Can the Risks of Cerebrospinal Fluid Leak After Vestibular Schwannoma Surgery Be Predicted?

Topical tranexamic acid prevents scar tissue formation following craniectomy in a rat model

BACKGROUND

We carried out a study to assess the efficacy of tranexamic acid in preventing scar tissue in the craniectomy area in rats.

METHOD

Our study consisted of control and tranexamic acid groups with 10 subjects each. All subjects underwent bilateral frontoparietal craniectomy. After craniectomy, cotton pads were applied to the surgical sites. In the controls, the pads were soaked with saline and in the tranexamic acid group the pads were soaked with 30 mg/kg tranexamic acid. Rats were decapitated 30 days after surgery. The degree of scar formation was evaluated pathologically and by electron microscopy. In pathologic evaluation, dura mater thickness, scar tissue density, and arachnoid involvement were evaluated.

RESULTS

The outcomes demonstrated that no adhesions were present in the rats of the Tranexamic acid group, whereas the control group exhibited severe scar tissue [eight of ten rats (80%)] with adhesions. Additionally, comparison between the two groups showed that the dura mater thickness of tranexamic acid animals was thinner than that of the control group animals. Similarly, the intensity of scar tissue density and the intensity of arachnoid involvement were much better than the control group.

CONCLUSIONS

Scar tissue formation following craniectomies represents a significant adverse outcome that may lead to various complications. Intraoperative topical application of tranexamic acid has demonstrated potential efficacy in preventing scar formation in the craniectomy region in rat models.

Skull Base Repair following Resection of Vestibular Schwannoma: A Systematic Review (Part 2: The Translabyrinthine Approach)

Objectives  Despite advances in skull base reconstruction techniques, cerebrospinal fluid (CSF) leaks remain a relatively common complication after translabyrinthine (TL) vestibular schwannoma (VS) surgery. We conducted a systematic review to synthesize the repair techniques and materials used in TL VS surgery to prevent CSF leaks. Design  A systematic review of studies published since 2000 reporting techniques to prevent CSF leaks during adult TL VS surgery was conducted. A narrative synthesis of primary repair protocols was produced, and a taxonomy was established. Additionally, the advantages, disadvantages, and associated CSF leak rates of different repair protocols were extracted. Results  All 43 studies were case series, and 39 were retrospective. Repair strategies included heterogeneous combinations of autografts, xenografts, and synthetic materials. A taxonomy was produced, classifying repairs into seven distinct stages, including approaches to the dura, middle ear cleft, air cells, TL bony defect, extra-cranial soft tissue, postoperative dressings, and CSF diversion. The median postoperative incidence of CSF leaks was 6% (interquartile range: 0-10%). Conclusions  This systematic review reveals substantial inter-institutional heterogeneity in intraoperative strategies to prevent CSF leaks following TL VS surgery. However, comparing these techniques is challenging due to the multiple predictive factors for CSF leaks and their inconsistent reporting. We propose a taxonomy of seven stages to classify operative techniques and materials aimed at preventing CSF leaks. We recommend that future evaluations should adopt a prospective approach encompassing data collection strategies that considers all operative stages described by our taxonomy.

Postoperative Cerebrospinal Fluid-Related Complications After Posterior Fossa and Posterolateral Skull Base Surgeries: Development of a Predictive Model and Clinical Risk Score

BACKGROUND

Postoperative pseudomeningocele (PMC) and cerebrospinal fluid (CSF) leak are common complications following posterior fossa and posterolateral skull base surgeries. We sought to 1) determine the rate of CSF-related complications and 2) develop a perioperative model and risk score to identify the highest risk patients for these events.

METHODS

We performed a retrospective cohort of 450 patients undergoing posterior fossa and posterolateral skull base procedures from 2016 to 2020. Logistic regressions were performed for predictor selection for 3 prespecified models: 1) a priori variables, 2) predictors selected by large effect sizes, and 3) predictors with P ≤ 0.100 on univariable analysis. A final model was created by elimination of nonsignificant predictors, and the integer-based postoperative CSF-related complications (POCC) clinical risk score was derived. Internal validation was done using 10-fold cross-validation and bootstrapping with uniform shrinkage.

