Second window indocyanine green localizes CNS lymphoma in real time in the operating room: report of two cases.

Intraoperative distinction of lesional tissue versus normal brain parenchyma can be difficult in neurosurgical oncology procedures. We report the successful, real-time visualization of central nervous system (CNS) lymphoma using the 'Second Window Indocyanine Green' (SWIG) method for two patients who underwent craniotomy for pathology that was determined to be large B cell lymphoma. Indocyanine green (ICG), when administered intravenously the day prior to cranial surgery, is a re-purposed fluorophore that may afford safe, immediate visual confirmation of on-target tissue resection, thereby providing a valuable adjunct to intraoperative navigation and decreasing reliance on frozen pathology analysis. These first reported cases of SWIG for lymphoma in the CNS indicate that further study of fluorophores to improve biopsy targeting and yield is warranted.

Refractory glossopharyngeal neuralgia successfully treated with onabotulinumtoxinA: A case report.

BACKGROUND: Glossopharyngeal neuralgia is a rare but severe and disabling pain condition often caused by vascular compression of the glossopharyngeal nerve. Treatment is similar to that of trigeminal neuralgia, but some patients may be refractory to both medical and surgical approaches. Here we present a case of refractory glossopharyngeal neuralgia that responded well to onabotulinumtoxinA (BTX-A). CASE: We report a case of a 65-year-old man with well-controlled human immunodeficiency virus disease with glossopharyngeal neuralgia symptoms since 2015. He had partial response to medications but was limited by side-effects. He underwent microvascular decompression twice with initial relief both times, but experienced recurrence of attacks 1-3 years after each surgery. He was treated with BTX-A using the chronic migraine PREEMPT protocol (i.e., 31-39 injection sites in head and neck muscles), which led to significant relief of his glossopharyngeal neuralgia pain. CONCLUSIONS: This is the first case to our knowledge of glossopharyngeal neuralgia treated with BTX-A. BTX-A can be an effective treatment for glossopharyngeal neuralgia, even when injections are not administered directly over the sensory distribution of the glossopharyngeal nerve.

Indocyanine green fluorescence-guided surgery in head and neck cancer: A systematic review.

OBJECTIVE: To assess the feasibility and effectiveness of indocyanine green (ICG) for image-guided resection of head and neck cancer (HNC). DATA SOURCES: PubMed, Embase, and Scopus databases. REVIEW METHODS: Searches were conducted from database inception to February 2022. Patient and study characteristics, imaging parameters, and imaging efficacy data were extracted from each study. RESULTS: Nine studies met inclusion criteria, representing 103 head and neck tumors. Weighted mean ICG dose and imaging time were 1.27 mg/kg and 11.77 h, respectively. Among the five studies that provided quantitative metrics of imaging efficacy, average ICG tumor-to-background ratio (TBR) was 1.56 and weighted mean ONM-100 TBR was 3.64. Pooled sensitivity and specificity across the five studies were 91.7 % and 71.9 %, respectively. CONCLUSION: FGS with ICG may facilitate real-time tumor-margin delineation to improve margin clearance rates and progression-free survival. Future studies with validated, quantitative metrics of imaging success are necessary to further evaluate the prognostic benefit of these techniques.

Fluorescence guided surgery for pituitary adenomas.

PURPOSE: Resection of pituitary adenomas presents a number of unique challenges in neuro-oncology. The proximity of these lesions to key vascular and endocrine structures as well as the need to interpret neuronavigation in the context of shifting tumor position increases the complexity of the operation. More recently, substantial advances in fluorescence-guided surgery have been demonstrated to facilitate the identification of numerous tumor types and result in increased rates of complete resection and overall survival. METHODS: A review of the literature was performed, and data regarding the mechanism of the fluorescence agents, their administration, and intraoperative tumor visualization were extracted. Both in vitro and in vivo studies were assessed. The application of these agents to pituitary tumors, their advantages and limitations, as well as future directions are presented here. RESULTS: Numerous laboratory and clinical studies have described the use of 5-ALA, fluorescein, indocyanine green, and OTL38 in pituitary lesions. All of these drugs have been demonstrated to accumulate in tumor cells. Several studies have reported the successful use of the majority of the agents in inducing intraoperative tumor fluorescence. However, their sensitivity and specificity varies across the literature and between functioning and non-functioning adenomas. CONCLUSIONS: At present, numerous studies have shown the feasibility and safety of these agents for pituitary adenomas. However, further research is needed to assess the applicability of fluorescence-guided surgery across different tumor subtypes as well as explore the relationship between their use and postoperative clinical outcomes.

