The learning curve in endoscopic endonasal resection of craniopharyngiomas

The learning curve in endoscopic transsphenoidal skull-base surgery: a systematic review

BACKGROUND

The endoscopic endonasal transsphenoidal approach (EETA) has revolutionized skull-base surgery; however, it is associated with a steep learning curve (LC), necessitating additional attention from surgeons to ensure patient safety and surgical efficacy. The current literature is constrained by the small sample sizes of studies and their observational nature. This systematic review aims to evaluate the literature and identify strengths and weaknesses related to the assessment of EETA-LC.

METHODS

A systematic review was conducted following the PRISMA guidelines. PubMed and Google Scholar were searched for clinical studies on EETA-LC using detailed search strategies, including pertinent keywords and Medical Subject Headings. The selection criteria included studies comparing the outcomes of skull-base surgeries involving pure EETA in the early and late stages of surgeons' experience, studies that assessed the learning curve of at least one surgical parameter, and articles published in English.

RESULTS

The systematic review identified 34 studies encompassing 5,648 patients published between 2002 and 2022, focusing on the EETA learning curve. Most studies were retrospective cohort designs (88%). Various patient assortment methods were noted, including group-based and case-based analyses. Statistical analyses included descriptive and comparative methods, along with regression analyses and curve modeling techniques. Pituitary adenoma (PA) being the most studied pathology (82%). Among the evaluated variables, improvements in outcomes across variables like EC, OT, postoperative CSF leak, and GTR. Overcoming the initial EETA learning curve was associated with sustained outcome improvements, with a median estimated case requirement of 32, ranging from 9 to 120 cases. These findings underscore the complexity of EETA-LC assessment and the importance of sustained outcome improvement as a marker of proficiency.

CONCLUSIONS

The review highlights the complexity of assessing the learning curve in EETA and underscores the need for standardized reporting and prospective studies to enhance the reliability of findings and guide clinical practice effectively.

Factors predicting outcomes of endoscopic endonasal approach in craniopharyngioma patients

Objectives

Endoscopic endonasal approach (EEA) is commonly used for resection of craniopharyngioma (CP). Treatment outcomes of EEA for CP were related to numerous factors; however, they have been evaluated in few studies. The objective of this study is to investigate factors associated with the outcomes of CP following this operation.

Materials and Methods

The records of patients with CP, who underwent EEA at our institution from January 2014 to June 2022, were retrospectively reviewed. Surgical outcomes, including the extent of resection, visual recovery, and endocrinological outcomes, were reported. Clinical and radiographic factors were analyzed for their associations with treatment outcomes using logistic regression analyzes.

Results

This study cohort consisted of 28 patients with CP. Gross total resection (GTR) was achieved in 12 patients (43%). Post-operative visual status improved, stabilized, and deteriorated in 89%, 6%, and 6% of the patients, respectively. There were no patients recovered from pre-operative pituitary dysfunctions, while post-operative hypoadrenalism, hypothyroidism, and hypogonadism were found in 9 (36%), 11 (42%), and 4 (22%) patients, respectively. Post-operative permanent diabetic insipidus was found in 13 patients (50%). Greater suprasellar extension of the tumor was associated with a lower rate of GTR (P = 0.011). Diabetes mellitus (DM) was associated with poor visual recovery (P = 0.022). Larger tumor size and Puget grade 2 were associated with postoperative hypoadrenalism (P = 0.01 and 0.023, respectively). In addition, Puget grade 2 was associated with post-operative hypothyroidism (P = 0.017).

Conclusion

For EEA in CP, the extent of resection could be determined by suprasellar extension of the tumor. DM was a poor predicting factor for visual recovery, while larger tumors and Puget grade 2 had a higher risk of post-operative hypopituitarism.

Endoscopic cadaveric analysis of the origin of the ophthalmic artery

PURPOSE

The ophthalmic artery is often involved in suprasellar and parasellar surgeries, but the anatomical structure where the ophthalmic artery originates has not been fully clarified from the perspective of an endoscopic endonasal approach (EEA).

METHODS

A total of 10 fresh cadaveric heads (20 sides) were dissected through an EEA, and the origin of the bilateral ophthalmic arteries and their adjacent structures were observed from a ventral view. The origin of the ophthalmic artery in 50 healthy people was retrospectively studied on computed tomography angiography imaging.

RESULTS

The ophthalmic artery originated from the intradural segment (75%), paraclinoid segment (15%), or parasellar segment (10%) of the internal carotid artery. The cross-sectional view of the internal carotid artery through the EEA showed that the ophthalmic artery originated from the middle 1/3 (75%) or medial 1/3 (25%) of the upper surface of the internal carotid artery. On computed tomography angiography, the ophthalmic artery originated from the middle 1/3 (77%) and medial 1/3 (22%) of the upper surface of the internal carotid artery. All ophthalmic arteries were near the level of the distal dural ring (DDR) of the internal carotid artery, that is, within 3 mm above or below the DDR.

CONCLUSIONS

The ophthalmic artery usually originates in the middle 1/3 of the upper surface of the intradural segment of the internal carotid artery within 3 mm of the DDR. The ophthalmic artery can be protected to the utmost extent after its origin is identified through an EEA.

A Full View of Papillary Craniopharyngioma Based on Expanded Endonasal Approach: A Comprehensive Clinical Characterization of 101 Cases

OBJECTIVE

The enlarged endonasal approach (EEA) has emerged as the preferred surgical procedure for removing craniopharyngiomas, due to its advantages of direct visualization and reduction of blind corners. However, owing to a low incidence of papillary CPs (PCPs) compared to adamantinomatous CPs (ACPs), a full view of PCP based on the EEA approach is limited. In this paper, the authors present the largest series to date analyzing the clinical characteristics based on the EEA approach for PCPs.

METHODS

A retrospective review was conducted on 101 PCPs patients who underwent endoscopic endonasal surgery (EEA) and whose condition was confirmed via postoperative pathology. The PCPs were classified into three types based on MRI data and intraoperative findings from EEA: suprasellar/intra-suprasellar (3V floor intact) type (Type I), suprasellar/intra-suprasellar (3V floor invasive) type (Type II), and intra-third ventricle type (Type III). The general characteristics of the three types of tumors were summarized, and postoperative follow-up was conducted to record detailed information on changes in vision, endocrine replacement, tumor recurrence, and quality of life.

RESULTS

Out of the 101 cases, 36 (36.64%) were classified as type I, 52 (51.49%) as type II, and 13 (12.87%) as type III. The mean age of type III patients was 40.46 ± 14.15 years old, younger than the other two types (p = 0.021). Headache (84.62%) and memory decline (61.54%) were prominent features in patients with type III (p = 0.029). Visual impairment was more common in type II (80.77%, p = 0.01). Gross total resection (GTR) was achieved in 91 patients (90.10%). There were no significant differences in GTR rates among the three types of tumors. There were significant differences in quality of life among the three types of PCP (p = 0.004), and type III presented with the highest rate of good postoperative quality of life (92.31%) based on the KPS score. Thirteen (12.87%) tumors recurred within a mean follow-up time of 38 (range, 8-63) months. Type II PCPs (OR 5.826, 95%CI 1.185-28.652, p = 0.030) and relapsed patients (OR 4.485, 95%CI 1.229-16.374, p = 0.023) were confirmed as independent risk factors for tumor recurrence.