RESULTS

A total of 115 patients (25.6%) developed PMC and/or CSF leakage. Age >55 years (odds ratio [OR], 0.560; 95% confidence interval [CI], 0.328-0.954), body mass index >30 kg/m2 (OR, 1.88; 95% CI, 1.14-3.10), and postoperative CSF diversion (OR, 2.85; 95% CI, 1.64-5.00) were associated with CSF leak and PMC. Model 2 was the most predictive (cross-validated area under the receiver operating characteristic curve, 0.690). The final risk score was devised using age, body mass index class, dural repair technique, use of bone substitute, and duration of postoperative CSF diversion. The POCC score performed well (cross-validated area under the receiver operating characteristic curve, 0.761) and was highly specific (96.1%).

CONCLUSIONS

We created the first generalizable and predictive risk score to identify patients at risk of CSF-related complications. The POCC score could improve surveillance, inform doctor-patient discussions regarding the risks of surgery, and assist in perioperative management.

The Influence of Modifiable Risk Factors on Postoperative Outcomes in Patients Receiving Surgery for Resection for Acoustic Neuroma

Acoustic neuromas are the most common tumor of the cerebellopontine angle that are associated with a number of symptoms that negatively impact a patient's quality of life. While the mainstay of treatment for these benign tumors remains microsurgical resection, there is limited research exploring how certain modifiable risk factors (MRFs) may affect the perioperative course. The purpose of this study was to investigate how MRFs including malnutrition, obesity, dyslipidemia, uncontrolled hypertension, and smoking may affect postoperative rates of readmission and nonroutine discharges. We utilized the 2016 and 2017 Healthcare Cost and Utilization Project Nationwide Readmissions Database. MRFs were queried using appropriate International Classification of Diseases, Tenth Revision (ICD-10) coding for categories including malnutrition, obesity, dyslipidemia, smoking, alcohol, and hypertension. The statistical analysis was done using RStudio (Version 1.3.959). Chi-squared tests were done to evaluate differences between categorical variables. The Mann-Whitney U-testing was utilized to evaluate for statistically significant differences in continuous data. The "Epitools" package was used to develop logistic regression models for postoperative complications and post hoc receiver operating characteristic curves were developed. Pertaining to nonroutine discharge, predictive models using malnutrition outperformed all other MRFs as well as those with no MRFs (P < .05). In the case of readmission, models using malnutrition outperformed those of obesity and smoking (P < .05). Again, an increase in predictive power is seen in models using dyslipidemia when compared to obesity, smoking, or uncontrolled hypertension. Lastly, models using no MRFs outperformed those of obesity, smoking, and uncontrolled hypertension (P < .05). This is the first study of its kind to evaluate the role of MRFs in those undergoing surgical resection of their acoustic neuroma. We concluded that certain MRFs may play a role in complicating a patient's perioperative surgical course.

Impact of Obesity on Postoperative Complications after Lateral Skull Base Surgery: A Systematic Review

INTRODUCTION

The relationship between obesity and complications after lateral skull base tumor resection is not clear. There is conflicting evidence regarding the incidence of postoperative complications in this patient population. The purpose of this study is to examine the relationship between obesity and outcomes following lateral skull base tumor resection.

DATA SOURCES

Data were extracted from PubMed, Embase, CINAHL, and Cochrane CENTRAL.

METHODS

Included studies assessed the relationship between obesity and outcomes following lateral skull base tumor removal. Studies with ≤5 patients, pediatric patients, duplicate patient populations, or insufficient data were excluded. Two independent investigators reviewed each study for inclusion. A third reviewer served as a tie-breaker for any conflicts. Extracted data includes patient demographics, tumor pathology, surgical approach, and postoperative outcomes including incidence of cerebrospinal fluid (CSF) leak and other postoperative complications, length of stay (LOS), and readmission and reoperation rates. Descriptive statistics were used to compare postoperative outcomes for obese and nonobese controls.

