Clear cell histology portends a worse prognosis than other WHO grade II histologies.

PURPOSE: Clear cell meningioma (CCM) is a rare WHO grade II meningioma variant, characterized by aggressive features and a high tumor recurrence rate. In this study, we compared overall and progression-free survivals between CCMs and other WHO grade II meningiomas. METHODS: A retrospective institutional database review was performed to identify all patients who underwent surgical resection of a WHO grade II meningioma between 1997 and 2019. Overall survival and progression-free survival were compared between patients with clear cell meningiomas and patients with other WHO grade II meningiomas. Multivariable Cox proportional-hazards analysis was used to identify independent predictors of tumor recurrence and survival. RESULTS: We included a total of 214 patients in this study (43 CCMs, 171 other WHO grade II meningiomas). Patients with CCMs had significantly shorter progression-free (p = 0.001) and overall (p = 0.026) survivals than patients with other grade II meningiomas. In multivariable analysis, clear cell histology was a significant and powerful independent predictor of tumor recurrence (HR 1.93; 95% CI 1.14-3.26) when controlling for tumor location, extent of resection, and adjuvant radiation. In multivariable analysis, clear cell histology correlated with increased mortality (HR 1.96, 95% CI 0.97-3.94), though this was not statistically significant. CONCLUSION: This is the first study to compare overall and progression-free survivals between CCMs and other WHO grade II meningiomas. Clear cell histology predicts a higher risk of tumor recurrence and mortality than other grade II histologies. Future studies may help to understand the impact of these findings and the treatment implications.

Extent of resection and survival outcomes in World Health Organization grade II meningiomas.

PURPOSE: WHO grade II meningiomas behave aggressively, with recurrence rates as high as 60%. Although complete resection in low-grade meningiomas is associated with a relatively low recurrence rate, the impact of complete resection for WHO grade II meningiomas is less clear. We studied the association of extent of resection with overall and progression-free survivals in patients with WHO grade II meningiomas. METHODS: A retrospective database review was performed to identify all patients who underwent surgical resection for intracranial WHO grade II meningiomas at our institution between 1995 and 2019. Kaplan-Meier analysis was used to compare overall and progression-free survivals between patients who underwent gross total resection (GTR) and those who underwent subtotal resection (STR). Multivariable Cox proportional-hazards analysis was used to identify independent predictors of tumor recurrence and mortality. RESULTS: Of 214 patients who underwent surgical resection for WHO grade II meningiomas (median follow-up 53.4 months), 158 had GTR and 56 had STR. In Kaplan-Meier analysis, patients who underwent GTR had significantly longer progression-free (p = 0.002) and overall (p = 0.006) survivals than those who underwent STR. In multivariable Cox proportional-hazards analysis, GTR independently predicted prolonged progression-free (HR 0.57, p = 0.038) and overall (HR 0.44, p = 0.017) survivals when controlling for age, tumor location, and adjuvant radiation. CONCLUSIONS: Extent of resection independently predicts progression-free and overall survivals in patients with WHO grade II meningiomas. In an era of increasing support for adjuvant treatment modalities in the management of meningiomas, our data support maximal safe resection as the primary goal in treatment of these patients.

Outcomes of salvage radiation for recurrent world health organization grade II meningiomas: a retrospective cohort study.

PURPOSE: The optimal modality of radiation-intensity-modulated radiation therapy (IMRT) or stereotactic radiosurgery (SRS)-in patients with recurrent WHO grade II meningiomas is not well-established. The purpose of this study was to compare progression-free survival (PFS) in patients undergoing salvage IMRT vs SRS. We compared PFS in those with and without history of prior radiation. METHODS: Forty-two patients with 71 tumor recurrences treated with IMRT or SRS were retrospectively reviewed. Thirty-two salvage treatments were performed on recurrent tumors never treated with prior radiation ('radiation-naïve' cohort), whereas 39 salvage treatments were performed on recurrent tumors previously treated with radiation ('re-treatment cohort'). RESULTS: In the 'radiation-naïve' cohort, 3-year PFS for IMRT and SRS was 68.8% and 60.7%, respectively (p = 0.61). The median tumor volume for patients treated with IMRT was significantly larger than for patients treated with SRS (5.7 vs 2.2 cm3; p = 0.04). The 3-year PFS for salvage IMRT or SRS in the 're-treatment' cohort was 45.4% vs 65.8% in the 'radiation-naïve' cohort (p = 0.008). When analyzing the outcome of multiple re-treatments, median PFS was 47 months for 1st or 2nd salvage radiation (IMRT or SRS) compared to 16 months for the 3rd or greater salvage radiation treatment (p = 0.003). CONCLUSION: For salvage radiation of recurrent grade II tumors that are 'radiation-naïve', comparable 3-year PFS rates were found between IMRT and SRS, despite the IMRT group having significantly larger tumors. Salvage radiation overall was less successful in the 're-treatment' cohort compared with the 'radiation-naïve' cohort. Additionally, the effectiveness of radiation significantly declines with successive salvage radiation treatments.

