Compressive myelopathy from diffuse spinal dural calcifications in a patient with end-stage renal disease: illustrative case

BACKGROUND

Diffuse spinal dural calcification is a rare disorder associated with hyperparathyroidism, including the secondary forms associated with renal failure, osteodystrophy, and chronic hypocalcemia. Here, the authors report a rare case of diffuse dural calcification causing spinal cord compression with myelopathy, requiring decompressive surgery with duraplasty to achieve adequate decompression.

OBSERVATIONS

A 46-year-old male with a history of renal failure on dialysis presented with 2 months of progressive neuropathic pain, lower-extremity weakness, and nonsustained clonus. Spine imaging showed severe renal osteodystrophy with multilevel compression fractures and diffuse dural calcifications with areas of invagination causing severe spinal cord compression. Decompressive surgery was recommended. In surgery, a thickened and calcified dura was encountered with areas of buckling causing spinal cord compression. The invaginated area of the dura was resected and reconstructed with patch duraplasty. The patient's neurological status remained unchanged postoperatively, and at the 6-month follow-up, the patient reported significant improvement in pain and muscle spasms.

LESSONS

Diffuse dural calcifications are a rare complication of prolonged dialysis and secondary hyperparathyroidism. When there is resultant spinal cord compression, this condition requires an intradural approach that addresses the thickened, calcified dura directly to obtain adequate spinal cord decompression.

Augmented Reality Registration System for Visualization of Skull Landmarks

BACKGROUND

Augmented reality (AR) is an emerging technology in neurosurgery with the potential to become a strategic tool in the delivery of care and education for trainees. Advances in technology have demonstrated promising use for improving visualization and spatial awareness of critical neuroanatomic structures. In this report, we employ a novel AR registration system for the visualization and targeting of skull landmarks.

METHODS

A markerless AR system was used to register 3-dimensional reconstructions of suture lines onto the head via a head-mounted display. Participants were required to identify craniometric points with and without AR assistance. Targeting error was measured as the Euclidian distance between the user-defined location and the true craniometric point on the subjects' heads.

RESULTS

All participants successfully registered 3-dimensional reconstructions onto the subjects' heads. Targeting accuracy was significantly improved with AR (3.59 ± 1.29 mm). Across all target points, AR increased accuracy by an average of 19.96 ± 3.80 mm. Posttest surveys revealed that participants felt the technology increased their confidence in identifying landmarks (4.6/5) and that the technology will be useful for clinical care (4.2/5).

CONCLUSIONS

While several areas of improvement and innovation can further enhance the use of AR in neurosurgery, this report demonstrates the feasibility of a markerless headset-based AR system for visualizing craniometric points on the skull. As the technology continues to advance, AR is expected to play an increasingly significant role in neurosurgery, transforming how surgeries are performed and improving patient care.

Detection of diagnostic and prognostic methylation-based signatures in liquid biopsy specimens from patients with meningiomas

Recurrence of meningiomas is unpredictable by current invasive methods based on surgically removed specimens. Identification of patients likely to recur using noninvasive approaches could inform treatment strategy, whether intervention or monitoring. In this study, we analyze the DNA methylation levels in blood (serum and plasma) and tissue samples from 155 meningioma patients, compared to other central nervous system tumor and non-tumor entities. We discover DNA methylation markers unique to meningiomas and use artificial intelligence to create accurate and universal models for identifying and predicting meningioma recurrence, using either blood or tissue samples. Here we show that liquid biopsy is a potential noninvasive and reliable tool for diagnosing and predicting outcomes in meningioma patients. This approach can improve personalized management strategies for these patients.

The Potential Negative Effects of Smoking on Cervical and Lumbar Surgery Beyond Pseudarthrosis: A Michigan Spine Surgery Improvement Collaborative Study

OBJECTIVE

To review the Michigan Spine Surgery Improvement Collaborative registry to investigate the long-term associations between current smoking status and outcomes after elective cervical and lumbar spine surgery.

METHODS

Using the Michigan Spine Surgery Improvement Collaborative, we captured all cases from January 1, 2017, to November 21, 2020, with outcomes data available; 19,251 lumbar cases and 7936 cervical cases were included. Multivariate regression analyses were performed to assess the relationship of smoking with the clinical outcomes.

RESULTS

Current smoking status was associated with lower urinary retention and satisfaction for patients after lumbar surgery and was associated with less likelihood of achieving minimal clinically important difference in primary outcome measures including Patient-Reported Outcomes Measurement Information System, back pain, leg pain, and EuroQol-5D at 90 days and 1 year after surgery. Current smokers were also less likely to return to work at 90 days and 1 year after surgery. Among patients who underwent cervical surgery, current smokers were less likely to have urinary retention and dysphagia postoperatively. They were less likely to be satisfied with the surgery outcome at 1 year. Current smoking was associated with lower likelihood of achieving minimal clinically important difference in Patient-Reported Outcomes Measurement Information System, neck pain, arm pain, and EuroQol-5D at various time points. There was no difference in return-to-work status.

CONCLUSIONS

Our analysis suggests that smoking is negatively associated with functional improvement, patient satisfaction, and return-to-work after elective spine surgery.

