Impact of Obesity and Obstructive Sleep Apnea in Lateral Skull Base Cerebrospinal Fluid Leak Repair

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.

Short Postoperative Length of Stay After Lateral Cerebrospinal Fluid Leak Repair

OBJECTIVE

To characterize the short-term outcomes of patients undergoing surgical repair of lateral skull base cerebrospinal fluid (CSF) leaks followed by a shortened length of stay (LOS) protocol.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary medical center.

METHODS

A total of 156 adult patients from July 2016 to December 2022 who underwent repair of CSF leaks via transmastoid (TM), middle cranial fossa (MCF), or combined (TM/MCF) approaches were included. Data collected included: LOS, presentation to the emergency department (ED), need for readmission, major neurologic complications (stroke, seizure, and meningitis), and CSF leak recurrence.

RESULTS

Approximately half of patients underwent a TM repair (49.4%), whereas the other half underwent either an MCF (3.8%) or combined TM/MCF repair (46.8%). No peri-/postoperative lumbar drains were used and only 2 (1.3%) patients were admitted to the intensive care unit after surgery. Mean LOS for the cohort was 1.1 ± 0.7 days and was longer for surgeries involving MCF (1.3 ± 0.6) compared to TM (0.8 ± 0.7). Ninety-two percent of TM cases were discharged within 24 hours (32% on the same day) while for cases involving an MCF approach, 72.2% of patients were discharged within 24 hours. Of the patients in the study, 6 (3.8%) presented to an ED for minor complications and no patient required readmission. Revision surgery was required for 3 (1.9%) patients for recurrent CSF leak.

CONCLUSION

Our findings suggest that short LOS after surgical repair of lateral skull base defects in the treatment of CSF leak is safe and effective.

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.

Outcomes of Spontaneous Cerebrospinal Fluid Leak Repair With Concurrent Eustachian Tube Dysfunction

OBJECTIVE

To compare the presentation and outcomes of patients with and without obstructive eustachian tube dysfunction (oETD) undergoing repair of lateral skull base spontaneous cerebrospinal fluid (sCSF) leaks.

STUDY DESIGN

Retrospective chart review.

SETTING

Tertiary referral center.

PATIENTS

Adults with lateral skull base sCSF leaks who underwent repairs from January 1, 2011, to December 31, 2020, were collected.

MAIN OUTCOME MEASURE

Comparative statistics and effect sizes were used to compare clinical features, operative findings, and outcomes between groups.

RESULTS

Of 92 ears from 89 patients included, 51.1% (n = 47) had oETD. There were no differences in demographics between patients with and without oETD. Mean age was 60.7 ± 13.1 versus 58.5 ± 12.8 years ( d = -0.17 [-0.58 to 0.24]), mean body mass index was 33.8 ± 8.5 versus 36.0 ± 8.0 kg/m 2 ( d = 0.27 [-0.14 to 0.68]), and female sex preponderance was 59.6% (n = 28) versus 68.8% (n = 31; Φ = -0.09), respectively. There were no differences in the radiologic number, size, and locations of defects. Patients with oETD had less pneumatized mastoids than those without oETD ( p = 0.001; Φ = 0.43). Mean change from preoperative to postoperative air pure-tone average for those with and without oETD was -1.1 ± 12.6 versus 0.1 ± 17.2 dB ( d = 0.09 [-0.04 to 0.58]), respectively. Six ears (6.5%; three with and three without oETD) underwent revisions for rhinorrhea/otorrhea between 5 and 28 months postoperatively, during which four leaks were found, the two patients without leaks had oETD.

CONCLUSIONS

The presentation of sCSF leaks and outcomes of repairs in patients with oETD do not differ from those without oETD. Although postoperative otorrhea might represent an inflammatory or infectious process in patients with oETD, reexploration is warranted if patients do not improve with conservative treatment.

Hydroxyapatite Use in Repair of Lateral Skull Base CSF Leaks Via Transmastoid Approach: When Does It Work?

OBJECTIVE

The objective of this study is to evaluate the efficacy and outcomes of using a transmastoid approach with hydroxyapatite cement to repair lateral skull base cerebrospinal fluid (CSF) leaks.

STUDY DESIGN

Retrospective cohort study.

SETTING

Tertiary-level care hospital.

PATIENTS

Surgical patients 18 years or older between 2013 and 2022 with spontaneous CSF leak.

INTERVENTIONS

Trans-mastoid approach for skull base repair using hydroxyapatite cement.

