A Feasibility Study of Percutaneous Peripheral Nerve Stimulation for the Treatment of Postoperative Pain Following Total Knee Arthroplasty.

INTRODUCTION: The objective of the present feasibility study was to investigate the use of a new treatment modality-percutaneous peripheral nerve stimulation (PNS)-in controlling the often severe and long-lasting pain following total knee arthroplasty (TKA). METHODS: For patients undergoing a primary, unilateral TKA, both femoral and sciatic open-coil percutaneous leads (SPR Therapeutics, Cleveland, OH) were placed up to seven days prior to surgery using ultrasound guidance. The leads were connected to external stimulators and used both at home and in the hospital for up to six weeks total. RESULTS: In six of seven subjects (86%), the average of daily pain scores across the first two weeks was <4 on the 0-10 Numeric Rating Scale for pain. A majority of subjects (four out of seven; 57%) had ceased opioid use within the first week (median time to opioid cessation for all subjects was six days). Gross sensory/motor function was maintained during stimulation, enabling stimulation during physical therapy and activities of daily living. At 12 weeks following surgery, six of seven subjects had improved by >10% on the Six-Minute Walk Test compared to preoperative levels, and WOMAC scores improved by an average of 85% compared to before surgery. No falls, motor block, or lead infections were reported. CONCLUSIONS: This feasibility study suggests that for TKA, ultrasound-guided percutaneous PNS is feasible in the immediate perioperative period and may provide analgesia without the undesirable systemic effects of opioids or quadriceps weakness induced by local anesthetics-based peripheral nerve blocks.

Ultrasound-Guided Percutaneous Peripheral Nerve Stimulation: Neuromodulation of the Femoral Nerve for Postoperative Analgesia Following Ambulatory Anterior Cruciate Ligament Reconstruction: A Proof of Concept Study.

OBJECTIVES: The purpose of this prospective proof of concept study was to investigate the feasibility of using percutaneous peripheral nerve stimulation of the femoral nerve to treat pain in the immediate postoperative period following ambulatory anterior cruciate ligament reconstruction with a patellar autograft. MATERIALS AND METHODS: Preoperatively, an electrical lead (SPRINT, SPR Therapeutics, Inc., Cleveland, OH, USA) was percutaneously implanted with ultrasound guidance anterior to the femoral nerve caudad to the inguinal crease. Within the recovery room, subjects received 5 min of either stimulation or sham in a randomized, double-masked fashion followed by a 5-min crossover period, and then continuous active stimulation until lead removal postoperative Day 14-28. Statistics were not applied to the data due to the small sample size of this feasibility study. RESULTS: During the initial 5-min treatment period, subjects randomized to stimulation (n = 5) experienced a slight downward trajectory (decrease of 7%) in their pain over the 5 min of treatment, while those receiving sham (n = 5) reported a slight upward trajectory (increase of 4%) until their subsequent 5-min stimulation crossover, during which time they also experienced a slight downward trajectory (decrease of 11% from baseline). A majority of subjects (80%) used a continuous adductor canal nerve block for rescue analgesia (in addition to stimulation) during postoperative Days 1-3, after which the median resting and dynamic pain scores remained equal or less than 1.5 on the numeric rating scale, respectively, and the median daily opioid consumption was less than 1.0 tablet. CONCLUSIONS: This proof of concept study demonstrates that percutaneous femoral nerve stimulation is feasible for ambulatory knee surgery; and suggests that this modality may be effective in providing analgesia and decreasing opioid requirements following anterior cruciate ligament reconstruction. clinicaltrials.gov: NCT02898103.

The Use of Spinal Cord Stimulation/Neuromodulation in the Management of Chronic Pain.

Chronic pain causes a tremendous burden on the society in terms of economic factors and social costs. Rates of spinal surgery, especially spinal fusion, have increased exponentially over the past decade. The opioid epidemic in the United States has been one response to the management of pain, but it has been fraught with numerous catastrophic-related adverse effects. Clinically, spinal cord stimulation (SCS)/neuromodulation has been used in the management of chronic pain (especially spine-related pain) for more than two decades. More recent advances in this field have led to new theories and approaches in which SCS can be used in the management of chronic spine-related pain with precision and efficacy while minimizing adverse effects commonly seen with other forms of chronic pain treatment (eg, narcotics, injections, ablations). Narcotic medications have adverse effects of habituation, nausea, constipation, and the like. Injections sometimes lack efficacy and can have only limited duration of efficacy. Also, they can have adverse effects of cerebrospinal fluid leak, infection, and so on. Ablations can be associated with burning discomfort, lack of efficacy, recurrent symptoms, and infection. High-frequency stimulation, burst stimulation, tonic stimulation with broader paddles, and new stimulation targets such as the dorsal root ganglion hold promise for improved pain management via neuromodulation moving forward. Although a significant rate of complications with SCS technology are well described, this can be a useful tool in the management of chronic spine-related pain.

