Safety and efficacy of hydroset cranioplasty as an adjunct to gasket-seal and nasoseptal flap closure of the skull base. A case-controlled study.

BACKGROUND: Cerebrospinal fluid leak after endoscopic skull base surgery remains a significant complication. Several investigators have suggested Hydroset cranioplasty to reduce leak rates. We investigated our early experience with Hydroset and compared the rate of nasal complications and CSF leak rates with case-controlled historic controls. METHODS: We queried a prospective database of patients undergoing first time endoscopic, endonasal resection of suprasellar meningiomas and craniopharyngiomas from 2015 to 2023. We compared cases closed with a gasket seal, Hydroset, and a nasoseptal flap with those closed with only a gasket seal and nasoseptal flap. Demographics, technical considerations and postoperative outcomes (SNOT-22) were compared. RESULTS: Seventy patients met inclusion criteria, twenty patients in the Hydroset group (meningioma n = 12; craniopharyngioma n = 8) and 50 control patients (meningioma n = 25; craniopharyngioma n = 25). CSF diversion was used in fewer Hydroset patients (75%, 15/20) compared with control group (94%, 47/50; p = 0.02). CSF leak was less frequent in the Hydroset than the control group (5% versus 12%, p = 0.38). One Hydroset patient required delayed nasal debridement. SNOT-22 responses demonstrated no significant difference in sinonasal complaints between groups (Hydroset average SNOT-22 score 22.45, control average SNOT-22 score 25.90; p = 0.58). CONCLUSIONS: We demonstrate that hydroxyapatite reconstruction leads to improved CSF leak control above that provided by the gasket-seal and nasoseptal flap, without significant associated morbidity as long as the cement is fully covered with vascularized tissue.

Durable headache relief following endoscopic endonasal resection of sub-centimeter Rathke cleft cysts in medically refractory patients.

BACKGROUND: The most common presenting symptom in patients with both small and large Rathke cleft cysts (RCC) is headache (H/A). It is well established that patients with large RCC can have significant symptomatic improvement after cyst drainage. However, patients with small RCC (≤ 1 cm) are rarely operated on, even if they present with debilitating H/A. It is not well understood whether resection of these smaller RCCs can lead to durable H/A resolution. METHODS: A retrospective search of our institutional database for sub-centimeter RCCs presenting with intractable H/A and treated with an endoscopic endonasal approach was carried out. A detailed H/A questionnaire as well as patient chart review was conducted to assess the long-term outcome of these patients after surgical intervention. RESULTS: Ten consecutive patients with 11 endonasal surgeries met inclusion criteria. Eight responded to the questionnaire. The median cyst diameter was 6 mm (IQR 3-9). Median preoperative H/A duration was 12 months (range 2 months-15 years). H/As occurred on average for 20 days per month and all required analgesics for symptomatic control for more than 15 of these 20 days. Half of the patients also had to miss work because of H/A. Average preoperative H/A intensity was 8.7 (scale 0-10) compared with postoperative scores of 2.9 at one month, 1.6 at 3 months, and 0.9 at 1 year. There were no permanent endocrinological or other surgical complications. After a median follow-up of 2 years, one patient had radiographic and symptomatic recurrence which resolved after re-operation. CONCLUSIONS: Endoscopic fenestration of sub-centimeter RCCs provides a safe and durable treatment for patients with intractable H/A.

Low incidence of true Sternberg's canal defects among lateral sphenoid sinus encephaloceles.

BACKGROUND: Spontaneous sphenoid sinus cerebrospinal fluid (CSF) encephaloceles have been postulated to arise from a persistent Sternberg's canal. However, recent evidence has questioned this embryological etiology. We examined the anatomic location of a series of lateral sphenoid sinus encephaloceles to determine if they corresponded with the location of Sternberg's canal. METHODS: We queried a prospectively acquired database of surgically treated spontaneous CSF leaks and identified those arising from the sphenoidal sinus. Images were reviewed to characterize the leaks with respect to the foramen rotundum (FR) and the vidian canal (VC). Four leak types were classified of which Type I (medial to FR and VC entering nasopharynx) was theoretically located in the precise location of Sternberg's canal. Type II was medial to FR; Type III was lateral to FR; Type IV passed through an enlarged FR into sphenoid sinus. Demographic data were analyzed. RESULTS: Of 103 repaired CSF leaks, 17 arose from the lateral sphenoid sinus. There were no true Type I leaks, 3 Type II leaks, 12 Type III leaks, and 2 Type IV leaks. No differences were found with respect to sphenoid pneumatization, BMI, age, sex, arachnoid pits, or postoperative leak between different types. CONCLUSIONS: No evidence was found to support the existence of a classic Sternberg canal CSF leak, supporting the hypothesis that most sphenoid spontaneous leaks likely occur secondary to chronically elevated ICP. Rare cases may be related to a weakness in the sphenoid wall in the region of Sternberg's canal.

