Evolution of the graded repair of CSF leaks and skull base defects in endonasal endoscopic tumor surgery: trends in repair failure and meningitis rates in 509 patients

Bilaminar Chitosan Scaffold for Sellar Floor Repair in Transsphenoidal Surgery

Background

Endoscopic endonasal transsphenoidal surgery (EETS) is a standard technique used to approach sellar tumors. It is relatively safe, minimally invasive and carries a low risk of complications. However, one of the common complications reported with this technique is CSF leakage which causes morbidity, an increase in recovery time and hospital costs. This complication usually occurs from violation of the diaphragma sellae and a defect in the structures of the sellar floor or incomplete repair. In this article we report the first case with the use of a novel bilaminar chitosan scaffold which can be potentially used in the repair of the sellar floor, primarily aiming to the bony part of this structure.

Case Presentation

After a personalized design employing a tissue engineering strategy, we reconstructed the sellar floor in a 65-year-old woman who had undergone EETS for a pituitary adenoma with progressive bilateral visual loss. To repair the bony defect of the sellar floor, we used a novel bilaminar chitosan scaffold. The patient had an unremarkable postoperative course with no evidence of CSF leak. The polymer was well tolerated without toxicity, infection or complications. After 2 years of follow up the patient remains neurologically intact, and in good endocrinological status.

Conclusion

This is the first report of the use of this biomaterial and its biocompatibility in a clinical setting for the repair of the sellar floor during EETS. Our experience with chitosan bilaminar scaffold and in several preclinical studies in the literature have demonstrated good biocompatibility and effective bioengineered bone regeneration due to its excellent osteoconductive properties, this study pretends to be one landmark for further clinical research and larger case series with the use of this personalized tissue engineering materials in order to see they real efficacy to increase the surgeon armamentarium.

Surgical outcomes of the endonasal endoscopic approach within a standardized management protocol for repair of spontaneous cerebrospinal fluid rhinorrhea

OBJECTIVE

Spontaneous CSF leaks are rare, their diagnosis is often delayed, and they can precipitate meningitis. Craniotomy is the historical "gold standard" repair for these leaks. An endonasal endoscopic approach (EEA) offers potentially less invasiveness and lower surgical morbidity than a traditional craniotomy but must yield the same surgical success. A paucity of data exists studying EEA as the primary management for spontaneous CSF leaks.

METHODS

The authors retrospectively reviewed patients undergoing spontaneous CSF rhinorrhea repair at their institution from July 2010 to August 2018. Standardized management includes EEA as first-line treatment, and lumbar puncture (LP) performed 24-48 hours postoperatively. If opening pressure on LP is elevated, CSF diversion or acetazolamide therapy is used as needed. Perioperative lumbar drains are not used.

RESULTS

Of 46 patients identified, the most common CSF rhinorrhea etiology was encephalocele (28/46, 60.9%), and the most common location was cribriform/ethmoid (26/46, 56.5%). Forty-three patients underwent EEA alone, and 3 underwent a simultaneous EEA/craniotomy. The most common repair strategy was nasoseptal or other pedicled flaps (18/46, 39.1%). Postoperatively, 15 patients (32.6%) received CSF diversion due to elevated ICP, with BMI > 40 kg/m2 being a significant risk factor (odds ratio 4.35, p = 0.033) for postrepair shunt placement. Twelve patients received acetazolamide therapy for treatment of mildly elevated pressures. The average opening pressure of the shunted group was 36 cm H2O and the average for the acetazolamide-only group was 26 cm H2O. Two patients underwent CSF leak repair revision, one because of progressive fungal sinusitis and the other because of recurrent CSF leak. The mean follow-up duration was 15 months.

CONCLUSIONS

The paradigm of EEA repair of spontaneous CSF rhinorrhea with postoperative LP to identify undiagnosed idiopathic intracranial hypertension appears to be safe and effective. In the authors' cohort, morbid obesity was statistically associated with the need for postoperative CSF diversion. This has implications for future surgical treatment as obesity levels continue to rise worldwide.

