Peripheral nerve stimulation (PNS): A valid and definitive therapeutical option for a case of anterior cutaneous nerve entrapment syndrome (ACNES).

Anterior cutaneous nerve entrapment syndrome (ACNES) is a cause of moderate to severe chronic pain, hyperesthesia/hypoesthesia, and altered perception of heat/cold in a specific region of the anterior abdominal wall, referable to the territory of innervation of one or more anterior branches of the intercostal nerves. None of the therapeutic options currently available has proved to be effective in the long term or decisive. In recent years, we have begun to treat purely sensory neuropathies, such as this, with the implantation of wireless peripheral nerve stimulators (PNS), achieving the safety of modular and personalized analgesia. We report the case of a 41-year-old man suffering from ACNES of the 8th intercostal nerve for two years. We first performed two consecutive ultrasound-guided diagnostic blocks of the anterior cutaneous branch of the 8th intercostal right nerve and then elected the patient for ultrasound-guided nerve decompression followed by neuromodulation and pulsed-radiofrequency (PRF). Taking into account full employment, young age, and the likelihood of having to repeat the treatment several times, we considered him for Peripheral Nerve Stimulation (PNS) implantation under ultrasound guidance, and we implanted the wireless lead at the anterior branch of the right 8th intercostal nerve, and programmed tonic stimulation 100 Hz PW 200 ms. The patient reported immediate pain relief and never took medication for this problem again, at two years follow-up. PNS has had an increasing role in the management of chronic neuropathic pain, especially in merely sensitive neuropathies like ACNES. We support future research on this theme.

Combination Drug Therapy for the Management of Chronic Neuropathic Pain.

Chronic neuropathic pain (NP) is an increasingly prevalent disease and leading cause of disability which is challenging to treat. Several distinct classes of drugs are currently used for the treatment of chronic NP, but each drug targets only narrow components of the underlying pathophysiological mechanisms, bears limited efficacy, and comes with dose-limiting side effects. Multimodal therapies have been increasingly proposed as potential therapeutic approaches to target the multiple mechanisms underlying nociceptive transmission and modulation. However, while preclinical studies with combination therapies showed promise to improve efficacy over monotherapy, clinical trial data on their efficacy in specific populations are lacking and increased risk for adverse effects should be carefully considered. Drug-drug co-crystallization has emerged as an innovative pharmacological approach which can combine two or more different active pharmaceutical ingredients in a single crystal, optimizing pharmacokinetic and physicochemical characteristics of the native molecules, thus potentially capitalizing on the synergistic efficacy between classes of drugs while simplifying adherence and minimizing the risk of side effects by reducing the doses. In this work, we review the current pharmacological options for the treatment of chronic NP, focusing on combination therapies and their ongoing developing programs and highlighting the potential of co-crystals as novel approaches to chronic NP management.

Fast-Acting Sub-perception Spinal Cord Stimulation for a Case of Painful Diabetic Polyneuropathy. Just an Antalgic Treatment or Even a Therapy?

Introduction: Painful diabetic polyneuropathy (P-DPN) occurs in 20% - 30% of diabetic patients. Currently, therapeutic strategies include lifestyle modifications, good glycemic control, and neuropathic pain drugs. Spinal cord stimulation (SCS) has been shown to be successful in patients who have not responded to other treatments. The American Diabetes Association strongly recommends early screening and diagnosis for this condition through clinical tests and nerve conduction study (NCS). In recent years, high-resolution ultrasonography (HRUS) with the analysis of cross-sectional area (CSA) has shown an increasingly important role in detecting changes in the nervous structures, blood vessels, echo, and mobility of the nerve. Cross-sectional area is frequently enlarged in these patients, even those with normal NCS. We aimed to use SCS with fast-acting sub-perception therapy (FAST) modality to treat P-DPN. We also evaluated the CSA of the involved nerves before and after treatment. Case Presentation: A 58-year-old female patient was referred to our hospital in 2020 (Civitavecchia, Italy). She suffered from P-DPN for 3 years and did not respond to conventional medical treatments. Preoperative electromyography (EMG) was negative for radiculopathy, while electroneurography (ENG) showed a reduction in sensory conduction velocity (SCV) in the sural nerve (SN) bilaterally. Clinical tests on perceived pain and quality of life showed high severity. The report was confirmed by HRUS with enlargement of the CSA of the posterior tibial nerve (PTN), external popliteal nerve (EPN), and SN. The patient was successfully subjected to all-in-one SCS implantation in the FAST modality. She obtained immediate pain relief that remained unaltered at the 3-month follow-up. The patient completely discontinued drug therapy. One month after implantation, ENG highlighted an increased SN SCV, and the HRUS of PTN EPN and SN showed a significant reduction in CSA in all 3 nerves involved. Conclusions: Early diagnosis and treatment are crucial in improving the clinical outcome of P-DPN, but there is still no gold standard therapy. Spinal cord stimulation in the new FAST modality was effective in this clinical case. The pain relief was supported by a significant reduction in the CSA of the studied nerves observed on HRUS 1 month after SCS implantation. The results and the improvement of a pathological nervous pattern, albeit with a short follow-up of only 3 months, could suggest not only a symptomatic but perhaps also a therapeutic role of SCS in P-DPN.