Acellular dermal matrix as an alternative to autologous fascia lata for skull base repair following extended endoscopic endonasal approaches.

BACKGROUND: Skull base reconstruction after extended endoscopic endonasal approaches (EEAs) can be challenging. In addition to the nasoseptal flap, which has been adopted by most centers, autologous fascia lata is also often utilized. Harvesting of fascia lata requires a separate thigh incision, may prolong recovery, and results in a visible scar. In principal, the use of non-autologous materials would be preferable to avoid a second incision and maintain the minimally invasive nature of the approach, assuming the CSF leak rate is not compromised. OBJECTIVE: To assess the efficacy of acellular dermal matrix (ADM) as a non-autologous alternative to autologous fascia lata graft for watertight closure of the cranial base following EEAs. METHODS: A retrospective chart review of extended EEAs performed before and after the transition from fascia lata to ADM was performed. Cases were frequency matched for approach, pathology, BMI, use of lumbar drainage, and tumor volume. Power analysis was performed to estimate the sample size needed to demonstrate non-inferiority. RESULTS: ADM was used for watertight closure of the cranial base in 19 consecutive extended endoscopic endonasal approaches (16 gasket-seals and 3 buttons) with 1 postoperative CSF leak at the last follow-up (median 5.3, range 1.0-12.6 months). All patients had high-flow intraoperative leaks. The cohort included 8 meningiomas, 8 craniopharyngiomas, 2 chordomas, and 1 pituicytoma ranging in size from 0.2 to 37.2cm3 (median 5.5, IQR 2.8-13.3 cm3). In 19 historical controls who received fascia lata, there were 2 postoperative CSF leaks. CONCLUSIONS: Preliminary results suggest that ADM provides a non-inferior non-autologous alternative to fascia lata for watertight gasket-seal and button closures following extended EEAs, potentially reducing or eliminating the need to harvest autologous tissue.

The slope of the learning curve in 600 consecutive endoscopic transsphenoidal pituitary surgeries.

BACKGROUND: Endonasal endoscopic transsphenoidal surgery (EETS) for pituitary adenoma has become a mainstay of treatment over the last two decades and it is generally accepted that once this learning curve is achieved, a plateau is reached with little incremental improvement. OBJECTIVE: The objective of this study was to assess the slope of the learning curve over a long period of time for a variety of outcomes measures. METHODS: We examined outcomes and complications in a consecutive series of 600 EETS for pituitary adenoma grouped into quartiles based on date of surgery. RESULTS: GTR significantly increased across quartiles from 55 to 79% in the last quartile (p < 0.005). The rate of intraoperative CSF leak significantly decreased from 60% in the first quartile to 33% in the last quartile and the rate of lumbar drain placement from 28% in the first quartile to 6% in the last quartile (p < 0.005). Hormonal remission for secreting adenomas increased from 68% in the first quartile to 90% in the last quartile (p < 0.05). The rate of post-operative CSF leak trended lower (3% in first quartile to 0.7% in last two quartiles). The greatest improvement in outcome occurred between the first and second quartiles (19.9%), but persistent improvement occurred between the second and third (6.7%) and third and fourth quartiles (8.0%). CONCLUSION: Although the slope of the learning curve is steeper earlier in a surgeon's experience, the slope does not plateau and continues to increase even over more than a decade.

Increased frequency of cataract surgery in patients over age 50 with pituitary macroadenomas and chiasmal compression.

BACKGROUND: Patients with visual loss from macroadenomas compressing their optic apparatus may also have concomitant age-related visual pathology such as cataracts. How these two pathologies interact with each other is not well documented. OBJECTIVE: The interaction between these two pathologies in elderly patients is the subject of this study. METHODS: We identified a series of non-functioning macroadenoma patients over age 50 years with tumors compressing the chiasm who underwent transsphenoidal surgery at our institution between 2004 and 2018. Pre- and post-operative visual complaints, tumor size and extent of resection were analyzed. Prevalence of the diagnosis of cataract and prevalence of cataract surgery in each decade were compared with national averages. RESULTS: We identified 200 patients who met selection criteria. 18% of these patients had a diagnosis of cataract and 12.5% had cataract surgery. Compared with the Eye Diseases Prevalence Research Group (EDPRG) study, the prevalence of cataract surgery was 2.5 times the national average of 5.1%. 32% of these patients had no improvement in their vision after cataract surgery but 76% improved after transsphenoidal surgery. CONCLUSIONS: We reported a high prevalence of cataract surgery in patients over age 50 in patients with pituitary macroadenomas compressing the optic pathway compared with national averages in patients without adenomas. While visual loss from adenoma likely precipitated more cataract surgeries in this group of patients, some who may not have required it, those patients with cataracts who did not have their cataracts extracted were less likely to recover vision after transsphenoidal surgery. Addressing both pathologies is beneficial.