Endogenous insulin signaling in the RPE contributes to the maintenance of rod photoreceptor function in diabetes.

In diabetes, there are two major physiological aberrations: (i) Loss of insulin signaling due to absence of insulin (type 1 diabetes) or insulin resistance (type 2 diabetes) and (ii) increased blood glucose levels. The retina has a high proclivity to damage following diabetes, and much of the pathology seen in diabetic retinopathy has been ascribed to hyperglycemia and downstream cascades activated by increased blood glucose. However, less attention has been focused on the direct role of insulin on retinal physiology, likely due to the fact that uptake of glucose in retinal cells is not insulin-dependent. The retinal pigment epithelium (RPE) is instrumental in maintaining the structural and functional integrity of the retina. Recent studies have suggested that RPE dysfunction is a precursor of, and contributes to, the development of diabetic retinopathy. To evaluate the role of insulin on RPE cell function directly, we generated a RPE specific insulin receptor (IR) knockout (RPEIRKO) mouse using the Cre-loxP system. Using this mouse, we sought to determine the impact of insulin-mediated signaling in the RPE on retinal function under physiological control conditions as well as in streptozotocin (STZ)-induced diabetes. We demonstrate that loss of RPE-specific IR expression resulted in lower a- and b-wave electroretinogram amplitudes in diabetic mice as compared to diabetic mice that expressed IR on the RPE. Interestingly, RPEIRKO mice did not exhibit significant differences in the amplitude of the RPE-dependent electroretinogram c-wave as compared to diabetic controls. However, loss of IR-mediated signaling in the RPE reduced levels of reactive oxygen species and the expression of pro-inflammatory cytokines in the retina of diabetic mice. These results imply that IR-mediated signaling in the RPE regulates photoreceptor function and may play a role in the generation of oxidative stress and inflammation in the retina in diabetes.

Removal of Intrathecal Catheters Used in Drug Delivery Systems.

INTRODUCTION: Implanted intrathecal drug delivery systems (IDDS) are increasingly used in the treatment of spasticity and in patients with refractory pain. Literature discussing complications associated with intrathecal pump placement is widely available. However, reports of complications following the removal of chronically placed catheters are scarce. We reviewed our series of patients who had surgery to remove the intrathecal catheter. METHODS: Retrospective review was performed for all patients who underwent surgery to remove a catheter linked to an IDDS between 2010 and 2016. Patients older than 18 years were included in final analysis. Demographic (including age at removal, sex, BMI, and comorbidities) and etiologic characteristics (indications of IDDS implant and explant, interval between implant and explant, and concomitant surgery) were analyzed. Simple logistic regression was performed to seek any potential predictor of complications. RESULTS: Fifty-nine patients underwent removal of their intrathecal catheter after variable periods (mean interval of 189 months). On eight occasions, patients developed complications after catheter removal (mean interval between implant and explant was 76 months for these cases). Retained catheter was the cause of complications in half of these occasions. Persistent cerebrospinal fluid leak was the next most common complication, with requirement of an external ventricular drain and lumbar drain to facilitate wound healing on two separate occasions. CONCLUSION: Removal of an intrathecal catheter from IDDS systems may cause complications that in some cases require additional surgery.

The Safety and Efficacy of Using the O-Arm Intraoperative Imaging System for Deep Brain Stimulation Lead Implantation.

INTRODUCTION: Accurate electrode implantation is a major goal of deep brain stimulation (DBS) surgery. Intraoperative physiology with microelectrode recording (MER) is routinely used to refine stereotactic accuracy during awake electrode implantation. Recently, portable imaging systems such as the O-arm have become widely available and can be used in isolation or in association with MER to guide DBS lead placement. The aim of this study was to evaluate how the routine use of the O-arm affected DBS surgery safety, efficiency, and outcomes. METHODS: Two cohorts of patients with Parkinson's disease who underwent MER-guided awake subthalamic DBS lead implantation with and without O-arm were compared. We examined the total number of microelectrode and macroeletrode passes during each surgery, procedure duration, surgical complications, lead revisions, and motor outcomes. RESULTS: A total of 50 procedures in 41 unique patients were analyzed, of which 26 were performed without O-arm and 24 performed without the O-arm. The mean number of microelectrode passes was 2.46 (SD = 0.99) in the group without O-arm utilization, compared to 1.29 (SD = 0.75) in the group with O-arm usage (p < 0.001). A significant reduction was also found in procedure duration (p = 0.016). No differences were found in motor outcomes between groups. CONCLUSION: The use of the O-arm during DBS lead implantation was associated with significantly fewer brain cannulations for microelectrode recording as well as reduced surgical time.

