Radiographic signs of elevated intracranial pressure in idiopathic cerebrospinal fluid leaks: a possible presentation of idiopathic intracranial hypertension

Evaluation of anterior and middle cranial fossa intraosseous arachnoid granulations with 3D T2-SPACE sequence

OBJECTIVES

Arachnoid granulations (AG) can be located anywhere outside the dural sinuses. Their presence is thought to be associated with idiopathic intracranial hypertension (IIH) and cerebrospinal fluid (CSF) leaks. It was aimed to evaluate the intraosseous AGs located in the middle and anterior cranial fosses in detail with three-dimensional T2-SPACE (Sampling Perfection with Application optimized Contrasts using different flip angle Evolution-Siemens) imaging and to investigate their clinical significance.

MATERIALS AND METHODS

Sixty-five intraosseous AG of 46 patients were included in this retrospective study. The highest diameter, bone indentation degree (in the inner tabula, diploe distance, reaching and exceeding the outer tabula), content (CSF/+parenchyma) of each AG were evaluated by 2 experienced radiologists. In addition, the presence of other MRI findings supporting IIH was examined.

RESULTS

Additional signs of IIH were detected in 25 patients, and they were statistically significantly more common in the middle cranial fossa. Parenchymal herniation (in four patients) was more common in the young population.

CONCLUSIONS

Intraosseous AGs can be evaluated in detail with T2-SPACE imaging. Determining intraosseous AG is very important both as an indicator of IIH and in terms of its content. T2-SPACE imaging is superior to CT and conventional sequences in this regard.

Management of recurrent cerebrospinal fluid leak, current practices and open challenges. A systematic literature review

Cerebrospinal fluid leak (CSFL) is a rare pathological condition which requires prompt and adequate management due to the high rate of associated major complications. At present, CSFL can be successfully treated through endoscopic endonasal approaches with success rates higher than 90%. Despite this, CSFL recurrence may occur, and its management is critical and still represents a matter of debate. A systematic review of the literature on the management of recurrent CSFL was conducted. It included a cohort of 1,083 cases of CSFL treated with surgical or conservative approaches; 112 cases of recurrence were reported for an overall recurrence rate of 10.3%. Most of the leaks were localised in the anterior skull base (68.3%) and identification of recurrent CSFL may be troublesome. Therefore, the entire skull base must be meticulously examined and long-term follow-up is mandatory. The risk for CSFL recurrence is higher in patients affected by idiopathic intracranial hypertension (IIH), but its role in CSFL recurrence is yet to be understood. Recurrent CSFL must be repaired as soon as possible in order to reduce the risk of intracranial complications. The use of early post-operative CSF diversion by lumbar drain (LD) is currently a matter of debate even in case of CSFL recurrences.

Symptoms Underestimate the Presence of Obstructive Sleep Apnea in Patients with Spontaneous Cerebrospinal Fluid Leaks of the Temporal Bone

OBJECTIVE

To determine the severity of symptoms and degree of obstructive sleep apnea (OSA) in patients with spontaneous cerebrospinal fluid (sCSF) leaks of the temporal bone given the known association between sCSF leaks and OSA.

STUDY DESIGN

Retrospective case review.

SETTING

Ambulatory clinics in tertiary referral centers.

PATIENTS

Polysomnogram testing in 34 consecutive patients who had been diagnosed with sCSF leaks of the temporal bone was examined. Diagnosis of sCSF leak was defined as biochemically confirmed CSF from middle ear fluid with no other obvious source.

INTERVENTION

Diagnostic.

MAIN OUTCOMES MEASURES

Patient characteristics (age, sex, body mass index, Epworth Sleepiness Scale score, presence of hypoxia, overnight change in blood pressure, and apnea hypopnea index [AHI]) were recorded. Diagnosis of OSA was defined as mild when AHI ≥5 and <15/h, moderate when AHI ≥15 and <30/h, and severe when AHI ≥30/h.

RESULTS

Of the 34 patients, 28 (82%) had a confirmed diagnosis of OSA. There was a male predisposition in those with OSA, and 17 of 28 (61%) were male. A majority were overweight, and the mean body mass index was 30.1 (SD, 4.8; range, 23.2-40) kg/m2. The mean severity of OSA was moderate, and the mean AHI was 28.7 (SD, 21.9; range, 5.4-92.8). Of the 28 patients, 13 with OSA (46%) had Epworth Sleepiness Scale scores higher than 8, suggesting that many were asymptomatic for excessive daytime sleepiness at the time of presentation.

CONCLUSION

OSA is highly prevalent among patients with sCSF leaks of the temporal bone. Patients with sCSF leaks irrespective of symptoms of OSA should undergo formal polysomnogram testing.

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.

Seizure as the presenting sign of idiopathic intracranial hypertension

A 38-year-old man presented to the emergency room with a new generalised tonic-clonic seizure. He also complained of headaches, and brain MRI/magnetic resonance venography (MRV) showed an anterior left temporal encephalocoele with gliosis and brain parenchyma herniating into the left foramen ovale. Ophthalmic examination revealed bilateral optic disc oedema and his lumbar puncture confirmed an elevated opening pressure of 48 cm of water. He was diagnosed with idiopathic intracranial hypertension (IIH) and his papilloedema resolved with weight loss and acetazolamide. Raised intracranial pressure (ICP) can be associated with encephalocoeles and lead to seizures. It is important to screen for papilloedema in these patients as they are at risk for permanent vision loss. This was a unique case in which IIH was diagnosed only after a seizure due to an encephalocoele, which was likely related to chronically undetected raised ICP.

Prediction of Postoperative Risk of Raised Intracranial Pressure After Spontaneous Skull Base Cerebrospinal Fluid Leak Repair

BACKGROUND

A relationship between idiopathic intracranial hypertension and spontaneous skull base cerebrospinal fluid (CSF) leaks has been proposed, by which CSF leak decreases intracranial pressure (ICP) and masks the symptoms and signs of elevated ICP. These patients are at risk of developing papilledema, symptoms of elevated ICP, or a recurrent CSF leak after CSF leak repair. The objective of this study was to assess whether radiographic signs of raised ICP on preoperative magnetic resonance or computed venography (MRI or CTV) are predictors of postoperative papilledema, recurrence of CSF leak, or need for CSF shunt surgery.

METHODS

We performed a retrospective review of systematically collected demographics, fundus examination, and presurgical brain MRI and magnetic resonance venography/computed tomography venography (MRV/CTV) in patients seen at 1 institution between 2013 and 2019 with spontaneous skull base CSF leak repair. Patients were divided into 2 groups depending on whether they developed papilledema, recurrent CSF leak, or required CSF shunting (Group 1) or not (Group 2).