Anterior communicating artery division in the endoscopic endonasal translamina terminalis approach to the third ventricle: an anatomical feasibility study.

BACKGROUND: Endonasal endoscopic approaches (EEA) to the third ventricle are well described but generally use an infrachiasmatic route since the suprachiasmatic translamina terminalis corridor is blocked by the anterior communicating artery (AComA). The bifrontal basal interhemispheric translamina terminalis approach has been facilitated with transection of the AComA. The aim of the study is to describe the anatomical feasibility and limitations of the EEA translamina terminalis approach to the third ventricle augmented with AComA surgical ligation. METHODS: Endoscopic dissections were performed on five cadaveric heads injected with colored latex using rod lens endoscopes attached to a high-definition camera and a digital video recorder system. A stepwise anatomical dissection of the endoscopic endonasal transtuberculum, transplanum, translamina terminalis approach to the third ventricle was performed. Measurements were performed before and after AComA elevation and transection using a millimeter flexible caliper. RESULTS: Multiple comparison statistical analysis revealed a statistically significant difference in vertical exposure between the control condition and after AComA elevation, between the control condition and after AComA division and between the AComA elevation and division (p < 0.05). The mean difference in exposed surgical area was statistically significant between the control and after AComA division and between elevation and AComA division (p < 0.01), whereas it was not statistically significant between the control condition and AComA elevation (NS). CONCLUSION: The anatomical feasibility of clipping and dividing the AComA through an EEA has been demonstrated in all the cadaveric specimens. The approach facilitates exposure of the suprachiasmatic optic recess within the third ventricle that may be a blind spot during an infrachiasmatic approach.

Endonasal surgery for suprasellar germ cell tumors: two cases and review of the literature.

Germ cell tumors are rare malignant tumors frequently located in the suprasellar region. Definitive treatment is chemotherapy and radiation. However, in some circumstances, surgery is indicated for biopsy or resection. There are limited reports of the role of the endonasal endoscopic approach (EEA) in the management of this tumor. We present two cases in which EEA was utilized for successful management of germ cell tumor. The most challenging aspect of germ cell tumor management for the treating physician is knowing the proper indications for surgery. In this paper, we highlight two specific instances, namely diagnosis and tumor refractory to chemoradiation. Given the suprasellar location, EEA is an ideal approach.

BRAF V600E mutant papillary craniopharyngiomas: a single-institutional case series.

PURPOSE: To describe the clinical, radiographic and surgical outcomes in a cohort of patients with BRAF V600E mutant papillary craniopharyngiomas. METHODS: A retrospective review was performed to identify all patients with a histological diagnosis of CP operated upon at a single institution between 2005 and 2017. All cases with adequate material were sequenced to confirm the presence of BRAF V600E mutation. RESULTS: Sixteen patients were included in the present study. Approach was endoscopic endonasal (EEA) in 14 and transcranial (TCA) in 2. All patients were adult with an average age of 50 years (24-88). Radiographic review demonstrated that the majority (93.7%) were suprasellar and twelve (75%) had third ventricular involvement. No tumor showed evidence of calcifications and 68.7% were mixed solid-cystic. All patients had some evidence of hypopituitarism and 62.5% had hypothalamic disturbances. GTR was achieved in 11/14 (78.6%) EEA and 0/2 (0%) TCA (p < 0.05). The mean length of stay was 17.5 days in the TCA group and 7.6 days in the EEA group (p < 0.05). There were no CSF leaks. Post-operatively, eleven (68.7%) developed new DI or new hypopituitarism. Nine increased their BMI with a mean increase of 12.3%, whereas six patients lost weight with a mean decrease of 5.3%. CONCLUSIONS: BRAF V600E mutant papillary tumors represent a clearly distinct clinical-pathological entity of craniopharyngiomas. These are generally non-calcified suprasellar tumors that occur in adults. These distinct characteristics may someday lead to upfront chemotherapy. When surgery is necessary, EEA may be preferred over TCA.

Radiation therapy rather than prior surgery reduces extent of resection during endonasal endoscopic reoperation for craniopharyngioma.