How long is the tail end of the learning curve? Results from 1000 consecutive endoscopic endonasal skull base cases following the initial 200 cases

OBJECTIVE

Endoscopic endonasal approaches (EEAs) to the skull base have evolved over the last 20 years to become an essential component of a comprehensive skull base practice. Many case series show a learning curve from the earliest cases, in which the authors were inexperienced or were not using advanced closure techniques. It is generally accepted that once this learning curve is achieved, a plateau is reached with little incremental improvement. Cases performed during the early steep learning curve were eliminated to examine whether the continued improvement exists over the "tail end" of the curve.

METHODS

A prospectively acquired database of all EEA cases performed by the senior authors at Weill Cornell Medicine/NewYork-Presbyterian Hospital was reviewed. The first 200 cases were eliminated and the next 1000 consecutive cases were examined to avoid the bias created by the early learning curve.

RESULTS

Of the 1000 cases, the most common pathologies included pituitary adenoma (51%), meningoencephalocele or CSF leak repair (8.6%), meningioma (8.4%), craniopharyngioma (7.3%), basilar invagination (3.1%), Rathke's cleft cyst (2.8%), and chordoma (2.4%). Use of lumbar drains decreased from the first half to the second half of our series (p <0.05) as did the authors' use of fat alone (p <0.005) or gasket alone (p <0.005) for dural closure, while the use of a nasoseptal flap increased (p <0.005). Although mean tumor diameter was constant (on average), gross-total resection (GTR) increased from 60% in the first half to 73% in the second half (p <0.005). GTR increased for all pathologies but most significantly for chordoma (56% vs 100%, p <0.05), craniopharyngioma (47% vs 0.71%, p <0.05) and pituitary adenoma (67% vs 75%, p <0.05). Hormonal cure for secreting adenomas also increased from 83% in the first half to 89% in the second half (p <0.05). The rate of any complication was unchanged at 6.4% in the first half and 6.2% in the latter half of cases, and vascular injury occurred in only 0.6% of cases. Postoperative CSF leak occurred in 2% of cases and was unchanged between the first and second half of the series.

CONCLUSIONS

This study demonstrates that contrary to popular belief, the surgical learning curve does not plateau but can continue for several years depending on the complexity of the endpoints considered. These findings may have implications for clinical trial design, surgical education, and patient safety measures.

A Simple Onlay Sellar Reconstruction Does Not Increase the Risk of Postoperative Cerebrospinal Fluid Leak in Well-Selected Patients

Objective  A variety of endonasal sellar repair techniques have been described; many of which are complex, expensive, and carry potential morbidity but are felt to be necessary to prevent postoperative cerebrospinal fluid (CSF) leaks. We propose an effective, technically simple repair for select sellar defects utilizing an onlay of regenerated oxidized cellulose. Design  Retrospective review of patients from a single neurosurgeon who underwent endoscopic transsphenoidal surgery for pituitary adenoma and sellar reconstruction with only an onlay of regenerated oxidized cellulose. Patients were selected for this repair technique based on the absence of: (1) intraoperative identification of a CSF leak, (2) patulous diaphragm (expanded diaphragm sella herniating to or through sellar floor defect), and (3) other prohibiting comorbidities. Setting  The present study was conducted at a tertiary care center. Participants  In this study, pituitary adenoma patients were the participants. Outcome Measures  Main outcome measure of the study is postoperative CSF leak. Results  A total of 172 patients were identified. Of these, 153 were initial resections of pituitary adenomas. Gross total resection was achieved in 142 (82.6%) cases. Average tumor size was 2.2 ± 1.1 cm. Average tumor volume was 10.4 ± 19.8 cm ³ . No patients had intraoperative CSF leaks. All cases were repaired with only an onlay of regenerated oxidized cellulose. There were two postoperative CSF leaks (1.16%). Pre and postoperative SNOT-22 scores were 12.9 ± 11.9 and 14.3 ± 14.9 ( p  = 0.796), respectively. Conclusion  The use of an onlay of regenerated oxidized cellulose alone is an effective repair technique for select sellar defects. This technique does not result in increased postoperative CSF leak rates and avoids the higher relative cost and potential morbidity associated with more complex, multilayered closures.

