AXL receptor is required for Zika virus strain MR-766 infection in human glioblastoma cell lines

Recent reports have shown that Zika virus (ZIKV) has oncolytic potential against human glioblastoma (GBM); however, the mechanisms underlying its tropism and cell entry are not completely understood. The receptor tyrosine kinase AXL has been identified as an entry receptor for ZIKV in a cell-type-specific manner. Interestingly, AXL is frequently overexpressed in GBM patients. Using commercially available GBM cell lines, we first show that cells expressing AXL are permissive for ZIKV infection, while cells that do not express AXL are not. Furthermore, inhibition of AXL kinase using R428 and antibody blockade of AXL receptor strongly attenuated virus entry in GBM cell lines. Additionally, CRISPR knockout of the AXL gene in GBM cell lines completely abolished ZIKV infection, significantly inhibited viral replication, and significantly reduced apoptosis compared with parental lines. Lastly, introduction of AXL receptor into non-expressing cell lines renders the cells susceptible to ZIKV infection. Together, these findings demonstrate that ZIKV entry into GBM cells in vitro is mediated by the AXL receptor and that following cell entry, productive infection is cytotoxic. Thus, ZIKV is a potential oncolytic virus for GBM.

The Role of 3D Tractography in Skull Base Surgery: Technological Advances, Feasibility, and Early Clinical Assessment with Anterior Skull Base Meningiomas

Objective  The aim of this study is to determine feasibility of incorporating three-dimensional (3D) tractography into routine skull base surgery planning and analyze our early clinical experience in a subset of anterior cranial base meningiomas (ACM). Methods  Ninety-nine skull base endonasal and transcranial procedures were planned in 94 patients and retrospectively reviewed with a further analysis of the ACM subset. Main Outcome Measures  (1) Automated generation of 3D tractography; (2) co-registration 3D tractography with computed tomography (CT), CT angiography (CTA), and magnetic resonance imaging (MRI); and (3) demonstration of real-time manipulation of 3D tractography intraoperatively. ACM subset: (1) pre- and postoperative cranial nerve function, (2) qualitative assessment of white matter tract preservation, and (3) frontal lobe fluid-attenuated inversion recovery (FLAIR) signal abnormality. Results  Automated 3D tractography, with MRI, CT, and CTA overlay, was produced in all cases and was available intraoperatively. ACM subset : 8 (44%) procedures were performed via a ventral endoscopic endonasal approach (EEA) corridor and 12 (56%) via a dorsal anteromedial (DAM) transcranial corridor. Four cases (olfactory groove meningiomas) were managed with a combined, staged approach using ventral EEA and dorsal transcranial corridors. Average tumor volume reduction was 90.3 ± 15.0. Average FLAIR signal change was -30.9% ± 58.6. 11/12 (92%) patients (DAM subgroup) demonstrated preservation of, or improvement in, inferior fronto-occipital fasciculus volume. Functional cranial nerve recovery was 89% (all cases). Conclusion  It is feasible to incorporate 3D tractography into the skull base surgical armamentarium. The utility of this tool in improving outcomes will require further study.

White Matter Governed Superior Frontal Sulcus Surgical Paradigm: A Radioanatomic Microsurgical Study-Part II

BACKGROUND

Kocher's point (KP) and its variations have provided standard access to the frontal horn (FH) for over a century. Anatomic understanding of white matter tracts (WMTs) has evolved, now positioning us to better inform the optimal FH trajectory.

OBJECTIVE

To (1) undertake a literature review analyzing entry points (EPs) to the FH; (2) introduce a purpose-built WMT-founded superior frontal sulcus parafascicular (SFSP)-EP also referred to as the Kassam-Monroy entry point (KM-EP); and (3) compare KM-EP with KP and variants with respect to WMTs.

METHODS

(1) Literature review (PubMed database, 1892-2018): (a) stratification based on the corridor: i. ventricular catheter; ii. through-channel endoscopic; or iii. portal; (b) substratification based on intent: i. preoperatively planned or ii. intraoperative (postdural opening) for urgent ventricular drainage. (2) Anatomic comparisons of KM-EP, KP, and variants via (a) cadaveric dissections and (b) magnetic resonance-diffusion tensor imaging computational 3D modeling.

RESULTS

A total of 31 studies met inclusion criteria: (a) 9 utilized KP coordinate (1 cm anterior to the coronal suture (y-axis) and 3 cm lateral of the midline (x-axis) approximated by the midpupillary line) and 22 EPs represented variations. All 31 traversed critical subcortical WMTs, specifically the frontal aslant tract, superior longitudinal fasciculus II, and inferior fronto-occipital fasciculus, whereas KM-EP (x = 2.3, y = 3.5) spares these WMTs.

CONCLUSION

KP (x = 3, y = 1) conceived over a century ago, prior to awareness of WMTs, as well as its variants, anatomically place critical WMTs at risk. The KM-EP (x = 2.3, y = 3.5) is purpose built and founded on WMTs, representing anatomically safe access to the FH. Correlative clinical safety, which will be directly proportional to the size of the corridor, is yet to be established in prospective studies.

Endonasal Odontoidectomy in Basilar Invagination

Objective  The endoscopic endonasal odontoidectomy (EEO) is emerging as a feasible surgical alternative to conventional microscopic transoral approach. In this article, we show EEO in the basilar invagination (BI) and describe in detail the technical aspects, advantages, and disadvantages of this approach ( Fig. 1 ).

Methods  We describe EEO using audiovisual material from the neurosurgical department of Hospital Universitari i Politècnic La Fe Valencia database.

Results  We present the case of a 61-year-old male patient with BI. Initially, we performed suboccipital decompression and occipitocervical fusion. Subsequently, after a no significant neurological improvement and persistent anterior compression, EEO was performed. The postoperative evolution was uneventful and the preoperative neurological deficits were recovered rapidly after surgery

Discussion  EEO technique enables complete odontoid resection, preventing invasion of aggressive oral bacterial flora, and it is not limited by the mouth opening. As well, it avoids manipulation of the soft palate, therefore evades the risk of velopalatal insufficiency, facilitates immediate oral tolerance, and early extubation. The rostral position of C1–C2 complex in BI could suppose a great advantage in favor the endonasal approaches. Mucoperichondrial vascularized flaps could be obtained to avoid a postoperative cerebrospinal fluid (CSF) leak and facilitate the reepithelization process of the surgical bed.

Conclusion  EEO may provide a significant anatomic and technical advantage over the trans-oral approach.

The link to the video can be found at: https://youtu.be/Td6MDcjCNKk .

White Matter-Governed Superior Frontal Sulcus Surgical Paradigm: A Radioanatomic Microsurgical Study—Part I

BACKGROUND

Frontal subcortical and intraventricular pathologies are traditionally accessed via transcortical or interhemispheric-transcallosal corridors.

OBJECTIVE

To describe the microsurgical subcortical anatomy of the superior frontal sulcus (SFS) corridor.

METHODS

Cadaveric dissections were undertaken and correlated with magnetic resonance imaging/diffusion-tensor imaging-Tractography. Surgical cases demonstrated clinical applicability.

RESULTS

SFS was divided into the following divisions: proximal, precentral sulcus to coronal suture; middle, 3-cm anterior to coronal suture; and distal, middle division to the orbital crest. Anatomy was organized as layered circumferential rings projecting radially towards the ventricles: (1) outer ring: at the level of the SFS, the following lengths were measured: (A) precentral sulcus to coronal suture = 2.29 cm, (B) frontal bone projection of superior sagittal sinus (SSS) to SFS = 2.37 cm, (C) superior temporal line to SFS = 3.0 cm, and (D) orbital crest to distal part of SFS = 2.32 cm; and (2) inner ring: (a) medial to SFS, U-fibers, frontal aslant tract (FAT), superior longitudinal fasciculus I (SLF-I), and cingulum bundle, (b) lateral to SFS, U-fibers, (SLF-II), claustrocortical fibers (CCF), and inferior fronto-occipital fasciculus, and (c) intervening fibers, FAT, corona radiata, and CCF. The preferred SFS parafascicular entry point (SFSP-EP) also referred to as the Kassam-Monroy entry point (KM-EP) bisects the distance between the midpupillary line and the SSS and has the following coordinates: x = 2.3 cm (lateral to SSS), y ≥ 3.5 cm (anterior to CS), and z = parallel corona radiata and anterior limb of the internal capsule.