CONCLUSIONS

Most of the PCPs including intra-third ventricle PCPs can be safely and effectively removed through neuroendoscopy with EEA. Suprasellar/intra-suprasellar (third cerebral ventricle floor-invasive) type PCPs may have a worse postoperative quality of life compared to the other two types, and it may be a strong predictor of tumor recurrence.

Efficacy of hydroxyapatite-based skull base reconstruction for intraoperative high-flow cerebrospinal fluid leakage performed by less-experienced surgeons

Cerebrospinal fluid (CSF) leakage after endoscopic skull base surgery remains a challenge despite multilayer reconstruction including nasoseptal flap (NSF) has become a standard technique. Injectable hydroxyapatite (HXA) has shown promising results to prevent CSF leakage. This study aimed to validate the efficacy of HXA-based skull base reconstruction performed by less-experienced neurosurgeons who had short-term clinical experiences as independent surgeons. Between March 2018 and November 2022, 41 patients who experienced intraoperative high-flow CSF leakage following endoscopic endonasal surgery at two independent tertiary institutions were enrolled. Skull base reconstruction was performed using conventional multilayer techniques combined with or without HXA. The primary outcome was postoperative CSF leakage. The surgical steps and nuances were described in detail. The most common pathology was craniopharyngioma. Injectable HXA was used in 22 patients (HXA group) and conventional techniques were performed in 19 patients (control group). The HXA group achieved a significantly lower incidence of postoperative CSF leakage than the control group (0% vs. 26.3%, p = 0.016). No HXA-related complications were observed. The use of injectable HXA in skull base reconstruction was highly effective and safe. This technique and its favorable results might be readily reproduced by less-experienced neurosurgeons.

Comparing Surgical Approaches for Craniopharyngioma Resection Among Adults and Children: A Meta-analysis and Systematic Review

BACKGROUND

Craniopharyngioma treatment often necessitates surgical resection. Conventional approaches, such as transcranial and transsphenoidal approaches, are predominantly used. However, a recently adopted supraorbital approach may be more efficacious. Thus, this meta-analysis and systematic review aimed to compare the efficacy of the transcranial, transsphenoidal, and supraorbital approaches for resection and treatment of craniopharyngiomas.

METHODS

This study was performed following PRISMA guidelines. Analyses were performed according to study design: (1) analyses for studies comparing several surgical approaches; and (2) analyses of all included studies. Random effects meta-analysis models were used to pool odds ratios among studies comparing several approaches. Similarly, categorical meta-regression models were used to examine the effect of surgical approach as a covariate of outcome data for all studies. Statistics were performed using Comprehensive Meta-Analysis software (CMA 3.3, Biostat, Englewood, NJ) (significance set at P < 0.05).

RESULTS

Patients were well-matched for age, sex, and preoperative comorbidities between groups stratified by surgical approach. Analyses including 22 studies that compared several approaches demonstrated that the transsphenoidal group had a greater occurrence of postoperative visual improvement (P < 0.0001), lesser occurrence of visual deterioration (P < 0.0001), and lower tumor recurrence rate (P = 0.015) compared with the transcranial group. Only 2 studies compared the supraorbital approach to another approach, limiting analyses. Analyses including all studies demonstrated that the supraorbital group did not differ to either the transcranial or transsphenoidal group for any examined variables.

CONCLUSIONS

The present study suggests that the transsphenoidal approach is associated with improved clinical outcomes for craniopharyngioma resection. There are limited data regarding the supraorbital approach, warranting future investigation.

Predictors of the Spontaneous Resolution of Central Diabetes Insipidus Following Endoscopic Endonasal Surgery for Craniopharyngioma

OBJECTIVE

Central diabetes insipidus (CDI) is the most common complication of endoscopic endonasal surgery (EES) for craniopharyngioma. However, some cases of CDI could spontaneously resolve during the follow-up period. Hence, this study aimed to determine the predictive factors for the spontaneous resolution of CDI.

METHODS

Data of patients with CDI who underwent EES for craniopharyngioma between February 2009 and June 2021 were retrospectively reviewed. All patients were divided into 2 groups based on the resolution of CDI during follow-up: the recovery and no recovery groups. The baseline characteristic, surgical, and follow-up results of patients were compared.

RESULTS

We identified 84 patients with CDI (35 in the recovery group and 49 in the no recovery group). A direct comparison showed that retaining the pituitary stalk (57.1% vs. 14.3%, P = 0.000) and no-hypothalamic injury (HI) (68.6% vs. 20.4%, P = 0.000) were more common in the recovery group, whereas hydrocephalus at diagnosis (8.6% vs. 46.9%, P = 0.000) was significantly more common in the no recovery group. Subsequently, we found through univariate and multivariate analysis that the spontaneous resolution of CDI was associated with hydrocephalus at diagnosis (yes vs. no: odds ratio [OR], 0.198; P = 0.045), pituitary stalk injury (retaining vs. sectioning: OR, 7.055; P = 0.004), and the Hong et al HI pattern (mild-HI vs. no-HI: OR, 0.183; P = 0.038; unilateral-HI vs. no-HI: OR, 0.147; P = 0.017; bilateral-HI vs. no-HI: OR, 0.154; P = 0.044).

CONCLUSIONS

Hydrocephalus at diagnosis, pituitary stalk injury, and the Hong et al HI pattern might be predictors of the spontaneous resolution of CDI following EES for craniopharyngioma.

Endoscopic versus Nonendoscopic Surgery for Resection of Craniopharyngiomas

OBJECTIVE

While surgery is a critical treatment option for craniopharyngiomas, the optimal surgical approach remains under debate. Herein, we studied a large cohort of craniopharyngioma patients to identify predictors of endoscopic surgery (ES) and to compare survival outcomes between patients undergoing ES versus nonendoscopic surgery (NES).

METHODS

The National Cancer Database was queried for patients receiving definitive surgical treatment in 2010-2016. Cox proportional hazards and propensity score-adjusted Kaplan-Meier analyses assessed mortality risk and overall survival, respectively. Predictors of surgical approach were evaluated via logistic regression.

RESULTS

Of 1721 patients, 508 (29.5%) underwent ES, 877 (50.9%) were female, and the average age was 41.8 ± 21.3 years. Matched ES and NES cohorts exhibited 5-year overall survival rates of 88.0% and 79.8%, respectively (P = 0.004). ES was associated with reduced mortality (Hazard Ratio = 0.634; 95% confidence interval [CI], 0.439-0.914; P = 0.015). Patients treated at academic facilities (Odds Ratio [OR] = 2.095; 95% CI, 1.529-2.904; P < 0.001) or diagnosed recently (OR = 1.132; 95% CI, 1.058-1.211; P < 0.001) were more likely to undergo ES, while those with tumor sizes >3 cm (OR = 0.604; 95% CI, 0.451-0.804; P < 0.001) or receiving adjuvant radiotherapy (OR = 0.641; 95% CI, 0.454-0.894; P = 0.010) were more likely to receive NES. Surgical inpatient stays were significantly shorter with ES compared to NES (8.0 vs. 10.5 days, P < 0.001). On linear regression, ES usage increased by 82.4% and NES usage decreased by 23.4% between 2010 and 2016 (R² = 0.575, P = 0.031).