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

OBJECTIVE

CSF leakage is a potentially fatal condition that may result when a skull base dural defect permits CSF communication between the cranial vault and sinonasal cavities. Flow rate is an important property of CSF leaks that can contribute to surgical decision-making and predispose patients to complications and inferior outcomes. Noninvasive preoperative prediction of the leak rate is challenging with traditional diagnostic tools. The present study compares fluid configurations on early and late volumetric extended echo train T2-weighted MRI by using image tracings and sequence subtraction as a novel method of quantifying CSF flow rate, and it correlates radiological results with intraoperative findings and clinical outcomes.

METHODS

A total of 45 patients met inclusion criteria for this study and underwent 3-T MRI. Imaging sequences included two identical CUBE T2 (vendor trade name for volumetric extended echo train T2) acquisitions at the beginning and end of the scanning session, approximately 45 minutes apart. Twenty-five patients were confirmed to have definitive spontaneous or traumatic anterior skull base CSF leaks. Semiautomated volumetric segmentation of CSF intensity was performed on both CUBE data sets by using 3D-Slicer software, and volumes were subtracted to obtain accumulated CSF volume. These imaging-derived fluid accumulations were correlated with high- or low-flow states, as well as ultimate treatment outcomes including recurrences.

RESULTS

Of the 45 patients, 25 (55.6%) had definitive evidence of CSF leakage, and 22 (88%) of these underwent surgical repair. Patients with high-flow CSF leaks had higher early (4.058 cm3 vs 0.982 cm3, p = 0.04), late (4.58 cm3 vs 1.096 cm3, p = 0.04), and accumulated (0.53 cm3 vs 0.11 cm3, p = 0.01) fluid volume measurements than patients with low-flow leaks. The 5 (22.7%) patients who exhibited postoperative CSF leak recurrence had significantly greater early (6.30 cm3 vs 1.23 cm3, p = 0.008) and late (6.87 cm3 vs 1.45 cm3, p = 0.008) volumes. Accumulated volume was not significantly greater in patients with leak recurrence (0.58 cm3 vs 0.22 cm3, p = 0.07). Early, late, and accumulated volumes were significantly correlated with postoperative hospital stay as well as duration of postoperative lumbar drain placement (p < 0.05 for all measures).

CONCLUSIONS

High-resolution CUBE T2 MRI, coupled with precise volumetric segmentation and subtraction of sinonasal hyperintensity, not only demonstrated predictive value in differentiating low- and high-flow CSF leaks, but also correlated with postoperative complications such as leak recurrence. These findings may be useful in the clinical workup and neurosurgical management of patients with skull base CSF leaks.

Continuous dural suturing for closure of grade 3 leaks after tumor removal via an endoscopic endonasal approach

Cerebrospinal fluid (CSF) leakage is a major complication after extended endonasal transsphenoidal surgery (EETSS), which is commonly used in the treatment of anterior skull base tumors. Dural suturing and graded reconstruction are promising techniques to further decrease the incidence of postoperative CSF (poCSF) leakage. The effect of continuous dural suturing in endoscopic surgery was investigated in this retrospective study. A total of 79 EETSS patients were included; the procedures were performed for subdural tumor removal by a single endoscopic neurosurgical team. Comparisons were applied between patients who did and did not undergo endoscopic dural suturing after tumor removal. Multivariate logistic regression analysis was performed to identify variables that significantly influenced the incidence of poCSF leakage. In all, 79 adult patients developed Esposito's grade 3 intraoperative high-flow CSF leakage. Ten patients (12.7%) experienced poCSF leakage. One of the 36 patients who underwent intraoperative dural suturing developed poCSF leakage, compared with nine of 43 patients who did not undergo dural suturing (p = 0.016). Regression analysis showed that dural suturing could significantly decrease the incidence of poCSF leakage (p = 0.049, OR 0.108, 95% CI 0.013-0.899). Prophylactic lumbar drainage could also help decrease the CSF leakage rate. Dural suturing under endoscopy is a promising and effective method for application in skull base reconstruction after subdural skull base tumor removal. With future progress, lumbar drainage and even nasoseptal flap placement could be replaced in certain groups of patients undergoing EETSS.