Applications of indocyanine green in brain tumor surgery: review of clinical evidence and emerging technologies.

Indocyanine green (ICG) is a water-soluble dye that was approved by the FDA for biomedical purposes in 1956. Initially used to measure cardiocirculatory and hepatic functions, ICG's fluorescent properties in the near-infrared (NIR) spectrum soon led to its application in ophthalmic angiography. In the early 2000s, ICG was formally introduced in neurosurgery as an angiographic tool. In 2016, the authors' group pioneered a novel technique with ICG named second-window ICG (SWIG), which involves infusion of a high dose of ICG (5.0 mg/kg) in patients 24 hours prior to surgery. To date, applications of SWIG have been reported in patients with high-grade gliomas, meningiomas, brain metastases, pituitary adenomas, craniopharyngiomas, chordomas, and pinealomas.The applications of ICG have clearly expanded rapidly across different specialties since its initial development. As an NIR fluorophore, ICG has advantages over other FDA-approved fluorophores, all of which are currently in the visible-light spectrum, because of NIR fluorescence's increased tissue penetration and decreased autofluorescence. Recently, interest in the latest applications of ICG in brain tumor surgery has grown beyond its role as an NIR fluorophore, extending into shortwave infrared imaging and integration into nanotechnology. This review aims to summarize reported clinical studies on ICG fluorescence-guided surgery of intracranial tumors, as well as to provide an overview of the literature on emerging technologies related to the utility of ICG in neuro-oncological surgeries, including the following aspects: 1) ICG fluorescence in the NIR-II window; 2) ICG for photoacoustic imaging; and 3) ICG nanoparticles for combined diagnostic imaging and therapy (theranostic) applications.

Intraoperative real-time near-infrared optical imaging for the identification of metastatic brain tumors via microscope and exoscope.

OBJECTIVE: As chemotherapy and radiotherapy have developed, the role of a neurosurgeon in the treatment of metastatic brain tumors is gradually changing. Real-time intraoperative visualization of brain tumors by near-infrared spectroscopy (NIRS) is feasible. The authors aimed to perform real-time intraoperative visualization of the metastatic tumor in brain surgery using second-window indocyanine green (SWIG) with microscope and exoscope systems. METHODS: Ten patients with intraparenchymal brain metastatic tumors were administered 5 mg/kg indocyanine green (ICG) 1 day before the surgery. In some patients, a microscope was used to help identify the metastases, whereas in the others, an exoscope was used. RESULTS: NIRS with the exoscope and microscope revealed the tumor location from the brain surface and the tumor itself in all 10 patients. The NIR signal could be detected though the normal brain parenchyma up to 20 mm. While the mean signal-to-background ratio (SBR) from the brain surface was 1.82 ± 1.30, it was 3.35 ± 1.76 from the tumor. The SBR of the tumor (p = 0.030) and the ratio of Gd-enhanced T1 tumor signal to normal brain (T1BR) (p = 0.0040) were significantly correlated with the tumor diameter. The SBR of the tumor was also correlated with the T1BR (p = 0.0020). The tumor was completely removed in 9 of the 10 patients, as confirmed by postoperative Gd-enhanced MRI. This was concomitant with the absence of NIR fluorescence at the end of surgery. CONCLUSIONS: SWIG reveals the metastatic tumor location from the brain surface with both the microscope and exoscope systems. The Gd-enhanced T1 tumor signal may predict the NIR signal of the metastatic tumor, thus facilitating tumor resection.

Combined fluorescence-guided surgery and photodynamic therapy for glioblastoma multiforme using cyanine and chlorin nanocluster.