RESULTS

14 studies met final inclusion criteria. Nine studies evaluated the relationship between obesity and CSF leaks. Four studies found a significant increase in postoperative CSF leak in obese patients compared to nonobese controls. The remaining studies trended toward an increased incidence of CSF leak in the obese population but did not reach statistical significance. One out of seven studies found that obesity increased postoperative LOS, and one out of five studies found that obesity increased reoperation rates following tumor resection.

CONCLUSIONS

Based on the results, obesity does not appear to increase LOS, readmission, or reoperation rates after lateral skull base tumor resection. The relationship between obesity and postoperative CSF leak, however, warrants further analysis.

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.

Risk Factors and Management of Incisional Cerebrospinal Fluid Leakage After Craniotomy: A Retrospective International Multicenter Study

BACKGROUND

Incisional cerebrospinal fluid (iCSF) leakage is a serious complication after intradural cranial surgery.

OBJECTIVE

To determine the incidence and risk factors of iCSF leakage after craniotomy. Secondarily, the complications after iCSF leakage and the success rate of iCSF leakage treatment was studied.

METHODS

All patients who underwent an intradural cranial surgery from 2017 to 2018 at 5 neurosurgical centers were retrospectively included. Data were retrieved from medical records with 2 months of follow-up. First, univariate regression analyses were performed. Subsequently, identified risk factors were evaluated in a multivariate regression analysis.

RESULTS

In total 2310 consecutive patients were included. Total iCSF leakage rate was 7.1% (n = 165). Younger age, male, higher body mass index, smoking, infratentorial surgery, and use of a dural substitute were associated with increased iCSF leakage risk, and use of a sealant reduced that risk. The odds for developing a wound infection and/or meningitis were 15 times higher in patients with iCSF leakage compared with patients without leakage. Initial conservative iCSF leakage treatment failed in 48% of patients. In 80% of cases, external cerebrospinal fluid drainage ceased the iCSF leakage. A total of 32% of patients with iCSF leakage required wound revision surgery.

CONCLUSION

iCSF leakage risk increases by younger age, higher body mass index, smoking, infratentorial craniotomy, and dural substitute use, whereas sealant use reduced the risk for iCSF leakage. The leak increases the risk of postoperative infections. When iCSF leakage occurs, immediate external cerebrospinal fluid drainage or wound revision should be considered.

Surgical Closure of the Eustachian Tube Through Middle Fossa and Transmastoid Approaches: A Pilot Cadaveric Anatomy Study

BACKGROUND

Cerebrospinal fluid rhinorrhea after temporal bone surgery involves drainage from the Eustachian tube (ET) into the nasopharynx, causing significant patient morbidity. Variable anatomy of the ET accounts for failures of currently used ET obliteration techniques.

OBJECTIVE

To describe the surgical anatomy of the ET and examine possible techniques for ET closure through middle fossa (MF) and transmastoid approaches.

METHODS

We described the surgical anatomy of the ET from the MF and transmastoid approaches in 5 adult cadaveric heads, measuring morphometric and surgical anatomy parameters and establishing targets for definite ET obliteration.

RESULTS

The osseous ET measured an average of 19.53 mm (±1.56 mm), with a mean diameter of 2.24 mm (±0.29 mm). The shortest distance between the greater superficial petrosal nerve and the ET junction was 6.61 mm (±0.61 mm). Shortest distances between the ET junction and the foramen spinosum and posterior border of the foramen ovale were 1.09 mm (±0.24 mm) and 2.03 mm (±0.30 mm), respectively. Closure of the cartilaginous ET may be performed by folding it in on itself, securing it by packing, suturing, or surgical clip ligation.

CONCLUSION

Definite obliteration of the cartilaginous ET appears feasible and the most definite approach to eliminate egress of cerebrospinal fluid to the nasopharynx using the MF approach. This technique may be used as an adjunct to skull base procedures where ET closure is planned.

