Spontaneous Cerebrospinal Fluid Leak through the Posterior Aspect of the Petrous Bone

Middle ear secretions following spontaneous CSF leak repair may represent effusion rather than CSF leak

OBJECTIVE

To characterize middle ear (ME) effusion still present 2 months after repair surgery for spontaneous cerebrospinal fluid (CSF) leak via the temporal bone (TB).

STUDY DESIGN

A retrospective chart review (2011-2022).

SETTING

Tertiary referral academic center.

SUBJECTS AND METHODS

All patients with persistent ME effusion at 2 months after surgery were included in this study. The indication for surgery for spontaneous TB CSF leak was an active CSF leak with tegmen dehiscence. The presence of effusion was established by findings on microscopic otoscopy aided by tympanocentesis.ME with effusion were sampled for the presence of 𝛽2transferrin. Those negative for 𝛽2transferrin had a ventilation tube placed for ME aeration of serous otitis media (SOM). Data on persistent fluid leakage from tympanostomy tubes, presence or absence of 𝛽2transferrin in the ME, and residual air-bone gap on the postoperative audiogram were recorded.

RESULTS

Fifty-three ears underwent surgery to repair a CSF leak, 42 via a middle fossa craniotomy and 11 via transmastoid approaches. Fourteen ears (26%) still had ME effusion 2 months after surgery and it was sampled for 𝛽2transferrin. Seven were negative (SOM or mucoid OM) and the patients received a tympanostomy tube with resultant ME aeration and air-bone gap closure. The other seven underwent revision surgery.

CONCLUSIONS

Postoperative ME fluid after surgery for TB CSF leak may often represent effusion by SOM rather than an ongoing or recurrent CSF leak. ME effusion by SOM is likely caused by mucosal irritation from long-standing stagnant CSF or an underlying eustachian tube dysfunction.

Meningitis Risk and Role of Prophylactic Antibiotics in Spontaneous Lateral Skull Base CSF Leaks

OBJECTIVE

To review the literature and our institutional experience regarding the risk of meningitis in patients with spontaneous lateral skull base cerebrospinal fluid (sCSF) leaks awaiting surgical repair, and the roles of antibiotic prophylaxis and pneumococcal vaccination, if known.

METHODS

A retrospective chart review and systematic review of the literature was undertaken to identify the incidence of meningitis in patients with sCSF leaks awaiting surgical repair. Adults managed surgically for sCSF leaks at an academic tertiary care center over a 10-year period were included. Data was collected on receipt of prophylactic antibiotics and/or pneumococcal vaccines during the timeframe between diagnosis and surgical repair.

RESULTS

Institutional review identified 87 patients who underwent surgical repair of spontaneous leaks, with a 0% incidence of meningitis over a median duration of 2 months while awaiting surgery (mean 5.5 months, range 0.5-118 months). Eighty-eight percent of patients did not receive prophylactic antibiotics. No studies in the published literature demonstrated the impact of prophylactic antibiotics or pneumococcal vaccine on meningitis risk.

CONCLUSIONS

There appears to be a low risk of meningitis among patients with lateral skull base sCSF leaks awaiting surgery for short durations (≤2 months), even in the absence of prophylactic antibiotics. There is a substantial gap in the published literature assessing the risk of meningitis and roles of antibiotics and vaccination in this patient population, indicating the need for large-scale study to conclusively elucidate the nature of this risk.

Factors Predicting Cerebrospinal Fluid Leaks in Microvascular Decompressions: A Case Series of 1011 Patients

BACKGROUND

Microvascular decompression (MVD) using a retrosigmoid approach is a highly effective, open-surgical procedure for neurovascular conflict in the posterior fossa, although there is a risk of postoperative cerebrospinal fluid (CSF) leak.

OBJECTIVE

To identify factors associated with postoperative CSF leakage after MVD.

METHODS

We retrospectively reviewed all patients who underwent MVDs at our institution from 2007 to 2020. Patient demographics, clinical diagnoses, and procedural characteristics were recorded and compared. Factors leading to CSF leak were analyzed using χ 2 , univariate, and multivariate regression.

RESULTS

Of 1011 patients who underwent MVDs, 37 (3.7%) presented with postoperative CSF leaks. In univariate analysis, the use of Cranios/Norian to obliterate the air cells was protective against CSF leak ( P = .01). Craniotomies ( P = .002), the use of dural substitutes such as Durepair ( P = .04), dural onlays such as DuraGen ( P = .04), muscle/fascia ( P = .03), and titanium mesh cranioplasty >5 cm ( P = .03) were associated with CSF leak. On multivariate analysis, only the presence of craniotomies ( P = .04) and nonprimary dural closure ( P = .03) were significant risk factors for CSF leak. When excluding the 34 (3.4%) patients who underwent a craniotomy, the lack of primary dural closure still remained significantly associated with postoperative CSF leak ( P = .04).