INTRODUCTION: Glioblastoma multiforme (GBM) is the most common primary intracranial malignancy; survival can be improved by maximizing the extent-of-resection. METHODS: A near-infrared fluorophore (Indocyanine-Green, ICG) was combined with a photosensitizer (Chlorin-e6, Ce6) on the surface of superparamagnetic-iron-oxide-nanoparticles (SPIONs), all FDA-approved for clinical use, yielding a nanocluster (ICS) using a microemulsion. The physical-chemical properties of the ICS were systematically evaluated. Efficacy of photodynamic therapy (PDT) was evaluated in vitro with GL261 cells and in vivo in a subtotal resection trial using a syngeneic flank tumor model. NIR imaging properties of ICS were evaluated in both a flank and an intracranial GBM model. RESULTS: ICS demonstrated high ICG and Ce6 encapsulation efficiency, high payload capacity, and chemical stability in physiologic conditions. In vitro cell studies demonstrated significant PDT-induced cytotoxicity using ICS. Preclinical animal studies demonstrated that the nanoclusters can be detected through NIR imaging in both flank and intracranial GBM tumors (ex: 745 nm, em: 800 nm; mean signal-to-background 8.5 ± 0.6). In the flank residual tumor PDT trial, subjects treated with PDT demonstrated significantly enhanced local control of recurrent neoplasm starting on postoperative day 8 (23.1 mm3 vs 150.5 mm3, p = 0.045), and the treatment effect amplified to final mean volumes of 220.4 mm3 vs 806.1 mm3 on day 23 (p = 0.0055). CONCLUSION: A multimodal theragnostic agent comprised solely of FDA-approved components was developed to couple optical imaging and PDT. The findings demonstrated evidence for the potential theragnostic benefit of ICS in surgical oncology that is conducive to clinical integration.

Risk of Brain Arteriovenous Malformation Hemorrhage Before and After Stereotactic Radiosurgery.

Background and Purpose- Understanding the hemorrhage risks associated with brain arteriovenous malformations (AVMs) before and after stereotactic radiosurgery (SRS) is important. The aims of this multicenter, retrospective cohort study are to evaluate and compare the rates of pre- and post-SRS AVM hemorrhage and identify risk factors. Methods- We pooled AVM SRS data from 8 institutions participating in the International Radiosurgery Research Foundation. Predictors of post-SRS hemorrhage were determined using a multivariate logistic regression model. Pre- and post-SRS hemorrhage rates were compared using Fisher exact test. Ruptured and unruptured AVMs were matched in a 1:1 ratio using propensity scores, and their outcomes were compared. Results- The study cohort comprised 2320 AVM patients who underwent SRS. Deep AVM location (odds ratio, 1.86; 95% CI, 1.19-2.92; P=0.007), the presence of an AVM-associated arterial aneurysm (odds ratio, 2.44; 95% CI, 1.63-3.66; P<0.001), and lower SRS margin dose (odds ratio, 0.93; 95% CI, 0.88-0.98; P=0.005) were independent predictors of post-SRS hemorrhage. The post-SRS hemorrhage rate was lower for obliterated versus patent AVMs (6.0 versus 22.3 hemorrhages/1000 person-years; P<0.001). The AVM hemorrhage rate decreased from 15.4 hemorrhages/1000 person-years before SRS to 11.9 after SRS ( P=0.001). The outcomes of the matched ruptured versus unruptured AVM cohorts were similar. Conclusions- SRS appears to reduce the risk of AVM hemorrhage, although this effect is predominantly driven by obliteration. Deep-seated AVMs are more likely to rupture during the latency period after SRS. AVM-associated aneurysms should be considered for selective occlusion before SRS of the nidus to ameliorate the post-SRS hemorrhage rate of these lesions.

A prospective clinical trial of proton therapy for chordoma and chondrosarcoma: Feasibility assessment.

BACKGROUND/OBJECTIVES: Proton therapy (PRT) has emerged as a treatment option for chordomas/chondrosarcomas to escalate radiation dose more safely. We report results of a phase I/II trial of PRT in patients with chordoma/chondrosarcoma. METHODS: Twenty adult patients with pathologically confirmed, nonmetastatic chordoma or chondrosarcoma were enrolled in a single-institution prospective trial of PRT from 2010 to 2014. Seventeen patients received adjuvant PRT and three received definitive PRT. Median dose was 73.8 Gy(RBE; range 68.4-79.2 Gy) using PRT-only (n = 6) or combination PRT/intensity-modulated radiotherapy (IMRT) (n = 14). Quality-of-life (QOL) and fatigue were assessed weekly and every 3 months posttreatment with the Functional Assessment of Cancer Therapy - Brain (FACTBr) and Brief Fatigue Inventory. Primary endpoint was feasibility (90% completing treatment with < 10 day treatment delay and ≤ 20% unexpected acute grade ≥ 3 toxicity). RESULTS: Tumors included chordomas of the skull base (n = 10), sacrum (n = 5), and cervical spine (n = 3), and skull base chondrosarcomas (n = 2). Median age was 57. The 80% had positive margins/gross disease. Median follow-up was 37 months. Feasibility endpoints were met. The 3-year local control and progression-free survival was 86% and 81%. There were no deaths. Two patients had acute grade 3 toxicity (both fatigue). One had late grade 3 toxicity (epistaxis and osteoradionecrosis). There were no significant differences in patient reported fatigue or QOL from baseline to the end-of-treatment. CONCLUSIONS: We report favorable local control, survival, and toxicity following PRT.

