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Objectives This study aimed to assess the analgesic effect of kilohertz alternating current applied to the severed nerves in amputees afflicted by intractable limb pain. Methods Ten lower-limb amputees with chronic and severe residual limb pain or phantom limb pain who attained significant pain reduction after local nerve block injection were enrolled. A cuff electrode was wrapped around the sciatic or tibial nerve. An external waveform generator was used for the main part of the study, while an implantable generator was developed and implanted in the responders after 9 to 12 months. Sinusoidal waveforms of 10 kHz and up to 10 V were applied for 30 min during each subject-initiated treatment session. A diary was used to record pain intensities before and after each session. Results Among the seven subjects who received treatment, the average pain reduction was 75% at the three-month primary end point. These subjects were responders per predefined criterion of achieving ≥50% pain reduction in ≥50% of treatment sessions for the three-month end point. Pain medication use and interference of pain on functions was significantly reduced. The treatment efficacy was sustained through the follow-up period of up to 12 months. Besides dislodgement and loss of function for one electrode in one subject, all other devices functioned as intended. No changes of residual motor and sensory function were observed. Conclusion This pilot study generated preliminary evidence on the efficacy and safety of kilohertz electrical nerve block for postamputation pain, justifying a pivotal study for regulatory approval.

Postamputation residual limb pain is often a disabling chronic pain condition. Oftentimes, patients are left with a chronic stump pain that is refractory to current pain management modalities, such as medications, peripheral nerve blocks or denervation techniques, nerve or spinal cord stimulation, or surgical revision. Using high-frequency alternating current via a peripheral nerve cuff electrode creates a complete depolarizing nerve block, which blocks painful or unwanted nerve transmission of pain signals; the cuff is placed proximal to the neuroma at the end of the severed nerve. This article demonstrates the technique of placing a peripheral nerve cuff surgically around the peripheral nerves of patients who suffer from debilitating stump pain with lower extremity amputations. In total, 10 patients were implanted with the nerve cuff with 9 patients receiving in-clinic testing and 7 patients progressing onto long-term home-use. The average numerical rating scale pain scale for tested patients decreased from 5.7-1.4 (out of 10) after high-frequency alternating current electrical nerve block therapy with 85% of all testing sessions yielding a >50% pain reduction. Additionally, patients noted improved ability to maintain activity of daily living, as well as noted improvement of quality of life scores, and a reduction in overall pain medication use. Although the study’s initial endpoint was 90 days, we have continued to follow our implanted patients who have now reached 36 months.

The objective of this review is to describe and visually depict techniques of percutaneous vertebral augmentation for treatment of painful vertebral compressive fractures. During those vertebral augmentation techniques (kypho- or vertebroplasty), bone cement, frequently polymethylmethacrylate, is injected into the vertebral body. In addition, during kyphoplasty, inflated balloons called “tamps” are placed in the vertebral body, creating the cavity before the cement injection. These procedures are most often performed in a percutaneous fashion on an outpatient basis. The mechanism of pain relief is unknown, but it is likely that stabilization of the fracture and destruction of the nociceptors lead to analgesia. Complications of such procedures are few, but some of them can be serious. Those include severe spinal canal stenosis from leaking cement with possible spinal cord or nerve root compression and venous and pulmonary embolism. Patient selection is very important and is discussed below.