Comparison of Small Intestinal Submucosal Graft and Autologous Tissue in Prevention of CSF leak after Posterior Fossa Craniotomy

Objective  To compare the use of porcine small intestinal submucosal grafts (SISG) and standard autologous material (fascia) in prevention of cerebrospinal fluid (CSF) leak and pseudomeningocele formation after translabyrinthine resection. Setting  Set at the tertiary skull base center. Methods  This is a retrospective chart review. After Institutional Review Board approval, we performed a retrospective cohort study evaluating CSF leak in patients who underwent resection of lateral skull base defects with multilayered reconstruction using either fascia autograft or porcine SISGs. Demographics were summarized with descriptive statistics. Logistic regression was used to compare autograft and xenograft cohorts in terms of CSF complications. Results  Seventy-seven patients underwent lateral skull base resection, followed by reconstruction of the posterior cranial fossa. Of these patients, 21 (27.3%) underwent multilayer repair using SISG xenograft. There were no significant differences in leak-associated complications between autograft and xenograft cohorts. Ventriculoperitoneal shunt was necessary in one (1.8%) autograft and one (4.8) xenograft cases ( p  = 0.49). Operative repair to revise surgical defect was necessary in three (5.4%) autograft cases and none in xenograft cases. Conclusion  The use of SISG as a component of complex skull base reconstruction after translabyrinthine tumor resection may help reduce CSF leak rates and need for further intervention.

Impact of extent of internal acoustic meatus tumor removal using translabyrinthine approach for acoustic neuroma surgery

Objectives

Many studies have investigated the surgical outcome and predictive factors of acoustic neuroma using different approaches. The present study focused on large tumors due to the greater likelihood of internal acoustic meatus involvement and the greater application of surgical intervention than radiosurgery. There have been no previous reports on outcomes of internal acoustic meatus tumor removal. We investigated the impact of the extent of internal acoustic meatus tumor removal using a translabyrinthine approach for large acoustic neuroma surgery and predictive factors of tumor control.

Methods

This retrospective study reviewed 104 patients with large cerebellopontine angle tumor >3 cm treated by translabyrinthine approach microsurgery. Predictive factors of postoperative facial palsy, tumor control, and extent of internal acoustic meatus tumor removal were assessed.

Results

The mean tumor size was 38.95 ± 6.83 mm. Postoperative facial function showed 76.9% acceptable function (House–Brackmann grade 1 or 2) six months after surgery. The extent of internal acoustic meatus tumor removal was a statistically significant predictor factor of poor postoperative facial function. Younger age, larger tumor size needing radiosurgery, and more extensive removal of tumor were associated with better tumor control.

Conclusion

More extensive internal acoustic meatus tumor removal was associated with poor postoperative facial function and better tumor control.

Predictors of Postoperative Complications in Vestibular Schwannoma Surgery-A Population-Based Study

OBJECTIVE

To investigate preoperative patient demographics and comorbidities in relation with postsurgical complications following vestibular schwannoma surgery.

STUDY DESIGN

Retrospective population-based cohort study.

SETTING

All hospitals in the Canadian province of Ontario.

PATIENTS

This study includes 1,456 patients who underwent vestibular schwannoma surgery from April 1, 2002 to March 31, 2018 in Ontario, Canada.

INTERVENTION/OUTCOME MEASURES

For all surgical patients, the demographic data, preoperative comorbidities, and postoperative complications were evaluated. Postoperative complications were examined immediately following surgery in the hospital as well as 1 year following the hospital discharge.

RESULTS

The most common comorbidities in this cohort were hypertension (30.22%), diabetes (9.48%), asthma (13.53%), and chronic obstructive pulmonary disease (6.73%). Diabetes was the most impactful comorbidity and was associated with higher risk of myocardial infarction (RR = 4.58, p < 0.01), pneumonia (RR = 1.80, p = 0.02), dysphagia (RR = 1.58, p < 0.01), and meningitis (RR = 3.62, p < 0.01). Analysis of surgical approaches revealed that the translabyrinthine approach, compared with the open craniotomy approach, was negatively associated with postoperative complications including pneumonia (RR = 0.43, p < 0.01), urinary tract infection (RR = 0.55, p = 0.01), dysphagia (RR = 0.66, p < 0.01), and readmission (RR = 0.45, p < 0.01).