Near-infrared intraoperative molecular imaging with conventional neurosurgical microscope can be improved with narrow band "boost" excitation.

BACKGROUND: Intraoperative visualization of brain tumors with near-infrared (NIR)-fluorescent dyes is an emerging method for tumor margin approximation but are limited by existing fluorescence detection platforms. We previously showed that a dedicated NIR imaging platform outperformed a state-of-the-art neurosurgical microscope in fluorescence signal characteristics. This study examined whether conventional neurosurgical microscope NIR signal could be improved with the addition of a narrow wavelength excitation source. METHODS: Imaging was conducted with a broad-spectrum neurosurgical microscope and commercial near-infrared module. Addition of an 805-nm laser was used to "boost" NIR excitation of indocyanine green (ICG). In vitro quantification was performed on serial dilutions of ICG. Patients underwent tumor resection with delayed 24-h imaging of ICG infusion. NIR fluorescence of dura, cortex, or tumor was quantified from images prior to (pre-boost) and following added excitation with the laser (post-boost). Signal to background ratio (SBR) of pre- and post-boost was calculated as a readout of image enhancement. RESULTS: In vitro, excitation boost effected a 29% increase in mean SBR in six serial dilutions of ICG. Intraoperative boost was performed in 11 patients including meningioma, glioblastoma multiforme, and metastases. Increase in tumor fluorescence was pronounced under direct tumor visualization. Across all patients, boost excitation resulted in 35% mean improvement from pre-boost SBR (p < 0.001). CONCLUSION: Neurosurgical microscopes remain the preferred method of visualizing tumor during intracranial surgery. However, current modalities for NIR signal detection are suboptimal. We demonstrate that augmentation of a fluorescence microscope module with a focused excitation source is a simple mechanism of improving NIR tumor visualization. CLINICAL TRIAL REGISTRATION: NCT03262636.

Non-invasive detection of 2-hydroxyglutarate in IDH-mutated gliomas using two-dimensional localized correlation spectroscopy (2D L-COSY) at 7 Tesla.

BACKGROUND: Mutations in the isocitrate dehydrogenase enzyme are present in a majority of lower-grade gliomas and secondary glioblastomas. This mis-sense mutation results in the neomorphic reduction of isocitrate dehydrogenase resulting in an accumulation of the "oncometabolite" 2-hydroxyglutarate (2HG). Detection of 2HG can thus serve as a surrogate biomarker for these mutations, with significant translational implications including improved prognostication. Two dimensional localized correlated spectroscopy (2D L-COSY) at 7T is a highly-sensitive non-invasive technique for assessing brain metabolism. This study aims to assess tumor metabolism using 2D L-COSY at 7T for the detection of 2HG in IDH-mutant gliomas. METHODS: Nine treatment-naïve patients with suspected intracranial neoplasms were scanned at 7T MRI/MRS scanner using the 2D L-COSY technique. 2D-spectral processing and analyses were performed using a MATLAB-based reconstruction algorithm. Cross and diagonal peak volumes were quantified in the 2D L-COSY spectra and normalized with respect to the creatine peak at 3.0 ppm and quantified data were compared with previously-published data from six normal subjects. Detection of 2HG was validated using findings from immunohistochemical (IHC) staining in patients who subsequently underwent surgical resection. RESULTS: 2HG was detected in both of the IDH-mutated gliomas (grade III Anaplastic Astrocytoma and grade II Diffuse Astrocytoma) and was absent in IDH wild-type gliomas and in a patient with breast cancer metastases. 2D L-COSY was also able to resolve complex and overlapping resonances including phosphocholine (PC) from glycerophosphocholine (GPC), lactate (Lac) from lipids and glutamate (Glu) from glutamine (Gln). CONCLUSIONS: This study demonstrates the ability of 2D L-COSY to unambiguously detect 2HG in addition to other neuro metabolites. These findings may aid in establishing 2HG as a biomarker of malignant progression as well as for disease monitoring in IDH-mutated gliomas.