RESULTS

Fifty-seven patients were included, among whom 19 were in Group 1. There was no difference in demographic characteristics or clinical features between patients in Group 1 and Group 2. Controlling for other imaging features, bilateral transverse venous sinus stenosis (TVSS) on preoperative imaging increased the odds of being in Group 1 by 4.2 times (95% confidence interval [CI], 1.04-21.2, P = 0.04), optic nerve tortuosity decreased the odds of being in Group 1 by 8.3 times (95% CI: 1.4-74.6, P = 0.02).

CONCLUSION

Imaging of the intracranial venous system with MRV or CTV is warranted before repair of spontaneous CSF leak, as bilateral TVSS is an independent risk factor for postoperative papilledema, CSF leak recurrence, or need for a CSF shunting procedure.

MR findings suggestive of idiopathic intracranial hypertension in 117 patients with spontaneous cerebrospinal fluid rhinorrhea

PURPOSE

The purpose of this study is to document the prevalence of MR findings suggestive of idiopathic intracranial hypertension (IIH) in patients undergoing endoscopic repair of spontaneous CSF rhinorrhea (SCSFR).

METHODS

In a retrospective study, MR images of 117 consecutive patients who had undergone endoscopic repair of SCSFR were evaluated for features suggestive of IIH (empty sella, widened optic nerve sheath, tortuous optic nerve, flattened posterior globe, and enlarged Meckel's cave). Pituitary height was used to diagnose partial and complete empty sella. MR images were independently evaluated by two of the authors without knowledge of the clinical findings. Consensus method was used to resolve differences between the two evaluators.

RESULTS

Empty or partially empty sella was diagnosed in the MR of 105 (89.7%) patients. In 38/105 (36.2%) patients with empty/partial empty sella, no additional MR findings were present. In 43/105 (41%) patients, one or more of the MR features with high specificity for diagnosis of IIH (flattened posterior globe and enlarged Meckel's cave) were seen. In the other 24 (22.9%) additional MR findings, less specific for IIH (widened optic nerve sheath, tortuous optic nerve) were noted. Papilledema was seen in 11 of 60 (18.3%) patients who underwent funduscopic examination. All patients with papilledema had empty/partial empty sella, and 9/11 (81.8%) had an additional MR finding suggestive of IIH.

CONCLUSION

The majority of patients with SCSFR have MR imaging features of IIH. These imaging features should be a major component of previously published modified diagnostic criteria for IIH in patients with SCSFR.

Imaging Characteristics of Sigmoid Sinus Wall Anomalies, Idiopathic Intracranial Hypertension, and Spontaneous CSF Leaks

OBJECTIVE

To assess the frequency of radiographic features of elevated intracranial pressure (ICP) in patients with sigmoid sinus wall anomalies (SSWA) and compare to those in idiopathic intracranial hypertension (IIH) and spontaneous CSF (sCSF) leaks.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary care center.

PATIENTS

110 patients - 62 SSWAs, 19 IIH, 29 sCSF leaks.

MAIN OUTCOME MEASURES

Demographics, comorbidities and radiographic features by diagnosis.

RESULTS

Imaging findings indicative of elevated ICP were similar across all three groups, as were body mass index, hyperlipidemia and diabetes. On univariate analysis, sCSF leak patients were significantly older than SSWA (60 vs. 41 years, p < 0.001) and IIH (60 vs. 40 years, p < 0.001) patients. They had a greater prevalence of arachnoid granulations than SSWA (75.8% vs. 37.1%, p < 0.01) and tegmen dehiscence than both SSWA and IIH (93.1% vs. 75.8% vs. 57.8%, p = 0.01), though a lower prevalence of empty sella than SSWA (44.8% vs. 72.5%, p < 0.001). SSWAs were present in roughly 44.3% of IIH and sCSF leak patients, and IIH in roughly 15.8% of SSWA and sCSF leak patients. Age (OR = 1.1, p = 0.001), hypertension (OR = 8.3, p = 0.01) and empty sella (OR = 0.1, p = 0.01) were predictive of sCSF leaks compared to SSWAs on multivariate analysis.

CONCLUSIONS

Many radiographic and clinical features of elevated ICP are found at similar rates among patients with SSWA, IIH and sCSF leaks, suggesting a common underlying process. SSWAs seem to present earlier along this spectrum of phenotypes, while sCSF leaks present later. Differences in age, metabolic syndrome and ICP may influence a patient's clinical presentation.

Special MRI Techniques to Suss out Spontaneous Cerebrospinal Fluid Leaks

Anterior skull base cerebrospinal fluid (CSF) fistulas result from skull base osteodural defects, allowing subarachnoid space CSF to escape into pneumatized cavities such as the paranasal sinuses and nasal fossa. Precise localization, characterization, and effective treatment of CSF leaks is essential to prevent meningitis, treatment failure, or recurrence. Advances in magnetic resonance imaging have improved radiologists' ability to localize and characterize anterior skull base CSF fistulas. This article reviews new imaging techniques enabling diagnostic location of CSF fistulas, with an emphasis on magnetic resonance imaging-based techniques.

A Unique Subset: Idiopathic Intracranial Hypertension Presenting as Spontaneous CSF Leak of the Anterior Skull Base

Introduction Spontaneous cerebrospinal fluid (CSF) leaks represent a unique clinical presentation of idiopathic intracranial hypertension (IIH), lacking classical features of IIH, including severe headaches, papilledema, and markedly elevated opening pressures.

Methods Following a single-institution retrospective review of patients undergoing spontaneous CSF leak repair, we performed a literature review of spontaneous CSF leak in patients previously undiagnosed with IIH, querying PubMed.

Results Our literature review yielded 26 studies, comprising 716 patients. Average age was 51 years with 80.8% female predominance, and average body mass index was 35.5. Presenting symptoms included headaches (32.5%), visual disturbances (4.2%), and a history of meningitis (15.3%). Papilledema occurred in 14.1%. An empty sella was present in 77.7%. Slit ventricles and venous sinus stenosis comprised 7.7 and 31.8%, respectively. CSF leak most commonly originated from the sphenoid sinus (41.1%), cribriform plate (25.4%), and ethmoid skull base (20.4%). Preoperative opening pressures were normal at 22.4 cm H2O and elevated postoperatively to 30.8 cm H2O. 19.1% of patients underwent shunt placement. CSF leak recurred after repair in 10.5% of patients, 78.6% involving the initial site. A total of 85.7% of these patients were managed with repeat surgical intervention, and 23.2% underwent a shunting procedure.