Abstract TP53: Geomagnetic Storms Do Not Predict The Occurrence Of LVO Stroke Clusters Necessitating Endovascular Intervention

Intro: Space weather induced geomagnetic storms have been associated with an increased risk of stroke occurrence. Data on image-proven, temporally related large vessel occlusion stroke (LVO) and geomagnetic storms are lacking. We sought to investigate this potential association to determine whether space weather forecasts can be used to predict incoming cluster events.

Methods: Data from a Comprehensive Stroke Center were collected from January 1, 2017, to April 15, 2022. Space weather data were downloaded from the World Data Centre for Geomagnetism, Kyoto homepage (http://wdc.kugi.kyoto-u.ac.jp/kp/index.html#LIST) The indications for mechanical endovascular reperfusion (MER) were in accordance with the Guidelines for the Early Management of Patients With Acute Ischemic Stroke Regarding Endovascular Treatment: A Guideline for Healthcare Professionals From the American Heart Association/American Stroke Association. Univariate binary logistic regression was performed to assess the potential associations between space weather data and LVO MER cases with 48 hour lag effect. Geomagnetic activity was defined by the National Oceanic and Atmospheric Administration’s (NOAA) Space Weather Prediction Centre (SWPC) space weather scales.

Results: Of the 1931 days included in this study, there were 538 (27.86%) days with at least one LVO MER (450 (23.3%) with 1, 81 (4.19%) with 2, and 7 (0.36%) with 3. There were 1784 days without geomagnetic storm activity and 147 days with minor to severe storms. 290 MER cases occurred out 1014 days of minimal activity (28.6%) 133 MER cases out 497 days of unsettled activity (26.76%) 0.91(0.72-116), 78 MER cases out of 273 days of active activity (28.57%) 1.00(0.74-1.34), 25 MER cases out 109 days of minor storm (22.94%) 0.74(0.47-1.19) and 12 MER cases out of the 38 days of moderate to extreme storms (31.58%) 1.15(0.57-2.31) p-value 0.697.

Conclusion: There was no statistically significant association with geomagnetic storms and the occurrence of large vessel stroke interventions taking into consideration a 48 hour lag effect. Comprehensive stroke center readiness is of utmost importance, but space weather forecasts are unlikely to be helpful in predicting LVO stroke cluster events.

SURG-22. STAGED LASER INTERSTITIAL THERAPY (LITT) FOR THE SURGICAL TREATMENT OF INSULAR GLIOMA: A CASE SERIES WITH A NOVEL TREATMENT PARADIGM

BACKGROUND

Insular gliomas pose a significant surgical challenge due to the insula’s delicate surrounding functional and vascular anatomy. Insular gliomas are conventionally treated with open surgical resection augmented by several surgical adjuvants. Despite advancements in technology and surgical techniques, surgical resection of insular gliomas has been associated with frequent and potentially severe morbidity. Laser interstitial thermal therapy (LITT) is a novel, cytoreductive, and less-invasive treatment option for glioma.

OBJECTIVE

We describe the first-ever series of patients with insular glioma treated with staged LITT with or without subsequent craniotomy.

METHODS

A retrospective institutional database identified patients with insular glioma who underwent staged LITT treatments. Clinical, histopathological, and volumetric lesional characteristics were obtained. Procedural characteristics, morbidity, overall survival (OS), and progression-free survival (PFS) were determined.

RESULTS

Between 2019-2022, 11 patients with insular glioma were treated in stages with a total of 21 LITT procedures with or without subsequent craniotomy. Four patients had Diffuse Astrocytoma (IDHmt/TP53+), one Gemistocytic Astrocytoma (IDHmt/TP53+), three Anaplastic Astrocytoma (IDHmt/TP53+), one Anaplastic Oligodendroglioma (IDHmt/1p19q codel), one secondary GBM (IDHmt/TP53+), and one GBM (IDHwt/TP53-). Six patients were treated with LITT alone, while five patients were treated with LITT followed by a craniotomy for complete resection. Patients had a median tumor volume of 31.5 cm3 (9.58, 97) and a mean extent of ablation±resection of 97.68% (S.D. 5.4). At a median follow-up of 12.59 months, patients had a median PFS of 12.88 months and an OS of 14.46 months. No patients had a change in KPS following LITT. Two patients had a decrease in KPS following surgery.

CONCLUSION

We present the first-ever reported series of insular glioma treated with staged LITT with/without subsequent resection. We found that staged treatment of insular gliomas with LITT is safe, effective, and a minimally invasive option that avoids the potentially significant morbidity associated with conventional surgery.

OS01.7.A Detection of methylation-based prognostic signatures in liquid biopsy specimens from patients with meningiomas

Background

Detection of distinct epigenetic biomarkers in circulating cell-free DNA (cfDNA) of liquid biopsy (LB) specimens (e.g. blood) fosters opportunity for prognostication of central nervous system (CNS) tumors and has not been thoroughly explored in patients with meningiomas.