Needleless Transcutaneous Neuromodulation Accelerates Postoperative Recovery Mediated via Autonomic and Immuno-Cytokine Mechanisms in Patients With Cholecystolithiasis.

BACKGROUND: Postsurgical gastrointestinal disturbance is clinically characterized by the delayed passage of flatus and stool, delayed resumption of oral feeding, dyspepsia symptoms, and postsurgical pain. This study was designed 1) to evaluate the effects of needleless transcutaneous neuromodulation (TN) on postoperative recovery; 2) to investigate mechanisms of the TN involving autonomic functions in postoperative patients after removal of the gallbladder. METHODS: Sixty patients scheduled for laparoscopic cholecystectomy (LC) were randomized to TN (n = 30) and sham-TN (n = 30). TN was performed via acupoints ST36 and PC6 for 30 min twice daily from 24 hours before surgery to 72 hours after surgery. Sham-TN was performed using the same parameters at nonacupoints. RESULTS: 1) Compared to sham-TN, TN shortened time to first flatulence (38.9 ± 4.0 vs. 24.9 ± 2.4 hour, p = 0.004) and time to defecation (63.1 ± 4.5 vs. 42.5 ± 3.1 hour, p < 0.001). 2) Compared to sham-TN, TN increased the percentage of normal pace-making activity (66.2 ± 2.2 vs. 73.8 ± 2.3%, p = 0.018). 3) TN enhanced vagal activity. Compared to that 24 hours before surgery, surgery decreased vagal activity (HF) (0.41 ± 0.02 vs. 0.34 ± 0.02, p = 0.043) 3 hours after the operation. Compared to sham-TN, TN increased HF (0.45 ± 0.02 vs. 0.52 ± 0.02, p = 0.045) 72 hours after the operation. Further, HF was negatively correlated with time to defecation and serum norepinephrine. 4) Surgery increased serum IL-6 (1.1 ± 0.1 before surgery vs. 2.9 ± 0.7 pg/mL, p = 0.041) 72 hours after the operation, which was reduced to baseline by TN (0.9 ± 0.1). CONCLUSIONS: In conclusion, the proposed needleless TN accelerates postoperative recovery after LC, possibly mediated via the autonomic and immune-cytokine mechanisms. Needleless and self-administrable TN may be an easy-to-implement and low-cost complementary therapy for postoperative recovery.

A Retrospective Analysis of 25 Cases With Peripheral Nerve Field Stimulation for Chronic Low Back Pain and the Predictive Value of Transcutaneous Electrical Nerve Stimulation for Patient Selection.

OBJECTIVE: Transcutaneous electrical nerve stimulation (TENS) and peripheral nerve field stimulation (PNFS) may be proposed to patients with chronic lumbar pain refractory to conventional treatment. Aim of this study was to assess the importance of preoperatively treatment with TENS as a predictive value for later successful PNFS and impact of PNFS in follow-up of 12 months. METHODS: Between 2012 and 2016, a retrospective analysis of 25 patients with chronic lumbar pain and implantation of a PNFS-system was performed. Pain intensity (NRS), health-related quality of life (EQ-5D-5L), Oswestry disability index (ODI), actual mood state scale (ASTS), and treatment satisfaction (CSQ-8) were assessed pre/postoperatively, after 6 and 12 months. TENS use before surgery was assessed. RESULTS: The cohort consisted of 25 patients with a median age of 56 years (IQR25-75 51-63). In a subgroup analysis, 18 patients used TENS before surgery, 7 did not use TENS and were excluded. No pain relief was observed in 14 patients. Ten of these patients showed later positive effect in PNFS trial stimulation. In four patients, pain relief with TENS was seen. One patient later on had no benefit after PNFS trial, three had sufficient pain relief. In the whole cohort, five patients had no benefit after PNFS trial, in 20 patients a neurostimulator was implanted. NRS, EQ-5D-5L, and ODI measures showed significant improvement in the whole follow-up after PNFS implantation. ASTS scale showed an increase of values for positive mood and a reduction in values for sorrow, fatigue, and anger. In 55%, a sustained reduction in demand for analgesics was seen after 6 months, 50% after 12 months, respectively. CONCLUSION: In this retrospective analysis, TENS has no predictive value in the selection of patients with low back pain for the PFNS treatment. PNFS is effective and safe to relieve significantly symptoms of chronic low back pain.

