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Objectives The objective of this study was to present results from a multicenter registry designed to obtain longitudinal clinical outcome data for patients implanted with a neuromodulation system for the management of chronic pain of the trunk and/or limbs. Materials and Methods Interim data from 579 patients across 40 study sites were analyzed from a prospective, observational, noninterventional registry. Institutional review board approval was obtained prior to enrollment. The following were recorded at baseline and at 3, 6, and 12 months postimplant: patient-reported pain relief, categorical ratings of pain relief, Pain Disability Index (PDI) scores, quality of life, medication usage, and patient satisfaction. Pain relief among (tobacco) smokers was also assessed. Descriptive statistics were compiled for all patient outcome measurements, and data are reported as mean (±standard deviation). All statistical analysis was conducted using one-sided t-tests with a significance level of α = 0.05. Device-related adverse events were captured and are reported. Results Patient-reported pain relief was 58.0% (±26.2%) at 3 months, 58.1% (±28.7%) at 6 months, and 57.0% (±29.4%) at 12 months. Mean PDI scores were reduced from 47.7 points at baseline to 33.3, 32.4, and 31.9 points, respectively (p ≤ 0.001). The majority of patients categorized their pain relief as “excellent” or “good” and reported their overall quality of life as “greatly improved” or “improved” at all time points. In addition, greater than 79% of patients were “satisfied” or “very satisfied” with the therapy at all time points assessed, and 47.1% of patients “stopped” or “decreased” use of narcotics/opioids. Pain relief was significantly attenuated by smoking (p = 0.042). The most common adverse event was persistent pain and/or numbness at implantable pulse generator/lead site, which accounted for 18.6% of all events in 3.2% of all patients. Conclusions These results provide evidence to further support the safety, efficacy, and sustainability of neuromodulation in clinical practice.

Occipital nerve stimulation (ONS) is a peripheral nerve stimulation (PNS) technique that has been used with success in the management of intractable chronic daily headaches (CDHs) and occipital neuralgia (ON). The technique involves the placement of a stimulating surgical or percutaneous electrode over the occipital nerves within the subcutaneous tissues at the skull base. Until recently, procedures involving the occipital nerves were based on identifying bony or arterial landmarks with direct palpation or fluoroscopy. Although universally accepted as an imaging technique, fluoroscopy does not provide real-time imaging of the occipital nerves or vessels. Furthermore, therapeutic efficacy of ONS is directly related to the ability of the stimulating electrode to produce peripheral nerve dermatomal paresthesia, emphasizing the need for precision placement. A total of six patients, diagnosed with refractory CDH and ON, after failing extensive medical management, were diagnosed as potential candidates for ONS. Subsequently, all underwent successful percutaneous trials of bilateral octopolar (Advanced Neuromodulation Systems, Plano, TX, USA) ONS under ultrasound guidance, followed by permanent surgical implantation. In this case series, ultrasound provided accurate, real-time placement of introducer needles and stimulating electrodes by allowing visualization of tissue planes (epidermis, dermis, subcutaneous fat, and trapezious muscle), as well as vessels and nervous structures. Ultrasound imaging has been used increasingly for peripheral nerve blockade in surgical anesthesia and in chronic pain management as it allows real-time localization of both nervous and vascular structures (color flow Doppler) and, thus, a method for increasing blockade precision and safety. As an adjunct to ONS, the position of the introducer needles and electrodes can be visualized in relation to the occipital nerves and vasculature. This reproducible positioning allows accurate depth of placement (assuring production of the prerequisite PNS dermatomal paresthesia required for ONS efficacy) and limits the risk of injury to the occipital artery or nerve(s). In this case series, ultrasonography provided real-time, safe, and reliable placement of ONS electrodes. It also allowed identification of nervous and vascular structures unable to be seen with fluoroscopy, The portable nature of modern ultrasound machines, together with an ever improving pixelation of the Doppler color flow images/real-time measurements, and a lack of radiation exposure make this technology an attractive emerging modality in the field of Neuromodulation.