Material and Methods

We profiled the cfDNA methylome (EPIC array) in serum specimens from patients with meningiomas (MNG; n= 63) and harnessed internal and external meningioma tissue methylome data with reported follow up (n=48). To predict recurrence risk (RR), we consolidated a tissue cohort with at least 5 years of follow up and divided them into confirmed recurrence (CR; either reported progressive disease in post-surgical imaging, or additional resections following initial surgery) and confirmed no-recurrence (CNR: no confirmed disease progression w/in at least 5-years of follow-up). Then through application of an iterative process consisting of multiple tissue- and serum-based supervised analyses, we identified risk-specific methylation markers with serum specific features which, when inputted into a random forest algorithm allowed for segregation of both tumor tissue and liquid biopsy specimens according to recurrence risk. We estimated immune cell composition using MethylCIBERSORT, where a reference methylome atlas of chosen immune cell types was utilized to deconvolute the MNG samples.

Results

The resulting recurrence risk classifier demonstrated an appreciable predictive power in classifying samples as high or low recurrence risk across the tumor tissue cohort (ACC: 87.5%, CUI+: 85.2%). When compared to another classifier, our model demonstrated statistically significant agreement across primary meningioma samples (κ=0.269, p=0.002), and more accurately predicted samples to recur across an expanded time window (time to recurrence >5yrs). Across resulting liquid biopsy classifications, recurrence risk subgroups were analogous with reported risk factors, including WHO grade, extent of resection, and tumor location. Recurrence risk subgroups (high and low) also demonstrated differential estimated immune cell contributions, with low-risk samples exhibiting a “hot” profile, or enrichment of B-Cells, CD56- and CD4 T-Cells, and natural killer cells. Notably, the estimated neutrophil to lymphocyte ratio, previously purported to be relevant to tumor prognosis, was appreciably higher for those meningioma samples with the highest recurrence risk.

Conclusion

DNA methylation markers identified in the serum are suitable for the development of machine learning-based models which present high predictive power to prognosticate patients with meningioma and estimate a differential immune profile across recurrence risk groups. After validation in an external cohort, this noninvasive approach may improve the presurgical therapeutic management of patients with meningiomas.

Enterovirus-Induced Severe Rhabdomyolysis and Acute Fulminant Liver Failure in an Immunocompetent Adult Requiring Liver Transplantation: A Case Report

The authors report a case of a young healthy adult with severe rhabdomyolysis and acute fulminant liver failure with multiple organ dysfunction syndromes (MODS), possibly from an enterovirus infection. To the best of our knowledge, this is the first-ever reported case of enterovirus-induced rhabdomyolysis and acute liver failure (ALF) in an immunocompetent adult. It is vital that the treating physician be aware of the association between viral infections, viral myositis, and severe rhabdomyolysis with acute liver failure, which can facilitate the optimal management of such patients. Prompt recognition may provide an opportunity for early interventions, including intravenous immunoglobulin and liver transplantation, if warranted.

Surgical management of Grisel syndrome in the adult patient: illustrative case

BACKGROUND

Grisel syndrome describes an infectious soft tissue process that destabilizes the cervical bony elements and ligamentous complexes. This nontraumatic atlantoaxial rotary subluxation occurs in children primarily. This case illustrates a rare case presentation of an adult with Grisel syndrome: infectious destruction of the right atlantoaxial facet joint caused the occiput-C1 vertebra (head) to rotate rightward with lateral horizontal displacement off the C2 vertebra.

OBSERVATIONS

Because the infection destroyed the C1 bony arch and atlantoaxial facet joints with epidural extension, the rotated head and atlas pulled the brainstem–cervical spinal cord junction against a fixed odontoid process, resulting in a cord contusion. Because of the highly unstable craniocervical junction, the patient presented with torticollis and left upper extremity weakness.

LESSONS

Treatment entailed closed reduction under general anesthesia followed by occipitocervical fusion with an occipital plate, C1 lateral mass screws, and C2-C5 pedicle screws. This case describes the unique surgical pearls necessary for occipitocervical fusion of an unstable craniocervical junction, including tips with neuronavigation, trajectories of the cervical pedicle screws, aligning the lateral mass and pedicle screws with the occipital plate, and nuances with occipitocervical distraction.

A Matched Cohort Analysis of Drain Usage in Elective Anterior Cervical Discectomy and Fusion: A Michigan Spine Surgery Improvement Collaborative (MSSIC) Study

STUDY DESIGN

This is a retrospective, cohort analysis of multi-institutional database.

OBJECTIVE

This study was designed to analyze the impact of drain use following elective anterior cervical discectomy and fusion (ACDF) surgeries.

SUMMARY OF BACKGROUND DATA

After ACDF, a drain is often placed to prevent postoperative hematoma. However, there has been no high quality evidence to support its use with ACDF despite the theoretical benefits and risks of drain placement.

METHODS

The Michigan Spine Surgery Improvement Collaborative database was queried to identify all patients undergoing elective ACDF between February 2014 and October 2019. Cases were divided into two cohorts based on drain use. Propensity-score matching was utilized to adjust for inherent differences between the two cohorts. Measured outcomes included surgical site hematoma, length of stay, surgical site infection, dysphagia, home discharge, readmission within 30 days, and unplanned reoperation.

RESULTS

We identified 7943 patients during the study period. Propensity-score matching yielded 3206 pairs. On univariate analysis of matched cohorts, there were no differences in rate of postoperative hematoma requiring either return to OR or readmission. We noted patients with drains had a higher rate of dysphagia (4.6% vs. 6.3%; P = 0.003) and had longer hospital stay (P < 0.001). On multivariate analysis, drain use was associated with significantly increased length of stay (relative risk 1.23, 95% confidence interval [CI] 1.13-1.34; P < 0.001). There were no significant differences in other outcomes measured.