OBJECTIVE: Radiation therapy is often advocated for residual or recurrent craniopharyngioma following surgical resection to prevent local recurrence. However, radiation therapy is not always effective and may render tumors more difficult to remove. If this is the case, patients may benefit more from reoperation if gross total resection can be achieved. Nevertheless, there is little data on the impact of radiation on reoperations for craniopharyngioma. In this study, we sought to analyze whether a history of previous radiation therapy (RT) affected extent of resection in patients with recurrent craniopharyngiomas subsequently treated with reoperation via endoscopic endonasal approach (EEA). METHODS: The authors reviewed a prospectively acquired database of EEA reoperations of craniopharyngiomas over 13 years at Weill Cornell, NewYork-Presbyterian Hospital. All procedures were performed by the senior author. The operations were separated into two groups based on whether the patient had surgery alone (group A) or surgery and RT (group B) prior to recurrence. RESULTS: A total of 24 patients (16 male, 8 female) who underwent surgery for recurrent craniopharyngioma were identified. The average time to recurrence was 7.64 ± 4.34 months (range 3-16 months) for group A and 16.62 ± 12.1 months (range 6-45 months) for group B (p < 0.05). The average tumor size at recurrence was smaller in group A (1.85 ± 0.72 cm; range 0.5-3.2) than group B (2.59 ± 0.91 cm; range 1.5-4.6; p = 0.00017). Gross total resection (GTR) was achieved in 91% (10/11) of patients in group A and 54% (7/13) of patients in group B (p = 0.047). There was a near significant trend for higher average Karnofsky performance status (KPS) score at last follow-up for group A (83 ± 10.6) compared with group B (70 ± 16.3, p = 0.056). CONCLUSIONS: While RT for residual or recurrent craniopharyngioma may delay time to recurrence, ability to achieve GTR with additional surgery is reduced. In the case of recurrent craniopharyngioma, if GTR can be achieved, consideration should be given to endonasal reoperation prior to the decision to irradiate residual or recurrent tumor.

Transorbital endoscopic approach for exposure of the sylvian fissure, middle cerebral artery and crural cistern: an anatomical study.

BACKGROUND: The availability of minimal access instrumentation and endoscopic visualization has revolutionized the field of minimally invasive skull base surgery. The transorbital endoscopic approach using an eyelid incision has been proposed as a new minimally invasive technique for the treatment of skull base pathology, mostly extradural tumors. Our study aims to evaluate the anatomical aspects and potential role of the transorbital endoscopic approach for exposure of the sylvian fissure, middle cerebral artery and crural cistern. METHODS: An anatomical dissection was performed in four freshly injected cadaver heads (8 orbits) using 0- and 30-degree endoscopes. First, an endoscopic endonasal medial orbital decompression was done to facilitate medial retraction of the orbit. An endoscopic transorbital approach through an eyelid incision, with drilling of the posterior wall of the orbit and lesser sphenoidal wing, was then performed to expose the sylvian fissure and crural cisterns. A stepwise anatomical description of the approach and visualized anatomy is detailed. RESULTS: A superior eyelid incision followed by orbital retraction provided a surgical window of approximately 1.2 cm (range 1.0-1.5 cm) for endoscopic transorbital dissection. The superior (SOF) and inferior (IOF) orbital fissures represent the medial limits of the approach and are identified in the initial part of the procedure. Drilling of the orbital roof (lateral and superior to the SOF), greater sphenoidal wing (lateral to the SOF and IOF) and lesser sphenoidal wing exposed the anterior and middle fossa dura. A square-shaped dural opening provided visualization of the posterior orbital gyri, sylvian fissure and temporal pole. Intradural dissection allowed exposure of the sphenoidal portion of the sylvian fissure, M1, MCA bifurcation and M2 branches and lenticulostriate perforators. Dissection of the medial aspect of the sylvian and carotid cisterns with a 30-degree endoscope allowed exposure of the mesial temporal lobe and crural cistern. CONCLUSIONS: The transorbital endoscopic approach allows successful exposure of the sphenoidal portion of the sylvian fissure and M1 and M2 segments of the middle cerebral artery. Angled endoscopes may provide visualization of the mesial temporal lobe and crural cistern. Although our anatomical study demonstrates the feasibility of intradural dissection and closure via an endoscopic transorbital approach, further studies are necessary to evaluate its role in the clinical scenario.

Predictors and incidence of orthostatic headache associated with lumbar drain placement following endoscopic endonasal skull base surgery.

