Percutaneous electrical nerve stimulation: a novel analgesic therapy for diabetic neuropathic pain.

OBJECTIVE: To evaluate the use of percutaneous electrical nerve stimulation (PENS) in the management of patients with painful diabetic peripheral neuropathy. RESEARCH DESIGN AND METHODS: A total of 50 adult patients with type 2 diabetes and peripheral neuropathic pain of >6 months duration involving the lower extremities were randomly assigned to receive active PENS (needles with electrical stimulation at an alternating frequency of 15 and 30 Hz) and sham (needles only) treatments for 3 weeks. Each series of treatments was administered for 30 min three times a week according to a standardized protocol. After a 1-week washout period, all patients were subsequently switched to the other modality. A 10-cm visual analog scale (VAS) was used to assess pain, physical activity, and quality of sleep before each session. The changes in VAS scores and daily requirements for oral analgesic medication were determined during each 3-week treatment period. Patients completed the MOS 36-Item Short-Form Health Survey (SF-36), the Beck Depression Inventory (BDI), and the Profile of Mood States (POMS) before and after completion of each treatment modality. At the end of the crossover study, a patient preference questionnaire was used to compare the effectiveness of the two modalities. RESULTS: Compared with the pain VAS scores before active (6.2 +/- 1.0) and sham (6.4 +/- 0.9) treatments, pain scores after treatment were reduced to 2.5 +/- 0.8 and 6.3 +/- 1.1, respectively. With active PENS treatment, the VAS activity and sleep scores were significantly improved from 5.2 +/- 1.0 and 5.8 +/- 1.3 to 7.9 +/- 1.0 and 8.3 +/- 0.7, respectively. The VAS scores for pain, activity, and sleep were unchanged from baseline values after the sham treatments. Patients' daily oral nonopioid analgesic requirements decreased by 49 and 14% after active and sham PENS treatments, respectively. The post-treatment physical and mental components of the SF-36, the BDI, and the POMS all showed a significantly greater improvement with active versus sham treatments. Active PENS treatment improved the neuropathic pain symptoms in all patients. CONCLUSIONS: PENS is a useful nonpharmacological therapeutic modality for treating diabetic neuropathic pain. In addition to decreasing extremity pain, PENS therapy improved physical activity, sense of well-being, and quality of sleep while reducing the need for oral nonopioid analgesic medication.

Percutaneous neuromodulation therapy: does the location of electrical stimulation effect the acute analgesic response?

We studied the effect of the location of electrical stimulation on the acute analgesic response to percutaneous neuromodulation therapy in patients with nonradiating neck pain. Sixty-eight patients received three different nonpharmacologic modalities, namely "needles only" (neck), local (neck) dermatomal stimulation, and remote (lower back) dermatomal stimulation in a random sequence over the course of an 11-wk study period. All treatments were given for 30 min, 3 times per week for 3 wk, with 1 wk "off" between each modality. The assessment tools included the health status survey short form (SF-36) questionnaire, as well as 10-cm visual analog scales for assessing pain, physical activity, and quality of sleep. The pain visual analog scale was repeated 5-10 min after each treatment session. The daily oral nonopioid analgesic requirements were recorded in the patient diary during the entire study period. At the end of each 3-wk treatment block, the SF-36 questionnaire was repeated. Compared with needles only and remote dermatomal stimulation, local dermatomal stimulation produced a significantly greater decrease in pain (38%+/-17% vs 9%+/- 16% and 13%+/-18%), increase in physical activity (41%+/-21% vs 11% +/-17% and 16%+/-15%), and improvement in the quality of sleep (34% +/-18% vs 7%+/-17% and 10%+/-18%) compared with baseline values (P<0.05). The need for oral analgesic medications was decreased by an average of 6%+/-15%, 37%+/-18%, and 9%+/-13% during the 3-wk treatment period with the needle only, local dermatomal, and remote dermatomal stimulation, respectively. The posttreatment SF-36 test results revealed that all three modalities produced improvements compared with the prestudy scores for both the physical component summary and mental component summary. However, the magnitude of the changes in the physical component summary and mental component summary with local dermatomal stimulation was significantly greater (+7.9 and +3.6, respectively) than needle only (+3.4 and +1.7, respectively) or remote dermatomal stimulation (+3.7 and +1.9, respectively). No side effects were reported at the needle insertion sites. We conclude that electrical stimulation at the specific dermatomal levels corresponding to the local pathology produces greater short-term improvements in pain control, physical activity, and quality of sleep in patients with chronic neck pain.

The effect of montage on the analgesic response to percutaneous neuromodulation therapy.