CONCLUSION

Our analysis demonstrated that drain use is associated with significant longer hospital stay.Level of Evidence: 3.

LMD-21. Headache Improvement Predicts Survival after CSF diversion in Leptomeningeal Disease

Background

Leptomeningeal carcinomatosis (LMD) is a seeding of the leptomeninges by malignant cells. Clinical, treatment and patient-related factors have been described in patients with LMD. Current data are limited by small sample size, particularly in patients undergoing ventriculoperitoneal shunting (VPS) as part of the treatment regimen.

Objective

This study presents the largest cohort of LMD patients in the literature undergoing cerebrospinal fluid (CSF) diversion and seeks to identify prognostic factors related to survival.

Methods

A retrospective review of patients diagnosed with LMD between 2010 and 2016 at a quaternary referral center was performed. Cox proportional hazards modeling was utilized to identify variables associated with improved overall survival from LMD diagnosis. Overall survival was depicted using Kaplan-Meier methodology. Competing risk methodology was used to identify variables associated with VPS, considering death as a competing event.

Results

Of the 314 patients identified, 112 underwent VPS placement. The median overall survival from LMD diagnosis was 3.9 months (95% CI: 3.2–4.4). The presence of headaches, increased opening pressure, and gait difficulty increased the likelihood of VPS placement (all p<0.05). VPS, older age, lower Karnofsky Performance Status (KPS), higher opening pressure and CSF nucleated cell count (NCC) increased the risk of death (all p<0.05). Patients reporting headache improvement after VPS had better survival (p<0.05).

Conclusions

Headache, increased opening pressure and gait instability were associated with higher rate of VPS placement and may portend more aggressive disease. Headache improvement following VPS is a favorable prognostic sign, suggesting survival advantage for patients with hydrocephalus undergoing VPS. Age, KPS, VPS, opening pressure, CSF NCC, concomitant visceral metastases and histology-specific molecular profile impact survival.

SURG-14. Laser Ablation for Brain Metastases: Risk Factors for Neurologic Complication

Introduction

Laser interstitial thermal therapy (LITT) is a routinely used in treatment of recurrent brain metastases following SRS or open craniotomy. While considered safer than craniotomy, patients do experience neurologic decline following LITT. Identifying which patients are at risk for neurologic deterioration can help better advise patients on the most appropriate treatment options for their tumor.

Objective

The objective of the present study was to assess the frequency and identify risk factors for neurologic decline following LITT.

Methods

Data was gathered on patients who underwent LITT for ablation of metastatic brain tumors at our institution between 2014–2019. These cases were analyzed retrospectively and data was collected on patient demographics, tumor characteristics, procedural details, and post-operative complications and outcomes. Pre-operative neurologic function was compared to neurologic status at the 6–12 week post-op visit.

Results

16 patients underwent LITT of a total of 18 metastatic lesions during the study time period and were included in the analysis. 7/16 patients demonstrated reduced KPS or worse neurologic function at 6–12 week follow up. 4 patients (25%) demonstrated neurologic deficits that were attributable to the laser ablation procedure, and each of these 4 patients had lesions in eloquent areas. Comparatively, none of the other 12 patients analyzed had eloquent lesions (p = 0.002). The presence of a pre-op neurologic deficit was not predictive of worsening neurologic function following LITT (p = 0.35). Average lesion size in patients who experienced neurologic deficit was 5.69cm³ compared to 3.15cm³ in those that did not (p = 0.1).

Conclusion

Our complications rate is similar to other published case series (15–44%). LITT, while better tolerated than standard craniotomy, can lead to neurologic decline in patients with brain metastases regardless of lesion size or pre-operative functional status. Eloquence is a significant predictor of neurologic complications following laser ablation.

Reducing Superfluous Opioid Prescribing Practices After Brain Surgery: It Is Time to Talk About Drugs

BACKGROUND

Opioids are prescribed routinely after cranial surgery despite a paucity of evidence regarding the optimal quantity needed. Overprescribing may adversely contribute to opioid abuse, chronic use, and diversion.

OBJECTIVE

To evaluate the effectiveness of a system-wide campaign to reduce opioid prescribing excess while maintaining adequate analgesia.

METHODS

A retrospective cohort study of patients undergoing a craniotomy for tumor resection with home disposition before and after a 2-mo educational intervention was completed. The educational initiative was composed of directed didactic seminars targeting senior staff, residents, and advanced practice providers. Opioid prescribing patterns were then assessed for patients discharged before and after the intervention period.

RESULTS

A total of 203 patients were discharged home following a craniotomy for tumor resection during the study period: 98 who underwent surgery prior to the educational interventions compared to 105 patients treated post-intervention. Following a 2-mo educational period, the quantity of opioids prescribed decreased by 52% (median morphine milligram equivalent per day [interquartile range], 32.1 [16.1, 64.3] vs 15.4 [0, 32.9], P < .001). Refill requests also decreased by 56% (17% vs 8%, P = .027) despite both groups having similar baseline characteristics. There was no increase in pain scores at outpatient follow-up (1.23 vs 0.85, P = .105).

