Biopsychosocial Aspects in Individuals with Acute and Chronic Rotator Cuff Related Shoulder Pain: Classification Based on a Decision Tree Analysis

Biopsychosocial aspects seem to influence the clinical condition of rotator cuff related shoulder pain (RCRSP). However, traditional bivariate and linear analyses may not be sufficiently robust to capture the complex relationships among these aspects. This study determined which biopsychosocial aspects would better classify individuals with acute and chronic RCRSP and described how these aspects interact to create biopsychosocial phenotypes in individuals with acute and chronic RCRSP. Individuals with acute (<six months of pain, n = 15) and chronic (≥six months of pain, n = 38) RCRSP were included. Sociodemographic data, biological data related to general clinical health status, to shoulder clinical condition and to sensory function, and psychosocial data were collected. Outcomes were compared between groups and a decision tree was used to classify the individuals with acute and chronic RCRSP into different phenotypes hierarchically organized in nodes. Only conditioned pain modulation was different between the groups. However, the tree combined six biopsychosocial aspects to identify seven distinct phenotypes in individuals with RCRSP: three phenotypes of individuals with acute, and four with chronic RCRSP. While the majority of the individuals with chronic RCRSP have no other previous painful complaint besides the shoulder pain and low efficiency of endogenous pain modulation with no signs of biomechanical related pain, individuals with acute RCRSP are more likely to have preserved endogenous pain modulation and unilateral pain with signs of kinesiophobia

The influence of stimulus phase duration on discomfort and electrically induced torque of quadriceps femoris

BACKGROUND: Although a number of studies have compared the influence of different electrical pulse parameters on maximum electrically induced torque (MEIT) and discomfort, the role of phase duration has been poorly investigated. OBJECTIVE: To examine the variation in muscle torque and discomfort produced when electrically stimulating quadriceps femoris using pulsed current with three different phase durations in order to establish whether there are any advantages or disadvantages in varying the phase duration over the range examined. METHOD: This is a two repeated-measures, within-subject study conducted in a research laboratory. The study was divided into 2 parts with 19 healthy young adults in each part.In part 1, MEIT was determined for each phase duration (400, 700, and 1000 &#181;s), using a biphasic pulsed current at a frequency of 50 Hz. In part 2, stimulus amplitude was increased until the contractions reached 40% of maximum voluntary isometric contraction (MVIC) and the associated discomfort produced by each phase duration was measured. RESULTS: In part 1 of the study, we found that the average MEITs generated with each phase duration (400, 700, and 1000 &#181;s) were 55.0, 56.3, and 58.0% of MVIC respectively, but the differences were not statistically significant (p=.45). In part 2, we found a statistically significant increase in discomfort over the same range of phase durations. The results indicate that, for a given level of torque production, discomfort increases with increasing phase duration (p=.008). CONCLUSIONS: Greater muscle torque cannot be produced by increasing the stimulus phase duration over the range examined. Greater discomfort is produced by increasing the stimulus phase duration

High voltage pulsed current in collagen realignment, synthesis, and angiogenesis after Achilles tendon partial rupture

ABSTRACT Objective To verify the efficacy of high voltage pulsed current in collagen realignment and synthesis and in angiogenesis after the partial rupturing of the Achilles tendon in rats. Method Forty male Wistar rats were randomized into four groups of 10 animals each: sham, cathodic stimulation, anodic stimulation, and alternating stimulation. Their Achilles tendons were submitted to direct trauma by a free-falling metal bar. Then, the treatment was administered for six consecutive days after the injury. In the simulation group, the electrodes were positioned on the animal, but the device remained off for 30 minutes. The other groups used a frequency of 120 pps, sensory threshold, and the corresponding polarity. On the seventh day, the tendons were removed and sent for histological slide preparation for birefringence and Picrosirius Red analysis and for blood vessel quantification. Results No significant difference was observed among the groups regarding collagen realignment (types I or III collagen) or quantity of blood vessels. Conclusion High voltage pulsed current for six consecutive days was not effective in collagen realignment, synthesis, or angiogenesis after the partial rupturing of the Achilles tendon in rats

Can transcutaneous electrical nerve stimulation improve achilles tendon healing in rats?

BACKGROUND: Tendon injury is one of the most frequent injuries in sports activities. TENS is a physical agent used in the treatment of pain but its influence on the tendon's healing process is unclear. OBJECTIVE: To evaluate the influence of TENS on the healing of partial rupture of the Achilles tendon in rats. METHOD: Sixty Wistar rats were submitted to a partial rupture of the Achilles tendon by direct trauma and randomized into six groups (TENS or Sham stimulation) and the time of evaluation (7, 14, and 21 days post-injury). Burst TENS was applied for 30 minutes, 6 days, 100 Hz frequency, 2 Hz burst frequency, 200 µs pulse duration, and 300 ms pulse train duration. Microscopic analyses were performed to quantify the blood vessels and mast cells, birefringence to quantify collagen fiber alignment, and immunohistochemistry to quantify types I and III collagen fibers. RESULTS: A significant interaction was observed for collagen type I (p=0.020) where the TENS group presented lower percentage in 14 days after the lesion (p=0.33). The main group effect showed that the TENS group presented worse collagen fiber alignment (p=0.001) and lower percentage of collagen III (p=0.001) and the main time effect (p=0.001) showed decreased percentage of collagen III at 7 days (p=0.001) and 14 days (p=0.001) after lesion when compared to 21 days. CONCLUSIONS: Burst TENS inhibited collagen I and III production and impaired its alignment during healing of partial rupture of the Achilles tendon in rats

Does Preoperative Electrical Stimulation of the Skin Alter the Healing Process?

