Comparison of two different laser photobiomodulation protocols on the viability of random skin flap in rats.

To identify the best low level laser photobiomodulation application site at the same irradiation time to increase the viability of the skin flap in rats. Eighteen male rats (Rattus norvegicus: var. Albinus, Rodentia Mammalia) were randomly distributed into three groups (n = 6). Group I (GI) was submitted to simulated laser photobiomodulation; group II (GII) was submitted to laser photobiomodulation at three points in the flap cranial base, and group III (GIII) was submitted to laser photobiomodulation at 12 points distributed along the flap. All groups were irradiated with an Indium, Galium, Aluminum, and Phosphorus diode laser (InGaAlP), 660 nm, with 50 mW power, irradiated for a total time of 240 s in continuous emission mode. The treatment started immediately after performing the cranial base random skin flap (10 × 4 cm2 dimension) and reapplied every 24 h, with a total of five applications. The animals were euthanized after the evaluation of the percentage of necrosis area, and the material was collected for histological analysis on the seventh postoperative day. GII animals presented a statistically significant decrease for the necrosis area when compared to the other groups, and a statistically significant increase in the quantification of collagen when compared to the control. We did not observe a statistical difference between the TGFß and FGF expression in the different groups evaluated. The application of laser photobiomodulation at three points of the flap cranial base was more effective than at 12 points regarding the reduction of necrosis area.

Meta-analysis of transcutaneous electrical nerve stimulation for relief of spinal pain.

We conducted a systematic review and meta-analysis analysing the existing data on transcutaneous electrical nerve stimulation (TENS) or interferential current (IFC) for chronic low back pain (CLBP) and/or neck pain (CNP) taking into account intensity and timing of stimulation, examining pain, function and disability. Seven electronic databases were searched for TENS or IFC treatment in non-specific CLBP or CNP. Four reviewers independently selected randomized controlled trials (RCTs) of TENS or IFC intervention in adult individuals with non-specific CLBP or CNP. Primary outcomes were for self-reported pain intensity and back-specific disability. Two reviewers performed quality assessment, and two reviewers extracted data using a standardized form. Nine RCTs were selected (eight CLBP; one CNP), and seven studies with complete data sets were included for meta-analysis (655 participants). For CLBP, meta-analysis shows TENS/IFC intervention, independent of time of assessment, was significantly different from placebo/control (p < 0.02). TENS/IFC intervention was better than placebo/control, during therapy (p = 0.02), but not immediately after therapy (p = 0.08), or 1-3 months after therapy (p = 0.99). Analysis for adequate stimulation parameters was not significantly different, and there was no effect on disability. This systematic review provides inconclusive evidence of TENS benefits in low back pain patients because the quality of the studies was low, and adequate parameters and timing of assessment were not uniformly used or reported. Without additional high-quality clinical trials using sufficient sample sizes and adequate parameters and outcome assessments, the outcomes of this review are likely to remain unchanged. SIGNIFICANCE: These data highlight the need for additional high-quality RCTs to examine the effects of TENS in CLBP. Trials should consider intensity of stimulation, timing of outcome assessment and assessment of pain, disability and function.

Effects of the carrier frequency of interferential current on pain modulation and central hypersensitivity in people with chronic nonspecific low back pain: A randomized placebo-controlled trial.

BACKGROUND: Interferential current (IFC) is commonly used for pain relief, but the effects of carrier frequency of the current and its action on pain mechanisms remain unclear. This randomized placebo-controlled trial tested the effects of IFC in people with chronic nonspecific low back pain. METHODS: One hundred and fifty participants were randomly allocated into three groups: 1 kHz, 4 kHz and placebo. The primary outcomes were pain intensity at rest in the first session (immediate effect of the IFC), after 12 sessions, 4 months after randomization (follow-up) and during movement (first and last session). The secondary outcomes were disability, global perceived effect, functional performance, discomfort caused by the IFC, use of analgesics and physiological measures of pain. RESULTS: Only during the first session, there was a significant decrease in pain intensity in the active groups. However, there were no differences in the improvement of pain at rest or during movement in the active groups compared to the placebo group in the remaining sessions. The frequency use of analgesics was significantly decreased in the active groups. For pain physiology measures, there was a significant increase in pressure pain thresholds in both active groups compared to the placebo group and a reduction in the temporal summation in the 1 kHz group compared to the other groups. CONCLUSIONS: These results suggest that although the IFC has changed some physiological mechanisms of pain and showed decrease frequency use of pain medication, there was no change in the primary aim, pain intensity. WHAT DOES THIS STUDY ADD?: The interferential current (IFC) presented advantages in the physiological measures of pain and showed decrease frequency use of pain medication. Future studies should investigate analgesic intake with IFC treatment.

Effects of TENS in living kidney donors submitted to open nephrectomy: a randomized placebo-controlled trial.

BACKGROUND: Pain is a negative factor in the recovery process of postoperative patients. It causes pulmonary alterations and complications, and it also affects functional capacity. Several studies have investigated the effects of transcutaneous electrical nerve stimulation (TENS) during the postoperative period. However, no studies have assessed the effects of TENS on kidney donors. Thus, the aim of the present study was to evaluate the effect of TENS on pain, walking function, respiratory muscle strength and vital capacity in kidney donors. METHODS: Seventy-four patients were randomly allocated into two groups: active TENS or placebo TENS. All patients were assessed for pain intensity, respiratory muscle strength, vital capacity and walking function before and after the TENS application on the first day of the postoperative period. RESULTS: The use of active TENS significantly reduced pain at rest (p = 0.006), during the measurement of maximal inspiratory pressure (p = 0.006), during maximal expiratory pressure (p = 0.004) and during vital capacity (p = 0.013). Active TENS also produced a significant increase in maximal expiratory pressure when compared with the placebo TENS group (p = 0.001). Maximal inspiratory pressure, vital capacity and walking function were not significantly different between the two treatment groups. CONCLUSIONS: These results suggest that TENS decreases pain intensity at rest and during respiratory manoeuvres and increases maximal expiratory pressure during the postoperative period in kidney donors after open nephrectomy.

Transcutaneous electrical nerve stimulation and conditioned pain modulation influence the perception of pain in humans.

BACKGROUND: Research in animal models suggests that transcutaneous electrical nerve stimulation (TENS) and conditioned pain modulation (CPM) produce analgesia via two different supraspinal pathways. No known studies have examined whether TENS and CPM applied simultaneously in human subjects will enhance the analgesic effect of either treatment alone. The purpose of the current study was to investigate whether the simultaneous application of TENS and CPM will enhance the analgesic effect of that produced by either treatment alone. METHODS: Sixty healthy adults were randomly allocated into two groups: (1) CPM plus active TENS; (2) CPM plus placebo TENS. Pain threshold for heat (HPT) and pressure (PPT) were recorded from subject's left forearm at baseline, during CPM, during active or placebo TENS, and during CPM plus active or placebo TENS. CPM was induced by placing the subjects' contralateral arm in a hot water bath (46.5 °C) for 2 min. TENS (100 µs, 100 Hz) was applied to the forearm for 20 min at a strong but comfortable intensity. RESULTS: Active TENS alone increased PPT (but not HPT) more than placebo TENS alone (p = 0.011). Combining CPM and active TENS did not significantly increase PPT (p = 0.232) or HPT (p = 0.423) beyond CPM plus placebo TENS. There was a significant positive association between PPT during CPM and during active TENS (r(2) = 0.46; p = 0.003). CONCLUSIONS: TENS application increases PPT; however, combining CPM and TENS does not increase the CPM's hypoalgesic response. CPM effect on PPT is associated with the effects of TENS on PPT.