CONCLUSION

A dramatic reduction in opioids prescribed was achieved without affecting refill requests, patient satisfaction, or perceived analgesia. The use of targeted didactic education to safely improve opioid prescribing following intracranial surgery uniquely highlights the ability of simple, evidence-based interventions to impact clinical decision making, lessen potential patient harm, and address national public health concerns.

The influence of sagittal spinopelvic alignment on patient discharge disposition following minimally invasive lumbar interbody fusion

Background

The aim of this study was to investigate the changes to spinopelvic sagittal alignment following minimally invasive (MIS) lumbar interbody fusion, and the influence of such changes on postoperative discharge disposition.

Methods

The Michigan Spine Surgery Improvement Collaborative was queried for all patients who underwent transforaminal lumbar interbody fusion (TLIF)or lateral lumbar interbody fusion (LLIF) procedures for degenerative spine disease. Several spinopelvic sagittal alignment parameters were measured, including sagittal vertical axis (SVA), lumbar lordosis, pelvic tilt, pelvic incidence, and pelvic incidence-lumbar lordosis mismatch. Primary outcome measure-discharge to a rehabilitation facility-was expressed as adjusted odds ratio (ORadj) following a multivariable logistical regression.

Results

Of the 83 patients in the study population, 11 (13.2%) were discharged to a rehabilitation facility. Preoperative SVA was equivalent. Postoperative SVA increased to 8.0 cm in the discharge-to-rehabilitation division versus a decrease to 3.6 cm in the discharge-to-home division (P<0.001). The odds of discharge to a rehabilitation facility increased by 25% for every 1-cm increase in postoperative sagittal balance (OR_adj =1.27, P=0.014). The strongest predictor of discharge to rehabilitation was increasing decade of life (OR_adj =3.13, P=0.201).

Conclusions

Correction of sagittal balance is associated with greater odds of discharge to home. These findings, coupled with the recognized implications of admission to a rehabilitation facility, will emphasize the importance of spine surgeons accounting for SVA into their surgical planning of MIS lumbar interbody fusions.

The Effect of Antithrombotics on Hematoma Expansion in Small- to Moderate-Sized Traumatic Intraparenchymal Hemorrhages

BACKGROUND

Although pre-injury antithrombotic agents, including antiplatelets and anticoagulants, are historically associated with expansion of traumatic intraparenchymal hemorrhage (tIPH), the literature has poorly elucidated the actual risk of hematoma expansion on repeat computed tomography (CT). The objective was to determine the effect of antithrombotic agents on hematoma expansion in tIPH by comparing patients with and without pre-injury antithrombotic medication.

METHODS

The volume of all tIPHs over a 5-year period at an academic Level 1 trauma center was measured retrospectively. The initial tIPH was divided into 3 equally sized quantiles. The third tercile, representing the largest subset of tIPH, was then removed from the study population because these patients reflect a different pathophysiologic mechanism that may require a more acute and aggressive level of care with reversal agents and/or operative management. Per institutional policy, all patients with small- to moderate-sized hemorrhages received a 24-hour stability CT scan. Patients who received reversal agents were excluded.

RESULTS

Of the 105 patients with a tIPH on the initial head CT scan, small- to moderate-sized hemorrhages were <5 cm³. The size of tIPH on initial imaging did not statistically significantly differ between the antithrombotic cohort (0.7 ± 0.1 cm³) and the non-antithrombotic cohort (0.5 ± 0.1 cm³) (P = 0.091). Similarly, the volume of tIPH failed to differ on 24-hour repeat imaging (1.0 ± 0.2 cm³ vs. 0.6 ± 0.1 cm³, respectively, P = 0.172). Following a multiple linear regression, only history of stroke, not antithrombotic medications, predicted increased tIPH on 24-hour repeat imaging.

CONCLUSIONS

In small- to moderate-sized tIPH, withholding antithrombotic agents without reversal may be sufficient.

SURG-13. LASER INTERSTITIAL THERMAL THERAPY FOR RECURRENT GLIOBLASTOMA: A REVIEW OF SURVIVAL OUTCOMES COMPARED TO A MATCHED SURGICAL COHORT

INTRODUCTION

Glioblastoma (GBM) is uniformly associated with a poor prognosis and inevitable recurrence. Management of recurrent GBM remains unclear, with repeat surgery often employed with varying degrees of success. We evaluated the efficacy of Laser Interstitial Thermal Therapy (LITT) for recurrent GBM when compared to a carefully matched cohort of patients treated with repeat surgical resection.

METHODS

A retrospective single-institution database was used to identify patients who underwent LITT or surgical resection of recurrent GBM between 2014-2019. LITT patients were matched with surgical resection patients according to baseline demographics, comorbidities, tumor location, and eloquence. Subgroup analysis matching similar patients for tumor volume was also completed. Overall survival (OS) and progression-free survival (PFS) were the primary endpoints.