CONCLUSION

Our results represent one of the largest series of posterior fossa surgeries for a uniform indication in North America. Our study demonstrates increased risk for postoperative CSF leak when craniotomies are performed and when primary dural closure is not established. Given the small sample of patients who received a craniotomy, however, future studies corroborating this finding should be performed.

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.

Idiopathic Intracranial Hypertension: A Comprehensive Overview

Idiopathic intracranial hypertension (IIH), also called pseudotumor cerebri syndrome, is a disorder defined as elevated intracranial pressure (ICP) of unknown cause. It is a diagnosis of exclusion in most cases, and all other forms of elevated ICP must be ruled out. With its increasing prevalence, it is much more likely for physicians, otolaryngologists included, to encounter this condition. It is important to have a clear understanding of the typical and atypical presentation of this disease, along with its evaluative workup and management options. This article reviews IIH with a focus on those factors that are specifically relevant to otolaryngologic care.

Middle Fossa Encephaloceles Treated via the Transmastoid Approach: A Case Series and Review of the Literature

BACKGROUND

Middle fossa (MF) encephaloceles are rare lesions resulting from herniation through defects in the tegmen tympani or mastoideum. Underlying etiologies and clinical presentations are variable. Surgical goals include fistula obliteration, resection of nonfunctioning parenchyma, and dehiscence repair. The middle cranial fossa approach (MCFA), transmastoid approach (TMA), and combined (MCFA + TMA) approaches have been described. The minimally invasive TMA provides excellent exposure of the pathology and allows for ample working room to repair the defect.

OBJECTIVE

We present short-term follow-up results in patients treated via the TM repair at our institution.

METHODS

A retrospective review of patients with symptomatic encephaloceles treated via the TMA by our multidisciplinary team. Patient demographics, clinical presentations, intraoperative findings, repair technique, and outcomes were highlighted.

RESULTS

A total of 16 encephaloceles in 13 patients were treated. Defect etiologies included spontaneous (50.0%), secondary to chronic infection (25.0%), or cholesteatoma (18.8%). Defects were most often within the tegmen mastoideum (68.8%). Average length of surgery was 3.3 h (95% CI: 2.86-3.67) and length of stay 3.9 d (95% CI: 3.09-4.79). On short-term follow-up (average 11.5 mo), no patients experienced postoperative cerebrospinal fluid leak or recurrence. The majority of patients (83.3%) experienced confirmed improvement or stabilization of hearing.

CONCLUSION

MF encephaloceles present with various clinical manifestations and result from multiple underlying etiologies. The TMA is an alternative to craniotomy and our short-term results suggest that this approach may be utilized effectively in appropriately selected cases.

Tissue damage in herniated brain parenchyma into giant arachnoid granulations: demonstration with high resolution MRI

BACKGROUND

Brain herniation (BH) into arachnoid granulation has been remarkable in recent years.

PURPOSE

To evaluate the damage in herniated parenchyma into the giant arachnoid granulation (GAG) and to investigate the clinical-demographic importance of this damage.

MATERIAL AND METHODS

Patients with BH into GAG were retrospectively included in the study. Each of the patients had at least one high-resolution 3D magnetic resonance imaging (MRI) sequence. The arachnoid granulation dimensions, locations, and origin of herniated parenchyma were evaluated by two experienced radiologists. The demographic and symptomatic features of the patients were recorded from the hospital database.

RESULTS

A total of 27 patients (21 females, 6 males; age range 6-71 years; mean age 41.3 years) were found to contain BH into GAG. It was most commonly seen in the transverse sinus (67%); the origin was most common in the cerebellar parenchyma (56%). Abnormal signal and morphology were detected in herniated parenchyma in 11 (47%) patients, atrophy in six, and atrophy and gliosis in five. The most common complaints were headache (47%), while other frequent symptoms were vertigo (15%) and blurred vision (11%). There was a statistically significant positive correlation between frequency of damage in herniated brain parenchyma and the maximal size of GAG (P<0.05).

CONCLUSION

In patients with BH into GAG, parenchymal damage may be associated with various symptoms, such as headache and vertigo, although they have not been statistically proven. It is important to carefully evaluate hernia tissue, as the risk of tissue damage may increase in larger GAGs.

