Faculty Bibliography

The emergence of liquid biopsy technologies holds great promise in the cancer setting, including in pediatric central nervous system (CNS) tumors. In contrast to broad lower-depth sequencing, commonly referred to as low pass whole genome sequencing (WGS), targeted platforms with a higher depth of coverage have also been established. Here, we review targeted liquid biopsy techniques with applicability to pediatric CNS tumors. These include polymerase chain reaction (PCR), both droplet digital PCR and reverse transcription-based PCR, Sanger sequencing, and next-generation sequencing approaches that incorporate amplicon- and hybrid capture-based methods. The goal of this paper is to facilitate an understanding of these targeted techniques and provide a context for clinical relevance within disease categories, as well as a discussion on optimizing real-world implementation for pediatric CNS tumors.

BACKGROUND/UNASSIGNED:Despite the lack of FDA (Food and Drug Administration) approval, cervical and lumbar epidural spinal injections are frequently performed in the US to address back pain and/or painful radiculopathy. The three major types of injections include; interlaminar/translaminar (ESI), transforaminal (TFESI), or caudal injections. Notably, most studies document little to no clear short-term, and no long-term benefits/efficacy for these injections vs. various placebos. METHODS/UNASSIGNED:More adverse events (AE) occurred with cervical© rather than lumbar (L) injections, and more severe AE were attributed to C-TFESI vs. CESI injections. RESULTS/UNASSIGNED:nerve cranial palsies. AE for lumbar LESI/L-TFESI included; infections/abscess, epidural hematomas/subdural hematomas, intravascular injections, cerebrospinal fluid (CSF) leaks/dural tears (DT), and intracranial/postural hypotension. Notably, the vast majority of studies showed little to no short-term, and no long-term benefits for cervical or lumbar ESI/TFESI vs placebos (i.e. mostly consisting of normal saline alone, or saline plus local anesthesia). CONCLUSION/UNASSIGNED:Epidural cervical and lumbar ESI or TFESI spinal injections demonstrated minimal to no short-term, and no long-term benefits for the treatment of cervical and/or lumbar pain/radiculopathy vs. placebos. Further, more AE were observed for cervical vs. lumbar epidural injections overall, with more AE usually seen with TFESI vs. ESI procedures.

Cortical regions supporting speech production are commonly established using neuroimaging techniques in both research and clinical settings. However, for neurosurgical purposes, structural function is routinely mapped peri-operatively using direct electrocortical stimulation. While this method is the gold standard for identification of eloquent cortical regions to preserve in neurosurgical patients, there is lack of specificity of the actual underlying cognitive processes being interrupted. To address this, we propose mapping the temporal dynamics of speech arrest across peri-sylvian cortices by quantifying the latency between stimulation and speech deficits. In doing so, we are able to substantiate hypotheses about distinct region-specific functional roles (e.g. planning versus motor execution). In this retrospective observational study, we analysed 20 patients (12 female; age range 14-43) with refractory epilepsy who underwent continuous extra-operative intracranial EEG monitoring of an automatic speech task during clinical bedside language mapping. Latency to speech arrest was calculated as time from stimulation onset to speech arrest onset, controlling for individual speech rate. Most instances of motor-based arrest (87.5% of 96 instances) were in sensorimotor cortex with mid-range latencies to speech arrest with a distributional peak at 0.47 s. Speech arrest occurred in numerous regions, with relatively short latencies in supramarginal gyrus (0.46 s), superior temporal gyrus (0.51 s) and middle temporal gyrus (0.54 s), followed by relatively long latencies in sensorimotor cortex (0.72 s) and especially long latencies in inferior frontal gyrus (0.95 s). Non-parametric testing for speech arrest revealed that region predicted latency; latencies in supramarginal gyrus and in superior temporal gyrus were shorter than in sensorimotor cortex and in inferior frontal gyrus. Sensorimotor cortex is primarily responsible for motor-based arrest. Latencies to speech arrest in supramarginal gyrus and superior temporal gyrus (and to a lesser extent middle temporal gyrus) align with latencies to motor-based arrest in sensorimotor cortex. This pattern of relatively quick cessation of speech suggests that stimulating these regions interferes with the outgoing motor execution. In contrast, the latencies to speech arrest in inferior frontal gyrus and in ventral regions of sensorimotor cortex were significantly longer than those in temporoparietal regions. Longer latencies in the more frontal areas (including inferior frontal gyrus and ventral areas of precentral gyrus and postcentral gyrus) suggest that stimulating these areas interrupts a higher-level speech production process involved in planning. These results implicate the ventral specialization of sensorimotor cortex (including both precentral and postcentral gyri) for speech planning above and beyond motor execution.