CONCLUSION

SFS corridor can be divided into lateral, medial, and intervening white matter tract segments. Based on morphometric assessment, the optimal SFSP-EP is y ≥ 3.5 cm, x = 2.3 cm, and z = parallel to corona radiata and anterior limb of the internal capsule.

A Feasibility Study of Lavender Aromatherapy in an Awake Craniotomy Environment

PURPOSE

Integrative medicine interventions are needed for awake craniotomies, as many patients experience anxiety. Lavender aromatherapy significantly reduces anxiety or pain in a variety of surgical procedures. This feasibility study used lavender aromatherapy during awake craniotomies to determine the number of patients who would consent and complete the study, the technicality of lavender aromatherapy use, and acceptance by operating room (OR) staff.

METHODS

We approached 40 consecutive patients (≥18 years old). Exclusion criteria were pulmonary issues or sensitivity to lavender. Outcome measures in consented patients were enrollment and completion rates, anxiety and pain as measured by the Visual Analog Scale for Anxiety (VAS-A) and Visual Analog Scale for Pain (VAS-P), and satisfaction with pain control using the Patient Opinion of Pain Management (POPM) survey.

RESULTS

Of the 40 patients approached, 4 declined participation or had their surgery cancelled. Of the remaining 36, 4 required increased sedation during surgery and 1 was unable to detect lavender. Thus, 31 patients (77.5%) completed the study. VAS-A and VAS-P scores trended lower after lavender inhalation, but the difference did not reach statistical significance. There was a slight increase in VAS-P score at the OR1 time point. Expectancy for reduction in both anxiety and pain were not significantly different. Improvement in anxiety also was not different, while improvement in pain trended lower (P=0.025). POPM results indicated the majority of patients were either "satisfied" or "very satisfied" with pain management.

CONCLUSIONS

This study demonstrated 77.5% completion and the ability to integrate lavender aromatherapy into the OR. Thus, we plan to conduct a randomized clinical trial to assess efficacy of lavender aromatherapy.

The Surgical White Matter Chassis: A Practical 3-Dimensional Atlas for Planning Subcortical Surgical Trajectories

BACKGROUND

The imperative role of white matter preservation in improving surgical functional outcomes is now recognized. Understanding the fundamental white matter framework is essential for translating the anatomic and functional literature into practical strategies for surgical planning and neuronavigation.

OBJECTIVE

To present a 3-dimensional (3-D) atlas of the structural and functional scaffolding of human white matter-ie, a "Surgical White Matter Chassis (SWMC)"-that can be used as an organizational tool in designing precise and individualized trajectory-based neurosurgical corridors.

METHODS

Preoperative diffusion tensor imaging magnetic resonance images were obtained prior to each of our last 100 awake subcortical resections, using a clinically available 3.0 Tesla system. Tractography was generated using a semiautomated deterministic global seeding algorithm. Tract data were conceptualized as a 3-D modular chassis based on the 3 major fiber types, organized along median and paramedian planes, with special attention to limbic and neocortical association tracts and their interconnections.

RESULTS

We discuss practical implementation of the SWMC concept, and highlight its use in planning select illustrative cases. Emphasis has been given to developing practical understanding of the arcuate fasciculus, uncinate fasciculus, and vertical rami of the superior longitudinal fasciculus, which are often-neglected fibers in surgical planning.

CONCLUSION

A working knowledge of white matter anatomy, as embodied in the SWMC, is of paramount importance to the planning of parafascicular surgical trajectories, and can serve as a basis for developing reliable safe corridors, or modules, toward the goal of "zero-footprint" transsulcal access to the subcortical space.

An Anatomically-Based Endoscopic Endonasal Model to Navigate the Anterior Ventral Skull Base

BACKGROUND

Endoscopic endonasal approaches to access the sellar and parasellar regions are challenging in the face of anatomical variations or pathologic conditions. We propose an anatomically-based model including the orbitosellar line (OSL), critical oblique foramen line (COFL), and paramedial anterior line (PAL) facilitating safe, superficial-to-deep dissection triangulating upon the medial opticocarotid recess.

METHODS

Five cadaveric heads were dissected to systematically expose the OSL, COFL, and PAL, illustrated with image guidance. Application of the coordinate system and a 6-step dissection sequence is described.

RESULTS

The coordinate system consists of 1) the OSL, connecting a) the anterior orbital point, junction of the anterior buttress of the middle turbinate with the agger nasi region, located 34.3 ± 0.9 mm above the intersection of the vertical plane of the lacrimal crest, and the orthogonal plane of the maxillo-ethmoidal suture; b) the posterior orbital point, junction of the optic canal with the lamina papyracea, located 4 ± 0.7 mm below the posterior ethmoidal artery; and c) the medial opticocarotid recess; 2) COFL (15 ± 2.8 mm), connecting the palatovaginal canal, vidian canal, and foramen rotundum; and 3) PAL (39 ± 0.06 mm), connecting the vidian canal with the posterior ethmoidal artery.

CONCLUSIONS

OSL, COFL, and PAL form an anatomically-based model for the systematic exposure when accessing the parasellar and sellar regions. Preliminary anatomical data suggest that this model may be of value when normal anatomy is distorted by pathology or anatomic variations.

Abstract 3052: MGMT inhibition is associated with MAPK pathway inhibition and enhances Raf, MEK, ERK inhibitors and restores meaningful Temozolomide activity in melanoma

Braf and MEK inhibition leads to limited survival gains in melanoma. In this research we show that, in vitro, MGMT controls all MAPK pathway effectors. We show that triple lock - upstream and downstream, along the MAPK pathway - effectively restores durable Braf and MEK inhibitor activity and significantly sensitizes melanoma to Temozolomide. The advantage of a multiple lock approach on the MAPK pathway is substantiated by the lack of signaling cross talk. We briefly discuss how this simple MGMT based regulatory paradigm could be immediately exploited in the care of melanoma patients. We also show how this strategy was exploited in two, surviving, metastatic (to include CNS disease) melanoma patients who had failed Braf and MEK inhibition (2 and 5 years ago) who now show stable or negligible residual disease burden while continuing on an intermittent, low treatment density, combination regimen

Citation Format: George C. Bobustuc, Amin B. Kassam, Dmitry Bosenko, Deborah L. Donohoe, Richard A. Rovin, Santhi D. Konduri. MGMT inhibition is associated with MAPK pathway inhibition and enhances Raf, MEK, ERK inhibitors and restores meaningful Temozolomide activity in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3052.

Abstract P1-08-28: Impact of surgery and time to surgery on breast cancer survival in the United States, 2004–2014 (N=2,211,245)

Background: Surgery is very common for patients diagnosed with breast cancer. Its impact on survival depends on diagnostic, patient, tumor-related, and other-treatment factors. Moreover, time to surgery from the date of diagnosis is also a critical factor affecting outcome.

Objective: In this study we investigated the impact of surgery on survival in breast cancer patients using two methods: (1) multivariate regression; and (2) propensity score matching. For the patients undergoing surgical intervention, we aimed to identify the optimum time from diagnosis to surgery.

Methods: The study population was taken from the National Cancer Database over the years 2004 through 2014. Of 2,211,245 patients, 99.1% were female, 0.9% male, 85% non-Hispanic white, 10.5% black, 0.7% Hispanic, and 14.5% other races. Mean age of the patient population was 60.0 ± 13.4 years (range: 18–90). The majority of the patients (92.9%) underwent a surgical procedure.