RESULTS

A LITT cohort of 20 patients was matched to 50 similar patients who underwent repeat surgical resection. Baseline characteristics were similar between both cohorts apart from tumor volume, which was larger in the surgical cohort (17.5 cc vs. 4.7 cc, p&lt; 0.01). On long-term follow-up, there was no difference in OS (HR, 0.72; 95%CI, 0.36-1.45) or PFS (HR, 0.67; 95%CI, 0.29-1.53) between the LITT and surgical cohorts when controlling for tumor volume. Subgroup analysis of 23 LITT patients matched according to tumor volume with 23 surgical patients with similar clinical characteristics also found no difference in OS (HR, 0.66; 95%CI, 0.33-1.30) or PFS (HR, 0.58; 95%CI, 0.90-1.05) between the cohorts. LITT patients had shorter length of stays (1 vs. 4 days, p&lt; 0.001) and a higher rate of home discharge (84% vs. 67%, p=0.172) compared to the surgical cohort.

CONCLUSION

After matching for demographic, clinical, and tumor characteristics, there was no difference in outcomes between patients undergoing LITT compared to surgical resection for recurrent GBM. LITT patients had similar survival outcomes yet shorter hospital stays and more favorable dispositions, potentially mitigating post-treatment complications.

SURG-17. EFFICACY AND SAFETY OF LASER INTERSTITIAL THERMAL ABLATION IN ELDERLY BRAIN TUMOR PATIENTS

INTRODUCTION

Open craniotomy for tumor carries notable perioperative risks as well as associated prolonged ICU stays. Risks of surgery are increased in elderly patients. In addition, many tumors are not amenable to resection due to their deep or eloquent location. Magnetic resonance-guided laser interstitial thermal ablation (LITT) offers an alternative, minimal-access procedure.

OBJECTIVE

To examine the safety and efficacy of LITT procedures in elderly brain tumor patients.

METHODS

Data was gathered on patients over the age of 65 who underwent MRI-guided LITT for ablation of tumor at our institution between 2014-2019. These cases were analyzed retrospectively and data was collected on patient demographics, tumor characteristics, procedural details, and post-operative complications and outcomes.

RESULTS

19 patients over the age of 65 underwent LITT during the study time period and were included in the analysis. The average age was 70 years (range 65-81), with a median follow up of 7 months. Patients had an average of 3.5 pre-existing medical comorbidities with a mean pre-operative Karnofsky Performance Score (KPS) of 87 (SD = 10.4). 13 patients underwent LITT for primary CNS tumor and 6 for metastatic lesions. The average lesion volume was 3.44 cm3 with approximately one-third in eloquent areas. An average extent of ablation of 98% was achieved (90-100%). 5/19 patients experience at least one post-op complication including 2 venous thromboembolic events and 1 stroke within 30 days. The average length of stay was 2.3 days, and 13/19 patients were discharged home. No patients experienced new permanent neurological deficits and the average post-operative KPS was 83 (SD = 12.4). 9 patients experienced progression of disease after an average of 155 days, and 11 patients were deceased (average survival = 504 days).

CONCLUSION

LITT is well tolerated in appropriately selected elderly patients with short post-operative length of stay and minimal surgical morbidity.

INNV-14. UTILIZATION OF A PATIENT FAMILY ADVISORY COUNCIL TO ADVANCE PATIENT-CENTERED CARE OF BRAIN TUMOR PATIENTS

INTRODUCTION

Developing and advancing patient-centered care within neuro-oncology is an essential element of any tertiary brain tumor center. Patient-centered care of neuro-oncology patients requires a holistic approach that integrates oncologic treatment with social and psychological support.

OBJECTIVE

The aim of this study is to evaluate how a Patient Family Advisory Council can be created within an existing brain tumor center and utilized to improve patient-centered care.

METHODS

Current patients and caregivers were recruited by brain tumor staff to participate in monthly meetings. All participants underwent screening and training by our Patient Education Research Center team. Discussions focused on current and future brain tumor center initiatives, and participants were encouraged to give feedback from the patient perspective. New ideas to improve the patient experience were solicited.

RESULTS

A total of 15 participants (female = 57%) were recruited, including 10 with grade 3 or higher brain tumors. Monthly meetings, in-person or virtual, were held for two years. Utilizing participant feedback, the group updated our 80-page patient handbook that contained a variety of patient-caregiver focused resources. Participants also provided feedback on other brain tumor center initiatives such as development of a magnet featuring key phone numbers, an easily accessible website URL for emergencies, and numerous updates to the external website. Additional discussions involved development of neuro-oncology care pathways as we move to a stand-alone cancer center facility and initiation of OncoSTAT and palliative services in this population.

CONCLUSION

Brain tumor patients require a comprehensive oncologic treatment team as well as a wide variety of support services. A Patient Family Advisory Council is an effective method of advancing patient-centered care and a step toward improving the neuro-oncology patient experience.

SURG-16. PREDICTORS OF LOCAL CONTROL FOLLOWING LASER INTERSTITIAL THERMAL THERAPY FOR GLIAL TUMORS

INTRODUCTION

Laser Interstitial thermal therapy (LITT) is a minimal-access procedure for intracranial tumors that are either refractory to standard treatment paradigms or difficult to access via conventional open surgery.

OBJECTIVE

To evaluate predictors of local disease control following LITT in patients with primary and secondary brain tumors.