CONCLUSIONS

ES of craniopharyngioma was associated with reduced mortality and shorter inpatient stays compared to NES. Factors including tumor size, extent of resection, facility type, and year of diagnosis may predict receiving ES. There is a trend towards increased usage of ES for surgical management of craniopharyngiomas.

The Influence of Facility Volume and Type on Skull Base Chordoma Treatment and Outcomes

OBJECTIVE

To evaluate the influence of facility case volume and type on skull base chordoma treatment and overall survival (OS).

METHODS

The 2004-2016 National Cancer Database was queried for skull base chordoma patients receiving definitive treatment. Facilities were categorized into 2 cohorts by calculating the mean number of patients treated per facility and using cutoff numbers that were 0.5 SD above and below the computed mean to separate the groups. As, by definition of the inclusion criteria, all included facilities treated at least 1 patient, low-volume facilities were defined as treating 1 patient, and high-volume facilities were defined as treating ≥7 patients; mid-volume facilities (facilities treating ≥2 but ≤6 patients) were excluded. Differences in treatment course, outcomes, and OS by facility type were assessed.

RESULTS

The study included 658 patients (44.8% female, 79.5% White). The 187 unique facilities were categorized into 95 low-volume facilities (treating 1 patient during timeline) and 26 high-volume facilities (treating ≥7 patients during timeline). Kaplan-Meier log-rank analysis demonstrated a significant positive association between facility volume and OS (P < 0.001) and an improvement in OS in patients at academic facilities (P = 0.018). On Cox proportional hazards multivariate regression after adjusting for sex, age, Charlson-Deyo comorbidity index, and insurance type, high-volume facilities and academic facilities were associated with a lower mortality risk than low-volume facilities and nonacademic facilities (P < 0.001 and P = 0.03, respectively).

CONCLUSIONS

Higher facility case volume and academic facility type appear to be associated with improved survival outcomes in treatment of skull base chordomas.

Evolution of Surgical Outcomes in Endoscopic Endonasal Resection of Craniopharyngiomas

Introduction Wide variations exist in the management of craniopharyngiomas, including pituitary stalk preservation/sacrifice. This study examines the practice patterns over 16 years using the endoscopic endonasal approach for the resection of craniopharyngiomas and it examines the effects of stalk preservation.

Methods Retrospective analysis was conducted for 66 patients who underwent endoscopic transsphenoidal surgery for resection of craniopharyngiomas. Patients were stratified into three epochs: 2005 to 2009 (N = 20), 2010 to 2015 (N = 23), and 2016 to 2020 (N = 20), to examine the evolution of surgical outcomes. Subgroup analysis between stalk preservation/stalk sacrifice was conducted for rate of gross total resection, anterior pituitary function preservation, and development of new permanent diabetes insipidus.

Results Gross total resection rates across the first, second, and third epochs were 20, 65, and 52%, respectively (p = 0.042). Stalk preservation across epochs were 100, 5.9, and 52.6% (p = 0.0001). New permanent diabetes insipidus did not significantly change across epochs (37.5, 68.4, 71.4%; p = 0.078). Preservation of normal endocrine function across epochs was 25, 0, and 23.8%; (p = 0.001). Postoperative cerebrospinal fluid (CSF) leaks significantly decreased over time (40, 4.5, and 0%; [p = 0.0001]). Stalk preservation group retained higher normal endocrine function (40.9 vs. 0%; p = 0.001) and less normal-preoperative to postoperative panhypopituitarism (18.4 vs. 56%; p = 0.001). Stalk sacrifice group achieved higher GTR (70.8 vs. 28%, p = 0.005). At last follow-up, there was no difference in recurrence/progression rates between the two groups.

Conclusion There is a continuous evolution in the management of craniopharyngiomas. Gross total resection, higher rates of pituitary stalk and hormonal preservation, and low rates of postoperative CSF leak can be achieved with increased surgical experience.

Endoscope-assisted resection of brainstem cavernous malformations

Targeted surgical precision and minimally invasive techniques are of utmost importance for resectioning cavernous malformations involving the brainstem region. Minimisation of the surgical corridor is desirable but should not compromise the extent of resection. This study provides detailed information on the role of endoscopy in this challenging surgical task. A retrospective analysis of medical documentation, radiologic studies and detailed intraoperative video documentation was performed for all consecutive patients who underwent surgical resection of brainstem cavernous malformations between 2010 and 2020 at the authors’ institution. A case-based volumetry of the corticotomy was performed and compared to cavernoma dimensions. A total of 20 procedures have been performed in 19 patients. Neuroendoscopy was implemented in all cases. The mean size of the lesion was 5.4 (± 5) mm3. The average size of the brainstem corticotomy was 4.5 × 3.7 (± 1.0 × 1.1) mm, with a median relation to the cavernoma’s dimension of 9.99% (1.2–31.39%). Endoscopic 360° inspection of the resection cavity was feasible in all cases. There were no endoscopy-related complications. Mean follow-up was 27.8 (12–89) months. Gross-total resection was achieved in all but one case (95%). Sixteen procedures (80%) resulted in an improved or stable medical condition. Eleven patients (61.1%) showed further improvement 12 months after the initial surgery. With the experience provided, endoscopic techniques can be safely implemented in surgery for BSCM. A combination of neuroendoscopic visualisation and neuronavigation might enable a targeted size of brainstem corticotomy. Endoscopy can currently be considered a valuable additive tool to facilitate the preparation and resection of BSCM.

Clinical Outcomes of Transcranial and Endoscopic Endonasal Surgery for Craniopharyngiomas: A Single-Institution Experience

Objective

Craniopharyngioma has always been a challenge for the neurosurgeon, and there is no consensus on optimal treatment. The objective of this study was to compare surgical outcomes and complications between transcranial surgery (TCS) and endoscopic endonasal surgery (EES) of craniopharyngiomas.

Methods

A retrospective review of patients who underwent craniopharyngioma resection at Wuhan Union Hospital between January 2010 and December 2019 was performed. A total of 273 patients were enrolled in this retrospective study. All patients were analyzed with surgical effects, endocrinologic outcomes, complications, and follow-up results.

Results

A total of 185 patients underwent TCS and 88 underwent EES. There were no significant differences in patient demographic data, preoperative symptoms, and tumor characteristics between the two groups. The mean follow-up was 30.5 months (range 8–51 months). The EES group had a greater gross total resection (GTR) rate (89.8% EES vs. 77.3% TCS, p < 0.05) and lower rate of hypopituitarism (53.4% EES vs. 68.1% TCS, p < 0.05) and diabetes insipidus (DI) (51.1% EES vs. 72.4% TCS, p < 0.05). More postoperative cerebrospinal fluid (CSF) leaks occurred in the EES group (4.5% EES vs. 0% TCS, p < 0.05). More patients in the EES group with preoperative visual deficits experienced improvement after surgery (74.5% EES vs. 56.3% TCS, p < 0.05). There were statistical differences in the recurrence rates (12.5% EES vs. 23.8% TCS, p < 0.05) between the 2 groups.