Results: Overall, the patients who did not undergo surgery were 6.7 times more likely to die within the study time period (95% confidence interval [CI]: 6.7–6.8, p<0.001) than those who did. However, after adjusting for patients' demographics, tumor-related factors, cancer stages, and combination of other treatments, the risk for dying of patients without surgery was 2.3 times higher (hazard ratio [HR]: 2.3, 95% CI: 2.3–2.4, p<0.001). In the propensity-matched cohort of 51,630 patients that was divided equally into two groups — those who underwent surgery and those who did not — the risk of mortality remained 2.4 times higher for patients without surgery (HR: 2.4, 95% CI: 2.3–2.4, p<0.001). Regarding time to surgery from the date of diagnosis, patient survival was best for the patients whose time to surgery ranged from 31 to 60 days. The next best timeframe was 61 to 90 days, followed by 30 days or fewer, then 91 to 120 days, and finally 120 and more days (p<0.001).

Conclusion: Using two different statistical methods, surgery is clearly an independent predictor of survival for patients with breast cancer. After matching for other factors, patients not having surgery were more than twice as likely to die as their surgical counterparts. Time to surgery from the date of diagonosis confirmed ealier findings that surgery is most benificial within 2–3 months from the date of diangosis. These findings can provide clinical guidance to clinicians and patients for planning treatment.

Citation Format: Singh M, Konduri SD, Bobustuc GC, Rovin RA, Kassam AB. Impact of surgery and time to surgery on breast cancer survival in the United States, 2004–2014 (N=2,211,245) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-08-28.

Awake Surgical Management of Third Ventricular Tumors: A Preliminary Safety, Feasibility, and Clinical Applications Study

BACKGROUND

Endoscopic and microneurosurgical approaches to third ventricular lesions are commonly performed under general anesthesia.

OBJECTIVE

To report our initial experience with awake transsulcal parafascicular corridor surgery (TPCS) of the third ventricle and its safety, feasibility, and limitations.

METHODS

A total of 12 cases are reviewed: 6 colloid cysts, 2 central neurocytomas, 1 papillary craniopharyngioma, 1 basal ganglia glioblastoma, 1 thalamic glioblastoma, and 1 ependymal cyst. Lesions were approached using TPCS through the superior frontal sulcus. Pre-, intra-, and postoperative neurocognitive (NC) testing were performed on all patients.

RESULTS

No cases required conversion to general anesthesia. Awake anesthesia changed intraoperative management in 4/12 cases with intraoperative cognitive changes that required port re-positioning; 3/4 recovered. Average length of stay (LOS) was 6.1 d ± 6.6. Excluding 3 outliers who had preoperative NC impairment, the average LOS was 2.5 d ± 1.2. Average operative time was 3.00 h ± 0.44. Average awake anesthesia time was 5.05 h ± 0.54. There were no mortalities.

CONCLUSION

This report demonstrated the feasibility and safety of awake third ventricular surgery, and was not limited by pathology, size, or vascularity. The most significant factor impacting LOS was preoperative NC deficit. The most significant risk factor predicting a permanent NC deficit was preoperative 2/3 domain impairment combined with radiologic evidence of invasion of limbic structures – defined as a “NC resilience/reserve” in our surgical algorithm. Larger efficacy studies will be required to demonstrate the validity of the algorithm and impact on long-term cognitive outcomes, as well as generalizability of awake TPCS for third ventricular surgery.

Racial Disparity Among Women Diagnosed With Invasive Breast Cancer in a Large Integrated Health System

Purpose

Reasons for the well-described disparity in outcomes between African American (AA) and non-Hispanic white (NHW) women with invasive breast cancer are unclear, making it difficult to identify solutions. This study examined the effects of demographics, biomarkers, tumor characteristics, cancer stage, morphology, and treatment variables on overall and cancer-free survival in these patient populations.

Methods

We retrospectively reviewed data for 6231 patients diagnosed with invasive breast cancer throughout an integrated health system from January 2006 through March 2015. Included for analysis were 5023 NHW and 413 AA women. All category and continuous variables in the study were described in the two groups using appropriate statistics. Kaplan-Meier method of survival with log-rank test was used to compare the two racial groups (NHW and AA). Cox proportional hazards regression was used to find hazard ratios for the predictors of survival and recurrence-free survival probability. Propensity probability match method (1:1) was used to match 319 NSW women to 319 similar AA women. Matching was done using all significant predictors, including demographic variables.

Results

Compared to NHW women, AA women presented with invasive breast cancer at a younger age (P<0.001) and had a higher proportion of stage IV cancers (P<0.001), which were more often infiltrating ductal carcinoma (P<0.003) and poorly differentiated (P<0.001). Within 10-year follow-up, AA women had shorter overall and recurrence-free survival (log-rank P<0.001), were 1.4 times more likely to die (P=0.009), and were twice as likely to have recurrence (P<0.001) than NHW women. In the matched groups, overall survival was similar for AA and NHW (log-rank P=0.0793); however, recurrence-free survival was higher in NHW than in AA women (P=0.047).

Conclusions

When presenting characteristics of AA and NHW women with invasive breast cancer are matched, disparity in overall mortality and rate of recurrence appears to be reduced or perhaps eliminated, suggesting invasive breast cancers in AA and NHW women respond similarly to treatment. Further study is needed to explore the true effect of biological factors; however, rectifying delivery of and access to care might be expected to mitigate, in large part, the racial disparity currently seen in breast cancer outcomes.

MGMT inhibition in ER positive breast cancer leads to CDC2, TOP2A, AURKB, CDC20, KIF20A, Cyclin A2, Cyclin B2, Cyclin D1, ERα and Survivin inhibition and enhances response to temozolomide

The DNA damage repair enzyme, O6-methylguanine DNA methyltransferase (MGMT) is overexpressed in breast cancer, correlating directly with estrogen receptor (ER) expression and function. In ER negative breast cancer the MGMT promoter is frequently methylated. In ER positive breast cancer MGMT is upregulated and modulates ER function. Here, we evaluate MGMT's role in control of other clinically relevant targets involved in cell cycle regulation during breast cancer oncogenesis. We show that O6-benzylguanine (BG), an MGMT inhibitor decreases CDC2, CDC20, TOP2A, AURKB, KIF20A, cyclin B2, A2, D1, ERα and survivin and induces c-PARP and p21 and sensitizes ER positive breast cancer to temozolomide (TMZ). Further, siRNA inhibition of MGMT inhibits CDC2, TOP2A, AURKB, KIF20A, Cyclin B2, A2 and survivin and induces p21. Combination of BG+TMZ decreases CDC2, CDC20, TOP2A, AURKB, KIF20A, Cyclin A2, B2, D1, ERα and survivin. Temozolomide alone inhibits MGMT expression in a dose and time dependent manner and increases p21 and cytochrome c. Temozolomide inhibits transcription of TOP2A, AURKB, KIF20A and does not have any effect on CDC2 and CDC20 and induces p21. BG+/-TMZ inhibits breast cancer growth. In our orthotopic ER positive breast cancer xenografts, BG+/-TMZ decreases ki-67, CDC2, CDC20, TOP2A, AURKB and induces p21 expression. In the same model, BG+TMZ combination inhibits breast tumor growth in vivo compared to single agent (TMZ or BG) or control. Our results show that MGMT inhibition is relevant for inhibition of multiple downstream targets involved in tumorigenesis. We also show that MGMT inhibition increases ER positive breast cancer sensitivity to alkylator based chemotherapy.