Conclusion Spontaneous CSF leaks represent a distinct variant of IIH, distinguished by decreased prevalence of headaches, lack of visual deficits, and normal opening pressures. Delayed measurement of opening pressure after leak repair may be helpful to diagnose IIH. Permanent CSF diversion may be indicated in patients exhibiting significantly elevated opening pressures postoperatively, refractory symptoms of IIH, or recurrent CSF leak.

The relationship between spontaneous cerebrospinal fluid leak and idiopathic intracranial hypertension

Surgical treatment of spontaneous cerebrospinal fluid (CSF) leak is now performed by ENT surgeons, endonasal endoscopy being preferred to craniotomy as less invasive. However, it is often the symptom of underlying idiopathic intracranial hypertension, which lies outside the traditional sphere of ENT competence. Surgery is a necessary step, but should not obscure the need to treat the underlying pathology. This treatment is complex, and requires multidisciplinary team-work between otorhinolaryngologist, ophthalmologist, neurologist, neurosurgeon, radiologist, dietician, endocrinologist and psychotherapist. The present update details this multidisciplinary management to which the ENT surgeons must be attentive before and after spontaneous CSF leak repair.

Low incidence of true Sternberg's canal defects among lateral sphenoid sinus encephaloceles

BACKGROUND

Spontaneous sphenoid sinus cerebrospinal fluid (CSF) encephaloceles have been postulated to arise from a persistent Sternberg's canal. However, recent evidence has questioned this embryological etiology. We examined the anatomic location of a series of lateral sphenoid sinus encephaloceles to determine if they corresponded with the location of Sternberg's canal.

METHODS

We queried a prospectively acquired database of surgically treated spontaneous CSF leaks and identified those arising from the sphenoidal sinus. Images were reviewed to characterize the leaks with respect to the foramen rotundum (FR) and the vidian canal (VC). Four leak types were classified of which Type I (medial to FR and VC entering nasopharynx) was theoretically located in the precise location of Sternberg's canal. Type II was medial to FR; Type III was lateral to FR; Type IV passed through an enlarged FR into sphenoid sinus. Demographic data were analyzed.

RESULTS

Of 103 repaired CSF leaks, 17 arose from the lateral sphenoid sinus. There were no true Type I leaks, 3 Type II leaks, 12 Type III leaks, and 2 Type IV leaks. No differences were found with respect to sphenoid pneumatization, BMI, age, sex, arachnoid pits, or postoperative leak between different types.

CONCLUSIONS

No evidence was found to support the existence of a classic Sternberg canal CSF leak, supporting the hypothesis that most sphenoid spontaneous leaks likely occur secondary to chronically elevated ICP. Rare cases may be related to a weakness in the sphenoid wall in the region of Sternberg's canal.

Do Most Patients With a Spontaneous Cerebrospinal Fluid Leak Have Idiopathic Intracranial Hypertension?

BACKGROUND

The association between cerebrospinal fluid (CSF) leaks at the skull base and raised intracranial pressure (ICP) has been reported since the 1960s. It has been suggested that spontaneous CSF leaks might represent a variant of idiopathic intracranial hypertension (IIH). We review the evidence regarding the association between spontaneous CSF leaks and IIH, and the role of ICP in the pathophysiology of nontraumatic skull base defects. We also discuss the management of ICP in the setting of CSF leaks and IIH.

EVIDENCE ACQUISITION

References were identified by searches of PubMed from 1955 to September 2018 with the terms "idiopathic intracranial hypertension" and "cerebrospinal fluid leak." Additional references were identified using the terms "pseudotumor cerebri," "intracranial hypertension," "benign intracranial hypertension," and by hand search of relevant articles.

RESULTS

A CSF leak entails the egress of CSF from the subarachnoid spaces of the skull base into the surrounding cavitary structures. Striking overlaps exist regarding demographic, clinical, and radiological characteristics between IIH patients and those with spontaneous CSF leaks, suggesting that some (if not most) of these patients have IIH. However, determining whether a patient with spontaneous CSF leak may have IIH may be difficult, as signs and symptoms of raised ICP may be obviated by the leak. The pathophysiology is unknown but might stem from progressive erosion of the thin bone of the skull base by persistent pulsatile high CSF pressure. Currently, there is no consensus regarding the management of ICP after spontaneous CSF leak repair when IIH is suspected.

CONCLUSIONS

IIH is becoming more widely recognized as a cause of spontaneous CSF leaks, but the causal relationship remains poorly characterized. Systematic evaluation and follow-up of patients with spontaneous CSF leaks by neuro-ophthalmologists will help clarify the relation between IIH and spontaneous CSF leaks.

Spontaneous Skull Base Cerebrospinal Fluid Leaks and Their Relationship to Idiopathic Intracranial Hypertension

Background

The association between spontaneous skull base cerebrospinal fluid (CSF) leaks and idiopathic intracranial hypertension (IIH) has been suggested, but its significance remains unclear.

Objective

To estimate the prevalence of IIH in spontaneous skull base CSF leak patients.

Methods

Systematic collection of demographics, neuro-ophthalmic and magnetic resonance imaging evaluation of spontaneous skull base CSF leak patients seen pre- and post-leak repair in one neuro-ophthalmology service. Patients with preexisting IIH were diagnosed with definite IIH if adequate documentation was provided; otherwise, they were categorized with presumed IIH. Classic radiographic signs of intracranial hypertension and bilateral transverse venous sinus stenosis were recorded.

Results

Thirty six patients were included (age [interquartile range]: 50 [45;54] years; 94% women; body mass index: 36.8 [30.5;39.9] kg/m2), among whom six (16.7%, [95% confidence interval, CI]: [6.4;32.8]) had a preexisting diagnosis of definite or presumed IIH. Of the remaining 30 patients, four (13.3%, 95%CI: [3.8;30.7]) had optic nerve head changes suggesting previously undiagnosed IIH, while one was newly diagnosed with definite IIH at initial consultation. One out of 29 patients with normal findings of the optic nerve head at presentation developed new onset papilledema following surgery (3.4%, 95%CI: [0.1;17.8]) and was ultimately diagnosed with definite IIH. Overall, the prevalence of definite IIH was 19.4% (95%CI: [8.2;36.0]).

Conclusion

Striking demographic overlap exists between IIH patients and those with spontaneous CSF leak. Definite IIH was present in approximately 20% of our patients. However, its true prevalence is likely higher than identified by using classic criteria. We therefore hypothesize that an active CSF leak serves as an auto-diversion for CSF, thereby “treating” the intracranial hypertension and eliminating characteristic signs and symptoms at initial presentation.

Temporal Bone Encephaloceles: Utility of Preoperative Imaging

Objective

To determine the diagnostic efficacy and clinical value of preoperative computed tomography (CT) and magnetic resonance imaging (MRI) among patients with suspected temporal bone encephaloceles (TBE).