Post-radiosurgical edema associated with parasagittal and parafalcine meningiomas: a multicenter study.

Stereotactic radiosurgery (SRS) offers a high degree of tumor control for benign meningiomas. However, radiosurgery can occasionally incite edema or exacerbate pre-existing peri-tumoral edema. The current study investigates the incidence, timing, and extent of edema around parasagittal or parafalcine meningiomas following SRS. A retrospective multicenter review was undertaken through participating centers in the International Gamma Knife Research Foundation (previously the North American Gamma Knife Consortium or NAGKC). All included patients had a parafalcine or parasagittal meningioma and a minimum of 6 months follow up. The median follow up was 19.6 months (6-158 months). Extent of new or worsening edema was quantitatively analyzed using volumetric analysis; edema indices were longitudinally computed following radiosurgery. Analysis was performed to identify prognostic factors for new or worsening edema. A cohort of 212 patients comprised of 51.9 % (n = 110) females, 40.1 % upfront SRS and 59.9 % underwent adjuvant SRS for post-surgical residual tumor. The median tumor volume at SRS was 5.2 ml. Venous sinus compression or invasion was demonstrated in 25 % (n = 53). The median marginal dose was 14 Gy (8-20 Gy). Tumor volume control was determined in 77.4 % (n = 164 out of 212 patients). Tumor edema progressed and then regressed in 33 % (n = 70), was stable or regressed in 52.8 % (n = 112), and progressively worsened in 5.2 % (n = 11). Tumor location, tumor volume, venous sinus invasion, margin, and maximal dose were found to be significantly related to post-SRS edema in multivariate analysis. SRS affords a high degree of tumor control for patients with parasagittal or parafalcine meningiomas. Nevertheless, SRS can lead to worsening peritumoral edema in a subset of patients such as those with larger tumors (>10 cc) and venous sinus invasion/compression. Long-term follow up is required to detect and appropriately manage post-SRS edema.

Contemporary neurosurgical techniques for pituitary tumor resection.

Approximately 5,000 trans-sphenoidal surgeries are performed for resection of pituitary tumors each year in the United States. The rise in popularity of the trans-spehnoidal approach, though described nearly a century ago, has been facilitated over the last decades by advances in technique and technology. In this review, we discuss the relative strengths of microscopic and endoscopic techniques for pituitary tumor resection. However, despite being the standard of care for patients with most pituitary tumors, cure rates for many subtypes of pituitary lesions, such as secretory macroadenomas or tumors with significant cavernous sinus invasion, remain unsatisfactory. We also describe two more recent advances in neurosurgical technique which may offer promise of increased rates of surgical cure: pseudocapsular resection and cavernous sinus approaches.

Stereotactic radiosurgery of petroclival meningiomas: a multicenter study.

Petroclival meningiomas are difficult to treat due to their intimate location with critical structures, and complete microsurgical resection is often associated with significant morbidity. In this study, we evaluate the outcomes of petroclival meningiomas treated with Gamma Knife radiosurgery (GKRS) as an adjunct to microsurgery or a primary treatment modality. A multicenter study of 254 patients with a benign petroclival meningioma was conducted through the North American Gamma Knife Consortium. One hundred and forty patients were treated with upfront radiosurgery, and 114 following surgery. Multivariate analysis was used to determine predictors of favorable defined as no tumor progression following radiosurgery and the absence of any new or worsening neurological function. At mean follow up of 71 months (range 6-252), tumor volumes increased in 9 % of tumors, remained stable in 52 %, and decreased in 39 %. Kaplan-Meier actuarial progression free survival rates at 3, 5, 8, 10, and 12 years were 97, 93, 87, 84, and 80 % respectively. At last clinical follow-up, 93.6 % of patients demonstrated no change or improvement in their neurological condition whereas 6.4 % of patients experienced progression of symptoms. Favorable outcome was achieved in 87 % of patients and multivariate predictors of favorable outcome included smaller tumor volume (OR = 0.92; 95 % CI 0.87-0.97, p = 0.003), female gender (OR 0.37; 95 % CI 0.15-0.89, p = 0.027), no prior radiotherapy (OR 0.03; 95 % CI 0.01-0.36, p = 0.006), and decreasing maximal dose (OR 0.92; 95 % CI 0.96-0.98, p = 0.010). GKRS of petroclival meningiomas achieves neurological preservation in most patients and with a high rate of tumor control.