Pocket Pain and Neuromodulation: Negligible or Neglected?

OBJECTIVES: Pain encountered at the site of the implantable pulse generator (IPG) after invasive neuromodulation is a well-known and important complication. The reported incidence of implant site pain is variable, ranging between 0.4 and 35%. Implant site pain has never been systematically studied and no treatment guidelines are available. MATERIAL AND METHODS: We performed an observational study (study registration number mp05728) on the incidence and the determining factors of implant site pain, the subjective rating of intensity by sending questionnaires (n = 554) to our cohort of neuromodulation patients with IPGs. The number of revision surgeries and explants due to implant site pain were also analyzed. RESULTS: Total response rate was 50% (n = 278). Pain patients suffered significantly (p < 0.05) more often from IPG site pain than other patients undergoing neuromodulation therapies. Up to 64% of patients undergoing spinal cord stimulation reported IPG site discomfort or pain. Severe pocket pain was found in up to 8% of patients. No association was found between other variables (age, BMI, duration of follow-up, gender, smoking, number of pocket surgeries) and implant site pain. CONCLUSION: Pocket pain represents an important problem after invasive neuromodulation and is more prevalent in pain patients. We believe further technological improvements with miniaturized IPGs will impact the incidence of pocket pain and could even obviate the need for an IPG pocket.

Effect of Nerve Stimulation Use on the Success Rate of Ultrasound-Guided Subsartorial Saphenous Nerve Block: A Randomized Controlled Trial.

BACKGROUND AND OBJECTIVES: Ultrasound-guided subsartorial saphenous nerve block is commonly used to provide complete surgical anesthesia of the foot and ankle in combination with a popliteal sciatic nerve block. However, in part owing to its small caliber and absence of a prominent vascular landmark in the subsartorial plane distal to the adductor canal, the saphenous nerve is more difficult to reliably block than the sciatic nerve in the popliteal fossa. Although the saphenous nerve is a sensory nerve only, neurostimulation can be used to elicit a "tapping" sensation on the anteromedial aspect of the lower leg extending toward the medial malleolus. Our objective was to test the hypothesis that the addition of nerve stimulation use to an ultrasound (US)-guided technique will increase the success rate of subsartorial saphenous nerve block. METHODS: With institutional human ethics board approval and participants' written informed consent, we enrolled 80 patients undergoing foot and ankle surgery in a randomized, single-blinded, parallel-group clinical trial. Patients were randomly assigned to receive US-guided subsartorial saphenous nerve block either alone (US group) or with the use of additional nerve stimulation (NS group; time limit, 5 minutes). For saphenous nerve blockade, all patients received 10 mL of 0.5% ropivacaine. The primary end point was complete absence of sensation to pinprick at 30 minutes at two different anatomic areas in the distribution of the saphenous nerve (2 cm proximal to the medial malleolus and 10 cm distal to the medial tibial condyle). Secondary end points included decreased sensation at 30 minutes and block failure (normal sensation) at 30 minutes. This trial was registered at ClinicalTrials.gov: NCT02382744. RESULTS: All 80 patients completed the trial (40 patients in each group). Twenty-two patients (55%) in the NS group versus 18 (45%) in the US group had complete absence of sensation to pinprick at 30 minutes at both anatomic areas of assessment (Fisher exact test, P = 0.25 [one sided]; 95% confidence interval of difference in proportions, -11.9% to 31.9%). The percentages of patients with any evidence of block (decreased or complete absence of sensation) at both areas at 30 minutes were 92.5% (NS) and 97.5% (US), respectively (P = 0.62 [two sided]); corresponding failure rates (normal sensation) were 7.5% (NS) and 2.5% (US). In the NS group, no response in the saphenous nerve distribution was elicited within 5 minutes of stimulation time limit in 20% of patients (n = 8). All of the patients in the NS group with normal sensation at 30 minutes (n = 3) were among this subcohort. CONCLUSIONS: The addition of the use of nerve stimulation did not improve the success rate of US-guided subsartorial saphenous nerve block. However, in the NS group, an inability to elicit a "tapping" sensation in the saphenous nerve distribution was associated with block failure.

Interventional procedures and future drug therapy for hypertension.