Conclusion

These data support the view that EES is a safe and effective minimally invasive surgery compared to TCS. Compared to TCS, EES has fewer surgical complications and a lower recurrence rate.

Surgical Management of Sinonasal Cancers: A Comprehensive Review

Surgery plays an important role in the treatment of sinonasal cancer. Many surgical approaches have been described, including open, endoscopic, or combined approaches. The choice is based on several criteria: general criteria related to the oncological results and morbidity of each technique, specific criteria related to the tumor (tumor extensions, tumor pathology), the patient, or the surgeon himself. The aims of this review are (i) to provide a complete overview of the surgical techniques available for the management of sinonasal malignant tumors, with a special focus on recent developments in the field of transnasal endoscopic surgery; (ii) to summarize the criteria that lead to the choice of one technique over another. In particular, the oncological outcomes, the morbidity of the different techniques, and the specificities of each histologic subtype will be discussed based on a comprehensive literature review.

Complications after 1002 endoscopic endonasal approach procedures at a single center: lessons learned, 2010-2018

OBJECTIVE

The endoscopic endonasal approach (EEA) has evolved into a mainstay of skull base surgery over the last two decades, but publications examining the intraoperative and perioperative complications of this technique remain scarce. A prior landmark series of 800 patients reported complications during the first era of EEA (1998-2007), parallel to the development of many now-routine techniques and technologies. The authors examined a single-institution series of more than 1000 consecutive EEA neurosurgical procedures performed since 2010, to elucidate the safety and risk factors associated with surgical and postoperative complications in this modern era.

METHODS

After obtaining institutional review board approval, the authors retrospectively reviewed intraoperative and postoperative complications and their outcomes in patients who underwent EEA between July 2010 and June 2018 at a single institution.

RESULTS

The authors identified 1002 EEA operations that met the inclusion criteria. Pituitary adenoma was the most common pathology (n = 392 [39%]), followed by meningioma (n = 109 [11%]). No patients died intraoperatively. Two (0.2%) patients had an intraoperative carotid artery injury: 1 had no neurological sequelae, and 1 had permanent hemiplegia. Sixty-one (6.1%) cases of postoperative cerebrospinal fluid leak occurred, of which 45 occurred during the original surgical hospitalization. Transient postoperative sodium dysregulation was noted after 87 (8.7%) operations. Six (0.6%) patients were treated for meningitis, and 1 (0.1%) patient died of a fungal skull base infection. Three (0.3%) patients died of medical complications, thereby yielding a perioperative 90-day mortality rate of 0.4% (4 deaths). High-grade (Clavien-Dindo grade III-V) complications were identified after 103 (10%) EEA procedures, and multivariate analysis was performed to determine the associations between factors and these more serious complications. Extradural EEA was significantly associated with decreased rates of these high-grade complications (OR [95% CI] 0.323 [0.153-0.698], p = 0.0039), whereas meningioma pathology (OR [95% CI] 2.39 [1.30-4.40], p = 0.0053), expanded-approach intradural surgery (OR [95% CI] 2.54 [1.46-4.42], p = 0.0009), and chordoma pathology (OR [95% CI] 9.31 [3.87-22.4], p < 0.0001) were independently associated with significantly increased rates of high-grade complications.

CONCLUSIONS

The authors have reported a large 1002-operation cohort of EEA procedures and associated complications. Modern EEA surgery for skull base pathologies has an acceptable safety profile with low morbidity and mortality rates. Nevertheless, significant intraoperative and postoperative complications were correlated with complex intradural procedures and meningioma and chordoma pathologies.

Risk factor for cerebrospinal fluid leak after endoscopic endonasal skull base surgery: a single-center experience

BACKGROUND

One of the major complications in endoscopic endonasal skull base surgery (EESBS) is postoperative cerebrospinal fluid (CSF) leaks. Recently, EESBS has been applied to various skull base diseases as well as more complicated cases influenced by previous treatment with or without various comorbidities.

AIMS/OBJECTIVES

This study aimed to assess the factors that influence the results of postoperative CSF leak after EESBS with mixed patient backgrounds.

MATERIALS AND METHODS

We conducted a retrospective analysis of the clinical records of patients undergoing EESBS in our institution from 2012 to 2017.

RESULTS

Out of a total of 230 cases of EESBS, 11 (4.8%) suffered from postoperative CSF leakage. The rate of CSF leakage for pituitary adenoma, Rathke's cleft cyst, chordoma, and meningioma was 3.5%, 0%, 3.6% and 8.0%, respectively. Multiple variate analysis revealed that repeated surgery (p = .008) and intraoperative CSF leak (p = .044) were significant risk factors for postoperative CSF leakage.

CONCLUSIONS AND SIGNIFICANCE

The rate of postoperative CSF leakage in this study was comparable to previous reports, and repeated surgery may increase postoperative CSF leakage. The surgical strategy for tumor removal as well as skull base reconstruction should be given careful consideration according to tumor pathology and the patient's condition.

Learning curve and technical nuances of endoscopic skull base reconstruction with nasoseptal flap to control high-flow cerebrospinal fluid leakage: reconstruction after endoscopic skull base surgery other than pituitary surgery

PURPOSE

Although reconstruction techniques after endoscopic skull base surgery have been improved, there are difficulties in reconstructing the skull base with a nasoseptal flap (NSF), especially in the case of high-flow cerebrospinal fluid (CSF) leak. The aim of this study was to analyze risk factors for the development of postoperative CSF leaks in terms of less experienced surgeon practices.

METHODS

Retrospective review of medical records was performed for 125 patients who underwent endoscopic skull base surgery for intradural pathology with intraoperative high-flow CSF leakage between Oct 2012 and Apr 2017. Basic demographic data were collected, including body mass index (BMI), tumor pathology, comorbidities, and outcomes. To assess the learning curve effect, patients were divided into early cohort (n = 30) and late cohort (n = 95) groups.

RESULTS

Overall postoperative CSF leakage was 10.4% (13/125) in this series. There were no significant risk factors for postoperative CSF leakage among the demographic data including BMI, comorbidities, or radiation history. Postoperative CSF leakage was most prevalent in the transclival approach than in other approaches, but the difference was not statistically significant (20.8%, p = 0.351). When dividing the results by timetable, the patients who underwent skull base reconstruction in the early cohort experienced more postoperative CSF leakage (23.3%, 7 cases out of 30) than in the late cohort (6.3%, 6 cases out of 95, p = 0.014). The learning curve was steeper in the early cohort (30 early cases 23.3%, 31-60 10%, 61-90 6.7%, 91-125 2.9%).

CONCLUSIONS

To improve the success rate of endoscopic skull base reconstruction, surgeons have to keep the basic technical details in mind to reduce the learning curve.