CONCLUSION

This study examines patient demographics, preoperative comorbidities, and postoperative complications in patients who have undergone vestibular schwannoma surgery. The results highlight associations between patient characteristics and postoperative outcomes that can aid in preoperative decision-making and counselling.

Prevention of cerebrospinal fluid leak after vestibular schwannoma surgery: a case-series focus on mastoid air cells' partition

BACKGROUND

Petrous bone pneumatization may be related to cerebrospinal fluid (CSF) leak secondary to vestibular schwannoma surgery.

OBJECTIVE

To assess the association between petrous bone pneumatization and CSF leak in vestibular schwannoma surgery.

METHODS

A retrospective study included 222 consecutive vestibular schwannoma patients treated via a retrosigmoid or translabyrinthine approach in a 17-year period in one University Hospital. Association of CSF leak and petrous bone pneumatization, as seen on CT scans, was assessed on ANOVA and Student's t or Chi-squared test in case of non-parametric distribution.

RESULTS

One hundred and 75 resections were performed on a retrosigmoid approach and 47 on a translabyrinthine approach. Mean age was 53.6 ± 12.9 years. Mean follow-up was 5 years 6 months. Twenty-six patients (11.7%) showed CSF leak and 8 (3.6%) meningitis. Approach (p = 0.800), gender (p = 0.904), age (p = 0.234), body-mass index (p = 0.462), tumor stage (p = 0.681) and history of schwannoma surgery (p = 0.192) did not increase the risk of CSF leak. This risk was unrelated to mastoid pneumatization (p = 0.266). There was a highly significant correlation between internal acousticus meatus (IAM) posterior wall pneumatization and CSF leak after retrosigmoid surgery (p = 0.008). Eustachian tube packing in the translabyrinthine approach did not decrease risk of CSF leak (p = 0.571).

CONCLUSION

Degree of petrous bone pneumatization was not significantly related to risk of CSF leak, but pneumatization of the posterior IAM wall increased this risk in retrosigmoid surgery. Eustachian tube packing in the translabyrinthine approach is not sufficient to prevent postoperative CSF leak. Both approaches had similar rates of CSF leaks, around 12%.

Risk Factors for 30-Day Non-Neurological Morbidity and Cerebrospinal Fluid Leak in Patients Undergoing Surgery for Vestibular Schwannoma

Introduction  We analyzed perioperative risk factors for morbidity and mortality for the patients undergoing surgical intervention for vestibular schwannoma along with rates of cerebrospinal fluid (CSF) leaks that required surgery. Materials and Methods  Patients undergoing surgery vestibular schwannoma were identified in the American College of Surgeons National Surgical Quality Improvement Program database from 2012 to 2016 using current procedural terminology (CPT) codes for posterior fossa surgical approaches and International Classification of Diseases 9th revision (ICD 9) and ICD 10 codes for peripheral nerve sheath tumor. Preoperative laboratories, comorbidities, and operative times were analyzed along with CSF leaks and unplanned returns to the operating room. Results  Nine-hundred ninety-three patients fit the inclusion criteria. Average age was 51, 41% were male, and 58% were female. Mortality within 30 days of the operation was very low at 0.4%, complications were 7% with infection being the most common at 2.3%, and unplanned reoperations happened in 7.4% of the cases. Dependent functional status (odds ratio [OR]: 5.7, 95% confidence interval [CI]: 1.9-16.6, p  = 0.001), preoperative anemia (OR: 2.4, 95% CI: 1.2-4.5, p  = 0.009), and operative time over 8 hours (OR: 1.9, 95% CI: 1.1-3.4, p  = 0.017) were the only significant predictors of perioperative complications. CSF leak postoperatively occurred in 37 patients (3.7%). Reoperation for CSF leak was necessary in 56.3% of the cases. Operative time over 8 hours was the only independent significant predictor of postoperative CSF leak (OR: 2.2, 95% CI: 1.1-4.3, p  = 0.028). Conclusion  Dependent functional status preoperatively, preoperative anemia, and duration of surgery over 8 hours are the greatest predictors of complications in the 30-day postoperative period.

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.