BACKGROUND/UNASSIGNED:Morbid obesity (MO) is defined by the World Health Organization (WHO) as Class II (i.e. Body Mass Index (BMI) >/= 35 kg/M2 + 2 comorbidities) or Class III (i.e. BMI >/= 40 kg/M2). Here, we reviewed the rates for adverse event/s (AE)/morbidity/mortality for MO patients undergoing anterior cervical surgery as inpatients/in-hospitals, and asked whether this should be considered the standard of care? METHODS/UNASSIGNED:We reviewed multiple studies to document the AE/morbidity/mortality rates for performing anterior cervical surgery (i.e., largely ACDF) for MO patients as inpatients/in-hospitals. RESULTS/UNASSIGNED:MO patients undergoing anterior cervical surgery may develop perioperative/postoperative AE, including postoperative epidural hematomas (PEH), that can lead to acute/delayed cardiorespiratory arrests. MO patients in-hospitals have 24/7 availability of anesthesiologists (i.e. to intubate/run codes) and surgeons (i.e. to evacuate anterior acute hematomas) who can best handle typically witnessed cardiorespiratory arrests. Alternatively, after average 4-7.5 hr. postoperative care unit (PACU) observation, Ambulatory Surgical Center (ASC) patients are sent to unmonitored floors for the remainder of their 23-hour stays, while those in Outpatient SurgiCenters (OSC) are discharged home. Either for ASC or OSC patients, cardiorespiratory arrests are usually unwitnessed, and, therefore, are more likely to lead to greater morbidity/mortality. CONCLUSION/UNASSIGNED:Anterior cervical surgery for MO patients is best/most safely performed as inpatients/in-hospitals where significant postoperative AE, including cardiorespiratory arrests, are most likely to be witnessed events, and appropriately emergently treated with better outcomes. Alternatively, MO patients undergoing anterior cervical procedures in ASC/OSC will more probably have unwitnessed AE/cardiorespiratory arrests, resulting in poorer outcomes with higher mortality rates. Given these findings, isn't it safest for MO patients to undergo anterior cervical surgery as inpatients/in-hospitals, and shouldn't this be considered the standard of care?

BACKGROUND/UNASSIGNED:The incidence of cerebrospinal fluid (CSF) leaks/dural tears (DT) occurring during anterior cervical diskectomy and fusion (ACDF) are typically relatively low. However, this frequency markedly increases when anterior corpectomy and fusion (ACF) are performed to address ossification of the posterior longitudinal ligament (OPLL). METHODS/UNASSIGNED:The reported frequencies of CSF leaks/DT occurring during elective ACDF (i.e. exclusive of trauma), ranges from 0.24% to 1.7%. Notably, this incidence substantially rises for multilevel ACF addressing anterior OPLL, markedly varying from 3.4 - 44.7%. RESULTS/UNASSIGNED:The classical risks of anterior cervical CSF leaks/DT with anterior cervical surgery may be minimized utilizing an operating microscope. For OPLL, careful evaluation of preoperative non-contrast CT studies is critical, especially to document whether any of the 3 signs of dural penetrance is present. Here, posterior operative choices should be strongly considered in the presence of sufficient lordosis and/or a Positive K Line (+ K Line) as this will avoid an anterior cervical CSF leak/dural fistula. Alternatively, for patients with kyphosis and a Negative K Line (- K Line), preoperative anticipation and planning to treat an intraoperative anterior CSF leak/DT (i.e. direct anterior primary dural graft repair with 7-0 Gore-Tex sutures, microdural staples, microfibrillar collagen, wound-peritoneal shunt, and lumbar drain or lumboperitneal shunt) are essential in the course of performing direct anterior OPLL resection. CONCLUSION/UNASSIGNED:The incidence of anterior cervical CSF leaks/DT is relatively low (i.e. range 0.24 - 1.7%) where ACDF is performed for disc disease/spur/spondylosis exclusive of OPLL. However, where ACF is performed for multilevel OPLL, the risk of CSF Leaks/DT is substantially higher (i.e. range 4.3-44.7%).

