Improved Pain Control with Combination Spinal Cord Stimulator Therapy Utilizing Sub-perception and Traditional Paresthesia Based Waveforms: A Pilot Study.

BACKGROUND: Chronic back and neck pain affects 20% of Americans. Spinal cord stimulation (SCS) is an effective therapy for otherwise refractory chronic pain. Traditional SCS relies on low-frequency stimulus in the 40 - 60 Hz range causing robust paresthesia in regions overlapping with painful dermatomes. OBJECTIVES: This study aims to determine the effect of superimposing sub-perception stimulation in patients who previously had good long-term relief with paresthesia. METHODS: This is a prospective observational trial examining patients who had previously been implanted with paresthesia based SCS for failed back surgery syndrome (FBSS) or complex regional pain syndrome (CRPS). These patients presented for implantable pulse generator (IPG) replacement based on battery depletion with an IPG capable of combined sub-perception and paresthesia based SCS therapy. Patients were assessed immediately following the exchange and four weeks later using a telephone survey. Their pain was assessed on each follow up using a Numerical Rating scale (NRS); the primary outcome was the change in NRS after four weeks from the exchange day. Secondary outcomes included paresthesia changes, which included the subjective quality of sensation generated, the overall subjective coverage of the painful region, subjective variation of coverage with positional changes, and global perception of the percentage improvement in pain. RESULTS: Based on our clinic registry, 30 patients were eligible for IPG exchange, 16 were consented for follow up and underwent an exchange, and 15 were available for follow up four weeks following. The average NRS decreased from 7.47 with traditional SCS to 4.5 with combination therapy. 80% of patients reported an improvement in the quality of paresthesia over traditional SCS therapy, and in most patients, this translated to significantly improved pain control. CONCLUSIONS: Our findings suggest improved pain relief in patients who had previously had good results with paresthesia based therapy and subsequently underwent IPG exchange to a device capable of delivering combined sub-perception stimulation. The mechanism of action is unclear though there may be an additive and/or synergistic effect of the two waveforms delivered. Larger studies with long-term follow-up are needed to elucidate the durability of pain relief and the precise mechanism by which combined subperception and paresthesia based SCS may improve overall patient outcomes.

Emergency preparedness for public health threats, surveillance, modelling & forecasting.

In the interconnected world, safeguarding global health security is vital for maintaining public health and economic upliftment of any nation. Emergency preparedness is considered as the key to control the emerging public health challenges at both national as well as international levels. Further, the predictive information systems based on routine surveillance, disease modelling and forecasting play a pivotal role in both policy building and community participation to detect, prevent and respond to potential health threats. Therefore, reliable and timely forecasts of these untoward events could mobilize swift and effective public health responses and mitigation efforts. The present review focuses on the various aspects of emergency preparedness with special emphasis on public health surveillance, epidemiological modelling and capacity building approaches. Global coordination and capacity building, funding and commitment at the national and international levels, under the One Health framework, are crucial in combating global public health threats in a holistic manner.

Cannabis Use in Hospitalized Patients with Chronic Pain.

INTRODUCTION: To date, no study has reported the prevalence of cannabis use in chronic pain patients. The aim of this study is to investigate the trends in cannabis use among chronic pain in-patients from 2011 to 2015 in the USA. METHODS: Patients were identified from the National Inpatient Sample (NIS) database using the International Classification of Diseases, Ninth and Tenth Revision, diagnosis codes for chronic pain and cannabis use. Annual estimates and trends were determined for cannabis use, patient characteristics, cannabis use among subgroups of chronic pain conditions, cost, length of stay, and associated discharge diagnosis. RESULTS: Between 2011 to 2015, a total of 247,949 chronic pain patients were cannabis users, increasing from 33,189 to 72,115 (P < 0.001). There were upward trends of cannabis use in females (38.7-40.7%; P = 0.03), Medicare insured patients (32.7-40.4%; P < 0.01), patients with lowest annual household income (36.1-40.9%; P = 0.02), patients aged 45-64 years (45.9-49.2%; P < 0.001), and patients with tobacco use disorder (63.8-72.4%; P < 0.0001). Concurrently, cannabis use decreased among patients with opioid use disorder (23.8-19.9%; P < 0.001). Cannabis use increased from 2011 to 2015 in patients with chronic regional pain syndrome, trauma, spondylosis, and failed back surgery syndrome. Adjusted total hospitalization cost increased from $31,271 ($1333) in 2011 to $38,684 ($946) in 2015 (P < 0.001). CONCLUSIONS: Cannabis use increased substantially from 2011 to 2015, while the rates of cannabis use in opioid users down-trended simultaneously. Disparities in cannabis use among subgroups should be explored further.