MAIN OUTCOME MEASURES

Failure rate of repair; location and size of defect, patient demographic factors.

RESULTS

Of the 60 total defects (55 patients, 5 bilateral repairs) that underwent CSF leak repair using hydroxyapatite cement, the success rate was 91.66% (55 successful repairs). The average defect size in unsuccessful repairs was 1.15 cm compared with 0.71 cm for successful repairs. In addition, 80% (4/5) of the failed repairs were in the tegmen tympani region. Higher failure rate was noted in women (3/5) and in former smokers (4/5). Average time to recurrent symptoms was 1.75 years in the failed repair cohort. Of the patients with failed repairs, 4/5 were prescribed acetazolamide before their second procedure with successful second repair. In addition, five patients experienced postoperative headaches, three (5.4%) of whom required placement of VP shunts to relieve increased intracranial pressure. Two patients (3.6%) had complications of either infection or hearing loss.

CONCLUSIONS

Transmastoid approach utilizing hydroxyapatite is a successful approach for CSF leak repair, with a low complication and failure rate. Women, prior smoking history, and larger defects in the tegmen tympani region may need alternative materials or approach for repair. Long follow-up is warranted as recurrence of symptoms might be delayed. In cases of benign intracranial hypertension, adjuvant treatment with either acetazolamide or VP shunt placement may prevent failures.

Anterior and Lateral Skull Base Spontaneous CSF Leaks: Evaluation of Comorbidities and Treatment Outcomes

OBJECTIVES

To evaluate clinical characteristics and outcomes of patients diagnosed with anterior (ASB) or lateral skull base (LSB) spontaneous cerebrospinal fluid (sCSF) leak.

METHODS

Single center retrospective review of patients diagnosed with sCSF leaks of ASB or LSB between 1/1/2009 and 11/1/2019 (n = 69). Body mass index (BMI), gender, age at diagnosis, origin of CSF leak (ASB vs LSB), surgical approach, lumbar drain use, recurrence, pre-operative diagnosis of diabetes mellitus (DM), and obstructive sleep apnea (OSA) were collected.

RESULTS

69 patients included in this study met criteria for sCSF leak without a traumatic or iatrogenic cause (Female: 51 (74%); average BMI: 37.0 ± 7.9). Forty-eight (70.0%) presented with sCSF leaks of the lateral skull base. All ASB leaks were treated with an endoscopic transnasal approach. Eleven (22.9%) LSB leak patients were treated using transmastoid approaches and 35 (72.9%) patients with a middle cranial fossa approach. Eleven patients (15.9%) reported sCSF leak recurrence. Two patients (9.5%) with anterior skull base and 9 patients (18.8%) with lateral skull base leaks had recurrence. LSB sCSF leaks had a relative risk of 2.192 of recurrence compared to ASB leaks (95% CI: 0.431-11.157, P = .483). A 5.017 times increased risk (95% CI: 1.285-19.583, P = .020) was reported for patients with OSA, while the risks for DM and BMI were 1.351 (95% CI: 0.67-9.105, P = .177) and 1.026 (95% CI: 0.963-1.094, P = .426) respectively. Patients with sCSF leak recurrence had significantly lower lumbar drain use (33.3%) than those without recurrence (72.7%) (P = .049).

CONCLUSION

Spontaneous CSF leak recurrence is complex and multifactorial, and while patients with both DM and OSA had the higher risk of recurrence, OSA is likely an independent clinical risk factor for sCSF leak recurrence in this patient population.

Comparison of microscopic transsphenoidal surgery and neuroendoscopic transsphenoidal surgery in pituitary adenoma resection and the risk factors of postoperative cerebrospinal fluid leakage

OBJECTIVE

To compare microscopic transsphenoidal surgery (MTS) and neuroendoscopic transsphenoidal surgery (NTS) in pituitary adenoma (PA) resection and analyze the risk factors of postoperative cerebrospinal fluid leakage (CFL).

METHODS

The clinical data of 127 patients with PA treated in Xi'an International Medical Center Hospital from January 2019 to January 2021 were analyzed retrospectively. Among them, 54 patients treated by MTS for PA resection were assigned to the control group, while the rest of the 73 patients treated by NTS for PA resection were assigned to the study group. The total tumor resection rate, decrease of hormone levels after operation, alleviation of primary symptoms and complications were compared between the two groups. Logistics regression analysis was conducted to analyze the risk factors of CFL.