Hypertension management poses a major challenge to clinicians globally once non-drug (lifestyle) measures have failed to control blood pressure (BP). Although drug treatment strategies to lower BP are well described, poor control rates of hypertension, even in the first world, suggest that more needs to be done to surmount the problem. A major issue is non-adherence to antihypertensive drugs, which is caused in part by drug intolerance due to side effects. More effective antihypertensive drugs are therefore required which have excellent tolerability and safety profiles in addition to being efficacious. For those patients who either do not tolerate or wish to take medication for hypertension or in whom BP control is not attained despite multiple antihypertensives, a novel class of interventional procedures to manage hypertension has emerged. While most of these target various aspects of the sympathetic nervous system regulation of BP, an additional procedure is now available, which addresses mechanical aspects of the circulation. Most of these new devices are supported by early and encouraging evidence for both safety and efficacy, although it is clear that more rigorous randomized controlled trial data will be essential before any of the technologies can be adopted as a standard of care.

Technology for Peripheral Nerve Stimulation.

Peripheral nerve stimulation (PNS) has been in use for over 50 years to treat patients suffering from chronic pain who have failed conservative treatments. Despite this long history, the devices being used have changed very little. In fact, current PNS technology was developed specifically for spinal cord stimulation. The use of technology developed for other applications in PNS has led to an unnecessary number of device complications and the limited adoption of this promising therapy. The following chapter provides an overview of PNS technology throughout the years, outlining both the benefits and limitations. We will briefly explore the electrophysiology of PNS stimulation, with an emphasis on technology and indication-specific devices. Finally, design and technical requirements of an ideal PNS device will be discussed.

[Chronic pelvic pain syndrome: neurostimulation, neuromodulation and acupuncture]. / Chronisches Schmerzsyndrom des Beckens : Neurostimulation, Neuromodulation und Akupunktur.

Chronic pelvic pain syndrome (CPPS) is defined by the European Association of Urology guidelines as a non-malignant pain perceived in structures related to the pelvis of either women or men for at least 6 months without proven infection or other obvious pathology. It affects the quality of life of millions of people worldwide and has an impact similar to that reported for other chronic diseases, such as diabetes mellitus, Crohn's disease and congestive heart failure. The treatment of CPPS remains a challenge despite several established first line therapies because many patients are therapy refractory. Unconventional treatments, such as neurostimulation, neuromodulation and acupuncture may be highly successful for treating CPPS and have a favorable adverse event profile. Thus, these promising therapeutic alternatives should be considered more often in daily clinical practice.

The effect of TENS on pain, function, depression, and analgesic consumption in the early postoperative period with spinal surgery patients.

AIM: The aim of our study was to examine the effects of the use of Transcutaneous Electrical Nerve Stimulation (TENS) in patients who had undergone spinal surgery on pain, functionality, depression and consumption of analgesic agents. MATERIAL AND METHODS: Fifty-Four patients were randomized and placed into two groups, patient-controlled analgesia (PCA) plus TENS and only PCA. To assess the pain levels of the patients, the Visual Analog Scale (VAS) was used. In the assessment of their functional levels, the Timed Up and Go test (TUG) was utilized and in the assessment of their depression, the Beck Depression Inventory (BDI) was used. The measurements were performed before the operation and on the first and second postoperative days. The side effects were recorded from the analgesic agents. RESULTS: During the first and second days after the operation, a decrease in the pain levels was noticed in the TENS group (p < 0.05. In the TENS group, the consumption of analgesic agents also decreased and thus side effects were less frequent. From the viewpoint of functional and depression levels, no significant difference between the groups was noticed (p > 0.05). CONCLUSION: TENS was effective in reducing analgesic agent-related side effects and in reducing analgesic consumption. In addition, TENS also decreased activity related pain.

Peripheral nerve stimulation for fibromyalgia.

Fibromyalgia is a condition marked by widespread chronic pain, accompanied by a variety of other symptoms, including sleep and fatigue disorders, headaches, disorders of the autonomic nervous system, as well as cognitive and psychiatric symptoms. It occurs predominantly in women and is often associated with other systemic or autoimmune diseases. Despite its serious socio economical burden, the treatment options remain poor. In this chapter, the authors discuss the possibilities of using greater occipital nerve stimulation as a treatment for fibromyalgia, based on available clinical studies. Greater occipital nerve stimulation has already been used successfully to treat occipital neuralgia and various primary headache syndromes. Testable hypothetical working mechanisms are proposed to explain the surprising effect of this treatment on widespread bodily pain.

The future of peripheral nerve stimulation.

