Beth Parente

Effect of Advancing Age on Outcomes of Deep Brain Stimulation for Parkinson Disease

IMPORTANCE Deep brain stimulation (DBS) is a well-established modality for the treatment of advanced Parkinson disease (PD). Recent studies have found DBS plus best medical therapy to be superior to best medical therapy alone for patients with PD and early motor complications. Although no specific age cutoff has been defined, most clinical studies have excluded patients older than 75 years of age. We hypothesize that increasing age would be associated with an increased number of postoperative complications. OBJECTIVE To evaluate the stepwise effect of increasing age (in 5-year epochs) on short-term complications following DBS surgery. DESIGN, SETTING, AND PARTICIPANTS A large, retrospective cohort study was performed using the Thomson Reuters MarketScan national database that examined 1757 patients who underwent DBS for PD during the period from 2000 to 2009. MAIN OUTCOMES AND MEASURES Primary measures examined included hospital length of stay and aggregate and individual complications within 90 days following surgery. Multivariate logistic regression analysis was used to calculate complication-related odds ratios (ORs) for each 5-year age epoch after controlling for covariates. RESULTS Overall, 132 of 1757 patients (7.5%) experienced at least 1 complication within 90 days, including wound infections (3.6%), pneumonia (2.3%), hemorrhage or hematoma (1.4%), or pulmonary embolism (0.6%). After adjusting for covariates, we found that increasing age (ranging from <50 to 90 years of age) did not significantly affect overall 90-day complication rates (OR, 1.10 per 5-year increase [95% CI, 0.96-1.25]; P = .17). The 2 most common procedure-related complications, hemorrhage (OR, 0.82 [95% CI, 0.63-1.07]; P = .14) and infection (OR, 1.04 [95% CI, 0.87-1.24]; P = .69), did not significantly increase with age. CONCLUSIONS AND RELEVANCE Older patients with PD (>75 years) who were selected to undergo DBS surgery showed a similar 90-day complication risk (including postoperative hemorrhage or infection) compared with younger counterparts. Our findings suggest that age alone should not be a primary exclusion factor for determining candidacy for DBS. Instead, a clear focus on patients with medication-refractory and difficult to control on-off fluctuations with preserved cognition, regardless of age, may allow for an expansion of the traditional therapeutic window.

Postmortem diffusion MRI of the human brainstem and thalamus for deep brain stimulator electrode localization

Deep brain stimulation (DBS) is an established surgical therapy for medically refractory tremor disorders including essential tremor (ET) and is currently under investigation for use in a variety of other neurologic and psychiatric disorders. There is growing evidence that the anti‐tremor effects of DBS for ET are directly related to modulation of the dentatorubrothalamic tract (DRT), a white matter pathway that connects the cerebellum, red nucleus, and ventral intermediate nucleus of the thalamus. Emerging white matter targets for DBS, like the DRT, will require improved three‐dimensional (3D) reference maps of deep brain anatomy and structural connectivity for accurate electrode targeting. High‐resolution diffusion MRI of postmortem brain specimens can provide detailed volumetric images of important deep brain nuclei and 3D reconstructions of white matter pathways with probabilistic tractography techniques. We present a high spatial and angular resolution diffusion MRI template of the postmortem human brainstem and thalamus with 3D reconstructions of the nuclei and white matter tracts involved in ET circuitry. We demonstrate registration of these data to in vivo, clinical images from patients receiving DBS therapy, and correlate electrode proximity to tractography of the DRT with improvement of ET symptoms. Hum Brain Mapp 36:3167–3178, 2015.

The Incidence of Spinal Cord Injury in Implantation of Percutaneous and Paddle Electrodes for Spinal Cord Stimulation

Spinal cord stimulation (SCS) has been proven effective for multiple chronic pain syndromes. Over the past 40 years of use, the complication rates of SCS have been well defined in the literature; however, the incidence of one of the most devastating complications, spinal cord injury (SCI), remains largely unknown. The goal of the study was to quantify the incidence of SCI in both percutaneous and paddle electrode implantation.

