach to SCSFL. This adds to the literature by demonstrating a detailed analysis of the experience in SCSFL management in one of the largest UK centres.

Spontaneous Cerebro-Spinal Fluid Rhinorrhoea Caused by Sustained Intracranial Hypertension.

Cerebrospinal Fluid (CSF) leakage results from a defect in the skull base, which communicates the subarachnoid space with the nasal cavity. The most common cause of CSF leakage is traumatic, and non-traumatic causes are less common. This case report illustrates a case of a woman who presented to the emergency department with clear fluid pouring from her nose for three weeks with a fever. The patient had pneumococcal meningitis and Idiopathic Intracranial Hypertension (ICH) seven years ago. Computed Tomography (CT) sinuses showed the defect seen on the right side of the cribriform plate, and the Magnetic Resonant Imaging (MRI) confirmed the CSF leakage. The CSF leakage was diagnosed by positive B transferrin.  This case highlights a rare condition that needs early detection and treatment to prevent complications such as ascending meningitis.

The critical importance of a vascularized flap in preventing recurrence after endoscopic repair of spontaneous cerebrospinal fluid leaks and meningoencephaloceles.

OBJECTIVE: Spontaneous CSF leaks into the anterior skull base nasal sinuses are often associated with meningoencephaloceles and occur in patients with idiopathic intracranial hypertension (IIH). Endonasal endoscopic repair has become the primary method of choice for repair. The authors sought to evaluate the success rate of endoscopic closure and to identify predictive factors for CSF leak recurrence. METHODS: A consecutive series of endonasally repaired anterior skull base meningoencephaloceles was drawn from a prospectively acquired database. Lumbar punctures were not performed as part of a treatment algorithm. All patients had at least 5 months of follow-up. Chart review and phone calls were used to determine the timing and predictors of recurrence. Demographic information and details of operative technique were correlated with recurrence. Two independent radiologists reviewed all preoperative imaging to identify radiographic markers of IIH, as well as the location and size of the meningoencephalocele. RESULTS: From a total of 54 patients there were 5 with recurrences (9.3%), but of the 39 patients in whom a vascularized nasoseptal (n = 31) or turbinate (n = 8) flap was used there were no recurrences (p = 0.0009). The mean time to recurrence was 24.8 months (range 9-38 months). There was a trend to higher BMI in patients whose leak recurred (mean [± SD] 36.6 ± 8.6) compared with those whose leak did not recur (31.8 ± 7.4; p = 0.182). Although the lateral recess of the sphenoid sinus was the most common site of meningoencephalocele, the fovea ethmoidalis was the most common site in recurrent cases (80%; p = 0.013). However, a vascularized flap was used in significantly more patients with sphenoid (78.3%) defects than in patients with fovea ethmoidalis (28.6%) defects (Fisher's exact test, p = 0.005). Radiographic signs of IIH were equally present in all patients whose leak recurred (75%) compared with patients whose leak did not recur (63.3%); however, an enlarged Meckel cave was present in 100% (2/2) of patients whose leaks recurred compared with 13.3% (4/30) of patients whose leaks did not recur (p = 0.03). The average meningoencephalocele diameter tended to be larger (1.73 ± 1.3 cm) in patients with recurrence compared to those without recurrence (1.2 ± 0.66 cm; p = 0.22). A ventriculoperitoneal shunt was already in place in 3 patients, placed perioperatively in 5, and placed at recurrence in 2, none of whose leaks recurred. CONCLUSIONS: Recurrence after endonasal repair of spontaneous CSF leaks from meningoencephaloceles can be dramatically reduced with the use of a vascularized flap. Although failures of endonasal repair tend to occur in patients who have higher BMI, larger brain herniations, and no CSF diversion, the lack of vascularized flap was the single most important risk factor predictive of failure.

Primary Spontaneous Inferior Clival Cerebrospinal Fluid Leak.

Primary, spontaneous cerebrospinal fluid (CSF) leaks secondary to defects in the clivus are exceedingly rare. Additionally, primary, spontaneous CSF leaks are typically present in obese women with idiopathic intracranial hypertension (IIH). In the present study, we report the first case of a primary, spontaneous CSF leak in the inferior-posterior wall of the clivus in an atypical patient with a BMI of 18.9 kg/m2 without IIH. Accurate diagnoses of CSF leaks are imperative in the context of preventing meningitis, and delays in diagnosis and treatment are associated with worse outcomes. Improved characterization of rare, spontaneous CSF leaks may prove beneficial in correctly diagnosing affected patients.

