Disease applications of spinal cord stimulation: Chronic nonmalignant pain

Neuropathic pain is a chronic condition representing a significant burden for society. It is estimated 1 out of 10 people over the age of 30 that in the US have been diagnosed with neuropathic pain. Most of the available treatments for neuropathic pain have moderate efficacy over time which limit their use; therefore, other therapeutic approaches are needed for patients. Spinal cord stimulation is an established and cost-effective modality for treating severe chronic pain. In this article we will review the current approved indications for the use of spinal cord stimulation in the US and the novel therapeutic options which are now available using this therapy.

Comparison of hydrogel coils versus bare platinum coils for the treatment of anterior communicating artery aneurysms

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Neuromodulation for Chronic Pelvic Pain: A Single-Institution Experience With a Collaborative Team

BACKGROUND

Secondary to the complex care, involved specialty providers, and various etiologies, chronic pelvic pain patients do not receive holistic care.

OBJECTIVE

To compare our general and neuromodulation cohorts based on referrals, diagnosis, and therapy and describe our neuromodulation patients.

METHODS

A multidisciplinary team was established at our center. The intake coordinator assessed demographics and facilitated care of enrolled patients. Outcomes were compared using minimal clinical important difference of current Numerical Rating Scale (NRS) between patients with neuropathic pain who received neuromodulation and those who did not. The neuromodulation cohort completed outcome metrics at baseline and recent follow-up, including NRS score (best, worst, and current), Oswestry Disability Index (ODI), Beck Depression Inventory, and Pain Catastrophizing Scale.

RESULTS

Over 7 yr, 233 patients were referred to our consortium and 153 were enrolled. A total of 55 patients had neuropathic pain and 44 of those were managed medically. Eleven underwent neuromodulation. A total of 45.5% patients of the neuromodulation cohort were classified as responders by minimal clinically important difference compared to 26.6% responders in the control cohort at most recent follow-up (median 25 and 33 mo, respectively). Outcome measures revealed improvement in NRS at worst (P = .007) and best (P = .025), ODI (P = .014), and Pain Catastrophizing Scale Rumination (P = .043).

CONCLUSION

Eleven percent of patients were offered neuromodulation. There were more responders in the neuromodulation cohort than the conservatively managed neuropathic pain cohort. Neuromodulation patients showed significant improvement at 29 mo in NRS best and worst pain, disability, and rumination. We share our algorithm for patient management.

A Systematic Review of Deep Brain Stimulation Targets for Obsessive Compulsive Disorder

BACKGROUND

Obsessive compulsive disorder (OCD) is a complex neuropsychiatric disease characterized by obsessions and compulsions. Deep brain stimulation (DBS) has demonstrated efficacy in improving symptoms in medically refractory patients. Multiple targets have been investigated.

OBJECTIVE

To systematically review the current level and quality of evidence supporting OCD-DBS by target region with the goal of establishing a common nomenclature.

METHODS

A systematic literature review was performed using the PubMed database and a patient/problem, intervention, comparison, outcome search with the terms "DBS" and "OCD." Of 86 eligible articles that underwent full-text review, 28 were included for review. Articles were excluded if the target was not specified, the focus on nonclinical outcomes, the follow-up period shorter than 3 mo, or the sample size smaller than 3 subjects. Level of evidence was assigned according to the American Association of Neurological Surgeons/Congress of Neurological Surgeons joint guideline committee recommendations. Quality of evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach.

RESULTS

Selected publications included 9 randomized controlled trials, 1 cohort study, 1 case-control study, 1 cross-sectional study, and 16 case series. Striatal region targets such as the anterior limb of the internal capsule, ventral capsule/ventral striatum, and nucleus accumbens were identified, but stereotactic coordinates were similar despite differing structural names. Only 15 of 28 articles included coordinates.

CONCLUSION

The striatal area is the most commonly targeted region for OCD-DBS. We recommend a common nomenclature based on this review. To move the field forward to individualized therapy, active contact location relative to stereotactic coordinates and patient specific anatomical and clinical variances need to be reported.

Use of Functional Magnetic Resonance Imaging to Assess How Motor Phenotypes of Parkinson's Disease Respond to Deep Brain Stimulation

BACKGROUND

Deep brain stimulation (DBS) is a well-accepted treatment of Parkinson's disease (PD). Motor phenotypes include tremor-dominant (TD), akinesia-rigidity (AR), and postural instability gait disorder (PIGD). The mechanism of action in how DBS modulates motor symptom relief remains unknown.

OBJECTIVE

Blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) was used to determine whether the functional activity varies in response to DBS depending on PD phenotypes.

MATERIALS AND METHODS

Subjects underwent an fMRI scan with DBS cycling ON and OFF. The effects of DBS cycling on BOLD activation in each phenotype were documented through voxel-wise analysis. For each region of interest, ANOVAs were performed using T-values and covariate analyses were conducted. Further, a correlation analysis was performed comparing stimulation settings to T-values. Lastly, T-values of subjects with motor improvement were compared to those who worsened.