Creative and Innovative Methods and Techniques for the Challenges in the Management of Adult Craniopharyngioma

Craniopharyngioma remains a major challenge in daily clinical practice. The pathobiology of the tumor is still elusive, and there are no consensus or treatment guidelines on the optimal management strategy for this relatively rare tumor. However, recent technical and scientific advances, including genomic and radiomic profiling, innovation in surgical approaches, more precise radiotherapy protocols, targeted therapy, and restoration of lost functions all have the potential to significantly improve the outcome of patients with craniopharyngioma in the near future. Although many of these innovative tools in the new armamentarium of the clinician are still in their infancy, they could reduce craniopharyngioma-related morbidity and mortality and improve the patients' quality of life. In this article, we discuss these creative and innovative approaches that may offer solutions to the obstacles faced in treating craniopharyngioma and future possibilities in improving the care of these patients.

Cerebrospinal fluid leakage repair of various grades developing during endoscopic transnasal transsphenoidal surgery

Objectives

We describe the strategy used to repair intraoperative leaks of various grades and define factors for preventing postoperative cerebrospinal fluid leakage (CSF) after surgery via the endoscopic endonasal transsphenoidal approach (EETA).

Study design

Retrospective chart review at a tertiary referral center.

Methods

Patients who underwent surgery via EETA from January 2009 to May 2020 were retrospectively reviewed. Intraoperative CSF leakage was graded 0–3 in terms of the dural defect size; various repairs were used depending on the grade.

Results

A total of 777 patients underwent 869 operations via EETA; 609 (70.1%) experienced no intraoperative CSF leakage (grade 0) but 260 (29.9%) did. Leakage was of grade 1 in 135 cases (15.5%), grade 2 in 83 (9.6%), and grade 3 in 42 (4.8%). In 260 patients with intraoperative CSF leakage, a buttress was wedged into the sellar defect site in 178 cases (68.5%) and a pedicled flap was placed in 105 cases (40.4%). Autologous fat (108 cases, 41.5%) and a synthetic dural substitute (91 cases, 35%) were used to fill the dead space of the sellar resection cavity. Postoperative CSF leakage developed in 21 patients: 6 of grade 1, 7 of grade 2, and 8 of grade 3. Buttress placement significantly decreased postoperative leakage in grade 1 patients (p = 0.041). In patients of perioperative leakage grades 2 and 3, postoperative CSF leakage was significantly reduced only when both fat and a buttress were applied (p = 0.042 and p = 0.043, respectively).

Conclusion

A buttress prevented postoperative CSF leakage in grade 1 patients; both fat and buttress were required by patients with intraoperative leakage of grades 2 and 3.

Reconstruction after extended endonasal approaches to the anterior cranial base: surgical techniques and current results

The development of extended endoscopic endonasal approaches (EEA) to the anterior skull base has allowed successful resection of selected extradural and intradural skull base tumors through an endonasal corridor, minimizing brain and cranial nerve manipulation. However, as the complexity of the approaches has increased, so has the need for more robust and reliable reconstructive options to minimize morbidity. Reconstructive decision-making after extended EEA for anterior skull base tumors must take into consideration multiple factors including patient characteristics (Body Mass Index, previous surgeries, and radiation), location and the size of the skull base defect. A multilayered reconstruction which includes a combination of free grafts and a vascularized flap is the standard approach to anterior skull base defects after EEA and should be applied in a stepwise manner tailored to each patient. The techniques and materials used to accomplish skull base repair are discussed, the outcomes in the literature are reviewed, and our reconstructive paradigm presented.

Surgical anatomy and technical nuances of the endoscopic endonasal approach to the anterior cranial fossa

Endoscopic endonasal approaches (EEA) to the skull base have significantly impacted the management of lesions located in the cranial base. Specifically, lesions arising from the anterior cranial fossa, such as pituitary macroadenomas, craniopharyngiomas meningiomas and craniofacial malignancies have benefited from the development of such approaches. Understanding of the anatomy of the anterior fossa is of utmost importance for the successful selection of the approach and application of surgical techniques in EEA. In the current manuscript, we review the most relevant points of surgical anatomy and nuances of the surgical technique of EEA to the anterior fossa. Anatomical landmarks for the transtuberculum transplanum and transcribriform approaches are discussed and a step-by-step description for those approaches is presented. We reinforce that safe and effective application of such techniques follow the same principles of other skull base surgery techniques: mastering of surgical anatomy, adequate case selection, correct instrumentation and surgical experience.

Anatomic Nuances of the Ophthalmic Artery Origin from a Ventral Viewpoint: Considerations and Implications for Endoscopic Endonasal Surgery

BACKGROUND

The origin of the ophthalmic artery is within the surgical field of endoscopic endonasal approaches (EEAs) to the suprasellar and parasellar regions. However, its anatomy from the endoscopic point-of-view has not been adequately elucidated.

OBJECTIVE

To highlight the anatomy of the ophthalmic artery origin from an endoscopic endonasal perspective.

METHODS

The origin of the ophthalmic artery was studied bilaterally under endoscopic visualization, after performing transplanum/transtubercular EEAs in 17 cadaveric specimens (34 arteries). Anatomic relationships relevant to surgery were evaluated. To complement the cadaveric findings, the ophthalmic artery origin was reviewed in 200 "normal" angiographic studies.

RESULTS

On the right side, 70.6% of ophthalmic arteries emerged from the superior aspect, while 17.6% and 11.8% emerged from the superomedial and superolateral aspects of the intradural internal carotid artery, respectively. On the left, 76.5%, 17.6%, and 5.9% of ophthalmic arteries emerged from the superior, superomedial, and superolateral aspects of the internal carotid, respectively. Similar findings were observed on angiography. All ophthalmic arteries emerged at the level of the medial opticocarotid recess. Overall, 47%, 26.5%, and 26.5% of ophthalmic arteries (right and left) were inferolateral, inferior, and inferomedial to the intracranial optic nerve segment, respectively. On both sides, the intracranial length of the ophthalmic artery ranged from 1.5 to 4.5 mm (mean: 2.90 ± standard deviation of 0.74 mm).

CONCLUSION

Awareness of the endoscopic nuances of the ophthalmic artery origin is paramount to minimize the risk of sight-threatening neurovascular injury during EEAs to the suprasellar and parasellar regions.

Reconstruction of pediatric skull base defects: A retrospective analysis emphasizing the very young

INTRODUCTION

Pathology of the pediatric skull base is rare and ranges from congenital defects to malignancy and traumatic defects. Pediatric patients, particularly those ≤6 years of age, present a unique set of anatomic challenges for the skull base surgeon. The goal of this study was to retrospectively review our experience with reconstruction of pediatric skull base defects with particular emphasis on those ≤6 years of age.

METHODS

A retrospective chart review was conducted of patients ≤20 years of age who underwent endoscopic endonasal and combined endoscopic and open approaches to address cranial base pathology from 2007 to 2018. Patients were divided into two groups; those ≤6 years of age (group A) and those >6 years of age and ≤20 years of age (group B) and reconstructive techniques and outcomes were analyzed.