The Endonasal Endoscopic Management of Cerebrospinal Fluid Rhinorrhea.

Introduction Cerebrospinal fluid (CSF) rhinorrhea is the result of a bony defect at the skull base with disruption of the arachnoid, dura mater, and sinonasal mucosa that leads to an active CSF leak and flow of clear fluid from the nose. The endoscopic repair of CSF leaks and skull defects have been used by an increasing number of surgeons and is the standard of care for repairing CSF leaks. Materials and methods We conducted a retrospective study of all cases of CSF leaks managed via the endonasal endoscopic approach from 2010 to 2020 at a tertiary referral hospital of King Fahad Specialist Hospital, Dammam (KFSH-D). Results Over 10 years, 61 procedures were performed on a total of 56 patients (average age, 39.9 years) with 26 spontaneous CSF leaks and 30 traumatic CSF leaks. The leak sites were frontal bone in 14% of the cases, the roof of the ethmoid in 25%, the cribriform plate of ethmoid in 39%, and the walls of sphenoid sinus in 21%; multiple site defects were found in eight patients. The defect was localized by high-resolution computed tomography (CT) of the paranasal sinuses and skull base and magnetic resonance imaging (MRI) in all patients. CT cisternography, intrathecal fluorescein injection, and topical application of fluorescein dye were used in patients as required. A combination of free grafts and flaps materials were used in most patients. A middle and inferior turbinate graft was used in 12 patients, a septal cartilage graft in 18 patients, and a pedicled nasoseptal flap in 12 patients. The success rate was 92% after the first closure attempt. A recurrence of CSF leaks was observed in four patients. The mean hospitalization time was 6.5 days. The postoperative follow-up period ranged from one year to 10 years with a mean postoperative follow-up time of three years. Conclusions The endonasal endoscopic approach is the current standard of care for repairing most CSF leaks and skull base defects. We have had an excellent experience with endonasal endoscopic CSF leak repair, with high success rates and low morbidity. Our results support the effectiveness and safety of this technique and should encourage otolaryngologists to apply the procedure in cases of CSF leak.

International Consensus Statement: Spontaneous Cerebrospinal Fluid Rhinorrhea.

BACKGROUND: The association between spontaneous cerebrospinal fluid (CSF) leak/rhinorrhea and idiopathic intracranial hypertension (IIH) has been increasingly recognized over the last years. However, considerable variability of opinion regarding the assessment, investigations, and management of patients with spontaneous CSF rhinorrhea remains. METHODS: A consensus group was formed from experts from Europe, Asia, Australia, South and North America. Following literature review and open discussions with members of the panel, a set of 61 statements was produced. A modified Delphi method was used to refine expert opinion with 3 rounds of questionnaires and a consensus group meeting in Santo-Rhino meeting in September 2019. RESULTS: Fifty statements (82% of total) on spontaneous CSF leak and IIH reached consensus. In 38 of 50 statements, the median response was 7 (strongly agree) and in the 12 remaining statements the median response was 6 (agree). Eleven statements were excluded because they did not reach consensus and one new statement was added during SantoRhino meeting. The final statements refer to patient history and clinical examination ("History taking should include presence of headache, tinnitus and visual defects"), investigations (role of Thin Slice Computed Tomography and CISS/FLAIR sequences in Magnetic Resonance Imaging), principles of management (watchful waiting or measures to reduce ICP are supplementary but cannot subsitute surgical closure), surgical technique, intraoperative, early postoperative and long term management. CONCLUSION: We present fifty consensus statements on the diagnosis, investigation, and management of spontaneous CSF rhinorrhea based on the currently available evidence and expert opinion. Although by no means comprehensive and final, we believe they can contribute to the standardization of clinical practice. Early diagnosis, prompt surgical closure of the defect, assesment for and treatment of potentially co-existing idiopathic intracranial hypertension in a comprehensive multidisciplinary approach are essential in order to successfully manage spontaneous CSF rhinorrhea, reduce associated morbidity and prevent recurrence.

An Expedited Intracranial Pressure Monitoring Protocol Following Spontaneous CSF Leak Repair.