Study Design

Retrospective chart review from 2006 to 2018.

Setting

Tertiary referral center.

Subjects and Methods

The subjects underwent surgery for a clinically suspected TBE or cerebrospinal fluid (CSF) leak. Preoperative imaging test characteristics of CT and MRI, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were calculated for TBE scans and compared with intraoperative findings.

Results

Fifty-seven subjects with otorrhea, middle ear effusion, hearing loss, and/or meningitis with suspected TBE or CSF leak were identified. All had preoperative CT scans, and 61% (35/57) had preoperative MRI scans. Intraoperatively, 37 of 57 patients (65%) were found to have a TBE. CT scans (17% sensitivity, 100% specificity, 100% PPV, 46% NPV) were less sensitive than MRI (58% sensitivity, 100% specificity, 100% PPV, 24% NPV) for detecting TBEs. Furthermore, the time from initial scan to operative repair was significantly longer in those who had a CT followed by MRI scan compared with CT alone or a fused CT-MRI scan (mean = 68 vs 15 days, respectively; P = .004).

Conclusion

CT and MRI provide complementary information that may aid surgical planning. However, imaging cannot always rule out TBE. In cases with high clinical suspicion, surgical confirmation is often required for definitive diagnosis and treatment. The cost of an additional preoperative study should be considered before its use.

Endoscopic Endonasal Repair of Spontaneous Cerebrospinal Fluid Leaks Using Multilayer Composite Graft and Vascularized Pedicled Nasoseptal Flap Technique

Background

Endoscopic repair of cerebrospinal fluid (CSF) fistulas is a fundamental practice in anterior skull base surgery due to high success rates and low morbidity profile. However, spontaneous CSF (sCSF) leaks have the highest recurrence rate compared to other etiologies. The most effective management is undetermined due to variations in graft materials and limited evidence.

Objective

We present the largest study of a standardized endoscopic repair technique for sCSF leaks.

Methods

Single-institution retrospective review of patients who underwent endoscopic sCSF leak repair between October 2011 and January 2018. All patients underwent repair using a temporary lumbar drain, intrathecal fluorescein, and multilayer reconstruction using bilayered fascia lata autograft and vascularized nasoseptal flap.

Results

Twenty patients (100% female, mean age: 53.2 years) with 25 separate sCSF leak sites were included. Obesity was present in 15 of 20 patients (mean body mass index [BMI] = 35.3). No patients had previous sinus surgery. Locations of skull base defects included: cribriform plate (44%), ethmoid (32%), lateral sphenoid (12%), and planum sphenoidale (12%). The mean follow-up was 22.8 months and 92% of the leak sites (23/25) were successfully repaired primarily. There were no neurological complications or cases of meningitis. Two patients (mean BMI = 52) with persistent postoperative CSF leaks and elevated intracranial pressure were successfully managed with ventriculoperitoneal shunt placement. BMI was associated with likelihood of repair failure (P = .003).

Conclusions

At our institution, endoscopic repair of sCSF leaks using a composite autograft of fascia and a nasoseptal flap demonstrates high success rates. Elevated BMI was a statistically significant risk factor for revision.

Investigation of Skull-Based Cerebrospinal Fluid Leak Repair: A Single-Institution Comprehensive Study of 116 Cases Over 10 Years

BACKGROUND

Cerebrospinal fluid (CSF) leaks have been historically difficult to diagnose and treat because their cause can widely vary. There are insufficient diagnostic predictors and no clinically accepted standards for their treatment. This large institutional study reports on the diagnosis, management, and outcomes of patients presenting with CSF leak over 10 years and aims to identify potential comorbidities and risk factors for primary and recurrent leaks.

METHODS

Patients diagnosed with CSF leak from 2007 to 2017 were analyzed retrospectively. The data included medical history, body mass index, surgical treatment, and postoperative outcomes.

RESULTS

A total of 116 cases were identified. The location of leaks was 91 CSF rhinorrhea and 28 CSF otorrhea (3 both). The average BMI for females was greater than that of males (P = 0.01). Causes of leak were 64 noniatrogenic, 47 iatrogenic, and 9 traumatic. A total of 108 patients underwent surgical treatment. Sixty-nine were treated by endoscopic approaches, 42 involved open approaches, and 83 involved the placement of a lumbar drain. Eighteen patients had a ventriculoperitoneal shunt and 6 had a lumbar-peritoneal shunt. A total of 78 patients (72.22%) had an associated encephalocele with the CSF leak. The average length of stay was 7.73 days (0.76). The average length of follow-up was 1.58 years (0.22). The primary repair rate was 80.17% (n = 93) and the overall repair outcome was 99.14% (n = 115).

CONCLUSIONS

The overall CSF repair outcome was 99.14% over 10 years at a single institution. Despite this high percentage, CSF leaks continue to be a complex problem and require vigorous multidisciplinary work with close follow-up and use of multiple imaging strategies.

Incidental spontaneous CSF fistula with pterygoid process meningoencephalocele

Spontaneous cerebrospinal fluid (CSF) fistula is a rare entity, most commonly occurs at the ethmoid roof, cribriform plate, or the sphenoid sinus; at the perisella, inferolateral or pterygoid recesses. Imaging plays a major role in diagnosis, thereby guiding the treatment of a spontaneous CSF fistula, evolving multiple modalities. We report a case of a patient with spontaneous Meningio-encephalocele presented as an expansile lytic lesion in the left pterygoid body, this patient was successfully treated surgically.

Delayed presentation of morning glory disc anomaly and transsphenoidal encephalocele: A management dilemma

Background Morning glory disc anomaly (MGDA) is a rare developmental abnormality of the optic disc that is associated with many other neurological and vascular conditions. Most cases are diagnosed in childhood. Case Report We report a 57-year-old woman who presented to the ophthalmology department for assessment of long-standing poor vision in the left eye and exotropia. Examination showed a left MGDA and bitemporal hemianopsia. These findings prompted magnetic resonance imaging, revealing a transsphenoidal basal meningoencephalocele with herniation of the optic chiasm and inferior hypothalamus into the dural sac. Due to the eloquence of the neurovascular structures it contained, a decision was made not to reduce the meningoencephalocele. Instead, a ventriculoperitoneal shunt was placed. The patient's ophthalmologic examination remained stable over the following year. Conclusion While rare, MGDA can be first diagnosed in late adulthood and a thorough evaluation should be completed to assess for midline cranial defects, vascular abnormalities, and other associated abnormalities. Patients presenting late in life with basal encephalocele, herniation of the optic chiasm, and bitemporal hemianopsia present a management dilemma. In this case, a ventriculoperitoneal shunt was placed with the intention of lowering intracranial pressure to prevent further herniation and reduce the risk of cerebrospinal fluid leak.