BACKGROUND: Orthostatic headache (OH) is a potential complication of lumbar drainage (LD) usage. The incidence and risk factors for OH with the use of lumbar drainage during endoscopic endonasal procedures have not been documented. OBJECTIVE: To investigate the incidence of post-procedure OHs associated with placement of LD in patients undergoing endoscopic endonasal procedures. METHODS: We prospectively noted the placement of LDs in a consecutive series of endoscopic endonasal skull base surgeries. Charts were retrospectively reviewed, and patients were divided into two groups: those with OH and those without. The patient demographics, drain durations, imaging findings of intracranial hypotension, pathologies and need for a blood patch were compared between the two groups. RESULTS: Two hundred forty-nine patients were included in the study. Seven patients (2.8%) suffered post-dural puncture OH, which was mild to moderate and disappeared 2-8 days (median 3 days) after treatment. Blood patches were used in four patients. Significant predisposing factors were age (33.0 vs. 53.5, P = 0.014) and a strong trend for female gender (85.7% vs. 47.9%, P = 0.062). BMI and drain duration were not significant. Postoperative intracranial hypotension was diagnosed radiographically in 43% of OH patients and in 5.4% of those without OH (P = 0.003). Four (1.6%) patients required treatment with an epidural blood patch. CONCLUSION: OH associated with intracranial hypotension in patients undergoing endoscopic endonasal procedures with LDs is an infrequent complication seen more commonly in young female patients. Radiographic signs of intracranial hypotension are a specific but not sensitive test for OH.

Three-dimensional volumetric measurements in defining endoscope-guided giant adenoma surgery outcomes.

PURPOSE: Maximum two-dimensional (2D) diameter has been used to define giant pituitary adenoma (GPA) surgery outcomes as has volume using an ellipsoid approximation of volumetrics. Cross sectional length can be measured in several different planes. We sought to compare the accuracy of different 2D cross sectional measurements with the 3D volumetric measurements for predicting GPA surgery outcomes. METHODS: Retrospective analysis was performed on a prospectively collected database. Tumors with >3 cm diameter were identified and classified based on maximal cross sectional measurements in three separate co-axial planes, i.e. transverse (TV), antero-posterior (AP) and cranio-caudal (CC). Volume was calculated using both MRI-guided volumetrics and an ellipsoid approximation (TV × AP × CC/2). Univariate and multivariate analysis was used to evaluate the relationship between cross sectional and volumetric data and extent of resection (EOR). RESULTS: In 62 subjects, median tumor volume using 3D volumetrics was 13.74 cm(3), which was overestimated by 16 % by the ellipsoid calculation (p = 0.0029), particularly for tumors >20 cm(3). Gross total resection (GTR) was 46.7 % and median EOR was 99.57 %. At 22-month follow-up, visual and anterior pituitary functions were stable (90 %) or improved (87 %). Pre-operative tumor volume >10 cm(3) (p = 0.02) and Knosp grade 3-4 (p = 0.04) were independent predictors of EOR. Knosp grade 3-4 (p < 0.0001), TV measurement >4 cm (p = 0.007) and maximum cross sectional length >4 cm (p = 0.04) were predictors of not achieving GTR. Only TV measurement (p = 0.02) predicted permanent diabetes insipidis. The smallest significant thresholds for predicting decreased GTR were TV measurement >25 mm, AP measurement >35 mm and volume >19 cm(3). CONCLUSION: We propose a new volumetric threshold of 20 cm(3) as most accurate for predicting GTR in the EEA era. CC measurement is the least useful predictor. Cavernous sinus invasion remains the best predictor of incomplete resection.

Endoscopic endonasal versus open transcranial resection of craniopharyngiomas: a case-matched single-institution analysis.

OBJECTIVE The authors compared clinical and radiological outcomes after resection of midline craniopharyngiomas via an endoscopic endonasal approach (EEA) versus an open transcranial approach (TCA) at a single institution in a series in which the tumors were selected to be equally amenable to gross-total resection (GTR) with either approach. METHODS A single-institution retrospective review of previously untreated adult midline craniopharyngiomas was performed. Lesions were evaluated by 4 neurosurgeons blinded to the actual approach used to identify cases that were equally amenable to GTR using either an EEA or TCA. Radiological and clinical outcome data were assessed. RESULTS Twenty-six cases amenable to either approach were identified, 21 EEA and 5 TCA. Cases involving tumors that were resected via a TCA had a trend toward larger diameter (p = 0.10) but were otherwise equivalent in preoperative clinical and radiological characteristics. GTR was achieved in a greater proportion of cases removed with an EEA than a TCA (90% vs 40%, respectively; p = 0.009). Endoscopic resection was associated with superior visual restoration (63% vs 0%; p < 0.05), a decreased incidence of recurrence (p < 0.001), lower increase in FLAIR signal postoperatively (-0.16 ± 4.6 cm3 vs 14.4 ± 14.0 cm3; p < 0.001), and fewer complications (20% vs 80% of patients; p < 0.001). Significantly more TCA patients suffered postoperative cognitive loss (80% vs 0; p < 0.0001). CONCLUSIONS An EEA is a safe and effective approach to suprasellar craniopharyngiomas amenable to GTR. For this select group of cases, the EEA may provide higher rates of GTR and visual improvement with fewer complications compared with a TCA.