METHODS

Single-center retrospective cohort study of all consecutive LITT ablations between 2014 and 2019. Demographic and procedural characteristics analyzed with respect to local disease control at 6 months. Chi-square tests for categorical variables, T-tests/Wilcoxon Rank-Sum tests for continuous variables for parametric and non-parametric data, respectively. Poisson regression models were used to approximate relative risk (RR) with 95% confidence intervals.

RESULTS

A total of 76 patients underwent LITT with a median follow up of 12.3 months; pathology at time of ablation was glioblastoma multiforme (GBM, 36%), WHO grade III primary CNS (24%), low grade CNS (20%), and metastatic lesions (19%) with respective local control rates of 26%, 20%, 29%, and 26%. Pathology of GBM (RR 0.46, 0.21-1.02, p=0.055) and a 5-year increase in age at the time of ablation (RR 0.91, 0.83-0.99, p=0.028) were associated with a lower likelihood of local control at 6 months. Preoperative Karnofsky performance status (KPS) of 100 (RR 2.04, 1.13-3.69, p=0.019) was associated with a higher likelihood of local control. Extent of ablation (EOA) demonstrated a direct relationship with local control; when EOA=100% local control was 59%, with this rate dropping down to 21% when EOA=90%. Tumor location, lesion volume, gender, BMI, ethnicity, or whether there existed multiple foci of disease at the time of ablation had no strong association with local control.

CONCLUSION

Our series demonstrates that preoperative performance status and age were strong predictors of local disease control following LITT. Incomplete ablation and histology of high-grade glioma portended a higher risk of local recurrence.

Occipital fixation techniques and complications

Occipitocervical fusions in the adult population are most commonly indicated for neoplastic tumors invading the craniocervical junction (CCJ), rheumatological deformities compromising the foramen magnum, and traumatic dislocations resulting in occiput-C1 instability. Appropriate preoperative imaging will not only assist in identifying the pathology but also determine a treatment regimen for the diseased junction. A treatment algorithm for craniocervical disease is proposed. Lesions must first be identified as irreducible versus reducible: restore extension and/or distraction of the craniovertebral junction without injuring the neural elements. Irreducible lesions require decompression only, while reducible lesions require an added fusion. Techniques in fusion are broadly divided into external immobilization versus internal fixation. The former entails halo rings and tongs for a prolonged duration. Fixation surgeries vary from wiring to screw fixation of the occiput-C1 segment. Details of the operation as well as potential complications are discussed.

Giant Choroid Plexus Papilloma Resection Utilizing a Transcollation System

BACKGROUND

Large vascular brain tumors pose an exceptional challenge in young children. Choroid plexus papilloma (CPP) is an example of a rare, often large and especially vascular neuroepithelial tumor that most commonly arises in children under 5 yr old. Although patients may be cured by total resection, this tumor poses significant surgical risks and challenges related to intraoperative hemostasis.

OBJECTIVE

To describe our experience using a transcollation system during brain tumor surgery in a child to achieve hemostasis and minimize blood loss while preserving normal brain tissue.

METHODS

A 3-yr-old girl presented following a fall and was found to have a giant CPP growing from the right lateral ventricle. Given the vascularity of the tumor and the low intravascular reserve in a small child, a transcollation device was used to reduce blood loss intraoperatively.

RESULTS

Gross total resection was achieved with approximately 300 mL of blood loss without complications. The patient did well postoperatively. Imaging performed at 3 mo after resection revealed return of normal brain architecture.

CONCLUSION

Transcollation devices appear to be an effective and safe addition to the armamentarium of neurosurgical hemostatic options in intracranial tumor resection in which there is a high risk of intraoperative hemorrhage.

Antidepressant pharmacotherapy and poststroke motor rehabilitation: A review of neurophysiologic mechanisms and clinical relevance

According to the National Stroke Association, stroke is the leading cause of adult disability in the United States, where it is estimated that about 795,000 strokes occur on an annual basis. Minimizing the disability burden of a stroke routinely involves behavioral therapies such as physical and occupational therapy, as well as pharmacologic interventions. The positive effect of antidepressants on functional outcomes for patients with poststroke depression is well known and practiced. In the past 15 years, a growing body of evidence has demonstrated that antidepressant pharmacotherapy and selective serotonin reuptake inhibitors specifically have a role in the functional recovery from strokes even in the nondepressed population. The mechanisms by which antidepressants improve motor recovery following stroke are multifactorial, but it is clear that the process involves augmentation of cerebral blood flow, cortical excitation, and potentiation of neural growth factors all resulting in enhancement of neurogeneration. This review will examine the existing evidence and mechanisms behind antidepressant use for motor recovery in stroke patients and discuss the major human clinical trials that have been conducted surrounding this topic. The evidence clearly suggests that antidepressants have a positive impact on poststroke functional recovery regardless of the presence of depression, and although large-scale randomized, controlled trials are still ongoing, antidepressants are emerging as a promising pharmaceutical means of actively lessening the burden of disability following stroke.

Facet Sparing Foraminal Decompression Using the Flexible Shaver Foraminotomy System: Nerve Safety, Pain Relief, and Patient Satisfaction

Background

A number of surgical options exist for decompressing lumbar foraminal stenosis. Flexible shaver foraminotomy is a recent addition to this armamentarium. While the foraminotomy device has been incorporated into clinical practice, the literature on its safety and efficacy remain limited. We aimed to evaluate nerve safety, pain relief, and patient satisfaction in a series of patients treated with the iO-Flex shaver system (Amendia, Inc., Marietta, Georgia).