C1-C2 Arthrodesis With C1 Lateral Mass and C2 Parsicle Screws Combined With Interlaminar Arthrodesis and Wiring.

C1-C2 arthrodesis is a common procedure performed for the correction of atlantoaxial instability due to a host of pathologies, including degenerative, neoplastic, congenital, and trauma. While there is clinical equipoise, C1-C2 fusion is associated with a lower morbidity than occipital-cervical fusion. However, due to the unique morphometric characteristics of the C1 lateral mass, and the challenges that its fixation presents, some surgeons may elect to extend the construct to the occiput rather than attempt a C1-C2 fusion. Here, we describe our freehand technique of safely and expeditiously performing a C1-C2 fusion with C1 lateral mass and C2 "parsicle" screws. In patients with high preprocedural probability to develop pseudarthrosis, we combine our instrumented fusion with interlaminar bone graft wiring, as similarly described by Gallie. We believe the C2 "parsicle" screw avoids the technical challenges of placing a traditional C2 pedicle screw and accommodates a much larger screw length than those placed in the C2 pars. Practical surgical tips, pearls, and potential complications are discussed in detail.

Radiographic Differentiation of Secretory Meningiomas and WHO Grade 2 Meningiomas: When Atypical Features Are Not Always Predictive of Atypical Tumors.

OBJECTIVE: Secretory meningioma (SM) is a rare subtype of World Health Organization (WHO) grade 1 meningioma, associated with significant peritumoral brain edema (PTBE). Because of this, SM may be mistaken preoperatively to be a WHO grade 2 meningioma (G2M). In this study, we identified radiographic features to differentiate these 2 tumor types preoperatively to help inform surgical decision-making. METHODS: We performed a retrospective review of all patients with histologically confirmed intracranial SM and G2M at a single institution from 2000 to 2019. Relevant clinic, demographic and radiographic data were collected. We performed a stepwise multivariable logistic regression to identify independent predictors of SM. RESULTS: A total of 43 SM and 140 G2M patients were included in this study. In multivariable analysis, severe PTBE, meaning edema size greater than tumor size (odds ratio [OR] 4.44, P = 0.01), tumor hyperintensity on fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging sequences (OR 7.80, P = 0.002), and higher normalized apparent diffusion coefficient (nADC) values (OR 1.54, P < 0.001) were strong predictors of SM. Conversely, larger tumor volume (OR 1.79 per 10 mL volume increase, P < 0.001) and cystic component (OR 12.50, P = 0.007) correlated with G2M. CONCLUSIONS: In this study, we found that preoperative FLAIR hyperintensity, severe PTBE, and higher nADC values correlated with SM pathology, and larger size and cystic component were associated with G2M. Accurate identification of SM on preoperative imaging may provide surgeons useful information in decision-making.

Adjuvant radiation versus observation with salvage radiation after gross-total resection of WHO grade II meningiomas: a propensity score-adjusted analysis.