The rhinopalatine line as a reliable predictor of the inferior extent of endonasal odontoidectomies.

OBJECT: The endoscopic endonasal approach (EEA) provides a minimally invasive corridor through which the cervicomedullary junction can be decompressed with reduced morbidity rates compared to those with the classic transoral approaches. The limit of the EEA is its inferior extent, and preoperative estimation of its reach is vital for determining its suitability. The aim of this study was to evaluate the actual inferior limit of the EEA in a surgical series of patients and develop an accurate and reliable predictor that can be used in planning endonasal odontoidectomies. METHODS: The actual inferior extent of surgery was determined in a series of 6 patients with adequate preoperative and postoperative imaging who underwent endoscopie endonasal odontoidectomy. The medians of the differences between several previously described predictive lines, namely the nasopalatine line (NPL) and nasoaxial line (NAxL), were compared with the actual surgical limit and the hard-palate line by using nonparametric statistics. A novel line, called the rhinopalatine line (RPL), was established and corresponded best with the actual limit of the surgery. RESULTS: There were 4 adult and 2 pediatric patients included in this study. The NPL overestimated the inferior extent of the surgery by an average (± SD) of 21.9 ± 8.1 mm (range 14.7-32.5 mm). The NAxL and RPL overestimated the inferior limit of surgery by averages of 6.9 ± 3.8 mm (range 3.7-13.3 mm) and 1.7 ± 3.7 mm (range -2.8 to 8.3 mm), respectively. The medians of the differences between the NPL and NAxL and the actual surgery were statistically different (both p = 0.0313). In contrast, there was no statistically significant difference between the RPL and the inferior limit of surgery (p = 0.4375). CONCLUSIONS: The RPL predicted the inferior limit of the EEA to the craniovertebral junction more accurately than previously described lines. The use of the RPL may help surgeons in choosing suitable candidates for the EEA and in selecting those for whom surgery through the oropharynx or the facial bones is the better approach.

Endoscopic endonasal resection of skull base meningiomas: the significance of a "cortical cuff" and brain edema compared with careful case selection and surgical experience in predicting morbidity and extent of resection.

OBJECT: This paper describes a consecutive series of skull base meningiomas resected using an endoscopic endonasal approach through various corridors at a single institution over 7 years. The impact of case selection and experience, the presence of a cortical cuff between the tumor and surrounding vessels, and brain edema on morbidity and rates of gross-total resection (GTR) were examined. METHODS: A retrospective review of a series of 46 skull base meningiomas from a prospective database was conducted. The series of cases were divided by location: olfactory groove (n = 15), tuberculum and planum (n = 20), sellar/cavernous (n = 9) and petroclival (n = 2). Gross-total resection was never intended in the sellar/cavernous tumors, which generally invaded the cavernous sinus. Clinical charts, volumetric imaging, and pathology were reviewed to assess the extent of resection and complications. Cases were divided based on a time point in which surgical technique and case selection improved into Group 1 (surgery prior to June 2008; n = 21) and Group 2 (surgery after June 2008; n = 25) and into those with and without a cortical cuff and with and without brain edema. RESULTS: Improved case selection had the greatest impact on extent of resection. For the entire cohort, rates of GTR went from 38% to 76% (p = 0.02), and for cases in which GTR was the intent, the rates went from 63% to 84% (not significant), which was mostly driven by the planum and tuberculum meningiomas, which went from 75% to 91.7 % (nonsignificant difference). The presence of a cortical cuff and brain edema had no impact on outcomes. There were 3 CSF leaks (6.5%) but all were in Group 1. Hence, CSF leak improved from 14.2% to 0% with surgical experience. Lessons learned for optimal case selection are discussed. CONCLUSIONS: Surgical outcome for endonasal endoscopic resection of skull base meningiomas depends mostly on careful case selection and surgical experience. Imaging criteria such as the presence of a cortical cuff or brain edema are less important.

Surgical management of trigeminal schwannomas: defining the role for endoscopic endonasal approaches.