Intervention for elevated intracranial pressure improves success rate after repair of spontaneous cerebrospinal fluid leaks

OBJECTIVES/HYPOTHESIS

Spontaneous cerebrospinal fluid (CSF) leaks are associated with increased intracranial pressure (ICP) and considered a manifestation of idiopathic intracranial hypertension. Although postoperative acetazolamide and placement of CSF shunt systems are considered valuable interventions for elevated ICP, the impact on recurrence rate remains unclear. The objective of this study was to systematically review evidence from reported literature to evaluate whether postoperative ICP management reduces recurrence rates after primary endoscopic repair.

STUDY DESIGN

Prospective case series and systematic review.

METHODS

Demographics, defect location, success rates, and ICP management in spontaneous CSF leak patients were prospectively collected over 8 years. A search was also conducted in PubMed to identify studies reporting cases of spontaneous CSF rhinorrhea.

RESULTS

Fifty-six articles with nonduplicated data were identified and combined with a prospective series of 108 patients for a total of 679 patients treated for spontaneous CSF rhinorrhea. Average age was 50.4 years with 77% female. Average body mass index was 35.8 kg/m² . Defects were most commonly located in the sphenoid sinus (n = 334) followed by the ethmoid (n = 318) and the frontal sinus (n = 46). Successful primary repair was 92.82% in patient cohorts where ICP evaluation and intervention with acetazolamide or CSF shunt systems was performed, but was significantly decreased to 81.87% in series with no active management of elevated ICP (P < .001).

CONCLUSIONS

Evaluation and intervention for elevated ICP in spontaneous CSF leaks is associated with significantly improved success rates following primary endoscopic repair.

LEVEL OF EVIDENCE

4. Laryngoscope, 127:2011-2016, 2017.

Spontaneous CSF rhinorrhea: prevalence of multiple simultaneous skull base defects

BACKGROUND

Spontaneous cerebrospinal fluid (CSF) leaks are caused by intracranial hypertension. Given this underlying etiology, patients may be at risk for developing multiple skull base defects.

OBJECTIVE

The purpose of our study is to present the prevalence of multiple simultaneous skull base defects in patients with spontaneous CSF rhinorrhea.

METHODS

We performed a retrospective chart review in a tertiary care practice of 44 consecutive patients with spontaneous CSF rhinorrhea who underwent endoscopic repair by the senior author (R.R.C.) to determine the prevalence of having multiple simultaneous skull base defects identified at the time of surgery. We defined this as two or more bony defects identified endoscopically with intact intervening bone with or without soft tissue prolapse into the nasal cavity or paranasal sinus cavity.

RESULTS

Eight of 44 patients (18.2%) were found to have multiple simultaneous skull base defects. The average body mass index (BMI) of the study population was 34.5 (range, 22.7-59).

CONCLUSION

A significant number of patients with spontaneous CSF rhinorrhea may have more than one skull base defect present at the time of presentation. The clinical significance of this finding in surgical and medical decision making is not clear at this time.

Treatment of cerebrospinal fluid rhinorrhea

PURPOSE OF REVIEW

Cerebrospinal fluid (CSF) rhinorrhea is a rare entity that can arise from a variety of causes. Successful management has been reported using a variety of repair techniques. The goal of this study is to make recommendations on intraoperative and postoperative management of CSF fistulas across all causes.

RECENT FINDINGS

Pooled analysis of case series reveals that free graft repairs are successful in closing most traumatic and iatrogenic CSF leaks. In contrast, multilayered, vascularized repairs are often required for large defects with high-flow leaks that communicate with a cistern and/or ventricles. Spontaneous CSF leaks are associated with idiopathic intracranial hypertension in the vast majority of cases, and when present, postoperative medical management is necessary for long-term success.

SUMMARY

Patients with CSF rhinorrhea require surgical repair to prevent life-threatening complications. Many techniques and materials are effective at achieving closure of CSF fistula across causes. Evidence suggests that patients with high-flow CSF fistulas have improved outcomes with multilayered, vascularized repairs to decrease the risk of postoperative CSF leaks. Patients with idiopathic intracranial hypertension need long-term management of the underlying disease process.

Endoscopic sinonasal meningoencephalocele repair: a 13-year experience with stratification by defect and reconstruction type

OBJECTIVE

Sinonasal meningoencephalocele is a rare defect, with varying etiologies and treatment strategies. Here we present the largest published series from a single institution of patients with endoscopic repair. The primary goal is to examine rates of success with consideration to accompanying patient demographic data. The secondary goal is to report the results stratified by defect and reconstruction type.

DESIGN

Retrospective consecutive case series.

SETTING

Tertiary care academic center.

SUBJECTS AND METHODS

Consecutive patients with CPT codes for skull base meningoencephalocele repair between May 2000 and March 2013 were reviewed. Patients who specifically had sinonasal defects were included.

RESULTS

During the study period, 149 cases of sinonasal meningoencephaloceles were managed in 133 patients. Mean follow-up was 21.3 months (range, 0-116). There was a success rate of 88% for initial repair, with mean recurrence time of 8.3 months (range, 0-38), and a success rate of 93.8% for initial recurrence surgery, with 99.3% of ultimate successful repair. All cases were repaired endoscopically. Recurrence rate was not significantly related to location of defect (P = .682), size of defect (P = .434), particular reconstruction technique (P = .163), or etiology (trauma, P = .070). Overall complication rate was 11.3%.

CONCLUSION

Endoscopic sinonasal meningoencephalocele repair has excellent long-term results and may be considered as a primary approach. Surgeon comfort with a particular technique should be the most important factor used to guide choice of reconstruction.

Spontaneous sphenoid sinus cerebrospinal fluid leak and meningoencephalocele - are they due to patent Sternberg's canal?

Sternberg's canal is a congenital bony defect in the lateral wall of the sphenoid sinus. If it persists to adulthood, it may become a source of spontaneous cerebrospinal fluid leak (CSF) and meningoencephalocele. The aim of the study was to describe the authors' experience and review articles related to spontaneous sphenoid sinus CSF leaks and Sternberg's canal. We analysed patients managed surgicallly due to sphenoid sinus CSF leak and performed a PubMed database search. Two female patients with spontaneous CSF leak of sphenoid origin were found. Both patients underwent surgery with the endoscopic endonasal approach, and the defect was closed using the multi-layer technique. Twelve articles related to CSF leaks of sphenoid origin (due to Sternberg's canal) were found in the PubMed database. Lines of lesser resistance within sphenoid bone may underlie CSF leak pathology together with intracranial hypertension. The endoscopic transnasal approach to the sphenoid sinus is an excellent alternative to standard transcranial procedures.