RESULTS

Intraoperative communication with the subarachnoid space (CSF leak) was created in 50% (3/6) of patients ≤ 6 years of age compared to 32.7% (16/49) in patients > 6 years and ≤20 years of age (P < 0.40) in management of their skull base disease. A vascularized flap was utilized for reconstruction in 66.7% (4/6) of patients ≤ 6 years of age and included a nasoseptal flap in 33.3% (2/6). A vascularized flap was utilized for reconstruction in 38.8% (19/49) of patients > 6 years and ≤20 years of age and most commonly included a nasoseptal flap (22.4%, 11/49). A lumbar drain was utilized in 50% (3/6) of patients ≤ 6 years of age compared to 18.4% (9/49) in patients > 6 and ≤20 years of age (P < 0.08). Post-operative CSF leaks were encountered in 16.7% (1/6) of patients ≤ 6 years of age compared to 10.2% (5/49) in patients > 6 and ≤20 years of age (P < 0.63). Behavioral issues were noted to potentially contribute to failed skull base reconstruction in patients <6 years of age.

CONCLUSIONS

Pediatric patients, particularly those ≤6 years of age, present a unique set of anatomic and behavioral challenges for the skull base surgeon as highlighted in this study.

ICAR: endoscopic skull-base surgery

BACKGROUND

Endoscopic skull-base surgery (ESBS) is employed in the management of diverse skull-base pathologies. Paralleling the increased utilization of ESBS, the literature in this field has expanded rapidly. However, the rarity of these diseases, the inherent challenges of surgical studies, and the continued learning curve in ESBS have resulted in significant variability in the quality of the literature. To consolidate and critically appraise the available literature, experts in skull-base surgery have produced the International Consensus Statement on Endoscopic Skull-Base Surgery (ICAR:ESBS).

METHODS

Using previously described methodology, topics spanning the breadth of ESBS were identified and assigned a literature review, evidence-based review or evidence-based review with recommendations format. Subsequently, each topic was written and then reviewed by skull-base surgeons in both neurosurgery and otolaryngology. Following this iterative review process, the ICAR:ESBS document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:ESBS document addresses the role of ESBS in primary cerebrospinal fluid (CSF) rhinorrhea, intradural tumors, benign skull-base and orbital pathology, sinonasal malignancies, and clival lesions. Additionally, specific challenges in ESBS including endoscopic reconstruction and complication management were evaluated.

CONCLUSION

A critical review of the literature in ESBS demonstrates at least the equivalency of ESBS with alternative approaches in pathologies such as CSF rhinorrhea and pituitary adenoma as well as improved reconstructive techniques in reducing CSF leaks. Evidence-based recommendations are limited in other pathologies and these significant knowledge gaps call upon the skull-base community to embrace these opportunities and collaboratively address these shortcomings.

The expanded endonasal approach in pediatric skull base surgery: A review

OBJECTIVE

Surgery of the pediatric skull base has multiple unique challenges and has seen recent rapid advances. The objective of this review is to assess key issues in pediatric skull base surgery (SBS), including anatomic limitations, surgical approaches, reconstruction techniques, postoperative care, complications, and outcomes.

DATA SOURCES

PubMed literature review.

REVIEW METHODS

A review of the literature was conducted to assess the challenges, recent advances, and reported outcomes in pediatric SBS.

RESULTS

The pediatric skull base presents multiple anatomic challenges, including variable patterns of pneumatization, narrow piriform aperture width, and narrow intercarotid distance at the level of the cavernous sinus but not the superior clivus. These issues may be particularly challenging in patients less than 2 years of age. Endoscopic endonasal approaches in the sagittal and coronal plane have been applied to the pediatric skull base while open approaches may still be necessary in the setting of extensive intracranial or orbital disease, as well as disease lateral to critical neurovascular structures. While the nasoseptal flap was initially called into question for pediatric cases, it has been shown through multiple reports to be a feasible and robust reconstructive option. Complications and outcomes often depend upon the pathology. In children, response to noxious stimuli, ability to avoid Valsalva, and adherence to nasal precautions is variable. The use of lumbar drains is more common in pediatric than adult patients.

CONCLUSION

While the pediatric skull base presents unique challenges, outcomes data support that endoscopic endonasal approaches are a pertinent surgical technique in appropriately selected patients.

LEVEL OF EVIDENCE

3a.

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.

The endoscopic endonasal approach for pediatric craniopharyngiomas: the key lessons learned

PURPOSE

The aim of this study is to highlight the role of the endoscopic endonasal approach (EEA) in pediatric craniopharyngiomas by reviewing our experience and the key lessons learned from the application of this approach in children.

METHODS

Between 1998 and 2017, 12 pediatric craniopharyngiomas were treated via EEA at our institution. Demographic data, preoperative assessment, tumor features, surgical results, complications, and recurrences were analyzed.

RESULTS

Visual defects were the most frequent presenting sign. Seven craniopharyngiomas were infradiaphragmatic, and five were supradiaphragmatic. The EEA was successfully performed in all cases with no complication related to children's sinonasal anatomy. Gross total resection (GTR) rate was of 75%. Endocrinological disturbances improved in one case (20%) and worsened in three (60%). New onset of diabetes insipidus was observed in four (36%) children. Visual defect improved in 91% of cases, with no new postoperative deficit. Postoperative cerebrospinal fluid (CSF) leak occurred in one patient (8%). Three patients (27%) experienced tumor regrowth, and one craniopharyngioma recurred (mean follow-up, 78 months).

CONCLUSIONS

The EEA offers a straight route to the sellar-suprasellar, making it the ideal approach for pediatric infradiaphragmatic craniopharyngiomas. In supradiaphragmatic craniopharyngiomas, the extended EEA provides a clearer and close-up visualization of the tumor-hypothalamus interface, which can grant better results in terms of quality of life. The pediatric skull base anatomy should not represent a contraindication for the endoscopic technique. Larger series encompassing a wider spectrum of pediatric craniopharyngiomas are needed to further support the benefits of this surgical approach.

Pediatric craniopharyngioma

BACKGROUND

Craniopharyngioma has historically been recognized to be a formidable pathology primarily due to its proximity to critical neurovascular structures and the challenging surgical corridors that surgeons have tried to reach this lesion.

FOCUS OF REVIEW

In this work, we review the medical and surgical management of these tumors with a focus on clinical presentation, diagnostic identification, surgical approach, and associated adjuvant therapies. We will also discuss our current treatment paradigm using endoscopic, open, and combined approaches to craniopharyngiomas. The management of craniopharyngiomas requires a multidisciplinary team of surgeons, endocrinologists, and neuroanesthesiologists as well as neurocritical care specialists to deliver the most comprehensive and safest surgical resection with minimal postoperative morbidity.