Methods

Thirty-one consecutive patients with lumbar foraminal stenosis underwent foraminal decompression using the flexible microblade shaver system at 62 neuroforamina. The shavers were inserted into each foramen using an open hemilaminotomy and fluoroscopic guidance. Nerve mapping via mechanomyography (MMG) was used to ensure nerve safety. Perioperative charts were reviewed to find the incidence of neurologic complications and to quantify pain relief. Average office-based follow-up was 5.3 months. A 3-item questionnaire was administered to assess patient satisfaction during late follow-up, which occurred at an average of 21 months.

Results

No planned iO-Flex foraminotomies were aborted. Neurologic complications included transient dysesthetic pain in 1 patient (3.2%, n = 31), and transient numbness in 3 patients (9.7%, n = 31). There were no motor deficits. The composite nerve complication rate was 12.7%. Preoperative visual analog scale scores decreased from a mean of 7.1 (n = 31, standard deviation [SD] 2.0) to a mean of 3.5 (n = 30, SD 2.5). If asked to repeat their decision to do surgery, 81% of patients would redo the procedure. The rate of patient dissatisfaction was 19%.

Conclusions

Decompression of lumbar foramina using the flexible shaver system and MMG nerve mapping is safe and effective, although the short-term sensory complication with this technique may be higher than previously reported. Patient satisfaction with iO-Flex foraminotomy is comparable to reported satisfaction outcomes for traditional lumbar decompression.

Level of Evidence

4.

Monitoring of progesterone in captive female false killer whales, Pseudorca crassidens

The present study describes progesterone profiles to enhance understanding of general reproductive patterns in three female captive false killer whales and analyzes potential relationships in progesterone concentrations between plasma, salivary, and ocular secretions. Plasma progesterone concentrations reflected ovarian activity for most of the year, with increased concentrations in the spring and summer, indicating that the two adult female false killer whales were spontaneous ovulators and seasonally polyestrus. Elevated progesterone concentrations were determined at intervals, for up to 10 consecutive months, in one female. There were also varying periods of no apparent ovarian activity from 3 to 10 consecutive months. Correlation coefficients between progesterone concentrations in plasma, salivary, and ocular secretions ranged between -0.23 and 0.16. It is concluded that blood collection should not be replaced by salivary or ocular secretion collection for the measurement of progesterone in the false killer whale.

Dolphin hearing: relative sensitivity as a function of point of application of a contact sound source in the jaw and head region

The auditory input area of the dolphin head was investigated in an unrestrained animal trained to beach itself and to accept noninvasive electroencephalograph (EEG) electrodes for the recording of the auditory brain-stem response (ABR). The stimulus was a synthetic dolphin click, transmitted from a piezo-electric transducer and coupled to the skin via a small volume of water. The results conform with earlier experiments on acute preparations that show best auditory sensitivity at the middle of the lower jaw. Minimum latency was found at the rear of the lower jaw. A shaded receiver configuration for the dolphin ear is proposed.

In vivo gene transfer of nitric oxide synthase enhances vasomotor function in carotid arteries from normal and cholesterol-Fed rabbits

BACKGROUND

The vascular endothelium is anatomically intact but functionally abnormal in preatherosclerotic states, and an early deficit in the bioavailability of nitric oxide (NO) or related molecules has been described in both humans and animal models. We hypothesized that the targeted gene transfer of NO synthase (NOS) isoforms might ameliorate or reverse the deficit.

METHODS AND RESULTS

We constructed a recombinant adenovirus, Ad.nNOS, that expresses the neuronal isoform of NOS (nNOS) and used it for in vivo endovascular gene transfer to carotid arteries (CA) from normal and cholesterol-fed rabbits. Vessels were harvested 3 days after gene transfer. In CA from normal rabbits, Ad.nNOS generated high levels of functional nNOS protein predominantly in endothelial cells and increased vascular NOS activity by 3.4-fold relative to sham-infected control CA. Ad.nNOS gene transfer also significantly enhanced endothelium-dependent vascular relaxation to acetylcholine; at 3 micromol/L acetylcholine, Ad.nNOS-treated arteries showed an 86+/-4% reduction in precontracted tension, whereas control CA showed a 47+/-6% reduction in tension. Contraction in response to phenylephrine and relaxation in response to nitroprusside were unaffected in both control and Ad.nNOS-treated CA. To determine the effect of Ad.nNOS in atherosclerotic arteries, 10 male New Zealand White rabbits maintained on a 1% cholesterol diet for 10 to 12 weeks underwent gene transfer according to the same protocol used in normal rabbits. Ad.nNOS-treated arteries showed a 2-fold increase in NADPH-diaphorase staining intensity relative to sham-infected and Ad. betaGal-treated arteries. The CA from cholesterol-fed rabbits showed impaired acetylcholine-induced relaxation, but this abnormality was almost entirely corrected by Ad.nNOS gene transfer.

CONCLUSIONS

In vivo adenovirus-mediated endovascular delivery of nNOS markedly enhances vascular NOS activity and can favorably influence endothelial physiology in the intact and atherosclerotic vessel wall.