OBJECTIVE: Spontaneous cerebrospinal fluid (CSF) leaks represent a unique subset of skull base pathology and require distinctive management. Perioperative evaluation and management of intracranial hypertension are essential in preventing further erosion of the skull base and development of recurrent leak. The objective of this study is to evaluate the safety and utility of an expedited protocol for recording and managing intracranial hypertension following endoscopic repair of spontaneous CSF leaks. METHODS: Prospectively collected data was reviewed in patients undergoing endoscopic repair of spontaneous CSF leaks between January 2017 and March 2020. A standard intracranial pressure monitoring protocol was compared to an expedited protocol (EP), and data regarding the two groups was compared for leak location, short-term success of skull base repair, complications, hospital length of stay, and cost-based analysis. RESULTS: Fifty-five patients (standard protocol, n = 28 vs. EP, n = 27) were included in the study. Leak location was similar between cohorts, with the lateral recess being the most common locations in both groups (37.9% vs. 40.6%; P = .90). Postoperative complications (3.6% vs. 7.4%; P = .53) and ventriculoperitoneal shunt rate (32.1% vs. 22.2%; P = .41) were similar among cohorts. There was no difference in lumbar drain complications (0% vs. 7.4%; P = .14) or recurrent leak (7.1% vs. 0%; P = .16). Length of stay was shorter in the EP group [median(interquartile range): 3(1) vs. 2 (1); P < .01]. Total hospital charges were similar between groups (median (USD/$1,000): 83.57 ± 49.58 vs. 83.93 ± 46.11; P = .18). CONCLUSION: An expedited monitoring protocol shortened hospital stay without increased risk of complications. LEVEL OF EVIDENCE: III Laryngoscope, 131:E408-E412, 2021.

Correlation of spontaneous and traumatic anterior skull base CSF leak flow rates with fluid pattern on early, delayed, and subtraction volumetric extended echo train T2-weighted MRI.

OBJECTIVE: CSF leakage is a potentially fatal condition that may result when a skull base dural defect permits CSF communication between the cranial vault and sinonasal cavities. Flow rate is an important property of CSF leaks that can contribute to surgical decision-making and predispose patients to complications and inferior outcomes. Noninvasive preoperative prediction of the leak rate is challenging with traditional diagnostic tools. The present study compares fluid configurations on early and late volumetric extended echo train T2-weighted MRI by using image tracings and sequence subtraction as a novel method of quantifying CSF flow rate, and it correlates radiological results with intraoperative findings and clinical outcomes. METHODS: A total of 45 patients met inclusion criteria for this study and underwent 3-T MRI. Imaging sequences included two identical CUBE T2 (vendor trade name for volumetric extended echo train T2) acquisitions at the beginning and end of the scanning session, approximately 45 minutes apart. Twenty-five patients were confirmed to have definitive spontaneous or traumatic anterior skull base CSF leaks. Semiautomated volumetric segmentation of CSF intensity was performed on both CUBE data sets by using 3D-Slicer software, and volumes were subtracted to obtain accumulated CSF volume. These imaging-derived fluid accumulations were correlated with high- or low-flow states, as well as ultimate treatment outcomes including recurrences. RESULTS: Of the 45 patients, 25 (55.6%) had definitive evidence of CSF leakage, and 22 (88%) of these underwent surgical repair. Patients with high-flow CSF leaks had higher early (4.058 cm3 vs 0.982 cm3, p = 0.04), late (4.58 cm3 vs 1.096 cm3, p = 0.04), and accumulated (0.53 cm3 vs 0.11 cm3, p = 0.01) fluid volume measurements than patients with low-flow leaks. The 5 (22.7%) patients who exhibited postoperative CSF leak recurrence had significantly greater early (6.30 cm3 vs 1.23 cm3, p = 0.008) and late (6.87 cm3 vs 1.45 cm3, p = 0.008) volumes. Accumulated volume was not significantly greater in patients with leak recurrence (0.58 cm3 vs 0.22 cm3, p = 0.07). Early, late, and accumulated volumes were significantly correlated with postoperative hospital stay as well as duration of postoperative lumbar drain placement (p < 0.05 for all measures). CONCLUSIONS: High-resolution CUBE T2 MRI, coupled with precise volumetric segmentation and subtraction of sinonasal hyperintensity, not only demonstrated predictive value in differentiating low- and high-flow CSF leaks, but also correlated with postoperative complications such as leak recurrence. These findings may be useful in the clinical workup and neurosurgical management of patients with skull base CSF leaks.

Dural venous sinus stenting as a stand-alone treatment for spontaneous skull base CSF leak secondary to venous pseudotumor cerebri syndrome.