OBJECT: Because multiple anatomical compartments are involved, the surgical management of trigeminal schwannomas requires a spectrum of cranial base approaches. The endoscopic endonasal approach to Meckel's cave provides a minimal access corridor for surgery, but few reports have assessed outcomes of the procedure or provided guidelines for case selection. METHODS: A prospectively acquired database of 680 endoscopic endonasal cases was queried for trigeminal schwannoma cases. Clinical charts, radiographic images, and long-term outcomes were reviewed to determine outcome and success in removing tumor from each compartment traversed by the trigeminal nerve. RESULTS: Four patients had undergone endoscopic resection of trigeminal schwannomas via the transpterygoid approach (mean follow-up 37 months). All patients had disease within Meckel's cave, and 1 patient had extension into the posterior fossa. Gross-total resection was achieved in 3 patients whose tumors were purely extracranial. One patient with combined Meckel's cave and posterior fossa tumor had complete resection of the extracranial disease and 52% resection of the posterior fossa disease. One patient with posterior fossa disease experienced a sixth cranial nerve palsy in addition to a corneal keratopathy from worsened trigeminal neuropathy. There were no CSF leaks. Over the course of the study, 1 patient with subtotal resection required subsequent stereotactic radiosurgery for disease progression within the posterior fossa. CONCLUSIONS: Endoscopic endonasal approaches appear to be well suited for trigeminal schwannomas restricted to Meckel's cave and/or extracranial segments of the nerve. Lateral transcranial skull base approaches should be considered for patients with posterior fossa disease. Further multiinstitutional studies will be necessary for adequate power to help determine relative indications between endoscopic and transcranial skull base approaches.

The lateral transorbital approach to the medial sphenoid wing, anterior clinoid, middle fossa, cavernous sinus, and Meckel's cave: target-based classification, approach-related complications, and intermediate-term ocular outcomes.

OBJECTIVE: The lateral transorbital approach (LTOA) is a relatively new minimal access skull base approach suited for addressing paramedian pathology of the anterior and middle fossa. The authors define target zones for this approach and describe a series of cases with detailed measurements of visual outcomes, including those obtained with exophthalmometry. METHODS: The authors performed a retrospective analysis of a consecutive series of LTOA patients. Seven target zones were identified: 1) the orbit, 2) the lesser sphenoid wing and anterior clinoid, 3) the middle fossa, 4) the lateral wall of the cavernous sinus and Meckel's cave, 5) the infratemporal fossa, 6) the petrous apex, and 7) the anterior fossa. The authors used volumetric analyses of preoperative and postoperative MR and CT imaging data to calculate the volume of bone and tumor removed and to provide detailed ophthalmological, neurological, and cosmetic outcomes. RESULTS: Of the 20 patients in this cohort, pathology was in zone 2 (n = 10), zone 4 (n = 6), zone 3 (n = 2), zone 1 (n = 1), and zone 5 (n = 1). Pathology was meningioma (n = 10), schwannoma (n = 2), metastasis (n = 2), epidermoid (n = 1), dermoid (n = 1), encephalocele (n = 1), adenoma (n = 1), glioblastoma (n = 1), and inflammatory lesion (n = 1). The goal was gross-total resection (GTR) in 9 patients, all of whom achieved GTR. Subtotal resection (STR) was the goal in 8 patients (5 spheno-orbital meningiomas, 1 giant cavernous sinus/Meckel's cave schwannoma, 1 cavernous sinus prolactinoma, and 1 cavernous sinus dermoid), 7 of whom achieved STR and 1 of whom achieved GTR. The goal was biopsy in 2 patient and repair of encephalocele in 1. Visual acuity was stable or improved in 18 patients and worse in 2. Transient early postoperative diplopia, ptosis, eyelid swelling, and peri-orbital numbness were common. All 9 patients with preoperative diplopia improved at their last follow-up. Seven of 8 patients with preoperative exophthalmos improved after surgery (average correction of 64%). There were no cases of clinically significant (> 2 mm) postoperative enophthalmos. The most frequent postoperative complaint was peri-orbital numbness (40%). There was 1 CSF leak. Most patients were satisfied with their ocular (84%-100% of patients provided positive satisfaction-related responses) and cosmetic (75%-100%) outcomes. CONCLUSIONS: The LTOA is a safe minimal access approach to a variety of paramedian anterior skull base pathologies in several locations. Early follow-up revealed excellent resolution of exophthalmos with little risk of clinically significant enophthalmos. Transient diplopia, ptosis, and peri-orbital numbness were common but improved. Careful case selection is critical to ensure good outcome.