A Temporary vs. Permanent Anchored Percutaneous Lead Trial of Spinal Cord Stimulation: A Comparison of Patient Outcomes and Adverse Events.

OBJECTIVES: A trial of spinal cord stimulation (SCS) is a prerequisite to determine efficacy of the therapy prior to placement of a permanent implanted system. A trial may be conducted employing a percutaneously placed temporary cylindrical lead or via a permanently anchored cylindrical lead placed and subsequently secured via open surgical method. There has been little investigation comparing the two methods of trial. This study is a comparative analysis of the two methods both for prediction of success as well as associated morbidity. STUDY DESIGN: Retrospective chart review. MATERIALS AND METHODS: SCS outcomes of percutaneous temporary lead trial or the temporary lead (TL) group and permanent anchored lead trial or permanent lead (PL) group were analyzed for lack of relief, poor paresthesia coverage, false positive trial phase, fading relief, and biological complications. RESULTS: Outcome data was analyzed for 148 patients in the TL group and 138 patients in the PL group. In comparing the two trial methods, false positive rate of trial was higher (p < 0.05) in the PL group as compared to the TL group (6.35 vs. 1.35%). Cumulative wound infections (6.52 vs. 1.35%), and poor wound healing (4.35 vs. 0%) were also significantly higher in the PL group. Rate of success in the trial phase was equal in both groups. CONCLUSION: The percutaneous temporary lead trial group was associated with fewer false positives and wound related complications as compared to permanent anchored lead trial group. There was very little technical advantage of routinely anchoring the trial lead.

Magnetic resonance imaging of the lumbar spine in a patient with a spinal cord stimulator.

BACKGROUND: The use of magnetic resonance imaging (MRI) is continuously escalating for the evaluation of patients with persistent pain following lumbar spine surgery (LSS). Spinal cord stimulation (SCS) therapy is being clinically applied much more commonly for the management of chronic pain following LSS. There is an increased probability that these 2 incompatible modalities may be accidentally used in the same patient. OBJECTIVES: The purpose of this case report is to: (1) summarize a case in which a patient with a thoracic spinal cord stimulator underwent a diagnostic lumbar MRI, (2) describe the 3 magnetic fields used to generate images and their interactions with SCS devices, and (3) summarize the present literature. STUDY DESIGN: Case report. SETTING: University hospital. RESULTS: Aside from mild heat sensations in the generator/pocket site and very low intensity shocking sensations in the back while in the MRI scanner, the patient emerged from the study with no clinically detected adverse events. Subsequent activation of the SCS device would result in a brief intense shocking sensation. This persisted whenever the device was activated and required Implantable Pulse Generator (IPG) replacement. Electrical analysis revealed that some of the output circuitry switches, which regulate IPG stimulation and capacitor charge balancing, were damaged, most likely by MRI radiofrequency injected current. LIMITATIONS: Single case of a patient with a thoracic SCS having a lumbar MRI study. CONCLUSION: This case demonstrates the lack of compatibility of lumbar MRI and the Precision SCS system as well as one of the possible patient adverse events that can occur when patients are exposed to MRI outside of the approved device labeling.