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.

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.

What would surgeons like from materials scientists?

Surgery involves the repair, resection, replacement, or improvement of body parts and functions and in numerous ways, surgery should be considered human engineering. There are many areas in which surgical materials could be improved, but surgeons are generally unaware of materials available for use, while materials scientists do not know what surgeons require. This article will review some of the areas where surgeons and materials scientists have interacted in the past and will discuss some of the most pressing problems which remain to be solved. These include better implant materials for hernia repair, breast reconstruction, the treatment of diabetes, vascular stenting and reconstruction, and electrical pacing devices. The combination of tissue engineering and nanomaterials has great potential for application to nearly every aspect of surgery. Tissue engineering will allow cells or artificial organs to be grown for specific uses while nanotechnology will help to ensure maximal biocompatibility. Biosensors will be combined with improved electrodes and pacing devices to control impaired neurological functions.