Abstract 4831: DSF-Cu complex sensitizes patient-derived unmethylated MGMT expressing brain tumor cells to temozolomide

Introduction: O6 methylguanine DNA methyltransferase (MGMT) repairs the DNA damage caused by alkylating agents [temozolomide (TMZ)] leading to chemoresistence. Members of the aldehyde dehydrogenase (ALDH) family of isoenzymes serve as markers of cancer stem cells and contribute to chemotherapy resistance. Disulfiram (DSF) inhibits MGMT through ubiquitin mediated degradation; it is also a specific inhibitor of ALDH. We therefore, hypothesized that DSF through MGMT and ALDH inhibition decreases stemness and sensitizes GBM cells to TMZ.

Methods: Normal astrocytes as well as established MGMT expressing GBM cell lines (LN18, T98G, U138, U118) and MGMT expressing (unmethylated) patient derived glioblastoma cells (ANII 7730 and ANII 7754) were treated with DSF/Cu +/- TMZ in various doses and combinations. We have also evaluated MGMT, ALDH levels and Sox2 expression. Cell viability, apoptotic assay and caspase 3/7 assay were used to evaluate inhibitory effect of various treatment combinations.

Results: DSF and TMZ have a minimal effect on normal astrocyte growth. DSF alone inhibited MGMT in established MGMT expressing glioblastoma cells (5 to 10 µM). DSF alone was unable to inhibit MGMT in patient derived brain tumor cells (up to 20µM). Addition of copper (&lt;/=1µM) significantly inhibited MGMT (~ 90%) in patient derived GBM cells which correlated with significant growth inhibition even when DSF was used at low concentrations (&lt;/=1µM). This suggests that addition of copper to DSF may reduce any potential, dose dependent DSF related neurotoxicity. Temozolomide alone did not inhibit MGMT in established cell lines nor patient derived brain tumor cell lines (up to 1000µM). DSF+Cu further sensitized patient derived GBM cells to TMZ and significantly inhibited GBM cell growth (~ 95%) and did not inhibit normal astrocyte growth. Further DSF+Cu and DSF+Cu+TMZ combinations caused significant apoptotic cell death and significantly increased caspase 3/7 in patient derived unmethylated GBM cells. Similarly, combination of DSF+Cu and TMZ+DSF+Cu caused significant drop in ALDH activity in patient derived brain tumor cells compared to untreated controls and single agents. DSF induced ALDH and MGMT inhibition correlated with decrease in SOX2. MGMT expression canceled by CRISPR/Cas9 led to significant decrease in SOX2 expression in primary cell cultures.

Conclusions: Our findings suggest that DSF/Cu treatment, a dual MGMT and ALDH inhibitor, suppresses stemness. Furthermore, our results confirm that combination of TMZ and DSF/Cu significantly inhibited glioblastoma cell growth compared to TMZ alone and untreated controls.

Citation Format: George C. Bobustuc, Amin B. Kassam, Richard A. Rovin, Deborah Donohoe, Dmitry Bosenko, Santhi D. Konduri. DSF-Cu complex sensitizes patient-derived unmethylated MGMT expressing brain tumor cells to temozolomide [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4831.

The Safety and Feasibility of Image-Guided BrainPath-Mediated Transsulcul Hematoma Evacuation: A Multicenter Study

BACKGROUND

Subcortical injury resulting from conventional surgical management of intracranial hemorrhage may counteract the potential benefits of hematoma evacuation.

OBJECTIVE

To evaluate the safety and potential benefits of a novel, minimally invasive approach for clot evacuation in a multicenter study.

METHODS

The integrated approach incorporates 5 competencies: (1) image interpretation and trajectory planning, (2) dynamic navigation, (3) atraumatic access system (BrainPath, NICO Corp, Indianapolis, Indiana), (4) extracorporeal optics, and (5) automated atraumatic resection. Twelve neurosurgeons from 11 centers were trained to use this approach through a continuing medical education-accredited course. Demographical, clinical, and radiological data of patients treated over 2 years were analyzed retrospectively.

RESULTS

Thirty-nine consecutive patients were identified. The median Glasgow Coma Scale (GCS) score at presentation was 10 (range, 5-15). The thalamus/basal ganglion regions were involved in 46% of the cases. The median hematoma volume and depth were 36 mL (interquartile range [IQR], 27-65 mL) and 1.4 cm (IQR, 0.3-2.9 cm), respectively. The median time from ictus to surgery was 24.5 hours (IQR, 16-66 hours). The degree of hematoma evacuation was ≥90%, 75% to 89%, and 50% to 74% in 72%, 23%, and 5.0% of the patients, respectively. The median GCS score at discharge was 14 (range, 8-15). The improvement in GCS score was statistically significant ( P < .001). Modified Rankin Scale data were available for 35 patients. Fifty-two percent of those patients had a modified Rankin Scale score of ≤2. There were no mortalities.

CONCLUSION

The approach was safely performed in all patients with a relatively high rate of clot evacuation and functional independence.

Abstract 2035: MGMT inhibition leads to CDK4/6 inhibition and enhances palbociclib and abemaciclib activity in breast cancer

Background: MGMT (O6 methylguanine DNA methyltransferase), a DNA repair protein leading to chemotherapy resistance, increasingly studied for its cell cycle regulatory functions, also known to control ER expression and function, is overexpressed in a majority of cancers, including breast cancer. MGMT inhibition has been reported to restore ER function and sensitivity to hormonal therapy in tamoxifen resistant breast cancer. CDK4/6 is a cell cycle regulator targeted by a new class of drugs in the treatment of breast cancer in patients who had progressed during prior endocrine therapy. We investigated a potential correlative role between MGMT and CDK4/6 expression/activity. In this therapeutic context MGMT inhibition would have the dual role of increasing/restoring effect of endocrine therapy and facilitate activity of CDK4/6 inhibitors (Palbociclib and Abemaciclib).

Methods: We have tested the effect of Antabuse (disulfiram, DSF), as an MGMT inhibitor, at nontoxic doses, on the expression of CDK4/6, or in combination with Palbociclib (PB) or Abemaciclib (LY2835219 - LY) on ER+ breast cancer cells.

Results: DSF at very low doses (achievable in human serum with standard DSF clinical dosing) decreases ER+ breast cancer cell growth (MCF7, T47D and ZR75) in a dose-dependent manner. DSF further sensitizes breast cancer cells to PB or/and LY and significantly inhibits breast cancer growth without causing unwanted side effects on the normal breast epithelial cells. Dose effect and isobologram studies confirm synergistic activity of DSF + LY and moderate synergism for DSF + PB. DSF, alone or in combination with PB (DSF ± PB) and/or LY (DSF ± LY), significantly inhibits expression of MGMT, CDK4/6, ERα and aldehyde dehydrogenase activity - all involved in breast cancer cell cycle proliferation and tumorigenesis. Furthermore, PB and LY dose dependently decreased MGMT and CDK4 expression in breast cancer cells and significantly accumulated breast cancer cells in G1 phase of the cell cycle. DSF, alone or in combination with PB (DSF ± PB) and/or LY (DSF ± LY) caused significant apoptosis in breast cancer cells. DSF inhibited colony formation which was further enhanced by addition of PB/LY (DSF ± PB/LY). Similarly, DSF alone or in combination with PB (DSF ± PB) and/or LY (DSF ± LY) decreased the metastatic potential of breast cancer cells.

Conclusions: Our findings suggest that DSF as an MGMT inhibitor significantly enhances the antitumor effect of CDK4/6 inhibitors (PB or LY) in ER+ breast cancer.

Citation Format: George C. Bobustuc, Amin B. Kassam, Richard A. Rovin, Deborah L. Donohoe, Maxwell Albiero, Tarun Jella, Olivia Fukui, Cameron Piron, Santhi D. Konduri. MGMT inhibition leads to CDK4/6 inhibition and enhances palbociclib and abemaciclib activity in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2035. doi:10.1158/1538-7445.AM2017-2035

Initial experience with a robotically operated video optical telescopic-microscope in cranial neurosurgery: feasibility, safety, and clinical applications

OBJECTIVE

The move toward better, more effective optical visualization in the field of neurosurgery has been a focus of technological innovation. In this study, the authors’ objectives are to describe the feasibility and safety of a new robotic optical platform, namely, the robotically operated video optical telescopic-microscope (ROVOT-m), in cranial microsurgical applications.