Most spontaneous CSF leaks (SCSFL) are associated with an underlying pseudotumor cerebri syndrome (PTCS). Treatment generally includes surgical leak repair and PTCS correction, as untreated PTCS carries a risk of recurrence. We describe a 72-year-old woman with rhinorrhea, aural fullness, and posterior nasal drip. CT and MRI showed signs of CSF hypovolemia and PTCS, as well as bilateral transverse sinus stenoses. CT and MRI cisternography documented CSF leaks through the right cribriform plate and the posterior aspect of the petrous bone. Opening CSF pressure was 6 cm H2O. Dural venous sinus stenting (DVSS) was performed after failed conservative treatment. Rhinorrhea resolved 3 days after stenting, aural fullness 1 month later. After 6 months, signs of CSF hypovolemia had disappeared on MRI and the stents were patent. After 9 months, the patient had a transient, spontaneously resolving episode of rhinorrhea. She has been symptom-free for the remaining 39 months of follow-up.

Skull Base Dural Thickness and Relationship to Demographic Features: A Postmortem Study and Literature Review.

Dural membrane is an important anatomic structure that surrounds and protects the entire central nervous system. Physical properties of the dura have many pathophysiological and therapeutic implications in cranial surgery, especially skull base disorders. The aim of this study is to investigate variation in skull base dural thickness and correlation with different demographic parameters. At the time of autopsy, the petrous apex dura with the underlying bone of 20 cadavers was harvested. Dural thickness was independently measured by two pathologists at the thinnest and thickest segments in the specimen. Correlational analyses were then performed to compare dural thickness with gender, age, neck circumference, height, weight, and body mass index (BMI). Mean, minimum, and maximum skull base dural thickness in our study was 0.36, 0.27, and 0.46 mm, respectively. Age demonstrated a negative correlation with dural thickness with significantly thinner dura in the older subjects, p = 0.01. There was a trend toward thinner dura in females that approached statistical significance, p = 0.06. No strong correlation could be found with body weight, height, neck circumference, or BMI. Our findings show a considerable intersubject and intrasubject variability in skull base dural thickness. Some demographic parameters also seem to impact dural thickness. Additional histological studies are needed for better understanding of the pathophysiological mechanisms pertaining to the tensile properties of the dural membrane.

Outcomes of outpatient endoscopic repair of cerebrospinal fluid rhinorrhea.

BACKGROUND: Endoscopic repair of anterior skull-base defects has become the gold standard for management of cerebrospinal fluid (CSF) rhinorrhea. Both improved techniques and adjuvant therapies have led to accepted success rates of greater than 90%. As management has evolved, shorter hospitalizations have been required and the goal of this study is to analyze the outcomes of patients repaired on an outpatient basis vs those managed as inpatients postoperatively. METHODS: Patients undergoing endoscopic repair of CSF rhinorrhea between 2004 and 2014 were identified by review of medical records. Demographic and clinical data were collected and compared between patients having surgery with and without postoperative admission. Patients managed with lumbar drains were not included. Statistical analyses were preformed to determine if any differences in patient demographics and outcomes existed. RESULTS: A total of 86 patients were identified; 39 of 86 patients (45.3%) underwent outpatient surgery; 47 patients were admitted postoperatively with a mean hospital stay of 1.66 days with a median and mode of 1 day. No statistically significant differences were found between leak location, etiology, rates of recurrence, or complications. The outpatient group was found to have a greater proportion of small defects <1 cm2 (p = 0.003). Repair technique was also significantly different between groups (p = 0.001). CONCLUSION: Endoscopic management of CSF rhinorrhea is a safe method of treatment with reliable success rates. Our retrospective analysis revealed comparable outcomes in patients treated with and without postoperative hospital admission, and supports the idea that outpatient management may be reasonable in certain patients, especially those with defects <1 cm2 .

The endoscopic endonasal approach to repair of iatrogenic and noniatrogenic cerebrospinal fluid leaks and encephaloceles of the anterior cranial fossa.