OBJECTIVE: After gross-total resection (GTR) of a newly diagnosed WHO grade II meningioma, the decision to treat with radiation upfront or at initial recurrence remains controversial. A comparison of progression-free survival (PFS) between observation and adjuvant radiation fails to account for the potential success of salvage radiation, and a direct comparison of PFS between adjuvant and salvage radiation is hampered by strong selection bias against salvage radiation cohorts in which only more aggressive, recurrent tumors are included. To account for the limitations of traditional PFS measures, the authors evaluated radiation failure-free survival (RFFS) between two treatment strategies after GTR: adjuvant radiation versus observation with salvage radiation, if necessary. METHODS: The authors performed a retrospective review of patients who underwent GTR of newly diagnosed WHO grade II meningiomas at their institution between 1996 and 2019. They assessed traditional PFS in patients who underwent adjuvant radiation, postoperative observation, and salvage radiation. For RFFS, treatment failure was defined as time from initial surgery to failure of first radiation. To assess the association between treatment strategy and RFFS while accounting for potential confounders, a multivariable Cox regression analysis adjusted for the propensity score (PS) and inverse probability of treatment weighted (IPTW) Cox regression analysis were performed. RESULTS: A total of 160 patients underwent GTR and were included in this study. Of the 121 patients who underwent observation, 32 (26.4%) developed recurrence and required salvage radiation. PFS at 3, 5, and 10 years after observation was 75.1%, 65.6%, and 45.5%, respectively. PFS at 3 and 5 years after salvage radiation was 81.7% and 61.3%, respectively. Of 160 patients, 39 received adjuvant radiation, and 3- and 5-year PFS/RFFS rates were 86.1% and 59.2%, respectively. In patients who underwent observation with salvage radiation, if necessary, the 3-, 5-, and 10-year RFFS rates were 97.7%, 90.3%, and 87.9%, respectively. Both PS and IPTW Cox regression models demonstrated that patients who underwent observation with salvage radiation treatment, if necessary, had significantly longer RFFS (PS model: hazard ratio [HR] 0.21, p < 0.01; IPTW model: HR 0.21, p < 0.01). CONCLUSIONS: In this retrospective, nonrandomized study, adjuvant radiation after GTR of a WHO II meningioma did not add significant benefit over a strategy of observation and salvage radiation at initial recurrence, if necessary, but results must be considered in the context of the limitations of the study design.

Artificial Intelligence and Robotics in Spine Surgery.

STUDY DESIGN: Narrative review. OBJECTIVES: Artificial intelligence (AI) and machine learning (ML) have emerged as disruptive technologies with the potential to drastically affect clinical decision making in spine surgery. AI can enhance the delivery of spine care in several arenas: (1) preoperative patient workup, patient selection, and outcome prediction; (2) quality and reproducibility of spine research; (3) perioperative surgical assistance and data tracking optimization; and (4) intraoperative surgical performance. The purpose of this narrative review is to concisely assemble, analyze, and discuss current trends and applications of AI and ML in conventional and robotic-assisted spine surgery. METHODS: We conducted a comprehensive PubMed search of peer-reviewed articles that were published between 2006 and 2019 examining AI, ML, and robotics in spine surgery. Key findings were then compiled and summarized in this review. RESULTS: The majority of the published AI literature in spine surgery has focused on predictive analytics and supervised image recognition for radiographic diagnosis. Several investigators have studied the use of AI/ML in the perioperative setting in small patient cohorts; pivotal trials are still pending. CONCLUSIONS: Artificial intelligence has tremendous potential in revolutionizing comprehensive spine care. Evidence-based, predictive analytics can help surgeons improve preoperative patient selection, surgical indications, and individualized postoperative care. Robotic-assisted surgery, while still in early stages of development, has the potential to reduce surgeon fatigue and improve technical precision.

Cottonoid Sliders: A Simple and Cost-Effective Tool for Retractorless Intracranial Surgery.

BACKGROUND AND IMPORTANCE: Retraction injury can result in significant complications during intracranial operations. Alternative surgical techniques to minimize retraction pressure and duration of retraction can minimize the risk of retraction injury. We describe the use of a cottonoid "slider," which is a simple, cost-effective modification of a commonly used cottonoid, in multiple applications. CLINICAL PRESENTATION: The cottonoid sliders are constructed preoperatively by overlaying an adhesive plastic incision drape on one side of a dry cottonoid patty and trimming the edges to fit the form of the cottonoid. Intraoperatively, the sliders can slide across the parenchymal surface atraumatically and are used for gentle retraction to expose desired areas. In addition, suction may be placed on the slider to clear fluid from the operative view. The plastic side of the slider prevents adherence to the parenchymal surface. Retractorless surgical techniques have been developed to minimize risk of retractor associated injury in intracranial surgery by reducing retraction pressure and duration. Given that the cottonoid sliders glide along the parenchyma, do not stick, and are used for dynamic retraction, the main objectives to minimize retraction injury can be met while not compromising operative efficiency. CONCLUSION: Cottonoid sliders are a simple and cost-effective method of providing gentle exposure during intracranial surgery. This technique represents a valuable and cost-effective addition to the neurosurgical armamentarium.

Endoscopic Evacuation of Intracerebral Hematoma Utilizing a Side-Cutting Aspiration Device.