Management of spontaneous cerebrospinal fluid leaks of the sphenoid sinus: our experience

BACKGROUND

Closure of spontaneous sphenoid sinus cerebrospinal fluid leaks can be challenging because of the relative inaccessibility of the lateral recess and the presence of intracranial hypertension. We present our experience of such cases and highlight factors associated with a successful outcome.

METHODS

Eleven patients with spontaneous, laboratory confirmed, sphenoid sinus cerebrospinal fluid leaks were included. All patients underwent endoscopic closure by either a three-layer technique or fat obliteration.

RESULTS

In all but one patient, the leak was successfully sealed (success rate, 90.9 per cent; mean follow up, 37.1 months). Elevated intracranial pressure was measured in eight patients, two of whom did not exhibit relevant clinical or radiological characteristics. Five patients received diuretics and dietary advice for weight reduction. In one patient with recurrence two weeks after repair, successful revision was performed by additional placement of a ventriculoperitoneal shunt (follow up, 67 months).

CONCLUSION

Long-lasting cerebrospinal fluid fistula sealing in the sphenoid sinus requires stable reconstruction of the defect in three layers or fat obliteration if the anatomy is unfavourable. All patients should be intra- and post-operatively screened for elevated intracranial pressure to identify those who need additional intracranial pressure reduction measures.

Primary spontaneous cerebrospinal fluid leaks and idiopathic intracranial hypertension

INTRODUCTION

Idiopathic intracranial hypertension (IIH) is increasingly recognized as a cause of spontaneous cerebrospinal fluid (CSF) leak in the otolarnygological and neurosurgical literature. The diagnosis of IIH in patients with spontaneous CSF leaks typically is made a few weeks after surgical repair of the leak when symptoms and signs of elevated intracranial pressure (ICP) appear.

METHODS

Case reports and literature review. Two young obese women developed spontaneous CSF rhinorrhea related to an empty sella in one and a cribriform plate encephalocele in the other. Both patients underwent surgical repair of the CSF leak. A few weeks later, they developed chronic headaches and bilateral papilledema. Lumbar punctures showed elevated CSF opening pressures with normal CSF contents, with temporary improvement of headaches. A man with a 3-year history of untreated IIH developed spontaneous CSF rhinorrhea. He experienced improvement of his headaches and papilledema after a CSF shunting procedure, and the rhinorrhea resolved after endoscopic repair of the leak.

RESULTS

These cases and the literature review confirm a definite association between IIH and spontaneous CSF leak based on: 1) similar demographics; 2) increased ICP in some patients with spontaneous CSF leak after leak repair; 3) higher rate of leak recurrence in patients with raised ICP; 4) patients with intracranial hypertension secondary to tumors may develop CSF leak, confirming that raised ICP from other causes than IIH can cause CSF leak.

CONCLUSIONS

CSF leak occasionally may keep IIH patients symptom-free; however, classic symptoms and signs of intracranial hypertension may develop after a CSF leak is repaired, exposing these patients to a high risk of recurrence of the leak unless an ICP-lowering intervention is performed.

Obstructive sleep apnea in patients undergoing endoscopic surgical repair of cerebrospinal fluid rhinorrhea

OBJECTIVES/HYPOTHESIS

To examine the relationship between cerebrospinal fluid (CSF) rhinorrhea and obstructive sleep apnea (OSA).

STUDY DESIGN

Retrospective chart review of patients who underwent surgical repair of encephaloceles and/or CSF rhinorrhea at a tertiary medical center over a 12-year period.

METHODS

Pertinent demographic, clinical, and surgical data including age, sex, and medical and surgical history were obtained. Patients were classified by etiology of CSF leak into a spontaneous leak group and a nonspontaneous leak group, which included patients with documented trauma, malignancy, or known iatrogenic injury.

RESULTS

We retrospectively identified 126 patients who underwent repair of encephalocele or CSF rhinorrhea. Of these, 70 (55.5%) were found to have a spontaneous etiology, whereas 56 (44.4%) had a nonspontaneous cause. Patients with spontaneous CSF rhinorrhea were more likely than their nonspontaneous counterparts to have a diagnosis of OSA (30.0% vs. 14.3%, P = .0294) and radiographic evidence of an empty sella on magnetic resonance imaging MRI (55.4% vs. 24.3%, P = .0027). Overall, patients in the spontaneous CSF rhinorrhea group were more likely to be female compared to the nonspontaneous group (84.3% vs. 41.1% female, P = .0001).

CONCLUSIONS

Our study shows that patients with spontaneous CSF rhinorrhea are significantly more likely to have a diagnosis of OSA compared to those with nonspontaneous causes of CSF leaks, or to the general population (incidence of 1%-5% in various population studies). Given the known association between OSA and intracranial hypertension (ICH), it may be prudent to screen all patients with spontaneous CSF rhinorrhea for symptoms of OSA as well as for ICH, and vice versa.

LEVEL OF EVIDENCE

4

Meningoceles in idiopathic intracranial hypertension

OBJECTIVE

MRI abnormalities have been described in patients with increased intracranial pressure (ICP), including in those with idiopathic intracranial hypertension (IIH). Spontaneous CSF-filled outpouchings of the dura (meningoceles) and secondary CSF leaks can occur from elevated ICP in patients with IIH; however, few studies have evaluated these findings. Our objective was to evaluate the frequency of spontaneous intracranial meningoceles among IIH patients and determine their association with visual outcome.

MATERIALS AND METHODS

We performed a retrospective case-control study of consecutive IIH patients between 2000 and 2011 who underwent MRI that included T2-weighted imaging. Demographics, presenting symptoms, CSF opening pressure, and visual outcome were collected for the first and last evaluations. Control subjects included patients without headache or visual complaints who had normal brain MRI results. Stratified analysis was used to control for potential confounding by age, sex, race, and body mass index.

RESULTS

We included 79 IIH patients and 76 control subjects. Meningoceles were found in 11% of IIH patients versus 0% of control subjects (p<0.003). Prominent Meckel caves without frank meningoceles were found in 9% of IIH patients versus 0% of control subjects (p<0.003). Among IIH patients, the presence of meningocele or prominent Meckel caves was not associated with demographics, symptoms, degree of papilledema, CSF opening pressure, visual acuity, or visual field defect severity.

CONCLUSION

Meningoceles are significantly more common in IIH patients than in control subjects and can be considered an additional imaging sign for IIH. Meningoceles are not, however, associated with decreased CSF opening pressure or better visual outcome in IIH.