Impact of advancing age on post-operative complications of deep brain stimulation surgery for essential tremor

Essential tremor (ET) was the original indication for deep brain stimulation (DBS), with USA Food and Drug Administration approval since 1997. Despite the efficacy of DBS, it is associated with surgical complications that cause sub-optimal clinical outcomes. Given that ET is a progressive disease with increase in symptom severity with increasing age, this study evaluated the impact of increasing age on short-term complications following DBS surgery for ET. The Thomson-Reuters MarketScan database was utilized (New York, NY, USA). Patients selected were over age 18 and underwent DBS for ET between the years 2000 and 2009. Multivariable logistic regression analysis was used to calculate complication odds ratios (OR) for a 5 year increase in age, after controlling for other covariates. Six hundred sixty-one patients were included in the analysis. The mean (standard deviation) age was 61.9 (14.3) years, with 17% of individuals aged ⩾75 years. Overall 56.9% of patients were male, and 44.6% had a Charlson Comorbidity Score of ⩾1. Additionally, 7.1% of patients experienced at least one complication within 90 days, including wound infections (3.0%), pneumonia (2.4%), hemorrhage or hematoma (1.5%), or pulmonary embolism (0.6%). Increasing age was not significantly associated with the overall 90 day complication rates (OR 0.89; 95% confidence interval [CI] 0.77-1.02; p=0.102). The risk of the two most common procedure-related complications, hemorrhage and infection, did not significantly increase with age (hemorrhage: OR 1.02; 95%CI 0.77-1.37; p=0.873; and infection: OR 0.88; 95%CI 0.72-1.07; p=0.203). Our findings suggest that age should not be a primary exclusion factor for determining candidacy for DBS and also suggest a possible expansion of the traditional therapeutic window since post-operative complications remained relatively stable.

Comparison of Bilateral vs. Staged Unilateral Deep Brain Stimulation (DBS) in Parkinson's Disease in Patients Under 70 Years of Age

The most popular surgical method for deep brain stimulation (DBS) in Parkinsons disease (PD) is simultaneous bilateral DBS. However, some centers conduct a staged unilateral approach advocating that reduced continuous intraoperative time reduces postoperative complications, thus justifying the cost of a second operative session. To test these assumptions, we performed a retrospective analysis of the Truven Health MarketScan® Database.

The Volume-Outcome Effect: Impact on Trial-to-Permanent Conversion Rates in Spinal Cord Stimulation

Conversion rates from trial leads to permanent spinal cord stimulation (SCS) systems have important implications for healthcare resource utilization (HCRU) and pain management. We hypothesized that there is a volume‐outcome effect, with chronic pain patients who visit high volume SCS implanters will have higher trial‐to‐permanent conversion rates.

Drivers and Risk Factors of Unplanned 30-Day Readmission Following Spinal Cord Stimulator Implantation

Unplanned 30‐day readmission rates contribute significantly to growing national healthcare expenditures. Drivers of unplanned 30‐day readmission after spinal cord stimulator (SCS) implantation are relatively unknown. The aim of this study was to determine drivers of 30‐day unplanned readmission following SCS implantation.

Specialty-Based Variations in Spinal Cord Stimulation Success Rates for Treatment of Chronic Pain

Spinal cord stimulation (SCS) has emerged as an appropriate modality of treatment for intractable chronic pain. The present study examines variations in SCS trial‐to‐permanent conversion rates based on provider types performing the procedure.

Explantation Rates and Healthcare Resource Utilization in Spinal Cord Stimulation

Certain patients ultimately undergo explantation of their spinal cord stimulation (SCS) devices. Understanding the predictors and rates of SCS explantation has important implications for healthcare resource utilization (HCRU) and pain management. The present study identifies explant predictors and discerns differences in HCRU for at‐risk populations.

Down the Rabbit Hole: Specialty Influence on SCS Outcomes: LETTER TO THE EDITOR

We were very interested to read the letter “Through the Looking Glass” by Boortz-Marx and colleagues in response to our original manuscript, “Specialty-Based Variations in Spinal Cord Stimulation Success Rates for Treatment of Chronic Pain” (1). We are pleased that our work has generated interest by expert investigators in the neuromodulation community. Our intent was not to step through Lewis Carroll’s mirror into Alice in Wonderland’s strange and mysterious world. We are not going down the rabbit hole of pitting one or more specialties that offer neuromodulation approaches against one another. We also care deeply about the field of neuromodulation and want to ensure that we are not simply going “Somewhere,” but in a direction that allows sustainability and expansion of the field for the benefit of patients everywhere. Neuromodulation is a growing field, with an increasing number of specialties participating, offering novel approaches for previously untreatable and medically refractory conditions. The goal of our manuscript was to shed light on the need to better standardize education and training across multiple specialties that choose to incorporate neuromodulation approaches into their practices.