METHODS

A prospective database comprising patients who underwent a cranial procedure between April 2015 and September 2016 was queried, and the first 200 patients who met the inclusion criteria were selected as the cohort for a retrospective chart review. Only adults who underwent microsurgical procedures in which the ROVOT-m was used were considered for the study. Preoperative, intraoperative, and postoperative data were retrieved from electronic medical records. The authors address the feasibility and safety of the ROVOT-m by studying various intraoperative variables and by reporting perioperative morbidity and mortality, respectively. To assess the learning curve, cranial procedures were categorized into 6 progressively increasing complexity groups. The main categories of pathology were I) intracerebral hemorrhages (ICHs); II) intraaxial tumors involving noneloquent regions or noncomplex extraaxial tumors; III) intraaxial tumors involving eloquent regions; IV) skull base pathologies; V) intraventricular lesions; and VI) cerebrovascular lesions. In addition, the entire cohort was evenly divided into early and late cohorts.

RESULTS

The patient cohort comprised 104 female (52%) and 96 male (48%) patients with a mean age of 56.7 years. The most common pathological entities encountered were neoplastic lesions (153, 76.5%), followed by ICH (20, 10%). The distribution of cases by complexity categories was 11.5%, 36.5%, 22%, 20%, 3.5%, and 6.5% for Categories I, II, II, IV, V, and VI, respectively. In all 200 cases, the surgical goal was achieved without the need for intraoperative conversion. Overall, the authors encountered 3 (1.5%) major neurological morbidities and 6 (3%) 30-day mortalities. Four of the 6 deaths were in the ICH group, resulting in a 1% mortality rate for the remainder of the cohort when excluding these patients. None of the intraoperative complications were considered to be attributable to the visualization provided by the ROVOT-m. When comparing the early and late cohorts, the authors noticed an increase in the proportion of higher-complexity surgeries (Categories IV–VI), from 23% in the early cohort, to 37% in the late cohort (p = 0.030). In addition, a significant reduction in operating room setup time was demonstrated (p < 0.01).

CONCLUSIONS

The feasibility and safety of the ROVOT-m was demonstrated in a wide range of cranial microsurgical applications. The authors report a gradual increase in case complexity over time, representing an incremental acquisition of experience with this technology. A learning curve of both setup and execution phases should be anticipated by new adopters of the robot system. Further prospective studies are required to address the efficacy of ROVOT-m. This system may play a role in neurosurgery as an integrated platform that is applicable to a variety of cranial procedures.

Establishment and Biological Characterization of a Panel of Glioblastoma Multiforme (GBM) and GBM Variant Oncosphere Cell Lines

Objective

Human tumor cell lines form the basis of the majority of present day laboratory cancer research. These models are vital to studying the molecular biology of tumors and preclinical testing of new therapies. When compared to traditional adherent cell lines, suspension cell lines recapitulate the genetic profiles and histologic features of glioblastoma multiforme (GBM) with higher fidelity. Using a modified neural stem cell culture technique, here we report the characterization of GBM cell lines including GBM variants.

Methods

Tumor tissue samples were obtained intra-operatively and cultured in neural stem cell conditions containing growth factors. Tumor lines were characterized in vitro using differentiation assays followed by immunostaining for lineage-specific markers. In vivo tumor formation was assayed by orthotopic injection in nude mice. Genetic uniqueness was confirmed via short tandem repeat (STR) DNA profiling.

Results

Thirteen oncosphere lines derived from GBM and GBM variants, including a GBM with PNET features and a GBM with oligodendroglioma component, were established. All unique lines showed distinct genetic profiles by STR profiling. The lines assayed demonstrated a range of in vitro growth rates. Multipotency was confirmed using in vitro differentiation. Tumor formation demonstrated histologic features consistent with high grade gliomas, including invasion, necrosis, abnormal vascularization, and high mitotic rate. Xenografts derived from the GBM variants maintained histopathological features of the primary tumors.

Conclusions

We have generated and characterized GBM suspension lines derived from patients with GBMs and GBM variants. These oncosphere cell lines will expand the resources available for preclinical study.

Magnetic resonance imaging fluid-attenuated inversion recovery sequence signal reduction after endoscopic endonasal transcribiform total resection of olfactory groove meningiomas

BACKGROUND

Olfactory groove meningiomas grow insidiously and compress adjacent cerebral structures. Achieving complete removal without further damage to frontal lobes can be difficult. Microsurgical removal of large lesions is a challenging procedure and usually involves some brain retraction. The endoscopic endonasal approaches (EEAs) for tumors arising from the anterior fossa have been well described; however, their effect on the adjacent brain tissue has not. Herein, the authors utilized the magnetic resonance imaging fluid attenuated inversion recovery (FLAIR) sequence signal as a marker for edema and gliosis on pre- and post-operative images of olfactory groove meningiomas, thus presenting an objective parameter for brain injury after surgical manipulation.

METHODS

Imaging of 18 olfactory groove meningiomas removed through EEAs was reviewed. Tumor and pre/postoperative FLAIR signal volumes were assessed utilizing the DICOM image viewer OsiriX(®). Inclusion criteria were: (1) No previous treatment; (2) EEA gross total removal; (3) no further treatment.

RESULTS

There were 14 females and 4 males; the average age was 53.8 years (±8.85 years). Average tumor volume was 24.75 cm(3) (±23.26 cm(3), range 2.8-75.7 cm(3)), average preoperative FLAIR volume 31.17 cm(3) (±39.38 cm(3), range 0-127.5 cm(3)) and average postoperative change volume, 4.16 cm(3) (±6.18 cm(3), range 0-22.2 cm(3)). Average time of postoperative scanning was 6 months (range 0.14-20 months). In all cases (100%) gross total tumor removal was achieved. Nine patients (50%) had no postoperative FLAIR changes. In 2 patients (9%) there was minimal increase of changes postoperatively (2.2 cm(3) and 6 cm(3) respectively); all others demonstrated image improvement. The most common complication was postoperative cerebrospinal fluid leakage (27.8%); 1 patient (5.5%) died due to systemic complications and pulmonary sepsis.

CONCLUSIONS

FLAIR signal changes tend to resolve after endonasal tumor resection and do not seem to worsen with this operative technique.

Flow diversion in the treatment of carotid injury and carotid-cavernous fistula after transsphenoidal surgery

We describe a case of iatrogenic carotid injury with secondary carotid-cavernous fistula (CCF) treated with a silk flow diverter stent placed within the injured internal carotid artery and coils placed within the cavernous sinus. Flow diverters may offer a simple and potentially safe vessel-sparing option in this rare complication of transsphenoidal surgery. The management options are discussed and the relevant literature is reviewed.

Endoscopic endonasal approach for the treatment of schwannomas of the pterygopalatine fossa: case report and review of the literature

INTRODUCTION

Pterygopalatine fossa (PPF) schwannomas are rare lesions most often arising from branches of the trigeminal nerve. Symptomatic lesions have been traditionally treated by conventional external approaches. However, the development of an expanded endonasal approach (EEA) enables skull base surgeons to reach these deeply seated lesions via a different route with its own advantages and drawbacks.

METHODS

Case report and review of the literature.

CASE DESCRIPTION

A 41-year-old woman presented with a 6-year history of right facial pain and numbness. Her symptoms had increased progressively over a year, and she recently had developed right-sided otalgia. MRI revealed a right PPF mass, hypointense on T1 and T2 sequences with homogeneous enhancement following the use of gadolinium. A biopsy, attempted at another institution, was considered non-diagnostic. We totally removed the lesion through an endoscopic endonasal transmaxillary approach. Final pathology confirmed the diagnosis of schwannoma. Post-operatively, the patient noted a significant improvement of her facial pain (V2 territory).