The analgesic response to percutaneous neuromodulation therapy (PNT) is influenced by the location, frequency, and duration of electrical stimulation. We evaluated the effect of different patterns of stimulation (montages) on the acute analgesic response to PNT when applied at the same dermatomal levels in 72 consenting patients with low back pain. All of the patients received a standardized montage (I) and three alternative montage (II-IV) patterns according to a randomized, single-blinded, crossover study design. All of the PNT treatments were administered at identical alternating stimulation frequencies of 15 and 30 Hz for a period of 30 min, three times per week for two consecutive weeks, with 1 wk "off" between each modality. Pretreatment assessments included the health status survey short form (SF-36) questionnaire, as well as visual analog scale scores for pain, physical activity, and quality of sleep (with 0 = the best to 10 = the worst). The pain visual analog scale was repeated 5--10 min after each treatment session. The daily oral analgesic usage was recorded in a patient diary. All four montages produced significant improvements in pain (42%--64%), physical activity (35%--51%), and quality of sleep (28%--46%), as well as 23% to 47% reductions in the daily oral analgesic usage. However, Montage II was significantly more effective than the standard (Montage I) and the other two montages studied. These data suggest that the pattern of stimulation (i.e., montage) can influence the acute analgesic response to PNT.

Effect of the duration of electrical stimulation on the analgesic response in patients with low back pain.

BACKGROUND: Electrical stimulation of peripheral nerves produces acute analgesic effects. This randomized, sham-controlled, crossover study was designed to evaluate the effect of differing durations of electrical stimulation on the analgesic response to percutaneous electrical nerve stimulation in 75 consenting patients with low back pain. METHODS: All patients received electrical stimulation for four different time intervals (0, 15, 30, and 45 min) in a random sequence over the course of an 11-week study period. All active percutaneous electrical nerve stimulation treatments were administered using alternating frequencies of 15 and 30 Hz three times per week for 2 consecutive weeks. The prestudy assessments included the health status survey short form questionnaire and 10-cm visual analog scale scores for pain, physical activity, and quality of sleep, with 0 being the best and 10 being the worst. The pain scoring was repeated 5-10 min after each 60-min study session and 24 h after the last treatment session with each of the four methods. The daily oral analgesic requirements were assessed during each of the four treatment blocks. At the end of each 2-week treatment block, the questionnaire was repeated. RESULTS: Electrical stimulation using percutaneously placed needles produced short-term improvements in the visual analog scale pain, physical activity, and quality of sleep scores, and a reduction in the oral analgesic requirements. The 30-min and 45-min durations of electrical stimulation produced similar hypoalgesic effects (48+/-21% and 46+/-19%, respectively) and were significantly more effective than either 15 min (21+/-17%) or 0 min (10+/-11%). The 30- and 45-min treatments were also more effective in improving physical activity and sleep scores over the course of the 2-week treatment period. In contrast to the sham treatment (0 min), the health status survey short form revealed that electrical stimulation for 15 to 45 min three times per week for 2 weeks improved patient function. CONCLUSION: The recommended duration of electrical stimulation with percutaneous electrical nerve stimulation therapy is 30 min.

The effect of stimulus frequency on the analgesic response to percutaneous electrical nerve stimulation in patients with chronic low back pain.

UNLABELLED: Low back pain (LBP) is one of the most common medical problems in our society. Increasingly, patients are turning to nonpharmacologic analgesic therapies such as percutaneous electrical nerve stimulation (PENS). We designed this sham-controlled study to compare the effect of three different frequencies of electrical stimulation on the analgesic response to PENS therapy. Sixty-eight consenting patients with LBP secondary to degenerative lumbar disc disease were treated with PENS therapy at 4 Hz, alternating 15 Hz and 30 Hz (15/30 Hz), and 100 Hz, as well as sham-PENS (0 Hz), according to a randomized, cross-over study design. Each treatment was administered for a period of 30 min three times per week for 2 wk. The pre- and posttreatment assessments included the health status survey short form and visual analog scales for pain, physical activity, and quality of sleep. After receiving all four treatments, patients completed a global assessment questionnaire. The sham-PENS treatments failed to produce changes in the degree of pain, physical activity, sleep quality, or daily intake of oral analgesic medications. In contrast, 4-Hz, 15/30-Hz, and 100-Hz stimulation all produced significant decreases in the severity of pain, increases in physical activity, improvements in the quality of sleep, and decreases in oral analgesic requirements (P < 0.01). Of the three frequencies, 15/30 Hz was the most effective in decreasing pain, increasing physical activity, and improving the quality of sleep (P < 0.05). In the global assessment, 40% of the patients reported that 15/30 Hz was the most desirable therapy, and it was also more effective in improving the patient's sense of well-being. We conclude that the frequency of electrical stimulation is an important determinant of the analgesic response to PENS therapy. Alternating stimulation at 15-Hz and 30-Hz frequencies was more effective than either 4 Hz or 100 Hz in improving outcome measures in patients with LBP. IMPLICATIONS: The frequency of electrical stimulation seems to be an important determinant of the analgesic efficacy of percutaneous electrical nerve stimulation. Mixed low- and high-frequency stimulation was more effective than either low or high frequencies alone in the treatment of patients with low back pain.