Progress in neurological surgery
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Peripheral nerve stimulation (PNS) generally refers to stimulation of a named nerve via direct placement of a lead next to the nerve either via a percutaneous or open approach; in peripheral nerve field stimulation (PNFS), leads are subcutaneously placed to stimulate the region of affected nerves, cutaneous afferents, or the dermatomal distribution of the nerves which converge back to the spinal cord. Recently, there has been a renewed interest in using the PNS approach for many otherwise refractory pain conditions; however, PNFS appears to be more effective for the management of low back pain and therefore more attractive. ⋯ Our experience and the published studies provide evidence that PNFS is a safe and well-tolerated pain control option for intractable pain conditions, including chronic low back pain. Notably, achieving efficacious pain relief relies on correct patient selection and the optimal placement of the leads, ensuring, in particular, a lead depth of 10-12 mm from the surface to maximize the target sensation (mediated by fast-adapting Aβ fibers) of PNFS, which is believed to be most effective for the pain relief.
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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 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.
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Occipital nerve stimulation (ONS) continues to be investigated for the treatment of refractory chronic migraine. Results from case series and from prospective, sham-controlled clinical trials remain inconclusive regarding the efficacy of ONS for migraine treatment. Safety and implantation techniques require improvements since rates of lead migration, infection, and persistent stimulator-related pain continue to be high. Existing data justify further ONS trials with carefully chosen primary outcome(s), adequate statistical power, and improved surgical techniques.
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Sacral neuromodulation (SNM) is a minimally invasive therapeutic option for many voiding dysfunction conditions. It is approved by the US FDA for refractory overactive bladder with and without incontinence and nonobstructive retention. Since SNM has shown a favorable response for these approved indications, other therapeutic applications have been proposed for various conditions such as painful bladder syndrome, chronic pelvic pain and neurological voiding dysfunction in both adult and pediatric age groups. ⋯ The electrode is then connected to a battery-operated pulse generator. All patients need to have a test trial period before definitive device insertion. Here we discuss SNM therapy in functional urinary disorders and the technique of device insertion with the potential pitfalls.
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Phrenic nerve stimulation is a technique used to reanimate the diaphragm of patients with central nervous system etiologies of respiratory insufficiency. Current clinical indications include congenital central hypoventilation syndrome, spinal cord injury above C4, brain stem injury, and idiopathic severe sleep apnea. Presurgical evaluation ensures proper patient selection by validating the intact circuit from the phrenic nerve through alveolar oxygenation. ⋯ After implantation, each patient progresses through a conditioning phase that strengthens the diaphragm and progressively provides independence from the mechanical ventilator. Studies indicate that patients and families experience an improved quality of life and are satisfied with the results. Phrenic nerve stimulation provides a safe and effective means for reanimating the diaphragm for certain patients with respiratory insufficiency, providing independence from mechanical ventilation.