RESULTS

As a group, BOLD activation with DBS-ON resulted in activation in the motor thalamus (p < 0.01) and globus pallidus externa (p < 0.01). AR patients had more activation in the supplementary motor area (SMA) compared to PIGD (p < 0.01) and TD cohorts (p < 0.01). Further, the AR cohort had more activation in primary motor cortex (MI) compared to the TD cohort (p = 0.02). Implanted nuclei (p = 0.01) and phenotype (p = <0.01) affected activity in MI and phenotype alone affected SMA activity (p = <0.01). A positive correlation was seen between thalamic activation and pulse-width (p = 0.03) and between caudate and total electrical energy delivered (p = 0.04).

CONCLUSIONS

These data suggest that DBS modulates network activity differently based on patient motor phenotype. Improved understanding of these differences may further our knowledge about the mechanisms of DBS action on PD motor symptoms and to optimize treatment.

Robotic Assisted MRI-Guided Interventional Interstitial MR-Guided Focused Ultrasound Ablation in a Swine Model

BACKGROUND

Ablative lesions are current treatments for epilepsy and brain tumors. Interstitial magnetic resonance (MR) guided focused ultrasound (iMRgFUS) may be an alternate ablation technique which limits thermal tissue charring as compared to laser therapy (LITT) and can produce larger ablation patterns nearer the surface than transcranial MR guided focused ultrasound (tcMRgFUS).

OBJECTIVE

To describe our experience with interstitial focused ultrasound (iFUS) ablations in swine, using MR-guided robotically assisted (MRgRA) delivery.

METHODS

In an initial 3 animals, we optimized the workflow of the robot in the MR suite and made modifications to the robotic arm to allow range of motion. Then, 6 farm pigs (4 acute, 2 survival) underwent 7 iMRgFUS ablations using MRgRA. We altered dosing to explore differences between thermal dosing in brain as compared to other tissues. Imaging was compared to gross examination.

RESULTS

Our work culminated in adjustments to the MRgRA, iMRgFUS probes, and dosing, culminating in 2 survival surgeries; swine had ablations with no neurological sequelae at 2 wk postprocedure. Immediately following iMRgFUS therapy, diffusion-weighted imaging, and T1 weighted MR were accurate reflections of the ablation volume. T2 and fluid-attenuated inversion-recovery (FLAIR) images were accurate reflections of ablation volume 1-wk postprocedure.

CONCLUSION

We successfully performed MRgRA iFUS ablation in swine and found intraoperative and postoperative imaging to correlate with histological examination. These data are useful to validate our system and to guide imaging follow-up for thermal ablation lesions in brain tissue from our therapy, tcMRgFUS, and LITT.

Magnetic resonance-guided interstitial high-intensity focused ultrasound for brain tumor ablation

Currently, treatment of brain tumors is limited to resection, chemotherapy, and radiotherapy. Thermal ablation has been recently explored. High-intensity focused ultrasound (HIFU) is being explored as an alternative. Specifically, the authors propose delivering HIFU internally to the tumor with an MRI-guided robotic assistant (MRgRA). The advantage of the authors' interstitial device over external MRI-guided HIFU (MRgHIFU) is that it allows for conformal, precise ablation and concurrent tissue sampling. The authors describe their workflow for MRgRA HIFU delivery.

Effect of labor analgesia on breastfeeding success

BACKGROUND

The effect of labor analgesia on breastfeeding success is not well defined. Some authors have hypothesized that labor analgesia may affect lactation success. The purpose of this observational study was to determine if intrapartum analgesia influenced breastfeeding success at 6 weeks postpartum in a setting that strongly supported breastfeeding.

METHODS

Healthy women with uncomplicated term pregnancies who planned to breastfeed consented to a telephone interview. We recorded demographic data, labor induction status, delivery mode, and analgesic medications. At between 6 and 8 weeks postpartum, patients were asked to describe breastfeeding use, problems encountered, solutions derived, sources of support and information, and satisfaction. We created a logistic regression model using intrapartum analgesia information and controlling for demographic factors previously correlated with lactation success.

RESULTS

We enrolled 189 women, contacted 177 women postpartum, and obtained complete data on 171 women. Of these, 59 percent received epidural analgesia, 72 percent breastfed fully, and 20 percent breastfed partially (> 50% of infant nutrition) at 6 weeks postpartum. After controlling for demographics and labor outcome, we could not demonstrate a correlation between breastfeeding success at 6 to 8 weeks and labor analgesia.

CONCLUSIONS

In a hospital that strongly promotes breastfeeding, epidural labor analgesia with local anesthetics and opioids does not impede breastfeeding success. We recommend that hospitals that find decreased lactation success in parturients receiving epidural analgesia reexamine their postdelivery care policies.