BACKGROUND: Intracerebral hemorrhage (ICH) is associated with a significant mortality of up to 50%, with almost all survivors suffering from debilitating functional compromise. In most cases, open craniotomy has failed to yield significant survival benefit. However, emerging evidence suggests that minimally invasive surgery (MIS) may yield clinically significant improvements in patient survival and quality of life in cases where open craniotomy has not shown benefit. CASE PRESENTATION: We report the first documented usage of a side-cutting-aspiration device via an endoscopic approach for the evacuation of a 56cc hematoma, which was a technical modification on previous MIS techniques. The patient is a 50-yr-old female who was transferred emergently to our center with a National Institutes of Health Stroke Scale score of 27 and found to have a large hematoma involving her left basal ganglia. A minimally-invasive approach was elected due to evidence on the risks and suboptimal outcomes of open craniotomy in ICH evacuation. Neuronavigation was used to plan the surgical trajectory for ICH access. Evacuation took place in three main steps: 1) beginning at the center of the clot to remove bulk; 2) mobilizing clots from parenchymal walls to a safe zone via aspiration, followed by clot homogenization; and 3) re-expansion of the cavity via continuous irrigation to allow visualization of further clots. A final inspection was performed to ensure removal of all clots that could be safely removed. The dual functionalities of the device, namely, suction only and suction plus side-cutting functions, enabled key maneuvers, such as clot homogenization and controlled aspiration strength, to be safely performed. A near-total evacuation of the hematoma was achieved without damage to surrounding parenchyma. The patient experienced a rapid clinical course from comatose to discharge-ready in 5 d. At 30-d follow-up, the patient had residual expressive aphasia and was able to ambulate with the assistance of a quad cane. There are no radiographical signs of recurrent hemorrhage or parenchymal injury. Clinical follow-up with this patient is ongoing. CONCLUSION: This is the first ICH evacuation with a side-cutting-aspiration device via an endoscopic approach. In our patient, this technique proved to be safe and efficacious, suggesting that this technique may be a promising addition to the armamentarium of MIS for ICH evacuation.

Comparative Effectiveness Between Primary and Revision Foraminotomy for the Treatment of Lumbar Foraminal Stenosis.

BACKGROUND: Foraminotomy has demonstrated clinical benefit in patients with lumbar foraminal stenosis (LFS), as evidenced by several small retrospective investigations. However, there is a subset of patients who have recurrent symptoms following the operation and therefore require revision surgery. Yet, despite this phenomenon, the relative efficacy of revision foraminotomy (RF) is not well elucidated due to limited literature on the quality of life (QOL) outcomes and cost associated with primary foraminotomy (PF) and RF. PURPOSE: To compare the effectiveness of PF and RF in terms of QOL outcomes and relative costs. STUDY DESIGN/SETTING: This is a retrospective cohort study conducted at a single tertiary-care institution. The patient sample consisted of patients undergoing foraminotomy for the treatment of LFS between 2008 and 2016. The primary outcome measure was improvement in postoperative QOL, as measured by EuroQol 5-Dimensions (EQ-5D), and secondary outcome measures included Pain Disability Questionnaire (PDQ) and Patient Health Questionnaire-9 (PHQ-9) perioperative cost as well as minimum clinically important difference (MCID). METHODS: A retrospective chart review was conducted to identify individuals who underwent PF or RF for LFS and to collect clinical, operative, and demographic data. QOL scores (EQ-5D, PDQ, and PHQ-9) were collected between 2008 and 2016, and perioperative financial data were extracted via the institution's cost utilization engine. Paired t tests were used to assess changes within treatment groups, and Fisher exact tests were used for intercohort comparisons. RESULTS: Five hundred seventy-nine procedures were eligible: 476 (82%) PF and 103 (18%) RF. A significantly higher proportion of males underwent RF than PF (71% versus 59%, P = .03), and PF was done on a significantly higher number of vertebral levels (2.2 versus 2.0, P = .04). There were no other significant differences in demographics. Preoperatively, mean PDQ-Functional scores (50 versus 54, P = .04) demonstrated significantly poorer QOL in the RF cohort. Postoperatively, EQ-5D index showed significant improvement in both the PF (0.547→0.648, P < .0001) and the RF (0.507→0.648, P < .0001) cohorts. Similarly, total PHQ-9 improved significantly in the PF cohort (7.84→5.91, P < .001) and in the RF cohort (8.55→5.53, P = .02), as did total PDQ (PF: 77→63, P < .0001; RF: 85→70, P = .04). QOL scores were also compared between groups preoperatively and postoperatively, and the only significant difference between PF and RF was observed in the preoperative PDQ-Functional score (49.7 versus 54.3, P = .04). The proportion of patients achieving MCID was not significantly associated with cohort. Finally, perioperative cost did not differ significantly between cohorts (PF: $13,383 versus RF: $13,595, P = .82). CONCLUSIONS: Both PF and RF produced significant improvement in nearly all measures in patients with LFS. There was no significant difference in cost between PF and RF, but both PF and RF showed postoperative QOL improvements as compared with preoperative scores, indicating that RF remains a reasonable treatment option for patients with recurrent symptoms of LFS.