RESULTS

The control group experienced a shorter operation time than the study group (P<0.001). The resection rates of the control and study groups were comparable, but the study group showed a lower incidence of postoperative complications than the control group (P = 0.004). In addition, the study group showed better alleviation of primary symptoms than the control group (P = 0.013). After surgery, the two groups presented decreased levels of prolactin and growth hormone (P<0.001), and also showed decreased average adrenocorticotropic hormone (P<0.001). Moreover, the two groups were not significantly different in the levels of prolactin, growth hormone and adrenocorticotropic hormone after surgery (P>0.05). According to multivariate logistics regression analysis, body mass index (BMI) (P = 0.003, OR = 8.791, 95% CI: 2.050-37.693), intraoperative CFL (P = 0.002, OR = 21.614, 95% CI: 0.305-153.162) and therapeutic regimen (P = 0.011, OR = 7.060, 95% CI: 1.554-32.076) were independent risk factors for postoperative CFL.

CONCLUSION

Compared with MTS, endoscopic transsphenoidal surgery requires a notably longer time, but it can strongly improve the total resection rate of patients and reduce the incidence of postoperative complications. Endoscopic surgery is a protective factor of postoperative CFL.

Elevated Body Mass Index Associated with Cerebrospinal Fluid Leak after Lateral Skull Base Surgery: A Systematic Review and Meta-analysis

OBJECTIVE

To determine if body mass index (BMI) increases the risk of cerebrospinal fluid (CSF) leak after lateral skull base surgery.

DATA SOURCES

CINAHL, PubMed, and Scopus were searched from January 2010 to September 2022 for articles published in English.

STUDY SELECTION

Articles that reported BMI or obesity with and without CSF leaks after lateral skull base surgery were included.

DATA EXTRACTION

Two reviewers (F.G.D. and B.K.W.) independently performed study screening, data extraction, and risk of bias assessment.

DATA SYNTHESIS

A total of 11 studies and 9,132 patients met inclusion criteria. Meta-analysis of mean difference (MD), odds ratio (OR), proportions, and risk ratio (RR) were calculated using RevMan 5.4 and MedCalc 20.110. BMI for patients with CSF leak after lateral skull base surgery (29.39 kg/m2, 95% confidence interval [CI] = 27.75 to 31.04) was significantly greater than BMI for patients without CSF leak after lateral skull base surgery (27.09 kg/m2, 95% CI = 26.16 to 28.01) with an MD of 2.21 kg/m2 (95% CI = 1.09 to 3.34, p = 0.0001). The proportion of patients with BMI ≥ 30 kg/m2 that had a CSF leak was 12.7%, and the proportion of patients with BMI < 30 kg/m2 (control) that had a CSF leak was 7.9%. The OR for CSF leak after lateral skull base surgery in patients with BMI ≥ 30 kg/m2 was 1.94 (95% CI = 1.40 to 2.68, p < 0.0001), and the RR was 1.82 (95% CI = 1.36 to 2.43, p < 0.0001).

CONCLUSION

Elevated BMI increases the risk of CSF leak after lateral skull base surgery.

LEVEL OF EVIDENCE

IIa.

Association of Postoperative Sigmoid Sinus Occlusion and Cerebrospinal Fluid Leak in Translabyrinthine Surgery

OBJECTIVE

To characterize the incidence of sigmoid sinus occlusion (SSO) following translabyrinthine (TL) surgery for posterior fossa tumor resection and determine the association with cerebrospinal fluid (CSF) leak.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

METHODS

Patients undergoing TL surgery for vestibular schwannoma from 2012 to 2020 were included. Demographic data, medical history, preoperative tumor length and volume, and postoperative complications including CSF leak were recorded. Neuroradiology review of postoperative magnetic resonance imaging was used to determine the presence or absence of flow through the sigmoid sinus.

RESULTS

Of 205 patients undergoing TL, 21 (10.2%) experienced CSF leak postoperatively. Overall 56 (27%) demonstrated SSO on immediate postoperative magnetic resonance imaging. CSF leaks were more likely in those with SSO (19.6%) than those without SSO (6.7%; odds ratio, 3.54 [95% CI, 1.25-10.17]). Tumor volume and body mass index were not significantly associated with CSF leak. In total, 105 (51%) patients had some degree of sigmoid sinus thrombosis, but nonocclusive thrombosis was not associated with CSF leak.