Background. in vitro studies have demonstrated that electrical current may affect fibroblast proliferation and synthesis of collagen fibers. in humans, the application of electrical current by positioning the positive electrode on skin wounds resulted in thinner hypertrophic scars. the aim of this study was to evaluate the effects of preoperative electrical stimulation on cutaneous wound healing in rats.Materials and Methods. Forty rats were divided into two groups of 20 animals each. in the control group, an incision was made on the back of the animals. in the stimulation group, a preoperative electrical stimulation was applied using a rectangular pulse current at a frequency of 7.7 Hz, and intensity of 8 mA, for 30 min, with the positive electrode placed on the back of the animal, and the negative electrode placed on the abdominal wall. Following, an incision was made on their back. Biopsy was carried out on postoperative day 7 and 14, and histologic analysis was performed.Results. the number of newly formed vessels, fibroblasts, and type III collagen fibers in the stimulation group on postoperative day 7 were greater than those in the control group.Conclusions. Preoperative positive-polarity electrical stimulation positively affects angiogenesis and fibroblast proliferation. (C) 2011 Elsevier Inc. All rights reserved.Universidade Federal de São Paulo UNIFESP, Disciplina Cirurgia Plast, Dept Surg, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Pathol, BR-04024002 São Paulo, BrazilUniv City São Paulo UNICID, Phys Therapy Dept, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Disciplina Cirurgia Plast, Dept Surg, BR-04024002 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Pathol, BR-04024002 São Paulo, BrazilWeb of Scienc

Effect of Low-Level Laser Therapy with Output Power of 30mW and 60mW in the Viability of a Random Skin Flap

Objective: To assess the effects of low-level laser therapy (LLLT) with output power of 30 and 60mW in the viability of a random skin flap in rats. Background Data: Output power values in LLLT are not well defined. Materials and Methods: Controlled, single-blind experimental study. Thirty-six animals were randomly distributed into three groups: sham group (SG), 30-mW output power (30G), and 60-mW output power (60G). in both treated groups, a fluency of 3 J/cm(2) was used. Two minutes after elevation of a random-pattern cranially based dorsal flap (4x10 cm), laser irradiation was applied and repeated on the first, second, third, and fourth postoperative days. Percentages of flap necrosis were calculated on the seventh postoperative day. Also, four fragments of each flap were collected to allow determination of the percentages of vascular density according to the bidimensional method of the morphometric analysis of blood vessels. Statistical analysis included the Wilcoxon test and Kruskal-Wallis variance analysis. A significance level of 5% was elected (p<0.05). Results: Laser-treated animals presented significantly less necrosis than the sham group (SG, 53%; 30G, 24%; p<0.05) (60G, 25%; p<0.05). Also, laser-treated animals presented significantly more vascular density than the sham group (SG, 37%; 30G, 57%; p<0.05) (60G, 59%; p<0.05). Conclusion: LLLT (660 nm) with 30-mW and 60-mW output power was efficient in the increase of skin flap viability, but there was no difference between them.Universidade Federal de São Paulo, Div Plast Surg, São Paulo, BrazilUniversidade Federal de São Paulo, Div Pathol, São Paulo, BrazilUniversidade Federal de São Paulo, Div Plast Surg, São Paulo, BrazilUniversidade Federal de São Paulo, Div Pathol, São Paulo, BrazilWeb of Scienc

Low-level laser therapy and light-emitting diode effects in the secretion of neuropeptides SP and CGRP in rat skin

The phototherapy effects in the skin are related to biomodulation, usually to accelerate wound healing. However, there is no direct proof of the interrelation between the effects of low-level laser therapy (LLLT) and light-emitting diode (LED) in neuropeptide secretion, these substances being prematurely involved in the neurogenic inflammation phase of wound healing. This study therefore focused on investigating LLLT and LED in Calcitonin gene-related peptide (CGRP) and substance P (SP) secretion in healthy rat skin. Forty rats were randomly distributed into five groups with eight rats each: Control Group, Blue LED Group (470 nm, 350 mW power), Red LED Group (660 nm, 350 mW power), Red Laser Group (660 nm, 100 mW power), and Infrared Laser Group (808 nm, 100 mW power) (DMCA (R) Equipamentos Ltda., So Carlos, So Paulo, Brazil). the skin of the animals in the experimental groups was irradiated using the punctual contact technique, with a total energy of 40 J, single dose, standardized at one point in the dorsal region. After 14 min of irradiation, the skin samples were collected for CGRP and SP quantification using western blot analysis. SP was released in Infrared Laser Group (p = 0.01); there was no difference in the CGRP secretion among groups. Infrared (808 nm) LLLT enhances neuropeptide SP secretion in healthy rat skin.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo UNIFESP, BR-04023002 São Paulo, BrazilUniv São Paulo, Dept Neurol, BR-01246903 São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, BR-04023002 São Paulo, BrazilWeb of Scienc