A comprehensive epidemiological review of spinal astrocytomas in the United States.

OBJECTIVE: Spinal cord astrocytoma (SCA) is a rare tumor whose epidemiology has not been well defined. The authors utilized the Central Brain Tumor Registry of the United States (CBTRUS) to provide comprehensive up-to-date epidemiological data for this disease. METHODS: The CBTRUS was queried for SCAs on ICD-O-3 (International Classification of Diseases for Oncology, 3rd edition) histological and topographical codes. The age-adjusted incidence (AAI) per 100,000 persons was calculated and stratified by race, sex, age, and ethnicity. Joinpoint was used to calculate the annual percentage change (APC) in incidence. RESULTS: Two thousand nine hundred sixty-nine SCAs were diagnosed in the US between 1995 and 2016, resulting in an average of approximately 136 SCAs annually. The overall AAI was 0.047 (95% CI 0.045-0.049), and there was a statistically significant increase from 0.051 in 1995 to 0.043 in 2016. The peak incidence of 0.064 (95% CI 0.060-0.067) was found in the 0- to 19-year age group. The incidence in males was 0.053 (95% CI 0.050-0.055), which was significantly greater than the incidence in females (0.041, 95% CI 0.039-0.044). SCA incidence was significantly lower both in patients of Asian/Pacific Islander race (AAI = 0.034, 95% CI 0.028-0.042, p = 0.00015) and in patients of Hispanic ethnicity (AAI = 0.035, 95% CI 0.031-0.039, p < 0.001). The incidence of WHO grade I SCAs was significantly higher than those of WHO grade II, III, or IV SCAs (p < 0.001). CONCLUSIONS: The overall AAI of SCA from 1995 to 2016 was 0.047 per 100,000. The incidence peaked early in life for both sexes, reached a nadir between 20 and 34 years of age for males and between 35 and 44 years of age for females, and then slowly increased throughout adulthood, with a greater incidence in males. Pilocytic astrocytomas were the most common SCA in the study cohort. This study presents the most comprehensive epidemiological study of SCA incidence in the US to date.

Lessons Learned in Using Laser Interstitial Thermal Therapy for Treatment of Brain Tumors: A Case Series of 238 Patients from a Single Institution.

BACKGROUND: Laser interstitial thermal therapy (LITT) is a novel, minimally invasive alternative to craniotomy, and as with any new technology, comes with a learning curve. OBJECTIVE: We present our experience detailing the evolution of this technology in our practice in one of the largest patient cohorts to date regarding LITT in neuro-oncology. METHODS: We reviewed 238 consecutive patients with brain tumor treated with LITT at our institution. Data on patient, surgery and tumor characteristics, and follow-up were collected. Patients were categorized into 2 cohorts: early (<2014, 100 patients) and recent (>2015, 138 patients). Median follow-up for the entire cohort was 8.4 months. RESULTS: The indications for LITT included gliomas (70.2%), radiation necrosis (21.0%), and metastasis (8.8%). Patient demographics stayed consistent between the 2 cohorts, with the exception of age (early, 54.3; recent, 58.4; P = 0.04). Operative time (6.6 vs. 3.5; P < 0.001) and number of trajectories (53.1% vs. 77.9% with 1 trajectory; P < 0.001) also decreased in the recent cohort. There was a significant decrease in permanent motor deficits over time (15.5 vs. 4.4%; P = 0.005) and 30-day mortality (4.1% vs. 1.5%) also decreased (not statistically significant) in the recent cohort. In terms of clinical outcomes, poor preoperative Karnofsky Performance Status (≤70) were significantly correlated with increased permanent deficits (P = 0.001) and decreased overall survival (P < 0.001 for all time points). CONCLUSIONS: We observed improvement in operative efficiency and permanent deficits over time and also patients with poor preoperative Karnofsky Performance Status achieved suboptimal outcomes with LITT. As many other treatment modalities, patient selection is important in this procedure.

Predictors of second-sided deep brain stimulation for Parkinson's disease.