The field of peripheral nerve stimulation (PNS) is now experiencing a phase of rapid growth in number of patients, number of implanters, number of indications, and procedure types. This, however, appears to be only a beginning of major developments that could revolutionize the field of PNS. It is expected that the progress in PNS will continue simultaneously in several directions as new indications, new stimulation targets and new device designs evolve in the foreseeable future. Responding to a major need for safe and effective pain treatments and following a general trend toward less-invasive and nondestructive interventions, PNS has the potential of becoming a premier pain-relieving modality that will be used instead of or in combination with existing more established approaches such as spinal cord stimulation and pharmacological pain control. Recent technological advancements are cause for considerable optimism regarding the development of PNS and are likely to be a beginning of a major overhaul in our perception of PNS approaches. Expanding the number of applications will without question strengthen the field of PNS. The turning point, however, will not occur until sufficient scientific evidence is gathered to unequivocally prove its safety, clinical efficacy and cost-effectiveness, and when PNS applications become officially endorsed through regulatory approval of each indication. Such changes will allow implanters to use approved devices for approved indications--instead of the contemporary 'off-label' use--and at the same time give device manufacturers a chance to market these devices and support education on their appropriate use.

Intraoperative motor evoked potential monitoring: overview and update.

Amidst controversy about methodology and safety, intraoperative neurophysiology has entered a new era of increasingly routine transcranial and direct electrical brain stimulation for motor evoked potential (MEP) monitoring. Based on literature review and illustrative clinical experience, this tutorial aims to present a balanced overview for experienced practitioners, surgeons and anesthesiologists as well as those new to the field. It details the physiologic basis, indications and methodology of current MEP monitoring techniques, evaluates their safety, explores interpretive controversies and outlines some applications and results, including aortic aneurysm, intramedullary spinal cord tumor, spinal deformity, posterior fossa tumor, intracranial aneurysm and peri-rolandic brain surgeries. The many advances in motor system assessment achieved in the last two decades undoubtedly improve monitoring efficacy without unduly compromising safety. Future studies and experience will likely clarify existing controversies and bring further advances.

Electroanalgesia en el síndrome de dolor lumbar agudo: efectividad comparativa de TIF versus TENS: estudio preliminar / Electro-analgesia in the low back pain syndrome: comparative effectiveness of TIF versus TENS: preliminary study

Introduction: Low back pain (LBP) is a prevalent condition, which causes an important economic and clinical impact to individuals during their productive work-life. Electro-anaesthesia methods of choice are Interferential Current (IC) and transcutaneous Electric Nervous Stimulation (TENS). The objetive of this study is to determine the effectiveness of both therapies, as well as variability in the measurement of pain. We also preliminary evaluate the comparative effectiveness of IC and TENS by determining the mean difference of decreased acute back pain in patients treated at Hospital of Trabajador, in Temuco, Chile. Material and Method: 30 LBP patients were studied (0-3 weeks evolution). Intensity of pain before and after the aplication of IC and TENS was assessed usin the Visual Analogue Scale (VAS). IC intervention considered an amploitude.frequency spectrum ranging from 5 Hz to 10 Hz, with vector, while TENS was an asymmetric biphasic stimulus with a phase time of 150 useg, using a frequency of 100 Hz, pulses of 2 Hz. These were applied using four rubber electrodes (60 mm by 40 mm) placed on the lumbar zone for a period of 30 minutes. Results: The study group included 67 por ciento (n = 20) male with an average age of 38.3 years (SD: 9.5 years), 67 por ciento of them were workmen. The reduction of pain mean difference in patients treated with TENS was 1.24 cm (p = 0005), and 2.18 cm (p = 0001) with IC. The difference of both results, adjusted by VAS baseline, age, sex, and occupation of patients was 0.91 cm (p = 0.0261) in favour of IC. Conclusions: The magnitude of treatment effects for TENS was 18.4 por ciento, and 31.5 por ciento for IC in relation to baseline pain. In this study group, there were no clinically relevant differences to control LBP in patients inmediately after application, between IC and TENS. Both demonstrated to be effective.

Devices in the treatment of epilepsy.

The goal of the treatment of epilepsy is to eliminate seizures while causing no side effects. For persons whose seizures are refractory, epilepsy surgery may be an option. In addition, these patients may benefit from the vagus nerve stimulator (VNS), the first device approved for the treatment of refractory epilepsy. Although VNS was the first to be approved, investigators have been interested in the effectiveness of stimulating other brain regions: the cerebellum, thalamus, subthalamic nucleus, and locus coeruleus are a few examples. These studies have produced mixed results. As our understanding of the underlying mechanisms of epilepsy grows, it is likely that we will design better and more effective devices for the treatment of epilepsy.