BACKGROUND/UNASSIGNED:Musician's focal task-specific dystonia is a complex disorder of fine motor control, with incomplete understanding of its etiology. There have been relatively few trials of botulinum toxin in upper limb task-specific dystonia, and prior studies have yielded variable results, leading to skepticism regarding the utility of this approach in elite performers. METHODS/UNASSIGNED:We conducted a double-blind, placebo-controlled, randomized, cross-over study of incobotulinum toxin-A in 21 professional musicians with focal upper extremity task-specific dystonia affecting performance on their instrument, using a novel paradigm of initial injections followed by booster injections at two- and four-week intervals. The primary outcome measure was the change in blinded dystonia rating of the active arm by two expert raters using a Clinical Global Impression numeric scale at week 8 compared to enrollment. FINDINGS/UNASSIGNED:19 men and 2 women with musicians' dystonia were enrolled over a six-year period. Nineteen patients completed the study. Analysis of the primary outcome measure in comparison to baseline revealed a change in dystonia severity of P = 0.04 and an improvement in overall musical performance of P = 0.027. No clinically significant weakness was observed, and neutralizing antibodies to toxin were not found. INTERPRETATION/UNASSIGNED:Despite its small sample size, our study demonstrated a statistically significant benefit of incobotulinum toxin-A injections as a treatment for musicians' task-specific dystonia. Tailoring the use of toxin with booster injections allowed refinement of dosing strategy and outcomes, with benefits that were meaningful to patients clearly visible on videotaped evaluations. In addition to its application to musicians' dystonia, this approach may have relevance to optimize application of botulinum toxin in other forms of focal dystonia such as blepharospasm, cervical dystonia, writer's cramp, and spasmodic dysphonia.

BACKGROUND:Parkinson's disease (PD) is a complex neurodegenerative disorder impacting everyday function and quality of life. Rehabilitation plays a crucial role in improving symptoms, function, and quality of life and reducing disability, particularly given the lack of disease-modifying agents and limitations of medications and surgical therapies. However, rehabilitative care is under-recognized and under-utilized in PD and often only utilized in later disease stages, despite research and guidelines demonstrating its positive effects. Currently, there is a lack of consensus regarding fundamental topics related to rehabilitative services in PD. OBJECTIVE:The goal of the international Parkinson's Foundation Rehabilitation Medicine Task Force was to develop a consensus statement regarding the incorporation of rehabilitation in PD care. METHODS:The Task Force, comprised of international multidisciplinary experts in PD and rehabilitation and people directly affected by PD, met virtually to discuss topics such as rehabilitative services, existing therapy guidelines and rehabilitation literature in PD, and gaps and needs. A systematic, interactive, and iterative process was used to develop consensus-based statements on core components of PD rehabilitation and discipline-specific interventions. RESULTS:The expert-based consensus statement outlines key tenets of rehabilitative care including its multidisciplinary approach and discipline-specific guidance for occupational therapy, physical therapy, speech language pathology/therapy, and psychology/neuropsychology across all PD stages. CONCLUSIONS:Rehabilitative interventions should be an essential component in the comprehensive treatment of PD, from diagnosis to advanced disease. Greater education and awareness of the benefits of rehabilitative services for people with PD and their care partners, and further evidence-based and scientific study are encouraged.