OBJECTIVE: Parkinson's disease (PD) is a progressive neurological movement disorder that is commonly treated with deep brain stimulation (DBS) surgery in advanced stages. The purpose of this study was to investigate factors that affect time to placement of a second-sided DBS lead for PD when a unilateral lead is initially placed for asymmetrical presentation. The decision whether to initially perform unilateral or bilateral DBS is largely based on physician and/or patient preference. METHODS: This study was a retrospective cohort analysis of patients with PD undergoing initial unilateral DBS for asymmetrical disease between January 1999 and December 2017 at the authors' institution. Patients treated with DBS for essential tremor or other conditions were excluded. Variables collected included demographics at surgery, time since diagnosis, Unified Parkinson's Disease Rating Scale motor scores (UPDRS-III), patient-reported quality-of-life outcomes, side of operation, DBS target, intraoperative complications, and date of follow-up. Paired t-tests were used to assess mean changes in UPDRS-III. Cox proportional hazards analysis and the Kaplan-Meier method were used to determine factors associated with time to second lead insertion over 5 years. RESULTS: The final cohort included 105 patients who underwent initial unilateral DBS for asymmetrical PD; 59% of patients had a second-sided lead placed within 5 years with a median time of 34 months. Factors found to be significantly associated with early second-sided DBS included patient age 65 years or younger, globus pallidus internus (GPi) target, and greater off-medication reduction in UPDRS-III score following initial surgery. Older age was also found to be associated with a smaller preoperative UPDRS-III levodopa responsiveness score and with a smaller preoperative to postoperative medication-off UPDRS-III change. CONCLUSIONS: Younger patients, those undergoing GPi-targeted unilateral DBS, and patients who responded better to the initial DBS were more likely to undergo early second-sided lead placement. Therefore, these patients, and patients who are more responsive to medication preoperatively (as a proxy for DBS responsiveness), may benefit from consideration of initial bilateral DBS.

The efficacy of intraoperative multimodal monitoring in pedicle subtraction osteotomies of the lumbar spine.

OBJECTIVE: Iatrogenic spine injury remains one of the most dreaded complications of pedicle subtraction osteotomies (PSOs) and spine deformity surgeries. Thus, intraoperative multimodal monitoring (IOM), which has the potential to provide real-time feedback on spinal cord signal transmission, has become the gold standard in such operations. However, while the benefits of IOM are well established in PSOs of the thoracic spine and scoliosis surgery, its utility in PSOs of the lumbar spine has not been robustly documented. The authors' aim was to determine the impact of IOM on outcomes in patients undergoing PSO of the lumbar spine. METHODS: All patients older than 18 years who underwent lumbar PSOs at the authors' institution from 2007 to 2017 were analyzed via retrospective chart review and categorized into one of two groups: those who had IOM guidance and those who did not. Perioperative complications were designated as the primary outcome measure and postoperative quality of life (QOL) scores, specifically the Parkinson's Disease Questionnaire-39 (PDQ-39) and Patient Health Questionnaire-9 (PHQ-9), were designated as secondary outcome measures. Data on patient demographics, surgical and monitoring parameters, and outcomes were gathered, and statistical analysis was performed to compare the development of perioperative complications and QOL scores between the two cohorts. In addition, the proportion of patients who reached minimal clinically important difference (MCID), defined as an increase of 4.72 points in the PDQ-39 score or a decrease of 5 points in the PHQ-9 score, in the two cohorts was also determined. RESULTS: A total of 95 patients were included in the final analysis. IOM was not found to significantly impact the development of new postoperative deficits (p = 0.107). However, the presence of preoperative neurological comorbidities was found to significantly correlate with postoperative neurological complications (p = 0.009). Univariate analysis showed that age was positively correlated with MCID achievement 3 months after surgery (p = 0.018), but this significance disappeared at the 12-month postoperative time point (p = 0.858). IOM was not found to significantly impact MCID achievement at either the 3- or 12-month postoperative period as measured by PDQ-39 (p = 0.398 and p = 0.156, respectively). Similarly, IOM was not found to significantly impact MCID achievement at either the 3- or 12-month postoperative period, as measured by PHQ-9 (p = 0.230 and p = 0.542, respectively). Multivariate analysis showed that female sex was significantly correlated with MCID achievement (p = 0.024), but this significance disappeared at the 12-month postoperative time point (p = 0.064). IOM was not found to independently correlate with MCID achievement in PDQ-39 scores at either the 3- or 12-month postoperative time points (p = 0.220 and p = 0.097, respectively). CONCLUSIONS: In this particular cohort, IOM did not lead to statistically significant improvement in outcomes in patients undergoing PSOs of the lumbar spine (p = 0.220). The existing clinical equipoise, however, indicates that future studies in this arena are necessary to achieve systematic guidelines on IOM usage in PSOs of the lumbar spine.