CONCLUSION

The endonasal endoscopic transmaxillary approach provides adequate access to the PPF, thus enabling safe tumor removal with less morbidity than conventional routes.

Diagnostic imaging dilemma of a clival lesion and its clinical management implications

Background A retroclival lesion can represent a notochordal remnant-derived mass. The differential diagnoses includes benign lesions such as ecchordosis physaliphora (EP) and neuroenteric cyst or malignant ones such as chordomas. In the case of EP and chordoma, although both types arise from remnants of fetal notochord tissues, they represent two separate entities with different radiographic and biologic behaviors. Case Description We present a case of an incidental finding of a retroclival lesion. The magnetic resonance imaging (MRI) characteristics of the lesion match the neuroimaging profile of a benign lesion and are suggestive of an EP. There was no enhancement noted with the addition of gadolinium. Nonetheless, pathology determined the lesion to be a malignant chordoma. Conclusion The differential diagnosis of a retroclival lesion includes benign and malignant notochordal lesions. Here we present a case of a patient with an incidental finding of a retroclival lesion. Radiographic findings were suggestive of a benign lesion, possibly EP, yet the pathology revealed a chordoma. This report suggests that despite benign imaging, chordoma cannot be excluded and the implications for treatment can be significant. It is important to achieve the correct diagnosis because the prognostic and therapeutic implications are different.

Avoiding injury to the abducens nerve during expanded endonasal endoscopic surgery: anatomic and clinical case studies

BACKGROUND

Understanding the course of the most medially located parasellar cranial nerve, the abducens, becomes critical when performing an expanded endonasal approach.

OBJECTIVE

We report an anatomoclinical study of the abducens nerve and describe relevant surgical nuances to avoid its injury.

METHODS

Ten anatomic specimens were dissected using endoscopes attached to an high-definition camera. A series of anatomic measurements and relationships of the abducens nerve were noted. Illustrative clinical cases are described to translate those findings into practice.

RESULTS

Cisternal, interdural, gulfar, and cavernous segments of the abducens were identified intracranially. The mean distance from the vertebrobasilar junction (VBJ) to the pontomedullary sulcus (PMS) was 4 mm; horizontal distance between both abducens nerves at the PMS was 10 mm, and between both abducens at the interdural segment was 18.5 mm. The upper limit of the lacerum segment of the internal carotid artery was at the same level of the dural entry point of the sixth cranial nerve posteriorly. The sellar floor at the sphenoid sinus marks the level of the gulfar segment in the craniocaudal axis. At the superior orbital fissure, the abducens nerve and V2 were at an average vertical distance of 11.5 mm.

CONCLUSION

Anatomic landmarks to localize the abducens nerve intraoperatively, such as the VBJ for the transclival approach, the lacerum segment of the carotid, and the sellar floor for the medial petrous apex approach, and V2 for Meckel's cave approach, are reliable and complementary to the use of intraoperative electrophysiological monitoring.

Endoscopic endonasal transpterygoid approaches: anatomical landmarks for planning the surgical corridor

OBJECTIVES/HYPOTHESIS

Endoscopic endonasal transpterygoid approaches (EETA) use the pneumatization of the sinonasal corridor to control lesions of the middle and posterior skull base. These surgical areas are complex and the required surgical corridors are difficult to predict.

AIM

Define anatomical landmarks for the preoperative planning of EETAs.

STUDY DESIGN

Anatomical study.

METHODS

We reviewed images from high-resolution maxillofacial CT scans with (0.6-mm axial slice acquisition). Cephalometric measurements were obtained using Kodak Carestream Image Software (Rochester, NY).

RESULTS

Average distance from midline to the vidian canal was 12.78 mm (range 9.4-15.8 mm). Average horizontal distance from the vidian canal to the foramen rotundum was 5.6 mm (range 2.8-11.5 mm). Average vertical distance from the vidian canal to the foramen rotundum was 6.22 mm (range 4.3-9.3 mm). These landmarks are consequential during the preoperative planning of the surgical corridor. To facilitate communication, we classified EETAs as: A) Partial removal of the pterygoid plates (transposition of temporo-parietal fascia); B) removal of anteromedial aspect of the pterygoid process (lesions involving the lateral recess of the sphenoid sinus); C) involves dissecting the vidian nerve to control the petrous ICA and removing the pterygoid plates base to reach the petrous apex, Meckel's cave, or cavernous sinus; D) variable removal of the pterygoid plates to access the infratemporal fossa; and E) removal of pterygoid process and medial third of the Eustachian tube to expose the nasopharynx.

CONCLUSIONS

Our novel classification and landmarks system helps to understand the anatomy of this complex area and to accurately plan the EETA.

Endoscopic endonasal management of recurrent petrous apex cholesterol granuloma

Introduction Petrous apex cholesterol granulomas (PACGs) are uncommon lesions. Recurrence following transcranial or endonasal approaches to aerate the cyst occurs in up to 60% of cases. We describe the technical nuances pertinent to the endonasal endoscopic management of a recurrent symptomatic PACG and review the literature. Results A 19-year-old woman presented with a recurrent abducens nerve paresis. Four months prior, she underwent an endonasal transsphenoidal surgery (TSS) for drainage of a symptomatic PACG. Current imaging documented recurrence of the right PACG. Transsphenoidal and infrapetrous approaches were performed to obtain a wider bony opening along the petrous apex and drain the cyst. A Doyle splint was inserted into the cyst's cavity and extended out into the sphenoid sinus, maintaining patency during the healing process. Three months after surgery, the splint was removed endoscopically, allowing visualization of a patent cylindrical communication between both aerated cavities. The patient remains symptom-free and recurrence-free. Conclusion Endoscopic endonasal surgery must be adapted to manage a recurrent PACG. A TSS may not be sufficient. An infrapetrous approach with wider bony opening, extensive removal of the cyst's anterior wall, and the use of a stent are indicated for the treatment of recurrent PACG and to prevent recurrences.

Intraoperative neurophysiological monitoring during circulatory arrest using deep hypothermia: A case report during brain aneurysm clipping

Neuroprotection is the main goal during procedures that involve circulatory arrest using hypothermia. This case report describes the role intraoperative neurophysiological monitoring (IONM) plays and describes the sensitivity of specific modalities used intraoperatively to identify changes and intervene in a timely manner Understanding the contributing factors and IONM changes during hypothermia helps the neuroelectrophysiology monitorist and the surgeon to provide optimal care while minimizing morbidity. In this report we describe the role of IONM from the monitorist's perspective, describing the surgical procedure and the sequence of events. This report illustrates the electrophysiological changes that occur during aneurysm clipping during cardiopulmonary arrest with deep hypothermia.

Teamwork in skull base surgery: An avenue for improvement in patient care

BACKGROUND

During the past several decades, numerous centers have acquired significant expertise in the treatment of skull base pathologies. Favorable outcomes are not only due to meticulous surgical planning and execution, but they are also related to the collaborative efforts of multiple disciplines. We review the impact of teamwork on patient care, elaborate on the key processes for successful teamwork, and discuss its challenges.

METHODS

Pubmed and Medline databases were searched for publications from 1970 to 2012 using the following keywords: "teamwork", "multidisciplinary", "interdisciplinary", "surgery", "skull base", "neurosurgery", "tumor", and "outcome".

RESULTS

Current literature testifies to the complexity of establishing and maintaining teamwork. To date, few reports on the impact of teamwork in the management of skull base pathologies have been published. This lack of literature is somewhat surprising given that most patients with skull base pathology receive care from multiple specialists. Common factors for success include a cohesive and well-integrated team structure with well-defined procedural organization. Although a multidisciplinary work force has clear advantages for improving today's quality of care and propelling research efforts for tomorrow's cure, teamwork is not intuitive and requires training, guidance, and executive support.