Fully endoscopic microvascular decompression for trigeminal neuralgia: technique review and early outcomes.

OBJECT: Fully endoscopicmicrovascular decompression (E-MVD) of the trigeminal nerve was initially described more than 1 decade ago, but has not yet gained wide acceptance. The authors present the experience of their first 47 consecutive E-MVDs for trigeminal neuralgia (TN). METHODS: All surgeries were performed by a single surgeon (J.Y.K.L.) at the Pennsylvania Hospital at the University of Pennsylvania. Patients prospectively completed pain scales before and after surgery by using the Brief Pain Inventory-Facial outcomes tool. All patients were called on the telephone, and the same outcome tool was administered without reference to their preoperative pain status. RESULTS: Forty-seven patients (17 men) were identified and enrolled. Forty (85%) had Burchiel Type 1 TN. Vascular compression was observed at surgery in 42 patients (89%). No surgery was aborted or converted to microscope. One patient suffered permanent hearing loss, for a permanent neurological morbidity rate of 2%. Overall improvement in pain outcomes was excellent, with a median maximum pain intensity preoperatively of 10 and postoperatively of 0 (p< 0.0001). The mean interference with global function scores were 6.2 preoperatively and reduced to 1.0 at last follow-up (p < 0.0001). The mean interference with facial function was 7.3 preoperatively and reduced to 1.2 at last follow-up (p < 0.0001). The mean follow-up period after surgery was 15 ± 8 months. CONCLUSIONS: In experienced hands, E-MVD offers superb visualization and illumination and is both safe and effective, at least in the short term. Further longer-term study is needed to compare E-MVD to traditional microscopic MVD.

Intraoperative visualization of cranial nerve schwannomas using second-window indocyanine green: A case series.

BACKGROUND: Second Window Indocyanine Green (SWIG) is a novel intraoperative imaging technique that uses near-infrared (NIR) light for intra-operative tumor visualization using the well-known fluorophore indocyanine green (ICG). Because schwannomas often incorporate the nerve into the encapsulated tumor and impinge on surrounding neural structures, SWIG is a promising technique to improve tumor resection while sparing the nerve. OBJECTIVE: To demonstrate the use of SWIG in resection of cranial nerve schwannomas. METHODS: Three patients with cranial nerve schwannomas (i.e., trigeminal, vestibular, and vagus) underwent SWIG-guided resection. During surgery, NIR visualization was used intermittently used to detect fluorescence to guide resection. Signal-to-background ratio was then calculated to quantify fluorescence. RESULTS: Patients were infused with ICG at a dose of 5.0 mg/kg 24 hours before surgery. Each patient achieved total or near-total resection and relief of symptoms with lack of recurrence at six-month follow-up. The average SBR calculated was 3.79, comparable to values for SWIG-guided resection of other brain and spine tumors. CONCLUSION: This case series is the first published report of trigeminal and vagus nerve schwannoma resection using the SWIG technique and suggests that SWIG may be used to detect all schwannomas, alongside many other types of brain tumor. This paper also demonstrates the importance of preoperative ICG infusion timing and discusses the inverse pattern of NIR signal that may be observed when infusion occurs outside of the optimal timing. This provides direction for future studies investigating the administration of SWIG to resect cranial nerve schwannomas and other brain tumors.

Dose optimization of second window indocyanine green in meningioma patients.