OBJECTIVE: The current approach for the diagnosis and repair of spontaneous and traumatic anterior skull-base defects is oulined, highlighting the controversies that exist in the field and describing the strategies required to access different segments of the anterior cranial fossa. METHODS: We reviewed the literature concerning endoscopic management of anterior skull-base defects. These publications have been combined with our own experience repairing cerebrospinal fluid (CSF) leaks and encephaloceles that developed spontaneously, traumatically, or intentionally as a result of endoscopic skull-base surgery. RESULTS: We present a systematic methodology for the repair of these defects. We have divided our surgical approach into four separate corridors. These are the transnasal, transsphenoidal, transethmoidal, and transmaxillary corridors. Dissection strategies vary for each corridor, but with a combination of approaches, all areas of the anterior skull base can be accessed. Skull-base defects are successfully repaired with a multilayered closure that often involves use of a vascularized pedicled mucosal flap. Adoption of this technique has decreased our rate of postoperative CSF leak from 5.9%-3.1%. CONCLUSIONS: Endoscopic endonasal repair of CSF leaks and encephaloceles has evolved significantly during the past decade. The versatility of different endoscopic approaches through the four endonasal corridors allows for the endoscopic repair of almost all skull-base defects. The use of vascularized pedicled mucosal flaps has evolved to cover these defects as part of multilayered closure strategies.

Increased intracranial pressure in spontaneous CSF leak patients is not associated with papilledema.

OBJECTIVE: Spontaneous cerebrospinal fluid (CSF) leaks typically present in patients with undiagnosed idiopathic intracranial hypertension (IIH) secondary to pressure erosion of the skull base. Despite elevated intracranial pressure (ICP) on lumbar puncture or ventriculostomy, patients with spontaneous CSF leaks rarely complain of visual disturbances. The objective of this study is to correlate the presence of preoperative papilledema with opening ICP in patients undergoing endoscopic repair of spontaneous CSF leaks. STUDY DESIGN: Prospective study. SETTING: Tertiary hospital. METHODS: Prospective evaluation of patients with spontaneous CSF leaks was performed over a 1-year period (December 2012 to December 2013). Fundoscopic examination for papilledema was completed preoperatively and CSF pressure measured by lumbar puncture or ventriculostomy intraoperatively. Data regarding demographics, nature of presentation, and body mass index (BMI) were also recorded and compared to a control cohort of IIH patients with papilledema. RESULTS: Sixteen patients (average age 52) were evaluated. Obesity was present in 94% of individuals (average BMI = 43, range, 27-65). Papilledema was absent preoperatively in all subjects. Opening pressures via lumbar puncture/ventriculostomy were 27.4 ± 7.7 cmH20. Following 6 hours of clamping, measurements significantly increased to 36 ± 9.6 cmH20 (P < .001). IIH controls (average age 33, average BMI = 36, range, 21-52) exhibited average ICP (36.2 ± 11.7) identical to postclamp measurements in the spontaneous CSF leak cohort. CONCLUSIONS: Subjects with spontaneous CSF leaks had postclamping average ICP identical to controls with IIH and papilledema. Such evidence suggests that a CSF leak in this patient population provides sufficient pressure diversion to avoid the development of papilledema.

Spontaneous CSF leaks: low CSF volume syndromes.

Practically all cases of spontaneous intracranial hypotension results from spontaneous cerebral spinal fluid (CSF) leaks, often at the level of the spine and only rarely from the skull base. The triad of orthostatic headaches, diffuse pachymeningeal enhancement on head imaging and low CSF opening pressure is considered the hallmark of these leaks but substantial variability is noted in most aspects of this disorder including in features of the headaches, imaging and CSF findings, response to treatment and outcome.

Distant pseudomeningoceles of the ventral skull base: a report of 2 cases.

BACKGROUND: The objective of this case series was to report what is to the best of our knowledge the first reports of nasopharyngeal and soft palate pseudomeningoceles tracking submucosally from the sphenoid sinus. METHODS: Analysis of cases through medical records. RESULTS: Two cases of middle-aged male patients presented to our tertiary care university teaching hospital for recurrent meningitis and a history of cerebrospinal fluid (CSF) rhinorrhea. Both were found to have pseudomeningoceles distant from the sphenoid sinus. One was tracking to the mucosa of the Eustachian tube, and the other to the dorsum of the soft palate. Both were found to be tracking submucosally from the sphenoid sinus, to the vidian canal, to the lateral nasopharyngeal wall, to their respective locations at the Eustachian tube and dorsum of the soft palate. CSF closure was performed with a transnasal endoscopic repair using the pedicled nasoseptal flap for 1 patient and Alloderm for the other, both with successful cessation of CSF rhinorrhea. CONCLUSION: We present these cases of distant spontaneous CSF leaks. We review the literature and discuss case management.