Deossification of the Otic Bone in High Pressure CSF Otorhinorrhea: A New Radiological Finding

To highlight a new radiological feature in a patient with labyrinthine malformation presenting with bilateral spontaneous high pressure cerebrospinal fluid (CSF) otorhinorrhea. Study design-retrospective case review. Setting-academic, tertiary cochlear implant center. A cochlear implantee with Incomplete Partition Defect (Type 1) presented with meningitis and CSF otorhinorrhea for which she initially underwent medical treatment. High resolution computed tomography (HRCT) of the temporal bone with CT cisternography was performed for identifying the site of the CSF leak. HRCT and CT cisternography revealed a defect in the region of the stapes foot plate and marked thinning/deossification of the cochlear promontory. These two findings were absent in the pre-implant imaging of the patient done 3 years ago. Surgery by endaural approach was undertaken to close the site of CSF leak. Intraoperatively, marked thinning of the cochlear promontory was observed, corresponding to 'blue lining' of the labyrinth in otologic surgery. This intraoperative finding indicating high intralabyrinthine CSF pressure correlated well with the imaging findings. Primary surgical repair resulted in successful CSF leak closure followed by theco-peritoneal shunting to prevent recurrence of the leak. The patient is using her cochlear implant and doing well with auditory verbal therapy. She is asymptomatic till date. Thinning and deossification of the otic capsule on HRCT is an important indicator of high CSF pressure in patients with labyrinthine malformations. Our case study highlights the need for heightened radiological and clinical vigilance in this subgroup of patients to predict complications and ensure prompt intervention.

Cerebrospinal Fluid Leaks of the Posterior Fossa: Patient Characteristics and Imaging Features

Objective  The main purpose of this article is to investigate the prevalence and features of posterior fossa defects (PFD) in spontaneous cerebrospinal fluid leaks (sCSFL). Design  This is a retrospective case series. Setting  Tertiary skull base center. Participants  Consecutive adults undergoing lateral skull base repair of sCSFL between 2003 and 2018. Main Outcome Measures  The following data were collected: demographics, comorbidities, radiology and intraoperative findings, and surgical outcomes including complications and need for revision surgery or shunt placement. Patients with incomplete data or leaks following skull base surgery, trauma, or chronic ear disease were excluded. Results  Seventy-one patients (74% female, mean age 56.39 ± 11.50 years) underwent repair of spontaneous lateral skull base leaks. Eight ears (7 patients, 11.1%) had leaks involving the posterior fossa plate in addition to defects of the tegmen mastoideum (50%), tegmen tympani (25%), or both (25%). Patients with PFDs more often had bilateral tegmen thinning on imaging (75%, odds ratio [OR]: 10.71, 95% confidence interval [CI]: 2.20-54.35, p =  0.005) and symptomatic bilateral leaks (OR: 9.67, 95% CI: 2.22-40.17, p  = 0.01. All PFD patients had arachnoid granulations adjacent to ipsilateral mastoid cell opacification. However, this finding was often subtle and rarely included on the radiology report. There was no significant difference in body mass index, age, presenting complaints, or operative success between the PFD and isolated tegmen defect sCSFL cohorts. Conclusion  The posterior fossa is an uncommon location for sCSFL. Careful review of preoperative imaging is often suggestive and can inform surgical approach. PFD patients are similar to those with isolated tegmen-based defects in presentation, comorbidities, and outcomes.

Giant Posterior Temporal Bone Arachnoid Granulations: CT and MRI Findings

OBJECTIVE

The radiologic appearance of arachnoid granulations (AGs) in typical locations is well established and they are rarely mistaken for other pathologies. However, when large and seen in atypical locations, such as along the posterior petrous bone, AGs can be a source of diagnostic and therapeutic confusion. We present two cases of giant posterior temporal bone AGs and review their clinical presentation, potential complications, and an imaging-based differential diagnosis.

PATIENTS

Two patients with surgically or pathologically proven giant symptomatic AGs in the posterior petrous bone.

MAIN OUTCOME MEASURE

Clinical presentation, radiological features, surgical findings, and potential complications of giant AGs.

RESULTS

In two middle-aged women (37 and 55 years), computed tomography (CT) demonstrated solitary large lytic lesions in the posterior right petrous temporal bone. These were similar in appearance to cerebrospinal fluid (CSF) on magnetic resonance imaging (MRI), though they exhibited some minor deviations such as thin internal septations, mild peripheral enhancement, and heterogeneous signal on fluid-attenuated inversion recovery (FLAIR). The MRI appearance effectively distinguished the giant AGs from other lesions that can occur in this area such as endolymphatic sac tumor (ELST). Surgery was successfully performed to prevent complications from a CSF leak.