Endonasal, supraorbital, and transorbital approaches: minimal access endoscope-assisted surgical approaches for meningiomas in the anterior and middle cranial fossae.

OBJECTIVE: Minimally invasive endoscope-assisted approaches to the anterior skull base offer an alternative to traditional open craniotomies. Given the restrictive operative corridor, appropriate case selection is critical for success. In this paper, the authors present the results of three different minimal access approaches to meningiomas of the anterior and middle fossae and examine the differences in the target areas considered appropriate for each approach, as well as the outcomes, to determine whether the surgical goals were achieved. METHODS: A consecutive series of the endoscopic endonasal approach (EEA), supraorbital approach (SOA), or transorbital approach (TOA) for newly diagnosed meningiomas of the anterior and middle fossa skull base between 2007 and 2022 were examined. Probabilistic heat maps were created to display the distribution of tumor volumes for each approach. Gross-total resection (GTR), extent of resection, visual and olfactory outcomes, and postoperative complications were assessed. RESULTS: Of 525 patients who had meningioma resection, 88 (16.7%) were included in this study. EEA was performed for planum sphenoidale and tuberculum sellae meningiomas (n = 44), SOA for olfactory groove and anterior clinoid meningiomas (n = 36), and TOA for spheno-orbital and middle fossa meningiomas (n = 8). The largest tumors were treated using SOA (mean volume 28 ± 29 cm3), followed by TOA (mean volume 10 ± 10 cm3) and EEA (mean volume 9 ± 8 cm3) (p = 0.024). Most cases (91%) were WHO grade I. GTR was achieved in 84% of patients (n = 74), which was similar to the rates for EEA (84%) and SOA (92%), but lower than that for TOA (50%) (p = 0.002), the latter attributable to spheno-orbital (GTR: 33%) not middle fossa (GTR: 100%) tumors. There were 7 (8%) CSF leaks: 5 (11%) from EEA, 1 (3%) from SOA, and 1 (13%) from TOA (p = 0.326). All resolved with lumbar drainage except for 1 EEA leak that required a reoperation. CONCLUSIONS: Minimally invasive approaches for anterior and middle fossa skull base meningiomas require careful case selection. GTR rates are equally high for all approaches except for spheno-orbital meningiomas, where alleviation of proptosis and not GTR is the primary goal of surgery. New anosmia was most common after EEA.

Endoscopic endonasal repair of encephaloceles of the lateral sphenoid sinus: multiinstitution confirmation of a new classification.

OBJECTIVE: Encephaloceles of the lateral sphenoid sinus are rare. Originally believed to be due to defects in a patent lateral craniopharyngeal canal (Sternberg canal), they are now thought to originate more commonly from idiopathic intracranial hypertension, not unlike encephaloceles elsewhere in the skull base. A new classification of these encephaloceles was recently introduced, which divided them in relation to the foramen rotundum. Whether this classification can be applied to a larger cohort from multiple institutions and whether it might be useful in predicting outcome is unknown. Thus, the authors' goal was to divide a multiinstitutional cohort of patients with lateral sphenoid encephaloceles into four subtypes to determine their incidence and any correlation with surgical outcome. METHODS: A multicenter retrospective review of prospectively acquired databases was carried out across three institutions. Cases were categorized into one of four subtypes (type I, Sternberg canal; type II, medial to rotundum; type III, lateral to rotundum; and type IV, both medial and lateral with rotundum enlargement). Demographic and outcome metrics were collected. Kaplan-Meyer curves were used to determine the rate of recurrence after surgical repair. RESULTS: A total of 49 patients (71% female) were included. The average BMI was 32.8. All encephaloceles fell within the classification scheme. Type III was the most common (71.4%), followed by type IV (16.3%), type II (10.2%), and type I (2%). Cases were repaired endonasally, via a transpterygoidal approach. Lumbar drains were placed in 78% of cases. A variety of materials was used for closure, with a nasoseptal flap used in 65%. After a mean follow-up of 47 months, there were 4 (8%) CSF leak recurrences, all in patients with type III or type IV leaks and all within 1 year of the first repair. Two leaks were fixed with ventriculoperitoneal shunt and reoperation, 1 with ventriculoperitoneal shunt only, and 1 with a lumbar drain only. Of 45 patients in whom detailed information was available, there were 12 (26.7%) with postoperative dry eye or facial numbness, with facial numbness occurring in type III or type IV defects only. CONCLUSIONS: Endoscopic endonasal repair of lateral sphenoid wing encephaloceles is highly successful, but repair may lead to dry eye or facial numbness. True Sternberg (type I) leaks were uncommon. Failures and facial numbness occurred only in patients with type III and type IV leaks.