Proposal of Standardization of Closure Techniques After Endoscopic Pituitary and Skull Base Surgery Based on Postoperative Cerebrospinal Fluid Leak Risk Classification

Postoperative cerebrospinal fluid (CSF) leak still represents the main limitation of endonasal endoscopic surgery. The aim of the study is to classify the risk of postoperative leak and to propose a decision-making protocol to be applied in the preoperative phase based on radiological data and on intraoperative findings to obtain the best closure.One hundred fifty-two patients were treated in our institution; these patients were divided into 2 groups because from January 2013 the closure technique was standardized adopting a preoperative decision-making protocol. The Postoperative CSF leak Risk Classification (PCRC) was estimated taking into account the size of the lesion, the extent of the osteodural defect, and the presence of intraoperative CSF leak (iCSF-L). The closure techniques were classified into 3 types according to PCRC estimation (A, B, and C).The incidence of the use of a nasoseptal flap is significantly increased in the second group 80.3% versus 19.8% of the first group and the difference was statistically significant P < 0.0001. The incidence of postoperative CSF leak (pCSF-L) in the first group was 9.3%. The incidence of postoperative pCSF-L in the second group was 1.5%. An analysis of the pCSF-L rate in the 2 groups showed a statistically significant difference P = 0.04.The type of closure programmed was effective in almost all patients, allowing to avoid the possibility of a CSF leak. Our protocol showed a significant total reduction in the incidence of CSF leak, but especially in that subgroup of patients where a leak is usually unexpected.

Preservation of Hypothalamic Function with Endoscopic Endonasal Resection of Hypothalamus-Invaded Craniopharyngiomas

OBJECTIVE

To analyze the preservation of hypothalamic function using the endoscopic endonasal approach (EEA) in a single-center clinical series of patients with hypothalamus-invaded craniopharyngioma (CP) and compare this series with reported cases by the open transcranial approach (TCA).

METHODS

A retrospective review of hypothalamus-invaded CP surgical cases treated with EEA was performed. Hypothalamic damage was evaluated in terms of the body mass index (BMI), endocrine status, and quality of life before and after surgery. A review of the available literature reporting the use of EEA and TCA over the last decade was performed for comparison.

RESULTS

In total, 63 cases amenable to EEA were investigated. The elevation in BMI was substantial and an increase in BMI greater than 9% was observed in 22 patients (34.92%). Most patients exhibited a BMI gain >9% within 3 months postoperatively. A total of 16 of the 19 patients who had normal anterior pituitary function preoperatively worsened after surgery. Of the 27 cases reporting preoperative partial hypopituitarism, 16 cases worsened postoperatively and 11 cases remained unchanged. All 9 cases with preoperative panhypopituitarism remained unchanged postoperatively. A total of 40 new cases developed diabetes insipidus, and 3 of the 10 patients with preoperative diabetes insipidus exhibited resolved at the latest follow-up. The quality of life showed no significant difference.

CONCLUSIONS

EEA can achieve greater gross total resection than TCA when performed by an experienced surgeon. Combined with the reduced postoperative hypothalamic damage in our patients with only hypothalamus-invaded CP, especially the shortened time horizons of hypothalamic obesity development and reduced percentage of patients with obesity, the EEA technique should be a preferred alternative over TCA.

Beyond the Learning Curve: Comparison of Microscopic and Endoscopic Incidences of Internal Carotid Injury in a Series of Highly Experienced Operators

BACKGROUND

As the endoscopic endonasal approach (EEA) has gained popularity as an alternative to microsurgery (MS) for transsphenoidal resection (TSR), numerous studies have attempted to assess the differential risk of internal carotid artery (ICA) injury between the techniques, yet results have been equivocal and contradictory. The aim of this study was to evaluate ICA injury in MS versus EEA among highly experienced neurosurgeons.

METHODS

We performed a systematic literature review of publications from 2002-2017 reporting ICA injury outcomes in ≥250 cases using MS or EEA.

RESULTS

Seventeen series reporting 11,149 patients were included: 3 MS series, 13 EEA series, and 1 series with adequate samples for each. ICA injury incidences were 0.0%-1.6% in cohorts of 275-3000. MS series documented 5 ICA injuries in 2672 operations, for an overall incidence of 0.2% (range, 0.0%-0.4%), and EEA series reported 30 ICA injuries in 8477 operations, for a 0.4% injury rate (range, 0.0%-1.6%); the difference was nonsignificant (P = 0.25). Increased operative experience was associated with decreased incidence of ICA injury, a finding preserved in the overall study cohort and within discretely examined MS and EEA subgroups (overall r² = 0.08, MS r² = 0.23, EEA r² = 0.07).

CONCLUSIONS

ICA injury is the most serious complication of TSR of pituitary neoplasms. Operator inexperience may be a more important risk factor than choice of surgical technique, given the comparably low rates of injury obtained by highly experienced surgeons independent of technique. This emphasizes the need for consolidated care in pituitary centers of excellence, improvement of high-fidelity simulators, and skull base mentorship between senior and junior staff.

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

Objective

The authors previously described a graded approach to skull base repair following endonasal microscopic or endoscope-assisted tumor surgery. In this paper they review their experience with skull base reconstruction in the endoscopic era.

Methods

A retrospective review of a single-institution endonasal endoscopic patient database (April 2010–April 2017) was undertaken. Intraoperative CSF leaks were graded based on size (grade 0 [no leak], 1, 2, or 3), and repair technique was documented across grades. The series was divided into 2 epochs based on implementation of a strict perioperative antibiotic protocol and more liberal use of permanent and/or temporary buttresses; repair failure rates and postoperative meningitis rates were assessed for the 2 epochs and compared.

Results

In total, 551 operations were performed in 509 patients for parasellar pathology, including pituitary adenoma (66%), Rathke’s cleft cyst (7%), meningioma (6%), craniopharyngioma (4%), and other (17%). Extended approaches were used in 41% of cases. There were 9 postoperative CSF leaks (1.6%) and 6 cases of meningitis (1.1%). Postoperative leak rates for all 551 operations by grade 0, 1, 2, and 3 were 0%, 1.9%, 3.1%, and 4.8%, respectively. Fat grafts were used in 33%, 84%, 97%, and 100% of grade 0, 1, 2, and 3 leaks, respectively. Pedicled mucosal flaps (78 total) were used in 2.6% of grade 0–2 leaks (combined) and 79.5% of grade 3 leaks (60 nasoseptal and 6 middle turbinate flaps). Nasoseptal flap usage was highest for craniopharyngioma operations (80%) and lowest for pituitary adenoma operations (2%). Two (3%) nasoseptal flaps failed. Contributing factors for the 9 repair failures were BMI ≥ 30 (7/9), lack of buttress (4/9), grade 3 leak (4/9), and postoperative vomiting (4/9). Comparison of the epochs showed that grade 1–3 repair failures decreased from 6/143 (4.1%) to 3/141 (2.1%) and grade 1–3 meningitis rates decreased from 5 (3.5%) to 1 (0.7%) (p = 0.08). Prophylactic lumbar CSF drainage was used in only 4 cases (< 1%), was associated with a higher meningitis rate in grades 1–3 (25% vs 2%), and was discontinued in 2012. Comparison of the 2 epochs showed increase buttress use in the second, with use of a permanent buttress in grade 1 and 3 leaks increasing from 13% to 55% and 32% to 76%, respectively (p < 0.001), and use of autologous septal/keel bone as a permanent buttress in grade 1, 2, and 3 leaks increasing from 15% to 51% (p < 0.001).