CONCLUSION

The posterior temporal bone is an atypical location for AGs and can lead to diagnostic confusion, particularly when they are large. Familiarity with the characteristic imaging appearance of giant AGs in this location can help avoid misinterpretation as a more aggressive pathology and help recognize patients who are at risk for a CSF leak.

Posterior Fossa Spontaneous Cerebrospinal Fluid Leaks

OBJECTIVE

Describe the diagnosis and management of spontaneous lateral skull base cerebrospinal fluid (CSF) leaks that originate from the posterior fossa.

STUDY DESIGN

Retrospective case review.

SETTING

Tertiary university hospital.

PATIENTS

Adult patients from 2005 to 2015 who underwent surgical repair of a spontaneous lateral skull base CSF leak with intraoperative confirmation of a posterior fossa leak source.

INTERVENTION

Surgical repair.

MAIN OUTCOME MEASURES

CSF leak resolution.

RESULTS

Five patients had CSF leaks from the posterior fossa. The mean age at presentation was 54 years old (range, 19-79), the mean body mass index (BMI) was 32.6 (standard deviation [SD], 8.4), and the mean follow-up length was 34.6 months (SD, 19.4). Presentations did not differ from CSF leaks through middle fossa defects, including three patients with a history of meningitis and all patients with clear otorrhea following tympanostomy tube placement. All patients had resolution of the leak after surgical repair, but two patients required revision surgery for persistent leaks and one patient had a postoperative infection. Surgical approaches included one middle fossa, two transmastoid, one combined middle fossa/transmastoid, and one transcanal. Radiographic studies suggested a posterior fossa source in all cases but findings were often subtle.

CONCLUSION

Posterior fossa CSF leaks represent a rare subset of spontaneous lateral skull base leaks. Diligent radiographic review and intraoperative assessment of the posterior fossa plate are crucial. The size and location of the defect dictates the optimal surgical approach. Surgeons should consider a posterior fossa source in failed repairs or when the initial surgery did not fully evaluate the posterior fossa plate.

Spontaneous defects between the mastoid and posterior cranial fossa

Conclusions Spontaneous defects between the mastoid and the posterior cranial fossa are exceedingly rare. Patients with these lesions may have a lower BMI compared to those with middle cranial fossa encephaloceles, but are otherwise demographically similar. This study recommends repair via a transtemporal approach to allow for examination of the entire posterior face of the temporal bone. Objective To describe cases of spontaneous posterior cranial fossa defects. Methods This study reviewed all cases of spontaneous posterior fossa defects presenting to a tertiary referral center over the last decade and described clinical presentation, imaging, operative findings, and outcomes. We also compared these lesions to those previously reported in the literature as well as the more common spontaneous encephaloceles of the middle cranial fossa. Results This study identified five cases with a mean age of 61.4 years, female-to-male ratio of 4:1, and a mean BMI of 31. Three cases presented with spontaneous pneumocephalus, one with CSF otorrhea, and one as an incidental imaging finding. Four defects were found medial to the sigmoid sinus and one was in the lateral retrosigmoid air cells.

"Spontaneous" CSF Fistula due to Transtegmental Brain Herniation in Combination with Signs of Increased Intracranial Pressure and Petrous Bone Hyperpneumatization: An Illustrative Case Report

Background and Importance Transtegmental brain herniation into the petrous bone is a rare cause of rhinoliquorrhea. Our case presents a combination of several typical clinical and imaging findings illustrating the ongoing etiologic discussion of such cerebrospinal fluid (CSF) fistulas.

Clinical Presentation A 53-year-old man presented with nasal discharge after a strong effort to suppress coughing. Imaging revealed a transtegmental herniation of parts of the inferior temporal gyrus into the petrous bone and in addition a combination of signs of chronically increased intracranial pressure and a hyperpneumatization of the petrous bone. The fistula was closed by a middle cranial fossa approach.

Conclusion The case illustrates the two main predisposing factors for development of petrous bone CSF fistulas: increased intracranial pressure and thinning of the tegmental roof due to extensive development of air cells. Because the CSF leakage repair does not change the underlying cause, patients have to be informed about the possibility of developing increased intracranial pressure and recurrences of brain herniations at other sites.

Recurrent meningitis secondary to a petrous apex meningocele

This case report describes a patient who was found to have a cerebrospinal fluid (CSF) leak originating from the petrous apex. The patient initially presented with multiple bouts of meningitis. The patient was treated surgically via a middle cranial fossa approach but presented five years later with recurrent meningitis and was found to have an osseous defect of the petrous apex which was not recognized prior to the initial surgery.