CONCLUSION

SSO after TL approaches is common and appears to be significantly associated with postoperative CSF leak development. Minimizing manipulation of the sigmoid sinus during TL surgery and compression after surgery may have a role in preventing CSF leak.

An Elusive Diagnosis: Delays in Treatment and Opportunities for Improvement in Temporal Encephalocele and CSF Leak

Objective

Symptoms of temporal encephalocele or cerebrospinal fluid (CSF) leak causing middle ear effusion or otorrhea can be nonspecific and mistaken for other common diagnoses, leading to delays in diagnosis, failed treatments, and a risk of meningitis. This study sought to investigate the association between symptomatology and time to definitive surgical management.

Study Design

Retrospective cohort.

Setting

Single tertiary care academic medical center.

Patients

Adults treated surgically for temporal encephalocele or CSF leak. Revision cases were excluded.

Interventions

Chart review was performed to identify pertinent symptoms at presentation. Multivariable regression was performed to analyze the association between symptoms and time to definitive management.

Main Outcome Measures

Otologic and related symptoms present prior to middle cranial fossa (MCF). Time between symptom onset and surgical treatment.

Results

Thirty-four patients had symptoms present a median of 15.5 months (interquartile range, 8-35 months; range, 1 month to 12 years) prior to surgery. The most common symptoms were subjective hearing loss in the affected ear (76.5%) and aural fullness (73.5%). Otorrhea was present in 55.9%, and 42.9% had a history of otorrhea after myringotomy with or without tube insertion. Meningitis occurred in 5 patients (14.7%). Only the absence of otalgia was statistically significantly associated with decreased time between symptoms onset and surgery (P = 0.01).

Conclusions

Encephalocele and CSF leak were most commonly associated with aural fullness and hearing loss. Medical treatment for presumed Eustachian tube dysfunction or chronic ear disease were commonly observed. Patients had symptoms for a median of almost 1 and a half years prior to surgical management.

Frailty in middle cranial fossa approach for encephalocele or cerebrospinal fluid leak repair

Objective

The modified 5-item frailty index (mFI-5) is a concise, comorbidity-based risk stratification tool that can predict adverse outcomes after surgery. The goal of this study was to understand the frailty of patients undergoing surgery for temporal encephalocele or cerebrospinal fluid (CSF) leak and the utility of mFI-5 for predicting increased post-operative outcomes.

Methods

A retrospective review of adults with temporal encephalocele or CSF leak who underwent middle cranial fossa (MCF) approach craniotomies with or without mastoidectomy from January 2015 through August 2021 at a tertiary care academic medical center was performed. Patients who underwent additional surgeries or extended surgical approaches were excluded. The mFI-5 was calculated for all patients. Demographic and clinical data were obtained from the medical record.

Results

Thirty-six patients underwent 40 MCF approach craniotomies for temporal encephalocele or CSF leak, including three revision cases and one patient with sequential bilateral operations. Mean age was 54.1 ± 10.8 years, and 66.7% were female. In the univariable regression analysis, mFI-5 score, age, and procedure time use were significantly associated with increased hospital length of stay (LOS) but not increased intensive care unit (ICU) LOS. Anesthesia time and lumbar drain were significantly associated with increased hospital LOS and ICU LOS, and they remained significantly associated with increased hospital LOS in the multivariable model.

Conclusion

Frailty is associated with increased hospital LOS stay among patients undergoing MCF approach for CSF leak or encephalocele. Reducing anesthesia time and avoiding lumbar drain use are potentially modifiable risk factors that can reduce the LOS and associated costs.

Level of Evidence

4.

Comparison of Outcomes of Surgical Repair of Spontaneous Temporal Bone CSF Leaks and Encephaloceles Using Bone Cement and Autologous Material

OBJECTIVE

To compare outcomes transmastoid repair of spontaneous middle fossa cerebrospinal fluid (CSF) leak using only bone cement (BC) versus only autologous material (AM) or combined materials (CM) with both bone cement and autologous material.

STUDY DESIGN

Retrospective Chart Review.

SETTING

Tertiary Care Hospital.

PATIENTS

Forty-three adult patients undergoing transmastoid repair of spontaneous middle fossa CSF leak between 2014 and 2020 (BC:12, AM:15, CR:16).

INTERVENTIONS

Cortical mastoidectomy, identification of defect, and repair with BC (Cranios® hydroxyapatite), AM (local bone, fascia, fat, and/or cartilage), or CM (Cranios® combined with autologous materials).