Spontaneous lateral sphenoid cephaloceles: anatomic factors contributing to pathogenesis and proposed classification

SUMMARY

Spontaneous lateral sphenoid cephaloceles arise from bony defects in the lateral sphenoid, in the absence of predisposing factors such as trauma, surgery, mass, or congenital skull base malformation. We reviewed CT and MR imaging findings and clinical data of 26 patients with spontaneous lateral sphenoid cephaloceles to better understand anatomic contributions to pathogenesis, varying clinical and imaging manifestations, and descriptive terminology. Two types of spontaneous lateral sphenoid cephaloceles were identified. In 15 of 26 patients, a type 1 spontaneous lateral sphenoid cephalocele was noted, herniating into a pneumatized lateral recess of the sphenoid sinus, and typically presenting with CSF leak and/or headache. In 11 of 26 patients, a type 2 spontaneous lateral sphenoid cephalocele was noted, isolated to the greater sphenoid wing without extension into the sphenoid sinus, presenting with seizures, headaches, meningitis, cranial neuropathy, or detected incidentally. All patients had sphenoid arachnoid pits, and 61% of patients had an empty or partially empty sella, suggesting that altered CSF dynamics may play a role in their genesis.

Temporal bone encephalocele and cerebrospinal fluid fistula repair utilizing the middle cranial fossa or combined mastoid–middle cranial fossa approach

Object

The goals of this study were to report the clinical presentation, radiographic findings, operative strategy, and outcomes among patients with temporal bone encephaloceles and cerebrospinal fluid fistulas (CSFFs) and to identify clinical variables associated with surgical outcome.

Methods

A retrospective case series including all patients who underwent a middle fossa craniotomy or combined mastoid–middle cranial fossa repair of encephalocele and/or CSFF between 2000 and 2012 was accrued from 2 tertiary academic referral centers.

Results

Eighty-nine consecutive surgeries (86 patients, 59.3% women) were included. The mean age at time of surgery was 52.3 years, and the left side was affected in 53.9% of cases. The mean delay between symptom onset and diagnosis was 35.4 months, and the most common presenting symptoms were hearing loss (92.1%) and persistent ipsilateral otorrhea (73.0%). Few reported a history of intracranial infection (6.7%) or seizures (2.2%).

Thirteen (14.6%) of 89 cases had a history of major head trauma, 23 (25.8%) were associated with chronic ear disease without prior operation, 17 (19.1%) occurred following tympanomastoidectomy, and 1 (1.1%) developed in a patient with a cerebral aqueduct cyst resulting in obstructive hydrocephalus. The remaining 35 cases (39.3%) were considered spontaneous. Among all patients, the mean body mass index (BMI) was 35.3 kg/m2, and 46.4% exhibited empty sella syndrome. Patients with spontaneous lesions were statistically significantly older (p = 0.007) and were more commonly female (p = 0.048) compared with those with nonspontaneous pathology. Additionally, those with spontaneous lesions had a greater BMI than those with nonspontaneous disease (p = 0.102), although this difference did not achieve statistical significance.

Thirty-two surgeries (36.0%) involved a middle fossa craniotomy alone, whereas 57 (64.0%) involved a combined mastoid–middle fossa repair. There were 7 recurrences (7.9%); 2 patients with recurrence developed meningitis. The use of artificial titanium mesh was statistically associated with the development of recurrent CSFF (p = 0.004), postoperative wound infection (p = 0.039), and meningitis (p = 0.014). Also notable, 6 of the 7 cases with recurrence had evidence of intracranial hypertension. When the 11 cases that involved using titanium mesh were excluded, 96.2% of patients whose lesions were reconstructed with an autologous multilayer repair had neither recurrent CSFF nor meningitis at the last follow-up.

Conclusions

Patients with temporal bone encephalocele and CSFF commonly present with persistent otorrhea and conductive hearing loss mimicking chronic middle ear disease, which likely contributes to a delay in diagnosis. There is a high prevalence of obesity among this patient population, which may play a role in the pathogenesis of primary and recurrent disease. A middle fossa craniotomy or a combined mastoid–middle fossa approach incorporating a multilayer autologous tissue technique is a safe and reliable method of repair that may be particularly useful for large or multifocal defects. Defect reconstruction using artificial titanium mesh should generally be avoided given increased risks of recurrence and postoperative meningitis.

Factors determining the clinical significance of an "empty" sella turcica

OBJECTIVE

Although often incidental, the "empty" sella turcica can reflect chronically elevated intracranial pressure (ICP). It is particularly common in the setting of idiopathic intracranial hypertension (IIH). This study evaluated which clinical and MRI findings could be used to differentiate patients with chronically elevated ICP from those with incidental empty sella turcica.

MATERIALS AND METHODS

Forty-five patients with definite IIH and 92 patients with "empty sella" reported on brain MRI were evaluated. Measurements of the sella turcica, diaphragm sella, pituitary gland, infundibulum, and scalp and neck soft tissues were made on MR images. These measurements, age, sex, clinical symptoms, and frequency of previously reported orbital findings of IIH were compared between the IIH and incidental empty sella turcica groups. Measurements on MRI were correlated with patient age in each group.

RESULTS

The IIH and incidental empty sella turcica groups had statistically similar sellar, pituitary, and infundibular measurements. The patients with IIH were significantly younger than the patients with incidental empty sella turcica (mean age, 36.1 vs 54.3 years, respectively; p < 0.05); were more likely to report headache (93.3% vs 32.6%; p < 0.05) and visual complaints (66.2% vs 28.3%; p < 0.05); showed greater mean scalp thickness (9.0 vs 6.4 mm; p < 0.05) and neck soft-tissue thickness (19.5 vs 13.8 mm; p < 0.05); and were more likely to have an orbital finding suggestive of IIH (93% vs 14%). Age modestly correlated with the width of the diaphragm sella (r = 0.53) in the IIH group only.

CONCLUSION

The significance of the MRI finding of an empty sella turcica can be determined using a combination of clinical and imaging findings.

Imaging features of idiopathic intracranial hypertension, including a new finding: widening of the foramen ovale

BACKGROUND

Idiopathic intracranial hypertension (IIH) is a clinical disorder of unknown etiology manifesting with increased intracranial pressure in the absence of hydrocephalus, an underlying mass lesion, and demonstrating normal cerebrospinal fluid composition. IIH may exhibit several non-specific imaging findings including: an empty sella, posterior globe flattening, tortuosity of the optic nerve, and optic nerve sheath distention.

PURPOSE

To introduce widening of the foramen ovale as a new imaging marker for IIH.