Infectious Complications of Expanded Endoscopic Transsphenoidal Surgery: A Retrospective Cohort Analysis of 100 Cases

Objective  To identify perioperative factors that may predict postoperative cerebrospinal fluid (CSF) leak and meningitis following expanded endoscopic transsphenoidal surgery (EETS). Study Design  This is a retrospective study. This study was set at the Cedars-Sinai Medical Center, Los Angeles. A total of 78 patients who underwent EETS between January 2007 and November 2018 were participated. The main outcome measures were CSF leak and meningitis. Results  A total of 78 patients underwent a total of 100 EETS procedures; 17.9 and 10.3% of patients developed postoperative CSF leaks and meningitis, respectively. Out of eight, three patients with meningitis did not develop an observable CSF leak. The risk of developing meningitis in patients with a CSF leak was significantly higher than those without a leak, with an odds ratio (OR) of 11.48 (95% confidence interval, 2.33-56.47; p  = 0.004). Pituicytomas were significantly associated with meningitis compared with other pathologies. No other patient-specific factors were identified as risks for leak or meningitis, including method of skull base repair, sex, tumor volume, or body mass index, although there was a strong trend toward reduced CSF leak rates in patient with nasoseptal flaps used for skull base repair, compared with those without (9.5 vs. 25%). CSF protein was consistently elevated on the first CSF values obtained when meningitis was suspected. Conclusion  CSF leak and meningitis are common complications of expanded endonasal surgery No statistically significant risk factors for developing a postoperative leak other than the pathology of pituicytoma were identified, including method of skull base repair, although the use of a vascularized nasoseptal flap did trend toward a reduced CSF leak rate. CSF protein is the most sensitive marker for the presumptive diagnosis and timely treatment of meningitis.

Rathke's cleft cysts: a 6-year experience of surgery vs. observation with comparative volumetric analysis

BACKGROUND

Rathke's cleft cysts (RCCs) are common sellar lesions. Their management remains controversial, particularly when small or asymptomatic. Herein we review a consecutive series of RCC patients managed with surgery or observation.

METHODS

All patients with a new diagnosis of presumed RCC, based on MRI, from February 2012-March 2018 were retrospectively divided into observational and surgical cohorts based on an intent-to-treat model. The cohorts were compared for clinical presentation, and cyst volume. The observational cohort was followed for change in cyst size. The surgical cohort was followed for changes in endocrinopathy, visual symptoms, headache and recurrence.

RESULTS

Of 90 patients (mean age 36.7 ± 19.4 years; 68% female), 60% (n = 54) were in the observational cohort and 40% (n = 36) in the surgical cohort. Average follow-up was 13 ± 23 months in the observational cohort and 24 ± 19 months in the surgical group. In comparing the cohorts, mean ages were similar with more women in the surgical group (81% vs. 56%, p = 0.04). Most patients in the observational cohort had incidentally-discovered RCCs (n = 50, 88%) as opposed to the surgical cohort (n = 6, 17%). The surgical cohort had higher rates of headache (89% vs 26%, p < 0.001), endocrinopathy (36% vs 0%, p < 0.001), and visual dysfunction (19% vs 0%, p = 0.001). Mean cyst volume and maximal cyst dimensions were greater in the surgical cohort (0.94 ± 0.77 cm³ and 14.2 ± 4.1 mm), compared to the observational cohort (0.1 ± 0.14 cm³ and 6.4 ± 3 mm), (p < 0.001). Among the 53% (n = 30/54) of patients in the observational group with follow-up, 3 (10%) had spontaneous RCC shrinkage, 1 (3%) had modest asymptomatic growth (at 10 months from initial MRI), and 87% had stable cyst size. Of the 36 patients recommended to have surgery, 89% (n = 32) did so. Post-operatively, complete or partial resolution of headache, endocrinopathy and visual dysfunction were documented in 90% (n = 28/30), 75% (n = 10/12), and 100% (n = 7/7), respectively. On follow-up MRI, 8 (22%) patients had some cyst reaccumulation, of whom 3 (8%) were symptomatic and underwent uneventful reoperation. No major complications such as hematoma, CSF leak, new endocrinopathy or visual deficits occurred.