Intraoperative Multimodal Monitoring in Pedicle Subtraction Osteotomies of the Lumbar Spine: A Narrative Literature Review.

The use of intraoperative multimodal monitoring (IOM) in spinal deformity surgeries is well documented. In particular, pedicle subtraction osteotomy (PSO), a corrective procedure for sagittal deformity of the spine, often involves IOM usage. By providing immediate feedback to the operating surgeon, IOM has the potential to eliminate or at least minimize the risk of iatrogenic neurological injury. However, despite the widespread usage of IOM, there is currently no standardization of IOM usage in complex spine surgeries, including lumbar PSOs, and decisions concerning IOM utilization are often driven by surgeon experience and preference. This creates a state of clinical equipoise, which is further complicated by the varying degrees of benefit that IOM has on patient outcomes depending on the operation and spinal levels involved. For instance, while IOM use in thoracic PSOs has been shown to be effective, there is no established consensus on the net impact of IOM use in PSOs of the lumbar spine. Although IOM has the potential to mitigate neurological damage, it also increases operation time and cost; thus, it should only be used in operations where it will have a net positive impact on patient outcomes. The question thus becomes whether PSO of the lumbar spine is one such operation. To address this, we examine the most frequently used IOM modalities and evaluate their current usage and efficacy in lumbar PSOs. Furthermore, we will also examine the utility of IOM for other surgeries of the lumbar spine, including corrective procedures for idiopathic scoliosis and degenerative scoliosis, and routine lumbar procedures, such as discectomies and decompression surgeries for foraminal and canal stenosis.

Occlusion of the Ascenda Catheter in a Patient with Pump Twiddler's Sydrome: A Case Report.

INTRODUCTION: Intrathecal baclofen (ITB) therapy is an effective way to manage spasticity in numerous conditions, including multiple sclerosis, stroke, and cerebral palsy. While pump failure is a common complication of ITB, improvements in device design have led to reduction of complications. In particular, the Ascenda catheter from Medtronic, Inc. was designed to resist kinking and associated complications; indeed, no incidences of catheter twisting or occlusion have been reported in literature prior to this case. CASE REPORT: We report a case of a 32-year old gentleman who presented to the clinic with symptoms of baclofen withdrawal 19 months after he had a programmable pump implanted for spasticity. During the diagnostic evaluation it was discovered that the patients pump had flipped in his abdominal pocket. He was taken to surgery to reorient the pump, during which time it was noted the catheter was tightly coiled on itself occluding flow. The twisted catheter was excised and replaced with a new segment.His symptoms subsequently resolved. CONCLUSIONS: Although catheter occlusions have subsided since the approval of the Ascenda catheter, pump twiddler's syndrome remains a risk factor for this complication. This is the first report describing this syndrome in a patient with the Ascenda catheter.

Outcomes following deep brain stimulation lead revision or reimplantation for Parkinson's disease.

OBJECTIVEThe number of patients who benefit from deep brain stimulation (DBS) for Parkinson's disease (PD) has increased significantly since the therapy was first approved by the FDA. Suboptimal outcomes, infection, or device failure are risks of the procedure and may require lead removal or repositioning. The authors present here the results of their series of revision and reimplantation surgeries.METHODSThe data were reviewed from all DBS intracranial lead removals, revisions, or reimplantations among patients with PD over a 6-year period at the authors' institution. The indications for these procedures were categorized as infection, suboptimal outcome, and device failure. Motor outcomes as well as lead location were analyzed before removal and after reimplant or revision.RESULTSThe final sample included 25 patients who underwent 34 lead removals. Thirteen patients had 18 leads reimplanted after removal. There was significant improvement in the motor scores after revision surgery among the patients who had the lead revised for a suboptimal outcome (p = 0.025). The mean vector distance of the new lead location compared to the previous location was 2.16 mm (SD 1.17), measured on an axial plane 3.5 mm below the anterior commissure-posterior commissure line. When these leads were analyzed by subgroup, the mean distance was 1.67 mm (SD 0.83 mm) among patients treated for infection and 2.73 mm (SD 1.31 mm) for those with suboptimal outcomes.CONCLUSIONSPatients with PD who undergo reimplantation surgery due to suboptimal outcome may experience significant benefits. Reimplantation after surgical infection seems feasible and overall safe.