Symptoms of autonomic dysfunction are prevalent and can be very debilitating, reducing the quality of life in patients with Parkinson's disease (PD) and other synucleinopathies such as dementia with Lewy bodies and multiple system atrophy. Non-pharmacological therapies are key to effective management and are frequently used alone in patients with mild autonomic symptoms, or in combination with pharmacological therapies in patients with moderate and severe symptoms. This article focuses on non-pharmacological approaches. Our objective was to review the non-drug and non-surgical approaches to treating autonomic symptoms in patients with PD and other synucleinopathies, focusing on cardiovascular, gastrointestinal, and genitourinary autonomic dysfunction. Evidence supporting the effectiveness of non-pharmacological treatment for the management of neurogenic orthostatic hypotension, supine hypertension, constipation, and bladder and sexual dysfunction is available. High-quality prospective trials are scarce, yet some non-pharmacological interventions (e.g., physical counter maneuvers) can be evaluated relatively quickly on an individual basis and often seem effective. The emerging variety of clinical presentations advocates for a stepwise, individualized, and non-pharmacological approach for the management of autonomic symptoms. Often, the first step is to reduce or discontinue drugs that cause or aggravate autonomic symptoms followed by lifestyle measures. While non-pharmacological and non-surgical treatments are available and, in many cases, effective to improve symptoms of autonomic dysfunction in PD and other synucleinopathies, they are often overlooked. Large randomized trials testing and comparing non-pharmacological approaches are warranted.

In medication-resistant epilepsy, the goal of epilepsy surgery is to make a patient seizure free with a resection/ablation that is as small as possible to minimize morbidity. The standard of care in planning the margins of epilepsy surgery involves electroclinical delineation of the seizure-onset zone and incorporation of neuroimaging findings from MRI, PET, single-photon emission CT and magnetoencephalography modalities. Resecting cortical tissue generating high-frequency oscillations has been investigated as a more efficacious alternative to targeting the seizure-onset zone. In this study, we used a support vector machine (SVM), with four distinct fast ripple (FR: 350-600 Hz on oscillations, 200-600 Hz on spikes) metrics as factors. These metrics included the FR resection ratio, a spatial FR network measure and two temporal FR network measures. The SVM was trained by the value of these four factors with respect to the actual resection boundaries and actual seizure-free labels of 18 patients with medically refractory focal epilepsy. Leave-one-out cross-validation of the trained SVM in this training set had an accuracy of 0.78. We next used a simulated iterative virtual resection targeting the FR sites that were of highest rate and showed most temporal autonomy. The trained SVM utilized the four virtual FR metrics to predict virtual seizure freedom. In all but one of the nine patients who were seizure free after surgery, we found that the virtual resections sufficient for virtual seizure freedom were larger in volume (P < 0.05). In nine patients who were not seizure free, a larger virtual resection made five virtually seizure free. We also examined 10 medically refractory focal epilepsy patients implanted with the responsive neurostimulator system and virtually targeted the responsive neurostimulator system stimulation contacts proximal to sites generating FR at highest rates to determine if the simulated value of the stimulated seizure-onset zone and stimulated FR metrics would trend towards those patients with a better seizure outcome. Our results suggest the following: (i) FR measures can accurately predict whether a resection, defined by the standard of care, will result in seizure freedom; (ii) utilizing FR alone for planning an efficacious surgery can be associated with larger resections; (iii) when FR metrics predict the standard-of-care resection will fail, amending the boundaries of the planned resection with certain FR-generating sites may improve outcome and (iv) more work is required to determine whether targeting responsive neurostimulator system stimulation contact proximal to FR generating sites will improve seizure outcome.