MATERIAL AND METHODS

IIH is a syndrome which may exhibit several previously described non-specific imaging findings including: an empty sella, posterior globe flattening, tortuosity of the optic nerve, and optic nerve sheath distention. We hypothesize that chronically elevated cerebrospinal fluid pressure can lead to osseous erosions and we propose widening of the foramen ovale as a new imaging marker for IIH.

RESULTS

Average foramen ovale sizes were increased in patients with IIH compared to controls (30.03 ± 7.00 mm(2) vs. 24.21 ± 5.97 mm(2), P < 0.001). For a cut-off value of 30 mm(2), the sensitivity of FO area to detect IIH was 50%, with 81% specificity. Classic findings were significantly more common in patients with IIH compared to controls including: empty sella (65.9% vs. 0%), posterior globe flattening (65.9% vs. 4.5%), vertical tortuosity of the optic nerve (54.5% vs. 9.1%), and optic nerve sheath distention (52.3% vs. 11.4%, all P values < 0.001).

CONCLUSION

Our study confirms the association of several classic imaging findings with IIH and supports widening of the foramen ovale as an additional imaging marker which may be incorporated into the evaluation of patients suspected to have this condition.

Spontaneous CSF Leaks

Spontaneous cerebrospinal fluid rhinorrhea represents a distinct clinic entity that is likely a variant of idiopathic intracranial hypertension (IIH). Patients with spontaneous cerebrospinal fluid (CSF) leaks are generally middle-aged obese women with radiographic evidence of skull base defects, associated meningoencephaloceles, and empty sella syndrome, a common sign of increased intracranial pressure. Significant overlap exists in the characteristics of patients with spontaneous CSF leak and IIH. Endoscopic repair of the CSF fistula is the gold standard treatment for this condition, but emerging evidence supports the reduction of CSF pressure as an important adjuvant treatment in this patient population.

Spontaneous cerebrospinal fluid rhinorrhea: a clinical and anatomical study

OBJECTIVES/HYPOTHESIS

Spontaneous nasal cerebrospinal fluid (CSF) fistula represents a rare clinical entity. The possible etiology and the localization of the rhinorrhea remain an ongoing clinical challenge. The purpose of this study was to evaluate the localization of spontaneous CSF fistula and to correlate it with anatomical studies.

STUDY DESIGN

Retrospective clinical study, prospective anatomical study.

METHODS

Twenty-nine patients with spontaneous CSF rhinorrhea were retrospectively studied, 10 males and 19 females. Ages ranged from 10 to 92 years (mean, 50 years). In addition, 48 human skulls from newborns to adults were examined for the postnatal development of the anterior and middle cranial fossa.

RESULTS

In our study isolated cribriform plate defects were found in four patients. The lateral lamina of the ethmoid bone showed defects in three patients. In nine patients the bony defect could be found in the region of the fovea ethmoidalis. The bony defect between the extra- and intracranial space was found in the lateral recess of the sphenoid sinus in eight patients. Five patients had special sites (e.g., supraorbital recess and frontal recess).

CONCLUSIONS

This study supports the theory that bony dehiscence in the lateral lamina of the ethmoid bone can be congenital and can also be spontaneously acquired later. The bony dehiscence in the lateral wall of the sphenoid sinus can only develop during pneumatization.

AGGRESSIVE INTRACRANIAL DURAL ARTERIOVENOUS FISTULA PRESENTING WITH CEREBROSPINAL FLUID RHINORRHEA

OBJECTIVE

This is the first report of an aggressive dural arteriovenous fistula presenting with rhinorrhea. It demonstrates the importance of recognizing increased intracranial pressure, and its underlying cause, as the predisposing factor to a spontaneous cerebrospinal fluid leak because this carries implications for management.

CLINICAL PRESENTATION

Ten years after minor trauma and directly after an intercontinental flight, a 43-year-old woman presented with rhinorrhea. Right-sided pulsatile tinnitus had been present for the past 9 years. Imaging demonstrated an intracranial dural arteriovenous fistula of the right transverse sinus with cortical venous reflux. Magnetic resonance imaging findings indicated long-standing increased intracranial pressure.

INTERVENTION

The fistula was treated by endovascular means, using both transvenous and transarterial approaches, which led to immediate relief of the tinnitus and resolution of the rhinorrhea within 4 days.

CONCLUSION

A dural arteriovenous fistula should be included in the differential diagnosis of underlying causes of increased intracranial pressure when examining a patient with a cerebrospinal fluid leak. Treatment of the fistula should precede attempts to treat the rhinorrhea, especially if the fistula has cortical venous reflux.

Factors contributing to failure in endoscopic skull base defect repair

BACKGROUND

Endoscopic repair of skull base (SB) defects is successful in over 90% of cases. Certain factors may contribute to failure of SB repair techniques or need for secondary repair.

METHODS

Five-year retrospective review of endoscopic SB defect repairs performed by a single surgeon.

RESULTS

Eighty-nine patients undergoing 110 procedures to repair 97 SB defects were evaluated. Etiology of defects included surgical/iatrogenic (64%), spontaneous (17%), traumatic (12%), congenital (6%), and idiopathic (1%). Defects occurred in the sella (41%), sphenoid sinus (18%), ethmoid roof (17%), olfactory cleft (16%), frontal sinus/recess (6%), and middle cranial fossa (2%). Sixty-three patients (71%) underwent primary SB defect repair and 26 patients underwent secondary repair (29%). In revision cases, mean number of prior repair attempts was 1.5 (range, 1-4). Factors potentially contributing to need for secondary SB defect repair included inability to localize SB defect (p =0 .008), development of new SB defect, prior sinus or SB surgery (p < 0.001), prior craniotomy (p < 0.001), prior radiation therapy (p = 0.002), and intracranial infection (p = 0.023). SB defects were successfully closed in 83 patients overall (93%), with success achieved in 97% of primary patients and 85% of secondary patients. Of failures, 3 patients required craniotomy for defect closure, 2 patients underwent permanent cerebrospinal fluid (CSF) diversion, and 1 patient has persistent CSF rhinorrhea.

CONCLUSION

Although endoscopic repair of SB defect remains largely successful, certain factors should alert the surgeon to the potential for failure of repair or need for secondary SB defect repair.

Acquired anterior Basal encephalocele in idiopathic hypertrophic pachymeningitis

This report describes a 49-year-old woman diagnosed as idiopathic hypertrophic pachymeningitis (IHCPM) with imaging evidence of diffuse dural sinus thrombosis. Over the years, secondary to the raised intracranial pressure, she had developed an anterior basal encephalocele through the defects in the cribriform plate of the ethmoid bone. The relation between elevated intracranial pressure and encephalocele is discussed.