CONCLUSION

From this consecutive series, a majority (60%) of RCCs do not appear to warrant surgical intervention and have a low risk of cyst progression. However, surgical cyst removal appears to be indicated and safe for patients with larger, symptomatic RCCs. Simple cyst drainage has a high rate of improvement in pituitary gland function, visual function and headache resolution with low complication rates and symptomatic recurrence risk. These findings stress the importance of careful case selection and potential utility of volumetric assessment for patients with RCCs.

Neural network-based identification of patients at high risk for intraoperative cerebrospinal fluid leaks in endoscopic pituitary surgery

OBJECTIVE

Although rates of postoperative morbidity and mortality have become relatively low in patients undergoing transnasal transsphenoidal surgery (TSS) for pituitary adenoma, cerebrospinal fluid (CSF) fistulas remain a major driver of postoperative morbidity. Persistent CSF fistulas harbor the potential for headache and meningitis. The aim of this study was to investigate whether neural network-based models can reliably identify patients at high risk for intraoperative CSF leakage.

METHODS

From a prospective registry, patients who underwent endoscopic TSS for pituitary adenoma were identified. Risk factors for intraoperative CSF leaks were identified using conventional statistical methods. Subsequently, the authors built a prediction model for intraoperative CSF leaks based on deep learning.

RESULTS

Intraoperative CSF leaks occurred in 45 (29%) of 154 patients. No risk factors for CSF leaks were identified using conventional statistical methods. The deep neural network-based prediction model classified 88% of patients in the test set correctly, with an area under the curve of 0.84. Sensitivity (83%) and specificity (89%) were high. The positive predictive value was 71%, negative predictive value was 94%, and F1 score was 0.77. High suprasellar Hardy grade, prior surgery, and older age contributed most to the predictions.

CONCLUSIONS

The authors trained and internally validated a robust deep neural network-based prediction model that identifies patients at high risk for intraoperative CSF. Machine learning algorithms may predict outcomes and adverse events that were previously nearly unpredictable, thus enabling safer and improved patient care and better patient counseling.

Strategy and Technique of Endonasal Endoscopic Bony Decompression and Selective Tumor Removal in Symptomatic Skull Base Meningiomas of the Cavernous Sinus and Meckel's Cave

BACKGROUND

Parasellar meningiomas involving the cavernous sinus and Meckel's cave pose a management challenge because of invasion around neurovascular structures and the pituitary gland. The management options range from aggressive resection to focused radiotherapy alone. We present a strategy for these tumors that includes endonasal bony decompression, partial tumor removal, and stereotactic radiotherapy (SRT) in select cases.

METHODS

The tumor location, previous treatments, cranial neuropathies, pituitary dysfunction, tumor control rates, use of stereotactic radiosurgery, SRT, and complications were retrospectively evaluated.

RESULTS

Twenty patients (age range, 43-81 years; 65% women; 90% with World Health Organization grade I; median follow-up, 57 months; 14 without previous debulking and RT; 6 with previous debulking and RT) underwent endonasal bony decompression and partial tumor removal. The most common tumor locations were cavernous sinus (95%), Meckel's cave (95%), sella (75%), petroclival (60%), and optic canal/orbit (30%). Three patients with large meningiomas underwent staged transcranial and endonasal debulking. Of the 14 patients without previous debulking and RT, 11 had undergone postoperative SRT, with tumor shrinkage in 3 (27%). At the last follow-up examination, for these 14 patients and the 6 patients who had undergone previous surgery and RT, tumor control was 100% and 33% (P < 0.001) and the cranial neuropathies had improved in 57% and 33%, respectively. Major complications occurred in 2 patients: a permanent sixth cranial nerve palsy and cerebrospinal fluid leakage requiring reoperation.

CONCLUSIONS

Endonasal bony decompression and selective tumor removal, followed by SRT, appears to be a reasonable treatment option for most previously untreated parasellar meningiomas. For patients who have undergone previous debulking and RT, new targeted treatment strategies are needed.