The Role of Hypertonic Saline in Ablative Radiofrequency of the Sacroiliac Joint: Observational Study of 40 Patients.

BACKGROUND: The aim of this retrospective uncontrolled article is to illustrate a technique of neurotomy of the sensitive branches of S1 S2 S3 in RFA that appears to result in a better success rate and longer-lasting pain relief. METHODS: 40 patients were treated, 26 females and 14 males, with an average age of 74 (92-55). After the examination, the patients underwent an ultrasound-guided diagnostic block of the affected sacroiliac joint. Only patients who presented pain relief greater than 60% after the diagnostic block were candidates for the RFA procedure. The procedure was always performed in the operating room on an outpatient basis. After obtaining the best fluoroscopic visualization of the joint to be treated, two RFA cannulae were placed starting from the lower medial margin parallel to the SIJ to perform a bipolar RFA along the entire medial margin of the SIJ. Lidocaine 2% and hypertonic saline 2 mEq/mL were used for each RFA level. Patients were followed-up at 3, 6, 12, 18, and 24 months by evaluating the NRS and SF-12. RESULTS: Patients reported extreme satisfaction with the procedure performed and reported a significant improvement in NRS and SF-12 at FU visits. No adverse events occurred. CONCLUSIONS: Bipolar RFA treatment of the sacroiliac joint with the use of a hypertonic saline solution appears to improve the success of the method and its durability. We are inclined to believe that the use of hypertonic saline may significantly increase the lesion area and result in a greater effect on the sensory branches.

Peripheral Nerve Stimulation: Two Cases of Intractable Neuropathic Pain.

INTRODUCTION: Neuropathic pain can be caused by several pathologies affecting the nervous system. Peripheral neuralgias may be related to nerve entrapment, traumatic or iatrogenic events, and may also accompany many other diseases. Peripheral nerve stimulation is effective in treating many of these neuralgic syndromes. CASE PRESENTATION: We treated two patients suffering from chronic neuropathic pain of peripheral origin with the implantation of a Bioness (Valencia CA, USA) StimRouter® peripheral nerve stimulation system with follow-up visits at 1 - 3 - 6 - 12 months. CONCLUSIONS: PNS performed with the StimRouter® system, implanted percutaneously under ultrasound guidance, is safe and effective for patients.

Cadaveric Model Simulations for Training in Ultrasound-Guided Percutaneous Placement of a Novel Peripheral Nerve Stimulation Electrode.

Peripheral nerve stimulation (PNS) electrodes are used to treat intractable painful conditions involving peripheral nerves. Methods for performing PNS continue to evolve, from open surgical to minimally invasive placement of electrodes. A PNS system consisting of subcutaneously implanted leads with an integrated anchor and electrodes, and an external pulse generator to produce peripheral neuromodulation, is now available for use in the clinical setting. This novel system allows either surgical or percutaneous lead positioning, and avoids the use of long leads or extensions crossing the joints, which are exposed to mechanical stress and damage. To identify methods for successfully inserting these electrodes, we investigated if a cadaver model could be an effective educational tool for teaching PNS electrode placement using ultrasound guidance. Six cadavers were studied in an attempt to find an ideal approach for ultrasound-guided electrode placement into the upper and lower extremities and cervical spine, and to describe the unique anatomy of the peripheral nerves relative to percutaneous stimulation-electrode placement. The use of cadaveric model simulations offers opportunities to practice percutaneous placement of PNS electrodes under stress-free conditions without patient discomfort, to acquire skill and confidence in performing these surgical approaches. Ultrasound-guided percutaneous placement of PNS electrodes should be learned in a simulation laboratory before such placement is performed in actual patients.

Optical fiber technology enables smart needles for epidurals: an in-vivo swine study.

Nowadays, epidural space identification is made by using subjective and manual techniques characterized by failure rates up to 7%. In this work, we propose a fiber optic sensor technology based needle guidance system, that is directly inspired by the most common technique currently used for epidurals; through real-time strain measurements, the fiber Bragg grating integrated inside the needle lumen is able to effectively perceive the typical force drop occurring when the needle enters the epidural space. An in vivo swine study demonstrates the validity of our approach, paving the way for the development of lab-in-a-needle systems.

Smart Optical Catheters for Epidurals.

Placing the needle inside the epidural space for locoregional anesthesia is a challenging procedure, which even today is left to the expertise of the operator. Recently, we have demonstrated that the use of optically sensorized needles significantly improves the effectiveness of this procedure. Here, we propose an optimized configuration, where the optical fiber strain sensor is directly integrated inside the epidural catheter. The new design allows the solving of the biocompatibility issues and increases the versatility of the former configuration. Through an in vivo study carried out on a porcine model, we confirm the reliability of our approach, which also opens the way to catheter monitoring during insertion inside biological spaces.