Conclusions

A graded approach to skull base repair after endonasal surgery remains valid in the endoscopic era. However, the technique has evolved significantly, with further reduction of postoperative CSF leak rates. These data suggest that buttresses are beneficial for repair of most grade 1 and 2 leaks and all grade 3 leaks. Similarly, pedicled flaps appear advantageous for grade 3 leaks, while CSF diversion may be unnecessary and a risk factor for meningitis. High BMI should prompt an aggressive multilayered repair strategy. Achieving repair failure and meningitis rates lower than 1% is a reasonable goal in endoscopic skull base tumor surgery.

Defining the lateral limits of the endoscopic endonasal transtuberculum transplanum approach: anatomical study with pertinent quantitative analysis

OBJECTIVE

The extended endoscopic endonasal transtuberculum transplanum approach is currently used for the surgical treatment of selected midline anterior skull base lesions. Nevertheless, the possibility of accessing the lateral aspects of the planum sphenoidale could represent a limitation for such an approach. To the authors' knowledge, a clear definition of the eventual anatomical boundaries has not been delineated. Hence, the present study aimed to detail and quantify the maximum amount of bone removal over the planum sphenoidale required via the endonasal pathway to achieve the most lateral extension of such a corridor and to evaluate the relative surgical freedom.

METHODS

Six human cadaveric heads were dissected at the Laboratory of Surgical NeuroAnatomy of the University of Barcelona. The laboratory rehearsals were run as follows: 1) preliminary predissection CT scans, 2) the endoscopic endonasal transtuberculum transplanum approach (lateral limit: medial optocarotid recess) followed by postdissection CT scans, 3) maximum lateral extension of the transtuberculum transplanum approach followed by postdissection CT scans, and 4) bone removal and surgical freedom analysis (a nonpaired Student t-test). A conventional subfrontal bilateral approach was used to evaluate, from above, the bone removal from the planum sphenoidale and the lateral limit of the endonasal route.

RESULTS

The endoscopic endonasal transtuberculum transplanum approach was extended at its maximum lateral aspect in the lateral portion of the anterior skull base, removing the bone above the optic prominence, that is, the medial portion of the lesser sphenoid wing, including the anterior clinoid process. As expected, a greater bone removal volume was obtained compared with the approach when bone removal is limited to the medial optocarotid recess (average 533.45 vs 296.07 mm2; p < 0.01). The anteroposterior diameter was an average of 8.1 vs 15.78 mm, and the laterolateral diameter was an average of 18.77 vs 44.54 mm (p < 0.01). The neurovascular contents of this area were exposed up to the insular segment of the middle cerebral artery. The surgical freedom analysis revealed a possible increased lateral maneuverability of instruments inserted in the contralateral nostril compared with a midline target (average 384.11 vs 235.31 mm2; p < 0.05).

CONCLUSIONS

Bone removal from the medial aspect of the lesser sphenoid wing, including the anterior clinoid process, may increase the exposure and surgical freedom of the extended endoscopic endonasal transtuberculum transplanum approach over the lateral segment of the anterior skull base. Although this study represents a preliminary anatomical investigation, it could be useful to refine the indications and limitations of the endoscopic endonasal corridor for the surgical management of skull base lesions involving the lateral portion of the planum sphenoidale.

Pediatric Craniopharyngiomas: A Primer for the Skull Base Surgeon

Pediatric craniopharyngioma is a rare sellar-region epithelial tumor that, in spite of its typically benign pathology, has the potential to be clinically devastating, and presents a host of formidable management challenges for the skull base surgeon. Strategies in craniopharyngioma care have been the cause of considerable controversy, with respect to both philosophical and technical issues. Key questions remain unresolved, and include optimizing extent-of-resection goals; the ideal radiation modality and its role as an alternative, adjuvant, or salvage treatment; appropriate indications for expanded endoscopic endonasal surgery as an alternative to transcranial microsurgery; risks and benefits of skull base techniques in a pediatric population; benefits of and indications for intracavitary therapies; and the preferred management of common treatment complications. Correspondingly, we sought to review the preceding basic science and clinical outcomes literature on pediatric craniopharyngioma, so as to synthesize overarching recommendations, highlight major points of evidence and their conflicts, and assemble a general algorithm for skull base surgeons to use in tailoring treatment plans to the individual patient, tumor, and clinical course. In general terms, we concluded that safe, maximal, hypothalamic-sparing resection provides very good tumor control while minimizing severe deficits. Endoscopic endonasal, intraventricular, and transcranial skull base technique all have clear roles in the armamentarium, alongside standard craniotomies; these roles frequently overlap, and may be further optimized by using the approaches in adaptive combinations. Where aggressive subtotal resection is achieved, patients should be closely followed, with radiation initiated at the time of progression or recurrence-ideally via proton beam therapy, although three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, and stereotactic radiosurgery are very appropriate in a range of circumstances, governed by access, patient age, disease architecture, and character of the recurrence. Perhaps most importantly, outcomes appear to be optimized by consolidated, multidisciplinary care. As such, we recommend treatment in highly experienced centers wherever possible, and emphasize the importance of longitudinal follow-up-particularly given the high incidence of recurrences and complications in a benign disease that effects a young patient population at risk of severe morbidity from hypothalamic or pituitary injury in childhood.

The learning curve for endoscopic trans-sphenoidal resection of pituitary macroadenomas. A single institution experience, Leeds, UK

BACKGROUND

The object of this study was to assess whether increasing operative experience results in greater endoscopic trans-sphenoidal resection of pituitary macroadenomas and lower complications.

METHODS

A retrospective single institution cohort study was performed. Subjects underwent endoscopic trans-sphenoidal resection of pituitary macroadenoma between July 2009 and July 2016 by three neurosurgeons. Following data collection, statistical analysis compared percentage of tumor resection and length of hospital stay (LOS) with experience. Complications including CSF leak are reported.

RESULTS

In total, 142 patients (87 male, 55 female) mean age 55.1 were included. Surgeon 1 performed 106 cases; surgeon 2 performed 23 cases; and surgeon 3 performed 13 cases. Mean pre-operative tumor volumes were 8.18 cm³, 6.52 cm³, and 3.47 cm³ and post-operative volumes were 2.21, 1.74, and 1.93 cm³ for surgeons 1, 2, and 3, respectively. Respective percentage resections were 74.3, 77.2, and 52.1%. Analysis demonstrated no difference in tumor resection with increasing experience for all three surgeons (p = 0.11, p = 0.17, and p = 0.26). Tumor consistency and cavernous sinus involvement did not appear to affect tumor resection. Mean LOS was 5 days, 4 days, and 3 days, respectively, with no significant correlation with experience for all three surgeons. Intraoperative CSF leak incidence was 19/106 (18%) for surgeon 1, 6/23(26%) for surgeon 2, and 2/13(15%) for surgeon 3. Primary closure rate was 96.3% and only three other complications occurred.

CONCLUSIONS

This study demonstrates that in our institution there is no statistically significant learning curve for the endoscopic resection of pituitary macroadenoma. However, there is a trend of improvement in tumor resection with experience for one surgeon. These findings suggest that the surgeons in our institution were capable of performing this procedure effectively with a low complication rate since adoption of the endoscopic technique in 2009.