CONCLUSIONS

Teamwork is recommended to improve quality over the full cycle of care and consequently patient outcomes. Increased recognition of the value of an integrated team approach for skull base pathologies will hopefully encourage centers, physicians, allied health caregivers, and scientists devoted to treating these patients and advancing the field of knowledge to invest the time, effort, and resources to optimize and organize their collective expertise.

Side-cutting aspiration device for endoscopic and microscopic tumor removal

The authors present a unique side-cutting instrument (NICO Myriad, Indianapolis, IN) with variable aspiration designed specifically for tumor resection. The study included retrospective review of data collected from 10/2009 to 01/2011. We detail the use of the Myriad in 31 patients with the following pathologies: meningioma (n=16), chordoma (n = 3), schwannoma (n = 3), pituitary adenoma (n = 2), metastasis (n = 3), hemangioblastoma (n = 1), craniopharyngioma (n = 1), and nasopharyngeal tumors (n = 2). Surgical approaches included expanded endonasal approach (n = 19), endoscopic brain port (n = 3), supraorbital "eyebrow" craniotomy (n = 3), retrosigmoid suboccipital craniotomy (n = 3), pterional craniotomy (n = 1), extreme far lateral (n = 1), and laminectomy (n = 1). Successful tumor resection was achieved in 30 cases. Instrument failure was noted in only one extremely fibrous meningioma. The design of this instrument facilitated maneuvering through narrow corridors while providing direct visualization of the suction aperture during tumor resection. These features allowed for tumor removal without injury to adjacent neurovascular structures. The side-cutting aspiration device allows safe and effective tumor removal. Its low profile, variable aspiration, and lack of thermal heat energy are particularly useful in tumor resection through narrow corridors, such as endonasal, port, and keyhole approaches. The multifunctional nature of the instrument (suction, scissors, and dissectors) minimizes multiple exchanges, facilitating tumor resection through these minimal access corridors.

Comparative analysis of the transcranial "far lateral" and endoscopic endonasal "far medial" approaches: surgical anatomy and clinical illustration

OBJECTIVE

The main aim of our study was to analyze and compare the surgical anatomy pertinent to the dorsal transcranial transcondylar (far lateral approach) with that of the ventral endoscopic endonasal transcondylar (far medial approach) route.

METHODS

Eight cadaveric specimens were dissected and analyzed bilaterally. Brainstem exposure and surgical corridor areas were measured. In addition, we present three clinical scenarios to illustrate the clinical feasibility of the proposed surgical strategies.

RESULTS

The hypoglossal nerve, vertebral artery, and hypoglossal canal divide the lower third of the clivus into ventromedial and dorsolateral compartments. The far medial approach provides significantly larger exposure of the brainstem in the ventromedial compartment (464.6 ± 68.34 mm(2)) compared with the far lateral approach (126.35 ± 32.25 mm(2)), P < 0.01. The far lateral approach provides a wide exposure of the brainstem in the dorsolateral compartment (295.24 ± 58.03 mm(2), 74% of the dorsolateral compartment). The exposure of the brainstem in the dorsolateral compartment is not possible using the endonasal route. The surgical corridor from one compartment to the other, through the lower cranial nerves, was significantly larger on the far lateral approach (78.19 ± 14.54 mm(2)) than on the far medial (23.77 ± 15.17 mm(2)), P = 0.03.

CONCLUSIONS

The far medial approach offers a safe, wide exposure of the lower third of the clivus for lesions that expand ventromedial to the hypoglossal nerve. The far lateral approach is most suitable for lesions located dorsolateral to the lower cranial nerves. The vertebral artery and hypoglossal canal are the most important landmarks to guide surgical planning. A combined endonasal-transcranial approach should be considered for resection of extensive lesions involving both ventromedial and dorsolateral compartments. We strive to encourage skull base surgeons to integrate endoscopic and microscopic approaches to the posterior fossa.

Supraorbital eyebrow craniotomy for removal of intraaxial frontal brain tumors: a technical note

OBJECTIVE

To present the utility and selection criteria for the supraorbital (SO) craniotomy, an approach commonly used to remove extraaxial tumors such as meningiomas and craniopharyngiomas, to resect intraaxial frontal brain lesions.

METHODS

All consecutive patients who underwent a SO craniotomy for an intraaxial lesion were retrospectively analyzed for lesion location, pathology, extent of resection, operative times, length of stay, and complications.

RESULTS

During 28 months, 10 patients (mean age, 67.6 years; 7 women) underwent 11 SO procedures to resect intraaxial brain lesions. Pathologies included metastatic carcinoma (n = 7), glioma (n = 2), and radiation necrosis (n = 1). The mean distance of the shortest trajectory to the lesion was 2.4 mm. Gross total or near-total removal was achieved in 80% of the cases. Median length of hospital stay was 3 days (range, 2-6 days); it was 2 days for patients admitted electively for SO craniotomy. There were no new neurologic deficits, postoperative hematomas, or cerebrospinal fluid leaks.

CONCLUSIONS

The SO "eyebrow" craniotomy is a safe and effective keyhole method to remove intraaxial frontal lobe lesions, particularly lesions of the frontal pole and orbitofrontal region, allowing for minimal disruption of normal brain parenchyma and promoting a rapid recovery and short hospital stay. Metastatic tumors and select gliomas in this area are most amenable to this approach. Deeper intraaxial tumors can also be effectively accessed via this route with excellent clinical outcomes.

Endoscopic endonasal approach for resection of cranial base chordomas: outcomes and learning curve

BACKGROUND

Gross total resection (GTR) of cranial base chordomas represents a surgical challenge because of the location, invasiveness, and tumor extension. In the past decade, the endoscopic endonasal approach (EEA) has been used with notable outcomes.

OBJECTIVE

To present the endoscopic endonasal experience in the treatment of cranial base chordomas at our institution.

METHODS

From April 2003 to March 2011, 60 patients underwent an EEA for primary (n = 35) or previously treated (n = 25) cranial base chordomas. We evaluated the degree of GTR and complications. We studied the factors that influenced outcomes and compared our surgical results in the early and late years of our experience.

RESULTS

The overall rate of GTR of cranial base chordomas was 66.7% (82.9% in primary and 44% in previously treated patients). The most important limitations for GTR were tumor volume greater than 20 cm (P = .042), tumor location in the lower clivus with lateral extension (P = .022), and previously treated disease (P = .002). The learning curve had a significant impact on GTR, increasing the success rate to 88.9% (92.6% in primary patients and 63.6% in previously treated patients) during recent years (P < .0001). The most frequent complication was cerebrospinal fluid leak (20%) resulting in meningitis in 3.3%. Carotid injuries occurred in 2 patients without any resulting deficit. Neurological complications included new cranial neuropathies (6.7%) and long tract deficits (1.7%). There was no operative mortality in our series.

CONCLUSION

For the treatment of cranial base chordomas, the EEA is a competitive alternative to transcranial approaches with minimal morbidity and high success rates of GTR when performed by experienced cranial base surgeons.

Hemostasis management during completely endoscopic removal of a highly vascular intraparenchymal brain tumor: technique assessment

BACKGROUND

Recently, stereotactic-guided removal of intraparenchymal lesions using endoscopic visualization through a brain port has been successfully reported. Although endoneurosurgical tumor resection uses the same principles as those used in microneurosurgery, the ability to control bleeding through the port requires an adapted technique.

MATERIAL AND METHODS

We present a patient that underwent a completely endoscopic resection of a vascular brain tumor through a brain port and describe the hemostatic technique.

RESULTS

A 68 year-old female presented with progressive gait difficulties. She had been previously treated for a breast cancer. Magnetic resonance imaging (MRI) showed a right subcortical solitary cerebellar lesion that homogeneously enhanced. The patient underwent an endoscopic brain port removal of a supposed brain metastasis. After port cannulation, the tumor partly delivered itself into the port. Following initial tumor biopsy, active bleeding occurred. Irrigation and application of Surgifoam allowed to control the bleeding. Coagulation with an adapted bipolar and removal of coagulated tissue with the side-cutting aspiration device were sequentially repeated. Once the tumor was resected, the suction served as counter-traction elongating the vessels whereas the bipolar cauterized them over a long segment. Hemostasis was performed circumferentially along the cavity's walls from deep to superficial, benefiting from the endoscope's dynamic properties and magnification. Pathology confirmed intraoperative suspicion of hemangioblastoma.