MAIN OUTCOME MEASURES

Successful repair without recurrent CSF leak or encephalocele throughout follow up.

RESULTS

Fifty-one percent of subjects were female. Mean age at repair was 58.6 years (SD 10.9). Mean BMI was 35.4 (SD 7.6; BC:36.3, AM:36.5, CM:33.6). Forty (93%) patients had successful repair without known recurrent CSF leak or encephalocele since surgery (BC:11, 91.6%; AM:14, 93.3%; CM:15, 93.8%; p = 0.49) over a mean length of follow up of 49.6 months (BC: 37.9, AM: 59.2, CR: 49.5). The difference in mean operative time amongst the groups was faster for patients using bone cement (BC: 100.2 min, AM: 182.8, CM: 133.2; p < 0.00001).

CONCLUSIONS

BC, AM, and CM techniques each demonstrate effective and sustained means of repair for middle fossa CSF leak and encephalocele, even in the presence of multiple defects. Use of isolated BC offers a significant decrease in operative time with a noninferior outcome. Active CSF leak at the time of surgery is associated with increased risk of recurrence.

A proposed framework for cerebral venous congestion

BACKGROUND

While venous congestion in the peripheral vasculature has been described and accepted, intracranial venous congestion remains poorly understood. The characteristics, pathophysiology, and management of cerebral venous stasis, venous hypertension and venous congestion remain controversial, and a unifying conceptual schema is absent. The cerebral venous and lymphatic systems are part of a complex and dynamic interaction between the intracranial compartments, with interplay between the parenchyma, veins, arteries, cerebrospinal fluid, and recently characterized lymphatic-like systems in the brain. Each component contributes towards intracranial pressure, occupying space within the fixed calvarial volume. This article proposes a framework to consider conditions resulting in brain and neck venous congestion, and seeks to expedite further study of cerebral venous diagnoses, mechanisms, symptomatology, and treatments.

METHODS

A multi-institution retrospective review was performed to identify unique patient cases, complemented with a published case series to assess a spectrum of disease states with components of venous congestion affecting the brain. These diseases were organized according to anatomical location and purported mechanisms. Outcomes of treatments were also analyzed. Illustrative cases were identified in the venous treatment databases of the authors.

CONCLUSION

This framework is the first clinically structured description of venous pathologies resulting in intracranial venous and cerebrospinal fluid hypertension. Our proposed system highlights unique clinical symptoms and features critical for appropriate diagnostic work-up and potential treatment. This novel schema allows clinicians effectively to approach cases of intracranial hypertension secondary to venous etiologies, and furthermore provides a framework by which researchers can better understand this developing area of cerebrovascular disease.

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.

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.

Multifocal Skull Base Defects With Associated Spontaneous Cerebrospinal Fluid Leaks

OBJECTIVE

Spontaneous cerebrospinal fluid (CSF) leaks are thought to arise due to elevated intracranial pressure which is distributed across the skull base, potentially predisposing the development of multifocal CSF leaks. The aims of this study are to evaluate the characteristics of this population at presentation and surgical outcomes.

STUDY DESIGN

Retrospective case series.

SETTING

Tertiary referral center.

PATIENTS

Patients 18 years or older with spontaneous CSF leak diagnosis were eligible for study inclusion. Multifocal spontaneous CSF leak was defined as leaks originating from more than one skull base defect at anatomically distinct subsites.

INTERVENTION

None.

MAIN OUTCOME MEASURE

Clinical presentation and surgical outcome.

RESULTS

Two hundred ninety-three patients with diagnosis of spontaneous CSF leak were identified. Of these, 11 (3.8%) were characterized as having multifocal spontaneous CSF leaks. Mean body mass index was significantly higher in multifocal CSF leak patients (31.5 ± 8.5 vs 46.2 ± 9.9, p < 0.0001). There was also higher prevalence of women (100% vs 63.8%, p = 0.012) and African-Americans (63.6% vs 23.4%, p = 0.003). The overall success rate of CSF leak repair was 95%. Fifty percent of patients developed headaches or blurry vision after surgical repair, and two patients required ventriculoperitoneal shunting.

CONCLUSIONS

Multifocal spontaneous CSF leaks are rare and occurred in 3.8% of patients with spontaneous CSF. These patients were morbidly obese and more likely to be female and African American. Surgical repair conferred excellent outcomes. However, these patients have high risk of developing symptoms suggestive of elevated intracranial pressure postoperatively and should be counseled accordingly.