Peripheral Nerve Stimulation in the Treatment of Chronic Pain Syndromes From Nerve Injury: A Multicenter Observational Study.

INTRODUCTION: Assessing the feasibility, technical implications, and clinical benefits of peripheral nerve stimulation (PNS) performed by an implantable pulse generator (IPG) located close to the stimulation site. MATERIALS AND METHODS: Selected patients were affected by neuropathic pain associated with a documented peripheral nerve lesion, refractory to conventional surgical or pharmacological treatment. A PNS system specifically designed for peripheral placement (Neurimpulse, Padova, Italy) was implanted and followed for six months, recording the degree of patient's satisfaction (PGI-I questionnaire), the pain numerical rating scale (NRS) and the quality of life (SF36 questionnaire), as well as any change in drug regimen and work capability. The statistical significance of differences was determined by the paired Student's t-test. RESULTS: A total of 58 patients were referred to permanent IPG implantation. Stimulation failure due to lead damage or dislocation was noticed in two cases (3.4%) in six months. At the follow-up end, the relative NRS reduction averaged -58 ± 30% (p < 10-6 ) and was greater than 50% in 69% of the cases. Quality-of-life physical and mental indices were increased by 18% (p < 0.005) and 29% (p < 0.0005), respectively. The administration of antalgic drugs was stopped in 55% and reduced in 16% of the patients. Low-energy stimulation was possible in most cases, resulting in an IPG estimated life of 80 ± 35 months. CONCLUSIONS: Successful PNS was achieved with a stimulation system designed for peripheral location. This new technology reduced the incidence of lead-related adverse events and the energy cost of the treatment.

Pulsed Radiofrequency Therapy at Different Voltages on Dorsal Root Ganglia Using Multifunctional Catheter to Treat Low Back Pain: A Comparative Retrospective Study.

BACKGROUND: Applying pulsed radiofrequency (PRF) to the dorsal root ganglion (DRG) is an electrical neuromodulation technique, a valid complementary therapeutic treatment for failed back surgery syndrome (FBBS). Peridurolysis, when applied to vertebral canal adhesions, can be performed with dedicated catheters, providing patients with the benefits of mechanical, electrical, and pharmacological techniques. OBJECTIVES: The aim of this study was to evaluate PRF's effects on the DRG as part of FBSS treatment at different follow-up times, comparing 2 groups of patients exposed to distinct levels of voltage (100 V vs. 45 V) from a PRF generator. STUDY DESIGN: A retrospective observational study was performed. SETTING: The study was conducted on a sample of patients from an Italian hospital. METHODS: PRF's effects on the DRG as part of FBSS treatment were evaluated through the Numeric Rating Scale (NRS) and the monitoring of 155 patients' opioid consumption at 3, 6, and 9 months. A Cosman® G4 model PRF generator was used. During follow-up periods, the Friedman test was applied to detect differences in outcomes between the 2 groups of patients, who were treated with different levels of voltage. RESULTS: The most frequent diagnosis (61.29%) was FBBS in patients at a mean age of 64 (± 11.8) years old. All patients were treated with PRF on the dorsal ganglion, with the addition of a drug mixture. Most were treated with 100 V (62%). A statistically significant decrease (P < 0.001) in the NRS score emerged both as a whole and in the 2 distinct groups. Moreover, the group of 100 V patients showed a significant (P = 0.0360) reduction in the use of opioids. LIMITATIONS: This observational retrospective study was based on a convenience sampling that involved a limited number of patients. CONCLUSIONS: E-field technology is the only way to generate a constant 38°/42° PRF and 100 V level throughout surgical interventions (respecting the exposure times "set" by the operator). The patient will not feel any pain or electric current because the generated milliamperes will be greatly reduced.

A Novel Mini-invasive Approach to the Treatment of Neuropathic Pain: The PENS Study.

BACKGROUND: Peripheral neuromodulation is often used as chronic neuropathic pain treatment. Percutaneous electrical nerve stimulation (PENS) is generally utilized with several probes at the same time and repeated treatments. OBJECTIVES: Evaluate the short- and long-term efficacy of a single probe and single shot PENS approach. STUDY DESIGN: Multicenter, prospective, observational study. SETTING: Four Italian pain therapy centers. METHODS: Inclusion criteria were age = 18 and = 80 years, presence of severe peripheral neuropathic pain lasting more than 3 months, localized and refractory to pharmacological therapies. Patients with infection, coagulopathies, psychiatric disorders, pacemakers, or implantable cardiac defibrillators were excluded. PATIENTS: Seventy-six patients (47 women, 29 men), mean age 62 ± 14 years, affected by neuralgia (21 herpes zoster infection, 31 causalgia, 24 postoperative pain) were enrolled in the study. INTERVENTION: After localization of trigger point and/or allodynic/hyperalgesic area, PENS therapy was achieved with a single 21 gauge conductive probe tunneled percutaneously and a neurostimulator device. MEASUREMENT: Numerical Rating Scale (NRS) and Neuropathic Pain Scale (NPS) were assessed at baseline, 60 minutes after PENS, at one week, after one, 3, and 6 months; perceived health outcome was measured with Euroqol-5 dimension (EQ-5D) questionnaire at baseline and at 6 months. Adverse events and patient satisfaction were reported. RESULTS: NRS and NPS decreased significantly after 60 minutes and the reduction remained constant over time at follow-up. EQ-5D increased significantly with respect to the baseline. Two nonclinically significant adverse events (one contralateral dysestesia and one self-resolving hematoma) were observed. LIMITATIONS: Small sample size and non-randomized observational study; high prevalence of post-herpetic and occipital neuralgias. CONCLUSION: PENS therapy produced significant and long-lasting pain relief in chronic peripheral neuropathic pains of different etiology. The present study confirms the feasibility, safety, and repeatability of this minimally invasive technique.