CONCLUSION

 Removal of vascular tumors is feasible through the brain port, despite a relatively narrow corridor of 11.5 mm. However, specific hemostasis techniques are required and adapted instruments are needed to ensure hemostasis through these small corridors.

Nasoseptal flap closure of traumatic cerebrospinal fluid leaks

The vascularized nasoseptal flap has become a principal reconstructive technique for the closure of endonasal skull base surgery defects. Despite its potential utility, there has been no report describing the use of the modern nasoseptal flap to repair traumatic cerebrospinal fluid (CSF) leaks and documenting the outcomes of this application. Specific concerns in skull base trauma include septal trauma with disruption of the flap pedicle, multiple leak sites, and issues surrounding persistent leaks after traumatic craniotomy. We performed a retrospective case series review of 14 patients who underwent nasoseptal flap closure of traumatic CSF leaks in a tertiary academic hospital. Main outcome measures include analysis of clinical outcome data. Defect etiology was motor vehicle collision in eight patients (57%), prior sinus surgery in four (29%), and assault in two (14%). At the time of nasoseptal flap repair, four patients had failed prior avascular grafts and two had previously undergone craniotomies for repair. Follow-up data were available for all patients (mean, 10 months). The overall success rate was 100% (no leaks), with 100% defect coverage. The nasoseptal flap is a versatile and reliable local reconstructive technique for ventral base traumatic defects, with a 100% CSF leak repair rate in this series.

Posterior pedicle lateral nasal wall flap: new reconstructive technique for large defects of the skull base

BACKGROUND

Indications for expanded endoscopic approaches continue to grow, resulting in larger and more complex skull base defects. Reconstructive developments, however, have lagged our extirpative capabilities. As the complexity of clinical scenarios continues to escalate, challenging our current reconstructive strategies, we are compelled to develop alternative techniques to prevent cerebrospinal fluid leaks and protect neurovascular structures. In this article we show the anatomic basis for a new posterior pedicled flap from the lateral wall of the nose (Carrau-Hadad [C-H] flap) for the reconstruction of median skull base defects and present our early clinical experience.

METHODS

Using a cadaveric model, we designed a posterior pedicle flap comprising the nasal inferolateral wall mucoperiosteum. We applied this information clinically, to reconstruct transmural skull base defects.

RESULTS

In our cadaveric model, we harvested and transposed C-H flaps into various defects of the planum sphenoidale, sella turcica, clivus, and nasopharynx. Then, we used the C-H flap in four patients, successfully reconstructing their clival (n = 3) and sellar (n = 1) surgical defects. All patients healed uneventfully.

CONCLUSION

Our anatomic study and early clinical experience support the use of the posterior pedicle lateral nasal wall flap to reconstruct large cranial base defects resulting from endoscopic skull base surgery in properly selected patients.

Indications and limitations of endoscopic skull base surgery

A wealth of critical neurovascular structures within a relatively small surface area adds to the already intricate nature of skull base surgery. Surgical approaches to the area are difficult and often associated with significant morbidity and mortality. During the past two decades, endoscopic endonasal approaches (EEAs) have evolved to access the ventral skull base for the resection of tumors (benign and malignant), the decompression of neural structures including the cervicomedullary junction (pannus from rheumatoid arthritis or congenital anomalies, such as platybasia) and the reconstruction of skull base defects (cerebrospinal leaks, meningoencephalocele). These minimal access approaches obviate the need for external incisions, translocation of maxillofacial bones and retraction of the brain. Furthermore, EEAs yield improved visualization, which may reduce complications, and improve quality of life outcomes. Anatomical difficulties (e.g., vascular encasement or extension beyond the plane of a major vessel or cranial nerve), various special conditions (e.g., pediatric patients and vascular tumor) and limitation of institutional resources and technical difficulties may limit the use of EEAs. Thus, one should understand the indications and limitations of EEAs to optimize patient selection, which, in turn, may lead to superior surgical outcomes and reduced morbidity.

Preservation of olfactory function following endoscopic resection of select malignancies of the nasal vault

Preservation of olfactory function during anterior skull base surgery has been previously described. However, its feasibility during oncological resection remains undefined. The aim of this study was to clarify the feasibility of preserving olfactory function in select patients undergoing oncological anterior skull base resection via endonasal endoscopic approach. This is a retrospective case series study. Postoperatively, all patients underwent a standardized smell identification test (Sensonics Inc., Haddon, NJ, USA). From January 2002 to December 2009, we attempted to preserve olfactory function in 9 patients who required an endoscopic resection involving the anterior skull base for treatment of various malignancies presenting unilateral extension. These included: esthesioneuroblastoma (n=6), squamous cell carcinoma (n=1), adenocarcinoma (n=1) and hemangiopericytoma (n=1). In 7 patients, resection included a unilateral endoscopic craniectomy with preservation of the contralateral middle and superior turbinates. Two patients underwent resection of the entire lateral nasal wall and the olfactory epithelium as the superior limit of tumor resection. Six patients received adjuvant radiotherapy. Postoperatively, olfaction was documented in 7 patients (3 normosmic, 4 microsmic). All patients are free of recurrence at the original site at a mean follow-up period of 55.7 months (range 21-101 months). One patient with an esthesioneuroblastoma developed a cervical lymph node recurrence four years after surgery. In selected cases, it is feasible to preserve olfactory function without apparent compromise of oncological outcomes. The success rate depends largely on the extent of the resection, which, in turn, is dictated, by the extent of the tumor.

Microvascular decompression for hemifacial spasm: evaluating outcome prognosticators including the value of intraoperative lateral spread response monitoring and clinical characteristics in 293 patients

Hemifacial spasm is a socially disabling condition that manifests as intermittent involuntary twitching of the eyelid and progresses to muscle contractions of the entire hemiface. Patients receiving microvascular decompression of the facial nerve demonstrate an abnormal lateral spread response (LSR) in peripheral branches during facial electromyography. The authors retrospectively evaluate the prognostic value of preoperative clinical characteristics and the efficacy of intraoperative monitoring in predicting short- and long-term relief after microvascular decompression for hemifacial spasm. Microvascular decompression was performed in 293 patients with hemifacial spasm, and LSR was recorded during intraoperative facial electromyography monitoring. In 259 (87.7%) of the 293 patients, the LSR was attainable. Patient outcome was evaluated on the basis of whether the LSR disappeared or persisted after decompression. The mean follow-up period was 54.5 months (range, 9-102 months). A total of 88.0% of patients experienced immediate postoperative relief of spasm; 90.8% had relief at discharge, and 92.3% had relief at follow-up. Preoperative facial weakness and platysmal spasm correlated with persistent postoperative spasm, with similar trends at follow-up. In 207 patients, the LSR disappeared intraoperatively after decompression (group I), and in the remaining 52 patients, the LSR persisted intraoperatively despite decompression (group II). There was a significant difference in spasm relief between both groups within 24 hours of surgery (94.7% vs. 67.3%) (P < 0.0001) and at discharge (94.2% vs. 76.9%) (P = 0.001), but not at follow-up (93.3% vs. 94.4%) (P = 1.000). Multivariate logistic regression analysis demonstrated independent predictability of residual LSR for present spasm within 24 hours of surgery and at discharge but not at follow-up. Facial electromyography monitoring of the LSR during microvascular decompression is an effective tool in ensuring a complete decompression with long-lasting effects. Although LSR results predict short-term outcomes, long-term outcomes are not as reliant on LSR activity.