OBJECTIVE: Surgery remains the first line treatment for meningiomas and can benefit from fluorescence-guided surgical techniques such as second-window indocyanine green (SWIG). In the current study, we compared the use of the standard SWIG dose of 5.0 mg/kg relative to 2.5 mg/kg indocyanine green (ICG) in meningioma patients. METHODS: Patients were prospectively enrolled in an IRB-approved study of SWIG and received either the standard dose of 5.0 mg/kg or a reduced dose of 2.5 mg/kg of ICG around 24 h prior to their surgery. Intraoperative near-infrared fluorescence imaging was performed with exo- and endoscopic systems. Signal-to-background ratio (SBR) was calculated to quantify fluorescence and was compared between 5.0 mg/kg and 2.5 mg/kg ICG. All patients received pre-operative MRI and, in select cases, the pre-operative MRI was correlated to intraoperative fluorescence imaging. RESULTS/DISCUSSION: In the current study, we found no significant difference in the SBR of meningiomas in patients that were administered with either 5.0 mg/kg or 2.5 mg/kg ICG. However, in five patients that received the standard-dose SWIG regimen of 5.0 mg/kg ICG we observed dose-related fluorescence quenching - referred to as "inversion" - that interfered with tumor visualization during fluorescence-guided surgery (FGS). When correlated to pre-operative MRI, a similar rim pattern was observed around the primary tumor on T2 FLAIR, which, in retrospect, could be used as a predictor for inversion during FGS in meningioma patients receiving standard-dose ICG. CONCLUSION: This study demonstrated that a reduced ICG dose was as effective as standard-dose SWIG in meningioma patients. We therefore recommend to adjust the standard ICG dose for meningioma patients to 2.5 mg/kg particularly when rim enhancement is observed on pre-operative T2 FLAIR.

A surgical decision aid for occipital neuralgia with literature review and single center case series.

BACKGROUND: Occipital neuralgia (ON) is a debilitating headache disorder. Due to the rarity of this disorder and lack of high-level evidence, a clear framework for choosing the optimal surgical approach for medically refractory ON incorporating shared decision making with patients does not exist. METHODS: A literature review of studies reporting pain outcomes of patients who underwent surgical treatment for ON was performed, as well as a retrospective chart review of patients who underwent surgery for ON within our institution. RESULTS: Thirty-two articles met the inclusion criteria. A majority of the articles were retrospective case series (22/32). The mean number of patients across the studies was 34 (standard deviation (SD) 39). Among the 13 studies that reported change in pain score on 10-point scales, a study of 20 patients who had undergone C2 and/or C3 ganglionectomies reported the greatest reduction in pain intensity after surgery. The studies evaluating percutaneous ablative methods including radiofrequency ablation and cryoablation showed the smallest reduction in pain scores overall. At our institution from 2014 to 2023, 11 patients received surgical treatment for ON with a mean follow-up of 187 days (SD 426). CONCLUSION: Based on these results, the first decision aid for selecting a surgical approach to medically refractory ON is presented. The algorithm prioritizes nerve sparing followed by non-nerve sparing techniques with the incorporation of patient preference. Shared decision making is critical in the treatment of ON given the lack of clear scientific evidence regarding the superiority of a particular surgical method.

Multi-institutional Analysis of Endoscopic Sellar Surgical Volumes During the COVID-19 Pandemic.

OBJECTIVE: We sought to quantify trends in operative volumes and complications of endoscopic sellar surgery before and after the COVID-19 pandemic onset. STUDY DESIGN: We performed a retrospective analysis. SETTING: TriNetX database analysis. METHODS: All adults undergoing neuroendoscopy for resection of pituitary tumor (Current Procedural Terminology code 62165) with diagnosis of benign/malignant neoplasm of pituitary gland (D35.2/C75.1) or benign/malignant neoplasm of craniopharyngeal duct (D35.3/C75.2) were included using the TriNetX database for 2 years before (pre-COVID group) and 2 years after (post-COVID group) February 17, 2020. RESULTS: A total of 1238 patients in the pre-COVID group and 1186 patients in the post-COVID group were compared. Age, gender, and race were statistically similar between the groups (P > .05). Surgical volume decreased by 6% in the post-COVID group. In 2020 Q2, operative volume decreased by 19%, and in 2021 Q4 (peak COVID-19 caseload in the United States), operative volumes decreased by 29% compared to 2 years prior. Postoperative complications including meningitis (P = .49), cerebrospinal fluid leak (P = .36), visual field deficits (P = .07), postoperative pneumonia or respiratory failure (P = .42), and 30-day readmission rates (P = .89) were similar between the 2 groups. CONCLUSION: Overall, endoscopic sellar surgery may continue to fluctuate with increased COVID-19 outbreaks. Patient outcomes do not appear to be worsened by decreased operative volumes or delays in nonurgent surgeries.